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Sample records for increased chemokine signaling

  1. Chemokine Oligomerization in Cell Signaling and Migration

    PubMed Central

    Wang, Xu; Sharp, Joshua S.; Handel, Tracy M.; Prestegard, James H.

    2014-01-01

    Chemokines are small proteins best known for their role in controlling the migration of diverse cells, particularly leukocytes. Upon binding to their G-protein-coupled receptors on the leukocytes, chemokines stimulate the signaling events that cause cytoskeletal rearrangements involved in cell movement, and migration of the cells along chemokine gradients. Depending on the cell type, chemokines also induce many other types of cellular responses including those related to defense mechanisms, cell proliferation, survival, and development. Historically, most research efforts have focused on the interaction of chemokines with their receptors, where monomeric forms of the ligands are the functionally relevant state. More recently, however, the importance of chemokine interactions with cell surface glycosaminoglycans has come to light, and in most cases appears to involve oligomeric chemokine structures. This review summarizes existing knowledge relating to the structure and function of chemokine oligomers, and emerging methodology for determining structures of complex chemokine assemblies in the future. PMID:23663982

  2. Lack of Chemokine Signaling through CXCR5 Causes Increased Mortality, Ventricular Dilatation and Deranged Matrix during Cardiac Pressure Overload

    PubMed Central

    Waehre, Anne; Husberg, Cathrine; Sjaastad, Ivar; Nygård, Ståle; Dahl, Christen P.; Ahmed, M. Shakil; Finsen, Alexandra V.; Reims, Henrik; Louch, William E.; Hilfiker-Kleiner, Denise; Vinge, Leif E.; Roald, Borghild; Attramadal, Håvard; Lipp, Martin; Gullestad, Lars; Aukrust, Pål; Christensen, Geir

    2011-01-01

    Rationale Inflammatory mechanisms have been suggested to play a role in the development of heart failure (HF), but a role for chemokines is largely unknown. Based on their role in inflammation and matrix remodeling in other tissues, we hypothesized that CXCL13 and CXCR5 could be involved in cardiac remodeling during HF. Objective We sought to analyze the role of the chemokine CXCL13 and its receptor CXCR5 in cardiac pathophysiology leading to HF. Methods and Results Mice harboring a systemic knockout of the CXCR5 (CXCR5−/−) displayed increased mortality during a follow-up of 80 days after aortic banding (AB). Following three weeks of AB, CXCR5−/− developed significant left ventricular (LV) dilatation compared to wild type (WT) mice. Microarray analysis revealed altered expression of several small leucine-rich proteoglycans (SLRPs) that bind to collagen and modulate fibril assembly. Protein levels of fibromodulin, decorin and lumican (all SLRPs) were significantly reduced in AB CXCR5−/− compared to AB WT mice. Electron microscopy revealed loosely packed extracellular matrix with individual collagen fibers and small networks of proteoglycans in AB CXCR5−/− mice. Addition of CXCL13 to cultured cardiac fibroblasts enhanced the expression of SLRPs. In patients with HF, we observed increased myocardial levels of CXCR5 and SLRPs, which was reversed following LV assist device treatment. Conclusions Lack of CXCR5 leads to LV dilatation and increased mortality during pressure overload, possibly via lack of an increase in SLRPs. This study demonstrates a critical role of the chemokine CXCL13 and CXCR5 in survival and maintaining of cardiac structure upon pressure overload, by regulating proteoglycans essential for correct collagen assembly. PMID:21533157

  3. Chemokine signaling: rules of attraction.

    PubMed

    Schier, Alexander F

    2003-03-04

    The chemokine SDF-1 and its receptor CXCR4 control cell migration in the immune and nervous systems. Recent studies in zebrafish have shown that SDF-1 and CXCR4 also guide the migration of germ cells and sensory organs of the lateral line.

  4. CXCR4 chemokine receptor signaling mediates pain in diabetic neuropathy

    PubMed Central

    2014-01-01

    Background Painful Diabetic Neuropathy (PDN) is a debilitating syndrome present in a quarter of diabetic patients that has a substantial impact on their quality of life. Despite this significant prevalence and impact, current therapies for PDN are only partially effective. Moreover, the cellular mechanisms underlying PDN are not well understood. Neuropathic pain is caused by a variety of phenomena including sustained excitability in sensory neurons that reduces the pain threshold so that pain is produced in the absence of appropriate stimuli. Chemokine signaling has been implicated in the pathogenesis of neuropathic pain in a variety of animal models. We therefore tested the hypothesis that chemokine signaling mediates DRG neuronal hyperexcitability in association with PDN. Results We demonstrated that intraperitoneal administration of the specific CXCR4 antagonist AMD3100 reversed PDN in two animal models of type II diabetes. Furthermore DRG sensory neurons acutely isolated from diabetic mice displayed enhanced SDF-1 induced calcium responses. Moreover, we demonstrated that CXCR4 receptors are expressed by a subset of DRG sensory neurons. Finally, we observed numerous CXCR4 expressing inflammatory cells infiltrating into the DRG of diabetic mice. Conclusions These data suggest that CXCR4/SDF-1 signaling mediates enhanced calcium influx and excitability in DRG neurons responsible for PDN. Simultaneously, CXCR4/SDF-1 signaling may coordinate inflammation in diabetic DRG that could contribute to the development of pain in diabetes. Therefore, targeting CXCR4 chemokine receptors may represent a novel intervention for treating PDN. PMID:24961298

  5. Timely interaction between prostaglandin and chemokine signaling is a prerequisite for successful fertilization.

    PubMed

    Tamba, Shigero; Yodoi, Rieko; Segi-Nishida, Eri; Ichikawa, Atsushi; Narumiya, Shuh; Sugimoto, Yukihiko

    2008-09-23

    Timely interaction between the egg and sperm is required for successful fertilization; however, little is known about the signaling therein. Prostaglandin (PG) E receptor EP2-deficient (Ptger2(-/-)) female mice exhibit a severe fertilization defect. We investigated the molecular events leading to this failure. We found increased gene expression for chemokines, such as Ccl2, Ccl7, and Ccl9, in Ptger2(-/-) cumulus cells (the somatic cells surrounding the egg) compared with wild-type cells. Furthermore, under physiological conditions, cumulus-derived chemokine signaling was found to have a dual action; CCL7 facilitates sperm migration to the cumulus-egg complex and integrin-mediated cumulus extracellular matrix (ECM) assembly to protect eggs. However, in the absence of PGE(2)-EP2 signaling, chronic CCL7 signaling results in excessive integrin engagement to the ECM, making the cumulus ECM resistant to sperm hyaluronidase, thereby preventing sperm penetration. Our findings indicate that PGE(2)-EP2 signaling negatively regulates the autocrine action of chemokines and prevents excessive cumulus ECM assembly. This interaction between PG and chemokine signaling is required for successful fertilization.

  6. Chemokines induce axon outgrowth downstream of Hepatocyte Growth Factor and TCF/β-catenin signaling

    PubMed Central

    Bhardwaj, Deepshikha; Náger, Mireia; Camats, Judith; David, Monica; Benguria, Alberto; Dopazo, Ana; Cantí, Carles; Herreros, Judit

    2013-01-01

    Axon morphogenesis is a complex process regulated by a variety of secreted molecules, including morphogens and growth factors, resulting in the establishment of the neuronal circuitry. Our previous work demonstrated that growth factors [Neurotrophins (NT) and Hepatocyte Growth Factor (HGF)] signal through β-catenin during axon morphogenesis. HGF signaling promotes axon outgrowth and branching by inducing β-catenin phosphorylation at Y142 and transcriptional regulation of T-Cell Factor (TCF) target genes. Here, we asked which genes are regulated by HGF signaling during axon morphogenesis. An array screening indicated that HGF signaling elevates the expression of chemokines of the CC and CXC families. In line with this, CCL7, CCL20, and CXCL2 significantly increase axon outgrowth in hippocampal neurons. Experiments using blocking antibodies and chemokine receptor antagonists demonstrate that chemokines act downstream of HGF signaling during axon morphogenesis. In addition, qPCR data demonstrates that CXCL2 and CCL5 expression is stimulated by HGF through Met/b-catenin/TCF pathway. These results identify CC family members and CXCL2 chemokines as novel regulators of axon morphogenesis downstream of HGF signaling. PMID:23641195

  7. Activated platelets signal chemokine synthesis by human monocytes.

    PubMed Central

    Weyrich, A S; Elstad, M R; McEver, R P; McIntyre, T M; Moore, K L; Morrissey, J H; Prescott, S M; Zimmerman, G A

    1996-01-01

    Human blood monocytes adhere rapidly and for prolonged periods to activated platelets that display P-selectin, an adhesion protein that recognizes a specific ligand on leukocytes, P-selectin glycoprotein-1. We previously demonstrated that P-selectin regulates expression and secretion of cytokines by stimulated monocytes when it is presented in a purified, immobilized form or by transfected cells. Here we show that thrombin-activated platelets induce the expression and secretion of monocyte chemotactic protein-1 and IL-8 by monocytes. Enhanced monokine synthesis requires engagement of P-selectin glycoprotein-1 on the leukocyte by P-selectin on the platelet. Secretion of the chemokines is not, however, directly signaled by P-selectin; instead, tethering of the monocytes by P-selectin is required for their activation by RANTES (regulated upon activation normal T cell expressed presumed secreted), a platelet chemokine not previously known to induce immediate-early gene products in monocytes. Adhesion of monocytes to activated platelets results in nuclear translocation of p65 (RelA), a component of the NF-kappaB family of transcription factors that binds kappaB sequences in the regulatory regions of monocyte chemotactic protein-1, IL-8, and other immediate-early genes. However, expression of tissue factor, a coagulation protein that also has a kappaB sequence in the 5' regulatory region of its gene, is not induced in monocytes adherent to activated platelets. Thus, contact of monocytes with activated platelets differentially affects the expression of monocyte products. These experiments suggest that activated platelets regulate chemokine secretion by monocytes in inflammatory lesions in vivo and provide a model for the study of gene regulation in cell-cell interactions. PMID:8617886

  8. New paradigms in chemokine receptor signal transduction: Moving beyond the two-site model.

    PubMed

    Kleist, Andrew B; Getschman, Anthony E; Ziarek, Joshua J; Nevins, Amanda M; Gauthier, Pierre-Arnaud; Chevigné, Andy; Szpakowska, Martyna; Volkman, Brian F

    2016-08-15

    Chemokine receptor (CKR) signaling forms the basis of essential immune cellular functions, and dysregulated CKR signaling underpins numerous disease processes of the immune system and beyond. CKRs, which belong to the seven transmembrane domain receptor (7TMR) superfamily, initiate signaling upon binding of endogenous, secreted chemokine ligands. Chemokine-CKR interactions are traditionally described by a two-step/two-site mechanism, in which the CKR N-terminus recognizes the chemokine globular core (i.e. site 1 interaction), followed by activation when the unstructured chemokine N-terminus is inserted into the receptor TM bundle (i.e. site 2 interaction). Several recent studies challenge the structural independence of sites 1 and 2 by demonstrating physical and allosteric links between these supposedly separate sites. Others contest the functional independence of these sites, identifying nuanced roles for site 1 and other interactions in CKR activation. These developments emerge within a rapidly changing landscape in which CKR signaling is influenced by receptor PTMs, chemokine and CKR dimerization, and endogenous non-chemokine ligands. Simultaneous advances in the structural and functional characterization of 7TMR biased signaling have altered how we understand promiscuous chemokine-CKR interactions. In this review, we explore new paradigms in CKR signal transduction by considering studies that depict a more intricate architecture governing the consequences of chemokine-CKR interactions.

  9. Chemokine 25–induced signaling suppresses colon cancer invasion and metastasis

    PubMed Central

    Chen, Huanhuan Joyce; Edwards, Robert; Tucci, Serena; Bu, Pengcheng; Milsom, Jeff; Lee, Sang; Edelmann, Winfried; Gümüs, Zeynep H.; Shen, Xiling; Lipkin, Steven

    2012-01-01

    Chemotactic cytokines (chemokines) can help regulate tumor cell invasion and metastasis. Here, we show that chemokine 25 (CCL25) and its cognate receptor chemokine receptor 9 (CCR9) inhibit colorectal cancer (CRC) invasion and metastasis. We found that CCR9 protein expression levels were highest in colon adenomas and progressively decreased in invasive and metastatic CRCs. CCR9 was expressed in both primary tumor cell cultures and colon-cancer-initiating cell (CCIC) lines derived from early-stage CRCs but not from metastatic CRC. CCL25 stimulated cell proliferation by activating AKT signaling. In vivo, systemically injected CCR9+ early-stage CCICs led to the formation of orthotopic gastrointestinal xenograft tumors. Blocking CCR9 signaling inhibited CRC tumor formation in the native gastrointestinal CCL25+ microenvironment, while increasing extraintestinal tumor incidence. NOTCH signaling, which promotes CRC metastasis, increased extraintestinal tumor frequency by stimulating CCR9 proteasomal degradation. Overall, these data indicate that CCL25 and CCR9 regulate CRC progression and invasion and further demonstrate an appropriate in vivo experimental system to study CRC progression in the native colon microenvironment. PMID:22863617

  10. CXCR3: latest evidence for the involvement of chemokine signaling in bone cancer pain.

    PubMed

    Guo, Genhua; Gao, Feng

    2015-03-01

    Growing evidence indicates that chemokines participate in the generation and maintenance of bone cancer pain (BCP). Recent work in Exp Neurol by Guan et al. (2015) demonstrated the involvement of spinal chemokine receptor CXCR3 and its downstream PI3K/Akt and Raf/MEK/ERK signaling pathways in BCP. This work provides new evidence to support that chemokines participate in central sensitization in BCP condition. Reviewed evidence suggests that few chemokines have been proved to be related to cancer pain. The underlying relationship between CXCR3 signaling and BCP condition requires further study.

  11. Transmembrane chemokines act as receptors in a novel mechanism termed inverse signaling

    PubMed Central

    Hattermann, Kirsten; Gebhardt, Henrike; Krossa, Sebastian; Ludwig, Andreas; Lucius, Ralph

    2016-01-01

    The transmembrane chemokines CX3CL1/fractalkine and CXCL16 are widely expressed in different types of tumors, often without an appropriate expression of their classical receptors. We observed that receptor-negative cancer cells could be stimulated by the soluble chemokines. Searching for alternative receptors we detected that all cells expressing or transfected with transmembrane chemokine ligands bound the soluble chemokines with high affinity and responded by phosphorylation of intracellular kinases, enhanced proliferation and anti-apoptosis. This activity requires the intracellular domain and apparently the dimerization of the transmembrane chemokine ligand. Thus, shed soluble chemokines can generate auto- or paracrine signals by binding and activating their transmembrane forms. We term this novel mechanism “inverse signaling”. We suppose that inverse signaling is an autocrine feedback and fine-tuning system in the communication between cells that in tumors supports stabilization and proliferation. DOI: http://dx.doi.org/10.7554/eLife.10820.001 PMID:26796342

  12. Pathway-selective suppression of chemokine receptor signaling in B cells by LPS through downregulation of PLC-β2.

    PubMed

    Shirakawa, Aiko-Konno; Liao, Fang; Zhang, Hongwei H; Hedrick, Michael N; Singh, Satya P; Wu, Dianqing; Farber, Joshua M

    2010-11-01

    Lymphocyte activation leads to changes in chemokine receptor expression. There are limited data, however, on how lymphocyte activators can alter chemokine signaling by affecting downstream pathways. We hypothesized that B cell-activating agents might alter chemokine responses by affecting downstream signal transducers, and that such effects might differ depending on the activator. We found that activating mouse B cells using either anti-IgM or lipopolysaccharide (LPS) increased the surface expression of CCR6 and CCR7 with large increases in chemotaxis to their cognate ligands. By contrast, while anti-IgM also led to enhanced calcium responses, LPS-treated cells showed only small changes in calcium signaling as compared with cells that were freshly isolated. Of particular interest, we found that LPS caused a reduction in the level of B-cell phospholipase C (PLC)-β2 mRNA and protein. Data obtained using PLC-β2(-/-) mice showed that the β2 isoform mediates close to one-half the chemokine-induced calcium signal in resting and anti-IgM-activated B cells, and we found that calcium signals in the LPS-treated cells were boosted by increasing the level of PLC-β2 using transfection, consistent with a functional effect of downregulating PLC-β2. Together, our results show activator-specific effects on responses through B-cell chemokine receptors that are mediated by quantitative changes in a downstream signal-transducing protein, revealing an activity for LPS as a downregulator of PLC-β2, and a novel mechanism for controlling chemokine-induced signals in lymphocytes.

  13. RGS1 regulates myeloid cell accumulation in atherosclerosis and aortic aneurysm rupture through altered chemokine signalling

    PubMed Central

    Patel, Jyoti; McNeill, Eileen; Douglas, Gillian; Hale, Ashley B.; de Bono, Joseph; Lee, Regent; Iqbal, Asif J.; Regan-Komito, Daniel; Stylianou, Elena; Greaves, David R.; Channon, Keith M.

    2015-01-01

    Chemokine signalling drives monocyte recruitment in atherosclerosis and aortic aneurysms. The mechanisms that lead to retention and accumulation of macrophages in the vascular wall remain unclear. Regulator of G-Protein Signalling-1 (RGS1) deactivates G-protein signalling, reducing the response to sustained chemokine stimulation. Here we show that Rgs1 is upregulated in atherosclerotic plaque and aortic aneurysms. Rgs1 reduces macrophage chemotaxis and desensitizes chemokine receptor signalling. In early atherosclerotic lesions, Rgs1 regulates macrophage accumulation and is required for the formation and rupture of Angiotensin II-induced aortic aneurysms, through effects on leukocyte retention. Collectively, these data reveal a role for Rgs1 in leukocyte trafficking and vascular inflammation and identify Rgs1, and inhibition of chemokine receptor signalling as potential therapeutic targets in vascular disease. PMID:25782711

  14. The CC-Chemokine RANTES Increases the Attachment of Human Immunodeficiency Virus Type 1 to Target Cells via Glycosaminoglycans and Also Activates a Signal Transduction Pathway That Enhances Viral Infectivity

    PubMed Central

    Trkola, Alexandra; Gordon, Cynthia; Matthews, Jamie; Maxwell, Elizabeth; Ketas, Tom; Czaplewski, Lloyd; Proudfoot, Amanda E. I.; Moore, John P.

    1999-01-01

    We have studied the mechanisms by which the CC-chemokine RANTES can enhance the infectivities of human immunodeficiency virus type 1 (HIV-1) and other enveloped viruses, when present at concentrations in excess of 500 ng/ml in vitro. Understanding the underlying mechanisms might throw light on fundamental processes of viral infection, in particular for HIV-1. Our principal findings are twofold: firstly, that oligomers of RANTES can cross-link enveloped viruses, including HIV-1, to cells via glycosaminoglycans (GAGs) present on the membranes of both virions and cells; secondly, that oligomers of RANTES interact with cell-surface GAGs to transduce a herbimycin A-sensitive signal which, over a period of several hours, renders the cells more permissive to infection by several viruses, including HIV-1. The enhancement mechanisms require that RANTES oligomerize either in solution or following binding to GAGs, since no viral infectivity enhancement is observed with a mutant form of the RANTES molecule that contains a single-amino-acid change (glutamic acid to serine at position 66) which abrogates oligomerization. PMID:10400729

  15. Differential Modulation of Retinal Degeneration by Ccl2 and Cx3cr1 Chemokine Signalling

    PubMed Central

    Luhmann, Ulrich F. O.; Lange, Clemens A.; Robbie, Scott; Munro, Peter M. G.; Cowing, Jill A.; Armer, Hannah E. J.; Luong, Vy; Carvalho, Livia S.; MacLaren, Robert E.; Fitzke, Frederick W.; Bainbridge, James W. B.; Ali, Robin R.

    2012-01-01

    Microglia and macrophages are recruited to sites of retinal degeneration where local cytokines and chemokines determine protective or neurotoxic microglia responses. Defining the role of Ccl2-Ccr2 and Cx3cl1-Cx3cr1 signalling for retinal pathology is of particular interest because of its potential role in age-related macular degeneration (AMD). Ccl2, Ccr2, and Cx3cr1 signalling defects impair macrophage trafficking, but have, in several conflicting studies, been reported to show different degrees of age-related retinal degeneration. Ccl2/Cx3cr1 double knockout (CCDKO) mice show an early onset retinal degeneration and have been suggested as a model for AMD. In order to understand phenotypic discrepancies in different chemokine knockout lines and to study how defects in Ccl2 and/or Cx3cr1 signalling contribute to the described early onset retinal degeneration, we defined primary and secondary pathological events in CCDKO mice. To control for genetic background variability, we compared the original phenotype with that of single Ccl2, Cx3cr1 and Ccl2/Cx3cr1 double knockout mice obtained from backcrosses of CCDKO with C57Bl/6 mice. We found that the primary pathological event in CCDKO mice develops in the inferior outer nuclear layer independently of light around postnatal day P14. RPE and vascular lesions develop secondarily with increasing penetrance with age and are clinically similar to retinal telangiectasia not to choroidal neovascularisation. Furthermore, we provide evidence that a third autosomal recessive gene causes the degeneration in CCDKO mice and in all affected re-derived lines and subsequently demonstrated co-segregation of the naturally occurring RD8 mutation in the Crb1 gene. By comparing CCDKO mice with re-derived CCl2−/−/Crb1Rd8/RD8, Cx3cr1−/−/Crb1Rd8/RD8 and CCl2−/−/Cx3cr1−/−/Crb1Rd8/RD8 mice, we observed a differential modulation of the retinal phenotype by genetic background and both chemokine signalling pathways. These findings

  16. Pancreatic cancer cell migration and metastasis is regulated by chemokine-biased agonism and bioenergetic signaling

    PubMed Central

    Roy, Ishan; McAllister, Donna M.; Gorse, Egal; Dixon, Kate; Piper, Clinton T.; Zimmerman, Noah P.; Getschman, Anthony E.; Tsai, Susan; Engle, Dannielle D.; Evans, Douglas B.; Volkman, Brian F.; Kalyanaraman, Balaraman; Dwinell, Michael B.

    2015-01-01

    Patients with pancreatic ductal adenocarcinoma (PDAC) invariably succumb to metastatic disease, but the underlying mechanisms that regulate PDAC cell movement and metastasis remain little understood. In this study, we investigated the effects of the chemokine gene CXCL12, which is silenced in PDAC tumors yet is sufficient to suppress growth and metastasis when re-expressed. Chemokines like CXCL12 regulate cell movement in a biphasic pattern, with peak migration typically in the low nanomolar concentration range. Herein, we tested the hypothesis that the biphasic cell migration pattern induced by CXCL12 reflected a bias of agonist bioenergetic signaling that might be exploited to interfere with PDAC metastasis. In human and murine PDAC cell models, we observed that non-migratory doses of CXCL12 were sufficient to decrease oxidative phosphorylation and glycolytic capacity and to increase levels of phosphorylated forms of the master metabolic kinase AMPK. Those same doses of CXCL12 locked myosin light chain into a phosphorylated state, thereby decreasing F-actin polymerization and preventing cell migration in a manner dependent upon AMPK and the calcium-dependent kinase CAMKII. Notably, at elevated concentrations of CXCL12 that were insufficient to trigger chemotaxis of PDAC cells, AMPK blockade resulted in increased cell movement. In two preclinical mouse models of PDAC, administration of CXCL12 decreased tumor dissemination, supporting our hypothesis that chemokine-biased agonist signaling may offer a useful therapeutic strategy. Our results offer a mechanistic rationale for further investigation of CXCL12 as a potential therapy to prevent or treat PDAC metastasis. PMID:26330165

  17. Chemokine signaling directs trunk lymphatic network formation along the preexisting blood vasculature.

    PubMed

    Cha, Young Ryun; Fujita, Misato; Butler, Matthew; Isogai, Sumio; Kochhan, Eva; Siekmann, Arndt F; Weinstein, Brant M

    2012-04-17

    The lymphatic system is crucial for fluid homeostasis, immune responses, and numerous pathological processes. However, the molecular mechanisms responsible for establishing the anatomical form of the lymphatic vascular network remain largely unknown. Here, we show that chemokine signaling provides critical guidance cues directing early trunk lymphatic network assembly and patterning. The chemokine receptors Cxcr4a and Cxcr4b are expressed in lymphatic endothelium, whereas chemokine ligands Cxcl12a and Cxcl12b are expressed in adjacent tissues along which the developing lymphatics align. Loss- and gain-of-function studies in zebrafish demonstrate that chemokine signaling orchestrates the stepwise assembly of the trunk lymphatic network. In addition to providing evidence for a lymphatic vascular guidance mechanism, these results also suggest a molecular basis for the anatomical coalignment of lymphatic and blood vessels.

  18. Regulation of Chemokine Signal Integration by Activator of G-Protein Signaling 4 (AGS4)

    PubMed Central

    Robichaux, William G.; Branham-O’Connor, Melissa; Hwang, Il-Young; Vural, Ali; Kehrl, Johne H.

    2017-01-01

    Activator of G-protein signaling 4 (AGS4)/G-protein signaling modulator 3 (Gpsm3) contains three G-protein regulatory (GPR) motifs, each of which can bind Gαi-GDP free of Gβγ. We previously demonstrated that the AGS4-Gαi interaction is regulated by seven transmembrane-spanning receptors (7-TMR), which may reflect direct coupling of the GPR-Gαi module to the receptor analogous to canonical Gαβγ heterotrimer. We have demonstrated that the AGS4-Gαi complex is regulated by chemokine receptors in an agonist-dependent manner that is receptor-proximal. As an initial approach to investigate the functional role(s) of this regulated interaction in vivo, we analyzed leukocytes, in which AGS4/Gpsm3 is predominantly expressed, from AGS4/Gpsm3-null mice. Loss of AGS4/Gpsm3 resulted in mild but significant neutropenia and leukocytosis. Dendritic cells, T lymphocytes, and neutrophils from AGS4/Gpsm3-null mice also exhibited significant defects in chemoattractant-directed chemotaxis and extracellular signal-regulated kinase activation. An in vivo peritonitis model revealed a dramatic reduction in the ability of AGS4/Gpsm3-null neutrophils to migrate to primary sites of inflammation. Taken together, these data suggest that AGS4/Gpsm3 is required for proper chemokine signal processing in leukocytes and provide further evidence for the importance of the GPR-Gαi module in the regulation of leukocyte function. PMID:28062526

  19. Epithelial Anion Transport as Modulator of Chemokine Signaling

    PubMed Central

    Schnúr, Andrea; Hegyi, Péter; Rousseau, Simon; Lukacs, Gergely L.; Veit, Guido

    2016-01-01

    The pivotal role of epithelial cells is to secrete and absorb ions and water in order to allow the formation of a luminal fluid compartment that is fundamental for the epithelial function as a barrier against environmental factors. Importantly, epithelial cells also take part in the innate immune system. As a first line of defense they detect pathogens and react by secreting and responding to chemokines and cytokines, thus aggravating immune responses or resolving inflammatory states. Loss of epithelial anion transport is well documented in a variety of diseases including cystic fibrosis, chronic obstructive pulmonary disease, asthma, pancreatitis, and cholestatic liver disease. Here we review the effect of aberrant anion secretion with focus on the release of inflammatory mediators by epithelial cells and discuss putative mechanisms linking these transport defects to the augmented epithelial release of chemokines and cytokines. These mechanisms may contribute to the excessive and persistent inflammation in many respiratory and gastrointestinal diseases. PMID:27382190

  20. Signal transmission through the CXC chemokine receptor 4 (CXCR4) transmembrane helices

    PubMed Central

    Wescott, Melanie P.; Kufareva, Irina; Paes, Cheryl; Goodman, Jason R.; Thaker, Yana; Puffer, Bridget A.; Berdougo, Eli; Rucker, Joseph B.; Handel, Tracy M.; Doranz, Benjamin J.

    2016-01-01

    The atomic-level mechanisms by which G protein-coupled receptors (GPCRs) transmit extracellular ligand binding events through their transmembrane helices to activate intracellular G proteins remain unclear. Using a comprehensive library of mutations covering all 352 residues of the GPCR CXC chemokine receptor 4 (CXCR4), we identified 41 amino acids that are required for signaling induced by the chemokine ligand CXCL12 (stromal cell-derived factor 1). CXCR4 variants with each of these mutations do not signal properly but remain folded, based on receptor surface trafficking, reactivity to conformationally sensitive monoclonal antibodies, and ligand binding. When visualized on the structure of CXCR4, the majority of these residues form a continuous intramolecular signaling chain through the transmembrane helices; this chain connects chemokine binding residues on the extracellular side of CXCR4 to G protein-coupling residues on its intracellular side. Integrated into a cohesive model of signal transmission, these CXCR4 residues cluster into five functional groups that mediate (i) chemokine engagement, (ii) signal initiation, (iii) signal propagation, (iv) microswitch activation, and (v) G protein coupling. Propagation of the signal passes through a “hydrophobic bridge” on helix VI that coordinates with nearly every known GPCR signaling motif. Our results agree with known conserved mechanisms of GPCR activation and significantly expand on understanding the structural principles of CXCR4 signaling. PMID:27543332

  1. Biased agonism as a mechanism for differential signaling by chemokine receptors.

    PubMed

    Rajagopal, Sudarshan; Bassoni, Daniel L; Campbell, James J; Gerard, Norma P; Gerard, Craig; Wehrman, Tom S

    2013-12-06

    Chemokines display considerable promiscuity with multiple ligands and receptors shared in common, a phenomenon that is thought to underlie their biochemical "redundancy." Their receptors are part of a larger seven-transmembrane receptor superfamily, commonly referred to as G protein-coupled receptors, which have been demonstrated to be able to signal with different efficacies to their multiple downstream signaling pathways, a phenomenon referred to as biased agonism. Biased agonism has been primarily reported as a phenomenon of synthetic ligands, and the biologic prevalence and importance of such signaling are unclear. Here, to assess the presence of biased agonism that may underlie differential signaling by chemokines targeting the same receptor, we performed a detailed pharmacologic analysis of a set of chemokine receptors with multiple endogenous ligands using assays for G protein signaling, β-arrestin recruitment, and receptor internalization. We found that chemokines targeting the same receptor can display marked differences in their efficacies for G protein- or β-arrestin-mediated signaling or receptor internalization. This ligand bias correlates with changes in leukocyte migration, consistent with different mechanisms underlying the signaling downstream of these receptors induced by their ligands. These findings demonstrate that biased agonism is a common and likely evolutionarily conserved biological mechanism for generating qualitatively distinct patterns of signaling via the same receptor in response to different endogenous ligands.

  2. Neuronal apoptotic signaling pathways probed and intervened by synthetically and modularly modified (SMM) chemokines.

    PubMed

    Choi, Won-Tak; Kaul, Marcus; Kumar, Santosh; Wang, Jun; Kumar, I M Krishna; Dong, Chang-Zhi; An, Jing; Lipton, Stuart A; Huang, Ziwei

    2007-03-09

    As the main coreceptors for human immunodeficiency virus type 1 (HIV-1) entry, CXCR4 and CCR5 play important roles in HIV-associated dementia (HAD). HIV-1 glycoprotein gp120 contributes to HAD by causing neuronal damage and death, either directly by triggering apoptotic pathways or indirectly by stimulating glial cells to release neurotoxins. Here, to understand the mechanism of CXCR4 or CCR5 signaling in neuronal apoptosis associated with HAD, we have applied synthetically and modularly modified (SMM)-chemokine analogs derived from natural stromal cell-derived factor-1alpha or viral macrophage inflammatory protein-II as chemical probes of the mechanism(s) whereby these SMM-chemokines prevent or promote neuronal apoptosis. We show that inherently neurotoxic natural ligands of CXCR4, such as stromal cell-derived factor-1alpha or viral macrophage inflammatory protein-II, can be modified to protect neurons from apoptosis induced by CXCR4-preferring gp120(IIIB), and that the inhibition of CCR5 by antagonist SMM-chemokines, unlike neuroprotective CCR5 natural ligands, leads to neurotoxicity by activating a p38 mitogen-activated protein kinase (MAPK)-dependent pathway. Furthermore, we discover distinct signaling pathways activated by different chemokine ligands that are either natural agonists or synthetic antagonists, thus demonstrating a chemical biology strategy of using chemically engineered inhibitors of chemokine receptors to study the signaling mechanism of neuronal apoptosis and survival.

  3. A20 regulates IL-1-induced tolerant production of CXC chemokines in human mesangial cells via inhibition of MAPK signaling

    PubMed Central

    Luo, Hongbo; Liu, Yuming; Li, Qian; Liao, Lingjuan; Sun, Ruili; Liu, Xueting; Jiang, Manli; Hu, Jinyue

    2015-01-01

    Chemokines and chemokine receptors are involved in the resolution or progression of renal diseases. Locally secreted chemokines mediated leukocyte recruitment during the initiation and amplification phase of renal inflammation. However, the regulation of chemokine induction is not fully understood. In this study, we found that IL-1 induced a significant up-regulation of CXC chemokines CXCL1, 2, and 8 at both mRNA and protein levels in human mesangial cells. The induction of chemokines was tolerant, as the pre-treatment of HMC with IL-1 down-regulated the induction of chemokines induced by IL-1 re-stimulation. IL-1 up-regulated the ubiquintin-editing enzyme A20. A20 over-expression down-regulated IL-1-induced up-regulation of chemokines, and A20 down-regulation reversed chemokine inhibition induced by IL-1 pre-treatment, suggested that A20 played important roles in the tolerant production of chemokines. Unexpectedly, A20 over- expression inhibited the activation of ERK, JNK, and P38, but did not inhibit the activation of NF-κB. In addition, both IL-1 treatment and A20 over-expression induced the degradation of IRAK1, an important adaptor for IL-1R1 signaling, and A20 inhibition by RNA interference partly reversed the degradation of IRAK1. Taken together, IL-1-induced A20 negatively regulated chemokine production, suggesting that A20 may be an important target for the prevention and control of kidney inflammation. PMID:26648169

  4. Induction of cytokines and chemokines by Toll-like receptor signaling: strategies for control of inflammation.

    PubMed

    Zeytun, Ahmet; Chaudhary, Anu; Pardington, Paige; Cary, R; Gupta, Goutam

    2010-01-01

    Recognition of the pathogen-associated molecular pattern (PAMP) by host Toll-like receptors (TLR) is an important component of the innate immune response for countering against invading viruses, bacteria, and fungi. Upon PAMP recognition, the TLR induces intracellular signaling cascades that involve adapter, signalosome, and transcription factor complexes and result in the production of both pro- and anti-inflammatory cytokines and chemokines. An inflammatory response for a short duration can be beneficial because it helps to clear the infectious agent. However, prolonged inflammation can be detrimental because it may cause host toxicity and tissue damage. Indeed, excessive production of inflammatory cytokines and chemokines via TLR pathways is often associated with many inflammatory and autoimmune diseases. Therefore, fine control of inflammation in the TLR pathway is highly desirable for effective host defense. In this article, we review intrinsic control mechanisms that include a balance between pro-inflammatory and anti-inflammatory cytokines and chemokines, production of host effectors, and regulation at the level of adapter, signalosome, and transcription factor complexes in the TLR pathways. We also discuss how understanding of the TLR signaling steps leads to the development of small-molecule drugs that can interfere with the formation of active adapter, signalosome, and adapter complexes.

  5. CXCR3 chemokine receptor signaling mediates itch in experimental allergic contact dermatitis.

    PubMed

    Qu, Lintao; Fu, Kai; Yang, Jennifer; Shimada, Steven G; LaMotte, Robert H

    2015-09-01

    Persistent itch is a common symptom of allergic contact dermatitis (ACD) and represents a significant health burden. The chemokine CXCL10 is predominantly produced by epithelial cells during ACD. Although the chemokine CXCL10 and its receptor CXCR3 are implicated in the pathophysiology of ACD, it is largely unexplored for itch and pain accompanying this disorder. Here, we showed that CXCL10 and CXCR3 mRNA, protein, and signaling activity were upregulated in the dorsal root ganglion after contact hypersensitivity (CHS), a murine model of ACD, induced by squaric acid dibutylester. CXCL10 directly activated a subset of cutaneous dorsal root ganglion neurons innervating the area of CHS through neuronal CXCR3. In behavioral tests, a CXCR3 antagonist attenuated spontaneous itch- but not pain-like behaviors directed to the site of CHS. Injection of CXCL10 into the site of CHS elicited site-directed itch- but not pain-like behaviors, but neither type of CXCL10-evoked behaviors was observed in control mice. These results suggest that CXCL10/CXCR3 signaling mediates allergic itch but not inflammatory pain in the context of skin inflammation. Thus, upregulation of CXCL10/CXCR3 signaling in sensory neurons may contribute to itch associated with ACD. Targeting the CXCL10/CXCR3 signaling might be beneficial for the treatment of allergic itch.

  6. Induction of chemokine (C-C motif) ligand 2 by sphingosine-1-phosphate signaling in neuroblastoma

    PubMed Central

    Li, Mei-Hong; Harel, Miriam; Hla, Timothy; Ferrer, Fernando

    2014-01-01

    Background/Purpose Neuroblastoma (NB) is the most common extracranial solid tumor of childhood. Preliminary data derived from a human angiogenesis array in NB showed that the bioactive lipid sphingosine-1-phosphate (S1P) induced the secretion of several angiogenesis-related proteins including the important inflammatory factor chemokine (C-C motif) ligand 2 (CCL2). In the present study, we investigated the mechanism of S1P-induced CCL2 expression in NB. Methods Quantitative real-time PCR and CCL2 ELISA were conducted to detect the mRNA expression and protein secretion of CCL2 in NB cells. Gain and loss of function studies were performed by using specific S1PR antagonists, adenoviral transduction and siRNA transfection. Macrophage F4/80 receptor in NB xenografts was detected by quantitative real-time PCR and immunohistochemistry staining. Results S1P induced CCL2 mRNA expression and protein secretion in a time- and concentration-dependent manner in NB cells. Blockade of S1P2 signaling using the selective S1P2 antagonist JTE-013 inhibited S1P-induced CCL2 expression. Overexpression of S1P2 by adenoviral transduction increased CCL2 secretion while knockdown of S1P2 by siRNA transfection decreased S1P-induced CCL2 secretion in NB cells. Macrophage infiltration, as detected by F4/80 staining, was significantly decreased in JTE-013-treated NB xenografts. Conclusions Taken together, our data for the first time demonstrate that S1P induced the macrophage-recruiting factor CCL2 expression in NB cells via S1P2, providing new insights into the complicated functions of S1P2 in cancer. PMID:25092091

  7. Increased plasma chemokine levels in children with Prader-Willi syndrome.

    PubMed

    Butler, Merlin G; Hossain, Waheeda; Sulsona, Carlos; Driscoll, Daniel J; Manzardo, Ann M

    2015-03-01

    Prader-Willi syndrome (PWS) is caused by loss of paternally expressed genes from the 15q11-q13 region and reportedly rearranged as a cause of autism. Additionally, increased inflammatory markers and features of autism are reported in PWS. Cytokines encoded by genes involved with inflammation, cell proliferation, migration, and adhesion play a role in neurodevelopment and could be disturbed in PWS as abnormal plasma cytokine levels are reported in autism. We analyzed 41 plasma cytokines in a cohort of well-characterized children with PWS between 5 and 11 years of age and unaffected unrelated siblings using multiplex sandwich immunoassays with the Luminex magnetic-bead based platform. Data were analyzed using ANOVA testing for effects of diagnosis, gender, body mass index (BMI) and age on the 24 cytokines meeting laboratory criteria for inclusion. No significant effects were observed for age, gender or BMI. The log-transformed levels of the 24 analyzable cytokines were examined simultaneously using MANOVA adjusting for age and gender and a main effect of diagnosis was found (P-value <0.03). Four of 24 plasma cytokine levels (MCP1, MDC, Eotaxin, RANTES) were significantly higher in children with PWS compared with controls and classified as bioinflammatory chemokines supporting a disturbed immune response unrelated to obesity status. BMI was not statistically different in the two subject groups (PWS or unaffected unrelated siblings) and chemokine levels were not correlated with percentage of total body fat. Additional studies are required to identify whether possible early immunological disturbances and chemokine inflammatory processes found in PWS may contribute to neurodevelopment and behavioral features.

  8. Fas/CD95-induced chemokines can serve as "find-me" signals for apoptotic cells.

    PubMed

    Cullen, Sean P; Henry, Conor M; Kearney, Conor J; Logue, Susan E; Feoktistova, Maria; Tynan, Graham A; Lavelle, Ed C; Leverkus, Martin; Martin, Seamus J

    2013-03-28

    Apoptosis is commonly thought to represent an immunologically silent or even anti-inflammatory mode of cell death, resulting in cell clearance in the absence of explicit activation of the immune system. However, here we show that Fas/CD95-induced apoptosis is associated with the production of an array of cytokines and chemokines, including IL-6, IL-8, CXCL1, MCP-1, and GMCSF. Fas-induced production of MCP-1 and IL-8 promoted chemotaxis of phagocytes toward apoptotic cells, suggesting that these factors serve as "find-me" signals in this context. We also show that RIPK1 and IAPs are required for optimal production of cytokines and chemokines in response to Fas receptor stimulation. Consequently, a synthetic IAP antagonist potently suppressed Fas-dependent expression of multiple proinflammatory mediators and inhibited Fas-induced chemotaxis. Thus, in addition to provoking apoptosis, Fas receptor stimulation can trigger the secretion of chemotactic factors and other immunologically active proteins that can influence immune responsiveness toward dying cells.

  9. Vesicular Trafficking and Signaling for Cytokine and Chemokine Secretion in Mast Cells

    PubMed Central

    Blank, Ulrich; Madera-Salcedo, Iris Karina; Danelli, Luca; Claver, Julien; Tiwari, Neeraj; Sánchez-Miranda, Elizabeth; Vázquez-Victorio, Genaro; Ramírez-Valadez, Karla Alina; Macias-Silva, Marina; González-Espinosa, Claudia

    2014-01-01

    Upon activation mast cells (MCs) secrete numerous inflammatory compounds stored in their cytoplasmic secretory granules by a process called anaphylactic degranulation, which is responsible for type I hypersensitivity responses. Prestored mediators include histamine and MC proteases but also some cytokines and growth factors making them available within minutes for a maximal biological effect. Degranulation is followed by the de novo synthesis of lipid mediators such as prostaglandins and leukotrienes as well as a vast array of cytokines, chemokines, and growth factors, which are responsible for late phase inflammatory responses. While lipid mediators diffuse freely out of the cell through lipid bilayers, both anaphylactic degranulation and secretion of cytokines, chemokines, and growth factors depends on highly regulated vesicular trafficking steps that occur along the secretory pathway starting with the translocation of proteins to the endoplasmic reticulum. Vesicular trafficking in MCs also intersects with endocytic routes, notably to form specialized cytoplasmic granules called secretory lysosomes. Some of the mediators like histamine reach granules via specific vesicular monoamine transporters directly from the cytoplasm. In this review, we try to summarize the available data on granule biogenesis and signaling events that coordinate the complex steps that lead to the release of the inflammatory mediators from the various vesicular carriers in MCs. PMID:25295038

  10. Increased cytokine/chemokines in serum from asthmatic and non-asthmatic patients with viral respiratory infection

    PubMed Central

    Giuffrida, María J; Valero, Nereida; Mosquera, Jesús; Alvarez de Mon, Melchor; Chacín, Betulio; Espina, Luz Marina; Gotera, Jennifer; Bermudez, John; Mavarez, Alibeth

    2014-01-01

    Background Respiratory viral infections can induce different cytokine/chemokine profiles in lung tissues and have a significant influence on patients with asthma. There is little information about the systemic cytokine status in viral respiratory-infected asthmatic patients compared with non-asthmatic patients. Objectives The aim of this study was to determine changes in circulating cytokines (IL-1β, TNF-α, IL-4, IL-5) and chemokines (MCP1: monocyte chemoattractant protein-1 and RANTES: regulated on activation normal T cell expressed and secreted) in patients with an asthmatic versus a non-asthmatic background with respiratory syncytial virus, parainfluenza virus or adenovirus respiratory infection. In addition, human monocyte cultures were incubated with respiratory viruses to determine the cytokine/chemokine profiles. Patients/Methods Patients with asthmatic (n = 34) and non-asthmatic (n = 18) history and respiratory infections with respiratory syncytial virus, parainfluenza, and adenovirus were studied. Healthy individuals with similar age and sex (n = 10) were used as controls. Cytokine/chemokine content in blood and culture supernatants was determined by ELISA. Monocytes were isolated by Hystopaque gradient and cocultured with each of the above-mentioned viruses. Results Similar increased cytokine concentrations were observed in asthmatic and non-asthmatic patients. However, higher concentrations of chemokines were observed in asthmatic patients. Virus-infected monocyte cultures showed similar cytokine/chemokine profiles to those observed in the patients. Conclusions Circulating cytokine profiles induced by acute viral lung infection were not related to asthmatic status, except for chemokines that were already increased in the asthmatic status. Monocytes could play an important role in the increased circulating concentration of cytokines found during respiratory viral infections. PMID:23962134

  11. Chemokines and BPH/LUTS.

    PubMed

    Macoska, Jill A

    2011-01-01

    A wealth of published studies indicate that a variety of chemokines are actively secreted by the prostatic microenvironment consequent to disruptions in normal tissue homeostasis due to the aging process or inflammatory responses. The accumulation of senescent stromal fibroblasts, and, possibly, epithelial cells, may serve as potential driving forces behind chemokine secretion in the aging and enlarged human prostate. Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) and histological inflammation may also potentially serve as rich sources of chemokine secretion in the prostate. Once bound to their cognate receptors, chemokines can stimulate powerful pro-proliferation signal transduction pathways and thus function as potent growth factors in the development and progression of Benign Prostatic Hyperplasia (BPH) and lower urinary tract symptoms (LUTS). These functions have been amply demonstrated experimentally and particularly point to robust Mitogen Activated Protein Kinase (MAPK) and phosphoinositide 3-kinase (PI3K) signaling, as well as global transcriptional responses, which mediate chemokine-stimulated cellular proliferative responses. A small body of literature also suggests that chemokine-mediated angiogenesis may comprise a contributing factor to BPH/LUTS development and progression. Thus, the observed low-level secretion of multiple chemokines within the aging prostatic microenvironment may promote a concomitant low-level, but cumulative, over-proliferation of both stromal fibroblastic and epithelial cell types associated with increased prostatic volume. Though the accumulated evidence is far from complete and suffers from some rather extensive gaps in knowledge, it argues favorably for the conclusion that chemokines can, and likely do, promote prostatic enlargement and the associated lower urinary tract symptoms, and justifies further investigations examining chemokines as potential therapeutic targets to delay or ablate BPH/LUTS initiation and

  12. Increasing the efficacy of radiotherapy by modulating the CCR2/CCR5 chemokine axes

    PubMed Central

    Connolly, Kelli A.; Belt, Brian A.; Figueroa, Nathania M.; Murthy, Aditi; Patel, Ankit; Kim, Minsoo; Lord, Edith M.; Linehan, David C.; Gerber, Scott A.

    2016-01-01

    Although radiotherapy (RT) is widely used to control tumor growth across many cancer types, there is a relatively high incidence of RT failure exhibited by tumor recurrence, therefore a clear need exists to achieve improved effectiveness of RT. The RT-elicited immune response largely impacts the efficacy of RT and includes immune cells that kill tumor cells, but also immunosuppressive cells, which dampen anti-tumor immunity. Using murine models in which syngeneic tumor cell lines (Colon38, Glioma261, Line1) are grown intramuscularly and treated with 15 Gy local RT, we assessed the effects of RT on both the systemic and intratumoral immune response. Here we demonstrate that RT stimulates increased production of two chemokines, CCL2 and CCL5, at the tumor site. Further, that this leads to increased CCR2+ CCR5+ monocytes in circulation and subsequently alters the intratumoral immune infiltrate favoring the largely immunosuppressive CCR2+ CCR5+ monocytes. Importantly, a CCR2/CCR5 antagonist administered daily (15 mg/kg subcutaneously) starting two days prior to RT reduces both circulating and intratumoral monocytes resulting in increased efficacy of RT in radioresponsive tumors. Overall, these data have important implications for the mechanism of RT and present a means to improve RT efficacy across many cancer types. PMID:27852031

  13. Intermediate Progenitors Facilitate Intracortical Progression of Thalamocortical Axons and Interneurons through CXCL12 Chemokine Signaling.

    PubMed

    Abe, Philipp; Molnár, Zoltán; Tzeng, Yi-Shiuan; Lai, Dar-Ming; Arnold, Sebastian J; Stumm, Ralf

    2015-09-23

    Glutamatergic principal neurons, GABAergic interneurons and thalamocortical axons (TCAs) are essential elements of the cerebrocortical network. Principal neurons originate locally from radial glia and intermediate progenitors (IPCs), whereas interneurons and TCAs are of extrinsic origin. Little is known how the assembly of these elements is coordinated. C-X-C motif chemokine 12 (CXCL12), which is known to guide axons outside the neural tube and interneurons in the cortex, is expressed in the meninges and IPCs. Using mouse genetics, we dissected the influence of IPC-derived CXCL12 on TCAs and interneurons by showing that Cxcl12 ablation in IPCs, leaving meningeal Cxcl12 intact, attenuates intracortical TCA growth and disrupts tangential interneuron migration in the subventricular zone. In accordance with strong CXCR4 expression in the forming thalamus and TCAs, we identified a CXCR4-dependent growth-promoting effect of CXCL12 on TCAs in thalamus explants. Together, our findings indicate a cell-autonomous role of CXCR4 in promoting TCA growth. We propose that CXCL12 signals from IPCs link cortical neurogenesis to the progression of TCAs and interneurons spatially and temporally. Significance statement: The cerebral cortex exerts higher brain functions including perceptual and emotional processing. Evolutionary expansion of the mammalian cortex is mediated by intermediate progenitors, transient amplifying cells generating cortical excitatory neurons. During the peak period of cortical neurogenesis, migrating precursors of inhibitory interneurons originating in subcortical areas and thalamic axons invade the cortex. Although defects in the assembly of cortical network elements cause neurological and mental disorders, little is known how neurogenesis, interneuron recruitment, and axonal ingrowth are coordinated. We demonstrate that intermediate progenitors release the chemotactic cytokine CXCL12 to promote intracortical interneuron migration and growth of thalamic axons

  14. Cxcl12/Cxcr4 chemokine signaling is required for placode assembly and sensory axon pathfinding in the zebrafish olfactory system.

    PubMed

    Miyasaka, Nobuhiko; Knaut, Holger; Yoshihara, Yoshihiro

    2007-07-01

    Positioning neurons in the right places and wiring axons to the appropriate targets are essential events for establishment of neural circuits. In the zebrafish olfactory system, precursors of olfactory sensory neurons (OSNs) assemble into a compact cluster to form the olfactory placode. Subsequently, OSNs differentiate and extend their axons to the presumptive olfactory bulb with high precision. In this study, we aim to elucidate the molecular mechanism underlying these two developmental processes. cxcr4b, encoding a chemokine receptor, is expressed in the migrating olfactory placodal precursors, and cxcl12a (SDF-1a), encoding a ligand for Cxcr4b, is expressed in the abutting anterior neural plate. The expression of cxcr4b persists in the olfactory placode at the initial phase of OSN axon pathfinding. At this time, cxcl12a is expressed along the placode-telencephalon border and at the anterior tip of the telencephalon, prefiguring the route and target of OSN axons, respectively. Interfering with Cxcl12a/Cxcr4b signaling perturbs the assembly of the olfactory placode, resulting in the appearance of ventrally displaced olfactory neurons. Moreover, OSN axons frequently fail to exit the olfactory placode and accumulate near the placode-telencephalon border in the absence of Cxcr4b-mediated signaling. These data indicate that chemokine signaling contributes to both the olfactory placode assembly and the OSN axon pathfinding in zebrafish.

  15. Chemokines in cancer.

    PubMed

    Chow, Melvyn T; Luster, Andrew D

    2014-12-01

    Chemokines are chemotactic cytokines that control the migration of cells between tissues and the positioning and interactions of cells within tissue. The chemokine superfamily consists of approximately 50 endogenous chemokine ligands and 20 G protein-coupled seven-transmembrane spanning signaling receptors. Chemokines mediate the host response to cancer by directing the trafficking of leukocytes into the tumor microenvironment. This migratory response is complex and consists of diverse leukocyte subsets with both antitumor and protumor activities. Although chemokines were initially appreciated as important mediators of immune cell migration, we now know that they also play important roles in the biology of nonimmune cells important for tumor growth and progression. Chemokines can directly modulate the growth of tumors by inducing the proliferation of cancer cells and preventing their apoptosis. They also direct tumor cell movement required for metastasis. Chemokines can also indirectly modulate tumor growth through their effects on tumor stromal cells and by inducing the release of growth and angiogenic factors from cells in the tumor microenvironment. In this Masters of Immunology primer, we focus on recent advances in understanding the complex nature of the chemokine system in tumor biology with a focus on how the chemokine system could be used to augment cancer immunotherapeutic strategies to elicit a more robust and long-lasting host antitumor immune response.

  16. Articular Ankle Fracture Results in Increased Synovitis, Synovial Macrophage Infiltration, and Synovial Fluid Concentrations of Inflammatory Cytokines and Chemokines

    PubMed Central

    Furman, Bridgette D.; Kimmerling, Kelly A.; Zura, Robert D.; Reilly, Rachel M.; Zlowodzki, Michal P.; Huebner, Janet L.; Kraus, Virginia B.; Guilak, Farshid; Olson, Steven A.

    2016-01-01

    Objective The inflammatory response following an articular fracture is thought to play a role in the development of posttraumatic arthritis (PTA) but has not been well characterized. The objective of this study was to characterize the acute inflammatory response, both locally and systemically, in joint synovium, synovial fluid (SF), and serum following articular fracture of the ankle. We hypothesized that intraarticular fracture would alter the synovial environment and lead to increased local and systemic inflammation. Methods Synovial tissue biopsy specimens, SF samples, and serum samples were collected from patients with an acute articular ankle fracture (n = 6). Additional samples (normal, ankle osteoarthritis [OA], and knee OA [n = 6 per group]) were included for comparative analyses. Synovial tissue was assessed for synovitis and macrophage count. SF and serum were assessed for cytokines (interferon-γ [IFNγ], interleukin-1β [IL-1β], IL-6, IL-8, IL-10, IL-12p70, and tumor necrosis factor α) and chemokines (eotaxin, eotaxin 3, IFNγ-inducible 10-kd protein, monocyte chemotactic protein 1 [MCP-1], MCP-4, macrophage-derived chemokine, macrophage inflammatory protein 1β, and thymus and activation–regulated chemokine). Results Synovitis scores were significantly higher in ankle fracture tissue compared with normal ankle tissue (P = 0.007), and there was a trend toward an increased abundance of CD68+ macrophages in ankle fracture synovium compared with normal knee synovium (P = 0.06). The concentrations of all cytokines and chemokines were elevated in the SF of patients with ankle fracture compared with those in SF from OA patients with no history of trauma. Only the concentration of IL-6 was significantly increased in the serum of patients with ankle fracture compared with normal serum (P = 0.027). Conclusion Articular fracture of the ankle increased acute local inflammation, as indicated by increased synovitis, increased macrophage infiltration into

  17. A Hox gene controls lateral line cell migration by regulating chemokine receptor expression downstream of Wnt signaling.

    PubMed

    Breau, Marie A; Wilkinson, David G; Xu, Qiling

    2013-10-15

    The posterior lateral line primordium in zebrafish provides an amenable model to study mechanisms of collective cell migration. The directed migration of the cell cluster along the path of Sdf1a chemokine requires two receptors, Cxcr4b and Cxcr7b, which are expressed in the leading and trailing part of the primordium, respectively. The polarized expression of receptors is regulated by Wnt signaling, but downstream players mediating this control remain to be found. Here, we show that the Hox homeobox gene Hoxb8a is a critical component that acts downstream of the Wnt pathway to coordinate the expression of both chemokine receptors. We find that Hoxb8a is expressed in the leading part of the primordium and is required for the correct speed and extent of migration. Hoxb8a expression is dependent upon Wnt activity and needed both for cxcr4b expression and to repress and thus restrict cxcr7b expression to the trailing zone of the primordium. In the absence of Wnt activity, overexpressed Hoxb8a is able to repress cxcr7b but not up-regulate cxcr4b expression. Together with results from expressing dominant activator and repressor constructs, these findings suggest that Hoxb8a is induced by and cooperates with Wnt signaling to up-regulate cxcr4b, and acts through multiple mechanisms to repress cxcr7b expression.

  18. Partial Agonist and Biased Signaling Properties of the Synthetic Enantiomers J113863/UCB35625 at Chemokine Receptors CCR2 and CCR5.

    PubMed

    Corbisier, Jenny; Huszagh, Alexandre; Galés, Céline; Parmentier, Marc; Springael, Jean-Yves

    2017-01-13

    Biased agonism at G protein-coupled receptors constitutes a promising area of research for the identification of new therapeutic molecules. In this study we identified two novel biased ligands for the chemokine receptors CCR2 and CCR5 and characterized their functional properties. We showed that J113863 and its enantiomer UCB35625, initially identified as high affinity antagonists for CCR1 and CCR3, also bind with low affinity to the closely related receptors CCR2 and CCR5. Binding of J113863 and UCB35625 to CCR2 or CCR5 resulted in the full or partial activation of the three Gi proteins and the two Go isoforms. Unlike chemokines, the compounds did not activate G12 Binding of J113863 to CCR2 or CCR5 also induced the recruitment of β-arrestin 2, whereas UCB35625 did not. UCB35625 induced the chemotaxis of L1.2 cells expressing CCR2 or CCR5. In contrast, J113863 induced the migration of L1.2-CCR2 cells but antagonized the chemokine-induced migration of L1.2-CCR5 cells. We also showed that replacing the phenylalanine 3.33 in CCR5 TM3 by the corresponding histidine of CCR2 converts J113863 from an antagonist for cell migration and a partial agonist in other assays to a full agonist in all assays. Further analyses indicated that F3.33H substitution strongly increased the activation of G proteins and β-arrestin 2 by J113863. These results highlight the biased nature of the J113863 and UCB35625 that act either as antagonist, partial agonist, or full agonist according to the receptor, the enantiomer, and the signaling pathway investigated.

  19. [Research progress on role of chemokine receptor CCR3 signaling in allergic airway diseases].

    PubMed

    Xu, Yi; Liu, Yuehui

    2012-12-01

    Allergic airway diseases have been identified as chronic inflammatory diseases of respiratory membranes, characterized by infiltration of many inflammatory cells, especially eosinophils. The expression of CCR3 is abundant on the cell surface of eosinophils. Increased accumulation of CCR3-driven inflammatory cells is thought to favor the development of allergy. In this review, we survey the properties of CCR3 and its ligands and highlight the roles of CCR3 signaling in allergic airway diseases.

  20. The chemokine CCL5 regulates glucose uptake and AMP kinase signaling in activated T cells to facilitate chemotaxis.

    PubMed

    Chan, Olivia; Burke, J Daniel; Gao, Darrin F; Fish, Eleanor N

    2012-08-24

    Recruitment of effector T cells to sites of infection or inflammation is essential for an effective adaptive immune response. The chemokine CCL5 (RANTES) activates its cognate receptor, CCR5, to initiate cellular functions, including chemotaxis. In earlier studies, we reported that CCL5-induced CCR5 signaling activates the mTOR/4E-BP1 pathway to directly modulate mRNA translation. Specifically, CCL5-mediated mTOR activation contributes to T cell chemotaxis by initiating the synthesis of chemotaxis-related proteins. Up-regulation of chemotaxis-related proteins may prime T cells for efficient migration. It is now clear that mTOR is also a central regulator of nutrient sensing and glycolysis. Herein we describe a role for CCL5-mediated glucose uptake and ATP accumulation to meet the energy demands of chemotaxis in activated T cells. We provide evidence that CCL5 is able to induce glucose uptake in an mTOR-dependent manner. CCL5 treatment of ex vivo activated human CD3(+) T cells also induced the activation of the nutrient-sensing kinase AMPK and downstream substrates ACC-1, PFKFB-2, and GSK-3β. Using 2-deoxy-d-glucose, an inhibitor of glucose uptake, and compound C, an inhibitor of AMPK, experimental data are presented that demonstrate that CCL5-mediated T cell chemotaxis is dependent on glucose, as these inhibitors inhibit CCL5-mediated chemotaxis in a dose-dependent manner. Altogether, these findings suggest that both glycolysis and AMPK signaling are required for efficient T cell migration in response to CCL5. These studies extend the role of CCL5 mediated CCR5 signaling beyond lymphocyte chemotaxis and demonstrate a role for chemokines in promoting glucose uptake and ATP production to match energy demands of migration.

  1. Chemokines as relay signals in human dendritic cell migration: serum amyloid A kicks off chemotaxis.

    PubMed

    Sozzani, Silvano; Del Prete, Annalisa

    2015-01-01

    Cell migration is a response highly conserved in evolution. Chemotactic factors secreted in injured and inflamed tissues generate a concentration-based, chemotactic gradient that directs leukocytes from the blood compartment into tissue. In this issue of the European Journal of Immunology, Gouwy et al. [Eur. J. Immunol. 2015. 45: 101-112] show that the SAA1α isoform of serum amyloid A (SAA), which is an acute phase protein upregulated in inflammation and shown to chemoattract some leukocyte subsets, is also able to chemoattract monocyte-derived immature dendritic cells (DCs). The authors also show that the chemotactic activity of SAA1α for monocytes and DCs is indirectly mediated by rapid chemokine induction, providing evidence that proposes a new level of regulation of leukocyte migration.

  2. Chemically induced neuronal damage and gliosis: enhanced expression of the proinflammatory chemokine, monocyte chemoattractant protein (MCP)-1, without a corresponding increase in proinflammatory cytokines(1).

    PubMed

    Little, A R; Benkovic, S A; Miller, D B; O'Callaghan, J P

    2002-01-01

    Enhanced expression of proinflammatory cytokines and chemokines has long been linked to neuronal and glial responses to brain injury. Indeed, inflammation in the brain has been associated with damage that stems from conditions as diverse as infection, multiple sclerosis, trauma, and excitotoxicity. In many of these brain injuries, disruption of the blood-brain barrier (BBB) may allow entry of blood-borne factors that contribute to, or serve as the basis of, brain inflammatory responses. Administration of trimethyltin (TMT) to the rat results in loss of hippocampal neurons and an ensuing gliosis without BBB compromise. We used the TMT damage model to discover the proinflammatory cytokines and chemokines that are expressed in response to neuronal injury. TMT caused pyramidal cell damage within 3 days and a substantial loss of these neurons by 21 days post dosing. Marked microglial activation and astrogliosis were evident over the same time period. The BBB remained intact despite the presence of multiple indicators of TMT-induced neuropathology. TMT caused large increases in whole hippocampal-derived monocyte chemoattractant protein (MCP)-1 mRNA (1,000%) by day 3 and in MCP-1 (300%) by day 7. The mRNA levels for tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta and IL-6, cytokines normally expressed during the earliest stage of inflammation, were not increased up to 21 days post dosing. Lipopolysaccharide, used as a positive control, caused large inductions of cytokine mRNA in liver, as well as an increase in IL-1beta in hippocampus, but it did not result in the induction of astrogliosis. The data suggest that enhanced expression of the proinflammatory cytokines, TNF-alpha, IL-1beta and IL-6, is not required for neuronal and glial responses to injury and that MCP-1 may serve a signaling function in the damaged CNS that is distinct from its role in proinflammatory events.

  3. Common and biased signaling pathways of the chemokine receptor CCR7 elicited by its ligands CCL19 and CCL21 in leukocytes.

    PubMed

    Hauser, Mark A; Legler, Daniel F

    2016-06-01

    Chemokines are pivotal regulators of cell migration during continuous immune surveillance, inflammation, homeostasis, and development. Chemokine binding to their 7-transmembrane domain, G-protein-coupled receptors causes conformational changes that elicit intracellular signaling pathways to acquire and maintain an asymmetric architectural organization and a polarized distribution of signaling molecules necessary for directional cell migration. Leukocytes rely on the interplay of chemokine-triggered migration modules to promote amoeboid-like locomotion. One of the most important chemokine receptors for adaptive immune cell migration is the CC-chemokine receptor CCR7. CCR7 and its ligands CCL19 and CCL21 control homing of T cells and dendritic cells to areas of the lymph nodes where T cell priming and the initiation of the adaptive immune response occur. Moreover, CCR7 signaling also contributes to T cell development in the thymus and to lymphorganogenesis. Although the CCR7-CCL19/CCL21 axis evolved to benefit the host, inappropriate regulation or use of these proteins can contribute or cause pathobiology of chronic inflammation, tumorigenesis, and metastasis, as well as autoimmune diseases. Therefore, it appears as the CCR7-CCL19/CCL21 axis is tightly regulated at numerous intersections. Here, we discuss the multiple regulatory mechanism of CCR7 signaling and its influence on CCR7 function. In particular, we focus on the functional diversity of the 2 CCR7 ligands, CCL19 and CCL21, as well as on their impact on biased signaling. The understanding of the molecular determinants of biased signaling and the multiple layers of CCR7 regulation holds the promise for potential future therapeutic intervention.

  4. Loss of Gata4 in Sertoli cells impairs the spermatogonial stem cell niche and causes germ cell exhaustion by attenuating chemokine signaling

    PubMed Central

    Chen, Su-Ren; Tang, Ji-Xin; Cheng, Jin-Mei; Li, Jian; Jin, Cheng; Li, Xiao-Yu; Deng, Shou-Long; Zhang, Yan; Wang, Xiu-Xia; Liu, Yi-Xun

    2015-01-01

    Sertoli cells, the primary somatic cell in the seminiferous epithelium, provide the spermatogonial stem cell (SSC) microenvironment (niche) through physical support and the expression of paracrine factors. However, the regulatory mechanisms within the SSC niche, which is primarily controlled by Sertoli cells, remain largely unknown. GATA4 is a Sertoli cell marker, involved in genital ridge initiation, sex determination and differentiation during the embryonic stage. Here, we showed that neonatal mice with a targeted disruption of Gata4 in Sertoli cells (Gata4flox/flox; Amh-Cre; hereafter termed Gata4 cKO) displayed a loss of the establishment and maintenance of the SSC pool and apoptosis of both gonocyte-derived differentiating spermatogonia and meiotic spermatocytes. Thus, progressive germ cell depletion and a Sertoli-cell-only syndrome were observed as early as the first wave of murine spermatogenesis. Transplantation of germ cells from postnatal day 5 (P5) Gata4 cKO mice into KitW/W-v recipient seminiferous tubules restored spermatogenesis. In addition, microarray analyses of P5 Gata4 cKO mouse testes showed alterations in chemokine signaling factors, including Cxcl12, Ccl3, Cxcr4 (CXCL12 receptor), Ccr1 (CCL3 receptor), Ccl9, Xcl1 and Ccrl2. Deletion of Gata4 in Sertoli cells markedly attenuated Sertoli cell chemotaxis, which guides SSCs or prospermatogonia to the stem cell niche. Finally, we showed that GATA4 transcriptionally regulated Cxcl12 and Ccl9, and the addition of CXCL12 and CCL9 to an in vitro testis tissue culture system increased the number of PLZF+ undifferentiated spermatogonia within Gata4 cKO testes. Together, these results reveal a novel role for GATA4 in controlling the SSC niche via the transcriptional regulation of chemokine signaling shortly after birth. PMID:26473289

  5. Loss of Gata4 in Sertoli cells impairs the spermatogonial stem cell niche and causes germ cell exhaustion by attenuating chemokine signaling.

    PubMed

    Chen, Su-Ren; Tang, Ji-Xin; Cheng, Jin-Mei; Li, Jian; Jin, Cheng; Li, Xiao-Yu; Deng, Shou-Long; Zhang, Yan; Wang, Xiu-Xia; Liu, Yi-Xun

    2015-11-10

    Sertoli cells, the primary somatic cell in the seminiferous epithelium, provide the spermatogonial stem cell (SSC) microenvironment (niche) through physical support and the expression of paracrine factors. However, the regulatory mechanisms within the SSC niche, which is primarily controlled by Sertoli cells, remain largely unknown. GATA4 is a Sertoli cell marker, involved in genital ridge initiation, sex determination and differentiation during the embryonic stage. Here, we showed that neonatal mice with a targeted disruption of Gata4 in Sertoli cells (Gata4(flox/flox); Amh-Cre; hereafter termed Gata4 cKO) displayed a loss of the establishment and maintenance of the SSC pool and apoptosis of both gonocyte-derived differentiating spermatogonia and meiotic spermatocytes. Thus, progressive germ cell depletion and a Sertoli-cell-only syndrome were observed as early as the first wave of murine spermatogenesis. Transplantation of germ cells from postnatal day 5 (P5) Gata4 cKO mice into Kit(W/W-v) recipient seminiferous tubules restored spermatogenesis. In addition, microarray analyses of P5 Gata4 cKO mouse testes showed alterations in chemokine signaling factors, including Cxcl12, Ccl3, Cxcr4 (CXCL12 receptor), Ccr1 (CCL3 receptor), Ccl9, Xcl1 and Ccrl2. Deletion of Gata4 in Sertoli cells markedly attenuated Sertoli cell chemotaxis, which guides SSCs or prospermatogonia to the stem cell niche. Finally, we showed that GATA4 transcriptionally regulated Cxcl12 and Ccl9, and the addition of CXCL12 and CCL9 to an in vitro testis tissue culture system increased the number of PLZF+ undifferentiated spermatogonia within Gata4 cKO testes. Together, these results reveal a novel role for GATA4 in controlling the SSC niche via the transcriptional regulation of chemokine signaling shortly after birth.

  6. LncRNA Directs Cooperative Epigenetic Regulation Downstream of Chemokine Signals

    PubMed Central

    Wang, Shouyu; Liu, Yang; Park, Peter; Qin, Li; Wei, Yongkun; Hawke, David; Hung, Mien-Chie; Lin, Chunru; Yang, Liuqing

    2014-01-01

    Summary LncRNAs are known to regulate a number of different development and tumorigenic processes. Here we report a role for lncRNA BCAR4 in breast cancer metastasis that is mediated by chemokine-induced binding of BCAR4 to two transcription factors with extended regulatory consequences. BCAR4 binding of SNIP1 and PNUTS in response to CCL21 releases the SNIP1's inhibition of p300-dependent histone acetylation that in turn enables the BCAR4-recruited PNUTS to bind H3K18ac and relieve inhibition of RNA Pol II via activation of the PP1 phosphatase. This mechanism activates a noncanonical Hedgehog/GLI2 transcriptional program that promotes cell migration. BCAR4 expression correlates with advanced breast cancers and therapeutic delivery of Locked Nucleic Acids (LNAs) targeting BCAR4 strongly suppresses breast cancer metastasis in mouse models. The findings reveal a disease-relevant lncRNA mechanism consisting of both direct coordinated protein recruitment and indirect regulation of transcription factors. PMID:25416949

  7. A Novel MEK-ERK-AMPK Signaling Axis Controls Chemokine Receptor CCR7-dependent Survival in Human Mature Dendritic Cells*

    PubMed Central

    López-Cotarelo, Pilar; Escribano-Díaz, Cristina; González-Bethencourt, Ivan Luis; Gómez-Moreira, Carolina; Deguiz, María Laura; Torres-Bacete, Jesús; Gómez-Cabañas, Laura; Fernández-Barrera, Jaime; Delgado-Martín, Cristina; Mellado, Mario; Regueiro, José Ramón; Miranda-Carús, María Eugenia; Rodríguez-Fernández, José Luis

    2015-01-01

    Chemokine receptor CCR7 directs mature dendritic cells (mDCs) to secondary lymph nodes where these cells regulate the activation of T cells. CCR7 also promotes survival in mDCs, which is believed to take place largely through Akt-dependent signaling mechanisms. We have analyzed the involvement of the AMP-dependent kinase (AMPK) in the control of CCR7-dependent survival. A pro-apoptotic role for AMPK is suggested by the finding that pharmacological activators induce apoptosis, whereas knocking down of AMPK with siRNA extends mDC survival. Pharmacological activation of AMPK also induces apoptosis of mDCs in the lymph nodes. Stimulation of CCR7 leads to inhibition of AMPK, through phosphorylation of Ser-485, which was mediated by Gi/Gβγ, but not by Akt or S6K, two kinases that control the phosphorylation of AMPK on Ser-485 in other settings. Using selective pharmacological inhibitors, we show that CCR7-induced phosphorylation of AMPK on Ser-485 is mediated by MEK and ERK. Coimmunoprecipitation analysis and proximity ligation assays indicate that AMPK associates with ERK, but not with MEK. These results suggest that in addition to Akt-dependent signaling mechanisms, CCR7 can also promote survival of mDCs through a novel MEK1/2-ERK1/2-AMPK signaling axis. The data also suggest that AMPK may be a potential target to modulate mDC lifespan and the immune response. PMID:25425646

  8. A novel MEK-ERK-AMPK signaling axis controls chemokine receptor CCR7-dependent survival in human mature dendritic cells.

    PubMed

    López-Cotarelo, Pilar; Escribano-Díaz, Cristina; González-Bethencourt, Ivan Luis; Gómez-Moreira, Carolina; Deguiz, María Laura; Torres-Bacete, Jesús; Gómez-Cabañas, Laura; Fernández-Barrera, Jaime; Delgado-Martín, Cristina; Mellado, Mario; Regueiro, José Ramón; Miranda-Carús, María Eugenia; Rodríguez-Fernández, José Luis

    2015-01-09

    Chemokine receptor CCR7 directs mature dendritic cells (mDCs) to secondary lymph nodes where these cells regulate the activation of T cells. CCR7 also promotes survival in mDCs, which is believed to take place largely through Akt-dependent signaling mechanisms. We have analyzed the involvement of the AMP-dependent kinase (AMPK) in the control of CCR7-dependent survival. A pro-apoptotic role for AMPK is suggested by the finding that pharmacological activators induce apoptosis, whereas knocking down of AMPK with siRNA extends mDC survival. Pharmacological activation of AMPK also induces apoptosis of mDCs in the lymph nodes. Stimulation of CCR7 leads to inhibition of AMPK, through phosphorylation of Ser-485, which was mediated by G(i)/Gβγ, but not by Akt or S6K, two kinases that control the phosphorylation of AMPK on Ser-485 in other settings. Using selective pharmacological inhibitors, we show that CCR7-induced phosphorylation of AMPK on Ser-485 is mediated by MEK and ERK. Coimmunoprecipitation analysis and proximity ligation assays indicate that AMPK associates with ERK, but not with MEK. These results suggest that in addition to Akt-dependent signaling mechanisms, CCR7 can also promote survival of mDCs through a novel MEK1/2-ERK1/2-AMPK signaling axis. The data also suggest that AMPK may be a potential target to modulate mDC lifespan and the immune response.

  9. Induction of CXC chemokines in human mesenchymal stem cells by stimulation with secreted frizzled-related proteins through non-canonical Wnt signaling

    PubMed Central

    Bischoff, David S; Zhu, Jian-Hua; Makhijani, Nalini S; Yamaguchi, Dean T

    2015-01-01

    AIM: To investigate the effect of secreted frizzled-related proteins (sFRPs) on CXC chemokine expression in human mesenchymal stem cells (hMSCs). METHODS: CXC chemokines such as CXCL5 and CXCL8 are induced in hMSCs during differentiation with osteogenic differentiation medium (OGM) and may be involved in angiogenic stimulation during bone repair. hMSCs were treated with conditioned medium (CM) from L-cells expressing non-canonical Wnt5a protein, or with control CM from wild type L-cells, or directly with sFRPs for up to 10 d in culture. mRNA expression levels of both CXCL5 and CXCL8 were quantitated by real-time reverse transcriptase-polymerase chain reaction and secreted protein levels of these proteins determined by ELISA. Dose- (0-500 ng/mL) and time-response curves were generated for treatment with sFRP1. Signal transduction pathways were explored by western blot analysis with pan- or phosphorylation-specific antibodies, through use of specific pathway inhibitors, and through use of siRNAs targeting specific frizzled receptors (Fzd)-2 and 5 or the receptor tyrosine kinase-like orphan receptor-2 (RoR2) prior to treatment with sFRPs. RESULTS: CM from L-cells expressing Wnt5a, a non-canonical Wnt, stimulated an increase in CXCL5 mRNA expression and protein secretion in comparison to control L-cell CM. sFRP1, which should inhibit both canonical and non-canonical Wnt signaling, surprisingly enhanced the expression of CXCL5 at 7 and 10 d. Dickkopf1, an inhibitor of canonical Wnt signaling prevented the sFRP-stimulated induction of CXCL5 and actually inhibited basal levels of CXCL5 expression at 7 but not at 10 d post treatment. In addition, all four sFRPs isoforms induced CXCL8 expression in a dose- and time-dependent manner with maximum expression at 7 d with treatment at 150 ng/mL. The largest increases in CXCL5 expression were seen from stimulation with sFRP1 or sFRP2. Analysis of mitogen-activated protein kinase signaling pathways in the presence of OGM showed s

  10. Antibiotic-Induced Cell Wall Fragments of Staphylococcus aureus Increase Endothelial Chemokine Secretion and Adhesiveness for Granulocytes

    PubMed Central

    van Langevelde, P.; Ravensbergen, E.; Grashoff, P.; Beekhuizen, H.; Groeneveld, P. H. P.; van Dissel, J. T.

    1999-01-01

    Antibiotics release inflammatory fragments, such as lipoteichoic acid (LTA) and peptidoglycan (PG), from the cell wall of Staphylococcus aureus. In this study, we exposed S. aureus cultures to a number of β-lactam antibiotics (imipenem, flucloxacillin, and cefamandole) and protein synthesis-inhibiting antibiotics (erythromycin, clindamycin, and gentamicin) and investigated whether supernatants of these cultures differ in their capacity to stimulate endothelial cells (EC). After 24 h of incubation, endothelial adhesiveness for leukocytes, surface expression of various adhesion molecules, and secretion of the chemokines interleukin-8 (IL-8) and monocyte chemotactic protein-1 (MCP-1) were measured. Supernatants of β-lactam-exposed cultures (designated β-lactam supernatants) enhanced the adhesiveness of EC for granulocytes, whereas those of protein synthesis-inhibiting antibiotic-exposed cultures (designated protein synthesis-inhibitor supernatants) did not. This hyperadhesiveness coincided with a higher intercellular adhesion molecule-1 expression on the surface of the stimulated EC. In addition, EC stimulated with β-lactam supernatants secreted significantly higher concentrations of the chemokines IL-8 and MCP-1 than those stimulated with protein synthesis-inhibitor supernatants. The finding that the concentrations of LTA and PG in β-lactam supernatants were much higher than those in protein synthesis-inhibitor supernatants suggests that the observed differences in stimulatory effect between these supernatants are a result of differences in the release of cell wall fragments, although the presence of other stimulatory factors in the supernatants cannot be excluded. In conclusion, our results argue for a release of LTA and PG from S. aureus after exposure to β-lactam antibiotics that enhances the development of a systemic inflammatory response by stimulating EC such that adhesiveness for granulocytes is increased and large amounts of IL-8 and MCP-1 are secreted

  11. Ligand-biased and probe-dependent modulation of chemokine receptor CXCR3 signaling by negative allosteric modulators.

    PubMed

    Bernat, Viachaslau; Brox, Regine; Heinrich, Markus R; Auberson, Yves P; Tschammer, Nuska

    2015-03-01

    Over the last decade, functional selectivity (or ligand bias) has evolved from being a peculiar phenomenon to being recognized as an essential feature of synthetic ligands that target G protein-coupled receptors (GPCRs). The CXC chemokine receptor 3 (CXCR3) is an outstanding platform to study various aspects of biased signaling, because nature itself uses functional selectivity to manipulate receptor signaling. At the same time, CXCR3 is an attractive therapeutic target in the treatment of autoimmune diseases and cancer. Herein we report the discovery of an 8-azaquinazolinone derivative (N-{1-[3-(4-ethoxyphenyl)-4-oxo-3,4-dihydropyrido[2,3-d]pyrimidin-2-yl]ethyl}-4-(4-fluorobutoxy)-N-[(1-methylpiperidin-4-yl)methyl]butanamide, 1 b) that can inhibit CXC chemokine 11 (CXCL11)-dependent G protein activation over β-arrestin recruitment with 187-fold selectivity. This compound also demonstrates probe-dependent activity, that is, it inhibits CXCL11- over CXCL10-mediated G protein activation with 12-fold selectivity. Together with a previously reported biased negative allosteric modulator from our group, the present study provides additional information on the molecular requirements for allosteric modulation of CXCR3.

  12. PDGF-driven proliferation, migration, and IL8 chemokine secretion in human corneal fibroblasts involve JAK2-STAT3 signaling pathway

    PubMed Central

    Sharma, Ajay; Thakkar, Mahesh; Sinha, Sunilima; Mohan, Rajiv R.

    2008-01-01

    Purpose Platelet-derived growth factor (PDGF) is associated with corneal fibroblast migration and proliferation and plays an important role in corneal wound healing. However, the intracellular mechanisms of PDGF-mediated functions in corneal fibroblasts are poorly understood. We tested the hypothesis that PDGF functional activities in the cornea involve the Janus kinase-2/signal transducers and activators of transcription-3 (JAK2-STAT3) signaling pathway and whether PDGF induces the expression of suppressors of cytokine signaling 3 (SOCS3), belonging to the novel family of feedback regulators of cytokine and growth factor activities. Methods Human corneal fibroblast (HSF) cultures were used as an in vitro model for functional analysis. Real-time polymerase chain reactions were performed to quantify gene expression. Immunoprecipitation and immunoblotting techniques were used to measure protein expression. Cell growth, migration, and ELISA assays were used for functional validation. Results Low endogenous levels of STAT3 and SOCS3 mRNA and protein expression were noted in HSFs. PDGF treatment of HSF significantly induced SOCS3 mRNA (3.0–4.5 fold) and protein (1.5–2.5 fold) expression in a time-dependent manner. Similarly, PDGF treatment of HSF significantly increased STAT3 protein expression at two tested time points (2.5–2.96 fold). Cultures exposed to vehicle (control) did not show any change in SOCS3 and STAT3 mRNA or protein expression. An addition of AG-490, a selective inhibitor of the JAK2-STAT3 pathway, significantly inhibited PDGF-mediated STAT3 induction and cell growth and migration in HSF. We also observed that PDGF induced interleukin-8 (IL8) chemokine secretion (2 fold) and AG-490 inhibited IL8 secretion. Conclusions Our data showed that PDGF induced STAT3, SOCS3, and IL8 chemokine secretion in human corneal fibroblasts. Further, PDGF-induced cell growth, migration, and IL8 secretion in corneal fibroblast involve the JAK2-STAT3 signaling pathway

  13. Increased expression of chemokine receptors CCR1 and CCR3 in nasal polyps: molecular basis for recruitment of the granulocyte infiltrate.

    PubMed

    Fundová, P; Funda, D P; Kovář, D; Holý, R; Navara, M; Tlaskalová-Hogenová, H

    2013-05-01

    Inflammatory processes play an important role in the development of nasal polyps (NP), but the etiology and, to a high degree also, the pathogenesis of NP are not fully understood. The role of several cytokines and chemokines such as eotaxins, IL-4, IL-5, IL-6, IL-8, and RANTES has been reported in NP. Herewith, we investigated the expression and pattern of distribution of chemokine receptors CCR1 and CCR3 in nasal polyps. Immunohistochemical detection was carried out in frozen sections of biopsies from 22 NP and 18 nasal mucosa specimens in both the epithelial and stromal compartments. Fluorescence microscopy and computerized image analysis revealed a statistically significant increased number of CCR1 (45.2 ± 2.8 vs. 15.1 ± 1.9, p < 0.001)-positive as well as CCR3 (16.4 ± 1.4 vs. 9.7 ± 1.1, p < 0.001)-positive cells in the stroma of NP compared to nasal mucosa. In comparison to healthy nasal mucosa, increased positivity of CCR3 was detected in the epithelial compartment of NP. Our data suggest that increased expression of CCR1 and CCR3 chemokine receptors may, in accord with various chemokines, contribute to the pathogenesis of nasal polyposis by facilitating increased migration and prolonged accumulation of inflammatory cells, e.g., eosinophils, in the inflammatory infiltrate of NP.

  14. Lymphotropic Virions Affect Chemokine Receptor-Mediated Neural Signaling and Apoptosis: Implications for Human Immunodeficiency Virus Type 1-Associated Dementia

    PubMed Central

    Zheng, Jialin; Ghorpade, Anuja; Niemann, Douglas; Cotter, Robin L.; Thylin, Michael R.; Epstein, Leon; Swartz, Jennifer M.; Shepard, Robin B.; Liu, Xiaojuan; Nukuna, Adeline; Gendelman, Howard E.

    1999-01-01

    Chemokine receptors pivotal for human immunodeficiency virus type 1 (HIV-1) infection in lymphocytes and macrophages (CCR3, CCR5, and CXCR4) are expressed on neural cells (microglia, astrocytes, and/or neurons). It is these cells which are damaged during progressive HIV-1 infection of the central nervous system. We theorize that viral coreceptors could effect neural cell damage during HIV-1-associated dementia (HAD) without simultaneously affecting viral replication. To these ends, we studied the ability of diverse viral strains to affect intracellular signaling and apoptosis of neurons, astrocytes, and monocyte-derived macrophages. Inhibition of cyclic AMP, activation of inositol 1,4,5-trisphosphate, and apoptosis were induced by diverse HIV-1 strains, principally in neurons. Virions from T-cell-tropic (T-tropic) strains (MN, IIIB, and Lai) produced the most significant alterations in signaling of neurons and astrocytes. The HIV-1 envelope glycoprotein, gp120, induced markedly less neural damage than purified virions. Macrophage-tropic (M-tropic) strains (ADA, JR-FL, Bal, MS-CSF, and DJV) produced the least neural damage, while 89.6, a dual-tropic HIV-1 strain, elicited intermediate neural cell damage. All T-tropic strain-mediated neuronal impairments were blocked by the CXCR4 antibody, 12G5. In contrast, the M-tropic strains were only partially blocked by 12G5. CXCR4-mediated neuronal apoptosis was confirmed in pure populations of rat cerebellar granule neurons and was blocked by HA1004, an inhibitor of calcium/calmodulin-dependent protein kinase II, protein kinase A, and protein kinase C. Taken together, these results suggest that progeny HIV-1 virions can influence neuronal signal transduction and apoptosis. This process occurs, in part, through CXCR4 and is independent of CD4 binding. T-tropic viruses that traffic in and out of the brain during progressive HIV-1 disease may play an important role in HAD neuropathogenesis. PMID:10482576

  15. Chemokines: novel targets for breast cancer metastasis

    PubMed Central

    Ali, Simi; Lazennec, Gwendal

    2007-01-01

    Recent studies have highlighted the possible involvement of chemokines and their receptors in breast cancer progression and metastasis. Chemokines and their receptors constitute a superfamily of signalling factors whose prognosis value in breast cancer progression remains unclear. We will examine here the expression pattern of chemokines and their receptors in mammary gland physiology and carcinogenesis. The nature of the cells producing chemokines or harboring chemokine receptors appears to be crucial in certain conditions for example, the infiltration of the primary tumor by leukocytes and angiogenesis. In addition, chemokines, their receptors and the interaction with glycosaminoglycan (GAGs) are key players in the homing of cancer cells to distant metastasis sites. Several lines of evidence, including in vitro and in vivo models, suggest that the mechanism of action of chemokines in cancer development involves the modulation of proliferation, apoptosis, invasion, leukocyte recruitment or angiogenesis. Furthermore, we will discuss the regulation of chemokine network in tumor neovascularity by decoy receptors. The reasons accounting for the deregulation of chemokines and chemokine receptors expression in breast cancer are certainly crucial for the comprehension of chemokine role in breast cancer and are in several cases linked to estrogen receptor status. The targeting of chemokines and chemokine receptors by antibodies, small molecule antagonists, viral chemokine binding proteins and heparins appears as promising tracks to develop therapeutic strategies. Thus there is significant interest in developing strategies to antagonize the chemokine function, and an opportunity to interfere with metastasis, the leading cause of death in most patients. PMID:17717637

  16. Chemokine and Fgf signalling act as opposing guidance cues in formation of the lateral line primordium.

    PubMed

    Breau, Marie A; Wilson, Duncan; Wilkinson, David G; Xu, Qiling

    2012-06-01

    The directional migration of many cell populations occurs as a coherent group. An amenable model is provided by the posterior lateral line in zebrafish, which is formed by a cohesive primordium that migrates from head to tail and deposits future neuromasts at intervals. We found that prior to the onset of migration, the compact state of the primordium is not fully established, as isolated cells with lateral line identity are present caudal to the main primordium. These isolated cells are retained in position such that they fuse with the migrating primordium as it advances, and later contribute to the leading zone and terminal neuromasts. We found that the isolated lateral line cells are positioned by two antagonistic cues: Fgf signalling attracts them towards the primordium, which counteracts Sdf1α/Cxcr4b-mediated caudal attraction. These findings reveal a novel chemotactic role for Fgf signalling in which it enables the coalescence of the lateral line primordium from an initial fuzzy pattern into a compact group of migrating cells.

  17. Lipopolysaccharide of Aggregatibacter actinomycetemcomitans induces the expression of chemokines MCP-1, MIP-1α, and IP-10 via similar but distinct signaling pathways in murine macrophages.

    PubMed

    Park, Ok-Jin; Cho, Min-Kyung; Yun, Cheol-Heui; Han, Seung Hyun

    2015-09-01

    Aggregatibacter actinomycetemcomitans is a Gram-negative bacterium frequently isolated from lesions of patients with localized aggressive periodontitis. Lipopolysaccharide (LPS), a major cell wall component of Gram-negative bacteria, stimulates innate immune cells via Toll-like receptor 4 (TLR4) to initiate inflammatory responses. In this study, we purified LPS from A. actinomycetemcomitans (AaLPS) and investigated its ability to induce the expression of chemokines, which play an important role in recruitment of leukocytes to the infection site. AaLPS induced the expression of chemokines, MCP-1, MIP-1α, and IP-10 in murine macrophages, leading to the infiltration of peripheral blood mononuclear cells in a transwell system. Although TLR4 was essential for the induction of all these chemokines by AaLPS, MCP-1 and MIP-1α expressions were MyD88-dependent, but IP-10 expression was MyD88-independent, as determined using macrophages from mice deficient in TLR4 or MyD88. Furthermore, the activation of ERK and JNK were necessary for the expression of MCP-1 and MIP-1α, whereas p38 MAP kinase and JNK activations were required for IP-10 expression. In addition, IFN-β/STAT1 signaling was exclusively involved in IP-10 expression but not in MCP-1 or MIP-1α expression. AaLPS also activated the transcription factors, NF-κB, AP-1, NF-IL6, and ISRE, all of which are involved in chemokine gene expression. These results suggest that AaLPS induces the expression of chemokines MCP-1, MIP-1α, and IP-10 through TLR4 in murine macrophages. Further, the induction of MCP-1 and MIP-1α requires MyD88, ERK, and JNK, whereas the induction of IP-10 requires JNK, p38 MAP kinase, and IFN-β/STAT1.

  18. Social defeat promotes a reactive endothelium in a brain region-dependent manner with increased expression of key adhesion molecules, selectins and chemokines associated with the recruitment of myeloid cells to the brain.

    PubMed

    Sawicki, C M; McKim, D B; Wohleb, E S; Jarrett, B L; Reader, B F; Norden, D M; Godbout, J P; Sheridan, J F

    2015-08-27

    Repeated social defeat (RSD) in mice causes myeloid cell trafficking to the brain that contributes to the development of prolonged anxiety-like behavior. Myeloid cell recruitment following RSD occurs in regions where neuronal and microglia activation is observed. Thus, we hypothesized that crosstalk between neurons, microglia, and endothelial cells contributes to brain myeloid cell trafficking via chemokine signaling and vascular adhesion molecules. Here we show that social defeat caused an exposure- and brain region-dependent increase in several key adhesion molecules and chemokines involved in the recruitment of myeloid cells. For example, RSD induced distinct patterns of adhesion molecule expression that may explain brain region-dependent myeloid cell trafficking. VCAM-1 and ICAM-1 mRNA expression were increased in an exposure-dependent manner. Furthermore, RSD-induced VCAM-1 and ICAM-1 protein expression were localized to the vasculature of brain regions implicated in fear and anxiety responses, which spatially corresponded to previously reported patterns of myeloid cell trafficking. Next, mRNA expression of additional adhesion molecules (E- and P-selectin, PECAM-1) and chemokines (CXCL1, CXCL2, CXCL12, CCL2) were determined in the brain. Social defeat induced an exposure-dependent increase in mRNA levels of E-selectin, CXCL1, and CXCL2 that increased with additional days of social defeat. While CXCL12 was unaffected by RSD, CCL2 expression was increased by six days of social defeat. Last, comparison between enriched CD11b(+) cells (microglia/macrophages) and enriched GLAST-1(+)/CD11b(-) cells (astrocytes) revealed RSD increased mRNA expression of IL-1β, CCL2, and CXCL2 in microglia/macrophages but not in astrocytes. Collectively, these data indicate that key mediators of leukocyte recruitment were increased in the brain vasculature following RSD in an exposure- and brain region-dependent manner.

  19. Local release from affinity-based polymers increases urethral concentration of the stem cell chemokine CCL7 in rats.

    PubMed

    Rivera-Delgado, Edgardo; Sadeghi, Zhina; Wang, Nick X; Kenyon, Jonathan; Satyanarayan, Sapna; Kavran, Michael; Flask, Chris; Hijaz, Adonis Z; von Recum, Horst A

    2016-04-21

    The protein chemokine (C-C motif) ligand 7 (CCL7) is significantly over-expressed in urethral and vaginal tissues immediately following vaginal distention in a rat model of stress urinary incontinence. Further evidence, in this scenario and other clinical scenarios, indicates CCL7 stimulates stem cell homing for regenerative repair. This CCL7 gradient is likely absent or compromised in the natural repair process of women who continue to suffer from SUI into advanced age. We evaluated the feasibility of locally providing this missing CCL7 gradient by means of an affinity-based implantable polymer. To engineer these polymers we screened the affinity of different proteoglycans, to use them as CCL7-binding hosts. We found heparin to be the strongest binding host for CCL7 with a 0.323 nM dissociation constant. Our experimental approach indicates conjugation of heparin to a polymer backbone (using either bovine serum albumin or poly (ethylene glycol) as the base polymer) can be used as a delivery system capable of providing sustained concentrations of CCL7 in a therapeutically useful range up to a month in vitro. With this approach we are able to detect, after polymer implantation, significant increase in CCL7 in the urethral tissue directly surrounding the polymer implants with only trace amounts of human CCL7 present in the blood of the animals. Whole animal serial sectioning shows evidence of retention of locally injected human mesenchymal stem cells (hMSCs) only in animals with sustained CCL7 delivery, 2 weeks after affinity-polymers were implanted.

  20. Dogs infected with the blood trypomastigote form of Trypanosoma cruzi display an increase expression of cytokines and chemokines plus an intense cardiac parasitism during acute infection.

    PubMed

    de Souza, Sheler Martins; Vieira, Paula Melo de Abreu; Roatt, Bruno Mendes; Reis, Levi Eduardo Soares; da Silva Fonseca, Kátia; Nogueira, Nívia Carolina; Reis, Alexandre Barbosa; Tafuri, Washington Luiz; Carneiro, Cláudia Martins

    2014-03-01

    The recent increase in immigration of people from areas endemic for Chagas disease (Trypanosoma cruzi) to the United States and Europe has raised concerns about the transmission via blood transfusion and organ transplants in these countries. Infection by these pathways occurs through blood trypomastigotes (BT), and these forms of T. cruzi are completely distinct of metacyclic trypomastigotes (MT), released by triatomine vector, in relation to parasite-host interaction. Thus, research comparing infection with these different infective forms is important for explaining the potential impacts on the disease course. Here, we investigated tissue parasitism and relative mRNA expression of cytokines, chemokines, and chemokine receptors in the heart during acute infection by MT or BT forms in dogs. BT-infected dogs presented a higher cardiac parasitism, increased relative mRNA expression of pro-inflammatory and immunomodulatory cytokines and of the chemokines CCL3/MIP-1α, CCL5/RANTES, and the chemokine receptor CCR5 during the acute phase of infection, as compared to MT-infected dogs. These results suggest that infection with BT forms may lead to an increased immune response, as revealed by the cytokines ratio, but this kind of immune response was not able to control the cardiac parasitism. Infection with the MT form presented an increase in the relative mRNA expression of IL-12p40 as compared to that of IL-10 or TGF-β1. Correlation analysis showed increased relative mRNA expression of IFN-γ as well as IL-10, which may be an immunomodulatory response, as well as an increase in the correlation of CCL5/RANTES and its CCR5 receptor. Our findings revealed a difference between inoculum sources of T. cruzi, as vectorial or transfusional routes of T. cruzi infection may trigger distinct parasite-host interactions during the acute phase, which may influence immunopathological aspects of Chagas disease.

  1. [Interceptors:--"silent" chemokine receptors].

    PubMed

    Grodecka, Magdalena; Waśniowska, Kazimiera

    2007-01-01

    The physiological effect caused by chemokines is regulated by interactions with a group of rodopsin-like G protein-coupled receptors (GPCRs). These receptors share a number of common features: the polypeptide chain is a 7-transmembrane ?-helix (7 TMD motif) and the region involved in G-protein interaction (the DRYLAIV sequence) is located in the second transmembrane loop. So far, 19 chemokine receptors have been identified. Three of them (Duffy glycoprotein, D6, and CCX-CKR proteins), although structurally related to other GPCRs, lack the ability of G-protein signal transduction. Instead, they efficiently internalize their cognate ligands, regulating chemokine levels in various body compartments. These three proteins are suggested to form a distinct chemokine receptor family, designated "interceptors" or "silent" chemokine receptors.

  2. Structural perspectives on antimicrobial chemokines

    PubMed Central

    Nguyen, Leonard T.; Vogel, Hans J.

    2012-01-01

    Chemokines are best known as signaling proteins in the immune system. Recently however, a large number of human chemokines have been shown to exert direct antimicrobial activity. This moonlighting activity appears to be related to the net high positive charge of these immune signaling proteins. Chemokines can be divided into distinct structural elements and some of these have been studied as isolated peptide fragments that can have their own antimicrobial activity. Such peptides often encompass the α-helical region found at the C-terminal end of the parent chemokines, which, similar to other antimicrobial peptides, adopt a well-defined membrane-bound amphipathic structure. Because of their relatively small size, intact chemokines can be studied effectively by NMR spectroscopy to examine their structures in solution. In addition, NMR relaxation experiments of intact chemokines can provide detailed information about the intrinsic dynamic behavior; such analyses have helped for example to understand the activity of TC-1, an antimicrobial variant of CXCL7/NAP-2. With chemokine dimerization and oligomerization influencing their functional properties, the use of NMR diffusion experiments can provide information about monomer-dimer equilibria in solution. Furthermore, NMR chemical shift perturbation experiments can be used to map out the interface between self-associating subunits. Moreover, the unusual case of XCL1/lymphotactin presents a chemokine that can interconvert between two distinct folds in solution, both of which have been elucidated. Finally, recent advances have allowed for the determination of the structures of chemokines in complex with glycosaminoglycans, a process that could interfere with their antimicrobial activity. Taken together, these studies highlight several different structural facets that contribute to the way in which chemokines exert their direct microbicidal actions. PMID:23293636

  3. Novel human cytomegalovirus viral chemokines, vCXCL-1s, display functional selectivity for neutrophil signaling and function

    PubMed Central

    Heo, Jinho; Dogra, Pranay; Masi, Tom J.; Pitt, Elisabeth A.; de Kruijf, Petra; Smit, Martine J.; Sparer, Tim E.

    2015-01-01

    Human cytomegalovirus (HCMV) uses members of the hematopoietic system including neutrophils for dissemination throughout the body. HCMV encodes a viral chemokine, vCXCL-1, that is postulated to attract neutrophils for dissemination within the host. The gene encoding vCXCL-1, UL146, is one of the most variable genes in the HCMV genome. Why HCMV has evolved this hypervariability and how this affects the virus’ dissemination/pathogenesis is unknown. Because the vCXCL-1 hypervariability maps to important binding and activation domains, we hypothesized that vCXCL-1s differentially activate neutrophils, which could contribute to HCMV dissemination and/or pathogenesis. In order to test whether these viral chemokines affect neutrophil function, we generated vCXCL-1 proteins from 11 different clades from clinical isolates from HCMV-congenitally infected infants. All vCXCL-1s were able to induce calcium flux at a concentration of 100 nM and integrin expression on human peripheral blood neutrophils (PBNs) in spite of differences in affinity for the CXCR1 and CXCR2 receptors. In fact their affinity for CXCR1 or CXCR2 did not directly correlate with chemotaxis, G protein-dependent and independent (β-arrestin2) activation, or secondary chemokine (CCL22) expression. Our data suggest that vCXCL-1 polymorphisms impact the binding affinity, receptor usage, and differential PBN activation that could contribute to HCMV dissemination and/or pathogenesis. PMID:25987741

  4. C-C chemokine receptor type 2 (CCR2) signaling protects neonatal male mice with hypoxic-ischemic hippocampal damage from developing spatial learning deficits.

    PubMed

    Pimentel-Coelho, Pedro M; Michaud, Jean-Philippe; Rivest, Serge

    2015-06-01

    Chemokines are a family of cytokines involved in the chemotaxis of leukocytes and other target cells by binding to specific G-protein-coupled receptors on their membranes. As such, the activation of C-C chemokine receptor type 2 (CCR2) is involved in the mobilization of "inflammatory" monocytes from bone marrow and in their recruitment to the brain under inflammatory/pathological conditions. In this study, we investigated whether CCR2 signaling could affect the progression of learning deficits and hippocampal damage in a model of neonatal hypoxic-ischemic (HI) brain injury. Postnatal day 3 wild-type (WT) and CCR2 knockout (KO) mice of both sexes were subjected to the Rice-Vannucci model of neonatal hypoxia-ischemia and were followed for up to 14 weeks. HI CCR2 KO male mice were the only animals to exhibit long-term spatial learning deficits in the T-water maze task, compared to their corresponding sham-operated controls. CCR2 KO mouse pups of both sexes had a lower number of circulating monocytes, although only HI CCR2 KO male mice exhibited reduced numbers of activated macrophages/microglia in the damaged hippocampus, compared to WT mice. However, no differences were observed in hippocampal atrophy between HI CCR2 KO and HI WT mice. These results suggest that CCR2 signaling can protect neonatal mice from developing spatial learning deficits after a HI insult, in a sex-specific fashion.

  5. Targeting the chemokines in cardiac repair.

    PubMed

    Cavalera, Michele; Frangogiannis, Nikolaos G

    2014-01-01

    Chemokines are a family of chemotactic cytokines that play an essential role in leukocyte trafficking. Upregulation of both CC and CXC chemokines is a hallmark of the inflammatory and reparative response following myocardial infarction. Release of danger signals from dying cells and damaged extracellular matrix activates innate immune pathways that stimulate chemokine synthesis. Cytokineand chemokine-driven adhesive interactions between endothelial cells and leukocytes mediate extravasation of immune cells into the infarct. CXC chemokines (such as interleukin-8) are bound to glycosaminoglycans on the endothelial surface and activate captured neutrophils, inducing expression of integrins. CC chemokines (such as monocyte chemoattractant protein (MCP)-1) mediate recruitment of proinflammatory and phagocytotic mononuclear cells into the infarct. CC Chemokines may also regulate late infiltration of the healing infarct with inhibitory leukocytes that suppress inflammation and restrain the post-infarction immune response. Non-hematopoietic cells are also targeted by chemokines; in healing infarcts, the CXC chemokine Interferon-γ inducible Protein (IP)-10 exerts antifibrotic actions, inhibiting fibroblast migration. Another member of the CXC subfamily, Stromal cell-derived Factor (SDF)-1, may protect the infarcted heart by activating pro-survival signaling in cardiomyocytes, while exerting angiogenic actions through chemotaxis of endothelial progenitors. Several members of the chemokine family may be promising therapeutic targets to attenuate adverse remodeling in patients with myocardial infarction.

  6. Increase in chemokines CXCL10 and CCL2 in blood from pigs infected with high compared to low virulence African swine fever virus isolates.

    PubMed

    Fishbourne, Emma; Hutet, Evelyne; Abrams, Charles; Cariolet, Roland; Le Potier, Marie-Frédérique; Takamatsu, Haru-H; Dixon, Linda K

    2013-10-01

    Modulation of the expression of chemokines and chemokine receptors in whole blood was compared following infection of pigs with high and low virulence isolates of African swine fever virus. Levels of mRNAs for CCL2, CCL3L1, CCL4, CXCL10, CCR1 and CCR5 were significantly increased in at least one time point following infection in two experiments and CCL5, CCR9 and CXCR4 mRNA were significantly increased in one of the experiments. The results showed that greatest fold increases in mRNAs for CXCL10 and CCL2 were observed following infection of pigs. CXCL10 mRNA was increased by up to 15 fold in infected compared to uninfected pigs. CXCL10 protein was also detected in serum from pigs infected with the high virulence Benin 97/1 isolate. Levels of CCL2 mRNA were increased in pigs infected with high virulence Benin 97/1 isolate compared to low virulence OURT88/3 isolate and this correlated with an increase of greater than 30 fold in levels of CCL2 protein detected in serum from pigs infected with this isolate. An increase in overall chemotaxis active compounds in defibrinated plasma samples from Benin 97/1 infected pigs was observed at 3 days post-infection (dpi) and a decrease by 7 dpi as measured by chemotaxis assay using normal pig leucocytes in vitro. Increased levels of CXCL10 may either contribute to the activation of lymphocyte priming toward the Th1 phenotype or induction of T lymphocyte apoptosis. Increased levels of CCL2, a chemoattractant for macrophages, may result in increased recruitment of monocytes from bone marrow thus increasing the pool of cells susceptible to infection.

  7. Histone deacetylase inhibitor-temozolomide co-treatment inhibits melanoma growth through suppression of Chemokine (C-C motif) ligand 2-driven signals

    PubMed Central

    Cesare, Michelandrea De; Arrighetti, Noemi; Manenti, Giacomo; Ciusani, Emilio; Verderio, Paolo; Ciniselli, Chiara M.; Cominetti, Denis; Carenini, Nives; Corna, Elisabetta; Zaffaroni, Nadia; Rodolfo, Monica; Rivoltini, Licia

    2014-01-01

    Target-specific agents used in melanoma are not curative, and chemokines are being implicated in drug-resistance to target-specific agents. Thus, the use of conventional agents in rationale combinations may result in optimization of therapy. Because histone deacetylases participate in tumor development and progression, the combination of the pan-inhibitor SAHA and temozolomide might provide a therapeutic advantage. Here, we show synergism between the two drugs in mutant BRAF cell lines, in association with decreased phosphorylation of cell survival proteins (e.g., C-Jun-N-terminal-kinase, JNK). In the spontaneous ret transgenic mouse melanoma model, combination therapy produced a significant disease onset delay and down-regulation of Chemokine (C-C motif) ligand 2 (CCL2), JNK, and of Myeloid-derived suppressor cell recruitment. Co-incubation with a CCL2-blocking-antibody enhanced in vitro cell sensitivity to temozolomide. Conversely, recombinant CCL2 activated JNK in human tumor melanoma cells. In keeping with these results, the combination of a JNK-inhibitor with temozolomide was synergistic. By showing that down-regulation of CCL2-driven signals by SAHA and temozolomide via JNK contributes to reduce melanoma growth, we provide a rationale for the therapeutic advantage of the drug combination. This combination strategy may be effective because of interference both with tumor cell and tumor microenvironment. PMID:24980831

  8. CC chemokine ligand 19 secreted by mature dendritic cells increases naive T cell scanning behavior and their response to rare cognate antigen.

    PubMed

    Kaiser, Andrew; Donnadieu, Emmanuel; Abastado, Jean-Pierre; Trautmann, Alain; Nardin, Alessandra

    2005-08-15

    For immune responses to take place, naive T cells have to encounter, adhere to, and be stimulated by dendritic cells (DCs). In murine lymph nodes, T cells move randomly and scan the surface of multiple DCs. The factors controlling this motility as well as its consequences remain unclear. We have monitored by video-imaging the earliest steps of the interaction between human DCs and autologous naive CD4+ T cells in the absence of exogenous Ags. Mature, but not immature, DCs were able to elicit small calcium responses in naive T cells along with cell polarization and random motility, resulting in an efficient scanning of DC surfaces by T cells. We identified CCL19 as a key factor enabling all these early T cell responses, including the occurrence of calcium transients. Because this chemokine did not influence the strength of naive T cell adhesion to DCs, enhanced LFA-1 affinity for ICAM-1 was not the main mechanism by which CCL19 increased Ag-independent calcium transients. However, concomitantly to T cell motility, CCL19 augmented the frequency of T cell responses to rare anti-CD3/CD28-coated beads, used as surrogate APCs. We thus propose a new role for CCL19 in humans: by conditioning T cells into a motile DC-scanning state, this chemokine promotes Ag-independent responses and increases the probability of cognate MHC-peptide encounter.

  9. CXCL12/CXCR4 chemokine signaling in spinal glia induces pain hypersensitivity through MAPKs-mediated neuroinflammation in bone cancer rats.

    PubMed

    Hu, Xue-Ming; Liu, Yan-Nan; Zhang, Hai-Long; Cao, Shou-Bin; Zhang, Ting; Chen, Li-Ping; Shen, Wen

    2015-02-01

    The activation of MAPK pathways in spinal cord and subsequent production of proinflammatory cytokines in glial cells contribute to the development of spinal central sensitization, the basic mechanism underlying bone cancer pain (BCP). Our previous study showed that spinal CXCL12 from astrocytes mediates BCP generation by binding to CXCR4 in both astrocyters and microglia. Here, we verified that CXCL12/CXCR4 signaling contributed to BCP through a MAPK-mediated mechanism. In naïve rats, a single intrathecal administration of CXCL12 considerably induced pain hyperalgesia and phosphorylation expression of spinal MAPK members (including extracellular signal-regulated kinase, p38, and c-Jun N-terminal kinase), which could be partially prevented by pre-treatment with CXCR4 inhibitor AMD3100. This CXCL12-induced hyperalgesia was also reduced by MAPK inhibitors. In bone cancer rats, tumor cell inoculation into the tibial cavity caused prominent and persistent pain hyperalgesia, and associated with up-regulation of CXCL12 and CXCR4, activation of glial cells, phosphorylation of MAPKs, and production of proinflammatory cytokines in the spinal cord. These tumor cell inoculation-induced behavioral and neurochemical alterations were all suppressed by blocking CXCL12/CXCR4 signaling or MAPK pathways. Taken together, these results demonstrate that spinal MAPK pathways mediated CXCL12/CXCR4-induced pain hypersensitivity in bone cancer rats, which could be druggable targets for alleviating BCP and glia-derived neuroinflammation. Following tumor cell inoculation, chemokine CXCL12 from astrocytes spreads around the spinal environment, resulting in functional activation of CXCR4-expressing astrocytes and microglia. Once glia are activated, they may initiate MAPK (mitogen-activated protein kinase) pathways, and subsequently produce proinflammatory cytokines and chemokines. Among them, CXCL12 could reinforce the astrocytic and microglial activation in autocrine and paracrine manners

  10. The chemokine network. II. On how polymorphisms and alternative splicing increase the number of molecular species and configure intricate patterns of disease susceptibility

    PubMed Central

    Colobran, R; Pujol-Borrell, R; Armengol, M P; Juan, M

    2007-01-01

    In this second review on chemokines, we focus on the polymorphisms and alternative splicings and on their consequences in disease. Because chemokines are key mediators in the pathogenesis of inflammatory, autoimmune, vascular and neoplastic disorders, a large number of studies attempting to relate particular polymorphisms of chemokines to given diseases have already been conducted, sometimes with contradictory results. Reviewing the published data, it becomes evident that some chemokine genes that are polymorphic have alleles that are found repeatedly, associated with disease of different aetiologies but sharing some aspects of pathogenesis. Among CXC chemokines, single nucleotide polymorphisms (SNPs) in the CXCL8 and CXCL12 genes stand out, as they have alleles associated with many diseases such as asthma and human immunodeficiency virus (HIV), respectively. Of CC chemokines, the stronger associations occur among alleles from SNPs in CCL2 and CCL5 genes and a number of inflammatory conditions. To understand how chemokines contribute to disease it is also necessary to take into account all the isoforms resulting from differential splicing. The first part of this review deals with polymorphisms and the second with the diversity of molecular species derived from each chemokine gene due to alternative splicing phenomena. The number of molecular species and the level of expression of each of them for every chemokine and for each functionally related group of chemokines reaches a complexity that requires new modelling algorithms akin to those proposed in systems biology approaches. PMID:17848170

  11. Differential structural remodelling of heparan sulfate by chemokines: the role of chemokine oligomerization

    PubMed Central

    Migliorini, Elisa; Salanga, Catherina L.; Thakar, Dhruv

    2017-01-01

    Chemokines control the migration of cells in normal physiological processes and in the context of disease such as inflammation, autoimmunity and cancer. Two major interactions are involved: (i) binding of chemokines to chemokine receptors, which activates the cellular machinery required for movement; and (ii) binding of chemokines to glycosaminoglycans (GAGs), which facilitates the organization of chemokines into haptotactic gradients that direct cell movement. Chemokines can bind and activate their receptors as monomers; however, the ability to oligomerize is critical for the function of many chemokines in vivo. Chemokine oligomerization is thought to enhance their affinity for GAGs, and here we show that it significantly affects the ability of chemokines to accumulate on and be retained by heparan sulfate (HS). We also demonstrate that several chemokines differentially rigidify and cross-link HS, thereby affecting HS rigidity and mobility, and that HS cross-linking is significantly enhanced by chemokine oligomerization. These findings suggest that chemokine–GAG interactions may play more diverse biological roles than the traditional paradigms of physical immobilization and establishment of chemokine gradients; we hypothesize that they may promote receptor-independent events such as physical re-organization of the endothelial glycocalyx and extracellular matrix, as well as signalling through proteoglycans to facilitate leukocyte adhesion and transmigration. PMID:28123055

  12. Enhancement of Chemokine Function as an Immunomodulatory Strategy Employed by Human Herpesviruses

    PubMed Central

    Viejo-Borbolla, Abel; Martinez-Martín, Nadia; Nel, Hendrik J.; Rueda, Patricia; Martín, Rocío; Blanco, Soledad; Arenzana-Seisdedos, Fernando; Thelen, Marcus; Fallon, Padraic G.; Alcamí, Antonio

    2012-01-01

    Herpes simplex virus (HSV) types 1 and 2 are highly prevalent human neurotropic pathogens that cause a variety of diseases, including lethal encephalitis. The relationship between HSV and the host immune system is one of the main determinants of the infection outcome. Chemokines play relevant roles in antiviral response and immunopathology, but the modulation of chemokine function by HSV is not well understood. We have addressed the modulation of chemokine function mediated by HSV. By using surface plasmon resonance and crosslinking assays we show that secreted glycoprotein G (SgG) from both HSV-1 and HSV-2 binds chemokines with high affinity. Chemokine binding activity was also observed in the supernatant of HSV-2 infected cells and in the plasma membrane of cells infected with HSV-1 wild type but not with a gG deficient HSV-1 mutant. Cell-binding and competition experiments indicate that the interaction takes place through the glycosaminoglycan-binding domain of the chemokine. The functional relevance of the interaction was determined both in vitro, by performing transwell assays, time-lapse microscopy, and signal transduction experiments; and in vivo, using the air pouch model of inflammation. Interestingly, and in contrast to what has been observed for previously described viral chemokine binding proteins, HSV SgGs do not inhibit chemokine function. On the contrary, HSV SgGs enhance chemotaxis both in vitro and in vivo through increasing directionality, potency and receptor signaling. This is the first report, to our knowledge, of a viral chemokine binding protein from a human pathogen that increases chemokine function and points towards a previously undescribed strategy of immune modulation mediated by viruses. PMID:22319442

  13. A novel CXCR3-B chemokine receptor-induced growth-inhibitory signal in cancer cells is mediated through the regulation of Bach-1 protein and Nrf2 protein nuclear translocation.

    PubMed

    Balan, Murugabaskar; Pal, Soumitro

    2014-02-07

    Chemokines and their receptors play diverse roles in regulating cancer growth and progression. The receptor CXCR3 can have two splice variants with opposite functions. CXCR3-A promotes cell growth, whereas CXCR3-B mediates growth-inhibitory signals. However, the negative signals through CXCR3-B in cancer cells are not well characterized. In this study, we found that CXCR3-B-mediated signaling in MCF-7 and T47D breast cancer cells induced apoptotic cell death. Signals through CXCR3-B decreased the levels of the antiapoptotic proteins Bcl-2 and Bcl-xL and increased the expression of apoptotic cleaved poly(ADP-ribose) polymerase. Along with up-regulation in apoptosis, CXCR3-B signals were associated with a decrease in cellular autophagy with reduced levels of the autophagic markers Beclin-1 and LC3B. Notably, CXCR3-B down-regulated the expression of the cytoprotective and antiapoptotic molecule heme oxygenase-1 (HO-1) at the transcriptional level. There was an increased nuclear localization of Bach-1 and nuclear export of Nrf2, which are important negative and positive transcription factors, respectively, for HO-1 expression. We also observed that CXCR3-B promoted the activation of p38 MAPK and the inhibition of ERK-1/2. CXCR3-B could not induce cancer cell apoptosis at the optimal level when we either inhibited p38 activity or knocked down Bach-1. Further, CXCR3-B-induced apoptosis was down-regulated when we overexpressed HO-1. Together, our data suggest that CXCR3-B mediates a growth-inhibitory signal in breast cancer cells through the modulations of nuclear translocation of Bach-1 and Nrf2 and down-regulation of HO-1. We suggest that the induction of CXCR3-B-mediated signaling can serve as a novel therapeutic approach where the goal is to promote tumor cell apoptosis.

  14. The Role of Chemokines in Mesenchymal Stem Cell Homing to Wounds

    PubMed Central

    Hocking, Anne M.

    2015-01-01

    Significance: Mesenchymal stem cells (MSCs) are being administered to cutaneous wounds with the goal of accelerating wound closure and promoting regeneration instead of scar formation. An ongoing challenge for cell-based therapies is achieving effective and optimal targeted delivery and engraftment at the site of injury. Contributing to this challenge is our incomplete understanding of endogenous MSC homing to sites of injury. Recent Advances: Chemokines and their receptors are now recognized as important mediators of stem cell homing. To date, the most studied chemokine–chemokine receptor axis in MSC homing to wounds is CXCL12-CXCR4 but recent work suggests that CCL27-CCR10 and CCL21-CCR7 may also be involved. Critical Issues: Strategies to enhance chemokine-mediated MSC homing to wounds are using a variety of approaches to amplify the chemokine signal at the wound site and/or overexpress specific chemokine receptors on the surface of the MSC. Future Directions: Harnessing chemokine signaling may enhance the therapeutic effects of stem cell therapy by increasing the number of both exogenous and endogenous stem cells recruited to the site of injury. Alternatively, chemokine-based therapies directly targeting endogenous stem cells may circumvent the need for the time-consuming and costly isolation and expansion of autologous stem cells prior to therapeutic administration. PMID:26543676

  15. Increased expression of chemokine receptor CCR3 and its ligands in ulcerative colitis: the role of colonic epithelial cells in in vitro studies.

    PubMed

    Manousou, P; Kolios, G; Valatas, V; Drygiannakis, I; Bourikas, L; Pyrovolaki, K; Koutroubakis, I; Papadaki, H A; Kouroumalis, E

    2010-11-01

    Human colonic epithelial cells express T helper type 1 (Th1)-associated chemoattractants, yet little is known about the production of Th2-associated chemoattractants. CCL11/eotaxin-1, CCL24/eotaxin-2 and CCL26/eotaxin-3 are known to attract CCR3-expressing, Th2-polarized lymphocytes. We studied constitutive and inflammation-induced expression and production of CCR3 together with its ligands in the colon and peripheral blood of patients with inflammatory bowel disease (IBD) by flow cytometry, reverse transcription–polymerase chain reaction (RT–PCR) and enzyme-linked immunosorbent assay (ELISA). We further defined the regulated expression of these chemokines by RT–PCR and ELISA using cultured human epithelial cell lines. A higher fraction of peripheral T lymphocytes were found to be positive for CCR3 in patients with ulcerative colitis (UC) compared to Crohn’s disease (CD), while almost no CCR3(+) T cells were found in normal controls (NC). Similarly, higher and more frequent expression of CCR3 was observed in colonic biopsies from patients with UC, regardless of the disease activity, when compared to CD or NCs. Serum CCL11/eotaxin-1 was increased significantly in UC (306 ± 87 pg/ml) and less so in CD (257 ± 43 pg/ml), whereas CCL24/eotaxin-2, and CCL26/eotaxin-3 were increased only in UC. Colonic expression of the three chemokines was minimal in NCs but high in inflammatory bowel diseases (especially UC) and was independent of disease activity. Th2, and to a lesser extent Th1, cytokines were able to induce expression and production of all three eotaxins from colonic epithelial cells in culture. CCR3 and ligands over-expression would appear to be a characteristic of UC. The production of CCR3 ligands by human colonic epithelial cells suggests further that epithelium can play a role in modulating pathological T cell-mediated mucosal inflammation.

  16. Synergy between coproduced CC and CXC chemokines in monocyte chemotaxis through receptor-mediated events.

    PubMed

    Gouwy, Mieke; Struyf, Sofie; Noppen, Samuel; Schutyser, Evemie; Springael, Jean-Yves; Parmentier, Marc; Proost, Paul; Van Damme, Jo

    2008-08-01

    CC and CXC chemokines coinduced in fibroblasts and leukocytes by cytokines and microbial agents determine the number of phagocytes infiltrating into inflamed tissues. Interleukin-8/CXCL8 and stromal cell-derived factor-1/CXCL12 significantly and dose-dependently increased the migration of monocytes, expressing the corresponding CXC chemokine receptors CXCR2 and CXCR4, toward suboptimal concentrations of the monocyte chemotactic proteins CCL2 or CCL7. These findings were confirmed using different chemotaxis assays and monocytic THP-1 cells. In contrast, the combination of two CC chemokines (CCL2 plus CCL7) or two CXC chemokines (CXCL8 plus CXCL12) did not provide synergy in monocyte chemotaxis. These data show that chemokines competing for related receptors and using similar signaling pathways do not synergize. Receptor heterodimerization is probably not essential for chemokine synergy as shown in CXCR4/CCR2 cotransfectants. It is noteworthy that CCL2 mediated extracellular signal-regulated kinase 1/2 phosphorylation and calcium mobilization was significantly enhanced by CXCL8 in monocytes, indicating cooperative downstream signaling pathways during enhanced chemotaxis. Moreover, in contrast to intact CXCL12, truncated CXCL12(3-68), which has impaired receptor signaling capacity but can still desensitize CXCR4, was unable to synergize with CCL2 in monocytic cell migration. Furthermore, AMD3100 and RS102895, specific CXCR4 and CCR2 inhibitors, respectively, reduced the synergistic effect between CCL2 and CXCL12 significantly. These data indicate that for synergistic interaction between chemokines binding and signaling of the two chemokines via their proper receptors is necessary.

  17. Curcumin mediates oxaliplatin-acquired resistance reversion in colorectal cancer cell lines through modulation of CXC-Chemokine/NF-κB signalling pathway

    PubMed Central

    Ruiz de Porras, Vicenç; Bystrup, Sara; Martínez-Cardús, Anna; Pluvinet, Raquel; Sumoy, Lauro; Howells, Lynne; James, Mark I.; Iwuji, Chinenye; Manzano, José Luis; Layos, Laura; Bugés, Cristina; Abad, Albert; Martínez-Balibrea, Eva

    2016-01-01

    Resistance to oxaliplatin (OXA) is a complex process affecting the outcomes of metastatic colorectal cancer (CRC) patients treated with this drug. De-regulation of the NF-κB signalling pathway has been proposed as an important mechanism involved in this phenomenon. Here, we show that NF-κB was hyperactivated in in vitro models of OXA-acquired resistance but was attenuated by the addition of Curcumin, a non-toxic NF-κB inhibitor. The concomitant combination of Curcumin + OXA was more effective and synergistic in cell lines with acquired resistance to OXA, leading to the reversion of their resistant phenotype, through the inhibition of the NF-κB signalling cascade. Transcriptomic profiling revealed the up-regulation of three NF-κB-regulated CXC-chemokines, CXCL8, CXCL1 and CXCL2, in the resistant cells that were more efficiently down-regulated after OXA + Curcumin treatment as compared to the sensitive cells. Moreover, CXCL8 and CXCL1 gene silencing made resistant cells more sensitive to OXA through the inhibition of the Akt/NF-κB pathway. High expression of CXCL1 in FFPE samples from explant cultures of CRC patients-derived liver metastases was associated with response to OXA + Curcumin. In conclusion, we suggest that combination of OXA + Curcumin could be an effective treatment, for which CXCL1 could be used as a predictive marker, in CRC patients. PMID:27091625

  18. Prenatal exposure to ethanol stimulates hypothalamic CCR2 chemokine receptor system: Possible relation to increased density of orexigenic peptide neurons and ethanol drinking in adolescent offspring.

    PubMed

    Chang, G-Q; Karatayev, O; Leibowitz, S F

    2015-12-03

    Clinical and animal studies indicate that maternal consumption of ethanol during pregnancy increases alcohol drinking in the offspring. Possible underlying mechanisms may involve orexigenic peptides, which are stimulated by prenatal ethanol exposure and themselves promote drinking. Building on evidence that ethanol stimulates neuroimmune factors such as the chemokine CCL2 that in adult rats is shown to colocalize with the orexigenic peptide, melanin-concentrating hormone (MCH) in the lateral hypothalamus (LH), the present study sought to investigate the possibility that CCL2 or its receptor CCR2 in LH is stimulated by prenatal ethanol exposure, perhaps specifically within MCH neurons. Our paradigm of intraoral administration of ethanol to pregnant rats, at low-to-moderate doses (1 or 3g/kg/day) during peak hypothalamic neurogenesis, caused in adolescent male offspring twofold increase in drinking of and preference for ethanol and reinstatement of ethanol drinking in a two-bottle choice paradigm under an intermittent access schedule. This effect of prenatal ethanol exposure was associated with an increased expression of MCH and density of MCH(+) neurons in LH of preadolescent offspring. Whereas CCL2(+) cells at this age were low in density and unaffected by ethanol, CCR2(+) cells were dense in LH and increased by prenatal ethanol, with a large percentage (83-87%) identified as neurons and found to colocalize MCH. Prenatal ethanol also stimulated the genesis of CCR2(+) and MCH(+) neurons in the embryo, which co-labeled the proliferation marker, BrdU. Ethanol also increased the genesis and density of neurons that co-expressed CCR2 and MCH in LH, with triple-labeled CCR2(+)/MCH(+)/BrdU(+) neurons that were absent in control rats accounting for 35% of newly generated neurons in ethanol-exposed rats. With both the chemokine and MCH systems believed to promote ethanol consumption, this greater density of CCR2(+)/MCH(+) neurons in the LH of preadolescent rats suggests that

  19. The carboxyl terminus of the chemokine receptor CCR3 contains distinct domains which regulate chemotactic signaling and receptor down-regulation in a ligand-dependent manner.

    PubMed

    Sabroe, Ian; Jorritsma, Annelies; Stubbs, Victoria E L; Xanthou, Georgina; Jopling, Louise A; Ponath, Paul D; Williams, Timothy J; Murphy, Philip M; Pease, James E

    2005-04-01

    The chemokine receptor CCR3 regulates the chemotaxis of leukocytes implicated in allergic disease, such as eosinophils. Incubation of eosinophils with CCL11, CCL13 or CCL5 resulted in a rapid decrease of cell-surface CCR3 which was replicated using CCR3 transfectants. Progressive truncation of the CCR3 C terminus by 15 amino acids produced three constructs, Delta340, Delta325 and Delta310. Delta340 and Delta325 were able to bind CCL11 with affinities similar to wild-type CCR3. Delta340 transfectants exhibited enhanced migration and reduced receptor down-regulation in response to CCL11 and CCL13. Delta325 transfectants displayed chemotactic responses to CCL11 and CCL13 similar to wild-type CCR3, and had impaired down-regulation when stimulated with CCL13 but not CCL11. In contrast, neither the Delta325 nor Delta340 truncation affected chemotaxis or receptor down-regulation induced by CCL5. Delta310 transfectants bound CCL11 poorly and were biologically inactive. Inhibitors of p38 mitogen-activated protein kinase and PI3-kinase antagonized eosinophil shape change responses and chemotaxis of transfectants to CCL11 and CCL13. In contrast, shape change but not chemotaxis was sensitive to inhibition of the extracellular signal-regulated kinase kinase pathway suggesting differential regulation of the two responses. Thus, the CCR3 C terminus contains distinct domains responsible for the regulation of receptor desensitization and for coupling to chemotactic responses.

  20. Chemokines and immunity

    PubMed Central

    Palomino, Diana Carolina Torres; Marti, Luciana Cavalheiro

    2015-01-01

    Chemokines are a large family of small cytokines and generally have low molecular weight ranging from 7 to 15kDa. Chemokines and their receptors are able to control the migration and residence of all immune cells. Some chemokines are considered pro-inflammatory, and their release can be induced during an immune response at a site of infection, while others are considered homeostatic and are involved in controlling of cells migration during tissue development or maintenance. The physiologic importance of this family of mediators is resulting from their specificity − members of the chemokine family induce recruitment of well-defined leukocyte subsets. There are two major chemokine sub-families based upon cysteine residues position: CXC and CC. As a general rule, members of the CXC chemokines are chemotactic for neutrophils, and CC chemokines are chemotactic for monocytes and sub-set of lymphocytes, although there are some exceptions. This review discusses the potential role of chemokines in inflammation focusing on the two best-characterized chemokines: monocyte chemoattractant protein-1, a CC chemokine, and interleukin-8, a member of the CXC chemokine sub-family. PMID:26466066

  1. Increased Levels of C-C Chemokine RANTES in Asbestos Exposed Workers and in Malignant Mesothelioma Patients from an Hyperendemic Area

    PubMed Central

    Comar, Manola; Zanotta, Nunzia; Bonotti, Alessandra; Tognon, Mauro; Negro, Corrado; Cristaudo, Alfonso; Bovenzi, Massimo

    2014-01-01

    Background Asbestos-induced mesothelial inflammatory processes are thought to be the basic mechanisms underlying Malignant Mesothelioma (MM) development. Detection of MM often occurs at late stage due to the long and unpredictable latent period and the low incidence in asbestos exposed individuals. The aim of this study was to investigate early immunological biomarkers to characterize the prognostic profile of a possible asbestos-induced disease, in subjects from a MM hyperendemic area. Methods The Luminex Multiplex Panel Technology was used for the simultaneous measurement of serum levels of a large panel of 47 analytes, including cytokines and growth factors, from workers previously exposed to asbestos (Asb-workers), asbestos-induced MM patients and healthy subjects. In addition, to explore the influence on serum cytokines profile exerted by SV40 infection, a cofactor in MM development, a quantitative real time PCR was performed for sequences detection in the N-terminal and intronic regions of the SV40 Tag gene. Statistical analysis was done by means of the Mann-Whitney test and the Kruskall-Wallis test for variance analysis. Results A variety of 25 cytokines linked to pulmonary inflammation and tumor development were found significantly associated with Asb-workers and MM patients compared with healthy controls. A specific pattern of cytokines were found highly expressed in Asb-workers: IFN-alpha (p<0.05), EOTAXIN (p<0.01), RANTES (p<0.001), and in MM patients: IL-12(p40), IL-3, IL-1 alpha, MCP-3, beta-NGF, TNF-beta, RANTES (p<0.001). Notably, the chemokine RANTES measured the highest serum level showing an increased gradient of concentration from healthy subjects to Asb-workers and MM patients (p<0.001), independently of SV40 infection. Conclusion This study shows that, in subjects from an hyperendemic area for MM, the C-C chemokine RANTES is associated with the exposure to asbestos fibres. If validated in larger samples, this factor could have the potential to

  2. Interactions between Chemokines

    PubMed Central

    Cook, Anna; Hippensteel, Randi; Shimizu, Saori; Nicolai, Jaclyn; Fatatis, Alessandro; Meucci, Olimpia

    2010-01-01

    The soluble form of the chemokine fractalkine/CX3CL1 regulates microglia activation in the central nervous system (CNS), ultimately affecting neuronal survival. This study aims to determine whether CXCL12, another chemokine constitutively expressed in the CNS (known as stromal cell-derived factor 1; SDF-1), regulates cleavage of fractalkine from neurons. To this end, ELISA was used to measure protein levels of soluble fractalkine in the medium of rat neuronal cultures exposed to SDF-1. Gene arrays, quantitative RT-PCR, and Western blot were used to measure overall fractalkine expression in neurons. The data show that the rate of fractalkine shedding in healthy cultures positively correlates with in vitro differentiation and survival. In analogy to non-neuronal cells, metalloproteinases (ADAM10/17) are involved in cleavage of neuronal fractalkine as indicated by studies with pharmacologic inhibitors. Moreover, treatment of the neuronal cultures with SDF-1 stimulates expression of the inducible metalloproteinase ADAM17 and increases soluble fractalkine content in culture medium. The effect of SDF-1 is blocked by an inhibitor of both ADAM10 and -17, but only partially affected by a more specific inhibitor of ADAM10. In addition, SDF-1 also up-regulates expression of the fractalkine gene. Conversely, exposure of neurons to an excitotoxic stimulus (i.e. NMDA) inhibits α-secretase activity and markedly diminishes soluble fractalkine levels, leading to cell death. These results, along with previous findings on the neuroprotective role of both SDF-1 and fractalkine, suggest that this novel interaction between the two chemokines may contribute to in vivo regulation of neuronal survival by modulating microglial neurotoxic properties. PMID:20124406

  3. Interplay between signaling via the formyl peptide receptor (FPR) and chemokine receptor 3 (CCR3) in human eosinophils.

    PubMed

    Svensson, Lena; Redvall, Elin; Johnsson, Marianne; Stenfeldt, Anna-Lena; Dahlgren, Claes; Wennerås, Christine

    2009-08-01

    Eosinophils express the chemoattractant receptors CCR3 and FPR. CCR3 binds several agonists such as eotaxin-1, -2, and -3 and RANTES, whereas the FPR binds the formylated tripeptide fMLP and a host of other ligands. The aim of this study was to investigate if there is interplay between these two receptors regarding the elicitation of migration and respiratory burst in human blood-derived eosinophils. Inhibition of the FPR with the antagonists CyH and boc-MLP abrogated the migration of eosinophils toward all of the CCR3 agonists. Similar results were seen when the FPR was desensitized with its cognate ligand, fMLP. In contrast, the respiratory burst triggered by eotaxin-1 was not inhibited by CyH. Thus, signals evoked via the FPR caused unidirectional down-regulation of CCR3-mediated chemotaxis but not respiratory burst in human eosinophils. The underlying mechanism was neither reduced ability of the CCR3 ligand eotaxin-1 to bind to CCR3 nor down-regulation of CCR3 from the cell surface. Finally, confocal microscopy and adFRET analysis ruled out homo- or heterodimer formation between FPR and/or CCR3 as an explanation for the reduction in chemotaxis via CCR3. Pharmacologic inhibition of signal transduction molecules showed that the release of free oxygen radicals in response to eotaxin-1 compared with fMLP is relatively more dependent on the p38 MAPK pathway.

  4. Cytokine-induced sleep: Neurons respond to TNF with production of chemokines and increased expression of Homer1a in vitro.

    PubMed

    Karrer, Maureen; Lopez, Martin Alexander; Meier, Daniel; Mikhail, Cyril; Ogunshola, Omolara O; Müller, Andreas Felix; Strauss, Laura; Tafti, Mehdi; Fontana, Adriano

    2015-07-01

    Interactions of neurons with microglia may play a dominant role in sleep regulation. TNF may exert its somnogeneic effects by promoting attraction of microglia and their processes to the vicinity of dendrites and synapses. We found TNF to stimulate neurons (i) to produce CCL2, CCL7 and CXCL10, chemokines acting on mononuclear phagocytes and (ii) to stimulate the expression of the macrophage colony stimulating factor (M-CSF/Csf1), which leads to elongation of microglia processes. TNF may also act on neurons by affecting the expression of genes essential in sleep-wake behavior. The neuronal expression of Homer1a mRNA, increases during spontaneous and enforced periods of wakefulness. Mice with a deletion of Homer1a show a reduced wakefulness with increased non-rapid eye movement (NREM) sleep during the dark period. Recently the TNF-dependent increase of NREM sleep in the dark period of mice with CD40-induced immune activation was found to be associated with decreased expression of Homer1a. In the present study we investigated the effects of TNF and IL-1β on gene expression in cultures of the neuronal cell line HT22 and cortical neurons. TNF slightly increased the expression of Homer1a and IL-1β profoundly enhanced the expression of Early growth response 2 (Egr2). The data presented here indicate that the decreased expression of Homer1a, which was found in the dark period of mice with CD40-induced increase of NREM sleep is not due to inhibitory effects of TNF and IL-1β on the expression of Homer1a in neurons.

  5. Association of MIF, but not type I interferon-induced chemokines, with increased disease activity in Asian patients with systemic lupus erythematosus.

    PubMed

    Connelly, K L; Kandane-Rathnayake, R; Hoi, A; Nikpour, Mandana; Morand, E F

    2016-07-25

    Ethnicity is a key factor impacting on disease severity in SLE, but molecular mechanisms of these associations are unknown. Type I IFN and MIF have each been associated with SLE pathogenesis. We investigated whether increased SLE severity in Asian patients is associated with either MIF or Type I IFN. SLE patients (n = 151) had prospective recording of disease variables. Serum MIF, and a validated composite score of three Type I IFN-inducible chemokines (IFNCK:CCL2, CXCL10, CCL19) were measured. Associations of MIF and IFNCK score with disease activity were assessed, with persistent active disease (PAD) used as a marker of high disease activity over a median 2.6 years follow up. In univariable analysis, MIF, IFNCK score and Asian ethnicity were significantly associated with PAD. Asian ethnicity was associated with higher MIF but not IFNCK score. In multivariable logistic regression analysis, MIF (OR3.62 (95% CI 1.14,11.5), p = 0.03) and Asian ethnicity (OR3.00 (95% CI 1.39,6.46), p < 0.01) but not IFNCK were significantly associated with PAD. These results potentially support an effect of MIF, but not Type I IFN, in heightened SLE disease severity in Asian SLE. The associations of MIF and Asian ethnicity with PAD are at least partly independent.

  6. Overexpression of the Monocyte Chemokine CCL2 in Dorsal Root Ganglion Neurons Causes a Conditioning-Like Increase in Neurite Outgrowth and Does So via a STAT3 Dependent Mechanism

    PubMed Central

    Niemi, Jon P.; DeFrancesco-Lisowitz, Alicia; Cregg, Jared; Howarth, Madeline; Zigmond, Richard E.

    2015-01-01

    Neuroinflammation plays a critical role in the regeneration of peripheral nerves following axotomy. An injury to the sciatic nerve leads to significant macrophage accumulation in the L5 DRG, an effect not seen when the dorsal root is injured. We recently demonstrated that this accumulation around axotomized cell bodies is necessary for a peripheral conditioning lesion response to occur. Here we asked whether overexpression of the monocyte chemokine CCL2 specifically in DRG neurons of uninjured mice is sufficient to cause macrophage accumulation and to enhance regeneration or whether other injury-derived signals are required. AAV5-EF1α-CCL2 was injected intrathecally, and this injection led to a time-dependent increase in CCL2 mRNA expression and macrophage accumulation in L5 DRG, with a maximal response at 3 wk post-injection. These changes led to a conditioning-like increase in neurite outgrowth in DRG explant and dissociated cell cultures. This increase in regeneration was dependent upon CCL2 acting through its primary receptor CCR2. When CCL2 was overexpressed in CCR2 −/− mice, macrophage accumulation and enhanced regeneration were not observed. To address the mechanism by which CCL2 overexpression enhances regeneration, we tested for elevated expression of regeneration-associated genes in these animals. Surprisingly, we found that CCL2 overexpression led to a selective increase in LIF mRNA and neuronal phosphorylated STAT3 (pSTAT3) in L5 DRGs, with no change in expression seen in other RAGs such as GAP-43. Blockade of STAT3 phosphorylation by each of two different inhibitors prevented the increase in neurite outgrowth. Thus, CCL2 overexpression is sufficient to induce macrophage accumulation in uninjured L5 DRGs and increase the regenerative capacity of DRG neurons via a STAT3-dependent mechanism. PMID:26431741

  7. Costly Signaling Increases Trust, Even Across Religious Affiliations.

    PubMed

    Hall, Deborah L; Cohen, Adam B; Meyer, Kaitlin K; Varley, Allison H; Brewer, Gene A

    2015-09-01

    Trust is a critical aspect of social interaction. One might predict that individuals trust religious out-groups less than religious in-groups, and that costly signals performed by members of religious in-groups increase trust while costly signals performed by members of religious out-groups decrease trust. We examined how Christian participants perceived the trustworthiness of Muslim and Christian individuals who did or did not engage in religious costly signaling. Religious costly signaling, operationalized as giving to religious charities (Experiments 1 and 2) or adhering to religious dietary restrictions (Experiment 3), increased self-reported trust, regardless of target religious affiliation. Furthermore, when estimating the likelihood that trustworthy versus untrustworthy targets engaged in costly signaling, participants made systematic judgments that showed that costly signaling is associated with trust for both Muslim and Christian targets (Experiment 4). These results are novel in their suggestion that costly signals of religious commitment can increase trust both within and, crucially, across religious-group lines.

  8. Chemokines and chemokine receptors: standing at the crossroads of immunobiology and neurobiology.

    PubMed

    Ransohoff, Richard M

    2009-11-20

    There are several molecular entities common to the immune and nervous systems. Salient among them are the chemokines and their receptors, which play remarkably varied and potent roles in immunobiology and neurobiology. This review limns several illustrative examples and presents general principles of chemokine action that are manifest in both systems. These include the following: (1) chemokines tend equally to arrest cells and to make them move, in the process of positioning target cells with spatiotemporal precision; (2) signaling and nonsignaling receptors collaborate to adjust the chemokine environment for maximal efficacy; and (3) expression of a single chemokine receptor on circulating blood cells and parenchymal cells is often used to coordinate complex tissue responses. The challenge is to integrate knowledge of the roles of key receptors (as well as their ligands) into a coherent account of events during pathologic processes, in order to guide therapeutic development.

  9. Dysregulated Chemokine Receptor Expression and Chemokine-Mediated Cell Trafficking in Pediatric Patients with ESRD

    PubMed Central

    Sherry, Barbara; Dai, Wei Wei; Lesser, Martin L.; Trachtman, Howard

    2008-01-01

    Background and objectives: Children and adolescents with ESRD on dialysis are susceptible to serious bacterial infections (SBI). Chemokines and chemokine receptors play a critical role in modulating macrophage and neutrophil function. This study examined the hypothesis that expression and/or function of these molecules is dysregulated in patients with ESRD, contributing to leukocyte dysfunction. Design setting, participants, & measurements: Pediatric patients, age 6 mo to 18 yr, with ESRD treated with either hemodialysis or peritoneal dialysis were enrolled in this prospective, nontherapeutic study. Blood was collected for plasma chemokine levels, chemokine receptor profiling by flow cytometry, and functional chemotaxis studies on neutrophils and mononuclear cells. Results: ESRD in children was associated with reduced expression of the chemokine receptors CXCR1 and chemokine (C-C motif) receptor 2 (CCR2) on circulating neutrophils and monocytes, respectively. When ESRD patients were divided into two subgroups, those who were infection-free and those who had three or more SBI in the preceding year, the differences in chemokine receptor expression were statistically significant compared with control subjects only in those with recurrent infection. In addition to the effects of ESRD on baseline chemokine receptor expression, the hemodialysis procedure itself acutely lowered neutrophil CXCR1 and monocyte CCR2 expression. Furthermore, neutrophil and monocyte responsiveness to chemokine-mediated trafficking signals was impaired in all ESRD patients studied. This abnormality was independent of the level of chemokine receptor expression on the leukocytes. Conclusions: The data presented in this study suggest that chemokine receptor dysregulation contributes to leukocyte dysfunction in patients with ESRD. This alteration is especially prominent in ESRD patients with recurrent infection. PMID:18235145

  10. Chemokines, chemokine receptors and the gastrointestinal system

    PubMed Central

    Miyazaki, Hiroshi; Takabe, Kazuaki; Yeudall, W Andrew

    2013-01-01

    The biological properties of tumor cells are known to be regulated by a multitude of cytokines and growth factors, which include epidermal growth factor receptor agonists and members of the transforming growth factor β family. Furthermore, the recent explosion of research in the field of chemokine function as mediators of tumor progression has led to the possibility that these small, immunomodulatory proteins also play key roles in carcinogenesis and may, therefore, be potential targets for novel therapeutic approaches. In this review, we will summarize recently reported findings in chemokine biology with a focus on the gastrointestinal tract. PMID:23704819

  11. A novel highly potent therapeutic antibody neutralizes multiple human chemokines and mimics viral immune modulation.

    PubMed

    Scalley-Kim, Michelle L; Hess, Bruce W; Kelly, Ryan L; Krostag, Anne-Rachel F; Lustig, Kurt H; Marken, John S; Ovendale, Pamela J; Posey, Aaron R; Smolak, Pamela J; Taylor, Janelle D L; Wood, C L; Bienvenue, David L; Probst, Peter; Salmon, Ruth A; Allison, Daniel S; Foy, Teresa M; Raport, Carol J

    2012-01-01

    Chemokines play a key role in leukocyte recruitment during inflammation and are implicated in the pathogenesis of a number of autoimmune diseases. As such, inhibiting chemokine signaling has been of keen interest for the development of therapeutic agents. This endeavor, however, has been hampered due to complexities in the chemokine system. Many chemokines have been shown to signal through multiple receptors and, conversely, most chemokine receptors bind to more than one chemokine. One approach to overcoming this complexity is to develop a single therapeutic agent that binds and inactivates multiple chemokines, similar to an immune evasion strategy utilized by a number of viruses. Here, we describe the development and characterization of a novel therapeutic antibody that targets a subset of human CC chemokines, specifically CCL3, CCL4, and CCL5, involved in chronic inflammatory diseases. Using a sequential immunization approach, followed by humanization and phage display affinity maturation, a therapeutic antibody was developed that displays high binding affinity towards the three targeted chemokines. In vitro, this antibody potently inhibits chemotaxis and chemokine-mediated signaling through CCR1 and CCR5, primary chemokine receptors for the targeted chemokines. Furthermore, we have demonstrated in vivo efficacy of the antibody in a SCID-hu mouse model of skin leukocyte migration, thus confirming its potential as a novel therapeutic chemokine antagonist. We anticipate that this antibody will have broad therapeutic utility in the treatment of a number of autoimmune diseases due to its ability to simultaneously neutralize multiple chemokines implicated in disease pathogenesis.

  12. Chemical intervention in plant sugar signalling increases yield and resilience

    NASA Astrophysics Data System (ADS)

    Griffiths, Cara A.; Sagar, Ram; Geng, Yiqun; Primavesi, Lucia F.; Patel, Mitul K.; Passarelli, Melissa K.; Gilmore, Ian S.; Steven, Rory T.; Bunch, Josephine; Paul, Matthew J.; Davis, Benjamin G.

    2016-12-01

    The pressing global issue of food insecurity due to population growth, diminishing land and variable climate can only be addressed in agriculture by improving both maximum crop yield potential and resilience. Genetic modification is one potential solution, but has yet to achieve worldwide acceptance, particularly for crops such as wheat. Trehalose-6-phosphate (T6P), a central sugar signal in plants, regulates sucrose use and allocation, underpinning crop growth and development. Here we show that application of a chemical intervention strategy directly modulates T6P levels in planta. Plant-permeable analogues of T6P were designed and constructed based on a ‘signalling-precursor’ concept for permeability, ready uptake and sunlight-triggered release of T6P in planta. We show that chemical intervention in a potent sugar signal increases grain yield, whereas application to vegetative tissue improves recovery and resurrection from drought. This technology offers a means to combine increases in yield with crop stress resilience. Given the generality of the T6P pathway in plants and other small-molecule signals in biology, these studies suggest that suitable synthetic exogenous small-molecule signal precursors can be used to directly enhance plant performance and perhaps other organism function.

  13. The structural role of receptor tyrosine sulfation in chemokine recognition

    PubMed Central

    Ludeman, Justin P; Stone, Martin J

    2014-01-01

    Tyrosine sulfation is a post-translational modification of secreted and transmembrane proteins, including many GPCRs such as chemokine receptors. Most chemokine receptors contain several potentially sulfated tyrosine residues in their extracellular N-terminal regions, the initial binding site for chemokine ligands. Sulfation of these receptors increases chemokine binding affinity and potency. Although receptor sulfation is heterogeneous, insights into the molecular basis of sulfotyrosine (sTyr) recognition have been obtained using purified, homogeneous sulfopeptides corresponding to the N-termini of chemokine receptors. Receptor sTyr residues bind to a shallow cleft defined by the N-loop and β3-strand elements of cognate chemokines. Tyrosine sulfation enhances the affinity of receptor peptides for cognate chemokines in a manner dependent on the position of sulfation. Moreover, tyrosine sulfation can alter the selectivity of receptor peptides among several cognate chemokines for the same receptor. Finally, binding to receptor sulfopeptides can modulate the oligomerization state of chemokines, thereby influencing the ability of a chemokine to activate its receptor. These results increase the motivation to investigate the structural basis by which tyrosine sulfation modulates chemokine receptor activity and the biological consequences of this functional modulation. Linked ArticlesThis article is part of a themed section on Molecular Pharmacology of GPCRs. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-5 PMID:24116930

  14. Chemokines and their receptors in central nervous system disease.

    PubMed

    Biber, Knut; de Jong, Eiko K; van Weering, Hilmar R J; Boddeke, Hendrikus W G M

    2006-01-01

    Almost a decade ago, it was discovered that the human deficiency virus (HIV) makes use of chemokine receptors to infect blood cells. This appreciation of the clinical relevance of specific chemokine receptors has initiated a considerable boost in the field of chemokine research. It is clear today that chemokine signaling orchestrates the immune system and is widely involved in both physiological and pathophysiological processes. Since the chemokine system offers various targets through which pathology could be influenced, most pharmaceutical companies have chosen this system as a therapeutic target for a variety of diseases. Here recent developments concerning the role of chemokines in diseases of the central nervous system (CNS) as well as their possible therapeutic relevance are discussed.

  15. Dysregulation of Chemokine/Chemokine Receptor Axes and NK Cell Tissue Localization during Diseases.

    PubMed

    Bernardini, Giovanni; Antonangeli, Fabrizio; Bonanni, Valentina; Santoni, Angela

    2016-01-01

    Chemokines are small chemotactic molecules that play key roles in physiological and pathological conditions. Upon signaling via their specific receptors, chemokines regulate tissue mobilization and trafficking of a wide array of immune cells, including natural killer (NK) cells. Current research is focused on analyzing changes in chemokine/chemokine receptor expression during various diseases to interfere with pathological trafficking of cells or to recruit selected cell types to specific tissues. NK cells are a heterogeneous lymphocyte population comprising several subsets endowed with distinct functional properties and mainly representing distinct stages of a linear development process. Because of their different functional potential, the type of subset that accumulates in a tissue drives the final outcome of NK cell-regulated immune response, leading to either protection or pathology. Correspondingly, chemokine receptors, including CXCR4, CXCR3, and CX3CR1, are differentially expressed by NK cell subsets, and their expression levels can be modulated during NK cell activation. At first, this review will summarize the current knowledge on the contribution of chemokines to the localization and generation of NK cell subsets in homeostasis. How an inappropriate chemotactic response can lead to pathology and how chemokine targeting can therapeutically affect tissue recruitment/localization of distinct NK cell subsets will also be discussed.

  16. Dysregulation of Chemokine/Chemokine Receptor Axes and NK Cell Tissue Localization during Diseases

    PubMed Central

    Bernardini, Giovanni; Antonangeli, Fabrizio; Bonanni, Valentina; Santoni, Angela

    2016-01-01

    Chemokines are small chemotactic molecules that play key roles in physiological and pathological conditions. Upon signaling via their specific receptors, chemokines regulate tissue mobilization and trafficking of a wide array of immune cells, including natural killer (NK) cells. Current research is focused on analyzing changes in chemokine/chemokine receptor expression during various diseases to interfere with pathological trafficking of cells or to recruit selected cell types to specific tissues. NK cells are a heterogeneous lymphocyte population comprising several subsets endowed with distinct functional properties and mainly representing distinct stages of a linear development process. Because of their different functional potential, the type of subset that accumulates in a tissue drives the final outcome of NK cell-regulated immune response, leading to either protection or pathology. Correspondingly, chemokine receptors, including CXCR4, CXCR3, and CX3CR1, are differentially expressed by NK cell subsets, and their expression levels can be modulated during NK cell activation. At first, this review will summarize the current knowledge on the contribution of chemokines to the localization and generation of NK cell subsets in homeostasis. How an inappropriate chemotactic response can lead to pathology and how chemokine targeting can therapeutically affect tissue recruitment/localization of distinct NK cell subsets will also be discussed. PMID:27766097

  17. Chemokines and chemokine receptors in chronic lymphocytic leukemia (CLL): from understanding the basics towards therapeutic targeting.

    PubMed

    Burger, Jan A

    2010-12-01

    Chemokines and their receptors organize the recruitment and positioning of cells at each stage of the immune response, a system critically dependent upon coordination to get the right cells to the right place at the right time. Chemokine receptors expressed on CLL B cells are thought to function in a similar fashion, regulating the trafficking of the leukemia cells between blood, lymphoid organs, and the bone marrow, and within sub compartments within these tissues, in concert with adhesion molecules and other guidance cues. CLL cells not only respond to chemokines secreted in the microenvironment, the leukemia cells also secrete chemokines in response to external signals, such as B cell receptor engagement. These CLL cell-derived chemokines facilitate interactions between CLL cells, T cells, and other immune cells that shape the CLL microenvironment. CXCR4, the most prominent chemokine receptor in CLL, is now targeted in a first clinical trial, emphasizing that chemokines and their receptors have become a highly dynamic translational research field.

  18. Chemokine CXCL12 uses CXCR4 and a signaling core formed by bifunctional Akt, extracellular signal-regulated kinase (ERK)1/2, and mammalian target of rapamycin complex 1 (mTORC1) proteins to control chemotaxis and survival simultaneously in mature dendritic cells.

    PubMed

    Delgado-Martín, Cristina; Escribano, Cristina; Pablos, José Luis; Riol-Blanco, Lorena; Rodríguez-Fernández, José Luis

    2011-10-28

    Chemokines control several cell functions in addition to chemotaxis. Although much information is available on the involvement of specific signaling molecules in the control of single functions controlled by chemokines, especially chemotaxis, the mechanisms used by these ligands to regulate several cell functions simultaneously are completely unknown. Mature dendritic cells (maDCs) migrate through the afferent lymphatic vessels to the lymph nodes, where they regulate the initiation of the immune response. As maDCs are exposed to chemokine CXCL12 (receptors CXCR4 and CXCR7) during their migration, its functions are amenable to be regulated by this ligand. We have used maDCs as a model system to analyze the mechanisms whereby CXCL12 simultaneously controls chemotaxis and survival in maDCs. We show that CXCL12 uses CXCR4, but not CXCR7, and the components of a signaling core that includes G(i)/Gβγ, PI3K-α/-δ/-γ, Akt, ERK1/2 and mammalian target of rapamycin complex 1 (mTORC1), which organize hierarchically to control both functions. Downstream of Akt, Forkhead box class O (FOXO) regulates CXCL12-dependent survival, but not chemotaxis, suggesting that downstream of the aforementioned signaling core, additional signaling molecules may control more selectively CXCL12-dependent chemotaxis or survival. Finally, the data obtained also show that CXCR4 uses a signaling signature that is different from that used by CCR7 to control similar functions.

  19. Subsets of myeloid-derived suppressor cells in hepatocellular carcinoma express chemokines and chemokine receptors differentially.

    PubMed

    Zhao, Wenxiu; Xu, Yaping; Xu, Jianfeng; Wu, Duan; Zhao, Bixing; Yin, Zhenyu; Wang, Xiaomin

    2015-06-01

    Tumors induce the recruitment and expansion of myeloid-derived suppressor cells (MDSCs), a heterogeneous population of cells that can be further sub-divided into polymorphonuclear Ly6G(+) PMN-MDSCs and monocytic Ly6G(-) Mo-MDSCs. To identify chemokines and chemokine-related genes that are differentially expressed within the tumor microenvironment in these two MDSC subsets, we established an orthotopic hepatocellular carcinoma model in immunocompetent mice. Splenic PMN-MDSCs and Mo-MDSCs were isolated to >95% homogeneity by flow cytometry. Using a real-time PCR array, we investigated the expression of 84 genes encoding chemokines and cytokines, chemokine receptors, and related signaling molecules involved with chemotaxis. Clustering analysis suggested that a core set of chemokine-related genes is expressed in both PMN-MDSC and Mo-MDSC populations, but that the expression profile is broader for Mo-MDSCs. Furthermore, 11 genes are more highly expressed in PMN-MDSCs and 12 genes are more highly expressed in Mo-MDSCs. Among these, PMN-MDSCs express Cxcr1, Cxcr2 and Il1b at 33.03- to 109.76-fold higher levels than in Mo-MDSCs, and Mo-MDSCs express eight genes (Ccr2, Ccr5, Cmklr1, Cx3cr1, Ccr3, Ccl9, Cmtm3 and Cxcl16) at 30.2 to 515.5-fold higher levels than in PMN-MDSCs. These results suggest that the profile of chemokines and chemokine-related genes is more expansive for Mo-MDSCs than for PMN-MDSCs. The differential expression of chemokines and chemokine-associated genes may regulate the presence and activity of PMN-MDSCs and Mo-MDSCs in the tumor microenvironment.

  20. Chemokines and other GPCR ligands synergize in receptor-mediated migration of monocyte-derived immature and mature dendritic cells.

    PubMed

    Gouwy, Mieke; Struyf, Sofie; Leutenez, Lien; Pörtner, Noëmie; Sozzani, Silvano; Van Damme, Jo

    2014-03-01

    Dendritic cells (DCs) are potent antigen presenting cells, described as the initiators of adaptive immune responses. Immature monocyte-derived DCs (MDDC) showed decreased CD14 expression, increased cell surface markers DC-SIGN and CD1a and enhanced levels of receptors for the chemokines CCL3 (CCR1/CCR5) and CXCL8 (CXCR1/CXCR2) compared with human CD14⁺ monocytes. After further MDDC maturation by LPS, the markers CD80 and CD83 and the chemokine receptors CXCR4 and CCR7 were upregulated, whereas CCR1, CCR2 and CCR5 expression was reduced. CCL3 dose-dependently synergized with CXCL8 or CXCL12 in chemotaxis of immature MDDC. CXCL12 augmented the CCL3-induced ERK1/2 and Akt phosphorylation in immature MDDC, although the synergy between CCL3 and CXCL12 in chemotaxis of immature MDDC was dependent on the Akt signaling pathway but not on ERK1/2 phosphorylation. CCL2 also synergized with CXCL12 in immature MDDC migration. Moreover, two CXC chemokines not sharing receptors (CXCL12 and CXCL8) cooperated in immature MDDC chemotaxis, whereas two CC chemokines (CCL3 and CCL7) sharing CCR1 did not. Further, the non-chemokine G protein-coupled receptor ligands chemerin and fMLP synergized with respectively CCL7 and CCL3 in immature MDDC signaling and migration. Finally, CXCL12 and CCL3 did not cooperate, but CXCL12 synergized with CCL21 in mature MDDC chemotaxis. Thus, chemokine synergy in immature and mature MDDC migration is dose-dependently regulated by chemokines via alterations in their chemokine receptor expression pattern according to their role in immune responses.

  1. Chemokine RANTES in atopic dermatitis.

    PubMed

    Glück, J; Rogala, B

    1999-01-01

    Chemokines play a key role in inflammatory diseases. The aim of this study was to estimate chemokine RANTES in the sera of patients with atopic dermatitis (AD) and to analyze the correlation between RANTES serum level and the immunological and clinical parameters of the disease. Serum levels of RANTES (ELISA; R&D Systems), total IgE and specific IgE (FEIA; Pharmacia CAP System) were estimated in 24 patients with AD, 28 patients with pollinosis (PL) and 22 healthy nonatopic subjects (HC). The division of the AD group into a pure AD (pAD) subgroup, without a coexisting respiratory allergy, and a subgroup of patients with AD and a respiratory allergy (AD+AO) was done according to Wütrich. Levels of RANTES were higher in the AD group than in the HC group and the PL group. RANTES levels did not differ among subgroups with various clinical scores and between the pAD and AD+AO subgroups. There were no correlations between levels of RANTES and total IgE. Significant positive correlations between serum levels of RANTES and Dermatophagoides farinae and cat dander-specific IgE were found in the AD group. We conclude that the serum level of chemokine RANTES differs patients with AD from patients with PL. The increase of RANTES concentration in the serum of patients with AD depends neither on a clinical picture nor an IgE system.

  2. Increased GABAB receptor signaling in a rat model for schizophrenia

    PubMed Central

    Selten, Martijn M.; Meyer, Francisca; Ba, Wei; Vallès, Astrid; Maas, Dorien A.; Negwer, Moritz; Eijsink, Vivian D.; van Vugt, Ruben W. M.; van Hulten, Josephus A.; van Bakel, Nick H. M.; Roosen, Joey; van der Linden, Robert J.; Schubert, Dirk; Verheij, Michel M. M.; Kasri, Nael Nadif; Martens, Gerard J. M.

    2016-01-01

    Schizophrenia is a complex disorder that affects cognitive function and has been linked, both in patients and animal models, to dysfunction of the GABAergic system. However, the pathophysiological consequences of this dysfunction are not well understood. Here, we examined the GABAergic system in an animal model displaying schizophrenia-relevant features, the apomorphine-susceptible (APO-SUS) rat and its phenotypic counterpart, the apomorphine-unsusceptible (APO-UNSUS) rat at postnatal day 20–22. We found changes in the expression of the GABA-synthesizing enzyme GAD67 specifically in the prelimbic- but not the infralimbic region of the medial prefrontal cortex (mPFC), indicative of reduced inhibitory function in this region in APO-SUS rats. While we did not observe changes in basal synaptic transmission onto LII/III pyramidal cells in the mPFC of APO-SUS compared to APO-UNSUS rats, we report reduced paired-pulse ratios at longer inter-stimulus intervals. The GABAB receptor antagonist CGP 55845 abolished this reduction, indicating that the decreased paired-pulse ratio was caused by increased GABAB signaling. Consistently, we find an increased expression of the GABAB1 receptor subunit in APO-SUS rats. Our data provide physiological evidence for increased presynaptic GABAB signaling in the mPFC of APO-SUS rats, further supporting an important role for the GABAergic system in the pathophysiology of schizophrenia. PMID:27687783

  3. Increased GABAB receptor signaling in a rat model for schizophrenia.

    PubMed

    Selten, Martijn M; Meyer, Francisca; Ba, Wei; Vallès, Astrid; Maas, Dorien A; Negwer, Moritz; Eijsink, Vivian D; van Vugt, Ruben W M; van Hulten, Josephus A; van Bakel, Nick H M; Roosen, Joey; van der Linden, Robert J; Schubert, Dirk; Verheij, Michel M M; Kasri, Nael Nadif; Martens, Gerard J M

    2016-09-30

    Schizophrenia is a complex disorder that affects cognitive function and has been linked, both in patients and animal models, to dysfunction of the GABAergic system. However, the pathophysiological consequences of this dysfunction are not well understood. Here, we examined the GABAergic system in an animal model displaying schizophrenia-relevant features, the apomorphine-susceptible (APO-SUS) rat and its phenotypic counterpart, the apomorphine-unsusceptible (APO-UNSUS) rat at postnatal day 20-22. We found changes in the expression of the GABA-synthesizing enzyme GAD67 specifically in the prelimbic- but not the infralimbic region of the medial prefrontal cortex (mPFC), indicative of reduced inhibitory function in this region in APO-SUS rats. While we did not observe changes in basal synaptic transmission onto LII/III pyramidal cells in the mPFC of APO-SUS compared to APO-UNSUS rats, we report reduced paired-pulse ratios at longer inter-stimulus intervals. The GABAB receptor antagonist CGP 55845 abolished this reduction, indicating that the decreased paired-pulse ratio was caused by increased GABAB signaling. Consistently, we find an increased expression of the GABAB1 receptor subunit in APO-SUS rats. Our data provide physiological evidence for increased presynaptic GABAB signaling in the mPFC of APO-SUS rats, further supporting an important role for the GABAergic system in the pathophysiology of schizophrenia.

  4. Age-Associated Increase in BMP Signaling Inhibits Hippocampal Neurogenesis.

    PubMed

    Yousef, Hanadie; Morgenthaler, Adam; Schlesinger, Christina; Bugaj, Lukasz; Conboy, Irina M; Schaffer, David V

    2015-05-01

    Hippocampal neurogenesis, the product of resident neural stem cell proliferation and differentiation, persists into adulthood but decreases with organismal aging, which may contribute to the age-related decline in cognitive function. The mechanisms that underlie this decrease in neurogenesis are not well understood, although evidence in general indicates that extrinsic changes in an aged stem cell niche can contribute to functional decline in old stem cells. Bone morphogenetic protein (BMP) family members are intercellular signaling proteins that regulate stem and progenitor cell quiescence, proliferation, and differentiation in various tissues and are likewise critical regulators of neurogenesis in young adults. Here, we establish that BMP signaling increases significantly in old murine hippocampi and inhibits neural progenitor cell proliferation. Furthermore, direct in vivo attenuation of BMP signaling via genetic and transgenic perturbations in aged mice led to elevated neural stem cell proliferation, and subsequent neurogenesis, in old hippocampi. Such advances in our understanding of mechanisms underlying decreased hippocampal neurogenesis with age may offer targets for the treatment of age-related cognitive decline.

  5. Chemokines and skin diseases.

    PubMed

    Sugaya, Makoto

    2015-04-01

    Chemokines are small molecules that induce chemotaxis and activation of certain subsets of leukocytes. The expression patterns of chemokines and chemokine receptors are specific to certain organs and cells. Therefore, chemokines are important to elucidate the mechanism of organ-specific human diseases. CCL17 expressed by Langerhans cells, blood endothelial cells, and fibroblasts plays a key role in attracting Th2 cells and tumor cells of adult T-cell leukemia/lymphoma and mycosis fungoides/Sézary syndrome into the skin, developing various Th2-type inflammatory skin diseases as well as cutaneous lymphoma. CCL11 and CCL26 expressed by skin-resident cells, such as fibroblasts, blood endothelial cells, and keratinocytes, induce infiltration of CCR3-expressing cells such as Th2 cells and eosinophils. CCL11 may also serve as an autocrine as well as a paracrine in anaplastic large cell lymphoma. CX3CL1 expressed on blood endothelial cells leads to infiltration of CX3CR1(+) immune cells, such as mast cells, neutrophils, and macrophages, playing important roles in wound healing, tumor immunity, and vasculitis. Biologics targeting chemokines and their receptors are promising strategies for various skin diseases that are resistant to the current therapy.

  6. PMT signal increase using a wavelength shifting paint

    NASA Astrophysics Data System (ADS)

    Allada, K.; Hurlbut, Ch.; Ou, L.; Schmookler, B.; Shahinyan, A.; Wojtsekhowski, B.

    2015-05-01

    We report a 1.65 times increase of the PMT signal and a simple procedure of application of a new wavelength shifting (WLS) paint for PMTs with non-UV-transparent windows. Samples of four different WLS paints, made from hydrocarbon polymers and organic fluors, were tested on a 5-in. PMT (ET 9390KB) using Cherenkov radiation produced in fused silica disks by 106Ru electrons on a 'table-top' setup. The best performing paint was employed on two different types of 5-in. PMTs (ET 9390KB and XP4572B), installed in atmospheric pressure CO2 gas Cherenkov detectors, and tested using GeV electrons.

  7. Multiple Myeloma Impairs Bone Marrow Localization of Effector Natural Killer Cells by Altering the Chemokine Microenvironment.

    PubMed

    Ponzetta, Andrea; Benigni, Giorgia; Antonangeli, Fabrizio; Sciumè, Giuseppe; Sanseviero, Emilio; Zingoni, Alessandra; Ricciardi, Maria Rosaria; Petrucci, Maria Teresa; Santoni, Angela; Bernardini, Giovanni

    2015-11-15

    Natural killer (NK) cells are key innate immune effectors against multiple myeloma, their activity declining in multiple myeloma patients with disease progression. To identify the mechanisms underlying NK cell functional impairment, we characterized the distribution of functionally distinct NK cell subsets in the bone marrow of multiple myeloma-bearing mice. Herein we report that the number of KLRG1(-) NK cells endowed with potent effector function rapidly and selectively decreases in bone marrow during multiple myeloma growth, this correlating with decreased bone marrow NK cell degranulation in vivo. Altered NK cell subset distribution was dependent on skewed chemokine/chemokine receptor axes in the multiple myeloma microenvironment, with rapid downmodulation of the chemokine receptor CXCR3 on NK cells, increased CXCL9 and CXCL10, and decreased CXCL12 expression in bone marrow. Similar alterations in chemokine receptor/chemokine axes were observed in patients with multiple myeloma. Adoptive transfer experiments demonstrated that KLRG1(-) NK cell migration to the bone marrow was more efficient in healthy than multiple myeloma-bearing mice. Furthermore, bone marrow localization of transferred CXCR3-deficient NK cells with respect to wild type was enhanced in healthy and multiple myeloma-bearing mice, suggesting that CXCR3 restrains bone marrow NK cell trafficking. Our results indicate that multiple myeloma-promoted CXCR3 ligand upregulation together with CXCL12 downmodulation act as exit signals driving effector NK cells outside the bone marrow, thus weakening the antitumor immune response at the primary site of tumor growth.

  8. Cholesterol Depletion Alters Cardiomyocyte Subcellular Signaling and Increases Contractility

    PubMed Central

    McIntosh, Victoria J.; Abou Samra, Abdul B.; Mohammad, Ramzi M.; Lasley, Robert D.

    2016-01-01

    Membrane cholesterol levels play an important factor in regulating cell function. Sarcolemmal cholesterol is concentrated in lipid rafts and caveolae, which are flask-shaped invaginations of the plasma membrane. The scaffolding protein caveolin permits the enrichment of cholesterol in caveolae, and caveolin interactions with numerous proteins regulate their function. The purpose of this study was to determine whether acute reductions in cardiomyocyte cholesterol levels alter subcellular protein kinase activation, intracellular Ca2+ and contractility. Methods: Ventricular myocytes, isolated from adult Sprague Dawley rats, were treated with the cholesterol reducing agent methyl-β-cyclodextrin (MβCD, 5 mM, 1 hr, room temperature). Total cellular cholesterol levels, caveolin-3 localization, subcellular, ERK and p38 mitogen activated protein kinase (MAPK) signaling, contractility, and [Ca2+]i were assessed. Results: Treatment with MβCD reduced cholesterol levels by ~45 and shifted caveolin-3 from cytoskeleton and triton-insoluble fractions to the triton-soluble fraction, and increased ERK isoform phosphorylation in cytoskeletal, cytosolic, triton-soluble and triton-insoluble membrane fractions without altering their subcellular distributions. In contrast the primary effect of MβCD was on p38 subcellular distribution of p38α with little effect on p38 phosphorylation. Cholesterol depletion increased cardiomyocyte twitch amplitude and the rates of shortening and relaxation in conjunction with increased diastolic and systolic [Ca2+]i. Conclusions: These results indicate that acute reductions in membrane cholesterol levels differentially modulate basal cardiomyocyte subcellular MAPK signaling, as well as increasing [Ca2+]i and contractility. PMID:27441649

  9. Sexual signalling by females: do unmated females increase their signalling effort?

    PubMed Central

    Simmons, Leigh W.

    2015-01-01

    Theory predicts that females should invest least in mate searching when young, but increase their effort with age if they remain unmated. Few studies have examined variation in female sexual signalling. Female Dawson's burrowing bees (Amegilla dawsoni) search for males by signalling their receptivity on emergence, but many leave the emergence site unmated and must attract males at feeding sites. Female bees prevented from mating on emergence had more extreme versions of cuticular hydrocarbon profiles that make them attractive to males, lending empirical evidence of adaptive shifts in female mating effort. PMID:26109613

  10. Chemokines and chemokine receptors as promoters of prostate cancer growth and progression.

    PubMed

    Salazar, Nicole; Castellan, Miguel; Shirodkar, Samir S; Lokeshwar, Bal L

    2013-01-01

    Prostate cancer (CaP) is estimated to be first in incidence among cancers, with more than 240,000 new cases in 2012 in the United States. Chemokines and their receptors provide survival, proliferation, and invasion characteristics to CaP cells in both primary sites of cancer and metastatic locations. The emerging data demonstrate that many chemokines and their receptors are involved in the multistep process of CaP, leading to metastasis, and, further, that these factors act cooperatively to enhance other mechanisms of tumor cell survival, growth, and metastasis. Changes of chemokine receptor cohorts may be necessary to activate tumor-promoting signals. Chemokine receptors can activate downstream effectors, such as mitogen-activated protein kinases, by complex mechanisms of ligand-dependent activation of cryptic growth factors; guanosine triphosphate-binding, protein-coupled activation of survival kinases; or transactivation of other receptors such as ErbB family members. We describe vanguard research in which more than the classic view of chemokine receptor biology was clarified. Control of chemokines and inhibition of their receptor activation may add critical tools to reduce tumor growth, especially in chemo-hormonal refractory CaP that is both currently incurable and the most aggressive form of the disease, accounting for most of the more than 28,000 annual deaths.

  11. Chemokines in atherosclerosis: proceedings resumed.

    PubMed

    Zernecke, Alma; Weber, Christian

    2014-04-01

    Chemokines play important roles in atherosclerotic vascular disease. Expressed by not only cells of the vessel wall but also emigrated leukocytes, chemokines were initially discovered to direct leukocytes to sites of inflammation. However, chemokines can also exert multiple functions beyond cell recruitment. Here, we discuss novel and recently emerging aspects of chemokines and their involvement in atherosclerosis. While reviewing newly identified roles of chemokines and their receptors in monocyte and neutrophil recruitment during atherogenesis and atheroregression, we also revisit homeostatic functions of chemokines, including their roles in cell homeostasis and foam cell formation. The functional diversity of chemokines in atherosclerosis warrants a clear-cut mechanistic dissection and stage-specific assessment to better appreciate the full scope of their actions in vascular inflammation and to identify pathways that harbor the potential for a therapeutic targeting of chemokines in atherosclerosis.

  12. Chemokines and Chemokine Receptors in the Development of Lupus Nephritis

    PubMed Central

    2016-01-01

    Lupus nephritis (LN) is a major cause of morbidity and mortality in the patients with systemic lupus erythematosus (SLE), an autoimmune disease with damage to multiple organs. Leukocyte recruitment into the inflamed kidney is a critical step to promote LN progression, and the chemokine/chemokine receptor system is necessary for leukocyte recruitment. In this review, we summarize recent studies on the roles of chemokines and chemokine receptors in the development of LN and discuss the potential and hurdles of developing novel, chemokine-based drugs to treat LN. PMID:27403037

  13. Effects of chemokine receptor signalling on cognition-like, emotion-like and sociability behaviours of CCR6 and CCR7 knockout mice.

    PubMed

    Jaehne, E J; Baune, B T

    2014-03-15

    Inflammation is regarded as an important mechanism of neuropsychiatric disorders. Chemokines, which are a part of the immune system, have effects on various aspects of brain function, but little is known about their effects on behaviour. We have compared the cognition-like behaviour (learning and spatial memory) of CCR6(-/-) and CCR7(-/-) mice with wild type (WT) C57BL/6 mice, in the Barnes maze, as well as a range of other behaviours, including exploratory, anxiety and depression-like behaviour, using a battery of tests. Levels of cytokines TNF-α, IL-1β and IL-6 were also measured. In the Barnes maze, CCR7(-/-) mice were shown to take longer to learn the location of the escape box on the 1st of 4 days of training. In the behavioural battery, CCR6(-/-) mice showed higher locomotor activity and lower anxiety in the open field test, and a lack of preference for social novelty in a sociability test. CCR7(-/-) mice behaved much like WT mice, although showed higher anxiety in Elevated Zero Maze. While baseline saccharin preference in a 2-bottle choice test, a test for anhedonia depression-like behaviour, was equal in all strains at baseline, weekly tests showed that both CCR6(-/-) and CCR7(-/-) mice developed a decreased preference for saccharin compared to WT over time. There were no differences between strains in any of the cytokines measured. These results suggest that chemokine receptors may play a role in cognition and learning behaviour, as well as anxiety and other behaviours, although the biological mechanisms are still unclear.

  14. An atypical addition to the chemokine receptor nomenclature: IUPHAR Review 15.

    PubMed

    Bachelerie, Françoise; Graham, Gerard J; Locati, Massimo; Mantovani, Alberto; Murphy, Philip M; Nibbs, Robert; Rot, Antal; Sozzani, Silvano; Thelen, Marcus

    2015-08-01

    Chemokines and their receptors are essential regulators of in vivo leukocyte migration and, some years ago, a systematic nomenclature system was developed for the chemokine receptor family. Chemokine receptor biology and biochemistry was recently extensively reviewed. In this review, we also highlighted a new component to the nomenclature system that incorporates receptors previously known as 'scavenging', or 'decoy', chemokine receptors on the basis of their lack of classical signalling responses to ligand binding and their general ability to scavenge, or sequester, their cognate chemokine ligands. These molecules are now collectively referred to as 'atypical chemokine receptors', or ACKRs, and play fundamental roles in regulating in vivo responses to chemokines. This commentary highlights this new addition to the chemokine receptor nomenclature system and provides brief information on the four receptors currently covered by this nomenclature.

  15. An atypical addition to the chemokine receptor nomenclature: IUPHAR Review 15

    PubMed Central

    Bachelerie, Françoise; Graham, Gerard J; Locati, Massimo; Mantovani, Alberto; Murphy, Philip M; Nibbs, Robert; Rot, Antal; Sozzani, Silvano; Thelen, Marcus

    2015-01-01

    Chemokines and their receptors are essential regulators of in vivo leukocyte migration and, some years ago, a systematic nomenclature system was developed for the chemokine receptor family. Chemokine receptor biology and biochemistry was recently extensively reviewed. In this review, we also highlighted a new component to the nomenclature system that incorporates receptors previously known as ‘scavenging’, or ‘decoy’, chemokine receptors on the basis of their lack of classical signalling responses to ligand binding and their general ability to scavenge, or sequester, their cognate chemokine ligands. These molecules are now collectively referred to as ‘atypical chemokine receptors’, or ACKRs, and play fundamental roles in regulating in vivo responses to chemokines. This commentary highlights this new addition to the chemokine receptor nomenclature system and provides brief information on the four receptors currently covered by this nomenclature. PMID:25958743

  16. Multi-walled carbon nanotubes act as a chemokine and recruit macrophages by activating the PLC/IP3/CRAC channel signaling pathway.

    PubMed

    Li, Hui; Tan, Xiao-Qiu; Yan, Li; Zeng, Bo; Meng, Jie; Xu, Hai-Yan; Cao, Ji-Min

    2017-03-22

    The impact of nanomaterials on immune cells is gaining attention but is not well documented. Here, we report a novel stimulating effect of carboxylated multi-walled carbon nanotubes (c-MWCNTs) on the migration of macrophages and uncover the underlying mechanisms, especially the upstream signaling, using a series of techniques including transwell migration assay, patch clamp, ELISA and confocal microscopy. c-MWCNTs dramatically stimulated the migration of RAW264.7 macrophages when endocytosed, and this effect was abolished by inhibiting phospholipase C (PLC) with U-73122, antagonizing the IP3 receptor with 2-APB, and blocking calcium release-activated calcium (CRAC) channels with SK&F96365. c-MWCNTs directly activated PLC and increased the IP3 level and [Ca(2+)]i level in RAW264.7 cells, promoted the translocation of the ER-resident stromal interaction molecule 1 (STIM1) towards the membranous calcium release-activated calcium channel modulator 1 (Orai1), and increased CRAC current densities in both RAW264.7 cells and HEK293 cells stably expressing the CRAC channel subunits Orai1 and STIM1. c-MWCNTs also induced dramatic spatial polarization of KCa3.1 channels in the RAW264.7 cells. We conclude that c-MWCNT is an activator of PLC and strongly recruits macrophages via the PLC/IP3/CRAC channel signaling cascade. These novel findings may provide a fundamental basis for the impact of MWCNTs on the immune system.

  17. Pediatric patients with inflammatory bowel disease exhibit increased serum levels of proinflammatory cytokines and chemokines, but decreased circulating levels of macrophage inhibitory protein-1β, interleukin-2 and interleukin-17

    PubMed Central

    KLEINER, GIULIO; ZANIN, VALENTINA; MONASTA, LORENZO; CROVELLA, SERGIO; CARUSO, LORENZO; MILANI, DANIELA; MARCUZZI, ANNALISA

    2015-01-01

    Inflammatory bowel disease (IBD) is a chronic and progressive inflammatory condition of the gastrointestinal tract. Although the causative events that lead to the onset of IBD are yet to be fully elucidated, deregulation of immune and inflammatory mechanisms are hypothesized to significantly contribute to this disorder. Since the onset of IBD is often during infancy, in the present study, the serum values of a large panel of cytokines and chemokines in pediatric patients (<18 years; n=26) were compared with age-matched controls (n=37). While elevations in the serum level of several proinflammatory and immune regulating cytokines were confirmed, such as interleukin (IL)-1β, IL-5, IL-7, interferon (IFN)-γ-inducible protein-10, IL-16, cutaneous T-cell-attracting chemokine, leukemia inhibitory factor, monokine induced by γ-IFN, IFN-α2 and IFN-γ, notably decreased levels of IL-2, IL-17 and macrophage inhibitory protein-1β were also observed. Therefore, while a number of proinflammatory cytokines exhibit increased levels in IBD patients, pediatric IBD patients may also exhibit certain aspects of a reduced immunological response. PMID:26136934

  18. Pediatric patients with inflammatory bowel disease exhibit increased serum levels of proinflammatory cytokines and chemokines, but decreased circulating levels of macrophage inhibitory protein-1β, interleukin-2 and interleukin-17.

    PubMed

    Kleiner, Giulio; Zanin, Valentina; Monasta, Lorenzo; Crovella, Sergio; Caruso, Lorenzo; Milani, Daniela; Marcuzzi, Annalisa

    2015-06-01

    Inflammatory bowel disease (IBD) is a chronic and progressive inflammatory condition of the gastrointestinal tract. Although the causative events that lead to the onset of IBD are yet to be fully elucidated, deregulation of immune and inflammatory mechanisms are hypothesized to significantly contribute to this disorder. Since the onset of IBD is often during infancy, in the present study, the serum values of a large panel of cytokines and chemokines in pediatric patients (<18 years; n=26) were compared with age-matched controls (n=37). While elevations in the serum level of several proinflammatory and immune regulating cytokines were confirmed, such as interleukin (IL)-1β, IL-5, IL-7, interferon (IFN)-γ-inducible protein-10, IL-16, cutaneous T-cell-attracting chemokine, leukemia inhibitory factor, monokine induced by γ-IFN, IFN-α2 and IFN-γ, notably decreased levels of IL-2, IL-17 and macrophage inhibitory protein-1β were also observed. Therefore, while a number of proinflammatory cytokines exhibit increased levels in IBD patients, pediatric IBD patients may also exhibit certain aspects of a reduced immunological response.

  19. Monitoring Chemokine Receptor Trafficking by Confocal Immunofluorescence Microscopy

    PubMed Central

    Marchese, Adriano

    2016-01-01

    Here, we describe a protocol to detect chemokine receptor CXCR4 by confocal immunofluorescence microscopy in HeLa cells treated with its chemokine ligand CXCL12. Typically, ligand-activated chemokine receptors undergo a multistep process of desensitization and/or internalization from the plasma membrane in order to terminate signaling. Once internalized to endosomes, chemokine receptors readily enter the recycling pathway and return to the cell surface, giving rise to resensitization of signaling. The chemokine receptor CXCR4, when activated by CXCL12 is also internalized to endosomes, but in contrast to many chemokine receptors it is mainly sorted to the degradative pathway, contributing to a loss in the cellular complement of CXCR4 and long-term downregulation of signaling. The trafficking of CXCR4 from early endosomes to lysosomes can be easily detected by confocal immunofluorescence microscopy by immunostaining fixed cells for the receptor and with markers of these vesicular compartments. This approach is advantageous because it can be used to identify factors that regulate the trafficking of CXCR4 from early endosomes to lysosomes. The protocol described here focuses on CXCR4, but it can be easily adapted to other chemokine receptors. PMID:26921951

  20. MicroRNA-126 inhibits colon cancer cell proliferation and invasion by targeting the chemokine (C-X-C motif) receptor 4 and Ras homolog gene family, member A, signaling pathway

    PubMed Central

    Yuan, Wei; Guo, Ye-Qing; Li, Xia-Yu; Deng, Min-Zi; Shen, Zhao-Hua; Bo, Chi-Bin; Dai, Ya-Fei; Huang, Ming-Yu; Yang, Zhen-Yu; Quan, Yong-Sheng; Tian, Li; Wang, Xiaoyan

    2016-01-01

    MicroRNA-126 (miR-126) suppresses the migration, proliferation and invasion of colon cancer cells. However, the underlying mechanisms of miR-126 in colon cancer have not been fully elucidated. In this study, in vivo experiments revealed that miR-126 inhibits colon cancer growth and metastasis. Furthermore, miR-126 was down-regulated in human colon cancer tissue, and its expression was inversely correlated with TNM stage and metastasis of patients. Low level of miR-126 identified patients with poor prognosis. And we found that miR-126 expression was negatively correlated with the expression levels of chemokine (C-X-C motif) receptor 4 (CXCR4) and components of signaling pathway of Ras homolog gene family, member A (RhoA) in vitro and in vivo. Moreover, we verified that miR-126 negatively regulated CXCR4 and RhoA signaling in vitro. In addition, either in miR-126-overexpressing or in miR- 126-silenced colon cancer cells, the restoration of CXCR4 could significantly reverse the proliferation and invasion, as well as abolish the effects of miR-126 on RhoA signaling pathway. Collectively, these results demonstrated that miR-126 acts as a tumor suppressor by inactivating RhoA signaling via CXCR4 in colon cancer. And miR-126 may serve as a prognostic marker for monitoring and treating colon cancer. PMID:27517626

  1. Chemokine Involvement in Fetal and Adult Wound Healing

    PubMed Central

    Balaji, Swathi; Watson, Carey L.; Ranjan, Rajeev; King, Alice; Bollyky, Paul L.; Keswani, Sundeep G.

    2015-01-01

    Significance: Fetal wounds heal with a regenerative phenotype that is indistinguishable from surrounding skin with restored skin integrity. Compared to this benchmark, all postnatal wound healing is impaired and characterized by scar formation. The biologic basis of the fetal regenerative phenotype can serve as a roadmap to recapitulating regenerative repair in adult wounds. Reduced leukocyte infiltration, likely mediated, in part, through changes in the chemokine milieu, is a fundamental feature of fetal wound healing. Recent Advances: The contributions of chemokines to wound healing are a topic of active investigation. Recent discoveries have opened the possibility of targeting chemokines therapeutically to treat disease processes and improve healing capability, including the possibility of achieving a scarless phenotype in postnatal wounds. Critical Issues: Successful wound healing is a complex process, in which there is a significant interplay between multiple cell types, signaling molecules, growth factors, and extracellular matrix. Chemokines play a crucial role in this interplay and have been shown to have different effects in various stages of the healing process. Understanding how these chemokines are locally produced and regulated during wound healing and how the chemokine milieu differs in fetal versus postnatal wounds may help us identify ways in which we can target chemokine pathways. Future Directions: Further studies on the role of chemokines and their role in the healing process will greatly advance the potential for using these molecules as therapeutic targets. PMID:26543680

  2. Transendothelial migration of lymphocytes mediated by intraendothelial vesicle stores rather than by extracellular chemokine depots.

    PubMed

    Shulman, Ziv; Cohen, Shmuel J; Roediger, Ben; Kalchenko, Vyacheslav; Jain, Rohit; Grabovsky, Valentin; Klein, Eugenia; Shinder, Vera; Stoler-Barak, Liat; Feigelson, Sara W; Meshel, Tsipi; Nurmi, Susanna M; Goldstein, Itamar; Hartley, Olivier; Gahmberg, Carl G; Etzioni, Amos; Weninger, Wolfgang; Ben-Baruch, Adit; Alon, Ronen

    2011-12-04

    Chemokines presented by the endothelium are critical for integrin-dependent adhesion and transendothelial migration of naive and memory lymphocytes. Here we found that effector lymphocytes of the type 1 helper T cell (T(H)1 cell) and type 1 cytotoxic T cell (T(C)1 cell) subtypes expressed adhesive integrins that bypassed chemokine signals and established firm arrests on variably inflamed endothelial barriers. Nevertheless, the transendothelial migration of these lymphocytes strictly depended on signals from guanine nucleotide-binding proteins of the G(i) type and was promoted by multiple endothelium-derived inflammatory chemokines, even without outer endothelial surface exposure. Instead, transendothelial migration-promoting endothelial chemokines were stored in vesicles docked on actin fibers beneath the plasma membranes and were locally released within tight lymphocyte-endothelial synapses. Thus, effector T lymphocytes can cross inflamed barriers through contact-guided consumption of intraendothelial chemokines without surface-deposited chemokines or extraendothelial chemokine gradients.

  3. The role of chemokines in term and premature rupture of the fetal membranes: a review.

    PubMed

    Gomez-Lopez, Nardhy; Laresgoiti-Servitje, Estibalitz; Olson, David M; Estrada-Gutiérrez, Guadalupe; Vadillo-Ortega, Felipe

    2010-05-01

    Several studies indicate that at the choriodecidual interface, where maternal and fetal tissues make contact, a network of signals is established during labor that includes infiltration of leukocytes and secretion of pro-inflammatory cytokines. In this review, we provide an overview of the inflammatory milieu present in the choriodecidua during membrane rupture, describe the recruitment and homing of leukocytes to the reproductive tissues, and detail specific actions of the key chemokines released by the choriodecidual cells. These data lend further support to the hypothesis that labor is an inflammatory response, wherein the infiltrated leukocytes in the choriodecidua interface could be contributing to the creation of a microenvironment leading to collagenolysis, which would promote the rupture of these tissues during labor. In addition to the available information describing biological actions of chemokines during various pathological conditions such as infection, preterm labor and preterm rupture of membranes suggest that these compounds play important roles in other gestational events such as cervical dilation and myometrial contractions. Even though we do not know the totality of biochemical signals that integrate the molecular dialogue between leukocytes and the various gestational tissues, it is becoming increasingly evident that this microenvironment is characterized, at least in part, by the differential expression and secretion of chemokines that induce selective trafficking of leukocyte subsets to the fetal membranes. Therefore, chemokines should be considered as important regulatory molecules with the ability to initiate the events that characterize normal and pathological labor.

  4. Stress increases aversive prediction error signal in the ventral striatum.

    PubMed

    Robinson, Oliver J; Overstreet, Cassie; Charney, Danielle R; Vytal, Katherine; Grillon, Christian

    2013-03-05

    From job interviews to the heat of battle, it is evident that people think and learn differently when stressed. In fact, learning under stress may have long-term consequences; stress facilitates aversive conditioning and associations learned during extreme stress may result in debilitating emotional responses in posttraumatic stress disorder. The mechanisms underpinning such stress-related associations, however, are unknown. Computational neuroscience has successfully characterized several mechanisms critical for associative learning under normative conditions. One such mechanism, the detection of a mismatch between expected and observed outcomes within the ventral striatum (i.e., "prediction errors"), is thought to be a critical precursor to the formation of new stimulus-outcome associations. An untested possibility, therefore, is that stress may affect learning via modulation of this mechanism. Here we combine a translational model of stress with a cognitive neuroimaging paradigm to demonstrate that stress significantly increases ventral striatum aversive (but not appetitive) prediction error signal. This provides a unique account of the propensity to form threat-related associations under stress with direct implications for our understanding of both normal stress and stress-related disorders.

  5. Dystrophic muscle improvement in zebrafish via increased heme oxygenase signaling

    PubMed Central

    Kawahara, Genri; Gasperini, Molly J.; Myers, Jennifer A.; Widrick, Jeffrey J.; Eran, Alal; Serafini, Peter R.; Alexander, Matthew S.; Pletcher, Mathew T.; Morris, Carl A.; Kunkel, Louis M.

    2014-01-01

    Duchenne muscular dystrophy (DMD) is caused by a lack of the dystrophin protein and has no effective treatment at present. Zebrafish provide a powerful in vivo tool for high-throughput therapeutic drug screening for the improvement of muscle phenotypes caused by dystrophin deficiency. Using the dystrophin-deficient zebrafish, sapje, we have screened a total of 2640 compounds with known modes of action from three drug libraries to identify modulators of the disease progression. Six compounds that target heme oxygenase signaling were found to rescue the abnormal muscle phenotype in sapje and sapje-like, while upregulating the inducible heme oxygenase 1 (Hmox1) at the protein level. Direct Hmox1 overexpression by injection of zebrafish Hmox1 mRNA into fertilized eggs was found to be sufficient for a dystrophin-independent restoration of normal muscle via an upregulation of cGMP levels. In addition, treatment of mdx5cv mice with the PDE5 inhibitor, sildenafil, which was one of the six drugs impacting the Hmox1 pathway in zebrafish, significantly increased the expression of Hmox1 protein, thus making Hmox1 a novel target for the improvement of dystrophic symptoms. These results demonstrate the translational relevance of our zebrafish model to mammalian models and support the use of zebrafish to screen for new drugs to treat human DMD. The discovery of a small molecule and a specific therapeutic pathway that might mitigate DMD disease progression could lead to significant clinical implications. PMID:24234649

  6. Increased Brain Signal Variability Accompanies Lower Behavioral Variability in Development

    PubMed Central

    McIntosh, Anthony Randal; Kovacevic, Natasa; Itier, Roxane J.

    2008-01-01

    As the brain matures, its responses become optimized. Behavioral measures show this through improved accuracy and decreased trial-to-trial variability. The question remains whether the supporting brain dynamics show a similar decrease in variability. We examined the relation between variability in single trial evoked electrical activity of the brain (measured with EEG) and performance of a face memory task in children (8–15 y) and young adults (20–33 y). Behaviorally, children showed slower, more variable response times (RT), and less accurate recognition than adults. However, brain signal variability increased with age, and showed strong negative correlations with intrasubject RT variability and positive correlations with accuracy. Thus, maturation appears to lead to a brain with greater functional variability, which is indicative of enhanced neural complexity. This variability may reflect a broader repertoire of metastable brain states and more fluid transitions among them that enable optimum responses. Our results suggest that the moment-to-moment variability in brain activity may be a critical index of the cognitive capacity of the brain. PMID:18604265

  7. Influenza A Viruses Replicate Productively in Mouse Mastocytoma Cells (P815) and Trigger Pro-inflammatory Cytokine and Chemokine Production through TLR3 Signaling Pathway

    PubMed Central

    Meng, Di; Huo, Caiyun; Wang, Ming; Xiao, Jin; Liu, Bo; Wei, Tangting; Dong, Hong; Zhang, Guozhong; Hu, Yanxin; Sun, Lunquan

    2017-01-01

    The influenza A viruses (IAVs) cause acute respiratory infection in both humans and animals. As a member of the initial lines of host defense system, the role of mast cells during IAV infection has been poorly understood. Here, we characterized for the first time that both avian-like (α-2, 3-linked) and human-like (α-2, 6- linked) sialic acid (SA) receptors were expressed by the mouse mastocytoma cell line (P815). The P815 cells did support the productive replication of H1N1 (A/WSN/33), H5N1 (A/chicken/ Henan/1/04) and H7N2 (A/chicken/Hebei/2/02) in vitro while the in vivo infection of H5N1 in mast cells was confirmed by the specific staining of nasal mucosa and lung tissue from mice. All the three viruses triggered the infected P815 cells to produce pro-inflammatory cytokines and chemokines including IL-6, IFN-γ, TNF-α, CCL-2, CCL-5, and IP-10, but not the antiviral type I interferon. It was further confirmed that TLR3 pathway was involved in P815 cell response to IAV-infection. Our findings highlight the remarkable tropism and infectivity of IAV to P815 cells, indicating that mast cells may be unneglectable player in the development of IAV infection. PMID:28127293

  8. Mechanisms of Regulation of the Chemokine-Receptor Network

    PubMed Central

    Stone, Martin J.; Hayward, Jenni A.; Huang, Cheng; E. Huma, Zil; Sanchez, Julie

    2017-01-01

    The interactions of chemokines with their G protein-coupled receptors promote the migration of leukocytes during normal immune function and as a key aspect of the inflammatory response to tissue injury or infection. This review summarizes the major cellular and biochemical mechanisms by which the interactions of chemokines with chemokine receptors are regulated, including: selective and competitive binding interactions; genetic polymorphisms; mRNA splice variation; variation of expression, degradation and localization; down-regulation by atypical (decoy) receptors; interactions with cell-surface glycosaminoglycans; post-translational modifications; oligomerization; alternative signaling responses; and binding to natural or pharmacological inhibitors. PMID:28178200

  9. Neutralizing nanobodies targeting diverse chemokines effectively inhibit chemokine function.

    PubMed

    Blanchetot, Christophe; Verzijl, Dennis; Mujić-Delić, Azra; Bosch, Leontien; Rem, Louise; Leurs, Rob; Verrips, C Theo; Saunders, Michael; de Haard, Hans; Smit, Martine J

    2013-08-30

    Chemokine receptors and their ligands play a prominent role in immune regulation but many have also been implicated in inflammatory diseases such as multiple sclerosis, rheumatoid arthritis, allograft rejection after transplantation, and also in cancer metastasis. Most approaches to therapeutically target the chemokine system involve targeting of chemokine receptors with low molecular weight antagonists. Here we describe the selection and characterization of an unprecedented large and diverse panel of neutralizing Nanobodies (single domain camelid antibodies fragment) directed against several chemokines. We show that the Nanobodies directed against CCL2 (MCP-1), CCL5 (RANTES), CXCL11 (I-TAC), and CXCL12 (SDF-1α) bind the chemokines with high affinity (at nanomolar concentration), thereby blocking receptor binding, inhibiting chemokine-induced receptor activation as well as chemotaxis. Together, we show that neutralizing Nanobodies can be selected efficiently for effective and specific therapeutic treatment against a wide range of immune and inflammatory diseases.

  10. Novel antiviral activity of chemokines

    SciTech Connect

    Nakayama, Takashi; Shirane, Jumi; Hieshima, Kunio; Shibano, Michiko; Watanabe, Masayasu; Jin, Zhe; Nagakubo, Daisuke; Saito, Takuya; Shimomura, Yoshikazu; Yoshie, Osamu . E-mail: o.yoshie@med.kindai.ac.jp

    2006-07-05

    Antimicrobial peptides are a diverse family of small, mostly cationic polypeptides that kill bacteria, fungi and even some enveloped viruses, while chemokines are a group of mostly cationic small proteins that induce directed migration of leukocytes through interactions with a group of seven transmembrane G protein-coupled receptors. Recent studies have shown that antimicrobial peptides and chemokines have substantially overlapping functions. Thus, while some antimicrobial peptides are chemotactic for leukocytes, some chemokines can kill a wide range of bacteria and fungi. Here, we examined a possible direct antiviral activity of chemokines against an enveloped virus HSV-1. Among 22 human chemokines examined, chemokines such as MIP-1{alpha}/CCL3, MIP-1{beta}/CCL4 and RANTES/CCL5 showed a significant direct antiviral activity against HSV-1. It is intriguing that these chemokines are mostly known to be highly expressed by effector CD8{sup +} T cells. The chemokines with a significant anti-HSV-1 activity commonly bound to HSV-1 virions via envelope glycoprotein gB. Electron microscopy revealed that the chemokines with a significant anti-HSV-1 activity were commonly capable of generating pores in the envelope of HSV-1. Thus, some chemokines have a significant direct antiviral activity against HSV-1 in vitro and may have a potential role in host defense against HSV-1 as a direct antiviral agent.

  11. Environmental Factors Impacting Bone-Relevant Chemokines

    PubMed Central

    Smith, Justin T.; Schneider, Andrew D.; Katchko, Karina M.; Yun, Chawon; Hsu, Erin L.

    2017-01-01

    Chemokines play an important role in normal bone physiology and the pathophysiology of many bone diseases. The recent increased focus on the individual roles of this class of proteins in the context of bone has shown that members of the two major chemokine subfamilies—CC and CXC—support or promote the formation of new bone and the remodeling of existing bone in response to a myriad of stimuli. These chemotactic molecules are crucial in orchestrating appropriate cellular homing, osteoblastogenesis, and osteoclastogenesis during normal bone repair. Bone healing is a complex cascade of carefully regulated processes, including inflammation, progenitor cell recruitment, differentiation, and remodeling. The extensive role of chemokines in these processes and the known links between environmental contaminants and chemokine expression/activity leaves ample opportunity for disruption of bone healing by environmental factors. However, despite increased clinical awareness, the potential impact of many of these environmental factors on bone-related chemokines is still ill defined. A great deal of focus has been placed on environmental exposure to various endocrine disruptors (bisphenol A, phthalate esters, etc.), volatile organic compounds, dioxins, and heavy metals, though mainly in other tissues. Awareness of the impact of other less well-studied bone toxicants, such as fluoride, mold and fungal toxins, asbestos, and chlorine, is also reviewed. In many cases, the literature on these toxins in osteogenic models is lacking. However, research focused on their effects in other tissues and cell lines provides clues for where future resources could be best utilized. This review aims to serve as a current and exhaustive resource detailing the known links between several classes of high-interest environmental pollutants and their interaction with the chemokines relevant to bone healing. PMID:28261155

  12. Modulation of Chemokine Receptor Function by Cholesterol: New Prospects for Pharmacological Intervention.

    PubMed

    Legler, Daniel F; Matti, Christoph; Laufer, Julia M; Jakobs, Barbara D; Purvanov, Vladimir; Uetz-von Allmen, Edith; Thelen, Marcus

    2017-04-01

    Chemokine receptors are seven transmembrane-domain receptors belonging to class A of G-protein-coupled receptors (GPCRs). The receptors together with their chemokine ligands constitute the chemokine system, which is essential for directing cell migration and plays a crucial role in a variety of physiologic and pathologic processes. Given the importance of orchestrating cell migration, it is vital that chemokine receptor signaling is tightly regulated to ensure appropriate responses. Recent studies highlight a key role for cholesterol in modulating chemokine receptor activities. The steroid influences the spatial organization of GPCRs within the membrane bilayer, and consequently can tune chemokine receptor signaling. The effects of cholesterol on the organization and function of chemokine receptors and GPCRs in general include direct and indirect effects (Fig. 1). Here, we review how cholesterol and some key metabolites modulate functions of the chemokine system in multiple ways. We emphasize the role of cholesterol in chemokine receptor oligomerization, thereby promoting the formation of a signaling hub enabling integration of distinct signaling pathways at the receptor-membrane interface. Moreover, we discuss the role of cholesterol in stabilizing particular receptor conformations and its consequence for chemokine binding. Finally, we highlight how cholesterol accumulation, its deprivation, or cholesterol metabolites contribute to modulating cell orchestration during inflammation, induction of an adaptive immune response, as well as to dampening an anti-tumor immune response.

  13. Chemotaxis, chemokine receptors and human disease.

    PubMed

    Jin, Tian; Xu, Xuehua; Hereld, Dale

    2008-10-01

    Cell migration is involved in diverse physiological processes including embryogenesis, immunity, and diseases such as cancer and chronic inflammatory disease. The movement of many cell types is directed by extracellular gradients of diffusible chemicals. This phenomenon, referred to as "chemotaxis", was first described in 1888 by Leber who observed the movement of leukocytes toward sites of inflammation. We now know that a large family of small proteins, chemokines, serves as the extracellular signals and a family of G-protein-coupled receptors (GPCRs), chemokine receptors, detects gradients of chemokines and guides cell movement in vivo. Currently, we still know little about the molecular machineries that control chemokine gradient sensing and migration of immune cells. Fortunately, the molecular mechanisms that control these fundamental aspects of chemotaxis appear to be evolutionarily conserved, and studies in lower eukaryotic model systems have allowed us to form concepts, uncover molecular components, develop new techniques, and test models of chemotaxis. These studies have helped our current understanding of this complicated cell behavior. In this review, we wish to mention landmark discoveries in the chemotaxis research field that shaped our current understanding of this fundamental cell behavior and lay out key questions that remain to be addressed in the future.

  14. Radiation results in IL-8 mediated intercellular signaling that increases adhesion between monocytic cells and aortic endothelium

    NASA Astrophysics Data System (ADS)

    Kucik, Dennis; Babitz, Stephen; Dunaway, Chad; Steele, Chad

    cells (HAECs) in vitro under conditions that mimic the shear stress in the bloodstream. For both heavy ions and x-rays, these adhesiveness changes are independent of adhesion molecule expression levels, but are chemokine dependent. Here we identify the specific endothelial chemokine responsible for this radiation-induced adhesiveness. X-irradiation increased IL-8 secretion almost 5-fold, while having little or no effect on expression of 15 other chemokines. Adhesiveness was then assayed under physiological shear stress using a flow chamber adhesion assay. Radiation significantly increased endothelial adhesiveness. The radiation-induced adhesiveness was specifically blocked by anti-IL-8 antibody, with no effect on baseline, radiation-independent adhesion. Addition of recombinant human IL-8 to un-irradiated HAECs was sufficient to increase adhesion to the same level as x-rays. Therefore, radiation-induced IL-8 signaling is both necessary and sufficient for radiation effects on aortic endothelial adhesiveness. This IL-8 induced adhesiveness may explain, at least in part, the mechanism by which radiation accelerates development of atherosclerosis. A better understanding of this mechanism can provide the basis for future countermeasure development.

  15. Chemokines in cancer related inflammation

    SciTech Connect

    Allavena, Paola; Germano, Giovanni; Marchesi, Federica; Mantovani, Alberto

    2011-03-10

    Chemokines are key players of the cancer-related inflammation. Chemokine ligands and receptors are downstream of genetic events that cause neoplastic transformation and are abundantly expressed in chronic inflammatory conditions which predispose to cancer. Components of the chemokine system affect multiple pathways of tumor progression including: leukocyte recruitment, neo-angiogenesis, tumor cell proliferation and survival, invasion and metastasis. Evidence in pre-clinical and clinical settings suggests that the chemokine system represents a valuable target for the development of innovative therapeutic strategies.

  16. The fine balance of chemokines during disease: trafficking, inflammation, and homeostasis.

    PubMed

    Cardona, Sandra M; Garcia, Jenny A; Cardona, Astrid E

    2013-01-01

    The action of chemokines (or "chemotactic cytokines") is recognized as an integral part of inflammatory and regulatory processes. Leukocyte mobilization during physiological conditions, trafficking of various cell types during pathological conditions, cell activation, and angiogenesis are among the target functions exerted by chemokines upon signaling via their specific receptors. Current research is focused in analyzing changes in chemokine/chemokine receptor patterns during various diseases with the aim to modulate pathological trafficking of cells, or to attract particular cell types to specific tissues. This review focuses on defining the role(s) of certain chemokine ligands and receptors in inflammatory neurological conditions such as multiple sclerosis. In addition, the role(s) of chemokines in neurodegenerative conditions such as Alzheimer's disease and Parkinson's disease is also described, as well as the contribution of chemokines to the pathogenesis of cancer, diabetes, and cardiovascular disease.

  17. Roflumilast n-oxide associated with PGE2 prevents the neutrophil elastase-induced production of chemokines by epithelial cells.

    PubMed

    Victoni, Tatiana; Gicquel, Thomas; Bodin, Aude; Daude, Marion; Tenor, Hermann; Valença, Samuel; Devillier, Philippe; Porto, Luis Cristovão; Lagente, Vincent; Boichot, Elisabeth

    2016-01-01

    Neutrophil chemotaxis is involved in the lung inflammatory process in conditions such as chronic obstructive pulmonary disease (COPD). Neutrophil elastase (NE), one of the main proteases produced by neutrophils, has an important role in the inflammatory process via the release of chemokines from airway epithelial cells. It was recently shown that roflumilast N-oxide has therapeutic potential in COPD. The aim of the present study was to investigate roflumilast N-oxide's effect on NE-induced chemokine production and signaling pathways in A549 epithelial cells. A549 cells were incubated with NE for 30min, washed with PBS and then cultured for 2h (for measurement of mRNA expression) and 24h (for chemokine release) or for 5 to 30min (for protein phosphorylation assays). Prior to the addition of NE, cells were also pre-incubated with prostaglandin E2 (PGE2), alone and in combination with roflumilast N-oxide. Addition of NE was associated with elevated chemokine production by A549 cells and induction of the p38α pathway. In contrast when combined with PGE2, the roflumilast N-oxide had an additive effect on the inhibition of NE-induced chemokine release and p38α and other kinases activation. In conclusion, we demonstrated that NE is able to increase the release of chemokines from epithelial cells via the activation of p38α MAP-kinase and that roflumilast N-oxide when combined with PGE2 lowers NE-induced kinase activation and chemokine production.

  18. CC chemokines induce neutrophils to chemotaxis, degranulation, and alpha-defensin release.

    PubMed

    Jan, Ming-Shiou; Huang, Yi-Hsien; Shieh, Biehuoy; Teng, Ru-Hsiu; Yan, Yao-Pei; Lee, Yuan-Ti; Liao, Ko-Kaung; Li, Ching

    2006-01-01

    We have previously shown that a Taiwanese cohort of HIV-uninfected individuals was associated with the significantly elevated levels of serum beta-chemokines, macrophage inflammatory protein (MIP-1)-alpha and MIP-beta, and RANTES. In the present study, we report that the members of this cohort have significantly greater numbers of lower buoyant-density neutrophils in their blood, which leads to further investigation of the effects of beta-chemokines on neutrophils. By electron and confocal microscopic techniques and FACScan, the results demonstrated that MIP-1alpha, MIP-beta, and/or RANTES readily activated the cells to release a large quantity of alpha-defensins in vitro through the degranulation process, which was the cause of low-buoyant-density neutrophil production. The purified neutrophils underwent chemotaxis and increased phagocytic capability when beta-chemokines were present. Only when using all 3 neutralizing antibodies for CCR1, CCR3, and CCR5 could the chemotaxis of neutrophils be inhibited completely, suggesting that these receptors are involved in transducing activating signals. Because neutrophils are the most abundant white blood cells that can be activated simultaneously to release alpha-defensins and because these proteins are antiviral, including anti-HIV, our results support the hypothesis that in addition to beta-chemokines, the innate immunity of the cohort plays a role in inhibiting the transmission of HIV.

  19. [Hypothalamic inflammation and energy balance deregulations: focus on chemokines.

    PubMed

    Le Thuc, Ophélia; Rovère, Carole

    2016-01-01

    The hypothalamus is a key brain region in the regulation of energy balance. It especially controls food intake and both energy storage and expenditure through integration of humoral, neural and nutrient-related signals and cues. Hypothalamic neurons and glial cells act jointly to orchestrate, both spatially and temporally, regulated metabolic functions of the hypothalamus. Thus, the existence of a causal link between hypothalamic inflammation and deregulations of feeding behavior, such as involuntary weight-loss or obesity, has been suggested. Among the inflammatory mediators that could induce deregulations of hypothalamic control of the energy balance, chemokines represent interesting candidates. Indeed, chemokines, primarily known for their chemoattractant role of immune cells to the inflamed site, have also been suggested capable of neuromodulation. Thus, chemokines could disrupt cellular activity together with synthesis and/or secretion of multiple neurotransmitters/mediators that are involved in the maintenance of energy balance. Here, we relate, on one hand, recent results showing the primary role of the central chemokinergic signaling CCL2/CCR2 for metabolic and behavioral adaptation to high-grade inflammation, especially loss of appetite and weight, through its activity on hypothalamic neurons producing the orexigenic peptide Melanin-Concentrating Hormone (MCH) and, on the other hand, results that suggest that chemokines could also deregulate hypothalamic neuropeptidergic circuits to induce an opposite phenotype and eventually participate in the onset/development of obesity. In more details, we will emphasize a study recently showing, in a model of high-grade acute inflammation of LPS injection in mice, that central CCL2/CCR2 signaling is of primary importance for several aspects explaining weight loss associated with inflammation: after LPS injection, animals lose weight, reduce their food intake, increase their fat oxidation (thus energy consumption from

  20. SMM-chemokines: a class of unnatural synthetic molecules as chemical probes of chemokine receptor biology and leads for therapeutic development.

    PubMed

    Kumar, Santosh; Choi, Won-Tak; Dong, Chang-Zhi; Madani, Navid; Tian, Shaomin; Liu, Dongxiang; Wang, Youli; Pesavento, James; Wang, Jun; Fan, Xuejun; Yuan, Jian; Fritzsche, Wayne R; An, Jing; Sodroski, Joseph G; Richman, Douglas D; Huang, Ziwei

    2006-01-01

    Chemokines and their receptors play important roles in numerous physiological and pathological processes. To develop natural chemokines into receptor probes and inhibitors of pathological processes, the lack of chemokine-receptor selectivity must be overcome. Here, we apply chemical synthesis and the concept of modular modifications to generate unnatural synthetically and modularly modified (SMM)-chemokines that have high receptor selectivity and affinity, and reduced toxicity. A proof of the concept was shown by transforming the nonselective viral macrophage inflammatory protein-II into new analogs with enhanced selectivity and potency for CXCR4 or CCR5, two principal coreceptors for human immunodeficiency virus (HIV)-1 entry. These new analogs provided insights into receptor binding and signaling mechanisms and acted as potent HIV-1 inhibitors. These results support the concept of SMM-chemokines for studying and controlling the function of other chemokine receptors.

  1. ACKR2: An Atypical Chemokine Receptor Regulating Lymphatic Biology

    PubMed Central

    Bonavita, Ornella; Mollica Poeta, Valeria; Setten, Elisa; Massara, Matteo; Bonecchi, Raffaella

    2017-01-01

    The lymphatic system plays an important role in the induction of the immune response by transporting antigens, inflammatory mediators, and leukocytes from peripheral tissues to draining lymph nodes. It is emerging that lymphatic endothelial cells (LECs) are playing an active role in this context via the expression of chemokines, inflammatory mediators promoting cell migration, and chemokine receptors. Particularly, LECs express atypical chemokine receptors (ACKRs), which are unable to promote conventional signaling and cell migration while they are involved in the regulation of chemokine availability. Here, we provide a summary of the data on the role of ACKR2 expressed by lymphatics, indicating an essential role for this ACKRs in the regulation of the inflammation and the immune response in different pathological conditions, including infection, allergy, and cancer. PMID:28123388

  2. Vascular Stem/Progenitor Cell Migration Induced by Smooth Muscle Cell‐Derived Chemokine (C‐C Motif) Ligand 2 and Chemokine (C‐X‐C motif) Ligand 1 Contributes to Neointima Formation

    PubMed Central

    Yu, Baoqi; Wong, Mei Mei; Potter, Claire M. F.; Simpson, Russell M. L.; Karamariti, Eirini; Zhang, Zhongyi; Zeng, Lingfang; Warren, Derek; Hu, Yanhua

    2016-01-01

    Abstract Recent studies have shown that Sca‐1+ (stem cell antigen‐1) stem/progenitor cells within blood vessel walls may contribute to neointima formation, but the mechanism behind their recruitment has not been explored. In this work Sca‐1+ progenitor cells were cultivated from mouse vein graft tissue and found to exhibit increased migration when cocultured with smooth muscle cells (SMCs) or when treated with SMC‐derived conditioned medium. This migration was associated with elevated levels of chemokines, CCL2 (chemokine (C‐C motif) ligand 2) and CXCL1 (chemokine (C‐X‐C motif) ligand 1), and their corresponding receptors on Sca‐1+ progenitors, CCR2 (chemokine (C‐C motif) receptor 2) and CXCR2 (chemokine (C‐X‐C motif) receptor 2), which were also upregulated following SMC conditioned medium treatment. Knockdown of either receptor in Sca‐1+ progenitors significantly inhibited cell migration. The GTPases Cdc42 and Rac1 were activated by both CCL2 and CXCL1 stimulation and p38 phosphorylation was increased. However, only Rac1 inhibition significantly reduced migration and p38 phosphorylation. After Sca‐1+ progenitors labeled with green fluorescent protein (GFP) were applied to the adventitial side of wire‐injured mouse femoral arteries, a large proportion of GFP‐Sca‐1+‐cells were observed in neointimal lesions, and a marked increase in neointimal lesion formation was seen 1 week post‐operation. Interestingly, Sca‐1+ progenitor migration from the adventitia to the neointima was abrogated and neointima formation diminished in a wire injury model using CCL2−/− mice. These findings suggest vascular stem/progenitor cell migration from the adventitia to the neointima can be induced by SMC release of chemokines which act via CCR2/Rac1/p38 and CXCR2/Rac1/p38 signaling pathways. Stem Cells 2016;34:2368–2380 PMID:27300479

  3. Dysfunctional nitric oxide signalling increases risk of myocardial infarction.

    PubMed

    Erdmann, Jeanette; Stark, Klaus; Esslinger, Ulrike B; Rumpf, Philipp Moritz; Koesling, Doris; de Wit, Cor; Kaiser, Frank J; Braunholz, Diana; Medack, Anja; Fischer, Marcus; Zimmermann, Martina E; Tennstedt, Stephanie; Graf, Elisabeth; Eck, Sebastian; Aherrahrou, Zouhair; Nahrstaedt, Janja; Willenborg, Christina; Bruse, Petra; Brænne, Ingrid; Nöthen, Markus M; Hofmann, Per; Braund, Peter S; Mergia, Evanthia; Reinhard, Wibke; Burgdorf, Christof; Schreiber, Stefan; Balmforth, Anthony J; Hall, Alistair S; Bertram, Lars; Steinhagen-Thiessen, Elisabeth; Li, Shu-Chen; März, Winfried; Reilly, Muredach; Kathiresan, Sekar; McPherson, Ruth; Walter, Ulrich; Ott, Jurg; Samani, Nilesh J; Strom, Tim M; Meitinger, Thomas; Hengstenberg, Christian; Schunkert, Heribert

    2013-12-19

    Myocardial infarction, a leading cause of death in the Western world, usually occurs when the fibrous cap overlying an atherosclerotic plaque in a coronary artery ruptures. The resulting exposure of blood to the atherosclerotic material then triggers thrombus formation, which occludes the artery. The importance of genetic predisposition to coronary artery disease and myocardial infarction is best documented by the predictive value of a positive family history. Next-generation sequencing in families with several affected individuals has revolutionized mutation identification. Here we report the segregation of two private, heterozygous mutations in two functionally related genes, GUCY1A3 (p.Leu163Phefs*24) and CCT7 (p.Ser525Leu), in an extended myocardial infarction family. GUCY1A3 encodes the α1 subunit of soluble guanylyl cyclase (α1-sGC), and CCT7 encodes CCTη, a member of the tailless complex polypeptide 1 ring complex, which, among other functions, stabilizes soluble guanylyl cyclase. After stimulation with nitric oxide, soluble guanylyl cyclase generates cGMP, which induces vasodilation and inhibits platelet activation. We demonstrate in vitro that mutations in both GUCY1A3 and CCT7 severely reduce α1-sGC as well as β1-sGC protein content, and impair soluble guanylyl cyclase activity. Moreover, platelets from digenic mutation carriers contained less soluble guanylyl cyclase protein and consequently displayed reduced nitric-oxide-induced cGMP formation. Mice deficient in α1-sGC protein displayed accelerated thrombus formation in the microcirculation after local trauma. Starting with a severely affected family, we have identified a link between impaired soluble-guanylyl-cyclase-dependent nitric oxide signalling and myocardial infarction risk, possibly through accelerated thrombus formation. Reversing this defect may provide a new therapeutic target for reducing the risk of myocardial infarction.

  4. Cobalt ions induce chemokine secretion in primary human osteoblasts.

    PubMed

    Queally, J M; Devitt, B M; Butler, J S; Malizia, A P; Murray, D; Doran, P P; O'Byrne, J M

    2009-07-01

    Chemokines are major regulators of the inflammatory response and have been shown to play an important role in periprosthetic osteolysis. Titanium particles have previously been shown to induce IL-8 and MCP-1 secretion in osteoblasts. These chemokines result in the chemotaxis and activation of neutrophils and macrophages, respectively. Despite a resurgence in the use of cobalt-chromium-molybdenum alloys in metal-on-metal arthroplasty, cobalt and chromium ion toxicity in the periprosthetic area has been insufficiently studied. In this study we investigate the in vitro effect of cobalt ions on primary human osteoblast activity. We demonstrate that cobalt ions rapidly induce the protein secretion of IL-8 and MCP-1 in primary human osteoblasts. This elevated chemokine secretion is preceded by an increase in the transcription of the corresponding chemokine gene. Using a Transwell migration chemotaxis assay we also demonstrate that the chemokines secreted are capable of inducing neutrophil and macrophage migration. Furthermore, cobalt ions significantly inhibit osteoblast function as demonstrated by reduced alkaline phosphatase activity and calcium deposition. In aggregate these data demonstrate that cobalt ions can activate transcription of the chemokine genes IL-8 and MCP-1 in primary human osteoblasts. Cobalt ions are not benign and may play an important role in the pathogenesis of osteolysis by suppressing osteoblast function and stimulating the production and secretion of chemokines that attract inflammatory and osteoclastic cells to the periprosthetic area.

  5. Molecular cloning, characterization and expression analysis of a CC chemokine gene from miiuy croaker (Miichthys miiuy).

    PubMed

    Cheng, Yuanzhi; Sun, Yuena; Shi, Ge; Wang, Rixin; Xu, Tianjun

    2012-12-01

    Chemokines are a family of structurally related chemotactic cytokines that regulate the migration of leukocytes, under both physiological and inflammatory conditions. A partial cDNA of CC chemokine gene designed as Mimi-CC3 was isolated from miiuy croaker (Miichthys miiuy) spleen cDNA library. Unknown 3' part of the cDNA was amplified by 3'-RACE. The complete cDNA of Mimi-CC3 contains an 89-nt 5'-UTR, a 303-nt open reading frame and a 441-nt 3'-UTR. Three exons and two introns were identified in Mimi-CC3. The deduced Mimi-CC3 protein sequences contain a 22 amino acids signal peptide and a 78 amino acids mature polypeptide, which possesses the typical arrangement of four cysteines as found in other known CC chemokines. It shares low amino acid sequence identities with most other fish and mammalian CC chemokines (less than 54.1 %), but shares very high identities with large yellow croaker CC chemokine (94.6 %). Phylogenetic analysis showed that Mimi-CC3 gene may have an orthologous relationship with mammalian/amphibian CCL25 gene. Tissue expression distributed analysis showed that Mimi-CC3 gene was constitutively expressed in all nine tissues examined, although at different levels. Upon stimulated with Vibrio anguillarum, the time-course analysis using a real-time PCR showed that Mimi-CC3 transcript in kidney and liver was obviously up-regulated and reached the peak levels, followed by a recovery. Mimi-CC3 expression in kidney was more strongly increased than in liver. However, down-regulation was observed in spleen. These results indicated that Mimi-CC3 plays important roles in miiuy croaker immune response as well as in homeostatic mechanisms.

  6. Single-Cell Analysis of Mast Cell Degranulation Induced by Airway Smooth Muscle-Secreted Chemokines

    PubMed Central

    Manning, Benjamin M.; Meyer, Audrey F.; Gruba, Sarah M.; Haynes, Christy L.

    2015-01-01

    Background Asthma is a chronic inflammatory disease characterized by narrowed airways, bronchial hyper-responsiveness, mucus hyper-secretion, and airway remodeling. Mast cell (MC) infiltration into airway smooth muscle (ASM) is a defining feature of asthma, and ASM regulates the inflammatory response by secreting chemokines, including CXCL10 and CCL5. Single cell analysis offers a unique approach to study specific cellular signaling interactions within large and complex signaling networks such as the inflammatory microenvironment in asthma. Methods Carbon fiber microelectrode amperometry was used to study the effects of ASM–secreted chemokines on mouse peritoneal MC degranulation. Results MC degranulation in response to CXCL10 and CCL5 was monitored at the single cell level. Relative to IgE-mediated degranulation, CXCL10- and CCL5-stimulated MCs released a decreased amount of serotonin per granule with fewer release events per cell. Decreased serotonin released per granule was correlated with increased spike half-width and rise-time values. Conclusions MCs are directly activated with ASM-associated chemokines. CXCL10 and CCL5 induce less robust MC degranulation compared to IgE- and A23187-stimulation. The kinetics of MC degranulation are signaling pathway-dependent, suggesting a biophysical mechanism of regulated degranulation that incorporates control over granule trafficking, transport, and docking machinery. General Significance The biophysical mechanisms, including variations in number of exocytotic release events, serotonin released per granule, and the membrane kinetics of exocytosis that underlie MC degranulation in response to CXCL10 and CCL5 were characterized at the single cell level. These findings clarify the function of ASM-derived chemokines as instigators of MC degranulation relative to classical mechanisms of MC stimulation. PMID:25986989

  7. The role of chemokines in hypertension and consequent target organ damage.

    PubMed

    Rudemiller, Nathan P; Crowley, Steven D

    2017-03-06

    Immune cells infiltrate the kidney, vasculature, and central nervous system during hypertension, consequently amplifying tissue damage and/or blood pressure elevation. Mononuclear cell motility depends partly on chemokines, which are small cytokines that guide cells through an increasing concentration gradient via ligation of their receptors. Tissue expression of several chemokines is elevated in clinical and experimental hypertension. Likewise, immune cells have enhanced chemokine receptor expression during hypertension, driving immune cell infiltration and inappropriate inflammation in cardiovascular control centers. T lymphocytes and monocytes/macrophages are pivotal mediators of hypertensive inflammation, and these cells migrate in response to several chemokines. As powerful drivers of diapedesis, the chemokines CCL2 and CCL5 have long been implicated in hypertension, but experimental data highlight divergent, context-specific effects of these chemokines on blood pressure and tissue injury. Several other chemokines, particularly those of the CXC family, contribute to blood pressure elevation and target organ damage. Given the significant interplay and chemotactic redundancy among chemokines during disease, future work must not only describe the actions of individual chemokines in hypertension, but also characterize how manipulating a single chemokine modulates the expression and/or function of other chemokines and their cognate receptors. This information will facilitate the design of precise chemotactic immunotherapies to limit cardiovascular and renal morbidity in hypertensive patients.

  8. Pregnancy in Obese Mice Protects Selectively against Visceral Adiposity and Is Associated with Increased Adipocyte Estrogen Signalling

    PubMed Central

    Pedroni, Silvia M. A.; Turban, Sophie; Kipari, Tiina; Dunbar, Donald R.; McInnes, Kerry; Saunders, Philippa T. K.; Morton, Nicholas M.; Norman, Jane E.

    2014-01-01

    Maternal obesity is linked with increased adverse pregnancy outcomes for both mother and child. The metabolic impact of excessive fat within the context of pregnancy is not fully understood. We used a mouse model of high fat (HF) feeding to induce maternal obesity to identify adipose tissue-mediated mechanisms driving metabolic dysfunction in pregnant and non-pregnant obese mice. As expected, chronic HF-feeding for 12 weeks preceding pregnancy increased peripheral (subcutaneous) and visceral (mesenteric) fat mass. However, unexpectedly at late gestation (E18.5) HF-fed mice exhibited a remarkable normalization of visceral but not peripheral adiposity, with a 53% reduction in non-pregnant visceral fat mass expressed as a proportion of body weight (P<0.001). In contrast, in control animals, pregnancy had no effect on visceral fat mass proportion. Obesity exaggerated glucose intolerance at mid-pregnancy (E14.5). However by E18.5, there were no differences, in glucose tolerance between obese and control mice. Transcriptomic analysis of visceral fat from HF-fed dams at E18.5 revealed reduced expression of genes involved in de novo lipogenesis (diacylglycerol O-acyltransferase 2 - Dgat2) and inflammation (chemokine C-C motif ligand 2 - Ccl2) and upregulation of estrogen receptor α (ERα) compared to HF non pregnant. Attenuation of adipose inflammation was functionally confirmed by a 45% reduction of CD11b+CD11c+ adipose tissue macrophages (expressed as a proportion of all stromal vascular fraction cells) in HF pregnant compared to HF non pregnant animals (P<0.001). An ERα selective agonist suppressed both de novo lipogenesis and expression of lipogenic genes in adipocytes in vitro. These data show that, in a HF model of maternal obesity, late gestation is associated with amelioration of visceral fat hypertrophy, inflammation and glucose intolerance, and suggest that these effects are mediated in part by elevated visceral adipocyte ERα signaling. PMID:24732937

  9. Cannabis Use: Signal of Increasing Risk of Serious Cardiovascular Disorders

    PubMed Central

    Jouanjus, Emilie; Lapeyre‐Mestre, Maryse; Micallef, Joelle

    2014-01-01

    Background Cannabis is known to be associated with neuropsychiatric problems, but less is known about complications affecting other specified body systems. We report and analyze 35 recent remarkable cardiovascular complications following cannabis use. Methods and Results In France, serious cases of abuse and dependence in response to the use of psychoactive substances must be reported to the national system of the French Addictovigilance Network. We identified all spontaneous reports of cardiovascular complications related to cannabis use collected by the French Addictovigilance Network from 2006 to 2010. We described the clinical characteristics of these cases and their evolution: 1.8% of all cannabis‐related reports (35/1979) were cardiovascular complications, with patients being mostly men (85.7%) and of an average age of 34.3 years. There were 22 cardiac complications (20 acute coronary syndromes), 10 peripheral complications (lower limb or juvenile arteriopathies and Buerger‐like diseases), and 3 cerebral complications (acute cerebral angiopathy, transient cortical blindness, and spasm of cerebral artery). In 9 cases, the event led to patient death. Conclusions Increased reporting of cardiovascular complications related to cannabis and their extreme seriousness (with a death rate of 25.6%) indicate cannabis as a possible risk factor for cardiovascular disease in young adults, in line with previous findings. Given that cannabis is perceived to be harmless by the general public and that legalization of its use is debated, data concerning its danger must be widely disseminated. Practitioners should be aware that cannabis may be a potential triggering factor for cardiovascular complications in young people. PMID:24760961

  10. GPR35/CXCR8 IS THE RECEPTOR OF THE MUCOSAL CHEMOKINE CXCL17

    PubMed Central

    Maravillas-Montero, José L.; Burkhardt, Amanda M.; Hevezi, Peter A.; Carnevale, Christina D.; Smit, Martine J.; Zlotnik, Albert

    2015-01-01

    Chemokines are chemotactic cytokines that direct the traffic of leukocytes and other cells in the body. Chemokines bind to G protein-coupled receptors (GPCRs) expressed on target cells to initiate signaling cascades and induce chemotaxis. Although the cognate receptors of most chemokines have been identified, the receptor for the mucosal chemokine CXCL17 is still undefined. Here we show that GPR35 is the receptor of CXCL17. GPR35 is expressed in mucosal tissues, in CXCL17-responsive monocytes, and in the THP-1 monocytoid cell line. Transfection of GPR35 into Ba/F3 cells rendered them responsive to CXCL17 as measured by calcium mobilization assays. Furthermore, GPR35 expression is downregulated in the lungs of Cxcl17-/- mice, which exhibit defects in macrophage recruitment to the lungs. We conclude that GPR35 is a novel chemokine receptor, and suggest that it should be named chemokine (C-X-C motif) receptor 8 (CXCR8). PMID:25411203

  11. Truncation of CXCL12 by CD26 reduces its CXC chemokine receptor 4- and atypical chemokine receptor 3-dependent activity on endothelial cells and lymphocytes.

    PubMed

    Janssens, Rik; Mortier, Anneleen; Boff, Daiane; Ruytinx, Pieter; Gouwy, Mieke; Vantilt, Bo; Larsen, Olav; Daugvilaite, Viktorija; Rosenkilde, Mette M; Parmentier, Marc; Noppen, Sam; Liekens, Sandra; Van Damme, Jo; Struyf, Sofie; Teixeira, Mauro M; Amaral, Flávio A; Proost, Paul

    2017-05-15

    The chemokine CXCL12 or stromal cell-derived factor 1/SDF-1 attracts hematopoietic progenitor cells and mature leukocytes through the G protein-coupled CXC chemokine receptor 4 (CXCR4). In addition, it interacts with atypical chemokine receptor 3 (ACKR3 or CXCR7) and glycosaminoglycans. CXCL12 activity is regulated through posttranslational cleavage by CD26/dipeptidyl peptidase 4 that removes two NH2-terminal amino acids. CD26-truncated CXCL12 does not induce calcium signaling or chemotaxis of mononuclear cells. CXCL12(3-68) was chemically synthesized de novo for detailed biological characterization. Compared to unmodified CXCL12, CXCL12(3-68) was no longer able to signal through CXCR4 via inositol trisphosphate (IP3), Akt or extracellular signal-regulated kinases 1 and 2 (ERK1/2). Interestingly, the recruitment of β-arrestin 2 to the cell membrane via CXCR4 by CXCL12(3-68) was abolished, whereas a weakened but significant β-arrestin recruitment remained via ACKR3. CXCL12-induced endothelial cell migration and signal transduction was completely abrogated by CD26. Intact CXCL12 hardly induced lymphocyte migration upon intra-articular injection in mice. In contrast, oral treatment of mice with the CD26 inhibitor sitagliptin reduced CD26 activity and CXCL12 cleavage in blood plasma. The potential of CXCL12 to induce intra-articular lymphocyte infiltration was significantly increased in sitagliptin-treated mice and CXCL12(3-68) failed to induce migration under both CD26-inhibiting and non-inhibiting conditions. In conclusion, CD26-cleavage skews CXCL12 towards β-arrestin dependent recruitment through ACKR3 and destroys the CXCR4-mediated lymphocyte chemoattractant properties of CXCL12 in vivo. Hence, pharmacological CD26-blockade in tissues may enhance CXCL12-induced inflammation.

  12. Angiogenic CXC chemokine expression during differentiation of human mesenchymal stem cells towards the osteoblastic lineage.

    PubMed

    Bischoff, D S; Zhu, J H; Makhijani, N S; Kumar, A; Yamaguchi, D T

    2008-02-15

    The potential role of ELR(+) CXC chemokines in early events in bone repair was studied using human mesenchymal stem cells (hMSCs). Inflammation, which occurs in the initial phase of tissue healing in general, is critical to bone repair. Release of cytokines from infiltrating immune cells and injured bone can lead to recruitment of MSCs to the region of repair. CXC chemokines bearing the Glu-Leu-Arg (ELR) motif are also released by inflammatory cells and serve as angiogenic factors stimulating chemotaxis and proliferation of endothelial cells. hMSCs, induced to differentiate with osteogenic medium (OGM) containing ascorbate, beta-glycerophosphate (beta-GP), and dexamethasone (DEX), showed an increase in mRNA and protein secretion of the ELR(+) CXC chemokines CXCL8 and CXCL1. CXCL8 mRNA half-life studies reveal an increase in mRNA stability upon OGM stimulation. Increased expression and secretion is a result of DEX in OGM and is dose-dependent. Inhibition of the glucocorticoid receptor with mifepristone only partially inhibits DEX-stimulated CXCL8 expression indicating both glucocorticoid receptor dependent and independent pathways. Treatment with signal transduction inhibitors demonstrate that this expression is due to activation of the ERK and p38 mitogen-activated protein kinase (MAPK) pathways and is mediated through the G(alphai)-coupled receptors. Angiogenesis assays demonstrate that OGM-stimulated conditioned media containing secreted CXCL8 and CXCL1 can induce angiogenesis of human microvascular endothelial cells in an in vitro Matrigel assay.

  13. Structural basis of ligand interaction with atypical chemokine receptor 3

    NASA Astrophysics Data System (ADS)

    Gustavsson, Martin; Wang, Liwen; van Gils, Noortje; Stephens, Bryan S.; Zhang, Penglie; Schall, Thomas J.; Yang, Sichun; Abagyan, Ruben; Chance, Mark R.; Kufareva, Irina; Handel, Tracy M.

    2017-01-01

    Chemokines drive cell migration through their interactions with seven-transmembrane (7TM) chemokine receptors on cell surfaces. The atypical chemokine receptor 3 (ACKR3) binds chemokines CXCL11 and CXCL12 and signals exclusively through β-arrestin-mediated pathways, without activating canonical G-protein signalling. This receptor is upregulated in numerous cancers making it a potential drug target. Here we collected over 100 distinct structural probes from radiolytic footprinting, disulfide trapping, and mutagenesis to map the structures of ACKR3:CXCL12 and ACKR3:small-molecule complexes, including dynamic regions that proved unresolvable by X-ray crystallography in homologous receptors. The data are integrated with molecular modelling to produce complete and cohesive experimentally driven models that confirm and expand on the existing knowledge of the architecture of receptor:chemokine and receptor:small-molecule complexes. Additionally, we detected and characterized ligand-induced conformational changes in the transmembrane and intracellular regions of ACKR3 that elucidate fundamental structural elements of agonism in this atypical receptor.

  14. Structural basis of ligand interaction with atypical chemokine receptor 3

    PubMed Central

    Gustavsson, Martin; Wang, Liwen; van Gils, Noortje; Stephens, Bryan S.; Zhang, Penglie; Schall, Thomas J.; Yang, Sichun; Abagyan, Ruben; Chance, Mark R.; Kufareva, Irina; Handel, Tracy M.

    2017-01-01

    Chemokines drive cell migration through their interactions with seven-transmembrane (7TM) chemokine receptors on cell surfaces. The atypical chemokine receptor 3 (ACKR3) binds chemokines CXCL11 and CXCL12 and signals exclusively through β-arrestin-mediated pathways, without activating canonical G-protein signalling. This receptor is upregulated in numerous cancers making it a potential drug target. Here we collected over 100 distinct structural probes from radiolytic footprinting, disulfide trapping, and mutagenesis to map the structures of ACKR3:CXCL12 and ACKR3:small-molecule complexes, including dynamic regions that proved unresolvable by X-ray crystallography in homologous receptors. The data are integrated with molecular modelling to produce complete and cohesive experimentally driven models that confirm and expand on the existing knowledge of the architecture of receptor:chemokine and receptor:small-molecule complexes. Additionally, we detected and characterized ligand-induced conformational changes in the transmembrane and intracellular regions of ACKR3 that elucidate fundamental structural elements of agonism in this atypical receptor. PMID:28098154

  15. Chemokine receptor CXCR4: role in gastrointestinal cancer.

    PubMed

    Lombardi, Lucia; Tavano, Francesca; Morelli, Franco; Latiano, Tiziana Pia; Di Sebastiano, Pierluigi; Maiello, Evaristo

    2013-12-01

    Chemokines (CK)s, small proinflammatory chemoattractant cytokines that bind to specific G-protein coupled seven-span transmembrane receptors, are major regulators of cell trafficking and adhesion. The CXCL12 [stromal cell-derived factor-1 (SDF-1)] binds primarily to CXC receptor 4 (CXCR4; CD184). The binding of CXCL12 to CXCR4 induces intracellular signaling through several divergent pathways initiating signals related to chemotaxis, cell survival and/or proliferation, increase in intracellular calcium, and gene transcription. CXCR4 is expressed on multiple cell types including lymphocytes, hematopoietic stem cells, endothelial and epithelial cells, and cancer cells. One of the most intriguing and perhaps important roles that CKs and the CK receptors have is in regulating metastasis. Here, CK receptors may potentially facilitate tumor dissemination at each of the key steps of metastasis, including adherence of tumor cells to endothelium, extravasation from blood vessels, metastatic colonization, angiogenesis, proliferation, and protection from the host response via activation of key survival pathways such as ERK/MAPK, PI-3K/Akt/mTOR, or Jak/STAT, etc. In addition, it is increasingly recognized that CKs play an important role in facilitating communication between cancer cells and non-neoplatic cells in the tumor microenvironment (TME), including endothelial cells and fibroblasts, promoting the infiltration, activation of neutrophils, and tumor-associated macrophages within the TME. In this review, we mainly focus on the roles of chemokines CXCL12 and its cognate receptors CXCR4 as they pertain to cancer progression. In particular, we summarizes our current understanding regarding the contribution of CXCR4 and SDF-1 to gastrointestinal tumor behavior and its role in local progression, dissemination, and immune evasion of tumor cells. Also, describes recent therapeutic approaches that target these receptors or their ligands.

  16. Acute alcohol intoxication suppresses the pulmonary ELR-negative CXC chemokine response to lipopolysaccharide.

    PubMed

    Happel, Kyle I; Rudner, Xiaowen; Quinton, Lee J; Movassaghi, Jennifer L; Clark, Charles; Odden, Anthony R; Zhang, Ping; Bagby, Gregory J; Nelson, Steve; Shellito, Judd E

    2007-08-01

    Alcohol abuse impairs the pulmonary immune response to infection and increases the morbidity and mortality of bacterial pneumonia. Acute alcohol intoxication suppresses lung expression of CXC chemokines bearing the Glu-Leu-Arg motif (ELR+) following lipopolysaccharide (LPS) challenge, but its effect on the structurally related ELR- CXC chemokines, which attract T cells, is unknown. We therefore investigated the effect of acute alcohol intoxication on the pulmonary response to intratracheal (i.t.) LPS challenge for the ELR- CXC chemokines monokine induced by gamma (MIG or CXCL9), interferon-inducible protein 10 (IP-10 or CXCL10), and interferon-inducible T cell alpha chemoattractant (I-TAC or CXCL11). Male C57BL/6 or C3H/HeN mice were given an intraperitoneal injection of ethanol (3.0 g/kg) or phosphate buffered saline 30 min before i.t. LPS challenge. Chemokine mRNA transcripts were measured at 0, 2, 6, and 16 h. Acute alcohol intoxication inhibited the lung's expression of all three chemokine genes in response to LPS. Lung IFN-gamma mRNA was also inhibited by acute intoxication over the same time course. The in vitro effect of ethanol on chemokine secretion was further studied in the MH-S alveolar macrophage cell line. IP-10, MIG, and I-TAC in response to LPS were enhanced by exogenous interferon (IFN)-gamma, and these responses were blunted by exposure to ethanol. Alcohol exposure did not affect MH-S cell nuclear factor kappa beta p65 nuclear localization during challenge, despite dose-dependent inhibition of Erk 1/2 phosphorylation. In addition, phospho-signal transduction and activator of transcription 1 was not decreased in the presence of acute ethanol, thereby indicating that acute intoxication does not affect IFN-gamma signaling in MH-S cells. Recruitment of CD3+ T cells into the alveolar space 4 days after LPS challenge was moderately impaired by acute ethanol intoxication. These results implicate acute ethanol intoxication as a significant inhibitor of

  17. Chemokine-cytokine cross-talk. The ELR+ CXC chemokine LIX (CXCL5) amplifies a proinflammatory cytokine response via a phosphatidylinositol 3-kinase-NF-kappa B pathway.

    PubMed

    Chandrasekar, Bysani; Melby, Peter C; Sarau, Henry M; Raveendran, Muthuswamy; Perla, Rao P; Marelli-Berg, Federica M; Dulin, Nickolai O; Singh, Ishwar S

    2003-02-14

    It is well established that cytokines can induce the production of chemokines, but the role of chemokines in the regulation of cytokine expression has not been fully investigated. Exposure of rat cardiac-derived endothelial cells (CDEC) to lipopolysaccharide-induced CXC chemokine (LIX), and to a lesser extent to KC and MIP-2, activated NF-kappaB and induced kappaB-driven promoter activity. LIX did not activate Oct-1. LIX-induced interleukin-1beta and tumor necrosis factor-alpha promoter activity, and up-regulated mRNA expression. Increased transcription and mRNA stability both contributed to cytokine expression. LIX-mediated cytokine gene transcription was inhibited by interleukin-10. Transient overexpression of kinase-deficient NF-kappaB-inducing kinase (NIK) and IkappaB kinase (IKK), and dominant negative IkappaB significantly inhibited LIX-mediated NF-kappaB activation in rat CDEC. Inhibition of G(i) protein-coupled signal transduction, poly(ADP-ribose) polymerase, phosphatidylinositol 3-kinase, and the 26 S proteasome significantly inhibited LIX-mediated NF-kappaB activation and cytokine gene transcription. Blocking CXCR2 attenuated LIX-mediated kappaB activation and kappaB-driven promoter activity in rat CDEC that express both CXCR1 and -2, and abrogated its activation in mouse CDEC that express only CXCR2. These results indicate that LIX activates NF-kappaB and induces kappaB-responsive proinflammatory cytokines via either CXCR1 or CXCR2, and involved phosphatidylinositol 3-kinase, NIK, IKK, and IkappaB. Thus, in addition to attracting and activating neutrophils, the ELR(+) CXC chemokines amplify the inflammatory cascade, stimulating local production of cytokines that have negative inotropic and proapoptotic effects.

  18. The DRF motif of CXCR6 as chemokine receptor adaptation to adhesion

    PubMed Central

    Koenen, Andrea; Babendreyer, Aaron; Schumacher, Julian; Pasqualon, Tobias; Schwarz, Nicole; Seifert, Anke; Deupi, Xavier

    2017-01-01

    The CXC-chemokine receptor 6 (CXCR6) is a class A GTP-binding protein-coupled receptor (GPCRs) that mediates adhesion of leukocytes by interacting with the transmembrane cell surface-expressed chemokine ligand 16 (CXCL16), and also regulates leukocyte migration by interacting with the soluble shed variant of CXCL16. In contrast to virtually all other chemokine receptors with chemotactic activity, CXCR6 carries a DRF motif instead of the typical DRY motif as a key element in receptor activation and G protein coupling. In this work, modeling analyses revealed that the phenylalanine F3.51 in CXCR6 might have impact on intramolecular interactions including hydrogen bonds by this possibly changing receptor function. Initial investigations with embryonic kidney HEK293 cells and further studies with monocytic THP-1 cells showed that mutation of DRF into DRY does not influence ligand binding, receptor internalization, receptor recycling, and protein kinase B (AKT) signaling. Adhesion was slightly decreased in a time-dependent manner. However, CXCL16-induced calcium signaling and migration were increased. Vice versa, when the DRY motif of the related receptor CX3CR1 was mutated into DRF the migratory response towards CX3CL1 was diminished, indicating that the presence of a DRF motif generally impairs chemotaxis in chemokine receptors. Transmembrane and soluble CXCL16 play divergent roles in homeostasis, inflammation, and cancer, which can be beneficial or detrimental. Therefore, the DRF motif of CXCR6 may display a receptor adaptation allowing adhesion and cell retention by transmembrane CXCL16 but reducing the chemotactic response to soluble CXCL16. This adaptation may avoid permanent or uncontrolled recruitment of inflammatory cells as well as cancer metastasis. PMID:28267793

  19. International Union of Basic and Clinical Pharmacology. [corrected]. LXXXIX. Update on the extended family of chemokine receptors and introducing a new nomenclature for atypical chemokine receptors.

    PubMed

    Bachelerie, Francoise; Ben-Baruch, Adit; Burkhardt, Amanda M; Combadiere, Christophe; Farber, Joshua M; Graham, Gerard J; Horuk, Richard; Sparre-Ulrich, Alexander Hovard; Locati, Massimo; Luster, Andrew D; Mantovani, Alberto; Matsushima, Kouji; Murphy, Philip M; Nibbs, Robert; Nomiyama, Hisayuki; Power, Christine A; Proudfoot, Amanda E I; Rosenkilde, Mette M; Rot, Antal; Sozzani, Silvano; Thelen, Marcus; Yoshie, Osamu; Zlotnik, Albert

    2014-01-01

    Sixteen years ago, the Nomenclature Committee of the International Union of Pharmacology approved a system for naming human seven-transmembrane (7TM) G protein-coupled chemokine receptors, the large family of leukocyte chemoattractant receptors that regulates immune system development and function, in large part by mediating leukocyte trafficking. This was announced in Pharmacological Reviews in a major overview of the first decade of research in this field [Murphy PM, Baggiolini M, Charo IF, Hébert CA, Horuk R, Matsushima K, Miller LH, Oppenheim JJ, and Power CA (2000) Pharmacol Rev 52:145-176]. Since then, several new receptors have been discovered, and major advances have been made for the others in many areas, including structural biology, signal transduction mechanisms, biology, and pharmacology. New and diverse roles have been identified in infection, immunity, inflammation, development, cancer, and other areas. The first two drugs acting at chemokine receptors have been approved by the U.S. Food and Drug Administration (FDA), maraviroc targeting CCR5 in human immunodeficiency virus (HIV)/AIDS, and plerixafor targeting CXCR4 for stem cell mobilization for transplantation in cancer, and other candidates are now undergoing pivotal clinical trials for diverse disease indications. In addition, a subfamily of atypical chemokine receptors has emerged that may signal through arrestins instead of G proteins to act as chemokine scavengers, and many microbial and invertebrate G protein-coupled chemokine receptors and soluble chemokine-binding proteins have been described. Here, we review this extended family of chemokine receptors and chemokine-binding proteins at the basic, translational, and clinical levels, including an update on drug development. We also introduce a new nomenclature for atypical chemokine receptors with the stem ACKR (atypical chemokine receptor) approved by the Nomenclature Committee of the International Union of Pharmacology and the Human Genome

  20. International Union of Pharmacology. LXXXIX. Update on the Extended Family of Chemokine Receptors and Introducing a New Nomenclature for Atypical Chemokine Receptors

    PubMed Central

    Bachelerie, Francoise; Ben-Baruch, Adit; Burkhardt, Amanda M.; Combadiere, Christophe; Farber, Joshua M.; Graham, Gerard J.; Horuk, Richard; Sparre-Ulrich, Alexander Hovard; Locati, Massimo; Luster, Andrew D.; Mantovani, Alberto; Matsushima, Kouji; Nibbs, Robert; Nomiyama, Hisayuki; Power, Christine A.; Proudfoot, Amanda E. I.; Rosenkilde, Mette M.; Rot, Antal; Sozzani, Silvano; Thelen, Marcus; Yoshie, Osamu; Zlotnik, Albert

    2014-01-01

    Sixteen years ago, the Nomenclature Committee of the International Union of Pharmacology approved a system for naming human seven-transmembrane (7TM) G protein-coupled chemokine receptors, the large family of leukocyte chemoattractant receptors that regulates immune system development and function, in large part by mediating leukocyte trafficking. This was announced in Pharmacological Reviews in a major overview of the first decade of research in this field [Murphy PM, Baggiolini M, Charo IF, Hébert CA, Horuk R, Matsushima K, Miller LH, Oppenheim JJ, and Power CA (2000) Pharmacol Rev 52:145–176]. Since then, several new receptors have been discovered, and major advances have been made for the others in many areas, including structural biology, signal transduction mechanisms, biology, and pharmacology. New and diverse roles have been identified in infection, immunity, inflammation, development, cancer, and other areas. The first two drugs acting at chemokine receptors have been approved by the U.S. Food and Drug Administration (FDA), maraviroc targeting CCR5 in human immunodeficiency virus (HIV)/AIDS, and plerixafor targeting CXCR4 for stem cell mobilization for transplantation in cancer, and other candidates are now undergoing pivotal clinical trials for diverse disease indications. In addition, a subfamily of atypical chemokine receptors has emerged that may signal through arrestins instead of G proteins to act as chemokine scavengers, and many microbial and invertebrate G protein-coupled chemokine receptors and soluble chemokine-binding proteins have been described. Here, we review this extended family of chemokine receptors and chemokine-binding proteins at the basic, translational, and clinical levels, including an update on drug development. We also introduce a new nomenclature for atypical chemokine receptors with the stem ACKR (atypical chemokine receptor) approved by the Nomenclature Committee of the International Union of Pharmacology and the Human

  1. Chemokines in Innate and Adaptive Granuloma Formation

    PubMed Central

    Chensue, Stephen W.

    2012-01-01

    Granulomas are cellular inflammations that vary widely in histologic appearance depending upon the inciting agent and immunologic status of the responding host. Despite their heterogeneity, granulomas are at their core an ancient innate sequestration response characterized by the accumulation of mononuclear phagocytes. In fact, this innate cellular response was first observed by Metchnikov in simple invertebrates. Among higher vertebrates, environmental pressures have resulted in the evolution of more sophisticated adaptive immune responses which can be superimposed upon and modify the character of granulomatous inflammation. Compared to immune responses that rapidly neutralize and eliminate infectious agents, the granuloma represents a less desirable “fall back” response which still has value to the host but can be co-opted by certain infectious agents and contribute to bystander organ damage. Understanding granulomas requires an analysis of the complex interplay of innate and adaptive molecular signals that govern the focal accumulation and activity of their cellular components. Among these signals, small molecular weight chemoattractant proteins known as chemokines are potentially important contributors as they participate in both directing leukocyte migration and function. This tract will discuss the contribution of chemokines to the development of innate and adaptive granuloma formation, as well as describe their relationship to more recently evolved cytokines generated during adaptive immune responses. PMID:23444049

  2. Field Crickets Compensate for Unattractive Static Long-Distance Call Components by Increasing Dynamic Signalling Effort.

    PubMed

    McAuley, Emily M; Bertram, Susan M

    2016-01-01

    The evolution of multiple sexual signals presents a dilemma since individuals selecting a mate should pay attention to the most honest signal and ignore the rest; however, multiple signals may evolve if, together, they provide more information to the receiver than either one would alone. Static and dynamic signals, for instance, can act as multiple messages, providing information on different aspects of signaller quality that reflect condition at different time scales. While the nature of static signals makes them difficult or impossible for individuals to augment, dynamic signals are much more susceptible to temporary fluctuations in effort. We investigated whether male Texas field crickets, Gryllus texensis, that produce unattractive static signals compensate by dynamically increasing their calling effort. Our findings lend partial support to the compensation hypothesis, as males that called at unattractive carrier frequencies (a static trait) spent more time calling each night (a dynamic trait). Interestingly, this finding was most pronounced in males that called with attractive pulse characteristics (static traits) but did not occur in males that called with unattractive pulse characteristics. Males that signalled with unattractive pulse characteristics (duration and pause) spent less time calling through the night. Our correlative findings on wild caught males suggest that only males that signal with attractive pulse characteristics may be able to afford to pay the costs of both trait exaggeration and increased calling effort to compensate for poor carrier frequencies.

  3. Field Crickets Compensate for Unattractive Static Long-Distance Call Components by Increasing Dynamic Signalling Effort

    PubMed Central

    McAuley, Emily M.

    2016-01-01

    The evolution of multiple sexual signals presents a dilemma since individuals selecting a mate should pay attention to the most honest signal and ignore the rest; however, multiple signals may evolve if, together, they provide more information to the receiver than either one would alone. Static and dynamic signals, for instance, can act as multiple messages, providing information on different aspects of signaller quality that reflect condition at different time scales. While the nature of static signals makes them difficult or impossible for individuals to augment, dynamic signals are much more susceptible to temporary fluctuations in effort. We investigated whether male Texas field crickets, Gryllus texensis, that produce unattractive static signals compensate by dynamically increasing their calling effort. Our findings lend partial support to the compensation hypothesis, as males that called at unattractive carrier frequencies (a static trait) spent more time calling each night (a dynamic trait). Interestingly, this finding was most pronounced in males that called with attractive pulse characteristics (static traits) but did not occur in males that called with unattractive pulse characteristics. Males that signalled with unattractive pulse characteristics (duration and pause) spent less time calling through the night. Our correlative findings on wild caught males suggest that only males that signal with attractive pulse characteristics may be able to afford to pay the costs of both trait exaggeration and increased calling effort to compensate for poor carrier frequencies. PMID:27936045

  4. Chemokine induction by all-trans retinoic acid and arsenic trioxide in acute promyelocytic leukemia: triggering the differentiation syndrome.

    PubMed

    Luesink, Maaike; Pennings, Jeroen L A; Wissink, Willemijn M; Linssen, Peter C M; Muus, Petra; Pfundt, Rolph; de Witte, Theo J M; van der Reijden, Bert A; Jansen, Joop H

    2009-12-24

    In acute promyelocytic leukemia (APL), differentiation therapy with all-trans retinoic acid (ATRA) and/or arsenic trioxide can induce a differentiation syndrome (DS) with massive pulmonary infiltration of differentiating leukemic cells. Because chemokines are implicated in migration and extravasation of leukemic cells, chemokines might play a role in DS. ATRA stimulation of the APL cell line NB4 induced expression of multiple CC-chemokines (CCLs) and their receptors (> 19-fold), resulting in increased chemokine levels and chemotaxis. Induction of CCL2 and CCL24 was directly mediated by ligand-activated retinoic acid receptors. In primary leukemia cells derived from APL patients at diagnosis, ATRA induced chemokine production as well. Furthermore, in plasma of an APL patient with DS, we observed chemokine induction, suggesting that chemokines might be important in DS. Dexamethasone, which efficiently reduces pulmonary chemokine production, did not inhibit chemokine induction in APL cells. Finally, chemokine production was also induced by arsenic trioxide as single agent or in combination with ATRA. We propose that differentiation therapy may induce chemokine production in the lung and in APL cells, which both trigger migration of leukemic cells. Because dexamethasone does not efficiently reduce leukemic chemokine production, pulmonary infiltration of leukemic cells may induce an uncontrollable hyperinflammatory reaction in the lung.

  5. Differential effects of protein kinase C inhibitors on chemokine production in human synovial fibroblasts.

    PubMed Central

    Jordan, N. J.; Watson, M. L.; Yoshimura, T.; Westwick, J.

    1996-01-01

    1. Rheumatoid arthritis is associated with the accumulation and activation of selected populations of inflammatory cells within the arthritic joint. One putative signal for this process is the production, by resident cells, of a group of inflammatory mediators known as the chemokines. 2. The chemokines interleukin-8 (IL-8), monocyte chemotactic protein-1 (MCP-1) and RANTES (regulated on activation normal T-cell expressed and presumably secreted) are target-cell specific chemoattractants produced by synovial fibroblasts in response to stimulation with interleukin-1 alpha (IL-1 alpha) or tumour necrosis factor alpha (TNF alpha). The signalling pathways involved in their production are not well defined. We therefore used four different protein kinase C inhibitors to investigate the role of this kinase in the regulation of chemokine mRNA and protein expression in human cultured synovial fibroblasts. 3. The non-selective PKC inhibitor, staurosporine (1-300 nM) significantly increased the production of IL-1 alpha-induced IL-8 mRNA and protein. A specific PKC inhibitor, chelerythrine chloride (0.1-3 microM), also caused a small concentration-dependent increase in IL-8 mRNA and protein production. In contrast, 3-[1-[3-(amidinothio)propyl]-3-indoly]-4-(1-methyl-3-indolyl )- 1H-pyrrole-2,5-dione methanesulphonate (Ro 31-8220) and 2[1-(3-dimethylaminopropyl)-1H-indol-3-yl]-3-(1H-indol-3- yl)-maleimide (GF 109203X), two selective PKC inhibitors of the substituted bisindolylmaleimide family had a concentration-dependent biphasic effect on IL-1 alpha or TNF alpha-induced chemokine expression. At low concentrations they caused a stimulation in chemokine production, which was especially evident at the mRNA level. At higher concentrations both inhibited IL-1 alpha or TNF alpha-induced chemokine mRNA and protein production. Ro 31-8220 was 10 fold more potent than GF 109203X, with an IC50 of 1.6 +/- 0.08 microM (mean +/- s.e.mean, n = 4) for IL-1 alpha induced IL-8 production. Ro 31

  6. Increased Expression of the Chemokines CXCL1 and MIP-1a by Resident Brain Cells Precedes Neutrophil Infiltration in the Brain Following Prolonged Soman-Induced Status Epilepticus in Rats

    DTIC Science & Technology

    2011-05-01

    chemokine concentrations according to the manufacturer’s instructions. A volume of 25 μl of sample (94 ± 8 μg protein) per well, assayed in dupli- cate...STaRStation software (Applied Cytometry, Sacramento, CA). Values that were calculated by the assay to be below the minimum detectable concentration...The 12 hour time point was selected based on the peak expression times of the analytes from the multiplex assays . Free float fluorescent IHC

  7. Therapeutic implications of chemokine-mediated pathways in atherosclerosis: realistic perspectives and utopias.

    PubMed

    Apostolakis, Stavros; Amanatidou, Virginia; Spandidos, Demetrios A

    2010-09-01

    Current perspectives on the pathogenesis of atherosclerosis strongly support the involvement of inflammatory mediators in the establishment and progression of atherosclerostic lesions. Chemokine-mediated mechanisms are potent regulators of such processes by orchestrating the interactions of inflammatory cellular components of the peripheral blood with cellular components of the arterial wall. The increasing evidence supporting the role of chemokine pathways in atherosclerosis renders chemokine ligands and their receptors potential therapeutic targets. In the following review, we aim to highlight the special structural and functional features of chemokines and their receptors in respect to their roles in atherosclerosis, and examine to what extent available data can be applied in disease management practices.

  8. Citrullinated Chemokines in Rheumatoid Arthritis

    DTIC Science & Technology

    2015-10-01

    Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions...searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send...inflammatory properties in RA pathogenesis. 15. SUBJECT TERMS Citrullination, chemokines, chemotaxis, rheumatoid arthritis, immunology 16. SECURITY

  9. Structural basis of receptor sulfotyrosine recognition by a CC chemokine: the N-terminal region of CCR3 bound to CCL11/eotaxin-1.

    PubMed

    Millard, Christopher J; Ludeman, Justin P; Canals, Meritxell; Bridgford, Jessica L; Hinds, Mark G; Clayton, Daniel J; Christopoulos, Arthur; Payne, Richard J; Stone, Martin J

    2014-11-04

    Trafficking of leukocytes in immune surveillance and inflammatory responses is activated by chemokines engaging their receptors. Sulfation of tyrosine residues in peptides derived from the eosinophil chemokine receptor CCR3 dramatically enhances binding to cognate chemokines. We report the structural basis of this recognition and affinity enhancement. We describe the structure of a CC chemokine (CCL11/eotaxin-1) bound to a fragment of a chemokine receptor: residues 8–23 of CCR3, including two sulfotyrosine residues. We also show that intact CCR3 is sulfated and sulfation enhances receptor activity. The CCR3 sulfotyrosine residues form hydrophobic, salt bridge and cation-p interactions with residues that are highly conserved in CC chemokines. However, the orientation of the chemokine relative to the receptor N terminus differs substantially from those observed for two CXC chemokines, suggesting that initial binding of the receptor sulfotyrosine residues guides subsequent steps in receptor activation, thereby influencing the receptor conformational changes and signaling.

  10. Endogenous ligand bias by chemokines: implications at the front lines of infection and leukocyte trafficking.

    PubMed

    Zidar, David A

    2011-06-01

    Chemokine receptors are a group of homologous seven transmembrane receptors (7TMR) that direct cell migration. Their ligands comprise a family of proteins that share structural, biochemical, and physiological features to govern leukocyte trafficking. Multiple endogenous chemokines with overlapping function have evolved for the majority of chemokine receptors. This duplicity of ligands has traditionally been seen to confer physiologic redundancy, especially as it pertains to chemotaxis mediated through G-protein activation. Yet, several recent reports also suggest that chemokine receptors are capable of differential signaling in a ligand-specific manner. This review will explore emerging concepts related to ligand bias at chemokine receptors. Recent studies show that although the endogenous ligands of CCR7 have apparent equipotency for G-protein signaling, they differentially activate the G-protein coupled receptor kinase (GRK)/β-arrestin system to selectively control receptor desensitization. In contrast, similar studies using endogenous ligands for CCR5, a human immunodeficiency virus (HIV) co-receptor, suggest this receptor is not subject to ligand bias by its principle chemokines. Nonetheless, this receptor does appear to be capable of biased agonism by synthetic chemokine analogues. These observations provide compelling evidence that ligand bias exists both as a naturally relevant and therapeutically important phenomenon. This review will highlight the evidence for differential signaling by CCR7 and CCR5, speculate on the physiologic relevance, and discuss the rationale behind the development of biased agonists for the treatment of HIV infection.

  11. Increased signaling entropy in cancer requires the scale-free property of protein interaction networks

    PubMed Central

    Teschendorff, Andrew E.; Banerji, Christopher R. S.; Severini, Simone; Kuehn, Reimer; Sollich, Peter

    2015-01-01

    One of the key characteristics of cancer cells is an increased phenotypic plasticity, driven by underlying genetic and epigenetic perturbations. However, at a systems-level it is unclear how these perturbations give rise to the observed increased plasticity. Elucidating such systems-level principles is key for an improved understanding of cancer. Recently, it has been shown that signaling entropy, an overall measure of signaling pathway promiscuity, and computable from integrating a sample's gene expression profile with a protein interaction network, correlates with phenotypic plasticity and is increased in cancer compared to normal tissue. Here we develop a computational framework for studying the effects of network perturbations on signaling entropy. We demonstrate that the increased signaling entropy of cancer is driven by two factors: (i) the scale-free (or near scale-free) topology of the interaction network, and (ii) a subtle positive correlation between differential gene expression and node connectivity. Indeed, we show that if protein interaction networks were random graphs, described by Poisson degree distributions, that cancer would generally not exhibit an increased signaling entropy. In summary, this work exposes a deep connection between cancer, signaling entropy and interaction network topology. PMID:25919796

  12. Nandrolone reduces activation of Notch signaling in denervated muscle associated with increased Numb expression

    SciTech Connect

    Liu, Xin-Hua; Yao, Shen; Qiao, Rui-Fang; Levine, Alice C.; Kirschenbaum, Alexander; Pan, Jiangping; Wu, Yong; Qin, Weiping; Bauman, William A.; Cardozo, Christopher P.

    2011-10-14

    Highlights: {yields} Nerve transection increased Notch signaling in paralyzed muscle. {yields} Nandrolone prevented denervation-induced Notch signaling. {yields} Nandrolone induced the expression of an inhibitor of the Notch signaling, Numb. {yields} Reduction of denervation-induced Notch signaling by nandrolone is likely through upregulation of Numb. -- Abstract: Nandrolone, an anabolic steroid, slows denervation-atrophy in rat muscle. The molecular mechanisms responsible for this effect are not well understood. Androgens and anabolic steroids activate Notch signaling in animal models of aging and thereby mitigate sarcopenia. To explore the molecular mechanisms by which nandrolone prevents denervation-atrophy, we investigated the effects of nandrolone on Notch signaling in denervated rat gastrocnemius muscle. Denervation significantly increased Notch activity reflected by elevated levels of nuclear Notch intracellular domain (NICD) and expression of Hey1 (a Notch target gene). Activation was greatest at 7 and 35 days after denervation but remained present at 56 days after denervation. Activation of Notch in denervated muscle was prevented by nandrolone associated with upregulated expression of Numb mRNA and protein. These data demonstrate that denervation activates Notch signaling, and that nandrolone abrogates this response associated with increased expression of Numb, suggesting a potential mechanism by which nandrolone reduces denervation-atrophy.

  13. Stoichiometry and geometry of the CXC chemokine receptor 4 complex with CXC ligand 12: molecular modeling and experimental validation.

    PubMed

    Kufareva, Irina; Stephens, Bryan S; Holden, Lauren G; Qin, Ling; Zhao, Chunxia; Kawamura, Tetsuya; Abagyan, Ruben; Handel, Tracy M

    2014-12-16

    Chemokines and their receptors regulate cell migration during development, immune system function, and in inflammatory diseases, making them important therapeutic targets. Nevertheless, the structural basis of receptor:chemokine interaction is poorly understood. Adding to the complexity of the problem is the persistently dimeric behavior of receptors observed in cell-based studies, which in combination with structural and mutagenesis data, suggest several possibilities for receptor:chemokine complex stoichiometry. In this study, a combination of computational, functional, and biophysical approaches was used to elucidate the stoichiometry and geometry of the interaction between the CXC-type chemokine receptor 4 (CXCR4) and its ligand CXCL12. First, relevance and feasibility of a 2:1 stoichiometry hypothesis was probed using functional complementation experiments with multiple pairs of complementary nonfunctional CXCR4 mutants. Next, the importance of dimers of WT CXCR4 was explored using the strategy of dimer dilution, where WT receptor dimerization is disrupted by increasing expression of nonfunctional CXCR4 mutants. The results of these experiments were supportive of a 1:1 stoichiometry, although the latter could not simultaneously reconcile existing structural and mutagenesis data. To resolve the contradiction, cysteine trapping experiments were used to derive residue proximity constraints that enabled construction of a validated 1:1 receptor:chemokine model, consistent with the paradigmatic two-site hypothesis of receptor activation. The observation of a 1:1 stoichiometry is in line with accumulating evidence supporting monomers as minimal functional units of G protein-coupled receptors, and suggests transmission of conformational changes across the dimer interface as the most probable mechanism of altered signaling by receptor heterodimers.

  14. [The diagnostic role of chemokines and their receptors in chronic hepatitis C].

    PubMed

    Sysoev, K A; Chukhlovin, A B; Totolian, A A

    2013-02-01

    The chronic hepatitis C is characterized by the increase of inflammatory disorders and progression of fibrosis of liver The corresponding immunologic mechanisms of hepatic lesions are still undiscovered. The actual review presents the analysis of scientific publications and genuine research data concerning the role of chemokines in pathogenesis of chronic hepatitis C. The chemokines are small cationic proteins enhancing transit and precipitation of migrating cells (leucocytes mainly) in tissues and organs. The significant role of chemokines in tissue homeostasis, in case of inflammation, wound healing and cell proliferation is demonstrated. The particular kinds of chemokines are produced by different types of cells and impact target cells through their specific receptors. According the data of various studies, chemokines and chemokine receptors of CC-families and CXC-families are involved in fibrosing processes and anti-inflammatory activation of hepatic-biliary system under chronic hepatitis C. The diversity of producers and targets of chemokines in liver is very pronounced: hepatocytes, stellar cells, endothelium cells, macrophages (Kupffer cells), dendritic cells, lymphocytes and monocytes. The review considers pathogenesis of chronic hepatitis C from the standpoint of participation of chemokines and chemokine receptors at different stages of cellular transit. The most important cellpopulations involved into pathologic changes under chronic hepatitis C are characterized. The decrease of expression of such gens as CCR1, CCR2, CCR3, and CCR5 in blood leucocytes deserves additional studies to establish their diagnostic values as a marker of disorders of immune system in patients with chronic hepatitis C.

  15. Chemokines in Cancer Development and Progression and Their Potential as Targeting Molecules for Cancer Treatment

    PubMed Central

    Mukaida, Naofumi; Sasaki, So-ichiro; Baba, Tomohisa

    2014-01-01

    Chemokines were initially identified as bioactive substances, which control the trafficking of inflammatory cells including granulocytes and monocytes/macrophages. Moreover, chemokines have profound impacts on other types of cells associated with inflammatory responses, such as endothelial cells and fibroblasts. These observations would implicate chemokines as master regulators in various inflammatory responses. Subsequent studies have further revealed that chemokines can regulate the movement of a wide variety of immune cells including lymphocytes, natural killer cells, and dendritic cells in both physiological and pathological conditions. These features endow chemokines with crucial roles in immune responses. Furthermore, increasing evidence points to the vital effects of several chemokines on the proliferative and invasive properties of cancer cells. It is widely acknowledged that cancer develops and progresses to invade and metastasize in continuous interaction with noncancerous cells present in cancer tissues, such as macrophages, lymphocytes, fibroblasts, and endothelial cells. The capacity of chemokines to regulate both cancerous and noncancerous cells highlights their crucial roles in cancer development and progression. Here, we will discuss the roles of chemokines in carcinogenesis and the possibility of chemokine targeting therapy for the treatment of cancer. PMID:24966464

  16. Chemokines and their receptors in the allergic airway inflammatory process.

    PubMed

    Velazquez, Juan Raymundo; Teran, Luis Manuel

    2011-08-01

    The development of the allergic airway disease conveys several cell types, such as T-cells, eosinophils, mast cells, and dendritic cells, which act in a special and temporal synchronization. Cellular mobilization and its complex interactions are coordinated by a broad range of bioactive mediators known as chemokines. These molecules are an increasing family of small proteins with common structural motifs and play an important role in the recruitment and cell activation of both leukocytes and resident cells at the allergic inflammatory site via their receptors. Trafficking and recruitment of cell populations with specific chemokines receptors assure the presence of reactive allergen-specific T-cells in the lung, and therefore the establishment of an allergic inflammatory process. Different approaches directed against chemokines receptors have been developed during the last decades with promising therapeutic results in the treatment of asthma. In this review we explore the role of the chemokines and chemokine receptors in allergy and asthma and discuss their potential as targets for therapy.

  17. Chemokine response in mice infected with Mycobacterium tuberculosis.

    PubMed Central

    Rhoades, E R; Cooper, A M; Orme, I M

    1995-01-01

    We show here that infection of murine macrophages with various strains of Mycobacterium tuberculosis induces the rapid in vitro expression of genes encoding chemokines macrophage inflammatory protein 1 alpha and macrophage inflammatory protein 2, which recruit neutrophils to sites of infection, and macrophage-recruiting chemokines 10-kDa, interferon-inducible protein (IP-10) and macrophage chemotactic protein 1. Three strains of M. tuberculosis, Erdman and the clinical isolates CSU 22 and CSU 46, induced similar levels of secretion of macrophage chemotactic protein 1 from infected macrophage monolayers; however, the Erdman strain failed to induce levels of secretion of tumor necrosis factor alpha similar to those induced by either CSU 22 or CSU 46. Using a low-dose aerosol infection model, we also found that while the Erdman strain induced negligible increases in chemokine mRNA levels in the lungs, infection with either CSU 22 or CSU 46 resulted in greater levels of mRNA production for all four chemokines tested. The growth of these strains in the lungs was, however, equally well contained by acquired host immunity. These data allow us to hypothesize that the chemokine response in the lungs probably does not control the protective granulomatous response and that perhaps other T-cell- or macrophage-associated cytokines such as tumor necrosis factor alpha or interleukin 12 may be involved in this process. PMID:7558294

  18. Disruption of mTORC1 in Macrophages Decreases Chemokine Gene Expression and Atherosclerosis

    PubMed Central

    Ai, Ding; Jiang, Hongfeng; Westerterp, Marit; Murphy, Andrew J.; Wang, Mi; Ganda, Anjali; Abramowicz, Sandra; Welch, Carrie; Almazan, Felicidad; Zhu, Yi; Miller, Yury I; Tall, Alan R.

    2014-01-01

    Rationale The mammalian target of rapamycin complex 1 (mTORC1) inhibitor, rapamycin, has been shown to decrease atherosclerosis, even while increasing plasma LDL levels. This suggests an anti-atherogenic effect possibly mediated by modulation of inflammatory responses in atherosclerotic plaques. Objective To assess the role of macrophage mTORC1 in atherogenesis. Methods and Results We transplanted bone marrow from mice in which a key mTORC1 adaptor, Raptor, was deleted in macrophages by Cre/loxP recombination (Mac-RapKO mice) into Ldlr-/- mice and then fed them the Western-type diet (WTD). Atherosclerotic lesions from Mac-RapKO mice showed decreased infiltration of macrophages, lesion size and chemokine gene expression compared with control mice. Treatment of macrophages with minimally modified LDL (mmLDL) resulted in increased levels of chemokine mRNAs and STAT3 phosphorylation; these effects were reduced in Mac-RapKO macrophages. While wild-type and Mac-RapKO macrophages showed similar STAT3 phosphorylation on Tyr705, Mac-RapKO macrophages showed decreased STAT3 Ser727 phosphorylation in response to mmLDL treatment and decreased Ccl2 promoter binding of STAT3. Conclusions The results demonstrate cross-talk between nutritionally-induced mTORC1 signaling and mmLDL-mediated inflammatory signaling via combinatorial phosphorylation of STAT3 in macrophages, leading to increased STAT3 activity on the CCL2 (MCP-1)promoter with pro-atherogenic consequences. PMID:24687132

  19. Cytokines and chemokines in neuromyelitis optica: pathogenetic and therapeutic implications.

    PubMed

    Uzawa, Akiyuki; Mori, Masahiro; Masahiro, Mori; Kuwabara, Satoshi

    2014-01-01

    Neuromyelitis optica (NMO) is characterized by severe optic neuritis and longitudinally extensive transverse myelitis. The discovery of an NMO-specific autoantibody to the aquaporin-4 (AQP4) water channel has improved knowledge of NMO pathogenesis. Many studies have focused on inflammatory and pathological biomarkers of NMO, including cytokines and chemokines. Increased concentrations of T helper (Th)17- and Th2-related cytokines and chemokines may be essential factors for developing NMO inflammatory lesions. For example, interleukin-6 could play important roles in NMO pathogenesis, as it is involved in the survival of plasmablasts that produce anti-AQP4 antibody in peripheral circulation and in the enhancement of inflammation in the central nervous system. Therefore, assessment of these useful biomarkers may become a supportive criterion for diagnosing NMO. Significant advances in the understanding of NMO pathogenesis will lead to the development of novel treatment strategies. This review focuses on the current advances in NMO immunological research, particularly that of cytokines and chemokines.

  20. Chemokine gene variants in schizophrenia.

    PubMed

    Dasdemir, Selcuk; Kucukali, Cem Ismail; Bireller, Elif Sinem; Tuzun, Erdem; Cakmakoglu, Bedia

    2016-08-01

    Background Chemokines are known to play a major role in driving inflammation and immune responses in several neuroinflammatory diseases, including multiple sclerosis, Alzheimer's disease and Parkinson's disease. Inflammation has also been implicated in the pathogenesis of schizophrenia. Aim We aimed to investigate a potential link between chemokines and schizophrenia and analyze the role of MCP-1-A2518G, SDF-1-3'A, CCR5-delta32, CCR5-A55029G, CXCR4-C138T and CCR2-V64I gene polymorphisms in the Turkish population. Methods Genotyping was conducted by PCR-RFLP based on 140 patients and 123 unrelated healthy controls to show the relation between chemokine gene variants and schizophrenia risk. Results Frequencies of CCR5-A55029G A genotypes and CCR5-A55029G AG genotypes were found higher in patients than the controls and even also CCR2-V64I WT: CCR5-A55029G A and CCR2-V64I 64I: CCR5-A55029G A haplotypes significantly associated according to Bonferroni correction. However, no significant association was found for any of the other polymorphisms with the risk of schizophrenia. Conclusions Our findings suggest that CCR5-A55029G polymorphisms and CCR2-V64I WT: CCR5-A55029G A and CCR2-V64I 64I: CCR5-A55029G A haplotypes might have association with schizophrenia pathogenesis.

  1. Midazolam sedation increases fluctuation and synchrony of the resting brain BOLD signal.

    PubMed

    Kiviniemi, Vesa J; Haanpää, Hannu; Kantola, Juha-Heikki; Jauhiainen, Jukka; Vainionpää, Vilho; Alahuhta, Seppo; Tervonen, Osmo

    2005-05-01

    The blood oxygen level-dependent (BOLD) magnetic resonance signal of functional brain cortices is dominated by very low frequency (VLF) fluctuations in anesthetized child patients. The temporal synchrony of the BOLD signal is also higher in anesthetized children compared with awake adults. The origin of the synchronous fluctuations can be related to maturation, pathological status or the anesthesia used in the imaging. Two of the three confounding variables (maturation and pathology) were controlled in this study. The effect of midazolam (4+/-0.8 mg) sedation on the BOLD signal was assessed in 12 healthy adults (aged 24+/-1.5 years) at 1.5 T. The VLF fluctuation power and temporal synchrony of the BOLD signal increased significantly after the sedation in the auditory and visual cortices. The fast Fourier transformation power spectral baseline fit parameters of the BOLD signal were also found to change significantly after sedation. It is concluded that the VLF fluctuation and temporal synchrony of the BOLD signal become increased after sedation in functional brain regions.

  2. Supramolecular Nanofibers Enhance Growth Factor Signaling by Increasing Lipid Raft Mobility

    SciTech Connect

    Newcomb, Christina J.; Sur, Shantanu; Lee, Sungsoo S.; Yu, Jeong Min; Zhou, Yan; Snead, Malcolm L.; Stupp, Samuel I.

    2016-04-12

    The nanostructures of self-assembling biomaterials have been previously designed to tune the release of growth factors in order to optimize biological repair and regeneration. We report here on the discovery that weakly cohesive peptide nanostructures in terms of intermolecular hydrogen bonding, when combined with low concentrations of osteogenic growth factor, enhance both BMP-2 and Wnt mediated signaling in myoblasts and bone marrow stromal cells, respectively. Conversely, analogous nanostructures with enhanced levels of internal hydrogen bonding and cohesion lead to an overall reduction in BMP-2 signaling. We propose that the mechanism for enhanced growth factor signaling by the nanostructures is related to their ability to increase diffusion within membrane lipid rafts. The phenomenon reported here could lead to new nanomedicine strategies to mediate growth factor signaling for translational targets.

  3. Acidic pH stimulates the production of the angiogenic CXC chemokine, CXCL8 (interleukin-8), in human adult mesenchymal stem cells via the extracellular signal-regulated kinase, p38 mitogen-activated protein kinase, and NF-kappaB pathways.

    PubMed

    Bischoff, David S; Zhu, Jian-Hua; Makhijani, Nalini S; Yamaguchi, Dean T

    2008-07-01

    Blood vessel injury results in limited oxygen tension and diffusion leading to hypoxia, increased anaerobic metabolism, and elevated production of acidic metabolites that cannot be easily removed due to the reduced blood flow. Therefore, an acidic extracellular pH occurs in the local microenvironment of disrupted bone. The potential role of acidic pH and glu-leu-arg (ELR(+)) CXC chemokines in early events in bone repair was studied in human mesenchymal stem cells (hMSCs) treated with medium of decreasing pH (7.4, 7.0, 6.7, and 6.4). The cells showed a reciprocal increase in CXCL8 (interleukin-8, IL-8) mRNA levels as extracellular pH decreased. At pH 6.4, CXCL8 mRNA was induced >60x in comparison to levels at pH 7.4. hMSCs treated with osteogenic medium (OGM) also showed an increase in CXCL8 mRNA with decreasing pH; although, at a lower level than that seen in cells grown in non-OGM. CXCL8 protein was secreted into the medium at all pHs with maximal induction at pH 6.7. Inhibition of the G-protein-coupled receptor alpha, G(alphai), suppressed CXCL8 levels in response to acidic pH; whereas phospholipase C inhibition had no effect on CXCL8. The use of specific mitogen-activated protein kinase (MAPK) signal transduction inhibitors indicated that the pH-dependent increase in CXCL8 mRNA is due to activation of ERK and p38 pathways. The JNK pathway was not involved. NF-kappaB inhibition resulted in a decrease in CXCL8 levels in hMSCs grown in non-OGM. However, OGM-differentiated hMSCs showed an increase in CXCL8 levels when treated with the NF-kappaB inhibitor PDTC, a pyrrolidine derivative of dithiocarbamate.

  4. Increased bone morphogenetic protein signaling contributes to age-related declines in neurogenesis and cognition

    PubMed Central

    Meyers, Emily A.; Gobeske, Kevin T.; Bond, Allison M.; Jarrett, Jennifer C.; Peng, Chian-Yu; Kessler, John A.

    2015-01-01

    Aging is associated with decreased neurogenesis in the hippocampus and diminished hippocampus-dependent cognitive functions. Expression of bone morphogenetic protein 4 (BMP4) increases with age by more than 10-fold in the mouse dentate gyrus while levels of the BMP inhibitor, noggin, decrease. This results in a profound 30-fold increase in phosphorylated-SMAD1/5/8, the effector of canonical BMP signaling. Just as observed in mice, a profound increase in expression of BMP4 is observed in the dentate gyrus of humans with no known cognitive abnormalities. Inhibition of BMP signaling either by overexpression of noggin or transgenic manipulation not only increases neurogenesis in aging mice, but remarkably, is associated with a rescue of cognitive deficits to levels comparable to young mice. Additive benefits are observed when combining inhibition of BMP signaling and environmental enrichment. These findings indicate that increased BMP signaling contributes significantly to impairments in neurogenesis and to cognitive decline associated with aging, and identify this pathway as a potential druggable target for reversing age-related changes in cognition. PMID:26827654

  5. Nandrolone reduces activation of Notch signaling in denervated muscle associated with increased Numb expression.

    PubMed

    Liu, Xin-Hua; Yao, Shen; Qiao, Rui-Fang; Levine, Alice C; Kirschenbaum, Alexander; Pan, Jiangping; Wu, Yong; Qin, Weiping; Bauman, William A; Cardozo, Christopher P

    2011-10-14

    Nandrolone, an anabolic steroid, slows denervation-atrophy in rat muscle. The molecular mechanisms responsible for this effect are not well understood. Androgens and anabolic steroids activate Notch signaling in animal models of aging and thereby mitigate sarcopenia. To explore the molecular mechanisms by which nandrolone prevents denervation-atrophy, we investigated the effects of nandrolone on Notch signaling in denervated rat gastrocnemius muscle. Denervation significantly increased Notch activity reflected by elevated levels of nuclear Notch intracellular domain (NICD) and expression of Hey1 (a Notch target gene). Activation was greatest at 7 and 35 days after denervation but remained present at 56 days after denervation. Activation of Notch in denervated muscle was prevented by nandrolone associated with upregulated expression of Numb mRNA and protein. These data demonstrate that denervation activates Notch signaling, and that nandrolone abrogates this response associated with increased expression of Numb, suggesting a potential mechanism by which nandrolone reduces denervation-atrophy.

  6. Dragon enhances BMP signaling and increases transepithelial resistance in kidney epithelial cells.

    PubMed

    Xia, Yin; Babitt, Jodie L; Bouley, Richard; Zhang, Ying; Da Silva, Nicolas; Chen, Shanzhuo; Zhuang, Zhenjie; Samad, Tarek A; Brenner, Gary J; Anderson, Jennifer L; Hong, Charles C; Schneyer, Alan L; Brown, Dennis; Lin, Herbert Y

    2010-04-01

    The neuronal adhesion protein Dragon acts as a bone morphogenetic protein (BMP) coreceptor that enhances BMP signaling. Given the importance of BMP signaling in nephrogenesis and its putative role in the response to injury in the adult kidney, we studied the localization and function of Dragon in the kidney. We observed that Dragon localized predominantly to the apical surfaces of tubular epithelial cells in the thick ascending limbs, distal convoluted tubules, and collecting ducts of mice. Dragon expression was weak in the proximal tubules and glomeruli. In mouse inner medullary collecting duct (mIMCD3) cells, Dragon generated BMP signals in a ligand-dependent manner, and BMP4 is the predominant endogenous ligand for the Dragon coreceptor. In mIMCD3 cells, BMP4 normally signaled through BMPRII, but Dragon enhanced its signaling through the BMP type II receptor ActRIIA. Dragon and BMP4 increased transepithelial resistance (TER) through the Smad1/5/8 pathway. In epithelial cells isolated from the proximal tubule and intercalated cells of collecting ducts, we observed coexpression of ActRIIA, Dragon, and BMP4 but not BMPRII. Taken together, these results suggest that Dragon may enhance BMP signaling in renal tubular epithelial cells and maintain normal renal physiology.

  7. KRIT1 protein depletion modifies endothelial cell behavior via increased vascular endothelial growth factor (VEGF) signaling.

    PubMed

    DiStefano, Peter V; Kuebel, Julia M; Sarelius, Ingrid H; Glading, Angela J

    2014-11-21

    Disruption of endothelial cell-cell contact is a key event in many cardiovascular diseases and a characteristic of pathologically activated vascular endothelium. The CCM (cerebral cavernous malformation) family of proteins (KRIT1 (Krev-interaction trapped 1), PDCD10, and CCM2) are critical regulators of endothelial cell-cell contact and vascular homeostasis. Here we show novel regulation of vascular endothelial growth factor (VEGF) signaling in KRIT1-depleted endothelial cells. Loss of KRIT1 and PDCD10, but not CCM2, increases nuclear β-catenin signaling and up-regulates VEGF-A protein expression. In KRIT1-depleted cells, increased VEGF-A levels led to increased VEGF receptor 2 (VEGFR2) activation and subsequent alteration of cytoskeletal organization, migration, and barrier function and to in vivo endothelial permeability in KRIT1-deficient animals. VEGFR2 activation also increases β-catenin phosphorylation but is only partially responsible for KRIT1 depletion-dependent disruption of cell-cell contacts. Thus, VEGF signaling contributes to modifying endothelial function in KRIT1-deficient cells and microvessel permeability in Krit1(+/-) mice; however, VEGF signaling is likely not the only contributor to disrupted endothelial cell-cell contacts in the absence of KRIT1.

  8. Feedback signals in myelodysplastic syndromes: increased self-renewal of the malignant clone suppresses normal hematopoiesis.

    PubMed

    Walenda, Thomas; Stiehl, Thomas; Braun, Hanna; Fröbel, Julia; Ho, Anthony D; Schroeder, Thomas; Goecke, Tamme W; Rath, Björn; Germing, Ulrich; Marciniak-Czochra, Anna; Wagner, Wolfgang

    2014-04-01

    Myelodysplastic syndromes (MDS) are triggered by an aberrant hematopoietic stem cell (HSC). It is, however, unclear how this clone interferes with physiologic blood formation. In this study, we followed the hypothesis that the MDS clone impinges on feedback signals for self-renewal and differentiation and thereby suppresses normal hematopoiesis. Based on the theory that the MDS clone affects feedback signals for self-renewal and differentiation and hence suppresses normal hematopoiesis, we have developed a mathematical model to simulate different modifications in MDS-initiating cells and systemic feedback signals during disease development. These simulations revealed that the disease initiating cells must have higher self-renewal rates than normal HSCs to outcompete normal hematopoiesis. We assumed that self-renewal is the default pathway of stem and progenitor cells which is down-regulated by an increasing number of primitive cells in the bone marrow niche--including the premature MDS cells. Furthermore, the proliferative signal is up-regulated by cytopenia. Overall, our model is compatible with clinically observed MDS development, even though a single mutation scenario is unlikely for real disease progression which is usually associated with complex clonal hierarchy. For experimental validation of systemic feedback signals, we analyzed the impact of MDS patient derived serum on hematopoietic progenitor cells in vitro: in fact, MDS serum slightly increased proliferation, whereas maintenance of primitive phenotype was reduced. However, MDS serum did not significantly affect colony forming unit (CFU) frequencies indicating that regulation of self-renewal may involve local signals from the niche. Taken together, we suggest that initial mutations in MDS particularly favor aberrant high self-renewal rates. Accumulation of primitive MDS cells in the bone marrow then interferes with feedback signals for normal hematopoiesis--which then results in cytopenia.

  9. Chemokine and chemokine receptor structure and interactions: implications for therapeutic strategies

    PubMed Central

    Kufareva, Irina; Salanga, Catherina L.; Handel, Tracy M.

    2015-01-01

    The control of cell migration by chemokines involves interactions with two types of receptors: seven transmembrane chemokine-type G protein-coupled receptors and cell surface or extracellular matrix associated glycosaminoglycans. Coordinated interaction of chemokines with both types of receptors is required for directional migration of cells in numerous physiological and pathological processes. Accumulated structural information, culminating most recently in the structure of a chemokine receptor in complex with a chemokine, has led to a view where chemokine oligomers bind to glycosaminoglycans through epitopes formed when chemokine subunits come together, while chemokine monomers bind to receptors in a pseudo two-step mechanism of receptor activation. Exploitation of this structural knowledge has and will continue to provide important information for therapeutic strategies, as described in this review. PMID:25708536

  10. Observation of increased ion cyclotron resonance signal duration through electric field perturbations.

    PubMed

    Kaiser, Nathan K; Bruce, James E

    2005-09-15

    Ion motion in Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) is complex and the subject of ongoing theoretical and experimental studies. Two predominant pathways for the loss of ICR signals are thought to include damping of cyclotron motion, in which ions lose kinetic energy and radially damp toward the center of the ICR cell, and dephasing of ion coherence, in which ions of like cyclotron frequency become distributed out of phase at similar cyclotron radii. Both mechanisms result in the loss of induced ion image current in FTICR-MS measurements and are normally inseparable during time-domain signal analysis. For conventional ICR measurements which take advantage of ion ensembles, maximization of the ion population size and density can produce the desired effect of increasing phase coherence of ions during cyclotron motion. However, this approach also presents the risk of coalescence of ion packets of similar frequencies. In general, ICR researchers in the past have lacked the tools necessary to distinguish or independently control dephasing and damping mechanisms for ICR signal loss. Nonetheless, the ability to impart greater phase coherence of ions in ICR measurements will allow significant advances in FTICR-MS research by improving the current understanding of ICR signal loss contributions of dephasing and damping of ion ensembles, increasing overall time-domain signal length, and possibly, resulting in more routine ultrahigh resolution measurements. The results presented here demonstrate the ability to employ a high density electron beam to perturb electric fields within the ICR cell during detection of cyclotron motion, in an approach we call electron-promoted ion coherence (EPIC). As such, EPIC reduces ICR signal degradation through loss of phase coherence, and much longer time-domain signals can be obtained. Our results demonstrate that time-domain signals can be extended by more than a factor of 4 with the implementation of EPIC, as

  11. Simulation study on effects of signaling network structure on the developmental increase in complexity

    SciTech Connect

    Keranen, Soile V.E.

    2003-04-02

    The developmental increase in structural complexity in multicellular life forms depends on local, often non-periodic differences in gene expression. These depend on a network of gene-gene interactions coded within the organismal genome. To better understand how genomic information generates complex expression patterns, I have modeled the pattern forming behavior of small artificial genomes in virtual blastoderm embryos. I varied several basic properties of these genomic signaling networks, such as the number of genes, the distributions of positive (inductive) and negative (repressive) interactions, and the strengths of gene-gene interactions, and analyzed their effects on developmental pattern formation. The results show how even simple genomes can generate complex non-periodic patterns under suitable conditions. They also show how the frequency of complex patterns depended on the numbers and relative arrangements of positive and negative interactions. For example, negative co-regulation of signaling pathway components increased the likelihood of (complex) patterns relative to differential negative regulation of the pathway components. Interestingly, neither quantitative differences either in strengths of signaling interactions nor multiple response thresholds to signal concentration (as in morphogen gradients) were essential for formation of multiple, spatially unique cell types. Thus, with combinatorial code of gene regulation and hierarchical signaling interactions, it is theoretically possible to organize metazoan embryogenesis with just a small fraction of the metazoan genome. Because even small networks can generate complex patterns when they contain a suitable set of connections, evolution of metazoan complexity may have depended more on selection for favourable configurations of signaling interactions than on the increase in numbers of regulatory genes.

  12. New chemokine targets for asthma therapy.

    PubMed

    Garcia, Gilles; Godot, Véronique; Humbert, Marc

    2005-03-01

    Chemokines and chemokine receptors are part of a complex network of molecules that play a key role in leukocyte migration and activation. The chemokine family role is crucial in the immune system, orchestrating innate and acquired immune responses, but also in allergic inflammation. A subset of chemokines, including CCL11, CCL24, CCL26, CCL7, CCL13, CCL17, and CCL22 is highly expressed by the three main cell types involved in allergic inflammation: eosinophils, basophils, and Th2 lymphocytes. In vitro and in vivo experimental studies in murine models of asthma as well as evidence from patients with asthma confirm the role of these chemokines and their receptors, including CCR3, CCR4, and CCR8, establishing a subset of chemokine/chemokine receptor that is potentially important in allergic inflammation. Recent data support the concept that interfering with chemokines or chemokine receptors represents a new approach in allergy therapy. However, even if some of them have been shown to be effective in animal models, none is as yet used in human patients.

  13. Direct stimulation of bone mass by increased GH signalling in the osteoblasts of Socs2-/- mice.

    PubMed

    Dobie, R; MacRae, V E; Huesa, C; van't Hof, R; Ahmed, S F; Farquharson, C

    2014-10-01

    The suppressor of cytokine signalling (Socs2(-/-))-knockout mouse is characterised by an overgrowth phenotype due to enhanced GH signalling. The objective of this study was to define the Socs2(-/-) bone phenotype and determine whether GH promotes bone mass via IGF1-dependent mechanisms. Despite no elevation in systemic IGF1 levels, increased body weight in 4-week-old Socs2(-/-) mice following GH treatment was associated with increased cortical bone area (Ct.Ar) (P<0.01). Furthermore, detailed bone analysis of male and female juvenile and adult Socs2(-/-) mice revealed an altered cortical and trabecular phenotype consistent with the known anabolic effects of GH. Indeed, male Socs2(-/-) mice had increased Ct.Ar (P<0.05) and thickness associated with increased strength. Despite this, there was no elevation in hepatic Igf1 expression, suggesting that the anabolic bone phenotype was the result of increased local GH action. Mechanistic studies showed that in osteoblasts and bone of Socs2(-/-) mice, STAT5 phosphorylation was significantly increased in response to GH. Conversely, overexpression of SOCS2 decreased GH-induced STAT5 signalling. Although an increase in Igf1 expression was observed in Socs2(-/-) osteoblasts following GH, it was not evident in vivo. Igf1 expression levels were not elevated in response to GH in 4-week-old mice and no alterations in expression was observed in bone samples of 6-week-old Socs2(-/-) mice. These studies emphasise the critical role of SOCS2 in controlling the local GH anabolic bone effects. We provide compelling evidence implicating SOCS2 in the regulation of GH osteoblast signalling and ultimately bone accrual, which maybe via mechanisms that are independent of IGF1 production in vivo.

  14. Expression of functional sphingosine-1 phosphate receptor-1 is reduced by B cell receptor signaling and increased by inhibition of PI3 kinase δ but not SYK or BTK in chronic lymphocytic leukemia cells.

    PubMed

    Till, Kathleen J; Pettitt, Andrew R; Slupsky, Joseph R

    2015-03-01

    BCR signaling pathway inhibitors such as ibrutinib, idelalisib, and fostamatinib (respective inhibitors of Bruton's tyrosine kinase, PI3Kδ, and spleen tyrosine kinase) represent a significant therapeutic advance in B cell malignancies, including chronic lymphocytic leukemia (CLL). These drugs are distinctive in increasing blood lymphocytes while simultaneously shrinking enlarged lymph nodes, suggesting anatomical redistribution of CLL cells from lymph nodes into the blood. However, the mechanisms underlying this phenomenon are incompletely understood. In this study, we showed that the egress receptor, sphingosine-1-phosphate (S1P) receptor 1 (S1PR1), was expressed at low levels in normal germinal centers and CLL lymph nodes in vivo but became upregulated on normal B cells and, to a variable and lesser extent, CLL cells following in vitro incubation in S1P-free medium. Spontaneous recovery of S1PR1 expression on normal B and CLL cells was prevented by BCR cross-linking, whereas treatment of CLL cells with idelalisib increased S1PR1 expression and migration toward S1P, the greatest increase occurring in cases with unmutated IgH V region genes. Intriguingly, ibrutinib and fostamatinib had no effect on S1PR1 expression or function. Conversely, chemokine-induced migration, which requires integrin activation and is essential for the entry of lymphocytes into lymph nodes as well as their retention, was blocked by ibrutinib and fostamatinib, but not idelalisib. In summary, our results suggest that different BCR signaling inhibitors redistribute CLL cells from lymph nodes into the blood through distinct mechanisms: idelalisib actively promotes egress by upregulating S1PR1, whereas fostamatinib and ibrutinib may reduce CLL cell entry and retention by suppressing chemokine-induced integrin activation.

  15. Real Diffusion-Weighted MRI Enabling True Signal Averaging and Increased Diffusion Contrast

    PubMed Central

    Eichner, Cornelius; Cauley, Stephen F; Cohen-Adad, Julien; Möller, Harald E; Turner, Robert; Setsompop, Kawin; Wald, Lawrence L

    2015-01-01

    This project aims to characterize the impact of underlying noise distributions on diffusion-weighted imaging. The noise floor is a well-known problem for traditional magnitude-based diffusion-weighted MRI (dMRI) data, leading to biased diffusion model fits and inaccurate signal averaging. Here, we introduce a total-variation-based algorithm to eliminate shot-to-shot phase variations of complex-valued diffusion data with the intention to extract real-valued dMRI datasets. The obtained real-valued diffusion data are no longer superimposed by a noise floor but instead by a zero-mean Gaussian noise distribution, yielding dMRI data without signal bias. We acquired high-resolution dMRI data with strong diffusion weighting and, thus, low signal-to-noise ratio. Both the extracted real-valued and traditional magnitude data were compared regarding signal averaging, diffusion model fitting and accuracy in resolving crossing fibers. Our results clearly indicate that real-valued diffusion data enables idealized conditions for signal averaging. Furthermore, the proposed method enables unbiased use of widely employed linear least squares estimators for model fitting and demonstrates an increased sensitivity to detect secondary fiber directions with reduced angular error. The use of phase-corrected, real-valued data for dMRI will therefore help to clear the way for more detailed and accurate studies of white matter microstructure and structural connectivity on a fine scale. PMID:26241680

  16. Real diffusion-weighted MRI enabling true signal averaging and increased diffusion contrast.

    PubMed

    Eichner, Cornelius; Cauley, Stephen F; Cohen-Adad, Julien; Möller, Harald E; Turner, Robert; Setsompop, Kawin; Wald, Lawrence L

    2015-11-15

    This project aims to characterize the impact of underlying noise distributions on diffusion-weighted imaging. The noise floor is a well-known problem for traditional magnitude-based diffusion-weighted MRI (dMRI) data, leading to biased diffusion model fits and inaccurate signal averaging. Here, we introduce a total-variation-based algorithm to eliminate shot-to-shot phase variations of complex-valued diffusion data with the intention to extract real-valued dMRI datasets. The obtained real-valued diffusion data are no longer superimposed by a noise floor but instead by a zero-mean Gaussian noise distribution, yielding dMRI data without signal bias. We acquired high-resolution dMRI data with strong diffusion weighting and, thus, low signal-to-noise ratio. Both the extracted real-valued and traditional magnitude data were compared regarding signal averaging, diffusion model fitting and accuracy in resolving crossing fibers. Our results clearly indicate that real-valued diffusion data enables idealized conditions for signal averaging. Furthermore, the proposed method enables unbiased use of widely employed linear least squares estimators for model fitting and demonstrates an increased sensitivity to detect secondary fiber directions with reduced angular error. The use of phase-corrected, real-valued data for dMRI will therefore help to clear the way for more detailed and accurate studies of white matter microstructure and structural connectivity on a fine scale.

  17. The Relative Effectiveness of Signaling Systems: Relying on External Items Reduces Signaling Accuracy while Leks Increase Accuracy

    PubMed Central

    Leighton, Gavin M.

    2014-01-01

    Multiple evolutionary phenomena require individual animals to assess conspecifics based on behaviors, morphology, or both. Both behavior and morphology can provide information about individuals and are often used as signals to convey information about quality, motivation, or energetic output. In certain cases, conspecific receivers of this information must rank these signaling individuals based on specific traits. The efficacy of information transfer associated within a signal is likely related to the type of trait used to signal, though few studies have investigated the relative effectiveness of contrasting signaling systems. I present a set of models that represent a large portion of signaling systems and compare them in terms of the ability of receivers to rank signalers accurately. Receivers more accurately assess signalers if the signalers use traits that do not require non-food resources; similarly, receivers more accurately ranked signalers if all the signalers could be observed simultaneously, similar to leks. Surprisingly, I also found that receivers are only slightly better at ranking signaler effort if the effort results in a cumulative structure. This series of findings suggests that receivers may attend to specific traits because the traits provide more information relative to others; and similarly, these results may explain the preponderance of morphological and behavioral display signals. PMID:24626221

  18. Enhanced monocyte migration to CXCR3 and CCR5 chemokines in COPD.

    PubMed

    Costa, Claudia; Traves, Suzanne L; Tudhope, Susan J; Fenwick, Peter S; Belchamber, Kylie B R; Russell, Richard E K; Barnes, Peter J; Donnelly, Louise E

    2016-04-01

    Chronic obstructive pulmonary disease (COPD) patients exhibit chronic inflammation, both in the lung parenchyma and the airways, which is characterised by an increased infiltration of macrophages and T-lymphocytes, particularly CD8+ cells. Both cell types can express chemokine (C-X-C motif) receptor (CXCR)3 and C-C chemokine receptor 5 and the relevant chemokines for these receptors are elevated in COPD. The aim of this study was to compare chemotactic responses of lymphocytes and monocytes of nonsmokers, smokers and COPD patients towards CXCR3 ligands and chemokine (C-C motif) ligand (CCL)5. Migration of peripheral blood mononuclear cells, monocytes and lymphocytes from nonsmokers, smokers and COPD patients toward CXCR3 chemokines and CCL5 was analysed using chemotaxis assays. There was increased migration of peripheral blood mononuclear cells from COPD patients towards all chemokines studied when compared with nonsmokers and smokers. Both lymphocytes and monocytes contributed to this enhanced response, which was not explained by increased receptor expression. However, isolated lymphocytes failed to migrate and isolated monocytes from COPD patients lost their enhanced migratory capacity. Both monocytes and lymphocytes cooperate to enhance migration towards CXCR3 chemokines and CCL5. This may contribute to increased numbers of macrophages and T-cells in the lungs of COPD patients, and inhibition of recruitment using selective antagonists might be a treatment to reduce the inflammatory response in COPD.

  19. The chemokine receptor CXCR7 is highly expressed in human glioma cells and mediates antiapoptotic effects.

    PubMed

    Hattermann, Kirsten; Held-Feindt, Janka; Lucius, Ralph; Müerköster, Susanne Sebens; Penfold, Mark E T; Schall, Thomas J; Mentlein, Rolf

    2010-04-15

    The chemokine CXCL12/stromal cell-derived factor-1 and its receptor CXCR4 play a major role in tumor invasion, proliferation, and metastasis. Recently, CXCR7 was identified as a novel, alternate receptor for CXCL12 and CXCL11/I-TAC. Because both chemokines are expressed abundantly in human astrocytomas and glioblastomas, we investigated the occurrence and function of both receptors in astroglial tumors. In situ, CXCR7 is highly expressed on tumor endothelial, microglial, and glioma cells whereas CXCR4 has a much more restricted localization; CXCL12 is often colocalized with CXCR7. CXCR7 transcription in tumor homogenates increased with malignancy. In vitro, CXCR7 was highly expressed in all glioma cell lines investigated whereas CXCR4 was only scarcely transcribed on one of eight lines. In contrast, a tumor stem-like cell line preferentially expressed CXCR4 which diminished upon differentiation, whereas CXCR7 increased drastically. Stimulation of CXCR7-positive glioma cells (CXCR4- and CXCR3-negative) by CXCL12 induced transient phosphorylation of extracellular signal-regulated kinases Erk1/2, indicating that the receptor is functionally active. The phosphoinositide-specific phospholipase C inhibitor U73122 effectively inhibited Erk activation and suggests that the mitogen-activated protein kinase pathway is activated indirectly. Whereas proliferation and migration were little influenced, chemokine stimulation prevented camptothecin- and temozolomide-induced apoptosis. The selective CXCR7 antagonist CCX733 reduced the antiapoptotic effects of CXCL12 as shown by nuclear (Nicoletti) staining, caspase-3/7 activity assays, and cleavage of poly(ADP-ribose) polymerase-1. Thus, CXCR7 is a functional receptor for CXCL12 in astrocytomas/glioblastomas and mediates resistance to drug-induced apoptosis. Whereas CXCR7 is found on "differentiated" glioma cells, the alternate receptor CXCR4 is also localized on glioma stem-like cells.

  20. Inhibition of apoptosis signal-regulating kinase 1 enhances endochondral bone formation by increasing chondrocyte survival

    PubMed Central

    Eaton, G J; Zhang, Q-S; Diallo, C; Matsuzawa, A; Ichijo, H; Steinbeck, M J; Freeman, T A

    2014-01-01

    Endochondral ossification is the result of chondrocyte differentiation, hypertrophy, death and replacement by bone. The careful timing and progression of this process is important for normal skeletal bone growth and development, as well as fracture repair. Apoptosis Signal-Regulating Kinase 1 (ASK1) is a mitogen-activated protein kinase (MAPK), which is activated by reactive oxygen species and other cellular stress events. Activation of ASK1 initiates a signaling cascade known to regulate diverse cellular events including cytokine and growth factor signaling, cell cycle regulation, cellular differentiation, hypertrophy, survival and apoptosis. ASK1 is highly expressed in hypertrophic chondrocytes, but the role of ASK1 in skeletal tissues has not been investigated. Herein, we report that ASK1 knockout (KO) mice display alterations in normal growth plate morphology, which include a shorter proliferative zone and a lengthened hypertrophic zone. These changes in growth plate dynamics result in accelerated long bone mineralization and an increased formation of trabecular bone, which can be attributed to an increased resistance of terminally differentiated chondrocytes to undergo cell death. Interestingly, under normal cell culture conditions, mouse embryonic fibroblasts (MEFs) derived from ASK1 KO mice show no differences in either MAPK signaling or osteogenic or chondrogenic differentiation when compared with wild-type (WT) MEFs. However, when cultured with stress activators, H2O2 or staurosporine, the KO cells show enhanced survival, an associated decrease in the activation of proteins involved in death signaling pathways and a reduction in markers of terminal differentiation. Furthermore, in both WT mice treated with the ASK1 inhibitor, NQDI-1, and ASK1 KO mice endochondral bone formation was increased in an ectopic ossification model. These findings highlight a previously unrealized role for ASK1 in regulating endochondral bone formation. Inhibition of ASK1 has

  1. IL-6 signaling blockade increases inflammation but does not affect muscle function in the mdx mouse

    PubMed Central

    2012-01-01

    Background IL-6 is a pleiotropic cytokine that modulates inflammatory responses and plays critical roles in muscle maintenance and remodeling. In the mouse model (mdx) of Duchenne Muscular Dystrophy, IL-6 and muscle inflammation are elevated, which is believed to contribute to the chronic inflammation and failure of muscle regeneration in DMD. The purpose of the current study was to examine the effect of blocking IL-6 signaling on the muscle phenotype including muscle weakness and pathology in the mdx mouse. Methods A monoclonal antibody against the IL-6 receptor (IL-6r mAb) that blocks local and systemic IL-6 signaling was administered to mdx and BL-10 mice for 5 weeks and muscle function, histology, and inflammation were examined. Results IL-6r mAb treatment increased mdx muscle inflammation including total inflammation score and ICAM-1 positive lumens in muscles. There was no significant improvement in muscle strength nor muscle pathology due to IL-6r mAb treatment in mdx mice. Conclusions These results showed that instead of reducing inflammation, IL-6 signaling blockade for 5 weeks caused an increase in muscle inflammation, with no significant change in indices related to muscle regeneration and muscle function. The results suggest a potential anti-inflammatory instead of the original hypothesized pro-inflammatory role of IL-6 signaling in the mdx mice. PMID:22716658

  2. Scopolamine rapidly increases mTORC1 signaling, synaptogenesis, and antidepressant behavioral responses

    PubMed Central

    Voleti, Bhavya; Navarria, Andrea; Liu, Rong-Jian; Banasr, Mounira; Li, Nanxin; Terwilliger, Rose; Sanacora, Gerard; Eid, Tore; Aghajanian, George; Duman, Ronald S.

    2013-01-01

    Background Clinical studies report that scopolamine, an acetylcholine muscarinic receptor antagonist, produces rapid antidepressant effects in depressed patients, but the mechanisms underlying the therapeutic response have not been determined. The present study examines the role of the mammalian target of rapamycin complex 1 (mTORC1) and synaptogenesis, which have been implicated in the rapid actions of NMDA receptor antagonists. Methods The influence of scopolamine on mTORC1 signaling was determined by analysis of the phosphorylated and activated forms of mTORC1 signaling proteins in the prefrontal cortex (PFC). The numbers and function of spine synapses were analyzed by whole cell patch clamp recording and 2-photon image analysis of PFC neurons. The actions of scopolamine were examined in the forced swim test in the absence or presence of selective mTORC1 and AMPA receptor inhibitors. Results The results demonstrate that a single, low dose of scopolamine rapidly increases mTORC1 signaling and the number and function of spine synapses in layer V pyramidal neurons in the PFC. Scopolamine administration also produces an antidepressant response in the forced swim test that is blocked by pretreatment with the mTORC1 inhibitor or by a glutamate AMPA receptor antagonist. Conclusions Taken together, the results demonstrate that the antidepressant actions of scopolamine require mTORC1 signaling and are associated with increased glutamate transmission, and synaptogenesis, similar to NMDA receptor antagonists. These findings provide novel targets for safer and more efficacious rapid acting antidepressant agents. PMID:23751205

  3. Cyclic stretch of Embryonic Cardiomyocytes Increases Proliferation, Growth, and Expression While Repressing Tgf-β Signaling

    PubMed Central

    Banerjee, Indroneal; Carrion, Katrina; Serrano, Ricardo; Dyo, Jeffrey; Sasik, Roman; Lund, Sean; Willems, Erik; Aceves, Seema; Meili, Rudolph; Mercola, Mark; Chen, Ju; Zambon, Alexander; Hardiman, Gary; Doherty, Taylor A; Lange, Stephan; del Álamo, Juan C.; Nigam, Vishal

    2014-01-01

    Perturbed biomechanical stimuli are thought to be critical for the pathogenesis of a number of congenital heart defects, including Hypoplastic Left Heart Syndrome (HLHS). While embryonic cardiomyocytes experience biomechanical stretch every heart beat, their molecular responses to biomechanical stimuli during heart development are poorly understood. We hypothesized that biomechanical stimuli activate specific signaling pathways that impact proliferation, gene expression and myocyte contraction. The objective of this study was to expose embryonic mouse cardiomyocytes (EMCM) to cyclic stretch and examine key molecular and phenotypic responses. Analysis of RNA-Sequencing data demonstrated that gene ontology groups associated with myofibril and cardiac development were significantly modulated. Stretch increased EMCM proliferation, size, cardiac gene expression, and myofibril protein levels. Stretch also repressed several components belonging to the Transforming Growth Factor-β (Tgf-β) signaling pathway. EMCMs undergoing cyclic stretch had decreased Tgf-β expression, protein levels, and signaling. Furthermore, treatment of EMCMs with a Tgf-β inhibitor resulted in increased EMCM size. Functionally, Tgf-β signaling repressed EMCM proliferation and contractile function, as assayed via dynamic monolayer force microscopy (DMFM). Taken together, these data support the hypothesis that biomechanical stimuli play a vital role in normal cardiac development and for cardiac pathology, including HLHS. PMID:25446186

  4. The Chemokine Receptor CCR1 Is Constitutively Active, Which Leads to G Protein-independent, β-Arrestin-mediated Internalization*

    PubMed Central

    Gilliland, C. Taylor; Salanga, Catherina L.; Kawamura, Tetsuya; Trejo, JoAnn; Handel, Tracy M.

    2013-01-01

    Activation of G protein-coupled receptors by their associated ligands has been extensively studied, and increasing structural information about the molecular mechanisms underlying ligand-dependent receptor activation is beginning to emerge with the recent expansion in GPCR crystal structures. However, some GPCRs are also able to adopt active conformations in the absence of agonist binding that result in the initiation of signal transduction and receptor down-modulation. In this report, we show that the CC-type chemokine receptor 1 (CCR1) exhibits significant constitutive activity leading to a variety of cellular responses. CCR1 expression is sufficient to induce inhibition of cAMP formation, increased F-actin content, and basal migration of human and murine leukocytes. The constitutive activity leads to basal phosphorylation of the receptor, recruitment of β-arrestin-2, and subsequent receptor internalization. CCR1 concurrently engages Gαi and β-arrestin-2 in a multiprotein complex, which may be accommodated by homo-oligomerization or receptor clustering. The data suggest the presence of two functional states for CCR1; whereas receptor coupled to Gαi functions as a canonical GPCR, albeit with high constitutive activity, the CCR1·β-arrestin-2 complex is required for G protein-independent constitutive receptor internalization. The pertussis toxin-insensitive uptake of chemokine by the receptor suggests that the CCR1·β-arrestin-2 complex may be related to a potential scavenging function of the receptor, which may be important for maintenance of chemokine gradients and receptor responsiveness in complex fields of chemokines during inflammation. PMID:24056371

  5. Chemokines as Therapeutic Targets to Improve Healing Efficiency of Chronic Wounds

    PubMed Central

    Satish, Latha

    2015-01-01

    Significance: Impaired wound healing leading to chronic wounds is an important clinical problem that needs immediate attention to develop new effective therapies. Members of the chemokine family seem to be attractive and amenable to stimulate the healing process in chronic wounds. Targeting specific chemokines and/or their receptors has the potential to modify chronic inflammation to acute inflammation, which will hasten the healing process. Recent Advances: Over the years, expression levels of various chemokines and their receptors have been identified as key players in the inflammatory phase of wound healing. In addition, they contribute to regulating other phases of wound healing making them key targets for novel therapies. Understanding the signaling pathways of these chemokines will provide valuable clues for modulating their function to enhance the wound healing process. Critical Issues: Inflammation, an important first-stage process in wound healing, is dysregulated in chronic wounds; emerging studies show that chemokines play a crucial role in regulating inflammation. The knowledge gained so far is still limited in understanding the enormous complexity of the chemokine network during inflammation not just in chronic wounds but also in acute (normal) wounds. A much better understanding of the individual chemokines will pave the way for better targets and therapies to improve the healing efficiency of chronic wounds. Future Directions: Effective understanding of the interaction of chemokines and their receptors during chronic wound healing would facilitate the design of novel therapeutic drugs. Development of chemokine-based drugs targeting specific inflammatory cells will be invaluable in the treatment of chronic wounds, in which inflammation plays a major role. PMID:26543679

  6. Novel chemokine-like activities of histones in tumor metastasis

    PubMed Central

    Chen, Ruochan; Xie, Yangchun; Zhong, Xiao; Fu, Yongmin; Huang, Yan; Zhen, Yixiang; Pan, Pinhua; Wang, Haichao; Bartlett, David L.; Billiar, Timothy R.; Lotze, Michael T.; Zeh, Herbert J.; Fan, Xue-Gong; Tang, Daolin; Kang, Rui

    2016-01-01

    Histones are intracellular nucleosomal components and extracellular damage-associated molecular pattern molecules that modulate chromatin remodeling, as well as the immune response. However, their extracellular roles in cell migration and invasion remain undefined. Here, we demonstrate that histones are novel regulators of tumor metastasis with chemokine-like activities. Indeed, exogenous histones promote both hepatocellular carcinoma (HCC) cell migration and invasion through toll-like receptor (TLR)4, but not TLR2 or the receptor for advanced glycosylation end product. TLR4-mediated activation of nuclear factor-κB (NF-κB) by extracellular signal-regulated kinase (ERK) is required for histone-induced chemokine (e.g., C-C motif ligand 9/10) production. Pharmacological and genetic inhibition of TLR4-ERK-NF-κB signaling impairs histone-induced chemokine production and HCC cell migration. Additionally, TLR4 depletion (by using TLR4−/− mice and TLR4-shRNA) or inhibition of histone release/activity (by administration of heparin and H3 neutralizing antibody) attenuates lung metastasis of HCC cells injected via the tail vein of mice. Thus, histones promote tumor metastasis of HCC cells through the TLR4-NF-κB pathway and represent novel targets for treating patients with HCC. PMID:27623211

  7. CCL2-induced chemokine cascade promotes breast cancer metastasis by enhancing retention of metastasis-associated macrophages

    PubMed Central

    Kitamura, Takanori; Qian, Bin-Zhi; Soong, Daniel; Cassetta, Luca; Noy, Roy; Sugano, Gaël; Kato, Yu; Li, Jiufeng

    2015-01-01

    Pulmonary metastasis of breast cancer cells is promoted by a distinct population of macrophages, metastasis-associated macrophages (MAMs), which originate from inflammatory monocytes (IMs) recruited by the CC-chemokine ligand 2 (CCL2). We demonstrate here that, through activation of the CCL2 receptor CCR2, the recruited MAMs secrete another chemokine ligand CCL3. Genetic deletion of CCL3 or its receptor CCR1 in macrophages reduces the number of lung metastasis foci, as well as the number of MAMs accumulated in tumor-challenged lung in mice. Adoptive transfer of WT IMs increases the reduced number of lung metastasis foci in Ccl3 deficient mice. Mechanistically, Ccr1 deficiency prevents MAM retention in the lung by reducing MAM–cancer cell interactions. These findings collectively indicate that the CCL2-triggered chemokine cascade in macrophages promotes metastatic seeding of breast cancer cells thereby amplifying the pathology already extant in the system. These data suggest that inhibition of CCR1, the distal part of this signaling relay, may have a therapeutic impact in metastatic disease with lower toxicity than blocking upstream targets. PMID:26056232

  8. CCL2-induced chemokine cascade promotes breast cancer metastasis by enhancing retention of metastasis-associated macrophages.

    PubMed

    Kitamura, Takanori; Qian, Bin-Zhi; Soong, Daniel; Cassetta, Luca; Noy, Roy; Sugano, Gaël; Kato, Yu; Li, Jiufeng; Pollard, Jeffrey W

    2015-06-29

    Pulmonary metastasis of breast cancer cells is promoted by a distinct population of macrophages, metastasis-associated macrophages (MAMs), which originate from inflammatory monocytes (IMs) recruited by the CC-chemokine ligand 2 (CCL2). We demonstrate here that, through activation of the CCL2 receptor CCR2, the recruited MAMs secrete another chemokine ligand CCL3. Genetic deletion of CCL3 or its receptor CCR1 in macrophages reduces the number of lung metastasis foci, as well as the number of MAMs accumulated in tumor-challenged lung in mice. Adoptive transfer of WT IMs increases the reduced number of lung metastasis foci in Ccl3 deficient mice. Mechanistically, Ccr1 deficiency prevents MAM retention in the lung by reducing MAM-cancer cell interactions. These findings collectively indicate that the CCL2-triggered chemokine cascade in macrophages promotes metastatic seeding of breast cancer cells thereby amplifying the pathology already extant in the system. These data suggest that inhibition of CCR1, the distal part of this signaling relay, may have a therapeutic impact in metastatic disease with lower toxicity than blocking upstream targets.

  9. Regulation of inflammatory chemokine receptors on blood T cells associated to the circulating versus liver chemokines in dengue fever.

    PubMed

    de-Oliveira-Pinto, Luzia Maria; Marinho, Cíntia Ferreira; Povoa, Tiago Fajardo; de Azeredo, Elzinandes Leal; de Souza, Luiza Assed; Barbosa, Luiza Damian Ribeiro; Motta-Castro, Ana Rita C; Alves, Ada M B; Ávila, Carlos André Lins; de Souza, Luiz José; da Cunha, Rivaldo Venâncio; Damasco, Paulo Vieira; Paes, Marciano Viana; Kubelka, Claire Fernandes

    2012-01-01

    Little is known about the role of chemokines/chemokines receptors on T cells in natural DENV infection. Patients from DENV-2 and -3- outbreaks were studied prospectively during the acute or convalescent phases. Expression of chemokine receptor and activation markers on lymphocyte subpopulations were determined by flow cytometry analysis, plasma chemokine ligands concentrations were measured by ELISA and quantification of CCL5/RANTES(+) cells in liver tissues from fatal dengue cases was performed by immunochemistry. In the acute DENV-infection, T-helper/T-cytotoxic type-1 cell (Th1/Tc1)-related CCR5 is significantly higher expressed on both CD4 and CD8 T cells. The Th1-related CXCR3 is up-regulated among CD4 T cells and Tc2-related CCR4 is up-regulated among CD8 T cells. In the convalescent phase, all chemokine receptor or chemokine ligand expression tends to reestablish control healthy levels. Increased CCL2/MCP-1 and CCL4/MIP-1β but decreased CCL5/RANTES levels were observed in DENV-patients during acute infection. Moreover, we showed an increased CD107a expression on CCR5 or CXCR3-expressing T cells and higher expression of CD29, CD44(HIGH) and CD127(LOW) markers on CCR4-expressing CD8 T cells in DENV-patients when compared to controls. Finally, liver from dengue fatal patients showed increased number of cells expressing CCL5/RANTES in three out of four cases compared to three death from a non-dengue patient. In conclusion, both Th1-related CCR5 and CXCR3 among CD4 T cells have a potential ability to exert cytotoxicity function. Moreover, Tc1-related CCR5 and Tc2-related CCR4 among CD8 T cells have a potential ability to exert effector function and migration based on cell markers evaluated. The CCR5 expression would be promoting an enhanced T cell recruitment into liver, a hypothesis that is corroborated by the CCL5/RANTES increase detected in hepatic tissue from dengue fatal cases. The balance between protective and pathogenic immune response mediated by

  10. Increasing signal-to-noise ratio of marine seismic data: A case study from offshore Korea

    NASA Astrophysics Data System (ADS)

    Kim, Taeyoun; Jang, Seonghyung

    2016-11-01

    Subsurface imaging is difficult without removing the multiples intrinsic to most marine seismic data. Choosing the right multiple suppression method when working with marine data depends on the type of multiples and sometimes involves trial and error. A major amount of multiple energy in seismic data is related to the large reflectivity of the surface. Surface-related multiple elimination (SRME) is effective for suppressing free-surface-related multiples. Although SRME has some limitations, it is widely used because it requires no assumptions about the subsurface velocities, positions, and reflection coefficients of the reflector causing the multiples. The common reflector surface (CRS) stacking technique uses CRS reflectors rather than common mid-point (CMP) reflectors. It stacks more traces than conventional stacking methods and increases the signal-to-noise ratio. The purpose of this study is to address a process issue for multiple suppression with SRME and Radon filtering, and to increase the signal-to-noise ratio by using CRS stacking on seismic data from the eastern continental margin of Korea. To remove free surface multiples, SRME and Radon filtering are applied to attenuate the interbed multiples. Results obtained using synthetic data and field data show that the combination of SRME and Radon filtering is effective for suppressing free-surface multiples and peg-leg multiples. Applying CRS stacking to seismic data in which multiples have been eliminated increases the signal-to-noise ratio for the area examined, which is being considered for carbon dioxide capture and storage.

  11. Peptide YY signaling in the lateral parabrachial nucleus increases food intake through the Y1 receptor

    PubMed Central

    Golub, Danielle; Hayes, Matthew R.; Grill, Harvey J.

    2015-01-01

    Although central PYY delivery potently increases food intake, the sites of action and mechanisms mediating these hyperphagic effects are not fully understood. The present studies investigate the contribution of lateral parabrachial nucleus (lPBN) PYY-Y receptor signaling to food intake control, as lPBN neurons express Y receptors and receive PYY fibers and are known to integrate circulating and visceral sensory signals to regulate energy balance. Immunohistochemical results identified a subpopulation of gigantocellular reticular nucleus PYY-producing neurons that project monosynaptically to the lPBN, providing an endogenous source of PYY to the lPBN. lPBN microinjection of PYY-(1–36) or PYY-(3–36) markedly increased food intake by increasing meal size. To determine which receptors mediate these behavioral results, we first performed quantitative real-time PCR to examine the relative levels of Y receptor expression in lPBN tissue. Gene expression analyses revealed that, while Y1, Y2, and Y5 receptors are each expressed in lPBN tissue, Y1 receptor mRNA is expressed at fivefold higher levels than the others. Furthermore, behavioral/pharmacological results demonstrated that the hyperphagic effects of PYY-(3–36) were eliminated by lPBN pretreatment with a selective Y1 receptor antagonist. Together, these results highlight the lPBN as a novel site of action for the intake-stimulatory effects of central PYY-Y1 receptor signaling. PMID:26330345

  12. Phosphodiesterase DosP increases persistence by reducing cAMP which reduces the signal indole.

    PubMed

    Kwan, Brian W; Osbourne, Devon O; Hu, Ying; Benedik, Michael J; Wood, Thomas K

    2015-03-01

    Persisters are bacteria that are highly tolerant to antibiotics due to their dormant state and are of clinical significance owing to their role in infections. Given that the population of persisters increases in biofilms and that cyclic diguanylate (c-di-GMP) is an intracellular signal that increases biofilm formation, we sought to determine whether c-di-GMP has a role in bacterial persistence. By examining the effect of 30 genes from Escherichia coli, including diguanylate cyclases that synthesize c-di-GMP and phosphodiesterases that breakdown c-di-GMP, we determined that DosP (direct oxygen sensing phosphodiesterase) increases persistence by over a thousand fold. Using both transcriptomic and proteomic approaches, we determined that DosP increases persistence by decreasing tryptophanase activity and thus indole. Corroborating this effect, addition of indole reduced persistence. Despite the role of DosP as a c-di-GMP phosphodiesterase, the decrease in tryptophanase activity was found to be a result of cyclic adenosine monophosphate (cAMP) phosphodiesterase activity. Corroborating this result, the reduction of cAMP via CpdA, a cAMP-specific phosphodiesterase, increased persistence and reduced indole levels similarly to DosP. Therefore, phosphodiesterase DosP increases persistence by reducing the interkingdom signal indole via reduction of the global regulator cAMP.

  13. Tyrosine sulfation influences the chemokine binding selectivity of peptides derived from chemokine receptor CCR3.

    PubMed

    Zhu, John Z; Millard, Christopher J; Ludeman, Justin P; Simpson, Levi S; Clayton, Daniel J; Payne, Richard J; Widlanski, Theodore S; Stone, Martin J

    2011-03-08

    The interactions of chemokines with their G protein-coupled receptors play critical roles in the control of leukocyte trafficking in normal homeostasis and in inflammatory responses. Tyrosine sulfation is a common post-translational modification in the amino-terminal regions of chemokine receptors. However, tyrosine sulfation of chemokine receptors is commonly incomplete or heterogeneous. To investigate the possibility that differential sulfation of two adjacent tyrosine residues could bias the responses of chemokine receptor CCR3 to different chemokines, we have studied the binding of three chemokines (eotaxin-1/CCL11, eotaxin-2/CCL24, and eotaxin-3/CCL26) to an N-terminal CCR3-derived peptide in each of its four possible sulfation states. Whereas the nonsulfated peptide binds to the three chemokines with approximately equal affinity, sulfation of Tyr-16 gives rise to 9-16-fold selectivity for eotaxin-1 over the other two chemokines. Subsequent sulfation of Tyr-17 contributes additively to the affinity for eotaxin-1 and eotaxin-2 but cooperatively to the affinity for eotaxin-3. The doubly sulfated peptide selectively binds to both eotaxin-1 and eotaxin-3 approximately 10-fold more tightly than to eotaxin-2. Nuclear magnetic resonance chemical shift mapping indicates that these variations in affinity probably result from only subtle differences in the chemokine surfaces interacting with these receptor peptides. These data support the proposal that variations in sulfation states or levels may regulate the responsiveness of chemokine receptors to their cognate chemokines.

  14. Leptin signaling in the nucleus tractus solitarii increases sympathetic nerve activity to the kidney.

    PubMed

    Mark, Allyn L; Agassandian, Khristofor; Morgan, Donald A; Liu, Xuebo; Cassell, Martin D; Rahmouni, Kamal

    2009-02-01

    The hypothalamic arcuate nucleus was initially regarded as the principal site of leptin action, but there is increasing evidence for functional leptin receptors in extrahypothalamic sites, including the nucleus tractus solitarii (NTS). We demonstrated previously that arcuate injection of leptin increases sympathetic nerve activity (SNA) to brown adipose tissue and kidney. In this study, we tested the hypothesis that leptin signaling in the NTS affects sympathetic neural outflow. Using a stereotaxic device in anesthetized rats, we microinjected leptin (0.25 to 1.00 microg) or saline into the NTS while recording SNA to kidney and brown adipose tissue. Microinjection of leptin into the commissural and medial subnuclei of the caudal NTS at the level of the area postrema in Sprague-Dawley rats produced a dose-related increase in renal SNA (+112+/-15% with leptin 1 microg; n=7; P<0.001) but did not increase SNA to brown adipose tissue (-15+/-12%; P value not significant). This effect depended on intact functional leptin receptors, because it was not observed in Zucker obese rats that have a missense mutation in the leptin receptor. Rostral NTS injection of leptin failed to increase SNA, indicating that leptin signaling in the NTS is probably confined to the caudal NTS at the level of the area postrema. In summary, this study demonstrates that leptin signaling in the caudal NTS increases SNA to the kidney but not to the brown adipose tissue. The study strengthens the concept of a distributed brain network of leptin action and demonstrates that these distributed brain sites can mediate contrasting sympathetic responses to leptin.

  15. Light-load resistance exercise increases muscle protein synthesis and hypertrophy signaling in elderly men.

    PubMed

    Agergaard, Jakob; Bülow, Jacob; Jensen, Jacob K; Reitelseder, Søren; Drummond, Micah J; Schjerling, Peter; Scheike, Thomas; Serena, Anja; Holm, Lars

    2017-04-01

    The present study investigated whether well-tolerated light-load resistance exercise (LL-RE) affects skeletal muscle fractional synthetic rate (FSR) and anabolic intracellular signaling as a way to counteract age-related loss of muscle mass. Untrained healthy elderly (>65-yr-old) men were subjected to 13 h of supine rest. After 2.5 h of rest, unilateral LL-RE, consisting of leg extensions (10 sets, 36 repetitions) at 16% of 1 repetition maximum (RM), was conducted. Subsequently, the subjects were randomized to oral intake of 4 g of whey protein per hour (PULSE, n = 10), 28 g of whey protein at 0 h and 12 g of whey protein at 7 h postexercise (BOLUS, n = 10), or 4 g of maltodextrin per hour (placebo, n = 10). Quadriceps muscle biopsies were taken at 0, 3, 7, and 10 h postexercise from the resting and the exercised leg of each subject. Myofibrillar FSR and activity of select targets from the mechanistic target of rapamycin complex 1-signaling cascade were analyzed from the biopsies. LL-RE increased myofibrillar FSR compared with the resting leg throughout the 10-h postexercise period. Phosphorylated (T308) AKT expression increased in the exercised leg immediately after exercise. This increase persisted in the placebo group only. Levels of phosphorylated (T37/46) eukaryotic translation initiation factor 4E-binding protein 1 increased throughout the postexercise period in the exercised leg in the placebo and BOLUS groups and peaked at 7 h. In all three groups, phosphorylated (T56) eukaryotic elongation factor 2 decreased in response to LL-RE. We conclude that resistance exercise at only 16% of 1 RM increased myofibrillar FSR, irrespective of nutrient type and feeding pattern, which indicates an anabolic effect of LL-RE in elderly individuals. This finding was supported by increased signaling for translation initiation and translation elongation in response to LL-RE.

  16. Increasing signal amplitude in fiber Bragg grating detection of Lamb waves using remote bonding.

    PubMed

    Wee, Junghyun; Wells, Brian; Hackney, Drew; Bradford, Philip; Peters, Kara

    2016-07-20

    Networks of fiber Bragg grating (FBG) sensors can serve as structural health monitoring systems for large-scale structures based on the collection of ultrasonic waves. The demodulation of structural Lamb waves using FBG sensors requires a high signal-to-noise ratio because the Lamb waves are of low amplitudes. This paper compares the signal transfer amplitudes between two adhesive mounting configurations for an FBG to detect Lamb waves propagating in an aluminum plate: a directly bonded FBG and a remotely bonded FBG. In the directly bonded FBG case, the Lamb waves create in-plane and out-of-plane displacements, which are transferred through the adhesive bond and detected by the FBG sensor. In the remotely bonded FBG case, the Lamb waves are converted into longitudinal and flexural traveling waves in the optical fiber at the adhesive bond, which propagate through the optical fiber and are detected by the FBG sensor. A theoretical prediction of overall signal attenuation also is performed, which is the combination of material attenuation in the plate and optical fiber and attenuation due to wave spreading in the plate. The experimental results demonstrate that remote bonding of the FBG significantly increases the signal amplitude measured by the FBG.

  17. Floral visual signal increases reproductive success in a sexually deceptive orchid.

    PubMed

    Rakosy, Demetra; Streinzer, Martin; Paulus, Hannes F; Spaethe, Johannes

    2012-12-01

    Sexually deceptive orchids mimic signals emitted by female insects in order to attract mate-searching males. Specific attraction of the targeted pollinator is achieved by sex pheromone mimicry, which constitutes the major attraction channel. In close vicinity of the flower, visual signals may enhance attraction, as was shown recently in the sexually deceptive orchid Ophrys heldreichii. Here, we conducted an in situ manipulation experiment in two populations of O. heldreichii on Crete to investigate whether the presence/absence of the conspicuous pink perianth affects reproductive success in two natural orchid populations. We estimated reproductive success of three treatment groups (with intact, removed and artificial perianth) throughout the flowering period as pollinaria removal (male reproductive success) and massulae deposition (female reproductive success). Reproductive success was significantly increased by the presence of a strong visual signal-the conspicuous perianth-in one study population, however, not in the second, most likely due to the low pollinator abundance in the latter population. This study provides further evidence that the coloured perianth in O. heldreichii is adaptive and thus adds to the olfactory signal to maximise pollinator attraction and reproductive success.

  18. Chemokines Associated with Pathologic Responses to Orthopedic Implant Debris

    PubMed Central

    Hallab, Nadim J.; Jacobs, Joshua J.

    2017-01-01

    Despite the success in returning people to health saving mobility and high quality of life, the over 1 million total joint replacements implanted in the US each year are expected to eventually fail after approximately 15–25 years of use, due to slow progressive subtle inflammation to implant debris compromising the bone implant interface. This local inflammatory pseudo disease state is primarily caused by implant debris interaction with innate immune cells, i.e., macrophages. This implant debris can also activate an adaptive immune reaction giving rise to the concept of implant-related metal sensitivity. However, a consensus of studies agree the dominant form of this response is due to innate reactivity by macrophages to implant debris danger signaling (danger-associated molecular pattern) eliciting cytokine-based and chemokine inflammatory responses. This review covers implant debris-induced release of the cytokines and chemokines due to activation of the innate (and the adaptive) immune system and how this leads to subsequent implant failure through loosening and osteolysis, i.e., what is known of central chemokines (e.g., IL-8, monocyte chemotactic protein-1, MIP-1, CCL9, CCL10, CCL17, and CCL22) associated with implant debris reactivity as related to the innate immune system activation/cytokine expression, e.g., danger signaling (e.g., IL-1β, IL-18, IL-33, etc.), toll-like receptor activation (e.g., IL-6, tumor necrosis factor α, etc.), bone catabolism (e.g., TRAP5b), and hypoxia responses (HIF-1α). More study is needed, however, to fully understand these interactions to effectively counter cytokine- and chemokine-based orthopedic implant-related inflammation. PMID:28154552

  19. Effects of cobalt chloride on nitric oxide and cytokines/chemokines production in microglia.

    PubMed

    Mou, Yan Hua; Yang, Jing Yu; Cui, Nan; Wang, Ji Ming; Hou, Yue; Song, Shuang; Wu, Chun Fu

    2012-05-01

    The involvement of microglial activation in metal neurotoxicity is becoming increasingly recognized. Some metal ions, such as zinc (II) and manganese (II), have been recently reported as microglial activators to induce the release of inflammatory mediators including cytokines, chemokines and nitric oxide (NO) which are involved in the pathogenesis of neurological diseases. Cobalt is essential for human life. However, excessive cobalt is cytotoxic and neurotoxic. In the present study, we determined cobalt-induced production of NO and cytokines/chemokines in N9 cells, a murine microglial cell line. High levels of cobalt significantly up-regulated iNOS mRNA and protein expression, which resulted in the release of NO. Cobalt induced the production of tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) in a concentration- and time-dependent manner in both N9 cells and primary mouse microglia and increased lipopolysaccharides (LPS)-induced cytokine production. Further study showed that cobalt induced cytokine production by a mechanism involving both nuclear factor kappa B (NF-κB) and p38 mitogen-activated protein kinase (MAPK) signaling pathways. The involvement of reactive oxygen species (ROS) in microglial activation was also confirmed. These findings suggested that cobalt neurotoxicity should be attributed not only directly to neuronal damage but also indirectly to microglial activation which might potentiate neuronal injury via elevation of proinflammatory mediator levels.

  20. HMGB1/TLR Receptor Danger Signaling Increases Brain Neuroimmune Activation in Alcohol Dependence

    PubMed Central

    Crews, Fulton T.; Qin, Liya; Sheedy, Donna; Vetreno, Ryan P.; Zou, Jian

    2012-01-01

    Background Innate immune gene expression is regulated in part through high mobility group box 1(HMGB1), an endogenous proinflammatory cytokine, that activates multiple members of the interleukin-1/Toll-like receptor (IL-1/TLR) family associated with danger signaling. We investigated expression of HMGB1, TLR2, TLR3 and TLR4 in chronic ethanol treated mouse brain, post-mortem human alcoholic brain, and rat brain slice culture to test the hypothesis that neuroimmune activation in alcoholic brain involves ethanol activation of HMGB1/TLR danger signaling. Methods Protein levels were assessed using Western blot, ELISA, immunohistochemical immunoreactivity (+IR), and mRNA levels were measured by real time PCR in ethanol-treated mice (5 g/kg/day, i.g., 10 days + 24 hr), rat brain slice culture, and post-mortem human alcoholic brain. Results Ethanol treatment of mice increased brain mRNA and +IR protein expression of HMGB1, TLR2, TLR3, and TLR4. Post-mortem human alcoholic brain also showed increased HMGB1, TLR2, TLR3, and TLR4+IR cells that correlated with lifetime alcohol consumption as well as each other. Ethanol treatment of brain slice culture released HMGB1 into the media and induced the proinflammatory cytokine, IL-1β. Neutralizing antibodies to HMGB1 and small inhibitory mRNA to HMGB1 or TLR4 blunted ethanol induction of IL-1β. Conclusions Ethanol-induced HMGB1/TLR signaling contributes to induction of the proinflammatory cytokine, IL-1β. Increased expression of HMGB1, TLR2, TLR3, and TLR4 in alcoholic brain and in mice treated with ethanol suggests that chronic alcohol-induced brain neuroimmune activation occurs through HMGB1/TLR signaling. PMID:23206318

  1. Desloratadine citrate disodium injection, a potent histamine H(1) receptor antagonist, inhibits chemokine production in ovalbumin-induced allergic rhinitis guinea pig model and histamine-induced human nasal epithelial cells via inhibiting the ERK1/2 and NF-kappa B signal cascades.

    PubMed

    Chen, Meiling; Xu, Shuhong; Zhou, Peipei; He, Guangwei; Jie, Qiong; Wu, Yulin

    2015-11-15

    Chemokines have chemotactic properties on leukocyte subsets whose modulation plays a pivotal role in allergic inflammatory processes. Our present study was designed to investigate the anti-allergic and anti-inflammatory properties of desloratadine citrate disodium injection (DLC) and elucidate the molecular mechanisms of its anti-inflammatory properties. The anti-allergic effects of DLC were evaluated based on allergic symptoms, serological marker production and histological changes of the nasal mucosa in guinea pigs model of allergic rhinitis. The anti-inflammatory properties and molecular mechanisms of DLC were explored by studying the regulation of a set of chemokines and extracellular signal-regulated kinase (ERK)1/2 and nuclear factor-kappa B (NF-κB) pathways, after DLC treatment in guinea pigs model of allergic rhinitis in vivo and histamine-activated human nasal epithelial cells (HNECs) in vitro. In vivo model in guinea pigs, DLC alleviated the rhinitis symptoms, inhibited inflammatory cells infiltration in nasal lavage fluid (NLF) and histamine, monocyte chemotactic protein (MCP)-1, regulated on activation normal T cell expressed, and presumably secreted (RANTEs) and interleukin (IL)-8 release in sera and P-ERK1/2 and NF-κB activation in nasal mucosa. In vitro, DLC markedly inhibited histamine-induced production of MCP-1, RANTEs and IL-8 and suppressed c-Raf, mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK) and ERK1/2 activation in HNECs. These results provide evidence that DLC possesses potent anti-allergic and anti-inflammatory properties. The mechanism of action underlying DLC in allergic inflammation appears to be inhibition of the phosphorylation of ERK1/2, in addition to blocking of the NF-κB pathway.

  2. Increasing 14N NQR signal by 1H-14N level crossing with small magnetic fields.

    PubMed

    Thurber, Kent R; Sauer, Karen L; Buess, Michael L; Klug, Christopher A; Miller, Joel B

    2005-11-01

    NQR detection of materials, such as TNT, is hindered by the low signal-to-noise ratio at low NQR frequencies. Sweeping small (0-26 mT) magnetic fields to shift the (1)H NMR frequency relative to the (14)N NQR frequencies can provide a significant increase of the (14)N NQR signal-to-noise ratio. Three effects of (1)H-(14)N level crossing are demonstrated in diglycine hydrochloride and TNT. These effects are (1) transferring (1)H polarization to one or more of the (14)N transitions, including the use of an adiabatic flip of the (1)H polarization during the field sweep, (2) shortening the effective (14)N T(1) by the interaction of (1)H with the (14)N transitions, (3) "level transfer" effect where the third (14)N (spin 1) energy level or other (14)N sites with different NQR frequency are used as a reservoir of polarization which is transferred to the measured (14)N transition by the (1)H. The (14)N NQR signal-to-noise ratio can be increased by a factor of 2.5 for one (14)N site in diglycine hydrochloride (and 2.2 in TNT), even though the maximum (1)H frequency used in this work, 111 6 kHz, is only 30% larger than the measured (14)N frequencies (834 kHz for diglycine hydrochloride and 843 kHz for TNT).

  3. Kynurenine signaling increases DNA polymerase kappa expression and promotes genomic instability in glioblastoma cells

    PubMed Central

    Bostian, April C.L.; Maddukuri, Leena; Reed, Megan R.; Savenka, Tatsiana; Hartman, Jessica H.; Davis, Lauren; Pouncey, Dakota L.; Miller, Grover P.; Eoff, Robert L.

    2015-01-01

    Over-expression of the translesion synthesis polymerase (TLS pol) hpol κ in glioblastomas has been linked to a poor patient prognosis; however, the mechanism promoting higher expression in these tumors remains unknown. We determined that activation of the aryl hydrocarbon receptor (AhR) pathway in glioblastoma cells leads to increased hpol κ mRNA and protein levels. We blocked nuclear translocation and DNA binding by the AhR in glioblastoma cells using a small-molecule and observed decreased hpol κ expression. Pharmacological inhibition of tryptophan-2,3-dioxygenase (TDO), the enzyme largely responsible for activating the AhR in glioblastomas, led to a decrease in the endogenous AhR agonist kynurenine (Kyn) and a corresponding decrease in hpol κ protein levels. Importantly, we discovered that inhibiting TDO activity, AhR signaling, or suppressing hpol κ expression with RNA interference led to decreased chromosomal damage in glioblastoma cells. Epistasis assays further supported the idea that TDO activity, activation of AhR signaling and the resulting over-expression of hpol κ function primarily in the same pathway to increase endogenous DNA damage. These findings indicate that up-regulation of hpol κ through glioblastoma-specific TDO activity and activation of AhR signaling likely contributes to the high levels of replication stress and genomic instability observed in these tumors. PMID:26651356

  4. Multisegment coloboma in a case of Marfan syndrome: another possible effect of increased TGFβ signaling.

    PubMed

    LeBlanc, Shannon K; Taranath, Deepa; Morris, Scott; Barnett, Christopher P

    2014-02-01

    Colobomata are etiologically heterogeneous and may occur as an isolated defect or as a feature of a variety of single-gene disorders, chromosomal syndromes, or malformation syndromes. Although not classically associated with Marfan syndrome, colobomata have been described in several reports of Marfan syndrome, typically involving the lens and rarely involving other ocular structures. While colobomata of the lens have been described in Marfan syndrome, there are very few reports of coloboma involving other ocular structures. We report a newborn boy presenting with coloboma of the iris, lens, retina, and optic disk who was subsequently diagnosed with Marfan syndrome. Marfan syndrome is a disorder of increased TGFβ signaling, and recent work in the mouse model suggests a role for TGFβ signaling in eye development and coloboma formation, suggesting a causal association between Marfan syndrome and coloboma.

  5. The Role of Chemokines in Promoting Colorectal Cancer Invasion/Metastasis

    PubMed Central

    Itatani, Yoshiro; Kawada, Kenji; Inamoto, Susumu; Yamamoto, Takamasa; Ogawa, Ryotaro; Taketo, Makoto Mark; Sakai, Yoshiharu

    2016-01-01

    Colorectal cancer (CRC) is one of the leading causes of cancer-related death worldwide. Although most of the primary CRC can be removed by surgical resection, advanced tumors sometimes show recurrences in distant organs such as the liver, lung, lymph node, bone or peritoneum even after complete resection of the primary tumors. In these advanced and metastatic CRC, it is the tumor-stroma interaction in the tumor microenvironment that often promotes cancer invasion and/or metastasis through chemokine signaling. The tumor microenvironment contains numerous host cells that may suppress or promote cancer aggressiveness. Several types of host-derived myeloid cells reside in the tumor microenvironment, and the recruitment of them is under the control of chemokine signaling. In this review, we focus on the functions of chemokine signaling that may affect tumor immunity by recruiting several types of bone marrow-derived cells (BMDC) to the tumor microenvironment of CRC. PMID:27136535

  6. The Role of Chemokines in Promoting Colorectal Cancer Invasion/Metastasis.

    PubMed

    Itatani, Yoshiro; Kawada, Kenji; Inamoto, Susumu; Yamamoto, Takamasa; Ogawa, Ryotaro; Taketo, Makoto Mark; Sakai, Yoshiharu

    2016-04-28

    Colorectal cancer (CRC) is one of the leading causes of cancer-related death worldwide. Although most of the primary CRC can be removed by surgical resection, advanced tumors sometimes show recurrences in distant organs such as the liver, lung, lymph node, bone or peritoneum even after complete resection of the primary tumors. In these advanced and metastatic CRC, it is the tumor-stroma interaction in the tumor microenvironment that often promotes cancer invasion and/or metastasis through chemokine signaling. The tumor microenvironment contains numerous host cells that may suppress or promote cancer aggressiveness. Several types of host-derived myeloid cells reside in the tumor microenvironment, and the recruitment of them is under the control of chemokine signaling. In this review, we focus on the functions of chemokine signaling that may affect tumor immunity by recruiting several types of bone marrow-derived cells (BMDC) to the tumor microenvironment of CRC.

  7. Molecular requirements for sorting of the chemokine interleukin-8/CXCL8 to endothelial Weibel-Palade bodies.

    PubMed

    Hol, Johanna; Küchler, Axel M; Johansen, Finn-Eirik; Dalhus, Bjørn; Haraldsen, Guttorm; Oynebråten, Inger

    2009-08-28

    Sorting of proteins to Weibel-Palade bodies (WPB) of endothelial cells allows rapid regulated secretion of leukocyte-recruiting P-selectin and chemokines as well as procoagulant von Willebrand factor (VWF). Here we show by domain swap studies that the exposed aspartic acid in loop 2 (Ser(44)-Asp(45)-Gly(46)) of the CXC chemokine interleukin (IL)-8 is crucial for targeting to WPB. Loop 2 also governs sorting of chemokines to alpha-granules of platelets, but the fingerprint of the loop 2 of these chemokines differs from that of IL-8. On the other hand, loop 2 of IL-8 closely resembles a surface-exposed sequence of the VWF propeptide, the region of VWF that directs sorting of the protein to WPB. We conclude that loop 2 of IL-8 constitutes a critical signal for sorting to WPB and propose a general role for this loop in the sorting of chemokines to compartments of regulated secretion.

  8. Similar pattern of chemokines after acute viral and bacterial infection.

    PubMed

    Vyas, Ashish Kumar

    2017-01-27

    Read with great interest the article by Cavalcanti et al (1). Which describes the levels of chemokine such as MCP-1, RANETS, MIG and IP-10 in children with sepsis community acquired pneumonia and skin abscess. Author has found increased levels of RANETS in all infections mentioned above. Interestingly IP-10 was significantly increased in sepsis groups with low levels of MCP1. This article is protected by copyright. All rights reserved.

  9. Mixed lactate and caffeine compound increases satellite cell activity and anabolic signals for muscle hypertrophy.

    PubMed

    Oishi, Yoshimi; Tsukamoto, Hayato; Yokokawa, Takumi; Hirotsu, Keisuke; Shimazu, Mariko; Uchida, Kenji; Tomi, Hironori; Higashida, Kazuhiko; Iwanaka, Nobumasa; Hashimoto, Takeshi

    2015-03-15

    We examined whether a mixed lactate and caffeine compound (LC) could effectively elicit proliferation and differentiation of satellite cells or activate anabolic signals in skeletal muscles. We cultured C2C12 cells with either lactate or LC for 6 h. We found that lactate significantly increased myogenin and follistatin protein levels and phosphorylation of P70S6K while decreasing the levels of myostatin relative to the control. LC significantly increased protein levels of Pax7, MyoD, and Ki67 in addition to myogenin, relative to control. LC also significantly increased follistatin expression relative to control and stimulated phosphorylation of mTOR and P70S6K. In an in vivo study, male F344/DuCrlCrlj rats were assigned to control (Sed, n = 10), exercise (Ex, n = 12), and LC supplementation (LCEx, n = 13) groups. LC was orally administered daily. The LCEx and Ex groups were exercised on a treadmill, running for 30 min at low intensity every other day for 4 wk. The LCEx group experienced a significant increase in the mass of the gastrocnemius (GA) and tibialis anterior (TA) relative to both the Sed and Ex groups. Furthermore, the LCEx group showed a significant increase in the total DNA content of TA compared with the Sed group. The LCEx group experienced a significant increase in myogenin and follistatin expression of GA relative to the Ex group. These results suggest that administration of LC can effectively increase muscle mass concomitant with elevated numbers of myonuclei, even with low-intensity exercise training, via activated satellite cells and anabolic signals.

  10. Increase of global monsoon area and precipitation under global warming: A robust signal?

    NASA Astrophysics Data System (ADS)

    Hsu, Pang-chi; Li, Tim; Luo, Jing-Jia; Murakami, Hiroyuki; Kitoh, Akio; Zhao, Ming

    2012-03-01

    Monsoons, the most energetic tropical climate system, exert a great social and economic impact upon billions of people around the world. The global monsoon precipitation had an increasing trend over the past three decades. Whether or not this increasing trend will continue in the 21st century is investigated, based on simulations of three high-resolution atmospheric general circulation models that were forced by different future sea surface temperature (SST) warming patterns. The results show that the global monsoon area, precipitation and intensity all increase consistently among the model projections. This indicates that the strengthened global monsoon is a robust signal across the models and SST patterns explored here. The increase of the global monsoon precipitation is attributed to the increases of moisture convergence and surface evaporation. The former is caused by the increase of atmospheric water vapor and the latter is due to the increase of SST. The effect of the moisture and evaporation increase is offset to a certain extent by the weakening of the monsoon circulation.

  11. Multiplane wave imaging increases signal-to-noise ratio in ultrafast ultrasound imaging

    NASA Astrophysics Data System (ADS)

    Tiran, Elodie; Deffieux, Thomas; Correia, Mafalda; Maresca, David; Osmanski, Bruno-Felix; Sieu, Lim-Anna; Bergel, Antoine; Cohen, Ivan; Pernot, Mathieu; Tanter, Mickael

    2015-11-01

    Ultrafast imaging using plane or diverging waves has recently enabled new ultrasound imaging modes with improved sensitivity and very high frame rates. Some of these new imaging modalities include shear wave elastography, ultrafast Doppler, ultrafast contrast-enhanced imaging and functional ultrasound imaging. Even though ultrafast imaging already encounters clinical success, increasing even more its penetration depth and signal-to-noise ratio for dedicated applications would be valuable. Ultrafast imaging relies on the coherent compounding of backscattered echoes resulting from successive tilted plane waves emissions; this produces high-resolution ultrasound images with a trade-off between final frame rate, contrast and resolution. In this work, we introduce multiplane wave imaging, a new method that strongly improves ultrafast images signal-to-noise ratio by virtually increasing the emission signal amplitude without compromising the frame rate. This method relies on the successive transmissions of multiple plane waves with differently coded amplitudes and emission angles in a single transmit event. Data from each single plane wave of increased amplitude can then be obtained, by recombining the received data of successive events with the proper coefficients. The benefits of multiplane wave for B-mode, shear wave elastography and ultrafast Doppler imaging are experimentally demonstrated. Multiplane wave with 4 plane waves emissions yields a 5.8  ±  0.5 dB increase in signal-to-noise ratio and approximately 10 mm in penetration in a calibrated ultrasound phantom (0.7 d MHz-1 cm-1). In shear wave elastography, the same multiplane wave configuration yields a 2.07  ±  0.05 fold reduction of the particle velocity standard deviation and a two-fold reduction of the shear wave velocity maps standard deviation. In functional ultrasound imaging, the mapping of cerebral blood volume results in a 3 to 6 dB increase of the contrast-to-noise ratio in deep

  12. The Anti-inflammatory Protein TSG-6 Regulates Chemokine Function by Inhibiting Chemokine/Glycosaminoglycan Interactions*

    PubMed Central

    Dyer, Douglas P.; Salanga, Catherina L.; Johns, Scott C.; Valdambrini, Elena; Fuster, Mark M.; Milner, Caroline M.; Day, Anthony J.; Handel, Tracy M.

    2016-01-01

    TNF-stimulated gene-6 (TSG-6) is a multifunctional protein secreted in response to pro-inflammatory stimuli by a wide range of cells, including neutrophils, monocytes, and endothelial cells. It has been shown to mediate anti-inflammatory and protective effects when administered in disease models, in part, by reducing neutrophil infiltration. Human TSG-6 inhibits neutrophil migration by binding CXCL8 through its Link module (Link_TSG6) and interfering with the presentation of CXCL8 on cell-surface glycosaminoglycans (GAGs), an interaction that is vital for the function of many chemokines. TSG-6 was also found to interact with chemokines CXCL11 and CCL5, suggesting the possibility that it may function as a broad specificity chemokine-binding protein, functionally similar to those encoded by viruses. This study was therefore undertaken to explore the ability of TSG-6 to regulate the function of other chemokines. Herein, we demonstrate that Link_TSG6 binds chemokines from both the CXC and CC families, including CXCL4, CXCL12, CCL2, CCL5, CCL7, CCL19, CCL21, and CCL27. We also show that the Link_TSG6-binding sites on chemokines overlap with chemokine GAG-binding sites, and that the affinities of Link_TSG6 for these chemokines (KD values 1–85 nm) broadly correlate with chemokine-GAG affinities. Link_TSG6 also inhibits chemokine presentation on endothelial cells not only through a direct interaction with chemokines but also by binding and therefore masking the availability of GAGs. Along with previous work, these findings suggest that TSG-6 functions as a pluripotent regulator of chemokines by modulating chemokine/GAG interactions, which may be a major mechanism by which TSG-6 produces its anti-inflammatory effects in vivo. PMID:27044744

  13. Stacked phased array coils for increasing the signal-to-noise ratio in magnetic resonance imaging.

    PubMed

    Dandan Liang; Hon Tat Hui; Tat Soon Yeo; Bing Keong Li

    2013-02-01

    A new concept of using a stacked phased coil array to increase the signal-to-circuit noise ratio (SCNR) in magnetic resonance imaging (MRI) is introduced. Unlike conventional phased coil arrays, the proposed stacked phased coil array is constructed by stacking the coil elements closely together in the vertical direction. Through a proper combination of the coil terminal voltages, the SCNR is shown to increase with the square root of the number of coil elements. A prototype two-element array is constructed and an experimental method is designed to determine the combiner coefficients in a simulated MRI electromagnetic field environment. The experimental results show that the mutual coupling effect among the array coils can be totally removed and the combiner output voltage increases with the number of coil elements. This demonstrates the feasibility of the proposed method.

  14. Hostility is related to clusters of T-cell cytokines and chemokines in healthy men.

    PubMed

    Mommersteeg, Paula M C; Vermetten, Eric; Kavelaars, Annemieke; Geuze, Elbert; Heijnen, Cobi J

    2008-09-01

    Hostility is a risk factor for adverse health outcomes as diverse as cardiovascular disease and post-traumatic stress disorder (PTSD). Cytokines have been suggested to mediate this relationship. We investigated whether in healthy men a relation existed between hostility and T-cell mitogen-induced cytokines and chemokines. Male Dutch military personnel (n=304) were included before deployment. Eleven cytokines and chemokines were measured in supernatants of T-cell mitogen-stimulated whole blood cultures by multiplex immunoassay. Factor analysis was used to identify clusters of cytokines and chemokines. In a regression analysis hostility was related to the cytokine/chemokine clusters, and the potential risk factors age, BMI, smoking, drinking, previous deployment, early life trauma and depression. Explorative factor analysis showed four functional clusters; a pro-inflammatory factor (IL-2, TNFalpha, IFNgamma), an anti-inflammatory factor (IL-4, IL-5, IL-10), IL-6/chemokine factor (IL-6, MCP-1, RANTES, IP-10), and MIF. Hostility was significantly related to decreased IL-6/chemokine secretion and increased pro- and anti-inflammatory cytokines. There was an inverse relation between age and hostility scores. Early life trauma and depression were positively and independently related to hostility as well. This study represents a novel way of investigating the relation between cytokines and psychological characteristics. Cytokines/chemokines clustered into functional factors, which were related to hostility in healthy males. Moreover this relation appeared to be independent of reported depression and early trauma.

  15. AHNAK deficiency promotes browning and lipolysis in mice via increased responsiveness to β-adrenergic signalling

    PubMed Central

    Shin, Jae Hoon; Lee, Seo Hyun; Kim, Yo Na; Kim, Il Yong; Kim, Youn Ju; Kyeong, Dong Soo; Lim, Hee Jung; Cho, Soo Young; Choi, Junhee; Wi, Young Jin; Choi, Jae-Hoon; Yoon, Yeo Sung; Bae, Yun Soo; Seong, Je Kyung

    2016-01-01

    In adipose tissue, agonists of the β3-adrenergic receptor (ADRB3) regulate lipolysis, lipid oxidation, and thermogenesis. The deficiency in the thermogenesis induced by neuroblast differentiation-associated protein AHNAK in white adipose tissue (WAT) of mice fed a high-fat diet suggests that AHNAK may stimulate energy expenditure via development of beige fat. Here, we report that AHNAK deficiency promoted browning and thermogenic gene expression in WAT but not in brown adipose tissue of mice stimulated with the ADRB3 agonist CL-316243. Consistent with the increased thermogenesis, Ahnak−/− mice exhibited an increase in energy expenditure, accompanied by elevated mitochondrial biogenesis in WAT depots in response to CL-316243. Additionally, AHNAK-deficient WAT contained more eosinophils and higher levels of type 2 cytokines (IL-4/IL-13) to promote browning of WAT in response to CL-316243. This was associated with enhanced sympathetic tone in the WAT via upregulation of adrb3 and tyrosine hydroxylase (TH) in response to β-adrenergic activation. CL-316243 activated PKA signalling and enhanced lipolysis, as evidenced by increased phosphorylation of hormone-sensitive lipase and release of free glycerol in Ahnak−/− mice compared to wild-type mice. Overall, these findings suggest an important role of AHNAK in the regulation of thermogenesis and lipolysis in WAT via β-adrenergic signalling. PMID:26987950

  16. Blocking Hedgehog release from pancreatic cancer cells increases paracrine signaling potency.

    PubMed

    Damhofer, Helene; Veenstra, Veronique L; Tol, Johanna A M G; van Laarhoven, Hanneke W M; Medema, Jan Paul; Bijlsma, Maarten F

    2015-01-01

    Members of the Hedgehog (Hh) family of morphogens play crucial roles in development but are also involved in the progression of certain types of cancer. Despite being synthesized as hydrophobic dually lipid-modified molecules, and thus being strongly membrane-associated, Hh ligands are able to spread through tissues and act on target cells several cell diameters away. Various mechanisms that mediate Hh release have been discussed in recent years; however, little is known about dispersion of this ligand from cancer cells. Using co-culture models in conjunction with a newly developed reporter system, we were able to show that different members of the ADAM family of metalloproteinases strongly contribute to the release of endogenous bioactive Hh from pancreatic cancer cells, but that this solubilization decreases the potency of cancer cells to signal to adjacent stromal cells in direct co-culture models. These findings imply that under certain conditions, cancer-cell-tethered Hh molecules are the more potent signaling activators and that retaining Hh on the surface of cancer cells can unexpectedly increase the effective signaling range of this ligand, depending on tissue context.

  17. Brain-computer interfaces increase whole-brain signal to noise.

    PubMed

    Papageorgiou, T Dorina; Lisinski, Jonathan M; McHenry, Monica A; White, Jason P; LaConte, Stephen M

    2013-08-13

    Brain-computer interfaces (BCIs) can convert mental states into signals to drive real-world devices, but it is not known if a given covert task is the same when performed with and without BCI-based control. Using a BCI likely involves additional cognitive processes, such as multitasking, attention, and conflict monitoring. In addition, it is challenging to measure the quality of covert task performance. We used whole-brain classifier-based real-time functional MRI to address these issues, because the method provides both classifier-based maps to examine the neural requirements of BCI and classification accuracy to quantify the quality of task performance. Subjects performed a covert counting task at fast and slow rates to control a visual interface. Compared with the same task when viewing but not controlling the interface, we observed that being in control of a BCI improved task classification of fast and slow counting states. Additional BCI control increased subjects' whole-brain signal-to-noise ratio compared with the absence of control. The neural pattern for control consisted of a positive network comprised of dorsal parietal and frontal regions and the anterior insula of the right hemisphere as well as an expansive negative network of regions. These findings suggest that real-time functional MRI can serve as a platform for exploring information processing and frontoparietal and insula network-based regulation of whole-brain task signal-to-noise ratio.

  18. Anabolic steroids activate calcineurin-NFAT signaling and thereby increase myotube size and reduce denervation atrophy.

    PubMed

    Qin, Weiping; Pan, Jiangping; Wu, Yong; Bauman, William A; Cardozo, Christopher

    2015-01-05

    Anabolic androgens have been shown to reduce muscle loss due to immobilization, paralysis and many other medical conditions, but the molecular basis for these actions is poorly understood. We have recently demonstrated that nandrolone, a synthetic androgen, slows muscle atrophy after nerve transection associated with down-regulation of regulator of calcineurin 2 (RCAN2), a calcineurin inhibitor, suggesting a possible role of calcineurin-NFAT signaling. To test this possibility, rat gastrocnemius muscle was analyzed at 56 days after denervation. In denervated muscle, calcineurin activity declined and NFATc4 was excluded from the nucleus and these effects were reversed by nandrolone. Similarly, nandrolone increased calcineurin activity and nuclear NFATc4 levels in cultured L6 myotubes. Nandrolone also induced cell hypertrophy that was blocked by cyclosporin A or overexpression of RCAN2. Finally protection against denervation atrophy by nandrolone in rats was blocked by cyclosporin A. These results demonstrate for the first time that nandrolone activates calcineurin-NFAT signaling, and that such signaling is important in nandrolone-induced cell hypertrophy and protection against paralysis-induced muscle atrophy.

  19. Involvement of chemokine receptors in breast cancer metastasis

    NASA Astrophysics Data System (ADS)

    Müller, Anja; Homey, Bernhard; Soto, Hortensia; Ge, Nianfeng; Catron, Daniel; Buchanan, Matthew E.; McClanahan, Terri; Murphy, Erin; Yuan, Wei; Wagner, Stephan N.; Barrera, Jose Luis; Mohar, Alejandro; Verástegui, Emma; Zlotnik, Albert

    2001-03-01

    Breast cancer is characterized by a distinct metastatic pattern involving the regional lymph nodes, bone marrow, lung and liver. Tumour cell migration and metastasis share many similarities with leukocyte trafficking, which is critically regulated by chemokines and their receptors. Here we report that the chemokine receptors CXCR4 and CCR7 are highly expressed in human breast cancer cells, malignant breast tumours and metastases. Their respective ligands CXCL12/SDF-1α and CCL21/6Ckine exhibit peak levels of expression in organs representing the first destinations of breast cancer metastasis. In breast cancer cells, signalling through CXCR4 or CCR7 mediates actin polymerization and pseudopodia formation, and subsequently induces chemotactic and invasive responses. In vivo, neutralizing the interactions of CXCL12/CXCR4 significantly impairs metastasis of breast cancer cells to regional lymph nodes and lung. Malignant melanoma, which has a similar metastatic pattern as breast cancer but also a high incidence of skin metastases, shows high expression levels of CCR10 in addition to CXCR4 and CCR7. Our findings indicate that chemokines and their receptors have a critical role in determining the metastatic destination of tumour cells.

  20. Dynamics and thermodynamic properties of CXCL7 chemokine.

    PubMed

    Herring, Charles A; Singer, Christopher M; Ermakova, Elena A; Khairutdinov, Bulat I; Zuev, Yuriy F; Jacobs, Donald J; Nesmelova, Irina V

    2015-11-01

    Chemokines form a family of signaling proteins mainly responsible for directing the traffic of leukocytes, where their biological activity can be modulated by their oligomerization state. We characterize the dynamics and thermodynamic stability of monomer and homodimer structures of CXCL7, one of the most abundant platelet chemokines, using experimental methods that include circular dichroism (CD) and nuclear magnetic resonance (NMR) spectroscopy, and computational methods that include the anisotropic network model (ANM), molecular dynamics (MD) simulations and the distance constraint model (DCM). A consistent picture emerges for the effects of dimerization and Cys5-Cys31 and Cys7-Cys47 disulfide bonds formation. The presence of disulfide bonds is not critical for maintaining structural stability in the monomer or dimer, but the monomer is destabilized more than the dimer upon removal of disulfide bonds. Disulfide bonds play a key role in shaping the characteristics of native state dynamics. The combined analysis shows that upon dimerization flexibly correlated motions are induced between the 30s and 50s loop within each monomer and across the dimer interface. Interestingly, the greatest gain in flexibility upon dimerization occurs when both disulfide bonds are present, and the homodimer is least stable relative to its two monomers. These results suggest that the highly conserved disulfide bonds in chemokines facilitate a structural mechanism that is tuned to optimally distinguish functional characteristics between monomer and dimer.

  1. Characterisation of SNP haplotype structure in chemokine and chemokine receptor genes using CEPH pedigrees and statistical estimation.

    PubMed

    Clark, Vanessa J; Dean, Michael

    2004-03-01

    Chemokine signals and their cell-surface receptors are important modulators of HIV-1 disease and cancer. To aid future case/control association studies, aim to further characterise the haplotype structure of variation in chemokine and chemokine receptor genes. To perform haplotype analysis in a population-based association study, haplotypes must be determined by estimation, in the absence of family information or laboratory methods to establish phase. Here, test the accuracy of estimates of haplotype frequency and linkage disequilibrium by comparing estimated haplotypes generated with the expectation maximisation (EM) algorithm to haplotypes determined from Centre d'Etude Polymorphisme Humain (CEPH) pedigree data. To do this, they have characterised haplotypes comprising alleles at 11 biallelic loci in four chemokine receptor genes (CCR3, CCR2, CCR5 and CCRL2), which span 150 kb on chromosome 3p21, and haplotyes of nine biallelic loci in six chemokine genes [MCP-1(CCL2), Eotaxin(CCL11), RANTES(CCL5), MPIF-1(CCL23), PARC(CCL18) and MIP-1alpha(CCL3)] on chromosome 17q11-12. Forty multi-generation CEPH families, totalling 489 individuals, were genotyped by the TaqMan 5'-nuclease assay. Phased haplotypes and haplotypes estimated from unphased genotypes were compared in 103 grandparents who were assumed to have mated at random. For the 3p21 single nucleotide polymorphism (SNP) data, haplotypes determined by pedigree analysis and haplotypes generated by the EM algorithm were nearly identical. Linkage disequilibrium, measured by the D' statistic, was nearly maximal across the 150 kb region, with complete disequilibrium maintained at the extremes between CCR3-Y17Y and CCRL2-I243V. D'-values calculated from estimated haplotypes on 3p21 had high concordance with pairwise comparisons between pedigree-phased chromosomes. Conversely, there was less agreement between analyses of haplotype frequencies and linkage disequilibrium using estimated haplotypes when compared with

  2. Chemokines integrate JAK/STAT and G-protein pathways during chemotaxis and calcium flux responses.

    PubMed

    Soriano, Silvia F; Serrano, Antonio; Hernanz-Falcón, Patricia; Martín de Ana, Ana; Monterrubio, María; Martínez, Carlos; Rodríguez-Frade, J Miguel; Mellado, Mario

    2003-05-01

    The JAK/STAT (Janus kinase / signaling transducer and activator of transcription) signaling pathway is implicated in converting stationary epithelial cells to migratory cells. In mammals, migratory responses are activated by chemoattractant proteins, including chemokines. We found that by binding to seven-transmembrane G-protein-coupled receptors, chemokines activate the JAK/STAT pathway to trigger chemotactic responses. We show that chemokine-mediated JAK/STAT activation is critical for G-protein induction and for phospholipase C-beta dependent Ca(2+) flux; in addition, pharmacological inhibition of JAK or mutation of the JAK kinase domain causes defects in both responses. Furthermore, G alpha(i) association with the receptor is dependent on JAK activation, and the chemokine-mediated Ca(2+) flux that requires phospholipase C-beta activity takes place downstream of JAK kinases. The chemokines thus employ a mechanism that links heterologous signaling pathways--G proteins and tyrosine kinases--in a network that may be essential for mediating their pleiotropic responses.

  3. Chemokines CCL2, 3, 14 stimulate macrophage bone marrow homing, proliferation, and polarization in multiple myeloma.

    PubMed

    Li, Yi; Zheng, Yuhuan; Li, Tianshu; Wang, Qiang; Qian, Jianfei; Lu, Yong; Zhang, Mingjun; Bi, Enguang; Yang, Maojie; Reu, Frederic; Yi, Qing; Cai, Zhen

    2015-09-15

    We previously showed that macrophages (MΦs) infiltrate the bone marrow (BM) of patients with myeloma and may play a role in drug resistance. This study analyzed chemokines expressed by myeloma BM that are responsible for recruiting monocytes to the tumor bed. We found that chemokines CCL3, CCL14, and CCL2 were highly expressed by myeloma and BM cells, and the levels of CCL14 and CCL3 in myeloma BM positively correlated with the percentage of BM-infiltrating MΦs. In vitro, these chemokines were responsible for chemoattracting human monocytes to tumor sites and in vivo for MΦ infiltration into myeloma-bearing BM in the 5TGM1 mouse model. Surprisingly, we also found that these chemokines stimulated MΦ in vitro proliferation induced by myeloma cells and in vivo in a human myeloma xenograft SCID mouse model. The chemokines also activated normal MΦ polarization and differentiation into myeloma-associated MΦs. Western blot analysis revealed that these chemokines promoted growth and survival signaling in MΦs via activating the PI3K/Akt and ERK MAPK pathways and c-myc expression. Thus, this study provides novel insight into the mechanism of MΦ infiltration of BM and also potential targets for improving the efficacy of chemotherapy in myeloma.

  4. Polarization of chemokine receptors to the leading edge during lymphocyte chemotaxis.

    PubMed

    Nieto, M; Frade, J M; Sancho, D; Mellado, M; Martinez-A, C; Sánchez-Madrid, F

    1997-07-07

    Leukocyte migration in response to cell attractant gradients or chemotaxis is a key phenomenon both in cell movement and in the inflammatory response. Chemokines are quite likely to be the key molecules directing migration of leukocytes that involve cell polarization with generation of specialized cell compartments. The precise mechanism of leukocyte chemoattraction is not known, however. In this study, we demonstrate that the CC chemokine receptors CCR2 and CCR5, but not cytokine receptors such as interleukin (IL)-2Ralpha, IL-2Rbeta, tumor necrosis factor receptor 1, or transforming growth factor betaR, are redistributed to a pole in T cells that are migrating in response to chemokines. Immunofluorescence and confocal microscopy studies show that the chemokine receptors concentrate at the leading edge of the cell on the flattened cell-substratum contact area, induced specifically by the signals that trigger cell polarization. The redistribution of chemokine receptors is blocked by pertussis toxin and is dependent on cell adhesion through integrin receptors, which mediate cell migration. Chemokine receptor expression on the leading edge of migrating polarized lymphocytes appears to act as a sensor mechanism for the directed migration of leukocytes through a chemoattractant gradient.

  5. Extracellular matrix hyaluronan signals via its CD44 receptor in the increased responsiveness to mechanical stimulation.

    PubMed

    Ferrari, L F; Araldi, D; Bogen, O; Levine, J D

    2016-06-02

    We propose that the extracellular matrix (ECM) signals CD44, a hyaluronan receptor, to increase the responsiveness to mechanical stimulation in the rat hind paw. We report that intradermal injection of hyaluronidase induces mechanical hyperalgesia, that is inhibited by co-administration of a CD44 receptor antagonist, A5G27. The intradermal injection of low (LMWH) but not high (HMWH) molecular weight hyaluronan also induces mechanical hyperalgesia, an effect that was attenuated by pretreatment with HMWH or A5G27. Pretreatment with HMWH also attenuated the hyperalgesia induced by hyaluronidase. Similarly, intradermal injection of A6, a CD44 receptor agonist, produced hyperalgesia that was inhibited by HMWH and A5G27. Inhibitors of protein kinase A (PKA) and Src, but not protein kinase C (PKC), significantly attenuated the hyperalgesia induced by both A6 and LMWH. Finally, to determine if CD44 receptor signaling is involved in a preclinical model of inflammatory pain, we evaluated the effect of A5G27 and HMWH on the mechanical hyperalgesia associated with the inflammation induced by carrageenan. Both A5G27 and HMWH attenuated carrageenan-induced mechanical hyperalgesia. Thus, while LMWH acts at its cognate receptor, CD44, to induce mechanical hyperalgesia, HMWH acts at the same receptor as an antagonist. That the local administration of HMWH or A5G27 inhibits carrageenan-induced hyperalgesia supports the suggestion that carrageenan produces changes in the ECM that contributes to inflammatory pain. These studies define a clinically relevant role for signaling by the hyaluronan receptor, CD44, in increased responsiveness to mechanical stimulation.

  6. Neuroinflammation in Alzheimer’s disease: chemokines produced by astrocytes and chemokine receptors

    PubMed Central

    Liu, Chang; Cui, Guohong; Zhu, Meiping; Kang, Xiangping; Guo, Haidong

    2014-01-01

    Chemokines secreted by astrocytes play multiple roles in the pathology of Alzheimer’s disease, a chronic inflammation disorder of central nervous system. The level of chemokines in serum, cerebrospinal fluid and brain tissue and their receptors both significantly changed in patients with Alzheimer’s disease. In this review, we briefly summarized the involvement of astrocytes and chemokines in Alzheimer’s disease, and the role of chemokine/chemokine receptors in the occurrence and development of Alzheimer’s disease. Clarification of the involvement of chemokines and their receptors, such as MCP-1/CCR2, fractalkine/CX3CR1, SDF-1α/CXCR4, MIP-1α/CCR5, IP-10/CXCR3, IL-8/CXCR1, CXCR2, and RANTES/CCR1, CCR3, CCR5, will provide a new strategy and more specific targets for the treatment of Alzheimer’s disease. PMID:25674199

  7. Regulation of Chemokine Activity – A Focus on the Role of Dipeptidyl Peptidase IV/CD26

    PubMed Central

    Metzemaekers, Mieke; Van Damme, Jo; Mortier, Anneleen; Proost, Paul

    2016-01-01

    Chemokines are small, chemotactic proteins that play a crucial role in leukocyte migration and are, therefore, essential for proper functioning of the immune system. Chemokines exert their chemotactic effect by activation of chemokine receptors, which are G protein-coupled receptors (GPCRs), and interaction with glycosaminoglycans (GAGs). Furthermore, the exact chemokine function is modulated at the level of posttranslational modifications. Among the different types of posttranslational modifications that were found to occur in vitro and in vivo, i.e., proteolysis, citrullination, glycosylation, and nitration, NH2-terminal proteolysis of chemokines has been described most intensively. Since the NH2-terminal chemokine domain mediates receptor interaction, NH2-terminal modification by limited proteolysis or amino acid side chain modification can drastically affect their biological activity. An enzyme that has been shown to provoke NH2-terminal proteolysis of various chemokines is dipeptidyl peptidase IV or CD26. This multifunctional protein is a serine protease that preferably cleaves dipeptides from the NH2-terminal region of peptides and proteins with a proline or alanine residue in the penultimate position. Various chemokines possess such a proline or alanine residue, and CD26-truncated forms of these chemokines have been identified in cell culture supernatant as well as in body fluids. The effects of CD26-mediated proteolysis in the context of chemokines turned out to be highly complex. Depending on the chemokine ligand, loss of these two NH2-terminal amino acids can result in either an increased or a decreased biological activity, enhanced receptor specificity, inactivation of the chemokine ligand, or generation of receptor antagonists. Since chemokines direct leukocyte migration in homeostatic as well as pathophysiologic conditions, CD26-mediated proteolytic processing of these chemotactic proteins may have significant consequences for appropriate functioning

  8. Spatial covert attention increases contrast sensitivity across the CSF: support for signal enhancement

    NASA Technical Reports Server (NTRS)

    Carrasco, M.; Penpeci-Talgar, C.; Eckstein, M.

    2000-01-01

    This study is the first to report the benefits of spatial covert attention on contrast sensitivity in a wide range of spatial frequencies when a target alone was presented in the absence of a local post-mask. We used a peripheral precue (a small circle indicating the target location) to explore the effects of covert spatial attention on contrast sensitivity as assessed by orientation discrimination (Experiments 1-4), detection (Experiments 2 and 3) and localization (Experiment 3) tasks. In all four experiments the target (a Gabor patch ranging in spatial frequency from 0.5 to 10 cpd) was presented alone in one of eight possible locations equidistant from fixation. Contrast sensitivity was consistently higher for peripherally- than for neutrally-cued trials, even though we eliminated variables (distracters, global masks, local masks, and location uncertainty) that are known to contribute to an external noise reduction explanation of attention. When observers were presented with vertical and horizontal Gabor patches an external noise reduction signal detection model accounted for the cueing benefit in a discrimination task (Experiment 1). However, such a model could not account for this benefit when location uncertainty was reduced, either by: (a) Increasing overall performance level (Experiment 2); (b) increasing stimulus contrast to enable fine discriminations of slightly tilted suprathreshold stimuli (Experiment 3); and (c) presenting a local post-mask (Experiment 4). Given that attentional benefits occurred under conditions that exclude all variables predicted by the external noise reduction model, these results support the signal enhancement model of attention.

  9. Nutrient signaling in protein homeostasis: an increase in quantity at the expense of quality.

    PubMed

    Conn, Crystal S; Qian, Shu-Bing

    2013-04-16

    The discovery that rapamycin extends the life span of diverse organisms has triggered many studies aimed at identifying the underlying molecular mechanisms. Mammalian target of rapamycin complex 1 (mTORC1) regulates cell growth and may regulate organismal aging by controlling mRNA translation. However, how inhibiting mTORC1 and decreasing protein synthesis can extend life span remains an unresolved issue. We showed that constitutively active mTORC1 signaling increased general protein synthesis but unexpectedly reduced the quality of newly synthesized polypeptides. We demonstrated that constitutively active mTORC1 decreased translation fidelity by increasing the speed of ribosomal elongation. Conversely, rapamycin treatment restored the quality of newly synthesized polypeptides mainly by slowing the rate of ribosomal elongation. We also found distinct roles for mTORC1 downstream targets in maintaining protein homeostasis. Loss of S6 kinases, but not 4E-BP family proteins, which are both involved in regulation of translation, attenuated the effects of rapamycin on the quality of newly translated proteins. Our results reveal a mechanistic connection between mTORC1 and protein quality, highlighting the central role of nutrient signaling in growth and aging.

  10. Molecular cloning of porcine chemokine CXC motif ligand 2 (CXCL2) and mapping to the SSC8

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maternal recognition of pregnancy is accompanied by inflammatory responses with leukocytosis and increased levels of cytokines and chemokines. Human trophoblast cells secrete chemokine CXC motif ligand 1 (CXCL1)/Gro-a and other chemotactic proteins, while monocytes co-cultured with trophoblast cells...

  11. Increased Sucrose Accumulation Regulates Iron-Deficiency Responses by Promoting Auxin Signaling in Arabidopsis Plants.

    PubMed

    Lin, Xian Yong; Ye, Yi Quan; Fan, Shi Kai; Jin, Chong Wei; Zheng, Shao Jian

    2016-02-01

    Previous studies have identified that auxins acts upstream of nitric oxide in regulating iron deficiency responses in roots, but the upstream signaling molecule of auxins remains unknown. In this study, we showed that Fe deficiency increased sucrose (Suc) level in roots of Arabidopsis (Arabidopsis thaliana). Exogenous application of Suc further stimulated Fe deficiency-induced ferric-chelate-reductase (FCR) activity and expression of Fe acquisition-related genes FRO2, IRT1, and FIT in roots. The opposite patterns were observed in the dark treatment. In addition, FCR activity and expression of Fe acquisition-related genes were higher in the Suc high-accumulating transgenic plant 35S::SUC2 but were lower in the Suc low-accumulating mutant suc2-5 compared with wild-type plants under Fe-deficient conditions. Consequently, Fe deficiency tolerance was enhanced in 35S::SUC2 but was compromised in suc2-5. Exogenous Suc also increased root β-glucuronidase (GUS) activity in auxin-inducible reporter DR5-GUS transgenic plants under Fe deficiency. However, exogenous Suc failed to increase FCR activity and expression of Fe acquisition-related genes in the auxin transport-impaired mutants aux1-7 and pin1-1 as well as in the wild-type plants treated with an auxin transport inhibitor under Fe deficiency. In summary, we found that increased Suc accumulation is required for regulating Fe deficiency responses in plants, with auxins acting downstream in transmitting the Fe deficiency signal.

  12. Increased Sucrose Accumulation Regulates Iron-Deficiency Responses by Promoting Auxin Signaling in Arabidopsis Plants1

    PubMed Central

    Lin, Xian Yong; Ye, Yi Quan; Fan, Shi Kai

    2016-01-01

    Previous studies have identified that auxins acts upstream of nitric oxide in regulating iron deficiency responses in roots, but the upstream signaling molecule of auxins remains unknown. In this study, we showed that Fe deficiency increased sucrose (Suc) level in roots of Arabidopsis (Arabidopsis thaliana). Exogenous application of Suc further stimulated Fe deficiency-induced ferric-chelate-reductase (FCR) activity and expression of Fe acquisition-related genes FRO2, IRT1, and FIT in roots. The opposite patterns were observed in the dark treatment. In addition, FCR activity and expression of Fe acquisition-related genes were higher in the Suc high-accumulating transgenic plant 35S::SUC2 but were lower in the Suc low-accumulating mutant suc2-5 compared with wild-type plants under Fe-deficient conditions. Consequently, Fe deficiency tolerance was enhanced in 35S::SUC2 but was compromised in suc2-5. Exogenous Suc also increased root β-glucuronidase (GUS) activity in auxin-inducible reporter DR5-GUS transgenic plants under Fe deficiency. However, exogenous Suc failed to increase FCR activity and expression of Fe acquisition-related genes in the auxin transport-impaired mutants aux1-7 and pin1-1 as well as in the wild-type plants treated with an auxin transport inhibitor under Fe deficiency. In summary, we found that increased Suc accumulation is required for regulating Fe deficiency responses in plants, with auxins acting downstream in transmitting the Fe deficiency signal. PMID:26644507

  13. Moderate increases in intracellular calcium activate neuroprotective signals in hippocampal neurons.

    PubMed

    Bickler, P E; Fahlman, C S

    2004-01-01

    Although large increases in neuronal intracellular calcium concentrations ([Ca(2+)](i)) are lethal, moderate increases in [Ca(2+)](i) of 50-200 nM may induce immediate or long-term tolerance of ischemia or other stresses. In neurons in rat hippocampal slice cultures, we determined the relationship between [Ca(2+)](i), cell death, and Ca(2+)-dependent neuroprotective signals before and after a 45 min period of oxygen and glucose deprivation (OGD). Thirty minutes before OGD, [Ca(2+)](i) was increased in CA1 neurons by 40-200 nM with 1 nM-1 microM of a Ca(2+)-selective ionophore (calcimycin or ionomycin-"Ca(2+) preconditioning"). Ca(2+) preconditioning greatly reduced cell death in CA1, CA3 and dentate during the following 7 days, even though [Ca(2+)](i) was similar (approximately 2 microM) in preconditioned and control neurons 1 h after the OGD. When pre-OGD [Ca(2+)](i) was lowered to 25 nM (10 nM ionophore in Ca(2+)-free medium) or increased to 8 microM (10 microM ionophore), more than 90% of neurons died. Increased levels of the anti-apoptotic protein protein kinase B (Akt) and the MAP kinase ERK (p42/44) were present in preconditioned slices after OGD. Reducing Ca(2+) influx, inhibiting calmodulin, and preventing Akt or MAP kinase p42/44 upregulation prevented Ca(2+) preconditioning, supporting a specific role for Ca(2+) in the neuroprotective process. Further, in continuously oxygenated cultured hippocampal/cortical neurons, preconditioning for 30 min with 10 nM ionomycin reduced cell death following a 4 microM increase in [Ca(2+)](i) elicited by 1 microM ionomycin. Thus, a zone of moderately increased [Ca(2+)](i) before a potentially lethal insult promotes cell survival, uncoupling subsequent large increases in [Ca(2+)](i) from initiating cell death processes.

  14. Is secondary lymphoid-organ chemokine (SLC/CCL21) much more than a constitutive chemokine?

    PubMed

    Serra, H M; Baena-Cagnani, C E; Eberhard, Y

    2004-11-01

    Chemokines are a superfamily of small cytokines with activities ranging from leukocyte traffick to hematopoiesis, angiogenesis, and tissue organogenesis. Secondary lymphoid-organ chemokine (SLC/CCL21) was originally reported as a chemokine constitutively expressed by stromal cells and high endothelial venules in secondary lymphoid tissues and endothelium of afferent lymphatics, directing CCR7+ cells. More recently, others and we have demonstrated that SLC/CCL21 is up-regulated in different skin inflammatory conditions. Thereafter, this molecule is much more than a constitutive chemokine, which could play a role in effector and regulatory immune functions.

  15. Neuronal Chemokines: Versatile Messengers In Central Nervous System Cell Interaction

    PubMed Central

    de Haas, A. H.; van Weering, H. R. J.; de Jong, E. K.; Boddeke, H. W. G. M.

    2007-01-01

    Whereas chemokines are well known for their ability to induce cell migration, only recently it became evident that chemokines also control a variety of other cell functions and are versatile messengers in the interaction between a diversity of cell types. In the central nervous system (CNS), chemokines are generally found under both physiological and pathological conditions. Whereas many reports describe chemokine expression in astrocytes and microglia and their role in the migration of leukocytes into the CNS, only few studies describe chemokine expression in neurons. Nevertheless, the expression of neuronal chemokines and the corresponding chemokine receptors in CNS cells under physiological and pathological conditions indicates that neuronal chemokines contribute to CNS cell interaction. In this study, we review recent studies describing neuronal chemokine expression and discuss potential roles of neuronal chemokines in neuron–astrocyte, neuron–microglia, and neuron–neuron interaction. PMID:17952658

  16. Exendin-4 Inhibits Hepatic Lipogenesis by Increasing β-Catenin Signaling

    PubMed Central

    Hong, Seok-Woo; Rhee, Eun-Jung; Park, Se Eun; Park, Cheol Young; Oh, Ki Won; Park, Sung Woo; Lee, Won-Young

    2016-01-01

    The aim of this study is to investigate whether the beneficial effect of exendin-4 on hepatic steatosis is mediated by β-catenin signaling. After the HepG2 human hepatoma cells were treated with PA for 24 hours, total triglycerides levels were increased in a dose-dependent manner, and the expression levels of perilipin family members were upregulated in cells treated with 400 μM PA. For our in vitro model of hepatic steatosis, HepG2 cells were treated with 400 μM palmitic acid (PA) in the presence or absence of 100 nM exendin-4 for 24 hours. PA increased the expression of lipogenic genes, such as sterol regulatory element-binding protein 1c (SREBP-1c), peroxisome proliferator-activated receptor gamma (PPARγ), stearoyl-CoA desaturase 1 (SCD1), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC) and triglyceride synthesis-involved genes, such as diacylglycerol acyltransferase 1 (DGAT1) and diacylglycerol acyltransferase 2 (DGAT2) in HepG2 cells, whereas exendin-4 treatment significantly prevented the upregulation of SREBP-1c, PPARγ, SCD1, FAS, ACC, DGAT1 and DGAT2. Moreover, exendin-4 treatment increased the expression of phosphorylated glycogen synthase kinase-3 beta (GSK-3β) in the cytosolic fraction and the expression of β-catenin and transcription factor 4 (TCF4) in the nuclear fraction. In addition, siRNA-mediated inhibition of β-catenin upregulated the expression of lipogenic transcription factors. The protective effects of exendin-4 on intracellular triglyceride content and total triglyceride levels were not observed in cells treated with the β-catenin inhibitor IWR-1. These data suggest that exendin-4 treatment improves hepatic steatosis by inhibiting lipogenesis via activation of Wnt/β-catenin signaling. PMID:27907035

  17. Angiotensin II type 1a receptor signalling directly contributes to the increased arrhythmogenicity in cardiac hypertrophy

    PubMed Central

    Yasuno, Shinji; Kuwahara, Koichiro; Kinoshita, Hideyuki; Yamada, Chinatsu; Nakagawa, Yasuaki; Usami, Satoru; Kuwabara, Yoshihiro; Ueshima, Kenji; Harada, Masaki; Nishikimi, Toshio; Nakao, Kazuwa

    2013-01-01

    BACKGROUND AND PURPOSE Angiotensin II has been implicated in the development of various cardiovascular ailments, including cardiac hypertrophy and heart failure. The fact that inhibiting its signalling reduced the incidences of both sudden cardiac death and heart failure in several large-scale clinical trials suggests that angiotensin II is involved in increased cardiac arrhythmogenicity during the development of heart failure. However, because angiotensin II also promotes structural remodelling, including cardiomyocyte hypertrophy and cardiac fibrosis, it has been difficult to assess its direct contribution to cardiac arrhythmogenicity independently of the structural effects. EXPERIMENTAL APPROACH We induced cardiac hypertrophy in wild-type (WT) and angiotensin II type 1a receptor knockout (AT1aR-KO) mice by transverse aortic constriction (TAC). The susceptibility to ventricular tachycardia (VT) assessed in an in vivo electrophysiological study was compared in the two genotypes. The effect of acute pharmacological blockade of AT1R on the incidences of arrhythmias was also assessed. KEY RESULTS As described previously, WT and AT1aR-KO mice with TAC developed cardiac hypertrophy to the same degree, but the incidence of VT was much lower in the latter. Moreover, although TAC induced an increase in tyrosine phosphorylation of connexin 43, a critical component of gap junctional channels, and a reduction in ventricular levels of connexin 43 protein in both genotypes, the effect was significantly ameliorated in AT1aR-KO mice. Acute pharmacological blockade of AT1R also reduced the incidence of arrhythmias. CONCLUSIONS AND IMPLICATIONS Our findings demonstrate that AT1aR-mediated signalling makes a direct contribution to the increase in arrhythmogenicity in hypertrophied hearts independently of structural remodelling. PMID:23937445

  18. Increase in reactive oxygen species and activation of Akt signaling pathway in neuropathic pain.

    PubMed

    Guedes, Renata P; Araújo, Alex S R; Janner, Daiane; Belló-Klein, Adriane; Ribeiro, Maria Flávia M; Partata, Wania A

    2008-12-01

    Neuropathic pain occurs as a result of peripheral or central nervous system injury. Its pathophysiology involves mainly a central sensitization mechanism that may be correlated to many molecules acting in regions involved in pain processing, such as the spinal cord. It has been demonstrated that reactive oxygen species (ROS) and signaling molecules, such as the serine/threonine protein kinase Akt, are involved in neuropathic pain mechanisms. Thus, the aim of this study was to provide evidence of this relationship. Sciatic nerve transection (SNT) was used to induce neuropathic pain in rats. Western blot analysis of Akt and 4-hydroxy-2-nonenal (HNE)-Michael adducts, and measurement of hydrogen peroxide (H(2)O(2)) in the lumbosacral spinal cord were performed. The main findings were found seven days after SNT, when there was an increase in HNE-Michael adducts formation, total and p-Akt expression, and H(2)O(2) concentration. However, one and 15 days after SNT, H(2)O(2) concentration was raised in both sham (animals that were submitted to surgery without nerve injury) and SNT groups, showing the high sensibility of this ROS to nociceptive afferent stimuli, not only to neuropathic pain. p-Akt also increased in sham and SNT groups one day post injury, but at 3 and 7 days the increase occurred exclusively in SNT animals. Thus, there is crosstalk between intracellular signaling pathways and ROS, and these molecules can act as protective agents in acute pain situations or play a role in the development of chronic pain states.

  19. Increased ghrelin signaling prolongs survival in mouse models of human aging through activation of sirtuin1

    PubMed Central

    Fujitsuka, N; Asakawa, A; Morinaga, A; Amitani, M S; Amitani, H; Katsuura, G; Sawada, Y; Sudo, Y; Uezono, Y; Mochiki, E; Sakata, I; Sakai, T; Hanazaki, K; Yada, T; Yakabi, K; Sakuma, E; Ueki, T; Niijima, A; Nakagawa, K; Okubo, N; Takeda, H; Asaka, M; Inui, A

    2016-01-01

    Caloric restriction (CR) is known to retard aging and delay functional decline as well as the onset of diseases in most organisms. Ghrelin is secreted from the stomach in response to CR and regulates energy metabolism. We hypothesized that in CR ghrelin has a role in protecting aging-related diseases. We examined the physiological mechanisms underlying the ghrelin system during the aging process in three mouse strains with different genetic and biochemical backgrounds as animal models of accelerated or normal human aging. The elevated plasma ghrelin concentration was observed in both klotho-deficient and senescence-accelerated mouse prone/8 (SAMP8) mice. Ghrelin treatment failed to stimulate appetite and prolong survival in klotho-deficient mice, suggesting the existence of ghrelin resistance in the process of aging. However, ghrelin antagonist hastened death and ghrelin signaling potentiators rikkunshito and atractylodin ameliorated several age-related diseases with decreased microglial activation in the brain and prolonged survival in klotho-deficient, SAMP8 and aged ICR mice. In vitro experiments, the elevated sirtuin1 (SIRT1) activity and protein expression through the cAMP–CREB pathway was observed after ghrelin and ghrelin potentiator treatment in ghrelin receptor 1a-expressing cells and human umbilical vein endothelial cells. Furthermore, rikkunshito increased hypothalamic SIRT1 activity and SIRT1 protein expression of the heart in the all three mouse models of aging. Pericarditis, myocardial calcification and atrophy of myocardial and muscle fiber were improved by treatment with rikkunshito. Ghrelin signaling may represent one of the mechanisms activated by CR, and potentiating ghrelin signaling may be useful to extend health and lifespan. PMID:26830139

  20. Borrelia burgdorferi induces chemokines in human monocytes.

    PubMed Central

    Sprenger, H; Krause, A; Kaufmann, A; Priem, S; Fabian, D; Burmester, G R; Gemsa, D; Rittig, M G

    1997-01-01

    Lyme disease is clinically and histologically characterized by strong inflammatory reactions that contrast the paucity of spirochetes at lesional sites, indicating that borreliae induce mechanisms that amplify the inflammatory response. To reveal the underlying mechanisms of chemoattraction and activation of responding leukocytes, we investigated the induction of chemokines in human monocytes exposed to Borrelia burgdorferi by a dose-response and kinetic analysis. Lipopolysaccharide (LPS) derived from Escherichia coli was used as a positive control stimulus. The release of the CXC chemokines interleukin-8 (IL-8) and GRO-alpha and the CC chemokines MIP-1alpha, MCP-1, and RANTES was determined by specific enzyme-linked immunosorbent assays, and the corresponding gene expression patterns were determined by Northern blot analysis. The results showed a rapid and strong borrelia-inducible gene expression which was followed by the release of chemokines with peak levels after 12 to 16 h. Spirochetes and LPS were comparably effective in stimulating IL-8, GRO-alpha, MCP-1, and RANTES expression, whereas MIP-1alpha production preceded and exceeded chemokine levels induced by LPS. Unlike other bacteria, the spirochetes themselves did not bear or release factors with intrinsic chemotactic activity for monocytes or neutrophils. Thus, B. burgdorferi appears to be a strong inducer of chemokines which may, by the attraction and activation of phagocytic leukocytes, significantly contribute to inflammation and tissue damage observed in Lyme disease. PMID:9353009

  1. Chemokine and cytokine levels in inflammatory bowel disease patients.

    PubMed

    Singh, Udai P; Singh, Narendra P; Murphy, E Angela; Price, Robert L; Fayad, Raja; Nagarkatti, Mitzi; Nagarkatti, Prakash S

    2016-01-01

    Crohn's disease (CD) and ulcerative colitis (UC), two forms of inflammatory bowel disease (IBD), are chronic, relapsing, and tissue destructive lesions that are accompanied by the uncontrolled activation of effector immune cells in the mucosa. Recent estimates indicate that there are 1.3 million annual cases of IBD in the United States, 50% of which consists of CD and 50% of UC. Chemokines and cytokines play a pivotal role in the regulation of mucosal inflammation by promoting leukocyte migration to sites of inflammation ultimately leading to tissue damage and destruction. In recent years, experimental studies in rodents have led to a better understanding of the role played by these inflammatory mediators in the development and progression of colitis. However, the clinical literature on IBD remains limited. Therefore, the aim of this study was to evaluate systemic concentrations of key chemokines and cytokines in forty-two IBD patients with a range of disease activity compared to levels found in ten healthy donors. We found a significant increase in an array of chemokines including macrophage migration factor (MIF), CCL25, CCL23, CXCL5, CXCL13, CXCL10, CXCL11, MCP1, and CCL21 in IBD patients as compared to normal healthy donors (P<0.05). Further, we also report increases in the inflammatory cytokines IL-16, IFN-γ, IL-1β and TNF-α in IBD patients when compared to healthy donors (P<0.05). These data clearly indicate an increase in circulating levels of specific chemokines and cytokines that are known to modulate systemic level through immune cells results in affecting local intestinal inflammation and tissue damage in IBD patients. Blockade of these inflammatory mediators should be explored as a mechanism to alleviate or even reverse symptoms of IBD.

  2. Gs-coupled GPCR signalling in AgRP neurons triggers sustained increase in food intake

    PubMed Central

    Nakajima, Ken-ichiro; Cui, Zhenzhong; Li, Chia; Meister, Jaroslawna; Cui, Yinghong; Fu, Ou; Smith, Adam S.; Jain, Shalini; Lowell, Bradford B.; Krashes, Michael J.; Wess, Jürgen

    2016-01-01

    Agouti-related peptide (AgRP) neurons of the hypothalamus play a key role in regulating food intake and body weight, by releasing three different orexigenic molecules: AgRP; GABA; and neuropeptide Y. AgRP neurons express various G protein-coupled receptors (GPCRs) with different coupling properties, including Gs-linked GPCRs. At present, the potential role of Gs-coupled GPCRs in regulating the activity of AgRP neurons remains unknown. Here we show that the activation of Gs-coupled receptors expressed by AgRP neurons leads to a robust and sustained increase in food intake. We also provide detailed mechanistic data linking the stimulation of this class of receptors to the observed feeding phenotype. Moreover, we show that this pathway is clearly distinct from other GPCR signalling cascades that are operative in AgRP neurons. Our data suggest that drugs able to inhibit this signalling pathway may become useful for the treatment of obesity. PMID:26743492

  3. Kaempferol Isolated from Nelumbo nucifera Inhibits Lipid Accumulation and Increases Fatty Acid Oxidation Signaling in Adipocytes.

    PubMed

    Lee, Bonggi; Kwon, Misung; Choi, Jae Sue; Jeong, Hyoung Oh; Chung, Hae Young; Kim, Hyeung-Rak

    2015-12-01

    Stamens of Nelumbo nucifera Gaertn have been used as a Chinese medicine due to its antioxidant, hypoglycemic, and antiatherogenic activity. However, the effects of kaempferol, a main component of N. nucifera, on obesity are not fully understood. We examined the effect of kaempferol on adipogenesis and fatty acid oxidation signaling pathways in 3T3-L1 adipocytes. Kaempferol reduced cytoplasmic triglyceride (TG) accumulation in dose and time-dependent manners during adipocyte differentiation. Accumulation of TG was rapidly reversed by retrieving kaempferol treatment. Kaempferol broadly decreased mRNA or protein levels of adipogenic transcription factors and their target genes related to lipid accumulation. Kaempferol also suppressed glucose uptake and glucose transporter GLUT4 mRNA expression in adipocytes. Furthermore, protein docking simulation suggests that Kaempferol can directly bind to and activate peroxisome proliferator-activated receptor (PPAR)-α by forming hydrophobic interactions with VAL324, THR279, and LEU321 residues of PPARα. The binding affinity was higher than a well-known PPARα agonist fenofibrate. Consistently, mRNA expression levels of PPARα target genes were increased. Our study indicates while kaempferol inhibits lipogenic transcription factors and lipid accumulation, it may bind to PPARα and stimulate fatty acid oxidation signaling in adipocytes.

  4. VCC-1, a novel chemokine, promotes tumor growth

    SciTech Connect

    Weinstein, Edward J.; Head, Richard; Griggs, David W.; Sun Duo; Evans, Robert J.; Swearingen, Michelle L.; Westlin, Marisa M.; Mazzarella, Richard . E-mail: richard.a.mazzarella@pfizer.com

    2006-11-10

    We have identified a novel human gene by transcriptional microarray analysis, which is co-regulated in tumors and angiogenesis model systems with VEGF expression. Isolation of cDNA clones containing the full-length VCC-1 transcript from both human and mouse shows a 119 amino acid protein with a 22 amino acid cleavable signal sequence in both species. Comparison of the protein product of this gene with hidden Markov models of all known proteins shows weak but significant homology with two known chemokines, SCYA17 and SCYA16. Northern analysis of human tissues detects a 1 kb band in lung and skeletal muscle. Murine VCC-1 expression can also be detected in lung as well as thyroid, submaxillary gland, epididymis, and uterus tissues by slot blot analysis. By quantitative real time RT-PCR 71% of breast tumors showed 3- to 24-fold up-regulation of VCC-1. In situ hybridization of breast carcinomas showed strong expression of the gene in both normal and transformed mammary gland ductal epithelial cells. In vitro, human microvascular endothelial cells grown on fibronectin increase VCC-1 expression by almost 100-fold. In addition, in the mouse angioma endothelial cell line PY4.1 the gene was over-expressed by 28-fold 6 h after induction of tube formation while quiescent and proliferating cells showed no change. VCC-1 expression is also increased by VEGF and FGF treatment, about 6- and 5-fold, respectively. Finally, 100% of mice injected with NIH3T3 cells over-expressing VCC-1 develop rapidly progressing tumors within 21 days while no growth is seen in any control mice injected with NIH3T3 cells containing the vector alone. These results strongly suggest that VCC-1 plays a role in angiogenesis and possibly in the development of tumors in some tissue types.

  5. Structural And Functional Characterization of CC Chemokine CCL14

    SciTech Connect

    Blain, K.Y.; Kwiatkowski, W.; Zhao, Q.; Fleur, D.La; Naik, C.; Chun, T.-W.; Tsareva, T.; Kanakaraj, P.; Laird, M.W.; Shah, R.; George, L.; Sanyal, I.; Moore, P.A.; Demeler, B.; Choe, S.

    2009-06-02

    CC chemokine ligand 14, CCL14, is a human CC chemokine that is of recent interest because of its natural ability, upon proteolytic processing of the first eight NH{sub 2}-terminal residues, to bind to and signal through the human immunodeficiency virus type-1 (HIV-1) co-receptor, CC chemokine receptor 5 (CCR5). We report X-ray crystallographic structures of both full-length CCL14 and signaling-active, truncated CCL14 [9-74] determined at 2.23 and 1.8 {angstrom}, respectively. Although CCL14 and CCL14 [9-74] differ in their ability to bind CCR5 for biological signaling, we find that the NH{sub 2}-terminal eight amino acids (residues 1 through 8) are completely disordered in CCL14 and both show the identical mode of the dimeric assembly characteristic of the CC type chemokine structures. However, analytical ultracentrifugation studies reveal that the CCL14 is stable as a dimer at a concentration as low as 100 nM, whereas CCL14 [9-74] is fully monomeric at the same concentration. By the same method, the equilibrium between monomers of CCL14 [9-74] and higher order oligomers is estimated to be of EC{sub 1,4} = 4.98 {mu}M for monomer-tetramer conversion. The relative instability of CCL14 [9-74] oligomers as compared to CCL14 is also reflected in the K{sub d}'s that are estimated by the surface plasmon resonance method to be {approx}9.84 and 667 nM for CCL14 and CCL14 [9-74], respectively. This {approx}60-fold difference in stability at a physiologically relevant concentration can potentially account for their different signaling ability. Functional data from the activity assays by intracellular calcium flux and inhibition of CCR5-mediated HIV-1 entry show that only CCL14 [9-74] is fully active at these near-physiological concentrations where CCL14 [9-74] is monomeric and CCL14 is dimeric. These results together suggest that the ability of CCL14 [9-74] to monomerize can play a role for cellular activation.

  6. Anti-infective peptide IDR-1002 augments monocyte chemotaxis towards CCR5 chemokines.

    PubMed

    Madera, Laurence; Hancock, Robert E W

    2015-08-28

    Innate defense regulator (IDR) peptides are a class of immunomodulators which enhance and modulate host innate immune responses against microbial pathogens. While IDR-mediated protection against a range of bacterial pathogens is dependent on enhanced monocyte recruitment to the site of infection, the mechanisms through which they increase monocyte trafficking remain unclear. In this study, anti-infective peptide IDR-1002 was shown to enhance monocyte chemotaxis towards chemokines CCL3 and CCL5. This enhancement correlated with the selective upregulation of CCR5 surface expression by peptide-treated monocytes. It was found that IDR-1002 enhancement of monocyte chemotaxis was fully dependent on CCR5 function. Furthermore, IDR-1002 enhanced chemokine-induced monocyte p38 MAPK phosphorylation in a CCR5-dependent fashion. Overall, these results indicate that peptide IDR-1002 can selectively influence monocyte recruitment by host chemokines through the regulation of chemokine receptors.

  7. Bivalent Ligands Targeting Chemokine Receptor Dimerization: Molecular Design and Functional Studies

    PubMed Central

    Arnatt, Christopher Kent; Zhang, Yan

    2015-01-01

    Increasing evidence has shown that chemokine receptors may form functional dimers with unique pharmacological profiles. A common practice to characterize such G protein-coupled receptor dimerization processes is to apply bivalent ligands as chemical probes which can interact with both receptors simultaneously. Currently, two chemokine receptor dimers have been studied by applying bivalent compounds: the CXCR4-CXCR4 homodimer and the CCR5-MOR heterodimer. These bivalent compounds have revealed how dimerization influences receptor function and may lead to novel therapeutics. Future design of bivalent ligands for chemokine receptor dimers may be aided with the recently available CXCR4 homodimer, and CCR5 monomer crystal structures by more accurately simulating chemokine receptors and their dimers. PMID:25159160

  8. Pathogen-induced chemokine secretion from model intestinal epithelium is inhibited by lipoxin A4 analogs.

    PubMed Central

    Gewirtz, A T; McCormick, B; Neish, A S; Petasis, N A; Gronert, K; Serhan, C N; Madara, J L

    1998-01-01

    Enteric pathogens induce intestinal epithelium to secrete chemokines that direct movement of polymorphonuclear leukocytes. Mechanisms that might downregulate secretion of these proinflammatory chemokines and thus contain intestinal inflammation have not yet been elucidated. The antiinflammatory activities exhibited by the arachidonate metabolite lipoxin A4 (LXA4) suggests that this eicosanoid, which is biosynthesized in vivo at sites of inflammation, might play such a role. We investigated whether chemokine secretion could be regulated by stable analogs of LXA4. Monolayers of T84 intestinal epithelial cells were infected with Salmonella typhimurium, which elicits secretion of distinct apical (pathogen-elicited epithelial chemoattractant) and basolateral (IL-8) chemokines. Stable analogs of LXA4 inhibited S. typhimurium-induced (but not phorbol ester-induced) secretion of both IL-8 and pathogen-elicited epithelial chemoattractant. LXA4 stable analogs did not alter bacterial adherence to nor internalization by epithelia, indicating that LXA4 stable analogs did not block all signals that Salmonella typhimurium activates in intestinal epithelia, but likely led to attenuation of signals that mediate chemokine secretion. Inhibition of S. typhimurium-induced IL-8 secretion by LXA4 analogs was concentration- (IC50 approximately 1 nM) and time-dependent (maximal inhibition approximately 1 h). As a result of these effects, LXA4 stable analogs inhibited the ability of bacteria-infected epithelia to direct polymorphonuclear leukocyte movement. These data suggest that LXA4 and its stable analogs may be useful in downregulating active inflammation at mucosal surfaces. PMID:9576749

  9. Increased hypothalamic GPR54 signaling: a potential mechanism for initiation of puberty in primates.

    PubMed

    Shahab, Muhammad; Mastronardi, Claudio; Seminara, Stephanie B; Crowley, William F; Ojeda, Sergio R; Plant, Tony M

    2005-02-08

    To further study the role of GPR54 signaling in the onset of primate puberty, we used the monkey to examine the ability of kisspeptin-10 to elicit the release of gonadotropin-releasing hormone (GnRH) precociously, and we describe the expression of GPR54 and KiSS-1 in the hypothalamus during the peripubertal period. Agonadal juvenile male monkeys were implanted with a lateral cerebroventricular cannula and a jugular vein catheter. The responsiveness of the juvenile pituitary to endogenous GnRH release was heightened with a chronic pulsatile i.v. infusion of synthetic GnRH before kisspeptin-10 (112-121) injection. Intracerebroventricular (30 microg or 100 microg) or i.v. (100 microg) bolus injections of kisspeptin-10 elicited a robust GnRH discharge, as reflected by luteinizing hormone secretion, which was abolished by pretreatment with a GnRH-receptor antagonist. RNA was isolated from the hypothalamus of agonadal males before (juvenile) and after (pubertal) the pubertal resurgence of pulsatile GnRH release and from juvenile, early pubertal, and midpubertal ovary-intact females. KiSS-1 mRNA levels detected by real-time PCR increased with puberty in both male and female monkeys. In intact females, but not in agonadal males, GPR54 mRNA levels in the hypothalamus increased approximately 3-fold from the juvenile to midpubertal stage. Hybridization histochemistry indicated robust KiSS-1 and GPR54 mRNA expression in the region of the arcuate nucleus. These findings are consistent with the hypothesis that GPR54 signaling by its cognate ligand in the primate hypothalamus may be activated at the end of the juvenile phase of development and may contribute to the pubertal resurgence of pulsatile GnRH release, the central drive for puberty.

  10. Increasing signal processing sophistication in the calculation of the respiratory modulation of the photoplethysmogram (DPOP).

    PubMed

    Addison, Paul S; Wang, Rui; Uribe, Alberto A; Bergese, Sergio D

    2015-06-01

    DPOP (∆POP or Delta-POP) is a non-invasive parameter which measures the strength of respiratory modulations present in the pulse oximetry photoplethysmogram (pleth) waveform. It has been proposed as a non-invasive surrogate parameter for pulse pressure variation (PPV) used in the prediction of the response to volume expansion in hypovolemic patients. Many groups have reported on the DPOP parameter and its correlation with PPV using various semi-automated algorithmic implementations. The study reported here demonstrates the performance gains made by adding increasingly sophisticated signal processing components to a fully automated DPOP algorithm. A DPOP algorithm was coded and its performance systematically enhanced through a series of code module alterations and additions. Each algorithm iteration was tested on data from 20 mechanically ventilated OR patients. Correlation coefficients and ROC curve statistics were computed at each stage. For the purposes of the analysis we split the data into a manually selected 'stable' region subset of the data containing relatively noise free segments and a 'global' set incorporating the whole data record. Performance gains were measured in terms of correlation against PPV measurements in OR patients undergoing controlled mechanical ventilation. Through increasingly advanced pre-processing and post-processing enhancements to the algorithm, the correlation coefficient between DPOP and PPV improved from a baseline value of R = 0.347 to R = 0.852 for the stable data set, and, correspondingly, R = 0.225 to R = 0.728 for the more challenging global data set. Marked gains in algorithm performance are achievable for manually selected stable regions of the signals using relatively simple algorithm enhancements. Significant additional algorithm enhancements, including a correction for low perfusion values, were required before similar gains were realised for the more challenging global data set.

  11. Melanocortin 3 Receptor Signaling in Midbrain Dopamine Neurons Increases the Motivation for Food Reward.

    PubMed

    Pandit, Rahul; Omrani, Azar; Luijendijk, Mieneke C M; de Vrind, Véronne A J; Van Rozen, Andrea J; Ophuis, Ralph J A Oude; Garner, Keith; Kallo, Imre; Ghanem, Alexander; Liposits, Zsolt; Conzelmann, Karl-Klaus; Vanderschuren, Louk J M J; la Fleur, Susanne E; Adan, Roger A H

    2016-08-01

    The central melanocortin (MC) system mediates its effects on food intake via MC3 (MC3R) and MC4 receptors (MC4R). Although the role of MC4R in meal size determination, satiation, food preference, and motivation is well established, the involvement of MC3R in the modulation of food intake has been less explored. Here, we investigated the role of MC3R on the incentive motivation for food, which is a crucial component of feeding behavior. Dopaminergic neurons within the ventral tegmental area (VTA) have a crucial role in the motivation for food. We here report that MC3Rs are expressed on VTA dopaminergic neurons and that pro-opiomelanocortinergic (POMC) neurons in the arcuate nucleus of the hypothalamus (Arc) innervate these VTA dopaminergic neurons. Our findings show that intracerebroventricular or intra-VTA infusion of the selective MC3R agonist γMSH increases responding for sucrose under a progressive ratio schedule of reinforcement, but not free sucrose consumption in rats. Furthermore, ex vivo electrophysiological recordings show increased VTA dopaminergic neuronal activity upon γMSH application. Consistent with a dopamine-mediated effect of γMSH, the increased motivation for sucrose after intra-VTA infusion of γMSH was blocked by pretreatment with the dopamine receptor antagonist α-flupenthixol. Taken together, we demonstrate an Arc POMC projection onto VTA dopaminergic neurons that modulates motivation for palatable food via activation of MC3R signaling.

  12. ANGPTL2 increases bone metastasis of breast cancer cells through enhancing CXCR4 signaling.

    PubMed

    Masuda, Tetsuro; Endo, Motoyoshi; Yamamoto, Yutaka; Odagiri, Haruki; Kadomatsu, Tsuyoshi; Nakamura, Takayuki; Tanoue, Hironori; Ito, Hitoshi; Yugami, Masaki; Miyata, Keishi; Morinaga, Jun; Horiguchi, Haruki; Motokawa, Ikuyo; Terada, Kazutoyo; Morioka, Masaki Suimye; Manabe, Ichiro; Iwase, Hirotaka; Mizuta, Hiroshi; Oike, Yuichi

    2015-03-16

    Bone metastasis of breast cancer cells is a major concern, as it causes increased morbidity and mortality in patients. Bone tissue-derived CXCL12 preferentially recruits breast cancer cells expressing CXCR4 to bone metastatic sites. Thus, understanding how CXCR4 expression is regulated in breast cancer cells could suggest approaches to decrease bone metastasis of breast tumor cells. Here, we show that tumor cell-derived angiopoietin-like protein 2 (ANGPTL2) increases responsiveness of breast cancer cells to CXCL12 by promoting up-regulation of CXCR4 in those cells. In addition, we used a xenograft mouse model established by intracardiac injection of tumor cells to show that ANGPTL2 knockdown in breast cancer cells attenuates tumor cell responsiveness to CXCL12 by decreasing CXCR4 expression in those cells, thereby decreasing bone metastasis. Finally, we found that ANGPTL2 and CXCR4 expression levels within primary tumor tissues from breast cancer patients are positively correlated. We conclude that tumor cell-derived ANGPTL2 may increase bone metastasis by enhancing breast tumor cell responsiveness to CXCL12 signaling through up-regulation of tumor cell CXCR4 expression. These findings may suggest novel therapeutic approaches to treat metastatic breast cancer.

  13. Induction of cytokine granulocyte-macrophage colony-stimulating factor and chemokine macrophage inflammatory protein 2 mRNAs in macrophages by Legionella pneumophila or Salmonella typhimurium attachment requires different ligand-receptor systems.

    PubMed Central

    Yamamoto, Y; Klein, T W; Friedman, H

    1996-01-01

    The attachment of bacteria to macrophages is mediated by different ligands and receptors and induces various intracellular molecular responses. In the present study, induction of cytokines and chemokines, especially granulocyte-macrophage colony-stimulating factor (GM-CSF) and macrophage inflammatory protein 2 (MIP-2), was examined, following bacterial attachment, with regard to the ligand-receptor systems involved. Attachment of Legionella pneumophila or Salmonella typhimurium to cultured mouse peritoneal macrophages increased the steady-state levels of cellular mRNAs for the cytokines interleukin 1beta (IL-1beta), IL-6, and GM-CSF as well as the chemokines MIP-1beta, MIP-2, and KC. However, when macrophages were treated with alpha-methyl-D-mannoside (alphaMM), a competitor of glycopeptide ligands, induction of cytokine mRNAs was inhibited, but the levels of chemokine mRNAs were not. Pretreatment of the bacteria with fresh mouse serum enhanced the level of GM-CSF mRNA but not the level of MIP-2 mRNA. In addition, serum treatment reduced the inhibitory effect of alphaMM on GM-CSF mRNA. These results indicate that bacterial attachment increases the steady-state levels of the cytokine and chemokine mRNAs tested by at least two distinct receptor-ligand systems, namely, one linked to cytokine induction and involving mannose or other sugar residues and the other linked to chemokine induction and relatively alphaMM insensitive. Furthermore, opsonization with serum engages other pathways in the cytokine response which are relatively independent of the alphaMM-sensitive system. Regarding bacterial surface ligands involved in cytokine mRNA induction, evidence is presented that the flagellum may be important in stimulating cytokine GM-CSF message but not chemokine MIP-2 message. Analysis of cytokine GM-CSF and chemokine MIP-2 signaling pathways with protein kinase inhibitors revealed the involvement of calmodulin and myosin light-chain kinase in GM-CSF but not MIP-2 m

  14. Increases in Retrograde Injury Signaling Complex-Related Transcripts in Central Axons following Injury

    PubMed Central

    Pathak, Gunja K.; Ornstein, Hannah; Aranda-Espinoza, Helim; Karlsson, Amy J.

    2016-01-01

    Axons in the peripheral nervous system respond to injury by activating retrograde injury signaling (RIS) pathways, which promote local axonal protein synthesis (LPS) and neuronal regeneration. RIS is also initiated following injury of neurons in the central nervous system (CNS). However, regulation of the localization of axonal mRNA required for LPS is not well understood. We used a hippocampal explant system to probe the regulation of axonal levels of RIS-associated transcripts following axonal injury. Axonal levels of importin β1 and RanBP1 were elevated biphasically at 1 and 24 hrs after axotomy. Transcript levels for β-actin, a prototypic axonally synthesized protein, were similarly elevated. Our data suggest differential regulation of axonal transcripts. At 1 hr after injury, deployment of actinomycin revealed that RanBP1, but not importin β1, requires de novo mRNA synthesis. At 24 hrs after injury, use of importazole revealed that the second wave of increased axonal mRNA levels required importin β-mediated nuclear import. We also observed increased importin β1 axonal protein levels at 1 and 6 hrs after injury. RanBP1 levels and vimentin levels fluctuated but were unchanged at 3 and 6 hrs after injury. This study revealed temporally complex regulation of axonal transcript levels, and it has implications for understanding neuronal response to injury in the CNS. PMID:27847648

  15. Vision of the body increases interference on the somatic signal detection task.

    PubMed

    Mirams, Laura; Poliakoff, Ellen; Brown, Richard J; Lloyd, Donna M

    2010-05-01

    Research suggests that attention has a significant effect on somatic perception in both healthy people and those who suffer from somatic disturbance. The current study investigates the effects of attending to the body on somatic awareness and a particular type of somatic disturbance: erroneous reports of touch sensation, as measured by the Somatic Signal Detection Task (SSDT). During the SSDT, participants are required to detect near-threshold tactile stimulation at their fingertip. Previous research has found that healthy participants erroneously report touch sensations in the absence of a stimulus on this task and that such false alarms are increased when a simultaneous light flash is presented next to their fingertip. Thirty-seven participants completed the SSDT under two conditions: non-informative vision of the hand and no vision of the hand. False alarms were significantly higher in light trials in the non-informative vision condition compared to light trials in the no-vision condition. However, hit rates, sensitivity (d') and response criterion (c) were not affected by non-informative vision of the hand. Using the SSDT, we found that viewing the body increased somatic interference, possibly due to raised awareness of internal bodily sensations. This work provides evidence that viewing the body can have a detrimental effect on simple detection of near-threshold tactile stimulation.

  16. VEGFR-2 reduces while combined VEGFR-2 and -3 signaling increases inflammation in apical periodontitis

    PubMed Central

    Virtej, Anca; Papadakou, Panagiota; Sasaki, Hajime; Bletsa, Athanasia; Berggreen, Ellen

    2016-01-01

    Background In apical periodontitis, oral pathogens provoke an inflammatory response in the apical area that induces bone resorptive lesions. In inflammation, angio- and lymphangiogenesis take place. Vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs) are key players in these processes and are expressed in immune cells and endothelial cells in the lesions. Objective We aimed at testing the role of VEGFR-2 and -3 in periapical lesion development and investigated their role in lymphangiogenesis in the draining lymph nodes. Design We induced lesions by pulp exposure in the lower first molars of C57BL/6 mice. The mice received IgG injections or blocking antibodies against VEGFR-2 (anti-R2), VEGFR-3 (anti-R3), or combined VEGFR-2 and -3, starting on day 0 until day 10 or 21 post-exposure. Results Lesions developed faster in the anti-R2 and anti-R3 group than in the control and anti-R2/R3 groups. In the anti-R2 group, a strong inflammatory response was found expressed as increased number of neutrophils and osteoclasts. A decreased level of pro-inflammatory cytokines was found in the anti-R2/R3 group. Lymphangiogenesis in the draining lymph nodes was inhibited after blocking of VEGFR-2 and/or -3, while the largest lymph node size was seen after anti-R2 treatment. Conclusions We demonstrate an anti-inflammatory effect of VEGFR-2 signaling in periapical lesions which seems to involve neutrophil regulation and is independent of angiogenesis. Combined signaling of VEGFR-2 and -3 has a pro-inflammatory effect. Lymph node lymphangiogenesis is promoted through activation of VEGFR-2 and/or VEGFR-3. PMID:27650043

  17. Inhibition of a novel specific neuroglial integrin signaling pathway increases STAT3-mediated CNTF expression

    PubMed Central

    2013-01-01

    Background Ciliary neurotrophic factor (CNTF) expression is repressed in astrocytes by neuronal contact in the CNS and is rapidly induced by injury. Here, we defined an inhibitory integrin signaling pathway. Results The integrin substrates laminin, fibronectin and vitronectin, but not collagen, thrombospondin or fibrinogen, reduced CNTF expression in C6 astroglioma cells. Antibodies against αv and β5, but not α6 or β1, integrin induced CNTF. Together, the ligand and antibody specificity suggests that CNTF is repressed by αvβ5 integrin. Antibodies against Thy1, an abundant neuronal surface protein whose function is unclear, induced CNTF in neuron-astrocyte co-cultures indicating that it is a neuroglial CNTF repressor. Inhibition of the integrin signaling molecule Focal Adhesion Kinase (FAK) or the downstream c-Jun N-terminal kinase (JNK), but not extracellular regulated kinase (ERK) or p38 MAPK, greatly induced CNTF mRNA and protein expression within 4 hours. This selective inhibitory pathway phosphorylated STAT3 on its inhibitory ser-727 residue interfering with activity of the pro-transcription Tyr-705 residue. STAT3 can activate CNTF transcription because it bound to its promoter and FAK antagonist-induced CNTF was reduced by blocking STAT3. Microinjection of FAK inhibitor directly into the brain or spinal cord in adult mice rapidly induced CNTF mRNA and protein expression. Importantly, systemic treatment with FAK inhibitors over 3 days induced CNTF in the subventricular zone and increased neurogenesis. Conclusions Neuron-astroglia contact mediated by integrins serves as a sensor to enable rapid neurotrophic responses and provides a new pharmacological avenue to exploit the neuroprotective properties of endogenous CNTF. PMID:23693126

  18. Structural Insights into the Interaction Between a Potent Anti-Inflammatory Protein, Viral CC Chemokine Inhibitor (vCCI), and the Human CC Chemokine, Eotaxin-1

    SciTech Connect

    Kuo, Nai-Wei; Gao, Yong; Schill, Megan S.; Isern, Nancy G.; Dupureur, Cynthia M.; Liwang, Patricia J.

    2014-01-30

    Chemokines play important roles in the immune system, not only recruiting leukocytes to the site of infection and inflammation but also guiding cell homing and cell development. The soluble poxvirusencoded protein vCCI, a CC chemokine inhibitor, can bind to human CC chemokines tightly to impair the host immune defense. This protein has no known homologs in eukaryotes, and may represent a potent method to stop inflammation. Previously, our structure of the vCCI:MIP-1β complex indicated that vCCI uses negatively charged residues in β-sheet II to interact with positively charged residues in the MIP-1βN-terminus, 20’s region and 40’s loop. However, the interactions between vCCI and other CC chemokines have not yet been fully explored. Here, we used NMR and fluorescence anisotropy to study the interaction between vCCI and eotaxin-1 (CCL11), another CC chemokine that is an important factor in the asthma response. NMR results reveal that the binding pattern is very similar to the vCCI:MIP-1βcomplex, and suggest that electrostatic interactions provide a major contribution to binding. Fluorescence anisotropy results on variants of eotaxin-1 further confirm the critical roles of the charged residues in eotaxin. Compared to wild-type eotaxin, single, double, or triple mutations at these critical charged residues weaken the binding. One exception is the K47A mutation that exhibits increased affinity for vCCI, which can be explained structurally. In addition, the binding affinity between vCCI and other wild type CC chemokines, MCP-1, MIP-1β and RANTES, were determined as 1.09 nM, 1.16 nM, and 0.22 nM, respectively. To our knowledge, this is the first work quantitatively measuring the binding affinity between vCCI and different CC chemokines.

  19. Significance of chemokine and chemokine receptors in head and neck squamous cell carcinoma: A critical review.

    PubMed

    da Silva, Janine Mayra; Soave, Danilo Figueiredo; Moreira Dos Santos, Tálita Pollyanna; Batista, Aline Carvalho; Russo, Remo Castro; Teixeira, Mauro Martins; da Silva, Tarcília Aparecida

    2016-05-01

    Chemokines are small chemotactic proteins that coordinate circulation of immune/inflammatory cells throughout body compartments. Because of this property chemokines and their cell surface receptors are implicated in several physiological and pathological conditions, including cancer. These molecules are expressed by neoplastic or stromal cells and have effects at tumor primary site (e.g. stimulating angiogenesis and tumor cells motility) and lymph nodes (creating a gradient to direct migration of neoplastic cells). In this article we review the current knowledge about the function(s) of chemokines and receptors in squamous cell carcinoma from the oral cavity and head and neck region. Accumulating evidence suggests some chemokine(s) and receptor(s) as potential targets in adjuvant therapies for these malignancies.

  20. Increased expression of epidermal growth factor receptor induces sequestration of extracellular signal-related kinases and selective attenuation of specific epidermal growth factor-mediated signal transduction pathways.

    PubMed

    Habib, Amyn A; Chun, Soo Jin; Neel, Benjamin G; Vartanian, Timothy

    2003-01-01

    Increased expression of the epidermal growth factor receptor (EGFR) is common in cancer and correlates with neoplastic progression. Although the biology of this receptor has been the subject of intense investigation, surprisingly little is known about how increased expression of the wild-type EGFR affects downstream signal transduction in cells. We show that increasing the expression of the receptor results in dramatic shifts in signaling with attenuation of EGF-induced Ras, extracellular signal-related kinases (ERKs), and Akt activation, as well as amplification of STAT1 and STAT3 signaling. In this study, we focus on the mechanism of attenuated ERK signaling and present evidence suggesting that the mechanism of attenuated ERK signaling in EGFR-overexpressing cells is a sequestration of ERKs at the cell membrane in EGFR-containing complexes. Increased expression of the EGFR results in an aberrant localization of ERKs to the cell membrane. Furthermore, ERKs become associated with the EGFR in a physical complex in EGFR-overexpressing cells but not in control cells. The EGFR-ERK association is detected in unstimulated cells or on exposure to a low concentration of EGF; under these conditions, ERK activation is minimal. Exposure of these cells to saturating concentrations of EGF results in a decreased membrane localization of ERKs, a concomitant dissociation of ERKs from the EGFR, and restores ERK activation. A similar association can be detected between the EGFR and MEK1 in receptor-overexpressing cells, suggesting that multiple components of the ERK signaling pathway may become trapped in complexes with the EGFR. These findings can be demonstrated in cells transfected to express high levels of the EGFR as well as in cancer cells which naturally overexpress the EGFR and, thus, may be representative of altered EGFR signaling in human cancer.

  1. Chemokine Function in Periodontal Disease and Oral Cavity Cancer

    PubMed Central

    Sahingur, Sinem Esra; Yeudall, W. Andrew

    2015-01-01

    The chemotactic cytokines, or chemokines, comprise a superfamily of polypeptides with a wide range of activities that include recruitment of immune cells to sites of infection and inflammation, as well as stimulation of cell proliferation. As such, they function as antimicrobial molecules and play a central role in host defenses against pathogen challenge. However, their ability to recruit leukocytes and potentiate or prolong the inflammatory response may have profound implications for the progression of oral diseases such as chronic periodontitis, where tissue destruction may be widespread. Moreover, it is increasingly recognized that chronic inflammation is a key component of tumor progression. Interaction between cancer cells and their microenvironment is mediated in large part by secreted factors such as chemokines, and serves to enhance the malignant phenotype in oral and other cancers. In this article, we will outline the biological and biochemical mechanisms of chemokine action in host–microbiome interactions in periodontal disease and in oral cancer, and how these may overlap and contribute to pathogenesis. PMID:25999952

  2. CC-chemokine class inhibition attenuates pathological angiogenesis while preserving physiological angiogenesis.

    PubMed

    Ridiandries, Anisyah; Tan, Joanne T M; Ravindran, Dhanya; Williams, Helen; Medbury, Heather J; Lindsay, Laura; Hawkins, Clare; Prosser, Hamish C G; Bursill, Christina A

    2017-03-01

    Increasing evidence shows that CC-chemokines promote inflammatory-driven angiogenesis, with little to no effect on hypoxia-mediated angiogenesis. Inhibition of the CC-chemokine class may therefore affect angiogenesis differently depending on the pathophysiological context. We compared the effect of CC-chemokine inhibition in inflammatory and physiological conditions. In vitro, the broad-spectrum CC-chemokine inhibitor "35K" inhibited inflammatory-induced endothelial cell proliferation, migration, and tubulogenesis, with more modest effects in hypoxia. In vivo, adenoviruses were used to overexpress 35K (Ad35K) and GFP (AdGFP, control virus). Plasma chemokine activity was suppressed by Ad35K in both models. In the periarterial femoral cuff model of inflammatory-driven angiogenesis, overexpression of 35K inhibited adventitial neovessel formation compared with control AdGFP-infused mice. In contrast, 35K preserved neovascularization in the hindlimb ischemia model and had no effect on physiological neovascularization in the chick chorioallantoic membrane assay. Mechanistically, 2 key angiogenic proteins (VEGF and hypoxia-inducible factor-1α) were conditionally regulated by 35K, such that expression was inhibited in inflammation but was unchanged in hypoxia. In conclusion, CC-chemokine inhibition by 35K suppresses inflammatory-driven angiogenesis while preserving physiological ischemia-mediated angiogenesis via conditional regulation of VEGF and hypoxia-inducible factor-1α. CC-chemokine inhibition may be an alternative therapeutic strategy for suppressing diseases associated with inflammatory angiogenesis without inducing the side effects caused by global inhibition.- Ridiandries, A., Tan, J. T. M., Ravindran, D., Williams, H., Medbury, H. J., Lindsay, L., Hawkins, C., Prosser, H. C. G., Bursill, C. A. CC-chemokine class inhibition attenuates pathological angiogenesis while preserving physiological angiogenesis.

  3. Cysteine Cathepsins Activate ELR Chemokines and Inactivate Non-ELR Chemokines.

    PubMed

    Repnik, Urska; Starr, Amanda E; Overall, Christopher M; Turk, Boris

    2015-05-29

    Cysteine cathepsins are primarily lysosomal proteases involved in general protein turnover, but they also have specific proteolytic functions in antigen presentation and bone remodeling. Cathepsins are most stable at acidic pH, although growing evidence indicates that they have physiologically relevant activity also at neutral pH. Post-translational proteolytic processing of mature chemokines is a key, yet underappreciated, level of chemokine regulation. Although the role of selected serine proteases and matrix metalloproteases in chemokine processing has long been known, little has been reported about the role of cysteine cathepsins. Here we evaluated cleavage of CXC ELR (CXCL1, -2, -3, -5, and -8) and non-ELR (CXCL9-12) chemokines by cysteine cathepsins B, K, L, and S at neutral pH by high resolution Tris-Tricine SDS-PAGE and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Whereas cathepsin B cleaved chemokines especially in the C-terminal region, cathepsins K, L, and S cleaved chemokines at the N terminus with glycosaminoglycans modulating cathepsin processing of chemokines. The functional consequences of the cleavages were determined by Ca(2+) mobilization and chemotaxis assays. We show that cysteine cathepsins inactivate and in some cases degrade non-ELR CXC chemokines CXCL9-12. In contrast, cathepsins specifically process ELR CXC chemokines CXCL1, -2, -3, -5, and -8 N-terminally to the ELR motif, thereby generating agonist forms. This study suggests that cysteine cathepsins regulate chemokine activity and thereby leukocyte recruitment during protective or pathological inflammation.

  4. The effects and comparative differences of neutrophil specific chemokines on neutrophil chemotaxis of the neonate.

    PubMed

    Fox, Samuel E; Lu, Wenge; Maheshwari, Akhil; Christensen, Robert D; Calhoun, Darlene A

    2005-02-07

    Neutrophil specific chemokines are potent chemoattractants for neutrophils. IL-8/CXCL8 is the most extensively studied member of this group, and its concentrations increase during inflammatory conditions of the newborn infant including sepsis and chronic lung disease. A significant amount of information exists on the effects of IL-8/CXCL8 on neutrophil chemotaxis of neonates, but little is known about the other neutrophil specific chemokines. The aim of this study was to determine the relative potency of the neutrophil specific chemokines on chemotaxis of neonatal neutrophils and to compare this effect with the effect on adult neutrophils. Neutrophils were isolated from cord blood or healthy adult donors and incubated in a Neuroprobe chemotaxis chamber. Chemokine concentrations ranging from 1-1000 ng/mL were used. Differences in chemotactic potency existed among the seven neutrophil specific chemokines. Specifically, at 100 ng/mL, the order was IL-8/CXCL8>GRO-alpha/CXCL1>GCP-2/CXCL6>NAP-2/CXCL7>ENA-78/CXCL5>GRO-gamma/CXCL2>GRO-beta/CXCL3. This pattern was observed for adult and neonatal neutrophils. We conclude that (1) neutrophils from cord blood exhibit the same pattern of potency for each ELR chemokine as neutrophils from adults, and (2) migration of neonatal neutrophils is significantly less than that of adults at every concentration examined except the lowest (1 ng/mL).

  5. Phylogenetic analysis of vertebrate CXC chemokines reveals novel lineage specific groups in teleost fish.

    PubMed

    Chen, Jun; Xu, Qiaoqing; Wang, Tiehui; Collet, Bertrand; Corripio-Miyar, Yolanda; Bird, Steve; Xie, Ping; Nie, Pin; Secombes, Christopher J; Zou, Jun

    2013-10-01

    In this study, we have identified 421 molecules across the vertebrate spectrum and propose a unified nomenclature for CXC chemokines in fish, amphibians and reptiles based on phylogenetic analysis. Expanding on earlier studies in teleost fish, lineage specific CXC chemokines that have no apparent homologues in mammals were confirmed. Furthermore, in addition to the two subgroups of the CXCL8 homologues known in teleost fish, a third group was identified (termed CXCL8_L3), as was a further subgroup of the fish CXC genes related to CXCL11. Expression of the CXC chemokines found in rainbow trout, Oncorhynchus mykiss, was studied in response to stimulation with inflammatory and antiviral cytokines, and bacterial. Tissue distribution analysis revealed distinct expression profiles for these trout CXC chemokines. Lastly three of the trout chemokines, including two novel fish specific CXC chemokines containing three pairs of cysteines, were produced as recombinant proteins and their effect on trout leucocyte migration studied. These molecules increased the relative expression of CD4 and MCSFR in migrated cells in an in vitro chemotaxis assay.

  6. Quercetin Blocks Airway Epithelial Cell Chemokine Expression

    PubMed Central

    Nanua, Suparna; Zick, Suzanna M.; Andrade, Juan E.; Sajjan, Umadevi S.; Burgess, John R.; Lukacs, Nicholas W.; Hershenson, Marc B.

    2006-01-01

    Quercetin (3,3′,4′,5,7-pentahydroxyflavone), a dietary flavonoid, is an inhibitor of phosphatidylinositol (PI) 3-kinase and potent antioxidant. We hypothesized that quercetin blocks airway epithelial cell chemokine expression via PI 3-kinase–dependent mechanisms. Pretreatment with quercetin and the PI 3–kinase inhibitor LY294002 each reduced TNF-α–induced IL-8 and monocyte chemoattractant protein (MCP)-1 (also called CCL2) expression in cultured human airway epithelial cells. Quercetin also inhibited TNF-α–induced PI 3-kinase activity, Akt phosphorylation, intracellular H2O2 production, NF-κB transactivation, IL-8 promoter activity, and steady-state mRNA levels, consistent with the notion that quercetin inhibits chemokine expression by attenuating NF-κB transactivation via a PI 3-kinase/Akt-dependent pathway. Quercetin also reduced TNF-α–induced chemokine secretion in the presence of the transcriptional inhibitor actinomycin D, while inducing phosphorylation of eukaryotic translation initiation factor (eIF)-2α, suggesting that quercetin attenuates chemokine expression by post-transcriptional as well as transcriptional mechanisms. Finally, we tested the effects of quercetin in cockroach antigen–sensitized and –challenged mice. These mice show MCP-1–dependent airways hyperresponsiveness and inflammation. Quercetin significantly reduced lung MCP-1 and methacholine responsiveness. We conclude that quercetin blocks airway cell chemokine expression via transcriptional and post-transcriptional pathways. PMID:16794257

  7. Increased signals from short-wavelength-excited fluorescent molecules using sub-Ti:Sapphire wavelengths.

    PubMed

    Norris, G; Amor, R; Dempster, J; Amos, W B; McConnell, G

    2012-11-01

    We report the use of an all-solid-state ultrashort pulsed source specifically for two-photon microscopy at wavelengths shorter than those of the conventional Ti:Sapphire laser. Our approach involves sum-frequency mixing of the output from an optical parametric oscillator (λ= 1400-1640 nm) synchronously pumped by a Yb-doped fibre laser (λ= 1064 nm), with the residual pump radiation. This generated an fs-pulsed output tunable in the red spectral region (λ= 620-636 nm, ~150 mW, 405 fs, 80 MHz, M(2) ~ 1.3). We demonstrate the performance of our ultrashort pulsed system using fluorescently labelled and autofluorescent tissue, and compare with conventional Ti:Sapphire excitation. We observe a more than 3-fold increase in fluorescence signal intensity using our visible laser source in comparison with the Ti:Sapphire laser for two-photon excitation at equal illumination peak powers of 1.16 kW or less.

  8. Putrescine as a signal to modulate the indispensable ABA increase under cold stress

    PubMed Central

    Cuevas, Juan C; López-Cobollo, Rosa; Alcázar, Rubén; Zarza, Xavier; Koncz, Csaba; Altabella, Teresa; Salinas, Julio; Tiburcio, Antonio F

    2009-01-01

    Polyamines have been found to correlate frequently with biotic and abiotic insults, and their functional involvement in the plant responses to several stresses has been shown genetically with both gain and loss of function mutations. In spite of a large body of physiological and genetic data, the mode of action for polyamines at the molecular level still remains elusive. We have recently performed a detailed integrated analysis of polyamine metabolism under cold stress by means of metabolic studies, quantitative gene expression analyses, and gene inactivations, to characterize in more detail the role of polyamines in response to low temperature. Our data show a unique accumulation profile for putrescine compared to other polyamines, with a progressive increase upon cold stress treatment coincident with a similar transcriptional upregulation for the two arginine decarboxylase genes ADC1 and ADC2. Loss of function mutants adc1 and adc2 display reduced freezing tolerance and alterations in ABA content and ABA-dependent signalling pathways under low temperature, compared to wild type plants. Phenotypical reverse complementation tests for both adc and ABA-defective mutants support our conclusion that putrescine modulates ABA biosynthesis at the transcriptional level in response to low temperature thus uncovering a novel mode of action for polyamines as regulators of hormone biosynthesis. PMID:19721755

  9. Altered prostanoid signaling contributes to increased skin tumorigenesis in Tpl2 knockout mice.

    PubMed

    DeCicco-Skinner, Kathleen L; Nolan, Sabrina J; Deshpande, Monika M; Trovato, Erika L; Dempsey, Taylor A; Wiest, Jonathan S

    2013-01-01

    Squamous cell carcinoma is the second most common form of skin cancer with the incidence expected to double over the next 20 years. Inflammation is believed to be a critical component in skin cancer progression. Therefore, understanding genes involved in the regulation of inflammatory pathways is vital to the design of targeted therapies. Numerous studies show cyclooxygenases (COXs) play an essential role in inflammation-associated cancers. Tpl2 (MAP3K8) is a protein kinase in the MAP Kinase signal transduction cascade. Previous research using a two-stage skin carcinogenesis model revealed that Tpl2(-/-) mice have significantly higher tumor incidence and inflammatory response than wild-type (WT) controls. The current study investigates whether cyclooxygenase-2 (COX-2) and COX-2- regulated prostaglandins and prostaglandin receptors drive the highly tumorigenic state of Tpl2(-/-) mice by investigating the relationship between Tpl2 and COX-2. Keratinocytes from newborn WT or Tpl2(-/-) mice were treated with 12-O-tetradecanoylphorbol-13-acetate (TPA) for various times over 24 hours. Western analysis revealed significant differences in COX-2 and COX-2 dependent prostanoids and prostanoid receptors. Additionally, in vivo experiments confirmed that COX-2 and COX-2 downstream factors were elevated in TPA-treated Tpl2(-/-) skin, as well as in papillomas from Tpl2(-/-) mice. Use of the selective COX-2 inhibitor Celecoxib showed the increased tumorigenesis in the Tpl2(-/-) mice to primarily be mediated through COX-2. These experiments illustrate COX-2 induction in the absence of Tpl2 may be responsible for the increased tumorigenesis found in Tpl2(-/-) mice. Defining the relationship between Tpl2 and COX-2 may lead to new ways to downregulate COX-2 through the modulation of Tpl2.

  10. Caffeine increases mitochondrial function and blocks melatonin signaling to mitochondria in Alzheimer's mice and cells.

    PubMed

    Dragicevic, Natasa; Delic, Vedad; Cao, Chuanhai; Copes, Neil; Lin, Xiaoyang; Mamcarz, Maggie; Wang, Li; Arendash, Gary W; Bradshaw, Patrick C

    2012-12-01

    Caffeine and melatonin have been shown to protect the Swedish mutant amyloid precursor protein (APP(sw)) transgenic mouse model of Alzheimer's disease from cognitive dysfunction. But their mechanisms of action remain incompletely understood. These Alzheimer's mice have extensive mitochondrial dysfunction, which likely contributes to their cognitive decline. To further explore the mechanism through which caffeine and melatonin protect cognitive function in these mice, we monitored the function of isolated mitochondria from APP(sw) mice treated with caffeine, melatonin, or both in their drinking water for one month. Melatonin treatment yielded a near complete restoration of mitochondrial function in assays of respiratory rate, membrane potential, reactive oxygen species production, and ATP levels. Caffeine treatment by itself yielded a small increase in mitochondrial function. However, caffeine largely blocked the large enhancement of mitochondrial function provided by melatonin. Studies with N2a neuroblastoma cells stably expressing APP(sw) showed that specific inhibition of cAMP-dependent phosphodiesterase (PDE) 4 or cGMP-dependent PDE5 also blocked melatonin protection of mitochondrial function, but A(2a) and A₁ adenosine receptor antagonists were without effect. Melatonin or caffeine at the concentrations used to modulate mitochondrial function in the cells had no effect on cAMP-dependent PDE activity or cellular cAMP or cGMP levels. Therefore, caffeine and increased cyclic nucleotide levels likely block melatonin signaling to mitochondria by independent mechanisms that do not involve adenosine receptor antagonism. The results of this study indicate that melatonin restores mitochondrial function much more potently than caffeine in APP(sw) transgenic mouse and cell models of Alzheimer's disease.

  11. Strong Static Magnetic Fields Increase the Gel Signal in Partially Hydrated DPPC/DMPC Membranes.

    PubMed

    Tang, Jennifer; Alsop, Richard J; Schmalzl, Karin; Epand, Richard M; Rheinstädter, Maikel C

    2015-09-29

    NIt was recently reported that static magnetic fields increase lipid order in the hydrophobic membrane core of dehydrated native plant plasma membranes [Poinapen, Soft Matter 9:6804-6813, 2013]. As plasma membranes are multicomponent, highly complex structures, in order to elucidate the origin of this effect, we prepared model membranes consisting of a lipid species with low and high melting temperature. By controlling the temperature, bilayers coexisting of small gel and fluid domains were prepared as a basic model for the plasma membrane core. We studied molecular order in mixed lipid membranes made of dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) using neutron diffraction in the presence of strong static magnetic fields up to 3.5 T. The contribution of the hydrophobic membrane core was highlighted through deuterium labeling the lipid acyl chains. There was no observable effect on lipid organization in fluid or gel domains at high hydration of the membranes. However, lipid order was found to be enhanced at a reduced relative humidity of 43%: a magnetic field of 3.5 T led to an increase of the gel signal in the diffraction patterns of 5%. While all biological materials have weak diamagnetic properties, the corresponding energy is too small to compete against thermal disorder or viscous effects in the case of lipid molecules. We tentatively propose that the interaction between the fatty acid chains' electric moment and the external magnetic field is driving the lipid tails in the hydrophobic membrane core into a better ordered state.

  12. Clarithromycin increases neuronal excitability in CA3 pyramidal neurons through a reduction in GABAergic signaling.

    PubMed

    Bichler, Edyta K; Elder, Courtney C; García, Paul S

    2017-01-01

    Antibiotics are used in the treatment and prevention of bacterial infections, but effects on neuron excitability have been documented. A recent study demonstrated that clarithromycin alleviates daytime sleepiness in hypersomnia patients (Trotti LM, Saini P, Freeman AA, Bliwise DL, García PS, Jenkins A, Rye DB. J Psychopharmacol 28: 697-702, 2014). To explore the potential application of clarithromycin as a stimulant, we performed whole cell patch-clamp recordings in rat pyramidal cells from the CA3 region of hippocampus. In the presence of the antibiotic, rheobase current was reduced by 50%, F-I relationship (number of action potentials as a function of injected current) was shifted to the left, and the resting membrane potential was more depolarized. Clarithromycin-induced hyperexcitability was dose dependent; doses of 30 and 300 μM clarithromycin significantly increased the firing frequency and membrane potential compared with controls (P = 0.003, P < 0.0001). We hypothesized that clarithromycin enhanced excitability by reducing GABAA receptor activation. Clarithromycin at 30 μM significantly reduced (P = 0.001) the amplitude of spontaneous miniature inhibitory GABAergic currents and at 300 μM had a minor effect on action potential width. Additionally, we tested the effect of clarithromycin in an ex vivo seizure model by evaluating its effect on spontaneous local field potentials. Bath application of 300 μM clarithromycin enhanced burst frequency twofold compared with controls (P = 0.0006). Taken together, these results suggest that blocking GABAergic signaling with clarithromycin increases cellular excitability and potentially serves as a stimulant, facilitating emergence from anesthesia or normalizing vigilance in hypersomnia and narcolepsy. However, the administration of clarithromycin should be carefully considered in patients with seizure disorders.

  13. Laminar chemokine mRNA concentrations in horses with carbohydrate overload-induced laminitis.

    PubMed

    Faleiros, Rafael R; Leise, Britta S; Watts, Mauria; Johnson, Philip J; Black, Samuel J; Belknap, James K

    2011-11-15

    Chemokines play a vital role in leukocyte activation and emigration that reportedly plays a central role in laminar injury in equine laminitis. The purpose of this study was to evaluate the pattern of laminar chemokine expression in horses in the classical carbohydrate overload (CHO)-model of laminitis. Laminar samples were obtained 24h following water administration in the control group (CON, n=8), and at the onset of fever (≥ 102°F, 12-22 h post CHO, DEV group, n=8) and at the onset of lameness (20-48 h post CHO, LAM group, n=8) in induced horses. Real time quantitative PCR was performed on all samples in order to determine laminar mRNA concentrations of both CXC chemokines (CXCL1, CXCL6, CXCL8) and CC chemokines (CCL2 [MCP-1], CCL3 [MIP-1α], and CCL8 [MCP-2]). Data were subjected to ANOVA followed by Student-Newman-Keuls (P<0.05). Laminar mRNA concentrations for all CXC chemokines were increased (P<0.05) at both the DEV and LAM horses when compared to the control horses, whereas mRNA concentrations of CCL2 and CCL8 were only increased in the LAM horses when compared to controls and the DEV horses. When taken in context with our previous studies, CXCL1, CXCL6 and CXCL8 increases precede peak laminar leukocyte accumulation. Additionally, CCL2 and CCL8 expression corroborate previous reports of monocyte/macrophage accumulation in affected laminae. Compared with previous studies, our findings demonstrate that increased laminar CXC chemokine expression consistently precedes peak leukocyte accumulation and onset of lameness in CHO laminitis models. Chemokine antagonists may be considered as possible therapeutic targets to decrease the influx of leukocytes that occurs during the development of equine laminitis.

  14. Potential Role of Chemokines in Fracture Repair

    PubMed Central

    Edderkaoui, Bouchra

    2017-01-01

    Chemokines are a family of small cytokines that share a typical key structure that is stabilized by disulfide bonds between the cysteine residues at the NH2-terminal of the protein, and they are secreted by a great variety of cells in several different conditions. Their function is directly dependent on their interactions with their receptors. Chemokines are involved in cell maturation and differentiation, infection, autoimmunity, cancer, and, in general, in any situation where immune components are involved. However, their role in postfracture inflammation and fracture healing is not yet well established. In this article, we will discuss the response of chemokines to bone fracture and their potential roles in postfracture inflammation and healing based on data from our studies and from other previously published studies. PMID:28303118

  15. Molecular piracy of chemokine receptors by herpesviruses.

    PubMed

    Murphy, P M

    1994-01-01

    To succeed as a biological entity, viruses must exploit normal cellular functions and elude the host immune system; they often do so by molecular mimicry. One way that mimicry may occur is when viruses copy and modify host genes. The best studied examples of this are the oncogenes of RNA retroviruses, but a growing number of examples are also known for DNA viruses. So far they all come from just two groups of DNA viruses, the herpesviruses and poxviruses, and the majority of examples are for genes whose products regulate immune responses, such as cytokines, cytokine receptors, and complement control proteins. This review will focus on human and herpesvirus receptors for chemokines, a family of leukocyte chemoattractant and activating factors that are thought to be important mediators of inflammation. Although the biological roles of the viral chemokine receptor homologues are currently unknown, their connection to specific sets of chemokines has suggested a number of possible functions.

  16. Role of cytokines and chemokines in alcohol-induced tumor promotion

    PubMed Central

    Chen, Danlei; Zhang, Fengyun; Ren, Haifeng; Luo, Jia; Wang, Siying

    2017-01-01

    Excessive chronic alcohol consumption has become a worldwide health problem. The oncogenic effect of chronic alcohol consumption is one of the leading concerns. The mechanisms of alcohol-induced tumorigenesis and tumor progression are largely unknown, although many factors have been implicated in the process. This review discusses the recent progress in this research area with concentration on alcohol-induced dysregulation of cytokines and chemokines. Based on the available evidence, we propose that alcohol promotes tumor progression by the dysregulation of the cytokine/chemokine system. In addition, we discuss specific transcription factors and signaling pathways that are involved in the action of these cytokines/chemokines and the oncogenic effect of alcohol. This review provides novel insight into the mechanisms of alcohol-induced tumor promotion. PMID:28360527

  17. Structure of the CCR5 Chemokine Receptor-HIV Entry Inhibitor Maraviroc Complex

    SciTech Connect

    Tan, Qiuxiang; Zhu, Ya; Li, Jian; Chen, Zhuxi; Han, Gye Won; Kufareva, Irina; Li, Tingting; Ma, Limin; Fenalti, Gustavo; Li, Jing; Zhang, Wenru; Xie, Xin; Yang, Huaiyu; Jiang, Hualiang; Cherezov, Vadim; Liu, Hong; Stevens, Raymond C.; Zhao, Qiang; Wu, Beili

    2013-10-21

    The CCR5 chemokine receptor acts as a co-receptor for HIV-1 viral entry. Here we report the 2.7 angstrom–resolution crystal structure of human CCR5 bound to the marketed HIV drug maraviroc. The structure reveals a ligand-binding site that is distinct from the proposed major recognition sites for chemokines and the viral glycoprotein gp120, providing insights into the mechanism of allosteric inhibition of chemokine signaling and viral entry. A comparison between CCR5 and CXCR4 crystal structures, along with models of co-receptor–gp120-V3 complexes, suggests that different charge distributions and steric hindrances caused by residue substitutions may be major determinants of HIV-1 co-receptor selectivity. These high-resolution insights into CCR5 can enable structure-based drug discovery for the treatment of HIV-1 infection.

  18. Chemokine Receptor-Specific Antibodies in Cancer Immunotherapy: Achievements and Challenges

    PubMed Central

    Vela, Maria; Aris, Mariana; Llorente, Mercedes; Garcia-Sanz, Jose A.; Kremer, Leonor

    2015-01-01

    The 1990s brought a burst of information regarding the structure, expression pattern, and role in leukocyte migration and adhesion of chemokines and their receptors. At that time, the FDA approved the first therapeutic antibodies for cancer treatment. A few years later, it was reported that the chemokine receptors CXCR4 and CCR7 were involved on directing metastases to liver, lung, bone marrow, or lymph nodes, and the over-expression of CCR4, CCR6, and CCR9 by certain tumors. The possibility of inhibiting the interaction of chemokine receptors present on the surface of tumor cells with their ligands emerged as a new therapeutic approach. Therefore, many research groups and companies began to develop small molecule antagonists and specific antibodies, aiming to neutralize signaling from these receptors. Despite great expectations, so far, only one anti-chemokine receptor antibody has been approved for its clinical use, mogamulizumab, an anti-CCR4 antibody, granted in Japan to treat refractory adult T-cell leukemia and lymphoma. Here, we review the main achievements obtained with anti-chemokine receptor antibodies for cancer immunotherapy, including discovery and clinical studies, proposed mechanisms of action, and therapeutic applications. PMID:25688243

  19. Arsenic Attenuates GLI Signaling, Increasing or Decreasing its Transcriptional Program in a Context-Dependent Manner.

    PubMed

    Li, Bin; Giambelli, Camilla; Tang, Bo; Winterbottom, Emily; Long, Jun; Jin, Ke; Wang, Zhiqiang; Fei, Dennis Liang; Nguyen, Dao M; Athar, Mohammad; Wang, Baolin; Subbarayan, Pochi R; Wang, Lily; Rai, Priyamvada; Ardalan, Bach; Capobianco, Anthony J; Robbins, David J

    2016-02-01

    The metalloid arsenic is a worldwide environmental toxicant, exposure to which is associated with many adverse outcomes. Arsenic is also an effective therapeutic agent in certain disease settings. Arsenic was recently shown to regulate the activity of the Hedgehog (HH) signal transduction pathway, and this regulation of HH signaling was proposed to be responsible for a subset of arsenic's biologic effects. Surprisingly, these separate reports proposed contradictory activities for arsenic, as either an agonist or antagonist of HH signaling. Here we provide in vitro and in vivo evidence that arsenic acts as a modulator of the activity of the HH effector protein glioma-associated oncogene family zinc finger (GLI), activating or inhibiting GLI activity in a context-dependent manner. This arsenic-induced modulation of HH signaling is observed in cultured cells, patients with colorectal cancer who have received arsenic-based therapy, and a mouse colorectal cancer xenograft model. Our results show that arsenic activates GLI signaling when the intrinsic GLI activity is low but inhibits signaling in the presence of high-level GLI activity. Furthermore, we show that this modulation occurs downstream of primary cilia, evidenced by experiments in suppressor of fused homolog (SUFU) deficient cells. Combining our findings with previous reports, we present an inclusive model in which arsenic plays dual roles in GLI signaling modulation: when GLIs are primarily in their repressor form, arsenic antagonizes their repression capacity, leading to low-level GLI activation, but when GLIs are primarily in their activator form, arsenic attenuates their activity.

  20. Integration of signals along orthogonal axes of the vertebrate neural tube controls progenitor competence and increases cell diversity.

    PubMed

    Sasai, Noriaki; Kutejova, Eva; Briscoe, James

    2014-07-01

    A relatively small number of signals are responsible for the variety and pattern of cell types generated in developing embryos. In part this is achieved by exploiting differences in the concentration or duration of signaling to increase cellular diversity. In addition, however, changes in cellular competence-temporal shifts in the response of cells to a signal-contribute to the array of cell types generated. Here we investigate how these two mechanisms are combined in the vertebrate neural tube to increase the range of cell types and deliver spatial control over their location. We provide evidence that FGF signaling emanating from the posterior of the embryo controls a change in competence of neural progenitors to Shh and BMP, the two morphogens that are responsible for patterning the ventral and dorsal regions of the neural tube, respectively. Newly generated neural progenitors are exposed to FGF signaling, and this maintains the expression of the Nk1-class transcription factor Nkx1.2. Ventrally, this acts in combination with the Shh-induced transcription factor FoxA2 to specify floor plate cells and dorsally in combination with BMP signaling to induce neural crest cells. As development progresses, the intersection of FGF with BMP and Shh signals is interrupted by axis elongation, resulting in the loss of Nkx1.2 expression and allowing the induction of ventral and dorsal interneuron progenitors by Shh and BMP signaling to supervene. Hence a similar mechanism increases cell type diversity at both dorsal and ventral poles of the neural tube. Together these data reveal that tissue morphogenesis produces changes in the coincidence of signals acting along orthogonal axes of the neural tube and this is used to define spatial and temporal transitions in the competence of cells to interpret morphogen signaling.

  1. Chemokines and cytokines network in the pathogenesis of the inflammatory skin diseases: atopic dermatitis, psoriasis and skin mastocytosis.

    PubMed

    Nedoszytko, Bogusław; Sokołowska-Wojdyło, Małgorzata; Ruckemann-Dziurdzińska, Katarzyna; Roszkiewicz, Jadwiga; Nowicki, Roman J

    2014-05-01

    Chemokines are signaling peptides which regulate cell trafficking and provide control of the tissue-specific cell homing. In the skin, chemokines are secreted both by the resident cells such as keratinocytes, melanocytes, fibroblasts, dendritic cells and mast cells, as well as by infiltrated cells - lymphocytes, eosinophils, and monocytes. Chemokines, together with cytokines, participate in induction and maintenance of inflammation in the skin and regulate the composition of the cellular infiltrates. Inflammation within the skin is a feature shared by atopic dermatitis and psoriasis, two of the most common dermatoses. Accumulation of activated mast cells in the affected skin is seen both in atopic dermatitis and in psoriasis. This paper presents a concise overview of the current knowledge on the role chemokines have in pathogenesis of atopic dermatitis, psoriasis, and mastocytosis, a disease caused directly by the accumulation and activation of mast cells in the skin.

  2. Decidual Cell Regulation of Natural Killer Cell–Recruiting Chemokines

    PubMed Central

    Lockwood, Charles J.; Huang, S. Joseph; Chen, Chie-Pein; Huang, Yingqun; Xu, Jie; Faramarzi, Saeed; Kayisli, Ozlem; Kayisli, Umit; Koopman, Louise; Smedts, Dineke; Buchwalder, Lynn F.; Schatz, Frederick

    2014-01-01

    First trimester human decidua is composed of decidual cells, CD56brightCD16− decidual natural killer (dNK) cells, and macrophages. Decidual cells incubated with NK cell–derived IFN-γ and either macrophage-derived TNF-α or IL-1β synergistically enhanced mRNA and protein expression of IP-10 and I-TAC. Both chemokines recruit CXCR3-expressing NK cells. This synergy required IFN-γ receptor 1 and 2 mediation via JAK/STAT and NFκB signaling pathways. However, synergy was not observed on neutrophil, monocyte, and NK cell–recruiting chemokines. Immunostaining of first trimester decidua localized IP-10, I-TAC, IFN-γR1, and -R2 to vimentin-positive decidual cells versus cytokeratin-positive interstitial trophoblasts. Flow cytometry identified high CXCR3 levels on dNK cells and minority peripheral CD56brightCD16− pNK cells and intermediate CXCR3 levels on the majority of CD56dimCD16+ pNK cells. Incubation of pNK cells with either IP-10 or I-TAC elicited concentration-dependent enhanced CXCR3 levels and migration of both pNK cell subsets that peaked at 10 ng/mL, whereas each chemokine at a concentration of 50 ng/mL inhibited CXCR3 expression and pNK cell migration. Deciduae from women with preeclampsia, a leading cause of maternal and fetal morbidity and mortality, displayed significantly lower dNK cell numbers and higher IP-10 and I-TAC levels versus gestational age–matched controls. Significantly elevated IP-10 levels in first trimester sera from women eventually developing preeclampsia compared with controls, identifying IP-10 as a novel, robust early predictor of preeclampsia. PMID:23973270

  3. Expression of Chemokine XCL2 and CX3CL1 in Lung Cancer

    PubMed Central

    Zhou, Bing; Xu, Heyun; Ni, Kewei; Ni, Xuming; Shen, Jian

    2016-01-01

    Background Chemokines are a family of small proteins secreted by cells with chemotactic activity, and they play important roles in cell adhesion. However, the expression of chemokine XCL2 and CX3CL1 in lung cancers in different pathological stages remains unclear. Material/Methods XCL2 and CX3CL1 expression in lung cancers and adjacent non-cancerous tissues was detected by quantitative PCR and ELISA. The relative expression of both chemokines in lung cancers in different pathological stages was compared by immunohistochemical assay. Results The relative expression level of XCL2 and CX3CL1 in lung cancer was significantly higher compared with adjacent normal tissues (P<0.001). The expression level of both chemokines was significantly increased with higher pathological stages, as indicated by immunohistochemical assay (P<0.05 or P <0.001). Their expression level in cancers with higher numbers of metastatic lymph nodes was also significantly increased compared with cancers with lower numbers of metastatic lymph nodes (P<0.05 or P<0.001). Conclusions The expression of XCL2 and CX3CL1 increases with increasing degree of malignancy, indicating that both chemokines might be important targets in gene therapy for lung cancer. PMID:27156946

  4. Individuals with increased inflammatory response to ozone demonstrate muted signaling of immune cell trafficking pathways

    EPA Science Inventory

    Background Exposure to ozone activates innate immune function and causes neutrophilic (PMN) airway inflammation that in some individuals is robustly elevated. The interplay between immunoinflammatory function and genomic signaling in those with heightened inflammatory responsive...

  5. Chemokines as effector and target molecules in vascular biology.

    PubMed

    Sozzani, Silvano; Del Prete, Annalisa; Bonecchi, Raffaella; Locati, Massimo

    2015-08-01

    Chemokines are key mediators of inflammation. In pathological tissues, the main roles of chemokines are to regulate leucocyte accumulation through the activation of oriented cell migration and the activation of limited programs of gene transcription. Through these activities, chemokines exert many crucial functions, including the regulation of angiogenesis. The 'chemokine system' is tightly regulated at several levels, such as the post-transcriptional processing of ligands, the regulation of the expression and function of the receptors and through the expression of molecules known as 'atypical chemokine receptors', proteins that function as chemokine scavenging and presenting molecules. Several experimental evidence obtained in vitro, in animal models and in human studies, has defined a crucial role of chemokines in cardiovascular diseases. An intense area of research is currently exploring the possibility to develop new effective therapeutic strategies through the identification of chemokine receptor antagonists.

  6. Differential CCR7 Targeting in Dendritic Cells by Three Naturally Occurring CC-Chemokines

    PubMed Central

    Hjortø, Gertrud M.; Larsen, Olav; Steen, Anne; Daugvilaite, Viktorija; Berg, Christian; Fares, Suzan; Hansen, Morten; Ali, Simi; Rosenkilde, Mette M.

    2016-01-01

    The CCR7 ligands CCL19 and CCL21 are increasingly recognized as functionally different (biased). Using mature human dendritic cells (DCs), we show that CCL19 is more potent than CCL21 in inducing 3D chemotaxis. Intriguingly, CCL21 induces prolonged and more efficient ERK1/2 activation compared with CCL19 and a C-terminal truncated (tailless) CCL21 in DCs. In contrast, tailless-CCL21 displays increased potency in DC chemotaxis compared with native CCL21. Using a CCL21-specific antibody, we show that CCL21, but not tailless-CCL21, accumulates at the cell surface. In addition, removal of sialic acid from the cell surface by neuraminidase treatment impairs ERK1/2 activation by CCL21, but not by CCL19 or tailless-CCL21. Using standard laboratory cell lines, we observe low potency of both CCL21 and tailless-CCL21 in G protein activation and β-arrestin recruitment compared with CCL19, indicating that the tail itself does not improve receptor interaction. Chemokines interact with their receptors in a stepwise manner with ultimate docking of their N-terminus into the main binding pocket. Employing site-directed mutagenesis we identify residues in this pocket of selective CCL21 importance. We also identify a molecular switch in the top of TM7 important for keeping CCR7 in an inactive conformation (Tyr312), as introduction of the chemokine receptor-conserved Glu (or Ala) induces high constitutive activity. Summarized, we show that the interaction of the tail of CCL21 with polysialic acid is needed for strong ERK signaling, whereas it impairs CCL21-mediated chemotaxis and has no impact on receptor docking consistent with the current model of chemokine:receptor interaction. This indicates that future selective pharmacological targeting of CCL19 versus CCL21 should focus on a differential targeting of the main receptor pocket, while selective targeting of tailless-CCL21 versus CCL21 and CCL19 requires targeting of the glycosaminoglycan (GAG) interaction. PMID:28018341

  7. Androgen receptor (AR) signaling promotes RCC progression via increased endothelial cell proliferation and recruitment by modulating AKT → NF-κB → CXCL5 signaling

    PubMed Central

    Guan, Zhenfeng; Li, Chong; Fan, Jinhai; He, Dalin; Li, Lei

    2016-01-01

    Androgen receptor (AR) signaling may promote renal cell carcinoma (RCC) progression via altered HIF-2α/VEGF signaling. However, it remains unclear whether AR signaling also promotes RCC progression by recruiting vascular endothelial cells (ECs), key players in the development of blood vessels. In our study, AR increased EC proliferation and recruitment to the tumor microenvironment and promoted RCC progression. Mechanistically, AR modulated cytokine CXCL5 expression by altering AKT → NF-κB signaling, and interruption of AKT → NF-κB → CXCL5 signaling using either specific inhibitors or siRNA suppressed AR-enhanced EC recruitment and AR-EC-promoted RCC progression. The results obtained using an in vivo mouse model and a human clinical sample survey confirmed the role of AR in promoting RCC progression through enhancement of EC proliferation and/or recruitment via altered AKT → NF-κB → CXCL5 signaling. Targeting this newly identified AR-induced AKT → NF-κB → CXCL5 pathway may facilitate the development of new therapies for slowing RCC progression. PMID:27848972

  8. Androgen receptor (AR) signaling promotes RCC progression via increased endothelial cell proliferation and recruitment by modulating AKT → NF-κB → CXCL5 signaling.

    PubMed

    Guan, Zhenfeng; Li, Chong; Fan, Jinhai; He, Dalin; Li, Lei

    2016-11-16

    Androgen receptor (AR) signaling may promote renal cell carcinoma (RCC) progression via altered HIF-2α/VEGF signaling. However, it remains unclear whether AR signaling also promotes RCC progression by recruiting vascular endothelial cells (ECs), key players in the development of blood vessels. In our study, AR increased EC proliferation and recruitment to the tumor microenvironment and promoted RCC progression. Mechanistically, AR modulated cytokine CXCL5 expression by altering AKT → NF-κB signaling, and interruption of AKT → NF-κB → CXCL5 signaling using either specific inhibitors or siRNA suppressed AR-enhanced EC recruitment and AR-EC-promoted RCC progression. The results obtained using an in vivo mouse model and a human clinical sample survey confirmed the role of AR in promoting RCC progression through enhancement of EC proliferation and/or recruitment via altered AKT → NF-κB → CXCL5 signaling. Targeting this newly identified AR-induced AKT → NF-κB → CXCL5 pathway may facilitate the development of new therapies for slowing RCC progression.

  9. Obesity-Dependent Increases in Oocyte mRNAs Are Associated With Increases in Proinflammatory Signaling and Gut Microbial Abundance of Lachnospiraceae in Female Mice.

    PubMed

    Xie, Fang; Anderson, Christopher L; Timme, Kelsey R; Kurz, Scott G; Fernando, Samodha C; Wood, Jennifer R

    2016-04-01

    RNAs stored in the metaphase II-arrested oocyte play important roles in successful embryonic development. Their abundance is defined by transcriptional activity during oocyte growth and selective degradation of transcripts during LH-induced oocyte maturation. Our previous studies demonstrated that mRNA abundance is increased in mature ovulated oocytes collected from obese humans and mice and therefore may contribute to reduced oocyte developmental competence associated with metabolic dysfunction. In the current study mouse models of diet-induced obesity were used to determine whether obesity-dependent increases in proinflammatory signaling regulate ovarian abundance of oocyte-specific mRNAs. The abundance of oocyte-specific Bnc1, Dppa3, and Pou5f1 mRNAs as well as markers of proinflammatory signaling were significantly increased in ovaries of obese compared with lean mice which were depleted of fully grown preovulatory follicles. Chromatin-immunoprecipitation analyses also demonstrated increased association of phosphorylated signal transducer and activator of transcription 3 with the Pou5f1 promoter in ovaries of obese mice suggesting that proinflammatory signaling regulates transcription of this gene in the oocyte. The cecum microbial content of lean and obese female mice was subsequently examined to identify potential relationships between microbial composition and proinflammatory signaling in the ovary. Multivariate Association with Linear Models identified significant positive correlations between cecum abundance of the bacterial family Lachnospiraceae and ovarian abundance of Tnfa as well as Dppa3, Bnc1, and Pou5f1 mRNAs. Together, these data suggest that diet-induced changes in gut microbial composition may be contributing to ovarian inflammation which in turn alters ovarian gene expression and ultimately contributes to obesity-dependent reduction in oocyte quality and development of infertility in obese patients.

  10. Alantolactone from Saussurea lappa Exerts Antiinflammatory Effects by Inhibiting Chemokine Production and STAT1 Phosphorylation in TNF-α and IFN-γ-induced in HaCaT cells.

    PubMed

    Lim, Hye-Sun; Jin, Sung-Eun; Kim, Ohn-Soon; Shin, Hyeun-Kyoo; Jeong, Soo-Jin

    2015-07-01

    Skin inflammation is the most common condition seen in dermatology practice and can be caused by various allergic reactions and certain toxins or chemicals. In the present study, we investigated the antiinflammatory effects of Saussurea lappa, a medicinal herb, and its marker compounds alantolactone, caryophyllene, costic acid, costunolide, and dehydrocostuslactone in the HaCaT human keratinocyte cell line. HaCaT cells were stimulated with tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ), and treated with S. lappa or each of five marker compounds. Chemokine production and expression were analyzed by enzyme-linked immunosorbent assay and reverse transcription-polymerase chain reaction, respectively. Phosphorylation of signal transducer and activator of transcription (STAT) 1 was determined by immunoblotting. Stimulation with TNF-α and IFN-γ significantly increased the production of the following chemokines: thymus-regulated and activation-regulated chemokine (TARC): regulated on activation, normal T-cell expressed and secreted (RANTES): macrophage-derived chemokine (MDC): and interleukin-8 (IL-8). By contrast, S. lappa and the five marker compounds significantly reduced the production of these chemokines by TNF-α and IFN-γ-treated cells. S. lappa and alantolactone suppressed the TNF-α and IFN-γ-stimulated increase in the phosphorylation of STAT1. Our results demonstrate that alantolactone from S. lappa suppresses TNF-α and IFN-γ-induced production of RANTES and IL-8 by blocking STAT1 phosphorylation in HaCaT cells.

  11. CC chemokine receptor-like 1 functions as a tumour suppressor by impairing CCR7-related chemotaxis in hepatocellular carcinoma.

    PubMed

    Shi, Jie-Yi; Yang, Liu-Xiao; Wang, Zhi-Chao; Wang, Ling-Yan; Zhou, Jian; Wang, Xiao-Ying; Shi, Guo-Ming; Ding, Zhen-Bin; Ke, Ai-Wu; Dai, Zhi; Qiu, Shuang-Jian; Tang, Qi-Qun; Gao, Qiang; Fan, Jia

    2015-03-01

    Atypical chemokine receptors (ACRs) have been discovered to participate in the regulation of tumour behaviour. Here we report a tumour-suppressive role of a novel ACR member, CC chemokine receptor like 1 (CCRL1), in human hepatocellular carcinoma (HCC). Both mRNA and protein expressions of CCRL1 correlated with the malignant phenotype of HCC cells and were significantly down-regulated in tumour tissue compared with paired normal liver tissue. In both the initial and validation cohorts (n = 240 and n = 384, respectively), CCRL1 deficiency was associated with advanced tumour stage and was an independent index for worse survival and increased recurrence. Furthermore, knock-down or forced expression of CCRL1 revealed that CCRL1 suppressed the proliferation and invasion of HCC cells in vitro and reduced tumour growth and lung metastasis in vivo, with depressed levels of CCL19 and CCL21. By sequestrating CCL19 and CCL21, CCRL1 reduced their binding to CCR7 and consequently mitigated the detrimental impact of CCR7, including Akt-GSK3β pathway activation and nuclear accumulation of β-catenin in tumour cells. Clinically, the prognostic value of the CCR7 expression in HCC depended on the expression level of CCRL1, suggesting that CCRL1 may serve as an upstream switch for the CCR7 signalling cascade. Together, our findings suggest that CCRL1 impairs chemotactic events associated with CCR7 in the progression and metastasis of HCC. Our results also show a potential interplay between typical and atypical chemokine receptors in human cancer. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

  12. Regulation of neuronal ferritin heavy chain, a new player in opiate-induced chemokine dysfunction

    PubMed Central

    Abt, Anna Cook; Meucci, Olimpia

    2013-01-01

    The heavy chain subunit of ferritin (FHC), a ubiquitous protein best known for its iron-sequestering activity as part of the ferritin complex, has recently been described as a novel inhibitor of signaling through the chemokine receptor CXCR4. Levels of FHC as well as its effects on CXCR4 activation increase in cortical neurons exposed to mu-opioid receptor agonists such as morphine, an effect likely specific to neurons. Major actions of CXCR4 signaling in the mature brain include a promotion of neurogenesis, activation of pro-survival signals, and modulation of excitotoxic pathways; thus FHC up-regulation may contribute to the neuronal dysfunction often associated with opiate drug abuse. This review summarizes our knowledge of neuronal CXCR4 function, its regulation by opiates and the role of FHC in this process, and known mechanisms controlling FHC production. We speculate on the mechanism involved in FHC regulation by opiates, and offer FHC as a new target in opioid-induced neuropathology. PMID:21465240

  13. Arsenic Attenuates GLI Signaling, Increasing or Decreasing its Transcriptional Program in a Context-Dependent Manner

    PubMed Central

    Li, Bin; Giambelli, Camilla; Tang, Bo; Winterbottom, Emily; Long, Jun; Jin, Ke; Wang, Zhiqiang; Fei, Dennis Liang; Nguyen, Dao M.; Athar, Mohammad; Wang, Baolin; Subbarayan, Pochi R.; Wang, Lily; Rai, Priyamvada; Ardalan, Bach; Capobianco, Anthony J.

    2016-01-01

    The metalloid arsenic is a worldwide environmental toxicant, exposure to which is associated with many adverse outcomes. Arsenic is also an effective therapeutic agent in certain disease settings. Arsenic was recently shown to regulate the activity of the Hedgehog (HH) signal transduction pathway, and this regulation of HH signaling was proposed to be responsible for a subset of arsenic’s biologic effects. Surprisingly, these separate reports proposed contradictory activities for arsenic, as either an agonist or antagonist of HH signaling. Here we provide in vitro and in vivo evidence that arsenic acts as a modulator of the activity of the HH effector protein glioma-associated oncogene family zinc finger (GLI), activating or inhibiting GLI activity in a context-dependent manner. This arsenic-induced modulation of HH signaling is observed in cultured cells, patients with colorectal cancer who have received arsenic-based therapy, and a mouse colorectal cancer xenograft model. Our results show that arsenic activates GLI signaling when the intrinsic GLI activity is low but inhibits signaling in the presence of high-level GLI activity. Furthermore, we show that this modulation occurs downstream of primary cilia, evidenced by experiments in suppressor of fused homolog (SUFU) deficient cells. Combining our findings with previous reports, we present an inclusive model in which arsenic plays dual roles in GLI signaling modulation: when GLIs are primarily in their repressor form, arsenic antagonizes their repression capacity, leading to low-level GLI activation, but when GLIs are primarily in their activator form, arsenic attenuates their activity. PMID:26573582

  14. Human iPS Cell-Derived Neurons Uncover the Impact of Increased Ras Signaling in Costello Syndrome

    PubMed Central

    Rooney, Gemma E.; Goodwin, Alice F.; Depeille, Philippe; Sharir, Amnon; Schofield, Claude M.; Yeh, Erika; Roose, Jeroen P.; Klein, Ophir D.; Rauen, Katherine A.; Weiss, Lauren A.

    2016-01-01

    Increasing evidence implicates abnormal Ras signaling as a major contributor in neurodevelopmental disorders, yet how such signaling causes cortical pathogenesis is unknown. We examined the consequences of aberrant Ras signaling in the developing mouse brain and uncovered several critical phenotypes, including increased production of cortical neurons and morphological deficits. To determine whether these phenotypes are recapitulated in humans, we generated induced pluripotent stem (iPS) cell lines from patients with Costello syndrome (CS), a developmental disorder caused by abnormal Ras signaling and characterized by neurodevelopmental abnormalities, such as cognitive impairment and autism. Directed differentiation toward a neuroectodermal fate revealed an extended progenitor phase and subsequent increased production of cortical neurons. Morphological analysis of mature neurons revealed significantly altered neurite length and soma size in CS patients. This study demonstrates the synergy between mouse and human models and validates the use of iPS cells as a platform to study the underlying cellular pathologies resulting from signaling deficits. SIGNIFICANCE STATEMENT Increasing evidence implicates Ras signaling dysfunction as a major contributor in psychiatric and neurodevelopmental disorders, such as cognitive impairment and autism, but the underlying cortical cellular pathogenesis remains unclear. This study is the first to reveal human neuronal pathogenesis resulting from abnormal Ras signaling and provides insights into how these phenotypic abnormalities likely contribute to neurodevelopmental disorders. We also demonstrate the synergy between mouse and human models, thereby validating the use of iPS cells as a platform to study underlying cellular pathologies resulting from signaling deficits. Recapitulating human cellular pathologies in vitro facilitates the future high throughput screening of potential therapeutic agents that may reverse phenotypic and

  15. Actions of Thyroid Hormone Analogues on Chemokines

    PubMed Central

    Glinsky, Gennadi V.

    2016-01-01

    The extracellular domain of plasma membrane integrin αvβ3 contains a receptor for thyroid hormone (L-thyroxine, T4; 3,5,3′-triiodo-L-thyronine, T3); this receptor also binds tetraiodothyroacetic acid (tetrac), a derivative of T4. Tetrac inhibits the binding of T4 and T3 to the integrin. Fractalkine (CX3CL1) is a chemokine relevant to inflammatory processes in the CNS that are microglia-dependent but also important to normal brain development. Expression of the CX3CL1 gene is downregulated by tetrac, suggesting that T4 and T3 may stimulate fractalkine expression. Independently of its specific receptor (CX3CR1), fractalkine binds to αvβ3 at a site proximal to the thyroid hormone-tetrac receptor and changes the physical state of the integrin. Tetrac also affects expression of the genes for other CNS-relevant chemokines, including CCL20, CCL26, CXCL2, CXCL3, and CXCL10. The chemokine products of these genes are important to vascularity of the brain, particularly of the choroid plexus, to inflammatory processes in the CNS and, in certain cases, to neuroprotection. Thyroid hormones are known to contribute to regulation of each of these CNS functions. We propose that actions of thyroid hormone and hormone analogues on chemokine gene expression contribute to regulation of inflammatory processes in brain and of brain blood vessel formation and maintenance. PMID:27493972

  16. C2-domain mediated nano-cluster formation increases calcium signaling efficiency

    PubMed Central

    Bonny, Mike; Hui, Xin; Schweizer, Julia; Kaestner, Lars; Zeug, André; Kruse, Karsten; Lipp, Peter

    2016-01-01

    Conventional protein kinase Cs (cPKCs) are key signaling proteins for transducing intracellular Ca2+ signals into downstream phosphorylation events. However, the lifetime of individual membrane-bound activated cPKCs is an order of magnitude shorter than the average time needed for target-protein phosphorylation. Here, we employed intermolecular Förster resonance energy transfer (FRET) in living cells combined with computational analysis to study the spatial organization of cPKCs bound to the plasma membrane. We discovered Ca2+-dependent cPKC nano-clusters that significantly extend cPKC’s plasma-membrane residence time. These protein patterns resulted from self-assembly mediated by Ca2+-binding C2-domains, which are widely used for membrane-targeting of Ca2+-sensing proteins. We also established clustering of other unrelated C2-domain containing proteins, suggesting that nano-cluster formation is a key step for efficient cellular Ca2+-signaling. PMID:27808106

  17. C2-domain mediated nano-cluster formation increases calcium signaling efficiency.

    PubMed

    Bonny, Mike; Hui, Xin; Schweizer, Julia; Kaestner, Lars; Zeug, André; Kruse, Karsten; Lipp, Peter

    2016-11-03

    Conventional protein kinase Cs (cPKCs) are key signaling proteins for transducing intracellular Ca(2+) signals into downstream phosphorylation events. However, the lifetime of individual membrane-bound activated cPKCs is an order of magnitude shorter than the average time needed for target-protein phosphorylation. Here, we employed intermolecular Förster resonance energy transfer (FRET) in living cells combined with computational analysis to study the spatial organization of cPKCs bound to the plasma membrane. We discovered Ca(2+)-dependent cPKC nano-clusters that significantly extend cPKC's plasma-membrane residence time. These protein patterns resulted from self-assembly mediated by Ca(2+)-binding C2-domains, which are widely used for membrane-targeting of Ca(2+)-sensing proteins. We also established clustering of other unrelated C2-domain containing proteins, suggesting that nano-cluster formation is a key step for efficient cellular Ca(2+)-signaling.

  18. Chemokines and Chemokine Receptors in Susceptibility to HIV-1 Infection and Progression to AIDS

    PubMed Central

    Chatterjee, Animesh; Rathore, Anurag; Vidyant, Sanjukta; Kakkar, Kavita; Dhole, Tapan N.

    2012-01-01

    A multitude of host genetic factors plays a crucial role in susceptibility to HIV-1 infection and progression to AIDS, which is highly variable among individuals and populations. This review focuses on the chemokine-receptor and chemokine genes, which were extensively studied because of their role as HIV co-receptor or co-receptor competitor and influences the susceptibility to HIV-1 infection and progression to AIDS in HIV-1 infected individuals. PMID:22377730

  19. Chemokine guided angiogenesis directs coronary vasculature formation in zebrafish

    PubMed Central

    Harrison, Michael R.M.; Bussmann, Jeroen; Huang, Ying; Zhao, Long; Osorio, Arthela; Burns, C. Geoffrey; Burns, Caroline E.; Sucov, Henry M.; Siekmann, Arndt F.; Lien, Ching-Ling

    2015-01-01

    SUMMARY Interruption of coronary blood supply severely impairs heart function with often-fatal consequences for heart disease patients. However the formation and maturation of these coronary vessels is not fully understood. Here we provide a detailed analysis of coronary vessel development in zebrafish. We observe that coronary vessels form in zebrafish by angiogenic sprouting of arterial cells derived from the endocardium at the atrioventricular canal. Endothelial cells express the CXC-motif chemokine receptor Cxcr4a and migrate to vascularize the ventricle under the guidance of the myocardium-expressed ligand Cxcl12b. cxcr4a mutant zebrafish fail to form a vascular network, whereas ectopic expression of Cxcl12b ligand induces coronary vessel formation. Importantly, cxcr4a mutant zebrafish fail to undergo heart regeneration following injury. Our results suggest that chemokine-signaling has an essential role in coronary vessel formation by directing migration of endocardium-derived endothelial cells. Poorly developed vasculature in cxcr4a mutants likely underlies decreased regenerative potential in adults. PMID:26017769

  20. Antimicrobial effects of interferon-inducible CXC chemokines against Bacillus anthracis spores and bacilli.

    PubMed

    Crawford, Matthew A; Zhu, Yinghua; Green, Candace S; Burdick, Marie D; Sanz, Patrick; Alem, Farhang; O'Brien, Alison D; Mehrad, Borna; Strieter, Robert M; Hughes, Molly A

    2009-04-01

    Based on previous studies showing that host chemokines exert antimicrobial activities against bacteria, we sought to determine whether the interferon-inducible Glu-Leu-Arg-negative CXC chemokines CXCL9, CXCL10, and CXCL11 exhibit antimicrobial activities against Bacillus anthracis. In vitro analysis demonstrated that all three CXC chemokines exerted direct antimicrobial effects against B. anthracis spores and bacilli including marked reductions in spore and bacillus viability as determined using a fluorometric assay of bacterial viability and CFU determinations. Electron microscopy studies revealed that CXCL10-treated spores failed to undergo germination as judged by an absence of cytological changes in spore structure that occur during the process of germination. Immunogold labeling of CXCL10-treated spores demonstrated that the chemokine was located internal to the exosporium in association primarily with the spore coat and its interface with the cortex. To begin examining the potential biological relevance of chemokine-mediated antimicrobial activity, we used a murine model of inhalational anthrax. Upon spore challenge, the lungs of C57BL/6 mice (resistant to inhalational B. anthracis infection) had significantly higher levels of CXCL9, CXCL10, and CXCL11 than did the lungs of A/J mice (highly susceptible to infection). Increased CXC chemokine levels were associated with significantly reduced levels of spore germination within the lungs as determined by in vivo imaging. Taken together, our data demonstrate a novel antimicrobial role for host chemokines against B. anthracis that provides unique insight into host defense against inhalational anthrax; these data also support the notion for an innovative approach in treating B. anthracis infection as well as infections caused by other spore-forming organisms.

  1. Hepatic insulin signaling changes: possible mechanism in prenatal hypoxia-increased susceptibility of fatty liver in adulthood.

    PubMed

    Cao, Li; Mao, Caiping; Li, Shigang; Zhang, Yujuan; Lv, Juanxiu; Jiang, Shan; Xu, Zhice

    2012-10-01

    Nonalcoholic fatty liver disease (NAFLD) is strongly linked to insulin resistance. Prenatal hypoxia (PH) is a risk factor in programming of insulin resistance, glucose intolerance, and metabolic dysfunctions in later life, although the mechanisms are unclear. In this study, the role of metabolic and histological changes as well as the hepatic insulin signaling mechanisms were determined in increasing susceptibility of NAFLD in the fetus and offspring exposed to PH. Pregnant rats exposed to hypoxia (O(2) 10%) during pregnancy demonstrated decreased fetal body and liver weight as well as liver to body weight ratio, whereas these changes were not observed in the offspring. However, male liver to body weight ratio increased after PH stress. Microscopic analysis demonstrated that exposure to PH resulted in distorted architecture of the hepatic parenchyma cells with reduced cellularity in the fetus and offspring. Blood glucose and insulin levels were lower with enhanced insulin sensitivity and increased expression of hepatic insulin-signaling elements in the fetus. Furthermore, insulin resistance, impaired glucose homeostasis, and altered expression of insulin-signaling elements occurred in the offspring. Postnatal hypoxia increased hepatic lipid droplets and triglyceride in liver, whereas expressions of insulin-signaling elements were less in the offspring exposed to PH except glucose transporters 2. The results indicated that PH contributed to hepatocyte heteroplasia and metabolic changes that enhanced vulnerability for NAFLD in the offspring, probably via affecting insulin signaling pathway, including glucose transporters 2.

  2. Chronically Increased G[subscript s][alpha] Signaling Disrupts Associative and Spatial Learning

    ERIC Educational Resources Information Center

    Bourtchouladze, Rusiko; Patterson, Susan L.; Kelly, Michele P.; Kreibich, Arati; Kandel, Eric R.; Abel, Ted

    2006-01-01

    The cAMP/PKA pathway plays a critical role in learning and memory systems in animals ranging from mice to "Drosophila" to "Aplysia." Studies of olfactory learning in "Drosophila" suggest that altered expression of either positive or negative regulators of the cAMP/PKA signaling pathway beyond a certain optimum range may be deleterious. Here we…

  3. Zearalenone Increases Reproductive Tract Development, but not Skeletal Muscle Signaling in Prepubertal Gilts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Zearalenone (zea) is a potent mycotoxin that has estrogenic properties. In vitro results indicate that zea metabolites are capable of down-regulating proteins associated with protein synthesis (mammalian target of rapamycin, mTOR) and cellular proliferation (extracellular signal-regulated kinase, ER...

  4. Differential chemokine expression following respiratory virus infection reflects Th1- or Th2-biased immunopathology.

    PubMed

    Culley, Fiona J; Pennycook, Alasdair M J; Tregoning, John S; Hussell, Tracy; Openshaw, Peter J M

    2006-05-01

    Respiratory syncytial virus (RSV) is a major viral pathogen of infants that also reinfects adults. During RSV infection, inflammatory host cell recruitment to the lung plays a central role in determining disease outcome. Chemokines mediate cell recruitment to sites of inflammation and are influenced by, and influence, the production of cytokines. We therefore compared chemokine production in a mouse model of immunopathogenic RSV infection in which either Th1 or Th2 immunopathology is induced by prior sensitization to individual RSV proteins. Chemokine expression profiles were profoundly affected by the nature of the pulmonary immunopathology: "Th2" immunopathology in BALB/c mice was associated with increased and prolonged expression of CCL2 (MCP-1), CXCL10 (IP-10), and CCL11 (eotaxin) starting within 24 h of challenge. C57BL/6 mice with "Th2" pathology (enabled by a deficiency of CD8+ cells) also showed increased CCL2 production. No differences in chemokine receptor expression were detected. Chemokine blockers may therefore be of use for children with bronchiolitis.

  5. Chemokine-leukocyte interactions. The voodoo that they do so well.

    PubMed

    Taub, D D

    1996-12-01

    Leukocyte recruitment from the circulation into inflammatory tissues requires a series of soluble and cell-bound signals between the responding leukocyte and vascular endothelial barrier. Chemotactic factors are believed to be responsible for this selective adhesion and transmigration. A superfamily of small, soluble, structurally-related molecules called 'chemokines' have been identified and shown to selectively promote the rapid adhesion and chemotaxis of a variety of leukocyte subtypes both in vivo and in vitro. Chemokines are produced by almost every cell type in the body in response to a number of inflammatory signals, in particular those which activate leukocyte-endothelial cell interactions. These molecules also appear to play important roles in hematopoesis, cellular activation, and leukocyte effector functions. In addition, chemokines have been found in the tissues of a variety of disease states characterized by distinct leukocytic infiltrates, including rheumatoid arthritis, sepsis, atherosclerosis, asthma, psoriasis, ischemia/reperfusion injury, HIV replication, and a variety of pulmonary disease states. This review will primarily focus on the role of chemokines in cell adhesion and trafficking as well as their role as effector molecules.

  6. Exercise increases insulin signaling in the hippocampus: physiological effects and pharmacological impact of intracerebroventricular insulin administration in mice.

    PubMed

    Muller, Alexandre P; Gnoatto, Jussânia; Moreira, Julia D; Zimmer, Eduardo R; Haas, Clarissa B; Lulhier, Francisco; Perry, Marcos L S; Souza, Diogo O; Torres-Aleman, Ignácio; Portela, Luis V

    2011-10-01

    Increasing evidence indicates that physical exercise induces adaptations at the cellular, molecular, and systemic levels that positively affect the brain. Insulin plays important functional roles within the brain that are mediated by insulin-receptor (IR) signaling. In the hippocampus, insulin improves synaptic plasticity, memory formation, and learning via direct modulation of GABAergic and glutamatergic receptors. Separately, physical exercise and central insulin administration exert relevant roles in cognitive function. We here use CF1 mice to investigate (i) the effects of voluntary exercise on hippocampal insulin signaling and memory performance and (ii) whether central insulin administration alters the effects of exercise on hippocampal insulin signaling and memory performance. Adult mice performed 30 days of voluntary exercise on running wheel and afterward both, sedentary and exercised groups, received intracerebroventricular (icv) injection of saline or insulin (0.5-5 mU). Memory performance was assessed using the inhibitory avoidance and water maze tasks. Hippocampal tissue was measured for [U-(14)C] glucose oxidation and the immunocontent of insulin receptor/signaling (IR, pTyr, pAktser473). Additionally, the phosphorylation of the glutamate NMDA receptor NR2B subunit and the capacity of glutamate uptake were measured, and immunohistochemistry was used to determine glial reactivity. Exercise significantly increased insulin peripheral sensitivity, spatial learning, and hippocampal IR/pTyrIR/pAktser473 immunocontent. Glucose oxidation, glutamate uptake, and astrocyte number also increased relative to the sedentary group. In both memory tasks, 5 mU icv insulin produced amnesia but only in exercised animals. This amnesia was associated a rapid (15 min) and persistent (24 h) increase in hippocampal pNR2B immunocontent that paralleled the increase in glial reactivity. In conclusion, physical exercise thus increased hippocampal insulin signaling and improved

  7. Tumor microenvironment B cells increase bladder cancer metastasis via modulation of the IL-8/androgen receptor (AR)/MMPs signals.

    PubMed

    Ou, Zhenyu; Wang, Yongjie; Liu, Longfei; Li, Lei; Yeh, Shuyuan; Qi, Lin; Chang, Chawnshang

    2015-09-22

    While B cells in the tumor microenvironment may play important roles in cancer progression, their impacts on the bladder cancer (BCa) metastasis remain unclear. Here we found from human clinical BCa samples that BCa tissues could recruit more B cells than the surrounding normal bladder tissues and the in vitro co-culture assay also demonstrated that B cells could be recruited more easily towards BCa cells compared to normal bladder cells. Chamber invasion and 3D invasion assays showed the recruited B cells could then significantly increase the BCa cell invasion. Mechanism dissection found that recruited B cells could increase IL-8/androgen receptor (AR) signals in BCa cells that could then promote the expression of metastasis genes including MMP1 and MMP13. Blocking the IL-8/AR/MMPs signals either by anti-IL-8 neutralizing antibody, AR-siRNA, or MMPs inhibitors all partially reversed the infiltrating B cells capacity to increase the BCa cell invasion. The in vivo data from orthotopically xenografted BCa mouse model also confirmed that infiltrating B cells could increase BCa cell invasion via increasing AR signals. Together, these results demonstrate the key roles of B cells within the bladder tumor microenvironment that increase the BCa metastasis and may help us to develop the potential therapies via targeting these newly identified IL-8/AR/MMPs signals to better battle the BCa progression.

  8. Expression of cell adhesion molecules, chemokines and chemokine receptors involved in leukocyte traffic in rats undergoing autoimmune orchitis.

    PubMed

    Guazzone, V A; Jacobo, P; Denduchis, B; Lustig, L

    2012-05-01

    The testis is considered an immunologically privileged site where germ cell antigens are protected from autoimmune attack. Yet in response to infections, inflammatory diseases, or trauma, there is an influx of leukocytes to testicular interstitium. Interactions between endothelial cells (EC) and circulating leukocytes are implicated in the initiation and evolution of inflammatory processes. Chemokines are a family of chemoattractant cytokines characterized by their ability to both recruit and activate cells. Thus, we investigated the expression of CCL3, its receptors, and adhesion molecules CD31 and CD106 in an in vivo model of experimental autoimmune orchitis (EAO). In EAO, the highest content of CCL3 in testicular fluid coincides with onset of the disease. However, CCL3 released in vitro by testicular macrophages is higher during the immunization period. The specific chemokine receptors, CCR1 and CCR5, were expressed by testicular monocytes/macrophages and an increased number of CCR5+ cells was associated with the degree of testicular lesion. EC also play an essential role by facilitating leukocyte recruitment via their ability to express cell surface adhesion molecules that mediate interactions with leukocytes in the bloodstream. Rats with EAO showed a significant increase in the percentage of CD31+ EC that upregulate the expression of CD106. The percentage of leukocytes isolated from peripheral blood and lymph nodes expressing CD49d (CD106 ligand) also increases during orchitis. These data suggest that cell adhesion molecules, in conjunction with chemokines, contribute to the formation of a chemotactic gradient within the testis, causing the leukocyte infiltration characteristic of EAO histopathology.

  9. Pathophysiological roles of chemokines in human reproduction: an overview.

    PubMed

    Kitaya, Kotaro; Yamada, Hisao

    2011-05-01

    Chemokines are a group of small cytokines that have an ability to induce leukocyte migration. Chemokines exert their functions by binding and activating specific G protein-coupled receptors. Studies have unveiled pleiotropic bioactivities of chemokines in various phenomena ranging from immunomodulation, embryogenesis, and homeostasis to pathogenesis. In the mammalian reproductive system, chemokines unexceptionally serve in multimodal events that are closely associated with establishment, maintenance, and deterioration of fecundity. The aim of this review is to update the knowledge on chemokines in male and female genital organs, with a focus on their potential pathophysiological roles in human reproduction.

  10. The chemotaxis of M1 and M2 macrophages is regulated by different chemokines.

    PubMed

    Xuan, Wenjuan; Qu, Qing; Zheng, Biao; Xiong, Sidong; Fan, Guo-Huang

    2015-01-01

    The homing of proinflammatory (M1) and the "alternatively activated" anti-inflammatory (M2) macrophages plays a different role in the process of inflammation. Chemokines are the major mediators of macrophage chemotaxis, but how they differentially regulate M1 and M2 macrophages remains largely unclear. In the present study, we attempted to screen chemokines that differentially induce chemotaxis of M1 and M2 macrophages and to explore the underlying mechanism. Among the 41 chemokines that specifically bind to 20 chemokine receptors, CCL19, CCL21, CCL24, CCL25, CXCL8, CXCL10, and XCL2 specifically induced M1 macrophage chemotaxis, whereas CCL7 induced chemotaxis of both M1 and M2 macrophages. Whereas the differential effects of these chemokines on M1/M2 macrophage chemotaxis could be attributable to the predominant expression of their cognate receptors on the macrophage subsets, CCR7, the receptor for CCL19/CCL21, appeared to be an exception. Immunoblot analysis indicated an equivalent level of CCR7 in the whole cell lysate of M1 and M2 macrophages, but CCL19 and CCL21 only induced M1 macrophage chemotaxis. Both immunoblot and confocal microscopy analyses demonstrated that CCR7 was predominantly expressed on the cell surface of M1 but in the cytosol of M2 macrophages before ligand stimulation. As a result, CCL19 or CCL21 induced activation of both MEK1-ERK1/2 and PI3K-AKT cascades in M1 but not in M2 macrophages. Intriguingly, CCL19/CCL21-mediated M1 macrophage chemotaxis was blocked by specific inhibition of PI3K rather than MEK1. Together, these findings suggest that recruitment of M1 and M2 macrophages is fine tuned by different chemokines with the involvement of specific signaling pathways.

  11. Inhibition of Auxin Signaling in Frankia Species-Infected Cells in Casuarina glauca Nodules Leads to Increased Nodulation1

    PubMed Central

    Champion, Antony; Lucas, Mikael; Tromas, Alexandre; Vaissayre, Virginie; Crabos, Amandine; Diédhiou, Issa; Prodjinoto, Hermann; Moukouanga, Daniel; Pirolles, Elodie; Cissoko, Maïmouna; Bonneau, Jocelyne; Gherbi, Hassen; Franche, Claudine; Hocher, Valérie; Svistoonoff, Sergio; Laplaze, Laurent

    2015-01-01

    Actinorhizal symbioses are mutualistic interactions between plants and the soil bacteria Frankia spp. that lead to the formation of nitrogen-fixing root nodules. The plant hormone auxin has been suggested to play a role in the mechanisms that control the establishment of this symbiosis in the actinorhizal tree Casuarina glauca. Here, we analyzed the role of auxin signaling in Frankia spp.-infected cells. Using a dominant-negative version of an endogenous auxin-signaling regulator, INDOLE-3-ACETIC ACID7, we established that inhibition of auxin signaling in these cells led to increased nodulation and, as a consequence, to higher nitrogen fixation per plant even if nitrogen fixation per nodule mass was similar to that in the wild type. Our results suggest that auxin signaling in Frankia spp.-infected cells is involved in the long-distance regulation of nodulation in actinorhizal symbioses. PMID:25627215

  12. Vav1 and Rac Control Chemokine-promoted T Lymphocyte Adhesion Mediated by the Integrin α4β1D⃞

    PubMed Central

    García-Bernal, David; Wright, Natalia; Sotillo-Mallo, Elena; Nombela-Arrieta, César; Stein, Jens V.; Bustelo, Xosé R.; Teixidó, Joaquin

    2005-01-01

    The chemokine CXCL12 promotes T lymphocyte adhesion mediated by the integrin α4β1. CXCL12 activates the GTPase Rac, as well as Vav1, a guanine-nucleotide exchange factor for Rac, concomitant with up-regulation of α4β1-dependent adhesion. Inhibition of CXCL12-promoted Rac and Vav1 activation by transfection of dominant negative Rac or Vav1 forms, or by transfection of their siRNA, remarkably impaired the increase in T lymphocyte attachment to α4β1 ligands in response to this chemokine. Importantly, inhibition of Vav1 expression by RNA interference resulted in a blockade of Rac activation in response to CXCL12. Adhesions in flow chambers and soluble binding assays using these transfectants indicated that initial ligand binding and adhesion strengthening mediated by α4β1 were dependent on Vav1 and Rac activation by CXCL12. Finally, CXCL12-promoted T-cell transendothelial migration involving α4β1-mediated adhesion was notably inhibited by expression of dominant negative Vav1 and Rac. These results indicate that activation of Vav1-Rac signaling pathway by CXCL12 represents an important inside-out event controlling efficient up-regulation of α4β1-dependent T lymphocyte adhesion. PMID:15872091

  13. Increased CRF signalling in a ventral tegmental area-interpeduncular nucleus-medial habenula circuit induces anxiety during nicotine withdrawal.

    PubMed

    Zhao-Shea, Rubing; DeGroot, Steven R; Liu, Liwang; Vallaster, Markus; Pang, Xueyan; Su, Qin; Gao, Guangping; Rando, Oliver J; Martin, Gilles E; George, Olivier; Gardner, Paul D; Tapper, Andrew R

    2015-04-21

    Increased anxiety is a prominent withdrawal symptom in abstinent smokers, yet the neuroanatomical and molecular bases underlying it are unclear. Here we show that withdrawal-induced anxiety increases activity of neurons in the interpeduncular intermediate (IPI), a subregion of the interpeduncular nucleus (IPN). IPI activation during nicotine withdrawal was mediated by increased corticotropin releasing factor (CRF) receptor-1 expression and signalling, which modulated glutamatergic input from the medial habenula (MHb). Pharmacological blockade of IPN CRF1 receptors or optogenetic silencing of MHb input reduced IPI activation and alleviated withdrawal-induced anxiety; whereas IPN CRF infusion in mice increased anxiety. We identified a mesointerpeduncular circuit, consisting of ventral tegmental area (VTA) dopaminergic neurons projecting to the IPN, as a potential source of CRF. Knockdown of CRF synthesis in the VTA prevented IPI activation and anxiety during nicotine withdrawal. These data indicate that increased CRF receptor signalling within a VTA-IPN-MHb circuit triggers anxiety during nicotine withdrawal.

  14. Platelet-derived chemokines: pathophysiology and therapeutic aspects.

    PubMed

    Flad, Hans-Dieter; Brandt, Ernst

    2010-07-01

    The identification of chemokines in blood platelets has strengthened our view of these cells as participants in immune host defense. Platelet chemokines representing prestored and rapidly releasable proteins may play a major role as first-line inflammatory mediators. This is evident from their capability to recruit early inflammatory cells such as neutrophil granulocytes and monocytes and even to exhibit direct antimicrobial activity. However, insight is growing that platelet chemokines may be also long-term regulators, e.g., by activating T lymphocytes, by modulating the formation of endothelium and even thrombocytopoiesis itself. This review deals with the individual and cooperative functionality of platelet chemokines, as well as their potential as a basis for therapeutic intervention in the pathology of inflammation, infection, allergy and tumors. Within this context, therapeutic strategies based on the use of antibodies, modified chemokines, chemokine-binding proteins and chemokine receptor antagonists as well as first clinical studies will be addressed.

  15. Cloning and characterization of exodus, a novel beta-chemokine.

    PubMed

    Hromas, R; Gray, P W; Chantry, D; Godiska, R; Krathwohl, M; Fife, K; Bell, G I; Takeda, J; Aronica, S; Gordon, M; Cooper, S; Broxmeyer, H E; Klemsz, M J

    1997-05-01

    Chemokines are a family of related proteins that regulate leukocyte infiltration into inflamed tissue. Some chemokines such as MIP-1 alpha also inhibit hematopoietic progenitor cell proliferation. Recently, three chemokines, MIP-1 alpha, MIP-1 beta, and RANTES, have been found to significantly decrease human immunodeficiency virus production from infected T cells. We report here the cloning and characterization of a novel human chemokine termed Exodus for its chemotactic properties. This novel chemokine is distantly related to other chemokines (28% homology with MIP-1 alpha) and shares several biological activities. Exodus is expressed preferentially in lymphocytes and monocytes, and its expression is markedly upregulated by mediators of inflammation such as tumor necrosis factor or lipopolysaccharide. Purified synthetic Exodus was found to inhibit proliferation of myeloid progenitors in colony formation assays. Exodus also stimulated chemotaxis of peripheral blood mononuclear cells. The sequence homology, expression, and biological activity indicate that Exodus represents a novel divergent beta-chemokine.

  16. Regulation of pulmonary fibrosis by chemokine receptor CXCR3

    PubMed Central

    Jiang, Dianhua; Liang, Jiurong; Hodge, Jennifer; Lu, Bao; Zhu, Zhou; Yu, Shuang; Fan, Juan; Gao, Yunfei; Yin, Zhinan; Homer, Robert; Gerard, Craig; Noble, Paul W.

    2004-01-01

    CXC chemokine receptor 3 (CXCR3) is the receptor for the IFN-γ–inducible C-X-C chemokines MIG/CXCL9, IP-10/CXCL10, and I-TAC/CXCL11. CXCR3 is expressed on activated immune cells and proliferating endothelial cells. The role of CXCR3 in fibroproliferation has not been investigated. We examined the role of CXCR3 in pulmonary injury and repair in vivo. CXCR3-deficient mice demonstrated increased mortality with progressive interstitial fibrosis relative to WT mice. Increased fibrosis occurred without increased inflammatory cell recruitment. CXCR3 deficiency resulted in both a reduced early burst of IFN-γ production and decreased expression of CXCL10 after lung injury. We identified a relative deficiency in lung NK cells in the unchallenged CXCR3-deficient lung and demonstrated production of IFN-γ by WT lung NK cells in vivo following lung injury. The fibrotic phenotype in the CXCR3-deficient mice was significantly reversed following administration of exogenous IFN-γ or restoration of endogenous IFN-γ production by adoptive transfer of WT lymph node and spleen cells. Finally, pretreatment of WT mice with IFN-γ–neutralizing Ab’s enhanced fibrosis following lung injury. These data demonstrate a nonredundant role for CXCR3 in limiting tissue fibroproliferation and suggest that this effect may be mediated, in part, by the innate production of IFN-γ following lung injury. PMID:15254596

  17. Heterologous desensitization of opioid receptors by chemokines inhibits chemotaxis and enhances the perception of pain.

    PubMed

    Szabo, Imre; Chen, Xiao-Hong; Xin, Li; Adler, Martin W; Howard, O M Z; Oppenheim, Joost J; Rogers, Thomas J

    2002-08-06

    The chemokines use G protein-coupled receptors to regulate the migratory and proadhesive responses of leukocytes. Based on observations that G protein-coupled receptors undergo heterologous desensitization, we have examined the ability of chemokines to also influence the perception of pain by cross-desensitizing opioid G protein-coupled receptors function in vitro and in vivo. We find that the chemotactic activities of both mu- and delta-opioid receptors are desensitized following activation of the chemokine receptors CCR5, CCR2, CCR7, and CXCR4 but not of the CXCR1 or CXCR2 receptors. Furthermore, we also find that pretreatment with RANTES/CCL5, the ligand for CCR1, and CCR5 or SDF-1alpha/CXCL12, the ligand for CXCR4, followed by opioid administration into the periaqueductal gray matter of the brain results in an increased rat tail flick response to a painful stimulus. Because chemokine administration into the periaqueductal gray matter inhibits opioid-induced analgesia, we propose that the activation of proinflammatory chemokine receptors down-regulates the analgesic functions of opioid receptors, and this enhances the perception of pain at inflammatory sites.

  18. Toll-like receptor signaling increases production of 1,25-dihydroxyvitamin D3 in bovine macrophages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Activation of macrophages can occur through Toll-like receptor (TLR) recognition of pathogen associated molecular patterns (PAMP). Recently, it has been discovered that TLR signaling can increase 1alpha-hydroxylase (Cyp27B1) expression in human and mouse macrophages. The enzymatic activity of 1alp...

  19. Food deprivation reduces and leptin increases the amplitude of an active sensory and communication signal in a weakly electric fish.

    PubMed

    Sinnett, Philip M; Markham, Michael R

    2015-05-01

    Energetic demands of social communication signals can constrain signal duration, repetition, and magnitude. The metabolic costs of communication signals are further magnified when they are coupled to active sensory systems that require constant signal generation. Under such circumstances, metabolic stress incurs additional risk because energy shortfalls could degrade sensory system performance as well as the social functions of the communication signal. The weakly electric fish Eigenmannia virescens generates electric organ discharges (EODs) that serve as both active sensory and communication signals. These EODs are maintained at steady frequencies of 200-600Hz throughout the lifespan, and thus represent a substantial metabolic investment. We investigated the effects of metabolic stress (food deprivation) on EOD amplitude (EODa) and EOD frequency (EODf) in E. virescens and found that only EODa decreases during food deprivation and recovers after restoration of feeding. Cortisol did not alter EODa under any conditions, and plasma cortisol levels were not changed by food deprivation. Both melanocortin hormones and social challenges caused transient EODa increases in both food-deprived and well-fed fish. Intramuscular injections of leptin increased EODa in food-deprived fish but not well-fed fish, identifying leptin as a novel regulator of EODa and suggesting that leptin mediates EODa responses to metabolic stress. The sensitivity of EODa to dietary energy availability likely arises because of the extreme energetic costs of EOD production in E. virescens and also could reflect reproductive strategies of iteroparous species that reduce social signaling and reproduction during periods of stress to later resume reproductive efforts when conditions improve.

  20. Biallelic expression of Tbx1 protects the embryo against developmental defects caused by increased Receptor Tyrosine Kinase signalling

    PubMed Central

    Simrick, Subreena; Szumska, Dorota; Gardiner, Jennifer R.; Jones, Kieran; Sagar, Karun; Morrow, Bernice; Bhattacharya, Shoumo; Basson, M. Albert

    2014-01-01

    Background 22q11.2 deletion syndrome (22q11DS) is the most common microdeletion syndrome in humans, characterised by cardiovascular defects such as interrupted aortic arch, outflow tract defects, thymus and parathyroid hypo- or aplasia and cleft palate. Heterozygosity of Tbx1, the mouse homologue of the candidate TBX1 gene, results in mild defects dependent on genetic background, whereas complete inactivation results in severe malformations in multiple tissues. Results The loss of function mutations in two Sprouty genes, which encode feedback antagonists of receptor tyrosine kinase (RTK) signaling, phenocopy many defects associated with the syndrome in the mouse. The stepwise reduction of Sprouty gene dosage resulted in different phenotypes emerging at specific steps, suggesting that the threshold up to which a given developmental process can tolerate increased RTK signaling is different. Tbx1 heterozygosity significantly exacerbated the severity of all these defects, which correlated with a substantial increase in RTK signaling. Conclusions Our findings suggest that TBX1 functions as an essential component of a mechanism that protects the embryo against perturbations in RTK signaling that may lead to developmental defects characteristic of 22q11.2 deletion syndrome. We propose that genetic factors that enhance RTK signalling ought to be considered as potential genetic modifiers of this syndrome. PMID:22674535

  1. PGRN haploinsufficiency increased Wnt5a signaling in peripheral cells from frontotemporal lobar degeneration-progranulin mutation carriers.

    PubMed

    Alquézar, Carolina; Esteras, Noemí; de la Encarnación, Ana; Alzualde, Ainhoa; Moreno, Fermín; López de Munain, Adolfo; Martín-Requero, Angeles

    2014-04-01

    Loss-of-function progranulin (PGRN) mutations have been identified as the major cause of frontotemporal lobar degeneration with TDP-43 protein inclusions (FTLD-TDP). Previously, we reported cell cycle-related alterations in lymphoblasts from FTLD-TDP patients, carrying the c.709-1G>A null PGRN mutation, suggesting aberrant cell cycle activation in affected neurons. Here we report that PGRN haploinsufficiency activates the extracellular signal-regulated protein kinases 1 and 2 pathway in a Ca(2+), protein kinase C-dependent, and pertussis toxin-sensitive manner. Addition of exogenous PGRN or conditioned medium from control cells normalized the response of PGRN-deficient lymphoblasts to serum activation. Our data indicated that noncanonical Wnt5a signaling might be overactivated by PGRN deficiency. We detected increased cellular and secreted levels of Wnt5a in PGRN-deficient lymphoblasts associated with enhanced phosphorylated calmodulin kinase II. Moreover, treatment of control cells with exogenous Wingless-type 5a (Wnt5a)-activated Ca(2+)/calmodulin kinase II (CaMKII), increased extracellular signal-regulated protein kinases 1 and 2 activity and cell proliferation up to the levels found in c.709-1G>A carrier cells. PGRN knockdown SH-SY5Y neuroblastoma cells also show enhanced Wnt5a content and signaling. Taken together, our results revealed an important role of Wnt signaling in FTLD-TDP pathology and suggest a novel target for therapeutic intervention.

  2. Collision-induced signal enhancement: a method to increase product ion intensities in MS/MS and MSn experiments.

    PubMed

    Asam, M R; Ray, K L; Glish, G L

    1998-05-01

    Collision-induced signal enhancement (CISE), a new technique to enhance the MSn capabilities of the quadrupole ion trap, is demonstrated. CISE is based on the chemistry, i.e., the dissociation pathways, of the analyte examined. Polysaccharides up to hexamers are used to demonstrate the capabilities of CISE to enhance signal in two distinct functional modes. Mode 1 CISE is designed to enhance the signal of an ion desired for MSn analysis. Mode 2 CISE is designed to enhance structurally significant product ions in an MS/MS spectrum. Two different approaches can be utilized to effect the two functional modes of CISE. Both approaches use conventional resonant excitation techniques to effect dissociation, which is performed nonanalytically, i.e., without isolation of the ions to be dissociated. The two approaches are (1) single-frequency resonance excitation, and (2) broad-band wave form resonant excitation. Experimental results for Mode 1 CISE analysis demonstrate up to a 17.3-fold signal increase for the single-frequency approach and 5.3-fold using broad-band excitation. Mode 2 CISE analysis shows up to a 16.3-fold increase in signal strength with single-frequency excitation and 3.3-fold using broad-band excitation.

  3. Lipopolysaccharide-induced multinuclear cells: Increased internalization of polystyrene beads and possible signals for cell fusion

    SciTech Connect

    Nakanishi-Matsui, Mayumi Yano, Shio; Futai, Masamitsu

    2013-11-01

    Highlights: •LPS induces multinuclear cells from murine macrophage-derived RAW264.7 cells. •Large beads are internalized by cells actively fusing to become multinuclear. •The multinuclear cell formation is inhibited by anti-inflammatory cytokine, IL10. •Signal transduction for cell fusion is different from that for inflammation. -- Abstract: A murine macrophage-derived line, RAW264.7, becomes multinuclear on stimulation with lipopolysaccharide (LPS), an outer membrane component of Gram-negative bacteria. These multinuclear cells internalized more polystyrene beads than mononuclear cells or osteoclasts (Nakanishi-Matsui, M., Yano, S., Matsumoto, N., and Futai, M., 2012). In this study, we analyzed the time courses of cell fusion in the presence of large beads. They were internalized into cells actively fusing to become multinuclear. However, the multinuclear cells once formed showed only low phagocytosis activity. These results suggest that formation of the multinuclear cells and bead internalization took place simultaneously. The formation of multinuclear cells was blocked by inhibitors for phosphoinositide 3-kinase, phospholipase C, calcineurin, and c-Jun N-terminal kinase. In addition, interleukin 6 and 10 also exhibited inhibitory effects. These signaling molecules and cytokines may play a crucial role in the LPS-induced multinuclear cell formation.

  4. The effects of increased fluid viscosity on stationary characteristics of EEG signal in healthy adults.

    PubMed

    Jestrović, I; Coyle, J L; Sejdić, E

    2014-11-17

    Electroencephalography (EEG) systems can enable us to study cerebral activation patterns during performance of swallowing tasks and possibly infer about the nature of abnormal neurological conditions causing swallowing difficulties. While it is well known that EEG signals are non-stationary, there are still open questions regarding the stationarity of EEG during swallowing activities and how the EEG stationarity is affected by different viscosities of the fluids that are swallowed by subjects during these swallowing activities. In the present study, we investigated the EEG signal collected during swallowing tasks by collecting data from 55 healthy adults (ages 18-65). Each task involved the deliberate swallowing of boluses of fluids of different viscosities. Using time-frequency tests with surrogates, we showed that the EEG during swallowing tasks could be considered non-stationary. Furthermore, the statistical tests and linear regression showed that the parameters of fluid viscosity, sex, and different brain regions significantly influenced the index of non-stationarity values. Therefore, these parameters should be considered in future investigations which use EEG during swallowing activities.

  5. Increasing Notch signaling antagonizes PRC2-mediated silencing to promote reprograming of germ cells into neurons

    PubMed Central

    Seelk, Stefanie; Adrian-Kalchhauser, Irene; Hargitai, Balázs; Hajduskova, Martina; Gutnik, Silvia; Tursun, Baris; Ciosk, Rafal

    2016-01-01

    Cell-fate reprograming is at the heart of development, yet very little is known about the molecular mechanisms promoting or inhibiting reprograming in intact organisms. In the C. elegans germline, reprograming germ cells into somatic cells requires chromatin perturbation. Here, we describe that such reprograming is facilitated by GLP-1/Notch signaling pathway. This is surprising, since this pathway is best known for maintaining undifferentiated germline stem cells/progenitors. Through a combination of genetics, tissue-specific transcriptome analysis, and functional studies of candidate genes, we uncovered a possible explanation for this unexpected role of GLP-1/Notch. We propose that GLP-1/Notch promotes reprograming by activating specific genes, silenced by the Polycomb repressive complex 2 (PRC2), and identify the conserved histone demethylase UTX-1 as a crucial GLP-1/Notch target facilitating reprograming. These findings have wide implications, ranging from development to diseases associated with abnormal Notch signaling. DOI: http://dx.doi.org/10.7554/eLife.15477.001 PMID:27602485

  6. Chemokine modulation of the tumor microenvironment.

    PubMed

    Richmond, Ann

    2010-06-01

    Coverage on: Shields, J.D., Kourtis, I.C., Tomei, A.A., Roberts, J.M. & Swartz,M.A. (2010). Induction of lymphoidlike stroma and immune escape by tumors that express the chemokine CCL21. Science. E Pub, March 25, 2010; and Kim, M.Y., Oskarsson, T., Acharyya, S.,Nguyen, D.X., Zhang, X.H., Norton, L. & Massague, J. (2009). Tumor self-seeding by circulating cancer cells. Cell, 139,1315-1326.

  7. Role of chemokines and chemokine receptors in shaping the effector phase of the antitumor immune response.

    PubMed

    Franciszkiewicz, Katarzyna; Boissonnas, Alexandre; Boutet, Marie; Combadière, Christophe; Mami-Chouaib, Fathia

    2012-12-15

    Immune system-mediated eradication of neoplastic cells requires induction of a strong long-lasting antitumor T-cell response. However, generation of tumor-specific effector T cells does not necessarily result in tumor clearance. CTL must first be able to migrate to the tumor site, infiltrate the tumor tissue, and interact with the target to finally trigger effector functions indispensable for tumor destruction. Chemokines are involved in circulation, homing, retention, and activation of immunocompetent cells. Although some of them are known to contribute to tumor growth and metastasis, others are responsible for changes in the tumor microenvironment that lead to extensive infiltration of lymphocytes, resulting in tumor eradication. Given their chemoattractive and activating properties, a role for chemokines in the development of the effector phase of the antitumor immune response has been suggested. Here, we emphasize the role of the chemokine-chemokine receptor network at multiple levels of the T-cell-mediated antitumor immune response. The identification of chemokine-dependent molecular mechanisms implicated in tumor-specific CTL trafficking, retention, and regulation of their in situ effector functions may offer new perspectives for development of innovative immunotherapeutic approaches to cancer treatment.

  8. Increases in Brain 1H-MR Glutamine and Glutamate Signals Following Acute Exhaustive Endurance Exercise in the Rat

    PubMed Central

    Świątkiewicz, Maciej; Fiedorowicz, Michał; Orzeł, Jarosław; Wełniak-Kamińska, Marlena; Bogorodzki, Piotr; Langfort, Józef; Grieb, Paweł

    2017-01-01

    Objective: Proton magnetic resonance spectroscopy (1H-MRS) in ultra-high magnetic field can be used for non-invasive quantitative assessment of brain glutamate (Glu) and glutamine (Gln) in vivo. Glu, the main excitatory neurotransmitter in the central nervous system, is efficiently recycled between synapses and presynaptic terminals through Glu-Gln cycle which involves glutamine synthase confined to astrocytes, and uses 60–80% of energy in the resting human and rat brain. During voluntary or involuntary exercise many brain areas are significantly activated, which certainly intensifies Glu-Gln cycle. However, studies on the effects of exercise on 1H-MRS Glu and/or Gln signals from the brain provided divergent results. The present study on rats was performed to determine changes in 1H-MRS signals from three brain regions engaged in motor activity consequential to forced acute exercise to exhaustion. Method: After habituation to treadmill running, rats were subjected to acute treadmill exercise continued to exhaustion. Each animal participating in the study was subject to two identical imaging sessions performed under light isoflurane anesthesia, prior to, and following the exercise bout. In control experiments, two imaging sessions separated by the period of rest instead of exercise were performed. 1H-NMR spectra were recorded from the cerebellum, striatum, and hippocampus using a 7T small animal MR scanner. Results: Following exhaustive exercise statistically significant increases in the Gln and Glx signals were found in all three locations, whereas increases in the Glu signal were found in the cerebellum and hippocampus. In control experiments, no changes in 1H-MRS signals were found. Conclusion: Increase in glutamine signals from the brain areas engaged in motor activity may reflect a disequilibrium caused by increased turnover in the glutamate-glutamine cycle and a delay in the return of glutamine from astrocytes to neurons. Increased turnover of Glu-Gln cycle

  9. Increases in Brain (1)H-MR Glutamine and Glutamate Signals Following Acute Exhaustive Endurance Exercise in the Rat.

    PubMed

    Świątkiewicz, Maciej; Fiedorowicz, Michał; Orzeł, Jarosław; Wełniak-Kamińska, Marlena; Bogorodzki, Piotr; Langfort, Józef; Grieb, Paweł

    2017-01-01

    Objective: Proton magnetic resonance spectroscopy ((1)H-MRS) in ultra-high magnetic field can be used for non-invasive quantitative assessment of brain glutamate (Glu) and glutamine (Gln) in vivo. Glu, the main excitatory neurotransmitter in the central nervous system, is efficiently recycled between synapses and presynaptic terminals through Glu-Gln cycle which involves glutamine synthase confined to astrocytes, and uses 60-80% of energy in the resting human and rat brain. During voluntary or involuntary exercise many brain areas are significantly activated, which certainly intensifies Glu-Gln cycle. However, studies on the effects of exercise on (1)H-MRS Glu and/or Gln signals from the brain provided divergent results. The present study on rats was performed to determine changes in (1)H-MRS signals from three brain regions engaged in motor activity consequential to forced acute exercise to exhaustion. Method: After habituation to treadmill running, rats were subjected to acute treadmill exercise continued to exhaustion. Each animal participating in the study was subject to two identical imaging sessions performed under light isoflurane anesthesia, prior to, and following the exercise bout. In control experiments, two imaging sessions separated by the period of rest instead of exercise were performed. (1)H-NMR spectra were recorded from the cerebellum, striatum, and hippocampus using a 7T small animal MR scanner. Results: Following exhaustive exercise statistically significant increases in the Gln and Glx signals were found in all three locations, whereas increases in the Glu signal were found in the cerebellum and hippocampus. In control experiments, no changes in (1)H-MRS signals were found. Conclusion: Increase in glutamine signals from the brain areas engaged in motor activity may reflect a disequilibrium caused by increased turnover in the glutamate-glutamine cycle and a delay in the return of glutamine from astrocytes to neurons. Increased turnover of Glu

  10. Comprehensive analysis of chemokines and cytokines secreted in the peritoneal cavity during laparotomy.

    PubMed

    Kawashima, Rei; Kawamura, Yuki I; Oshio, Tomoyuki; Mizutani, Noriko; Okada, Toshihiko; Kawamura, Yutaka J; Konishi, Fumio; Dohi, Taeko

    2012-01-01

    We recently found that chemokine-driven peritoneal cell aggregation is the primary mechanism of postoperative adhesion in a mouse model. To investigate this in humans, paired samples of peritoneal lavage fluid were obtained from seven patients immediately after incision (preoperative) and before closure (postoperative), and were assayed for the presence of 27 cytokines and chemokines using multiplex beads assay. As a result, IL-6 and CCL5 showed the most striking increase during operation. Recombinant CCL5 or lavage fluid induced chemotaxis of human peripheral blood mononuclear cells. We propose that CCL5 is possibly involved in the mechanism of postoperative adhesion in humans.

  11. Nitrite-mediated renal vasodilatation is increased during ischemic conditions via cGMP-independent signaling.

    PubMed

    Liu, Ming; Zollbrecht, Christa; Peleli, Maria; Lundberg, Jon O; Weitzberg, Eddie; Carlström, Mattias

    2015-07-01

    The kidney is vulnerable to hypoxia, and substantial efforts have been made to ameliorate renal ischemic injury secondary to pathological conditions. Stimulation of the nitrate-nitrite-nitric oxide pathway is associated with renal and cardiovascular protection in disease models, but less is known about the vascular effects during renal ischemia. This study was aimed at investigating the vascular effects of nitrite in the kidney during normoxic and ischemic conditions. Using a multiwire myograph system, we assessed nitrite-mediated relaxation (10(-9)-10(-4)mol/L) in isolated and preconstricted renal interlobar arteries from C57BL/6 mice under normal conditions (pO2 13kPa; pH 7.4) and with low oxygen tension and low pH to mimic ischemia (pO2 3kPa; pH 6.6). Xanthine oxidoreductase expression was analyzed by quantitative PCR, and production of reactive nitrogen species was measured by DAF-FM DA fluorescence. During normoxia significant vasodilatation (15±3%) was observed only at the highest concentration of nitrite, which was dependent on NO-sGC-cGMP signaling. The vasodilatory responses to nitrite were greatly sensitized and enhanced during hypoxia with low pH, demonstrating significant dilatation (11±1%) already in the physiological range (10(-8)mol/L), with a maximum response of 27±2% at 10(-4) mol/L. In contrast to normoxia, and to that observed with a classical NO donor (DEA NONOate), this sensitization was independent of sGC-cGMP signaling. Moreover, inhibition of various enzymatic systems reported to reduce nitrite in other vascular beds, i.e., aldehyde oxidase (raloxifene), aldehyde dehydrogenase (cyanamide), and NO synthase (L-NAME), had no effect on the nitrite response. However, inhibition of xanthine oxidoreductase (XOR; febuxostat or allopurinol) abolished the sensitized response to nitrite during hypoxia and acidosis. In conclusion, in contrast to normoxia, nitrite exerted potent vasorelaxation during ischemic conditions already at physiological

  12. Intensive removal of signal crayfish (Pacifastacus leniusculus) from rivers increases numbers and taxon richness of macroinvertebrate species

    PubMed Central

    Moorhouse, Tom P; Poole, Alison E; Evans, Laura C; Bradley, David C; Macdonald, David W

    2014-01-01

    Invasive species are a major cause of species extinction in freshwater ecosystems, and crayfish species are particularly pervasive. The invasive American signal crayfish Pacifastacus leniusculus has impacts over a range of trophic levels, but particularly on benthic aquatic macroinvertebrates. Our study examined the effect on the macroinvertebrate community of removal trapping of signal crayfish from UK rivers. Crayfish were intensively trapped and removed from two tributaries of the River Thames to test the hypothesis that lowering signal crayfish densities would result in increases in macroinvertebrate numbers and taxon richness. We removed 6181 crayfish over four sessions, resulting in crayfish densities that decreased toward the center of the removal sections. Conversely in control sections (where crayfish were trapped and returned), crayfish density increased toward the center of the section. Macroinvertebrate numbers and taxon richness were inversely correlated with crayfish densities. Multivariate analysis of the abundance of each taxon yielded similar results and indicated that crayfish removals had positive impacts on macroinvertebrate numbers and taxon richness but did not alter the composition of the wider macroinvertebrate community. Synthesis and applications: Our results demonstrate that non-eradication-oriented crayfish removal programmes may lead to increases in the total number of macroinvertebrates living in the benthos. This represents the first evidence that removing signal crayfish from riparian systems, at intensities feasible during control attempts or commercial crayfishing, may be beneficial for a range of sympatric aquatic macroinvertebrates. PMID:24634733

  13. Mechanisms and implications of air pollution particle associations with chemokines

    SciTech Connect

    Seagrave, JeanClare

    2008-11-01

    Inflammation induced by inhalation of air pollutant particles has been implicated as a mechanism for the adverse health effects associated with exposure to air pollution. The inflammatory response is associated with upregulation of various pro-inflammatory cytokines and chemokines. We have previously shown that diesel exhaust particles (DEP), a significant constituent of air pollution particulate matter in many urban areas, bind and concentrate IL-8, an important human neutrophil-attracting chemokine, and that the chemokine remains biologically active. In this report, we examine possible mechanisms of this association and the effects on clearance of the chemokine. The binding appears to be the result of ionic interactions between negatively charged particles and positively charged chemokine molecules, possibly combined with intercalation into small pores in the particles. The association is not limited to diesel exhaust particles and IL-8: several other particle types also adsorb the chemokine and several other cytokines are adsorbed onto the diesel particles. However, there are wide ranges in the effectiveness of various particle types and various cytokines. Finally, male Fisher 344 rats were intratracheally instilled with chemokine alone or combined with diesel exhaust or silica particles under isofluorane anesthesia. In contrast to silica particles, which do not bind the chemokine, the presence of diesel exhaust particles, which bind the chemokine, prolonged the retention of the chemokine.

  14. Structural Analysis of Chemokine Receptor-Ligand Interactions.

    PubMed

    Arimont, Marta; Sun, Shan-Liang; Leurs, Rob; Smit, Martine; de Esch, Iwan J P; de Graaf, Chris

    2017-03-10

    This review focuses on the construction and application of structural chemokine receptor models for the elucidation of molecular determinants of chemokine receptor modulation and the structure-based discovery and design of chemokine receptor ligands. A comparative analysis of ligand binding pockets in chemokine receptors is presented, including a detailed description of the CXCR4, CCR2, CCR5, CCR9, and US28 X-ray structures, and their implication for modeling molecular interactions of chemokine receptors with small-molecule ligands, peptide ligands, and large antibodies and chemokines. These studies demonstrate how the integration of new structural information on chemokine receptors with extensive structure-activity relationship and site-directed mutagenesis data facilitates the prediction of the structure of chemokine receptor-ligand complexes that have not been crystallized. Finally, a review of structure-based ligand discovery and design studies based on chemokine receptor crystal structures and homology models illustrates the possibilities and challenges to find novel ligands for chemokine receptors.

  15. Anxiolytic-Like Effects of Increased Ghrelin Receptor Signaling in the Amygdala

    PubMed Central

    Jensen, Morten; Ratner, Cecilia; Rudenko, Olga; Christiansen, Søren H.; Skov, Louise J.; Hundahl, Cecilie; Woldbye, David P.D.

    2016-01-01

    Background: Besides the well-known effects of ghrelin on adiposity and food intake regulation, the ghrelin system has been shown to regulate aspects of behavior including anxiety and stress. However, the effect of virus-mediated overexpression of the ghrelin receptor in the amygdala has not previously been addressed directly. Methods: First, we examined the acute effect of peripheral ghrelin administration on anxiety- and depression-like behavior using the open field, elevated plus maze, forced swim, and tail suspension tests. Next, we examined the effect of peripheral ghrelin administration and ghrelin receptor deficiency on stress in a familiar and social environment using the Intellicage system. Importantly, we also used a novel approach to study ghrelin receptor signaling in the brain by overexpressing the ghrelin receptor in the amygdala. We examined the effect of ghrelin receptor overexpression on anxiety-related behavior before and after acute stress and measured the modulation of serotonin receptor expression. Results: We found that ghrelin caused an anxiolytic-like effect in both the open field and elevated plus maze tests. Additionally, it attenuated air-puff–induced stress in the social environment, while the opposite was shown in ghrelin receptor deficient mice. Finally, we found that overexpression of the ghrelin receptor in the basolateral division of the amygdala caused an anxiolytic-like effect and decreased the 5HT1a receptor expression. Conclusions: Ghrelin administration and overexpression of the ghrelin receptor in the amygdala induces anxiolytic-like behavior. Since the ghrelin receptor has high constitutive activity, ligand-independent signaling in vivo may be important for the observed anxiolytic-like effects. The anxiolytic effects seem to be mediated independently from the HPA axis, potentially engaging the central serotonin system. PMID:26578081

  16. Profiling Heparin-Chemokine Interactions Using Synthetic Tools

    PubMed Central

    de Paz, Jose L.; Moseman, E. Ashley; Noti, Christian; Polito, Laura; von Andrian, Ulrich H.; Seeberger, Peter H.

    2009-01-01

    Glycosaminoglycans (GAGs), such as heparin or heparan sulfate, are required for the in vivo function of chemokines. Chemokines play a crucial role in the recruitment of leukocyte subsets to sites of inflammation and lymphocytes trafficking. GAG-chemokine interactions mediate cell migration and determine which leukocyte subsets enter tissues. Identifying the exact GAC sequences that bind to particular chemokines is key to understand chemokine function at the molecular level and develop strategies to interfere with chemokine-mediated processes. Here, we characterize the heparin binding profiles of eight chemokines (CCL21, IL-8, CXCL12, CXCL13, CCL19, CCL25, CCL28, and CXCL16) by employing heparin microarrays containing a small library of synthetic heparin oligosaccharides. The chemokines differ significantly in their interactions with heparin oligosaccharides: While some chemokines, (e.g., CCL21) strongly bind to a hexasaccharide containing the GlcNSO3(6-OSO3)-IdoA(2-OSO3) repeating unit, CCL19 does not bind and CXCL12 binds only weakly. The carbohydrate microarray binding results were validated by surface plasmon resonance experiments. In vitro chemotaxis assays revealed that dendrimers coated with the fully sulfated heparin hexasaccharide inhibit lymphocyte migration toward CCL21. Migration toward CXCL12 or CCL19 was not affected. These in vitro homing assays indicate that multivalent synthetic heparin dendrimers inhibit the migration of lymphocytes toward certain chemokine gradients by blocking the formation of a chemokine concentration gradient on GAG endothelial chains. These findings are in agreement with preliminary in vivo measurements of circulating lymphocytes. The results presented here contribute to the understanding of GAG-chemokine interactions, a first step toward the design of novel drugs that modulate chemokine activity. PMID:18030990

  17. Increased basal level of Akt-dependent insulin signaling may be responsible for the development of insulin resistance

    PubMed Central

    Liu, Hui-Yu; Hong, Tao; Wen, Ge-Bo; Han, Jianmin; Zuo, Degen; Liu, Zhenqi

    2009-01-01

    A majority of subjects with insulin resistance and hyperinsulinemia can maintain their blood glucose levels normal for the whole life presumably through protein kinase B (Akt)-dependent insulin signaling. In this study, we found that the basal Akt phosphorylation level was increased in liver and gastrocnemius of mice under the high-fat diet (HFD). Levels of mitochondrial DNA and expression of some mitochondrion-associated genes were decreased by the HFD primarily in liver. Triglyceride content was increased in both liver and gastrocnemius by the HFD. Oxidative stress was induced by the HFD in both liver and gastrocnemius. Insulin sensitivity was decreased by the HFD. All of these changes were largely or completely reversed by treatment of animals with the phosphatidylinositol 3-kinase inhibitor LY-294002 during the time when animals usually do not eat. Consequently, the overall insulin sensitivity was increased by treatment with LY-294002. Together, our results indicate that increased basal Akt-dependent insulin signaling suppresses mitochondrial production, increases ectopic fat accumulation, induces oxidative stress, and desensitizes insulin signaling in subjects with insulin resistance and hyperinsulinemia. PMID:19638508

  18. Disturbed MEK/ERK signaling increases osteoclast activity via the Hedgehog-Gli pathway in postmenopausal osteoporosis.

    PubMed

    Li, Xiaojie; Jie, Qiang; Zhang, Hongyang; Zhao, Yantao; Lin, Yangjing; Du, Junjie; Shi, Jun; Wang, Long; Guo, Kai; Li, Yong; Wang, Chunhui; Gao, Bo; Huang, Qiang; Liu, Jian; Yang, Liu; Luo, Zhuojing

    2016-11-01

    Postmenopausal osteoporosis is a worldwide health problem and is characterized by increased and activated osteoclasts. However, the mechanism by which osteoclasts are dysregulated in postmenopausal osteoporosis is not fully understood. In this study, we found that the Hedgehog-Gli pathway was upregulated in postmenopausal osteoporotic osteoclasts and that 17β-estradiol both inhibited osteoclastogenesis and induced osteoclast apoptosis by downregulating Hedgehog-Gli signaling. Furthermore, we demonstrated that the Hedgehog-Gli pathway was negatively regulated by MEK/ERK signaling and that this effect was Sonic Hedgehog (SHH)-dependent and was partially blocked by an anti-SHH antibody. Moreover, we found that the stimulatory effect of Hedgehog signaling on osteoclastogenesis and the inhibitory effect on osteoclast apoptosis were dependent on the Gli family of transcription factors. The pathways and molecules that contribute to the regulation of osteoclastogenesis and apoptosis represent potential new strategies for designing molecular drugs for the treatment of postmenopausal osteoporosis.

  19. Quantitative comparison of C-X-C chemokines produced by endotoxin-stimulated human alveolar macrophages.

    PubMed

    Goodman, R B; Strieter, R M; Frevert, C W; Cummings, C J; Tekamp-Olson, P; Kunkel, S L; Walz, A; Martin, T R

    1998-07-01

    The C-X-C chemokines are a structurally related and functionally redundant family of proteins with neutrophil chemotactic activity. Many of the C-X-C chemokines are produced by endotoxin-stimulated alveolar macrophages (AMs), but knowledge of their relative quantities and their relative contributions to the total chemotactic activity released from these cells is incomplete. Human AMs were stimulated with or without Escherichia coli endotoxin for 2, 4, 8, and 24 h. The mRNA sequences of interleukin (IL)-8, the 78-amino acid epithelial cell-derived neutrophil activator (ENA-78), growth-related protein (GRO) alpha, GRObeta, and GROgamma were cloned by PCR and identified by sequence analysis. The relative mRNA quantities were compared by Northern analysis, and IL-8 was found to predominate. Similarly, IL-8 protein concentrations in the cell supernatants were consistently higher than either the ENA-78 or GRO concentration, and by 24 h, IL-8 concentrations were 10-fold higher than those of the other C-X-C chemokines. Blocking polyclonal antibodies to IL-8 substantially reduced the chemotactic activity in the AM supernatants, whereas antibodies to ENA-78 and GRO had little or no effect. We conclude that IL-8 is the predominant C-X-C chemokine and the dominant neutrophil chemoattractant accumulating in 24-h supernatants of lipopolysaccharide-stimulated human AMs. These studies provide insight into potentially effective strategies of interrupting AM-derived inflammatory signals in the lungs.

  20. mu-Opioid receptor stimulation in the nucleus accumbens elevates fatty tastant intake by increasing palatability and suppressing satiety signals.

    PubMed

    Katsuura, Yoshihiro; Heckmann, Jennifer A; Taha, Sharif A

    2011-07-01

    Infusion of a μ-opioid receptor (MOR) agonist into the nucleus accumbens (NAcc) drives voracious food intake, an effect hypothesized to occur through increased tastant palatability. While intake of many palatable foods is elevated by MOR stimulation, this manipulation has a preferential effect on fatty food ingestion. Consumption of high-fat foods is increased by NAcc MOR stimulation even in rats that prefer a carbohydrate-rich alternative under baseline conditions. This suggests that NAcc MOR stimulation may not simply potentiate palatability signals and raises the possibility that mechanisms mediating fat intake may be distinct from those underlying intake of other tastants. The present study was conducted to investigate the physiological mechanisms underlying the effects of NAcc MOR stimulation on fatty food intake. In experiment 1, we analyzed lick microstructure in rats ingesting Intralipid to identify the changes underlying feeding induced by infusion of a MOR-specific agonist into the NAcc. MOR stimulation in the NAcc core, but not shell, increased burst duration and first-minute licks, while simultaneously increasing the rate and duration of Intralipid ingestion. These results suggest that MOR activation in the core increases Intralipid palatability and attenuates inhibitory postingestive feedback. In experiment 2, we measured the effects of MOR stimulation in the NAcc core on consumption of nonnutritive olestra. A MOR-specific agonist dose dependently increased olestra intake, demonstrating that caloric signaling is not required for hyperphagia induced by NAcc MOR stimulation. Feeding induced by drug infusion in both experiments 1 and 2 was blocked by a MOR antagonist. In experiment 3, we determined whether MOR activation in the NAcc core could attenuate satiety-related signaling caused by infusion of the melanocortin agonist MTII into the third ventricle. Suppression of intake caused by MTII was reversed by MOR stimulation. Together, our results suggest

  1. Metabotropic glutamate receptor 6 signaling enhances TRPM1 calcium channel function and increases melanin content in human melanocytes.

    PubMed

    Devi, Sulochana; Markandeya, Yogananda; Maddodi, Nityanand; Dhingra, Anuradha; Vardi, Noga; Balijepalli, Ravi C; Setaluri, Vijayasaradhi

    2013-05-01

    Mutations in TRPM1, a calcium channel expressed in retinal bipolar cells and epidermal melanocytes, cause complete congenital stationary night blindness with no discernible skin phenotype. In the retina, TRPM1 activity is negatively coupled to metabotropic glutamate receptor 6 (mGluR6) signaling through Gαo and TRPM1 mutations result in the loss of responsiveness of TRPM1 to mGluR6 signaling. Here, we show that human melanocytes express mGluR6, and treatment of melanocytes with L-AP4, a type III mGluR-selective agonist, enhances Ca(2+) uptake. Knockdown of TRPM1 or mGluR6 by shRNA abolished L-AP4-induced Ca(2+) influx and TRPM1 currents, showing that TRPM1 activity in melanocytes is positively coupled to mGluR6 signaling. Gαo protein is absent in melanocytes. However, forced expression of Gαo restored negative coupling of TRPM1 to mGluR6 signaling, but treatment with pertussis toxin, an inhibitor of Gi /Go proteins, did not affect basal or mGluR6-induced Ca(2+) uptake. Additionally, chronic stimulation of mGluR6 altered melanocyte morphology and increased melanin content. These data suggest differences in coupling of TRPM1 function to mGluR6 signaling explain different cellular responses to glutamate in the retina and the skin.

  2. Metabotropic glutamate receptor 6 signaling enhances TRPM1 calcium channel function and increases melanin content in human melanocytes

    PubMed Central

    Devi, Sulochana; Markandeya, Yogananda; Maddodi, Nityanand; Dhingra, Anuradha; Vardi, Noga; Balijepalli, Ravi C; Setaluri, Vijayasaradhi

    2013-01-01

    SUMMARY Mutations in TRPM1, a calcium channel expressed in retinal bipolar cells and epidermal melanocytes, cause complete congenital stationary night blindness with no discernible skin phenotype. In the retina, TRPM1 activity is negatively coupled to metabotropic glutamate receptor 6 (mGluR6) signaling through Gαo and TRPM1 mutations result in the loss of responsiveness of TRPM1 to mGluR6 signaling. Here, we show that human melanocytes express mGluR6 and treatment of melanocytes with L-AP4, a type III mGluR-selective agonist, enhances Ca2+ uptake. Knockdown of TRPM1 or mGluR6 by shRNA abolished L-AP4-induced Ca2+ influx and TRPM1 currents showing that TRPM1 activity in melanocytes is positively coupled to mGluR6 signaling. Gαo protein is absent in melanocytes. However, forced expression of Gαo restored negative coupling of TRPM1 to mGluR6 signaling, but treatment with and pertussis toxin, an inhibitor of Gi/Go proteins, did not affect basal or mGluR6-induced Ca2+ uptake. Additionally, chronic stimulation of mGluR6 altered melanocyte morphology and increased melanin content. These data suggest differences in coupling of TRPM1 function to mGluR6 signaling explain different cellular responses to glutamate in the retina and the skin. PMID:23452348

  3. Nicotine decreases ethanol-induced dopamine signaling and increases self-administration via stress hormones.

    PubMed

    Doyon, William M; Dong, Yu; Ostroumov, Alexey; Thomas, Alyse M; Zhang, Tao A; Dani, John A

    2013-08-07

    Tobacco smoking is a well-known risk factor for subsequent alcohol abuse, but the neural events underlying this risk remain largely unknown. Alcohol and nicotine reinforcement involve common neural circuitry, including the mesolimbic dopamine system. We demonstrate in rodents that pre-exposure to nicotine increases alcohol self-administration and decreases alcohol-induced dopamine responses. The blunted dopamine response was due to increased inhibitory synaptic transmission onto dopamine neurons. Blocking stress hormone receptors prior to nicotine exposure prevented all interactions with alcohol that we measured, including the increased inhibition onto dopamine neurons, the decreased dopamine responses, and the increased alcohol self-administration. These results indicate that nicotine recruits neuroendocrine systems to influence neurotransmission and behavior associated with alcohol reinforcement.

  4. COPD promotes migration of A549 lung cancer cells: the role of chemokine CCL21.

    PubMed

    Kuźnar-Kamińska, Barbara; Mikuła-Pietrasik, Justyna; Sosińska, Patrycja; Książek, Krzysztof; Batura-Gabryel, Halina

    2016-01-01

    Patients with COPD develop lung cancer more frequently than healthy smokers. At the same time, molecular mediators promoting various aspects of cancer cell progression are still elusive. In this report, we examined whether COPD can be coupled with increased migration of non-small-cell lung cancer cells A549 and, if so, whether this effect may be related to altered production and activity of chemokines CCL21, CXCL5, and CXCL12. The study showed that the migration of A549 cells through the polycarbonate membrane and basement membrane extract toward a chemotactic gradient elicited by serum from patients with COPD was markedly higher as compared with serum from healthy donors. The concentration of CCL21 and CXCL12, but not CXCL5, in serum from patients with COPD was also increased. Experiments in which CCL21- and CXCL12-dependent signaling was blocked revealed that increased migration of the cancer cells upon treatment with serum from patients with COPD was mediated exclusively by CCL21. Collectively, our results indicate that COPD may contribute to the progression of lung cancer via CCL21-dependent intensification of cancer cell migration.

  5. To quiver or to shiver: increased melanization benefits thermoregulation, but reduces warning signal efficacy in the wood tiger moth

    PubMed Central

    Hegna, Robert H.; Nokelainen, Ossi; Hegna, Jonathan R.; Mappes, Johanna

    2013-01-01

    Melanin production is often considered costly, yet beneficial for thermoregulation. Studies of variation in melanization and the opposing selective forces that underlie its variability contribute greatly to understanding natural selection. We investigated whether melanization benefits are traded off with predation risk to promote observed local and geographical variation in the warning signal of adult male wood tiger moths (Parasemia plantaginis). Warning signal variation is predicted to reduce survival in aposematic species. However, in P. plantaginis, male hindwings are either yellow or white in Europe, and show continuous variation in melanized markings that cover 20 to 90 per cent of the hindwing. We found that the amount of melanization increased from 40 to 59 per cent between Estonia (58° N) and north Finland (67° N), suggesting melanization carries thermoregulatory benefits. Our thermal measurements showed that more melanic individuals warmed up more quickly on average than less melanic individuals, which probably benefits flight in cold temperatures. With extensive field experiments in central Finland and the Alpine region, we found that more melanic individuals suffered increased predation. Together, our data suggest that warning signal efficiency is constrained by thermoregulatory benefits. Differences in relative costs and benefits of melanin probably help to maintain the geographical warning signal differences. PMID:23363631

  6. Astrocytes increase ATP exocytosis mediated calcium signaling in response to microgroove structures.

    PubMed

    Singh, Ajay V; Raymond, Michael; Pace, Fabiano; Certo, Anthony; Zuidema, Jonathan M; McKay, Christopher A; Gilbert, Ryan J; Lu, X Lucas; Wan, Leo Q

    2015-01-19

    Following central nervous system (CNS) injury, activated astrocytes form glial scars, which inhibit axonal regeneration, leading to long-term functional deficits. Engineered nanoscale scaffolds guide cell growth and enhance regeneration within models of spinal cord injury. However, the effects of micro-/nanosize scaffolds on astrocyte function are not well characterized. In this study, a high throughput (HTP) microscale platform was developed to study astrocyte cell behavior on micropatterned surfaces containing 1 μm spacing grooves with a depth of 250 or 500 nm. Significant changes in cell and nuclear elongation and alignment on patterned surfaces were observed, compared to on flat surfaces. The cytoskeleton components (particularly actin filaments and focal adhesions) and nucleus-centrosome axis were aligned along the grooved direction as well. More interestingly, astrocytes on micropatterned surfaces showed enhanced mitochondrial activity with lysosomes localized at the lamellipodia of the cells, accompanied by enhanced adenosine triphosphate (ATP) release and calcium activities. These data indicate that the lysosome-mediated ATP exocytosis and calcium signaling may play an important role in astrocytic responses to substrate topology. These new findings have furthered our understanding of the biomechanical regulation of astrocyte cell-substrate interactions, and may benefit the optimization of scaffold design for CNS healing.

  7. BCR and Endosomal TLR Signals Synergize to Increase AID Expression and Establish Central B Cell Tolerance.

    PubMed

    Kuraoka, Masayuki; Snowden, Pilar B; Nojima, Takuya; Verkoczy, Laurent; Haynes, Barton F; Kitamura, Daisuke; Kelsoe, Garnett

    2017-02-14

    Activation-induced cytidine deaminase (AID) is required to purge autoreactive immature and transitional-1 (immature/T1) B cells at the first tolerance checkpoint, but how AID selectively removes self-reactive B cells is unclear. We now show that B cell antigen receptor (BCR) and endosomal Toll-like receptor (TLR) signals synergize to elicit high levels of AID expression in immature/T1 B cells. This synergy is restricted to ligands for endocytic TLR and requires phospholipase-D activation, endosomal acidification, and MyD88. The first checkpoint is significantly impaired in AID- or MyD88-deficient mice and in mice doubly heterozygous for AID and MyD88, suggesting interaction of these factors in central B cell tolerance. Moreover, administration of chloroquine, an inhibitor of endosomal acidification, results in a failure to remove autoreactive immature/T1 B cells in mice. We propose that a BCR/TLR pathway coordinately establishes central tolerance by hyper-activating AID in immature/T1 B cells that bind ligands for endosomal TLRs.

  8. Multiple Drug Treatments That Increase cAMP Signaling Restore Long-Term Memory and Aberrant Signaling in Fragile X Syndrome Models

    PubMed Central

    Choi, Catherine H.; Schoenfeld, Brian P.; Bell, Aaron J.; Hinchey, Joseph; Rosenfelt, Cory; Gertner, Michael J.; Campbell, Sean R.; Emerson, Danielle; Hinchey, Paul; Kollaros, Maria; Ferrick, Neal J.; Chambers, Daniel B.; Langer, Steven; Sust, Steven; Malik, Aatika; Terlizzi, Allison M.; Liebelt, David A.; Ferreiro, David; Sharma, Ali; Koenigsberg, Eric; Choi, Richard J.; Louneva, Natalia; Arnold, Steven E.; Featherstone, Robert E.; Siegel, Steven J.; Zukin, R. Suzanne; McDonald, Thomas V.; Bolduc, Francois V.; Jongens, Thomas A.; McBride, Sean M. J.

    2016-01-01

    Fragile X is the most common monogenic disorder associated with intellectual disability (ID) and autism spectrum disorders (ASD). Additionally, many patients are afflicted with executive dysfunction, ADHD, seizure disorder and sleep disturbances. Fragile X is caused by loss of FMRP expression, which is encoded by the FMR1 gene. Both the fly and mouse models of fragile X are also based on having no functional protein expression of their respective FMR1 homologs. The fly model displays well defined cognitive impairments and structural brain defects and the mouse model, although having subtle behavioral defects, has robust electrophysiological phenotypes and provides a tool to do extensive biochemical analysis of select brain regions. Decreased cAMP signaling has been observed in samples from the fly and mouse models of fragile X as well as in samples derived from human patients. Indeed, we have previously demonstrated that strategies that increase cAMP signaling can rescue short term memory in the fly model and restore DHPG induced mGluR mediated long term depression (LTD) in the hippocampus to proper levels in the mouse model (McBride et al., 2005; Choi et al., 2011, 2015). Here, we demonstrate that the same three strategies used previously with the potential to be used clinically, lithium treatment, PDE-4 inhibitor treatment or mGluR antagonist treatment can rescue long term memory in the fly model and alter the cAMP signaling pathway in the hippocampus of the mouse model. PMID:27445731

  9. MTMR3 risk allele enhances innate receptor-induced signaling and cytokines by decreasing autophagy and increasing caspase-1 activation.

    PubMed

    Lahiri, Amit; Hedl, Matija; Abraham, Clara

    2015-08-18

    Inflammatory bowel disease (IBD) is characterized by dysregulated host:microbial interactions and cytokine production. Host pattern recognition receptors (PRRs) are critical in regulating these interactions. Multiple genetic loci are associated with IBD, but altered functions for most, including in the rs713875 MTMR3/HORMAD2/LIF/OSM region, are unknown. We identified a previously undefined role for myotubularin-related protein 3 (MTMR3) in amplifying PRR-induced cytokine secretion in human macrophages and defined MTMR3-initiated mechanisms contributing to this amplification. MTMR3 decreased PRR-induced phosphatidylinositol 3-phosphate (PtdIns3P) and autophagy levels, thereby increasing PRR-induced caspase-1 activation, autocrine IL-1β secretion, NFκB signaling, and, ultimately, overall cytokine secretion. This MTMR3-mediated regulation required the N-terminal pleckstrin homology-GRAM domain and Cys413 within the phosphatase domain of MTMR3. In MTMR3-deficient macrophages, reducing the enhanced autophagy or restoring NFκB signaling rescued PRR-induced cytokines. Macrophages from rs713875 CC IBD risk carriers demonstrated increased MTMR3 expression and, in turn, decreased PRR-induced PtdIns3P and autophagy and increased PRR-induced caspase-1 activation, signaling, and cytokine secretion. Thus, the rs713875 IBD risk polymorphism increases MTMR3 expression, which modulates PRR-induced outcomes, ultimately leading to enhanced PRR-induced cytokines.

  10. Plasmatic proinflammatory chemokines levels are tricky markers to monitoring HTLV-1 carriers.

    PubMed

    Chaves, Daniel Gonçalves; Sales, Camila Campos; de Cássia Gonçalves, Poliane; da Silva-Malta, Maria Clara Fernandes; Romanelli, Luiz Cláudio; Ribas, João Gabriel; de Freitas Carneiro-Proietti, Anna Bárbara; Martins, Marina Lobato

    2016-08-01

    The human T-cell leukemia virus type 1 (HTLV-1) is present throughout the world and is associated with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and other inflammatory conditions. The pathogenesis of HAM/TSP involves a chronic inflammatory response in central nervous system (CNS), with the presence of HTLV-1 infected cells and HTLV-1-specific CD8+ lymphocytes. Chemokines may have a role in the infiltration of these cells into the CNS. In this context, the present study analyzed the level of plasmatic chemokines CCL2 (MCP-1), CCL5 (RANTES), IL8 (CXCL8), CXCL9 (MIG), and CXCL10 (IP-10) and HTLV-1 proviral load from peripheral blood in 162 asymptomatic carriers and 136 HAM/TSP patients to determine the differences that be associated with the clinical status of the HTLV-1 infection. The results showed that patients with HAM/TSP have significantly higher levels of IL8 and CXCL9, and that the level of IL8, CXCL9 and CXCL10 was significantly greater in HTLV-1 infected individuals with high (>1%) than those with low proviral load (<1%). However, the levels of the chemokines tested have not showed high sensitivity to discriminate HAM/TSP patients from asymptomatic carriers. In addition, chemokine profiles in asymptomatic carriers and HAM/TSP groups were similar, with no significant increased frequency of higher producers of chemokines in HAM/TSP individuals. Results indicate that the heterogeneity of the individuals in the groups regarding time of infection, duration of disease, proviral load level and other possible confound factors may impair the use of chemokines levels to monitor HTLV-1 carriers in clinical practice. J. Med. Virol. 88:1438-1447, 2016. © 2016 Wiley Periodicals, Inc.

  11. Strong signal increase in STED fluorescence microscopy by imaging regions of subdiffraction extent

    PubMed Central

    Göttfert, Fabian; Pleiner, Tino; Heine, Jörn; Westphal, Volker; Görlich, Dirk; Sahl, Steffen J.; Hell, Stefan W.

    2017-01-01

    Photobleaching remains a limiting factor in superresolution fluorescence microscopy. This is particularly true for stimulated emission depletion (STED) and reversible saturable/switchable optical fluorescence transitions (RESOLFT) microscopy, where adjacent fluorescent molecules are distinguished by sequentially turning them off (or on) using a pattern of light formed as a doughnut or a standing wave. In sample regions where the pattern intensity reaches or exceeds a certain threshold, the molecules are essentially off (or on), whereas in areas where the intensity is lower, that is, around the intensity minima, the molecules remain in the initial state. Unfortunately, the creation of on/off state differences on subdiffraction scales requires the maxima of the intensity pattern to exceed the threshold intensity by a large factor that scales with the resolution. Hence, when recording an image by scanning the pattern across the sample, each molecule in the sample is repeatedly exposed to the maxima, which exacerbates bleaching. Here, we introduce MINFIELD, a strategy for fundamentally reducing bleaching in STED/RESOLFT nanoscopy through restricting the scanning to subdiffraction-sized regions. By safeguarding the molecules from the intensity of the maxima and exposing them only to the lower intensities (around the minima) needed for the off-switching (on-switching), MINFIELD largely avoids detrimental transitions to higher molecular states. A bleaching reduction by up to 100-fold is demonstrated. Recording nanobody-labeled nuclear pore complexes in Xenopus laevis cells showed that MINFIELD-STED microscopy resolved details separated by <25 nm where conventional scanning failed to acquire sufficient signal. PMID:28193881

  12. Strong signal increase in STED fluorescence microscopy by imaging regions of subdiffraction extent.

    PubMed

    Göttfert, Fabian; Pleiner, Tino; Heine, Jörn; Westphal, Volker; Görlich, Dirk; Sahl, Steffen J; Hell, Stefan W

    2017-02-28

    Photobleaching remains a limiting factor in superresolution fluorescence microscopy. This is particularly true for stimulated emission depletion (STED) and reversible saturable/switchable optical fluorescence transitions (RESOLFT) microscopy, where adjacent fluorescent molecules are distinguished by sequentially turning them off (or on) using a pattern of light formed as a doughnut or a standing wave. In sample regions where the pattern intensity reaches or exceeds a certain threshold, the molecules are essentially off (or on), whereas in areas where the intensity is lower, that is, around the intensity minima, the molecules remain in the initial state. Unfortunately, the creation of on/off state differences on subdiffraction scales requires the maxima of the intensity pattern to exceed the threshold intensity by a large factor that scales with the resolution. Hence, when recording an image by scanning the pattern across the sample, each molecule in the sample is repeatedly exposed to the maxima, which exacerbates bleaching. Here, we introduce MINFIELD, a strategy for fundamentally reducing bleaching in STED/RESOLFT nanoscopy through restricting the scanning to subdiffraction-sized regions. By safeguarding the molecules from the intensity of the maxima and exposing them only to the lower intensities (around the minima) needed for the off-switching (on-switching), MINFIELD largely avoids detrimental transitions to higher molecular states. A bleaching reduction by up to 100-fold is demonstrated. Recording nanobody-labeled nuclear pore complexes in Xenopus laevis cells showed that MINFIELD-STED microscopy resolved details separated by <25 nm where conventional scanning failed to acquire sufficient signal.

  13. Nitric oxide increases GLUT4 expression and regulates AMPK signaling in skeletal muscle.

    PubMed

    Lira, Vitor A; Soltow, Quinlyn A; Long, Jodi H D; Betters, Jenna L; Sellman, Jeff E; Criswell, David S

    2007-10-01

    Nitric oxide (NO) and 5'-AMP-activated protein kinase (AMPK) are involved in glucose transport and mitochondrial biogenesis in skeletal muscle. Here, we examined whether NO regulates the expression of the major glucose transporter in muscle (GLUT4) and whether it influences AMPK-induced upregulation of GLUT4. At low levels, the NO donor S-nitroso-N-penicillamine (SNAP, 1 and 10 microM) significantly increased GLUT4 mRNA ( approximately 3-fold; P < 0.05) in L6 myotubes, and cotreatment with the AMPK inhibitor compound C ablated this effect. The cGMP analog 8-bromo-cGMP (8-Br-cGMP, 2 mM) increased GLUT4 mRNA by approximately 50% (P < 0.05). GLUT4 protein expression was elevated 40% by 2 days treatment with 8-Br-cGMP, whereas 6 days treatment with 10 microM SNAP increased GLUT4 expression by 65%. Cotreatment of cultures with the guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one prevented the SNAP-induced increase in GLUT4 protein. SNAP (10 microM) also induced significant phosphorylation of alpha-AMPK and acetyl-CoA carboxylase and translocation of phosphorylated alpha-AMPK to the nucleus. Furthermore, L6 myotubes exposed to 5-aminoimidazole-4-carboxamide-1-beta-d-ribofuranoside (AICAR) for 16 h presented an approximately ninefold increase in GLUT4 mRNA, whereas cotreatment with the non-isoform-specific NOS inhibitor N(G)-nitro-l-arginine methyl ester, prevented approximately 70% of this effect. In vivo, GLUT4 mRNA was increased 1.8-fold in the rat plantaris muscle 12 h after AICAR injection, and this induction was reduced by approximately 50% in animals cotreated with the neuronal and inducible nitric oxide synthases selective inhibitor 1-(2-trifluoromethyl-phenyl)-imidazole. We conclude that, in skeletal muscle, NO increases GLUT4 expression via a cGMP- and AMPK-dependent mechanism. The data are consistent with a role for NO in the regulation of AMPK, possibly via control of cellular activity of AMPK kinases and/or AMPK phosphatases.

  14. Extended field-of-view and increased-signal 3D holographic illumination with time-division multiplexing.

    PubMed

    Yang, Samuel J; Allen, William E; Kauvar, Isaac; Andalman, Aaron S; Young, Noah P; Kim, Christina K; Marshel, James H; Wetzstein, Gordon; Deisseroth, Karl

    2015-12-14

    Phase spatial light modulators (SLMs) are widely used for generating multifocal three-dimensional (3D) illumination patterns, but these are limited to a field of view constrained by the pixel count or size of the SLM. Further, with two-photon SLM-based excitation, increasing the number of focal spots penalizes the total signal linearly--requiring more laser power than is available or can be tolerated by the sample. Here we analyze and demonstrate a method of using galvanometer mirrors to time-sequentially reposition multiple 3D holograms, both extending the field of view and increasing the total time-averaged two-photon signal. We apply our approach to 3D two-photon in vivo neuronal calcium imaging.

  15. Extended field-of-view and increased-signal 3D holographic illumination with time-division multiplexing

    PubMed Central

    Yang, Samuel J.; Allen, William E.; Kauvar, Isaac; Andalman, Aaron S.; Young, Noah P.; Kim, Christina K.; Marshel, James H.; Wetzstein, Gordon; Deisseroth, Karl

    2016-01-01

    Phase spatial light modulators (SLMs) are widely used for generating multifocal three-dimensional (3D) illumination patterns, but these are limited to a field of view constrained by the pixel count or size of the SLM. Further, with two-photon SLM-based excitation, increasing the number of focal spots penalizes the total signal linearly—requiring more laser power than is available or can be tolerated by the sample. Here we analyze and demonstrate a method of using galvanometer mirrors to time-sequentially reposition multiple 3D holograms, both extending the field of view and increasing the total time-averaged two-photon signal. We apply our approach to 3D two-photon in vivo neuronal calcium imaging. PMID:26699047

  16. Human cytomegalovirus encoded chemokine receptor US28 activates the HIF-1α/PKM2 axis in glioblastoma cells

    PubMed Central

    van Senten, Jeffrey R.; Fraile-Ramos, Alberto; Siderius, Marco; Smit, Martine J.

    2016-01-01

    The human cytomegalovirus (HCMV) encoded chemokine receptor US28 promotes tumorigenesis through activation of various proliferative and angiogenic signaling pathways. Upon infection, US28 displays constitutive activity and signals in a G protein-dependent manner, hijacking the host's cellular machinery. In tumor cells, the hypoxia inducible factor-1α/pyruvate kinase M2 (HIF-1α/PKM2) axis plays an important role by supporting proliferation, angiogenesis and reprogramming of energy metabolism. In this study we show that US28 signaling results in activation of the HIF-1α/PKM2 feedforward loop in fibroblasts and glioblastoma cells. The constitutive activity of US28 increases HIF-1 protein stability through a Gαq-, CaMKII- and Akt/mTOR-dependent mechanism. Furthermore, we found that VEGF and lactate secretion are increased and HIF-1 target genes, glucose transporter type 1 (GLUT1) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), involved in glucose metabolism, are upregulated in US28 expressing cells. In addition, PKM2 is phosphorylated and found to be in a tumor-associated dimeric state upon US28 expression. Also in HCMV-infected cells HIF-1 activity is enhanced, which in part is US28-dependent. Finally, increased proliferation of cells expressing US28 is abolished upon inhibition of the HIF-1α/PKM2 cascade. These data highlight the importance of HIF-1α and PKM2 in US28-induced proliferation, angiogenesis and metabolic reprogramming. PMID:27602585

  17. MDMA Increases Excitability in the Dentate Gyrus: Role of 5HT2A Receptor Induced PGE2 Signaling

    PubMed Central

    Collins, Stuart A.; Huff, Courtney; Chiaia, Nicolas; Gudelsky, Gary A.; Yamamoto, Bryan K.

    2015-01-01

    MDMA is a widely abused psychostimulant which causes release of serotonin in various forebrain regions. Recently, we reported that MDMA increases extracellular glutamate concentrations in the dentate gyrus, via activation of 5HT2A receptors. We examined the role of prostaglandin signaling in mediating the effects of 5HT2A receptor activation on the increases in extracellular glutamate and the subsequent long-term loss of parvalbumin interneurons in the dentate gyrus caused by MDMA. Administration of MDMA into the dentate gyrus of rats increased PGE2 concentrations which was prevented by coadministration of MDL100907, a 5HT2A receptor antagonist. MDMA-induced increases in extracellular glutamate were inhibited by local administration of SC-51089, an inhibitor of the EP1 prostaglandin receptor. Systemic administration of SC-51089 during injections of MDMA prevented the decreases in parvalbumin interneurons observed 10 days later. The loss of parvalbumin immunoreactivity after MDMA exposure coincided with a decrease in paired-pulse inhibition and afterdischarge threshold in the dentate gyrus. These changes were prevented by inhibition of EP1 and 5HT2A receptors during MDMA. Additional experiments revealed an increased susceptibility to kainic acid-induced seizures in MDMA treated rats which could be prevented with SC51089 treatments during MDMA exposure. Overall, these findings suggest that 5HT2A receptors mediate MDMA-induced PGE2 signaling and subsequent increases in glutamate. This signaling mediates parvalbumin cell losses as well as physiologic changes in the dentate gyrus, suggesting that the lack of the inhibition provided by these neurons increases the excitability within the dentate gyrus of MDMA treated rats. PMID:26670377

  18. Aripiprazole Increases the PKA Signalling and Expression of the GABAA Receptor and CREB1 in the Nucleus Accumbens of Rats.

    PubMed

    Pan, Bo; Lian, Jiamei; Huang, Xu-Feng; Deng, Chao

    2016-05-01

    The GABAA receptor is implicated in the pathophysiology of schizophrenia and regulated by PKA signalling. Current antipsychotics bind with D2-like receptors, but not the GABAA receptor. The cAMP-responsive element-binding protein 1 (CREB1) is also associated with PKA signalling and may be related to the positive symptoms of schizophrenia. This study investigated the effects of antipsychotics in modulating D2-mediated PKA signalling and its downstream GABAA receptors and CREB1. Rats were treated orally with aripiprazole (0.75 mg/kg, ter in die (t.i.d.)), bifeprunox (0.8 mg/kg, t.i.d.), haloperidol (0.1 mg/kg, t.i.d.) or vehicle for 1 week. The levels of PKA-Cα and p-PKA in the prefrontal cortex (PFC), nucleus accumbens (NAc) and caudate putamen (CPu) were detected by Western blots. The mRNA levels of Gabrb1, Gabrb2, Gabrb3 and Creb1, and their protein expression were measured by qRT-PCR and Western blots, respectively. Aripiprazole elevated the levels of p-PKA and the ratio of p-PKA/PKA in the NAc, but not the PFC and CPu. Correlated with this elevated PKA signalling, aripiprazole elevated the mRNA and protein expression of the GABAA (β-1) receptor and CREB1 in the NAc. While haloperidol elevated the levels of p-PKA and the ratio of p-PKA/PKA in both NAc and CPu, it only tended to increase the expression of the GABAA (β-1) receptor and CREB1 in the NAc, but not the CPu. Bifeprunox had no effects on PKA signalling in these brain regions. These results suggest that aripiprazole has selective effects on upregulating the GABAA (β-1) receptor and CREB1 in the NAc, probably via activating PKA signalling.

  19. CXC and CC Chemokines as Angiogenic Modulators in Nonhaematological Tumors

    PubMed Central

    Bracarda, Sergio; Nabissi, Massimo; Massari, Francesco; Bria, Emilio; Tortora, Giampaolo; Santoni, Giorgio; Cascinu, Stefano

    2014-01-01

    Chemokines are a superfamily of structurally homologous heparin-binding proteins that includes potent inducers and inhibitors of angiogenesis. The imbalance between angiogenic and angiostatic chemokine activities can lead to abnormalities, such as chronic inflammation, dysplastic transformation, and even tumor development and spreading. In this review, we summarize the current literature regarding the role of chemokines as modulators of tumor angiogenesis and their potential role as therapeutic targets in patients with nonhaematological tumors. PMID:24971349

  20. Increased susceptibility to Salmonella infection in signal regulatory protein α-deficient mice.

    PubMed

    Li, Lin-Xi; Atif, Shaikh M; Schmiel, Shirdi E; Lee, Seung-Joo; McSorley, Stephen J

    2012-09-01

    Recent studies have shed light on the connection between elevated erythropoetin production/spleen erythropoiesis and increased susceptibility to Salmonella infection. In this article, we provide another mouse model, the SIRPα-deficient (Sirpα⁻/⁻) mouse, that manifests increased erythropoiesis as well as heightened susceptibility to Salmonella infection. Sirpα⁻/⁻ mice succumbed to systemic infection with attenuated Salmonella, possessing significantly higher bacterial loads in both the spleen and the liver. Moreover, Salmonella-specific Ab production and Ag-specific CD4 T cells were reduced in Sirpα⁻/⁻ mice compared with wild-type controls. To further characterize the potential mechanism underlying SIRPα-dependent Ag-specific CD4 T cell priming, we demonstrate that lack of SIRPα expression on dendritic cells results in less efficient Ag processing and presentation in vitro. Collectively, these findings demonstrate an indispensable role of SIRPα for protective immunity to Salmonella infection.

  1. Spectral Analysis of the Signals Associated with Increased Activity in Popocatepetl Volcano April 2012

    NASA Astrophysics Data System (ADS)

    Cuenca, J.

    2013-05-01

    After several decades of being inactive in 1994 had a strong reactivation. Since then he has had long periods where volcanic activity including increased growth and destruction of a dome. In April 2012 Popocatepetl Volcano activity showed an increase in the emission of gas and ash, and Vulcanian type explosions. As a result the National Center for Disaster Prevention (CENAPRED) raised the yellow phase from 2 to 3. Spectrally analyzes seismic activity characteristic of the types of events (explosions, LP, Type-B and tremors) that provides information of the source processes that cause it, despite sustained change reflected by the complexity of the volcanic apparatus, through of: 1) the spectral content of the process provides the source, 2) the spectral ratio H / V, its associated amplification and dominant frequencies, 3) time frequency analysis showing the variation in frequency, 4) the particle motion to analyze its retrograde or prograde acting in a volcanic complex medium. The calculation of H / V was performed by each hour using windows with duration of 80 seconds in the broadband seismic station "Canario" (PPPB). The predominant frequencies of H / V are around 1.4-1.8 Hz to 2.1-2.6 Hz and amplifications from 2.3 to 6.9 times. Analysis of H / V of 48 hours (days 16 and April 17) for the case of 1.4-1.8 Hz was observed: (1) From 0-9 hours there is no amplification. (2) The seismic amplification increases from 10 to 11 hours. (3) A first crisis reaches a maximum at 13 hours with about 6 times of amplification. (4) From 14 to 15 hours there is a strong relaxation of the activity. (5) The activity begins to increase from 16 to 23 hours where it reaches its maximum amplification of almost 7 times. (6) The following two hours and is kept exceeding 6 times of amplification. (7) Then is followed by a decrease to 4 hours on the day 17, from which is maintained at a level variable. (8) At 18 hours of the day 17 grows the amplification at 6.2 times, which conforms a

  2. Approaches to Increasing Surface Stress for Improving Signal-to-Noise Ratio of Microcantilever Sensors

    PubMed Central

    Ji, Hai-Feng; Armon, Benjamin D.

    2010-01-01

    Summary Microcantilever sensor technology has been steadily growing for the last fifteen years. While we have gained a great amount of knowledge in microcantilever bending due to surface stress changes, which is a unique property of microcantilever sensors, we are still in the early stages of understanding the fundamental surface chemistries of surface-stress-based microcantilever sensors. In general, increasing surface stress, which is caused by interactions on the microcantilever surfaces, would improve the S/N ratio, and subsequently the sensitivity and reliability of microcantilever sensors. In this review, we will summarize: A) the conditions under which a large surface stress can readily be attained, and B) the strategies to increase surface stress in case a large surface stress can not readily be reached. We will also discuss our perspectives on microcantilever sensors based on surface stress changes. PMID:20128621

  3. Pam2 lipopeptides systemically increase myeloid-derived suppressor cells through TLR2 signaling

    SciTech Connect

    Maruyama, Akira; Shime, Hiroaki Takeda, Yohei; Azuma, Masahiro; Matsumoto, Misako; Seya, Tsukasa

    2015-02-13

    Myeloid-derived suppressor cells (MDSCs) are immature myeloid cells that exhibit potent immunosuppressive activity. They are increased in tumor-bearing hosts and contribute to tumor development. Toll-like receptors (TLRs) on MDSCs may modulate the tumor-supporting properties of MDSCs through pattern-recognition. Pam2 lipopeptides represented by Pam2CSK4 serve as a TLR2 agonist to exert anti-tumor function by dendritic cell (DC)-priming that leads to NK cell activation and cytotoxic T cell proliferation. On the other hand, TLR2 enhances tumor cell progression/invasion by activating tumor-infiltrating macrophages. How MDSCs respond to TLR2 agonists has not yet been determined. In this study, we found intravenous administration of Pam2CSK4 systemically up-regulated the frequency of MDSCs in EG7 tumor-bearing mice. The frequency of tumor-infiltrating MDSCs was accordingly increased in response to Pam2CSK4. MDSCs were not increased by Pam2CSK4 stimuli in TLR2 knockout (KO) mice. Adoptive transfer experiments using CFSE-labeled MDSCs revealed that the TLR2-positive MDSCs survived long in tumor-bearing mice in response to Pam2CSK4 treatment. Since the increased MDSC population sustained immune-suppressive properties, our study suggests that Pam2CSK4-triggered TLR2 activation enhances the MDSC potential and suppress antitumor immune response in tumor microenvironment. - Highlights: • Pam2CSK4 administration induces systemic accumulation of CD11b{sup +}Gr1{sup +} MDSCs. • TLR2 is essential for Pam2CSK4-induced accumulation of CD11b{sup +}Gr1{sup +} MDSCs. • Pam2CSK4 supports survival of CD11b{sup +}Gr1{sup +} MDSCs in vivo.

  4. Transient Oxygen/Glucose Deprivation Causes a Delayed Loss of Mitochondria and Increases Spontaneous Calcium Signaling in Astrocytic Processes

    PubMed Central

    O'Donnell, John C.; Jackson, Joshua G.

    2016-01-01

    Recently, mitochondria have been localized to astrocytic processes where they shape Ca2+ signaling; this relationship has not been examined in models of ischemia/reperfusion. We biolistically transfected astrocytes in rat hippocampal slice cultures to facilitate fluorescent confocal microscopy, and subjected these slices to transient oxygen/glucose deprivation (OGD) that causes delayed excitotoxic death of CA1 pyramidal neurons. This insult caused a delayed loss of mitochondria from astrocytic processes and increased colocalization of mitochondria with the autophagosome marker LC3B. The losses of neurons in area CA1 and mitochondria in astrocytic processes were blocked by ionotropic glutamate receptor (iGluR) antagonists, tetrodotoxin, ziconotide (Ca2+ channel blocker), two inhibitors of reversed Na+/Ca2+ exchange (KB-R7943, YM-244769), or two inhibitors of calcineurin (cyclosporin-A, FK506). The effects of OGD were mimicked by NMDA. The glutamate uptake inhibitor (3S)-3-[[3-[[4-(trifluoromethyl)benzoyl]amino]phenyl]methoxy]-l-aspartate increased neuronal loss after OGD or NMDA, and blocked the loss of astrocytic mitochondria. Exogenous glutamate in the presence of iGluR antagonists caused a loss of mitochondria without a decrease in neurons in area CA1. Using the genetic Ca2+ indicator Lck-GCaMP-6S, we observed two types of Ca2+ signals: (1) in the cytoplasm surrounding mitochondria (mitochondrially centered) and (2) traversing the space between mitochondria (extramitochondrial). The spatial spread, kinetics, and frequency of these events were different. The amplitude of both types was doubled and the spread of both types changed by ∼2-fold 24 h after OGD. Together, these data suggest that pathologic activation of glutamate transport and increased astrocytic Ca2+ through reversed Na+/Ca2+ exchange triggers mitochondrial loss and dramatic increases in Ca2+ signaling in astrocytic processes. SIGNIFICANCE STATEMENT Astrocytes, the most abundant cell type in the

  5. Cocaine increases dopaminergic neuron and motor activity via midbrain α1 adrenergic signaling.

    PubMed

    Goertz, Richard Brandon; Wanat, Matthew J; Gomez, Jorge A; Brown, Zeliene J; Phillips, Paul E M; Paladini, Carlos A

    2015-03-13

    Cocaine reinforcement is mediated by increased extracellular dopamine levels in the forebrain. This neurochemical effect was thought to require inhibition of dopamine reuptake, but cocaine is still reinforcing even in the absence of the dopamine transporter. Here, we demonstrate that the rapid elevation in dopamine levels and motor activity elicited by cocaine involves α1 receptor activation within the ventral midbrain. Activation of α1 receptors increases dopaminergic neuron burst firing by decreasing the calcium-activated potassium channel current (SK), as well as elevates dopaminergic neuron pacemaker firing through modulation of both SK and the hyperpolarization-activated cation currents (Ih). Furthermore, we found that cocaine increases both the pacemaker and burst-firing frequency of rat ventral-midbrain dopaminergic neurons through an α1 adrenergic receptor-dependent mechanism within the ventral tegmental area and substantia nigra pars compacta. These results demonstrate the mechanism underlying the critical role of α1 adrenergic receptors in the regulation of dopamine neurotransmission and behavior by cocaine.

  6. Inflammatory chemokines and their receptors in human visceral leishmaniasis: Gene expression profile in peripheral blood, splenic cellular sources and their impact on trafficking of inflammatory cells.

    PubMed

    Singh, Neetu; Sundar, Shyam

    2017-02-18

    Chemokines play an important role in determining cellular composition at inflammatory sites, and as such, influence disease outcome. In this study, we investigated the expression profile and splenic cellular source of various inflammatory chemokines and their receptors in human visceral leishmaniasis (VL). The expression of chemokines or their receptors was measured at the gene and protein level by employing real time qPCR and a cytometric bead array assay, respectively. In addition, the cellular source of chemokines and their receptors in the spleen was identified employing gene expression analyses in sequentially selected cell subsets. We identified elevated expression of CXCL10, CXCL9, CXCL8, and decreased CCL2 from VL patients. Further, we found reduced expression of the chemokine receptors CXCR1, CXCR2, CXCR3 and CCR2, but increased expression of CCR7 on VL PBMC, compared to endemic healthy controls. Additionally, splenic monocytes were found to be the major source of CXCL10, CXCL9 and CCR2, whereas T cells were the main source of CXCR3 and CCR7. We also report a strong association between plasma IFN-γ and CXCL-10, CXCL-9 levels. Enhanced parasite burden positively correlates with increased expression of CXCL10, CXCL9, IFN-γ and IL-10. Overall our result indicates that VL patients have an elevated inflammatory chemokine milieu which correlated with disease severity. However, expression of their chemokine receptors was significantly impaired, which may have contributed to reduced frequencies of blood monocytes and neutrophils in peripheral blood. In contrast, enhanced expression of CCR7 was associated with increased numbers of activated T cells in circulation. These findings highlight the importance of chemokines for recruitment of various cell populations in VL, and the knowledge gained may help in global understandings of the complex interaction between chemokines and pathological processes, and therefore will contribute towards the design of novel

  7. High-glucose and advanced glycosylation end products increased podocyte permeability via PI3-K/Akt signaling.

    PubMed

    Ha, Tae-Sun

    2010-04-01

    Regardless of the underlying disease, the proteinuric condition demonstrates ultrastructural changes in podocytes with retraction and effacement of the highly specialized interdigitating foot processes. To investigate how high-glucose (HG) and advanced glycosylation end products (AGE) induce podocyte phenotypical changes, including quantitative and distributional changes of zonula occludens (ZO)-1 protein and search for the signaling mechanisms, we cultured rat glomerular epithelial cells (GEpC) and mouse podocytes under: (1) normal glucose (5 mM, control); (2) HG (30 mM); (3) AGE-added; or (4) HG plus AGE-added conditions. HG plus AGE increased the permeability of monolayered GEpCs and induced ultrastructural separation between confluent GEpCs. ZO-1 moved to inner actin filament complexes in both AGE- and/or HG by confocal imaging. HG plus AGE-added condition also decreased ZO-1 protein amount and mRNA expression compared to normal glucose or osmotic control conditions. We could also confirm the induction of RAGE (receptor for AGE) and PI3-K/Akt signaling pathway by AGE and HG. In addition, LY294002, a PI3-K inhibitor, could prevent the quantitative and distributional changes of ZO-1 and RAGE and the increased permeability induced by HG and AGE. These findings suggest that diabetic conditions induce the podocyte ZO-1 changes via RAGE and PI3-K/Akt signaling, leading to increased permeability.

  8. Dysregulated Glycine Signaling Contributes to Increased Impulsivity during Protracted Alcohol Abstinence.

    PubMed

    Irimia, Cristina; Buczynski, Matthew W; Natividad, Luis A; Laredo, Sarah A; Avalos, Nathaniel; Parsons, Loren H

    2017-02-15

    Persons with alcoholism who are abstinent exhibit persistent impairments in the capacity for response inhibition, and this form of impulsivity is significantly associated with heightened relapse risk. Brain-imaging studies implicate aberrant prefrontal cortical function in this behavioral pathology, although the underlying mechanisms are not understood. Here we present evidence that deficient activation of glycine and serine release in the ventral medial prefrontal cortex (vmPFC) contributes to increased motor impulsivity during protracted abstinence from long-term alcohol exposure. Levels of 12 neurotransmitters were monitored in the rat vmPFC during the performance of a challenging variant of the five-choice serial reaction time task (5-CSRTT) in which alcohol-exposed rats exhibit excessive premature responding. Following long-term ethanol exposure, rats showed blunted task-related recruitment of vmPFC glycine and serine release, and the loss of an inverse relationship between levels of these neurotransmitters and premature responding normally evident in alcohol-naive subjects. Intra-vmPFC administration of the glycine transport inhibitor ALX5407 prevented excessive premature responding by alcohol-exposed rats, and this was reliant on NMDA glycine site availability. Alcohol-exposed rats and controls did not differ in their premature responding and glycine and serine levels in vmPFC during the performance of the standard 5-CSRTT. Collectively, these findings provide novel insight into cortical neurochemical mechanisms contributing to increased impulsivity following long-term alcohol exposure and highlight the NMDA receptor coagonist site as a potential therapeutic target for increased impulsivity that may contribute to relapse risk.SIGNIFICANCE STATEMENT Persons with alcoholism demonstrate increased motor impulsivity during abstinence; however, the neuronal mechanisms underlying these behavioral effects remain unknown. Here, we took advantage of an animal model

  9. Chemokines: key players in cancer progression and metastasis

    PubMed Central

    Singh, Rajesh; Lilladr, James W.; Singh, Shailesh

    2013-01-01

    Instructed cell migration is a fundamental component of various biological systems and is critical to the pathogenesis of many diseases including cancer. Role of chemokines in providing navigational cues to migrating cancer cells bearing specific receptors is well established. However, functional mechanisms of chemokine are not well implicit, which is crucial for designing new therapeutics to control tumor growth and metastasis. Multiple functions and mode of actions have been advocated for chemokines and their receptors in the progression of primary and secondary tumors. In this review, we have discussed current advances in understanding the role of the chemokines and their corresponding receptor in tumor progression and metastasis. PMID:21622291

  10. Human β defensin-3 induces chemokines from monocytes and macrophages: diminished activity in cells from HIV-infected persons.

    PubMed

    Petrov, Velizar; Funderburg, Nicholas; Weinberg, Aaron; Sieg, Scott

    2013-12-01

    Human β defensin-3 (hBD-3) is an antimicrobial peptide with diverse functionality. We investigated the capacity of hBD-3 and, for comparison, Pam3CSK4 and LL-37 to induce co-stimulatory molecules and chemokine expression in monocytes. These stimuli differentially induced CD80 and CD86 on the surface of monocytes and each stimulant induced a variety of chemokines including monocyte chemoattractant protein 1 (MCP-1), Gro-α, macrophage-derived chemokine (MDC) and macrophage inflammatory protein 1β (MIP1β), while only hBD-3 and Pam3CSK4 significantly induced the angiogenesis factor, vascular endothelial growth factor (VEGF). Human BD-3 induced similar chemokines in monocyte-derived macrophages and additionally induced expression of Regulated upon activation normal T-cell expressed and presumably secreted (RANTES) in these cells. Comparison of monocytes from HIV(+) and HIV(-) donors indicated that monocytes from HIV(+) donors were more likely to spontaneously express certain chemokines (MIP-1α, MIP-1β and MCP-1) and less able to increase expression of other molecules in response to hBD-3 (MDC, Gro-α and VEGF). Chemokine receptor expression (CCR5, CCR2 and CXCR2) was relatively normal in monocytes from HIV(+) donors compared with cells from HIV(-) donors with the exception of diminished expression of the receptor for MDC, CCR4, which was reduced in the patrolling monocyte subset (CD14(+)  CD16(++) ) of HIV(+) donors. These observations implicate chemokine induction by hBD-3 as a potentially important mechanism for orchestrating cell migration into inflamed tissues. Alterations in chemokine production or their receptors in monocytes of HIV-infected persons could influence cell migration and modify the effects of hBD-3 at sites of inflammation.

  11. I-TAC is a dominant chemokine in controlling skin intragraft inflammation via recruiting CXCR3+ cells into the graft.

    PubMed

    Li, Baohua; Xu, Wei; Xu, Lin; Jiang, Zhenggang; Wen, Zhenke; Li, Kang; Xiong, Sidong

    2010-01-01

    Chemokines play a critical role in the acute transplant rejection. In order to provide an overview of the chemokine expression during the course of acute allograft rejection, the intragraft expression profile of 11 chemokines representative of all four chemokine subfamilies was analyzed in a murine skin transplantation model of acute rejection. It was found that RANTES/CCL5, TARC/CCL17 and FKN/CX(3)CL1 were expressed at equivalent levels in iso- and allografts. However, the other eight chemokines expression was up-regulated to some extent in allograft compared with that in isograft. The levels of MIP-1alpha/CCL3, MIP-3alpha/CCL20 and CTACK/CCL27 were progressively increased from early stage (day 3 post-transplantation) to late stage (day 11). Mig/CXCL9, IP-10/CXCL10, I-TAC/CXCL11, CXCL16 and LTN/XCL1 expression was elevated at middle stage (day 7), and peaked at late stage. Among the up-regulated chemokines, I-TAC was the most obviously elevated chemokine. Therefore, the effect of I-TAC on the skin acute allograft rejection was evaluated. Block of I-TAC by the intradermal injection of anti-I-TAC monoclonal antibody (mAb) reduced the number of CXCR3(+) cells in skin allograft and significantly prolonged the skin allograft survival. The mAb treatment did not influence the proliferation of the intragraft infiltrating cells in response to the allogeneic antigens, but significantly decreased the number of the infiltrating cells and consequently lowered the secretion of IFN-gamma and TNF-alpha. These data indicate I-TAC might be a dominant chemokine involved in the intradermal infiltration and I-TAC-targeted intervening strategies would have potential application for the alleviation of acute transplant rejection.

  12. Chemokine receptor CXCR7 is a functional receptor for CXCL12 in brain endothelial cells.

    PubMed

    Liu, Yang; Carson-Walter, Eleanor; Walter, Kevin A

    2014-01-01

    The chemokine CXCL12 regulates multiple cell functions through its receptor, CXCR4. However, recent studies have shown that CXCL12 also binds a second receptor, CXCR7, to potentiate signal transduction and cell activity. In contrast to CXCL12/CXCR4, few studies have focused on the role of CXCR7 in vascular biology and its role in human brain microvascular endothelial cells (HBMECs) remains unclear. In this report, we used complementary methods, including immunocytofluorescence, Western blot, and flow cytometry analyses, to demonstrate that CXCR7 was expressed on HBMECs. We then employed short hairpin RNA (shRNA) technology to knockdown CXCR7 in HBMECs. Knockdown of CXCR7 in HBMECs resulted in significantly reduced HBMEC proliferation, tube formation, and migration, as well as adhesion to matrigel and tumor cells. Blocking CXCR7 with a specific antibody or small molecule antagonist similarly disrupted HBMEC binding to matrigel or tumor cells. We found that tumor necrosis factor (TNF)-α induced CXCR7 in a time and dose-response manner and that this increase preceded an increase in vascular cell adhesion molecule-1 (VCAM-1). Knockdown of CXCR7 resulted in suppression of VCAM-1, suggesting that the reduced binding of CXCR7-knockdown HBMECs may result from suppression of VCAM-1. Collectively, CXCR7 acted as a functional receptor for CXCL12 in brain endothelial cells. Targeting CXCR7 in tumor vasculature may provide novel opportunities for improving brain tumor therapy.

  13. Solubility and bioactivity of the Pseudomonas quinolone signal are increased by a Pseudomonas aeruginosa-produced surfactant.

    PubMed

    Calfee, M Worth; Shelton, John G; McCubrey, James A; Pesci, Everett C

    2005-02-01

    Pseudomonas aeruginosa is a gram-negative bacterium that causes serious infections in immunocompromised individuals and cystic fibrosis patients. This opportunistic pathogen controls many of its virulence factors and cellular functions through the activity of three cell-to-cell signals, N-(3-oxododecanoyl)-L-homoserine lactone, N-butyryl-L-homoserine lactone, and the Pseudomonas quinolone signal (PQS). The activity of these signals is dependent upon their ability to dissolve in and freely diffuse through the aqueous solution in which P. aeruginosa happens to reside. Despite this, our data indicated that PQS was relatively insoluble in aqueous solutions, which led us to postulate that P. aeruginosa could be producing a PQS-solubilizing factor. In this report, we show that the P. aeruginosa-produced biosurfactant rhamnolipid greatly enhances the solubility of PQS in aqueous solutions. The enhanced solubility of PQS led to an increase in PQS bioactivity, as measured by both a gene induction assay and an apoptosis assay. This is the first demonstration of the importance of a bacterial surfactant in the solubilization and bioactivity of a cell-to-cell signal.

  14. The great 2006 heat wave over California and Nevada: Signal of an increasing trend

    USGS Publications Warehouse

    Gershunov, A.; Cayan, D.R.; Iacobellis, S.F.

    2009-01-01

    Most of the great California-Nevada heat waves can be classified into primarily daytime or nighttime events depending on whether atmospheric conditions are dry or humid. A rash of nighttime-accentuated events in the last decade was punctuated by an unusually intense case in July 2006, which was the largest heat wave on record (1948-2006). Generally, there is a positive trend in heat wave activity over the entire region that is expressed most strongly and clearly in nighttime rather than daytime temperature extremes. This trend in nighttime heat wave activity has intensified markedly since the 1980s and especially since 2000. The two most recent nighttime heat waves were also strongly expressed in extreme daytime temperatures. Circulations associated with great regional heat waves advect hot air into the region. This air can be dry or moist, depending on whether a moisture source is available, causing heat waves to be expressed preferentially during day or night. A remote moisture source centered within a marine region west of Baja California has been increasing in prominence because of gradual sea surface warming and a related increase in atmospheric humidity. Adding to the very strong synoptic dynamics during the 2006 heat wave were a prolonged stream of moisture from this southwestern source and, despite the heightened humidity, an environment in which afternoon convection was suppressed, keeping cloudiness low and daytime temperatures high. The relative contributions of these factors and possible relations to global warming are discussed. ?? 2009 American Meteorological Society.

  15. Simultaneous measurement of serum chemokines in autoimmune thyroid diseases: possible role of IP-10 in the inflammatory response.

    PubMed

    Hiratsuka, Izumi; Itoh, Mitsuyasu; Yamada, Hiroya; Yamamoto, Keiko; Tomatsu, Eisuke; Makino, Masaki; Hashimoto, Shuji; Suzuki, Atsushi

    2015-01-01

    Autoimmune thyroid diseases (AITDs), including Graves' diseases (GD) and Hashimoto's thyroiditis (HT), are the most common autoimmune diseases, and are mainly mediated by T cells that produce cytokines and chemokines in abnormal amounts. Few reports have described the circulating chemokines active in AITDs. Recently, we used a new multiplex immunobead assay to simultaneously measure cytokines and chemokines in small volume serum samples from patients with AITDs. We measured 23 selected serum chemokines in patients with GD (n=45) or HT (n=26), and healthy controls (n=9). GD patients were further classified as either untreated, intractable, or in remission, while HT patients were classified as either hypothyroid or euthyroid. Of the 23 serum chemokines assayed, only the serum level of IP-10 (CXCL10/interferon-γ-inducible protein 10) was elevated, depending on disease activity, in GD or HT compared with healthy controls. However, the serum level of IP-10 was also increased in both untreated GD patients and hypothyroid HT patients, suggesting that levels of this cytokine may not be affected by disease specificity. In conclusion, autoimmune inflammation in patients with AITD is closely related to the level of the serum chemokine, IP-10. Therefore, IP-10 might be a good biomarker for tissue inflammation in the thyroid, but not a useful biomarker for predicting disease specific activity, the progression of AITDs, or responsiveness to treatment because of its independence from thyroid function or disease specificity.

  16. Characterization and expression analysis of an interferon-γ2 induced chemokine receptor CXCR3 in common carp (Cyprinus carpio L.).

    PubMed

    Chadzinska, M; Golbach, L; Pijanowski, L; Scheer, M; Verburg-van Kemenade, B M L

    2014-11-01

    Chemokine and chemokine receptor signalling pairs play a crucial role in regulation of cell migration, morphogenesis, and cell activation. Expressed in mammals on activated T and NK cells, chemokine receptor CXCR3 binds interferon-γ inducible chemokines CXCL9-11 and CCL21. Here we sequenced the carp CXCR3 chemokine receptor and showed its relationship to CXCR3a receptors found in other teleosts. We found high expression of the CXCR3 gene in most of the organs and tissues of the immune system and in immune-related tissues such as gills and gut, corroborating a predominantly immune-related function. The very high expression in gill and gut moreover indicates a role for CXCR3 in cell recruitment during infection. High in vivo expression of CXCR3 at later stages of inflammation, as well as its in vitro sensitivity to IFN-γ2 stimulation indicate that in carp, CXCR3 is involved in macrophage-mediated responses. Moreover, as expression of the CXCR3 and CXCb genes coincides in the focus of inflammation and as both the CXCb chemokines and the CXCR3 receptor are significantly up-regulated upon IFN-γ stimulation it is hypothesized that CXCb chemokines may be putative ligands for CXCR3.

  17. Increasing leucine concentration stimulates mechanistic target of rapamycin signaling and cell growth in C2C12 skeletal muscle cells.

    PubMed

    Areta, José L; Hawley, John A; Ye, Ji-Ming; Chan, M H Stanley; Coffey, Vernon G

    2014-11-01

    Leucine is a key amino acid for initiating translation in muscle cells, but the dose-dependent effects of leucine on intracellular signaling are poorly characterized. This study examined the effect that increasing doses of leucine would have on changes in mechanistic target of rapamycin (mTOR)-mediated signaling, rates of protein synthesis, and cell size in C2C12 cells. We hypothesized that a leucine "threshold" exists, which represents the minimum stimulus required to initiate mTOR signaling in muscle cells. Acute exposure to 1.5, 3.2, 5.0, and 16.1 mM leucine increased phosphorylation of mTOR(Ser2448) (~1.4-fold; P < .04), 4E-BP1 (Thr37/46) (~1.9-fold; P < .001), and rpS6(Ser235/6) (~2.3-fold; P < .001). However, only p70S6k(Thr389) exhibited a dose-dependent response to leucine with all treatments higher than control (~4-fold; P < .001) and at least 5 mM higher than the 1.5-mM concentration (1.2-fold; P < .02). Rates of protein synthesis were not altered by any treatment. Seven days of exposure to 0.5, 1.5, 5.0, and 16.5 mM leucine resulted in an increase in cell size in at least 5 mM treatments (~1.6-fold, P < .001 vs control). Our findings indicate that even at low leucine concentrations, phosphorylation of proteins regulating translation initiation signaling is enhanced. The phosphorylation of p70S6k(Thr389) follows a leucine dose-response relationship, although this was not reflected by the acute protein synthetic response. Nevertheless, under the conditions of the present study, it appears that leucine concentrations of at least 5 mM are necessary to enhance cell growth.

  18. Calcium spike-mediated digital signaling increases glutamate output at the visual threshold of retinal bipolar cells

    PubMed Central

    Lipin, Mikhail Y.

    2014-01-01

    Most retinal bipolar cells (BCs) transmit visual input from photoreceptors to ganglion cells using graded potentials, but some also generate calcium or sodium spikes. Sodium spikes are thought to increase temporal precision of light-evoked BC signaling; however, the role of calcium spikes in BCs is not fully understood. Here we studied how calcium spikes and graded responses mediate neurotransmitter release from Mb-type BCs, known to produce both. In dark-adapted goldfish retinal slices, light induced spikes in 40% of the axon terminals of intact Mbs; in the rest, light generated graded responses. These light-evoked membrane potentials were used to depolarize axotomized Mb terminals where depolarization-evoked calcium current (ICa) and consequent exocytosis-associated membrane capacitance increases (ΔCm) could be precisely measured. When evoked by identical dim light intensities, spiking responses transferred more calcium (QCa) and triggered larger exocytosis with higher efficiency (ΔCm/QCa) than graded potentials. QCa was translated into exocytosis linearly when transferred with spikes and supralinearly when transferred with graded responses. At the Mb output (ΔCm), spiking responses coded light intensity with numbers and amplitude whereas graded responses coded with amplitude, duration, and steepness. Importantly, spiking responses saturated exocytosis within scotopic range but graded potentials did not. We propose that calcium spikes in Mbs increase signal input-output ratio by boosting Mb glutamate release at threshold intensities. Therefore, spiking Mb responses are suitable to transfer low-light-intensity signals to ganglion cells with higher gain, whereas graded potentials signal for light over a wider range of intensities at the Mb output. PMID:25339710

  19. Pouncing on the chemokine receptor Chimera.

    PubMed

    Mascolini, M

    1997-08-01

    Scientists are seeking to unravel the mystery of chemokine receptors in an attempt to develop treatments for HIV infection; however, receptor experts are realizing that the picture is more complicated than they first imagined. Scientists want to know, among other things, what parts of each coreceptor are essential for viral fusion with target cells, what makes macrophage-tropic viruses switch their preference to T-lymphocytes, why HIV goes after chemokine receptors in the first place, and how fusion and entry occur. Other issues discussed include whether blocking coreceptors for HIV will actually curb this disease, virus turnover in monkey studies showing that SIV may go through the cycle as many as 100 times per day, and studies showing that the first days of infection may predict the course of disease. Final comments concern the use of ritonavir plus indinavir in treatment combinations for children with HIV and the latest progress toward vaccine development. Understanding these and other puzzles might help scientists to develop drugs to block receptors active in HIV infection and perhaps curb HIV. More than 14 biotechnology and pharmaceutical firms are working to design coreceptor blockers, despite the opinions of several leading researchers that the drugs are not terribly promising. Dr. Anthony Fauci, director of the National Institute for Allergy and Infectious Disease (NIAID), notes that a famous attempt to block HIV's primary receptor failed, and David Ho, the man who demonstrated why CD4 would not work as therapy, is similarly cautious. According to Ho, drug makers will have no trouble developing compounds that keep HIV off chemokine receptors, such as CCR5 or CXCR4, but whether those compounds will slow disease progression is another question.

  20. GRK2 blockade with βARKct is essential for cardiac β2-adrenergic receptor signaling towards increased contractility

    PubMed Central

    2013-01-01

    Background β1- and β2–adrenergic receptors (ARs) play distinct roles in the heart, e.g. β1AR is pro-contractile and pro-apoptotic but β2AR anti-apoptotic and only weakly pro-contractile. G protein coupled receptor kinase (GRK)-2 desensitizes and opposes βAR pro-contractile signaling by phosphorylating the receptor and inducing beta-arrestin (βarr) binding. We posited herein that GRK2 blockade might enhance the pro-contractile signaling of the β2AR subtype in the heart. We tested the effects of cardiac-targeted GRK2 inhibition in vivo exclusively on β2AR signaling under normal conditions and in heart failure (HF). Results We crossed β1AR knockout (B1KO) mice with cardiac-specific transgenic mice expressing the βARKct, a known GRK2 inhibitor, and studied the offspring under normal conditions and in post-myocardial infarction (MI). βARKct expression in vivo proved essential for β2AR-dependent contractile function, as β2AR stimulation with isoproterenol fails to increase contractility in either healthy or post-MI B1KO mice and it only does so in the presence of βARKct. The main underlying mechanism for this is blockade of the interaction of phosphodiesterase (PDE) type 4D with the cardiac β2AR, which is normally mediated by the actions of GRK2 and βarrs on the receptor. The molecular “brake” that PDE4D poses on β2AR signaling to contractility stimulation is thus “released”. Regarding the other beneficial functions of cardiac β2AR, βARKct increased overall survival of the post-MI B1KO mice progressing to HF, via a decrease in cardiac apoptosis and an increase in wound healing-associated inflammation early (at 24 hrs) post-MI. However, these effects disappear by 4 weeks post-MI, and, in their place, upregulation of the other major GRK in the heart, GRK5, is observed. Conclusions GRK2 inhibition in vivo with βARKct is absolutely essential for cardiac β2AR pro-contractile signaling and function. In addition, β2AR anti-apoptotic signaling in

  1. Increasing JAK/STAT Signaling Function of Infant CD4+ T Cells during the First Year of Life

    PubMed Central

    dela Peña-Ponce, Myra Grace; Rodriguez-Nieves, Jennifer; Bernhardt, Janice; Tuck, Ryan; Choudhary, Neelima; Mengual, Michael; Mollan, Katie R.; Hudgens, Michael G.; Peter-Wohl, Sigal; De Paris, Kristina

    2017-01-01

    Most infant deaths occur in the first year of life. Yet, our knowledge of immune development during this period is scarce and derived from cord blood (CB) only. To more effectively combat pediatric diseases, a deeper understanding of the kinetics and the factors that regulate the maturation of immune functions in early life is needed. Increased disease susceptibility of infants is generally attributed to T helper 2-biased immune responses. The differentiation of CD4+ T cells along a specific T helper cell lineage is dependent on the pathogen type, and on costimulatory and cytokine signals provided by antigen-presenting cells. Cytokines also regulate many other aspects of the host immune response. Therefore, toward the goal of increasing our knowledge of early immune development, we defined the temporal development of the Janus kinase (JAK)/signal transducers and activators of transcription (STAT) signaling function of CD4+ T cells using cross-sectional blood samples from healthy infants ages 0 (birth) to 14 months. We specifically focused on cytokines important in T cell differentiation (IFN-γ, IL-12, and IL-4) or in T cell survival and expansion (IL-2 and IL-7) in infant CD4+ T cells. Independent of the cytokine tested, JAK/STAT signaling in infant compared to adult CD4+ T cells was impaired at birth, but increased during the first year, with the most pronounced changes occurring in the first 6 months. The relative change in JAK/STAT signaling of infant CD4+ T cells with age was distinct for each cytokine tested. Thus, while about 60% of CB CD4+ T cells could efficiently activate STAT6 in response to IL-4, less than 5% of CB CD4+ T cells were able to activate the JAK/STAT pathway in response to IFN-γ, IL-12 or IL-2. By 4–6 months of age, the activation of the cytokine-specific STAT molecules was comparable to adults in response to IL-4 and IFN-γ, while IL-2- and IL-12-induced STAT activation remained below adult levels even at 1 year. These results

  2. The role of the chemokine receptor XCR1 in breast cancer cells

    PubMed Central

    Yang, Xiao Li; Qi, Li Guo; Lin, Feng Juan; Ou, Zhou Luo

    2017-01-01

    Considerable attention has recently been paid to the application of chemokines to cancer immunotherapy due to their complex role in cell proliferation, invasion, metastasis, and tumorigenesis, which extends beyond the regulation of lymphocyte migration during immune responses. The expression and the function of the chemokine receptor XCR1 on breast cancer have remained elusive to date. In this study, the expressions of XCR1 mRNA were tested by quantitative real-time polymerase chain reaction in one breast epithelial cell line (MCF-10A) and nine breast cancer cell lines (MDA-MB-231, 231HM, 231BO, MDA-MB-468, MCF-7, T47D, Bcap-37, ZR-75-30, and SK-BR-3). We established XCR1-overexpressing breast cancer cell line MDA-MB-231 (231/XCR1) in XCR1 low expression cell line MDA-MB-231 (231). The ability of proliferation, invasion, and metastasis was measured by CCK8, plate cloning formation, and transwell analysis, respectively, in XCR1-overexpressing breast cancer cell lines (231/XCR1) and their parental cell line MDA-MB-231/Vector (simplified as “231/Vector”); 5×106/100 μL cells were inoculated in mammary fat pad of BALB/c nude mice. There were six BALB/c nude mice in the experimental group and control group. Protein expression was analyzed by cell immunofluorescence and Western blot. The growth of XCR1-overexpressing human breast cancer cell line MDA-MB-231 in vitro was restrained and tumorigenesis in vivo was also extenuated, its mechanism may involve in the inhibition of MAPK and PI3K/AKT/mTOR signaling pathway, but increase in LC3 expression. However, the overexpression of XCR1 in human breast cancer cell line MDA-MB-231 in vitro can promote the migration and invasion partially due to decreasing the protein level of β-catenin. Therefore, XCR1 can affect the biological characteristics of some special breast cancer cells through complex signal transduction pathway.

  3. Serum amyloid A chemoattracts immature dendritic cells and indirectly provokes monocyte chemotaxis by induction of cooperating CC and CXC chemokines.

    PubMed

    Gouwy, Mieke; De Buck, Mieke; Pörtner, Noëmie; Opdenakker, Ghislain; Proost, Paul; Struyf, Sofie; Van Damme, Jo

    2015-01-01

    Serum amyloid A (SAA) is an acute phase protein that is upregulated in inflammatory diseases and chemoattracts monocytes, lymphocytes, and granulocytes via its G protein-coupled receptor formyl peptide receptor like 1/formyl peptide receptor 2 (FPRL1/FPR2). Here, we demonstrated that the SAA1α isoform also chemoattracts monocyte-derived immature dendritic cells (DCs) in the Boyden and μ-slide chemotaxis assay and that its chemotactic activity for monocytes and DCs was indirectly mediated via rapid chemokine induction. Indeed, SAA1 induced significant amounts (≥5 ng/mL) of macrophage inflammatory protein-1α/CC chemokine ligand 3 (MIP-1α/CCL3) and interleukin-8/CXC chemokine ligand 8 (IL-8/CXCL8) in monocytes and DCs in a dose-dependent manner within 3 h. However, SAA1 also directly activated monocytes and DCs for signaling and chemotaxis without chemokine interference. SAA1-induced monocyte migration was nevertheless significantly prevented (60-80% inhibition) in the constant presence of desensitizing exogenous MIP-1α/CCL3, neutralizing anti-MIP-1α/CCL3 antibody, or a combination of CC chemokine receptor 1 (CCR1) and CCR5 antagonists, indicating that this endogenously produced CC chemokine was indirectly contributing to SAA1-mediated chemotaxis. Further, anti-IL-8/CXCL8 antibody neutralized SAA1-induced monocyte migration, suggesting that endogenous IL-8/CXCL8 acted in concert with MIP-1α/CCL3. This explained why SAA1 failed to synergize with exogenously added MIP-1α/CCL3 or stromal cell-derived factor-1α (SDF-1α)/CXCL12 in monocyte and DC chemotaxis. In addition to direct leukocyte activation, SAA1 induces a chemotactic cascade mediated by expression of cooperating chemokines to prolong leukocyte recruitment to the inflammatory site.

  4. Pertussis toxin inhibits early chemokine production to delay neutrophil recruitment in response to Bordetella pertussis respiratory tract infection in mice.

    PubMed

    Andreasen, Charlotte; Carbonetti, Nicholas H

    2008-11-01

    Pertussis is an acute respiratory disease of humans caused by the bacterium Bordetella pertussis. Pertussis toxin (PT) plays a major role in the virulence of this pathogen, including important effects that it has soon after inoculation. Studies in our laboratory and other laboratories have indicated that PT inhibits early neutrophil influx to the lungs and airways in response to B. pertussis respiratory tract infection in mice. Previous in vitro and in vivo studies have shown that PT can affect neutrophils directly by ADP ribosylating G(i) proteins associated with surface chemokine receptors, thereby inhibiting neutrophil migration in response to chemokines. However, in this study, by comparing responses to wild-type (WT) and PT-deficient strains, we found that PT has an indirect inhibitory effect on neutrophil recruitment to the airways in response to infection. Analysis of lung chemokine expression indicated that PT suppresses early neutrophil recruitment by inhibiting chemokine upregulation in alveolar macrophages and other lung cells in response to B. pertussis infection. Enhancement of early neutrophil recruitment to the airways in response to WT infection by addition of exogenous keratinocyte-derived chemokine, one of the dominant neutrophil-attracting chemokines in mice, further revealed an indirect effect of PT on neutrophil chemotaxis. Additionally, we showed that intranasal administration of PT inhibits lipopolysaccharide-induced chemokine gene expression and neutrophil recruitment to the airways, presumably by modulation of signaling through Toll-like receptor 4. Collectively, these results demonstrate how PT inhibits early inflammatory responses in the respiratory tract, which reduces neutrophil influx in response to B. pertussis infection, potentially providing an advantage to the pathogen in this interaction.

  5. Adolescent caffeine consumption increases adulthood anxiety-related behavior and modifies neuroendocrine signaling.

    PubMed

    O'Neill, Casey E; Newsom, Ryan J; Stafford, Jacob; Scott, Talia; Archuleta, Solana; Levis, Sophia C; Spencer, Robert L; Campeau, Serge; Bachtell, Ryan K

    2016-05-01

    Caffeine is a commonly used psychoactive substance and consumption by children and adolescents continues to rise. Here, we examine the lasting effects of adolescent caffeine consumption on anxiety-related behaviors and several neuroendocrine measures in adulthood. Adolescent male Sprague-Dawley rats consumed caffeine (0.3g/L) for 28 consecutive days from postnatal day 28 (P28) to P55. Age-matched control rats consumed water. Behavioral testing for anxiety-related behavior began in adulthood (P62) 7 days after removal of caffeine. Adolescent caffeine consumption enhanced anxiety-related behavior in an open field, social interaction test, and elevated plus maze. Similar caffeine consumption in adult rats did not alter anxiety-related behavior after caffeine removal. Characterization of neuroendocrine measures was next assessed to determine whether the changes in anxiety were associated with modifications in the HPA axis. Blood plasma levels of corticosterone (CORT) were assessed throughout the caffeine consumption procedure in adolescent rats. Adolescent caffeine consumption elevated plasma CORT 24h after initiation of caffeine consumption that normalized over the course of the 28-day consumption procedure. CORT levels were also elevated 24h after caffeine removal and remained elevated for 7 days. Despite elevated basal CORT in adult rats that consumed caffeine during adolescence, the adrenocorticotropic hormone (ACTH) and CORT response to placement on an elevated pedestal (a mild stressor) was significantly blunted. Lastly, we assessed changes in basal and stress-induced c-fos and corticotropin-releasing factor (Crf) mRNA expression in brain tissue collected at 7 days withdrawal from adolescent caffeine. Adolescent caffeine consumption increased basal c-fos mRNA in the paraventricular nucleus of the hypothalamus. Adolescent caffeine consumption had no other effects on the basal or stress-induced c-fos mRNA changes. Caffeine consumption during adolescence increased

  6. Swiprosin-1 stimulates cancer invasion and metastasis by increasing the Rho family of GTPase signaling

    PubMed Central

    Huh, Yun Hyun; Oh, Sena; Yeo, Yu Ra; Chae, In Hee; Kim, So Hee; Lee, Ji Shin; Yun, Sook Jung; Choi, Kyu Yeong; Ryu, Je-Hwang; Jun, Chang-Duk; Song, Woo Keun

    2015-01-01

    Ectopic expression of Swiprosin-1, an actin-binding protein (also known as EF hand domain containing 2; EFHD2), enhanced motile protrusions associated with actin, such as lamellipodia and membrane ruffles. Swiprosin-1 levels were increased in various human cancer tissues, particularly at highly invasive stages of malignant melanoma. Expression of Swiprosin-1 was correlated with that of epidermal growth factor receptor (EGFR) and induced by EGF. In a mouse metastasis model, Swiprosin-1 overexpression induced pulmonary metastasis whereas its knockdown led to marked inhibition of metastasis of highly invasive melanoma cells. Swiprosin-1 at the lamellipodia and membrane ruffles controlled the direction of cell protrusion and enhanced migration velocity through activating the Rho family of small GTPases, including Rac1, Cdc42 and RhoA. Our collective findings support the potential utility of Swiprosin-1 as a therapeutic target to prevent cancer invasion and metastasis. PMID:26079945

  7. Diversity and Inter-Connections in the CXCR4 Chemokine Receptor/Ligand Family: Molecular Perspectives

    PubMed Central

    Pawig, Lukas; Klasen, Christina; Weber, Christian; Bernhagen, Jürgen; Noels, Heidi

    2015-01-01

    CXCR4 and its ligand CXCL12 mediate the homing of progenitor cells in the bone marrow and their recruitment to sites of injury, as well as affect processes such as cell arrest, survival, and angiogenesis. CXCL12 was long thought to be the sole CXCR4 ligand, but more recently the atypical chemokine macrophage migration inhibitory factor (MIF) was identified as an alternative, non-cognate ligand for CXCR4 and shown to mediate chemotaxis and arrest of CXCR4-expressing T-cells. This has complicated the understanding of CXCR4-mediated signaling and associated biological processes. Compared to CXCL12/CXCR4-induced signaling, only few details are known on MIF/CXCR4-mediated signaling and it remains unclear to which extent MIF and CXCL12 reciprocally influence CXCR4 binding and signaling. Furthermore, the atypical chemokine receptor 3 (ACKR3) (previously CXCR7) has added to the complexity of CXCR4 signaling due to its ability to bind CXCL12 and MIF, and to evoke CXCL12- and MIF-triggered signaling independently of CXCR4. Also, extracellular ubiquitin (eUb) and the viral protein gp120 (HIV) have been reported as CXCR4 ligands, whereas viral chemokine vMIP-II (Herpesvirus) and human β3-defensin (HBD-3) have been identified as CXCR4 antagonists. This review will provide insight into the diversity and inter-connections in the CXCR4 receptor/ligand family. We will discuss signaling pathways initiated by binding of CXCL12 vs. MIF to CXCR4, elaborate on how ACKR3 affects CXCR4 signaling, and summarize biological functions of CXCR4 signaling mediated by CXCL12 or MIF. Also, we will discuss eUb and gp120 as alternative ligands for CXCR4, and describe vMIP-II and HBD-3 as antagonists for CXCR4. Detailed insight into biological effects of CXCR4 signaling und underlying mechanisms, including diversity of CXCR4 ligands and inter-connections with other (chemokine) receptors, is clinically important, as the CXCR4 antagonist AMD3100 has been approved as stem cell mobilizer in specific

  8. Soluble M3 proteins of murine gammaherpesviruses 68 and 72 expressed in Escherichia coli: analysis of chemokine-binding properties.

    PubMed

    Matúšková, R; Pančík, P; Štibrániová, I; Belvončíková, P; Režuchová, I; Kúdelová, M

    2015-12-01

    M3 protein of murine gammaherpesvirus 68 (MHV-68) was identified as a viral chemokine-binding protein 3 (vCKBP-3) capable to bind a broad spectrum of chemokines and their receptors. During both acute and latent infection MHV-68 M3 protein provides a selective advantage for the virus by inhibiting the antiviral and inflammatory response. A unique mutation Asp307Gly was identified in the M3 protein of murine gammaherpesvirus 72 (MHV-72), localized near chemokine-binding domain. Study on chemokine-binding properties of MHV-72 M3 protein purified from medium of infected cells implied reduced binding to some chemokines when compared to MHV-68 M3 protein. It was suggested that the mutation in the M3 protein might be involved in the attenuation of immune response to infection with MHV-72. Recently, Escherichia coli cells were used to prepare native recombinant M3 proteins of murine gammaherpesviruses 68 and 72 (Pančík et al., 2013). In this study, we assessed the chemokine-binding properties of three M3 proteins prepared in E. coli Rosetta-gami 2 (DE3) cells, the full length M3 protein of both MHV-68 and MHV-72 and MHV-68 M3 protein truncated in the signal sequence (the first 24 aa). They all displayed binding activity to human chemokines CCL5 (RANTES), CXCL8 (IL-8), and CCL3 (MIP-1α). The truncated MHV-68 M3 protein had more than twenty times reduced binding activity to CCL5, but only about five and three times reduced binding to CXCL8 and CCL3 when compared to its full length counterpart. Binding of the full length MHV-72 M3 protein to all chemokines was reduced when compared to MHV-68 M3 protein. Its binding to CCL5 and CCL3 was reduced over ten and seven times. However, its binding to CXCL8 was only slightly reduced (64.8 vs 91.8%). These data implied the significance of the signal sequence and also of a single mutation (at aa 307) for efficient M3 protein binding to some chemokines.

  9. Increased BOLD Signals Elicited by High Gamma Auditory Stimulation of the Left Auditory Cortex in Acute State Schizophrenia.

    PubMed

    Kuga, Hironori; Onitsuka, Toshiaki; Hirano, Yoji; Nakamura, Itta; Oribe, Naoya; Mizuhara, Hiroaki; Kanai, Ryota; Kanba, Shigenobu; Ueno, Takefumi

    2016-10-01

    Recent MRI studies have shown that schizophrenia is characterized by reductions in brain gray matter, which progress in the acute state of the disease. Cortical circuitry abnormalities in gamma oscillations, such as deficits in the auditory steady state response (ASSR) to gamma frequency (>30-Hz) stimulation, have also been reported in schizophrenia patients. In the current study, we investigated neural responses during click stimulation by BOLD signals. We acquired BOLD responses elicited by click trains of 20, 30, 40 and 80-Hz frequencies from 15 patients with acute episode schizophrenia (AESZ), 14 symptom-severity-matched patients with non-acute episode schizophrenia (NASZ), and 24 healthy controls (HC), assessed via a standard general linear-model-based analysis. The AESZ group showed significantly increased ASSR-BOLD signals to 80-Hz stimuli in the left auditory cortex compared with the HC and NASZ groups. In addition, enhanced 80-Hz ASSR-BOLD signals were associated with more severe auditory hallucination experiences in AESZ participants. The present results indicate that neural over activation occurs during 80-Hz auditory stimulation of the left auditory cortex in individuals with acute state schizophrenia. Given the possible association between abnormal gamma activity and increased glutamate levels, our data may reflect glutamate toxicity in the auditory cortex in the acute state of schizophrenia, which might lead to progressive changes in the left transverse temporal gyrus.

  10. Mesenchymal Stem Cells Increase Hippocampal Neurogenesis and Neuronal Differentiation by Enhancing the Wnt Signaling Pathway in an Alzheimer's Disease Model.

    PubMed

    Oh, Se Hee; Kim, Ha Na; Park, Hyun-Jung; Shin, Jin Young; Lee, Phil Hyu

    2015-01-01

    Neurogenesis in the subgranular zone of the hippocampal dentate gyrus may act as an endogenous repair mechanism in Alzheimer's disease (AD), and the Wnt signaling pathway has been suggested to closely modulate neurogenesis in amyloid-β (Aβ)-related AD models. The present study investigated whether mesenchymal stem cells (MSCs) would modulate hippocampal neurogenesis via modulation of the Wnt signaling pathway in a model of AD. In Aβ-treated neuronal progenitor cells (NPCs), the coculture with MSCs increased significantly the expression of Ki-67, GFAP, SOX2, nestin, and HuD compared to Aβ treatment alone. In addition, MSC treatment in Aβ-treated NPCs enhanced the expression of β-catenin and Ngn1 compared to Aβ treatment alone. MSC treatment in Aβ-treated animals significantly increased the number of BrdU-ir cells in the hippocampus at 2 and 4 weeks compared to Aβ treatment alone. In addition, quantitative analysis showed that the number of BrdU and HuD double-positive cells in the dentate gyrus was significantly higher in the MSC-treated group than in controls or after Aβ treatment alone. These results demonstrate that MSC administration significantly augments hippocampal neurogenesis and enhances the differentiation of NPCs into mature neurons in AD models by augmenting the Wnt signaling pathway. The use of MSCs to modulate endogenous adult neurogenesis may have a significant impact on future strategies for AD treatment.

  11. Electrocommunication signals alone are sufficient to increase neurogenesis in the brain of adult electric fish, Apteronotus leptorhynchus.

    PubMed

    Dunlap, Kent D; McCarthy, Elizabeth A; Jashari, Denisa

    2008-10-01

    Social interaction can have profound influences on the structure of the adult brain, but little is known about the precise stimulus feature found within social interaction that induces such brain plasticity. We examined the effects of social stimuli on cell addition and radial glial fiber formation in the brains of adult electric fish. These fish communicate primarily through weak, quasi-sinusoidal electric signals. Fish were housed in isolation, paired with another fish or exposed to only the electrocommunication signals of another fish for 7 days. After 3 days of exposure to these stimulus conditions, fish were injected with bromodeoxyuridine (BrdU) to mark newborn cells. We sacrificed the fish 4 days after BrdU injection and used immunohistochemistry to measure cell addition (BrdU+), the fraction of added cells that differentiated into neurons (BrdU+/NeuroTrace+) and the density of radial glia fibers (vimentin+) in the periventricular zone of the diencephalon. Fish that were exposed only to the electrocommunication signals of another fish and no other social stimuli had equivalent levels of cell addition and radial glial fiber density to fish that were housed with full social interaction and higher levels than fish housed in isolation. About 60% of the added cells differentiated into neurons; this fraction did not differ among treatment groups. Artificial sine wave electrical stimuli that mimicked electrocommunication signals were ineffective in increasing cell addition and glia fiber formation above those found in isolated fish. Thus, stimuli through a single modality are sufficient for inducing this brain plasticity, but the waveform or dynamic features of communication signals are crucial for the effect.

  12. The chemokine CXCL16 modulates neurotransmitter release in hippocampal CA1 area

    PubMed Central

    Di Castro, Maria Amalia; Trettel, Flavia; Milior, Giampaolo; Maggi, Laura; Ragozzino, Davide; Limatola, Cristina

    2016-01-01

    Chemokines have several physio-pathological roles in the brain. Among them, the modulation of synaptic contacts and neurotransmission recently emerged as crucial activities during brain development, in adulthood, upon neuroinflammation and neurodegenerative diseases. CXCL16 is a chemokine normally expressed in the brain, where it exerts neuroprotective activity against glutamate-induced damages through cross communication with astrocytes and the involvement of the adenosine receptor type 3 (A3R) and the chemokine CCL2. Here we demonstrated for the first time that CXCL16 exerts a modulatory activity on inhibitory and excitatory synaptic transmission in CA1 area. We found that CXCL16 increases the frequency of the miniature inhibitory synaptic currents (mIPSCs) and the paired-pulse ratio (PPR) of evoked IPSCs (eIPSCs), suggesting a presynaptic modulation of the probability of GABA release. In addition, CXCL16 increases the frequency of the miniature excitatory synaptic currents (mEPSCs) and reduces the PPR of evoked excitatory transmission, indicating that the chemokine also modulates and enhances the release of glutamate. These effects were not present in the A3RKO mice and in WT slices treated with minocycline, confirming the involvement of A3 receptors and introducing microglial cells as key mediators of the modulatory activity of CXCL16 on neurons. PMID:27721466

  13. Atypical chemokine receptor ACKR2 controls branching morphogenesis in the developing mammary gland.

    PubMed

    Wilson, Gillian J; Hewit, Kay D; Pallas, Kenneth J; Cairney, Claire J; Lee, Kit M; Hansell, Christopher A; Stein, Torsten; Graham, Gerard J

    2017-01-01

    Macrophages are important regulators of branching morphogenesis during development and postnatally in the mammary gland. Regulation of macrophage dynamics during these processes can therefore have a profound impact on development. We demonstrate here that the developing mammary gland expresses high levels of inflammatory CC-chemokines, which are essential in vivo regulators of macrophage migration. We further demonstrate that the atypical chemokine receptor ACKR2, which scavenges inflammatory CC-chemokines, is differentially expressed during mammary gland development. We have previously shown that ACKR2 regulates macrophage dynamics during lymphatic vessel development. Here, we extend these observations to reveal a novel role for ACKR2 in regulating the postnatal development of the mammary gland. Specifically, we show that Ackr2(-/-) mice display precocious mammary gland development. This is associated with increased macrophage recruitment to the developing gland and increased density of the ductal epithelial network. These data demonstrate that ACKR2 is an important regulator of branching morphogenesis in diverse biological contexts and provide the first evidence of a role for chemokines and their receptors in postnatal development processes.

  14. Chemokine receptor CCR5 and CXCR4 might influence virus replication during IBDV infection.

    PubMed

    Ou, Changbo; Wang, Qiuxia; Yu, Yan; Zhang, Yanhong; Ma, Jinyou; Kong, Xianghui; Liu, Xingyou

    2017-03-27

    Both CCR5 and CXCR4 are important chemokine receptors and take vital role in migration, development and distribution of T cells, however, whether they will influence the process of T cell infiltration into bursa of Fabricius during infectious bursal disease virus (IBDV) infection is unclear. In the current study, CCR5 and CXCR4 antagonists, Maraviroc and AMD3100, were administrated into chickens inoculated with IBDV, and the gene levels of IBDV VP2, CCR5, CXCR4 and related cytokines were determined by real-time PCR. The results showed that large number of T cells began to migrate into the bursae on Day 3 post infection with IBDV and the mRNA of chemokine receptors CCR5 and CXCR4 began to increase on Day 1. Moreover, antagonist treatments have increased the VP2, CCR5 and CXCR4 gene transcriptions and influenced on the gene levels of IL-2, IL-6, IL-8, IFN-γ, TGF-β4, MHC-I and MDA5. In conclusion, the chemokine receptors CCR5 and CXCR4 might influence virus replication during IBDV infection and further study would focus on the interaction between chemokine receptors and their ligands.

  15. Atypical chemokine receptor ACKR2 controls branching morphogenesis in the developing mammary gland

    PubMed Central

    Hewit, Kay D.; Pallas, Kenneth J.; Cairney, Claire J.; Lee, Kit M.; Hansell, Christopher A.; Stein, Torsten

    2017-01-01

    Macrophages are important regulators of branching morphogenesis during development and postnatally in the mammary gland. Regulation of macrophage dynamics during these processes can therefore have a profound impact on development. We demonstrate here that the developing mammary gland expresses high levels of inflammatory CC-chemokines, which are essential in vivo regulators of macrophage migration. We further demonstrate that the atypical chemokine receptor ACKR2, which scavenges inflammatory CC-chemokines, is differentially expressed during mammary gland development. We have previously shown that ACKR2 regulates macrophage dynamics during lymphatic vessel development. Here, we extend these observations to reveal a novel role for ACKR2 in regulating the postnatal development of the mammary gland. Specifically, we show that Ackr2−/− mice display precocious mammary gland development. This is associated with increased macrophage recruitment to the developing gland and increased density of the ductal epithelial network. These data demonstrate that ACKR2 is an important regulator of branching morphogenesis in diverse biological contexts and provide the first evidence of a role for chemokines and their receptors in postnatal development processes. PMID:27888192

  16. Complexin 3 Increases the Fidelity of Signaling in a Retinal Circuit by Regulating Exocytosis at Ribbon Synapses.

    PubMed

    Mortensen, Lena S; Park, Silvia J H; Ke, Jiang-Bin; Cooper, Benjamin H; Zhang, Lei; Imig, Cordelia; Löwel, Siegrid; Reim, Kerstin; Brose, Nils; Demb, Jonathan B; Rhee, Jeong-Seop; Singer, Joshua H

    2016-06-07

    Complexin (Cplx) proteins modulate the core SNARE complex to regulate exocytosis. To understand the contributions of Cplx to signaling in a well-characterized neural circuit, we investigated how Cplx3, a retina-specific paralog, shapes transmission at rod bipolar (RB)→AII amacrine cell synapses in the mouse retina. Knockout of Cplx3 strongly attenuated fast, phasic Ca(2+)-dependent transmission, dependent on local [Ca(2+)] nanodomains, but enhanced slower Ca(2+)-dependent transmission, dependent on global intraterminal [Ca(2+)] ([Ca(2+)]I). Surprisingly, coordinated multivesicular release persisted at Cplx3(-/-) synapses, although its onset was slowed. Light-dependent signaling at Cplx3(-/-) RB→AII synapses was sluggish, owing largely to increased asynchronous release at light offset. Consequently, propagation of RB output to retinal ganglion cells was suppressed dramatically. Our study links Cplx3 expression with synapse and circuit function in a specific retinal pathway and reveals a role for asynchronous release in circuit gain control.

  17. Expression of a Toll Signaling Regulator Serpin in a Mycoinsecticide for Increased Virulence

    PubMed Central

    Yang, Linzhi; Keyhani, Nemat O.; Tang, Guirong; Tian, Chuang; Lu, Ruipeng; Wang, Xin; Pei, Yan

    2014-01-01

    Serpins are ubiquitously distributed serine protease inhibitors that covalently bind to target proteases to exert their activities. Serpins regulate a wide range of activities, particularly those in which protease-mediated cascades are active. The Drosophila melanogaster serpin Spn43Ac negatively controls the Toll pathway that is activated in response to fungal infection. The entomopathogenic fungus Beauveria bassiana offers an environmentally friendly alternative to chemical pesticides for insect control. However, the use of mycoinsecticides remains limited in part due to issues of efficacy (low virulence) and the recalcitrance of the targets (due to strong immune responses). Since Spn43Ac acts to inhibit Toll-mediated activation of defense responses, we explored the feasibility of a new strategy to engineer entomopathogenic fungi with increased virulence by expression of Spn43Ac in the fungus. Compared to the 50% lethal dose (LD50) for the wild-type parent, the LD50 of B. bassiana expressing Spn43Ac (strain Bb::S43Ac-1) was reduced ∼3-fold, and the median lethal time against the greater wax moth (Galleria mellonella) was decreased by ∼24%, with the more rapid proliferation of hyphal bodies being seen in the host hemolymph. In vitro and in vivo assays showed inhibition of phenoloxidase (PO) activation in the presence of Spn43Ac, with Spn43Ac-mediated suppression of activation by chymotrypsin, trypsin, laminarin, and lipopolysaccharide occurring in the following order: chymotrypsin and trypsin > laminarin > lipopolysaccharide. Expression of Spn43Ac had no effect on the activity of the endogenous B. bassiana-derived cuticle-degrading protease (CDEP-1). These results expand our understanding of Spn43Ac function and confirm that suppression of insect immune system defenses represents a feasible approach to engineering entomopathogenic fungi for greater efficacy. PMID:24837378

  18. The absence of VGLUT3 predisposes to cocaine abuse by increasing dopamine and glutamate signaling in the nucleus accumbens.

    PubMed

    Sakae, D Y; Marti, F; Lecca, S; Vorspan, F; Martín-García, E; Morel, L J; Henrion, A; Gutiérrez-Cuesta, J; Besnard, A; Heck, N; Herzog, E; Bolte, S; Prado, V F; Prado, M A M; Bellivier, F; Eap, C B; Crettol, S; Vanhoutte, P; Caboche, J; Gratton, A; Moquin, L; Giros, B; Maldonado, R; Daumas, S; Mameli, M; Jamain, S; El Mestikawy, S

    2015-11-01

    Tonically active cholinergic interneurons (TANs) from the nucleus accumbens (NAc) are centrally involved in reward behavior. TANs express a vesicular glutamate transporter referred to as VGLUT3 and thus use both acetylcholine and glutamate as neurotransmitters. The respective roles of each transmitter in the regulation of reward and addiction are still unknown. In this study, we showed that disruption of the gene that encodes VGLUT3 (Slc17a8) markedly increased cocaine self-administration in mice. Concomitantly, the amount of dopamine (DA) release was strongly augmented in the NAc of VGLUT3(-/-) mice because of a lack of signaling by metabotropic glutamate receptors. Furthermore, dendritic spines and glutamatergic synaptic transmission on medium spiny neurons were increased in the NAc of VGLUT3(-/-) mice. Increased DA and glutamate signaling in the NAc are hallmarks of addiction. Our study shows that TANs use glutamate to reduce DA release and decrease reinforcing properties of cocaine in mice. Interestingly, we also observed an increased frequency of rare variations in SLC17A8 in a cohort of severe drug abusers compared with controls. Our findings identify VGLUT3 as an unexpected regulator of drug abuse.

  19. Floral colour signal increases short-range detectability of a sexually deceptive orchid to its bee pollinator.

    PubMed

    Streinzer, Martin; Paulus, Hannes F; Spaethe, Johannes

    2009-05-01

    Orchids of the genus Ophrys are pollinated by males of solitary bees and wasps through sexual deception. The flowers mimic the behaviourally active compounds of the sex pheromone of receptive females and thus attract males that seek to copulate. Odour is the main attractant while visual stimuli have been assumed so far to play only a minor role. In contrast to most species of the genus, Heldreich's orchid Ophrys heldreichii, which is pollinated by males of the long-horned bee Tetralonia berlandi, possesses a bright pink perianth that appears conspicuous to a human observer. We investigated the role of this floral colour signal in pollinator attraction. We filmed approach flights of male bees to flowers in which we removed the original perianth and in which we substituted the perianth with an artificial one of a particular selected colour. At distances >30 cm, male search time correlated only with wind speed but not with the spectral parameters of the perianth, i.e. chromatic and green receptor-specific contrast. By contrast, in the close range (<30 cm), where the perianth subtends a visual angle of at least 5 deg. to the bee's eye, search time decreased with increasing green receptor contrast between perianth and background; however, no correlation with chromatic contrast or wind speed was found. Our results indicate that pollinators are first attracted by olfactory signals from a distance. Once in the vicinity of the flower where spatial vision of the males is sufficient, they are guided exclusively by vision. However, it can be expected that possession of a ;non-private' colour signal would increase the risk of pollen loss in sexually deceptive orchids by accidentally attracting non-specific flower visitors. We therefore discuss the occurrence of colour signals in the genus Ophrys in respect to the species-specific visual system of the pollinators.

  20. Deconvolution analyses with tent functions reveal delayed and long-sustained increases of BOLD signals with acupuncture stimulation.

    PubMed

    Murase, Tomokazu; Umeda, Masahiro; Fukunaga, Masaki; Tanaka, Chuzo; Higuchi, Toshihiro

    2013-01-01

    We used deconvolution analysis to examine temporal changes in brain activity after acupuncture stimulation and assess brain responses without expected reference functions. We also examined temporal changes in brain activity after sham acupuncture (noninsertive) and scrubbing stimulation. We divided 26 healthy right-handed adults into a group of 13 who received real acupuncture with manual manipulation and a group of 13 who received both tactical stimulations. Functional magnetic resonance imaging (fMRI) sequences consisted of four 15-s stimulation blocks (ON) interspersed between one 30-s and four 45-s rest blocks (OFF) for a total scanning time of 270 s. We analyzed data by using Statistical Parametric Mapping 8 (SPM8), MarsBaR, and Analysis of Functional NeuroImages (AFNI) software. For statistical analysis, we used 3dDeconvolve, part of the AFNI package, to extract the impulse response functions (IRFs) of the fMRI signals on a voxel-wise basis, and we tested the time courses of the extracted IRFs for the stimulations. We found stimulus-specific impulse responses of blood oxygen level-dependent (BOLD) signals in various brain regions. We observed significantly delayed and long-sustained increases of BOLD signals in several brain regions following real acupuncture compared to sham acupuncture and palm scrubbing, which we attribute to peripheral nocireceptors, flare responses, and processing of the central nervous system. Acupuncture stimulation induced continued activity that was stronger than activity after the other stimulations. We used tent function deconvolution to process fMRI data for acupuncture stimulation and found delayed increasing and delayed decreasing changes in BOLD signal in the somatosensory areas and areas related to pain perception. Deconvolution analyses with tent functions are expected to be useful in extracting complicated and associated brain activity that is delayed and sustained for a long period after various stimulations.

  1. Adenosine Signaling Increases Proinflammatory and Profibrotic Mediators through Activation of a Functional Adenosine 2B Receptor in Renal Fibroblasts.

    PubMed

    Wilkinson, Patrick F; Farrell, Francis X; Morel, Diane; Law, William; Murphy, Suzanne

    2016-07-01

    Interstitial renal fibrosis is a major pathophysiological manifestation of patients diagnosed with Chronic Kidney Disease (CKD), Diabetic Nephropathy (DN) and other inflammatory diseases. Adenosine signaling is an innate autocrine and paracrine cellular signaling pathway involving several key mediators that are elevated in the blood and kidneys of patients with DN. In these studies, we hypothesized that extracellular adenosine signals through one or more functional adenosine GPCRs on renal fibroblasts which increases profibrotic and proinflammatory mediators by inducing an activated fibroblast phenotype. Utilizing the renal fibroblast cell line NRK-49F, the presence and relative abundance of adenosine receptors (AR) A1, A2A, A2B, and A3 were quantified by RT-PCR. Under normal homeostatic conditions, only AR1 and AR2B were detected. The functionality of each receptor was then assessed by receptor specific pharmacological agonism and antagonism and assessed for modulation of the GPCR associated secondary messenger molecule, cyclic adenosine monophosphate (cAMP). Agonism of the AR2B receptor resulted in increased intracellular cAMP while agonism of the AR1 receptor inhibited cAMP modulation. Upon direct agonism of the AR2B receptor, transcripts for profibrotic and inflammatory mediators including SMA-α, IL-6, TGF-β, CTGF, and fibronectin were elevated between 2-4 fold. These data indicate that renal fibroblasts express a functional AR1 receptor that inhibits cAMP upon stimulation, leading to a functional AR2B receptor that increases cAMP upon stimulation and also induces an activated fibroblast phenotype resulting in increased fibrotic and inflammatory mediators.

  2. Knockdown of GSK3β increases basal autophagy and AMPK signalling in nutrient-laden human aortic endothelial cells

    PubMed Central

    Weikel, Karen A.; Cacicedo, José M.; Ruderman, Neil B.; Ido, Yasuo

    2016-01-01

    High concentrations of glucose and palmitate increase endothelial cell inflammation and apoptosis, events that often precede atherogenesis. They may do so by decreasing basal autophagy and AMP-activated protein kinase (AMPK) activity, although the mechanisms by which this occurs are not clear. Decreased function of the lysosome, an organelle required for autophagy and AMPK, have been associated with hyperactivity of glycogen synthase kinase 3β (GSK3β). To determine whether GSK3β affects nutrient-induced changes in autophagy and AMPK activity, we used a primary human aortic endothelial cell (HAEC) model of type 2 diabetes that we had previously characterized with impaired AMPK activity and autophagy [Weikel et al. (2015) Am. J. Phys. Cell Physiol. 308, C249–C263]. Presently, we found that incubation of HAECs with excess nutrients (25 mM glucose and 0.4 mM palmitate) increased GSK3β activity and impaired lysosome acidification. Suppression of GSK3β in these cells by treatment with a chemical inhibitor or overexpression of kinase-dead GSK3β attenuated these lysosomal changes. Under control and excess nutrient conditions, knockdown of GSK3β increased autophagosome formation, forkhead box protein O1 (FOXO1) activity and AMPK signalling and decreased Akt signalling. Similar changes in autophagy, AMPK and Akt signalling were observed in aortas from mice treated with the GSK3β inhibitor CHIR 99021. Thus, increasing basal autophagy and AMPK activity by inhibiting GSK3β may be an effective strategy in the setting of hyperglycaemia and dyslipidaemia for restoring endothelial cell health and reducing atherogenesis. PMID:27534430

  3. Absence of Suppressor of Cytokine Signaling-2 turns cardiomyocytes unresponsive to LIF-dependent increase in Ca2+ levels.

    PubMed

    Rocha-Resende, Cibele; Jesus, Itamar Couto Guedes de; Roman-Campos, Danilo; Miranda, Artur S; Alves, Fabiana; Resende, Rodrigo Ribeiro; Cruz, Jader Dos Santos; Machado, Fabiana Simão; Guatimosim, Silvia

    2017-01-25

    Little is known regarding the role of the Suppressor of Cytokine Signaling (SOCS) in the control of cytokine signaling in cardiomyocytes. We investigated the consequences of SOCS2 ablation for Leukemia Inhibitory Factor (LIF)-induced enhancement of intracellular Ca(2+) ([Ca(2+)]i) transient by performing experiments with cardiomyocytes from SOCS2-knockout (ko) mice. Similar levels of SOCS3 transcripts were seen in cardiomyocytes from wild-type and SOCS2-ko, while SOCS1 mRNA was reduced in SOCS2-ko. Immunoprecipitation experiments showed increased SOCS3 association with gp130 receptor in SOCS2-ko myocytes. Measurements of Ca(2+) in wild-type myocytes exposed to LIF showed a significant increase in the magnitude of the Ca(2+) transient. These changes were absent in LIF-treated SOCS2-ko cells. LIF activation of ERK and STAT3 was observed in both wild-type and SOCS2-ko cells, indicating that in SOCS2-ko LIF receptors were functional, despite the lack of effect in the Ca(2+) transient. In wild-type cells, LIF-induced increase in [Ca(2+)]i and phospholamban (PLN)(Thr17) phosphorylation was inhibited by KN93, indicating a role for CaMKII in LIF-induced Ca(2+) raise. LIF-induced phosphorylation of PLN(Thr17) was abrogated in SOCS2-ko myocytes. In wild-type cardiomyocytes, LIF treatment increased L-type Ca(2+) current (ICa,L), a key activator of CaMKII in response to LIF. Conversely, SOCS2-ko myocytes failed to activate ICa,L in response to LIF, providing a rational for the lack of LIF effect on Ca(2+) transient. Our data show that absence of SOCS2 turns cardiomyocytes unresponsive to LIF-induced [Ca(2+)] raise, indicating that endogenous levels of SOCS2 are crucial for full activation of LIF signaling in the heart.

  4. Knockdown of GSK3β increases basal autophagy and AMPK signalling in nutrient-laden human aortic endothelial cells.

    PubMed

    Weikel, Karen A; Cacicedo, José M; Ruderman, Neil B; Ido, Yasuo

    2016-10-01

    High concentrations of glucose and palmitate increase endothelial cell inflammation and apoptosis, events that often precede atherogenesis. They may do so by decreasing basal autophagy and AMP-activated protein kinase (AMPK) activity, although the mechanisms by which this occurs are not clear. Decreased function of the lysosome, an organelle required for autophagy and AMPK, have been associated with hyperactivity of glycogen synthase kinase 3β (GSK3β). To determine whether GSK3β affects nutrient-induced changes in autophagy and AMPK activity, we used a primary human aortic endothelial cell (HAEC) model of type 2 diabetes that we had previously characterized with impaired AMPK activity and autophagy [Weikel et al. (2015) Am. J. Phys. Cell Physiol. 308: , C249-C263]. Presently, we found that incubation of HAECs with excess nutrients (25 mM glucose and 0.4 mM palmitate) increased GSK3β activity and impaired lysosome acidification. Suppression of GSK3β in these cells by treatment with a chemical inhibitor or overexpression of kinase-dead GSK3β attenuated these lysosomal changes. Under control and excess nutrient conditions, knockdown of GSK3β increased autophagosome formation, forkhead box protein O1 (FOXO1) activity and AMPK signalling and decreased Akt signalling. Similar changes in autophagy, AMPK and Akt signalling were observed in aortas from mice treated with the GSK3β inhibitor CHIR 99021. Thus, increasing basal autophagy and AMPK activity by inhibiting GSK3β may be an effective strategy in the setting of hyperglycaemia and dyslipidaemia for restoring endothelial cell health and reducing atherogenesis.

  5. Palmitate increases musclin gene expression through activation of PERK signaling pathway in C2C12 myotubes.

    PubMed

    Gu, Ning; Guo, Qian; Mao, Ke; Hu, Hailong; Jin, Sanli; Zhou, Ying; He, Hongjuan; Oh, Yuri; Liu, Chuanpeng; Wu, Qiong

    2015-11-20

    Musclin is a type of muscle-secreted cytokine and its increased gene expression induces insulin resistance in type 2 diabetes. However, the mechanism underlying increased musclin gene expression is currently unclear. Excessive saturated fatty acids (SFA) can activate the secretion of several muscle-secreted cytokines as well as endoplasmic reticulum (ER) stress pathway, thereby contributing to the development of type 2 diabetes. The purpose of this study was to investigate the mechanisms responsible for the effect of palmitate, the most abundant SFA in the plasma, on the gene expression of musclin in C2C12 myotubes. Treatment of C2C12 myotubes with palmitate or tunicamycin significantly increased the expression of musclin as well as ER stress-related genes, but treatment with oleate did not. Pre-treatment of C2C12 myotubes with 4-phenyl butyrate suppressed the expression of ER stress-related genes, simultaneously, resulting in decreased expression of the musclin gene induced by palmitate or tunicamycin. These results indicate that ER stress is related to palmitate-induced musclin gene expression. Moreover, palmitate-induced musclin gene expression was significantly inhibited in C2C12 myotubes when PERK pathway signaling was suppressed by knockdown of the PERK gene or treatment with GSK2656157, a PERK autophosphorylation inhibitor. However, there was no difference in the palmitate-induced musclin gene expression when IRE1 and ATF6 signaling pathways were suppressed by knockdown of the IRE1 and ATF6 genes. These findings suggest that palmitate increases musclin gene expression via the activation of the PERK signaling pathway in C2C12 myotubes.

  6. Cutting edge: JAM-C controls homeostatic chemokine secretion in lymph node fibroblastic reticular cells expressing thrombomodulin.

    PubMed

    Frontera, Vincent; Arcangeli, Marie-Laure; Zimmerli, Claudia; Bardin, Florence; Obrados, Elodie; Audebert, Stéphane; Bajenoff, Marc; Borg, Jean-Paul; Aurrand-Lions, Michel

    2011-07-15

    The development and maintenance of secondary lymphoid organs, such as lymph nodes, occur in a highly coordinated manner involving lymphoid chemokine production by stromal cells. Although developmental pathways inducing lymphoid chemokine production during organogenesis are known, signals maintaining cytokine production in adults are still elusive. In this study, we show that thrombomodulin and platelet-derived growth factor receptor α identify a population of fibroblastic reticular cells in which chemokine secretion is controlled by JAM-C. We demonstrate that Jam-C-deficient mice and mice treated with Ab against JAM-C present significant decreases in stromal cell-derived factor 1α (CXCL12), CCL21, and CCL19 intranodal content. This effect is correlated with reduced naive T cell egress from lymph nodes of anti-JAM-C-treated mice.

  7. Chemokines and relapses in childhood acute lymphoblastic leukemia: A role in migration and in resistance to antileukemic drugs.

    PubMed

    Gómez, Ana M; Martínez, Carolina; González, Miguel; Luque, Alfonso; Melen, Gustavo J; Martínez, Jesús; Hortelano, Sonsoles; Lassaletta, Álvaro; Madero, Luís; Ramírez, Manuel

    2015-10-01

    We studied whether chemokines may have a role in relapses in childhood acute lymphoblastic leukemia (ALL). We compared the levels of chemokine receptors in marrow samples from 82 children with ALL at diagnosis versus 15 at relapses, and quantified the levels of chemokines in central system fluid (CSF) samples. The functional role of specific chemokines was studied in vitro and in vivo. The expression of some chemokine receptors was upregulated upon leukemic relapse, both in B- and in T-ALL, and in cases of medullary and extramedullary involvement. CXCL10 induced chemotaxis in leukemic cell lines and in primary leukemic cells, depending upon the levels of CXCR3 expression. CXCL10 specifically diminished chemotherapy-induced apoptosis on ALL cells expressing CXCR3, partially inhibiting caspase activation and maintaining the levels of the antiapoptotic protein Bcl-2. Finally, immunodeficient mice engrafted with CXCR3-expressing human leukemic cells showed decreased infiltration of marrow, spleen, and CNS after receiving a CXCR3-antagonist molecule. CXCR3 signaling in ALL may have a dual function: chemotactic for the localisation of leukemic blasts in specific niches, and it may also confer resistance to chemotherapy, enhancing the chances for relapses.

  8. Multiple roles of chemokine CXCL12 in the central nervous system: A migration from immunology to neurobiology

    PubMed Central

    Li, Meizhang; Ransohoff, Richard M.

    2008-01-01

    Chemotactic cytokines (chemokines) have been traditionally defined as small (10–14 kDa) secreted leukocyte chemoattractants. However, chemokines and their cognate receptors are constitutively expressed in the central nervous system (CNS) where immune activities are under stringent control. Why and how the CNS uses the chemokine system to carry out its complex physiological functions has intrigued neurobiologists. Here, we focus on chemokine CXCL12 and its receptor CXCR4 that have been widely characterized in peripheral tissues and delineate their main functions in the CNS. Extensive evidence supports CXCL12 as a key regulator for early development of the CNS. CXCR4 signaling is required for the migration of neuronal precursors, axon guidance/pathfinding and maintenance of neural progenitor cells (NPCs). In the mature CNS, CXCL12 modulates neurotransmission, neurotoxicity and neuroglial interactions. Thus, chemokines represent an inherent system that helps establish and maintain CNS homeostasis. In addition, growing evidence implicates altered expression of CXCL12 and CXCR4 in the pathogenesis of CNS disorders such as HIV-associated encephalopathy, brain tumor, stroke and multiple sclerosis (MS), making them the plausible targets for future pharmacological intervention. PMID:18177992

  9. Structure of mouse IP-10, a chemokine

    SciTech Connect

    Jabeen, Talat; Leonard, Philip; Jamaluddin, Haryati; Acharya, K. Ravi

    2008-06-01

    The structure of mouse IP-10 shows a novel tetrameric association. Interferon-γ-inducible protein (IP-10) belongs to the CXC class of chemokines and plays a significant role in the pathophysiology of various immune and inflammatory responses. It is also a potent angiostatic factor with antifibrotic properties. The biological activities of IP-10 are exerted by interactions with the G-protein-coupled receptor CXCR3 expressed on Th1 lymphocytes. IP-10 thus forms an attractive target for structure-based rational drug design of anti-inflammatory molecules. The crystal structure of mouse IP-10 has been determined and reveals a novel tetrameric association. In the tetramer, two conventional CXC chemokine dimers are associated through their N-terminal regions to form a 12-stranded elongated β-sheet of ∼90 Å in length. This association differs significantly from the previously studied tetramers of human IP-10, platelet factor 4 and neutrophil-activating peptide-2. In addition, heparin- and receptor-binding residues were mapped on the surface of IP-10 tetramer. Two heparin-binding sites were observed on the surface and were present at the interface of each of the two β-sheet dimers. The structure supports the formation of higher order oligomers of IP-10, as observed in recent in vivo studies with mouse IP-10, which will have functional relevance.

  10. The chemokine receptor CXCR4 promotes granuloma formation by sustaining a mycobacteria-induced angiogenesis programme

    PubMed Central

    Torraca, Vincenzo; Tulotta, Claudia; Snaar-Jagalska, B. Ewa; Meijer, Annemarie H.

    2017-01-01

    CXC chemokine receptor 4 plays a critical role in chemotaxis and leukocyte differentiation. Furthermore, there is increasing evidence that links this receptor to angiogenesis. Using the well-established zebrafish-Mycobacterium marinum model for tuberculosis, angiogenesis was recently found to be important for the development of cellular aggregates called granulomas that contain the mycobacteria and are the hallmark of tuberculosis disease. Here, we found that initiation of the granuloma-associated proangiogenic programme requires CXCR4 signalling. The nascent granulomas in cxcr4b-deficient zebrafish embryos were poorly vascularised, which in turn also delayed bacterial growth. Suppressed infection expansion in cxcr4b mutants could not be attributed to an overall deficient recruitment of leukocytes or to different intramacrophage bacterial growth rate, as cxcr4b mutants displayed similar microbicidal capabilities against initial mycobacterial infection and the cellular composition of granulomatous lesions was similar to wildtype siblings. Expression of vegfaa was upregulated to a similar extent in cxcr4b mutants and wildtypes, suggesting that the granuloma vascularisation phenotype of cxcr4b mutants is independent of vascular endothelial growth factor. PMID:28332618

  11. Increasing effect of Tangzhiqing formula on IRS-1-dependent PI3K/AKT signaling in muscle

    PubMed Central

    2014-01-01

    Background Tangzhiqing fomula (TZQ-F), the mixture of Red Paeony root, Mulberry leaf, Lotus leaf, Danshen root and Hawthorn leaf, regulates the abnormal glucose and lipids in prediabetic patients. In this study, we focus on the mechanism of TZQ-F and its fractions on glucose metabolism. Methods After orally administration of TZQ-F for 4 weeks in KK-Ay mice, we dissected out the liver and muscle, and employed PCR and western blotting to screening the PI3K/AKT pathway. The following PI3K/AKT signaling pathway were performed in L-6 myotube and HepG2 cells. Results In the liver of KK-Ay mice, no significance was observed on PI3K, AKT and their phosphorylation between TZQ-F and controls , while, in the muscle, up-regulation of PI3K, AKT, Glycogen synthase (GYS) and their phosphorylation type, as well as GluT4, was deteced in TZQ-F. In HepG2 cells, TZQ-F increased IRS-2 by 10 folds, without interrupting AKT, IRS-1 and GluT4. In L-6 myotube cells, TZQ-F and its fractions treatment significantly increased IRS-1 and AKT at mRNA level. Conclusion TZQ-F prevents pre-diabetes through increasing effect on IRS-1-dependent PI3K/AKT signaling pathway in muscle. PMID:24952587

  12. Lonchocarpine Increases Nrf2/ARE-Mediated Antioxidant Enzyme Expression by Modulating AMPK and MAPK Signaling in Brain Astrocytes

    PubMed Central

    Jeong, Yeon-Hui; Park, Jin-Sun; Kim, Dong-Hyun; Kim, Hee-Sun

    2016-01-01

    Lonchocarpine is a phenylpropanoid compound isolated from Abrus precatorius that has anti-bacterial, anti-inflammatory, antiproliferative, and antiepileptic activities. In the present study, we investigated the antioxidant effects of lonchocarpine in brain glial cells and analyzed its molecular mechanisms. We found that lonchocarpine suppressed reactive oxygen species (ROS) production and cell death in hydrogen peroxide-treated primary astrocytes. In addition, lonchocarpine increased the expression of antioxidant enzymes, such as heme oxygenase-1 (HO-1), NAD(P)H:quinone oxidoreductase 1 (NQO1), and manganese superoxide dismutase (MnSOD), which are all under the control of Nrf2/antioxidant response element (ARE) signaling. Further, mechanistic studies showed that lonchocarpine increases the nuclear translocation and DNA binding of Nrf2 to ARE as well as ARE-mediated transcriptional activities. Moreover, lonchocarpine increased the phosphorylation of AMP-activated protein kinase (AMPK) and three types of mitogen-activated protein kinases (MAPKs). By treating astrocytes with each signaling pathway-specific inhibitor, AMPK, c-jun N-terminal protein kinase (JNK), and p38 MAPK were identified to be involved in lonchocarpine-induced HO-1 expression and ARE-mediated transcriptional activities. Therefore, lonchocarpine may be a potential therapeutic agent for neurodegenerative diseases that are associated with oxidative stress. PMID:27737527

  13. Constitutive TLR4 signalling in intestinal epithelium reduces tumor load by increasing apoptosis in APC(Min/+) mice.

    PubMed

    Li, Y; Teo, W L; Low, M J; Meijer, L; Sanderson, I; Pettersson, S; Greicius, G

    2014-01-16

    The microbial pattern-recognizing Toll-like receptors (TLRs) are major signal transducers known to shape and influence the postnatal maturation of host intestinal epithelium. Perturbations in this intricate host-microbe cross-talk have been reported to be associated with uncontrolled epithelial cell growth and thus potential cancer development by mechanisms which are largely unknown. We therefore generated transgenic mice carrying a constitutively active TLR4 (CD4-TLR4) linked to an intestinal epithelial cell-specific promoter. Ex vivo analysis of transgenic crypt-villus organoid cultures revealed an increased proliferative capacity and a lowered cyclooxygenase 2 (Cox-2) expression in these organoids compared with wild-type control cultures. Introducing the CD4-TLR4 transgene into APC(Min/+) mice (CD4-TLR4-APC(Min/+)), a model of colorectal carcinoma, resulted in a dramatic drop in tumor load as compared with control APC(Min/+) mice. Intestinal tumors from CD4-TLR4-APC(Min/+) mice displayed reduced Cox-2 protein, elevated interferon β expression and increased caspase-3 activity, which correlated with increased apoptosis in vivo. Thus, our data reveal that host microbiota-mediated signal transduction via TLR4 in intestinal epithelial cells is far more complex than what is previously reported.

  14. Viral mimicry of cytokines, chemokines and their receptors.

    PubMed

    Alcami, Antonio

    2003-01-01

    Viruses have evolved elegant mechanisms to evade detection and destruction by the host immune system. One of the evasion strategies that have been adopted by large DNA viruses is to encode homologues of cytokines, chemokines and their receptors--molecules that have a crucial role in control of the immune response. Viruses have captured host genes or evolved genes to target specific immune pathways, and so viral genomes can be regarded as repositories of important information about immune processes, offering us a viral view of the host immune system. The study of viral immunomodulatory proteins might help us to uncover new human genes that control immunity, and their characterization will increase our understanding of not only viral pathogenesis, but also normal immune mechanisms. Moreover, viral proteins indicate strategies of immune modulation that might have therapeutic potential.

  15. Prenatal ethanol exposure increases osteoarthritis susceptibility in female rat offspring by programming a low-functioning IGF-1 signaling pathway.

    PubMed

    Ni, Qubo; Tan, Yang; Zhang, Xianrong; Luo, Hanwen; Deng, Yu; Magdalou, Jacques; Chen, Liaobin; Wang, Hui

    2015-10-05

    Epidemiological evidence indicates that osteoarthritis (OA) and prenatal ethanol exposure (PEE) are both associated with low birth weight but possible causal interrelationships have not been investigated. To investigate the effects of PEE on the susceptibility to OA in adult rats that experienced intrauterine growth retardation (IUGR), and to explore potential intrauterine mechanisms, we established the rat model of IUGR by PEE and dexamethasone, and the female fetus and 24-week-old adult offspring subjected to strenuous running for 6 weeks were sacrificed. Knee joints were collected from fetuses and adult offspring for histochemistry, immunohistochemistry and qPCR assays. Histological analyses and the Mankin score revealed increased cartilage destruction and accelerated OA progression in adult offspring from the PEE group compared to the control group. Immunohistochemistry showed reduced expression of insulin-like growth factor-1 (IGF-1) signaling pathway components. Furthermore, fetuses in the PEE group experienced IUGR but exhibited a higher postnatal growth rate. The expression of many IGF-1 signaling components was downregulated, which coincided with reduced amounts of type II collagen in the epiphyseal cartilage of fetuses in the PEE group. These results suggest that PEE enhances the susceptibility to OA in female adult rat offspring by down-regulating IGF-1 signaling and retarding articular cartilage development.

  16. The art of braking: Post saccadic oscillations in the eye tracker signal decrease with increasing saccade size.

    PubMed

    Hooge, Ignace; Nyström, Marcus; Cornelissen, Tim; Holmqvist, Kenneth

    2015-07-01

    Recent research has shown that the pupil signal from video-based eye trackers contains post saccadic oscillations (PSOs). These reflect pupil motion relative to the limbus (Nyström, Hooge, & Holmqvist, 2013). More knowledge about video-based eye tracker signals is essential to allow comparison between the findings obtained from modern systems, and those of older eye tracking technologies (e.g. coils and measurement of the Dual Purkinje Image-DPI). We investigated PSOs in horizontal and vertical saccades of different sizes with two high quality video eye trackers. PSOs were very similar within observers, but not between observers. PSO amplitude decreased with increasing saccade size, and this effect was even stronger in vertical saccades; PSOs were almost absent in large vertical saccades. Based on this observation we conclude that the occurrence of PSOs is related to deceleration at the end of a saccade. That PSOs are saccade size dependent and idiosyncratic is a problem for algorithmic determination of saccade endings. Careful description of the eye tracker, its signal, and the procedure used to extract saccades is required to enable researchers to compare data from different eye trackers.

  17. Prenatal ethanol exposure increases osteoarthritis susceptibility in female rat offspring by programming a low-functioning IGF-1 signaling pathway

    NASA Astrophysics Data System (ADS)

    Ni, Qubo; Tan, Yang; Zhang, Xianrong; Luo, Hanwen; Deng, Yu; Magdalou, Jacques; Chen, Liaobin; Wang, Hui

    2015-10-01

    Epidemiological evidence indicates that osteoarthritis (OA) and prenatal ethanol exposure (PEE) are both associated with low birth weight but possible causal interrelationships have not been investigated. To investigate the effects of PEE on the susceptibility to OA in adult rats that experienced intrauterine growth retardation (IUGR), and to explore potential intrauterine mechanisms, we established the rat model of IUGR by PEE and dexamethasone, and the female fetus and 24-week-old adult offspring subjected to strenuous running for 6 weeks were sacrificed. Knee joints were collected from fetuses and adult offspring for histochemistry, immunohistochemistry and qPCR assays. Histological analyses and the Mankin score revealed increased cartilage destruction and accelerated OA progression in adult offspring from the PEE group compared to the control group. Immunohistochemistry showed reduced expression of insulin-like growth factor-1 (IGF-1) signaling pathway components. Furthermore, fetuses in the PEE group experienced IUGR but exhibited a higher postnatal growth rate. The expression of many IGF-1 signaling components was downregulated, which coincided with reduced amounts of type II collagen in the epiphyseal cartilage of fetuses in the PEE group. These results suggest that PEE enhances the susceptibility to OA in female adult rat offspring by down-regulating IGF-1 signaling and retarding articular cartilage development.

  18. Prenatal ethanol exposure increases osteoarthritis susceptibility in female rat offspring by programming a low-functioning IGF-1 signaling pathway

    PubMed Central

    Ni, Qubo; Tan, Yang; Zhang, Xianrong; Luo, Hanwen; Deng, Yu; Magdalou, Jacques; Chen, Liaobin; Wang, Hui

    2015-01-01

    Epidemiological evidence indicates that osteoarthritis (OA) and prenatal ethanol exposure (PEE) are both associated with low birth weight but possible causal interrelationships have not been investigated. To investigate the effects of PEE on the susceptibility to OA in adult rats that experienced intrauterine growth retardation (IUGR), and to explore potential intrauterine mechanisms, we established the rat model of IUGR by PEE and dexamethasone, and the female fetus and 24-week-old adult offspring subjected to strenuous running for 6 weeks were sacrificed. Knee joints were collected from fetuses and adult offspring for histochemistry, immunohistochemistry and qPCR assays. Histological analyses and the Mankin score revealed increased cartilage destruction and accelerated OA progression in adult offspring from the PEE group compared to the control group. Immunohistochemistry showed reduced expression of insulin-like growth factor-1 (IGF-1) signaling pathway components. Furthermore, fetuses in the PEE group experienced IUGR but exhibited a higher postnatal growth rate. The expression of many IGF-1 signaling components was downregulated, which coincided with reduced amounts of type II collagen in the epiphyseal cartilage of fetuses in the PEE group. These results suggest that PEE enhances the susceptibility to OA in female adult rat offspring by down-regulating IGF-1 signaling and retarding articular cartilage development. PMID:26434683

  19. Dynamic filopodia are required for chemokine-dependent intracellular polarization during guided cell migration in vivo.

    PubMed

    Meyen, Dana; Tarbashevich, Katsiaryna; Banisch, Torsten U; Wittwer, Carolina; Reichman-Fried, Michal; Maugis, Benoît; Grimaldi, Cecilia; Messerschmidt, Esther-Maria; Raz, Erez

    2015-04-15

    Cell migration and polarization is controlled by signals in the environment. Migrating cells typically form filopodia that extend from the cell surface, but the precise function of these structures in cell polarization and guided migration is poorly understood. Using the in vivo model of zebrafish primordial germ cells for studying chemokine-directed single cell migration, we show that filopodia distribution and their dynamics are dictated by the gradient of the chemokine Cxcl12a. By specifically interfering with filopodia formation, we demonstrate for the first time that these protrusions play an important role in cell polarization by Cxcl12a, as manifested by elevation of intracellular pH and Rac1 activity at the cell front. The establishment of this polarity is at the basis of effective cell migration towards the target. Together, we show that filopodia allow the interpretation of the chemotactic gradient in vivo by directing single-cell polarization in response to the guidance cue.

  20. The Role of CC-Chemokines in the Regulation of Angiogenesis

    PubMed Central

    Ridiandries, Anisyah; Tan, Joanne T. M.; Bursill, Christina A.

    2016-01-01

    Angiogenesis, the formation of new blood vessels, is critical for survival and in the regenerative response to tissue injury or ischemia. However, in diseases such as cancer and atherosclerosis, inflammation can cause unregulated angiogenesis leading to excessive neovascularization, which exacerbates disease. Current anti-angiogenic therapies cause complete inhibition of both inflammatory and ischemia driven angiogenesis causing a range of side effects in patients. Specific inhibition of inflammation-driven angiogenesis would therefore be immensely valuable. Increasing evidence suggests that the CC-chemokine class promotes inflammation-driven angiogenesis, whilst there is little evidence for a role in ischemia-mediated angiogenesis. The differential regulation of angiogenesis by CC-chemokines suggests it may provide an alternate strategy to treat angiogenesis associated pathological diseases. The focus of this review is to highlight the significant role of the CC-chemokine class in inflammation, versus ischemia driven angiogenesis, and to discuss the related pathologies including atherosclerosis, cancer, and rheumatoid arthritis. We examine the pros and cons of anti-angiogenic therapies currently in clinical trials. We also reveal novel therapeutic strategies that cause broad-spectrum inhibition of the CC-chemokine class that may have future potential for the specific inhibition of inflammatory angiogenesis. PMID:27834814

  1. Use of propidium monoazide and increased amplicon length reduce false-positive signals in quantitative PCR for bioburden analysis.

    PubMed

    Schnetzinger, Franz; Pan, Youwen; Nocker, Andreas

    2013-03-01

    Rapid microbiological methods (RMMs) as an alternative to conventional cultivation-based bioburden analysis are receiving increasing attention although no single technology is currently able to satisfy the needs of the health care industry. Among the RMMs, quantitative PCR (qPCR) seems particularly suited. Its implementation is, however, hampered by false-positive signals originating from free DNA in PCR reagents or from dead cells in the samples to be analysed. In this study, we assessed the capability of propidium monoazide (PMA) to inactivate exogenous DNA in PCR reagents and thus to minimise its impact in bioburden analysis. PMA is a membrane-impermeant dye that intercalates into DNA and covalently binds to it upon photoactivation leading to strong inhibition of PCR amplification. PMA is currently used mainly for treatment of microbiological samples to exclude signals from membrane-compromised cells, but is also very useful for suppression of exogenous DNA signals. In addition to testing the effect of different PMA concentrations on non-template controls and target DNA, we demonstrate the effect of amplicon length on the exclusion of background amplification. Targeting a 1,108-bp 16S rRNA gene fragment using universal bacterial primers and PCR reagents treated with 5 μM PMA resulted in complete suppression of signals from exogenous DNA within 50 cycles of amplification, while a limit of detection of 10 copies of Escherichia coli genomic DNA per PCR reaction was achieved. A combined PMA treatment of sample and PCR reagents furthermore improved the selective detection of live cells making this method appear a highly attractive RMM.

  2. Frontal top-down signals increase coupling of auditory low-frequency oscillations to continuous speech in human listeners.

    PubMed

    Park, Hyojin; Ince, Robin A A; Schyns, Philippe G; Thut, Gregor; Gross, Joachim

    2015-06-15

    Humans show a remarkable ability to understand continuous speech even under adverse listening conditions. This ability critically relies on dynamically updated predictions of incoming sensory information, but exactly how top-down predictions improve speech processing is still unclear. Brain oscillations are a likely mechanism for these top-down predictions [1, 2]. Quasi-rhythmic components in speech are known to entrai