Sample records for janus kinase-signal transducer

  1. Dysregulation of janus kinases and signal transducers and activators of transcription in cancer

    PubMed Central

    Costa-Pereira, Ana P; Bonito, Nair A; Seckl, Michael J

    2011-01-01

    Despite their long recognised pivotal roles in immunological responses, Janus kinases (JAKs) and signal transducers and activators of transcription (STATs) are now seen as important players in cancer development and progression. Indeed, mutations in the JAKs are often found in myeloproliferative disorders (MPDs) and leukaemia, and the constitutive phosphorylation of STATs is a common occurrence in many solid and blood cancer cell lines and primary tumour specimens. More recently, we have also shown that JAKs likely have additional roles in promoting drug resistance in several cancer cell types. JAKs and STATs are thus molecules that may serve as useful targets in the clinic. This review will summarise studies that support this notion. PMID:22016828

  2. Tofacitinib Represses the Janus Kinase-Signal Transducer and Activators of Transcription Signalling Pathway in Keratinocytes.

    PubMed

    Srivastava, Ankit; Ståhle, Mona; Pivarcsi, Andor; Sonkoly, Enikö

    2018-05-08

    Tofacitinib is a Janus kinase (JAK) inhibitor, which has shown efficacy in treating psoriasis. The mode of action of tofacitinib is not completely understood but it has been thought to be mediated by the inhibition of CD4+ T-cell activation. Here, we investigated whether the molecular targets of tofacitinib are expressed in keratinocytes, and whether tofacitinib can modulate the activity of the JAK/Signal Transducer and Activators of Transcription (STAT)-pathway in keratinocytes. Transcriptomic profiling of human keratinocytes treated with IL-22 in combination with tofacitinib revealed that tofacitinib could prevent the majority of IL-22-mediated gene expression changes. Pathway analysis of tofacitinib-regulated genes in keratinocytes revealed enrichment of genes involved in the JAK/STAT signalling pathway. Quantitative real-time-PCR confirmed the upregulation of S100A7 and downregulation of EGR1 expression by IL-22, which was prevented by tofacitinib pre-treatment. These results indicate a direct effect of tofacinitib on keratinocytes, which can have relevance for systemic as well as for topical treatment of psoriasis with tofacitinib.

  3. The Future of Janus Kinase Inhibitors in Inflammatory Bowel Disease

    PubMed Central

    De Vries, L.C.S.; Wildenberg, M.E.; De Jonge, W.J.

    2017-01-01

    Abstract Inflammatory bowel diseases, such as ulcerative colitis and Crohn’s disease, are disabling conditions characterised by chronic, relapsing inflammation of the gastrointestinal tract. Current treatments are not universally effective or, in the case of therapeutic antibodies, are hampered by immune responses. Janus kinase inhibitors are orally delivered small molecules that target cytokine signalling by preventing phosphorylation of Janus kinases associated with the cytokine receptor. Subsequently, phosphorylation of signal transducers and activators of transcription that relay Janus kinase signalling and transcription of cytokines in the nucleus will be diminished. Key cytokines in the pathogenesis of inflammatory bowel diseases are targeted by Janus kinase inhibitors. Several Janus kinase inhibitors are in development for the treatment of inflammatory bowel diseases. Tofacitinib, inhibiting signalling via all Janus kinase family members, was effective in phase 2 and 3 trials in moderate-severe ulcerative colitis. GSK2586184, a Janus kinase 1 selective inhibitor, induced clinical and endoscopic response in ulcerative colitis; however, the study was discontinued at an early stage due to liver toxicity observed in systemic lupus patients receiving the drug. Filgotinib, a Janus kinase 1 selective inhibitor investigated in treatment of Crohn’s disease, was superior to placebo. As adverse events associated with the broad immunological effect of these agents have been reported, the future application of these drugs is potentially limited. We will discuss the treatment efficacy of Janus kinase inhibition in inflammatory bowel diseases, how current Janus kinase inhibitors available target immune responses relevant in inflammatory bowel disease, and whether more specific kinase inhibition could be effective. PMID:28158411

  4. The Future of Janus Kinase Inhibitors in Inflammatory Bowel Disease.

    PubMed

    De Vries, L C S; Wildenberg, M E; De Jonge, W J; D'Haens, G R

    2017-07-01

    Inflammatory bowel diseases, such as ulcerative colitis and Crohn's disease, are disabling conditions characterised by chronic, relapsing inflammation of the gastrointestinal tract. Current treatments are not universally effective or, in the case of therapeutic antibodies, are hampered by immune responses. Janus kinase inhibitors are orally delivered small molecules that target cytokine signalling by preventing phosphorylation of Janus kinases associated with the cytokine receptor. Subsequently, phosphorylation of signal transducers and activators of transcription that relay Janus kinase signalling and transcription of cytokines in the nucleus will be diminished. Key cytokines in the pathogenesis of inflammatory bowel diseases are targeted by Janus kinase inhibitors. Several Janus kinase inhibitors are in development for the treatment of inflammatory bowel diseases. Tofacitinib, inhibiting signalling via all Janus kinase family members, was effective in phase 2 and 3 trials in moderate-severe ulcerative colitis. GSK2586184, a Janus kinase 1 selective inhibitor, induced clinical and endoscopic response in ulcerative colitis; however, the study was discontinued at an early stage due to liver toxicity observed in systemic lupus patients receiving the drug. Filgotinib, a Janus kinase 1 selective inhibitor investigated in treatment of Crohn's disease, was superior to placebo. As adverse events associated with the broad immunological effect of these agents have been reported, the future application of these drugs is potentially limited. We will discuss the treatment efficacy of Janus kinase inhibition in inflammatory bowel diseases, how current Janus kinase inhibitors available target immune responses relevant in inflammatory bowel disease, and whether more specific kinase inhibition could be effective. © European Crohn’s and Colitis Organisation (ECCO) 2017.

  5. Phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) and Janus kinase/signal transducer and activator of transcription (JAK/STAT) follicular signalling is conserved in the mare ovary.

    PubMed

    Hall, Sally E; Upton, Rose M O; McLaughlin, Eileen A; Sutherland, Jessie M

    2017-09-26

    The mare ovary is unique in its anatomical structure; however, the signalling pathways responsible for physiological processes, such as follicular activation, remain uncharacterised. This provided us with the impetus to explore whether signalling molecules from important folliculogenesis pathways, phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) and Janus kinase/signal transducer and activator of transcription (JAK/STAT), are conserved in the mare ovary. Messenger RNA expression of six genes important in follicle development was measured using quantitative polymerase chain reaction and protein localisation of key pathway members (PI3K, AKT1, phosphatase and tensin homologue (PTEN), JAK1, STAT3 and suppressor of cytokine signalling 4 (SOCS4)) was compared in tissue from fetal and adult mare ovaries. Tissue from adult ovaries exhibited significantly increased levels of mRNA expression of PI3K, AKT1, PTEN, JAK1, STAT3 and SOCS4 compared with tissue from fetal ovaries. PI3K, AKT1, JAK1 and STAT3 demonstrated redistributed localisation, from pregranulosa cells in fetal development, to both the oocyte and granulosa cells of follicles in the adult ovary, whilst negative feedback molecules PTEN and SOCS4 were only localised to the granulosa cells in the adult ovary. These findings suggest that the PI3K/AKT and JAK/STAT signalling pathways are utilised during folliculogenesis in the mare, similarly to previously studied mammalian species, and may serve as useful biomarkers for assessment of ovary development in the horse.

  6. Interplay between Janus Kinase/Signal Transducer and Activator of Transcription Signaling Activated by Type I Interferons and Viral Antagonism

    PubMed Central

    Nan, Yuchen; Wu, Chunyan; Zhang, Yan-Jin

    2017-01-01

    Interferons (IFNs), which were discovered a half century ago, are a group of secreted proteins that play key roles in innate immunity against viral infection. The major signaling pathway activated by IFNs is the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway, which leads to the expression of IFN-stimulated genes (ISGs), including many antiviral effectors. Viruses have evolved various strategies with which to antagonize the JAK/STAT pathway to influence viral virulence and pathogenesis. In recent years, notable progress has been made to better understand the JAK/STAT pathway activated by IFNs and antagonized by viruses. In this review, recent progress in research of the JAK/STAT pathway activated by type I IFNs, non-canonical STAT activation, viral antagonism of the JAK/STAT pathway, removing of the JAK/STAT antagonist from viral genome for attenuation, and the potential pathogenesis roles of tyrosine phosphorylation-independent non-canonical STATs activation during virus infection are discussed in detail. We expect that this review will provide new insight into the understanding the complexity of the interplay between JAK/STAT signaling and viral antagonism. PMID:29312301

  7. Janus kinase (JAK) inhibitors in the treatment of inflammatory and neoplastic diseases.

    PubMed

    Roskoski, Robert

    2016-09-01

    The Janus kinase (JAK) family of non-receptor protein-tyrosine kinases consists of JAK1, JAK2, JAK3, and TYK2 (tyrosine kinase-2). Each of these proteins contains a JAK homology pseudokinase (JH2) domain that regulates the adjacent protein kinase domain (JH1). JAK1/2 and TYK2 are ubiquitously expressed whereas JAK3 is found predominantly in hematopoietic cells. The Janus kinase family is regulated by numerous cytokines including interleukins, interferons, and hormones such as erythropoietin, thrombopoietin, and growth hormone. Ligand binding to cytokine and hormone receptors leads to the activation of associated Janus kinases, which then mediate the phosphorylation of the receptors. The SH2 domain of STATs (signal transducers and activators of transcription) binds to the receptor phosphotyrosines thereby promoting STAT phosphorylation by the Janus kinases and consequent activation. STAT dimers are translocated to the nucleus where they participate in the regulation of the expression of thousands of proteins. JAK-STAT dysregulation results in autoimmune disorders such as rheumatoid arthritis, ulcerative colitis, and Crohn disease. JAK-STAT dysregulation also plays a role in the pathogenesis of myelofibrosis, polycythemia vera, and other myeloproliferative illnesses. An activating JAK2 V617F mutation occurs in 95% of people with polycythemia vera and in a lower percentage of people with other neoplasms. JAK1/3 signaling participates in the pathogenesis of inflammatory afflictions while JAK1/2 signaling participates in the development of several malignancies including leukemias and lymphomas as well as myeloproliferative neoplasms. Tofacitinib is a pan-JAK inhibitor that is approved by the FDA for the treatment of rheumatoid arthritis and ruxolitinib is a JAK1/2 inhibitor that is approved for the treatment of polycythemia vera and myelofibrosis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Leptin modulates the expression of catabolic genes in rat nucleus pulposus cells through the mitogen-activated protein kinase and Janus kinase 2/signal transducer and activator of transcription 3 pathways.

    PubMed

    Miao, Daoyi; Zhang, Lingzhou

    2015-08-01

    Obesity has been demonstrated to be involved in the progress of intervertebral disc degeneration (IDD). However, the associated mechanisms remain to be elucidated. The purpose the present study was to examine the effect of leptin on the expression of degeneration-associated genes in rat nucleus pulposus (NP) cells, and determine the possible mechanism. Normal NP cells, obtained from Sprague Dawley rats, were identified using immunocytochemistry for the expression of collagen II and CA125, and treated with leptin and/or interleukin (IL)-β. Subsequently, the mRNA expression levels of matrix metalloproteinase (MMP)-1, MMP-3, MMP-9, MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4, ADAMTS-5, aggrecan and COL2A1 were detected by reverse transcription-quantitative polymerase chain reaction (RT-q-PCR). Alcian staining and immunocytochemistry were used to examine the expression levels of proteoglycan and collagen II. The pathway activation was investigated using western blotting, and inhibitors of the pathways were used to reveal the effect of these pathways on the NP cells. The results of the RT-qPCR demonstrated that leptin alone upregulated the mRNA expression levels of MMP-1, MMP-13, ADAMTS-4, ADAMTS-5 and COL2A1. Synergy of leptin and IL-β was found in the increased expression levels of MMP-1, MMP-3 and ADAMTS-5. The leptin-treated NP cells exhibited decreased expression of collagen II. The mitrogen-activated protein kinase (MAPK) pathway (c-Jun-N-terminal kinase, phosphorylated extracellular signal-regulated kinase and p38), phosphatidylinositol 3-kinase (PI3K)/Akt pathway and Janus kinase (JAK)2/signal transducer and activator of transcription 3 pathway were all activated by leptin, however, inhibitors of all the pathways, with the exception of the PI3K/Akt pathway, reversed the expression levels of MMP-1 and MMP-13. These results suggested that leptin promoted catabolic metabolism in the rat NP cells via the MAPK and JAK2/STAT3

  9. Leptin modulates the expression of catabolic genes in rat nucleus pulposus cells through the mitogen-activated protein kinase and Janus kinase 2/signal transducer and activator of transcription 3 pathways

    PubMed Central

    MIAO, DAOYI; ZHANG, LINGZHOU

    2015-01-01

    Obesity has been demonstrated to be involved in the progress of intervertebral disc degeneration (IDD). However, the associated mechanisms remain to be elucidated. The purpose the present study was to examine the effect of leptin on the expression of degeneration-associated genes in rat nucleus pulposus (NP) cells, and determine the possible mechanism. Normal NP cells, obtained from Sprague Dawley rats, were identified using immunocytochemistry for the expression of collagen II and CA125, and treated with leptin and/or interleukin (IL)-β. Subsequently, the mRNA expression levels of matrix metalloproteinase (MMP)-1, MMP-3, MMP-9, MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4, ADAMTS-5, aggrecan and COL2A1 were detected by reverse transcription-quantitative polymerase chain reaction (RT-q-PCR). Alcian staining and immunocytochemistry were used to examine the expression levels of proteoglycan and collagen II. The pathway activation was investigated using western blotting, and inhibitors of the pathways were used to reveal the effect of these pathways on the NP cells. The results of the RT-qPCR demonstrated that leptin alone upregulated the mRNA expression levels of MMP-1, MMP-13, ADAMTS-4, ADAMTS-5 and COL2A1. Synergy of leptin and IL-β was found in the increased expression levels of MMP-1, MMP-3 and ADAMTS-5. The leptin-treated NP cells exhibited decreased expression of collagen II. The mitrogen-activated protein kinase (MAPK) pathway (c-Jun-N-terminal kinase, phosphorylated extracellular signal-regulated kinase and p38), phosphatidylinositol 3-kinase (PI3K)/Akt pathway and Janus kinase (JAK)2/signal transducer and activator of transcription 3 pathway were all activated by leptin, however, inhibitors of all the pathways, with the exception of the PI3K/Akt pathway, reversed the expression levels of MMP-1 and MMP-13. These results suggested that leptin promoted catabolic metabolism in the rat NP cells via the MAPK and JAK2/STAT3

  10. Mangiferin ameliorates Porphyromonas gingivalis-induced experimental periodontitis by inhibiting phosphorylation of nuclear factor-κB and Janus kinase 1-signal transducer and activator of transcription signaling pathways.

    PubMed

    Li, H; Wang, Q; Ding, Y; Bao, C; Li, W

    2017-02-01

    Mangiferin is a natural polyphenol compound with anti-inflammatory properties. However, there have been few reports on the effect of mangiferin on periodontitis. Here, we investigated the anti-inflammatory effects of this compound on experimental periodontitis and the underlying mechanisms. Mice were inoculated with Porphyromonas gingivalis to induce periodontitis, and treated with mangiferin orally (50 mg/kg bodyweight, once a day) for 8 wk. Then, the alveolar bone loss was examined using a scanning electronic microscope. Expression of tumor necrosis factor-α (TNF-α) and the phosphorylation levels of nuclear factor-κB (NF-κB) and Janus kinase 1-signal transducer and activator of adhesion (JAK1-STAT) pathways in the gingival epithelium were detected using western blot analysis and immunohistochemical staining. The results showed that mice with periodontitis exhibited greater alveolar bone loss, stronger expression of TNF-α and higher phosphorylation levels of NF-κB and JAK1-STAT1/3 pathways in gingival epithelia, compared with control mice with no periodontitis. Moreover, treatment with mangiferin could significantly inhibit alveolar bone loss, TNF-α production and phosphorylation of NF-κB and JAK1-STAT1/3 pathways in gingival epithelia. Mangiferin has anti-inflammatory effects on periodontitis, which is associated with its ability to down-regulate the phosphorylation of NF-κB and JAK1-STAT1/3 pathways in gingival epithelia. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. The two faces of Janus kinases and their respective STATs in mammary gland development and cancer.

    PubMed

    Wagner, Kay-Uwe; Schmidt, Jeffrey W

    2011-01-01

    Since its discovery as "just another kinase" more than twenty years ago, the family of JAK tyrosine kinases and their respective Signal Transducers and Activators of Transcription (STATs) has been a center of attention in the areas of signal transduction, development, and cancer. The subsequent designation of JAKs as Janus kinases after the mythical two-faced Roman God of the doorways accurately portrays the analogous and sometimes contrasting molecular and biological characteristics of these tyrosine kinases. The two "faces" of JAKs are their structurally similar kinase and pseudo-kinase domains. As essential parts of various transmembrane receptor complexes, these tyrosine kinases function at cellular gateways and relay signals from growth factors to their respective intracellular targets. The multifaceted nature of JAKs becomes evident from their ability to activate specific STATs during distinct phases of normal mammary gland development. Studies in breast cancer cells and genetically engineered mouse models also show that JAK/STAT signaling possesses a "two-faced" role during breast cancer initiation and progression. This review will highlight recent findings about important biological functions of JAKs and STATs during normal mammogenesis, with particular emphasis on the Jak2/Stat5 pathway as well as Jak1/2/Stat3 signaling complexes. In addition, we will discuss how the importance of these signaling networks changes during carcinogenesis. With JAK inhibitors currently under development to treat myeloproliferative disorders, determining the essential functions of JAKs at particular stages of disease initiation and progression is of critical importance to predict the efficacy of these agents for targeted therapies against breast cancer.

  12. The two faces of Janus kinases and their respective STATs in mammary gland development and cancer

    PubMed Central

    Wagner, Kay-Uwe; Schmidt, Jeffrey W.

    2011-01-01

    Since its discovery as “just another kinase” more than twenty years ago, the family of JAK tyrosine kinases and their respective Signal Transducers and Activators of Transcription (STATs) has been a center of attention in the areas of signal transduction, development, and cancer. The subsequent designation of JAKs as Janus kinases after the mythical two-faced Roman God of the doorways accurately portrays the analogous and sometimes contrasting molecular and biological characteristics of these tyrosine kinases. The two “faces” of JAKs are their structurally similar kinase and pseudo-kinase domains. As essential parts of various transmembrane receptor complexes, these tyrosine kinases function at cellular gateways and relay signals from growth factors to their respective intracellular targets. The multifaceted nature of JAKs becomes evident from their ability to activate specific STATs during distinct phases of normal mammary gland development. Studies in breast cancer cells and genetically engineered mouse models also show that JAK/STAT signaling possesses a "two-faced" role during breast cancer initiation and progression. This review will highlight recent findings about important biological functions of JAKs and STATs during normal mammogenesis, with particular emphasis on the Jak2/Stat5 pathway as well as Jak1/2/Stat3 signaling complexes. In addition, we will discuss how the importance of these signaling networks changes during carcinogenesis. With JAK inhibitors currently under development to treat myeloproliferative disorders, determining the essential functions of JAKs at particular stages of disease initiation and progression is of critical importance to predict the efficacy of these agents for targeted therapies against breast cancer. PMID:22279417

  13. Activation of the protein tyrosine phosphatase SHP2 via the interleukin-6 signal transducing receptor protein gp130 requires tyrosine kinase Jak1 and limits acute-phase protein expression.

    PubMed

    Schaper, F; Gendo, C; Eck, M; Schmitz, J; Grimm, C; Anhuf, D; Kerr, I M; Heinrich, P C

    1998-11-01

    Stimulation of the interleukin-6 (IL-6) signalling pathway occurs via the IL-6 receptor-glycoprotein 130 (IL-6R-gp130) receptor complex and results in the regulation of acute-phase protein genes in liver cells. Ligand binding to the receptor complex leads to tyrosine phosphorylation and activation of Janus kinases (Jak), phosphorylation of the signal transducing subunit gp130, followed by recruitment and phosphorylation of the signal transducer and activator of transcription factors STAT3 and STAT1 and the src homology domain (SH2)-containing protein tyrosine phosphatase (SHP2). The tyrosine phosphorylated STAT factors dissociate from the receptor, dimerize and translocate to the nucleus where they bind to enhancer sequences of IL-6 target genes. Phosphorylated SHP2 is able to bind growth factor receptor bound protein (grb2) and thus might link the Jak/STAT pathway to the ras/raf/mitogen-activated protein kinase pathway. Here we present data on the dose-dependence, kinetics and kinase requirements for SHP2 phosphorylation after the activation of the signal transducer, gp130, of the IL-6-type family receptor complex. When human fibrosarcoma cell lines deficient in Jak1, Jak2 or tyrosine kinase 2 (Tyk2) were stimulated with IL-6-soluble IL-6R complexes it was found that only in Jak1-, but not in Jak 2- or Tyk2-deficient cells, SHP2 activation was greatly impaired. It is concluded that Jak1 is required for the tyrosine phosphorylation of SHP2. This phosphorylation depends on Tyr-759 in the cytoplasmatic domain of gp130, since a Tyr-759-->Phe exchange abrogates SHP2 activation and in turn leads to elevated and prolonged STAT3 and STAT1 activation as well as enhanced acute-phase protein gene induction. Therefore, SHP2 plays an important role in acute-phase gene regulation.

  14. Signal Transducers and Activators of Transcription (STAT) family members in helminth infections.

    PubMed

    Becerra-Díaz, Mireya; Valderrama-Carvajal, Héctor; Terrazas, Luis I

    2011-01-01

    Helminth parasites are a diverse group of multicellular organisms. Despite their heterogeneity, helminths share many common characteristics, such as the modulation of the immune system of their hosts towards a permissive state that favors their development. They induce strong Th2-like responses with high levels of IL-4, IL-5 and IL-13 cytokines, and decreased production of proinflammatory cytokines such as IFN-γ. IL-4, IFN-γ and other cytokines bind with their specific cytokine receptors to trigger an immediate signaling pathway in which different tyrosine kinases (e.g. Janus kinases) are involved. Furthermore, a seven-member family of transcription factors named Signal Transducers and Activators of Transcription (STAT) that initiate the transcriptional activation of different genes are also involved and regulate downstream the JAK/STAT signaling pathway. However, how helminths avoid and modulate immune responses remains unclear; moreover, information concerning STAT-mediated immune regulation during helminth infections is scarce. Here, we review the research on mice deficient in STAT molecules, highlighting the importance of the JAK/STAT signaling pathway in regulating susceptibility and/or resistance in these infections.

  15. Molecular modeling-driven approach for identification of Janus kinase 1 inhibitors through 3D-QSAR, docking and molecular dynamics simulations.

    PubMed

    Itteboina, Ramesh; Ballu, Srilata; Sivan, Sree Kanth; Manga, Vijjulatha

    2017-10-01

    Janus kinase 1 (JAK 1) belongs to the JAK family of intracellular nonreceptor tyrosine kinase. JAK-signal transducer and activator of transcription (JAK-STAT) pathway mediate signaling by cytokines, which control survival, proliferation and differentiation of a variety of cells. Three-dimensional quantitative structure activity relationship (3 D-QSAR), molecular docking and molecular dynamics (MD) methods was carried out on a dataset of Janus kinase 1(JAK 1) inhibitors. Ligands were constructed and docked into the active site of protein using GLIDE 5.6. Best docked poses were selected after analysis for further 3 D-QSAR analysis using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) methodology. Employing 60 molecules in the training set, 3 D-QSAR models were generate that showed good statistical reliability, which is clearly observed in terms of r 2 ncv and q 2 loo values. The predictive ability of these models was determined using a test set of 25 molecules that gave acceptable predictive correlation (r 2 Pred ) values. The key amino acid residues were identified by means of molecular docking, and the stability and rationality of the derived molecular conformations were also validated by MD simulation. The good consonance between the docking results and CoMFA/CoMSIA contour maps provides helpful clues about the reasonable modification of molecules in order to design more efficient JAK 1 inhibitors. The developed models are expected to provide some directives for further synthesis of highly effective JAK 1 inhibitors.

  16. Desensitization of the growth hormone-induced Janus kinase 2 (Jak 2)/signal transducer and activator of transcription 5 (Stat5)-signaling pathway requires protein synthesis and phospholipase C.

    PubMed

    Fernández, L; Flores-Morales, A; Lahuna, O; Sliva, D; Norstedt, G; Haldosén, L A; Mode, A; Gustafsson, J A

    1998-04-01

    Signal transducers and activators of transcription (Stat) proteins are latent cytoplasmic transcription factors that are tyrosine phosphorylated by Janus kinases (Jak) in response to GH and other cytokines. GH activates Stat5 by a mechanism that involves tyrosine phosphorylation and nuclear translocation. However, the mechanisms that turn off the GH-activated Jak2/Stat5 pathway are unknown. Continuous exposure to GH of BRL-4 cells, a rat hepatoma cell line stably transfected with rat GH receptor, induces a rapid but transient activation of Jak2 and Stat5. GH-induced Stat5 DNA-binding activity was detected after 2 min and reached a maximum at 10 min. Continued exposure to GH resulted in a desensitization characterized by 1) a rapid decrease in Stat5 DNA-binding activity. The rate of decrease of activity was rapid up to 1 h of GH treatment, and the remaining activity declined slowly thereafter. The activity of Stat5 present after 5 h is still higher than the control levels and almost 10-20% with respect to maximal activity at 10 min; and 2) the inability of further GH treatment to reinduce activation of Stat5. In contrast, with transient exposures of BRL-4 cells to GH, Stat5 DNA-binding activity could repeatedly be induced. GH-induced Jak2 and Stat5 activities were independent of ongoing protein synthesis. However, Jak2 tyrosine phosphorylation and Stat5 DNA-binding activity were prolonged for at least 4 h in the presence of cycloheximide, which suggests that the maintenance of desensitization requires ongoing protein synthesis. Furthermore, inhibition of protein synthesis potentiated GH-induced transcriptional activity in BRL-4 cells transiently transfected with SPIGLE1CAT, a reporter plasmid activated by Stat5. GH-induced Jak2 and Stat5 activation were not affected by D609 or mepacrine, both inhibitors of phospholipase C. However, in the presence of D609 and mepacrine, GH maintained prolonged Jak2 and Stat5 activation. Transactivation of SPIGLE1 by GH was

  17. Role of STATs as downstream signal transducers in Src family kinase-mediated tumorigenesis.

    PubMed

    Silva, Corinne M

    2004-10-18

    The signal transducers and activators of transcription (STATs) were originally identified in the signaling pathway activated by the nontyrosine kinase containing cytokine receptors. The role of these STATs in hematopoietic cell signaling has been well described. In the case of cytokine receptors, activation of STAT tyrosine phosphorylation occurs through ligand-induced recruitment, and activation of the intracellular JAK kinases. However, STATs can also be activated by growth factor receptors, particularly the EGFR; as well as by members of the Src Family of Kinases (SFKs), particularly c-Src. In many cases, there is a differential activation of the STATs by these tyrosine kinases as compared to activation by the cytokine receptors. This difference provides for the potential of unique actions of STATs in response to growth factor receptor and SFK activation. Since there are many cancers in which SFKs and c-Src in particular, are co-overexpressed with growth factor receptors, it is not surprising that STATs play an important role in the tumorigenesis process induced by c-Src. The activation paradigm and role of STATs in these cancers, with particular emphasis on breast cancer models, is discussed.

  18. Propofol mediates signal transducer and activator of transcription 3 activation and crosstalk with phosphoinositide 3-kinase/AKT.

    PubMed

    Shravah, Jayant; Wang, Baohua; Pavlovic, Marijana; Kumar, Ujendra; Chen, David Dy; Luo, Honglin; Ansley, David M

    2014-01-01

    We previously demonstrated that propofol, an intravenous anesthetic with anti-oxidative properties, activated the phosphoinositide 3-kinase (PI3K)/AKT pathway to increase the expression of B cell lymphoma (Bcl)-2 and, therefore the anti-apoptotic potential on cardiomyocytes. Here, we wanted to determine if propofol can also activate the Janus kinase (JAK) 2/signal transducer and activator of transcription (STAT) 3 pathway, another branch of cardioprotective signaling. The cellular response of nuclear factor kappa B (NFκB) and STAT3 was also evaluated. Cardiac H9c2 cells were treated by propofol alone or in combination with pretreatment by inhibitors for JAK2/STAT3 or PI3K/AKT pathway. STAT3 and AKT phosphorylation, and STAT3 translocation were measured by western blotting and immunofluorescence staining, respectively. Propofol treatment significantly increased STAT3 phosphorylation at both tyrosine 705 and serine 727 residues. Sustained early phosphorylation of STAT3 was observed with 25~75 μM propofol at 10 and 30 min. Nuclear translocation of STAT3 was seen at 4 h after treatment with 50 μM propofol. In cultured H9c2 cells, we further demonstrated that propofol-induced STAT3 phosphorylation was reduced by pretreatment with PI3K/AKT pathway inhibitors wortmannin or API-2. Conversely, pretreatment with JAK2/STAT3 pathway inhibitor AG490 or stattic inhibited propofol-induced AKT phosphorylation. In addition, propofol induced NFκB p65 subunit perinuclear translocation. Inhibition or knockdown of STAT3 was associated with increased levels of the NFκB p65 subunit. Our results suggest that propofol induces an adaptive response by dual activation and crosstalk of cytoprotective PI3K/AKT and JAK2/STAT3 pathways. Rationale to apply propofol clinically as a preemptive cardioprotectant during cardiac surgery is supported by our findings.

  19. Advances in the Development of Janus Kinase Inhibitors in Inflammatory Bowel Disease: Future Prospects.

    PubMed

    Flamant, Mathurin; Rigaill, Josselin; Paul, Stephane; Roblin, Xavier

    2017-07-01

    Inflammatory bowel disease (IBD) is caused by a dysregulation of the immune system, inducing the production of proinflammatory cytokines and adhesion molecules. A better understanding of the mucosal immune response in IBD has led to the development of new drugs directed at inflammatory cytokines and leukocyte-trafficking molecules. Beyond tumor necrosis factor antagonists and anti-integrin molecules, which act by blocking the interaction between gut-specific lymphocytes and their receptor on vascular endothelium, the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway represents a new target in IBD. JAK inhibitors are small molecules able to selectively target the activity of specific JAKs that play a role in signal transmission via interleukins. This review presents an overview of the role of the JAK/STAT signaling pathway and updated information for JAK molecules, which are promising drugs in IBD. Currently developed to treat ulcerative colitis and Crohn's disease, tofacitinib (in a phase III study) and filgotinib (in a phase II study), respectively, are the JAK inhibitors in the most advanced stage of development for IBD. However, the utility of, and adverse events associated with, these new drugs remain to be determined and clarified (in particular, the risk of herpes zoster infections), depending on the efficacy and tolerance determined from definitive studies. The availability of these drugs could enhance the therapeutic approach to IBD in the coming years, and reinforce the concept of personalized medicine for IBD patients.

  20. Intravenous transplantation of mesenchymal stromal cells has therapeutic effects in a sepsis mouse model through inhibition of septic natural killer cells.

    PubMed

    Liu, Wenhua; Gao, Yang; Li, Haibo; Wang, Hongliang; Ye, Ming; Jiang, Guihua; Chen, Yongsheng; Liu, Yang; Kong, Junying; Liu, Wei; Sun, Meng; Hou, Meng; Yu, Kaijiang

    2016-10-01

    Transplantation of mesenchymal stromal cells is a promising strategy for treating sepsis. Natural killer cells are important in the development of sepsis, and their functions can be inhibited by mesenchymal stromal cells, we asked whether mesenchymal stromal cells exert their therapeutic effects through inhibiting the functions of natural killer cells in a septic mouse model generated with cecal ligation puncture method. Using co-cultures of cells, small interfering RNA, enzyme-linked immnuosorbent assays, fluorescence assays, western blotting, and pathological examination, we investigated the levels of inflammatory cytokines, proliferation of natural killer cells, inflammatory infiltration of important organs in mice, and activity of the Janus kinase/signal transducer and activator of transcription signaling pathway and found that mesenchymal stromal cells inhibited the function and proliferation of septic natural killer cells, increased interleukin-10 levels and increased the expression of components, such as Janus kinase 1, Janus kinase 2, and signal transducer and activator of transcription 3 in the Janus kinase/signal transducer and activator of transcription pathway both in vitro and in vivo. We conclude that mesenchymal stromal cells have their therapeutic effect in the septic mouse model through inhibiting the function and proliferation of septic natural killer cells. This biological process may involve interleukin-10 and suppressor of cytokine signaling 3 as well as other pathway components in the Janus kinase/signal transducer and activator of transcription pathway. Transplantation of mesenchymal stromal cells is an effective strategy to treat sepsis. Copyright © 2016. Published by Elsevier Ltd.

  1. High mobility group box 1 induces the activation of the Janus kinase 2 and signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway in pancreatic acinar cells in rats, while AG490 and rapamycin inhibit their activation.

    PubMed

    Wang, Guoliang; Zhang, Jingchao; Dui, Danhua; Ren, Haoyuan; Liu, Jin

    2016-11-10

    The pathogenesis of severe acute pancreatitis (SAP) remains unclear. The Janus kinase and signal transducer and activator of transcription (JAK/STAT) pathway is important for various cytokines and growth factors. This study investigated the effect of the late inflammatory factor high mobility group box 1 (HMGB1) on the activation of JAK2/STAT3 in pancreatic acinar cells and the inhibitory effects of AG490 (a JAK2 inhibitor) and rapamycin (a STAT3 inhibitor) on this pathway. Rat pancreatic acinar cells were randomly divided into the control, HMGB1, AG490, and rapamycin groups. The mRNA levels of JAK2 and STAT3 at 10, 30, 60, and 120 minutes were detected using reverse transcription polymerase chain reaction (RT-PCR). The protein levels of JAK2 and STAT3 at 60 and 120 minutes were observed using Western blotting. Compared with the control group, the HMGB1 group exhibited significantly increased levels of JAK2 mRNA at each time point; STAT3 mRNA at 30, 60, and 120 minutes; and JAK2 and STAT3 proteins at 60 and 120 minutes (p < 0.01). Compared with the HMGB1 group, the AG490 and rapamycin groups both exhibited significantly decreased levels of JAK2 mRNA at each time point (p < 0.05); STAT3 mRNA at 30, 60, and 120 minutes (p < 0.01); and JAK2 and STAT3 proteins at 60 and 120 minutes (p < 0.01). HMGB1 induces the activation of the JAK2/STAT3 signaling pathway in rat pancreatic acinar cells, and this activation can be inhibited by AG490 and rapamycin. The results of this study may provide new insights for the treatment of SAP.

  2. Newer treatments of psoriasis regarding IL-23 inhibitors, phosphodiesterase 4 inhibitors, and Janus kinase inhibitors.

    PubMed

    Wcisło-Dziadecka, Dominika; Zbiciak-Nylec, Martyna; Brzezińska-Wcisło, Ligia; Bebenek, Katarzyna; Kaźmierczak, Agata

    2017-11-01

    The rapid progress of genetic engineering furthermore opens up new prospects in the therapy of this difficult-to-treat disease. IL-23 inhibitors, phosphodiesterase 4 (PDE4) inhibitors, and Janus kinase (JAK) inhibitors are currently encouraging further research. Two drugs which are IL-23 inhibitors are now in phase III of clinical trials. The aim of the action of both drugs is selective IL-23 inhibition by targeting the p19 subunit. Guselkumab is a fully human monoclonal antibody. Tildrakizumab is a humanized monoclonal antibody, which also belongs to IgG class and is targeted to subunit p19 of interleukin 23 (IL-23). Phosphodiesterase inhibitors exert an anti-inflammatory action and their most common group is the PDE4 family. PDE4 inhibits cAMP, which reduces the inflammatory response of the pathway of Th helper lymphocytes, Th17, and type 1 interferon which modulates the production of anti-inflammatory cytokines such as IL-10 interleukins. The Janus kinase (JAK) signaling pathway plays an important role in the immunopathogenesis of psoriasis. Tofacitinib suppresses the expression of IL-23, IL-17A, IL-17F, and IL-22 receptors during the stimulation of lymphocytes. Ruxolitinib is a selective inhibitor of JAK1 and JAK2 kinases and the JAK-STAT signaling pathway. This article is a review of the aforementioned drugs as described in the latest available literature. © 2017 Wiley Periodicals, Inc.

  3. Stress Sensors and Signal Transducers in Cyanobacteria

    PubMed Central

    Los, Dmitry A.; Zorina, Anna; Sinetova, Maria; Kryazhov, Sergey; Mironov, Kirill; Zinchenko, Vladislav V.

    2010-01-01

    In living cells, the perception of environmental stress and the subsequent transduction of stress signals are primary events in the acclimation to changes in the environment. Some molecular sensors and transducers of environmental stress cannot be identified by traditional and conventional methods. Based on genomic information, a systematic approach has been applied to the solution of this problem in cyanobacteria, involving mutagenesis of potential sensors and signal transducers in combination with DNA microarray analyses for the genome-wide expression of genes. Forty-five genes for the histidine kinases (Hiks), 12 genes for serine-threonine protein kinases (Spks), 42 genes for response regulators (Rres), seven genes for RNA polymerase sigma factors, and nearly 70 genes for transcription factors have been successfully inactivated by targeted mutagenesis in the unicellular cyanobacterium Synechocystis sp. PCC 6803. Screening of mutant libraries by genome-wide DNA microarray analysis under various stress and non-stress conditions has allowed identification of proteins that perceive and transduce signals of environmental stress. Here we summarize recent progress in the identification of sensory and regulatory systems, including Hiks, Rres, Spks, sigma factors, transcription factors, and the role of genomic DNA supercoiling in the regulation of the responses of cyanobacterial cells to various types of stress. PMID:22294932

  4. Similarities and differences in signal transduction by interleukin 4 and interleukin 13: analysis of Janus kinase activation.

    PubMed

    Keegan, A D; Johnston, J A; Tortolani, P J; McReynolds, L J; Kinzer, C; O'Shea, J J; Paul, W E

    1995-08-15

    The cytokines interleukin (IL) 4 and IL-13 induce many of the same biological responses, including class switching to IgE and induction of major histocompatibility complex class II antigens and CD23 on human B cells. It has recently been shown that IL-4 induces the tyrosine phosphorylation of a 170-kDa protein, a substrate called 4PS, and of the Janus kinase (JAK) family members JAK1 and JAK3. Because IL-13 has many functional effects similar to those of IL-4, we compared the ability of IL-4 and IL-13 to activate these signaling molecules in the human multifactor-dependent cell line TF-1. In this report we demonstrate that both IL-4 and IL-13 induced the tyrosine phosphorylation of 4PS and JAK1. Interestingly, although IL-4 induced the tyrosine phosphorylation of JAK3, we did not detect JAK3 phosphorylation in response to IL-13. These data suggest that IL-4 and IL-13 signal in similar ways via the activation of JAK1 and 4PS. However, our data further indicate that there are significant differences because IL-13 does not activate JAK3.

  5. Molecular docking, 3D QSAR and dynamics simulation studies of imidazo-pyrrolopyridines as janus kinase 1 (JAK 1) inhibitors.

    PubMed

    Itteboina, Ramesh; Ballu, Srilata; Sivan, Sree Kanth; Manga, Vijjulatha

    2016-10-01

    Janus kinase 1 (JAK 1) plays a critical role in initiating responses to cytokines by the JAK-signal transducer and activator of transcription (JAK-STAT). This controls survival, proliferation and differentiation of a variety of cells. Docking, 3D quantitative structure activity relationship (3D-QSAR) and molecular dynamics (MD) studies were performed on a series of Imidazo-pyrrolopyridine derivatives reported as JAK 1 inhibitors. QSAR model was generated using 30 molecules in the training set; developed model showed good statistical reliability, which is evident from r 2 ncv and r 2 loo values. The predictive ability of this model was determined using a test set of 13 molecules that gave acceptable predictive correlation (r 2 Pred ) values. Finally, molecular dynamics simulation was performed to validate docking results and MM/GBSA calculations. This facilitated us to compare binding free energies of cocrystal ligand and newly designed molecule R1. The good concordance between the docking results and CoMFA/CoMSIA contour maps afforded obliging clues for the rational modification of molecules to design more potent JAK 1 inhibitors. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. A highly selective, orally active inhibitor of Janus kinase 2, CEP-33779, ablates disease in two mouse models of rheumatoid arthritis

    PubMed Central

    2011-01-01

    Introduction Janus kinase 2 (JAK2) is involved in the downstream activation of signal transducer and activator of transcription 3 (STAT3) and STAT5 and is responsible for transducing signals for several proinflammatory cytokines involved in the pathogenesis of rheumatoid arthritis (RA), including interleukin (IL)-6, interferon γ (IFNγ) and IL-12. In this paper, we describe the efficacy profile of CEP-33779, a highly selective, orally active, small-molecule inhibitor of JAK2 evaluated in two mouse models of RA. Methods Collagen antibody-induced arthritis (CAIA) and collagen type II (CII)-induced arthritis (CIA) were established before the oral administration of a small-molecule JAK2 inhibitor, CEP-33779, twice daily at 10 mg/kg, 30 mg/kg, 55 mg/kg or 100 mg/kg over a period of 4 to 8 weeks. Results Pharmacodynamic inhibition of JAK2 reduced mean paw edema and clinical scores in both CIA and CAIA models of arthritis. Reduction in paw cytokines (IL-12, IFNγ and tumor necrosis factor α) and serum cytokines (IL-12 and IL-2) correlated with reduced spleen CII-specific T helper 1 cell frequencies as measured by ex vivo IFNγ enzyme-linked immunosorbent spot assay. Both models demonstrated histological evidence of disease amelioration upon treatment (for example, reduced matrix erosion, subchondral osteolysis, pannus formation and synovial inflammation) and reduced paw phosphorylated STAT3 levels. No changes in body weight or serum anti-CII autoantibody titers were observed in either RA model. Conclusions This study demonstrates the utility of using a potent and highly selective, orally bioavailable JAK2 inhibitor for the treatment of RA. Using a selective inhibitor of JAK2 rather than pan-JAK inhibitors avoids the potential complication of immunosuppression while targeting critical signaling pathways involved in autoimmune disease progression. PMID:21510883

  7. Design and synthesis of carbazole carboxamides as promising inhibitors of Bruton’s tyrosine kinase (BTK) and Janus kinase 2 (JAK2)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Liu, Qingjie; Batt, Douglas G.; Lippy, Jonathan S.

    Four series of disubstituted carbazole-1-carboxamides were designed and synthesised as inhibitors of Bruton’s tyrosine kinase (BTK). 4,7- and 4,6-disubstituted carbazole-1-carboxamides were potent and selective inhibitors of BTK, while 3,7- and 3,6-disubstituted carbazole-1-carboxamides were potent and selective inhibitors of Janus kinase 2 (JAK2).

  8. Growth-hormone-induced signal transducer and activator of transcription 5 signaling causes gigantism, inflammation, and premature death but protects mice from aggressive liver cancer.

    PubMed

    Friedbichler, Katrin; Themanns, Madeleine; Mueller, Kristina M; Schlederer, Michaela; Kornfeld, Jan-Wilhelm; Terracciano, Luigi M; Kozlov, Andrey V; Haindl, Susanne; Kenner, Lukas; Kolbe, Thomas; Mueller, Mathias; Snibson, Kenneth J; Heim, Markus H; Moriggl, Richard

    2012-03-01

    Persistently high levels of growth hormone (GH) can cause liver cancer. GH activates multiple signal-transduction pathways, among them janus kinase (JAK) 2-signal transducer and activator of transcription (STAT) 5 (signal transducer and activator of transcription 5). Both hyperactivation and deletion of STAT5 in hepatocytes have been implicated in the development of hepatocellular carcinoma (HCC); nevertheless, the role of STAT5 in the development of HCC as a result of high GH levels remains enigmatic. Thus, we crossed a mouse model of gigantism and inflammatory liver cancer caused by hyperactivated GH signaling (GH(tg) ) to mice with hepatic deletion of STAT5 (STAT5(Δhep) ). Unlike GH(tg) mice, GH(tg) STAT5(Δhep) animals did not display gigantism. Moreover, the premature mortality, which was associated with chronic inflammation, as well as the pathologic alterations of hepatocytes observed in GH(tg) mice, were not observed in GH(tg) animals lacking STAT5. Strikingly, loss of hepatic STAT5 proteins led to enhanced HCC development in GH(tg) mice. Despite reduced chronic inflammation, GH(tg) STAT5(Δhep) mice displayed earlier and more advanced HCC than GH(tg) animals. This may be attributed to the combination of increased peripheral lipolysis, hepatic lipid synthesis, loss of hepatoprotective mediators accompanied by aberrant activation of tumor-promoting c-JUN and STAT3 signaling cascades, and accumulation of DNA damage secondary to loss of cell-cycle control. Thus, HCC was never observed in STAT5(Δhep) mice. As a result of their hepatoprotective functions, STAT5 proteins prevent progressive fatty liver disease and the formation of aggressive HCC in the setting of hyperactivated GH signaling. At the same time, they play a key role in controlling systemic inflammation and regulating organ and body size. Copyright © 2011 American Association for the Study of Liver Diseases.

  9. Update on Janus Kinase Antagonists in Inflammatory Bowel Disease

    PubMed Central

    Boland, Brigid S.; Sandborn, William J.; Chang, John T.

    2014-01-01

    Janus kinase (JAK) inhibitors have emerged as a novel orally administered small molecule therapy for the treatment of ulcerative colitis and possibly Crohn’s disease. These molecules are designed to selectively target the activity of specific JAKs and offer a targeted mechanism of action without risk of immunogenicity. Based on data from clinical trials in rheumatoid arthritis and phase 2 studies in inflammatory bowel disease, tofacitinib and other JAK inhibitors are likely to become a new form of medical therapy for the treatment of inflammatory bowel disease. PMID:25110261

  10. Signaling by STATs

    PubMed Central

    Ivashkiv, Lionel B; Hu, Xiaoyu

    2004-01-01

    A variety of cytokines and growth factors use the Janus kinase (Jak)–STAT signaling pathway to transmit extracellular signals to the nucleus. STATs (signal transducers and activators of transcription) are latent cytoplasmic transcription factors. There are seven mammalian STATs and they have critical, nonredundant roles in mediating cellular transcriptional responses to cytokines. The physiological roles of STATs have been elucidated by analysis of mice rendered deficient in STAT genes. STAT activation is regulated and can be modulated in a positive or negative fashion; it can be reprogrammed to drive different cellular responses. Several auto-regulatory and signaling crosstalk mechanisms for regulating Jak–STAT signaling have been described. Understanding and manipulation of the function of STATs will help in the development of therapeutic strategies for diseases that are regulated by cytokines. PMID:15225360

  11. Signaling by STATs.

    PubMed

    Ivashkiv, Lionel B; Hu, Xiaoyu

    2004-01-01

    A variety of cytokines and growth factors use the Janus kinase (Jak)-STAT signaling pathway to transmit extracellular signals to the nucleus. STATs (signal transducers and activators of transcription) are latent cytoplasmic transcription factors. There are seven mammalian STATs and they have critical, nonredundant roles in mediating cellular transcriptional responses to cytokines. The physiological roles of STATs have been elucidated by analysis of mice rendered deficient in STAT genes. STAT activation is regulated and can be modulated in a positive or negative fashion; it can be reprogrammed to drive different cellular responses. Several auto-regulatory and signaling crosstalk mechanisms for regulating Jak-STAT signaling have been described. Understanding and manipulation of the function of STATs will help in the development of therapeutic strategies for diseases that are regulated by cytokines.

  12. VX-509 (decernotinib) is a potent and selective janus kinase 3 inhibitor that attenuates inflammation in animal models of autoimmune disease.

    PubMed

    Mahajan, Sudipta; Hogan, James K; Shlyakhter, Dina; Oh, Luke; Salituro, Francesco G; Farmer, Luc; Hoock, Thomas C

    2015-05-01

    Cytokines, growth factors, and other chemical messengers rely on a class of intracellular nonreceptor tyrosine kinases known as Janus kinases (JAKs) to rapidly transduce intracellular signals. A number of these cytokines are critical for lymphocyte development and mediating immune responses. JAK3 is of particular interest due to its importance in immune function and its expression, which is largely confined to lymphocytes, thus limiting the potential impact of JAK3 inhibition on nonimmune physiology. The aim of this study was to evaluate the potency and selectivity of the investigational JAK3 inhibitor VX-509 (decernotinib) [(R)-2-((2-(1H-pyrrolo[2,3-b]pyridin-3-yl)pyrimidin-4-yl)amino)-2-methyl-N-(2,2,2-trifluoroethyl)butanamide] against JAK3 kinase activity and inhibition of JAK3-mediated signaling in vitro and JAK3-dependent physiologic processes in vivo. These results demonstrate that VX-509 potently inhibits JAK3 in enzyme assays (Ki = 2.5 nM + 0.7 nM) and cellular assays dependent on JAK3 activity (IC50 range, 50-170 nM), with limited or no measurable potency against other JAK isotypes or non-JAK kinases. VX-509 also showed activity in two animal models of aberrant immune function. VX-509 treatment resulted in dose-dependent reduction in ankle swelling and paw weight and improved paw histopathology scores in the rat collagen-induced arthritis model. In a mouse model of oxazolone-induced delayed-type hypersensitivity, VX-509 reduced the T cell-mediated inflammatory response in skin. These findings demonstrate that VX-509 is a selective and potent inhibitor of JAK3 in vitro and modulates proinflammatory response in models of immune-mediated diseases, such as collagen-induced arthritis and delayed-type hypersensitivity. The data support evaluation of VX-509 for treatment of patients with autoimmune and inflammatory diseases such as rheumatoid arthritis. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

  13. The rationale for Janus kinase inhibitors for the treatment of spondyloarthritis.

    PubMed

    Veale, Douglas J; McGonagle, Dennis; McInnes, Iain B; Krueger, James G; Ritchlin, Christopher T; Elewaut, Dirk; Kanik, Keith S; Hendrikx, Thijs; Berstein, Gabriel; Hodge, Jennifer; Telliez, Jean-Baptiste

    2018-04-03

    The pathogenesis of SpA is multifactorial and involves a range of immune cell types and cytokines, many of which utilize Janus kinase (JAK) pathways for signaling. In this review, we summarize the animal and pre-clinical data that have demonstrated the effects of JAK blockade on the underlying molecular mechanisms of SpA and provide a rationale for JAK inhibition for the treatment of SpA. We also review the available clinical trial data evaluating JAK inhibitors tofacitinib, baricitinib, peficitinib, filgotinib and upadacitinib in PsA, AS and related inflammatory diseases, which have demonstrated the efficacy of these agents across a range of SpA-associated disease manifestations. The available clinical trial data, supported by pre-clinical animal model studies demonstrate that JAK inhibition is a promising therapeutic strategy for the treatment of SpA and may offer the potential for improvements in multiple articular and extra-articular disease manifestations of PsA and AS.

  14. The Janus Kinase (JAK) FERM and SH2 Domains: Bringing Specificity to JAK-Receptor Interactions.

    PubMed

    Ferrao, Ryan; Lupardus, Patrick J

    2017-01-01

    The Janus kinases (JAKs) are non-receptor tyrosine kinases essential for signaling in response to cytokines and interferons and thereby control many essential functions in growth, development, and immune regulation. JAKs are unique among tyrosine kinases for their constitutive yet non-covalent association with class I and II cytokine receptors, which upon cytokine binding bring together two JAKs to create an active signaling complex. JAK association with cytokine receptors is facilitated by N-terminal FERM and SH2 domains, both of which are classical mediators of peptide interactions. Together, the JAK FERM and SH2 domains mediate a bipartite interaction with two distinct receptor peptide motifs, the proline-rich "Box1" and hydrophobic "Box2," which are present in the intracellular domain of cytokine receptors. While the general sidechain chemistry of Box1 and Box2 peptides is conserved between receptors, they share very weak primary sequence homology, making it impossible to posit why certain JAKs preferentially interact with and signal through specific subsets of cytokine receptors. Here, we review the structure and function of the JAK FERM and SH2 domains in light of several recent studies that reveal their atomic structure and elucidate interaction mechanisms with both the Box1 and Box2 receptor motifs. These crystal structures demonstrate how evolution has repurposed the JAK FERM and SH2 domains into a receptor-binding module that facilitates interactions with multiple receptors possessing diverse primary sequences.

  15. Janus Kinase Inhibitors for the Treatment of Rheumatoid Arthritis.

    PubMed

    Turan, Senir; Walker, Scot

    2017-11-01

    Rheumatoid arthritis (RA) is a disease where the immune system attacks the linings of the joints, resulting in joint pain, stiffness, swelling, and destruction. Although many products are available for the treatment of RA, limitations such as adverse reactions and tolerance greatly affect adherence. Many of the current biologic disease-modifying antirheumatic drugs on the market are injectables, leaving a void to be filled for a product that can be taken orally. The most advanced of these approaches, the Janus kinase (JAK) inhibitors, are oral drugs that have not only made a breakthrough in RA, but also other skin conditions.

  16. Perspectives for the use of structural information and chemical genetics to develop inhibitors of Janus kinases

    PubMed Central

    Haan, Claude; Behrmann, Iris; Haan, Serge

    2010-01-01

    Abstract Gain-of-function mutations in the genes encoding Janus kinases have been discovered in various haematologic diseases. Jaks are composed of a FERM domain, an SH2 domain, a pseudokinase domain and a kinase domain, and a complex interplay of the Jak domains is involved in regulation of catalytic activity and association to cytokine receptors. Most activating mutations are found in the pseudokinase domain. Here we present recently discovered mutations in the context of our structural models of the respective domains. We describe two structural hotspots in the pseudokinase domain of Jak2 that seem to be associated either to myeloproliferation or to lymphoblastic leukaemia, pointing at the involvement of distinct signalling complexes in these disease settings. The different domains of Jaks are discussed as potential drug targets. We present currently available inhibitors targeting Jaks and indicate structural differences in the kinase domains of the different Jaks that may be exploited in the development of specific inhibitors. Moreover, we discuss recent chemical genetic approaches which can be applied to Jaks to better understand the role of these kinases in their biological settings and as drug targets. PMID:20132407

  17. Multidisciplinary Analysis of Cyclophilin A Function in Human Breast Cancer

    DTIC Science & Technology

    2010-03-01

    between prolyl isomerases and cell surface receptors. Figure 1. Regulation of the prolactin receptor/Janus kinase 2 (PRLr...334 in the X-box motif of the PRLr; the red circle containing P indicates phosphorylation of JAK2 kinase , PRLr, and signal transducer and activator of...shares seven significant Janus homology domains (JH1-7) (from the C- to the N-terminus) to other members of the Jak kinase family as described below: (1

  18. The Janus kinase inhibitor tofacitinib inhibits TNF-α-induced gliostatin expression in rheumatoid fibroblast-like synoviocytes.

    PubMed

    Kawaguchi, Yohei; Waguri-Nagaya, Yuko; Tatematsu, Naoe; Oguri, Yusuke; Kobayashi, Masaaki; Nozaki, Masahiro; Asai, Kiyofumi; Aoyama, Mineyoshi; Otsuka, Takanobu

    2018-01-15

    Gliostatin (GLS) is known to have angiogenic and arthritogenic activity, and GLS expression levels in serum from patients with rheumatoid arthritis (RA) are significantly correlated with the disease activity. Tofacitinib is a novel oral Janus kinase (JAK) inhibitor and is effective in treating RA. However, the mechanism of action of tofacitinib in fibroblast-like synoviocytes (FLSs) has not been elucidated. The purpose of this study was to investigate the modulatory effects of tofacitinib on serum GLS levels in patients with RA and GLS production in FLSs derived from patients with RA. Six patients with RA who had failed therapy with at least one TNF inhibitor and were receiving tofacitinib therapy were included in the study. Serum samples were collected to measure CRP, MMP-3 and GLS expression. FLSs derived from patients with RA were cultured and stimulated by TNFα with or without tofacitinib. GLS expression levels were determined using reverse transcription-polymerase chain reaction (RT-PCR), EIA and immunocytochemistry, and signal transducer and activator of transcription (STAT) protein phosphorylation levels were determined by western blotting. Treatment with tofacitinib decreased serum GLS levels in all patients. GLS mRNA and protein expression levels were significantly increased by treatment with TNF-α alone, and these increases were suppressed by treatment with tofacitinib, which also inhibited TNF-α-induced STAT1 phosphorylation. JAK/STAT activation plays a pivotal role in TNF-α-mediated GLS up-regulation in RA. Suppression of GLS expression in FLSs has been suggested to be one of the mechanisms through which tofacitinib exerts its anti-inflammatory effects.

  19. Treatment of vitiligo with the topical Janus kinase inhibitor ruxolitinib.

    PubMed

    Rothstein, Brooke; Joshipura, Deep; Saraiya, Ami; Abdat, Rana; Ashkar, Huda; Turkowski, Yana; Sheth, Vaneeta; Huang, Victor; Au, Shiu Chung; Kachuk, Courtney; Dumont, Nicole; Gottlieb, Alice B; Rosmarin, David

    2017-06-01

    Existing therapies for vitiligo are limited in efficacy and can be associated with undesirable side effects. Topical Janus kinase inhibitors may offer a new therapeutic option for vitiligo. We sought to assess the role of topical ruxolitinib 1.5% cream, a Janus kinase inhibitor, in vitiligo treatment. This 20-week, open-label, proof-of-concept trial of twice-daily topical ruxolitinib 1.5% cream was conducted in 12 patients with a minimum of 1% affected body surface area of vitiligo. The primary outcome was percent improvement in Vitiligo Area Scoring Index from baseline to week 20. Of 12 patients screened, 11 were enrolled and 9 completed the study (54.5% men; mean age, 52 years). Four patients with significant facial involvement at baseline had a 76% improvement in facial Vitiligo Area Scoring Index scores at week 20 (95% confidence interval, 53-99%; P = .001). A 23% improvement in overall Vitiligo Area Scoring Index scores was observed in all enrolled patients at week 20 (95% confidence interval, 4-43%; P = .02). Three of 8 patients responded on body surfaces and 1 of 8 patients responded on acral surfaces. Adverse events were minor, including erythema, hyperpigmentation, and transient acne. Limitations of the study include the small sample size and open-label study design. Topical ruxolitinib 1.5% cream provided significant repigmentation in facial vitiligo and may offer a valuable new treatment for vitiligo. Copyright © 2017 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  20. Roles of STATs signaling in cardiovascular diseases.

    PubMed

    Kishore, Raj; Verma, Suresh K

    2012-04-01

    In cardiac and many other systems, chronic stress activates avfamily of structurally and functionally conserved receptors and their downstream signaling molecules that entail tyrosine, serine or threonine phosphorylation to transfer the messages to the genetic machinery. However, the activation of the Janus kinases (JAKs) and their downstream signal transducer and activator of transcription (STATs) proteins is both characteristic of and unique to cytokine and growth factor signaling which plays a central role in heart physiology. Dysregulation of JAK-STAT signaling is associated with various cardiovascular diseases. The molecular signaling and specificity of the JAK-STAT pathway are modulated at many levels by distinct regulatory proteins. Here, we review recent studies on the regulation of the STAT signaling pathway that will enhance our ability to design rational therapeutic strategies for stress-induced heart failure.

  1. Effects of Human Mesenchymal Stem Cells Transduced with Superoxide Dismutase on Imiquimod-Induced Psoriasis-Like Skin Inflammation in Mice.

    PubMed

    Sah, Shyam Kishor; Park, Kyung Ho; Yun, Chae-Ok; Kang, Kyung-Sun; Kim, Tae-Yoon

    2016-02-10

    The immunomodulatory and anti-inflammatory properties of mesenchymal stem cells (MSCs) have been proposed in several autoimmune diseases and successfully tested in animal models, but their contribution to psoriasis and underlying pathways remains elusive. Likewise, an increased or prolonged presence of reactive oxygen species and aberrant antioxidant systems in skin are known to contribute to the development of psoriasis and therefore effective antioxidant therapy is highly required. We explored the feasibility of using extracellular superoxide dismutase (SOD3)-transduced allogeneic MSCs as a novel therapeutic approach in a mouse model of imiquimod (IMQ)-induced psoriasis-like inflammation and investigated the poorly understood underlying mechanism. In addition, the chronicity and late-phase response of inflammation were evaluated during continued activation of antigen receptors by applying a booster dose of IMQ. Subcutaneous injection of allogeneic SOD3-transduced MSCs significantly prevented psoriasis development in our IMQ-induced mouse model, likely through a suppression of proliferation and infiltration of various effector cells into skin with a concomitant modulated cytokine and chemokine expression and inhibition of signaling pathways such as toll-like receptor-7, nuclear factor-kappa B, p38 mitogen-activated kinase, and Janus kinase-signal transducer and activator of transcription, as well as adenosine receptor activation. Our data offer a novel therapeutic approach to chronic inflammatory skin diseases such as psoriasis by leveraging immunomodulatory effects of MSCs as well as SOD3 expression.

  2. Angiotensin II mediated signal transduction. Important role of tyrosine kinases.

    PubMed

    Haendeler, J; Berk, B C

    2000-11-24

    It has been 100 years since the discovery of renin by Bergman and Tigerstedt. Since then, numerous studies have advanced our understanding of the renin-angiotensin system. A remarkable aspect was the discovery that angiotensin II (AngII) is the central product of the renin-angiotensin system and that this octapeptide induces multiple physiological responses in different cell types. In addition to its well known vasoconstrictive effects, growing evidence supports the notion that AngII may play a central role not only in hypertension, but also in cardiovascular and renal diseases. Binding of AngII to the seven-transmembrane angiotensin II type 1 receptor is responsible for nearly all of the physiological actions of AngII. Recent studies underscore the new concept that activation of intracellular second messengers by AngII requires tyrosine phosphorylation. An increasing number of tyrosine kinases have been shown to be activated by AngII, including the Src kinase family, the focal adhesion kinase family, the Janus kinases and receptor tyrosine kinases. These actions of AngII contribute to the pathophysiology of cardiac hypertrophy and remodeling, vascular thickening, heart failure and atherosclerosis. In this review, we discuss the important role of tyrosine kinases in AngII-mediated signal transduction. Understanding the importance of tyrosine phosphorylation in AngII-stimulated signaling events may contribute to new therapies for cardiovascular and renal diseases.

  3. The Roles of NDR Protein Kinases in Hippo Signalling.

    PubMed

    Hergovich, Alexander

    2016-05-18

    The Hippo tumour suppressor pathway has emerged as a critical regulator of tissue growth through controlling cellular processes such as cell proliferation, death, differentiation and stemness. Traditionally, the core cassette of the Hippo pathway includes the MST1/2 protein kinases, the LATS1/2 protein kinases, and the MOB1 scaffold signal transducer, which together regulate the transcriptional co-activator functions of the proto-oncoproteins YAP and TAZ through LATS1/2-mediated phosphorylation of YAP/TAZ. Recent research has identified additional kinases, such as NDR1/2 (also known as STK38/STK38L) and MAP4Ks, which should be considered as novel members of the Hippo core cassette. While these efforts helped to expand our understanding of Hippo core signalling, they also began to provide insights into the complexity and redundancy of the Hippo signalling network. Here, we focus on summarising our current knowledge of the regulation and functions of mammalian NDR kinases, discussing parallels between the NDR pathways in Drosophila and mammals. Initially, we provide a general overview of the cellular functions of NDR kinases in cell cycle progression, centrosome biology, apoptosis, autophagy, DNA damage signalling, immunology and neurobiology. Finally, we put particular emphasis on discussing NDR1/2 as YAP kinases downstream of MST1/2 and MOB1 signalling in Hippo signalling.

  4. The Role of Stat3 Activation in Androgen Receptor Signaling and Prostate Cancer

    DTIC Science & Technology

    2005-07-01

    METHODS InVitro Growth Assay Tissue Culture DU145, PC3, and LN-17 cells ( 1 x 105 per well) were plated in 12-well plates in RPMI containing 10% FBS. Human...specific ELISA kit. 1 ] LNSI Parental LNCaP, neo, and IL- # OLN-S17 6 overexpressing (LN-S15 c 0.8 - and LN-S17) cells were 0e cultured in either...independence [1,2]. Stat3, a member of Janus Shadyside Medical Center, Suite G03, 5200 Centre Avenue, Kinase (JAK)-Signal Transducers and Activators of

  5. The prognostic impact of germline 46/1 haplotype of Janus kinase 2 in cytogenetically normal acute myeloid leukemia

    PubMed Central

    Nahajevszky, Sarolta; Andrikovics, Hajnalka; Batai, Arpad; Adam, Emma; Bors, Andras; Csomor, Judit; Gopcsa, Laszlo; Koszarska, Magdalena; Kozma, Andras; Lovas, Nora; Lueff, Sandor; Matrai, Zoltan; Meggyesi, Nora; Sinko, Janos; Sipos, Andrea; Varkonyi, Andrea; Fekete, Sandor; Tordai, Attila; Masszi, Tamas

    2011-01-01

    Background Prognostic risk stratification according to acquired or inherited genetic alterations has received increasing attention in acute myeloid leukemia in recent years. A germline Janus kinase 2 haplotype designated as the 46/1 haplotype has been reported to be associated with an inherited predisposition to myeloproliferative neoplasms, and also to acute myeloid leukemia with normal karyotype. The aim of this study was to assess the prognostic impact of the 46/1 haplotype on disease characteristics and treatment outcome in acute myeloid leukemia. Design and Methods Janus kinase 2 rs12343867 single nucleotide polymorphism tagging the 46/1 haplotype was genotyped by LightCycler technology applying melting curve analysis with the hybridization probe detection format in 176 patients with acute myeloid leukemia under 60 years diagnosed consecutively and treated with curative intent. Results The morphological subtype of acute myeloid leukemia with maturation was less frequent among 46/1 carriers than among non-carriers (5.6% versus 17.2%, P=0.018, cytogenetically normal subgroup: 4.3% versus 20.6%, P=0.031), while the morphological distribution shifted towards the myelomonocytoid form in 46/1 haplotype carriers (28.1% versus 14.9%, P=0.044, cytogenetically normal subgroup: 34.0% versus 11.8%, P=0.035). In cytogenetically normal cases of acute myeloid leukemia, the 46/1 carriers had a considerably lower remission rate (78.7% versus 94.1%, P=0.064) and more deaths in remission or in aplasia caused by infections (46.8% versus 23.5%, P=0.038), resulting in the 46/1 carriers having shorter disease-free survival and overall survival compared to the 46/1 non-carriers. In multivariate analysis, the 46/1 haplotype was an independent adverse prognostic factor for disease-free survival (P=0.024) and overall survival (P=0.024) in patients with a normal karyotype. Janus kinase 2 46/1 haplotype had no impact on prognosis in the subgroup with abnormal karyotype. Conclusions Janus

  6. A Review of Fabry Disease.

    PubMed

    Cinats, A; Heck, E

    2018-05-01

    The class of medications known as Janus kinase inhibitors block cytokine-mediated signaling via the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway, which plays an important role in immunoregulation and normal cell growth. This class includes the drugs tofacitinib, approved for the treatment of rheumatoid arthritis, and ruxolitinib, approved for the treatment of myelofibrosis and polycythemia rubra vera. The most common adverse events (AEs) reported in patients taking tofacitinib are infections, whereas the most common AEs in patients taking ruxolitinib are anemia and thrombocytopenia. Both first and second generation Janus kinase inhibitors have become promising treatment modalities for dermatologic conditions such as psoriasis, atopic dermatitis, alopecia areata, vilitigo, dermatomyositis, and graft-versus-host disease. Future promising areas of investigation include treatment of cutaneous lupus, cutaneous T-cell lymphoma, melanoma, allergic contact dermatitis, and lichen planus.

  7. Identification of signalling cascades involved in red blood cell shrinkage and vesiculation.

    PubMed

    Kostova, Elena B; Beuger, Boukje M; Klei, Thomas R L; Halonen, Pasi; Lieftink, Cor; Beijersbergen, Roderick; van den Berg, Timo K; van Bruggen, Robin

    2015-04-16

    Even though red blood cell (RBC) vesiculation is a well-documented phenomenon, notably in the context of RBC aging and blood transfusion, the exact signalling pathways and kinases involved in this process remain largely unknown. We have established a screening method for RBC vesicle shedding using the Ca(2+) ionophore ionomycin which is a rapid and efficient method to promote vesiculation. In order to identify novel pathways stimulating vesiculation in RBC, we screened two libraries: the Library of Pharmacologically Active Compounds (LOPAC) and the Selleckchem Kinase Inhibitor Library for their effects on RBC from healthy donors. We investigated compounds triggering vesiculation and compounds inhibiting vesiculation induced by ionomycin. We identified 12 LOPAC compounds, nine kinase inhibitors and one kinase activator which induced RBC shrinkage and vesiculation. Thus, we discovered several novel pathways involved in vesiculation including G protein-coupled receptor (GPCR) signalling, the phosphoinositide 3-kinase (PI3K)-Akt (protein kinase B) pathway, the Jak-STAT (Janus kinase-signal transducer and activator of transcription) pathway and the Raf-MEK (mitogen-activated protein kinase kinase)-ERK (extracellular signal-regulated kinase) pathway. Moreover, we demonstrated a link between casein kinase 2 (CK2) and RBC shrinkage via regulation of the Gardos channel activity. In addition, our data showed that inhibition of several kinases with unknown functions in mature RBC, including Alk (anaplastic lymphoma kinase) kinase and vascular endothelial growth factor receptor 2 (VEGFR-2), induced RBC shrinkage and vesiculation.

  8. Identification of signalling cascades involved in red blood cell shrinkage and vesiculation

    PubMed Central

    Kostova, Elena B.; Beuger, Boukje M.; Klei, Thomas R.L.; Halonen, Pasi; Lieftink, Cor; Beijersbergen, Roderick; van den Berg, Timo K.; van Bruggen, Robin

    2015-01-01

    Even though red blood cell (RBC) vesiculation is a well-documented phenomenon, notably in the context of RBC aging and blood transfusion, the exact signalling pathways and kinases involved in this process remain largely unknown. We have established a screening method for RBC vesicle shedding using the Ca2+ ionophore ionomycin which is a rapid and efficient method to promote vesiculation. In order to identify novel pathways stimulating vesiculation in RBC, we screened two libraries: the Library of Pharmacologically Active Compounds (LOPAC) and the Selleckchem Kinase Inhibitor Library for their effects on RBC from healthy donors. We investigated compounds triggering vesiculation and compounds inhibiting vesiculation induced by ionomycin. We identified 12 LOPAC compounds, nine kinase inhibitors and one kinase activator which induced RBC shrinkage and vesiculation. Thus, we discovered several novel pathways involved in vesiculation including G protein-coupled receptor (GPCR) signalling, the phosphoinositide 3-kinase (PI3K)–Akt (protein kinase B) pathway, the Jak–STAT (Janus kinase–signal transducer and activator of transcription) pathway and the Raf–MEK (mitogen-activated protein kinase kinase)–ERK (extracellular signal-regulated kinase) pathway. Moreover, we demonstrated a link between casein kinase 2 (CK2) and RBC shrinkage via regulation of the Gardos channel activity. In addition, our data showed that inhibition of several kinases with unknown functions in mature RBC, including Alk (anaplastic lymphoma kinase) kinase and vascular endothelial growth factor receptor 2 (VEGFR-2), induced RBC shrinkage and vesiculation. PMID:25757360

  9. Signal transducers and activators of transcription: STATs-mediated mitochondrial neuroprotection.

    PubMed

    Lin, Hung Wen; Thompson, John W; Morris, Kahlilia C; Perez-Pinzon, Miguel A

    2011-05-15

    Cerebral ischemia is defined as little or no blood flow in cerebral circulation, characterized by low tissue oxygen and glucose levels, which promotes neuronal mitochondria dysfunction leading to cell death. A strategy to counteract cerebral ischemia-induced neuronal cell death is ischemic preconditioning (IPC). IPC results in neuroprotection, which is conferred by a mild ischemic challenge prior to a normally lethal ischemic insult. Although many IPC-induced mechanisms have been described, many cellular and subcellular mechanisms remain undefined. Some reports have suggested key signal transduction pathways of IPC, such as activation of protein kinase C epsilon, mitogen-activated protein kinase, and hypoxia-inducible factors, that are likely involved in IPC-induced mitochondria mediated-neuroprotection. Moreover, recent findings suggest that signal transducers and activators of transcription (STATs), a family of transcription factors involved in many cellular activities, may be intimately involved in IPC-induced ischemic tolerance. In this review, we explore current signal transduction pathways involved in IPC-induced mitochondria mediated-neuroprotection, STAT activation in the mitochondria as it relates to IPC, and functional significance of STATs in cerebral ischemia.

  10. The Growth Hormone Receptor: Mechanism of Receptor Activation, Cell Signaling, and Physiological Aspects

    PubMed Central

    Dehkhoda, Farhad; Lee, Christine M. M.; Medina, Johan; Brooks, Andrew J.

    2018-01-01

    The growth hormone receptor (GHR), although most well known for regulating growth, has many other important biological functions including regulating metabolism and controlling physiological processes related to the hepatobiliary, cardiovascular, renal, gastrointestinal, and reproductive systems. In addition, growth hormone signaling is an important regulator of aging and plays a significant role in cancer development. Growth hormone activates the Janus kinase (JAK)–signal transducer and activator of transcription (STAT) signaling pathway, and recent studies have provided a new understanding of the mechanism of JAK2 activation by growth hormone binding to its receptor. JAK2 activation is required for growth hormone-mediated activation of STAT1, STAT3, and STAT5, and the negative regulation of JAK–STAT signaling comprises an important step in the control of this signaling pathway. The GHR also activates the Src family kinase signaling pathway independent of JAK2. This review covers the molecular mechanisms of GHR activation and signal transduction as well as the physiological consequences of growth hormone signaling. PMID:29487568

  11. Signal Transducers and Activators of Transcription: STATs-Mediated Mitochondrial Neuroprotection

    PubMed Central

    Lin, Hung Wen; Thompson, John W.; Morris, Kahlilia C.

    2011-01-01

    Abstract Cerebral ischemia is defined as little or no blood flow in cerebral circulation, characterized by low tissue oxygen and glucose levels, which promotes neuronal mitochondria dysfunction leading to cell death. A strategy to counteract cerebral ischemia-induced neuronal cell death is ischemic preconditioning (IPC). IPC results in neuroprotection, which is conferred by a mild ischemic challenge prior to a normally lethal ischemic insult. Although many IPC-induced mechanisms have been described, many cellular and subcellular mechanisms remain undefined. Some reports have suggested key signal transduction pathways of IPC, such as activation of protein kinase C epsilon, mitogen-activated protein kinase, and hypoxia-inducible factors, that are likely involved in IPC-induced mitochondria mediated-neuroprotection. Moreover, recent findings suggest that signal transducers and activators of transcription (STATs), a family of transcription factors involved in many cellular activities, may be intimately involved in IPC-induced ischemic tolerance. In this review, we explore current signal transduction pathways involved in IPC-induced mitochondria mediated-neuroprotection, STAT activation in the mitochondria as it relates to IPC, and functional significance of STATs in cerebral ischemia. Antioxid. Redox Signal. 14, 1853–1861. PMID:20712401

  12. Deletion of Interleukin-6 Signal Transducer gp130 in Small Sensory Neurons Attenuates Mechanonociception and Down-Regulates TRPA1 Expression

    PubMed Central

    Malsch, Philipp; Andratsch, Manfred; Vogl, Christian; Link, Andrea S.; Alzheimer, Christian; Brierley, Stuart M.; Hughes, Patrick A.

    2014-01-01

    Glycoprotein 130 (gp130) is the signal transducing receptor subunit for cytokines of the interleukin-6 (IL-6) family, and it is expressed in a multitude of cell types of the immune and nervous system. IL-6-like cytokines are not only key regulators of innate immunity and inflammation but are also essential factors for the differentiation and development of the somatosensory system. Mice with a null mutation of gp130 in primary nociceptive afferents (SNS-gp130−/−) are largely protected from hypersensitivity to mechanical stimuli in mouse models of pathological pain. Therefore, we set out to investigate how neuronal gp130 regulates mechanonociception. SNS-gp130−/− mice revealed reduced mechanosensitivity to high mechanical forces in the von Frey assay in vivo, and this was associated with a reduced sensitivity of nociceptive primary afferents in vitro. Together with these findings, transient receptor potential ankyrin 1 (TRPA1) mRNA expression was significantly reduced in DRG from SNS-gp130−/− mice. This was also reflected by a reduced number of neurons responding with calcium transients to TRPA1 agonists in primary DRG cultures. Downregulation of Trpa1 expression was predominantly discovered in nonpeptidergic neurons, with the deficit becoming evident during stages of early postnatal development. Regulation of Trpa1 mRNA expression levels downstream of gp130 involved the classical Janus kinase family-signal transducer and activator of transcription pathway. Our results closely link proinflammatory cytokines to the expression of TRPA1, both of which have been shown to contribute to hypersensitive pain states. We suggest that gp130 has an essential role in mechanonociception and in the regulation of TRPA1 expression. PMID:25057188

  13. Janus Kinase Antagonists and Other Novel Small Molecules for the Treatment of Crohn's Disease.

    PubMed

    Boland, Brigid S; Vermeire, Séverine

    2017-09-01

    There is an ongoing, unmet need for effective therapies for Crohn's disease. Treatments for Crohn's disease continue to evolve from the traditional biologics to novel small molecules, with targeted mechanisms directed toward pathways that are dysregulated in Crohn's disease. There are multiple emerging mechanisms of action, including Janus kinase inhibition, Smad7 inhibition, and sphingosine-1-phosphate receptor modulators, that are administered as oral medications, and small molecules represent the next generation of therapies for Crohn's disease. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. A Review: Phytochemicals Targeting JAK/STAT Signaling and IDO Expression in Cancer.

    PubMed

    Arumuggam, Niroshaathevi; Bhowmick, Neil A; Rupasinghe, H P Vasantha

    2015-06-01

    Cancer remains a major health problem worldwide. Among many other factors, two regulatory defects that are present in most cancer cells are constitutive activation of Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathway and the induction of indoleamine 2, 3-dioxygenase (IDO), an enzyme that catalyzes tryptophan degradation, through JAK/STAT signaling. Cytokine signaling activates STAT proteins in regulating cell proliferation, differentiation, and survival through modulation of target genes. Many phytochemicals can inhibit both JAK/STAT signaling and IDO expression in antigen-presenting cells by targeting different pathways. Some of the promising phytochemicals that are discussed in this review include resveratrol, cucurbitacin, curcumin, (-)-epigallocatechin gallate, and others. It is now evident that phytochemicals play key roles in inhibition of tumor proliferation and development and provide novel means for therapeutic targeting of cancer. Copyright © 2015 John Wiley & Sons, Ltd.

  15. The GHR mutations related to individual’s dwarf

    USDA-ARS?s Scientific Manuscript database

    Growth hormone (GH) promotes body’s growth through binding with two receptors (GHRs) at the cell surface to interact with Janus kinase and signal transducers and activators of transcription, and then to stimulate metabolic effects and insulin-like growth factor (IGF) synthesis. However, the disorder...

  16. Temporal quantitation of mutant Kit tyrosine kinase signaling attenuated by a novel thiophene kinase inhibitor OSI-930.

    PubMed

    Petti, Filippo; Thelemann, April; Kahler, Jen; McCormack, Siobhan; Castaldo, Linda; Hunt, Tony; Nuwaysir, Lydia; Zeiske, Lynn; Haack, Herbert; Sullivan, Laura; Garton, Andrew; Haley, John D

    2005-08-01

    OSI-930, a potent thiophene inhibitor of the Kit, KDR, and platelet-derived growth factor receptor tyrosine kinases, was used to selectively inhibit tyrosine phosphorylation downstream of juxtamembrane mutant Kit in the mast cell leukemia line HMC-1. Inhibition of Kit kinase activity resulted in a rapid dephosphorylation of Kit and inhibition of the downstream signaling pathways. Attenuation of Ras-Raf-Erk (phospho-Erk, phospho-p38), phosphatidyl inositol-3' kinase (phospho-p85, phospho-Akt, phospho-S6), and signal transducers and activators of transcription signaling pathways (phospho-STAT3/5/6) were measured by affinity liquid chromatography tandem mass spectrometry, by immunoblot, and by tissue microarrays of fixed cell pellets. To more globally define additional components of Kit signaling temporally altered by kinase inhibition, a novel multiplex quantitative isobaric peptide labeling approach was used. This approach allowed clustering of proteins by temporal expression patterns. Kit kinase, which dephosphorylates rapidly upon kinase inhibition, was shown to regulate both Shp-1 and BDP-1 tyrosine phosphatases and the phosphatase-interacting protein PSTPIP2. Interactions with SH2 domain adapters [growth factor receptor binding protein 2 (Grb2), Cbl, Slp-76] and SH3 domain adapters (HS1, cortactin, CD2BP3) were attenuated by inhibition of Kit kinase activity. Functional crosstalk between Kit and the non-receptor tyrosine kinases Fes/Fps, Fer, Btk, and Syk was observed. Inhibition of Kit modulated phosphorylation-dependent interactions with pathways controlling focal adhesion (paxillin, leupaxin, p130CAS, FAK1, the Src family kinase Lyn, Wasp, Fhl-3, G25K, Ack-1, Nap1, SH3P12/ponsin) and septin-actin complexes (NEDD5, cdc11, actin). The combined use of isobaric protein quantitation and expression clustering, immunoblot, and tissue microarray strategies allowed temporal measurement signaling pathways modulated by mutant Kit inhibition in a model of mast cell

  17. SAD kinases sculpt axonal arbors of sensory neurons through long and short-term responses to neurotrophin signals

    PubMed Central

    Lilley, Brendan N.; Pan, Y. Albert; Sanes, Joshua R.

    2013-01-01

    SUMMARY Extrinsic cues activate intrinsic signaling mechanisms to pattern neuronal shape and connectivity. We showed previously that three cytoplasmic Ser/Thr kinases, LKB1, SAD-A and SAD-B, control early axon-dendrite polarization in forebrain neurons. Here we assess their role in other neuronal types. We found that all three kinases are dispensable for axon formation outside of the cortex, but that SAD kinases are required for formation of central axonal arbors by subsets of sensory neurons. The requirement for SAD kinases is most prominent in NT-3 dependent neurons. SAD kinases transduce NT-3 signals in two ways through distinct pathways. First, sustained NT-3/TrkC signaling increases SAD protein levels. Second, short duration NT-3/TrkC signals transiently activate SADs by inducing dephosphorylation of C-terminal domains, thereby allowing activating phosphorylation of the kinase domain. We propose that SAD kinases integrate long- and short duration signals from extrinsic cues to sculpt axon arbors within the CNS. PMID:23790753

  18. β-arrestin drives MAP kinase signaling from clathrin-coated structures after GPCR dissociation

    PubMed Central

    Eichel, K.; Jullié, D.

    2016-01-01

    β-arrestins critically regulate G protein-coupled receptor (GPCR) signaling, not only 'arresting' the G protein signal but also modulating endocytosis and initiating a discrete G protein-independent signal via MAP kinase1–3. Despite enormous recent progress toward understanding biophysical aspects of arrestin function4,5, its cell biology remains relatively poorly understood. Two key tenets underlie the present dogma: (1) β-arrestin accumulates in clathrin-coated structures (CCSs) exclusively in physical complex with its activating GPCR, and (2) MAP kinase activation requires endocytosis of formed GPCR - β-arrestin complexes6–9. We show here, using β1-adrenergic receptors, that β-arrestin-2 (Arrestin 3) accumulates robustly in CCSs after dissociating from its activating GPCR and transduces the MAP kinase signal from CCSs. Moreover, inhibiting subsequent endocytosis of CCSs enhances the clathrin and β-arrestin -dependent MAP kinase signal. These results demonstrate β-arrestin 'activation at a distance', after dissociating from its activating GPCR, and signaling from CCSs. We propose a β-arrestin signaling cycle that is catalytically activated by the GPCR and energetically coupled to the endocytic machinery. PMID:26829388

  19. Single blastomere removal from murine embryos is associated with activation of matrix metalloproteinases and Janus kinase/signal transducers and activators of transcription pathways of placental inflammation

    PubMed Central

    Sato, Brittany L.M.; Sugawara, Atsushi; Ward, Monika A.; Collier, Abby C.

    2014-01-01

    Single blastomere removal from cleavage-stage embryos, a common procedure used in conjunction with preimplantation genetic diagnosis (PGD), may affect reproductive outcomes. We hypothesized that negative pregnancy outcomes associated with PGD may be due to impairment of placental signaling pathways. The goal of this study was to determine the molecular mechanisms through which placental signaling is deregulated by blastomere removal. Four-cell stage murine embryos produced by in vitro fertilization were subjected to removal of a single blastomere (biopsied) or to the same manipulations without the blastomere removal (controls). Placental tissues from term (18.5 day) pregnancies obtained after embryo transfer were tested for levels of nitrosative species, interleukin 6, signal transducers and activators of transcription (STAT) 1 and 3, suppressors of cytokine signaling (SOCS) 1, 2 and 3 and matrix metalloproteinases (MMP) 1, 2, 3 and 9. Significant increases in nitrosative stress (P < 0.05), phosphorylative activation of STAT1 (P < 0.05) but not STAT3, lower levels of the inhibitors SOCS2 (P < 0.01) and SOCS3 (P < 0.001) and activation of MMP9 (P < 0.001) were observed in placentas derived from biopsied embryos, compared with controls. Such effects could contribute to greater levels of premature membrane rupture, incorrect parturition, preterm birth and intrauterine growth restriction associated with PGD. This work has determined signaling mechanisms that may be responsible for blastomere removal effects on placental function, with the potential to become targets for improving obstetric and neonatal outcomes in assisted reproduction. PMID:25180268

  20. Novel mutations in the inhibitory adaptor protein LNK drive JAK-STAT signaling in patients with myeloproliferative neoplasms

    PubMed Central

    Oh, Stephen T.; Simonds, Erin F.; Jones, Carol; Hale, Matthew B.; Goltsev, Yury; Gibbs, Kenneth D.; Merker, Jason D.; Zehnder, James L.; Nolan, Garry P.

    2010-01-01

    Dysregulated Janus kinase–signal transducer and activator of transcription (JAK-STAT) signaling due to activation of tyrosine kinases is a common feature of myeloid malignancies. Here we report the first human disease-related mutations in the adaptor protein LNK, a negative regulator of JAK-STAT signaling, in 2 patients with JAK2 V617F–negative myeloproliferative neoplasms (MPNs). One patient exhibited a 5 base-pair deletion and missense mutation leading to a premature stop codon and loss of the pleckstrin homology (PH) and Src homology 2 (SH2) domains. A second patient had a missense mutation (E208Q) in the PH domain. BaF3-MPL cells transduced with these LNK mutants displayed augmented and sustained thrombopoietin-dependent growth and signaling. Primary samples from MPN patients bearing LNK mutations exhibited aberrant JAK-STAT activation, and cytokine-responsive CD34+ early progenitors were abnormally abundant in both patients. These findings indicate that JAK-STAT activation due to loss of LNK negative feedback regulation is a novel mechanism of MPN pathogenesis. PMID:20404132

  1. OsBRI1 Activates BR Signaling by Preventing Binding between the TPR and Kinase Domains of OsBSK3 via Phosphorylation.

    PubMed

    Zhang, Baowen; Wang, Xiaolong; Zhao, Zhiying; Wang, Ruiju; Huang, Xiahe; Zhu, Yali; Yuan, Li; Wang, Yingchun; Xu, Xiaodong; Burlingame, Alma L; Gao, Yingjie; Sun, Yu; Tang, Wenqiang

    2016-02-01

    Many plant receptor kinases transduce signals through receptor-like cytoplasmic kinases (RLCKs); however, the molecular mechanisms that create an effective on-off switch are unknown. The receptor kinase BR INSENSITIVE1 (BRI1) transduces brassinosteroid (BR) signal by phosphorylating members of the BR-signaling kinase (BSK) family of RLCKs, which contain a kinase domain and a C-terminal tetratricopeptide repeat (TPR) domain. Here, we show that the BR signaling function of BSKs is conserved in Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) and that the TPR domain of BSKs functions as a "phospho-switchable" autoregulatory domain to control BSKs' activity. Genetic studies revealed that OsBSK3 is a positive regulator of BR signaling in rice, while in vivo and in vitro assays demonstrated that OsBRI1 interacts directly with and phosphorylates OsBSK3. The TPR domain of OsBSK3, which interacts directly with the protein's kinase domain, serves as an autoinhibitory domain to prevent OsBSK3 from interacting with bri1-SUPPRESSOR1 (BSU1). Phosphorylation of OsBSK3 by OsBRI1 disrupts the interaction between its TPR and kinase domains, thereby increasing the binding between OsBSK3's kinase domain and BSU1. Our results not only demonstrate that OsBSK3 plays a conserved role in regulating BR signaling in rice, but also provide insight into the molecular mechanism by which BSK family proteins are inhibited under basal conditions but switched on by the upstream receptor kinase BRI1. © 2016 American Society of Plant Biologists. All Rights Reserved.

  2. SAD kinases sculpt axonal arbors of sensory neurons through long- and short-term responses to neurotrophin signals.

    PubMed

    Lilley, Brendan N; Pan, Y Albert; Sanes, Joshua R

    2013-07-10

    Extrinsic cues activate intrinsic signaling mechanisms to pattern neuronal shape and connectivity. We showed previously that three cytoplasmic Ser/Thr kinases, LKB1, SAD-A, and SAD-B, control early axon-dendrite polarization in forebrain neurons. Here, we assess their role in other neuronal types. We found that all three kinases are dispensable for axon formation outside of the cortex but that SAD kinases are required for formation of central axonal arbors by subsets of sensory neurons. The requirement for SAD kinases is most prominent in NT-3 dependent neurons. SAD kinases transduce NT-3 signals in two ways through distinct pathways. First, sustained NT-3/TrkC signaling increases SAD protein levels. Second, short-duration NT-3/TrkC signals transiently activate SADs by inducing dephosphorylation of C-terminal domains, thereby allowing activating phosphorylation of the kinase domain. We propose that SAD kinases integrate long- and short-duration signals from extrinsic cues to sculpt axon arbors within the CNS. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. The stem cell factor (SCF)/c-KIT signalling in testis and prostate cancer.

    PubMed

    Cardoso, Henrique J; Figueira, Marília I; Socorro, Sílvia

    2017-12-01

    The stem cell factor (SCF) is a cytokine that specifically binds the tyrosine kinase receptor c-KIT. The SCF/c-KIT interaction leads to receptor dimerization, activation of kinase activity and initiation of several signal transduction pathways that control cell proliferation, apoptosis, differentiation and migration in several tissues. The activity of SCF/c-KIT system is linked with the phosphatidylinositol 3-kinase (PI3-K), the Src, the Janus kinase/signal transducers and activators of transcription (JAK/STAT), the phospholipase-C (PLC-γ) and the mitogen-activated protein kinase (MAPK) pathways. Moreover, it has been reported that cancer cases display an overactivation of c-KIT due to the presence of gain-of-function mutations or receptor overexpression, which renders c-KIT a tempting target for cancer treatment. In the case of male cancers the most documented activated pathways are the PI3-K and Src, both enhancing abnormal cell proliferation. It is also known that the Src activity in prostate cancer cases depends on the presence of tr-KIT, the cytoplasmic truncated variant of c-KIT that is specifically expressed in tumour tissues and, thus, a very interesting target for drug development. The present review provides an overview of the signalling pathways activated by SCF/c-KIT and discusses the potential application of c-KIT inhibitors for treatment of testicular and prostatic cancers.

  4. Tofacitinib, an oral Janus kinase inhibitor: analysis of malignancies across the rheumatoid arthritis clinical development programme

    PubMed Central

    Curtis, Jeffrey R; Lee, Eun Bong; Kaplan, Irina V; Kwok, Kenneth; Geier, Jamie; Benda, Birgitta; Soma, Koshika; Wang, Lisy; Riese, Richard

    2016-01-01

    Objectives Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis (RA). To further assess the potential role of Janus kinase inhibition in the development of malignancies, we performed an integrated analysis of data from the tofacitinib RA clinical development programme. Methods Malignancy data (up to 10 April 2013) were pooled from six phase II, six Phase III and two long-term extension (LTE) studies involving tofacitinib. In the phase II and III studies, patients with moderate-to-severe RA were randomised to various tofacitinib doses as monotherapy or with background non-biological disease-modifying antirheumatic drugs (DMARDs), mainly methotrexate. The LTE studies (tofacitinib 5 or 10 mg twice daily) enrolled patients from qualifying prior phase I, II and III index studies. Results Of 5671 tofacitinib-treated patients, 107 developed malignancies (excluding non-melanoma skin cancer (NMSC)). The most common malignancy was lung cancer (n=24) followed by breast cancer (n=19), lymphoma (n=10) and gastric cancer (n=6). The rate of malignancies by 6-month intervals of tofacitinib exposure indicates rates remained stable over time. Standardised incidence ratios (comparison with Surveillance, Epidemiology and End Results) for all malignancies (excluding NMSC) and selected malignancies (lung, breast, lymphoma, NMSC) were within the expected range of patients with moderate-to-severe RA. Conclusions The overall rates and types of malignancies observed in the tofacitinib clinical programme remained stable over time with increasing tofacitinib exposure. PMID:25902789

  5. Overexpression of microRNA-375 impedes platelet-derived growth factor-induced proliferation and migration of human fetal airway smooth muscle cells by targeting Janus kinase 2.

    PubMed

    Ji, Yamei; Yang, Xin; Su, Huixia

    2018-02-01

    The abnormal proliferation and migration of airway smooth muscle (ASM) cells play a critical role in airway remodeling during the development of asthma. MicroRNAs (miRNAs) have emerged as critical regulators of ASM cell proliferation and migration in airway remodeling. In this study, we aimed to investigate the potential role of miR-375 in the regulation of platelet-derived growth factor (PDGF)-induced fetal ASM cell proliferation and migration. Our results showed that miR-375 expression was significantly decreased in fetal ASM cells that were treated with PDGF. Functional data showed that overexpression of miR-375 inhibited the proliferation and migration of fetal ASM cells, whereas inhibition of miR-375 enhanced the proliferation and migration of fetal ASM cells. The results of bioinformatics analysis and a dual-luciferase reporter assay showed that miR-375 binds directly to the 3'-untranslated region of Janus kinase 2 (JAK2). Further data confirmed that miR-375 negatively regulates the expression of JAK2 in fetal ASM cells. Moreover, miR-375 also impeded the PDGF-induced activation of signal transducer and activator of transcription 3 (STAT3) in fetal ASM cells. However, restoration of JAK2 expression partially reversed the inhibitory effect of miR-375 on fetal ASM cell proliferation and migration. Overall, our results demonstrate that miR-375 inhibits fetal ASM cell proliferation and migration by targeting JAK2/STAT3 signaling. Our study provides a potential therapeutic target for the development of novel treatment strategies for pediatric asthma. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  6. Membrane Transfer from Mononuclear Cells to Polymorphonuclear Neutrophils Transduces Cell Survival and Activation Signals in the Recipient Cells via Anti-Extrinsic Apoptotic and MAP Kinase Signaling Pathways.

    PubMed

    Li, Ko-Jen; Wu, Cheng-Han; Shen, Chieh-Yu; Kuo, Yu-Min; Yu, Chia-Li; Hsieh, Song-Chou

    2016-01-01

    The biological significance of membrane transfer (trogocytosis) between polymorphonuclear neutrophils (PMNs) and mononuclear cells (MNCs) remains unclear. We investigated the biological/immunological effects and molecular basis of trogocytosis among various immune cells in healthy individuals and patients with active systemic lupus erythematosus (SLE). By flow cytometry, we determined that molecules in the immunological synapse, including HLA class-I and-II, CD11b and LFA-1, along with CXCR1, are exchanged among autologous PMNs, CD4+ T cells, and U937 cells (monocytes) after cell-cell contact. Small interfering RNA knockdown of the integrin adhesion molecule CD11a in U937 unexpectedly enhanced the level of total membrane transfer from U937 to PMN cells. Functionally, phagocytosis and IL-8 production by PMNs were enhanced after co-culture with T cells. Total membrane transfer from CD4+ T to PMNs delayed PMN apoptosis by suppressing the extrinsic apoptotic molecules, BAX, MYC and caspase 8. This enhancement of activities of PMNs by T cells was found to be mediated via p38- and P44/42-Akt-MAP kinase pathways and inhibited by the actin-polymerization inhibitor, latrunculin B, the clathrin inhibitor, Pitstop-2, and human immunoglobulin G, but not by the caveolin inhibitor, methyl-β-cyclodextrin. In addition, membrane transfer from PMNs enhanced IL-2 production by recipient anti-CD3/anti-CD28 activated MNCs, and this was suppressed by inhibitors of mitogen-activated protein kinase (PD98059) and protein kinase C (Rottlerin). Of clinical significance, decreased total membrane transfer from PMNs to MNCs in patients with active SLE suppressed mononuclear IL-2 production. In conclusion, membrane transfer from MNCs to PMNs, mainly at the immunological synapse, transduces survival and activation signals to enhance PMN functions and is dependent on actin polymerization, clathrin activation, and Fcγ receptors, while membrane transfer from PMNs to MNCs depends on MAP kinase and

  7. Tofacitinib, an Oral Janus Kinase Inhibitor: Perspectives in Dermatology.

    PubMed

    Kostovic, Kresimir; Gulin, Sandra J; Mokos, Zrinka B; Ceovic, Romana

    2017-05-31

    Tofacitinib (formerly known as CP-690,550, CP690550, tasocitinib), a novel selective immunosuppressant, is a small molecule classified as Janus kinase inhibitor. The aim of this review article is to present updated data summary on the tofacitinib in the field of dermatology. We undertook a structured search of bibliographic databases for peer-reviewed scientific articles, including review articles, original research articles as well as case report articles based on inclusion/exclusion criteria. Technical reports on tofacitinib from U.S. Food and Drug Administration and European Medical Agency were also included. Forty-three papers were included in this review. We report current data on tofacitinib chemical properties, pharmacology, non-clinical toxicity, as well as efficacy and safety in potential new indications in dermatology: psoriasis, alopecia areata, vitiligo, atopic dermatitis and nail dystrophy associated with alopecia areata. JAK/STAT pathway has an important role in the pathogenesis of psoriasis, alopecia areata, atopic dermatitis, and vitiligo. Despite encouraging efficacy, due to concerns about the overall safety profile of tofacitinib, additional studies will have to determine the adequate risk-to-benefit ratio. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  8. Signal transducers and activators of transcription (STATs) gene polymorphisms related with susceptibility to rheumatic heart disease in north Indian population.

    PubMed

    Gupta, Usha; Mir, Snober S; Srivastava, Apurva; Garg, Naveen; Agarwal, Surendra K; Pande, Shantanu; Mittal, Balraj

    2014-09-01

    Rheumatic heart disease (RHD) is the most serious complication of heart that comprises inflammatory reactions in heart valves. Cytokines play a critical role in triggering inflammatory reactions and they activate the Janus Kinase/Signal Transducers and Activators of Transcription (JAK/STAT) signaling pathway. Altered signals of STATs play important roles in the balance between proinflammatory and anti-inflammatory cytokines in inflammatory diseases. The aim of the present study was to investigate for the association of polymorphisms related with STAT genes, i.e. STAT3 (rs4796793 C/G) and STAT5b (rs6503691 C/T) with the pathogenesis of RHD. This case-control association study involved 300 healthy controls and 400 RHD patients from North Indian Population. We categorized RHD patients into two subgroups based on involvement of heart valves, mitral valve lesion alone (MVL), and combined valve lesions including mitral valve (CVL). Genotyping was done by RFLP/Taqman probes. We observed that STAT3 CG and GG genotypes were significantly associated with RHD (p=0.030 and p=0.014 respectively), STAT5b CT and TT genotypes were also significantly associated with RHD (p≤0.001). Haplotype analysis revealed that minor alleles of both the variants (Grs4796793Trs6503691) were significantly associated (p<0.0001) with increased risk of the disease susceptibility irrespective of gender or age of onset of the disease. However, the polymorphisms were not involved in severity of RHD as both MVL and CVL patients were equally affected. STAT Grs4796793Trs6503691 carriers may have reduced production of STAT3 leading to damage of heart valves. Thus, STAT genes polymorphisms may be useful markers for the identification of individuals with high risk of RHD in the susceptible population. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Evaluation of Signaling Pathways Involved in γ-Globin Gene Induction Using Fetal Hemoglobin Inducer Drugs.

    PubMed

    Rahim, Fakher; Allahmoradi, Hossein; Salari, Fatemeh; Shahjahani, Mohammad; Fard, Ali Dehghani; Hosseini, Seyed Ahmad; Mousakhani, Hadi

    2013-01-01

    Potent induction of fetal hemoglobin (HbF) production results in alleviating the complications of β-thalassemia and sickle cell disease (SCD). HbF inducer agents can trigger several molecular signaling pathways critical for erythropoiesis. Janus kinase/Signal transducer and activator of transcription (JAK/STAT), mitogen activated protein kinas (MAPK) and Phosphoinositide 3-kinase (PI3K) are considered as main signaling pathways, which may play a significant role in HbF induction. All these signaling pathways are triggered by erythropoietin (EPO) as the main growth factor inducing erythroid differentiation, when it binds to its cell surface receptor, erythropoietin receptor (EPO-R) HbF inducer agents have been shown to upregulate HbF production level by triggering certain signaling pathways. As a result, understanding the pivotal signaling pathways influencing HbF induction leads to effective upregulation of HbF. In this mini review article, we try to consider the correlation between HbF inducer agents and their molecular mechanisms of γ-globin upregulation. Several studies suggest that activating P38 MAPK, RAS and STAT5 signaling pathways result in efficient HbF induction. Nevertheless, the role of other erythroid signaling pathways in HbF induction seems to be indispensible and should be emphasized.

  10. Role of IL-9 and STATs in hematological malignancies (Review).

    PubMed

    Chen, Na; Wang, Xin

    2014-03-01

    Although interleukin-9 (IL-9) exhibits pleiotropic functions in the immune system, it remains a well-known cytokine in hematological malignancies. Previous cell culture and animal model studies have revealed that the Janus kinase-signal transducer and activator of transcription signaling pathway, which may be activated by a number of cytokines including IL-9, is critical in hematological malignancies. The current review summarizes the characterization of the biological activities of IL-9, highlights the clearly defined roles of the cytokine, and outlines questions with regard to the functions of IL-9 that require further exploration and their downstream signaling proteins, signal transducers and activators of transcription.

  11. Signal conditioner for potentiometer type transducers

    NASA Technical Reports Server (NTRS)

    Armentrout, E. C.; Gross, E.

    1973-01-01

    Low cost method is described for signal conditioning of pot-type transducers utilizing printed circuitry. Conditioner fits into standard rack, accommodates 56 channels, and can be operated by one attendant.

  12. Association of a genetic marker at the bovine Janus kinase 2 locus (JAK2/RsaI) with milk production traits of four cattle breeds.

    PubMed

    Szewczuk, Małgorzata

    2015-08-01

    In addition to the main components of the somatotrophic axis (GH/GHR/IGF-I/IGF-IR), great importance in the control of growth and development is also attached to the Janus kinase 2 (JAK2) pathway. Induced by the GH/GHR complex, JAK2 activates signal transducer and activator of transcription 5 (STAT5), and in consequence, may be involved in the regulation of expression of insulin-like growth factor I (IGF-I) in the mammary gland. Silent mutation (rs110298451) has been identified within exon 20 using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). A total of 904 individuals of four dairy or dual-purpose breeds (Polish Holstein-Friesian, Montbeliarde, Simmental and Jersey) were genotyped. A genotypic imbalance in the populations was observed. In the case of dual-purpose breeds (Montbeliarde and Simmental), the frequencies of both alleles were almost equal. In contrary, the JAK2G allele was predominant in the Polish Holstein-Friesian breed while JAK2A allele in Jersey. A pronounced relationship between JAK2/RsaI polymorphism and milk production traits was found where, irrespective of breed and lactation order, the GG genotype was significantly associated with higher milk, protein and fat yields, as compared to the AA genotype. Heterozygous individuals were generally characterised by intermediate values of the analysed milk traits. It can be argued that the JAK2 gene polymorphism is a potential marker for milk production traits. However, due to the fact that rs110298451 SNP does not directly affect amino acid sequence, other association studies involving missense mutation should also be performed.

  13. Tofacitinib, an oral Janus kinase inhibitor: analysis of malignancies across the rheumatoid arthritis clinical development programme.

    PubMed

    Curtis, Jeffrey R; Lee, Eun Bong; Kaplan, Irina V; Kwok, Kenneth; Geier, Jamie; Benda, Birgitta; Soma, Koshika; Wang, Lisy; Riese, Richard

    2016-05-01

    Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis (RA). To further assess the potential role of Janus kinase inhibition in the development of malignancies, we performed an integrated analysis of data from the tofacitinib RA clinical development programme. Malignancy data (up to 10 April 2013) were pooled from six phase II, six Phase III and two long-term extension (LTE) studies involving tofacitinib. In the phase II and III studies, patients with moderate-to-severe RA were randomised to various tofacitinib doses as monotherapy or with background non-biological disease-modifying antirheumatic drugs (DMARDs), mainly methotrexate. The LTE studies (tofacitinib 5 or 10 mg twice daily) enrolled patients from qualifying prior phase I, II and III index studies. Of 5671 tofacitinib-treated patients, 107 developed malignancies (excluding non-melanoma skin cancer (NMSC)). The most common malignancy was lung cancer (n=24) followed by breast cancer (n=19), lymphoma (n=10) and gastric cancer (n=6). The rate of malignancies by 6-month intervals of tofacitinib exposure indicates rates remained stable over time. Standardised incidence ratios (comparison with Surveillance, Epidemiology and End Results) for all malignancies (excluding NMSC) and selected malignancies (lung, breast, lymphoma, NMSC) were within the expected range of patients with moderate-to-severe RA. The overall rates and types of malignancies observed in the tofacitinib clinical programme remained stable over time with increasing tofacitinib exposure. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  14. Kinome and Transcriptome Profiling Reveal Broad and Distinct Activities of Erlotinib, Sunitinib, and Sorafenib in the Mouse Heart and Suggest Cardiotoxicity From Combined Signal Transducer and Activator of Transcription and Epidermal Growth Factor Receptor Inhibition.

    PubMed

    Stuhlmiller, Timothy J; Zawistowski, Jon S; Chen, Xin; Sciaky, Noah; Angus, Steven P; Hicks, Sean T; Parry, Traci L; Huang, Wei; Beak, Ju Youn; Willis, Monte S; Johnson, Gary L; Jensen, Brian C

    2017-10-19

    Most novel cancer therapeutics target kinases that are essential to tumor survival. Some of these kinase inhibitors are associated with cardiotoxicity, whereas others appear to be cardiosafe. The basis for this distinction is unclear, as are the molecular effects of kinase inhibitors in the heart. We administered clinically relevant doses of sorafenib, sunitinib (cardiotoxic multitargeted kinase inhibitors), or erlotinib (a cardiosafe epidermal growth factor receptor inhibitor) to mice daily for 2 weeks. We then compared the effects of these 3 kinase inhibitors on the cardiac transcriptome using RNAseq and the cardiac kinome using multiplexed inhibitor beads coupled with mass spectrometry. We found unexpectedly broad molecular effects of all 3 kinase inhibitors, suggesting that target kinase selectivity does not define either the molecular response or the potential for cardiotoxicity. Using in vivo drug administration and primary cardiomyocyte culture, we also show that the cardiosafety of erlotinib treatment may result from upregulation of the cardioprotective signal transducer and activator of transcription 3 pathway, as co-treatment with erlotinib and a signal transducer and activator of transcription inhibitor decreases cardiac contractile function and cardiomyocyte fatty acid oxidation. Collectively our findings indicate that preclinical kinome and transcriptome profiling may predict the cardiotoxicity of novel kinase inhibitors, and suggest caution for the proposed therapeutic strategy of combined signal transducer and activator of transcription/epidermal growth factor receptor inhibition for cancer treatment. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  15. Pulse transducer with artifact signal attenuator. [heart rate sensors

    NASA Technical Reports Server (NTRS)

    Cash, W. H., Jr.; Polhemus, J. T. (Inventor)

    1980-01-01

    An artifact signal attenuator for a pulse rate sensor is described. The circuit for attenuating background noise signals is connected with a pulse rate transducer which has a light source and a detector for light reflected from blood vessels of a living body. The heart signal provided consists of a modulated dc signal voltage indicative of pulse rate. The artifact signal resulting from light reflected from the skin of the body comprises both a constant dc signal voltage and a modulated dc signal voltage. The amplitude of the artifact signal is greater and the frequency less than that of the heart signal. The signal attenuator circuit includes an operational amplifier for canceling the artifact signal from the output signal of the transducer and has the capability of meeting packaging requirements for wrist-watch-size packages.

  16. TRP channels: sensors and transducers of gasotransmitter signals

    PubMed Central

    Takahashi, Nobuaki; Kozai, Daisuke; Mori, Yasuo

    2012-01-01

    The transient receptor potential (trp) gene superfamily encodes cation channels that act as multimodal sensors for a wide variety of stimuli from outside and inside the cell. Upon sensing, they transduce electrical and Ca2+ signals via their cation channel activities. These functional features of TRP channels allow the body to react and adapt to different forms of environmental changes. Indeed, members of one class of TRP channels have emerged as sensors of gaseous messenger molecules that control various cellular processes. Nitric oxide (NO), a vasoactive gaseous molecule, regulates TRP channels directly via cysteine (Cys) S-nitrosylation or indirectly via cyclic GMP (cGMP)/protein kinase G (PKG)-dependent phosphorylation. Recent studies have revealed that changes in the availability of molecular oxygen (O2) also control the activation of TRP channels. Anoxia induced by O2-glucose deprivation and severe hypoxia (1% O2) activates TRPM7 and TRPC6, respectively, whereas TRPA1 has recently been identified as a novel sensor of hyperoxia and mild hypoxia (15% O2) in vagal and sensory neurons. TRPA1 also detects other gaseous molecules such as hydrogen sulfide (H2S) and carbon dioxide (CO2). In this review, we focus on how signaling by gaseous molecules is sensed and integrated by TRP channels. PMID:22934072

  17. Interleukin-6 signalling: more than Jaks and STATs.

    PubMed

    Eulenfeld, René; Dittrich, Anna; Khouri, Christina; Müller, Pia J; Mütze, Barbara; Wolf, Alexandra; Schaper, Fred

    2012-01-01

    The hallmark of signalling by many cytokines is the activation of the Janus kinase (Jak)/signal transducer and activator of transcription (STAT) pathway. However, cytokines additionally activate other pathways. In past years we realised that these pathways significantly contribute to the physiological functions of IL-6 and pathophysiological functions in the context of many inflammatory and proliferative diseases. Whereas other articles in this issue of the European Journal of Cell Biology focus on STAT activation and its regulation we here aim to summarise our knowledge and some remaining questions on interleukin-6 (IL-6)-induced STAT-independent pathways as well as the cross-talk with the Jak/STAT pathway. In the early stages of studying cytokine signalling we were used to analysing individual signalling pathways. These days we know about the importance of both, the crosstalk between pathways initiated by combinations of cytokines as well as the crosstalk between individual pathways initiated by a single cytokine. Whereas the inter-cytokine crosstalk can be studied relatively easily, more sophisticated experimental approaches are required to elucidate the intra-cytokine crosstalk. Copyright © 2011 Elsevier GmbH. All rights reserved.

  18. The kinase activity of fibroblast growth factor receptor 3 with activation loop mutations affects receptor trafficking and signaling.

    PubMed

    Lievens, Patricia M-J; Mutinelli, Chiara; Baynes, Darcie; Liboi, Elio

    2004-10-08

    Amino acid substitutions at the Lys-650 codon within the activation loop kinase domain of fibroblast growth factor receptor 3 (FGFR3) result in graded constitutive phosphorylation of the receptor. Accordingly, the Lys-650 mutants are associated with dwarfisms with graded clinical severity. To assess the importance of the phosphorylation level on FGFR3 maturation along the secretory pathway, hemagglutinin A-tagged derivatives were studied. The highly activated SADDAN (severe achondroplasia with developmental delay and acanthosis nigricans) mutant accumulates in its immature and phosphorylated form in the endoplasmic reticulum (ER), which fails to be degraded. Furthermore, the Janus kinase (Jak)/STAT pathway is activated from the ER by direct recruitment of Jak1. Abolishing the autocatalytic property of the mutated FGFR3 by replacing the critical Tyr-718 reestablishes the receptor full maturation and inhibits signaling. Differently, the low activated hypochondroplasia mutant is present as a mature phosphorylated form on the plasma membrane, although with a delayed transition in the ER, and is completely processed. Signaling does not occur in the presence of brefeldin A; instead, STAT1 is activated when protein secretion is blocked with monensin, suggesting that the hypochondroplasia receptor signals at the exit from the ER. Our results suggest that kinase activity affects FGFR3 trafficking and determines the spatial segregation of signaling pathways. Consequently, the defect in down-regulation of the highly activated receptors results in the increased signaling capacity from the intracellular compartments, and this may determine the severity of the diseases.

  19. Protein kinase inhibitors in the treatment of inflammatory and autoimmune diseases

    PubMed Central

    Patterson, H; Nibbs, R; McInnes, I; Siebert, S

    2014-01-01

    Protein kinases mediate protein phosphorylation, which is a fundamental component of cell signalling, with crucial roles in most signal transduction cascades: from controlling cell growth and proliferation to the initiation and regulation of immunological responses. Aberrant kinase activity is implicated in an increasing number of diseases, with more than 400 human diseases now linked either directly or indirectly to protein kinases. Protein kinases are therefore regarded as highly important drug targets, and are the subject of intensive research activity. The success of small molecule kinase inhibitors in the treatment of cancer, coupled with a greater understanding of inflammatory signalling cascades, has led to kinase inhibitors taking centre stage in the pursuit for new anti-inflammatory agents for the treatment of immune-mediated diseases. Herein we discuss the main classes of kinase inhibitors; namely Janus kinase (JAK), mitogen-activated protein kinase (MAPK) and spleen tyrosine kinase (Syk) inhibitors. We provide a mechanistic insight into how these inhibitors interfere with kinase signalling pathways and discuss the clinical successes and failures in the implementation of kinase-directed therapeutics in the context of inflammatory and autoimmune disorders. PMID:24313320

  20. Deregulated expression of Cdc6 as BCR/ABL-dependent survival factor in chronic myeloid leukemia cells.

    PubMed

    Zhang, Jia-Hua; He, Yan-Li; Zhu, Rui; Du, Wen; Xiao, Jun-Hua

    2017-06-01

    Chronic myeloid leukemia is characterized by the presence of the reciprocal translocation t(9;22) and the BCR/ABL oncogene. The BCR/ABL oncogene activates multiple signaling pathways and involves the dysregulation of oncogenes during the progression of chronic myeloid leukemia. The cell division cycle protein 6, an essential regulator of DNA replication, is elevated in some human cancer cells. However, the expression of cell division cycle protein 6 in chronic myeloid leukemia and the underlying regulatory mechanism remain to be elucidated. In this study, our data showed that cell division cycle protein 6 expression was significantly upregulated in primary chronic myeloid leukemia cells and the chronic myeloid leukemia cell line K562 cells, as compared to the normal bone marrow mononuclear cells. BCR/ABL kinase inhibitor STI571 or BCR/ABL small interfering RNA could significantly downregulate cell division cycle protein 6 messenger RNA expression in K562 cells. Moreover, phosphoinositide 3-kinase/AKT pathway inhibitor LY294002 and Janus kinase/signal transducer and activator of transcription pathway inhibitor AG490 could downregulate cell division cycle protein 6 expression in K562 cells, but not RAS/mitogen-activated protein kinase pathway inhibitor PD98059 had such effect. Cell division cycle protein 6 gene silencing by small interfering RNA effectively resulted in decrease of proliferation, increase of apoptosis, and arrest of cell cycle in K562 cells. These findings have demonstrated that cell division cycle protein 6 overexpression may contribute to the high proliferation and low apoptosis in chronic myeloid leukemia cells and can be regulated by BCR/ABL signal transduction through downstream phosphoinositide 3-kinase/Akt and Janus kinase/signal transducer and activator of transcription pathways, suggesting cell division cycle protein 6 as a potential therapeutic target in chronic myeloid leukemia.

  1. The role of the JAK/STAT signal pathway in rheumatoid arthritis

    PubMed Central

    Malemud, Charles J.

    2018-01-01

    Proinflammatory cytokine activation of the Janus kinase/signal transducers and activators of transcription (JAK/STAT) signal transduction pathway is a critical event in the pathogenesis and progression of rheumatoid arthritis. Under normal conditions, JAK/STAT signaling reflects the influence of negative regulators of JAK/STAT, exemplified by the suppressor of cytokine signaling and protein inhibitor of activated STAT. However, in rheumatoid arthritis (RA) both of these regulators are dysfunctional. Thus, continuous activation of JAK/STAT signaling in RA synovial joints results in the elevated level of matrix metalloproteinase gene expression, increased frequency of apoptotic chondrocytes and most prominently ‘apoptosis resistance’ in the inflamed synovial tissue. Tofacitinib, a JAK small molecule inhibitor, with selectivity for JAK2/JAK3 was approved by the United States Food and Drug Administration (US FDA) for the therapy of RA. Importantly, tofacitinib has demonstrated significant clinical efficacy for RA in the post-US FDA-approval surveillance period. Of note, the success of tofacitinib has spurred the development of JAK1, JAK2 and other JAK3-selective small molecule inhibitors, some of which have also entered the clinical setting, whereas other JAK inhibitors are currently being evaluated in RA clinical trials. PMID:29942363

  2. Absence of suppressor of cytokine signalling 3 reduces self-renewal and promotes differentiation in murine embryonic stem cells.

    PubMed

    Forrai, Ariel; Boyle, Kristy; Hart, Adam H; Hartley, Lynne; Rakar, Steven; Willson, Tracy A; Simpson, Ken M; Roberts, Andrew W; Alexander, Warren S; Voss, Anne K; Robb, Lorraine

    2006-03-01

    Leukemia inhibitory factor (LIF) is required to maintain pluripotency and permit self-renewal of murine embryonic stem (ES) cells. LIF binds to a receptor complex of LIFR-beta and gp130 and signals via the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway, with signalling attenuated by suppressor of cytokine signalling (SOCS) proteins. Recent in vivo studies have highlighted the role of SOCS-3 in the negative regulation of signalling via gp130. To determine the role of SOCS-3 in ES cell biology, SOCS-3-null ES cell lines were generated. When cultured in LIF levels that sustain self-renewal of wild-type cells, SOCS-3-null ES cell lines exhibited less self-renewal and greater differentiation into primitive endoderm. The absence of SOCS-3 enhanced JAK-STAT and extracellular signal-related kinase 1/2 (ERK-1/2)-mitogen-activated protein kinase (MAPK) signal transduction via gp130, with higher levels of phosphorylated STAT-1, STAT-3, SH-2 domain-containing cytoplasmic protein tyrosine phosphatase 2 (SHP-2), and ERK-1/2 in steady state and in response to LIF stimulation. Attenuation of ERK signalling by the addition of MAPK/ERK kinase (MEK) inhibitors to SOCS-3-null ES cell cultures rescued the differentiation phenotype, but did not restore proliferation to wild-type levels. In summary, SOCS-3 plays a crucial role in the regulation of the LIF signalling pathway in murine ES cells. Its absence perturbs the balance between activation of the JAK-STAT and SHP-2-ERK-1/2-MAPK pathways, resulting in less self-renewal and a greater potential for differentiation into the primitive endoderm lineage.

  3. Tyrosine Kinase 2-mediated Signal Transduction in T Lymphocytes Is Blocked by Pharmacological Stabilization of Its Pseudokinase Domain*

    PubMed Central

    Tokarski, John S.; Zupa-Fernandez, Adriana; Tredup, Jeffrey A.; Pike, Kristen; Chang, ChiehYing; Xie, Dianlin; Cheng, Lihong; Pedicord, Donna; Muckelbauer, Jodi; Johnson, Stephen R.; Wu, Sophie; Edavettal, Suzanne C.; Hong, Yang; Witmer, Mark R.; Elkin, Lisa L.; Blat, Yuval; Pitts, William J.; Weinstein, David S.; Burke, James R.

    2015-01-01

    Inhibition of signal transduction downstream of the IL-23 receptor represents an intriguing approach to the treatment of autoimmunity. Using a chemogenomics approach marrying kinome-wide inhibitory profiles of a compound library with the cellular activity against an IL-23-stimulated transcriptional response in T lymphocytes, a class of inhibitors was identified that bind to and stabilize the pseudokinase domain of the Janus kinase tyrosine kinase 2 (Tyk2), resulting in blockade of receptor-mediated activation of the adjacent catalytic domain. These Tyk2 pseudokinase domain stabilizers were also shown to inhibit Tyk2-dependent signaling through the Type I interferon receptor but not Tyk2-independent signaling and transcriptional cellular assays, including stimulation through the receptors for IL-2 (JAK1- and JAK3-dependent) and thrombopoietin (JAK2-dependent), demonstrating the high functional selectivity of this approach. A crystal structure of the pseudokinase domain liganded with a representative example showed the compound bound to a site analogous to the ATP-binding site in catalytic kinases with features consistent with high ligand selectivity. The results support a model where the pseudokinase domain regulates activation of the catalytic domain by forming receptor-regulated inhibitory interactions. Tyk2 pseudokinase stabilizers, therefore, represent a novel approach to the design of potent and selective agents for the treatment of autoimmunity. PMID:25762719

  4. Contemplative Janus

    NASA Image and Video Library

    2015-01-19

    Janus (111 miles or 179 kilometers across) seems to almost stare off into the distance, contemplating deep, moonish thoughts as the F ring stands by at the bottom of this image. From this image, it is easy to distinguish Janus' shape from that of a sphere. Many of Saturn's smaller moons have similarly irregular shapes that scientists believe may give clues to their origins and internal structure. Models combining the dynamics of this moon with its shape imply the existence of mass inhomogeneities within Janus. This would be a surprising result for a body the size of Janus. By studying more images of Janus, scientists may be able confirm this finding and determine just how complicated the internal structure of this small body is. This image is roughly centered on the side of Janus which faces away from Saturn. North on Janus is up and rotated 3 degrees to the right. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on March 28, 2012. The view was obtained at a distance of approximately 54,000 miles (87,000 kilometers) from Janus. Image scale is 1,700 feet (520 meters) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA18299

  5. Simulation of transducer-couplant effects on broadband ultrasonic signals

    NASA Technical Reports Server (NTRS)

    Vary, A.

    1980-01-01

    The increasing use of broadband, pulse-echo ultrasonics in nondestructive evaluation of flaws and material properties has generated a need for improved understanding of the way signals are modified by coupled and bonded thin-layer interfaces associated with transducers. This understanding is most important when using frequency spectrum analyses for characterizing material properties. In this type of application, signals emanating from material specimens can be strongly influenced by couplant and bond-layers in the acoustic path. Computer synthesized waveforms were used to simulate a range of interface conditions encountered in ultrasonic transducer systems operating in the 20 to 80 MHz regime. The adverse effects of thin-layer multiple reflections associated with various acoustic impedance conditions are demonstrated. The information presented is relevant to ultrasonic transducer design, specimen preparation, and couplant selection.

  6. Insulin-Like Growth Factor 1 Receptor and p38 Mitogen-Activated Protein Kinase Signals Inversely Regulate Signal Transducer and Activator of Transcription 3 Activity to Control Human Dental Pulp Stem Cell Quiescence, Propagation, and Differentiation

    PubMed Central

    Vandomme, Jerome; Touil, Yasmine; Ostyn, Pauline; Olejnik, Cecile; Flamenco, Pilar; El Machhour, Raja; Segard, Pascaline; Masselot, Bernadette; Bailliez, Yves; Formstecher, Pierre

    2014-01-01

    Dental pulp stem cells (DPSCs) remain quiescent until activated in response to severe dental pulp damage. Once activated, they exit quiescence and enter regenerative odontogenesis, producing reparative dentin. The factors and signaling molecules that control the quiescence/activation and commitment to differentiation of human DPSCs are not known. In this study, we determined that the inhibition of insulin-like growth factor 1 receptor (IGF-1R) and p38 mitogen-activated protein kinase (p38 MAPK) signaling commonly activates DPSCs and promotes their exit from the G0 phase of the cell cycle as well as from the pyronin Ylow stem cell compartment. The inhibition of these two pathways, however, inversely determines DPSC fate. In contrast to p38 MAPK inhibitors, IGF-1R inhibitors enhance dental pulp cell sphere-forming capacity and reduce the cells' colony-forming capacity without inducing cell death. The inverse cellular changes initiated by IGF-1R and p38 MAPK inhibitors were accompanied by inverse changes in the levels of active signal transducer and activator of transcription 3 (STAT3) factor, inactive glycogen synthase kinase 3, and matrix extracellular phosphoglycoprotein, a marker of early odontoblast differentiation. Our data suggest that there is cross talk between the IGF-1R and p38 MAPK signaling pathways in DPSCs and that the signals provided by these pathways converge at STAT3 and inversely regulate its activity to maintain quiescence or to promote self-renewal and differentiation of the cells. We propose a working model that explains the possible interactions between IGF-1R and p38 MAPK at the molecular level and describes the cellular consequences of these interactions. This model may inspire further fundamental study and stimulate research on the clinical applications of DPSC in cellular therapy and tissue regeneration. PMID:24266654

  7. Sophoraflavanone G induces apoptosis of human cancer cells by targeting upstream signals of STATs.

    PubMed

    Kim, Byung-Hak; Won, Cheolhee; Lee, Yun-Han; Choi, Jung Sook; Noh, Kum Hee; Han, Songhee; Lee, Haeri; Lee, Chang Seok; Lee, Dong-Sup; Ye, Sang-Kyu; Kim, Myoung-Hwan

    2013-10-01

    Aberrantly activated signal transducer and activator of transcription (STAT) proteins are implicated with human cancers and represent essential roles for cancer cell survival and proliferation. Therefore, the development of small-molecule inhibitors of STAT signaling bearing pharmacological activity has therapeutic potential for the treatment of human cancers. In this study, we identified sophoraflavanone G as a novel small-molecule inhibitor of STAT signaling in human cancer cells. Sophoraflavanone G inhibited tyrosine phosphorylation of STAT proteins in Hodgkin's lymphoma and tyrosine phosphorylation of STAT3 in solid cancer cells by inhibiting phosphorylation of the Janus kinase (JAK) proteins, Src family tyrosine kinases, such as Lyn and Src, Akt, and ERK1/2. In addition, sophoraflavanone G inhibited STAT5 phosphorylation in murine-bone-marrow-derived pro-B cells transfected with translocated Ets Leukemia (TEL)-JAKs and cytokine-induced rat pre-T lymphoma cells, as well as STAT5b reporter activity in TEL-JAKs and STAT5b reporter systems. Sophoraflavanone G also inhibited nuclear factor-κB (NF-κB) signaling in multiple myeloma cells. Furthermore, sophoraflavanone G inhibited cancer cell proliferation and induced apoptosis by regulating the expression of apoptotic and anti-apoptotic proteins. Our data suggest that sophoraflavanone G is a novel small-molecule inhibitor of STAT signaling by targeting upstream signals of STATs that may have therapeutic potential for cancers caused by persistently activated STAT proteins. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Significant reduction of acute cardiac allograft rejection by selective janus kinase-1/3 inhibition using R507 and R545.

    PubMed

    Deuse, Tobias; Hua, Xiaoqin; Taylor, Vanessa; Stubbendorff, Mandy; Baluom, Muhammad; Chen, Yan; Park, Gary; Velden, Joachim; Streichert, Thomas; Reichenspurner, Hermann; Robbins, Robert C; Schrepfer, Sonja

    2012-10-15

    Selective inhibition of lymphocyte activation through abrogation of signal 3-cytokine transduction emerges as a new strategy for immunosuppression. This is the first report on the novel Janus kinase (JAK)1/3 inhibitors R507 and R545 for prevention of acute allograft rejection. Pharmacokinetic and in vitro enzyme inhibition assays were performed to characterize the drugs. Heterotopic Brown Norway-Lewis heart transplantations were performed to study acute cardiac allograft rejection, graft survival, suppression of cellular host responsiveness, and antibody production. Therapeutic and subtherapeutic doses of R507 (60 and 15 mg/kg 2 times per day) and R545 (20 and 5 mg/kg 2 times per day) were compared with those of tacrolimus (Tac; 4 and 1 mg/kg once per day). Plasma levels of R507 and R545 were sustained high for several hours. Cell-based enzyme assays showed selective inhibition of JAK1/3-dependent pathways with 20-fold or greater selectivity over JAK2 and Tyrosine kinase 2 kinases. After heart transplantation, both JAK1/3 inhibitors reduced early mononuclear graft infiltration, even significantly more potent than Tac. Intragraft interferon-γ release was significantly reduced by R507 and R545, and for interleukin-10 suppression, they were even significantly more potent than Tac. Both JAK1/3 inhibitors and Tac were similarly effective in reducing the host Th1 and Th2, but not Th17, responsiveness and similarly prevented donor-specific immunoglobulin M antibody production. Subtherapeutic and therapeutic R507 and R545 doses prolonged the mean graft survival and were similarly effective as 1 and 4 mg/kg Tac, respectively. In combination regimens, however, only R507 showed highly beneficial synergistic drug interactions with Tac. Both R507 and R545 are potent novel immunosuppressants with favorable pharmacokinetics and high JAK1/3 selectivity, but only R507 synergistically interacts with Tac.

  9. Systemic inhibition of Janus kinase induces browning of white adipose tissue and ameliorates obesity-related metabolic disorders.

    PubMed

    Qurania, Kikid Rucira; Ikeda, Koji; Wardhana, Donytra Arby; Barinda, Agian Jeffilano; Nugroho, Dhite Bayu; Kuribayashi, Yuko; Rahardini, Elda Putri; Rinastiti, Pranindya; Ryanto, Gusty Rizky Teguh; Yagi, Keiko; Hirata, Ken-Ichi; Emoto, Noriaki

    2018-07-07

    Browning of white adipose tissue is a promising strategy to tackle obesity. Recently, Janus kinase (JAK) inhibition was shown to induce white-to-brown metabolic conversion of adipocytes in vitro; however effects of JAK inhibition on browning and systemic metabolic health in vivo remain to be elucidated. Here, we report that systemic administration of JAK inhibitor (JAKi) ameliorated obesity-related metabolic disorders. Administration of JAKi in mice fed a high-fat diet increased UCP-1 and PRDM16 expression in white adipose tissue, indicating the browning of white adipocyte. Food intake was increased in JAKi-treated mice, while the body weight and adiposity was similar between the JAKi- and vehicle-treated mice. In consistent with the browning, thermogenic capacity was enhanced in mice treated with JAKi. Chronic inflammation in white adipose tissue was not ameliorated by JAKi-treatment. Nevertheless, insulin sensitivity was well preserved in JAKi-treated mice comparing with that in vehicle-treated mice. Serum levels of triglyceride and free fatty acid were significantly reduced by JAKi-treatment, which is accompanied by ameliorated hepatosteatosis. Our data demonstrate that systemic administration of JAKi has beneficial effects in preserving metabolic health, and thus inhibition of JAK signaling has therapeutic potential for the treatment of obesity and its-related metabolic disorders. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. Suppressor of cytokine signaling 1 (SOCS1) limits NFkappaB signaling by decreasing p65 stability within the cell nucleus.

    PubMed

    Strebovsky, Julia; Walker, Patrick; Lang, Roland; Dalpke, Alexander H

    2011-03-01

    Suppressor of cytokine signaling (SOCS) proteins are inhibitors of cytoplasmic Janus kinases (Jak) and signal transducer and activator of transcription (STAT) signaling pathways. Previously the authors surprisingly observed that SOCS1 translocated into the nucleus, which was because of the presence of a nuclear localization sequence. This report now hypothesizes that SOCS1 mediates specific functions within the nuclear compartment because it is instantly transported into the nucleus, as shown by photoactivation and live cell imaging in human HEK293 cells. The NFκB component p65 is identified as an interaction partner for SOCS1 but not for other members of the SOCS family. SOCS1 bound to p65 only within the nucleus. By means of its SOCS box domain, SOCS1 operated as a ubiquitin ligase, leading to polyubiquitination and proteasomal degradation of nuclear p65. Thus, SOCS1 limited prolonged p65 signaling and terminated expression of NFκB inducible genes. Using mutants that lack either nuclear translocation or a functional SOCS box, this report identifies genes that are regulated in a manner dependent on the nuclear availability of SOCS1. Data show that beyond its receptor-proximal function in Jak/STAT signaling, SOCS1 also regulates the duration of NFκB signaling within the cell nucleus, thus exerting a heretofore unrecognized function.

  11. Interleukin-2-induced survival of natural killer (NK) cells involving phosphatidylinositol-3 kinase-dependent reduction of ceramide through acid sphingomyelinase, sphingomyelin synthase, and glucosylceramide synthase.

    PubMed

    Taguchi, Yoshimitsu; Kondo, Tadakazu; Watanabe, Mitsumasa; Miyaji, Michihiko; Umehara, Hisanori; Kozutsumi, Yasunori; Okazaki, Toshiro

    2004-11-15

    Interleukin 2 (IL-2) rescued human natural killer (NK) KHYG-1 cells from apoptosis along with a reduction of ceramide. Conversely, an increase of ceramide inhibited IL-2-rescued survival. IL-2 deprivation-induced activation of acid sphingomyelinase (SMase) and inhibition of glucosylceramide synthase (GCS) and sphingomyelin synthase (SMS) were normalized by IL-2 supplementation. A phosphatidyl inositol-3 (PI-3) kinase inhibitor, LY294002, inhibited IL-2-rescued survival, but a mitogen-activated protein kinase inhibitor, PD98059, and an inhibitor of Janus tyrosine kinase/signal transducer and activator of transcription pathway, AG490, did not. LY294002 inhibited IL-2-induced reduction of ceramide through activation of acid SMase and inhibition of GCS and SMS, suggesting the positive involvement of PI-3 kinase in ceramide reduction through enzymatic regulation. Indeed, a constitutively active PI-3 kinase enhanced growth rate and ceramide reduction through inhibition of acid SMase and activation of GCS and SMS. Further, LY294002 inhibited IL-2-induced changes of transcriptional level as well as mRNA and protein levels in acid SMase and GCS but did not affect the stability of the mRNAs. These results suggest that PI-3 kinase-dependent reduction of ceramide through regulation of acid SMase, GCS, and SMS plays a role in IL-2-rescued survival of NK cells.

  12. Drosophila glypicans Dally and Dally-like are essential regulators for JAK/STAT signaling and Unpaired distribution in eye development

    PubMed Central

    Zhang, Yan; You, Jia; Ren, Wenyan; Lin, Xinhua

    2013-01-01

    The highly conserved janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway is a well-known signaling system that is involved in many biological processes. In Drosophila, this signaling cascade is activated by ligands of the Unpaired (Upd) family. Therefore, the regulation of Upd distribution is one of the key issues in controlling the JAK/STAT signaling activity and function. Heparan sulfate proteoglycans (HSPGs) are macromolecules that regulate the distribution of many ligand proteins including Wingless, Hedgehog and Decapentaplegic (Dpp). Here we show that during Drosophila eye development, HSPGs are also required in normal Upd distribution and JAK/STAT signaling activity. Loss of HSPG biosynthesis enzyme Brother of tout-velu (Botv), Sulfateless (Sfl), or glypicans Division abnormally delayed (Dally) and Dally-like protein (Dlp) led to reduced levels of extracellular Upd and reduction in JAK/STAT signaling activity. Overexpression of dally resulted in the accumulation of Upd and up-regulation of the signaling activity. Luciferase assay also showed that Dally promotes JAK/STAT signaling activity, and is dependent on its heparin sulfate chains. These data suggest that Dally and Dlp are essential for Upd distribution and JAK/STAT signaling activity. PMID:23313126

  13. Ethanol activates Midkine and Anaplastic lymphoma kinase signaling in neuroblastoma cells and in the brain

    PubMed Central

    He, Donghong; Chen, Hu; Muramatsu, Hisako; Lasek, Amy W.

    2015-01-01

    Alcohol engages signaling pathways in the brain. Midkine (MDK) is a neurotrophic factor that is overexpressed in the prefrontal cortex of alcoholics. MDK and one of its receptors, anaplastic lymphoma kinase (ALK), also regulate behavioral responses to ethanol in mice. The goal of this study was to determine whether MDK and ALK expression and signaling are activated by ethanol. We found that ethanol treatment of neuroblastoma cells increased MDK and ALK expression. We also assessed activation of ALK by ethanol in cells and found that ALK and ALK-dependent extracellular signal-regulated kinase (ERK) and signal transducer and activator of transcription 3 (STAT3) phosphorylation increased rapidly with ethanol exposure. Similarly, treatment of cells with recombinant MDK protein increased ALK, ERK and STAT3 phosphorylation, suggesting that ethanol may utilize MDK to activate ALK signaling. In support of this, transfection of cells with MDK siRNAs attenuated ALK signaling in response to ethanol. Ethanol also activates ERK signaling in the brain. We found that inhibition of ALK or knockout of MDK attenuated ethanol-induced ERK phosphorylation in mouse amygdala. These results demonstrate that ethanol engages MDK and ALK signaling, which has important consequences for alcohol-induced neurotoxicity and the regulation of behaviors related to alcohol abuse. PMID:26206265

  14. Hydrogen Peroxide Sensing and Signaling by Protein Kinases in the Cardiovascular System

    PubMed Central

    Burgoyne, Joseph R.; Oka, Shin-ichi; Ale-Agha, Niloofar

    2013-01-01

    Abstract Significance: Oxidants were once principally considered perpetrators of injury and disease. However, this has become an antiquated view, with cumulative evidence showing that the oxidant hydrogen peroxide serves as a signaling molecule. Hydrogen peroxide carries vital information about the redox state of the cell and is crucial for homeostatic regulation during health and adaptation to stress. Recent Advances: In this review, we examine the contemporary concepts for how hydrogen peroxide is sensed and transduced into a biological response by introducing post-translational oxidative modifications on select proteins. Oxidant sensing and signaling by kinases are of particular importance as they integrate oxidant signals into phospho-regulated pathways. We focus on CAMKII, PKA, and PKG, kinases whose redox regulation has notable impact on cardiovascular function. Critical Issues: In addition, we examine the mechanism for regulating intracellular hydrogen peroxide, considering the net concentrations that may accumulate. The effects of endogenously generated oxidants are often modeled by applying exogenous hydrogen peroxide to cells or tissues. Here we consider whether model systems exposed to exogenous hydrogen peroxide have relevance to systems where the oxidant is generated endogenously, and if so, what concentration can be justified in terms of relevance to health and disease. Future Directions: Improving our understanding of hydrogen peroxide signaling and the sensor proteins that it can modify will help us develop new strategies to regulate intracellular signaling to prevent disease. Antioxid. Redox Signal. 18, 1042–1052. PMID:22867279

  15. ZEB2 drives immature T-cell lymphoblastic leukaemia development via enhanced tumour-initiating potential and IL-7 receptor signalling

    PubMed Central

    Goossens, Steven; Radaelli, Enrico; Blanchet, Odile; Durinck, Kaat; Van der Meulen, Joni; Peirs, Sofie; Taghon, Tom; Tremblay, Cedric S.; Costa, Magdaline; Ghahremani, Morvarid Farhang; De Medts, Jelle; Bartunkova, Sonia; Haigh, Katharina; Schwab, Claire; Farla, Natalie; Pieters, Tim; Matthijssens, Filip; Van Roy, Nadine; Best, J. Adam; Deswarte, Kim; Bogaert, Pieter; Carmichael, Catherine; Rickard, Adam; Suryani, Santi; Bracken, Lauryn S.; Alserihi, Raed; Canté-Barrett, Kirsten; Haenebalcke, Lieven; Clappier, Emmanuelle; Rondou, Pieter; Slowicka, Karolina; Huylebroeck, Danny; Goldrath, Ananda W.; Janzen, Viktor; McCormack, Matthew P.; Lock, Richard B.; Curtis, David J.; Harrison, Christine; Berx, Geert; Speleman, Frank; Meijerink, Jules P. P.; Soulier, Jean; Van Vlierberghe, Pieter; Haigh, Jody J.

    2015-01-01

    Early T-cell precursor leukaemia (ETP-ALL) is a high-risk subtype of human leukaemia that is poorly understood at the molecular level. Here we report translocations targeting the zinc finger E-box-binding transcription factor ZEB2 as a recurrent genetic lesion in immature/ETP-ALL. Using a conditional gain-of-function mouse model, we demonstrate that sustained Zeb2 expression initiates T-cell leukaemia. Moreover, Zeb2-driven mouse leukaemia exhibit some features of the human immature/ETP-ALL gene expression signature, as well as an enhanced leukaemia-initiation potential and activated Janus kinase (JAK)/signal transducers and activators of transcription (STAT) signalling through transcriptional activation of IL7R. This study reveals ZEB2 as an oncogene in the biology of immature/ETP-ALL and paves the way towards pre-clinical studies of novel compounds for the treatment of this aggressive subtype of human T-ALL using our Zeb2-driven mouse model. PMID:25565005

  16. Interaction of Hepatitis C Virus Core Protein with Janus Kinase Is Required for Efficient Production of Infectious Viruses

    PubMed Central

    Lee, Choongho

    2013-01-01

    Chronic hepatitis C virus (HCV) infection is responsible for the development of liver cirrhosis and hepatocellular carcinoma. HCV core protein plays not only a structural role in the virion morphogenesis by encapsidating a virus RNA genome but also a non-structural role in HCV-induced pathogenesis by blocking innate immunity. Especially, it has been shown to regulate JAK-STAT signaling pathway through its direct interaction with Janus kinase (JAK) via its proline-rich JAK-binding motif (79PGYPWP84). However, little is known about the physiological significance of this HCV core-JAK association in the context of the virus life cycle. In order to gain an insight, a mutant HCV genome (J6/JFH1-79A82A) was constructed to express the mutant core with a defective JAK-binding motif (79AGYAWP84) using an HCV genotype 2a infectious clone (J6/JFH1). When this mutant HCV genome was introduced into hepatocarcinoma cells, it was found to be severely impaired in its ability to produce infectious viruses in spite of its robust RNA genome replication. Taken together, all these results suggest an essential requirement of HCV core-JAK protein interaction for efficient production of infectious viruses and the potential of using core-JAK blockers as a new anti-HCV therapy. PMID:24009866

  17. Activated STAT5 proteins induce activation of the PI 3-kinase/Akt and Ras/MAPK pathways via the Gab2 scaffolding adapter.

    PubMed

    Nyga, Rémy; Pecquet, Christian; Harir, Noria; Gu, Haihua; Dhennin-Duthille, Isabelle; Régnier, Aline; Gouilleux-Gruart, Valérie; Lassoued, Kaïss; Gouilleux, Fabrice

    2005-08-15

    The active forms of STAT5A (signal transducer and activator of transcription 5A) and STAT5B are able to relieve the cytokine dependence of haematopoietic cells and to induce leukaemia in mice. We have demonstrated previously that activation of the PI3K (phosphoinositide 3-kinase) signalling cascade plays a major role in cell growth and survival induced by these proteins. Interaction between STAT5 and p85, the regulatory subunit of the PI3K, has been suggested to be required for this activation. We show in the present study that the scaffolding protein Gab2 [Grb2 (growth-factor-receptor-bound protein 2)-associated binder-2] is an essential component of this interaction. Gab2 is persistently tyrosine-phosphorylated in Ba/F3 cells expressing caSTAT5 (constitutively activated STAT5), independent of JAK2 (Janus kinase 2) activation where it interacts with STAT5, p85 and Grb2, but not with Shp2 [SH2 (Src homology 2)-domain-containing tyrosine phosphatase] proteins. Interaction of STAT5 with Gab2 was also observed in Ba/F3 cells stimulated with interleukin-3 or expressing the oncogenic fusion protein Tel-JAK2. The MAPKs (mitogen-activated protein kinases) ERK1 (extracellular-signal-regulated kinase 1) and ERK2 were constitutively activated in the caSTAT5-expressing cells and were found to be required for caSTAT5-induced cell proliferation. Overexpression of Gab2-3YF, a mutant of Gab2 incapable of binding PI3K, inhibited the proliferation and survival of caSTAT5-expressing cells as well as ERK1/2 and Akt/protein kinase B phosphorylation. Taken together, our results indicate that Gab2 is required for caSTAT5-induced cell proliferation by regulating both the PI3K/Akt and the Ras/MAPK pathways.

  18. Activated STAT5 proteins induce activation of the PI 3-kinase/Akt and Ras/MAPK pathways via the Gab2 scaffolding adapter

    PubMed Central

    2005-01-01

    The active forms of STAT5A (signal transducer and activator of transcription 5A) and STAT5B are able to relieve the cytokine dependence of haematopoietic cells and to induce leukaemia in mice. We have demonstrated previously that activation of the PI3K (phosphoinositide 3-kinase) signalling cascade plays a major role in cell growth and survival induced by these proteins. Interaction between STAT5 and p85, the regulatory subunit of the PI3K, has been suggested to be required for this activation. We show in the present study that the scaffolding protein Gab2 [Grb2 (growth-factor-receptor-bound protein 2)-associated binder-2] is an essential component of this interaction. Gab2 is persistently tyrosine-phosphorylated in Ba/F3 cells expressing caSTAT5 (constitutively activated STAT5), independent of JAK2 (Janus kinase 2) activation where it interacts with STAT5, p85 and Grb2, but not with Shp2 [SH2 (Src homology 2)-domain-containing tyrosine phosphatase] proteins. Interaction of STAT5 with Gab2 was also observed in Ba/F3 cells stimulated with interleukin-3 or expressing the oncogenic fusion protein Tel–JAK2. The MAPKs (mitogen-activated protein kinases) ERK1 (extracellular-signal-regulated kinase 1) and ERK2 were constitutively activated in the caSTAT5-expressing cells and were found to be required for caSTAT5-induced cell proliferation. Overexpression of Gab2-3YF, a mutant of Gab2 incapable of binding PI3K, inhibited the proliferation and survival of caSTAT5-expressing cells as well as ERK1/2 and Akt/protein kinase B phosphorylation. Taken together, our results indicate that Gab2 is required for caSTAT5-induced cell proliferation by regulating both the PI3K/Akt and the Ras/MAPK pathways. PMID:15833084

  19. Signaling network of the Btk family kinases.

    PubMed

    Qiu, Y; Kung, H J

    2000-11-20

    The Btk family kinases represent new members of non-receptor tyrosine kinases, which include Btk/Atk, Itk/Emt/Tsk, Bmx/Etk, and Tec. They are characterized by having four structural modules: PH (pleckstrin homology) domain, SH3 (Src homology 3) domain, SH2 (Src homology 2) domain and kinase (Src homology 1) domain. Increasing evidence suggests that, like Src-family kinases, Btk family kinases play central but diverse modulatory roles in various cellular processes. They participate in signal transduction in response to virtually all types of extracellular stimuli which are transmitted by growth factor receptors, cytokine receptors, G-protein coupled receptors, antigen-receptors and integrins. They are regulated by many non-receptor tyrosine kinases such as Src, Jak, Syk and FAK family kinases. In turn, they regulate many of major signaling pathways including those of PI3K, PLCgamma and PKC. Both genetic and biochemical approaches have been used to dissect the signaling pathways and elucidate their roles in growth, differentiation and apoptosis. An emerging new role of this family of kinases is cytoskeletal reorganization and cell motility. The physiological importance of these kinases was amply demonstrated by their link to the development of immunodeficiency diseases, due to germ-line mutations. The present article attempts to review the structure and functions of Btk family kinases by summarizing our current knowledge on the interacting partners associated with the different modules of the kinases and the diverse signaling pathways in which they are involved.

  20. The Possible Crosstalk of MOB2 With NDR1/2 Kinases in Cell Cycle and DNA Damage Signaling.

    PubMed

    Gundogdu, Ramazan; Hergovich, Alexander

    2016-09-06

    This article is the authors' opinion of the roles of the signal transducer Mps one binder 2 (MOB2) in the control of cell cycle progression and the DNA Damage Response (DDR). We recently found that endogenous MOB2 is required to prevent the accumulation of endogenous DNA damage in order to prevent the undesired, and possibly detrimental, activation of cell cycle checkpoints. In this regard, it is noteworthy that MOB2 has been linked biochemically to the regulation of the NDR1/2 (aka STK38/STK38L) protein kinases, which themselves have functions at different steps of the cell cycle. Therefore, we are speculating in this article about the possible connections of MOB2 with NDR1/2 kinases in cell cycle and DDR Signaling.

  1. Defocused low-energy shock wave activates adipose tissue-derived stem cells in vitro via multiple signaling pathways.

    PubMed

    Xu, Lina; Zhao, Yong; Wang, Muwen; Song, Wei; Li, Bo; Liu, Wei; Jin, Xunbo; Zhang, Haiyang

    2016-12-01

    We found defocused low-energy shock wave (DLSW) could be applied in regenerative medicine by activating mesenchymal stromal cells. However, the possible signaling pathways that participated in this process remain unknown. In the present study, DLSW was applied in cultured rat adipose tissue-derived stem cells (ADSCs) to explore its effect on ADSCs and the activated signaling pathways. After treating with DLSW, the cellular morphology and cytoskeleton of ADSCs were observed. The secretions of ADSCs were detected. The expressions of ADSC surface antigens were analyzed using flow cytometry. The expressions of proliferating cell nuclear antigen and Ki67 were analyzed using western blot. The expression of CXCR2 and the migrations of ADSCs in vitro and in vivo were detected. The phosphorylation of selected signaling pathways with or without inhibitors was also detected. DLSW did not change the morphology and phenotype of ADSCs, and could promote the secretion, proliferation and migration of ADSCs. The phosphorylation levels were significantly higher in mitogen-activated protein kinases (MAPK) pathway, phosphoinositide 3-kinase (PI-3K)/AKT pathway and nuclear factor-kappa B (NF-κB) signaling pathway but not in Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway. Furthermore, ADSCs were not activated by DLSW after adding the inhibitors of these pathways simultaneously. Our results demonstrated for the first time that DLSW could activate ADSCs through MAPK, PI-3K/AKT and NF-κB signaling pathways. Combination of DLSW and agonists targeting these pathways might improve the efficacy of ADSCs in regenerative medicine in the future. Copyright © 2016 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  2. Cartilage preservation by inhibition of Janus kinase 3 in two rodent models of rheumatoid arthritis

    PubMed Central

    Milici, Anthony J; Kudlacz, Elizabeth M; Audoly, Laurent; Zwillich, Samuel; Changelian, Paul

    2008-01-01

    Introduction CP-690550 is a small molecule inhibitor of Janus kinase 3 (JAK3), a critical enzyme in the signaling pathway of multiple cytokines (interleukin (IL)-2, -7, -15 and -21) that are important in various T cell functions including development, activation and homeostasis. The purpose of this study was to evaluate CP-690550 in murine collagen-induced (CIA) and rat adjuvant-induced (AA) models of rheumatoid arthritis (RA). Methods CIA and AA were induced using standard protocols and animals received the JAK3 inhibitor via osmotic mini-pump infusion at doses ranging from 1.5–15 mg/kg/day following disease induction. Arthritis was assessed by clinical scores in the CIA models and paw swelling monitored using a plethysmometer in the AA model until study conclusion, at which time animals were killed and evaluated histologically. Results CP-690550 dose-dependently decreased endpoints of disease in both RA models with greater than 90% reduction observed at the highest administered dose. An approximate ED50 of approximately 1.5 mg/kg/day was determined for the compound based upon disease endpoints in both RA models examined and corresponds to CP-690550 serum levels of 5.8 ng/ml in mice (day 28) and 24 ng/ml in rats (day 24). The compound also reduced inflammatory cell influx and joint damage as measured histologically. Animals receiving a CP-690550 dose of 15 mg/k/d showed no histological evidence of disease. Conclusion The efficacy observed with CP-690550 in CIA and AA suggests JAK3 inhibition may represent a novel therapeutic target for the treatment of RA. PMID:18234077

  3. Lumpy Janus

    NASA Image and Video Library

    2013-07-01

    The Cassini spacecraft catches a glimpse of Janus, an irregularly shaped moon. Lacking sufficient gravity to pull itself into a round shape, Janus has had its lumpy primordial shape only slightly modified by impacts since its formation.

  4. Oncogenic signaling by Kit tyrosine kinase occurs selectively on the Golgi apparatus in gastrointestinal stromal tumors

    PubMed Central

    Obata, Y; Horikawa, K; Takahashi, T; Akieda, Y; Tsujimoto, M; Fletcher, J A; Esumi, H; Nishida, T; Abe, R

    2017-01-01

    Gastrointestinal stromal tumors (GISTs) are caused by gain-of-function mutations in the Kit receptor tyrosine kinase. Most primary GIST patients respond to the Kit inhibitor imatinib, but this drug often becomes ineffective because of secondary mutations in the Kit kinase domain. The characteristic intracellular accumulation of imatinib-sensitive and -resistant Kit protein is well documented, but its relationship to oncogenic signaling remains unknown. Here, we show that in cancer tissue from primary GIST patients as well as in cell lines, mutant Kit accumulates on the Golgi apparatus, whereas normal Kit localizes to the plasma membrane (PM). In imatinib-resistant GIST with a secondary Kit mutation, Kit localizes predominantly on the Golgi apparatus. Both imatinib-sensitive and imatinib-resistant Kit (Kit(mut)) become fully auto-phosphorylated only on the Golgi and only if in a complex-glycosylated form. Kit(mut) accumulates on the Golgi during the early secretory pathway, but not after endocytosis. The aberrant kinase activity of Kit(mut) prevents its export from the Golgi to the PM. Furthermore, Kit(mut) on the Golgi signals and activates the phosphatidylinositol 3-kinase–Akt (PI3K–Akt) pathway, signal transducer and activator of transcription 5 (STAT5), and the Mek–Erk pathway. Blocking the biosynthetic transport of Kit(mut) to the Golgi from the endoplasmic reticulum inhibits oncogenic signaling. PM localization of Kit(mut) is not required for its signaling. Activation of Src-family tyrosine kinases on the Golgi is essential for oncogenic Kit signaling. These results suggest that the Golgi apparatus serves as a platform for oncogenic Kit signaling. Our study demonstrates that Kit(mut)’s pathogenicity is related to its mis-localization, and may offer a new strategy for treating imatinib-resistant GISTs. PMID:28192400

  5. OsCERK1-Mediated Chitin Perception and Immune Signaling Requires Receptor-like Cytoplasmic Kinase 185 to Activate an MAPK Cascade in Rice.

    PubMed

    Wang, Chao; Wang, Gang; Zhang, Chi; Zhu, Pinkuan; Dai, Huiling; Yu, Nan; He, Zuhua; Xu, Ling; Wang, Ertao

    2017-04-03

    Conserved pathogen-associated molecular patterns (PAMPs), such as chitin, are perceived by pattern recognition receptors (PRRs) located at the host cell surface and trigger rapid activation of mitogen-activated protein kinase (MAPK) cascades, which are required for plant resistance to pathogens. However, the direct links from PAMP perception to MAPK activation in plants remain largely unknown. In this study, we found that the PRR-associated receptor-like cytoplasmic kinase Oryza sativa RLCK185 transmits immune signaling from the PAMP receptor OsCERK1 to an MAPK signaling cascade through interaction with an MAPK kinase kinase, OsMAPKKKε, which is the initial kinase of the MAPK cascade. OsRLCK185 interacts with and phosphorylates the C-terminal regulatory domain of OsMAPKKKε. Coexpression of phosphomimetic OsRLCK185 and OsMAPKKKε activates MAPK3/6 phosphorylation in Nicotiana benthamiana leaves. Moreover, OsMAPKKKε interacts with and phosphorylates OsMKK4, a key MAPK kinase that transduces the chitin signal. Overexpression of OsMAPKKKε increases chitin-induced MAPK3/6 activation, whereas OsMAPKKKε knockdown compromises chitin-induced MAPK3/6 activation and resistance to rice blast fungus. Taken together, our results suggest the existence of a phospho-signaling pathway from cell surface chitin perception to intracellular activation of an MAPK cascade in rice. Copyright © 2017 The Author. Published by Elsevier Inc. All rights reserved.

  6. Human GH Receptor-IGF-1 Receptor Interaction: Implications for GH Signaling

    PubMed Central

    Gan, Yujun; Buckels, Ashiya; Liu, Ying; Zhang, Yue; Paterson, Andrew J.; Jiang, Jing; Zinn, Kurt R.

    2014-01-01

    GH signaling yields multiple anabolic and metabolic effects. GH binds the transmembrane GH receptor (GHR) to activate the intracellular GHR-associated tyrosine kinase, Janus kinase 2 (JAK2), and downstream signals, including signal transducer and activator of transcription 5 (STAT5) activation and IGF-1 gene expression. Some GH effects are partly mediated by GH-induced IGF-1 via IGF-1 receptor (IGF-1R), a tyrosine kinase receptor. We previously demonstrated in non-human cells that GH causes formation of a GHR-JAK2-IGF-1R complex and that presence of IGF-1R (even without IGF-1 binding) augments proximal GH signaling. In this study, we use human LNCaP prostate cancer cells as a model system to further study the IGF-1R's role in GH signaling. GH promoted JAK2 and GHR tyrosine phosphorylation and STAT5 activation in LNCaP cells. By coimmunoprecipitation and a new split luciferase complementation assay, we find that GH augments GHR/IGF-1R complex formation, which is inhibited by a Fab of an antagonistic anti-GHR monoclonal antibody. Short hairpin RNA-mediated IGF-1R silencing in LNCaP cells reduced GH-induced GHR, JAK2, and STAT5 phosphorylation. Similarly, a soluble IGF-1R extracellular domain fragment (sol IGF-1R) interacts with GHR in response to GH and blunts GH signaling. Sol IGF-1R also markedly inhibits GH-induced IGF-1 gene expression in both LNCaP cells and mouse primary osteoblast cells. On the basis of these and other findings, we propose a model in which IGF-1R augments GH signaling by allowing a putative IGF-1R-associated molecule that regulates GH signaling to access the activated GHR/JAK2 complex and envision sol IGF-1R as a dominant-negative inhibitor of this IGF-1R-mediated augmentation. Physiological implications of this new model are discussed. PMID:25211187

  7. Expression of the JAK/STAT Signaling Pathway in Bullous Pemphigoid and Dermatitis Herpetiformis

    PubMed Central

    Wozniacka, A.; Waszczykowska, E.; Zebrowska, A.

    2017-01-01

    A family of eleven proteins comprises the Janus kinases (JAK) and signal transducers and activators of transcription (STAT) signaling pathway, which enables transduction of signal from cytokine receptor to the nucleus and activation of transcription of target genes. Irregular functioning of the cascade may contribute to pathogenesis of autoimmune diseases; however, there are no reports concerning autoimmune bullous diseases yet to be published. The aim of this study was to evaluate the expression of proteins constituting the JAK/STAT signaling pathway in skin lesions and perilesional area in dermatitis herpetiformis (DH) and bullous pemphigoid (BP), as well as in the control group. Skin biopsies were collected from 21 DH patients, from 20 BP patients, and from 10 healthy volunteers. The localization and expression of selected STAT and JAK proteins were examined by immunohistochemistry and immunoblotting. We found significantly higher expression of JAK/STAT proteins in skin lesions in patients with BP and DH, in comparison to perilesional skin and the control group, which may be related to proinflammatory cytokine network and induction of inflammatory infiltrate in tissues. Our findings suggest that differences in the JAK and STAT expression may be related to distinct cytokines activating them and mediating neutrophilic and/or eosinophilic infiltrate. PMID:29203970

  8. Long-chain bases, phosphatidic acid, MAPKs, and reactive oxygen species as nodal signal transducers in stress responses in Arabidopsis

    PubMed Central

    Saucedo-García, Mariana; Gavilanes-Ruíz, Marina; Arce-Cervantes, Oscar

    2015-01-01

    Due to their sessile condition, plants have developed sensitive, fast, and effective ways to contend with environmental changes. These mechanisms operate as informational wires conforming extensive and intricate networks that are connected in several points. The responses are designed as pathways orchestrated by molecules that are transducers of protein and non-protein nature. Their chemical nature imposes selective features such as specificity, formation rate, and generation site to the informational routes. Enzymes such as mitogen-activated protein kinases and non-protein, smaller molecules, such as long-chain bases, phosphatidic acid, and reactive oxygen species are recurrent transducers in the pleiotropic responses to biotic and abiotic stresses in plants. In this review, we considered these four components as nodal points of converging signaling pathways that start from very diverse stimuli and evoke very different responses. These pleiotropic effects may be explained by the potentiality that every one of these four mediators can be expressed from different sources, cellular location, temporality, or magnitude. Here, we review recent advances in our understanding of the interplay of these four specific signaling components in Arabidopsis cells, with an emphasis on drought, cold and pathogen stresses. PMID:25763001

  9. LIF-activated Jak signaling determines Esrrb expression during late-stage reprogramming

    PubMed Central

    Huang, Delun; Wang, Ling; Duan, Jingyue; Huang, Chang; Tian, Xiuchun (Cindy); Zhang, Ming

    2018-01-01

    ABSTRACT The regulatory process of naïve-state induced pluripotent stem cell (iPSC) generation is not well understood. Leukemia inhibitory factor (LIF)-activated Janus kinase/signal transducer and activator of transcription 3 (Jak/Stat3) is the master regulator for naïve-state pluripotency achievement and maintenance. The estrogen-related receptor beta (Esrrb) serves as a naïve-state marker gene regulating self-renewal of embryonic stem cells (ESCs). However, the interconnection between Esrrb and LIF signaling for pluripotency establishment in reprogramming is unclear. We screened the marker genes critical for complete reprogramming during mouse iPSC generation, and identified genes including Esrrb that are responsive to LIF/Jak pathway signaling. Overexpression of Esrrb resumes the reprogramming halted by inhibition of Jak activity in partially reprogrammed cells (pre-iPSCs), and leads to the generation of pluripotent iPSCs. We further show that neither overexpression of Nanog nor stimulation of Wnt signaling, two upstream regulators of Esrrb in ESCs, stimulates the expression of Esrrb in reprogramming when LIF or Jak activity is blocked. Our study demonstrates that Esrrb is a specific reprogramming factor regulated downstream of the LIF/Jak signaling pathway. These results shed new light on the regulatory role of LIF pathway on complete pluripotency establishment during iPSC generation. PMID:29212799

  10. Endothelial Cell Proteomic Response to Rickettsia conorii Infection Reveals Activation of the Janus Kinase (JAK)-Signal Transducer and Activator of Transcription (STAT)-Inferferon Stimulated Gene (ISG)15 Pathway and Reprogramming Plasma Membrane Integrin/Cadherin Signaling.

    PubMed

    Zhao, Yingxin; Valbuena, Gustavo; Walker, David H; Gazi, Michal; Hidalgo, Marylin; DeSousa, Rita; Oteo, Jose Antonio; Goez, Yenny; Brasier, Allan R

    2016-01-01

    Rickettsia conorii is the etiologic agent of Mediterranean spotted fever, a re-emerging infectious disease with significant mortality. This Gram-negative, obligately intracellular pathogen is transmitted via tick bites, resulting in disseminated vascular endothelial cell infection with vascular leakage. In the infected human, Rickettsia conorii infects endothelial cells, stimulating expression of cytokines and pro-coagulant factors. However, the integrated proteomic response of human endothelial cells to R. conorii infection is not known. In this study, we performed quantitative proteomic profiling of primary human umbilical vein endothelial cells (HUVECs) with established R conorii infection versus those stimulated with endotoxin (LPS) alone. We observed differential expression of 55 proteins in HUVEC whole cell lysates. Of these, we observed induction of signal transducer and activator of transcription (STAT)1, MX dynamin-like GTPase (MX1), and ISG15 ubiquitin-like modifier, indicating activation of the JAK-STAT signaling pathway occurs in R. conorii-infected HUVECs. The down-regulated proteins included those involved in the pyrimidine and arginine biosynthetic pathways. A highly specific biotinylated cross-linking enrichment protocol was performed to identify dysregulation of 11 integral plasma membrane proteins that included up-regulated expression of a sodium/potassium transporter and down-regulation of α-actin 1. Analysis of Golgi and soluble Golgi fractions identified up-regulated proteins involved in platelet-endothelial adhesion, phospholipase activity, and IFN activity. Thirty four rickettsial proteins were identified with high confidence in the Golgi, plasma membrane, or secreted protein fractions. The host proteins associated with rickettsial infections indicate activation of interferon-STAT signaling pathways; the disruption of cellular adhesion and alteration of antigen presentation pathways in response to rickettsial infections are distinct from

  11. Auto-positioning ultrasonic transducer system

    NASA Technical Reports Server (NTRS)

    Buchanan, Randy K. (Inventor)

    2010-01-01

    An ultrasonic transducer apparatus and process for determining the optimal transducer position for flow measurement along a conduit outer surface. The apparatus includes a transmitting transducer for transmitting an ultrasonic signal, said transducer affixed to a conduit outer surface; a guide rail attached to a receiving transducer for guiding movement of a receiving transducer along the conduit outer surface, wherein the receiving transducer receives an ultrasonic signal from the transmitting transducer and sends a signal to a data acquisition system; and a motor for moving the receiving transducer along the guide rail, wherein the motor is controlled by a controller. The method includes affixing a transmitting transducer to an outer surface of a conduit; moving a receiving transducer on the conduit outer surface, wherein the receiving transducer is moved along a guide rail by a motor; transmitting an ultrasonic signal from the transmitting transducer that is received by the receiving transducer; communicating the signal received by the receiving transducer to a data acquisition and control system; and repeating the moving, transmitting, and communicating along a length of the conduit.

  12. The Pim kinases: new targets for drug development.

    PubMed

    Swords, Ronan; Kelly, Kevin; Carew, Jennifer; Nawrocki, Stefan; Mahalingam, Devalingam; Sarantopoulos, John; Bearss, David; Giles, Francis

    2011-12-01

    The three Pim kinases are a small family of serine/threonine kinases regulating several signaling pathways that are fundamental to cancer development and progression. They were first recognized as pro-viral integration sites for the Moloney Murine Leukemia virus. Unlike other kinases, they possess a hinge region which creates a unique binding pocket for ATP. Absence of a regulatory domain means that these proteins are constitutively active once transcribed. Pim kinases are critical downstream effectors of the ABL (ableson), JAK2 (janus kinase 2), and Flt-3 (FMS related tyrosine kinase 1) oncogenes and are required by them to drive tumorigenesis. Recent investigations have established that the Pim kinases function as effective inhibitors of apoptosis and when overexpressed, produce resistance to the mTOR (mammalian target of rapamycin) inhibitor, rapamycin . Overexpression of the PIM kinases has been reported in several hematological and solid tumors (PIM 1), myeloma, lymphoma, leukemia (PIM 2) and adenocarcinomas (PIM 3). As such, the Pim kinases are a very attractive target for pharmacological inhibition in cancer therapy. Novel small molecule inhibitors of the human Pim kinases have been designed and are currently undergoing preclinical evaluation.

  13. Hybrid Escherichia coli sensory transducers with altered stimulus detection and signaling properties.

    PubMed Central

    Slocum, M K; Halden, N F; Parkinson, J S

    1987-01-01

    The tar and tap loci of Escherichia coli encode methyl-accepting inner membrane proteins that mediate chemotactic responses to aspartate and maltose or to dipeptides. These genes lie adjacent to each other in the same orientation on the chromosome and have extensive sequence homology throughout the C-terminal portions of their coding regions. Many spontaneous deletions in the tar-tap region appear to be generated by recombination between these regions of homology, leading to gene fusions that produce hybrid transducer molecules in which the N terminus of Tar is joined to the C terminus of Tap. The properties of two such hybrids are described in this report. Although Tar and Tap molecules have homologous domain structures, these Tar-Tap hybrids exhibited defects in stimulus detection and flagellar signaling. Both hybrid transducers retained Tar receptor specificity, but had reduced detection sensitivity. This defect was correlated with the presence of the C-terminal methyl-accepting segment of Tap, which may have more methylation sites than its Tar counterpart, leading to elevated steady-state methylation levels in the hybrid molecules. One of the hybrids, which carried a more extensive segment from Tap, appeared to generate constitutive signals that locked the flagellar motors in a counterclockwise rotational mode. Changes in the methylation state of this transducer were ineffective in cancelling this aberrant signal. These findings implicate the conserved C-terminal domain of bacterial transducers in the generation or regulation of flagellar signals. Images PMID:3110130

  14. Janus-kinase-2 relates directly to portal hypertension and to complications in rodent and human cirrhosis.

    PubMed

    Klein, Sabine; Rick, Johanna; Lehmann, Jennifer; Schierwagen, Robert; Schierwagen, Irela Gretchen; Verbeke, Len; Hittatiya, Kanishka; Uschner, Frank Erhard; Manekeller, Steffen; Strassburg, Christian P; Wagner, Kay-Uwe; Sayeski, Peter P; Wolf, Dominik; Laleman, Wim; Sauerbruch, Tilman; Trebicka, Jonel

    2017-01-01

    Angiotensin II (AngII) activates via angiotensin-II-type-I receptor (AT1R) Janus-kinase-2 (JAK2)/Arhgef1 pathway and subsequently RHOA/Rho-kinase (ROCK), which induces experimental and probably human liver fibrosis. This study investigated the relationship of JAK2 to experimental and human portal hypertension. The mRNA and protein levels of JAK2/ARHGEF1 signalling components were analysed in 49 human liver samples and correlated with clinical parameters of portal hypertension in these patients. Correspondingly, liver fibrosis (bile duct ligation (BDL), carbon tetrachloride (CCl 4 )) was induced in floxed-Jak2 knock-out mice with SM22-promotor (SM22 Cre+ -Jak2 f/f ). Transcription and contraction of primary myofibroblasts from healthy and fibrotic mice and rats were analysed. In two different cirrhosis models (BDL, CCl 4 ) in rats, the acute haemodynamic effect of the JAK2 inhibitor AG490 was assessed using microsphere technique and isolated liver perfusion experiments. Hepatic transcription of JAK2/ARHGEF1 pathway components was upregulated in liver cirrhosis dependent on aetiology, severity and complications of human liver cirrhosis (Model for End-stage Liver disease (MELD) score, Child score as well as ascites, high-risk varices, spontaneous bacterial peritonitis). SM22 Cre+ - Jak2 f/f mice lacking Jak2 developed less fibrosis and lower portal pressure (PP) than SM22 Cre- -Jak2 f/f upon fibrosis induction. Myofibroblasts from SM22 Cre+ -Jak2 f/f mice expressed less collagen and profibrotic markers upon activation. AG490 relaxed activated hepatic stellate cells in vitro. In cirrhotic rats, AG490 decreased hepatic vascular resistance and consequently the PP in vivo and in situ. Hepatic JAK2/ARHGEF1/ROCK expression is associated with portal hypertension and decompensation in human cirrhosis. The deletion of Jak2 in myofibroblasts attenuated experimental fibrosis and acute inhibition of JAK2 decreased PP. Thus, JAK2 inhibitors, already in clinical use for other

  15. Cooperative unfolding of distinctive mechanoreceptor domains transduces force into signals

    PubMed Central

    Ju, Lining; Chen, Yunfeng; Xue, Lingzhou; Du, Xiaoping; Zhu, Cheng

    2016-01-01

    How cells sense their mechanical environment and transduce forces into biochemical signals is a crucial yet unresolved question in mechanobiology. Platelets use receptor glycoprotein Ib (GPIb), specifically its α subunit (GPIbα), to signal as they tether and translocate on von Willebrand factor (VWF) of injured arterial surfaces against blood flow. Force elicits catch bonds to slow VWF–GPIbα dissociation and unfolds the GPIbα leucine-rich repeat domain (LRRD) and juxtamembrane mechanosensitive domain (MSD). How these mechanical processes trigger biochemical signals remains unknown. Here we analyze these extracellular events and the resulting intracellular Ca2+ on a single platelet in real time, revealing that LRRD unfolding intensifies Ca2+ signal whereas MSD unfolding affects the type of Ca2+ signal. Therefore, LRRD and MSD are analog and digital force transducers, respectively. The >30 nm macroglycopeptide separating the two domains transmits force on the VWF–GPIbα bond (whose lifetime is prolonged by LRRD unfolding) to the MSD to enhance its unfolding, resulting in unfolding cooperativity at an optimal force. These elements may provide design principles for a generic mechanosensory protein machine. DOI: http://dx.doi.org/10.7554/eLife.15447.001 PMID:27434669

  16. The paradigm of IL-6: from basic science to medicine.

    PubMed

    Naka, Tetsuji; Nishimoto, Norihiro; Kishimoto, Tadamitsu

    2002-01-01

    IL-6 is a pleiotropic cytokine with a wide range of biological activities in immune regulation, hematopoiesis, inflammation, and oncogenesis. Its activities are shared by IL-6-related cytokines such as leukemia inhibitory factor and oncostatin M. The pleiotropy and redundancy of IL-6 functions have been identified by using a unique receptor system comprising two functional proteins: an IL-6 receptor (IL-6R) and gp130, the common signal transducer of cytokines related to IL-6. Signal transduction through gp130 is mediated by two pathways: the JAK-STAT (Janus family tyrosine kinase-signal transducer and activator of transcription) pathway and the Ras mitogen-activated protein kinase pathway. The negative regulators of IL-6 signaling have also been identified, although the physiological roles of the molecules are not yet fully understood. The pathological roles of IL-6 have also been clarified in various disease conditions, such as inflammatory, autoimmune, and malignant diseases. On the basis of the findings, a new therapeutic approach to block the IL-6 signal using humanized anti-IL-6R antibody for rheumatoid arthritis, Castleman's disease, and multiple myeloma has been attempted.

  17. p38 Mitogen-Activated Protein Kinase/Signal Transducer and Activator of Transcription-3 Pathway Signaling Regulates Expression of Inhibitory Molecules in T Cells Activated by HIV-1–Exposed Dendritic Cells

    PubMed Central

    Che, Karlhans Fru; Shankar, Esaki Muthu; Muthu, Sundaram; Zandi, Sasan; Sigvardsson, Mikael; Hinkula, Jorma; Messmer, Davorka; Larsson, Marie

    2012-01-01

    Human immunodeficiency virus type 1 (HIV-1) infection enhances the expression of inhibitory molecules on T cells, leading to T-cell impairment. The signaling pathways underlying the regulation of inhibitory molecules and subsequent onset of T-cell impairment remain elusive. We showed that both autologous and allogeneic T cells exposed to HIV-pulsed dendritic cells (DCs) upregulated cytotoxic T-lymphocyte antigen (CTLA-4), tumor-necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), lymphocyte-activation gene-3 (LAG3), T-cell immunoglobulin mucin-3 (TIM-3), CD160 and certain suppression-associated transcription factors, such as B-lymphocyte induced maturation protein-1 (BLIMP-1), deltex homolog 1 protein (DTX1) and forkhead box P3 (FOXP3), leading to T-cell suppression. This induction was regulated by p38 mitogen-activated protein kinase/signal transducer and activator of transcription-3 (P38MAPK/STAT3) pathways, because their blockade significantly abrogated expression of all the inhibitory molecules studied and a subsequent recovery in T-cell proliferation. Neither interleukin-6 (IL-6) nor IL-10 nor growth factors known to activate STAT3 signaling events were responsible for STAT3 activation. Involvement of the P38MAPK/STAT3 pathways was evident because these proteins had a higher level of phosphorylation in the HIV-1–primed cells. Furthermore, blockade of viral CD4 binding and fusion significantly reduced the negative effects DCs imposed on primed T cells. In conclusion, HIV-1 interaction with DCs modulated their functionality, causing them to trigger the activation of the P38MAPK/STAT3 pathway in T cells, which was responsible for the upregulation of inhibitory molecules. PMID:22777388

  18. Versatile logic devices based on programmable DNA-regulated silver-nanocluster signal transducers.

    PubMed

    Huang, Zhenzhen; Tao, Yu; Pu, Fang; Ren, Jinsong; Qu, Xiaogang

    2012-05-21

    A DNA-encoding strategy is reported for the programmable regulation of the fluorescence properties of silver nanoclusters (AgNCs). By taking advantage of the DNA-encoding strategy, aqueous AgNCs were used as signal transducers to convert DNA inputs into fluorescence outputs for the construction of various DNA-based logic gates (AND, OR, INHIBIT, XOR, NOR, XNOR, NAND, and a sequential logic gate). Moreover, a biomolecular keypad that was capable of constructing crossword puzzles was also fabricated. These AgNC-based logic systems showed several advantages, including a simple transducer-introduction strategy, universal design, and biocompatible operation. In addition, this proof of concept opens the door to a new generation of signal transducer materials and provides a general route to versatile biomolecular logic devices for practical applications. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. 21 CFR 870.2060 - Transducer signal amplifier and conditioner.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Transducer signal amplifier and conditioner. 870.2060 Section 870.2060 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2060...

  20. 21 CFR 870.2060 - Transducer signal amplifier and conditioner.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Transducer signal amplifier and conditioner. 870.2060 Section 870.2060 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2060...

  1. 21 CFR 870.2060 - Transducer signal amplifier and conditioner.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Transducer signal amplifier and conditioner. 870.2060 Section 870.2060 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2060...

  2. 21 CFR 870.2060 - Transducer signal amplifier and conditioner.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Transducer signal amplifier and conditioner. 870.2060 Section 870.2060 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2060...

  3. 21 CFR 870.2060 - Transducer signal amplifier and conditioner.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Transducer signal amplifier and conditioner. 870.2060 Section 870.2060 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2060...

  4. CYT387, a selective JAK1/JAK2 inhibitor: in vitro assessment of kinase selectivity and preclinical studies using cell lines and primary cells from polycythemia vera patients.

    PubMed

    Pardanani, A; Lasho, T; Smith, G; Burns, C J; Fantino, E; Tefferi, A

    2009-08-01

    Somatic mutations in Janus kinase 2 (JAK2), including JAK2V617F, result in dysregulated JAK-signal transducer and activator transcription (STAT) signaling, which is implicated in myeloproliferative neoplasm (MPN) pathogenesis. CYT387 is an ATP-competitive small molecule that potently inhibits JAK1/JAK2 kinases (IC(50)=11 and 18 nM, respectively), with significantly less activity against other kinases, including JAK3 (IC(50)=155 nM). CYT387 inhibits growth of Ba/F3-JAK2V617F and human erythroleukemia (HEL) cells (IC(50) approximately 1500 nM) or Ba/F3-MPLW515L cells (IC(50)=200 nM), but has considerably less activity against BCR-ABL harboring K562 cells (IC=58 000 nM). Cell lines harboring mutated JAK2 alleles (CHRF-288-11 or Ba/F3-TEL-JAK2) were inhibited more potently than the corresponding pair harboring mutated JAK3 alleles (CMK or Ba/F3-TEL-JAK3), and STAT-5 phosphorylation was inhibited in HEL cells with an IC(50)=400 nM. Furthermore, CYT387 selectively suppressed the in vitro growth of erythroid colonies harboring JAK2V617F from polycythemia vera (PV) patients, an effect that was attenuated by exogenous erythropoietin. Overall, our data indicate that the JAK1/JAK2 selective inhibitor CYT387 has potential for efficacious treatment of MPN harboring mutated JAK2 and MPL alleles.

  5. Targeted Blockage of Signal Transducer and Activator of Transcription 5 Signaling Pathway with Decoy Oligodeoxynucleotides Suppresses Leukemic K562 Cell Growth

    PubMed Central

    Wang, Xiaozhong; Zeng, Jianming; Shi, Mei; Zhao, Shiqiao; Bai, Weijun; Cao, Weixi; Tu, Zhiguang; Huang, Zonggan

    2011-01-01

    The protein signal transducer and activator of transcription 5 (STAT5) of the JAK/STAT pathway is constitutively activated because of its phosphorylation by tyrosine kinase activity of fusion protein BCR-ABL in chronic myelogenous leukemia (CML) cells. This study investigated the potential therapeutic effect of STAT5 decoy oligodeoxynucleotides (ODN) using leukemia K562 cells as a model. Our results showed that transfection of 21-mer-long STAT5 decoy ODN into K562 cells effectively inhibited cell proliferation and induced cell apoptosis. Further, STAT5 decoy ODN downregulated STAT5 targets bcl-xL, cyclinD1, and c-myc at both mRNA and protein levels in a sequence-specific manner. Collectively, these data demonstrate the therapeutic effect of blocking the STAT5 signal pathway by cis-element decoy for cancer characterized by constitutive STAT5 activation. Thus, our study provides support for STAT5 as a potential target downstream of BCR-ABL for CML treatment and helps establish the concept of targeting STAT5 by decoy ODN as a novel therapy approach for imatinib-resistant CML. PMID:21091189

  6. Targeting the tyrosine kinase signalling pathways for treatment of immune-mediated glomerulonephritis: from bench to bedside and beyond

    PubMed Central

    Ma, Terry King-Wing; McAdoo, Stephen P.

    2017-01-01

    Glomerulonephritis (GN) affects patients of all ages and is an important cause of morbidity and mortality. Non-selective immunosuppressive drugs have been used in immune-mediated GN but often result in systemic side effects and occasionally fatal infective complications. There is increasing evidence from both preclinical and clinical studies that abnormal activation of receptor and non-receptor tyrosine kinase signalling pathways are implicated in the pathogenesis of immune-mediated GN. Activation of spleen tyrosine kinase (SYK), Bruton's tyrosine kinase (BTK), platelet-derived growth factor receptor (PDGFR), epidermal growth factor receptor (EGFR) and discoidin domain receptor 1 (DDR1) have been demonstrated in anti-GBM disease. SYK is implicated in the pathogenesis of ANCA-associated GN. SYK, BTK, PDGFR, EFGR, DDR1 and Janus kinase are implicated in the pathogenesis of lupus nephritis. A representative animal model of IgA nephropathy (IgAN) is lacking. Based on the results from in vitro and human renal biopsy study results, a phase II clinical trial is ongoing to evaluate the efficacy and safety of fostamatinib (an oral SYK inhibitor) in high-risk IgAN patient. Various tyrosine kinase inhibitors (TKIs) have been approved for cancer treatment. Clinical trials of TKIs in GN may be justified given their long-term safety data. In this review we will discuss the current unmet medical needs in GN treatment and research as well as the current stage of development of TKIs in GN treatment and propose an accelerated translational research approach to investigate whether selective inhibition of tyrosine kinase provides a safer and more efficacious option for GN treatment. PMID:28391340

  7. Targeting the tyrosine kinase signalling pathways for treatment of immune-mediated glomerulonephritis: from bench to bedside and beyond.

    PubMed

    Ma, Terry King-Wing; McAdoo, Stephen P; Tam, Frederick Wai Keung

    2017-01-01

    Glomerulonephritis (GN) affects patients of all ages and is an important cause of morbidity and mortality. Non-selective immunosuppressive drugs have been used in immune-mediated GN but often result in systemic side effects and occasionally fatal infective complications. There is increasing evidence from both preclinical and clinical studies that abnormal activation of receptor and non-receptor tyrosine kinase signalling pathways are implicated in the pathogenesis of immune-mediated GN. Activation of spleen tyrosine kinase (SYK), Bruton's tyrosine kinase (BTK), platelet-derived growth factor receptor (PDGFR), epidermal growth factor receptor (EGFR) and discoidin domain receptor 1 (DDR1) have been demonstrated in anti-GBM disease. SYK is implicated in the pathogenesis of ANCA-associated GN. SYK, BTK, PDGFR, EFGR, DDR1 and Janus kinase are implicated in the pathogenesis of lupus nephritis. A representative animal model of IgA nephropathy (IgAN) is lacking. Based on the results from in vitro and human renal biopsy study results, a phase II clinical trial is ongoing to evaluate the efficacy and safety of fostamatinib (an oral SYK inhibitor) in high-risk IgAN patient. Various tyrosine kinase inhibitors (TKIs) have been approved for cancer treatment. Clinical trials of TKIs in GN may be justified given their long-term safety data. In this review we will discuss the current unmet medical needs in GN treatment and research as well as the current stage of development of TKIs in GN treatment and propose an accelerated translational research approach to investigate whether selective inhibition of tyrosine kinase provides a safer and more efficacious option for GN treatment. © The Author 2017. Published by Oxford University Press on behalf of ERA-EDTA.

  8. Long-term modulation of mitochondrial Ca2+ signals by protein kinase C isozymes

    PubMed Central

    Pinton, Paolo; Leo, Sara; Wieckowski, Mariusz R.; Di Benedetto, Giulietta; Rizzuto, Rosario

    2004-01-01

    The modulation of Ca2+ signaling patterns during repetitive stimulations represents an important mechanism for integrating through time the inputs received by a cell. By either overexpressing the isoforms of protein kinase C (PKC) or inhibiting them with specific blockers, we investigated the role of this family of proteins in regulating the dynamic interplay of the intracellular Ca2+ pools. The effects of the different isoforms spanned from the reduction of ER Ca2+ release (PKCα) to the increase or reduction of mitochondrial Ca2+ uptake (PKCζ and PKCβ/PKCδ, respectively). This PKC-dependent regulatory mechanism underlies the process of mitochondrial Ca2+ desensitization, which in turn modulates cellular responses (e.g., insulin secretion). These results demonstrate that organelle Ca2+ homeostasis (and in particular mitochondrial processing of Ca2+ signals) is tuned through the wide molecular repertoire of intracellular Ca2+ transducers. PMID:15096525

  9. Simvastatin prevents isoproterenol-induced cardiac hypertrophy through modulation of the JAK/STAT pathway

    PubMed Central

    Al-rasheed, Nouf M; Al-Oteibi, Maha M; Al-Manee, Reem Z; Al-shareef, Sarah A; Al-Rasheed, Nawal M; Hasan, Iman H; Mohamad, Raeesa A; Mahmoud, Ayman M

    2015-01-01

    Simvastatin (SIM) is a lipid-soluble inhibitor of hydroxy-3-methylglutaryl coenzyme A reductase with multiple reported therapeutic benefits. The present study was designed to investigate the effect of pretreatment with SIM on isoproterenol (ISO)-induced cardiac hypertrophy in rats. Twenty-four male albino Wistar rats weighing 180–200 g were divided into four groups. Groups I and III received normal saline while groups II and IV received SIM (10 mg/kg body weight) for 30 days per gavage. In the last 7 days, rats of groups III and IV were administered ISO (5 mg/kg) intraperitoneally to induce cardiac hypertrophy. Administration of ISO induced an increase in heart-to-body weight (HW/BW) ratio, an increase in serum interleukin-6, and elevated systolic and diastolic blood pressure. Serum levels of lipids, cardiovascular risk indices, and cardiac troponin I and creatine phosphokinase-MB showed significant increase in ISO-induced hypertrophic rats. Histopathological examination of heart tissue revealed focal areas of subendocardium degeneration, mononuclear cellular infiltrations, fibrous tissue deposition, and increased thickness of the myocardium of left ventricle. In addition, ISO-administered rats exhibited significant upregulation of cardiac Janus kinase, phosphorylated signal transducer and activator of transcription, and nuclear factor-kappa B. Pretreatment with SIM significantly prevented ISO-induced cardiac hypertrophy, alleviated the altered biochemical parameters, and improved the heart architecture. In conclusion, our study provides evidence that SIM prevented the development of cardiac hypertrophy via modulation of the Janus kinase/signal transducer and activator of transcription-signaling pathway in the heart of ISO-administered animals. PMID:26150695

  10. Simvastatin prevents isoproterenol-induced cardiac hypertrophy through modulation of the JAK/STAT pathway.

    PubMed

    Al-Rasheed, Nouf M; Al-Oteibi, Maha M; Al-Manee, Reem Z; Al-Shareef, Sarah A; Al-Rasheed, Nawal M; Hasan, Iman H; Mohamad, Raeesa A; Mahmoud, Ayman M

    2015-01-01

    Simvastatin (SIM) is a lipid-soluble inhibitor of hydroxy-3-methylglutaryl coenzyme A reductase with multiple reported therapeutic benefits. The present study was designed to investigate the effect of pretreatment with SIM on isoproterenol (ISO)-induced cardiac hypertrophy in rats. Twenty-four male albino Wistar rats weighing 180-200 g were divided into four groups. Groups I and III received normal saline while groups II and IV received SIM (10 mg/kg body weight) for 30 days per gavage. In the last 7 days, rats of groups III and IV were administered ISO (5 mg/kg) intraperitoneally to induce cardiac hypertrophy. Administration of ISO induced an increase in heart-to-body weight (HW/BW) ratio, an increase in serum interleukin-6, and elevated systolic and diastolic blood pressure. Serum levels of lipids, cardiovascular risk indices, and cardiac troponin I and creatine phosphokinase-MB showed significant increase in ISO-induced hypertrophic rats. Histopathological examination of heart tissue revealed focal areas of subendocardium degeneration, mononuclear cellular infiltrations, fibrous tissue deposition, and increased thickness of the myocardium of left ventricle. In addition, ISO-administered rats exhibited significant upregulation of cardiac Janus kinase, phosphorylated signal transducer and activator of transcription, and nuclear factor-kappa B. Pretreatment with SIM significantly prevented ISO-induced cardiac hypertrophy, alleviated the altered biochemical parameters, and improved the heart architecture. In conclusion, our study provides evidence that SIM prevented the development of cardiac hypertrophy via modulation of the Janus kinase/signal transducer and activator of transcription-signaling pathway in the heart of ISO-administered animals.

  11. STAT3 Activation in Pressure-Overloaded Feline Myocardium: Role for Integrins and the Tyrosine Kinase BMX

    PubMed Central

    Willey, Christopher D.; Palanisamy, Arun P.; Johnston, Rebecca K.; Mani, Santhosh K.; Shiraishi, Hirokazu; Tuxworth, William J.; Zile, Michael R.; Balasubramanian, Sundaravadivel; Kuppuswamy, Dhandapani

    2008-01-01

    Growth, survival and cytoskeletal rearrangement of cardiomyocytes are critical for cardiac hypertrophy. Signal transducer and activator of transcription-3 (STAT3) activation is an important cardioprotective factor associated with cardiac hypertrophy. Although STAT3 activation has been reported via signaling through Janus Kinase 2 (JAK2) in several cardiac models of hypertrophy, the importance of other nonreceptor tyrosine kinases (NTKs) has not been explored. Utilizing an in vivo feline right ventricular pressure-overload (RVPO) model of hypertrophy, we demonstrate that in 48 h pressure-overload (PO) myocardium, STAT3 becomes phosphorylated and redistributed to detergent-insoluble fractions with no accompanying JAK2 activation. PO also caused increased levels of phosphorylated STAT3 in both cytoplasmic and nuclear fractions. To investigate the role of other NTKs, we used our established in vitro cell culture model of hypertrophy where adult feline cardiomyocytes are embedded three-dimensionally (3D) in type-I collagen and stimulated with an integrin binding peptide containing an Arg-Gly-Asp (RGD) motif that we have previously shown to recapitulate the focal adhesion complex (FAC) formation of 48 h RVPO. RGD stimulation of adult cardiomyocytes in vitro caused both STAT3 redistribution and activation that were accompanied by the activation and redistribution of c-Src and the TEC family kinase, BMX, but not JAK2. However, infection with dominant negative c-Src adenovirus was unable to block RGD-stimulated changes on either STAT3 or BMX. Further analysis in vivo in 48 h PO myocardium showed the presence of both STAT3 and BMX in the detergent-insoluble fraction with their complex formation and phosphorylation. Therefore, these studies indicate a novel mechanism of BMX-mediated STAT3 activation within a PO model of cardiac hypertrophy that might contribute to cardiomyocyte growth and survival. PMID:18612371

  12. STAT3 activation in pressure-overloaded feline myocardium: role for integrins and the tyrosine kinase BMX.

    PubMed

    Willey, Christopher D; Palanisamy, Arun P; Johnston, Rebecca K; Mani, Santhosh K; Shiraishi, Hirokazu; Tuxworth, William J; Zile, Michael R; Balasubramanian, Sundaravadivel; Kuppuswamy, Dhandapani

    2008-06-27

    Growth, survival and cytoskeletal rearrangement of cardiomyocytes are critical for cardiac hypertrophy. Signal transducer and activator of transcription-3 (STAT3) activation is an important cardioprotective factor associated with cardiac hypertrophy. Although STAT3 activation has been reported via signaling through Janus Kinase 2 (JAK2) in several cardiac models of hypertrophy, the importance of other nonreceptor tyrosine kinases (NTKs) has not been explored. Utilizing an in vivo feline right ventricular pressure-overload (RVPO) model of hypertrophy, we demonstrate that in 48 h pressure-overload (PO) myocardium, STAT3 becomes phosphorylated and redistributed to detergent-insoluble fractions with no accompanying JAK2 activation. PO also caused increased levels of phosphorylated STAT3 in both cytoplasmic and nuclear fractions. To investigate the role of other NTKs, we used our established in vitro cell culture model of hypertrophy where adult feline cardiomyocytes are embedded three-dimensionally (3D) in type-I collagen and stimulated with an integrin binding peptide containing an Arg-Gly-Asp (RGD) motif that we have previously shown to recapitulate the focal adhesion complex (FAC) formation of 48 h RVPO. RGD stimulation of adult cardiomyocytes in vitro caused both STAT3 redistribution and activation that were accompanied by the activation and redistribution of c-Src and the TEC family kinase, BMX, but not JAK2. However, infection with dominant negative c-Src adenovirus was unable to block RGD-stimulated changes on either STAT3 or BMX. Further analysis in vivo in 48 h PO myocardium showed the presence of both STAT3 and BMX in the detergent-insoluble fraction with their complex formation and phosphorylation. Therefore, these studies indicate a novel mechanism of BMX-mediated STAT3 activation within a PO model of cardiac hypertrophy that might contribute to cardiomyocyte growth and survival.

  13. Janus Stands Alone

    NASA Image and Video Library

    2015-05-18

    Although Janus should be the least lonely of all moons -- sharing its orbit with Epimetheus -- it still spends most of its orbit far from other moons, alone in the vastness of space. Janus (111 miles or 179 kilometers across) and Epimetheus have the same average distance from Saturn, but they take turns being a little closer or a little farther from Saturn, swapping positions approximately every 4 years. See PIA08348 for more. This view looks toward the sunlit side of the rings from about 19 degrees above the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Feb. 4, 2015. The view was acquired at a distance of approximately 1.6 million miles (2.5 million kilometers) from Janus and at a Sun-Janus-spacecraft, or phase, angle of 91 degrees. Image scale is 9 miles (15 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/pia18315

  14. Identification of myristoylated alanine-rich C kinase substrate (MARCKS) in astrocytes.

    PubMed

    Vitkovic, Ljubisa; Aloyo, Vincent J; Maeda, Shigeru; Benzil, Deborha L; Bressler, Joseph P; Hilt, Dana C

    2005-01-01

    We have characterized membrane-associated substrates of Ca2+-dependent kinases in primary rat astrocytes by in vitro phosphorylation, 2-dimensional gel electrophoresis and autoradiography. The most prominent among these were three acidic, protein kinase C (PKC) substrates. These are important because they likely transduce cytokine and other neuro-immune modulatory signals mediated by PKC. We now show that one of these phosphoproteins is myristoylated alanine-rich PKC kinase substrate (MARCKS) or phosphomyristin C. The identity was corroborated by one- and 2- dimensional immunoblotting with an MARCKS-specific polyclonal antibody. Exposing primary astrocytes to phorbol 12-myristate 13-acetate stimulated phosphorylation of this protein. The level of MARCKS appeared inversely proportional to the proliferative potential of astrocytes because it was lower in spontaneously transformed as compared to passaged or confluent cells. These data are consistent with previous reports and indicate that one of three major acidic membrane-associated PKC substrates in astrocytes is MARCKS. Thus, MARCKS is likely near-proximal transducer of PKC-mediated signals in astrocytes.

  15. Cholinergic and cytoprotective signaling cascades mediate the mitigative effect of erythropoietin on acute radiation syndrome.

    PubMed

    Galal, Shereen Mohamed; Abdel-Rafei, Mohamed Khairy; Hasan, Hesham Farouk

    2018-05-01

    The present investigation aimed to evaluate the radiomitigative efficacy of the recombinant human erythropoietin (EPO) against acute radiation syndrome (ARS) in a rat model. Rats were irradiated with a single sublethal dose of γ-radiation (7 Gy; total body irradiation; TBI) on the 1st day of experimental course, then received EPO (5000 IU/kg; i.p.) 24 h after irradiation, and rats were observed for 30 days of survival analysis. Administration of EPO improved 30-day survival, alleviated TBI-induced myelosuppression and pancytopenia, by augmenting lymphocytes and other white blood cells in the peripheral blood of rats, while bone marrow and spleen cellularity were restored. EPO post-exposure treatment alleviated hepatotoxicity biomarkers and restored splenic function. EPO abrogated radiation-induced oxidative stress through the upregulation of the cholinergic anti-inflammatory nicotinic acetylcholine receptor (α-7-nAChR) and the pro-survival Janus kinase-2 and signal transducers and activators of transcription JAK-2/STAT-3 signaling mediated via enhancing nuclear factor erythroid-2 related factor-2 (Nrf-2) cytoprotective machinery in liver and spleen of irradiated rats. Moreover, EPO treatment prevented hepatic and splenic apoptosis. The present study establishes the implication of α-7-nAChR-JAK-2/STAT-3-Nrf-2 signaling cascade in the radiomitigative potential of EPO against ARS.

  16. Janus kinase inhibitors for the treatment of inflammatory bowel diseases: developments from phase I and phase II clinical trials.

    PubMed

    D'Amico, Ferdinando; Fiorino, Gionata; Furfaro, Federica; Allocca, Mariangela; Danese, Silvio

    2018-06-23

    A new pharmacological class, janus kinases (JAK) inhibitors, has been shown to be effective and safe for the treatment of inflammatory bowel diseases (IBD). The aim of this review is to provide an overview of the JAK inhibitors currently under investigation in phase I and II clinical trials for patients with Crohn's disease (CD) and ulcerative colitis (UC), and the possible future perspectives for the treatment of IBD patients with this class of drugs. Areas covered: This review describes the JAK-STAT pathway and analyzes the efficacy and safety of new small molecules such as filgotinib, upadacitinib, TD-1473, peficitinib and Pf-06651600/Pf-06700841, showing data from phase I and II trials. Expert Opinion: JAK inhibitors, if approved by the regulatory authorities, could represent a novel and intriguing drug class. In the next years the approach to patients with IBD will become increasingly personalized.

  17. Signal-transducing protein phosphorylation cascades mediated by Ras/Rho proteins in the mammalian cell: the potential for multiplex signalling.

    PubMed Central

    Denhardt, D T

    1996-01-01

    The features of three distinct protein phosphorylation cascades in mammalian cells are becoming clear. These signalling pathways link receptor-mediated events at the cell surface or intracellular perturbations such as DNA damage to changes in cytoskeletal structure, vesicle transport and altered transcription factor activity. The best known pathway, the Ras-->Raf-->MEK-->ERK cascade [where ERK is extracellular-signal-regulated kinase and MEK is mitogen-activated protein (MAP) kinase/ERK kinase], is typically stimulated strongly by mitogens and growth factors. The other two pathways, stimulated primarily by assorted cytokines, hormones and various forms of stress, predominantly utilize p21 proteins of the Rho family (Rho, Rac and CDC42), although Ras can also participate. Diagnostic of each pathway is the MAP kinase component, which is phosphorylated by a unique dual-specificity kinase on both tyrosine and threonine in one of three motifs (Thr-Glu-Tyr, Thr-Phe-Tyr or Thr-Gly-Tyr), depending upon the pathway. In addition to activating one or more protein phosphorylation cascades, the initiating stimulus may also mobilize a variety of other signalling molecules (e.g. protein kinase C isoforms, phospholipid kinases, G-protein alpha and beta gamma subunits, phospholipases, intracellular Ca2+). These various signals impact to a greater or lesser extent on multiple downstream effectors. Important concepts are that signal transmission often entails the targeted relocation of specific proteins in the cell, and the reversible formation of protein complexes by means of regulated protein phosphorylation. The signalling circuits may be completed by the phosphorylation of upstream effectors by downstream kinases, resulting in a modulation of the signal. Signalling is terminated and the components returned to the ground state largely by dephosphorylation. There is an indeterminant amount of cross-talk among the pathways, and many of the proteins in the pathways belong to families

  18. Cytokines and STATs in Liver Fibrosis.

    PubMed

    Kong, Xiaoni; Horiguchi, Norio; Mori, Masatomo; Gao, Bin

    2012-01-01

    Liver fibrosis, or cirrhosis, is a common end-stage condition of many chronic liver diseases after incomplete recovery from hepatocyte damage. During fibrosis progression, hepatocellular damage and inflammation trigger complex cellular events that result in collagen deposition and the disruption of the normal liver architecture. Hepatic stellate cell activation and transdifferentiation into myofibroblasts are key events in liver fibrogenesis. Research findings from cell culture and animal models have revealed that the Janus kinase-signal transducer and activator of transcription (Jak-STAT) signaling pathway, which can be activated by many cytokines, growth factors, and hormones, plays a critical role in hepatic fibrogenesis. This review summarizes the biological significance of diverse cytokines and their downstream signaling protein STATs in hepatic fibrogenesis.

  19. Graphene-based two-dimensional Janus materials

    NASA Astrophysics Data System (ADS)

    Ng, Sze-Wing; Noor, Nuruzzaman; Zheng, Zijian

    2018-04-01

    Two-dimensional (2D) Janus materials with opposing components and properties on two sides have recently attracted fevered attention from various research fields for use as, for example, oil/water separating membranes, interfacial layers for mass transfer, 2D sensors and actuators. The Janus structure allows for a unidirectional transportation system and programmed response to certain stimuli to be achieved. Graphene, the 2D honeycomb network formed from one atomic layer of carbon atoms, has also received substantial research interest because of its intriguing structure and fascinating properties. The high mechanical strength, flexibility and optical transparency make graphene a unique candidate as a building block of 2D Janus materials through asymmetric modification with different functional groups on the graphene surfaces. This article reviews graphene-based 2D Janus materials, starting with a theoretical understanding of the behavior of Janus graphene. Then, different strategies for fabricating Janus graphene and its derivatives are reviewed in detail according to the chemical strategies of the modification methods. The applications of graphene-based Janus materials are discussed with a specific focus on the Janus structures that lead to bandgap engineering, as well as the construction of a responsive system on graphene.

  20. Design and Synthesis of a Pan-Janus Kinase Inhibitor Clinical Candidate (PF-06263276) Suitable for Inhaled and Topical Delivery for the Treatment of Inflammatory Diseases of the Lungs and Skin

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jones, Peter; Storer, R. Ian; Sabnis, Yogesh A.

    By use of a structure-based computational method for identification of structurally novel Janus kinase (JAK) inhibitors predicted to bind beyond the ATP binding site, a potent series of indazoles was identified as selective pan-JAK inhibitors with a type 1.5 binding mode. Optimization of the series for potency and increased duration of action commensurate with inhaled or topical delivery resulted in potent pan-JAK inhibitor 2 (PF-06263276), which was advanced into clinical studies.

  1. Targeting RhoA/Rho kinase and p21-activated kinase signaling to prevent cancer development and progression.

    PubMed

    Chang, Yu-Wen E; Bean, Ronald R; Jakobi, Rolf

    2009-06-01

    Elevated RhoA/Rho kinase and p21-activated kinase signaling have been shown to promote cancer development and metastasis and have drawn much attention as potential targets of anti-cancer therapy. Elevated RhoA and Rho kinase activity promote cancer cell invasion and eventually lead to metastasis by disrupting E-cadherin-mediated adherens junctions and degradation of the extracellular matrix. Elevated p21-activated kinase activity promotes invasion by stimulating cell motility but also promotes cancer cell survival and growth. In this review we describe normal functions of RhoA/Rho kinase and p21-activated kinase signaling, mechanisms that lead to constitutive activation of RhoA/Rho kinase and p21-activated kinase pathways, and processes by which constitutive RhoA/Rho kinase and p21-activated kinase activity promote cancer development and progression to more aggressive and metastatic phenotypes. In addition, we summarize relevant patents on RhoA/Rho kinase and p21-activated kinase as targets of anti-cancer therapy and discuss the clinical potential of different approaches to modulate RhoA/Rho kinase and p21-activated kinase signaling.

  2. JAK2 inhibition sensitizes resistant EGFR-mutant lung adenocarcinoma to tyrosine kinase inhibitors

    PubMed Central

    Gao, Sizhi P.; Chang, Qing; Mao, Ninghui; Daly, Laura A.; Vogel, Robert; Chan, Tyler; Liu, Shu Hui; Bournazou, Eirini; Schori, Erez; Zhang, Haiying; Brewer, Monica Red; Pao, William; Morris, Luc; Ladanyi, Marc; Arcila, Maria; Manova-Todorova, Katia; de Stanchina, Elisa; Norton, Larry; Levine, Ross L.; Altan-Bonnet, Gregoire; Solit, David; Zinda, Michael; Huszar, Dennis; Lyden, David; Bromberg, Jacqueline F.

    2016-01-01

    Lung adenocarcinomas with mutant epidermal growth factor receptor (EGFR) respond to EGFR-targeted tyrosine kinase inhibitors (TKIs), but resistance invariably occurs. We found that the Janus kinase (JAK)/signal transduction and activator of transcription 3 (STAT3) signaling pathway was aberrantly increased in TKI-resistant EGFR-mutant non–small cell lung cancer (NSCLC) cells. JAK2 inhibition restored sensitivity to the EGFR inhibitor erlotinib in TKI-resistant cell lines and xenograft models of EGFR-mutant TKI-resistant lung cancer. JAK2 inhibition uncoupled EGFR from its negative regulator, suppressor of cytokine signaling 5 (SOCS5), consequently increasing EGFR abundance and restoring the tumor cells’ dependence on EGFR signaling. Furthermore, JAK2 inhibition led to heterodimerization of mutant and wild-type EGFR subunits, the activity of which was then blocked by TKIs. Our results reveal a mechanism whereby JAK2 inhibition overcomes acquired resistance to EGFR inhibitors and support the use of combination therapy with JAK and EGFR inhibitors for the treatment of EGFR-dependent NSCLC. PMID:27025877

  3. Adipocyte Fatty Acid Binding Protein Potentiates Toxic Lipids-Induced Endoplasmic Reticulum Stress in Macrophages via Inhibition of Janus Kinase 2-dependent Autophagy

    PubMed Central

    Hoo, Ruby L. C.; Shu, Lingling; Cheng, Kenneth K. Y.; Wu, Xiaoping; Liao, Boya; Wu, Donghai; Zhou, Zhiguang; Xu, Aimin

    2017-01-01

    Lipotoxicity is implicated in the pathogenesis of obesity-related inflammatory complications by promoting macrophage infiltration and activation. Endoplasmic reticulum (ER) stress and adipocyte fatty acid binding protein (A-FABP) play key roles in obesity and mediate inflammatory activity through similar signaling pathways. However, little is known about their interplay in lipid-induced inflammatory responses. Here, we showed that prolonged treatment of palmitic acid (PA) increased ER stress and expression of A-FABP, which was accompanied by reduced autophagic flux in macrophages. Over-expression of A-FABP impaired PA-induced autophagy associating with enhanced ER stress and pro-inflammatory cytokine production, while genetic ablation or pharmacological inhibition of A-FABP reversed the conditions. PA-induced expression of autophagy-related protein (Atg)7 was attenuated in A-FABP over-expressed macrophages, but was elevated in A-FABP-deficient macrophages. Mechanistically, A-FABP potentiated the effects of PA by inhibition of Janus Kinase (JAK)2 activity, thus diminished PA-induced Atg7 expression contributing to impaired autophagy and further augmentation of ER stress. These findings suggest that A-FABP acts as autophagy inhibitor to instigate toxic lipids-induced ER stress through inhibition of JAK2-dependent autophagy, which in turn triggers inflammatory responses in macrophages. A-FABP-JAK2 axis may represent an important pathological pathway contributing to obesity-related inflammatory diseases. PMID:28094778

  4. Repigmentation in vitiligo using the Janus kinase inhibitor tofacitinib may require concomitant light exposure.

    PubMed

    Liu, Lucy Y; Strassner, James P; Refat, Maggi A; Harris, John E; King, Brett A

    2017-10-01

    Vitiligo is an autoimmune disease in which cutaneous depigmentation occurs. Existing therapies are often inadequate. Prior reports have shown benefit of the Janus kinase (JAK) inhibitors. To evaluate the efficacy of the JAK 1/3 inhibitor tofacitinib in the treatment of vitiligo. This is a retrospective case series of 10 consecutive patients with vitiligo treated with tofacitinib. Severity of disease was assessed by body surface area of depigmentation. Ten consecutive patients were treated with tofacitinib. Five patients achieved some repigmentation at sites of either sunlight exposure or low-dose narrowband ultraviolet B phototherapy. Suction blister sampling revealed that the autoimmune response was inhibited during treatment in both responding and nonresponding lesions, suggesting that light rather than immunosuppression was primarily required for melanocyte regeneration. Limitations include the small size of the study population, retrospective nature of the study, and lack of a control group. Treatment of vitiligo with JAK inhibitors appears to require light exposure. In contrast to treatment with phototherapy alone, repigmentation during treatment with JAK inhibitors may require only low-level light. Maintenance of repigmentation may be achieved with JAK inhibitor monotherapy. These results support a model wherein JAK inhibitors suppress T cell mediators of vitiligo and light exposure is necessary for stimulation of melanocyte regeneration. Copyright © 2017 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  5. The kinase activity of the Ser/Thr kinase BUB1 promotes TGF-β signaling.

    PubMed

    Nyati, Shyam; Schinske-Sebolt, Katrina; Pitchiaya, Sethuramasundaram; Chekhovskiy, Katerina; Chator, Areeb; Chaudhry, Nauman; Dosch, Joseph; Van Dort, Marcian E; Varambally, Sooryanarayana; Kumar-Sinha, Chandan; Nyati, Mukesh Kumar; Ray, Dipankar; Walter, Nils G; Yu, Hongtao; Ross, Brian Dale; Rehemtulla, Alnawaz

    2015-01-06

    Transforming growth factor-β (TGF-β) signaling regulates cell proliferation and differentiation, which contributes to development and disease. Upon binding TGF-β, the type I receptor (TGFBRI) binds TGFBRII, leading to the activation of the transcription factors SMAD2 and SMAD3. Using an RNA interference screen of the human kinome and a live-cell reporter for TGFBR activity, we identified the kinase BUB1 (budding uninhibited by benzimidazoles-1) as a key mediator of TGF-β signaling. BUB1 interacted with TGFBRI in the presence of TGF-β and promoted the heterodimerization of TGFBRI and TGFBRII. Additionally, BUB1 interacted with TGFBRII, suggesting the formation of a ternary complex. Knocking down BUB1 prevented the recruitment of SMAD3 to the receptor complex, the phosphorylation of SMAD2 and SMAD3 and their interaction with SMAD4, SMAD-dependent transcription, and TGF-β-mediated changes in cellular phenotype including epithelial-mesenchymal transition (EMT), migration, and invasion. Knockdown of BUB1 also impaired noncanonical TGF-β signaling mediated by the kinases AKT and p38 MAPK (mitogen-activated protein kinase). The ability of BUB1 to promote TGF-β signaling depended on the kinase activity of BUB1. A small-molecule inhibitor of the kinase activity of BUB1 (2OH-BNPP1) and a kinase-deficient mutant of BUB1 suppressed TGF-β signaling and formation of the ternary complex in various normal and cancer cell lines. 2OH-BNPP1 administration to mice bearing lung carcinoma xenografts reduced the amount of phosphorylated SMAD2 in tumor tissue. These findings indicated that BUB1 functions as a kinase in the TGF-β pathway in a role beyond its established function in cell cycle regulation and chromosome cohesion. Copyright © 2015, American Association for the Advancement of Science.

  6. A Genetic Screen Reveals an Unexpected Role for Yorkie Signaling in JAK/STAT-Dependent Hematopoietic Malignancies in Drosophila melanogaster

    PubMed Central

    Anderson, Abigail M.; Bailetti, Alessandro A.; Rodkin, Elizabeth; De, Atish; Bach, Erika A.

    2017-01-01

    A gain-of-function mutation in the tyrosine kinase JAK2 (JAK2V617F) causes human myeloproliferative neoplasms (MPNs). These patients present with high numbers of myeloid lineage cells and have numerous complications. Since current MPN therapies are not curative, there is a need to find new regulators and targets of Janus kinase/Signal transducer and activator of transcription (JAK/STAT) signaling that may represent additional clinical interventions . Drosophila melanogaster offers a low complexity model to study MPNs as JAK/STAT signaling is simplified with only one JAK [Hopscotch (Hop)] and one STAT (Stat92E). hopTumorous-lethal (Tum-l) is a gain-of-function mutation that causes dramatic expansion of myeloid cells, which then form lethal melanotic tumors. Through an F1 deficiency (Df) screen, we identified 11 suppressors and 35 enhancers of melanotic tumors in hopTum-l animals. Dfs that uncover the Hippo (Hpo) pathway genes expanded (ex) and warts (wts) strongly enhanced the hopTum-l tumor burden, as did mutations in ex, wts, and other Hpo pathway genes. Target genes of the Hpo pathway effector Yorkie (Yki) were significantly upregulated in hopTum-l blood cells, indicating that Yki signaling was increased. Ectopic hematopoietic activation of Yki in otherwise wild-type animals increased hemocyte proliferation but did not induce melanotic tumors. However, hematopoietic depletion of Yki significantly reduced the hopTum-l tumor burden, demonstrating that Yki is required for melanotic tumors in this background. These results support a model in which elevated Yki signaling increases the number of hemocytes, which become melanotic tumors as a result of elevated JAK/STAT signaling. PMID:28620086

  7. Mediator kinase module and human tumorigenesis.

    PubMed

    Clark, Alison D; Oldenbroek, Marieke; Boyer, Thomas G

    2015-01-01

    Mediator is a conserved multi-subunit signal processor through which regulatory informatiosn conveyed by gene-specific transcription factors is transduced to RNA Polymerase II (Pol II). In humans, MED13, MED12, CDK8 and Cyclin C (CycC) comprise a four-subunit "kinase" module that exists in variable association with a 26-subunit Mediator core. Genetic and biochemical studies have established the Mediator kinase module as a major ingress of developmental and oncogenic signaling through Mediator, and much of its function in signal-dependent gene regulation derives from its resident CDK8 kinase activity. For example, CDK8-targeted substrate phosphorylation impacts transcription factor half-life, Pol II activity and chromatin chemistry and functional status. Recent structural and biochemical studies have revealed a precise network of physical and functional subunit interactions required for proper kinase module activity. Accordingly, pathologic change in this activity through altered expression or mutation of constituent kinase module subunits can have profound consequences for altered signaling and tumor formation. Herein, we review the structural organization, biological function and oncogenic potential of the Mediator kinase module. We focus principally on tumor-associated alterations in kinase module subunits for which mechanistic relationships as opposed to strictly correlative associations are established. These considerations point to an emerging picture of the Mediator kinase module as an oncogenic unit, one in which pathogenic activation/deactivation through component change drives tumor formation through perturbation of signal-dependent gene regulation. It follows that therapeutic strategies to combat CDK8-driven tumors will involve targeted modulation of CDK8 activity or pharmacologic manipulation of dysregulated CDK8-dependent signaling pathways.

  8. Ghrelin augments murine T-cell proliferation by activation of the phosphatidylinositol-3-kinase, extracellular signal-regulated kinase and protein kinase C signaling pathways

    PubMed Central

    Lee, Jun Ho; Patel, Kalpesh; Tae, Hyun Jin; Lustig, Ana; Kim, Jie Wan; Mattson, Mark P.; Taub, Dennis D.

    2014-01-01

    Thymic atrophy occurs during normal aging, and is accelerated by exposure to chronic stressors that elevate glucocorticoid levelsand impair the naïve T cell output. The orexigenic hormone ghrelin was recently shown to attenuate age-associated thymic atrophy. Here, we report that ghrelin enhances the proliferation of murine CD4+ primary T cells and a CD4+ T-cell line. Ghrelin induced activation of the ERK1/2 and Akt signaling pathways, via upstream activation of phosphatidylinositol-3-kinase and protein kinase C, to enhance T-cell proliferation. Moreover, ghrelin induced expression of the cell cycle proteins cyclin D1, cyclin E, cyclin-dependent kinase 2 (CDK2) and retinoblastoma phosphorylation. Finally, ghrelin activated the above-mentioned signaling pathways and stimulated thymocyte proliferation in young and older mice in vivo. PMID:25447526

  9. PSM/SH2-B distributes selected mitogenic receptor signals to distinct components in the PI3-kinase and MAP kinase signaling pathways.

    PubMed

    Deng, Youping; Xu, Hu; Riedel, Heimo

    2007-02-15

    The Pro-rich, PH, and SH2 domain containing mitogenic signaling adapter PSM/SH2-B has been implicated as a cellular partner of various mitogenic receptor tyrosine kinases and related signaling mechanisms. Here, we report in a direct comparison of three peptide hormones, that PSM participates in the assembly of distinct mitogenic signaling complexes in response to insulin or IGF-I when compared to PDGF in cultured normal fibroblasts. The complex formed in response to insulin or IGF-I involves the respective peptide hormone receptor and presumably the established components leading to MAP kinase activation. However, our data suggest an alternative link from the PDGF receptor via PSM directly to MEK1/2 and consequently also to p44/42 activation, possibly through a scaffold protein. At least two PSM domains participate, the SH2 domain anticipated to link PSM to the respective receptor and the Pro-rich region in an association with an unidentified downstream component resulting in direct MEK1/2 and p44/42 regulation. The PDGF receptor signaling complex formed in response to PDGF involves PI 3-kinase in addition to the same components and interactions as described for insulin or IGF-I. PSM associates with PI 3-kinase via p85 and in addition the PSM PH domain participates in the regulation of PI 3-kinase activity, presumably through membrane interaction. In contrast, the PSM Pro-rich region appears to participate only in the MAP kinase signal. Both pathways contribute to the mitogenic response as shown by cell proliferation, survival, and focus formation. PSM regulates p38 MAP kinase activity in a pathway unrelated to the mitogenic response.

  10. Sensor kinase KinB and its pathway-associated key factors sense the signal of nutrition starvation in sporulation of Bacillus subtilis.

    PubMed

    Liu, Weipeng; He, Zeying; Gao, Feng; Yan, Jinyuan; Huang, Xiaowei

    2018-01-03

    Bacillus subtilis responds to environmental stress cues and develops endospores for survival. In the process of endospore formation, sporulation initiation is a vital stage and this stage is governed by autophosphorylation of the sensor histidine kinases. The second major sensor kinase KinB perceives the intracellular changes of GTP and ATP during sporulation. However, determination of the environmental signals as well as its related signaling pathway of KinB requires further elucidation. Our current study found that, contrary to the sporulation failure induced by ΔkinA in the nutrient-rich 2× SG medium, the sensor kinase KinB sensed the environmental cues in the nutrient-poor MM medium. Two other membrane proteins, KapB and KbaA, also responded similarly to the same external signal as KinB. Both KapB and KbaA acted upstream of KinB, but they exerted their regulation upon KinB independently. Furthermore, we demonstrated that both the SH3 domain and the α-helix structure in KapB are required for sensing or transducing the signal of sporulation initiation. Collectively, our work here supplied the direct evidences that KinB and its pathway sense the external signal of nutrient starvation in MM medium, and further analyzes the interrelationship among KinB, KbaA, and KapB. © 2018 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  11. Pyrimidine tract-binding protein 1 mediates pyruvate kinase M2-dependent phosphorylation of signal transducer and activator of transcription 3 and oncogenesis in anaplastic large cell lymphoma.

    PubMed

    Hwang, Steven R; Murga-Zamalloa, Carlos; Brown, Noah; Basappa, Johnvesly; McDonnell, Scott Rp; Mendoza-Reinoso, Veronica; Basrur, Venkatesha; Wilcox, Ryan; Elenitoba-Johnson, Kojo; Lim, Megan S

    2017-08-01

    PKM2 (pyruvate kinase M2), a critical regulator of glycolysis, is phosphorylated by numerous growth factor receptors and oncogenic tyrosine kinases including NPM-ALK which is expressed in a subset of aggressive T-cell non-Hodgkin lymphomas known as anaplastic large cell lymphoma, ALK-positive. Our previous work demonstrated that phosphorylation of Y105-PKM2 by NPM-ALK regulates a major metabolic shift to promote lymphomagenesis. In addition to its role in metabolism, recent studies have shown that PKM2 promotes oncogenesis by phosphorylating nuclear STAT3 (signal transducer and activator of transcription 3) and regulating transcription of genes involved in cell survival and proliferation. We hypothesized that identification of novel PKM2 interactors could provide additional insights into its expanding functional role in cancer. To this end, immunocomplexes of FLAG-tagged PKM2 were isolated from NPM-ALK-positive ALCL (anaplastic large cell lymphoma) cells and subjected to liquid chromatography tandem mass spectrometry (LC-MS/MS) which led to the identification of polypyrimidine tract-binding protein (PTBP1) as a novel interactor of PKM2. The interaction between PTBP1 and PKM2 was restricted to the nucleus and was dependent on NPM-ALK mediated Y105 phosphorylation of PKM2. Stable shRNA-mediated silencing of PTBP1 resulted in a marked decrease in pY105-PKM2 and pY705-STAT3 which led to decreased ALCL cell proliferation and colony formation. Overall, our data demonstrate that PTBP1 interacts with PKM2 and promotes ALCL oncogenesis by facilitating PKM2-dependent activation of STAT3 within the nucleus.

  12. Significance of expression of suppressor of cytokine signaling proteins: Suppressor of cytokine signaling-1, suppressor of cytokine signaling-2, and suppressor of cytokine signaling-3 in papillary thyroid cancer.

    PubMed

    Kobawala, Toral Pundrik; Trivedi, Trupti I; Gajjar, Kinjal Kevin; Patel, Girish H; Ghosh, Nandita R

    2017-01-01

    Uncontrolled cytokine signal transduction largely associated with oncogene activation, can have disastrous biological consequences. The suppressor of cytokine signaling (SOCS) proteins represent one of the mechanisms by which this rampant signaling can be dissipated. Thus, we aimed to study the expression of SOCS-1, SOCS-2, and SOCS-3 in patients having benign thyroid disease and papillary thyroid cancer. SOCS protein expression was studied in 45 patients with benign thyroid disease and in 83 papillary thyroid cancer patients by immunohistochemistry and their association with clinicopathological characteristics and overall survival in cancer patients were analyzed using SPSS software. Expressions of SOCS proteins were significantly higher in papillary thyroid cancer than in patients having benign disease. SOCS-1 expression was predominantly higher in males (P = 0.004), unilateral tumors (P = 0.030), and noninflammatory conditions (P = 0.028). SOCS-1 expression was also able to predict poor overall survival in subgroup of papillary thyroid cancer patients having larger tumor size (P = 0.013) and advanced stage disease (P = 0.033). Expression of SOCS-2 significantly correlated with tumor size (P = 0.017), extrathyroidal extension (P = 0.000), residual disease (P = 0.043), and treatment (P = 0.007), while preponderance of SOCS-3 expression was observed in males (P = 0.030) and in patients having extrathyroidal extension (P = 0.011) and absence of metastasis (P = 0.032). Expression of the studied SOCS proteins may be a consequence of activation of Janus kinase-signal transducers and activators of transcription and other pathways supporting growth and survival of cancer cells that are sustained by several cytokines. Thus, SOCS-1, SOCS-2, and SOCS-3 proteins may directly or indirectly, have important roles in development and pathogenesis of papillary thyroid cancer.

  13. MRG1, the product of a melanocyte-specific gene related gene, is a cytokine-inducible transcription factor with transformation activity

    PubMed Central

    Sun, Hui Bin; Zhu, Yuan Xiao; Yin, Tinggui; Sledge, George; Yang, Yu-Chung

    1998-01-01

    Identification of cytokine-inducible genes is imperative for determining the mechanisms of cytokine action. A cytokine-inducible gene, mrg1 [melanocyte-specific gene (msg1) related gene], was identified through mRNA differential display of interleukin (IL) 9-stimulated and unstimulated mouse helper T cells. In addition to IL-9, mrg1 can be induced by other cytokines and biological stimuli, including IL-1α, -2, -4, -6, and -11, granulocyte/macrophage colony-stimulating factor, interferon γ, platelet-derived growth factor, insulin, serum, and lipopolysaccharide in diverse cell types. The induction of mrg1 by these stimuli appears to be transient, with induction kinetics similar to other primary response genes, implicating its role in diverse biological processes. Deletion or point mutations of either the Box1 motif (binds Janus kinase 1) or the signal transducer and activator of transcription 3 binding site-containing region within the intracellular domain of the IL-9 receptor ligand binding subunit abolished or greatly reduced mrg1 induction by IL-9, suggesting that the Janus kinase/signal transducer and activator of transcription signaling pathway is required for mrg1 induction, at least in response to IL-9. Transfection of mrg1 cDNA into TS1, an IL-9-dependent mouse T cell line, converted these cells to IL-9-independent growth through a nonautocrine mechanism. Overexpression of mrg1 in Rat1 cells resulted in loss of cell contact inhibition, anchorage-independent growth in soft agar, and tumor formation in nude mice, demonstrating that mrg1 is a transforming gene. MRG1 is a transcriptional activator and may represent a founding member of an additional family of transcription factors. PMID:9811838

  14. Acoustic transducer for nuclear reactor monitoring

    DOEpatents

    Ahlgren, Frederic F.; Scott, Paul F.

    1977-01-01

    A transducer to monitor a parameter and produce an acoustic signal from which the monitored parameter can be recovered. The transducer comprises a modified Galton whistle which emits a narrow band acoustic signal having a frequency dependent upon the parameter being monitored, such as the temperature of the cooling media of a nuclear reactor. Multiple locations within a reactor are monitored simultaneously by a remote acoustic receiver by providing a plurality of transducers each designed so that the acoustic signal it emits has a frequency distinct from the frequencies of signals emitted by the other transducers, whereby each signal can be unambiguously related to a particular transducer.

  15. Janus kinase 2 inhibitors in myeloproliferative disorders.

    PubMed

    Lucia, Eugenio; Recchia, Anna Grazia; Gentile, Massimo; Bossio, Sabrina; Vigna, Ernesto; Mazzone, Carla; Madeo, Antonio; Morabito, Lucio; Gigliotti, Vincenzo; De Stefano, Laura; Caruso, Nadia; Servillo, Pasquale; Franzese, Stefania; Bisconte, Maria Grazia; Gentile, Carlo; Morabito, Fortunato

    2011-01-01

    JAK2 is an obligatory kinase for the proliferation and differentiation of erythroid cells and megakaryocytes thus representing a relevant therapeutic target for agents that specifically inhibit its activity particularly in myeloproliferative disorders (MPD) harboring JAK2(V617F) mutations. We discuss the physiopathology of the JAK2 signaling pathway and review clinical trials of JAK2 inhibitors for the treatment of MPD using papers and meeting abstracts published up to September 2010. This review helps in understanding the potential role of JAK2 inhibitors in MPD clinical trials and provides a comprehensive review regarding their efficacy and safety in these disorders. JAK2 inhibitors may prove to be useful only for suppressing disease manifestations. However, unlike drugs such as IFN which are capable of eliminating the malignant clone, JAK2 inhibitors are unable to eradicate the disease. In fact, results to date indicate that although these inhibitors reduce splenomegaly and alleviate constitutional symptoms irrespective of JAK2 mutational status, most have only a modest impact on the JAK2(V617F) allele burden. Considering the relevant risk of serious complications in patients undergoing splenectomy, these drugs could find a suitable indication in patients with myelofibrosis awaiting bone marrow transplantation.

  16. Mediator kinase module and human tumorigenesis

    PubMed Central

    Clark, Alison D.; Oldenbroek, Marieke; Boyer, Thomas G.

    2016-01-01

    Mediator is a conserved multi-subunit signal processor through which regulatory informatiosn conveyed by gene-specific transcription factors is transduced to RNA Polymerase II (Pol II). In humans, MED13, MED12, CDK8 and Cyclin C (CycC) comprise a four-subunit “kinase” module that exists in variable association with a 26-subunit Mediator core. Genetic and biochemical studies have established the Mediator kinase module as a major ingress of developmental and oncogenic signaling through Mediator, and much of its function in signal-dependent gene regulation derives from its resident CDK8 kinase activity. For example, CDK8-targeted substrate phosphorylation impacts transcription factor half-life, Pol II activity and chromatin chemistry and functional status. Recent structural and biochemical studies have revealed a precise network of physical and functional subunit interactions required for proper kinase module activity. Accordingly, pathologic change in this activity through altered expression or mutation of constituent kinase module subunits can have profound consequences for altered signaling and tumor formation. Herein, we review the structural organization, biological function and oncogenic potential of the Mediator kinase module. We focus principally on tumor-associated alterations in kinase module subunits for which mechanistic relationships as opposed to strictly correlative associations are established. These considerations point to an emerging picture of the Mediator kinase module as an oncogenic unit, one in which pathogenic activation/deactivation through component change drives tumor formation through perturbation of signal-dependent gene regulation. It follows that therapeutic strategies to combat CDK8-driven tumors will involve targeted modulation of CDK8 activity or pharmacologic manipulation of dysregulated CDK8-dependent signaling pathways. PMID:26182352

  17. JAK/STAT signaling pathway-mediated immune response in silkworm (Bombyx mori) challenged by Beauveria bassiana.

    PubMed

    Geng, Tao; Lv, Ding-Ding; Huang, Yu-Xia; Hou, Cheng-Xiang; Qin, Guang-Xing; Guo, Xi-Jie

    2016-12-20

    Innate immunity was critical in insects defensive system and able to be induced by Janus kinase/signal transducer and activator of transcription cascade transduction (JAK/STAT) signaling pathway. Currently, it had been identified many JAK/STAT signaling pathway-related genes in silkworm, but little function was known on insect innate immunity. To explore the roles of JAK/STAT pathway in antifungal immune response in silkworm (Bombyx mori) against Beauveria bassiana infection, the expression patterns of B. mori C-type lectin 5 (BmCTL5) and genes encoding 6 components of JAK/STAT signaling pathway in silkworm challenged by B. bassiana were analyzed using quantitative real time PCR. Meanwhile the activation of JAK/STAT signaling pathway by various pathogenic micro-organisms and the affect of JAK/STAT signaling pathway inhibitors on antifungal activity in silkworm hemolymph was also detected. Moreover, RNAi assay of BmCTL5 and the affect on expression levels of signaling factors were also analyzed. We found that JAK/STAT pathway could be obviously activated in silkworm challenged with B. bassiana and had no response to bacteria and B. mori cytoplasmic polyhedrosis virus (BmCPV). However, the temporal expression patterns of JAK/STAT signaling pathway related genes were significantly different. B. mori downstream receptor kinase (BmDRK) might be a positive regulator of JAK/STAT signaling pathway in silkworm against B. bassiana infection. Moreover, antifungal activity assay showed that the suppression of JAK/STAT signaling pathway by inhibitors could significantly inhibit the antifungal activity in hemolymph and resulted in increased sensitivity of silkworm to B. bassiana infection, indicating that JAK/STAT signaling pathway might be involved in the synthesis and secretion of antifungal substances. The results of RNAi assays suggested that BmCTL5 might be one pattern recognition receptors for JAK/STAT signaling pathway in silkworm. These findings yield insights for better

  18. Nuclear Localization of Suppressor of Cytokine Signaling-1 Regulates Local Immunity in the Lung

    PubMed Central

    Zimmer, Jana; Weitnauer, Michael; Boutin, Sébastien; Küblbeck, Günter; Thiele, Sabrina; Walker, Patrick; Lasitschka, Felix; Lunding, Lars; Orinska, Zane; Vock, Christina; Arnold, Bernd; Wegmann, Michael; Dalpke, Alexander

    2016-01-01

    Suppressor of cytokine signaling 1 (SOCS1) is a negative feedback inhibitor of cytoplasmic Janus kinase and signal transducer and activator of transcription (STAT) signaling. SOCS1 also contains a nuclear localization sequence (NLS), yet, the in vivo importance of nuclear translocation is unknown. We generated transgenic mice containing mutated Socs1ΔNLS that fails to translocate in the cell nucleus (MGLtg mice). Whereas mice fully deficient for SOCS1 die within the first 3 weeks due to excessive interferon signaling and multiorgan inflammation, mice expressing only non-nuclear Socs1ΔNLS (Socs1−/−MGLtg mice) were rescued from early lethality. Canonical interferon gamma signaling was still functional in Socs1−/−MGLtg mice as shown by unaltered tyrosine phosphorylation of STAT1 and whole genome expression analysis. However, a subset of NFκB inducible genes was dysregulated. Socs1−/−MGLtg mice spontaneously developed low-grade inflammation in the lung and had elevated Th2-type cytokines. Upon ovalbumin sensitization and challenge, airway eosinophilia was increased in Socs1−/−MGLtg mice. Decreased transepithelial electrical resistance in trachea epithelial cells from Socs1−/−MGLtg mice suggests disrupted epithelial cell barrier. The results indicate that nuclear SOCS1 is a regulator of local immunity in the lung and unravel a so far unrecognized function for SOCS1 in the cell nucleus. PMID:27917175

  19. Chlorogenic acid induces apoptosis to inhibit inflammatory proliferation of IL-6-induced fibroblast-like synoviocytes through modulating the activation of JAK/STAT and NF-κB signaling pathways

    PubMed Central

    LOU, LIXIA; ZHOU, JINGWEI; LIU, YUJUN; WEI, YI; ZHAO, JIULI; DENG, JIAGANG; DONG, BIN; ZHU, LINGQUN; WU, AIMING; YANG, YINGXI; CHAI, LIMIN

    2016-01-01

    Chlorogenic acid (CGA) is the primary constituent of Caulis Lonicerae, a Chinese herb used for the treatment of rheumatoid arthritis (RA). The present study aimed to investigate whether CGA was able to inhibit the proliferation of the fibroblast-like synoviocyte cell line (RSC-364), stimulated by interleukin (IL)-6, through inducing apoptosis. Following incubation with IL-6 or IL-6 and CGA, the cellular proliferation of RSC-364 cells was detected by MTT assay. The ratio of apoptosed cells were detected by flow cytometry. Western blot analysis was performed to observe protein expression levels of key molecules involved in the Janus-activated kinase/signal transducer and activator of transcription 3 (JAK/STAT) signaling pathway [phosphorylated (p)-STAT3, JAK1 and gp130] and the nuclear factor κB (NF-κB) signaling pathway [phosphorylated (p)-inhibitor of κB kinase subunit α/β and NF-κB p50). It was revealed that CGA was able to inhibit the inflammatory proliferation of RSC-364 cells mediated by IL-6 through inducing apoptosis. CGA was also able to suppress the expression levels of key molecules in the JAK/STAT and NF-κB signaling pathways, and inhibit the activation of these signaling pathways in the inflammatory response through IL-6-mediated signaling, thereby resulting in the inhibition of the inflammatory proliferation of synoviocytes. The present results indicated that CGA may have potential as a novel therapeutic agent for inhibiting inflammatory hyperplasia of the synovium through inducing synoviocyte apoptosis in patients with RA. PMID:27168850

  20. Non-Smad signaling pathways.

    PubMed

    Mu, Yabing; Gudey, Shyam Kumar; Landström, Maréne

    2012-01-01

    Transforming growth factor-beta (TGFβ) is a key regulator of cell fate during embryogenesis and has also emerged as a potent driver of the epithelial-mesenchymal transition during tumor progression. TGFβ signals are transduced by transmembrane type I and type II serine/threonine kinase receptors (TβRI and TβRII, respectively). The activated TβR complex phosphorylates Smad2 and Smad3, converting them into transcriptional regulators that complex with Smad4. TGFβ also uses non-Smad signaling pathways such as the p38 and Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) pathways to convey its signals. Ubiquitin ligase tumor necrosis factor (TNF)-receptor-associated factor 6 (TRAF6) and TGFβ-associated kinase 1 (TAK1) have recently been shown to be crucial for the activation of the p38 and JNK MAPK pathways. Other TGFβ-induced non-Smad signaling pathways include the phosphoinositide 3-kinase-Akt-mTOR pathway, the small GTPases Rho, Rac, and Cdc42, and the Ras-Erk-MAPK pathway. Signals induced by TGFβ are tightly regulated and specified by post-translational modifications of the signaling components, since they dictate the subcellular localization, activity, and duration of the signal. In this review, we discuss recent findings in the field of TGFβ-induced responses by non-Smad signaling pathways.

  1. Spatio-temporal kinetics of growth hormone receptor signaling in single cells using FRET microscopy.

    PubMed

    Biener-Ramanujan, Eva; Ramanujan, V Krishnan; Herman, Brian; Gertler, Arieh

    2006-08-01

    The growth hormone (GH) receptor (R)-mediated JAK2 (Janus kinase-2)-STAT5 (signaling transducer and activator of transcription-5) pathway involves a cascade of protein-protein interactions and tyrosine phosphorylations that occur in a spatially and temporally sensitive manner in cells. To study GHR dimerization or GH-induced conformational change of predimerized GHRs and STAT5 activation kinetics in intact cells, fluorescence resonance energy transfer (FRET) and live-cell imaging methods were employed. FRET measurements at the membrane of HEK-293T cells co-expressing GHRs tagged at the C-terminus with cyan (C) and yellow (Y) fluorescent proteins (FPs) revealed transient GHR dimerization lasting 2-3 min, with a maximum at 3 min after GH stimulation, which was sufficient to induce STAT5 activation. The transient nature of the dimerization or GH-induced conformational change of predimerized GHRs kinetics was not a result of GHR internalization, as neither potassium- nor cholesterol-depletion treatments prolonged the FRET signal. YFP-tagged STAT5 recruitment to the membrane, binding to GHR-CFP, and phosphorylation, occurred within minutes of GH stimulation. Activated STAT5a-YFP did not show nuclear accumulation, despite nuclear pSTAT5 increase, suggesting high turnover of STAT5 nuclear shuttling. Although GHR dimerization and STAT5 activation have been reported previously, this is the first spatially resolved demonstration of GHR-signaling kinetics in intact cells.

  2. Amphiphilic Soft Janus Particles as Interfacial Stabilizers

    NASA Astrophysics Data System (ADS)

    Wang, Wenda; Niu, Sunny; Sosa, Chris; Prud'Homme, Robert; Priestley, Rodney; Priestley Polymer Group Team; Prud'homme Research Group Team

    Janus particles, which incorporate two or more ``faces'' with different chemical functionality, have attracted great attention in scientific research. Amphiphilic Janus particles have two faces with distinctly different hydrophobicity. This can be thought of as colloidal surfactants. Theoretical studies on the stabilization of emulsions using Janus particles have confirmed higher efficiency. Herein we synthesize the narrow distributed amphiphilic polymeric Janus particles via Precipitation-Induced Self-Assembly (PISA). The efficiency of the amphiphilic Janus particles are tested on different oil/water systems. Biocompatible polymers can also be used on this strategy and may potentially have wide application for food emulsion, cosmetics and personal products.

  3. Cytokines and STATs in Liver Fibrosis

    PubMed Central

    Kong, Xiaoni; Horiguchi, Norio; Mori, Masatomo; Gao, Bin

    2012-01-01

    Liver fibrosis, or cirrhosis, is a common end-stage condition of many chronic liver diseases after incomplete recovery from hepatocyte damage. During fibrosis progression, hepatocellular damage and inflammation trigger complex cellular events that result in collagen deposition and the disruption of the normal liver architecture. Hepatic stellate cell activation and transdifferentiation into myofibroblasts are key events in liver fibrogenesis. Research findings from cell culture and animal models have revealed that the Janus kinase-signal transducer and activator of transcription (Jak-STAT) signaling pathway, which can be activated by many cytokines, growth factors, and hormones, plays a critical role in hepatic fibrogenesis. This review summarizes the biological significance of diverse cytokines and their downstream signaling protein STATs in hepatic fibrogenesis. PMID:22493582

  4. Tangeretin inhibits extracellular-signal-regulated kinase (ERK) phosphorylation.

    PubMed

    Van Slambrouck, Séverine; Parmar, Virinder S; Sharma, Sunil K; De Bondt, Bart; Foré, Fleur; Coopman, Peter; Vanhoecke, Barbara W; Boterberg, Tom; Depypere, Herman T; Leclercq, Guy; Bracke, Marc E

    2005-03-14

    Tangeretin is a methoxyflavone from citrus fruits, which inhibits growth of human mammary cancer cells and cytolysis by natural killer cells. Attempting to unravel the flavonoid's action mechanism, we found that it inhibited extracellular-signal-regulated kinases 1/2 (ERK1/2) phosphorylation in a dose- and time-dependent way. In human T47D mammary cancer cells this inhibition was optimally observed after priming with estradiol. The spectrum of the intracellular signalling kinase inhibition was narrow and comparison of structural congeners showed that inhibition of ERK phosphorylation was not unique for tangeretin. Our data add tangeretin to the list of small kinase inhibitors with a restricted intracellular inhibition profile.

  5. Akt-RSK-S6-kinase Signaling Networks Activated by Oncogenic Receptor Tyrosine Kinases

    PubMed Central

    Moritz, Albrecht; Li, Yu; Guo, Ailan; Villén, Judit; Wang, Yi; MacNeill, Joan; Kornhauser, Jon; Sprott, Kam; Zhou, Jing; Possemato, Anthony; Ren, Jian Min; Hornbeck, Peter; Cantley, Lewis C.; Gygi, Steven P.; Rush, John; Comb, Michael J.

    2011-01-01

    Receptor tyrosine kinases (RTKs) activate pathways mediated by serine/threonine (Ser/Thr) kinases such as the PI3K (phosphatidylinositol 3-kinase)-Akt pathway, the Ras-MAPK (mitogen-activated protein kinase)-RSK pathway, and the mTOR (mammalian target of rapamycin)-p70 S6 pathway that control important aspects of cell growth, proliferation, and survival. The Akt, RSK, and p70 S6 family of protein kinases transmit signals by phosphorylating substrates on a RxRxxS/T motif. Here, we developed a large-scale proteomic approach to identify over 200 substrates of this kinase family in cancer cell lines driven by the c-Met, epidermal growth factor receptor (EGFR), or platelet-derived growth factor receptor a (PDGFRα) RTKs. We identified a subset of proteins with RxRxxS/T sites for which phosphorylation was decreased by RTKIs as well as by inhibitors of the PI3K, mTOR, and MAPK pathways and determined the effects of siRNA directed against these substrates on cell viability. We found that phosphorylation of the protein chaperone SGTA (small glutamine-rich tetratricopeptide repeat-containing protein alpha) at Ser305 is essential for PDGFRα stabilization and cell survival in PDGFRα-dependent cancer cells. Our approach provides a new view of RTK and Akt-RSK-S6 kinase signaling, revealing many previously unidentified Akt-RSK-S6 kinase substrates that merit further consideration as targets for combination therapy with RTKIs. PMID:20736484

  6. Emerging roles for IL-11 signaling in cancer development and progression: Focus on breast cancer.

    PubMed

    Johnstone, Cameron N; Chand, Ashwini; Putoczki, Tracy L; Ernst, Matthias

    2015-10-01

    Interleukin (IL)-11 is a member of the IL-6 family of cytokines that is defined by the shared use of the GP130 signal transducing receptor subunit. In addition of its long recognized activities as a hemopoietic growth factor, IL-11 has an emerging role in epithelial cancer biology. Through the activation of the GP130-Janus kinase signaling cascade and associated transcription factor STAT3, IL-11 can confer many of the tumor intrinsic 'hallmark' capabilities to neoplastic cells, if they express the ligand-specific IL-11Rα receptor subunit. Accordingly, IL-11 signaling has recently been identified as a rate-limiting step for the growth tumors arising from the mucosa of the gastrointestinal tract. However, there is less appreciation for a potential role of IL-11 to support breast cancer progression, apart from its well documented capacity to facilitate bone metastasis. Here we review evidence that IL-11 expression in breast cancer correlates with poor disease outcome and discuss some of the molecular mechanisms that are likely to underpin these observations. These include the capacity of IL-11 to stimulate survival and proliferation of cancer cells alongside angiogenesis of the primary tumor and of metastatic progenies at distant organs. We review current strategies to interfere with IL-11 signaling and advocate that inhibition of IL-11 signaling may represent an emerging therapeutic opportunity for numerous cancers. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. How half-coated janus particles enter cells.

    PubMed

    Gao, Yuan; Yu, Yan

    2013-12-26

    Janus particles possess functional asymmetry and directionality within a single entity and thus are predicted to enable many promising biomedical applications that are not offered by homogeneous particles. However, it remains elusive what role the Janus principle plays in Janus particle-cell interactions, particularly in cellular uptake. We studied how asymmetric distribution of ligands on half-coated Janus microparticles dictates the membrane dynamics during receptor-mediated particle uptake, and found key differences from those characteristic of homogeneous particles. Live-cell fluorescence imaging combined with single-particle level quantification of particle-cell membrane interactions shows that the asymmetric distribution of ligands leads to a three-step endocytic process: membrane cup formation on the ligand-coated hemisphere, stalling at the Janus interface, and rapid membrane protrusion on the ligand-absent hemisphere to complete the particle engulfment. The direct correlation between the spatial presentation of ligands on Janus particles and the temporal changes of membrane dynamics revealed in this work elucidates the potential of using the Janus principle to fine-tune particle-cell interactions.

  8. Signal transduction in neurons: effects of cellular prion protein on fyn kinase and ERK1/2 kinase.

    PubMed

    Tomasi, Vittorio

    2010-12-16

    It has been reported that cellular prion protein (PrPc) co-localizes with caveolin-1 and participates to signal transduction events by recruiting Fyn kinase. As PrPc is a secreted protein anchored to the outer surface membrane through a glycosylphosphatidylinositol (GPI) anchor (secPrP) and caveolin-1 is located in the inner leaflet of plasma membrane, there is a problem of how the two proteins can physically interact each other and transduce signals. By using the GST-fusion proteins system we observed that PrPc strongly interacts with caveolin-1 scaffolding domain and with a caveolin-1 hydrophilic C-terminal region, but not with the caveolin-1 N-terminal region. In vitro binding experiments were also performed to define the site(s) of PrPc interacting with cav-1. The results are consistent with a participation of PrPc octapeptide repeats motif in the binding to caveolin-1 scaffolding domain. The caveolar localization of PrPc was ascertained by co-immunoprecipitation, by co-localization after flotation in density gradients and by confocal microscopy analysis of PrPc and caveolin-1 distributions in a neuronal cell line (GN11) expressing caveolin-1 at high levels. We observed that, after antibody-mediated cross-linking or copper treatment, PrPc was internalized probably into caveolae. We propose that following translocation from rafts to caveolae or caveolae-like domains, secPrP could interact with caveolin-1 and induce signal transduction events.

  9. Piezoelectric transducer

    NASA Technical Reports Server (NTRS)

    Conragan, J.; Muller, R. S.

    1970-01-01

    Transducer consists of a hybrid thin film and a piezoelectric transistor that acts as a stress-sensitive device with built-in gain. It provides a stress/strain transducer that incorporates a signal amplification stage and sensor in a single package.

  10. Dendritic cells with increased expression of suppressor of cytokine signaling 1(SOCS1) gene ameliorate lipopolysaccharide/d-galactosamine-induced acute liver failure.

    PubMed

    Li, Shan-Shan; Yang, Min; Chen, Yong-Ping; Tang, Xin-Yue; Zhang, Sheng-Guo; Ni, Shun-Lan; Yang, Nai-Bin; Lu, Ming-Qin

    2018-05-28

    Acute liver failure is a devastating clinical syndrome with extremely terrible inflammation reaction, which is still lack of effective treatment in clinic. Suppressor of Cytokine Signaling 1 protein is inducible intracellular negative regulator of Janus kinases (JAK)/signal transducers and activators of transcription (STAT) pathway that plays essential role in inhibiting excessive intracellular signaling cascade and preventing autoimmune reaction. In this paper, we want to explore whether dendritic cells (DCs) with overexpression of SOCS1 have a therapeutic effect on experimental acute liver failure. Bone marrow derived dendritic cells were transfected with lentivirus encoding SOCS1 and negative control lentivirus, thereafter collected for costimulatory molecules analysis, allogeneic Mixed Lymphocyte Reaction and Western blot test of JAK/STAT pathway. C57BL/6 mice were randomly separated into normal control and treatment groups which respectively received tail vein injection of modified DCs, negative control DCs and normal saline 12 h earlier than acute liver failure induction. Our results indicated that DCs with overexpression of SOCS1 exhibited like regulatory DCs (DCregs) with low level of costimulatory molecules and poor allostimulatory ability in vitro, which was supposed to correlate with block of JAK2/STAT1 signaling. In vivo tests, we found that infusion of modified DCs increased survival rate of acute liver failure mice and alleviate liver injury via inhibition of TLR4/HMGB1 pathway. We concluded that DCs transduced with SOCS1 gene exhibit as DCregs through negative regulation of JAK2/STAT1 pathway and ameliorated lipopolysaccharide/d-galactosamine induced acute liver failure via inhibition of TLR4 pathway. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Hypoxic Tumor Kinase Signaling Mediated by STAT5A in Development of Castration-Resistant Prostate Cancer

    PubMed Central

    Røe, Kathrine; Bratland, Åse; Vlatkovic, Ljiljana; Ragnum, Harald Bull; Saelen, Marie Grøn; Olsen, Dag Rune; Marignol, Laure; Ree, Anne Hansen

    2013-01-01

    In this study, we hypothesized that androgen-deprivation therapy (ADT) in prostate cancer, although initially efficient, induces changes in the tumor kinome, which subsequently promote development of castration-resistant (CR) disease. Recognizing the correlation between tumor hypoxia and poor prognosis in prostate cancer, we further hypothesized that such changes might be influenced by hypoxia. Microarrays with 144 kinase peptide substrates were applied to analyze CWR22 prostate carcinoma xenograft samples from ADT-naïve, androgen-deprived (AD), long-term AD (ADL), and CR disease stages. The impact of hypoxia was assessed by matching the xenograft kinase activity profiles with those acquired from hypoxic and normoxic prostate carcinoma cell cultures, whereas the clinical relevance was evaluated by analyzing prostatectomy tumor samples from patients with locally advanced disease, either in ADT-naïve or early CR disease stages. By using this novel peptide substrate microarray method we revealed high kinase activity mediated by signal transducer and activator of transcription 5A (STAT5A) in CR prostate cancer. Additionally, we uncovered high STAT5A kinase activity already in regressing ADL xenografts, before renewed CR growth was evidenced. Finally, since increased STAT5A kinase activity also was detected after exposing prostate carcinoma cells to hypoxia, we propose long-term ADT to induce tumor hypoxia and stimulate STAT5A kinase activity, subsequently leading to renewed CR tumor growth. Hence, the study detected STAT5A as a candidate to be further investigated for its potential as marker of advanced prostate cancer and as possible therapeutic target protein. PMID:23675504

  12. Signal Sensing and Transduction by Histidine Kinases as Unveiled through Studies on a Temperature Sensor.

    PubMed

    Abriata, Luciano A; Albanesi, Daniela; Dal Peraro, Matteo; de Mendoza, Diego

    2017-06-20

    Histidine kinases (HK) are the sensory proteins of two-component systems, responsible for a large fraction of bacterial responses to stimuli and environmental changes. Prototypical HKs are membrane-bound proteins that phosphorylate cognate response regulator proteins in the cytoplasm upon signal detection in the membrane or periplasm. HKs stand as potential drug targets but also constitute fascinating systems for studying proteins at work, specifically regarding the chemistry and mechanics of signal detection, transduction through the membrane, and regulation of catalytic outputs. In this Account, we focus on Bacillus subtilis DesK, a membrane-bound HK part of a two-component system that maintains appropriate membrane fluidity at low growth temperatures. Unlike most HKs, DesK has no extracytoplasmic signal-sensing domains; instead, sensing is carried out by 10 transmembrane helices (coming from two protomers) arranged in an unknown structure. The fifth transmembrane helix from each protomer connects, without any of the intermediate domains found in other HKs, into the dimerization and histidine phosphotransfer (DHp) domain located in the cytoplasm, which is followed by the ATP-binding domains (ABD). Throughout the years, genetic, biochemical, structural, and computational studies on wild-type, mutant, and truncated versions of DesK allowed us to dissect several aspects of DesK's functioning, pushing forward a more general understanding of its own structure/function relationships as well as those of other HKs. We have shown that the sensing mechanism is rooted in temperature-dependent membrane properties, most likely a combination of thickness, fluidity, and water permeability, and we have proposed possible mechanisms by which DesK senses these properties and transduces the signals. X-ray structures and computational models have revealed structural features of TM and cytoplasmic regions in DesK's kinase- and phosphatase-competent states. Biochemical and genetic

  13. Targeting kinase signaling pathways with constrained peptide scaffolds

    PubMed Central

    Hanold, Laura E.; Fulton, Melody D.; Kennedy, Eileen J.

    2017-01-01

    Kinases are amongst the largest families in the human proteome and serve as critical mediators of a myriad of cell signaling pathways. Since altered kinase activity is implicated in a variety of pathological diseases, kinases have become a prominent class of proteins for targeted inhibition. Although numerous small molecule and antibody-based inhibitors have already received clinical approval, several challenges may still exist with these strategies including resistance, target selection, inhibitor potency and in vivo activity profiles. Constrained peptide inhibitors have emerged as an alternative strategy for kinase inhibition. Distinct from small molecule inhibitors, peptides can provide a large binding surface area that allows them to bind shallow protein surfaces rather than defined pockets within the target protein structure. By including chemical constraints within the peptide sequence, additional benefits can be bestowed onto the peptide scaffold such as improved target affinity and target selectivity, cell permeability and proteolytic resistance. In this review, we highlight examples of diverse chemistries that are being employed to constrain kinase-targeting peptide scaffolds and highlight their application to modulate kinase signaling as well as their potential clinical implications. PMID:28185915

  14. IL-6 secreted by cancer-associated fibroblasts promotes epithelial-mesenchymal transition and metastasis of gastric cancer via JAK2/STAT3 signaling pathway

    PubMed Central

    Li, Jie; Yu, Zhenjia; Wang, Xiaofeng; Li, Jiaanfang; Li, Chen; Yan, Min; Zhu, Zhenggang; Liu, Bingya; Su, Liping

    2017-01-01

    Cancer-associated fibroblasts (CAFs), as the activated fibroblasts in tumor stroma, are important modifiers of tumor progression. However, the molecular mechanisms underlying the tumor-promoting properties of CAFs in gastric cancer remain unclear. Here, we show that CAFs isolated from gastric cancer produce significant amounts of interleukin-6 (IL-6). CAFs enhances the migration and EMT of gastric cancer cells through the secretion of IL-6 that activates Janus kinase 2/signal transducers and activators of transcription (JAK2/STAT3) pathway in gastric cancer cells, while deprivation of IL-6 using a neutralizing antibody or inhibition of JAK/STAT3 pathway with specific inhibitor AG490 markedly attenuates these phenotypes in gastric cancer cells induced by CAFs. Moreover, silencing IL-6 expression in CAFs or inhibiting JAK2/STAT3 pathway in gastric cancer cells impairs tumor peritoneal metastasis induced by CAFs in vivo. Taken together, these results suggest that CAFs in the tumor microenvironment promote the progression of gastric cancer through IL-6/JAK2/STAT3 signaling, and IL-6 targeted therapy could be a complementary approach against gastric cancer by exerting their action on stromal fibroblasts. PMID:28186964

  15. Apelin Increases Cardiac Contractility via Protein Kinase Cε- and Extracellular Signal-Regulated Kinase-Dependent Mechanisms

    PubMed Central

    Perjés, Ábel; Skoumal, Réka; Tenhunen, Olli; Kónyi, Attila; Simon, Mihály; Horváth, Iván G.; Kerkelä, Risto; Ruskoaho, Heikki; Szokodi, István

    2014-01-01

    Background Apelin, the endogenous ligand for the G protein-coupled apelin receptor, is an important regulator of the cardiovascular homoeostasis. We previously demonstrated that apelin is one of the most potent endogenous stimulators of cardiac contractility; however, its underlying signaling mechanisms remain largely elusive. In this study we characterized the contribution of protein kinase C (PKC), extracellular signal-regulated kinase 1/2 (ERK1/2) and myosin light chain kinase (MLCK) to the positive inotropic effect of apelin. Methods and Results In isolated perfused rat hearts, apelin increased contractility in association with activation of prosurvival kinases PKC and ERK1/2. Apelin induced a transient increase in the translocation of PKCε, but not PKCα, from the cytosol to the particulate fraction, and a sustained increase in the phosphorylation of ERK1/2 in the left ventricle. Suppression of ERK1/2 activation diminished the apelin-induced increase in contractility. Although pharmacological inhibition of PKC attenuated the inotropic response to apelin, it had no effect on ERK1/2 phosphorylation. Moreover, the apelin-induced positive inotropic effect was significantly decreased by inhibition of MLCK, a kinase that increases myofilament Ca2+ sensitivity. Conclusions Apelin increases cardiac contractility through parallel and independent activation of PKCε and ERK1/2 signaling in the adult rat heart. Additionally MLCK activation represents a downstream mechanism in apelin signaling. Our data suggest that, in addition to their role in cytoprotection, modest activation of PKCε and ERK1/2 signaling improve contractile function, therefore these pathways represent attractive possible targets in the treatment of heart failure. PMID:24695532

  16. Janus Monolayer Transition-Metal Dichalcogenides.

    PubMed

    Zhang, Jing; Jia, Shuai; Kholmanov, Iskandar; Dong, Liang; Er, Dequan; Chen, Weibing; Guo, Hua; Jin, Zehua; Shenoy, Vivek B; Shi, Li; Lou, Jun

    2017-08-22

    The crystal configuration of sandwiched S-Mo-Se structure (Janus SMoSe) at the monolayer limit has been synthesized and carefully characterized in this work. By controlled sulfurization of monolayer MoSe 2 , the top layer of selenium atoms is substituted by sulfur atoms, while the bottom selenium layer remains intact. The structure of this material is systematically investigated by Raman, photoluminescence, transmission electron microscopy, and X-ray photoelectron spectroscopy and confirmed by time-of-flight secondary ion mass spectrometry. Density functional theory (DFT) calculations are performed to better understand the Raman vibration modes and electronic structures of the Janus SMoSe monolayer, which are found to correlate well with corresponding experimental results. Finally, high basal plane hydrogen evolution reaction activity is discovered for the Janus monolayer, and DFT calculation implies that the activity originates from the synergistic effect of the intrinsic defects and structural strain inherent in the Janus structure.

  17. Double anisotropic electrically conductive flexible Janus-typed membranes.

    PubMed

    Li, Xiaobing; Ma, Qianli; Tian, Jiao; Xi, Xue; Li, Dan; Dong, Xiangting; Yu, Wensheng; Wang, Xinlu; Wang, Jinxian; Liu, Guixia

    2017-12-07

    Novel type III anisotropic conductive films (ACFs), namely flexible Janus-typed membranes, were proposed, designed and fabricated for the first time. Flexible Janus-typed membranes composed of ordered Janus nanobelts were constructed by electrospinning, which simultaneously possess fluorescence and double electrically conductive anisotropy. For the fabrication of the Janus-typed membrane, Janus nanobelts comprising a conductive side and an insulative-fluorescent side were primarily fabricated, and then the Janus nanobelts are arranged into parallel arrays using an aluminum rotary drum as the collector to obtain a single anisotropically conductive film. Subsequently, a secondary electrospinning process was applied to the as-prepared single anisotropically conductive films to acquire the final Janus-typed membrane. For this Janus-typed membrane, namely its left-to-right structure, anisotropic electrical conduction synchronously exists on both sides, and furthermore, the two electrically conductive directions are perpendicular. By modulating the amount of Eu(BA) 3 phen complex and conducting polyaniline (PANI), the characteristics and intensity of the fluorescence-electricity dual-function in the membrane can be tuned. The high integration of this peculiar Janus-typed membrane with simultaneous double electrically conductive anisotropy-fluorescent dual-functionality is successfully realized in this study. This design philosophy and preparative technique will provide support for the design and construction of new types of special nanostructures with multi-functionality.

  18. The nano-TiO2 exposure can induce hepatic inflammation involving in a JAK-STAT signalling pathway

    NASA Astrophysics Data System (ADS)

    Hong, Jie; Hong, Fashui; Ze, Yuguan; Zhang, Yu-Qing

    2016-06-01

    TiO2 nanoparticles (TiO2 NPs) have unique physiochemical properties and thus are widely used in daily life. However, these nanoparticles also have potential toxic effects in humans and animals, and the issue of the security TiO2 NPs has also gained prominence. In this article, mice were administered a gavage instillation of 2.5, 5, or 10 mg/kg body weight TiO2 NPs (5-6 nm) for 90 days. We investigated whether TiO2 NPs activate the JAK-STAT signalling pathway, causing nano-TiO2-induced hepatic toxicity. The results demonstrated that with increasing doses of TiO2 NPs the body weights of the mice body decreased, and the liver index, liver dysfunction, infiltration of inflammatory cells, and hepatocyte apoptosis and necrosis increased. Moreover, liver inflammation was accompanied by increased expression of Janus kinase 2, the signal transducers and activators of transcription 3, interleukin-6, cyclooxygenase-2, neutrophil gelatinase-associated lipocalin, purinergic receptor-7, and epithelial neutrophil-activating protein-78 and decreased expression of suppressors of cytokine signalling-1, peroxisome proliferator-activated receptor-γ, and peroxisome proliferator-activated receptor gamma coactivator-1 alpha. In summary, the activation of the JAK-STAT pathway may be involved in the hepatic inflammation induced by chronic nano-TiO2 toxicity.

  19. Janus Monolayer Transition-Metal Dichalcogenides

    DOE PAGES

    Zhang, Jing; Jia, Shuai; Kholmanov, Iskandar; ...

    2017-08-03

    In this work, the crystal configuration of sandwiched S–Mo–Se structure (Janus SMoSe) at the monolayer limit has been synthesized and carefully characterized. By controlled sulfurization of monolayer MoSe 2, the top layer of selenium atoms is substituted by sulfur atoms, while the bottom selenium layer remains intact. Furthermore, the structure of this material is systematically investigated by Raman, photoluminescence, transmission electron microscopy, and X-ray photoelectron spectroscopy and confirmed by time-of-flight secondary ion mass spectrometry. Density functional theory (DFT) calculations are performed to better understand the Raman vibration modes and electronic structures of the Janus SMoSe monolayer, which are found tomore » correlate well with corresponding experimental results. Finally, high basal plane hydrogen evolution reaction activity is discovered for the Janus monolayer, and DFT calculation implies that the activity originates from the synergistic effect of the intrinsic defects and structural strain inherent in the Janus structure.« less

  20. Protein Tyrosine Kinase Signaling During Oocyte Maturation and Fertilization

    PubMed Central

    McGinnis, Lynda K.; Carroll, David J.; Kinsey, William H.

    2011-01-01

    The oocyte is a highly specialized cell capable of accumulating and storing energy supplies as well as maternal transcripts and pre-positioned signal transduction components needed for zygotic development, undergoing meiosis under control of paracrine signals from the follicle, fusing with a single sperm during fertilization, and zygotic development. The oocyte accomplishes this diverse series of events by establishing an array of signal transduction pathway components that include a select collection of protein tyrosine kinases (PTKs) that are expressed at levels significantly higher than most other cell types. This array of PTKs includes cytosolic kinases such as SRC-family PTKs (FYN and YES), and FAK kinases, as well as FER. These kinases typically exhibit distinct patterns of localization and in some cases are translocated from one subcellular compartment to another during meiosis. Significant differences exist in the extent to which PTK-mediated pathways are used by oocytes from species that fertilize externally versus internally. The PTK activation profiles as well as calcium signaling pattern seems to correlate with the extent to which a rapid block to polyspermy is required by the biology of each species. Suppression of each of the SRC-family PTKs as well as FER kinase results in failure of meiotic maturation or zygote development, indicating that these PTKs are important for oocyte quality and developmental potential. Future studies will hopefully reveal the extent to which these factors impact clinical assisted reproductive techniques in domestic animals and humans. PMID:21681843

  1. C-Mannosylation of thrombopoietin receptor (c-Mpl) regulates thrombopoietin-dependent JAK-STAT signaling.

    PubMed

    Sasazawa, Yukiko; Sato, Natsumi; Suzuki, Takehiro; Dohmae, Naoshi; Simizu, Siro

    The thrombopoietin receptor, also known as c-Mpl, is a member of the cytokine superfamily, which regulates the differentiation of megakaryocytes and formation of platelets by binding to its ligand, thrombopoietin (TPO), through Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling. The loss-of-function mutations of c-Mpl cause severe thrombocytopenia due to impaired megakaryocytopoiesis, and gain-of-function mutations cause thrombocythemia. c-Mpl contains two Trp-Ser-Xaa-Trp-Ser (Xaa represents any amino acids) sequences, which are characteristic sequences of type I cytokine receptors, corresponding to C-mannosylation consensus sequences: Trp-Xaa-Xaa-Trp/Cys. C-mannosylation is a post-translational modification of tryptophan residue in which one mannose is attached to the first tryptophan residue in the consensus sequence via C-C linkage. Although c-Mpl contains some C-mannosylation sequences, whether c-Mpl is C-mannosylated or not has been uninvestigated. We identified that c-Mpl is C-mannosylated not only at Trp(269) and Trp(474), which are putative C-mannosylation site, but also at Trp(272), Trp(416), and Trp(477). Using C-mannosylation defective mutant of c-Mpl, the C-mannosylated tryptophan residues at four sites (Trp(269), Trp(272), Trp(474), and Trp(477)) are essential for c-Mpl-mediated JAK-STAT signaling. Our findings suggested that C-mannosylation of c-Mpl is a possible therapeutic target for platelet disorders. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Decursin chemosensitizes human multiple myeloma cells through inhibition of STAT3 signaling pathway.

    PubMed

    Kim, Hyun Jung; Kim, Sung-Moo; Park, Kyung-Ran; Jang, Hyeung-Jin; Na, Young-Soon; Ahn, Kyoo Seok; Kim, Sung-Hoon; Ahn, Kwang Seok

    2011-02-01

    Recent reports have indicated that decursin can induce apoptosis, suppress tumor growth, and inhibit angiogenesis. In this experiment, we investigated how decursin could potentiate the cytotoxic effects of bortezomib in human multiple myeloma cells. We found that decursin inhibited cell viability in U266, MM.1S and ARH77 cells, but not in peripheral blood mononuclear cells (PBMC). Decursin-induced apoptosis through the activation of caspase-8, -9, and -3 in U266 cells. This correlated with the down-regulating of cyclin D1, bcl-2, bcl-xL, survivin, and the vascular endothelial growth factor (VEGF), which are all regulated by the activation of signal transducers and the activator of transcription 3 (STAT3). Indeed, decursin inhibited constitutive STAT3 activation through inhibition of the activation of Janus-activated kinase 2 (JAK2) in U266 cells. In addition, decursin inhibited interleukin-6-inducible STAT3 activation in a time-dependent manner in MM.1S cells. Interestingly, decursin significantly potentiated the apoptotic effects of bortezomib in U266 cells. These effects of decursin were correlated with the suppression of constitutive STAT3 activation in U266 cells. Overall, these results suggest that decursin is a novel blocker of STAT3 activation and it may be a potential candidate for overcoming chemo-resistance through suppression of this signaling. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  3. UnPAKing the class differences among p21-activated kinases.

    PubMed

    Eswaran, Jeyanthy; Soundararajan, Meera; Kumar, Rakesh; Knapp, Stefan

    2008-08-01

    The p21-activated kinases (PAKs) are signal transducers, central to many vital cellular processes, including cell morphology, motility, survival, gene transcription and hormone signalling. The mammalian PAK family contains six serine/threonine kinases divided into two subgroups, group I (PAK 1-3) and group II (PAK4-6), based on their domain architecture and regulation. PAKs functioning as dynamic signalling nodes present themselves as attractive therapeutic targets in tumours, neurological diseases and infection. The recent findings across all PAKs, including newly reported structures, shed light on the cellular functions of PAKs, highlighting molecular mechanisms of activation, catalysis and substrate specificity. We believe that a comprehensive understanding of the entire PAK family is essential for developing strategies towards PAK-targeted therapeutics.

  4. Conventional protein kinase C-α (PKC-α) and PKC-β negatively regulate RIG-I antiviral signal transduction.

    PubMed

    Maharaj, Natalya P; Wies, Effi; Stoll, Andrej; Gack, Michaela U

    2012-02-01

    Retinoic acid-inducible gene I (RIG-I) is a key sensor for viral RNA in the cytosol, and it initiates a signaling cascade that leads to the establishment of an interferon (IFN)-mediated antiviral state. Because of its integral role in immune signaling, RIG-I activity must be precisely controlled. Recent studies have shown that RIG-I CARD-dependent signaling function is regulated by the dynamic balance between phosphorylation and TRIM25-induced K₆₃-linked ubiquitination. While ubiquitination of RIG-I is critical for RIG-I's ability to induce an antiviral IFN response, phosphorylation of RIG-I at S₈ or T₁₇₀ suppresses RIG-I signal-transducing activity under normal conditions. Here, we not only further define the roles of S₈ and T₁₇₀ phosphorylation for controlling RIG-I activity but also identify conventional protein kinase C-α (PKC-α) and PKC-β as important negative regulators of the RIG-I signaling pathway. Mutational analysis indicated that while the phosphorylation of S₈ or T₁₇₀ potently inhibits RIG-I downstream signaling, the dephosphorylation of RIG-I at both residues is necessary for optimal TRIM25 binding and ubiquitination-mediated RIG-I activation. Furthermore, exogenous expression, gene silencing, and specific inhibitor treatment demonstrated that PKC-α/β are the primary kinases responsible for RIG-I S₈ and T₁₇₀ phosphorylation. Coimmunoprecipitation showed that PKC-α/β interact with RIG-I under normal conditions, leading to its phosphorylation, which suppresses TRIM25 binding, RIG-I CARD ubiquitination, and thereby RIG-I-mediated IFN induction. PKC-α/β double-knockdown cells exhibited markedly decreased S₈/T₁₇₀ phosphorylation levels of RIG-I and resistance to infection by vesicular stomatitis virus. Thus, these findings demonstrate that PKC-α/β-induced RIG-I phosphorylation is a critical regulatory mechanism for controlling RIG-I antiviral signal transduction under normal conditions.

  5. Regulation of T cell homeostasis by JAKs and STATs.

    PubMed

    Ross, Jeremy A; Nagy, Zsuzsanna S; Cheng, Hanyin; Stepkowski, Stanislaw M; Kirken, Robert A

    2007-01-01

    Regulation of T cell homeostasis is critical for maintaining normal immune function. An imbalance in T cell proliferation can result in disorders ranging from cancer and autoimmunity to immunodeficiencies. Full activation of T cells requires three sequential signals, where signal 3, which is delivered by multiple cytokines, regulates proliferation, differentiation, and survival/death. Signaling from cytokines through their receptors is primarily delivered by two molecular families, namely Janus tyrosine kinases (JAKs) and signal transducers and activators of transcription (STATs). Invaluable knowledge about JAKs and STATs has arisen from studies of mice made genetically deficient in these molecules, analyses of tumor models, and studies of expression patterns by proteomics/genomics, which all have begun to define the role of JAKs and STATs in survival versus apoptosis. These findings also have suggested ways in which JAKs and STATs may be manipulated for therapeutic intervention in lymphoid-derived diseases. This review seeks to focus on the role of JAK tyrosine kinases and STAT transcription factors in mediating the lymphocyte life cycle and how they might be manipulated for therapeutic applications.

  6. Two homolog wheat Glycogen Synthase Kinase 3/SHAGGY--like kinases are involved in brassinosteroid signaling.

    PubMed

    Bittner, Thomas; Nadler, Sabine; Schulze, Eija; Fischer-Iglesias, Christiane

    2015-10-13

    Glycogen Synthase Kinase 3/SHAGGY-like kinases (GSKs) are multifunctional non-receptor ser/thr kinases. Plant GSKs are involved in hormonal signaling networks and are required for growth, development, light as well as stress responses. So far, most studies have been carried out on Arabidopsis or on other eudicotyledon GSKs. Here, we evaluated the role of TaSK1 and TaSK2, two homolog wheat (Triticum aestivum) GSKs, in brassinosteroid signaling. We explored in addition the physiological effects of brassinosteroids on wheat growth and development. A bin2-1 like gain-of-function mutation has been inserted respectively in one of the homoeologous gene copies of TaSK1 (TaSK1-A.2-1) and in one of the homoeologous gene copies of TaSK2 (TaSK2-A.2-1). Arabidopsis plants were transformed with these mutated gene copies. Severe dwarf phenotypes were obtained closely resembling those of Arabidopsis bin2-1 lines and Arabidopsis BR-deficient or BR-signaling mutants. Expression of BR downstream genes, SAUR-AC1, CPD and BAS1 was deregulated in TaSK1.2-1 and TaSK2.2-1 transgenic lines. Severe dwarf lines were partially rescued by Bikinin beforehand shown to inhibit TaSK kinase activity. This rescue was accompanied with changes in BR downstream gene expression levels. Wheat embryos and seedlings were treated with compounds interfering with BR signaling or modifying BR levels to gain insight into the role of brassinosteroids in wheat development. Embryonic axis and scutellum differentiation were impaired, and seedling growth responses were affected when embryos were treated with Epibrassinolides, Propiconazole, and Bikinin. In view of our findings, TaSKs are proposed to be involved in BR signaling and to be orthologous of Arabidopsis Clade II GSK3/SHAGGY-like kinases. Observed effects of Epibrassinolide, Propiconazole and Bikinin treatments on wheat embryos and seedlings indicate a role for BR signaling in embryonic patterning and seedling growth.

  7. Leptin signalling, obesity and prostate cancer: molecular and clinical perspective on the old dilemma.

    PubMed

    Alshaker, Heba; Sacco, Keith; Alfraidi, Albandri; Muhammad, Aun; Winkler, Mathias; Pchejetski, Dmitri

    2015-11-03

    The prevalence of global obesity is increasing. Obesity is associated with general cancer-related morbidity and mortality and is a known risk factor for development of specific cancers. A recent large systematic review of 24 studies based on meta-analysis of 11,149 patients with prostate cancer showed a significant correlation between obesity and the risk of advanced prostate cancer. Further, a sustained reduction in BMI correlates with a decreased risk of developing aggressive disease. On the other hand, the correlation between consuming different products and prostate cancer occurrence/risk is limited.Here, we review the role of adipose tissue from an endocrine perspective and outline the effect of adipokines on cancer metabolism, with particular focus on leptin. Leptin exerts its physiological and pathological effects through modification of intracellular signalling, most notably activating the Janus kinase (JAK) 2/signal transducer and activator of transcription (STAT) 3 pathway and recently shown sphingolipid pathway. Both high levels of leptin in circulation and leptin receptor mutation are associated with prostate cancer risk in human patients; however, the in vivo mechanistic evidence is less conclusive.Given the complexity of metabolic cancer pathways, it is possible that leptin may have varying effects on prostate cancer at different stages of its development, a point that may be addressed by further epidemiological studies.

  8. Effects of Transducer Installation on Unsteady Pressure Measurements on Oscillating Blades

    NASA Technical Reports Server (NTRS)

    Lepicovsky, Jan

    2006-01-01

    Unsteady pressures were measured above the suction side of a blade that was oscillated to simulate blade stall flutter. Measurements were made at blade oscillation frequencies up to 500 Hz. Two types of miniature pressure transducers were used: surface-mounted flat custom-made, and conventional miniature, body-mounted transducers. The signals of the surface-mounted transducers are significantly affected by blade acceleration, whereas the signals of body-mounted transducers are practically free of this distortion. A procedure was introduced to correct the signals of surface-mounted transducers to rectify the signal distortion due to blade acceleration. The signals from body-mounted transducers, and corrected signals from surface-mounted transducers represent true unsteady pressure signals on the surface of a blade subjected to forced oscillations. However, the use of body-mounted conventional transducers is preferred for the following reasons: no signal corrections are needed for blade acceleration, the conventional transducers are noticeably less expensive than custom-made flat transducers, the survival rate of body-mounted transducers is much higher, and finally installation of body-mounted transducers does not disturb the blade surface of interest.

  9. Tunable signal processing in synthetic MAP kinase cascades.

    PubMed

    O'Shaughnessy, Ellen C; Palani, Santhosh; Collins, James J; Sarkar, Casim A

    2011-01-07

    The flexibility of MAPK cascade responses enables regulation of a vast array of cell fate decisions, but elucidating the mechanisms underlying this plasticity is difficult in endogenous signaling networks. We constructed insulated mammalian MAPK cascades in yeast to explore how intrinsic and extrinsic perturbations affect the flexibility of these synthetic signaling modules. Contrary to biphasic dependence on scaffold concentration, we observe monotonic decreases in signal strength as scaffold concentration increases. We find that augmenting the concentration of sequential kinases can enhance ultrasensitivity and lower the activation threshold. Further, integrating negative regulation and concentration variation can decouple ultrasensitivity and threshold from the strength of the response. Computational analyses show that cascading can generate ultrasensitivity and that natural cascades with different kinase concentrations are innately biased toward their distinct activation profiles. This work demonstrates that tunable signal processing is inherent to minimal MAPK modules and elucidates principles for rational design of synthetic signaling systems. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Signal Transduction in Histidine Kinases: Insights from New Structures

    PubMed Central

    Bhate, Manasi P.; Molnar, Kathleen S.; Goulian, Mark; DeGrado, William F.

    2015-01-01

    Histidine kinases (HKs) are major players in bacterial signaling. There has been an explosion of new HK crystal structures in the last five years. We globally analyze the structures of HKs to yield insights into the mechanisms by which signals are transmitted to and across protein structures in this family. We interpret known enzymological data in the context of new structural data to show how asymmetry across the dimer interface is a key feature of signal transduction in HKs, and discuss how different HK domains undergo asymmetric-to-symmetric transitions during signal transduction and catalysis. A thermodynamic framework for signaling that encompasses these various properties is presented and the consequences of weak thermodynamic coupling are discussed. The synthesis of observations from enzymology, structural biology, protein engineering and thermodynamics paves the way for a deeper molecular understanding of histidine kinase signal transduction. PMID:25982528

  11. Ocean Drilling Program: Janus Web Database

    Science.gov Websites

    in Janus Data Types and Examples Leg 199, sunrise. Janus Web Database ODP and IODP data are stored in as time permits (see Database Overview for available data). Data are available to everyone. There are

  12. Adaptor proteins in protein kinase C-mediated signal transduction.

    PubMed

    Schechtman, D; Mochly-Rosen, D

    2001-10-01

    Spatial and temporal organization of signal transduction is essential in determining the speed and precision by which signaling events occur. Adaptor proteins are key to organizing signaling enzymes near their select substrates and away from others in order to optimize precision and speed of response. Here, we describe the role of adaptor proteins in determining the specific function of individual protein kinase C (PKC) isozymes. These isozyme-selective proteins were called collectively RACKs (receptors for activated C-kinase). The role of RACKs in PKC-mediated signaling was determined using isozyme-specific inhibitors and activators of the binding of each isozyme to its respective RACK. In addition to anchoring activated PKC isozymes, RACKs anchor other signaling enzymes. RACK1, the anchoring protein for activated betaIIPKC, binds for example, Src tyrosine kinase, integrin, and phosphodiesterase. RACK2, the epsilonPKC-specific RACK, is a coated-vesicle protein and thus is involved in vesicular release and cell-cell communication. Therefore, RACKs are not only adaptors for PKC, but also serve as adaptor proteins for several other signaling enzymes. Because at least some of the proteins that bind to RACKs, including PKC itself, regulate cell growth, modulating their interactions with RACKs may help elucidate signaling pathways leading to carcinogenesis and could result in the identification of novel therapeutic targets.

  13. Novel magnetic-fluorescent bifunctional Janus nanofiber membrane

    NASA Astrophysics Data System (ADS)

    Wang, Qiutong; Geng, Yuting; Li, Jianhao; Yin, Meizhen; Hu, Yiseng; Liu, Yangxiu; Pan, Kai

    2018-04-01

    Magnetic-fluorescent bifunctional materials have received global attention owing to their potential in many fields. Herein, we reported a novel magnetic-fluorescent bifunctional Janus nanofiber membrane (NFM) by adding the as-prepared magnetic CoFe2O4 nanoparticles into the polyacrylonitrile (PAN) side (m-PAN) and the fluorescent molecules of 1,8-naphthalene anhydride (1,8-NAD) into the polyvinylpyrrolidone (PVP) side (f-PVP) via electrospinning method. The obtained m-PAN/f-PVP Janus NFM exhibited excellent magnetic performance and high fluorescent properties due to the unique structure. Compared with the m-PAN/f-PVP composite NFM, the Janus NFM showed higher fluorescent performance because the fluorescent molecules were isolated from the magnetic nanoparticles. In addition, the Janus NFM not only maintain the good self-supporting state in water but also realize a directional movement attracted by a magnet. The unique structure of Janus nanofiber is of great importance and demonstrates great potential applications.

  14. Signaling Network Map of Endothelial TEK Tyrosine Kinase

    PubMed Central

    Sandhya, Varot K.; Singh, Priyata; Parthasarathy, Deepak; Kumar, Awinav; Gattu, Rudrappa; Mathur, Premendu Prakash; Mac Gabhann, F.; Pandey, Akhilesh

    2014-01-01

    TEK tyrosine kinase is primarily expressed on endothelial cells and is most commonly referred to as TIE2. TIE2 is a receptor tyrosine kinase modulated by its ligands, angiopoietins, to regulate the development and remodeling of vascular system. It is also one of the critical pathways associated with tumor angiogenesis and familial venous malformations. Apart from the vascular system, TIE2 signaling is also associated with postnatal hematopoiesis. Despite the involvement of TIE2-angiopoietin system in several diseases, the downstream molecular events of TIE2-angiopoietin signaling are not reported in any pathway repository. Therefore, carrying out a detailed review of published literature, we have documented molecular signaling events mediated by TIE2 in response to angiopoietins and developed a network map of TIE2 signaling. The pathway information is freely available to the scientific community through NetPath, a manually curated resource of signaling pathways. We hope that this pathway resource will provide an in-depth view of TIE2-angiopoietin signaling and will lead to identification of potential therapeutic targets for TIE2-angiopoietin associated disorders. PMID:25371820

  15. Entropic stochastic resonance of a self-propelled Janus particle

    NASA Astrophysics Data System (ADS)

    Liu, Zhenzhen; Du, Luchun; Guo, Wei; Mei, Dong-Cheng

    2016-10-01

    Entropic stochastic resonance is investigated when a self-propelled Janus particle moves in a double-cavity container. Numerical simulation results indicate the entropic stochastic resonance can survive even if there is no symmetry breaking in any direction. This is the essential distinction between the property of a self-propelled Janus particle and that of a passive Brownian particle, for the symmetry breaking is necessary for the entropic stochastic resonance of a passive Brownian particle. With the rotational noise intensity growing at small fixed noise intensity of translational motion, the signal power amplification increases monotonically towards saturation which also can be regarded as a kind of stochastic resonance effect. Besides, the increase in the natural frequency of the periodic driving depresses the degree of the stochastic resonance, whereas the rise in its amplitude enhances and then suppresses the behavior.

  16. Genetic variation in insulin-induced kinase signaling

    PubMed Central

    Wang, Isabel Xiaorong; Ramrattan, Girish; Cheung, Vivian G

    2015-01-01

    Individual differences in sensitivity to insulin contribute to disease susceptibility including diabetes and metabolic syndrome. Cellular responses to insulin are well studied. However, which steps in these response pathways differ across individuals remains largely unknown. Such knowledge is needed to guide more precise therapeutic interventions. Here, we studied insulin response and found extensive individual variation in the activation of key signaling factors, including ERK whose induction differs by more than 20-fold among our subjects. This variation in kinase activity is propagated to differences in downstream gene expression response to insulin. By genetic analysis, we identified cis-acting DNA variants that influence signaling response, which in turn affects downstream changes in gene expression and cellular phenotypes, such as protein translation and cell proliferation. These findings show that polymorphic differences in signal transduction contribute to individual variation in insulin response, and suggest kinase modulators as promising therapeutics for diseases characterized by insulin resistance. PMID:26202599

  17. Inhibition of DNA methyltransferase induces G2 cell cycle arrest and apoptosis in human colorectal cancer cells via inhibition of JAK2/STAT3/STAT5 signalling.

    PubMed

    Xiong, Hua; Chen, Zhao-Fei; Liang, Qin-Chuan; Du, Wan; Chen, Hui-Min; Su, Wen-Yu; Chen, Guo-Qiang; Han, Ze-Guang; Fang, Jing-Yuan

    2009-09-01

    DNA methyltransferase inhibitors (MTIs) have recently emerged as promising chemotherapeutic or preventive agents for cancer, despite their poorly characterized mechanisms of action. The present study shows that DNA methylation is integral to the regulation of SH2-containing protein tyrosine phosphatase 1 (SHP1) expression, but not for regulation of suppressors of cytokine signalling (SOCS)1 or SOCS3 in colorectal cancer (CRC) cells. SHP1 expression correlates with down-regulation of Janus kinase/signal transducers and activators of transcription (JAK2/STAT3/STAT5) signalling, which is mediated in part by tyrosine dephosphorylation events and modulation of the proteasome pathway. Up-regulation of SHP1 expression was achieved using a DNA MTI, 5-aza-2'-deoxycytidine (5-aza-dc), which also generated significant down-regulation of JAK2/STAT3/STAT5 signalling. We demonstrate that 5-aza-dc suppresses growth of CRC cells, and induces G2 cell cycle arrest and apoptosis through regulation of downstream targets of JAK2/STAT3/STAT5 signalling including Bcl-2, p16(ink4a), p21(waf1/cip1) and p27(kip1). Although 5-aza-dc did not significantly inhibit cell invasion, 5-aza-dc did down-regulate expression of focal adhesion kinase and vascular endothelial growth factor in CRC cells. Our results demonstrate that 5-aza-dc can induce SHP1 expression and inhibit JAK2/STAT3/STAT5 signalling. This study represents the first evidence towards establishing a mechanistic link between inhibition of JAK2/STAT3/STAT5 signalling and the anticancer action of 5-aza-dc in CRC cells that may lead to the use of MTIs as a therapeutic intervention for human colorectal cancer.

  18. Differential insulin receptor substrate-1 (IRS1)-related modulation of neuropeptide Y and proopiomelanocortin expression in nondiabetic and diabetic IRS2-/- mice.

    PubMed

    Burgos-Ramos, Emma; González-Rodríguez, Agueda; Canelles, Sandra; Baquedano, Eva; Frago, Laura M; Revuelta-Cervantes, Jesús; Gómez-Ambrosi, Javier; Frühbeck, Gema; Chowen, Julie A; Argente, Jesús; Valverde, Angela M; Barrios, Vicente

    2012-03-01

    Insulin resistance and type 2 diabetes correlate with impaired leptin and insulin signaling. Insulin receptor substrate-2 deficient (IRS2(-/-)) mice are an accepted model for the exploration of alterations in these signaling pathways and their relationship with diabetes; however, disturbances in hypothalamic signaling and the effect on neuropeptides controlling food intake remain unclear. Our aim was to analyze how leptin and insulin signaling may differentially affect the expression of hypothalamic neuropeptides regulating food intake and hypothalamic inflammation in diabetic (D) and nondiabetic (ND) IRS2(-/-) mice. We analyzed the activation of leptin and insulin targets by Western blotting and their association by immunoprecipitation, as well as the mRNA levels of neuropeptide Y (NPY), proopiomelanocortin, and inflammatory markers by real-time PCR and colocalization of forkhead box protein O1 (FOXO1) and NPY by double immunohistochemistry in the hypothalamus. Serum leptin and insulin levels and hypothalamic Janus kinase 2 and signal transducer and activator of transcription factor 3 activation were increased in ND IRS2(-/-) mice. IRS1 levels and its association with Janus kinase 2 and p85 and protein kinase B activation were increased in ND IRS2(-/-). Increased FOXO1 positively correlated with NPY mRNA levels in D IRS2(-/-) mice, with FOXO1 showing mainly nuclear localization in D IRS2(-/-) and cytoplasmic in ND IRS2(-/-) mice. D IRS2(-/-) mice exhibited higher hypothalamic inflammation markers than ND IRS2(-/-) mice. In conclusion, differential activation of these pathways and changes in the expression of NPY and inflammation may exert a protective effect against hypothalamic deregulation of appetite, suggesting that manipulation of these targets could be of interest in the treatment of insulin resistance and type 2 diabetes.

  19. IL-5 Induces Suspended Eosinophils to Undergo Unique Global Reorganization Associated with Priming

    PubMed Central

    Han, Shih-Tsung

    2014-01-01

    The experiments described herein define a unique program of polarization of suspended human eosinophils stimulated with IL-5 family cytokines. We found that eosinophil granules and the nucleus move in opposite directions to form, respectively, a granular compartment and the nucleopod, a specialized uropod occupied by the nucleus and covered with adhesion receptors, including P-selectin glycoprotein ligand-1, CD44, and activated αMβ2 integrin. Ligated IL-5 family receptors localize specifically at the tip of the nucleopod in proximity to downstream signaling partners Janus tyrosine kinase 2, signal transducer and activator of transcription-1 and -5, and extracellular signal–regulated kinase. Microscopy and effects of cytochalasin B and nocodazole indicate that remodeling of filamentous actin and reorientation of the microtubule network are required for eosinophil polarization and nucleopod formation. IL-5 induces persistent polarization and extracellular signal–regulated kinase redistribution that are associated with eosinophil priming, a robust response on subsequent stimulation with N-formyl-methionyl-leucyl-phenylalanine. Global reorganization of cytoskeleton, organelles, adhesion receptors, and signaling molecules likely facilitates vascular arrest, extravasation, migration, granule release, and survival of eosinophils entering inflamed tissues from the bloodstream. PMID:24156300

  20. Electronic scanning pressure measuring system and transducer package

    NASA Technical Reports Server (NTRS)

    Coe, C. F. (Inventor); Parra, G. T.

    1984-01-01

    An electronic scanning pressure system that includes a plurality of pressure transducers is examined. A means obtains an electrical signal indicative of a pressure measurement from each of the plurality of pressure transducers. A multiplexing means is connected for selectivity supplying inputs from the plurality of pressure transducers to the signal obtaining means. A data bus connects the plurality of pressure transducers to the multiplexing means. A latch circuit is connected to supply control inputs to the multiplexing means. An address bus is connected to supply an address signal of a selected one of the plurality of pressure transducers to the latch circuit. In operation, each of the pressure transducers is successively scanned by the multiplexing means in response to address signals supplied on the address bus to the latch circuit.

  1. Inorganic Janus particles for biomedical applications

    PubMed Central

    Schick, Isabel; Lorenz, Steffen; Gehrig, Dominik; Tenzer, Stefan; Storck, Wiebke; Fischer, Karl; Strand, Dennis; Laquai, Frédéric

    2014-01-01

    Summary Based on recent developments regarding the synthesis and design of Janus nanoparticles, they have attracted increased scientific interest due to their outstanding properties. There are several combinations of multicomponent hetero-nanostructures including either purely organic or inorganic, as well as composite organic–inorganic compounds. Janus particles are interconnected by solid state interfaces and, therefore, are distinguished by two physically or chemically distinct surfaces. They may be, for instance, hydrophilic on one side and hydrophobic on the other, thus, creating giant amphiphiles revealing the endeavor of self-assembly. Novel optical, electronic, magnetic, and superficial properties emerge in inorganic Janus particles from their dimensions and unique morphology at the nanoscale. As a result, inorganic Janus nanoparticles are highly versatile nanomaterials with great potential in different scientific and technological fields. In this paper, we highlight some advances in the synthesis of inorganic Janus nanoparticles, focusing on the heterogeneous nucleation technique and characteristics of the resulting high quality nanoparticles. The properties emphasized in this review range from the monodispersity and size-tunability and, therefore, precise control over size-dependent features, to the biomedical application as theranostic agents. Hence, we show their optical properties based on plasmonic resonance, the two-photon activity, the magnetic properties, as well as their biocompatibility and interaction with human blood serum. PMID:25551063

  2. c-Jun controls the efficiency of MAP kinase signaling by transcriptional repression of MAP kinase phosphatases

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sprowles, Amy; Robinson, Dan; Wu Yimi

    2005-08-15

    The mammalian JNK signaling pathway regulates the transcriptional response of cells to environmental stress, including UV irradiation. This signaling pathway is composed of a classical MAP kinase cascade; activation results in phosphorylation of the transcription factor substrates c-Jun and ATF2, and leads to changes in gene expression. The defining components of this pathway are conserved in the fission yeast S. pombe, where the genetic studies have shown that the ability of the JNK homolog Spc1 to be activated in response to UV irradiation is dependent on the presence of the transcription factor substrate Atf1. We have used genetic analysis tomore » define the role of c-Jun in activation of the mammalian JNK signaling pathway. Our results show that optimal activation of JNK requires the presence of its transcription factor substrate c-Jun. Mutational analysis shows that the ability of c-Jun to support efficient activation of JNK requires the ability of Jun to bind DNA, suggesting a transcriptional mechanism. Consistent with this, we show that c-Jun represses the expression of several MAP kinase phosphatases. In the absence of c-Jun, the increased expression of MAP kinase phosphatases leads to impaired activation of the ERK, JNK, and p38 MAP kinases after pathway activation. The results show that one function of c-Jun is to regulate the efficiency of signaling by the ERK, p38, and JNK MAP kinases, a function that is likely to affect cellular responses to many different stimuli.« less

  3. Safety, tolerability, and pharmacokinetics of single oral doses of tofacitinib, a Janus kinase inhibitor, in healthy volunteers.

    PubMed

    Krishnaswami, Sriram; Boy, Mary; Chow, Vincent; Chan, Gary

    2015-03-01

    Tofacitinib is an oral Janus kinase inhibitor. This randomized, double-blind, parallel-group, placebo-controlled study was the first evaluation of tofacitinib in humans. The objectives were to characterize the safety and tolerability, pharmacokinetics (PK), and pharmacodynamics of escalating single tofacitinib doses in healthy subjects. Tofacitinib (0.1, 0.3, 1, 3, 10, 30, 60, and 100 mg) or placebo was administered as oral powder for constitution. For each dose, 7-9 subjects were randomized to tofacitinib and 3-5 subjects to placebo. Ninety-five males and females (age range 19-45) completed the study. Forty-nine treatment-emergent all-causality adverse events (AEs) were observed; nausea and headache were the most frequently reported. Tofacitinib PK was characterized by rapid absorption (time to peak serum concentration [Tmax ] 0.5-1 hour), rapid elimination (mean terminal half-lives 2.3-3.1 hours), and dose-proportional systemic exposures (peak serum concentration [Cmax ] and area under the serum concentration-time curve from time zero to infinity [AUC0-∞ ]). No appreciable correlation was observed between tofacitinib dose and lymphocyte subset counts. Single-dose tofacitinib up to 100 mg in healthy subjects had a safety profile of mostly mild AEs, and no deaths, serious AEs, severe AEs or discontinuations due to AEs. © 2014, The American College of Clinical Pharmacology.

  4. Adiponectin inhibits leptin signaling via multiple mechanisms to exert protective effects against hepatic fibrosis

    PubMed Central

    HANDY, Jeffrey A.; FU, Ping P.; KUMAR, Pradeep; MELLS, Jamie E.; SHARMA, Shvetank; SAXENA, Neeraj K.; ANANIA, Frank A.

    2011-01-01

    SYNOPSIS Adiponectin is protective against hepatic fibrosis, while leptin promotes fibrosis. In hepatic stellate cells (HSCs), leptin signals via a Janus Kinase 2/Signal Transducers and Activators of Transcription 3 (Jak2/Stat3) pathway, producing effects that enhance extracellular matrix deposition. Suppressors of Cytokine Signaling-3 (SOCS-3) and Protein Tyrosine Phosphatase-1B (PTP1B) are both negative regulators of Jak/Stat signaling, and recent studies demonstrated a role for adiponectin in regulating SOCS-3 expression. In this study we investigated mechanisms whereby adiponectin dampens leptin signaling and prevents excess ECM production. We treated culture-activated rat HSCs with recombinant adiponectin, leptin, both or neither, and also treated adiponectin knockout (Ad−/−) and wild-type mice with leptin and/or carbon tetrachloride (CCl4), or saline. We analyzed Jak2 and Ob-Rb phosphorylation, and PTP1B expression and activity. We also explored potential mechanisms through which adiponectin regulates SOCS-3/Ob-Rb association. Adiponectin inhibited leptin-stimulated Jak2 activation and Ob-Rb phosphorylation in HSCs, while both were increased in Ad−/− mice. Adiponectin stimulated PTP1B expression and activity, in vitro, while PTP1B expression was lower in Ad−/−mice than in wild-type mice. Adiponectin also promoted SOCS-3/Ob-R association, and blocked leptin-stimulated formation of extracellular TIMP-1/MMP-1 complexes, in vitro. These data suggest two novel mechanisms whereby adiponectin inhibits hepatic fibrosis: by promoting binding of SOCS-3 to Ob-Rb, and stimulating PTP1B expression and activity, thus inhibiting Jak2-Stat3 signaling at multiple points. PMID:21846328

  5. Receptor for macrophage colony-stimulating factor transduces a signal decreasing erythroid potential in the multipotent hematopoietic EML cell line.

    PubMed

    Pawlak, G; Grasset, M F; Arnaud, S; Blanchet, J P; Mouchiroud, G

    2000-10-01

    To test the hypothesis that hematopoietic growth factors may influence lineage choice in pluripotent progenitor cells, we investigated the effects of macrophage colony-stimulating factor (M-CSF) on erythroid and myeloid potentials of multipotent EML cells ectopically expressing M-CSF receptor (M-CSFR). EML cells are stem cell factor (SCF)-dependent murine cells that give rise spontaneously to pre-B cells, burst-forming unit erythroid (BFU-E), and colony-forming unit granulocyte macrophage (CFU-GM). We determined BFU-E and CFU-GM frequencies among EML cells transduced with murine M-CSFR, human M-CSFR, or chimeric receptors, and cultivated in the presence of SCF, M-CSF, or both growth factors. Effects of specific inhibitors of signaling molecules were investigated. EML cells transduced with murine M-CSFR proliferated in response to M-CSF but also exhibited a sharp and rapid decrease in BFU-E frequency associated with an increase in CFU-GM frequency. In contrast, EML cells expressing human M-CSFR proliferated in response to M-CSF without any changes in erythroid or myeloid potential. Using chimeric receptors between human and murine M-CSFR, we showed that the effects of M-CSF on EML cell differentiation potential are mediated by a large region in the intracellular domain of murine M-CSFR. Furthermore, phospholipase C (PLC) inhibitor U73122 interfered with the negative effects of ligand-activated murine M-CSFR on EML cell erythroid potential. We propose that signaling pathways activated by tyrosine kinase receptors may regulate erythroid potential and commitment decisions in multipotent progenitor cells and that PLC may play a key role in this process.

  6. Liquid crystal Janus emulsion droplets: preparation, tumbling, and swimming.

    PubMed

    Jeong, Joonwoo; Gross, Adam; Wei, Wei-Shao; Tu, Fuquan; Lee, Daeyeon; Collings, Peter J; Yodh, A G

    2015-09-14

    This study introduces liquid crystal (LC) Janus droplets. We describe a process for the preparation of these droplets, which consist of nematic LC and polymer compartments. The process employs solvent-induced phase separation in emulsion droplets generated by microfluidics. The droplet morphology was systematically investigated and demonstrated to be sensitive to the surfactant concentration in the background phase, the compartment volume ratio, and the possible coalescence of multiple Janus droplets. Interestingly, the combination of a polymer and an anisotropic LC introduces new functionalities into Janus droplets, and these properties lead to unusual dynamical behaviors. The different densities and solubilities of the two compartments produce gravity-induced alignment, tumbling, and directional self-propelled motion of Janus droplets. LC Janus droplets with remarkable optical properties and dynamical behaviors thus offer new avenues for applications of Janus colloids and active soft matter.

  7. Knocking off the suppressors of cytokine signaling (SOCS): their roles in mammalian pregnancy.

    PubMed

    Fitzgerald, Justine S; Toth, Bettina; Jeschke, Udo; Schleussner, Ekkehard; Markert, Udo R

    2009-12-01

    This review discusses the possible role of the suppressor of cytokine signaling (SOCS) proteins in mammalian reproduction. SOCS are regulatory proteins that are rapidly transcribed in response to intracellular Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling, a cascade governing biological functions including cytokine-induced immunological responses and reproductive processes. For instance STAT3 appears to mediate trophoblast invasion induced by LIF. The SOCS family includes 8 members (cytokine-inducible SH2 protein [CIS] and SOCS1-7) that orchestrate distinct reactions by antagonizing STAT activation. Emerging evidence points to a role of some family members in synchronizing Th1/Th2 cell profiles, the balance in which is considered vital to pregnancy maintenance. The reproductive phenotypes of mutant mice harboring targeted disruption of SOCS gene isoforms offer insights for reproductive immunology, trophoblast function and human pregnancy. CIS transgenic mice display impaired responses to IL-2 and resemble STAT5 deficient mice, except they are fertile. SOCS1 deficiency leads to an overabundance of IFNgamma signaling, yet SOCS1 null mutant mice are able to reproduce. Lack of SOCS3 is embryonically lethal due to placental insufficiency, while SOCS3 over-expression leads to elevated Th2 responses. SOCS3 seems to be vital for reproduction by regulating LIF-driven trophoblast differentiation. SOCS5 inhibits IL-4 signaling, yet the SOCS5 transgenic mouse has no conspicuous reproductive phenotype. SOCS-6 and SOCS-7 null mutant mice display growth retardation. In summary, SOCS proteins are avidly involved in fine regulation of immunological and other vital cellular responses. Many of the above phenotypes present contradictions to accepted reproductive immunological paradigms.

  8. Smad3 allostery links TGF-β receptor kinase activation to transcriptional control

    PubMed Central

    Qin, Bin Y.; Lam, Suvana S.; Correia, John J.; Lin, Kai

    2002-01-01

    Smad3 transduces the signals of TGF-βs, coupling transmembrane receptor kinase activation to transcriptional control. The membrane-associated molecule SARA (Smad Anchor for Receptor Activation) recruits Smad3 for phosphorylation by the receptor kinase. Upon phosphorylation, Smad3 dissociates from SARA and enters the nucleus, in which its transcriptional activity can be repressed by Ski. Here, we show that SARA and Ski recognize specifically the monomeric and trimeric forms of Smad3, respectively. Thus, trimerization of Smad3, induced by phosphorylation, simultaneously activates the TGF-β signal by driving Smad3 dissociation from SARA and sets up the negative feedback mechanism by Ski. Structural models of the Smad3/SARA/receptor kinase complex and Smad3/Ski complex provide insights into the molecular basis of regulation. PMID:12154125

  9. Signaling by Kit protein-tyrosine kinase--the stem cell factor receptor.

    PubMed

    Roskoski, Robert

    2005-11-11

    Signaling by stem cell factor and Kit, its receptor, plays important roles in gametogenesis, hematopoiesis, mast cell development and function, and melanogenesis. Moreover, human and mouse embryonic stem cells express Kit transcripts. Stem cell factor exists as both a soluble and a membrane-bound glycoprotein while Kit is a receptor protein-tyrosine kinase. The complete absence of stem cell factor or Kit is lethal. Deficiencies of either produce defects in red and white blood cell production, hypopigmentation, and sterility. Gain-of-function mutations of Kit are associated with several human neoplasms including acute myelogenous leukemia, gastrointestinal stromal tumors, and mastocytomas. Kit consists of an extracellular domain, a transmembrane segment, a juxtamembrane segment, and a protein kinase domain that contains an insert of about 80 amino acid residues. Binding of stem cell factor to Kit results in receptor dimerization and activation of protein kinase activity. The activated receptor becomes autophosphorylated at tyrosine residues that serve as docking sites for signal transduction molecules containing SH2 domains. The adaptor protein APS, Src family kinases, and Shp2 tyrosyl phosphatase bind to phosphotyrosine 568. Shp1 tyrosyl phosphatase and the adaptor protein Shc bind to phosphotyrosine 570. C-terminal Src kinase homologous kinase and the adaptor Shc bind to both phosphotyrosines 568 and 570. These residues occur in the juxtamembrane segment of Kit. Three residues in the kinase insert domain are phosphorylated and attract the adaptor protein Grb2 (Tyr703), phosphatidylinositol 3-kinase (Tyr721), and phospholipase Cgamma (Tyr730). Phosphotyrosine 900 in the distal kinase domain binds phosphatidylinositol 3-kinase which in turn binds the adaptor protein Crk. Phosphotyrosine 936, also in the distal kinase domain, binds the adaptor proteins APS, Grb2, and Grb7. Kit has the potential to participate in multiple signal transduction pathways as a result of

  10. Angiotensin II increases Pax-2 expression in fetal kidney cells via the AT2 receptor.

    PubMed

    Zhang, Shao-Ling; Moini, Babak; Ingelfinger, Julie R

    2004-06-01

    Although both the renin angiotensin system (RAS) and the paired homeobox 2 gene (Pax-2) seem critically important in renal organogenesis, whether and how they might interact has not been addressed. The present study asked whether a link between the RAS and Pax-2 exists in fetal renal cells, speculating that such an interaction, if present, might influence renal development. Embryonic kidney explants and embryonic renal cells (mouse late embryonic mesenchymal epithelial cells [MK4] and mouse early embryonic mesenchymal fibroblasts [MK3]) were used. Pax-2 protein and Pax-2 mRNA were detected by immunofluorescence, Western blot, reverse transcription-PCR, and real-time PCR. Angiotensin II (AngII) upregulated Pax-2 protein and Pax-2 mRNA expression via the AngII type 2 (AT(2)) receptor in MK4 but not in MK3 cells. The stimulatory effect of AngII on Pax-2 gene expression could be blocked by PD123319 (AT(2) inhibitor), AG 490 (a specific Janus kinase 2 inhibitor), and genistein (a tyrosine kinase inhibitor) but not by losartan (AT(1) inhibitor), SB203580 (specific p38 mitogen-activated protein kinase inhibitor), PD98059 (specific MEK inhibitor), SP600125 (JNK inhibitor), and diphenyleneiodonium chloride (an NADPH oxidase inhibitor). Moreover, embryonic kidney explants in culture confirmed that AngII upregulates Pax-2 gene expression via the AT(2) receptor. These studies demonstrate that the stimulatory effect of AngII on Pax-2 gene expression is mediated, at least in part, via the Janus kinase 2/signal transducers and activators of transcription signaling transduction pathway, suggesting that RAS and Pax-2 interactions may be important in renal development.

  11. Receptor kinase signalling in plants and animals: distinct molecular systems with mechanistic similarities.

    PubMed

    Cock, J Mark; Vanoosthuyse, Vincent; Gaude, Thierry

    2002-04-01

    Plant genomes encode large numbers of receptor kinases that are structurally related to the tyrosine and serine/threonine families of receptor kinase found in animals. Here, we describe recent advances in the characterisation of several of these plant receptor kinases at the molecular level, including the identification of receptor complexes, small polypeptide ligands and cytosolic proteins involved in signal transduction and receptor downregulation. Phylogenetic analysis indicates that plant receptor kinases have evolved independently of the receptor kinase families found in animals. This hypothesis is supported by functional studies that have revealed differences between receptor kinase signalling in plants and animals, particularly concerning their interactions with cytosolic proteins. Despite these dissimilarities, however, plant and animal receptor kinases share many common features, such as their single membrane-pass structure, their inclusion in membrane-associated complexes, the involvement of dimerisation and trans autophosphorylation in receptor activation, and the existence of inhibitors and phosphatases that downregulate receptor activity. These points of convergence may represent features that are essential for a functional receptor-kinase signalling system.

  12. Signal transduction through the IL-4 and insulin receptor families.

    PubMed

    Wang, L M; Keegan, A; Frankel, M; Paul, W E; Pierce, J H

    1995-07-01

    Activation of tyrosine kinase-containing receptors and intracellular tyrosine kinases by ligand stimulation is known to be crucial for mediating initial and subsequent events involved in mitogenic signal transduction. Receptors for insulin and insulin-like growth factor 1 (IGF-1) contain cytoplasmic tyrosine kinase domains that undergo autophosphorylation upon ligand stimulation. Activation of these receptors also leads to pronounced and rapid tyrosine phosphorylation of insulin receptor substrate 1 (IRS-1) in cells of connective tissue origin. A related substrate, designated 4PS, is similarly phosphorylated by insulin and IGF-1 stimulation in many hematopoietic cell types. IRS-1 and 4PS possess a number of tyrosine phosphorylation sites that are within motifs that bind specific SH2-containing molecules known to be involved in mitogenic signaling such as PI-3 kinase, SHPTP-2 (Syp) and Grb-2. Thus, they appear to act as docking substrates for a variety of signaling molecules. The majority of hematopoietic cytokines bind to receptors that do not possess intrinsic kinase activity, and these receptors have been collectively termed as members of the hematopoietin receptor superfamily. Despite their lack of tyrosine kinase domains, stimulation of these receptors has been demonstrated to activate intracellular kinases leading to tyrosine phosphorylation of multiple substrates. Recent evidence has demonstrated that activation of different members of the Janus family of tyrosine kinases is involved in mediating tyrosine phosphorylation events by specific cytokines. Stimulation of the interleukin 4 (IL-4) receptor, a member of the hematopoietin receptor superfamily, is thought to result in activation of Jak1, Jak3, and/or Fes tyrosine kinases.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. JAK/Stat signaling regulates heart precursor diversification in Drosophila

    PubMed Central

    Johnson, Aaron N.; Mokalled, Mayssa H.; Haden, Tom N.; Olson, Eric N.

    2011-01-01

    Intercellular signal transduction pathways regulate the NK-2 family of transcription factors in a conserved gene regulatory network that directs cardiogenesis in both flies and mammals. The Drosophila NK-2 protein Tinman (Tin) was recently shown to regulate Stat92E, the Janus kinase (JAK) and Signal transducer and activator of transcription (Stat) pathway effector, in the developing mesoderm. To understand whether the JAK/Stat pathway also regulates cardiogenesis, we performed a systematic characterization of JAK/Stat signaling during mesoderm development. Drosophila embryos with mutations in the JAK/Stat ligand upd or in Stat92E have non-functional hearts with luminal defects and inappropriate cell aggregations. Using strong Stat92E loss-of-function alleles, we show that the JAK/Stat pathway regulates tin expression prior to heart precursor cell diversification. tin expression can be subdivided into four phases and, in Stat92E mutant embryos, the broad phase 2 expression pattern in the dorsal mesoderm does not restrict to the constrained phase 3 pattern. These embryos also have an expanded pericardial cell domain. We show the E(spl)-C gene HLHm5 is expressed in a pattern complementary to tin during phase 3 and that this expression is JAK/Stat dependent. In addition, E(spl)-C mutant embryos phenocopy the cardiac defects of Stat92E embryos. Mechanistically, JAK/Stat signals activate E(spl)-C genes to restrict Tin expression and the subsequent expression of the T-box transcription factor H15 to direct heart precursor diversification. This study is the first to characterize a role for the JAK/Stat pathway during cardiogenesis and identifies an autoregulatory circuit in which tin limits its own expression domain. PMID:21965617

  14. A homolog of teleostean signal transducer and activator of transcription 3 (STAT3) from rock bream, Oplegnathus fasciatus: Structural insights, transcriptional modulation, and subcellular localization.

    PubMed

    Bathige, S D N K; Thulasitha, William Shanthakumar; Umasuthan, Navaneethaiyer; Jayasinghe, J D H E; Wan, Qiang; Nam, Bo-Hye; Lee, Jehee

    2017-04-01

    Signal transducer and activator of transcription 3 (STAT3) is one of the crucial transcription factors in the Janus kinase (JAK)/STAT signaling pathway, and it was previously considered as acute phase response factor. A number of interleukins (ILs) such as IL-5, IL-6, IL-9, IL-10, IL-12, and IL-22 are known to be involved in activation of STAT3. In addition, various growth factors and pathogenic or oxidative stresses mediate the activation of a wide range of functions via STAT3. In this study, a STAT3 homolog was identified and functionally characterized from rock bream (RbSTAT3), Oplegnathus fasciatus. In silico characterization revealed that the RbSTAT3 amino acid sequence shares highly conserved common domain architectural features including N-terminal domain, coiled coil domain, DNA binding domain, linker domain, and Src homology 2 (SH2) domains. In addition, a fairly conserved transcriptional activation domain (TAD) was located at the C-terminus. Comparison of RbSTAT3 with other counterparts revealed higher identities (>90%) with fish orthologs. The genomic sequence of RbSTAT3 was obtained from a bacterial artificial chromosome (BAC) library, and was identified as a multi-exonic gene (24 exons), as found in other vertebrates. Genomic structural comparison and phylogenetic studies have showed that the evolutionary routes of teleostean and non-teleostean vertebrates were distinct. Quantitative real time PCR (qPCR) analysis revealed that the spatial distribution of RbSTAT3 mRNA expression was ubiquitous and highly detectable in blood, heart, and liver tissues. Transcriptional modulation of RbSTAT3 was examined in blood and liver tissues after challenges with bacteria (Edwardsiella tarda and Streptococcus iniae), rock bream irido virus (RBIV), and immune stimulants (LPS and poly (I:C)). Significant changes in RbSTAT3 transcription were also observed in response to tissue injury. In addition, the transcriptional up-regulation of RbSTAT3 was detected in rock bream

  15. Raf kinase inhibitory protein: a signal transduction modulator and metastasis suppressor.

    PubMed

    Granovsky, Alexey E; Rosner, Marsha Rich

    2008-04-01

    Cells have a multitude of controls to maintain their integrity and prevent random switching from one biological state to another. Raf Kinase Inhibitory Protein (RKIP), a member of the phosphatidylethanolamine binding protein (PEBP) family, is representative of a new class of modulators of signaling cascades that function to maintain the "yin yang" or balance of biological systems. RKIP inhibits MAP kinase (Raf-MEK-ERK), G protein-coupled receptor (GPCR) kinase and NFkappaB signaling cascades. Because RKIP targets different kinases dependent upon its state of phosphorylation, RKIP also acts to integrate crosstalk initiated by multiple environmental stimuli. Loss or depletion of RKIP results in disruption of the normal cellular stasis and can lead to chromosomal abnormalities and disease states such as cancer. Since RKIP and the PEBP family have been reviewed previously, the goal of this analysis is to provide an update and highlight some of the unique features of RKIP that make it a critical player in the regulation of cellular signaling processes.

  16. Manganese- and 1-methyl-4-phenylpyridinium-induced neurotoxicity display differences in morphological, electrophysiological and genome-wide alterations: implications for idiopathic Parkinson's disease.

    PubMed

    Mythri, Rajeswara Babu; Raghunath, Narayana Reddy; Narwade, Santosh Chandrakant; Pandareesh, Mirazkar Dasharatha Rao; Sabitha, Kollarkandi Rajesh; Aiyaz, Mohamad; Chand, Bipin; Sule, Manas; Ghosh, Krittika; Kumar, Senthil; Shankarappa, Bhagyalakshmi; Soundararajan, Soundarya; Alladi, Phalguni Anand; Purushottam, Meera; Gayathri, Narayanappa; Deobagkar, Deepti Dileep; Laxmi, Thenkanidiyoor Rao; Srinivas Bharath, Muchukunte Mukunda

    2017-11-01

    Idiopathic Parkinson's disease and manganese-induced atypical parkinsonism are characterized by movement disorder and nigrostriatal pathology. Although clinical features, brain region involved and responsiveness to levodopa distinguish both, differences at the neuronal level are largely unknown. We studied the morphological, neurophysiological and molecular differences in dopaminergic neurons exposed to the Parkinson's disease toxin 1-methyl-4-phenylpyridinium ion (MPP + ) and manganese (Mn), followed by validation in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and Mn mouse models. Morphological analysis highlighted loss of neuronal processes in the MPP + and not the Mn model. Cellular network dynamics of dopaminergic neurons characterized by spike frequency and inter-spike intervals indicated major neuronal population (~ 93%) with slow discharge rates (0-5 Hz). While MPP + exposure suppressed the firing of these neurons, Mn neither suppressed nor elevated the neuronal activity. High-throughput transcriptomic analysis revealed up-regulation of 694 and 603 genes and down-regulation of 428 and 255 genes in the MPP + and Mn models respectively. Many differentially expressed genes were unique to either models and contributed to neuroinflammation, metabolic/mitochondrial function, apoptosis and nuclear function, synaptic plasticity, neurotransmission and cytoskeleton. Analysis of the Janus kinase-signal transducer and activator of transcription pathway with implications for neuritogenesis and neuronal proliferation revealed contrasting profile in both models. Genome-wide DNA methylomics revealed differences between both models and substantiated the epigenetic basis of the difference in the Janus kinase-signal transducer and activator of transcription pathway. We conclude that idiopathic Parkinson's disease and atypical parkinsonism have divergent neurotoxicological manifestation at the dopaminergic neuronal level with implications for pathobiology and evolution

  17. TC-PTP and PTP1B: Regulating JAK-STAT signaling, controlling lymphoid malignancies.

    PubMed

    Pike, Kelly A; Tremblay, Michel L

    2016-06-01

    Lymphoid malignancies are characterized by an accumulation of genetic lesions that act co-operatively to perturb signaling pathways and alter gene expression programs. The Janus kinases (JAK)-signal transducers and activators of transcription (STATs) pathway is one such pathway that is frequently mutated in leukemia and lymphoma. In response to cytokines and growth factors, a cascade of reversible tyrosine phosphorylation events propagates the JAK-STAT pathway from the cell surface to the nucleus. Activated STAT family members then play a fundamental role in establishing the transcriptional landscape of the cell. In leukemia and lymphoma, somatic mutations have been identified in JAK and STAT family members, as well as, negative regulators of the pathway. Most recently, inactivating mutations in the protein tyrosine phosphatase (PTP) genes PTPN1 (PTP1B) and PTPN2 (TC-PTP) were sequenced in B cell lymphoma and T cell acute lymphoblastic leukemia (T-ALL) respectively. The loss of PTP1B and TC-PTP phosphatase activity is associated with an increase in cytokine sensitivity, elevated JAK-STAT signaling, and changes in gene expression. As inactivation mutations in PTPN1 and PTPN2 are restricted to distinct subsets of leukemia and lymphoma, a future challenge will be to identify in which cellular contexts do they contributing to the initiation or maintenance of leukemogenesis or lymphomagenesis. As well, the molecular mechanisms by which PTP1B and TC-PTP loss co-operates with other genetic aberrations will need to be elucidated to design more effective therapeutic strategies. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Central Administration of 1-Deoxynojirimycin Attenuates Hypothalamic Endoplasmic Reticulum Stress and Regulates Food Intake and Body Weight in Mice with High-Fat Diet-Induced Obesity.

    PubMed

    Kim, Jongwan; Yun, Eun-Young; Quan, Fu-Shi; Park, Seung-Won; Goo, Tae-Won

    2017-01-01

    The α -glucosidase inhibitor, 1-deoxynojirimycin (DNJ), is widely used for its antiobesity and antidiabetic effects. Researchers have demonstrated that DNJ regulates body weight by increasing adiponectin levels, which affects energy intake and prevents diet-induced obesity. However, the mechanism by which centrally administered DNJ exerts anorexigenic effects has not been studied until now. We investigated the effect of DNJ in the hypothalamus of mice with high-fat diet-induced obesity. Results showed that intracerebroventricular (ICV) administration of DNJ reduced hypothalamic ER stress, which activated the leptin-induced Janus-activated kinase 2 (JAK2)/signal transducers and activators of transcription 3 (STAT3) signaling pathway to cause appetite suppression. We conclude that DNJ may reduce obesity by moderating feeding behavior and ER stress in the hypothalamic portion of the central nervous system (CNS).

  19. Effects of Janus kinase inhibitor tofacitinib on circulating serum amyloid A and interleukin-6 during treatment for rheumatoid arthritis

    PubMed Central

    Migita, K; Izumi, Y; Jiuchi, Y; Kozuru, H; Kawahara, C; Izumi, M; Sakai, T; Nakamura, M; Motokawa, S; Nakamura, T; Kawakami, A

    2014-01-01

    The Janus kinase inhibitor tofacitinib is currently being investigated as a disease-modifying agent in rheumatoid arthritis (RA). We investigated the in-vivo effects of tofacitinib treatment for 4 weeks on elevated circulating acute-phase serum amyloid (SAA) levels in 14 Japanese patients with RA. SAA levels fell from 110·5 ± 118·5 μg/ml (mean ± standard deviation) at treatment initiation to 15·3 ± 13·3 μg/ml after 4 weeks treatment with tofacitinib. The reduction in SAA levels was greater in patients receiving tofacitinib plus methotrexate compared with those receiving tofacitinib monotherapy. Tofacitinib was also associated with reduced serum interleukin (IL)-6, but had no effect on serum levels of soluble IL-6 receptor. Patients were divided into groups with adequate (normalization) and inadequate SAA responses (without normalization). Serum IL-6 levels were reduced more in the group with adequate SAA response compared with those with inadequate SAA response. These results suggest that tofacitinib down-regulates the proinflammatory cytokine, IL-6, accompanied by reduced serum SAA levels in patients with active RA. The ability to regulate elevated serum IL-6 and SAA levels may explain the anti-inflammatory activity of tofacitinib. PMID:24665995

  20. Foxc2 coordinates inflammation and browning of white adipose by leptin-STAT3-PRDM16 signal in mice.

    PubMed

    Gan, L; Liu, Z; Feng, F; Wu, T; Luo, D; Hu, C; Sun, C

    2018-02-01

    The objective of this study is to characterize the relationship between forkhead box C2 protein (Foxc2) and leptin under adipose inflammatory response. Lipopolysaccharide (LPS)-induced inflammatory model was conducted. Data from wild-type and ob/ob mice were used to compare the alternative role of leptin on Foxc2-mediated inflammation and browning. Transcriptional regulation and protein-protein interaction were analyzed by bioinformatics and proved by chromatin immunoprecipitation and co-immunoprecipitation experiment. Foxc2 and leptin correlated with inflammation and browning of white adipose tissue (WAT) in LPS-treated mice. Moreover, Foxc2-mediated inhibition of inflammation involved downstream activation of leptin signal and promoted WAT browning. We then determined CREB, the potential transcriptional factor of leptin, was required for Foxc2-mediated inflammation in the regulation of WAT browning. Foxc2 alleviated adipocyte inflammation by reducing leptin-mediated Janus-activated kinase 2/signal transducer and activator of transcription 3 (STAT3) pathway. Importantly, STAT3 physically interacted with PRDM16 and formed a complex to promote WAT browning. Exogenous Foxc2 overexpression also ameliorated inflammation and promoted adipose browning in high fat diet (HFD)-induced obese mice. Our results indicated that Foxc2 inhibited inflammation and promoted browning of WAT through positive regulation of leptin signal and the STAT3-PRDM16 complex. These findings identify a new potential means to prevent and treat obese caused metabolic syndrome of mammals.

  1. Targets of B-cell antigen receptor signaling: the phosphatidylinositol 3-kinase/Akt/glycogen synthase kinase-3 signaling pathway and the Rap1 GTPase.

    PubMed

    Gold, M R; Ingham, R J; McLeod, S J; Christian, S L; Scheid, M P; Duronio, V; Santos, L; Matsuuchi, L

    2000-08-01

    In this review, we discuss the role of phosphatidylinositol 3-kinase (PI3K) and Rap 1 in B-cell receptor (BCR) signaling. PI3K produces lipids that recruit pleckstrin homology domain-containing proteins to the plasma membrane. Akt is a kinase that the BCR activates in this manner. Akt phosphorylates several transcription factors as well as proteins that regulate apoptosis and protein synthesis. Akt also regulates glycogen synthase kinase-3, a kinase whose substrates include the nuclear factor of activated T cells (NF-AT)cl and beta-catenin transcriptional activators. In addition to Akt, PI3K-derived lipids also regulate the activity and localization of other targets of BCR signaling. Thus, a key event in BCR signaling is the recruitment of PI3K to the plasma membrane where its substrates are located. This is mediated by binding of the Src homology (SH) 2 domains in PI3K to phosphotyrosine-containing sequences on membrane-associated docking proteins. The docking proteins that the BCR uses to recruit PI3K include CD19, Cbl, Gab1, and perhaps Gab2. We have shown that Gab1 colocalizes PI3K with SH2 domain-containing inositol phosphatase (SHIP) and SHP2, two enzymes that regulate PI3K-dependent signaling. In contrast to PI3K, little is known about the Rap1 GTPase. We showed that the BCR activates Rap1 via phospholipase C-dependent production of diacylglycerol. Since Rap1 is thought to regulate cell adhesion and cell polarity, it may be involved in B-cell migration.

  2. Conventional Protein Kinase C-α (PKC-α) and PKC-β Negatively Regulate RIG-I Antiviral Signal Transduction

    PubMed Central

    Maharaj, Natalya P.; Wies, Effi; Stoll, Andrej

    2012-01-01

    Retinoic acid-inducible gene I (RIG-I) is a key sensor for viral RNA in the cytosol, and it initiates a signaling cascade that leads to the establishment of an interferon (IFN)-mediated antiviral state. Because of its integral role in immune signaling, RIG-I activity must be precisely controlled. Recent studies have shown that RIG-I CARD-dependent signaling function is regulated by the dynamic balance between phosphorylation and TRIM25-induced K63-linked ubiquitination. While ubiquitination of RIG-I is critical for RIG-I's ability to induce an antiviral IFN response, phosphorylation of RIG-I at S8 or T170 suppresses RIG-I signal-transducing activity under normal conditions. Here, we not only further define the roles of S8 and T170 phosphorylation for controlling RIG-I activity but also identify conventional protein kinase C-α (PKC-α) and PKC-β as important negative regulators of the RIG-I signaling pathway. Mutational analysis indicated that while the phosphorylation of S8 or T170 potently inhibits RIG-I downstream signaling, the dephosphorylation of RIG-I at both residues is necessary for optimal TRIM25 binding and ubiquitination-mediated RIG-I activation. Furthermore, exogenous expression, gene silencing, and specific inhibitor treatment demonstrated that PKC-α/β are the primary kinases responsible for RIG-I S8 and T170 phosphorylation. Coimmunoprecipitation showed that PKC-α/β interact with RIG-I under normal conditions, leading to its phosphorylation, which suppresses TRIM25 binding, RIG-I CARD ubiquitination, and thereby RIG-I-mediated IFN induction. PKC-α/β double-knockdown cells exhibited markedly decreased S8/T170 phosphorylation levels of RIG-I and resistance to infection by vesicular stomatitis virus. Thus, these findings demonstrate that PKC-α/β-induced RIG-I phosphorylation is a critical regulatory mechanism for controlling RIG-I antiviral signal transduction under normal conditions. PMID:22114345

  3. The Dynamic Performance of Flexural Ultrasonic Transducers.

    PubMed

    Feeney, Andrew; Kang, Lei; Rowlands, George; Dixon, Steve

    2018-01-18

    Flexural ultrasonic transducers are principally used as proximity sensors and for industrial metrology. Their operation relies on a piezoelectric ceramic to generate a flexing of a metallic membrane, which delivers the ultrasound signal. The performance of flexural ultrasonic transducers has been largely limited to excitation through a short voltage burst signal at a designated mechanical resonance frequency. However, a steady-state amplitude response is not generated instantaneously in a flexural ultrasonic transducer from a drive excitation signal, and differences in the drive characteristics between transmitting and receiving transducers can affect the measured response. This research investigates the dynamic performance of flexural ultrasonic transducers using acoustic microphone measurements and laser Doppler vibrometry, supported by a detailed mechanical analog model, in a process which has not before been applied to the flexural ultrasonic transducer. These techniques are employed to gain insights into the physics of their vibration behaviour, vital for the optimisation of industrial ultrasound systems.

  4. The Dynamic Performance of Flexural Ultrasonic Transducers

    PubMed Central

    Kang, Lei; Rowlands, George; Dixon, Steve

    2018-01-01

    Flexural ultrasonic transducers are principally used as proximity sensors and for industrial metrology. Their operation relies on a piezoelectric ceramic to generate a flexing of a metallic membrane, which delivers the ultrasound signal. The performance of flexural ultrasonic transducers has been largely limited to excitation through a short voltage burst signal at a designated mechanical resonance frequency. However, a steady-state amplitude response is not generated instantaneously in a flexural ultrasonic transducer from a drive excitation signal, and differences in the drive characteristics between transmitting and receiving transducers can affect the measured response. This research investigates the dynamic performance of flexural ultrasonic transducers using acoustic microphone measurements and laser Doppler vibrometry, supported by a detailed mechanical analog model, in a process which has not before been applied to the flexural ultrasonic transducer. These techniques are employed to gain insights into the physics of their vibration behaviour, vital for the optimisation of industrial ultrasound systems. PMID:29346297

  5. IL-9 exhibits elevated expression in osteonecrosis of femoral head patients and promotes cartilage degradation through activation of JAK-STAT signaling in vitro.

    PubMed

    Geng, Wei; Zhang, Wen; Ma, Jinzhu

    2018-05-15

    Osteonecrosis of the femoral head (ONFH) often causes severe symptoms in young people and limits the mobility of the hip joint. Interleukin-9 (IL-9) is a multi-functional inflammatory factor that participates in lumbar disk herniation and arthritis and has been reported in many studies. However, the correlation between IL-9 and ONFH is unclear. The present study aimed to determine the role of IL-9 in the pathogenetic mechanism of osteonecrosis. To assess IL-9 expression in ONFH and femoral neck fracture patients, cartilage tissue was examined through western blot analysis and immunohistochemistry. Human primary chondrocytes were stimulated with IL-9, and inflammation-related cytokines and cartilage matrix-degrading enzymes were assessed via real-time PCR. After being treated with IL-9, Janus kinase-signal transducers and activators of transcription (JAK-STAT) signaling were tested through western blot analysis. Our results showed a significant increase in the expression of IL-9 in ONFH patients. IL-9 raised the level of inflammation-related cytokines and cartilage matrix-degrading enzymes and enhanced the activation of JAK-STAT signaling. Furthermore, blocking the JAK-STAT signaling pathway reduced the secretion of inflammation-related cytokines and cartilage matrix-degrading enzymes and markedly alleviated the degradation of the cartilage matrix. These findings provide new insights into the role that IL-9 plays in the pathogenetic mechanism of osteonecrosis and also provide a potential treatment for ONFH. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Synthesis and self-assembly of Janus and patchy colloidal particles

    NASA Astrophysics Data System (ADS)

    Jiang, Shan

    Colloidal particles are considered classically as spherical particles with homogeneous surface chemistry. When this is so, the interactions between particles are isotropic and governed only by their separations. One can take advantage of this to simulate atoms, visualizing them one-by-one in a microscope, albeit at a larger length scale and longer time scale than for true atoms. However if the particles are not homogeneous, but Janus or patchy instead, with different surface chemistry on different hemispheres or otherwise different surface sites that are addressably controlled, the interactions between these particles depend not only on their separation, but also on their orientation. Research on Janus and patchy colloidal particles has opened a new chapter in the colloid research field, allowing us to mimic the behavior of these colloidal analogues of molecules, and in this way to ask new and exciting questions of condensed matter physics. In this dissertation, I investigated the synthesis and self-assembly of Janus and patchy colloidal particles with emphasis on Janus amphiphilic particles, which are the colloidal counterpart of surfactant molecules. Improving the scale-up capability, and also the capacity to control the geometry of Janus particles, I developed a simple and versatile method to synthesize Janus particles using an approach based on Pickering emulsions with particles adsorbed at the liquid-liquid interface. I showed that this method can be scaled up to synthesize Janus particles in large quantity. Also, the Janus balance can be predictably controlled by adding surfactant molecules during emulsification. In addition, going beyond the Janus geometry, I developed another synthetic method to fabricate trivalent patchy colloidal particles using micro-contact printing. With these synthetic methods in hand, I explored the self-assembly of Janus amphiphilic particles in aqueous solutions, while controlling systematically the salt concentration, the particle

  7. Transcriptional activation of the suppressor of cytokine signaling-3 (SOCS-3) gene via STAT3 is increased in F9 REX1 (ZFP-42) knockout teratocarcinoma stem cells relative to wild-type cells.

    PubMed

    Xu, Juliana; Sylvester, Renia; Tighe, Ann P; Chen, Siming; Gudas, Lorraine J

    2008-03-14

    Rex1 (Zfp42), first identified as a gene that is transcriptionally repressed by retinoic acid (RA), encodes a zinc finger transcription factor expressed at high levels in F9 teratocarcinoma stem cells, embryonic stem cells, and other stem cells. Loss of both alleles of Rex1 by homologous recombination alters the RA-induced differentiation of F9 cells, a model of pluripotent embryonic stem cells. We identified Suppressor of Cytokine Signaling-3 (SOCS-3) as a gene that exhibits greatly increased transcriptional activation in RA, cAMP, and theophylline (RACT)-treated F9 Rex1(-/-) cells (approximately 25-fold) as compared to wild-type (WT) cells ( approximately 2.5-fold). By promoter deletion, mutation, and transient transfection analyses, we have shown that this transcriptional increase is mediated by the STAT3 DNA-binding elements located between -99 to -60 in the SOCS-3 promoter. Overexpression of STAT3 dominant-negative mutants greatly diminishes this SOCS-3 transcriptional increase in F9 Rex1(-/-) cells. This increase in SOCS-3 transcription is associated with a four- to fivefold higher level of tyrosine-phosphorylated STAT3 in the RACT-treated F9 Rex1(-/-) cells as compared to WT. Dominant-negative Src tyrosine kinase, Jak2, and protein kinase A partially reduce the transcriptional activation of the SOCS 3 gene in RACT-treated F9 Rex1 null cells. In contrast, parathyroid hormone peptide enhances the effect of RA in F9 Rex1(-/-) cells, but not in F9 WT. Thus, Rex1, which is highly expressed in stem cells, inhibits signaling via the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway, thereby modulating the differentiation of F9 cells.

  8. Brassinosteroid regulated kinases (BRKs) that mediate brassinosteroid signal transduction and uses thereof

    DOEpatents

    Wang, Zhi-Yong; Tang, Wenqiang

    2013-09-24

    The present invention identifies a novel family of kinases regulated by brassinosteroids, referred to as BRKs (brassinosteroid regulated kinases) or BSKs (brassinosteroid signaling kinases). The present invention provides methods for modulating the response of a plant cell to a brassinosteroid using BRKs.

  9. Three-dimensional ghost imaging using acoustic transducer

    NASA Astrophysics Data System (ADS)

    Zhang, Chi; Guo, Shuxu; Guan, Jian; Cao, Junsheng; Gao, Fengli

    2016-06-01

    We propose a novel three-dimensional (3D) ghost imaging method using unfocused ultrasonic transducer, where the transducer is used as the bucket detector to collect the total photoacoustic signal intensity from spherical surfaces with different radius circling the transducer. This collected signal is a time sequence corresponding to the optic absorption information on the spherical surfaces, and the values at the same moments in all the sequences are used as the bucket signals to restore the corresponding spherical images, which are assembled as the object 3D reconstruction. Numerical experiments show this method can effectively accomplish the 3D reconstruction and by adding up each sequence on time domain as a bucket signal it can also realize two dimensional (2D) ghost imaging. The influence of the measurement times on the 3D and 2D reconstruction is analyzed with Peak Signal to Noise Ratio (PSNR) as the yardstick, and the transducer as a bucket detector is also discussed.

  10. Interferon Independent Non-Canonical STAT Activation and Virus Induced Inflammation

    PubMed Central

    Wu, Chunyan

    2018-01-01

    Interferons (IFNs) are a group of secreted proteins that play critical roles in antiviral immunity, antitumor activity, activation of cytotoxic T cells, and modulation of host immune responses. IFNs are cytokines, and bind receptors on cell surfaces to trigger signal transduction. The major signaling pathway activated by IFNs is the JAK/STAT (Janus kinase/signal transducer and activator of transcription) pathway, a complex pathway involved in both viral and host survival strategies. On the one hand, viruses have evolved strategies to escape from antiviral host defenses evoked by IFN-activated JAK/STAT signaling. On the other hand, viruses have also evolved to exploit the JAK/STAT pathway to evoke activation of certain STATs that somehow promote viral pathogenesis. In this review, recent progress in our understanding of the virus-induced IFN-independent STAT signaling and its potential roles in viral induced inflammation and pathogenesis are summarized in detail, and perspectives are provided. PMID:29662014

  11. Structural assembly of the signaling competent ERK2–RSK1 heterodimeric protein kinase complex

    PubMed Central

    Alexa, Anita; Gógl, Gergő; Glatz, Gábor; Garai, Ágnes; Zeke, András; Varga, János; Dudás, Erika; Jeszenői, Norbert; Bodor, Andrea; Hetényi, Csaba; Reményi, Attila

    2015-01-01

    Mitogen-activated protein kinases (MAPKs) bind and activate their downstream kinase substrates, MAPK-activated protein kinases (MAPKAPKs). Notably, extracellular signal regulated kinase 2 (ERK2) phosphorylates ribosomal S6 kinase 1 (RSK1), which promotes cellular growth. Here, we determined the crystal structure of an RSK1 construct in complex with its activator kinase. The structure captures the kinase–kinase complex in a precatalytic state where the activation loop of the downstream kinase (RSK1) faces the enzyme's (ERK2) catalytic site. Molecular dynamics simulation was used to show how this heterodimer could shift into a signaling-competent state. This structural analysis combined with biochemical and cellular studies on MAPK→MAPKAPK signaling showed that the interaction between the MAPK binding linear motif (residing in a disordered kinase domain extension) and the ERK2 “docking” groove plays the major role in making an encounter complex. This interaction holds kinase domains proximal as they “readjust,” whereas generic kinase domain surface contacts bring them into a catalytically competent state. PMID:25730857

  12. An enzyme logic bioprotonic transducer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Miyake, Takeo; Keene, Scott; Deng, Yingxin

    2015-01-01

    Translating ionic currents into measureable electronic signals is essential for the integration of bioelectronic devices with biological systems. We demonstrate the use of a Pd/PdH{sub x} electrode as a bioprotonic transducer that connects H{sup +} currents in solution into an electronic signal. This transducer exploits the reversible formation of PdH{sub x} in solution according to PdH↔Pd + H{sup +} + e{sup −}, and the dependence of this formation on solution pH and applied potential. We integrate the protonic transducer with glucose dehydrogenase as an enzymatic AND gate for glucose and NAD{sup +}. PdH{sub x} formation and associated electronic current monitorsmore » the output drop in pH, thus transducing a biological function into a measurable electronic output.« less

  13. p21-activated kinase signaling in breast cancer.

    PubMed

    Gururaj, Anupama E; Rayala, Suresh K; Kumar, Rakesh

    2005-01-01

    The p21-activated kinases signal through a number of cellular pathways fundamental to growth, differentiation and apoptosis. A wealth of information has accumulated at an impressive pace in the recent past, both with regard to previously identified targets for p21-activated kinases that regulate the actin cytoskeleton and cellular stress pathways and with regard to newly identified targets and their role in cancer. Emerging data also provide new clues towards a previously unappreciated link between these various cellular processes. The present review attempts to provide a quick tutorial to the reader about the evolving significance of p21-activated kinases and small GTPases in breast cancer, using information from mouse models, tissue culture studies, and human materials.

  14. Characteristics of receptor- and transducer-coupled activation of the intracellular signalling in sensory neuron revealed by atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Khalisov, M. M.; Penniyaynen, V. A.; Esikova, N. A.; Ankudinov, A. V.; Krylov, B. V.

    2017-01-01

    The mechanical properties of sensory neurons upon activation of intracellular cascade processes by comenic acid binding to a membrane opioid-like receptor (receptor-coupled), as well as a very low (endogenous) concentration of ouabain (transducer-coupled), have been investigated. Using atomic force microscopy, it is established that exposure to ouabain, in contrast to the impact of comenic acid, leads to a hardening of the neuron soma. This suggests that the receptor-coupled signal transmission to the cell genome is carried out through mechanisms that are different from the transducer-coupled signal pathways.

  15. Adiponectin inhibits leptin signalling via multiple mechanisms to exert protective effects against hepatic fibrosis.

    PubMed

    Handy, Jeffrey A; Fu, Ping P; Kumar, Pradeep; Mells, Jamie E; Sharma, Shvetank; Saxena, Neeraj K; Anania, Frank A

    2011-12-15

    Adiponectin is protective against hepatic fibrosis, whereas leptin promotes fibrosis. In HSCs (hepatic stellate cells), leptin signals via a JAK2 (Janus kinase 2)/STAT3 (signal transducer and activator of transcription 3) pathway, producing effects that enhance ECM (extracellular matrix) deposition. SOCS-3 (suppressor of cytokine signalling-3) and PTP1B (protein tyrosine phosphatase 1B) are both negative regulators of JAK/STAT signalling, and recent studies have demonstrated a role for adiponectin in regulating SOCS-3 expression. In the present study we investigate mechanisms whereby adiponectin dampens leptin signalling and prevents excess ECM production. We treated culture-activated rat HSCs with recombinant adiponectin, leptin, both or neither, and also treated adiponectin knockout (Ad-/-) and wild-type mice with leptin and/or carbon tetrachloride (CCl4) or saline. We analyse JAK2 and Ob-Rb (long form of the leptin receptor) phosphorylation, and PTP1B expression and activity. We also explore potential mechanisms through which adiponectin regulates SOCS-3-Ob-Rb association. Adiponectin inhibits leptin-stimulated JAK2 activation and Ob-Rb phosphorylation in HSCs, whereas both were increased in Ad-/- mice. Adiponectin stimulates PTP1B expression and activity in vitro, whereas PTP1B expression was lower in Ad-/-mice than in wild-type mice. Adiponectin also promotes SOCS-3-Ob-R association and blocks leptin-stimulated formation of extracellular TIMP-1 (tissue inhibitor of metalloproteinases-1)-MMP-1 (matrix metalloproteinase-1) complexes in vitro. These results suggest two novel mechanisms whereby adiponectin inhibits hepatic fibrosis: (i) by promoting binding of SOCS-3 to Ob-Rb, and (ii) by stimulating PTP1B expression and activity, thus inhibiting JAK2/STAT3 signalling at multiple points.

  16. Micro-valve using induced-charge electrokinetic motion of Janus particle.

    PubMed

    Daghighi, Yasaman; Li, Dongqing

    2011-09-07

    A new micro-valve using the electrokinetic motion of a Janus particle is introduced in this paper. A Janus particle with a conducting hemisphere and a non-conducting hemisphere is placed in a junction of several microchannels. Under an applied electric field, the induced-charge electrokinetic flow around the conducting side of the Janus particle forms vortices. The vortices push the particle moving forwards to block the entrance of a microchannel. By switching the direction of the applied electric field, the motion of the Janus particle can be changed to block different microchannels. This paper develops a theoretical model and conducts numerical simulations of the three-dimensional transient motion of the Janus particle. The results show that this Janus particle-based micro-valve is feasible for switching and controlling the flow rate in a microfluidic chip. This method is simple in comparison with other types of micro-valve methods. It is easy for fabrication, for operation control, and has a fast response time. To better understand the micro-valve functions, comparisons with a non-conducting particle and a fully conducting particle were made. Results proved that only a Janus particle can fulfill the requirements of such a micro-valve.

  17. Jak2 FERM Domain Interaction with the Erythropoietin Receptor Regulates Jak2 Kinase Activity▿

    PubMed Central

    Funakoshi-Tago, Megumi; Pelletier, Stéphane; Moritake, Hiroshi; Parganas, Evan; Ihle, James N.

    2008-01-01

    Janus kinases are essential for signal transduction by a variety of cytokine receptors and when inappropriately activated can cause hematopoietic disorders and oncogenesis. Consequently, it can be predicted that the interaction of the kinases with receptors and the events required for activation are highly controlled. In a screen to identify phosphorylation events regulating Jak2 activity in EpoR signaling, we identified a mutant (Jak2-Y613E) which has the property of being constitutively activated, as well as an inactivating mutation (Y766E). Although no evidence was obtained to indicate that either site is phosphorylated in signaling, the consequences of the Y613E mutation are similar to those observed with recently described activating mutations in Jak2 (Jak2-V617F and Jak2-L611S). However, unlike the V617F or L611S mutant, the Y613E mutant requires the presence of the receptor but not Epo stimulation for activation and downstream signaling. The properties of the Jak2-Y613E mutant suggest that under normal conditions, Jak2 that is not associated with a receptor is locked into an inactive state and receptor binding through the FERM domain relieves steric constraints, allowing the potential to be activated with receptor engagement. PMID:18160720

  18. System for forming janus particles

    DOEpatents

    Hong, Liang [Midland, MI; Jiang, Shan [Champaign, IL; Granick, Steve [Champaign, IL

    2011-01-25

    The invention is a method of forming Janus particles, that includes forming an emulsion that contains initial particles, a first liquid, and a second liquid; solidifying the first liquid to form a solid that contains at least a portion of the initial particles on a surface of the solid; and treating the exposed particle sides with a first surface modifying agent, to form the Janus particles. Each of the initial particles on the surface has an exposed particle side and a blocked particle side.

  19. Calcium and signal transduction in plants

    NASA Technical Reports Server (NTRS)

    Poovaiah, B. W.; Reddy, A. S.

    1993-01-01

    Environmental and hormonal signals control diverse physiological processes in plants. The mechanisms by which plant cells perceive and transduce these signals are poorly understood. Understanding biochemical and molecular events involved in signal transduction pathways has become one of the most active areas of plant research. Research during the last 15 years has established that Ca2+ acts as a messenger in transducing external signals. The evidence in support of Ca2+ as a messenger is unequivocal and fulfills all the requirements of a messenger. The role of Ca2+ becomes even more important because it is the only messenger known so far in plants. Since our last review on the Ca2+ messenger system in 1987, there has been tremendous progress in elucidating various aspects of Ca(2+) -signaling pathways in plants. These include demonstration of signal-induced changes in cytosolic Ca2+, calmodulin and calmodulin-like proteins, identification of different Ca2+ channels, characterization of Ca(2+) -dependent protein kinases (CDPKs) both at the biochemical and molecular levels, evidence for the presence of calmodulin-dependent protein kinases, and increased evidence in support of the role of inositol phospholipids in the Ca(2+) -signaling system. Despite the progress in Ca2+ research in plants, it is still in its infancy and much more needs to be done to understand the precise mechanisms by which Ca2+ regulates a wide variety of physiological processes. The purpose of this review is to summarize some of these recent developments in Ca2+ research as it relates to signal transduction in plants.

  20. Leptin promotes human endometriotic cell migration and invasion by up-regulating MMP-2 through the JAK2/STAT3 signaling pathway.

    PubMed

    Ahn, Ji-Hye; Choi, Youn Seok; Choi, Jung-Hye

    2015-10-01

    Despite evidence that leptin may play a role in the pathogenesis of endometriosis, the specific function of leptin in the migration and invasion of endometriotic cells is not well characterized. In this study, we investigated the effect of leptin on the migration, invasion and matrix metalloproteinase (MMP) expression levels of human endometriotic cells. We found that leptin stimulated the migration and invasion of endometriotic cells (11Z, 12Z and 22B) in a dose-dependent manner. Leptin receptor (ObR) siRNA significantly inhibited the migration and invasion induced by leptin in 11Z and 12Z cells. Leptin-induced migration and invasion were significantly attenuated by pretreatment with SB-3CT, a specific gelatinase (MMP-2 and MMP-9) inhibitor. In addition, leptin-induced increases in the mRNA and protein expression and enzyme activity of MMP-2 in 11Z and 12Z cells. Selectively inhibiting MMP-2 using siRNA and an inhibitor (GM6003), impaired the ability of leptin to stimulate the migration and invasion of endometriotic cells, suggesting that MMP-2 plays an essential role in leptin-induced migration and invasion. Janus Kinase 2/Signal Transducer and Activator of Transcription 3 (JAK2/STAT3) inhibitor (AG490) significantly inhibited the migration, invasion and MMP-2 expression induced by leptin in endometriotic cells. Furthermore, the Extracellular signal-Regulated Kinase inhibitor PD98059 neutralized the migration and invasion promoting effects of leptin. Taken together, these results suggest that leptin may contribute to the migration and invasion abilities of endometriotic cells via the up-regulation of MMP-2 through an ObR-dependent JAK2/STAT3 signaling pathway. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. ERROR COMPENSATOR FOR A POSITION TRANSDUCER

    DOEpatents

    Fowler, A.H.

    1962-06-12

    A device is designed for eliminating the effect of leadscrew errors in positioning machines in which linear motion of a slide is effected from rotary motion of a leadscrew. This is accomplished by providing a corrector cam mounted on the slide, a cam follower, and a transducer housing rotatable by the follower to compensate for all the reproducible errors in the transducer signal which can be related to the slide position. The transducer has an inner part which is movable with respect to the transducer housing. The transducer inner part is coupled to the means for rotating the leadscrew such that relative movement between this part and its housing will provide an output signal proportional to the position of the slide. The corrector cam and its follower perform the compensation by changing the angular position of the transducer housing by an amount that is a function of the slide position and the error at that position. (AEC)

  2. Lipid membrane-assisted condensation and assembly of amphiphilic Janus particles

    DOE PAGES

    Chambers, Mariah; Mallory, Stewart Anthony; Malone, Heather; ...

    2016-01-01

    Amphiphilic Janus particles self-assemble into complex metastructures, but little is known about how their assembly might be modified by weak interactions with a nearby biological membrane surface. Here, we report an integrated experimental and molecular dynamics simulation study to investigate the self-assembly of amphiphilic Janus particles on a lipid membrane. We created an experimental system in which Janus particles are allowed to self-assemble in the same medium where zwitterionic lipids form giant unilamellar vesicles (GUVs). Janus particles spontaneously concentrated on the inner leaflet of the GUVs. They exhibited biased orientation and heterogeneous rotational dynamics as revealed by single particle rotationalmore » tracking. The combined experimental and simulation results show that Janus particles concentrate on the lipid membranes due to weak particle–lipid attraction, whereas the biased orientation of particles is driven predominantly by inter-particle interactions. Furthermore, this study demonstrates the potential of using lipid membranes to influence the self-assembly of Janus particles.« less

  3. Microbial Degradation of Cellular Kinases Impairs Innate Immune Signaling and Paracrine TNFα Responses

    PubMed Central

    Barth, Kenneth; Genco, Caroline Attardo

    2016-01-01

    The NFκB and MAPK signaling pathways are critical components of innate immunity that orchestrate appropriate immune responses to control and eradicate pathogens. Their activation results in the induction of proinflammatory mediators, such as TNFα a potent bioactive molecule commonly secreted by recruited inflammatory cells, allowing for paracrine signaling at the site of an infection. In this study we identified a novel mechanism by which the opportunistic pathogen Porphyromonas gingivalis dampens innate immune responses by disruption of kinase signaling and degradation of inflammatory mediators. The intracellular immune kinases RIPK1, TAK1, and AKT were selectively degraded by the P. gingivalis lysine-specific gingipain (Kgp) in human endothelial cells, which correlated with dysregulated innate immune signaling. Kgp was also observed to attenuate endothelial responsiveness to TNFα, resulting in a reduction in signal flux through AKT, ERK and NFκB pathways, as well as a decrease in downstream proinflammatory mRNA induction of cytokines, chemokines and adhesion molecules. A deficiency in Kgp activity negated decreases to host cell kinase protein levels and responsiveness to TNFα. Given the essential role of kinase signaling in immune responses, these findings highlight a unique mechanism of pathogen-induced immune dysregulation through inhibition of cell activation, paracrine signaling, and dampened cellular proinflammatory responses. PMID:27698456

  4. Trichostatin A, a histone deacetylase inhibitor, suppresses JAK2/STAT3 signaling via inducing the promoter-associated histone acetylation of SOCS1 and SOCS3 in human colorectal cancer cells.

    PubMed

    Xiong, Hua; Du, Wan; Zhang, Yan-Jie; Hong, Jie; Su, Wen-Yu; Tang, Jie-Ting; Wang, Ying-Chao; Lu, Rong; Fang, Jing-Yuan

    2012-02-01

    Aberrant janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling is involved in the oncogenesis of several cancers. Suppressors of cytokine signaling (SOCS) genes and SH2-containing protein tyrosine phosphatase 1 (SHP1) proteins, which are negative regulators of JAK/STAT signaling, have been reported to have tumor suppressor functions. However, in colorectal cancer (CRC) cells, the mechanisms that regulate SOCS and SHP1 genes, and the cause of abnormalities in the JAK/STAT signaling pathway, remain largely unknown. The present study shows that trichostatin A (TSA), a histone deacetylase (HDAC) inhibitor, leads to the hyperacetylation of histones associated with the SOCS1 and SOCS3 promoters, but not the SHP1 promoter in CRC cells. This indicates that histone modifications are involved in the regulation of SOCS1 and SOCS3. Moreover, upregulation of SOCS1 and SOCS3 expression was achieved using TSA, which also significantly downregulated JAK2/STAT3 signaling in CRC cells. We also demonstrate that TSA suppresses the growth of CRC cells, and induces G1 cell cycle arrest and apoptosis through the regulation of downstream targets of JAK2/STAT3 signaling, including Bcl-2, survivin and p16(ink4a) . Therefore, our data demonstrate that TSA may induce SOCS1 and SOCS3 expression by inducing histone modifications and consequently inhibits JAK2/STAT3 signaling in CRC cells. These results also establish a mechanistic link between the inhibition of JAK2/STAT3 signaling and the anticancer action of TSA in CRC cells. Copyright © 2011 Wiley Periodicals, Inc.

  5. AMP-activated protein kinase is involved in neural stem cell growth suppression and cell cycle arrest by 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside and glucose deprivation by down-regulating phospho-retinoblastoma protein and cyclin D.

    PubMed

    Zang, Yi; Yu, Li-Fang; Nan, Fa-Jun; Feng, Lin-Yin; Li, Jia

    2009-03-06

    The fate of neural stem cells (NSCs), including their proliferation, differentiation, survival, and death, is regulated by multiple intrinsic signals and the extrinsic environment. We had previously reported that 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR) directly induces astroglial differentiation of NSCs by activation of the Janus kinase (JAK)/Signal transducer and activator of transcription 3 (STAT3) pathway independently of AMP-activated protein kinase (AMPK). Here, we reported the observation that AICAR inhibited NSC proliferation and its underlying mechanism. Analysis of caspase activity and cell cycle showed that AICAR induced G1/G0 cell cycle arrest in NSCs, associated with decreased levels of poly(ADP-ribose) polymerase, phospho-retinoblastoma protein (Rb), and cyclin D but did not cause apoptosis. Iodotubericidin and Compound C, inhibitors of adenosine kinase and AMPK, respectively, or overexpression of a dominant-negative mutant of AMPK, but not JAK inhibitor, were able to reverse the anti-proliferative effect of AICAR. Glucose deprivation also activated the AMPK pathway, induced G0/G1 arrest, and suppressed the proliferation of NSCs, an effect associated with decreased levels of phospho-Rb and cyclin D protein. Furthermore, Compound C and overexpression of dominant-negative AMPK in C17.2 NSCs could block the glucose deprivation-mediated down-regulation of cyclin D and partially reverse the suppression of proliferation. These results suggest that AICAR and glucose deprivation might induce G1/G0 cell cycle arrest and suppress proliferation of NSCs via phospho-Rb and cyclin D down-regulation. AMPK, but not JAK/STAT3, activation is key for this inhibitory effect and may play an important role in the responses of NSCs to metabolic stresses such as glucose deprivation.

  6. Cross-talk between KLF4 and STAT3 regulates axon regeneration

    NASA Astrophysics Data System (ADS)

    Qin, Song; Zou, Yuhua; Zhang, Chun-Li

    2013-10-01

    Cytokine-induced activation of signal transducer and activator of transcription 3 (STAT3) promotes the regrowth of damaged axons in the adult central nervous system (CNS). Here we show that KLF4 physically interacts with STAT3 upon cytokine-induced phosphorylation of tyrosine 705 (Y705) on STAT3. This interaction suppresses STAT3-dependent gene expression by blocking its DNA-binding activity. The deletion of KLF4 in vivo induces axon regeneration of adult retinal ganglion cells (RGCs) via Janus kinase (JAK)-STAT3 signalling. This regeneration can be greatly enhanced by exogenous cytokine treatment, or removal of an endogenous JAK-STAT3 pathway inhibitor called suppressor of cytokine signalling 3 (SOCS3). These findings reveal an unexpected cross-talk between KLF4 and activated STAT3 in the regulation of axon regeneration that might have therapeutic implications in promoting repair of injured adult CNS.

  7. Ultrasound transducer positioning aid for fetal heart rate monitoring.

    PubMed

    Hamelmann, Paul; Kolen, Alex; Schmitt, Lars; Vullings, Rik; van Assen, Hans; Mischi, Massimo; Demi, Libertario; van Laar, Judith; Bergmans, Jan

    2016-08-01

    Fetal heart rate (fHR) monitoring is usually performed by Doppler ultrasound (US) techniques. For reliable fHR measurements it is required that the fetal heart is located within the US beam. In clinical practice, clinicians palpate the maternal abdomen to identify the fetal presentation and then the US transducer is fixated on the maternal abdomen where the best fHR signal can be obtained. Finding the optimal transducer position is done by listening to the strength of the Doppler audio output and relying on a signal quality indicator of the cardiotocographic (CTG) measurement system. Due to displacement of the US transducer or displacement of the fetal heart out of the US beam, the fHR signal may be lost. Therefore, it is often necessary that the obstetrician repeats the tedious procedure of US transducer positioning to avoid long periods of fHR signal loss. An intuitive US transducer positioning aid would be highly desirable to increase the work flow for the clinical staff. In this paper, the possibility to determine the fetal heart location with respect to the transducer by exploiting the received signal power in the transducer elements is shown. A commercially available US transducer used for fHR monitoring is connected to an US open platform, which allows individual driving of the elements and raw US data acquisition. Based on the power of the received Doppler signals in the transducer elements, the fetal heart location can be estimated. A beating fetal heart setup was designed and realized for validation. The experimental results show the feasibility of estimating the fetal heart location with the proposed method. This can be used to support clinicians in finding the optimal transducer position for fHR monitoring more easily.

  8. Secoisolariciresinol diglucoside prevents the oxidative stress-induced apoptosis of myocardial cells through activation of the JAK2/STAT3 signaling pathway.

    PubMed

    Huang, Guiqiong; Huang, Xiaofang; Liu, Min; Hua, Yue; Deng, Bo; Jin, Wen; Yan, Wen; Tan, Zhangbin; Wu, Yifen; Liu, Bin; Zhou, Yingchun

    2018-06-01

    Myocardial cell apoptosis mediated by oxidative stress has previously been identified as a key process in ischemic heart disease. Secoisolariciresinol diglucoside (SDG), a polyphenolic plant lignan primarily found in flaxseed, has been demonstrated to effectively protect myocardial cells from apoptosis. In the present study, the role of the Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) was investigated in mediating the protective effect of SDG. Findings of the present study revealed that treatment with H2O2 reduced cell viability and induced apoptosis in H9C2 rat cardiomyocytes. However, SDG was able to reduce the effect of H2O2 in a dose‑dependent manner. H2O2 reduced the expression level of phosphorylated STAT3 and inhibited the levels of B‑cell lymphoma‑extra‑large and induced myeloid leukemia cell differentiation protein, which are the STAT3 target genes. Conversely, SDG rescued phosphorylation of STAT3 and increased the levels of STAT3 target genes. Treatment with SDG alone led to a dose‑dependent increased phosphorylation of JAK2 and STAT3, without activating Src. Furthermore, the anti‑apoptotic effects of SDG were partially abolished by a JAK2/STAT3 inhibitor. In addition, molecular docking revealed that SDG may bind to the protein kinase domain of JAK2, at a binding energy of ‑8.258 kcal/mol. Molecular dynamics simulations revealed that JAK2‑SDG binding was stable. In conclusion, activation of the JAK2/STAT3 signaling pathway contributed to the anti‑apoptotic activity of SDG, which may be a potential JAK2 activator.

  9. Gravitaxis in Spherical Janus Swimming Devices

    PubMed Central

    2013-01-01

    In this work, we show that the asymmetrical distribution of mass at the surface of catalytic Janus swimmers results in the devices preferentially propelling themselves upward in a gravitational field. We demonstrate the existence of this gravitaxis phenomenon by observing the trajectories of fueled Janus swimmers, which generate thrust along a vector pointing away from their metallically coated half. We report that as the size of the spherical swimmer increases, the propulsive trajectories are no longer isotropic with respect to gravity, and they start to show a pronounced tendency to move in an upward direction. We suggest that this effect is due to the platinum caps asymmetric mass exerting an increasing influence on the azimuthal angle of the Janus sphere with size, biasing its orientation toward a configuration where the heavier propulsion generating surface faces down. This argument is supported by the good agreement we find between the experimentally observed azimuthal angle distribution for the Janus swimmers and predictions made by simple Boltzmann statistics. This gravitaxis phenomenon provides a mechanism to autonomously control and direct the motion of catalytic swimming devices and so enable a route to make autonomous transport devices and develop new separation, sensing, and controlled release applications. PMID:24134682

  10. Cellular context–mediated Akt dynamics regulates MAP kinase signaling thresholds during angiogenesis

    PubMed Central

    Hellesøy, Monica; Lorens, James B.

    2015-01-01

    The formation of new blood vessels by sprouting angiogenesis is tightly regulated by contextual cues that affect angiogeneic growth factor signaling. Both constitutive activation and loss of Akt kinase activity in endothelial cells impair angiogenesis, suggesting that Akt dynamics mediates contextual microenvironmental regulation. We explored the temporal regulation of Akt in endothelial cells during formation of capillary-like networks induced by cell–cell contact with vascular smooth muscle cells (vSMCs) and vSMC-associated VEGF. Expression of constitutively active Akt1 strongly inhibited network formation, whereas hemiphosphorylated Akt1 epi-alleles with reduced kinase activity had an intermediate inhibitory effect. Conversely, inhibition of Akt signaling did not affect endothelial cell migration or morphogenesis in vSMC cocultures that generate capillary-like structures. We found that endothelial Akt activity is transiently blocked by proteasomal degradation in the presence of SMCs during the initial phase of capillary-like structure formation. Suppressed Akt activity corresponded to the increased endothelial MAP kinase signaling that was required for angiogenic endothelial morphogenesis. These results reveal a regulatory principle by which cellular context regulates Akt protein dynamics, which determines MAP kinase signaling thresholds necessary drive a morphogenetic program during angiogenesis. PMID:26023089

  11. Suppressor of cytokine signaling 1 interacts with oncogenic lymphocyte-specific protein tyrosine kinase.

    PubMed

    Venkitachalam, Srividya; Chueh, Fu-Yu; Leong, King-Fu; Pabich, Samantha; Yu, Chao-Lan

    2011-03-01

    Lymphocyte-specific protein tyrosine kinase (Lck) plays a key role in T cell signal transduction and is tightly regulated by phosphorylation and dephosphorylation. Lck can function as an oncoprotein when overexpressed or constantly activated by mutations. Our previous studies showed that Lck-induced cellular transformation could be suppressed by enforced expression of suppressor of cytokine signaling 1 (SOCS1), a SOCS family member involved in the negative feedback control of cytokine signaling. We observed attenuated Lck kinase activity in SOCS1-expressing cells, suggesting an important role of SOCS in regulating Lck functions. It remains largely unknown whether and how SOCS proteins interact with the oncogenic Lck kinase. Here, we report that among four SOCS family proteins, SOCS1, SOCS2, SOCS3 and CIS (cytokine-inducible SH2 domain containing protein), SOCS1 has the highest affinity in binding to the oncogenic Lck kinase. We identified the positive regulatory phosphotyrosine 394 residue in the kinase domain as the key interacting determinant in Lck. Additionally, the Lck kinase domain alone is sufficient to bind SOCS1. While the SH2 domain in SOCS1 is important in its association with the oncogenic Lck kinase, other functional domains may also contribute to overall binding affinity. These findings provide important mechanistic insights into the role of SOCS proteins as tumor suppressors in cells transformed by oncogenic protein tyrosine kinases.

  12. Suppressor of cytokine signaling 1 interacts with oncogenic lymphocyte-specific protein tyrosine kinase

    PubMed Central

    VENKITACHALAM, SRIVIDYA; CHUEH, FU-YU; LEONG, KING-FU; PABICH, SAMANTHA; YU, CHAO-LAN

    2011-01-01

    Lymphocyte-specific protein tyrosine kinase (Lck) plays a key role in T cell signal transduction and is tightly regulated by phosphorylation and dephosphorylation. Lck can function as an oncoprotein when overexpressed or constantly activated by mutations. Our previous studies showed that Lck-induced cellular transformation could be suppressed by enforced expression of suppressor of cytokine signaling 1 (SOCS1), a SOCS family member involved in the negative feedback control of cytokine signaling. We observed attenuated Lck kinase activity in SOCS1-expressing cells, suggesting an important role of SOCS in regulating Lck functions. It remains largely unknown whether and how SOCS proteins interact with the oncogenic Lck kinase. Here we report that, among four SOCS family proteins, SOCS1, SOCS2, SOCS3 and CIS (cytokine–inducible SH2 domain containing protein), SOCS1 has the highest affinity in binding to the oncogenic Lck kinase. We identify the positive regulatory phospho-tyrosine 394 residue in the kinase domain as the key interacting determinant in Lck. Additionally, the Lck kinase domain alone is sufficient to bind SOCS1. While the SH2 domain in SOCS1 is important in its association with the oncogenic Lck kinase, other functional domains may also contribute to overall binding affinity. These findings provide important mechanistic insights into the role of SOCS proteins as tumor suppressors in cells transformed by oncogenic protein tyrosine kinases. PMID:21234523

  13. Intersecting Roles of Protein Tyrosine Kinase and Calcium Signaling During Fertilization

    PubMed Central

    Kinsey, William H.

    2012-01-01

    The oocyte is a highly specialized cell that must respond to fertilization with a preprogrammed series of signal transduction events that establish a block to polyspermy, trigger resumption of the cell cycle and execution of a developmental program. The fertilization-induced calcium transient is a key signal that initiates the process of oocyte activation and studies over the last several years have examined the signaling pathways that act upstream and downstream of this calcium transient. Protein tyrosine kinase signaling was found to be an important component of the upstream pathways that stimulated calcium release at fertilization in oocytes from animals that fertilize externally, but a similar pathway has not been found in mammals which fertilize internally. The following review will examine the diversity of signaling in oocytes from marine invertebrates, amphibians, fish and mammals in an attempt to understand the basis for the observed differences. In addition to the pathways upstream of the fertilization-induced calcium transient, recent studies are beginning to unravel the role of protein tyrosine kinase signaling downstream of the calcium transient. The PYK2 kinase was found to respond to fertilization in the zebrafish system and seems to represent a novel component of the response of the oocyte to fertilization. The potential impact of impaired PTK signaling in oocyte quality will also be discussed. PMID:23201334

  14. Signaling of the ITK (interleukin 2-inducible T cell kinase)-SYK (spleen tyrosine kinase) fusion kinase is dependent on adapter SLP-76 and on the adapter function of the kinases SYK and ZAP70.

    PubMed

    Hussain, Alamdar; Mohammad, Dara K; Gustafsson, Manuela O; Uslu, Merve; Hamasy, Abdulrahman; Nore, Beston F; Mohamed, Abdalla J; Smith, C I Edvard

    2013-03-08

    The inducible T cell kinase-spleen tyrosine kinase (ITK-SYK) oncogene consists of the Tec homology-pleckstrin homology domain of ITK and the kinase domain of SYK, and it is believed to be the cause of peripheral T cell lymphoma. We and others have recently demonstrated that this fusion protein is constitutively tyrosine-phosphorylated and is transforming both in vitro and in vivo. To gain a deeper insight into the molecular mechanism(s) underlying its activation and signaling, we mutated a total of eight tyrosines located in the SYK portion of the chimera into either phenylalanine or to the negatively charged glutamic acid. Although mutations in the interdomain-B region affected ITK-SYK kinase activity, they only modestly altered downstream signaling events. In contrast, mutations that were introduced in the kinase domain triggered severe impairment of downstream signaling. Moreover, we show here that SLP-76 is critical for ITK-SYK activation and is particularly required for the ITK-SYK-dependent phosphorylation of SYK activation loop tyrosines. In Jurkat cell lines, we demonstrate that expression of ITK-SYK fusion requires an intact SLP-76 function and significantly induces IL-2 secretion and CD69 expression. Furthermore, the SLP-76-mediated induction of IL-2 and CD69 could be further enhanced by SYK or ZAP-70, but it was independent of their kinase activity. Notably, ITK-SYK expression in SYF cells phosphorylates SLP-76 in the absence of SRC family kinases. Altogether, our data suggest that ITK-SYK exists in the active conformation state and is therefore capable of signaling without SRC family kinases or stimulation of the T cell receptor.

  15. Signaling of the ITK (Interleukin 2-inducible T Cell Kinase)-SYK (Spleen Tyrosine Kinase) Fusion Kinase Is Dependent on Adapter SLP-76 and on the Adapter Function of the Kinases SYK and ZAP70*

    PubMed Central

    Hussain, Alamdar; Mohammad, Dara K.; Gustafsson, Manuela O.; Uslu, Merve; Hamasy, Abdulrahman; Nore, Beston F.; Mohamed, Abdalla J.; Smith, C. I. Edvard

    2013-01-01

    The inducible T cell kinase-spleen tyrosine kinase (ITK-SYK) oncogene consists of the Tec homology-pleckstrin homology domain of ITK and the kinase domain of SYK, and it is believed to be the cause of peripheral T cell lymphoma. We and others have recently demonstrated that this fusion protein is constitutively tyrosine-phosphorylated and is transforming both in vitro and in vivo. To gain a deeper insight into the molecular mechanism(s) underlying its activation and signaling, we mutated a total of eight tyrosines located in the SYK portion of the chimera into either phenylalanine or to the negatively charged glutamic acid. Although mutations in the interdomain-B region affected ITK-SYK kinase activity, they only modestly altered downstream signaling events. In contrast, mutations that were introduced in the kinase domain triggered severe impairment of downstream signaling. Moreover, we show here that SLP-76 is critical for ITK-SYK activation and is particularly required for the ITK-SYK-dependent phosphorylation of SYK activation loop tyrosines. In Jurkat cell lines, we demonstrate that expression of ITK-SYK fusion requires an intact SLP-76 function and significantly induces IL-2 secretion and CD69 expression. Furthermore, the SLP-76-mediated induction of IL-2 and CD69 could be further enhanced by SYK or ZAP-70, but it was independent of their kinase activity. Notably, ITK-SYK expression in SYF cells phosphorylates SLP-76 in the absence of SRC family kinases. Altogether, our data suggest that ITK-SYK exists in the active conformation state and is therefore capable of signaling without SRC family kinases or stimulation of the T cell receptor. PMID:23293025

  16. The protective effect of juglanin on fructose-induced hepatitis by inhibiting inflammation and apoptosis through TLR4 and JAK2/STAT3 signaling pathways in fructose-fed rats.

    PubMed

    Zhou, Guang-Yao; Yi, Yong-Xiang; Jin, Ling-Xiang; Lin, Wei; Fang, Pei-Pei; Lin, Xiu-Zheng; Zheng, Yi; Pan, Chen-Wei

    2016-07-01

    High fructose-feeding is an essential causative factor leading to the development and progression of hepatitis associated with high levels of endotoxin (LPS). Juglanin, as a natural compound extracted from the crude Polygonum aviculare, displayed inhibitory activity against inflammation response and cancer growth. However, researches about its role on anti-inflammation and apoptosis are far from available. Here, it is the first time that juglanin was administrated to investigate whether it inhibits fructose-feeding-induced hepatitis in rats and to elucidate the possible mechanism by which juglanin might recover it. Fructose-feeding rats were orally administrated with juglanin of 5, 10 and 20mg/kg for 6 weeks, respectively. Juglanin exerted prevention of fructose-feeding-stimulated increased LPS levels, accelerated alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) and up-regulated inflammatory cytokines expression in serum, mainly including tumor necrosis factor-alpha (TNF-a), Interleukin 1beta (IL-1β), Interleukin 6 (IL-6) and Interleukin 18 (IL-18). Meanwhile, toll-like receptor 4 (TLR4)-modulated mitogen-activated protein kinase (MAPK)/nuclear factor kappa B (NF-κB) and apoptosis-related Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway are involved in the progression of hepatic injury and inflammation. And juglanin was found to suppress fructose-feeding-induced activation of these signaling pathways compared with the model group administrated only with fructose. These results indicate that juglanin represses inflammatory response and apoptosis via TLR4-regulated MAPK/NF-κB and JAK2/STAT3 signaling pathway respectively in rats with hepatitis induced by LPS for fructose-feeding. Treatment of juglanin might be an effective therapeutic strategy for preventing hepatitis. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  17. Signaling through protein kinases and transcriptional regulators in Candida albicans.

    PubMed

    Dhillon, Navneet K; Sharma, Sadhna; Khuller, G K

    2003-01-01

    The human fungal pathogen Candida albicans switches from a budding yeast form to a polarized hyphal form in response to various external signals. This morphogenetic switching has been implicated in the development of pathogenicity. Several signaling pathways that regulate morphogenesis have been identified, including various transcription factors that either activate or repress hypha-specific genes. Two well-characterized pathways include the MAP kinase cascade and cAMP-dependent protein kinase pathway that regulate the transcription factors Cph1p and Efg1p, respectively. cAMP also appears to interplay with other second messengers: Ca2+, inositol tri-phosphates in regulating yeast-hyphal transition. Other, less-characterized pathways include two component histidine kinases, cyclin-dependent kinase pathway, and condition specific pathways such as pH and embedded growth conditions. Nrg1 and Rfg1 function as transcriptional repressors of hyphal genes via recruitment of Tup1 co-repressor complex. Different upstream signals converge into a common downstream output during hyphal switch. The levels of expression of several genes have been shown to be associated with hyphal morphogenesis rather than with a specific hypha-inducing condition. Hyphal development is also linked to the expression of a range of other virulence factors. This review explains the relative contribution of multiple pathways that could be used by Candida albican cells to sense subtle differences in the growth conditions of its native host environment.

  18. Leptin induces the apoptosis of chondrocytes in an in vitro model of osteoarthritis via the JAK2‑STAT3 signaling pathway.

    PubMed

    Zhang, Zi Ming; Shen, Chao; Li, Hai; Fan, Qing; Ding, Jing; Jin, Fang Chun; Sha, Lin

    2016-04-01

    Emerging data has suggested a high prevalence of osteoarthritis (OA) among obese people. As an important adipokine secreted by white adipose tissue, leptin may be a key mediator in the progression of OA. Leptin exerts a catabolic effect on OA cartilage by increasing the production of metalloproteinase (MMP) enzymes, and contributes to apoptosis in chondrocytes. The current study aimed to explore the role of leptin on the apoptosis of chondrocytes in OA, and its underlying mechanisms. In the in vitro model of OA used in the present study, administration of exogenous leptin induced the generation of reactive oxygen species (ROS) and apoptosis in chondrocytes. It has been demonstrated that leptin is associated with the pathogenesis of OA via the Janus kinase 2 (JAK2)‑signal transducer and activator of transcription 3 (STAT3) signaling pathway, and data gathered in the present study demonstrated that suppression of this signaling pathway using a JAK2 inhibitor, AG490, significantly ameliorated leptin‑induced apoptosis in damaged chondrocytes in vitro, and reduced the generation of ROS. Furthermore, the protein expression levels of MMP‑13 and B‑cell lymphoma 2‑associated X protein were downregulated in the AG490‑treated group. The results of the present study may provide insight into the underlying molecular mechanism by which leptin induces apoptosis in chondrocytes. These findings indicated the importance of leptin as a therapeutic target for the treatment of OA in the overweight population.

  19. Wideband Single-Crystal Transducer for Bone Characterization

    NASA Technical Reports Server (NTRS)

    Liang, Yu; Snook, Kevin

    2012-01-01

    The microgravity conditions of space travel result in unique physiological demands on the human body. In particular, the absence of the continual mechanical stresses on the skeletal system that are present on Earth cause the bones to decalcify. Trabecular structure decreases in thickness and increases in spacing, resulting in decreased bone strength and increased risk of injury. Thus, monitoring bone health is a high priority for long-term space travel. A single probe covering all frequency bands of interest would be ideal for such measurements, and this would also minimize storage space and eliminate the complexity of integrating multiple probes. This invention is an ultrasound transducer for the structural characterization of bone. Such characterization measures features of reflected and transmitted ultrasound signals, and correlates these signals with bone structure metrics such as bone mineral density, trabecular spacing, and thickness, etc. The techniques used to determine these various metrics require measurements over a broad range of ultrasound frequencies, and therefore, complete characterization requires the use of several narrowband transducers. This is a single transducer capable of making these measurements in all the required frequency bands. The device achieves this capability through a unique combination of a broadband piezoelectric material; a design incorporating multiple resonator sizes with distinct, overlapping frequency spectra; and a micromachining process for producing the multiple-resonator pattern with common electrode surfaces between the resonators. This device consists of a pattern of resonator bars with common electrodes that is wrapped around a central mandrel such that the radiating faces of the resonators are coplanar and can be simultaneously applied to the sample to be measured. The device operates as both a source and receiver of acoustic energy. It is operated by connection to an electronic system capable of both providing an

  20. Chronic active Epstein–Barr virus infection as the initial symptom in a Janus kinase 3 deficiency child

    PubMed Central

    Zhong, Linqing; Wang, Wei; Ma, Mingsheng; Gou, Lijuan; Tang, Xiaoyan; Song, Hongmei

    2017-01-01

    Abstract Rationale: With the progress of sequencing technology, an increasing number of atypical primary immunodeficiency (PID) patients have been discovered, including Janus kinase 3 (JAK3) gene deficiency. Patient concerns: We report a patient who presented with chronic active Epstein–Barr virus (CAEBV) infection but responded poorly to treatment with ganciclovir. Diagnoses: Next-generation sequencing (NGS) was performed, including all known PID genes, after which Sanger sequencing was performed to verify the results. Genetic analysis revealed that our patient had 2 novel compound heterozygous mutations of JAK3, a gene previously reported to cause a rare form of autosomal recessive severe combined immunodeficiency with recurrent infections. The p.H27Q mutation came from his father, while p. R222H from his mother. Thus, his diagnosis was corrected for JAK3-deficiency PID and CAEBV. Interventions: Maintenance treatment of subcutaneous injection of recombinant human interferon α-2a was given to our patient with 2 MU, 3 times a week. Outcomes: Interferon alpha was applied and the EBV infection was gradually controlled and his symptoms ameliorated remarkably. Our patient is in good health now and did not have relapses. Lessons: The diagnoses of PID should be taken into consideration when CAEBV patients respond poorly to conventional treatments. Good results of our patient indicate that interferon α-2a may be an alternative treatment for those who are unwilling to accept hematopoietic stem cell transplantation (HSCT) like our patient. Literature review identified 59 additional cases of JAK3 deficiency with various infections. PMID:29049190

  1. Janus Kinase 2 Polymorphisms Are Associated with Risk in Patients with Gastric Cancer in a Chinese Population

    PubMed Central

    Guo, Renhua; Zhang, Zhihong; Xu, Hao; Yang, Chao; Zhu, Yi

    2013-01-01

    Aim To evaluate the impact of the Janus kinase 2 single nucleotide polymorphisms (SNPs) on gastric cancer risk. Methods In this hospital-based, case–control study, the genotypes were identified by polymerase chain reaction–restriction fragment length polymorphism protocols in 661 individuals (359 gastric cancer patients and 302 age and sex matched cancer-free controls). Results Both the frequency of A allele in rs2230724 and G allele in rs1887427 were more frequent in patients with gastric cancer (P = 0.013 and 0.001, respectively). Compared with the common genotype, subjects with the (AG+AA) genotypes of rs2230724 and the (AG+GG) genotypes of rs1887427 had a 59% and 98% increased risk of developing gastric cancer, respectively (P = 0.010, adjusted OR = 1.59, 95% CI = 1.12–2.27; P<0.001, adjusted OR = 1.98, 95% CI = 1.39–2.81, respectively). Further stratified analysis showed that the association between the risk of gastric cancer and the rare genotypes of rs2230724 were more profound in the subgroups of elder individuals (>56 years), males, nonsmokers and urban subjects, while the association between the risk and the rare genotypes of rs1887427 persisted in subgroups of younger individuals (≤56 years), males, nonsmokers and both of rural and urban subjects. Conclusion The JAK2 gene rs2230724 and rs1887427 polymorphisms are associated with an increased risk of gastric cancer in a Chinese Han population. PMID:23717640

  2. Targeting the Interleukin-6/Jak/Stat Pathway in Human Malignancies

    PubMed Central

    Sansone, Pasquale; Bromberg, Jacqueline

    2012-01-01

    The Janus kinase/signal transducer and activator of transcription (Jak/Stat) pathway was discovered 20 years ago as a mediator of cytokine signaling. Since this time, more than 2,500 articles have been published demonstrating the importance of this pathway in virtually all malignancies. Although there are dozens of cytokines and cytokine receptors, four Jaks, and seven Stats, it seems that interleukin-6–mediated activation of Stat3 is a principal pathway implicated in promoting tumorigenesis. This transcription factor regulates the expression of numerous critical mediators of tumor formation and metastatic progression. This review will examine the relative importance and function of this pathway in nonmalignant conditions as well as malignancies (including tumor intrinsic and extrinsic), the influence of other Stats, the development of inhibitors to this pathway, and the potential role of inhibitors in controlling or eradicating cancers. PMID:22355058

  3. Identification of Small Molecule Inhibitors of Phosphatidylinositol 3-Kinase and Autophagy*

    PubMed Central

    Farkas, Thomas; Daugaard, Mads; Jäättelä, Marja

    2011-01-01

    Macroautophagy (hereafter autophagy) is a lysosomal catabolic pathway that controls cellular homeostasis and survival. It has recently emerged as an attractive target for the treatment of a variety of degenerative diseases and cancer. The targeting of autophagy has, however, been hampered by the lack of specific small molecule inhibitors. Thus, we screened two small molecule kinase inhibitor libraries for inhibitors of rapamycin-induced autophagic flux. The three most potent inhibitors identified conferred profound inhibition of autophagic flux by inhibiting the formation of autophagosomes. Notably, the autophagy inhibitory effects of all three compounds were independent of their established kinase targets, i.e. ataxia telangiectasia mutated for KU55933, protein kinase C for Gö6976, and Janus kinase 3 for Jak3 inhibitor VI. Instead, we identified phosphatidylinositol 3-kinase (PtdIns3K) as a direct target of KU55933 and Gö6976. Importantly, and in contrast to the currently available inhibitors of autophagosome formation (e.g. 3-methyladenine), none of the three compounds inhibited the cell survival promoting class I phosphoinositide 3-kinase-Akt signaling at the concentrations required for effective autophagy inhibition. Accordingly, they proved to be valuable tools for investigations of autophagy-associated cell death and survival. Employing KU55399, we demonstrated that autophagy protects amino acid-starved cells against both apoptosis and necroptosis. Taken together, our data introduce new possibilities for the experimental study of autophagy and can form a basis for the development of clinically relevant autophagy inhibitors. PMID:21930714

  4. Inactivation of JAK2/STAT3 Signaling Axis and Downregulation of M1 mAChR Cause Cognitive Impairment in klotho Mutant Mice, a Genetic Model of Aging

    PubMed Central

    Park, Seok-Joo; Shin, Eun-Joo; Min, Sun Seek; An, Jihua; Li, Zhengyi; Hee Chung, Yoon; Hoon Jeong, Ji; Bach, Jae-Hyung; Nah, Seung-Yeol; Kim, Won-Ki; Jang, Choon-Gon; Kim, Yong-Sun; Nabeshima, Yo-ichi; Nabeshima, Toshitaka; Kim, Hyoung-Chun

    2013-01-01

    We previously reported cognitive dysfunction in klotho mutant mice. In the present study, we further examined novel mechanisms involved in cognitive impairment in these mice. Significantly decreased janus kinase 2 (JAK2) and signal transducer and activator of transcription3 (STAT3) phosphorylation were observed in the hippocampus of klotho mutant mice. A selective decrease in protein expression and binding density of the M1 muscarinic cholinergic receptor (M1 mAChR) was observed in these mice. Cholinergic parameters (ie, acetylcholine (ACh), choline acetyltransferase (ChAT), and acetylcholinesterase (AChE)) and NMDAR-dependent long-term potentiation (LTP) were significantly impaired in klotho mutant mice. McN-A-343 (McN), an M1 mAChR agonist, significantly attenuated these impairments. AG490 (AG), a JAK2 inhibitor, counteracted the attenuating effects of McN, although AG did not significantly alter the McN-induced effect on AChE. Furthermore, AG significantly inhibited the attenuating effects of McN on decreased NMDAR-dependent LTP, protein kinase C βII, p-ERK, p-CREB, BDNF, and p-JAK2/p-STAT3-expression in klotho mutant mice. In addition, k252a, a BDNF receptor tyrosine kinase B (TrkB) inhibitor, significantly counteracted McN effects on decreased ChAT, ACh, and M1 mAChR and p-JAK2/p-STAT3 expression. McN-induced effects on cognitive impairment in klotho mutant mice were consistently counteracted by either AG or k252a. Our results suggest that inactivation of the JAK2/STAT3 signaling axis and M1 mAChR downregulation play a critical role in cognitive impairment observed in klotho mutant mice. PMID:23389690

  5. Combined parental obesity augments single-parent obesity effects on hypothalamus inflammation, leptin signaling (JAK/STAT), hyperphagia, and obesity in the adult mice offspring.

    PubMed

    Ornellas, Fernanda; Souza-Mello, Vanessa; Mandarim-de-Lacerda, Carlos Alberto; Aguila, Marcia Barbosa

    2016-01-01

    We aimed to evaluate the effects of maternal and/or paternal obesity on offspring body mass, leptin signaling, appetite-regulating neurotransmitters and local inflammatory markers. C57BL/6 mice received standard chow (SC, lean groups) or high-fat diet (HF, obese groups) starting from one month of age. At three months, HF mice became obese relative to SC mice. They were then mated as follows: lean mother and lean father, lean mother and obese father, obese mother and lean father, and obese mother and obese father. The offspring received the SC diet from weaning until three months of age, when they were sacrificed. In the offspring, paternal obesity did not lead to changes in the Janus kinase (JAK)/signal transducer and activation of the transcription (STAT) pathway or feeding behavior but did induce hypothalamic inflammation. On the other hand, maternal obesity resulted in increased weight gain, hyperleptinemia, decreased leptin OBRb receptor expression, JAK/STAT pathway impairment, and increased SOCS3 signaling in the offspring. In addition, maternal obesity elevated inflammatory markers and altered NPY and POMC expression in the hypothalamus. Interestingly, combined parental obesity exacerbated the deleterious outcomes compared to single-parent obesity. In conclusion, while maternal obesity is known to program metabolic changes and obesity in offspring, the current study demonstrated that obese fathers induce hypothalamus inflammation in offspring, which may contribute to the development of metabolic syndromes in adulthood.

  6. Src kinases and ERK activate distinct responses to Stitcher receptor tyrosine kinase signaling during wound healing in Drosophila.

    PubMed

    Tsarouhas, Vasilios; Yao, Liqun; Samakovlis, Christos

    2014-04-15

    Metazoans have evolved efficient mechanisms for epidermal repair and survival following injury. Several cellular responses and key signaling molecules that are involved in wound healing have been identified in Drosophila, but the coordination of cytoskeletal rearrangements and the activation of gene expression during barrier repair are poorly understood. The Ret-like receptor tyrosine kinase (RTK) Stitcher (Stit, also known as Cad96Ca) regulates both re-epithelialization and transcriptional activation by Grainy head (Grh) to induce restoration of the extracellular barrier. Here, we describe the immediate downstream effectors of Stit signaling in vivo. Drk (Downstream of receptor kinase) and Src family tyrosine kinases bind to the same docking site in the Stit intracellular domain. Drk is required for the full activation of transcriptional responses but is dispensable for re-epithelialization. By contrast, Src family kinases (SFKs) control both the assembly of a contractile actin ring at the wound periphery and Grh-dependent activation of barrier-repair genes. Our analysis identifies distinct pathways mediating injury responses and reveals an RTK-dependent activation mode for Src kinases and their central functions during epidermal wound healing in vivo.

  7. P21 activated kinase signaling in cancer.

    PubMed

    Rane, Chetan K; Minden, Audrey

    2018-01-09

    The p21 Activated Kinases (PAKs) are a family of serine threonine kinases, that consist of 6 members, PAKs 1-6, which are positioned at an intersection of multiple signaling pathways implicated in oncogenesis. The PAKs were originally identified as protein kinases that function downstream of the Ras related Rho GTPases Cdc42 and Rac. PAK1 and PAK4, which belong to Group I and Group II PAKs, respectively, are most often associated with tumorigenesis. On account of their well characterized roles in cancer, several small molecule inhibitors are being developed to inhibit the PAKs, and there is interest in investigating their efficacy as either first line or adjuvant treatments for cancer. Studies to delineate PAK regulated signaling pathways as well as the long term effects of PAK overexpression on gene expression are beginning to shed light on the mechanism by which PAK proteins may lead to cancer when they are overexpressed or activated. This review will describe the association between PAK expression in cancer, with a focus on PAK1 and PAK4, which are most often associated with the disease. The current understanding of the molecular mechanisms by which the PAKs operate in cancer will be discussed. We will also review some of the potential drug candidates, and discuss which of them are currently being tested for their efficacy in cancer treatments. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Nano-optomechanical transducer

    DOEpatents

    Rakich, Peter T; El-Kady, Ihab F; Olsson, Roy H; Su, Mehmet Fatih; Reinke, Charles; Camacho, Ryan; Wang, Zheng; Davids, Paul

    2013-12-03

    A nano-optomechanical transducer provides ultrabroadband coherent optomechanical transduction based on Mach-wave emission that uses enhanced photon-phonon coupling efficiencies by low impedance effective phononic medium, both electrostriction and radiation pressure to boost and tailor optomechanical forces, and highly dispersive electromagnetic modes that amplify both electrostriction and radiation pressure. The optomechanical transducer provides a large operating bandwidth and high efficiency while simultaneously having a small size and minimal power consumption, enabling a host of transformative phonon and signal processing capabilities. These capabilities include optomechanical transduction via pulsed phonon emission and up-conversion, broadband stimulated phonon emission and amplification, picosecond pulsed phonon lasers, broadband phononic modulators, and ultrahigh bandwidth true time delay and signal processing technologies.

  9. Intracellular Signaling by Hydrolysis of Phospholipids and Activation of Protein Kinase C

    NASA Astrophysics Data System (ADS)

    Nishizuka, Yasutomi

    1992-10-01

    Hydrolysis of inositol phospholipids by phospholipase C is initiated by either receptor stimulation or opening of Ca2+ channels. This was once thought to be the sole mechanism to produce the diacylglycerol that links extracellular signals to intracellular events through activation of protein kinase C. It is becoming clear that agonist-induced hydrolysis of other membrane phospholipids, particularly choline phospholipids, by phospholipase D and phospholipase A_2 may also take part in cell signaling. The products of hydrolysis of these phospholipids may enhance and prolong the activation of protein kinase C. Such prolonged activation of protein kinase C is essential for long-term cellular responses such as cell proliferation and differentiation.

  10. Smart transducer with radiomodem

    NASA Astrophysics Data System (ADS)

    Pugach, V. N.; Voronin, E. L.

    2018-04-01

    Systems for measuring different parameters enabling metering and wireless data transmission are an urgent problem in the industry. One of the most promising solutions is the developments of metering instruments enabling radio-link and GSM data transmission. The article describes a transducer operating with temperature sensors of different types as well as with the sensors of other physical values with the output signal represented as current or voltage with subsequent measurement data transmission from the transducer to the computer via radio-link. The article provides transducer measurement accuracy check. The work confirmed the claimed temperature measurement accuracy, noted a stable data transmission via radio link and convenience of work with the transducer and software.

  11. Receptor-mediated protein kinase activation and the mechanism of transmembrane signaling in bacterial chemotaxis.

    PubMed Central

    Liu, Y; Levit, M; Lurz, R; Surette, M G; Stock, J B

    1997-01-01

    Chemotaxis responses of Escherichia coli and Salmonella are mediated by type I membrane receptors with N-terminal extracytoplasmic sensing domains connected by transmembrane helices to C-terminal signaling domains in the cytoplasm. Receptor signaling involves regulation of an associated protein kinase, CheA. Here we show that kinase activation by a soluble signaling domain construct involves the formation of a large complex, with approximately 14 receptor signaling domains per CheA dimer. Electron microscopic examination of these active complexes indicates a well defined bundle composed of numerous receptor filaments. Our findings suggest a mechanism for transmembrane signaling whereby stimulus-induced changes in lateral packing interactions within an array of receptor-sensing domains at the cell surface perturb an equilibrium between active and inactive receptor-kinase complexes within the cytoplasm. PMID:9405352

  12. Pelle kinase is activated by autophosphorylation during Toll signaling in Drosophila.

    PubMed

    Shen, Baohe; Manley, James L

    2002-04-01

    The Drosophila Pelle kinase plays a key role in the evolutionarily conserved Toll signaling pathway, but the mechanism responsible for its activation has been unknown. We present in vivo and in vitro evidence establishing an important role for concentration-dependent autophosphorylation in the signaling process. We first show that Pelle phosphorylation can be detected transiently in early embryos, concomitant with activation of signaling. Importantly, Pelle phosphorylation is enhanced in a gain-of-function Toll mutant (Toll(10b)), but decreased by loss-of-function Toll alleles. Next we found that Pelle is phosphorylated in transfected Schneider L2 cells in a concentration-dependent manner such that significant modification is observed only at high Pelle concentrations, which coincide with levels required for phosphorylation and activation of the downstream target, Dorsal. Pelle phosphorylation is also enhanced in L2 cells co-expressing Toll(10b), and is dependent on Pelle kinase activity. In vitro kinase assays revealed that recombinant, autophosphorylated Pelle is far more active than unphosphorylated Pelle. Importantly, unphosphorylated Pelle becomes autophosphorylated, and activated, by incubation at high concentrations. We discuss these results in the context of Toll-like receptor mediated signaling in both flies and mammals.

  13. Signaling, Regulation, and Specificity of the Type II p21-activated Kinases.

    PubMed

    Ha, Byung Hak; Morse, Elizabeth M; Turk, Benjamin E; Boggon, Titus J

    2015-05-22

    The p21-activated kinases (PAKs) are a family of six serine/threonine kinases that act as key effectors of RHO family GTPases in mammalian cells. PAKs are subdivided into two groups: type I PAKs (PAK1, PAK2, and PAK3) and type II PAKs (PAK4, PAK5, and PAK6). Although these groups are involved in common signaling pathways, recent work indicates that the two groups have distinct modes of regulation and have both unique and common substrates. Here, we review recent insights into the molecular level details that govern regulation of type II PAK signaling. We also consider mechanisms by which signal transduction is regulated at the level of substrate specificity. Finally, we discuss the implications of these studies for clinical targeting of these kinases. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. Angiotensin II regulation of neuromodulation: downstream signaling mechanism from activation of mitogen-activated protein kinase.

    PubMed

    Lu, D; Yang, H; Raizada, M K

    1996-12-01

    Angiotensin II (Ang II) stimulates expression of tyrosine hydroxylase and norepinephrine transporter genes in brain neurons; however, the signal-transduction mechanism is not clearly defined. This study was conducted to determine the involvement of the mitogen-activated protein (MAP) kinase signaling pathway in Ang II stimulation of these genes. MAP kinase was localized in the perinuclear region of the neuronal soma. Ang II caused activation of MAP kinase and its subsequent translocation from the cytoplasmic to nuclear compartment, both effects being mediated by AT1 receptor subtype. Ang II also stimulated SRE- and AP1-binding activities and fos gene expression and its translocation in a MAP kinase-dependent process. These observations are the first demonstration of a downstream signaling pathway involving MAP kinase in Ang II-mediated neuromodulation in noradrenergic neurons.

  15. Neuronal suppressor of cytokine signaling-3 deficiency enhances hypothalamic leptin-dependent phosphatidylinositol 3-kinase signaling.

    PubMed

    Metlakunta, Anantha S; Sahu, Maitrayee; Yasukawa, Hideo; Dhillon, Sandeep S; Belsham, Denise D; Yoshimura, Akihiko; Sahu, Abhiram

    2011-05-01

    Suppressor of cytokine signaling-3 (SOCS3) is thought to be involved in the development of central leptin resistance and obesity by inhibiting STAT3 pathway. Because phosphatidylinositol 3-kinase (PI3K) pathway plays an important role in transducing leptin action in the hypothalamus, we examined whether SOCS3 exerted an inhibition on this pathway. We first determined whether leptin sensitivity in the hypothalamic PI3K pathway was increased in brain-specific Socs3-deficient (NesKO) mice. In NesKO mice, hypothalamic insulin receptor substrate-1 (IRS1)-associated PI3K activity was significantly increased at 30 min and remained elevated up to 2 h after leptin intraperitoneal injection, but in wild-type (WT) littermates, the significant increase was only at 30 min. Hypothalamic p-STAT3 levels were increased up to 5 h in NesKO as opposed to 2 h in WT mice. In food-restricted WT mice with reduced body weight, leptin increased hypothalamic PI3K activity only at 30 min, and p-STAT3 levels at 30-120 min postinjection. These results suggest increased leptin sensitivity in both PI3K and STAT3 pathways in the hypothalamus of NesKO mice, which was not due to a lean phenotype. In the next experiment with a clonal hypothalamic neuronal cell line expressing proopiomelanocortin, we observed that whereas leptin significantly increased IRS1-associated PI3K activity and p-JAK2 levels in cells transfected with control vector, it failed to do so in SOCS3-overexpressed cells. Altogether, these results imply a SOCS3 inhibition of the PI3K pathway of leptin signaling in the hypothalamus, which may be one of the mechanisms behind the development of central leptin resistance and obesity.

  16. Neuronal suppressor of cytokine signaling-3 deficiency enhances hypothalamic leptin-dependent phosphatidylinositol 3-kinase signaling

    PubMed Central

    Metlakunta, Anantha S.; Sahu, Maitrayee; Yasukawa, Hideo; Dhillon, Sandeep S.; Belsham, Denise D.; Yoshimura, Akihiko

    2011-01-01

    Suppressor of cytokine signaling-3 (SOCS3) is thought to be involved in the development of central leptin resistance and obesity by inhibiting STAT3 pathway. Because phosphatidylinositol 3-kinase (PI3K) pathway plays an important role in transducing leptin action in the hypothalamus, we examined whether SOCS3 exerted an inhibition on this pathway. We first determined whether leptin sensitivity in the hypothalamic PI3K pathway was increased in brain-specific Socs3-deficient (NesKO) mice. In NesKO mice, hypothalamic insulin receptor substrate-1 (IRS1)-associated PI3K activity was significantly increased at 30 min and remained elevated up to 2 h after leptin intraperitoneal injection, but in wild-type (WT) littermates, the significant increase was only at 30 min. Hypothalamic p-STAT3 levels were increased up to 5 h in NesKO as opposed to 2 h in WT mice. In food-restricted WT mice with reduced body weight, leptin increased hypothalamic PI3K activity only at 30 min, and p-STAT3 levels at 30–120 min postinjection. These results suggest increased leptin sensitivity in both PI3K and STAT3 pathways in the hypothalamus of NesKO mice, which was not due to a lean phenotype. In the next experiment with a clonal hypothalamic neuronal cell line expressing proopiomelanocortin, we observed that whereas leptin significantly increased IRS1-associated PI3K activity and p-JAK2 levels in cells transfected with control vector, it failed to do so in SOCS3-overexpressed cells. Altogether, these results imply a SOCS3 inhibition of the PI3K pathway of leptin signaling in the hypothalamus, which may be one of the mechanisms behind the development of central leptin resistance and obesity. PMID:21325649

  17. EBV-driven B-cell lymphoproliferative disorders: from biology, classification and differential diagnosis to clinical management

    PubMed Central

    Ok, Chi Young; Li, Ling; Young, Ken H

    2015-01-01

    Epstein–Barr virus (EBV) is a ubiquitous herpesvirus, affecting >90% of the adult population. EBV targets B-lymphocytes and achieves latent infection in a circular episomal form. Different latency patterns are recognized based on latent gene expression pattern. Latent membrane protein-1 (LMP-1) mimics CD40 and, when self-aggregated, provides a proliferation signal via activating the nuclear factor-kappa B, Janus kinase/signal transducer and activator of transcription, phosphoinositide 3-kinase/Akt (PI3K/Akt) and mitogen-activated protein kinase pathways to promote cellular proliferation. LMP-1 also induces BCL-2 to escape from apoptosis and gives a signal for cell cycle progression by enhancing cyclin-dependent kinase 2 and phosphorylation of retinoblastoma (Rb) protein and by inhibiting p16 and p27. LMP-2A blocks the surface immunoglobulin-mediated lytic cycle reactivation. It also activates the Ras/PI3K/Akt pathway and induces Bcl-xL expression to promote B-cell survival. Recent studies have shown that ebv-microRNAs can provide extra signals for cellular proliferation, cell cycle progression and anti-apoptosis. EBV is well known for association with various types of B-lymphocyte, T-lymphocyte, epithelial cell and mesenchymal cell neoplasms. B-cell lymphoproliferative disorders encompass a broad spectrum of diseases, from benign to malignant. Here we review our current understanding of EBV-induced lymphomagenesis and focus on biology, diagnosis and management of EBV-associated B-cell lymphoproliferative disorders. PMID:25613729

  18. Protein tyrosine kinase and mitogen-activated protein kinase signalling pathways contribute to differences in heterophil-mediated innate immune responsiveness between two lines of broilers

    USDA-ARS?s Scientific Manuscript database

    Protein tyrosine phosphorylation mediates signal transduction of cellular processes, with protein tyrosine kinases (PTKs) regulating virtually all signaling events. The mitogen-activated protein kinase (MAPK) super-family consists of three conserved pathways that convert receptor activation into ce...

  19. MAP kinase-independent signaling in angiotensin II regulation of neuromodulation in SHR neurons.

    PubMed

    Yang, H; Raizada, M K

    1998-09-01

    Angiotensin II (Ang II), via its interaction with the angiotensin type 1 (AT1) receptor subtype, causes enhanced stimulation of norepinephrine (NE) neuromodulation. This involves increased transcription of NE transporter, tyrosine hydroxylase, and dopamine ss-hydroxylase genes in Wistar-Kyoto rat (WKY) brain neurons. AT1 receptor-mediated regulation of certain signaling events (such as activation of the Ras-Raf-1-mitogen activated protein (MAP) kinase signaling pathway, nuclear translocation of transcription factors such as Fos and Jun, and the interactions of these factors with AP-1 binding sites) is involved in this NE neuromodulation (Lu et al. J Cell Biol. 1996;135:1609-1617). The aim of this study was to compare the signal transduction mechanism of Ang II regulation of NE neuromodulation in WKY and spontaneously hypertensive rat (SHR) brain neurons, in view of the fact that AT1 receptor expression and Ang II stimulation of NE neuromodulation are higher in SHR neurons compared with WKY neurons. Despite this hyperactivity, Ang II stimulation of Ras, Raf-1, and MAP kinase activities was comparable between the neurons from WKY and SHR. Similarly, central injections of Ang II caused a comparable stimulation of MAP kinase in the hypothalamic and brain stem areas of adult WKY and SHR. Inhibition of MAP kinase by either an MAP kinase kinase inhibitor (PD98059) or an MAP kinase antisense oligonucleotide completely attenuated the stimulatory effects of Ang II on [3H]-NE uptake, NE transporter mRNA, and tyrosine hydroxylase mRNA levels in WKY neurons. These treatments resulted in only 43% to 50% inhibition of [3H]-NE uptake and NE transporter and tyrosine hydroxylase mRNAs in SHR neurons. Thus, Ang II stimulation of NE neuromodulation was completely blocked by MAP kinase inhibition in WKY neurons and only partially blocked in the SHR neurons. These observations suggest the presence of an additional signal transduction pathway involved in NE neuromodulation in SHR neurons

  20. Protein kinase N2 regulates AMP kinase signaling and insulin responsiveness of glucose metabolism in skeletal muscle.

    PubMed

    Ruby, Maxwell A; Riedl, Isabelle; Massart, Julie; Åhlin, Marcus; Zierath, Juleen R

    2017-10-01

    Insulin resistance is central to the development of type 2 diabetes and related metabolic disorders. Because skeletal muscle is responsible for the majority of whole body insulin-stimulated glucose uptake, regulation of glucose metabolism in this tissue is of particular importance. Although Rho GTPases and many of their affecters influence skeletal muscle metabolism, there is a paucity of information on the protein kinase N (PKN) family of serine/threonine protein kinases. We investigated the impact of PKN2 on insulin signaling and glucose metabolism in primary human skeletal muscle cells in vitro and mouse tibialis anterior muscle in vivo. PKN2 knockdown in vitro decreased insulin-stimulated glucose uptake, incorporation into glycogen, and oxidation. PKN2 siRNA increased 5'-adenosine monophosphate-activated protein kinase (AMPK) signaling while stimulating fatty acid oxidation and incorporation into triglycerides and decreasing protein synthesis. At the transcriptional level, PKN2 knockdown increased expression of PGC-1α and SREBP-1c and their target genes. In mature skeletal muscle, in vivo PKN2 knockdown decreased glucose uptake and increased AMPK phosphorylation. Thus, PKN2 alters key signaling pathways and transcriptional networks to regulate glucose and lipid metabolism. Identification of PKN2 as a novel regulator of insulin and AMPK signaling may provide an avenue for manipulation of skeletal muscle metabolism. Copyright © 2017 the American Physiological Society.

  1. SOCS3

    PubMed Central

    Yasukawa, Hideo; Nagata, Takanobu; Oba, Toyoharu; Imaizumi, Tsutomu

    2012-01-01

    The suppressors of cytokine signaling (SOCS) family of proteins are cytokine-inducible inhibitors of Janus kinase (JAK)-signal transducer and activator of the transcription (STAT) signaling pathways. Among the family, SOCS1 and SOCS3 potently suppress cytokine actions by inhibiting JAK kinase activities. The generation of mice lacking individual SOCS genes has been instrumental in defining the role of individual SOCS proteins in specific cytokine pathways in vivo; SOCS1 is an essential negative regulator of interferon-γ (IFNγ) and SOCS3 is an essential negative regulator of leukemia inhibitory factor (LIF). JAK-STAT3 activating cytokines have exhibited cardioprotective roles in the heart. The cardiac-specific deletion of SOCS3 enhances the activation of cardioprotective signaling pathways, inhibits myocardial apoptosis and fibrosis and results in the inhibition of left ventricular remodeling after myocardial infarction (MI). We propose that myocardial SOCS3 is a key determinant of left ventricular remodeling after MI, and SOCS3 may serve as a novel therapeutic target to prevent left ventricular remodeling after MI. In this review, we discuss the signaling pathways mediated by JAK-STAT and SOCS proteins and their roles in the development of myocardial injury under stress (e.g., pressure overload, viral infection and ischemia). PMID:24058778

  2. Characterization of noncontact piezoelectric transducer with conically shaped piezoelement

    NASA Technical Reports Server (NTRS)

    Williams, James H., Jr.; Ochi, Simeon C. U.

    1988-01-01

    The characterization of a dynamic surface displacement transducer (IQI Model 501) by a noncontact method is presented. The transducer is designed for ultrasonic as well as acoustic emission measurements and, according to the manufacturer, its characteristic features include a flat frequency response range which is from 50 to 1000 kHz and a quality factor Q of less than unity. The characterization is based on the behavior of the transducer as a receiver and involves exciting the transducer directly by transient pulse input stress signals of quasi-electrostatic origin and observing its response in a digital storage oscilloscope. Theoretical models for studying the response of the transducer to pulse input stress signals and for generating pulse stress signals are presented. The characteristic features of the transducer which include the central frequency f sub o, quality factor Q, and flat frequency response range are obtained by this noncontact characterization technique and they compare favorably with those obtained by a tone burst method which are also presented.

  3. The discovery of a reciprocal relationship between tyrosine-kinase signaling and cullin neddylation.

    PubMed

    Friend, Samantha F; Peterson, Lisa K; Treacy, Eric; Stefanski, Adrianne L; Sosinowski, Tomasz; Pennock, Nathan D; Berger, Allison J; Winn, Virginia D; Dragone, Leonard L

    2013-01-01

    While neddylation is known to activate cullin (CUL)-RING ubiquitin ligases (CRLs), its role in regulating T cell signaling is poorly understood. Using the investigational NEDD8 activating enzyme (NAE) inhibitor, MLN4924, we found that neddylation negatively regulates T cell receptor (TCR) signaling, as its inhibition increases IL-2 production, T cell proliferation and Treg development in vitro. We also discovered that loss of CUL neddylation occurs upon TCR signaling, and CRLs negatively regulate IL-2 production. Additionally, we found that tyrosine kinase signaling leads to CUL deneddylation in multiple cell types. These studies indicate that CUL neddylation is a global regulatory mechanism for tyrosine kinase signaling.

  4. Pressure-Transducer Simulator

    NASA Technical Reports Server (NTRS)

    Simon, Richard A.

    1987-01-01

    Simulation circuit operates under remote, automatic, or manual control to produce electrical outputs similar to pressure transducer. Specific circuit designed for simulations of Space Shuttle main engine. General circuit concept adaptable to other simulation and control systems involving several operating modes. Switches and amplifiers respond to external control signals and panel control settings to vary differential excitation of resistive bridge. Output voltage or passive terminal resistance made to equal pressure transducer in any of four operating modes.

  5. Cardiovascular safety findings in patients with rheumatoid arthritis treated with tofacitinib, an oral Janus kinase inhibitor.

    PubMed

    Charles-Schoeman, Christina; Wicker, Pierre; Gonzalez-Gay, Miguel A; Boy, Mary; Zuckerman, Andrea; Soma, Koshika; Geier, Jamie; Kwok, Kenneth; Riese, Richard

    2016-12-01

    Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis (RA). The implications of treatment with tofacitinib on cardiovascular (CV) risk in RA are unknown. Therefore, CV adverse events (AEs), and blood pressure and lipid level changes, in tofacitinib-treated patients with RA were evaluated. Data were pooled from six Phase (P)3 studies (24 months) and two open-label long-term extension (LTE) studies (60 months) of tofacitinib in patients with RA and inadequate response to DMARDs. Tofacitinib was administered alone or with non-biologic DMARDs. CV events, including major adverse CV events (MACE: CV death and non-fatal CV events) and congestive heart failure (CHF), were assessed by a blinded adjudication committee. Overall, 4271 patients from P3 studies and 4827 enrolled from P2/P3 studies into LTE studies were evaluated, representing 3942 and 8699 patient-years of exposure to tofacitinib, respectively. Blood pressure remained stable over time across studies. The number of investigator-reported hypertension-related AEs in tofacitinib-treated patients was low in P3 studies (Months 0-3: 2.8%; Months 3-6: 1.4%; >6 months: 2.8%). Across studies, lipid level increases were generally observed within 1-3 months of treatment and stabilized thereafter. Patients with events (incidence rate [IR]/100 patient-years) for MACE and CHF, respectively, were: 23 (0.58) and 9 (0.23) in P3 studies, and 32 (0.37) and 8 (0.09) in LTE studies; IRs were comparable with placebo (P3) and did not increase over time (LTE). Tofacitinib was associated with a low incidence of CV events in a large Phase 3 program, including LTE studies. Further long-term studies are underway. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  6. ROP GTPase-mediated auxin signaling regulates pavement cell interdigitation in Arabidopsis thaliana.

    PubMed

    Lin, Deshu; Ren, Huibo; Fu, Ying

    2015-01-01

    In multicellular plant organs, cell shape formation depends on molecular switches to transduce developmental or environmental signals and to coordinate cell-to-cell communication. Plants have a specific subfamily of the Rho GTPase family, usually called Rho of Plants (ROP), which serve as a critical signal transducer involved in many cellular processes. In the last decade, important advances in the ROP-mediated regulation of plant cell morphogenesis have been made by using Arabidopsis thaliana leaf and cotyledon pavement cells. Especially, the auxin-ROP signaling networks have been demonstrated to control interdigitated growth of pavement cells to form jigsaw-puzzle shapes. Here, we review findings related to the discovery of this novel auxin-signaling mechanism at the cell surface. This signaling pathway is to a large extent independent of the well-known Transport Inhibitor Response (TIR)-Auxin Signaling F-Box (AFB) pathway, and instead requires Auxin Binding Protein 1 (ABP1) interaction with the plasma membrane-localized, transmembrane kinase (TMK) receptor-like kinase to regulate ROP proteins. Once activated, ROP influences cytoskeletal organization and inhibits endocytosis of the auxin transporter PIN1. The present review focuses on ROP signaling and its self-organizing feature allowing ROP proteins to serve as a bustling signal decoder and integrator for plant cell morphogenesis. © 2014 Institute of Botany, Chinese Academy of Sciences.

  7. PDK1: A signaling hub for cell migration and tumor invasion.

    PubMed

    Gagliardi, Paolo Armando; di Blasio, Laura; Primo, Luca

    2015-12-01

    The ability of cells to migrate is essential for different physiological processes including embryonic development, angiogenesis, tissue repair and immune response. In the context of cancer such abilities acquire dramatic implications, as they are exploited by tumor cells to invade neighboring or distant healthy tissues. 3-Phosphoinositide dependent protein kinase-1 (PDK1 or PDPK1) is an ancient serine-threonine kinase belonging to AGC kinase family. An increasing amount of data points at a pivotal role for PDK1 in the regulation of cell migration. PDK1 is a transducer of PI3K signaling and activates multiple downstream effectors, thereby representing an essential hub coordinating signals coming from extracellular cues to the cytoskeletal machinery, the final executor of cell movement. Akt, PAK1, β3 integrin, ROCK1, MRCKα and PLCγ1 are, according to the literature, the signaling transducers through which PDK1 regulates cell migration. In addition, PDK1 contributes to tumor cell invasion by regulating invadopodia formation and both amoeboid and collective cancer cell invasion. This and other pieces of evidence, such as its reported overexpression across several tumor types, corroborate a PDK1 role tumor aggressiveness. Altogether, these findings indicate the possibility to rationally target PDK1 in human tumors in order to counteract cancer cell dissemination in the organism. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. MEK inhibition prevents tumour-shed transforming growth factor-β-induced T-regulatory cell augmentation in tumour milieu.

    PubMed

    Hossain, Dewan M S; Panda, Abir K; Chakrabarty, Sreeparna; Bhattacharjee, Pushpak; Kajal, Kirti; Mohanty, Suchismita; Sarkar, Irene; Sarkar, Diptendra K; Kar, Santosh K; Sa, Gaurisankar

    2015-04-01

    Tumour progression is associated with immune-suppressive conditions that facilitate the escape of tumour cells from the regimen of immune cells, subsequently paralysing the host defence mechanisms. Induction of CD4(+)  CD25(+)  FoxP3(+) T regulatory (Treg) cells has been implicated in the tumour immune escape mechanism, although the novel anti-cancer treatment strategies targeting Treg cells remain unknown. The focus of this study is to define the interaction between tumour and immune system, i.e. how immune tolerance starts and gradually leads to the induction of adaptive Treg cells in the tumour microenvironment. Our study identified hyperactivated mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) -signalling as a potential target for reversing Treg cell augmentation in breast cancer patients. In more mechanistic detail, pharmacological inhibitors of MEK/ERK signalling inhibited transforming growth factor-β (TGF-β) production in tumour cells that essentially blocked TGF-β-SMAD3/SMAD4-mediated induction of CD25/interleukin-2 receptor α on CD4(+) T-cell surface. As a result high-affinity binding of interleukin-2 on those cells was prohibited, causing lack of Janus kinase 1 (JAK1)/JAK3-mediated signal transducer and activator of transcription 3 (STAT3)/STAT5 activation required for FoxP3 expression. Finally, for a more radical approach towards a safe MEK inhibitor, we validate the potential of multi-kinase inhibitor curcumin, especially the nano-curcumin made out of pure curcumin with greater bioavailability; in repealing tumour-shed TGF-β-induced Treg cell augmentation. © 2014 Bose Institute.

  9. MEK inhibition prevents tumour-shed transforming growth factor-β-induced T-regulatory cell augmentation in tumour milieu

    PubMed Central

    Hossain, Dewan M S; Panda, Abir K; Chakrabarty, Sreeparna; Bhattacharjee, Pushpak; Kajal, Kirti; Mohanty, Suchismita; Sarkar, Irene; Sarkar, Diptendra K; Kar, Santosh K; Sa, Gaurisankar

    2015-01-01

    Tumour progression is associated with immune-suppressive conditions that facilitate the escape of tumour cells from the regimen of immune cells, subsequently paralysing the host defence mechanisms. Induction of CD4+ CD25+ FoxP3+ T regulatory (Treg) cells has been implicated in the tumour immune escape mechanism, although the novel anti-cancer treatment strategies targeting Treg cells remain unknown. The focus of this study is to define the interaction between tumour and immune system, i.e. how immune tolerance starts and gradually leads to the induction of adaptive Treg cells in the tumour microenvironment. Our study identified hyperactivated mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) -signalling as a potential target for reversing Treg cell augmentation in breast cancer patients. In more mechanistic detail, pharmacological inhibitors of MEK/ERK signalling inhibited transforming growth factor-β (TGF-β) production in tumour cells that essentially blocked TGF-β-SMAD3/SMAD4-mediated induction of CD25/interleukin-2 receptor α on CD4+ T-cell surface. As a result high-affinity binding of interleukin-2 on those cells was prohibited, causing lack of Janus kinase 1 (JAK1)/JAK3-mediated signal transducer and activator of transcription 3 (STAT3)/STAT5 activation required for FoxP3 expression. Finally, for a more radical approach towards a safe MEK inhibitor, we validate the potential of multi-kinase inhibitor curcumin, especially the nano-curcumin made out of pure curcumin with greater bioavailability; in repealing tumour-shed TGF-β-induced Treg cell augmentation. PMID:25284464

  10. Curvature-Mediated Assembly of Janus Nanoparticles on Membrane Vesicles.

    PubMed

    Bahrami, Amir Houshang; Weikl, Thomas R

    2018-02-14

    Besides direct particle-particle interactions, nanoparticles adsorbed to biomembranes experience indirect interactions that are mediated by the membrane curvature arising from particle adsorption. In this Letter, we show that the curvature-mediated interactions of adsorbed Janus particles depend on the initial curvature of the membrane prior to adsorption, that is, on whether the membrane initially bulges toward or away from the particles in our simulations. The curvature-mediated interaction can be strongly attractive for Janus particles adsorbed to the outside of a membrane vesicle, which initially bulges away from the particles. For Janus particles adsorbed to the vesicle inside, in contrast, the curvature-mediated interactions are repulsive. We find that the area fraction of the adhesive Janus particle surface is an important control parameter for the curvature-mediated interaction and assembly of the particles, besides the initial membrane curvature.

  11. Histone deacetylase 3 supports endochondral bone formation by controlling cytokine signaling and matrix remodeling

    PubMed Central

    Carpio, Lomeli R.; Bradley, Elizabeth W.; McGee-Lawrence, Meghan E.; Weivoda, Megan M.; Poston, Daniel D.; Dudakovic, Amel; Xu, Ming; Tchkonia, Tamar; Kirkland, James L.; van Wijnen, Andre J.; Oursler, Merry Jo; Westendorf, Jennifer J.

    2017-01-01

    Histone deacetylase (HDAC) inhibitors are efficacious epigenetic-based therapies for some cancers and neurological disorders; however, each of these drugs inhibits multiple HDACs and has detrimental effects on the skeleton. To better understand how HDAC inhibitors affect endochondral bone formation, we conditionally deleted one of their targets, Hdac3, pre- and postnatally in type II collagen α1 (Col2α1)–expressing chondrocytes. Embryonic deletion was lethal, but postnatal deletion of Hdac3 delayed secondary ossification center formation, altered maturation of growth plate chondrocytes, and increased osteoclast activity in the primary spongiosa. HDAC3-deficient chondrocytes exhibited increased expression of cytokine and matrix-degrading genes (Il-6, Mmp3, Mmp13, and Saa3) and a reduced abundance of genes related to extracellular matrix production, bone development, and ossification (Acan, Col2a1, Ihh, and Col10a1). Histone acetylation increased at and near genes that had increased expression. The acetylation and activation of nuclear factor κB (NF-κB) were also increased in HDAC3-deficient chondrocytes. Increased cytokine signaling promoted autocrine activation of Janus kinase (JAK)–signal transducer and activator of transcription (STAT) and NF-κB pathways to suppress chondrocyte maturation, as well as paracrine activation of osteoclasts and bone resorption. Blockade of interleukin-6 (IL-6)–JAK–STAT signaling, NF-κB signaling, and bromodomain extraterminal proteins, which recognize acetylated lysines and promote transcriptional elongation, significantly reduced Il-6 and Mmp13 expression in HDAC3-deficient chondrocytes and secondary activation in osteoclasts. The JAK inhibitor ruxolitinib also reduced osteoclast activity in Hdac3 conditional knockout mice. Thus, HDAC3 controls the temporal and spatial expression of tissue-remodeling genes and inflammatory responses in chondrocytes to ensure proper endochondral ossification during development. PMID

  12. Role of nongenomic activation of phosphatidylinositol 3-kinase/Akt and mitogen-activated protein kinase/extracellular signal-regulated kinase kinase/extracellular signal-regulated kinase 1/2 pathways in 1,25D3-mediated apoptosis in squamous cell carcinoma cells.

    PubMed

    Ma, Yingyu; Yu, Wei-Dong; Kong, Rui-Xian; Trump, Donald L; Johnson, Candace S

    2006-08-15

    Vitamin D is a steroid hormone that regulates calcium homeostasis and bone metabolism. The active form of vitamin D [1 alpha,25-dihydroxyvitamin D(3) (1,25D3)] acts through both genomic and nongenomic pathways. 1,25D3 has antitumor effects in a variety of cancers, including colorectal, prostate, breast, ovarian, and skin cancers. 1,25D3 exerts growth-inhibitory effects in cancer cells through the induction of apoptosis, cell cycle arrest, and differentiation. The mechanisms regulating 1,25D3-induced apoptosis remain unclear. We investigated the role of nongenomic signaling in 1,25D3-mediated apoptosis in squamous cell carcinoma (SCC) cells. 1,25D3 induced rapid and sustained activation of phosphatidylinositol 3-kinase/Akt and mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) 1/2 pathways in SCC cells. These effects were nongenomic: they occurred rapidly and were not inhibited by cycloheximide or actinomycin D. To examine whether the nongenomic activation of Akt and ERK1/2 plays a role in 1,25D3-mediated apoptosis, the expression of Akt or ERK1/2 was reduced by small interfering RNA (siRNA). siRNA-Akt significantly enhanced 1,25D3-induced apoptosis as indicated by increased levels of Annexin V-positive cells and increased sub-G(1) population and DNA fragmentation. In contrast, siRNA-ERK1/2 had no effects on 1,25D3-induced apoptosis. In addition, siRNA-Akt transfection followed by 1,25D3 treatment induced apoptosis much sooner than 1,25D3 alone. siRNA-Akt and 1,25D3 induced caspase-10 activation, suppressed the expression of c-IAP1 and XIAP, and promoted 1,25D3-induced caspase-3 activation. These results support a link between 1,25D3-induced nongenomic signaling and apoptosis. 1,25D3 induces the activation of phosphatidylinositol 3-kinase/Akt, which suppresses 1,25D3-mediated apoptosis and prolongs the survival of SCC cells.

  13. Responses to Cytokines and Interferons that Depend upon JAKs and STATs.

    PubMed

    Stark, George R; Cheon, HyeonJoo; Wang, Yuxin

    2018-01-02

    Many cytokines and all interferons activate members of a small family of kinases (the Janus kinases [JAKs]) and a slightly larger family of transcription factors (the signal transducers and activators of transcription [STATs]), which are essential components of pathways that induce the expression of specific sets of genes in susceptible cells. JAK-STAT pathways are required for many innate and acquired immune responses, and the activities of these pathways must be finely regulated to avoid major immune dysfunctions. Regulation is achieved through mechanisms that include the activation or induction of potent negative regulatory proteins, posttranslational modification of the STATs, and other modulatory effects that are cell-type specific. Mutations of JAKs and STATs can result in gains or losses of function and can predispose affected individuals to autoimmune disease, susceptibility to a variety of infections, or cancer. Here we review recent developments in the biochemistry, genetics, and biology of JAKs and STATs. Copyright © 2018 Cold Spring Harbor Laboratory Press; all rights reserved.

  14. STATs in NK-Cells: The Good, the Bad, and the Ugly.

    PubMed

    Gotthardt, Dagmar; Sexl, Veronika

    2016-01-01

    Natural killer (NK)-cells are major players in the fight against viral infections and transformed cells, but there is increasing evidence attributing a disease-promoting role to NK-cells. Cytokines present in the tumor microenvironment shape NK-cell maturation, function, and effector responses. Many cytokines signal via the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway that is also frequently altered and constitutively active in a broad range of tumor cells. As a consequence, there are currently major efforts to develop therapeutic strategies to target this pathway. Therefore, it is of utmost importance to understand the role and contributions of JAK-STAT molecules in NK-cell biology-only this knowledge will allow us to predict effects of JAK-STAT inhibition for NK-cell functions and to successfully apply precision medicine. We will review the current knowledge on the role of JAK-STAT signaling for NK-cell functions and discuss conditions involved in the switch from NK-cell tumor surveillance to disease promotion.

  15. Genetic loss of SH2B3 in acute lymphoblastic leukemia.

    PubMed

    Perez-Garcia, Arianne; Ambesi-Impiombato, Alberto; Hadler, Michael; Rigo, Isaura; LeDuc, Charles A; Kelly, Kara; Jalas, Chaim; Paietta, Elisabeth; Racevskis, Janis; Rowe, Jacob M; Tallman, Martin S; Paganin, Maddalena; Basso, Giuseppe; Tong, Wei; Chung, Wendy K; Ferrando, Adolfo A

    2013-10-03

    The SH2B adaptor protein 3 (SH2B3) gene encodes a negative regulator of cytokine signaling with a critical role in the homeostasis of hematopoietic stem cells and lymphoid progenitors. Here, we report the identification of germline homozygous SH2B3 mutations in 2 siblings affected with developmental delay and autoimmunity, one in whom B-precursor acute lymphoblastic leukemia (ALL) developed. Mechanistically, loss of SH2B3 increases Janus kinase-signal transducer and activator of transcription signaling, promotes lymphoid cell proliferation, and accelerates leukemia development in a mouse model of NOTCH1-induced ALL. Moreover, extended mutation analysis showed homozygous somatic mutations in SH2B3 in 2 of 167 ALLs analyzed. Overall, these results demonstrate a Knudson tumor suppressor role for SH2B3 in the pathogenesis of ALL and highlight a possible link between genetic predisposition factors in the pathogenesis of autoimmunity and leukemogenesis.

  16. Drosophila Perlecan Regulates Intestinal Stem Cell Activity via Cell-Matrix Attachment

    PubMed Central

    You, Jia; Zhang, Yan; Li, Zhouhua; Lou, Zhefeng; Jin, Longjin; Lin, Xinhua

    2014-01-01

    Summary Stem cells require specialized local microenvironments, termed niches, for normal retention, proliferation, and multipotency. Niches are composed of cells together with their associated extracellular matrix (ECM). Currently, the roles of ECM in regulating niche functions are poorly understood. Here, we demonstrate that Perlecan (Pcan), a highly conserved ECM component, controls intestinal stem cell (ISC) activities and ISC-ECM attachment in Drosophila adult posterior midgut. Loss of Pcan from ISCs, but not other surrounding cells, causes ISCs to detach from underlying ECM, lose their identity, and fail to proliferate. These defects are not a result of a loss of epidermal growth factor receptor (EGFR) or Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling activity but partially depend on integrin signaling activity. We propose that Pcan secreted by ISCs confers niche properties to the adjacent ECM that is required for ISC maintenance of stem cell identity, activity, and anchorage to the niche. PMID:24936464

  17. Targeting interlukin-6 to relieve immunosuppression in tumor microenvironment.

    PubMed

    Liu, Qian; Yu, Shengnan; Li, Anping; Xu, Hanxiao; Han, Xinwei; Wu, Kongming

    2017-06-01

    Immunotolerance is one of the hallmarks of malignant tumors. Tumor cells escape from host immune surveillance through various mechanisms resulting in tumor progression and therapeutic resistance. Interlukin-6 is a proinflammatory cytokine involved in many physiological and pathological processes by integrating with multiple intracellular signaling pathways. Aberrant expression of interlukin-6 is associated with the growth, metastasis, and chemotherapeutic resistance in a wide range of cancers. Interlukin-6 exerts immunosuppressive capacity mostly by stimulating the infiltrations of myeloid-derived suppressor cells, tumor-associated neutrophils, and cancer stem-like cells via Janus-activated kinase/signal transducer and activator of transcription 3 pathway in tumor microenvironment. On this foundation, blockage of interlukin-6 signal may provide potential approaches to novel therapies. In this review, we introduced interlukin-6 pathways and summarized molecular mechanisms related to interlukin-6-induced immunosuppression of tumor cell. We also concluded recent clinical studies targeting interlukin-6 as an immune-based therapeutic intervention in patients with cancer.

  18. Calcium-Oxidant Signaling Network Regulates AMP-activated Protein Kinase (AMPK) Activation upon Matrix Deprivation*

    PubMed Central

    Sundararaman, Ananthalakshmy; Amirtham, Usha; Rangarajan, Annapoorni

    2016-01-01

    The AMP-activated protein kinase (AMPK) has recently been implicated in anoikis resistance. However, the molecular mechanisms that activate AMPK upon matrix detachment remain unexplored. In this study, we show that AMPK activation is a rapid and sustained phenomenon upon matrix deprivation, whereas re-attachment to the matrix leads to its dephosphorylation and inactivation. Because matrix detachment leads to loss of integrin signaling, we investigated whether integrin signaling negatively regulates AMPK activation. However, modulation of focal adhesion kinase or Src, the major downstream components of integrin signaling, failed to cause a corresponding change in AMPK signaling. Further investigations revealed that the upstream AMPK kinases liver kinase B1 (LKB1) and Ca2+/calmodulin-dependent protein kinase kinase β (CaMKKβ) contribute to AMPK activation upon detachment. In LKB1-deficient cells, we found AMPK activation to be predominantly dependent on CaMKKβ. We observed no change in ATP levels under detached conditions at early time points suggesting that rapid AMPK activation upon detachment was not triggered by energy stress. We demonstrate that matrix deprivation leads to a spike in intracellular calcium as well as oxidant signaling, and both these intracellular messengers contribute to rapid AMPK activation upon detachment. We further show that endoplasmic reticulum calcium release-induced store-operated calcium entry contributes to intracellular calcium increase, leading to reactive oxygen species production, and AMPK activation. We additionally show that the LKB1/CaMKK-AMPK axis and intracellular calcium levels play a critical role in anchorage-independent cancer sphere formation. Thus, the Ca2+/reactive oxygen species-triggered LKB1/CaMKK-AMPK signaling cascade may provide a quick, adaptable switch to promote survival of metastasizing cancer cells. PMID:27226623

  19. An alternative mode of CD43 signal transduction activates pro-survival pathways of T lymphocytes.

    PubMed

    Bravo-Adame, Maria Elena; Vera-Estrella, Rosario; Barkla, Bronwyn J; Martínez-Campos, Cecilia; Flores-Alcantar, Angel; Ocelotl-Oviedo, Jose Pablo; Pedraza-Alva, Gustavo; Rosenstein, Yvonne

    2017-01-01

    CD43 is one of the most abundant co-stimulatory molecules on a T-cell surface; it transduces activation signals through its cytoplasmic domain, contributing to modulation of the outcome of T-cell responses. The aim of this study was to uncover new signalling pathways regulated by this sialomucin. Analysis of changes in protein abundance allowed us to identify pyruvate kinase isozyme M2 (PKM2), an enzyme of the glycolytic pathway, as an element potentially participating in the signalling cascade resulting from the engagement of CD43 and the T-cell receptor (TCR). We found that the glycolytic activity of this enzyme was not significantly increased in response to TCR+CD43 co-stimulation, but that PKM2 was tyrosine phosphorylated, suggesting that it was performing moonlight functions. We report that phosphorylation of both Y 105 of PKM2 and of Y 705 of signal transducer and activator of transcription 3 was induced in response to TCR+CD43 co-stimulation, resulting in activation of the mitogen-activated protein kinase kinase 5/extracellular signal-regulated kinase 5 (MEK5/ERK5) pathway. ERK5 and the cAMP response element binding protein (CREB) were activated, and c-Myc and nuclear factor-κB (p65) nuclear localization, as well as Bad phosphorylation, were augmented. Consistent with this, expression of human CD43 in a murine T-cell hybridoma favoured cell survival. Altogether, our data highlight novel signalling pathways for the CD43 molecule in T lymphocytes, and underscore a role for CD43 in promoting cell survival through non-glycolytic functions of metabolic enzymes. © 2016 John Wiley & Sons Ltd.

  20. Early activation of mTORC1 signalling in response to mechanical overload is independent of phosphoinositide 3-kinase/Akt signalling

    PubMed Central

    Miyazaki, Mitsunori; McCarthy, John J; Fedele, Mark J; Esser, Karyn A

    2011-01-01

    Abstract The mammalian target of rapamycin complex 1 (mTORC1) functions as a central integrator of a wide range of signals that modulate protein metabolism and cell growth. However, the contributions of individual pathways regulating mTORC1 activity in skeletal muscle are poorly defined. The purpose of this study was to determine the regulatory mechanisms that contribute to mTORC1 activation during mechanical overload-induced skeletal muscle hypertrophy. Consistent with previous studies, mechanical overload induced progressive hypertrophy of the plantaris muscle which was associated with significant increases in total RNA content and protein metabolism. mTORC1 was activated after a single day of overload as indicated by a significant increase in S6K1 phosphorylation at T389 and T421/S424. In contrast, Akt activity, as assessed by Akt phosphorylation status (T308 and S473), phosphorylation of direct downstream targets (glycogen synthase kinase 3 β, proline-rich Akt substrate 40 kDa and tuberous sclerosis 2 (TSC2)) and a kinase assay, was not significantly increased until 2–3 days of overload. Inhibition of phosphoinositide 3-kinase (PI3K) activity by wortmannin was sufficient to block insulin-dependent signalling but did not prevent the early activation of mTORC1 in response to overload. We identified that the mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK)-dependent pathway was activated at day 1 after overload. In addition, a target of MEK/ERK signalling, phosphorylation of TSC2 at S664, was also increased at this early time point. These observations demonstrate that in vivo, mTORC1 activation at the early phase of mechanical overload in skeletal muscle occurs independently of PI3K/Akt signalling and provide evidence that the MEK/ERK pathway may contribute to mTORC1 activation through phosphorylation of TSC2. PMID:21300751

  1. Mitogen-activated protein kinase phosphatase-1: a critical phosphatase manipulating mitogen-activated protein kinase signaling in cardiovascular disease (review).

    PubMed

    Li, Chang-Yi; Yang, Ling-Chao; Guo, Kai; Wang, Yue-Peng; Li, Yi-Gang

    2015-04-01

    Mitogen-activated protein kinase (MAPK) cascades are important players in the overall representation of cellular signal transduction pathways, and the deregulation of MAPKs is involved in a variety of diseases. The activation of MAPK signals occurs through phosphorylation by MAPK kinases at conserved threonine and tyrosine (Thr-Xaa-Tyr) residues. The mitogen-activated protein kinase phosphatases (MKPs) are a major part of the dual-specificity family of phosphatases and specifically inactivate MAPKs by dephosphorylating both phosphotyrosine and phosphoserine/phosphothreonine residues within the one substrate. MAPKs binding to MKPs can enhance MKP stability and activity, providing an important negative-feedback control mechanism that limits the MAPK cascades. In recent years, accumulating and compelling evidence from studies mainly employing cultured cells and mouse models has suggested that the archetypal MKP family member, MKP-1, plays a pivotal role in cardiovascular disease as a major negative modulator of MAPK signaling pathways. In the present review, we summarize the current knowledge on the pathological properties and the regulation of MKP-1 in cardiovascular disease, which may provide valuable therapeutic options.

  2. Wideband Single Crystal Transducer for Bone Characterization

    NASA Technical Reports Server (NTRS)

    Sahul, Raffi

    2015-01-01

    Phase II objectives: Optimize the Phase I transducer for sensitivity; Test different transmit signals for optimum performance; Demonstrate compatibility with electronics; Confirm additional transducer capabilities over conventional systems by calibrating with other methods.

  3. Janus nanoparticles for stable microemulsions with ultra-low IFT values

    NASA Astrophysics Data System (ADS)

    Nava, Ilse; Diaz, Agustin; Yu, Yi-Hsien; Cheng, Zhengdong

    2015-03-01

    Janus particles are an influential type of materials used in foams, detergents, surfactants and cosmetics. Due to their demonstrated flexibility and non-toxicity, they have the potential to replace molecular surfactants, and thanks to their amphiphilicity, they can stabilize immiscible biphasic systems. Disk-based Janus particles best perform this stabilization. Graphene has been used to manufacture this class of particles; however, their fabrication in high yield by short and atomically economic syntheses remains a challenge. In this project we report the first synthesis of monolayer disks by a one pot reaction under microwave energy. Using a scalable method, these disks were synthesized, emulsified (in an oil/water system), and chemically reacted to obtain the Janus nanodisks with an efficient method. Our nanosheets production technique is a promising approach for the fabrication of Janus nanodisks via emulsification as it produces IFT (interfacial tension) values in a lower range than that of the molecular surfactants. These ultra-low values, in conjunction with the sheets' salt resistance, temperature resistance, and non-toxicity position Janus particles as the next generation of nanosurfactants.

  4. Laser-structured Janus wire mesh for efficient oil-water separation.

    PubMed

    Liu, Yu-Qing; Han, Dong-Dong; Jiao, Zhi-Zhen; Liu, Yan; Jiang, Hao-Bo; Wu, Xuan-Hang; Ding, Hong; Zhang, Yong-Lai; Sun, Hong-Bo

    2017-11-23

    We report here the fabrication of a Janus wire mesh by a combined process of laser structuring and fluorosilane/graphene oxide (GO) modification of the two sides of the mesh, respectively, toward its applications in efficient oil/water separation. Femtosecond laser processing has been employed to make different laser-induced periodic surface structures (LIPSS) on each side of the mesh. Surface modification with fluorosilane on one side and GO on the other side endows the two sides of the Janus mesh with distinct wettability. Thus, one side is superhydrophobic and superoleophilic in air, and the other side is superhydrophilic in air and superoleophobic under water. As a proof of concept, we demonstrated the separation of light/heavy oil and water mixtures using this Janus mesh. To realize an efficient separation, the intrusion pressure that is dominated by the wire mesh framework and the wettability should be taken into account. Our strategy may open up a new way to design and fabricate Janus structures with distinct wettability; and the resultant Janus mesh may find broad applications in the separation of oil contaminants from water.

  5. Thermocapillary reorientation of Janus drops

    NASA Astrophysics Data System (ADS)

    Rosales, Rodolfo; Saenz, Pedro

    2017-11-01

    Janus drops, named after the Ancient Roman two-faced god, are liquid drops formed from two immiscible fluids. Experimental observations indicate that a Janus drop may re-orientate in response to an applied external thermal gradient due to the Marangoni effect. Depending on the angle between the interior interface and the direction of the temperature gradient, disparities in the physical properties of the constituent liquids may lead to asymmetries in the thermocapillary flow. As a result, the drop will move along a curved path until a torque-free configuration is achieved, point after which it will continue on a straight trajectory. Here, we present the results of a theoretical investigation of this realignment phenomenon in the Stokes regime and in the limit of non-deformable interfaces. A 3D semi-analytical method in terms of polar spherical harmonics is developed to characterize and rationalize the hydrodynamic response (forces and torques), flow (velocity and temperature distribution) and trajectory of a Janus drop moving during the temperature-driven reorientation process. Furthermore, we discuss how this phenomenon may be exploited to develop dynamically reconfigurable micro-lenses. This work was partially supported by the US National Science Foundation through Grants DMS-1614043 and DMS-1719637.

  6. Mechanisms of extracellular signal-regulated kinase/cAMP response element-binding protein/brain-derived neurotrophic factor signal transduction pathway in depressive disorder☆

    PubMed Central

    Wang, Hongyan; Zhang, Yingquan; Qiao, Mingqi

    2013-01-01

    The extracellular signal-regulated kinase/cAMP response element-binding protein/brain-derived neurotrophic factor signal transduction pathway plays an important role in the mechanism of action of antidepressant drugs and has dominated recent studies on the pathogenesis of depression. In the present review we summarize the known roles of extracellular signal-regulated kinase, cAMP response element-binding protein and brain-derived neurotrophic factor in the pathogenesis of depression and in the mechanism of action of antidepressant medicines. The extracellular signal-regulated kinase/cAMP response element-binding protein/brain-derived neurotrophic factor pathway has potential to be used as a biological index to help diagnose depression, and as such it is considered as an important new target in the treatment of depression. PMID:25206732

  7. Novel mutations and their functional and clinical relevance in myeloproliferative neoplasms: JAK2, MPL, TET2, ASXL1, CBL, IDH and IKZF1

    PubMed Central

    Tefferi, A

    2010-01-01

    Myeloproliferative neoplasms (MPNs) originate from genetically transformed hematopoietic stem cells that retain the capacity for multilineage differentiation and effective myelopoiesis. Beginning in early 2005, a number of novel mutations involving Janus kinase 2 (JAK2), Myeloproliferative Leukemia Virus (MPL), TET oncogene family member 2 (TET2), Additional Sex Combs-Like 1 (ASXL1), Casitas B-lineage lymphoma proto-oncogene (CBL), Isocitrate dehydrogenase (IDH) and IKAROS family zinc finger 1 (IKZF1) have been described in BCR-ABL1-negative MPNs. However, none of these mutations were MPN specific, displayed mutual exclusivity or could be traced back to a common ancestral clone. JAK2 and MPL mutations appear to exert a phenotype-modifying effect and are distinctly associated with polycythemia vera, essential thrombocythemia and primary myelofibrosis; the corresponding mutational frequencies are ∼99, 55 and 65% for JAK2 and 0, 3 and 10% for MPL mutations. The incidence of TET2, ASXL1, CBL, IDH or IKZF1 mutations in these disorders ranges from 0 to 17% these latter mutations are more common in chronic (TET2, ASXL1, CBL) or juvenile (CBL) myelomonocytic leukemias, mastocytosis (TET2), myelodysplastic syndromes (TET2, ASXL1) and secondary acute myeloid leukemia, including blast-phase MPN (IDH, ASXL1, IKZF1). The functional consequences of MPN-associated mutations include unregulated JAK-STAT (Janus kinase/signal transducer and activator of transcription) signaling, epigenetic modulation of transcription and abnormal accumulation of oncoproteins. However, it is not clear as to whether and how these abnormalities contribute to disease initiation, clonal evolution or blastic transformation. PMID:20428194

  8. Emerging roles of protein kinase CK2 in abscisic acid signaling.

    PubMed

    Vilela, Belmiro; Pagès, Montserrat; Riera, Marta

    2015-01-01

    The phytohormone abscisic acid (ABA) regulates many aspects of plant growth and development as well as responses to multiple stresses. Post-translational modifications such as phosphorylation or ubiquitination have pivotal roles in the regulation of ABA signaling. In addition to the positive regulator sucrose non-fermenting-1 related protein kinase 2 (SnRK2), the relevance of the role of other protein kinases, such as CK2, has been recently highlighted. We have recently established that CK2 phosphorylates the maize ortholog of open stomata 1 OST1, ZmOST1, suggesting a role of CK2 phosphorylation in the control of ZmOST1 protein degradation (Vilela et al., 2015). CK2 is a pleiotropic enzyme involved in multiple developmental and stress-responsive pathways. This review summarizes recent advances that taken together suggest a prominent role of protein kinase CK2 in ABA signaling and related processes.

  9. Receptor-like kinases as surface regulators for RAC/ROP-mediated pollen tube growth and interaction with the pistil

    PubMed Central

    Zou, Yanjiao; Aggarwal, Mini; Zheng, Wen-Guang; Wu, Hen-Ming; Cheung, Alice Y.

    2011-01-01

    Background RAC/ROPs are RHO-type GTPases and are known to play diverse signalling roles in plants. Cytoplasmic RAC/ROPs are recruited to the cell membrane and activated in response to extracellular signals perceived and mediated by cell surface-located signalling assemblies, transducing the signals to regulate cellular processes. More than any other cell types in plants, pollen tubes depend on continuous interactions with an extracellular environment produced by their surrounding tissues as they grow within the female organ pistil to deliver sperm to the female gametophyte for fertilization. Scope We review studies on pollen tube growth that provide compelling evidence indicating that RAC/ROPs are crucial for regulating the cellular processes that underlie the polarized cell growth process. Efforts to identify cell surface regulators that mediate extracellular signals also point to RAC/ROPs being the molecular switches targeted by growth-regulating female factors for modulation to mediate pollination and fertilization. We discuss a large volume of work spanning more than two decades on a family of pollen-specific receptor kinases and some recent studies on members of the FERONIA family of receptor-like kinases (RLKs). Significance The research described shows the crucial roles that two RLK families play in transducing signals from growth regulatory factors to the RAC/ROP switch at the pollen tube apex to mediate and target pollen tube growth to the female gametophyte and signal its disintegration to achieve fertilization once inside the female chamber. PMID:22476487

  10. Control of vascular smooth muscle function by Src-family kinases and reactive oxygen species in health and disease

    PubMed Central

    MacKay, Charles E; Knock, Greg A

    2015-01-01

    Abstract Reactive oxygen species (ROS) are now recognised as second messenger molecules that regulate cellular function by reversibly oxidising specific amino acid residues of key target proteins. Amongst these are the Src-family kinases (SrcFKs), a multi-functional group of non-receptor tyrosine kinases highly expressed in vascular smooth muscle (VSM). In this review we examine the evidence supporting a role for ROS-induced SrcFK activity in normal VSM contractile function and in vascular remodelling in cardiovascular disease. VSM contractile responses to G-protein-coupled receptor stimulation, as well as hypoxia in pulmonary artery, are shown to be dependent on both ROS and SrcFK activity. Specific phosphorylation targets are identified amongst those that alter intracellular Ca2+ concentration, including transient receptor potential channels, voltage-gated Ca2+ channels and various types of K+ channels, as well as amongst those that regulate actin cytoskeleton dynamics and myosin phosphatase activity, including focal adhesion kinase, protein tyrosine kinase-2, Janus kinase, other focal adhesion-associated proteins, and Rho guanine nucleotide exchange factors. We also examine a growing weight of evidence in favour of a key role for SrcFKs in multiple pro-proliferative and anti-apoptotic signalling pathways relating to oxidative stress and vascular remodelling, with a particular focus on pulmonary hypertension, including growth-factor receptor transactivation and downstream signalling, hypoxia-inducible factors, positive feedback between SrcFK and STAT3 signalling and positive feedback between SrcFK and NADPH oxidase dependent ROS production. We also discuss evidence for and against the potential therapeutic targeting of SrcFKs in the treatment of pulmonary hypertension. PMID:25384773

  11. JANUS: a bit-wise reversible integrator for N-body dynamics

    NASA Astrophysics Data System (ADS)

    Rein, Hanno; Tamayo, Daniel

    2018-01-01

    Hamiltonian systems such as the gravitational N-body problem have time-reversal symmetry. However, all numerical N-body integration schemes, including symplectic ones, respect this property only approximately. In this paper, we present the new N-body integrator JANUS , for which we achieve exact time-reversal symmetry by combining integer and floating point arithmetic. JANUS is explicit, formally symplectic and satisfies Liouville's theorem exactly. Its order is even and can be adjusted between two and ten. We discuss the implementation of JANUS and present tests of its accuracy and speed by performing and analysing long-term integrations of the Solar system. We show that JANUS is fast and accurate enough to tackle a broad class of dynamical problems. We also discuss the practical and philosophical implications of running exactly time-reversible simulations.

  12. Agonistic and Antagonistic Roles for TNIK and MINK in Non-Canonical and Canonical Wnt Signalling

    PubMed Central

    Mikryukov, Alexander; Moss, Tom

    2012-01-01

    Wnt signalling is a key regulatory factor in animal development and homeostasis and plays an important role in the establishment and progression of cancer. Wnt signals are predominantly transduced via the Frizzled family of serpentine receptors to two distinct pathways, the canonical ß-catenin pathway and a non-canonical pathway controlling planar cell polarity and convergent extension. Interference between these pathways is an important determinant of cellular and phenotypic responses, but is poorly understood. Here we show that TNIK (Traf2 and Nck-interacting kinase) and MINK (Misshapen/NIKs-related kinase) MAP4K signalling kinases are integral components of both canonical and non-canonical pathways in Xenopus. xTNIK and xMINK interact and are proteolytically cleaved in vivo to generate Kinase domain fragments that are active in signal transduction, and Citron-NIK-Homology (CNH) Domain fragments that are suppressive. The catalytic activity of the Kinase domain fragments of both xTNIK and xMINK mediate non-canonical signalling. However, while the Kinase domain fragments of xTNIK also mediate canonical signalling, the analogous fragments derived from xMINK strongly antagonize this signalling. Our data suggest that the proteolytic cleavage of xTNIK and xMINK determines their respective activities and is an important factor in controlling the balance between canonical and non-canonical Wnt signalling in vivo. PMID:22984420

  13. Study of Aggregation of Janus Ellipsoids

    NASA Astrophysics Data System (ADS)

    Ruth, Donovan; Li, Wei; Khadka, Shreeya; Rickman, Jeffrey; Gunton, James

    2013-03-01

    We perform numerical simulations of a quasi-square well potential model of one-patch colloidal particles to investigate the collective structure of a system of Janus ellipsoids. We show that for Janus ellipsoids such that one half is an attractive patch, while the entire ellipsoid has a hardcore repulsion, the system organizes into a distribution of orientationally ordered micelles and vesicles. We analyze the cluster distribution at several temperatures and low densities and show that below certain temperatures the system is populated by stable clusters and depending on temperature and density the system is populated by either vesicles or micelle structures.

  14. Erythropoietin activates telomerase through transcriptional and posttranscriptional regulation in human erythroleukemic JAS-REN-A cells.

    PubMed

    Akiyama, Masaharu; Kawano, Takeshi; Mikami-Terao, Yoko; Agawa-Ohta, Miyuki; Yamada, Osamu; Ida, Hiroyuki; Yamada, Hisashi

    2011-03-01

    We evaluated the molecular mechanism of telomerase activation by erythropoietin (EPO) in human erythroleukemic JAS-REN-A cells. Telomerase activity increased 3-4 fold after 3-24h of culture with EPO and was associated with increases in c-myc mRNA after 1-3h, of c-Myc protein after 3-6h, and of human telomerase reverse transcriptase (hTERT) mRNA and hTERT protein after 6-24h. Simultaneously EPO induced phosphorylation of signal transducer activator of transcription 5 (STAT5), AKT, and extracellular signal-regulated kinase (ERK). Telomerase activity induced by EPO was significantly inhibited by AG490, PD98059, and LY294002. AG490 downregulated c-myc and hTERT mRNA expression with inhibited STAT5 and AKT phosphorylation. PD98059 also reduced c-myc and hTERT expression and inhibited ERK phosphorylation. However, LY294002 did not inhibit c-myc or hTERT mRNA expression despite inhibiting STAT5 and AKT phosphorylation. These results suggest that EPO activates telomerase in JAS-REN-A cells through dual regulation: hTERT gene transcription by Janus tyrosine kinase 2/STAT5/c-Myc and hTERT protein phosphorylation by phosphatidylinositol 3'-kinase/AKT. Copyright © 2010 Elsevier Ltd. All rights reserved.

  15. Dynamic Janus Metasurfaces in the Visible Spectral Region.

    PubMed

    Yu, Ping; Li, Jianxiong; Zhang, Shuang; Jin, Zhongwei; Schütz, Gisela; Qiu, Cheng-Wei; Hirscher, Michael; Liu, Na

    2018-06-27

    Janus monolayers have long been captivated as a popular notion for breaking in-plane and out-of-plane structural symmetry. Originated from chemistry and materials science, the concept of Janus functions have been recently extended to ultrathin metasurfaces by arranging meta-atoms asymmetrically with respect to the propagation or polarization direction of the incident light. However, such metasurfaces are intrinsically static and the information they carry can be straightforwardly decrypted by scanning the incident light directions and polarization states once the devices are fabricated. In this Letter, we present a dynamic Janus metasurface scheme in the visible spectral region. In each super unit cell, three plasmonic pixels are categorized into two sets. One set contains a magnesium nanorod and a gold nanorod that are orthogonally oriented with respect to each other, working as counter pixels. The other set only contains a magnesium nanorod. The effective pixels on the Janus metasurface can be reversibly regulated by hydrogenation/dehydrogenation of the magnesium nanorods. Such dynamic controllability at visible frequencies allows for flat optical elements with novel functionalities including beam steering, bifocal lensing, holographic encryption, and dual optical function switching.

  16. ESCMID Study Group for Infections in Compromised Hosts (ESGICH) Consensus Document on the safety of targeted and biological therapies: an infectious diseases perspective (Intracellular signaling pathways: tyrosine kinase and mTOR inhibitors).

    PubMed

    Reinwald, M; Silva, J T; Mueller, N J; Fortún, J; Garzoni, C; de Fijter, J W; Fernández-Ruiz, M; Grossi, P; Aguado, J M

    2018-06-01

    The present review is part of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Infections in Compromised Hosts (ESGICH) Consensus Document on the safety of targeted and biologic therapies. To review, from an infectious diseases perspective, the safety profile of therapies targeting different intracellular signaling pathways and to suggest preventive recommendations. Computer-based Medline searches with MeSH terms pertaining to each agent or therapeutic family. Although BCR-ABL tyrosine kinase inhibitors modestly increase the overall risk of infection, dasatinib has been associated with cytomegalovirus and hepatitis B virus reactivation. BRAF/MEK kinase inhibitors do not significantly affect infection susceptibility. The effect of Bruton tyrosine kinase inhibitors (ibrutinib) among patients with B-cell malignancies is difficult to distinguish from that of previous immunosuppression. However, cases of Pneumocystis jirovecii pneumonia (PCP), invasive fungal infection and progressive multifocal leukoencephalopathy have been occasionally reported. Because phosphatidylinositol-3-kinase inhibitors (idelalisib) may predispose to opportunistic infections, anti-Pneumocystis prophylaxis and prevention strategies for cytomegalovirus are recommended. No increased rates of infection have been observed with venetoclax (antiapoptotic protein Bcl-2 inhibitor). Therapy with Janus kinase inhibitors markedly increases the incidence of infection. Pretreatment screening for chronic hepatitis B virus and latent tuberculosis infection must be performed, and anti-Pneumocystis prophylaxis should be considered for patients with additional risk factors. Cancer patients receiving mTOR inhibitors face an increased incidence of overall infection, especially those with additional risk factors (prior therapies or delayed wound healing). Specific preventive approaches are warranted in view of the increased risk of infection associated with some of the

  17. Mitogen-activated protein kinase kinase 5 (MKK5)-mediated signalling cascade regulates expression of iron superoxide dismutase gene in Arabidopsis under salinity stress

    PubMed Central

    Xing, Yu; Chen, Wei-hua; Jia, Wensuo; Zhang, Jianhua

    2015-01-01

    Superoxide dismutases (SODs) are involved in plant adaptive responses to biotic and abiotic stresses but the upstream signalling process that modulates their expression is not clear. Expression of two iron SODs, FSD2 and FSD3, was significantly increased in Arabidopsis in response to NaCl treatment but blocked in transgenic MKK5-RNAi plant, mkk5. Using an assay system for transient expression in protoplasts, it was found that mitogen-activated protein kinase kinase 5 (MKK5) was also activated in response to salt stress. Overexpression of MKK5 in wild-type plants enhanced their tolerance to salt treatments, while mkk5 mutant exhibited hypersensitivity to salt stress in germination on salt-containing media. Moreover, another kinase, MPK6, was also involved in the MKK5-mediated iron superoxide dismutase (FSD) signalling pathway in salt stress. The kinase activity of MPK6 was totally turned off in mkk5, whereas the activity of MPK3 was only partially blocked. MKK5 interacted with the MEKK1 protein that was also involved in the salt-induced FSD signalling pathway. These data suggest that salt-induced FSD2 and FSD3 expressions are influenced by MEKK1 via MKK5–MPK6-coupled signalling. This MAP kinase cascade (MEKK1, MKK5, and MPK6) mediates the salt-induced expression of iron superoxide dismutases. PMID:26136265

  18. Cinnamaldehyde impairs high glucose-induced hypertrophy in renal interstitial fibroblasts

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chao, Louis Kuoping; Chang, W.-T.; Shih, Y.-W.

    2010-04-15

    Cinnamaldehyde is a major and a bioactive compound isolated from the leaves of Cinnamomum osmophloeum kaneh. To explore whether cinnamaldehyde was linked to altered high glucose (HG)-mediated renal tubulointerstitial fibrosis in diabetic nephropathy (DN), the molecular mechanisms of cinnamaldehyde responsible for inhibition of HG-induced hypertrophy in renal interstitial fibroblasts were examined. We found that cinnamaldehyde caused inhibition of HG-induced cellular mitogenesis rather than cell death by either necrosis or apoptosis. There were no changes in caspase 3 activity, cleaved poly(ADP-ribose) polymerase (PARP) protein expression, and mitochondrial cytochrome c release in HG or cinnamaldehyde treatments in these cells. HG-induced extracellular signal-regulatedmore » kinase (ERK)/c-Jun N-terminal kinase (JNK)/p38 mitogen-activated protein kinase (MAPK) (but not the Janus kinase 2/signal transducers and activators of transcription) activation was markedly blocked by cinnamaldehyde. The ability of cinnamaldehyde to inhibit HG-induced hypertrophy was verified by the observation that it significantly decreased cell size, cellular hypertrophy index, and protein levels of collagen IV, fibronectin, and alpha-smooth muscle actin (alpha-SMA). The results obtained in this study suggest that cinnamaldehyde treatment of renal interstitial fibroblasts that have been stimulated by HG reduces their ability to proliferate and hypertrophy through mechanisms that may be dependent on inactivation of the ERK/JNK/p38 MAPK pathway.« less

  19. Cardiac-Specific SOCS3 Deletion Prevents In Vivo Myocardial Ischemia Reperfusion Injury through Sustained Activation of Cardioprotective Signaling Molecules.

    PubMed

    Nagata, Takanobu; Yasukawa, Hideo; Kyogoku, Sachiko; Oba, Toyoharu; Takahashi, Jinya; Nohara, Shoichiro; Minami, Tomoko; Mawatari, Kazutoshi; Sugi, Yusuke; Shimozono, Koutatsu; Pradervand, Sylvain; Hoshijima, Masahiko; Aoki, Hiroki; Fukumoto, Yoshihiro; Imaizumi, Tsutomu

    2015-01-01

    Myocardial ischemia reperfusion injury (IRI) adversely affects cardiac performance and the prognosis of patients with acute myocardial infarction. Although myocardial signal transducer and activator of transcription (STAT) 3 is potently cardioprotective during IRI, the inhibitory mechanism responsible for its activation is largely unknown. The present study aimed to investigate the role of the myocardial suppressor of cytokine signaling (SOCS)-3, an intrinsic negative feedback regulator of the Janus kinase (JAK)-STAT signaling pathway, in the development of myocardial IRI. Myocardial IRI was induced in mice by ligating the left anterior descending coronary artery for 1 h, followed by different reperfusion times. One hour after reperfusion, the rapid expression of JAK-STAT-activating cytokines was observed. We precisely evaluated the phosphorylation of cardioprotective signaling molecules and the expression of SOCS3 during IRI and then induced myocardial IRI in wild-type and cardiac-specific SOCS3 knockout mice (SOCS3-CKO). The activation of STAT3, AKT, and ERK1/2 rapidly peaked and promptly decreased during IRI. This decrease correlated with the induction of SOCS3 expression up to 24 h after IRI in wild-type mice. The infarct size 24 h after reperfusion was significantly reduced in SOCS3-CKO compared with wild-type mice. In SOCS3-CKO mice, STAT3, AKT, and ERK1/2 phosphorylation was sustained, myocardial apoptosis was prevented, and the expression of anti-apoptotic Bcl-2 family member myeloid cell leukemia-1 (Mcl-1) was augmented. Cardiac-specific SOCS3 deletion led to the sustained activation of cardioprotective signaling molecules including and prevented myocardial apoptosis and injury during IRI. Our findings suggest that SOCS3 may represent a key factor that exacerbates the development of myocardial IRI.

  20. Cardiac-Specific SOCS3 Deletion Prevents In Vivo Myocardial Ischemia Reperfusion Injury through Sustained Activation of Cardioprotective Signaling Molecules

    PubMed Central

    Nagata, Takanobu; Yasukawa, Hideo; Kyogoku, Sachiko; Oba, Toyoharu; Takahashi, Jinya; Nohara, Shoichiro; Minami, Tomoko; Mawatari, Kazutoshi; Sugi, Yusuke; Shimozono, Koutatsu; Pradervand, Sylvain; Hoshijima, Masahiko; Aoki, Hiroki; Fukumoto, Yoshihiro; Imaizumi, Tsutomu

    2015-01-01

    Myocardial ischemia reperfusion injury (IRI) adversely affects cardiac performance and the prognosis of patients with acute myocardial infarction. Although myocardial signal transducer and activator of transcription (STAT) 3 is potently cardioprotective during IRI, the inhibitory mechanism responsible for its activation is largely unknown. The present study aimed to investigate the role of the myocardial suppressor of cytokine signaling (SOCS)-3, an intrinsic negative feedback regulator of the Janus kinase (JAK)-STAT signaling pathway, in the development of myocardial IRI. Myocardial IRI was induced in mice by ligating the left anterior descending coronary artery for 1 h, followed by different reperfusion times. One hour after reperfusion, the rapid expression of JAK-STAT–activating cytokines was observed. We precisely evaluated the phosphorylation of cardioprotective signaling molecules and the expression of SOCS3 during IRI and then induced myocardial IRI in wild-type and cardiac-specific SOCS3 knockout mice (SOCS3-CKO). The activation of STAT3, AKT, and ERK1/2 rapidly peaked and promptly decreased during IRI. This decrease correlated with the induction of SOCS3 expression up to 24 h after IRI in wild-type mice. The infarct size 24 h after reperfusion was significantly reduced in SOCS3-CKO compared with wild-type mice. In SOCS3-CKO mice, STAT3, AKT, and ERK1/2 phosphorylation was sustained, myocardial apoptosis was prevented, and the expression of anti-apoptotic Bcl-2 family member myeloid cell leukemia-1 (Mcl-1) was augmented. Cardiac-specific SOCS3 deletion led to the sustained activation of cardioprotective signaling molecules including and prevented myocardial apoptosis and injury during IRI. Our findings suggest that SOCS3 may represent a key factor that exacerbates the development of myocardial IRI. PMID:26010537

  1. Bilinear Time-frequency Analysis for Lamb Wave Signal Detected by Electromagnetic Acoustic Transducer

    NASA Astrophysics Data System (ADS)

    Sun, Wenxiu; Liu, Guoqiang; Xia, Hui; Xia, Zhengwu

    2018-03-01

    Accurate acquisition of the detection signal travel time plays a very important role in cross-hole tomography. The experimental platform of aluminum plate under the perpendicular magnetic field is established and the bilinear time-frequency analysis methods, Wigner-Ville Distribution (WVD) and the pseudo-Wigner-Ville distribution (PWVD), are applied to analyse the Lamb wave signals detected by electromagnetic acoustic transducer (EMAT). By extracting the same frequency component of the time-frequency spectrum as the excitation frequency, the travel time information can be obtained. In comparison with traditional linear time-frequency analysis method such as short-time Fourier transform (STFT), the bilinear time-frequency analysis method PWVD is more appropriate in extracting travel time and recognizing patterns of Lamb wave.

  2. Highly Efficient Light-Driven TiO2-Au Janus Micromotors.

    PubMed

    Dong, Renfeng; Zhang, Qilu; Gao, Wei; Pei, Allen; Ren, Biye

    2016-01-26

    A highly efficient light-driven photocatalytic TiO2-Au Janus micromotor with wireless steering and velocity control is described. Unlike chemically propelled micromotors which commonly require the addition of surfactants or toxic chemical fuels, the fuel-free Janus micromotor (diameter ∼1.0 μm) can be powered in pure water under an extremely low ultraviolet light intensity (2.5 × 10(-3) W/cm(2)), and with 40 × 10(-3) W/cm(2), they can reach a high speed of 25 body length/s, which is comparable to common Pt-based chemically induced self-electrophoretic Janus micromotors. The photocatalytic propulsion can be switched on and off by incident light modulation. In addition, the speed of the photocatalytic TiO2-Au Janus micromotor can be accelerated by increasing the light intensity or by adding low concentrations of chemical fuel H2O2 (i.e., 0.1%). The attractive fuel-free propulsion performance, fast movement triggering response, low light energy requirement, and precise motion control of the TiO2-Au Janus photocatalytic micromotor hold considerable promise for diverse practical applications.

  3. The Antiviral Alkaloid Berberine Reduces Chikungunya Virus-Induced Mitogen-Activated Protein Kinase Signaling

    PubMed Central

    Thaa, Bastian; Amrun, Siti Naqiah; Simarmata, Diane; Rausalu, Kai; Nyman, Tuula A.; Merits, Andres; McInerney, Gerald M.; Ng, Lisa F. P.

    2016-01-01

    ABSTRACT Chikungunya virus (CHIKV) has infected millions of people in the tropical and subtropical regions since its reemergence in the last decade. We recently identified the nontoxic plant alkaloid berberine as an antiviral substance against CHIKV in a high-throughput screen. Here, we show that berberine is effective in multiple cell types against a variety of CHIKV strains, also at a high multiplicity of infection, consolidating the potential of berberine as an antiviral drug. We excluded any effect of this compound on virus entry or on the activity of the viral replicase. A human phosphokinase array revealed that CHIKV infection specifically activated the major mitogen-activated protein kinase (MAPK) signaling pathways extracellular signal-related kinase (ERK), p38 and c-Jun NH2-terminal kinase (JNK). Upon treatment with berberine, this virus-induced MAPK activation was markedly reduced. Subsequent analyses with specific inhibitors of these kinases indicated that the ERK and JNK signaling cascades are important for the generation of progeny virions. In contrast to specific MAPK inhibitors, berberine lowered virus-induced activation of all major MAPK pathways and resulted in a stronger reduction in viral titers. Further, we assessed the in vivo efficacy of berberine in a mouse model and measured a significant reduction of CHIKV-induced inflammatory disease. In summary, we demonstrate the efficacy of berberine as a drug against CHIKV and highlight the importance of the MAPK signaling pathways in the alphavirus infectious cycle. IMPORTANCE Chikungunya virus (CHIKV) is a mosquito-borne virus that causes severe and persistent muscle and joint pain and has recently spread to the Americas. No licensed drug exists to counter this virus. In this study, we report that the alkaloid berberine is antiviral against different CHIKV strains and in multiple human cell lines. We demonstrate that berberine collectively reduced the virus-induced activation of cellular mitogen

  4. STATs in cancer inflammation and immunity: a leading role for STAT3.

    PubMed

    Yu, Hua; Pardoll, Drew; Jove, Richard

    2009-11-01

    Commensurate with their roles in regulating cytokine-dependent inflammation and immunity, signal transducer and activator of transcription (STAT) proteins are central in determining whether immune responses in the tumour microenvironment promote or inhibit cancer. Persistently activated STAT3 and, to some extent, STAT5 increase tumour cell proliferation, survival and invasion while suppressing anti-tumour immunity. The persistent activation of STAT3 also mediates tumour-promoting inflammation. STAT3 has this dual role in tumour inflammation and immunity by promoting pro-oncogenic inflammatory pathways, including nuclear factor-kappaB (NF-kappaB) and interleukin-6 (IL-6)-GP130-Janus kinase (JAK) pathways, and by opposing STAT1- and NF-kappaB-mediated T helper 1 anti-tumour immune responses. Consequently, STAT3 is a promising target to redirect inflammation for cancer therapy.

  5. Systematic screen of chemotherapeutics in Drosophila stem cell tumors

    PubMed Central

    Markstein, Michele; Dettorre, Samantha; Cho, Julio; Neumüller, Ralph A.; Craig-Müller, Sören; Perrimon, Norbert

    2014-01-01

    Here we report the development of an in vivo system to study the interaction of stem cells with drugs using a tumor model in the adult Drosophila intestine. Strikingly, we find that some Food and Drug Administration-approved chemotherapeutics that can inhibit the growth of Drosophila tumor stem cells can paradoxically promote the hyperproliferation of their wild-type counterparts. These results reveal an unanticipated side effect on stem cells that may contribute to tumor recurrence. We propose that the same side effect may occur in humans based on our finding that it is driven in Drosophila by the evolutionarily conserved Janus kinase-signal transducers and activators of transcription (JAK-STAT) pathway. An immediate implication of our findings is that supplementing traditional chemotherapeutics with anti-inflammatories may reduce tumor recurrence. PMID:24616500

  6. Acoustooptic pulse-echo transducer system

    NASA Technical Reports Server (NTRS)

    Claus, R. O.; Wade, J. C.

    1983-01-01

    A pulse-echo transducer system which uses an ultrasonic generating element and an optical detection technique is described. The transmitting transducer consists of a concentric ring electrode pattern deposited on a circular, X-cut quartz substrate with a circular hole in the center. The rings are independently pulsed with a sequence high voltage signals phased in such a way that the ultrasonic waves generated by the separate rings superimpose to produce a composite field which is focused at a controllable distance below the surface of the specimen. The amplitude of the field reflected from this focus position is determined by the local reflection coefficient of the medium at the effective focal point. By processing the signals received for a range of ultrasonic transducer array focal lengths, the system can be used to locate and size anomalies within solids and liquids. Applications in both nondestructive evaluation and biomedical scanning are suggested.

  7. Wideband Single-Crystal Transducer for Bone Characterization

    NASA Technical Reports Server (NTRS)

    Liang, Yu; Snook, Kevin

    2012-01-01

    The microgravity conditions of space travel result in unique physiological demands on the human body. In particular, the absence of the continual mechanical stresses on the skeletal system that are present on Earth cause the bones to decalcify. Trabecular structure decreases in thickness and increases in spacing, resulting in decreased bone strength and increased risk of injury. Thus, monitoring bone health is a high priority for long-term space travel. A single probe covering all frequency bands of interest would be ideal for such measurements, and this would also minimize storage space and eliminate the complexity of integrating multiple probes. This invention is an ultrasound transducer for the structural characterization of bone. Such characterization measures features of reflected and transmitted ultrasound signals, and correlates these signals with bone structure metrics such as bone mineral density, trabecular spacing, and thickness, etc. The techniques used to determine these various metrics require measurements over a broad range of ultrasound frequencies, and therefore, complete characterization requires the use of several narrowband transducers. This is a single transducer capable of making these measurements in all the required frequency bands. The device achieves this capability through a unique combination of a broadband piezoelectric material; a design incorporating multiple resonator sizes with distinct, overlapping frequency spectra; and a micromachining process for producing the multiple-resonator pattern with common electrode surfaces between the resonators. This device consists of a pattern of resonator bars with common electrodes that is wrapped around a central mandrel such that the radiating faces of the resonators are coplanar and can be simultaneously applied to the sample to be measured. The device operates as both a source and receiver of acoustic energy. It is operated by connection to an electronic system capable of both providing an

  8. Aggression behaviour induced by oral administration of the Janus-kinase inhibitor tofacitinib, but not oclacitinib, under stressful conditions.

    PubMed

    Fukuyama, Tomoki; Tschernig, Thomas; Qi, Yulin; Volmer, Dietrich A; Bäumer, Wolfgang

    2015-10-05

    Janus kinase (JAK) inhibitors have recently been developed for allergic diseases. We focused on the 2 different JAK inhibitors, tofacitinib (selective for JAK3) and oclacitinib (selective for JAK1 and 2), to clarify the mechanism of anti-inflammatory and anti-itching potency of these drugs. In the process of detecting anti-itching potency, we observed that tofacitinib treated mice showed aggression behaviour. The objective of the study reported here was to investigate the aggressive behaviour induced by tofacitinib by using a mouse model of allergic dermatitis and the resident-intruder test. For the allergic dermatitis model, female BALB/c mice were sensitised and challenged topically with toluene-2,4-diisocyanate (TDI). Vehicle, tofacitinib or oclacitinib, was administered orally 30 min before TDI challenge. Scratching, aggression and standing behaviours were monitored in the 60 min period immediately following challenge of TDI. Another group of male BALB/c mice treated with vehicle, tofacitinib or oclacitinib was evaluated in the resident-intruder test and brains were obtained to determine blood brain barrier penetration. In the allergic dermatitis model, a significant increase in aggression and standing behaviour was only obvious in the tofacitinib treatment group. There was no effect in non-sensitised mice, but similar aggression was also induced by tofacitinib in male resident-intruder test. Penetration of blood-brain barrier was observed both in tofacitinib and oclacitinib treated mice. These results suggest that aggression was induced by tofacitinib under some kind of stressful environment. This study indicates a possible role of the JAK-STAT pathway in modulation of aggression behaviour. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Linear signaling in the Toll-Dorsal pathway of Drosophila: activated Pelle kinase specifies all threshold outputs of gene expression while the bHLH protein Twist specifies a subset.

    PubMed

    Stathopoulos, Angelike; Levine, Michael

    2002-07-01

    Differential activation of the Toll receptor leads to the formation of a broad Dorsal nuclear gradient that specifies at least three patterning thresholds of gene activity along the dorsoventral axis of precellular embryos. We investigate the activities of the Pelle kinase and Twist basic helix-loop-helix (bHLH) transcription factor in transducing Toll signaling. Pelle functions downstream of Toll to release Dorsal from the Cactus inhibitor. Twist is an immediate-early gene that is activated upon entry of Dorsal into nuclei. Transgenes misexpressing Pelle and Twist were introduced into different mutant backgrounds and the patterning activities were visualized using various target genes that respond to different thresholds of Toll-Dorsal signaling. These studies suggest that an anteroposterior gradient of Pelle kinase activity is sufficient to generate all known Toll-Dorsal patterning thresholds and that Twist can function as a gradient morphogen to establish at least two distinct dorsoventral patterning thresholds. We discuss how the Dorsal gradient system can be modified during metazoan evolution and conclude that Dorsal-Twist interactions are distinct from the interplay between Bicoid and Hunchback, which pattern the anteroposterior axis.

  10. Vaccinia Virus Protein C6 Inhibits Type I IFN Signalling in the Nucleus and Binds to the Transactivation Domain of STAT2.

    PubMed

    Stuart, Jennifer H; Sumner, Rebecca P; Lu, Yongxu; Snowden, Joseph S; Smith, Geoffrey L

    2016-12-01

    The type I interferon (IFN) response is a crucial innate immune signalling pathway required for defense against viral infection. Accordingly, the great majority of mammalian viruses possess means to inhibit this important host immune response. Here we show that vaccinia virus (VACV) strain Western Reserve protein C6, is a dual function protein that inhibits the cellular response to type I IFNs in addition to its published function as an inhibitor of IRF-3 activation, thereby restricting type I IFN production from infected cells. Ectopic expression of C6 inhibits the induction of interferon stimulated genes (ISGs) in response to IFNα treatment at both the mRNA and protein level. C6 inhibits the IFNα-induced Janus kinase/signal transducer and activator of transcription (JAK/STAT) signalling pathway at a late stage, downstream of STAT1 and STAT2 phosphorylation, nuclear translocation and binding of the interferon stimulated gene factor 3 (ISGF3) complex to the interferon stimulated response element (ISRE). Mechanistically, C6 associates with the transactivation domain of STAT2 and this might explain how C6 inhibits the type I IFN signalling very late in the pathway. During virus infection C6 reduces ISRE-dependent gene expression despite the presence of the viral protein phosphatase VH1 that dephosphorylates STAT1 and STAT2. The ability of a cytoplasmic replicating virus to dampen the immune response within the nucleus, and the ability of viral immunomodulators such as C6 to inhibit multiple stages of the innate immune response by distinct mechanisms, emphasizes the intricacies of host-pathogen interactions and viral immune evasion.

  11. Src-family-tyrosine kinase Lyn is critical for TLR2-mediated NF-κB activation through the PI 3-kinase signaling pathway.

    PubMed

    Toubiana, Julie; Rossi, Anne-Lise; Belaidouni, Nadia; Grimaldi, David; Pene, Frederic; Chafey, Philippe; Comba, Béatrice; Camoin, Luc; Bismuth, Georges; Claessens, Yann-Erick; Mira, Jean-Paul; Chiche, Jean-Daniel

    2015-10-01

    TLR2 has a prominent role in host defense against a wide variety of pathogens. Stimulation of TLR2 triggers MyD88-dependent signaling to induce NF-κB translocation, and activates a Rac1-PI 3-kinase dependent pathway that leads to transactivation of NF-κB through phosphorylation of the P65 NF-κB subunit. This transactivation pathway involves tyrosine phosphorylations. The role of the tyrosine kinases in TLR signaling is controversial, with discrepancies between studies using only chemical inhibitors and knockout mice. Here, we show the involvement of the tyrosine-kinase Lyn in TLR2-dependent activation of NF-κB in human cellular models, by using complementary inhibition strategies. Stimulation of TLR2 induces the formation of an activation cluster involving TLR2, CD14, PI 3-kinase and Lyn, and leads to the activation of AKT. Lyn-dependent phosphorylation of the p110 catalytic subunit of PI 3-kinase is essential to the control of PI 3-kinase biological activity upstream of AKT and thereby to the transactivation of NF-κB. Thus, Lyn kinase activity is crucial in TLR2-mediated activation of the innate immune response in human mononuclear cells. © The Author(s) 2015.

  12. Determinants of cell-to-cell variability in protein kinase signaling.

    PubMed

    Jeschke, Matthias; Baumgärtner, Stephan; Legewie, Stefan

    2013-01-01

    Cells reliably sense environmental changes despite internal and external fluctuations, but the mechanisms underlying robustness remain unclear. We analyzed how fluctuations in signaling protein concentrations give rise to cell-to-cell variability in protein kinase signaling using analytical theory and numerical simulations. We characterized the dose-response behavior of signaling cascades by calculating the stimulus level at which a pathway responds ('pathway sensitivity') and the maximal activation level upon strong stimulation. Minimal kinase cascades with gradual dose-response behavior show strong variability, because the pathway sensitivity and the maximal activation level cannot be simultaneously invariant. Negative feedback regulation resolves this trade-off and coordinately reduces fluctuations in the pathway sensitivity and maximal activation. Feedbacks acting at different levels in the cascade control different aspects of the dose-response curve, thereby synergistically reducing the variability. We also investigated more complex, ultrasensitive signaling cascades capable of switch-like decision making, and found that these can be inherently robust to protein concentration fluctuations. We describe how the cell-to-cell variability of ultrasensitive signaling systems can be actively regulated, e.g., by altering the expression of phosphatase(s) or by feedback/feedforward loops. Our calculations reveal that slow transcriptional negative feedback loops allow for variability suppression while maintaining switch-like decision making. Taken together, we describe design principles of signaling cascades that promote robustness. Our results may explain why certain signaling cascades like the yeast pheromone pathway show switch-like decision making with little cell-to-cell variability.

  13. Janus droplet as a catalytic micromotor

    NASA Astrophysics Data System (ADS)

    Shklyaev, Sergey

    2015-06-01

    Self-propulsion of a Janus droplet in a solution of surfactant, which reacts on a half of a drop surface, is studied theoretically. The droplet acts as a catalytic motor creating a concentration gradient, which generates its surface-tension-driven motion; the self-propulsion speed is rather high, 60 μ \\text{m/s} and more. This catalytic motor has several advantages over other micromotors: simple manufacturing, easily attained neutral buoyancy. In contrast to a single-fluid droplet, which demonstrates a self-propulsion as a result of symmetry breaking instability, for the Janus one no stability threshold exists; hence, the droplet radius can be scaled down to micrometers.

  14. Defibrotide Stimulates Angiogenesis and Protects Endothelial Cells from Calcineurin Inhibitor-Induced Apoptosis via Upregulation of AKT/Bcl-xL.

    PubMed

    Wang, Xiangmin; Pan, Bin; Hashimoto, Yuko; Ohkawara, Hiroshi; Xu, Kailin; Zeng, Lingyu; Ikezoe, Takayuki

    2018-01-01

    Sinusoidal obstruction syndrome is a life-threatening complication that can occur after haematopoietic stem cell transplantation. Defibrotide (DF) has been approved for the treatment of individuals with severe sinusoidal obstruction syndrome following haematopoietic stem cell transplantation in the European Union and the United States. However, the precise mechanisms by which DF protects endothelial cells remain to be elucidated. In this study, we found that DF stimulated angiogenesis in vitro and in vivo as assessed by vascular tube formation, scratch-wound repair and Matrigel plug assays. These effects were associated with an activation of pro-survival signalling pathways, including AKT (protein kinase B), ERK (extracellular signal-regulated kinases) and p38. More importantly, DF alleviated calcineurin inhibitor-induced growth inhibition and apoptosis of human umbilical vein endothelial cells and human hepatic sinusoidal endothelial cells in parallel with upregulation of anti-apoptotic protein B-cell lymphoma-extra-large (Bcl-xL), which was mediated by AKT (protein kinase B). Notably, these effects were abrogated when Bcl-xL was depleted by small interfering RNA (ribonucleic acid). In addition, DF counteracted calcineurin inhibitor-induced activation of nuclear factor-κB and Janus kinase 2 (JAK2)/Signal Transducer and Activator of Transcription 3 (STAT3) signalling and production of cytokines in vascular endothelial cell-derived EA.hy926 cells. Taken together, DF has pro-angiogenic, anti-apoptotic and anti-inflammatory effects on endothelial cells. DF is a potentially useful agent to prevent the development of, and treat individuals with, endothelial cell injury-related complications after haematopoietic stem cell transplantation. Schattauer GmbH Stuttgart.

  15. Signal Transducer and Activator of Transcription 1 (STAT1) is Essential for Chromium Silencing of Gene Induction in Human Airway Epithelial Cells

    PubMed Central

    Nemec, Antonia A.; Barchowsky, Aaron

    2009-01-01

    Hexavalent chromium (Cr(VI)) promotes lung injury and pulmonary diseases through poorly defined mechanisms that may involve the silencing of inducible protective genes. The current study investigated the hypothesis that Cr(VI) actively signals through a signal transducer and activator of transcription 1 (STAT1)–dependent pathway to silence nickel (Ni)–induced expression of vascular endothelial cell growth factor A (VEGFA), an important mediator of lung injury and repair. In human bronchial airway epithelial (BEAS-2B) cells, Ni-induced VEGFA transcription by stimulating an extracellular regulated kinase (ERK) signaling cascade that involved Src kinase–activated Sp1 transactivation, as well as increased hypoxia-inducible factor-1α (HIF-1α) stabilization and DNA binding. Ni-stimulated ERK, Src, and HIF-1α activities, as well as Ni-induced VEGFA transcript levels were inhibited in Cr(VI)-exposed cells. We previously demonstrated that Cr(VI) stimulates STAT1 to suppress VEGFA expression. In BEAS-2B cells stably expressing STAT1 short hairpin RNA, Cr(VI) increased VEGFA transcript levels and Sp1 transactivation. Moreover, in the absence of STAT1, Cr(VI), and Ni coexposures positively interacted to further increase VEGFA transcripts. This study demonstrates that metal-stimulated signaling cascades interact to regulate transcription and induction of adaptive or repair responses in airway cells. In addition, the data implicate STAT1 as a rate limiting mediator of Cr(VI)-stimulated gene regulation and suggest that cells lacking STAT1, such as many tumor cell lines, have opposite responses to Cr(VI) relative to normal cells. PMID:19403854

  16. Different designs of kinase-phosphatase interactions and phosphatase sequestration shapes the robustness and signal flow in the MAPK cascade

    PubMed Central

    2012-01-01

    Background The three layer mitogen activated protein kinase (MAPK) signaling cascade exhibits different designs of interactions between its kinases and phosphatases. While the sequential interactions between the three kinases of the cascade are tightly preserved, the phosphatases of the cascade, such as MKP3 and PP2A, exhibit relatively diverse interactions with their substrate kinases. Additionally, the kinases of the MAPK cascade can also sequester their phosphatases. Thus, each topologically distinct interaction design of kinases and phosphatases could exhibit unique signal processing characteristics, and the presence of phosphatase sequestration may lead to further fine tuning of the propagated signal. Results We have built four architecturally distinct types of models of the MAPK cascade, each model with identical kinase-kinase interactions but unique kinases-phosphatases interactions. Our simulations unravelled that MAPK cascade’s robustness to external perturbations is a function of nature of interaction between its kinases and phosphatases. The cascade’s output robustness was enhanced when phosphatases were sequestrated by their target kinases. We uncovered a novel implicit/hidden negative feedback loop from the phosphatase MKP3 to its upstream kinase Raf-1, in a cascade resembling the B cell MAPK cascade. Notably, strength of the feedback loop was reciprocal to the strength of phosphatases’ sequestration and stronger sequestration abolished the feedback loop completely. An experimental method to verify the presence of the feedback loop is also proposed. We further showed, when the models were activated by transient signal, memory (total time taken by the cascade output to reach its unstimulated level after removal of signal) of a cascade was determined by the specific designs of interaction among its kinases and phosphatases. Conclusions Differences in interaction designs among the kinases and phosphatases can differentially shape the robustness and

  17. Crosstalk between mitochondrial stress signals regulates yeast chronological lifespan.

    PubMed

    Schroeder, Elizabeth A; Shadel, Gerald S

    2014-01-01

    Mitochondrial DNA (mtDNA) exists in multiple copies per cell and is essential for oxidative phosphorylation. Depleted or mutated mtDNA promotes numerous human diseases and may contribute to aging. Reduced TORC1 signaling in the budding yeast, Saccharomyces cerevisiae, extends chronological lifespan (CLS) in part by generating a mitochondrial ROS (mtROS) signal that epigenetically alters nuclear gene expression. To address the potential requirement for mtDNA maintenance in this response, we analyzed strains lacking the mitochondrial base-excision repair enzyme Ntg1p. Extension of CLS by mtROS signaling and reduced TORC1 activity, but not caloric restriction, was abrogated in ntg1Δ strains that exhibited mtDNA depletion without defects in respiration. The DNA damage response (DDR) kinase Rad53p, which transduces pro-longevity mtROS signals, is also activated in ntg1Δ strains. Restoring mtDNA copy number alleviated Rad53p activation and re-established CLS extension following mtROS signaling, indicating that Rad53p senses mtDNA depletion directly. Finally, DDR kinases regulate nucleus-mitochondria localization dynamics of Ntg1p. From these results, we conclude that the DDR pathway senses and may regulate Ntg1p-dependent mtDNA stability. Furthermore, Rad53p senses multiple mitochondrial stresses in a hierarchical manner to elicit specific physiological outcomes, exemplified by mtDNA depletion overriding the ability of Rad53p to transduce an adaptive mtROS longevity signal. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  18. Conformational Changes of an Interdomain Linker Mediate Mechanical Signal Transmission in Sensor Kinase BvgS

    PubMed Central

    Lesne, Elodie; Dupré, Elian; Locht, Camille

    2017-01-01

    ABSTRACT The whooping cough agent, Bordetella pertussis, controls the expression of its large virulence regulon in a coordinated manner through the two-component system BvgAS. BvgS is a dimeric, multidomain sensor kinase. Each monomer comprises, in succession, tandem periplasmic Venus flytrap (VFT) domains, a transmembrane segment, a cytoplasmic Per-Arnt-Sim (PAS) domain, a kinase module, and additional phosphorelay domains. BvgS shifts between kinase and phosphatase modes of activity in response to chemical modulators that modify the clamshell motions of the VFT domains. We have shown previously that this regulation involves a shift between distinct states of conformation and dynamics of the two-helix coiled-coil linker preceding the enzymatic module. In this work, we determined the mechanism of signal transduction across the membrane via a first linker, which connects the VFT and PAS domains of BvgS, using extensive cysteine cross-linking analyses and other approaches. Modulator perception by the periplasmic domains appears to trigger a small, symmetrical motion of the transmembrane segments toward the periplasm, causing rearrangements of the noncanonical cytoplasmic coiled coil that follows. As a consequence, the interface of the PAS domains is modified, which affects the second linker and eventually causes the shift of enzymatic activity. The major features of this first linker are well conserved among BvgS homologs, indicating that the mechanism of signal transduction unveiled here is likely to be generally relevant for this family of sensor kinases. IMPORTANCE Bordetella pertussis produces virulence factors coordinately regulated by the two-component system BvgAS. BvgS is a sensor kinase, and BvgA is a response regulator that activates gene transcription when phosphorylated by BvgS. Sensor kinases homologous to BvgS are also found in other pathogens. Our goal is to decipher the mechanisms of BvgS signaling, since these sensor kinases may represent new targets

  19. Trichinella spiralis infection enhances protein kinase C phosphorylation in guinea pig alveolar macrophages.

    PubMed

    Dzik, J M; Zieliński, Z; Cieśla, J; Wałajtys-Rode, E

    2010-03-01

    To learn more about the signalling pathways involved in superoxide anion production in guinea pig alveolar macrophages, triggered by Trichinella spiralis infection, protein level and phosphorylation of mitogen activated protein (MAP) kinases and protein kinase C (PKC) were investigated. Infection with T. spiralis, the nematode having 'lung phase' during colonization of the host, enhances PKC phosphorylation in guinea pig alveolar macrophages. Isoenzymes beta and delta of PKC have been found significantly phosphorylated, although their location was not changed as a consequence of T. spiralis infection. Neither in macrophages from T. spiralis-infected guinea pig nor in platelet-activating factor (PAF)-stimulated macrophages from uninfected animals, participation of MAP kinases in respiratory burst activation was statistically significant. The parasite antigens seem to act through macrophage PAF receptors, transducing a signal for enhanced NADPH oxidase activity, as stimulating effect of newborn larvae homogenate on respiratory burst was abolished by specific PAF receptor antagonist CV 6209. A suppressive action of T. spiralis larvae on host alveolar macrophage innate immunological response was reflected by diminished protein level of ERK2 kinase and suppressed superoxide anion production, in spite of high level of PKC phosphorylation.

  20. Cytokine receptor signaling is required for the survival of ALK− anaplastic large cell lymphoma, even in the presence of JAK1/STAT3 mutations

    PubMed Central

    Chen, Jing; Zhang, Yong; Petrus, Michael N.; Xiao, Wenming; Nicolae, Alina; Raffeld, Mark; Pittaluga, Stefania; Bamford, Richard N.; Nakagawa, Masao; Ouyang, Sunny Tianyi; Epstein, Alan L.; Kadin, Marshall E.; Del Mistro, Annarose; Woessner, Richard; Jaffe, Elaine S.; Waldmann, Thomas A.

    2017-01-01

    Activating Janus kinase (JAK) and signal transducer and activator of transcription (STAT) mutations have been discovered in many T-cell malignancies, including anaplastic lymphoma kinase (ALK)− anaplastic large cell lymphomas (ALCLs). However, such mutations occur in a minority of patients. To investigate the clinical application of targeting JAK for ALK− ALCL, we treated ALK− cell lines of various histological origins with JAK inhibitors. Interestingly, most exogenous cytokine-independent cell lines responded to JAK inhibition regardless of JAK mutation status. JAK inhibitor sensitivity correlated with the STAT3 phosphorylation status of tumor cells. Using retroviral shRNA knockdown, we have demonstrated that these JAK inhibitor-sensitive cells are dependent on both JAK1 and STAT3 for survival. JAK1 and STAT3 gain-of-function mutations were found in some, but not all, JAK inhibitor-sensitive cells. Moreover, the mutations alone cannot explain the JAK1/STAT3 dependency, given that wild-type JAK1 or STAT3 was sufficient to promote cell survival in the cells that had either JAK1or STAT3 mutations. To investigate whether other mechanisms were involved, we knocked down upstream receptors GP130 or IL-2Rγ. Knockdown of GP130 or IL-2Rγ induced cell death in selected JAK inhibitor-sensitive cells. High expression levels of cytokines, including IL-6, were demonstrated in cell lines as well as in primary ALK− ALCL tumors. Finally, ruxolitinib, a JAK1/2 inhibitor, was effective in vivo in a xenograft ALK− ALCL model. Our data suggest that cytokine receptor signaling is required for tumor cell survival in diverse forms of ALK− ALCL, even in the presence of JAK1/STAT3 mutations. Therefore, JAK inhibitor therapy might benefit patients with ALK− ALCL who are phosphorylated STAT3+. PMID:28356514

  1. JAK and MPL mutations in myeloid malignancies.

    PubMed

    Tefferi, Ayalew

    2008-03-01

    The Janus family of non-receptor tyrosine kinases (JAK1, JAK2, JAK3 and tyrosine kinase 2) transduces signals downstream of type I and II cytokine receptors via signal transducers and activators of transcription (STATs). JAK3 is important in lymphoid and JAK2 in myeloid cell proliferation and differentiation. The thrombopoietin receptor MPL is one of several JAK2 cognate receptors and is essential for myelopoiesis in general and megakaryopoiesis in particular. Germline loss-of-function (LOF) JAK3 and MPL mutations cause severe combined immunodeficiency and congenital amegakaryocytic thrombocytopenia, respectively. Germline gain-of-function (GOF) MPL mutation (MPLS505N) causes familial thrombocytosis. Somatic JAK3 (e.g. JAK3A572V, JAK3V722I, JAK3P132T) and fusion JAK2 (e.g. ETV6-JAK2, PCM1-JAK2, BCR-JAK2) mutations have respectively been described in acute megakaryocytic leukemia and acute leukemia/chronic myeloid malignancies. However, current attention is focused on JAK2 (e.g. JAK2V617F, JAK2 exon 12 mutations) and MPL (e.g. MPLW515L/K/S, MPLS505N) mutations associated with myeloproliferative neoplasms (MPNs). A JAK2 mutation, primarily JAK2V617F, is invariably associated with polycythemia vera (PV). The latter mutation also occurs in the majority of patients with essential thrombocythemia (ET) or primary myelofibrosis (PMF). MPL mutational frequency in MPNs is substantially less (<10%). In general, despite a certain degree of genotype - phenotype correlations, the prognostic relevance of harbouring one of these mutations, or their allele burden when present, remains dubious. Regardless, based on the logical assumption that amplified JAK-STAT signalling is central to the pathogenesis of PV, ET and PMF, several anti-JAK2 tyrosine kinase inhibitors have been developed and are currently being tested in humans with these disorders.

  2. Protein Kinase D1 Signaling in Angiogenic Gene Expression and VEGF-Mediated Angiogenesis.

    PubMed

    Ren, Bin

    2016-01-01

    Protein kinase D 1 (PKD-1) is a signaling kinase important in fundamental cell functions including migration, proliferation, and differentiation. PKD-1 is also a key regulator of gene expression and angiogenesis that is essential for cardiovascular development and tumor progression. Further understanding molecular aspects of PKD-1 signaling in the regulation of angiogenesis may have translational implications in obesity, cardiovascular disease, and cancer. The author will summarize and provide the insights into molecular mechanisms by which PKD-1 regulates transcriptional expression of angiogenic genes, focusing on the transcriptional regulation of CD36 by PKD-1-FoxO1 signaling axis along with the potential implications of this axis in arterial differentiation and morphogenesis. He will also discuss a new concept of dynamic balance between proangiogenic and antiangiogenic signaling in determining angiogenic switch, and stress how PKD-1 signaling regulates VEGF signaling-mediated angiogenesis.

  3. Protein Kinase D1 Signaling in Angiogenic Gene Expression and VEGF-Mediated Angiogenesis

    PubMed Central

    Ren, Bin

    2016-01-01

    Protein kinase D 1 (PKD-1) is a signaling kinase important in fundamental cell functions including migration, proliferation, and differentiation. PKD-1 is also a key regulator of gene expression and angiogenesis that is essential for cardiovascular development and tumor progression. Further understanding molecular aspects of PKD-1 signaling in the regulation of angiogenesis may have translational implications in obesity, cardiovascular disease, and cancer. The author will summarize and provide the insights into molecular mechanisms by which PKD-1 regulates transcriptional expression of angiogenic genes, focusing on the transcriptional regulation of CD36 by PKD-1-FoxO1 signaling axis along with the potential implications of this axis in arterial differentiation and morphogenesis. He will also discuss a new concept of dynamic balance between proangiogenic and antiangiogenic signaling in determining angiogenic switch, and stress how PKD-1 signaling regulates VEGF signaling-mediated angiogenesis. PMID:27200349

  4. Loss of Mitogen-Activated Protein Kinase Kinase Kinase 4 (MAP3K4) Reveals a Requirement for MAPK Signalling in Mouse Sex Determination

    PubMed Central

    Bogani, Debora; Siggers, Pam; Brixey, Rachel; Warr, Nick; Beddow, Sarah; Edwards, Jessica; Williams, Debbie; Wilhelm, Dagmar; Koopman, Peter; Flavell, Richard A.; Chi, Hongbo; Ostrer, Harry; Wells, Sara; Cheeseman, Michael; Greenfield, Andy

    2009-01-01

    Sex determination in mammals is controlled by the presence or absence of the Y-linked gene SRY. In the developing male (XY) gonad, sex-determining region of the Y (SRY) protein acts to up-regulate expression of the related gene, SOX9, a transcriptional regulator that in turn initiates a downstream pathway of testis development, whilst also suppressing ovary development. Despite the requirement for a number of transcription factors and secreted signalling molecules in sex determination, intracellular signalling components functioning in this process have not been defined. Here we report a role for the phylogenetically ancient mitogen-activated protein kinase (MAPK) signalling pathway in mouse sex determination. Using a forward genetic screen, we identified the recessive boygirl (byg) mutation. On the C57BL/6J background, embryos homozygous for byg exhibit consistent XY gonadal sex reversal. The byg mutation is an A to T transversion causing a premature stop codon in the gene encoding MAP3K4 (also known as MEKK4), a mitogen-activated protein kinase kinase kinase. Analysis of XY byg/byg gonads at 11.5 d post coitum reveals a growth deficit and a failure to support mesonephric cell migration, both early cellular processes normally associated with testis development. Expression analysis of mutant XY gonads at the same stage also reveals a dramatic reduction in Sox9 and, crucially, Sry at the transcript and protein levels. Moreover, we describe experiments showing the presence of activated MKK4, a direct target of MAP3K4, and activated p38 in the coelomic region of the XY gonad at 11.5 d post coitum, establishing a link between MAPK signalling in proliferating gonadal somatic cells and regulation of Sry expression. Finally, we provide evidence that haploinsufficiency for Map3k4 accounts for T-associated sex reversal (Tas). These data demonstrate that MAP3K4-dependent signalling events are required for normal expression of Sry during testis development, and create a novel

  5. Janus droplets: liquid marbles coated with dielectric/semiconductor particles.

    PubMed

    Bormashenko, Edward; Bormashenko, Yelena; Pogreb, Roman; Gendelman, Oleg

    2011-01-04

    The manufacturing of water droplets wrapped with two different powders, carbon black (semiconductor) and polytetrafluoroethylene (dielectric), is presented. Droplets composed of two hemispheres (Janus droplets) characterized by various physical and chemical properties are reported first. Watermelon-like striped liquid marbles are reported. Janus droplets remained stable on solid and liquid supports and could be activated with an electric field.

  6. Transcriptional activation by MEIS1A in response to protein kinase A signaling requires the transducers of regulated CREB family of CREB co-activators.

    PubMed

    Goh, Siew-Lee; Looi, Yvonne; Shen, Hui; Fang, Jun; Bodner, Caroline; Houle, Martin; Ng, Andy Cheuk-Him; Screaton, Robert A; Featherstone, Mark

    2009-07-10

    The transcription factor encoded by the murine ecotropic integration site 1 gene (MEIS1) is a partner of HOX and PBX proteins. It has been implicated in embryonic patterning and leukemia, and causally linked to restless legs syndrome. The MEIS1A C terminus harbors a transcriptional activation domain that is stimulated by protein kinase A (PKA) in a manner dependent on the co-activator of cAMP response element-binding protein (CREB), CREB-binding protein (CBP). We explored the involvement of another mediator of PKA-inducible transcription, namely the CREB co-activators transducers of regulated CREB activity (TORCs). Overexpression of TORC1 or TORC2 bypassed PKA for activation by MEIS1A. Co-immunoprecipitation experiments demonstrated a physical interaction between MEIS1 and TORC2 that is dependent on the MEIS1A C terminus, whereas chromatin immunoprecipitation revealed PKA-inducible recruitment of MEIS1, PBX1, and TORC2 on the MEIS1 target genes Hoxb2 and Meis1. The MEIS1 interaction domain on TORC1 was mapped to the N-terminal coiled-coil region, and TORC1 mutants lacking this domain attenuated the response to PKA on a natural MEIS1A target enhancer. Thus, TORCs physically cooperate with MEIS1 to achieve PKA-inducible transactivation through the MEIS1A C terminus, suggesting a concerted action in developmental and oncogenic processes.

  7. Transcriptional Activation by MEIS1A in Response to Protein Kinase A Signaling Requires the Transducers of Regulated CREB Family of CREB Co-activators*

    PubMed Central

    Goh, Siew-Lee; Looi, Yvonne; Shen, Hui; Fang, Jun; Bodner, Caroline; Houle, Martin; Ng, Andy Cheuk-Him; Screaton, Robert A.; Featherstone, Mark

    2009-01-01

    The transcription factor encoded by the murine ecotropic integration site 1 gene (MEIS1) is a partner of HOX and PBX proteins. It has been implicated in embryonic patterning and leukemia, and causally linked to restless legs syndrome. The MEIS1A C terminus harbors a transcriptional activation domain that is stimulated by protein kinase A (PKA) in a manner dependent on the co-activator of cAMP response element-binding protein (CREB), CREB-binding protein (CBP). We explored the involvement of another mediator of PKA-inducible transcription, namely the CREB co-activators transducers of regulated CREB activity (TORCs). Overexpression of TORC1 or TORC2 bypassed PKA for activation by MEIS1A. Co-immunoprecipitation experiments demonstrated a physical interaction between MEIS1 and TORC2 that is dependent on the MEIS1A C terminus, whereas chromatin immunoprecipitation revealed PKA-inducible recruitment of MEIS1, PBX1, and TORC2 on the MEIS1 target genes Hoxb2 and Meis1. The MEIS1 interaction domain on TORC1 was mapped to the N-terminal coiled-coil region, and TORC1 mutants lacking this domain attenuated the response to PKA on a natural MEIS1A target enhancer. Thus, TORCs physically cooperate with MEIS1 to achieve PKA-inducible transactivation through the MEIS1A C terminus, suggesting a concerted action in developmental and oncogenic processes. PMID:19473990

  8. STATs: An Old Story, Yet Mesmerizing

    PubMed Central

    Abroun, Saeid; Saki, Najmaldin; Ahmadvand, Mohammad; Asghari, Farahnaz; Salari, Fatemeh; Rahim, Fakher

    2015-01-01

    Signal transducers and activators of transcription (STATs) are cytoplasmic transcription factors that have a key role in cell fate. STATs, a protein family comprised of seven members, are proteins which are latent cytoplasmic transcription factors that convey signals from the cell surface to the nucleus through activation by cytokines and growth factors. The signaling pathways have diverse biological functions that include roles in cell differentiation, proliferation, development, apoptosis, and inflammation which place them at the center of a very active area of research. In this review we explain Janus kinase (JAK)/STAT signaling and focus on STAT3, which is transient from cytoplasm to nucleus after phosphorylation. This procedure controls fundamental biological processes by regulating nuclear genes controlling cell proliferation, survival, and development. In some hematopoietic disorders and cancers, overexpression and activation of STAT3 result in high proliferation, suppression of cell differentiation and inhibition of cell maturation. This article focuses on STAT3 and its role in malignancy, in addition to the role of microRNAs (miRNAs) on STAT3 activation in certain cancers. PMID:26464811

  9. STATs: An Old Story, Yet Mesmerizing.

    PubMed

    Abroun, Saeid; Saki, Najmaldin; Ahmadvand, Mohammad; Asghari, Farahnaz; Salari, Fatemeh; Rahim, Fakher

    2015-01-01

    Signal transducers and activators of transcription (STATs) are cytoplasmic transcription factors that have a key role in cell fate. STATs, a protein family comprised of seven members, are proteins which are latent cytoplasmic transcription factors that convey signals from the cell surface to the nucleus through activation by cytokines and growth factors. The signaling pathways have diverse biological functions that include roles in cell differentiation, proliferation, development, apoptosis, and inflammation which place them at the center of a very active area of research. In this review we explain Janus kinase (JAK)/STAT signaling and focus on STAT3, which is transient from cytoplasm to nucleus after phosphorylation. This procedure controls fundamental biological processes by regulating nuclear genes controlling cell proliferation, survival, and development. In some hematopoietic disorders and cancers, overexpression and activation of STAT3 result in high proliferation, suppression of cell differentiation and inhibition of cell maturation. This article focuses on STAT3 and its role in malignancy, in addition to the role of microRNAs (miRNAs) on STAT3 activation in certain cancers.

  10. Preparation of polymeric Janus particles by directional UV-induced reactions.

    PubMed

    Liu, Lianying; Ren, Mingwei; Yang, Wantai

    2009-09-15

    Polymeric Janus particles are obtained by UV-induced selective surface grafting polymerizations and coupling reactions, in virtue of the light-absorption of photoreactive materials such as the immobilized photoinitiator and spread photoinitiator solution on the surfaces exposed to UV light and the sheltering of densely arrayed immovable particles from light. Varying the monomers or macromolecules applied in photografting polymerization or coupling reaction, and choosing diverse polymeric particles of various size, bicolor and amphiphilic Janus particles could be successfully achieved. Observations by fluorescence microscope, scanning electron microscope ,and transmission electron microscope confirmed the asymmetrical morphology of the resultant Janus particles.

  11. The IRAK homolog Pelle is the functional counterpart of IκB kinase in the Drosophila Toll pathway.

    PubMed

    Daigneault, Jessica; Klemetsaune, Liv; Wasserman, Steven A

    2013-01-01

    Toll receptors transduce signals that activate Rel-family transcription factors, such as NF-κB, by directing proteolytic degradation of inhibitor proteins. In mammals, the IκB Kinase (IKK) phosphorylates the inhibitor IκBα. A βTrCP protein binds to phosphorylated IκBα, triggering ubiquitination and proteasome mediated degradation. In Drosophila, Toll signaling directs Cactus degradation via a sequence motif that is highly similar to that in IκBα, but without involvement of IKK. Here we show that Pelle, the homolog of a mammalian regulator of IKK, acts as a Cactus kinase. We further find that the fly βTrCP protein Slimb is required in cultured cells to mediate Cactus degradation. These findings enable us for the first time to trace an uninterrupted pathway from the cell surface to the nucleus for Drosophila Toll signaling.

  12. The IRAK Homolog Pelle Is the Functional Counterpart of IκB Kinase in the Drosophila Toll Pathway

    PubMed Central

    Daigneault, Jessica; Klemetsaune, Liv; Wasserman, Steven A.

    2013-01-01

    Toll receptors transduce signals that activate Rel-family transcription factors, such as NF-κB, by directing proteolytic degradation of inhibitor proteins. In mammals, the IκB Kinase (IKK) phosphorylates the inhibitor IκBα. A βTrCP protein binds to phosphorylated IκBα, triggering ubiquitination and proteasome mediated degradation. In Drosophila, Toll signaling directs Cactus degradation via a sequence motif that is highly similar to that in IκBα, but without involvement of IKK. Here we show that Pelle, the homolog of a mammalian regulator of IKK, acts as a Cactus kinase. We further find that the fly βTrCP protein Slimb is required in cultured cells to mediate Cactus degradation. These findings enable us for the first time to trace an uninterrupted pathway from the cell surface to the nucleus for Drosophila Toll signaling. PMID:24086459

  13. The protist, Monosiga brevicollis, has a tyrosine kinase signaling network more elaborate and diverse than found in any known metazoan.

    PubMed

    Manning, Gerard; Young, Susan L; Miller, W Todd; Zhai, Yufeng

    2008-07-15

    Tyrosine kinase signaling has long been considered a hallmark of intercellular communication, unique to multicellular animals. Our genomic analysis of the unicellular choanoflagellate Monosiga brevicollis discovers a remarkable count of 128 tyrosine kinases, 38 tyrosine phosphatases, and 123 phosphotyrosine (pTyr)-binding SH2 proteins, all higher counts than seen in any metazoan. This elaborate signaling network shows little orthology to metazoan counterparts yet displays many innovations reminiscent of metazoans. These include extracellular domains structurally related to those of metazoan receptor kinases, alternative methods for membrane anchoring and phosphotyrosine interaction in cytoplasmic kinases, and domain combinations that link kinases to small GTPase signaling and transcription. These proteins also display a wealth of combinations of known signaling domains. This uniquely divergent and elaborate signaling network illuminates the early evolution of pTyr signaling, explores innovative ways to traverse the cellular signaling circuitry, and shows extensive convergent evolution, highlighting pervasive constraints on pTyr signaling.

  14. Calpain-mediated proteolysis of polycystin-1 C-terminus induces JAK2 and ERK signal alterations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kim, Hyunho; Department of Medicine, University of Maryland, Baltimore, MD; Kang, Ah-Young

    2014-01-01

    Autosomal dominant polycystic kidney disease (ADPKD), a hereditary renal disease caused by mutations in PKD1 (85%) or PKD2 (15%), is characterized by the development of gradually enlarging multiple renal cysts and progressive renal failure. Polycystin-1 (PC1), PKD1 gene product, is an integral membrane glycoprotein which regulates a number of different biological processes including cell proliferation, apoptosis, cell polarity, and tubulogenesis. PC1 is a target of various proteolytic cleavages and proteosomal degradations, but its role in intracellular signaling pathways remains poorly understood. Herein, we demonstrated that PC1 is a novel substrate for μ- and m-calpains, which are calcium-dependent cysteine proteases. Overexpressionmore » of PC1 altered both Janus-activated kinase 2 (JAK2) and extracellular signal-regulated kinase (ERK) signals, which were independently regulated by calpain-mediated PC1 degradation. They suggest that the PC1 function on JAK2 and ERK signaling pathways might be regulated by calpains in response to the changes in intracellular calcium concentration. - Highlights: • Polycystin-1 is a target of ubiquitin-independent degradation by calpains. • The PEST domain is required for calpain-mediated degradation of polycystin-1. • Polycystin-1 may independently regulate JAK2 and ERK signaling pathways.« less

  15. Ultrasound transducer modeling-received voltage signals and the use of half-wavelength window layers with acoustic coupling layers.

    PubMed

    Willatzen, M

    1999-01-01

    A general set of modeling equations for lossless one-dimensional multilayer ultrasound transducers is presented based on first principles. In particular, a direct relationship between ultrasound transducer results and the underlying physical principles of electroacoustics is given. As such, the model may provide better physical understanding for designers not fully versed in electrical circuits theory or in linear system analyses. The model is suitable for time-domain analysis and monofrequency design. Special attention is given to the determination of the time-dependent voltage across the receiver electrodes subject to a general voltage input, but information on any (dynamic) variable of interest is provided. The basic equations governing the dynamics of the multilayer structure acting as transmitter as well as receiver are solved by Fourier analysis and by imposing continuity of velocity and pressure between layers. Sound transmission between the two piezoelectric circuits is assumed to take place in a water bath such that the Rayleigh equation can be used to obtain the incoming pressure at the receiver aperture from the acceleration of the opposing transmitter aperture. Comparison with experimental results is possible by allowing coupling to external electric impedances. A numerical test case using a multilayered 1-MHz transducer for flow meter applications was considered and good agreement with experiments was obtained in terms of voltage signals. The transducer contains a half-wavelength stainless steel layer needed to resist corrosion, the ability to operate at temperatures in a wide range from 20 to 150 degrees Celsius, resistance to impact from flowing particles in the medium, high pressure or vacuum, and pH values up to 10 in some locations. The influence of epoxy glue and grease acoustic coupling layers-between the piezoceramics and the stainless steel layer-in the range from 1 to 70 mum was examined. It was shown that, for the same layer thickness, epoxy

  16. Epstein-Barr Virus Hijacks DNA Damage Response Transducers to Orchestrate Its Life Cycle.

    PubMed

    Hau, Pok Man; Tsao, Sai Wah

    2017-11-16

    The Epstein-Barr virus (EBV) is a ubiquitous virus that infects most of the human population. EBV infection is associated with multiple human cancers, including Burkitt's lymphoma, Hodgkin's lymphoma, a subset of gastric carcinomas, and almost all undifferentiated non-keratinizing nasopharyngeal carcinoma. Intensive research has shown that EBV triggers a DNA damage response (DDR) during primary infection and lytic reactivation. The EBV-encoded viral proteins have been implicated in deregulating the DDR signaling pathways. The consequences of DDR inactivation lead to genomic instability and promote cellular transformation. This review summarizes the current understanding of the relationship between EBV infection and the DDR transducers, including ATM (ataxia telangiectasia mutated), ATR (ATM and Rad3-related), and DNA-PK (DNA-dependent protein kinase), and discusses how EBV manipulates the DDR signaling pathways to complete the replication process of viral DNA during lytic reactivation.

  17. Somatostatin/somatostatin receptor signalling: phosphotyrosine phosphatases.

    PubMed

    Florio, Tullio

    2008-05-14

    Activation of phosphotyrosine phosphatases (PTPs) by somatostatin receptor (SSTR) represents one of the main intracellular mechanisms involved in the antiproliferative effect of somatostatin (SST) and analogues. Since their molecular cloning, the role of PTPs is emerging as a major regulator of different cell functions including cell proliferation, differentiation, cell to cell interactions, cell matrix adhesion and cell migration. It was demonstrated that PTPs possess high substrate specificity and their activity is tightly regulated. Importantly, different G protein-coupled receptors transduce their biological activities through PTPs. PTPs were identified as down-stream effectors of SSTRs to transduce antiproliferative signals, and so far, three family members (SHP-1, SHP-2 and DEP-1/PTPeta) have been identified as selective SSTR intracellular effectors. Here, the molecular mechanisms leading SSTRs to regulate PTP activity are discussed, focusing on recent data showing a close interplay between PTPs and tyrosine kinases to transduce tumoral cell growth arrest following SST analogs administration.

  18. Polymeric Janus Nanoparticles: Recent Advances in Synthetic Strategies, Materials Properties, and Applications.

    PubMed

    Fan, Xiaoshan; Yang, Jing; Loh, Xian Jun; Li, Zibiao

    2018-06-13

    Polymeric Janus nanoparticles with two sides of incompatible chemistry have received increasing attention due to their tunable asymmetric structure and unique material characteristics. Recently, with the rapid progress in controlled polymerization combined with novel fabrication techniques, a large array of functional polymeric Janus particles are diversified with sophisticated architecture and applications. In this review, the most recently developed strategies for controlled synthesis of polymeric Janus nanoparticles with well-defined size and complex superstructures are summarized. In addition, the pros and cons of each approach in mediating the anisotropic shapes of polymeric Janus particles as well as their asymmetric spatial distribution of chemical compositions and functionalities are discussed and compared. Finally, these newly developed structural nanoparticles with specific shapes and surface functions orientated applications in different domains are also discussed, followed by the perspectives and challenges faced in the further advancement of polymeric Janus nanoparticles as high performance materials. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Mycosporine-Like Amino Acids Promote Wound Healing through Focal Adhesion Kinase (FAK) and Mitogen-Activated Protein Kinases (MAP Kinases) Signaling Pathway in Keratinocytes

    PubMed Central

    Choi, Yun-Hee; Yang, Dong Joo; Kulkarni, Atul; Moh, Sang Hyun; Kim, Ki Woo

    2015-01-01

    Mycosporine-like amino acids (MAAs) are secondary metabolites found in diverse marine, freshwater, and terrestrial organisms. Evidence suggests that MAAs have several beneficial effects on skin homeostasis such as protection against UV radiation and reactive oxygen species (ROS). In addition, MAAs are also involved in the modulation of skin fibroblasts proliferation. However, the regulatory function of MAAs on wound repair in human skin is not yet clearly elucidated. To investigate the roles of MAAs on the wound healing process in human keratinocytes, three MAAs, Shinorine (SH), Mycosporine-glycine (M-Gly), and Porphyra (P334) were purified from Chlamydomonas hedlyei and Porphyra yezoensis. We found that SH, M-Gly, and P334 have significant effects on the wound healing process in human keratinocytes and these effects were mediated by activation of focal adhesion kinases (FAK), extracellular signal-regulated kinases (ERK), and c-Jun N-terminal kinases (JNK). These results suggest that MAAs accelerate wound repair by activating the FAK-MAPK signaling pathways. This study also indicates that MAAs can act as a new wound healing agent and further suggests that MAAs might be a novel biomaterial for wound healing therapies. PMID:26703626

  20. Differential activation of the Ras/extracellular-signal-regulated protein kinase pathway is responsible for the biological consequences induced by the Axl receptor tyrosine kinase.

    PubMed

    Fridell, Y W; Jin, Y; Quilliam, L A; Burchert, A; McCloskey, P; Spizz, G; Varnum, B; Der, C; Liu, E T

    1996-01-01

    To understand the mechanism of Axl signaling, we have initiated studies to delineate downstream components in interleukin-3-dependent 32D cells by using a chimeric receptor containing the recombinant epidermal growth factor (EGF) receptor extracellular and transmembrane domains and the Axl kinase domain (EAK [for EGF receptor-Axl kinase]). We have previously shown that upon exogenous EGF stimulation, 32D-EAK cells are capable of proliferation in the absence of interleukin-3. With this system, we determined that EAK-induced cell survival and mitogenesis are dependent upon the Ras/extracellular-signal-regulated protein kinase (ERK) cascade. Although the phosphatidylinositol-3 kinase pathway is activated upon EAK signaling, it appears to be dispensable for the biological actions of the Axl kinase. Furthermore, we demonstrated that different threshold levels of Ras/ERK activation are needed to induce a block to apoptosis or proliferation in 32D cells. Recently, we have identified an Axl ligand, GAS6. Surprisingly, GAS6-stimulated 32D-Axl cells exhibited no blockage to apoptosis or mitogenic response which is correlated with the absence of Ras/ERK activation. Taken together, these data suggest that different extracellular domains dramatically alter the intracellular response of the Axl kinase. Furthermore, our data suggest that the GAS6-Axl interaction does not induce mitogenesis and that its exact role remains to be determined.

  1. Heparin-Poloxamer Thermosensitive Hydrogel Loaded with bFGF and NGF Enhances Peripheral Nerve Regeneration in Diabetic Rats.

    PubMed

    Li, Rui; Li, Yiyang; Wu, Yanqing; Zhao, Yingzheng; Chen, Huanwen; Yuan, Yuan; Xu, Ke; Zhang, Hongyu; Lu, Yingfeng; Wang, Jian; Li, Xiaokun; Jia, Xiaofeng; Xiao, Jian

    2018-06-01

    Peripheral nerve injury (PNI) is a major burden to society with limited therapeutic options, and novel biomaterials have great potential for shifting the current paradigm of treatment. With a rising prevalence of chronic illnesses such as diabetes mellitus (DM), treatment of PNI is further complicated, and only few studies have proposed therapies suitable for peripheral nerve regeneration in DM. To provide a supportive environment to restore structure and/or function of nerves in DM, we developed a novel thermo-sensitive heparin-poloxamer (HP) hydrogel co-delivered with basic fibroblast growth factor (bFGF) and nerve growth factor (NGF) in diabetic rats with sciatic nerve crush injury. The delivery vehicle not only had a good affinity for large amounts of growth factors (GFs), but also controlled their release in a steady fashion, preventing degradation in vitro. In vivo, compared with HP hydrogel alone or direct GFs administration, GFs-HP hydrogel treatment is more effective at facilitating Schwann cell (SC) proliferation, leading to an increased expression of nerve associated structural proteins, enhanced axonal regeneration and remyelination, and improved recovery of motor function (all p < 0.05). Our mechanistic investigation also revealed that these neuroprotective and neuroregenerative effects of the GFs-HP hydrogel may be associated with activations of phosphatidylinositol 3 kinase and protein kinase B (PI3K/Akt), janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3), and mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathways. Our work provides a promising therapy option for peripheral nerve regeneration in patients with DM. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Recent Progress on Liver Kinase B1 (LKB1): Expression, Regulation, Downstream Signaling and Cancer Suppressive Function

    PubMed Central

    Gan, Ren-You; Li, Hua-Bin

    2014-01-01

    Liver kinase B1 (LKB1), known as a serine/threonine kinase, has been identified as a critical cancer suppressor in many cancer cells. It is a master upstream kinase of 13 AMP-activated protein kinase (AMPK)-related protein kinases, and possesses versatile biological functions. LKB1 gene is mutated in many cancers, and its protein can form different protein complexes with different cellular localizations in various cell types. The expression of LKB1 can be regulated through epigenetic modification, transcriptional regulation and post-translational modification. LKB1 dowcnstream pathways mainly include AMPK, microtubule affinity regulating kinase (MARK), salt-inducible kinase (SIK), sucrose non-fermenting protein-related kinase (SNRK) and brain selective kinase (BRSK) signalings, etc. This review, therefore, mainly discusses recent studies about the expression, regulation, downstream signaling and cancer suppressive function of LKB1, which can be helpful for better understanding of this molecular and its significance in cancers. PMID:25244018

  3. Changing partners at the dance

    PubMed Central

    Kallal, Lara E.; Biron, Christine A.

    2013-01-01

    Differential use of cellular and molecular components shapes immune responses, but understanding of how these are regulated to promote defense and health during infections is still incomplete. Examples include signaling from members of the Janus activated kinase-signal transducer and activator of transcription (JAK-STAT) cytokine family. Following receptor stimulation, individual JAK-STAT cytokines have preferences for particular key STAT molecules to lead to specific cellular responses. Certain of these cytokines, however, can conditionally activate alternative STATs as well as elicit pleiotropic and paradoxical effects. Studies examining basal and infection conditions are revealing intrinsic and induced cellular differences in various intracellular STAT concentrations to control the biological consequences of cytokine exposure. The system can be likened to changing partners at a dance based on competition and relative availability, and sets a framework for understanding the particular conditions promoting subset biological functions of cytokines as needed during evolving immune responses to infections. PMID:24058795

  4. TEC protein tyrosine kinase is involved in the Erk signaling pathway induced by HGF

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li, Feifei; Jiang, Yinan; Zheng, Qiping

    Research highlights: {yields} TEC is rapidly tyrosine-phosphorylated and activated by HGF-stimulation in vivo or after partial hepatectomy in mice. {yields} TEC enhances the activity of Elk and serum response element (SRE) in HGF signaling pathway in hepatocyte. {yields} TEC promotes hepatocyte proliferation through the Erk-MAPK pathway. -- Abstract: Background/aims: TEC, a member of the TEC family of non-receptor type protein tyrosine kinases, has recently been suggested to play a role in hepatocyte proliferation and liver regeneration. This study aims to investigate the putative mechanisms of TEC kinase regulation of hepatocyte differentiation, i.e. to explore which signaling pathway TEC is involvedmore » in, and how TEC is activated in hepatocyte after hepatectomy and hepatocyte growth factor (HGF) stimulation. Methods: We performed immunoprecipitation (IP) and immunoblotting (IB) to examine TEC tyrosine phosphorylation after partial hepatectomy in mice and HGF stimulation in WB F-344 hepatic cells. The TEC kinase activity was determined by in vitro kinase assay. Reporter gene assay, antisense oligonucleotide and TEC dominant negative mutant (TEC{sup KM}) were used to examine the possible signaling pathways in which TEC is involved. The cell proliferation rate was evaluated by {sup 3}H-TdR incorporation. Results: TEC phosphorylation and kinase activity were increased in 1 h after hepatectomy or HGF treatment. TEC enhanced the activity of Elk and serum response element (SRE). Inhibition of MEK1 suppressed TEC phosphorylation. Blocking TEC activity dramatically decreased the activation of Erk. Reduced TEC kinase activity also suppressed the proliferation of WB F-344 cells. These results suggest TEC is involved in the Ras-MAPK pathway and acts between MEK1 and Erk. Conclusions: TEC promotes hepatocyte proliferation and regeneration and is involved in HGF-induced Erk signaling pathway.« less

  5. The protein kinase Pelle mediates feedback regulation in the Drosophila Toll signaling pathway.

    PubMed

    Towb, P; Bergmann, A; Wasserman, S A

    2001-12-01

    Dorsoventral polarity in the Drosophila embryo is established through a signal transduction cascade triggered in ventral and ventrolateral regions. Activation of a transmembrane receptor, Toll, leads to localized recruitment of the adaptor protein Tube and protein kinase Pelle. Signaling through these components directs degradation of the IkappaB-like inhibitor Cactus and nuclear translocation of the Rel protein Dorsal. Here we show through confocal immunofluorescence microscopy that Pelle functions to downregulate the signal-dependent relocalization of Tube. Inactivation of the Pelle kinase domain, or elimination of the Tube-Pelle interaction, dramatically increases Tube recruitment to the ventral plasma membrane in regions of active signaling. We also characterize a large collection of pelle alleles, identifying the molecular lesions in these alleles and their effects on Pelle autophosphorylation, Tube phosphorylation and Tube relocalization. Our results point to a mechanism operating to modulate the domain or duration of signaling downstream from Tube and Pelle.

  6. Pan-SRC kinase inhibition blocks B-cell receptor oncogenic signaling in non-Hodgkin lymphoma.

    PubMed

    Battistello, Elena; Katanayeva, Natalya; Dheilly, Elie; Tavernari, Daniele; Donaldson, Maria C; Bonsignore, Luca; Thome, Margot; Christie, Amanda L; Murakami, Mark A; Michielin, Olivier; Ciriello, Giovanni; Zoete, Vincent; Oricchio, Elisa

    2018-05-24

    In diffuse large B-cell lymphoma (DLBCL), activation of the B-cell receptor (BCR) promotes multiple oncogenic signals, which are essential for tumor proliferation. Inhibition of the Bruton's tyrosine kinase (BTK), a BCR downstream target, is therapeutically effective only in a subgroup of patients with DLBCL. Here, we used lymphoma cells isolated from patients with DLBCL to measure the effects of targeted therapies on BCR signaling and to anticipate response. In lymphomas resistant to BTK inhibition, we show that blocking BTK activity enhanced tumor dependencies from alternative oncogenic signals downstream of the BCR, converging on MYC upregulation. To completely ablate the activity of the BCR, we genetically and pharmacologically repressed the activity of the SRC kinases LYN, FYN, and BLK, which are responsible for the propagation of the BCR signal. Inhibition of these kinases strongly reduced tumor growth in xenografts and cell lines derived from patients with DLBCL independent of their molecular subtype, advancing the possibility to be relevant therapeutic targets in broad and diverse groups of DLBCL patients. © 2018 by The American Society of Hematology.

  7. Dynamic Modelling of Embeddable Piezoceramic Transducers

    PubMed Central

    Li, Xu; Li, Hongnan; Wang, Zhijie; Song, Gangbing

    2017-01-01

    Embedded Lead Zirconate Titanate (PZT) transducers have been widely used in research related to monitoring the health status of concrete structures. This paper presents a dynamic model of an embeddable PZT transducer with a waterproof layer and a protecting layer. The proposed model is verified by finite-element method (FEM). Based on the proposed model, the factors influencing the dynamic property of the embeddable PZT transducers, which include the material and thickness of the protecting layer, the material and thickness of the waterproof layer, and the thickness of the PZT, are analyzed. These analyses are further validated by a series of dynamic stress transfer experiments on embeddable PZT transducers. The results show that the excitation frequency can significantly affect the stress transfer of the PZT transducer in terms of both amplitude and signal phase. The natural frequency in the poling direction for the PZT transducer is affected by the material properties and the thickness of the waterproof and protecting layers. The studies in this paper will provide a scientific basis to design embeddable PZT transducers with special functions. PMID:29206150

  8. Resonant capacitive MEMS acoustic emission transducers

    NASA Astrophysics Data System (ADS)

    Ozevin, D.; Greve, D. W.; Oppenheim, I. J.; Pessiki, S. P.

    2006-12-01

    We describe resonant capacitive MEMS transducers developed for use as acoustic emission (AE) detectors, fabricated in the commercial three-layer polysilicon surface micromachining process (MUMPs). The 1 cm square device contains six independent transducers in the frequency range between 100 and 500 kHz, and a seventh transducer at 1 MHz. Each transducer is a parallel plate capacitor with one plate free to vibrate, thereby causing a capacitance change which creates an output signal in the form of a current under a dc bias voltage. With the geometric proportions we employed, each transducer responds with two distinct resonant frequencies. In our design the etch hole spacing was chosen to limit squeeze film damping and thereby produce an underdamped vibration when operated at atmospheric pressure. Characterization experiments obtained by capacitance and admittance measurements are presented, and transducer responses to physically simulated AE source are discussed. Finally, we report our use of the device to detect acoustic emissions associated with crack initiation and growth in weld metal.

  9. Instrument For Simulation Of Piezoelectric Transducers

    NASA Technical Reports Server (NTRS)

    Mcnichol, Randal S.

    1996-01-01

    Electronic instrument designed to simulate dynamic output of integrated-circuit piezoelectric acceleration or pressure transducer. Operates in conjunction with external signal-conditioning circuit, generating square-wave signal of known amplitude for use in calibrating signal-conditioning circuit. Instrument also useful as special-purpose square-wave generator in other applications.

  10. Janus dendrimersomes coassembled from fluorinated, hydrogenated, and hybrid Janus dendrimers as models for cell fusion and fission.

    PubMed

    Xiao, Qi; Sherman, Samuel E; Wilner, Samantha E; Zhou, Xuhao; Dazen, Cody; Baumgart, Tobias; Reed, Ellen H; Hammer, Daniel A; Shinoda, Wataru; Klein, Michael L; Percec, Virgil

    2017-08-22

    A three-component system of Janus dendrimers (JDs) including hydrogenated, fluorinated, and hybrid hydrogenated-fluorinated JDs are reported to coassemble by film hydration at specific ratios into an unprecedented class of supramolecular Janus particles (JPs) denoted Janus dendrimersomes (JDSs). They consist of a dumbbell-shaped structure composed of an onion-like hydrogenated vesicle and an onion-like fluorinated vesicle tethered together. The synthesis of dye-tagged analogs of each JD component enabled characterization of JDS architectures with confocal fluorescence microscopy. Additionally, a simple injection method was used to prepare submicron JDSs, which were imaged with cryogenic transmission electron microscopy (cryo-TEM). As reported previously, different ratios of the same three-component system yielded a variety of structures including homogenous onion-like vesicles, core-shell structures, and completely self-sorted hydrogenated and fluorinated vesicles. Taken together with the JDSs reported herein, a self-sorting pathway is revealed as a function of the relative concentration of the hybrid JD, which may serve to stabilize the interface between hydrogenated and fluorinated bilayers. The fission-like pathway suggests the possibility of fusion and fission processes in biological systems that do not require the assistance of proteins but instead may result from alterations in the ratios of membrane composition.

  11. Phosphoglycerolipids are master players in plant hormone signal transduction.

    PubMed

    Janda, Martin; Planchais, Severine; Djafi, Nabila; Martinec, Jan; Burketova, Lenka; Valentova, Olga; Zachowski, Alain; Ruelland, Eric

    2013-06-01

    Phosphoglycerolipids are essential structural constituents of membranes and some also have important cell signalling roles. In this review, we focus on phosphoglycerolipids that are mediators in hormone signal transduction in plants. We first describe the structures of the main signalling phosphoglycerolipids and the metabolic pathways that generate them, namely the phospholipase and lipid kinase pathways. In silico analysis of Arabidopsis transcriptome data provides evidence that the genes encoding the enzymes of these pathways are transcriptionally regulated in responses to hormones, suggesting some link with hormone signal transduction. The involvement of phosphoglycerolipid signalling in the early responses to abscisic acid, salicylic acid and auxins is then detailed. One of the most important signalling lipids in plants is phosphatidic acid. It can activate or inactivate protein kinases and/or protein phosphatases involved in hormone signalling. It can also activate NADPH oxidase leading to the production of reactive oxygen species. We will interrogate the mechanisms that allow the activation/deactivation of the lipid pathways, in particular the roles of G proteins and calcium. Mediating lipids thus appear as master players of cell signalling, modulating, if not controlling, major transducing steps of hormone signals.

  12. Curcumin Stimulates Proliferation of Spinal Cord Neural Progenitor Cells via a Mitogen-Activated Protein Kinase Signaling Pathway

    PubMed Central

    Son, Sihoon; Cho, Dae-Chul; Kim, Hye-Jeong; Sung, Joo-Kyung; Bae, Jae-Sung

    2014-01-01

    Objective The aims of our study are to evaluate the effect of curcumin on spinal cord neural progenitor cell (SC-NPC) proliferation and to clarify the mechanisms of mitogen-activated protein (MAP) kinase signaling pathways in SC-NPCs. Methods We established cultures of SC-NPCs, extracted from the spinal cord of Sprague-Dawley rats weighing 250 g to 350 g. We measured proliferation rates of SC-NPCs after curcumin treatment at different dosage. The immuno-blotting method was used to evaluate the MAP kinase signaling protein that contains extracellular signal-regulated kinases (ERKs), p38, c-Jun NH2-terminal kinases (JNKs) and β-actin as the control group. Results Curcumin has a biphasic effect on SC-NPC proliferation. Lower dosage (0.1, 0.5, 1 µM) of curcumin increased SC-NPC proliferation. However, higher dosage decreased SC-NPC proliferation. Also, curcumin stimulates proliferation of SC-NPCs via the MAP kinase signaling pathway, especially involving the p-ERK and p-38 protein. The p-ERK protein and p38 protein levels varied depending on curcumin dosage (0.5 and 1 µM, p<0.05). Conclusion Curcumin can stimulate proliferation of SC-NPCs via ERKs and the p38 signaling pathway in low concentrations. PMID:25289117

  13. Peficitinib, an Oral Janus Kinase Inhibitor, in Moderate-to-Severe Ulcerative Colitis: Results From a Randomized, Phase 2 Study.

    PubMed

    Sands, Bruce E; Sandborn, William J; Feagan, Brian G; Lichtenstein, Gary R; Zhang, Hongyan; Strauss, Richard; Szapary, Philippe; Johanns, Jewel; Panes, Julian; Vermeire, Severine; O'Brien, Christopher D; Yang, Zijiang; Bertelsen, Kirk; Marano, Colleen

    2018-06-15

    Janus kinase (JAK) inhibitors have shown efficacy in ulcerative colitis (UC). We studied the dose-response, efficacy, and safety of peficitinib, an oral JAK inhibitor, in patients with moderate-to-severe UC. In this Phase 2b, dose-ranging trial, we evaluated peficitinib at 25mg once daily (qd), 75mg qd, 150mg qd, and 75mg twice daily versus placebo for efficacy and safety in 219 patients with moderate-to-severe UC. The primary outcome was peficitinib dose-response at Week 8 with response assessed using Mayo score change from baseline. Secondary endpoints were clinical response, clinical remission, mucosal healing, change from baseline in Inflammatory Bowel Disease Questionnaire (IBDQ), and normalization of inflammatory biomarkers at Week 8; other secondary endpoints were treatment response through Week 16 and through Week 32 for patients in clinical response at Week 8. Safety was assessed through Week 36 or 4 weeks after the last dose. A statistically significant peficitinib dose-response was not demonstrated at Week 8, although a numerically greater proportion of patients receiving peficitinib ≥75mg qd achieved clinical response, remission, and mucosal healing at Week 8, supported by IBDQ improvement and inflammatory biomarker normalization. Treatment-emergent adverse event (TEAE) rates reported through Week 8 and the final safety visit were higher in the combined peficitinib group than placebo; patients receiving doses of ≥75mg qd peficitinib reported TEAEs more frequently. While no dose-response in patients with moderate-to-severe UC was demonstrated with peficitinib, evidence of efficacy was suggested at doses ≥75mg qd. The safety profile of peficitinib was consistent with current information. ClinicalTrials.gov NCT01959282.

  14. Identification and characterization of metabolites of ASP015K, a novel oral Janus kinase inhibitor, in rats, chimeric mice with humanized liver, and humans.

    PubMed

    Nakada, Naoyuki; Oda, Kazuo

    2015-01-01

    1. Here, we elucidated the structure of metabolites of novel oral Janus kinase inhibitor ASP015K in rats and humans and evaluated the predictability of human metabolites using chimeric mice with humanized liver (PXB mice). 2. Rat biological samples collected after oral dosing of (14)C-labelled ASP015K were examined using a liquid chromatography-radiometric detector and mass spectrometer (LC-RAD/MS). The molecular weight of metabolites in human and the liver chimeric mouse biological samples collected after oral dosing of non-labelled ASP015K was also investigated via LC-MS. Metabolites were also isolated from rat bile samples and analyzed using nuclear magnetic resonance. 3. Metabolic pathways of ASP015K in rats and humans were found to be glucuronide conjugation, methyl conjugation, sulfate conjugation, glutathione conjugation, hydroxylation of the adamantane ring and N-oxidation of the 1H-pyrrolo[2,3-b]pyridine ring. The main metabolite of ASP015K in rats was the glucuronide conjugate, while the main metabolite in humans was the sulfate conjugate. Given that human metabolites were produced by human hepatocytes in chimeric mice with humanized liver, this human model mouse was believed to be useful in predicting the human metabolic profile of various drug candidates.

  15. Interfacial preparation and optical transmission surface plasmon resonance of Janus metamaterials membrane

    NASA Astrophysics Data System (ADS)

    Du, Yixuan; Zhang, Xiaowei; Li, Yunbo

    2018-01-01

    Janus metamaterials membrane had been fabricated using self-assembly strategy at the oil/water interface with thiol-terminated polymers. Janus metamaterials membrane exhibits a characteristic surface plasmon absorption band, in which the peak position is sensitive to the addition of polymer. The optical transmission surface plasmon resonance (T-SPR) peak has a blue shift at the visible region with addition of thiol-terminated polystyrene (PS-SH). With thiol-terminated poly (ethylene glycol) (PEG-SH) attachment onto the surface side of gold nanoparticles (AuNPs), the T-SPR band has a successive blue shift. One surprising thing is that it has a flat terrace on T-SPR band from 580 to 740 nm. In addition, The T-SPR of Janus metamaterials membrane dramatically changed with the addition PS-SH when the PEG-SH was capped on the opposite side. The morphologies of AuNPs membrane and Janus metamaterials membrane support the above mentioned result of SPR. In virtue of tunable SPR band, the Janus metamaterials membrane has great potential application in science-based design of optical sensing sensors and surface-enhanced optic sensitive detection.

  16. Sustained activation of c-Jun N-terminal and extracellular signal-regulated kinases in port-wine stain blood vessels.

    PubMed

    Tan, Wenbin; Chernova, Margarita; Gao, Lin; Sun, Victor; Liu, Huaxu; Jia, Wangcun; Langer, Stephanie; Wang, Gang; Mihm, Martin C; Nelson, J Stuart

    2014-11-01

    Port-wine stain (PWS) is a congenital, progressive vascular malformation but the pathogenesis remains incompletely understood. We sought to investigate the activation status of various kinases, including extracellular signal-regulated kinase, c-Jun N-terminal kinase, AKT, phosphatidylinositol 3-kinase, P70 ribosomal S6 kinase, and phosphoinositide phospholipase C γ subunit, in PWS biopsy tissues. Immunohistochemistry was performed on 19 skin biopsy samples from 11 patients with PWS. c-Jun N-terminal kinase, extracellular signal-regulated kinase, and P70 ribosomal S6 kinase in pediatric and adult PWS blood vessels were consecutively activated. Activation of AKT and phosphatidylinositol 3-kinase was found in many adult hypertrophic PWS blood vessels but not in infants. Phosphoinositide phospholipase C γ subunit showed strong activation in nodular PWS blood vessels. Infantile PWS sample size was small. Our data suggest a subsequent activation profile of various kinases during different stages of PWS: (1) c-Jun N-terminal and extracellular signal-regulated kinases are firstly and consecutively activated in all PWS tissues, which may contribute to both the pathogenesis and progressive development of PWS; (2) AKT and phosphatidylinositol 3-kinase are subsequently activated, and are involved in the hypertrophic development of PWS blood vessels; and (3) phosphoinositide phospholipase C γ subunit is activated in the most advanced stage of PWS and may participate in nodular formation. Copyright © 2014 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  17. Distinct and Overlapping Functions of TEC Kinase and BTK in B Cell Receptor Signaling.

    PubMed

    de Bruijn, Marjolein J W; Rip, Jasper; van der Ploeg, Esmee K; van Greuningen, Lars W; Ta, Van T B; Kil, Laurens P; Langerak, Anton W; Rimmelzwaan, Guus F; Ellmeier, Wilfried; Hendriks, Rudi W; Corneth, Odilia B J

    2017-04-15

    The Tec tyrosine kinase is expressed in many cell types, including hematopoietic cells, and is a member of the Tec kinase family that also includes Btk. Although the role of Btk in B cells has been extensively studied, the role of Tec kinase in B cells remains largely unclear. It was previously shown that Tec kinase has the ability to partly compensate for loss of Btk activity in B cell differentiation, although the underlying mechanism is unknown. In this study, we confirm that Tec kinase is not essential for normal B cell development when Btk is present, but we also found that Tec-deficient mature B cells showed increased activation, proliferation, and survival upon BCR stimulation, even in the presence of Btk. Whereas Tec deficiency did not affect phosphorylation of phospholipase Cγ or Ca 2+ influx, it was associated with significantly increased activation of the intracellular Akt/S6 kinase signaling pathway upon BCR and CD40 stimulation. The increased S6 kinase phosphorylation in Tec-deficient B cells was dependent on Btk kinase activity, as ibrutinib treatment restored pS6 to wild-type levels, although Btk protein and phosphorylation levels were comparable to controls. In Tec-deficient mice in vivo, B cell responses to model Ags and humoral immunity upon influenza infection were enhanced. Moreover, aged mice lacking Tec kinase developed a mild autoimmune phenotype. Taken together, these data indicate that in mature B cells, Tec and Btk may compete for activation of the Akt signaling pathway, whereby the activating capacity of Btk is limited by the presence of Tec kinase. Copyright © 2017 by The American Association of Immunologists, Inc.

  18. Inhibiting Src family tyrosine kinase activity blocks glutamate signalling to ERK1/2 and Akt/PKB but not JNK in cultured striatal neurones.

    PubMed

    Crossthwaite, Andrew J; Valli, Haseeb; Williams, Robert J

    2004-03-01

    Glutamate receptor activation of mitogen-activated protein (MAP) kinase signalling cascades has been implicated in diverse neuronal functions such as synaptic plasticity, development and excitotoxicity. We have previously shown that Ca2+-influx through NMDA receptors in cultured striatal neurones mediates the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and Akt/protein kinase B (PKB) through a phosphatidylinositol 3-kinase (PI 3-kinase)-dependent pathway. Exposing neurones to the Src family tyrosine kinase inhibitor PP2, but not the inactive analogue PP3, inhibited NMDA receptor-induced phosphorylation of ERK1/2 and Akt/PKB in a concentration-dependent manner, and reduced cAMP response element-binding protein (CREB) phosphorylation. To establish a link between Src family tyrosine kinase-mediated phosphorylation and PI 3-kinase signalling, affinity precipitation experiments were performed with the SH2 domains of the PI 3-kinase regulatory subunit p85. This revealed a Src-dependent phosphorylation of a focal adhesion kinase (FAK)-p85 complex on glutamate stimulation. Demonstrating that PI3-kinase is not ubiquitously involved in NMDA receptor signal transduction, the PI 3-kinase inhibitors wortmannin and LY294002 did not prevent NMDA receptor Ca2+-dependent phosphorylation of c-Jun N-terminal kinase 1/2 (JNK1/2). Further, inhibiting Src family kinases increased NMDA receptor-dependent JNK1/2 phosphorylation, suggesting that Src family kinase-dependent cascades may physiologically limit signalling to JNK. These results demonstrate that Src family tyrosine kinases and PI3-kinase are pivotal regulators of NMDA receptor signalling to ERK/Akt and JNK in striatal neurones.

  19. Redox and Src family kinase signaling control leukocyte wound attraction and neutrophil reverse migration.

    PubMed

    Tauzin, Sebastien; Starnes, Taylor W; Becker, Francisco Barros; Lam, Pui-ying; Huttenlocher, Anna

    2014-12-08

    Tissue damage induces early recruitment of neutrophils through redox-regulated Src family kinase (SFK) signaling in neutrophils. Redox-SFK signaling in epithelium is also necessary for wound resolution and tissue regeneration. How neutrophil-mediated inflammation resolves remains unclear. In this paper, we studied the interactions between macrophages and neutrophils in response to tissue damage in zebrafish and found that macrophages contact neutrophils and induce resolution via neutrophil reverse migration. We found that redox-SFK signaling through p22phox and Yes-related kinase is necessary for macrophage wound attraction and the subsequent reverse migration of neutrophils. Importantly, macrophage-specific reconstitution of p22phox revealed that macrophage redox signaling is necessary for neutrophil reverse migration. Thus, redox-SFK signaling in adjacent tissues is essential for coordinated leukocyte wound attraction and repulsion through pathways that involve contact-mediated guidance. © 2014 Tauzin et al.

  20. Selective enhancement of radiation response of herpes simplex virus thymidine kinase transduced 9L gliosarcoma cells in vitro and in vivo by antiviral agents

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kim, Jae Ho; Kim, Sang Hie; Kolozsvary, A.

    1995-11-01

    The purpose of this investigation was to demonstrate in a well-characterized tumor model that the radiosensitivity of tumor cells transduced with a herpes simplex virus thymidine kinase gene (HS-tk) would be selectively enhanced by antiviral agents. Rat 9L gliosarcoma cells transduced with a retroviral vector containing an HS-tk gene, 9L-tk cells were exposed to various doses or irradiation under either in vitro or in vivo conditions. The radiation sensitizing potential of two antiviral drugs, bromovinyl deoxyuridine (BVdU) and dihydroxymethyl ethyl methyl guanine (acyclovir), was evaluated in vitro. The radiosensitizing ability of BVdU was also evaluated with a 9L-tk tumor growingmore » in the rat brain. Tumors growing in the right hemisphere of rat brains were irradiated stereotactically with single-dose irradiation. The radiation response of 9L-tk cells was selectively enhanced by antiviral agents relative to nontransduced cells. In the cell culture, when a 24-h drug exposure (20 {mu}g/ml) preceded radiation, the sensitizer enhancement ratio (SER) for BVdU and acyclovir was 1.4 {plus_minus} 0.1 and 1.3 {plus_minus} 0.1, respectively. Exposure of cells to 10 {mu}g/ml acyclovir for two 24-h periods both pre- and postirradiation resulted in a SER of 1.6 {plus_minus} 0.1. In vivo, a significant increase in median survival time of rats with 9L-tk tumors was found when BVdU was administered prior to single-dose irradiation relative to the survival time of similar rats receiving radiation alone. An antiviral agent can enhance cell killing by radiation with selective action in cells transduced with the herpes simplex virus thymidine kinase gene. The results suggest that the three-pronged therapy of HS-tk gene transduction, systemically administered antiviral drug, and stereotactically targeted radiation therapy will improve the effectiveness of radiation therapy for the treatment of radioresistant tumors. 25 refs., 6 figs.« less

  1. Lyn tyrosine kinase promotes silencing of ATM-dependent checkpoint signaling during recovery from DNA double-strand breaks

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fukumoto, Yasunori, E-mail: fukumoto@faculty.chiba-u.jp; Kuki, Kazumasa; Morii, Mariko

    2014-09-26

    Highlights: • Inhibition of Src family kinases decreased γ-H2AX signal. • Inhibition of Src family increased ATM-dependent phosphorylation of Chk2 and Kap1. • shRNA-mediated knockdown of Lyn increased phosphorylation of Kap1 by ATM. • Ectopic expression of Src family kinase suppressed ATM-mediated Kap1 phosphorylation. • Src is involved in upstream signaling for inactivation of ATM signaling. - Abstract: DNA damage activates the DNA damage checkpoint and the DNA repair machinery. After initial activation of DNA damage responses, cells recover to their original states through completion of DNA repair and termination of checkpoint signaling. Currently, little is known about the processmore » by which cells recover from the DNA damage checkpoint, a process called checkpoint recovery. Here, we show that Src family kinases promote inactivation of ataxia telangiectasia mutated (ATM)-dependent checkpoint signaling during recovery from DNA double-strand breaks. Inhibition of Src activity increased ATM-dependent phosphorylation of Chk2 and Kap1. Src inhibition increased ATM signaling both in G2 phase and during asynchronous growth. shRNA knockdown of Lyn increased ATM signaling. Src-dependent nuclear tyrosine phosphorylation suppressed ATM-mediated Kap1 phosphorylation. These results suggest that Src family kinases are involved in upstream signaling that leads to inactivation of the ATM-dependent DNA damage checkpoint.« less

  2. MicroRNA-9 Inhibits NLRP3 Inflammasome Activation in Human Atherosclerosis Inflammation Cell Models through the JAK1/STAT Signaling Pathway.

    PubMed

    Wang, Yue; Han, Zhihua; Fan, Yuqi; Zhang, Junfeng; Chen, Kan; Gao, Lin; Zeng, Huasu; Cao, Jiatian; Wang, Changqian

    2017-01-01

    MicroRNA-9 (miR-9) is involved in inflammatory reaction in atherosclerosis; however, its function and regulatory mechanisms remain unclear. We aimed to uncover the exact roles of miR-9 and downstream signaling pathways using in vitro human atherosclerosis models. We used oxidized low-density lipoprotein (oxLDL)-stimulated human THP-1 derived macrophages, oxLDL-stimulated human primary peripheral blood monocytes and lipopolysaccharides (LPS) or Alum-stimulated human THP-1 derived macrophages as in vitro atherosclerosis inflammation models. Transient transfection of over-expression vectors, small interference RNAs (siRNAs) or antisense oligonucleotides was used to regulate intracellular protein or miR-9 levels. Cell responses and signal transduction were detected by multiple assays including Western blotting, enzyme-linked immunosorbent assay (ELISA) and luciferase reporter assay. MiR-9 inhibited while anti-miR-9 antisense oligonucleotides induced interleukin-1 beta (IL-1β) and NLRP3 inflammasome activation in all in vitro models. Janus kinase 1 (JAK1) and matrix metalloproteinase 13 (MMP-13) were identified as the target genes of miR-9. In oxLDL-stimulated human THP-1 derived macrophages, knockdown of JAK1 by siRNA blocked the phosphorylation of signal transducer and activator of transcription 1 (STAT1) and mimicked the effects of miR-9. In the same model, JAK1 knockdown blocked the phosphorylation of NF-κB p65 in the nuclei and the phosphorylation of NF-κB IκBα in the cytoplasm. Our study demonstrated that miR-9 could inhibit activation of the NLRP3 inflammasome and attenuate atherosclerosis-related inflammation, likely through the JAK1/STAT1 signaling pathway. Therefore, miR-9 may serve as a potential therapeutic target for atherosclerosis. © 2017 The Author(s)Published by S. Karger AG, Basel.

  3. IL-8 induces miR-424-5p expression and modulates SOCS2/STAT5 signaling pathway in oral squamous cell carcinoma.

    PubMed

    Peng, Hsuan-Yu; Jiang, Shih-Sheng; Hsiao, Jenn-Ren; Hsiao, Michael; Hsu, Yuan-Ming; Wu, Guan-Hsun; Chang, Wei-Min; Chang, Jang-Yang; Jin, Shiow-Lian Catherine; Shiah, Shine-Gwo

    2016-06-01

    Suppressor of cytokine signaling (SOCS) proteins are negative feedback regulators of the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway. Dysregulation of SOCS protein expression in cancers can be one of the mechanisms that maintain STAT activation, but this mechanism is still poorly understood in oral squamous cell carcinoma (OSCC). Here, we report that SOCS2 protein is significantly downregulated in OSCC patients and its levels are inversely correlated with miR-424-5p expression. We identified the SOCS2 protein, which modulates STAT5 activity, as a direct target of miR-424-5p. The miR-424-5p-induced STAT5 phosphorylation, matrix metalloproteinases (MMPs) expression, and cell migration and invasion were blocked by SOCS2 restoration, suggesting that miR-424-5p exhibits its oncogenic activity through negatively regulating SOCS2 levels. Furthermore, miR-424-5p expression could be induced by the cytokine IL-8 primarily through enhancing STAT5 transcriptional activity rather than NF-κB signaling. Antagomir-mediated inactivation of miR-424-5p prevented the IL-8-induced cell migration and invasion, indicating that miR-424-5p is required for IL-8-induced cellular invasiveness. Taken together, these data indicate that STAT5-dependent expression of miR-424-5p plays an important role in mediating IL-8/STAT5/SOCS2 feedback loop, and scavenging miR-424-5p function using antagomir may have therapeutic potential for the treatment of OSCC. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  4. Modulation of skeletal muscle fiber type by mitogen-activated protein kinase signaling.

    PubMed

    Shi, Hao; Scheffler, Jason M; Pleitner, Jonathan M; Zeng, Caiyun; Park, Sungkwon; Hannon, Kevin M; Grant, Alan L; Gerrard, David E

    2008-08-01

    Skeletal muscle is composed of diverse fiber types, yet the underlying molecular mechanisms responsible for this diversification remain unclear. Herein, we report that the extracellular signal-regulated kinase (ERK) 1/2 pathway, but not p38 or c-Jun NH(2)-terminal kinase (JNK), is preferentially activated in fast-twitch muscles. Pharmacological blocking of ERK1/2 pathway increased slow-twitch fiber type-specific reporter activity and repressed those associated with the fast-twitch fiber phenotype in vitro. Overexpression of a constitutively active ERK2 had an opposite effect. Inhibition of ERK signaling in cultured myotubes increased slow-twitch fiber-specific protein accumulation while repressing those characteristic of fast-twitch fibers. Overexpression of MAP kinase phosphatase-1 (MKP1) in mouse and rat muscle fibers containing almost exclusively type IIb or IIx fast myosin heavy chain (MyHC) isoforms induced de novo synthesis of the slower, more oxidative type IIa and I MyHCs in a time-dependent manner. Conversion to the slower phenotype was confirmed by up-regulation of slow reporter gene activity and down-regulation of fast reporter activities in response to forced MKP1 expression in vivo. In addition, activation of ERK2 signaling induced up-regulation of fast-twitch fiber program in soleus. These data suggest that the MAPK signaling, most likely the ERK1/2 pathway, is necessary to preserve the fast-twitch fiber phenotype with a concomitant repression of slow-twitch fiber program.

  5. Topical N-Acetylcysteine Accelerates Wound Healing in Vitro and in Vivo via the PKC/Stat3 Pathway

    PubMed Central

    Tsai, Min-Ling; Huang, Hui-Pei; Hsu, Jeng-Dong; Lai, Yung-Rung; Hsiao, Yu-Ping; Lu, Fung-Jou; Chang, Horng-Rong

    2014-01-01

    N-Acetylcysteine (Nac) is an antioxidant administered in both oral and injectable forms. In this study, we used Nac topically to treat burn wounds in vitro and in vivo to investigate mechanisms of action. In vitro, we monitored glutathione levels, cell proliferation, migration, scratch-wound healing activities and the epithelialization-related proteins, matrixmetalloproteinase-1 (MMP-1) and proteins involved in regulating the expression of MMP-1 in CCD-966SK cells treated with Nac. Various Nac concentrations (0.1, 0.5, and 1.0 mM) increased glutathione levels, cell viability, scratch-wound healing activities and migration abilities of CCD-966SK cells in a dose-dependent manner. The MMP-1 expression of CCD-966SK cells treated with 1.0 mM Nac for 24 h was significantly increased. Levels of phosphatidylinositol 3-kinase (PI3K), protein kinase C (PKC), janus kinase 1 (Jak1), signal transducer and activator of transcription 3 (Stat3), c-Fos and Jun, but not extracellular signal-regulated protein kinases 1 and 2 (Erk1/2), were also significantly increased in a dose-dependent manner compared to the controls. In addition, Nac induced collagenous expression of MMP-1 via the PKC/Stat3 signaling pathway. In vivo, a burn wound healing rat model was applied to assess the stimulation activity and histopathological effects of Nac, with 3.0% Nac-treated wounds being found to show better characteristics on re-epithelialization. Our results demonstrated that Nac can potentially promote wound healing activity, and may be a promising drug to accelerate burn wound healing. PMID:24798751

  6. Luteinizing hormone stimulates mammalian target of rapamycin signaling in bovine luteal cells via pathways independent of AKT and mitogen-activated protein kinase: modulation of glycogen synthase kinase 3 and AMP-activated protein kinase.

    PubMed

    Hou, Xiaoying; Arvisais, Edward W; Davis, John S

    2010-06-01

    LH stimulates the production of cAMP in luteal cells, which leads to the production of progesterone, a hormone critical for the maintenance of pregnancy. The mammalian target of rapamycin (MTOR) signaling cascade has recently been examined in ovarian follicles where it regulates granulosa cell proliferation and differentiation. This study examined the actions of LH on the regulation and possible role of the MTOR signaling pathway in primary cultures of bovine corpus luteum cells. Herein, we demonstrate that activation of the LH receptor stimulates the phosphorylation of the MTOR substrates ribosomal protein S6 kinase 1 (S6K1) and eukaryotic translation initiation factor 4E binding protein 1. The actions of LH were mimicked by forskolin and 8-bromo-cAMP. LH did not increase AKT or MAPK1/3 phosphorylation. Studies with pathway-specific inhibitors demonstrated that the MAPK kinase 1 (MAP2K1)/MAPK or phosphatidylinositol 3-kinase/AKT signaling pathways were not required for LH-stimulated MTOR/S6K1 activity. However, LH decreased the activity of glycogen synthase kinase 3Beta (GSK3B) and AMP-activated protein kinase (AMPK). The actions of LH on MTOR/S6K1 were mimicked by agents that modulated GSK3B and AMPK activity. The ability of LH to stimulate progesterone secretion was not prevented by rapamycin, a MTOR inhibitor. In contrast, activation of AMPK inhibited LH-stimulated MTOR/S6K1 signaling and progesterone secretion. In summary, the LH receptor stimulates a unique series of intracellular signals to activate MTOR/S6K1 signaling. Furthermore, LH-directed changes in AMPK and GSK3B phosphorylation appear to exert a greater impact on progesterone synthesis in the corpus luteum than rapamycin-sensitive MTOR-mediated events.

  7. Measurement of heart sounds with EMFi transducer.

    PubMed

    Kärki, Satu; Kääriäinen, Minna; Lekkala, Jukka

    2007-01-01

    A measurement system for heart sounds was implemented by using ElectroMechanical Film (EMFi). Heart sounds are produced by the vibrations of the cardiac structure. An EMFi transducer attached to the skin of the chest wall converts these mechanical vibrations into an electrical signal. Furthermore, the signal is amplified and transmitted to the computer. The data is analyzed with Matlab software. The low-frequency components of the measured signal (respiration and pulsation of the heart) are filtered out as well as the 50 Hz noise. Also the power spectral density (PSD) plot is computed. In test measurements, the signal was measured with respiration and by holding breath. From the filtered signal, the first (S1) and the second (S2) heart sound can be clearly seen in both cases. In addition, from the raw data signals the respiration frequency and the heart rate can be determined. In future applications, with the EMFi material it is possible to implement a plaster-like transducer measuring vital signals.

  8. Parathyroid hormone inhibition of Na{sup +}/H{sup +} exchanger 3 transcription: Intracellular signaling pathways and transcription factor expression

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Neri, Elida Adalgisa; Bezerra, Camila Nogueira Alves, E-mail: camilab@icb.usp.br; Queiroz-Leite, Gabriella Duarte

    2015-06-12

    The main transport mechanism of reabsorption of sodium bicarbonate and fluid in the renal proximal tubules involves Na{sup +}/H{sup +} exchanger 3 (NHE3), which is acutely and chronically downregulated by parathyroid hormone (PTH). Although PTH is known to exert an inhibitory effect on NHE3 expression and transcription, the molecular mechanisms involved remain unclear. Here, we demonstrated that, in opossum kidney proximal tubule (OKP) cells, PTH-induced inhibition of Nhe3 gene promoter occurs even in the core promoter that controls expression of the reporter gene. We found that inhibition of the protein kinase A (PKA) and Janus kinase/signal transducer and activator ofmore » transcription (JAK/STAT) pathways transformed PTH from an inhibitor of promoter activity into an activator of that same activity, as did point mutations in the EGR1, Sp1, and Sp3 binding consensus elements in the promoter. In nuclear extracts of PTH-treated OKP cells, we also observed increased expression of EGR1 mRNA and of some Sp3 isoforms. Electrophoretic mobility shift assay showed a supershift of the −61 to −42-bp probe with an anti-EGR1 antibody in PTH-treated cells, suggesting that EGR1 binding is relevant for the inhibitory activity of PTH. We conclude that PTH-induced inhibition of NHE3 transcription is related to higher EGR1 expression; to EGR1 binding to the proximal and core promoters; and to PKA and JAK/STAT pathway activation. This mechanism might be responsible, at least in part, for lower NHE3 expression and sodium reabsorption in renal proximal tubules in the presence of high PTH levels. - Highlights: • PTH regulation of Nhe3 promoter depends on EGR1 binding. • EGR1, PKA and JAK/STAT are involved in PTH inhibition of the Nhe3 promoter. • PTH alters expression of EGR1 and Sp3. • PTH inhibits the Nhe3 promoter by regulating PKA and JAK/STAT signaling.« less

  9. Intracellular pathways triggered by the selective FLT-1-agonist placental growth factor in vascular smooth muscle cells exposed to hypoxia.

    PubMed

    Bellik, Lydia; Vinci, Maria Cristina; Filippi, Sandra; Ledda, Fabrizio; Parenti, Astrid

    2005-10-01

    We have previously shown that hypoxia makes vascular smooth muscle cells (VSMCs) responsive to placental growth factor (PlGF) through the induction of functional fms-like tyrosine kinase (Flt-1) receptors. The aim of this study was to investigate the molecular mechanisms involved in the PlGF effects on proliferation and contraction of VSMCs previously exposed to hypoxia (3% O2). In cultured rat VSMCs exposed to hypoxia, PlGF increased the phosphorylation of protein kinase B (Akt), p38 and STAT3; activation of STAT3 was higher than that of other kinases. In agreement with this finding, the proliferation of hypoxia-treated VSMCs in response to PlGF was significantly impaired by the p38 and the phosphatidylinositol 3-kinase inhibitors SB202190 and LY294002, respectively, and was almost completely prevented by AG490, a janus tyrosine kinase (JAK)/signal transducer and activator of transcription (STAT) inhibitor. Since hypoxia was able to reverse the vasorelaxant effect of PlGF into a vasoconstrictor response, the mechanism of this latter effect was also investigated. Significant Flt-1 activity was measured in isolated preparations from rat aorta exposed to hypoxia. Inhibitors of mitogen-activated protein kinase kinase, Akt and STAT3 induced a modest inhibition of the vasoconstrictor response to PlGF, while the p38 inhibitor SB202190 markedly impaired the PlGF-induced contractile response. These effects were selectively mediated by Flt-1 without any involvement of foetal liver kinase-1 receptors. These data are the first evidence that different intracellular pathways activated by Flt-1 receptor in VSMCs are involved in diverse biological effects of PlGF: while mitogen activated protein kinase kinase/extracellular signal regulated kinase(1/2) and JAK/STAT play a role in VSMC proliferation, p38 is involved in VSMC contraction. These findings may highlight the role of PlGF in vascular pathology.

  10. The Envelope Glycoprotein of Friend Spleen Focus-Forming Virus Covalently Interacts with and Constitutively Activates a Truncated Form of the Receptor Tyrosine Kinase Stk

    PubMed Central

    Nishigaki, Kazuo; Thompson, Delores; Hanson, Charlotte; Yugawa, Takashi; Ruscetti, Sandra

    2001-01-01

    The Friend spleen focus-forming virus (SFFV) encodes a unique envelope glycoprotein, gp55, which allows erythroid cells to proliferate and differentiate in the absence of erythropoietin (Epo). SFFV gp55 has been shown to interact with the Epo receptor complex, causing constitutive activation of various signal-transducing molecules. When injected into adult mice, SFFV induces a rapid erythroleukemia, with susceptibility being determined by the host gene Fv-2, which was recently shown to be identical to the gene encoding the receptor tyrosine kinase Stk/Ron. Susceptible, but not resistant, mice encode not only full-length Stk but also a truncated form of the kinase, sf-Stk, which may mediate the biological effects of SFFV infection. To determine whether expression of SFFV gp55 leads to the activation of sf-Stk, we expressed sf-Stk, with or without SFFV gp55, in hematopoietic cells expressing the Epo receptor. Our data indicate that sf-Stk interacts with SFFV gp55 as well as gp55P, the biologically active form of the viral glycoprotein, forming disulfide-linked complexes. This covalent interaction, as well as noncovalent interactions with SFFV gp55, results in constitutive tyrosine phosphorylation of sf-Stk and its association with multiple tyrosine-phosphorylated signal-transducing molecules. In contrast, neither Epo stimulation in the absence of SFFV gp55 expression nor expression of a mutant of SFFV that cannot interact with sf-Stk was able to induce tyrosine phosphorylation of sf-Stk or its association with any signal-transducing molecules. Covalent interaction of sf-Stk with SFFV gp55 and constitutive tyrosine phosphorylation of sf-Stk can also be detected in an erythroleukemia cell line derived from an SFFV-infected mouse. Our results suggest that SFFV gp55 may mediate its biological effects in vivo by interacting with and activating a truncated form of the receptor tyrosine kinase Stk. PMID:11483734

  11. Peracetylated hydroxytyrosol, a new hydroxytyrosol derivate, attenuates LPS-induced inflammatory response in murine peritoneal macrophages via regulation of non-canonical inflammasome, Nrf2/HO1 and JAK/STAT signaling pathways.

    PubMed

    Montoya, Tatiana; Aparicio-Soto, Marina; Castejón, María Luisa; Rosillo, María Ángeles; Sánchez-Hidalgo, Marina; Begines, Paloma; Fernández-Bolaños, José G; Alarcón-de-la-Lastra, Catalina

    2018-03-18

    The present study was designed to investigate the anti-inflammatory effects of a new derivative of hydroxytyrosol (HTy), peracetylated hydroxytyrosol (Per-HTy), compared with its parent, HTy, on lipopolysaccharide (LPS)-stimulated murine macrophages as well as potential signaling pathways involved. In particular, we attempted to characterize the role of the inflammasome underlying Per-HTy possible anti-inflammatory effects. Isolated murine peritoneal macrophages were treated with HTy or its derivative in the presence or absence of LPS (5 μg/ml) for 18 h. Cell viability was determined using sulforhodamine B (SRB) assay. Nitric oxide (NO) production was analyzed by Griess method. Production of pro-inflammatory cytokines was evaluated by enzyme-linked immunosorbent assay (ELISA) and inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway (STAT3), haem oxigenase 1 (HO1), nuclear factor (erythroid-derived 2)-like 2 (Nrf2) expression and mitogen-activated protein kinases (MAPKs) activation was determined by Western blot. Per-HTy significantly reduced the levels of NO and pro-inflammatory cytokines as well as both COX-2 and iNOS expressions. Furthermore, Per-HTy treatment inhibited STAT3 and increased Nrf2 and HO1 protein levels in murine macrophages exposed to LPS. In addition, Per-HTy anti-inflammatory activity was related with an inhibition of non-canonical nucleotide binding domain (NOD)-like receptor (NLRP3) inflammasome pathways by decreasing pro-inflammatory interleukin (IL)-1β and IL-18 cytokine levels as consequence of regulation of cleaved caspase-11 enzyme. These results support that this new HTy derivative may offer a new promising nutraceutical therapeutic strategy in the management of inflammatory-related pathologies. Copyright © 2018. Published by Elsevier Inc.

  12. The secret life of kinases: insights into non-catalytic signalling functions from pseudokinases.

    PubMed

    Jacobsen, Annette V; Murphy, James M

    2017-06-15

    Over the past decade, our understanding of the mechanisms by which pseudokinases, which comprise ∼10% of the human and mouse kinomes, mediate signal transduction has advanced rapidly with increasing structural, biochemical, cellular and genetic studies. Pseudokinases are the catalytically defective counterparts of conventional, active protein kinases and have been attributed functions as protein interaction domains acting variously as allosteric modulators of conventional protein kinases and other enzymes, as regulators of protein trafficking or localisation, as hubs to nucleate assembly of signalling complexes, and as transmembrane effectors of such functions. Here, by categorising mammalian pseudokinases based on their known functions, we illustrate the mechanistic diversity among these proteins, which can be viewed as a window into understanding the non-catalytic functions that can be exerted by conventional protein kinases. © 2017 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

  13. Inhibitors of JAK-family kinases: an update on the patent literature 2013-2015, part 2.

    PubMed

    Kettle, Jason G; Åstrand, Annika; Catley, Matthew; Grimster, Neil P; Nilsson, Magnus; Su, Qibin; Woessner, Richard

    2017-02-01

    Janus kinases (JAKs) are a family of four enzymes; JAK1, JAK2, JAK3 and tyrosine kinase 2 (TYK2) that are critical in cytokine signalling and are strongly linked to both cancer and inflammatory diseases. There are currently two launched JAK inhibitors for the treatment of human conditions: tofacitinib for Rheumatoid arthritis (RA) and ruxolitinib for myeloproliferative neoplasms including intermediate or high risk myelofibrosis and polycythemia vera. Areas covered: This review covers patents claiming activity against one or more JAK family members in the period 2013-2015 inclusive, and covers 95 patents from 42 applicants, split over two parts. The authors have ordered recent patents according to the primary applicant's name, with part 2 covering J through Z. Expert opinion: Inhibition of JAK-family kinases is an area of growing interest, catalysed by the maturity of data on marketed inhibitors ruxolitinib and tofacitinib in late stage clinical trials. Many applicants are pursuing traditional fast-follower strategies around these inhibitors, with a range of chemical strategies adopted. The challenge will be to show sufficient differentiation to the originator compounds, since dose limiting toxicities with such agents appear to be on target and mechanism-related and also considering that such agents may be available as generic compounds by the time follower agents reach market.

  14. Inhibitors of JAK-family kinases: an update on the patent literature 2013-2015, part 1.

    PubMed

    Kettle, Jason G; Åstrand, Annika; Catley, Matthew; Grimster, Neil P; Nilsson, Magnus; Su, Qibin; Woessner, Richard

    2017-02-01

    Janus kinases (JAKs) are a family of four enzymes; JAK1, JAK2, JAK3 and tyrosine kinase 2 (TYK2) that are critical in cytokine signalling and are strongly linked to both cancer and inflammatory diseases. There are currently two launched JAK inhibitors for the treatment of human conditions: tofacitinib for Rheumatoid arthritis (RA) and ruxolitinib for myeloproliferative neoplasms including intermediate or high risk myelofibrosis and polycythemia vera. Areas covered: This review covers patents claiming activity against one or more JAK family members in the period 2013-2015 inclusive, and covers 95 patents from 42 applicants, split over two parts. The authors have ordered recent patents according to the primary applicant's name, with part 1 covering A through to I. Expert opinion: Inhibition of JAK-family kinases is an area of growing interest, catalysed by the maturity of data on marketed inhibitors ruxolitinib and tofacitinib in late stage clinical trials. Many applicants are pursuing traditional fast-follower strategies around these inhibitors, with a range of chemical strategies adopted. The challenge will be to show sufficient differentiation to the originator compounds, since dose limiting toxicities with such agents appear to be on target and mechanism-related and also considering that such agents may be available as generic compounds by the time follower agents reach market.

  15. Mitogen-Activated Protein Kinase-Interacting Kinase Regulates mTOR/AKT Signaling and Controls the Serine/Arginine-Rich Protein Kinase-Responsive Type 1 Internal Ribosome Entry Site-Mediated Translation and Viral Oncolysis

    PubMed Central

    Brown, Michael C.; Dobrikov, Mikhail I.

    2014-01-01

    ABSTRACT Translation machinery is a major recipient of the principal mitogenic signaling networks involving Raf-ERK1/2 and phosphoinositol 3-kinase (PI3K)-mechanistic target of rapamycin (mTOR). Picornavirus internal ribosomal entry site (IRES)-mediated translation and cytopathogenic effects are susceptible to the status of such signaling cascades in host cells. We determined that tumor-specific cytotoxicity of the poliovirus/rhinovirus chimera PVSRIPO is facilitated by Raf-ERK1/2 signals to the mitogen-activated protein kinase (MAPK)-interacting kinase (MNK) and its effects on the partitioning/activity of the Ser/Arg (SR)-rich protein kinase (SRPK) (M. C. Brown, J. D. Bryant, E. Y. Dobrikova, M. Shveygert, S. S. Bradrick, V. Chandramohan, D. D. Bigner, and M, Gromeier, J. Virol. 22:13135–13148, 2014, doi:http://dx.doi.org/10.1128/JVI.01883-14). Here, we show that MNK regulates SRPK via mTOR and AKT. Our investigations revealed a MNK-controlled mechanism acting on mTORC2-AKT. The resulting suppression of AKT signaling attenuates SRPK activity to enhance picornavirus type 1 IRES translation and favor PVSRIPO tumor cell toxicity and killing. IMPORTANCE Oncolytic immunotherapy with PVSRIPO, the type 1 live-attenuated poliovirus (PV) (Sabin) vaccine containing a human rhinovirus type 2 (HRV2) IRES, is demonstrating early promise in clinical trials with intratumoral infusion in recurrent glioblastoma (GBM). Our investigations demonstrate that the core mechanistic principle of PVSRIPO, tumor-selective translation and cytotoxicity, relies on constitutive ERK1/2-MNK signals that counteract the deleterious effects of runaway AKT-SRPK activity in malignancy. PMID:25187540

  16. High energy, low frequency, ultrasonic transducer

    DOEpatents

    Brown, Albert E.

    2000-01-01

    A wide bandwidth, ultrasonic transducer to generate nondispersive, extensional, pulsed acoustic pressure waves into concrete reinforced rods and tendons. The wave propagation distance is limited to double the length of the rod. The transducer acoustic impedance is matched to the rod impedance for maximum transfer of acoustic energy. The efficiency of the transducer is approximately 60 percent, depending upon the type of active elements used in the transducer. The transducer input energy is, for example, approximately 1 mJ. Ultrasonic reflections will occur at points along the rod where there are changes of one percent of a wavelength in the rod diameter. A reduction in the rod diameter will reflect a phase reversed echo, as compared with the reflection from an incremental increase in diameter. Echo signal processing of the stored waveform permits a reconstruction of those echoes into an image of the rod. The ultrasonic transducer has use in the acoustic inspection of long (40+foot) architectural reinforcements and structural supporting members, such as in bridges and dams.

  17. Tofacitinib, an Oral Janus Kinase Inhibitor: Pooled Efficacy and Safety Analyses in an Australian Rheumatoid Arthritis Population.

    PubMed

    Hall, Stephen; Nash, Peter; Rischmueller, Maureen; Bossingham, David; Bird, Paul; Cook, Nicola; Witcombe, David; Soma, Koshika; Kwok, Kenneth; Thirunavukkarasu, Krishan

    2018-06-11

    In Australia, there is an unmet need for improved treatments for rheumatoid arthritis (RA). Tofacitinib is an oral Janus kinase inhibitor for the treatment of RA. To provide an overview of key study outcomes for tofacitinib in Australian patients, we analyzed the efficacy and safety of tofacitinib in the Australian subpopulation of global RA phase III and long-term extension (LTE) studies. Data were pooled from the Australian subpopulation of four phase III studies and one LTE study (database not locked at cut-off date: January 2016). Patients in the phase III studies received tofacitinib 5 or 10 mg twice daily (BID), placebo (advancing to tofacitinib at months 3 or 6), or adalimumab, with background methotrexate or conventional synthetic disease-modifying antirheumatic drugs. Patients in the LTE study received tofacitinib 5 or 10 mg BID. Efficacy endpoints were American College of Rheumatology (ACR) 20/50/70 response rates, and change from baseline in the Disease Activity Score in 28 joints, erythrocyte sedimentation rate [DAS28-4(ESR)] and Health Assessment Questionnaire-Disability Index (HAQ-DI) scores. Safety endpoints included incidence of adverse events (AEs), serious AEs, and discontinuations due to AEs. AEs of special interest and laboratory parameters were analyzed in the LTE study. Across phase III studies (N = 100), ACR response rates and improvements in DAS28-4(ESR) and HAQ-DI scores were numerically greater with tofacitinib vs. placebo at month 3, and increased until month 12. The results were sustained in the LTE study (N = 99) after 60 months' observation. In general, the efficacy and safety profiles of tofacitinib were similar to those of the global RA population. In Australian patients with RA, tofacitinib therapy demonstrated sustained efficacy and consistent safety over ≥ 60 months' treatment. Pfizer Inc. TRIAL REGISTRATION NUMBERS (ALL CLINICALTRIALS.GOV): NCT00960440; NCT00847613; NCT00856544; NCT00853385; NCT00413699.

  18. JAK2/STAT5 inhibition by nilotinib with ruxolitinib contributes to the elimination of CML CD34+ cells in vitro and in vivo

    PubMed Central

    Gallipoli, Paolo; Cook, Amy; Rhodes, Susan; Hopcroft, Lisa; Wheadon, Helen; Whetton, Anthony D.; Jørgensen, Heather G.; Bhatia, Ravi

    2014-01-01

    Chronic myeloid leukemia (CML) stem cell survival is not dependent on BCR-ABL protein kinase and treatment with ABL tyrosine kinase inhibitors cures only a minority of CML patients, thus highlighting the need for novel therapeutic targets. The Janus kinase (JAK)2/signal transducer and activator of transcription (STAT)5 pathway has recently been explored for providing putative survival signals to CML stem/progenitor cells (SPCs) with contradictory results. We investigated the role of this pathway using the JAK2 inhibitor, ruxolitinib (RUX). We demonstrated that the combination of RUX, at clinically achievable concentrations, with the specific and potent tyrosine kinase inhibitor nilotinib, reduced the activity of the JAK2/STAT5 pathway in vitro relative to either single agent alone. These effects correlated with increased apoptosis of CML SPCs in vitro and a reduction in primitive quiescent CML stem cells, including NOD.Cg-Prkdcscid IL2rgtm1Wjl /SzJ mice repopulating cells, induced by combination treatment. A degree of toxicity toward normal SPCs was observed with the combination treatment, although this related to mature B-cell engraftment in NOD.Cg-Prkdcscid IL2rgtm1Wjl /SzJ mice with minimal effects on primitive CD34+ cells. These results support the JAK2/STAT5 pathway as a relevant therapeutic target in CML SPCs and endorse the current use of nilotinib in combination with RUX in clinical trials to eradicate persistent disease in CML patients. PMID:24957147

  19. Role of Gab1 in Heart, Placenta, and Skin Development and Growth Factor- and Cytokine-Induced Extracellular Signal-Regulated Kinase Mitogen-Activated Protein Kinase Activation

    PubMed Central

    Itoh, Motoyuki; Yoshida, Yuichi; Nishida, Keigo; Narimatsu, Masahiro; Hibi, Masahiko; Hirano, Toshio

    2000-01-01

    Gab1 is a member of the Gab/DOS (Daughter of Sevenless) family of adapter molecules, which contain a pleckstrin homology (PH) domain and potential binding sites for SH2 and SH3 domains. Gab1 is tyrosine phosphorylated upon stimulation of various cytokines, growth factors, and antigen receptors in cell lines and interacts with signaling molecules, such as SHP-2 and phosphatidylinositol 3-kinase, although its biological roles have not yet been established. To reveal the functions of Gab1 in vivo, we generated mice lacking Gab1 by gene targeting. Gab1-deficient embryos died in utero and displayed developmental defects in the heart, placenta, and skin, which were similar to phenotypes observed in mice lacking signals of the hepatocyte growth factor/scatter factor, platelet-derived growth factor, and epidermal growth factor pathways. Consistent with these observations, extracellular signal-regulated kinase mitogen-activated protein (ERK MAP) kinases were activated at much lower levels in cells from Gab1-deficient embryos in response to these growth factors or to stimulation of the cytokine receptor gp130. These results indicate that Gab1 is a common player in a broad range of growth factor and cytokine signaling pathways linking ERK MAP kinase activation. PMID:10779359

  20. Protein Kinase C Enzymes in the Hematopoietic and Immune Systems.

    PubMed

    Altman, Amnon; Kong, Kok-Fai

    2016-05-20

    The protein kinase C (PKC) family, discovered in the late 1970s, is composed of at least 10 serine/threonine kinases, divided into three groups based on their molecular architecture and cofactor requirements. PKC enzymes have been conserved throughout evolution and are expressed in virtually all cell types; they represent critical signal transducers regulating cell activation, differentiation, proliferation, death, and effector functions. PKC family members play important roles in a diverse array of hematopoietic and immune responses. This review covers the discovery and history of this enzyme family, discusses the roles of PKC enzymes in the development and effector functions of major hematopoietic and immune cell types, and points out gaps in our knowledge, which should ignite interest and further exploration, ultimately leading to better understanding of this enzyme family and, above all, its role in the many facets of the immune system.

  1. Cardiotrophin-1 Induces Matrix Metalloproteinase-1 in Human Aortic Endothelial Cells

    PubMed Central

    Tokito, Akinori; Jougasaki, Michihisa; Ichiki, Tomoko; Hamasaki, Shuichi

    2013-01-01

    Rupture of an atherosclerotic plaque is a key event in the development of cardiovascular disorders, in which matrix metalloproteinase-1 (MMP-1) plays a crucial role by degradation of extracellular matrix resulting in plaque instability. Cardiotrophin-1 (CT-1), a member of interleukin-6-type proinflammatory cytokines, has potent cardiovascular actions and is highly expressed in vascular endothelium, however its role in atherosclerosis has not been fully elucidated to date. The present study was designed to investigate whether CT-1 induces MMP-1 in human aortic endothelial cells (HAECs). Ribonuclease protection assay demonstrated that MMP-1 gene level in HAECs was enhanced by the treatment of CT-1 in a dose- and time-dependent manner. Immunocytochemical staining, Western immunoblot analysis and enzyme-linked immunosorbent assay revealed that CT-1 augmented MMP-1 protein synthesis and secretion. MMP-1 activity assay revealed that MMP-1 present in the supernatant of HAECs was exclusively precursor form. Casein zymography disclosed proteolytic activity in the supernatant of HAECs, which was enhanced by CT-1 treatment. Furthermore, pharmacological inhibitor study indicated the important roles of extracellular signal-regulated kinase (ERK) 1/2, p38 mitogen-activated protein (MAP) kinase, c-Jun N-terminal kinase (JNK) and Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathways in mediating CT-1-induced MMP-1 gene and protein expression. These data reveal for the first time that CT-1 induces the proteolytic potential in HAECs by upregulating MMP-1 expression through ERK1/2, p38 MAP kinase, JNK and JAK/STAT pathways, and suggest that CT-1 may play an important role in the pathophysiology of atherosclerosis and plaque instability. PMID:23935888

  2. A bioanalytical microsystem for protein and DNA sensing based on a monolithic silicon optoelectronic transducer

    NASA Astrophysics Data System (ADS)

    Misiakos, K.; Petrou, P. S.; Kakabakos, S. E.; Ruf, H. H.; Ehrentreich-Förster, E.; Bier, F. F.

    2005-01-01

    A bioanalytical microsystem that is based on a monolithic silicon optical transducer and a microfluidic module and it is appropriate for real-time sensing of either DNA or protein analytes is presented. The optical transducer monolithically integrates silicon avalanche diodes as light sources, silicon nitride optical fibers and detectors and efficiently intercouples these optical elements through a self-alignment technique. After hydrophilization and silanization of the transducer surface, the biomolecular probes are immobilized through physical adsorption. Detection is performed through reaction of the immobilized biomolecules with gold nanoparticle labeled counterpart molecules. The binding of these molecules within the evanescent field at the surface of the optical fiber cause attenuated total reflection of the waveguided modes and reduction of the detector photocurrent. Using the developed microsystem, determination of single nucleotide polymorphism (SNP) in the gene of the human phenol sulfotransferase SULT1A1 was achieved. Full-matching hybrid resulted in 4-5 times higher signals compared to the mismatched hybrid after hybridization and dissociation processes. The protein sensing abilities of the developed microsystem were also investigated through a non-competitive assay for the determination of the MB isoform of creatine kinase enzyme (CK-MB) that is a widely used cardiac marker.

  3. Evolution and Design Governing Signal Precision and Amplification in a Bacterial Chemosensory Pathway

    PubMed Central

    Espinosa, Leon; Baronian, Grégory; Molle, Virginie; Mauriello, Emilia M. F.; Brochier-Armanet, Céline; Mignot, Tâm

    2015-01-01

    Understanding the principles underlying the plasticity of signal transduction networks is fundamental to decipher the functioning of living cells. In Myxococcus xanthus, a particular chemosensory system (Frz) coordinates the activity of two separate motility systems (the A- and S-motility systems), promoting multicellular development. This unusual structure asks how signal is transduced in a branched signal transduction pathway. Using combined evolution-guided and single cell approaches, we successfully uncoupled the regulations and showed that the A-motility regulation system branched-off an existing signaling system that initially only controlled S-motility. Pathway branching emerged in part following a gene duplication event and changes in the circuit structure increasing the signaling efficiency. In the evolved pathway, the Frz histidine kinase generates a steep biphasic response to increasing external stimulations, which is essential for signal partitioning to the motility systems. We further show that this behavior results from the action of two accessory response regulator proteins that act independently to filter and amplify signals from the upstream kinase. Thus, signal amplification loops may underlie the emergence of new connectivity in signal transduction pathways. PMID:26291327

  4. The JAK inhibitor tofacitinib suppresses synovial JAK1-STAT signalling in rheumatoid arthritis

    PubMed Central

    Boyle, D L; Soma, K; Hodge, J; Kavanaugh, A; Mandel, D; Mease, P; Shurmur, R; Singhal, A K; Wei, N; Rosengren, S; Kaplan, I; Krishnaswami, S; Luo, Z; Bradley, J; Firestein, G S

    2015-01-01

    Objective Tofacitinib is an oral Janus kinase (JAK) inhibitor for the treatment of rheumatoid arthritis (RA). The pathways affected by tofacitinib and the effects on gene expression in situ are unknown. Therefore, tofacitinib effects on synovial pathobiology were investigated. Methods A randomised, double-blind, phase II serial synovial biopsy study (A3921073; NCT00976599) in patients with RA with an inadequate methotrexate response. Patients on background methotrexate received tofacitinib 10 mg twice daily or placebo for 28 days. Synovial biopsies were performed on Days -7 and 28 and analysed by immunoassay or quantitative PCR. Clinical response was determined by disease activity score and European League Against Rheumatism (EULAR) response on Day 28 in A3921073, and at Month 3 in a long-term extension study (A3921024; NCT00413699). Results Tofacitinib exposure led to EULAR moderate to good responses (11/14 patients), while placebo was ineffective (1/14 patients) on Day 28. Tofacitinib treatment significantly reduced synovial mRNA expression of matrix metalloproteinase (MMP)-1 and MMP-3 (p<0.05) and chemokines CCL2, CXCL10 and CXCL13 (p<0.05). No overall changes were observed in synovial inflammation score or the presence of T cells, B cells or macrophages. Changes in synovial phosphorylation of signal transducer and activator of transcription 1 (STAT1) and STAT3 strongly correlated with 4-month clinical responses (p<0.002). Tofacitinib significantly decreased plasma CXCL10 (p<0.005) at Day 28 compared with placebo. Conclusions Tofacitinib reduces metalloproteinase and interferon-regulated gene expression in rheumatoid synovium, and clinical improvement correlates with reductions in STAT1 and STAT3 phosphorylation. JAK1-mediated interferon and interleukin-6 signalling likely play a key role in the synovial response. Trial registration number NCT00976599. PMID:25398374

  5. Chronic active Epstein-Barr virus infection as the initial symptom in a Janus kinase 3 deficiency child: Case report and literature review.

    PubMed

    Zhong, Linqing; Wang, Wei; Ma, Mingsheng; Gou, Lijuan; Tang, Xiaoyan; Song, Hongmei

    2017-10-01

    With the progress of sequencing technology, an increasing number of atypical primary immunodeficiency (PID) patients have been discovered, including Janus kinase 3 (JAK3) gene deficiency. We report a patient who presented with chronic active Epstein-Barr virus (CAEBV) infection but responded poorly to treatment with ganciclovir. Next-generation sequencing (NGS) was performed, including all known PID genes, after which Sanger sequencing was performed to verify the results. Genetic analysis revealed that our patient had 2 novel compound heterozygous mutations of JAK3, a gene previously reported to cause a rare form of autosomal recessive severe combined immunodeficiency with recurrent infections. The p.H27Q mutation came from his father, while p. R222H from his mother. Thus, his diagnosis was corrected for JAK3-deficiency PID and CAEBV. Maintenance treatment of subcutaneous injection of recombinant human interferon α-2a was given to our patient with 2 MU, 3 times a week. Interferon alpha was applied and the EBV infection was gradually controlled and his symptoms ameliorated remarkably. Our patient is in good health now and did not have relapses. The diagnoses of PID should be taken into consideration when CAEBV patients respond poorly to conventional treatments. Good results of our patient indicate that interferon α-2a may be an alternative treatment for those who are unwilling to accept hematopoietic stem cell transplantation (HSCT) like our patient. Literature review identified 59 additional cases of JAK3 deficiency with various infections.

  6. Dual-Frequency Piezoelectric Transducers for Contrast Enhanced Ultrasound Imaging

    PubMed Central

    Martin, K. Heath; Lindsey, Brooks D.; Ma, Jianguo; Lee, Mike; Li, Sibo; Foster, F. Stuart; Jiang, Xiaoning; Dayton, Paul A.

    2014-01-01

    For many years, ultrasound has provided clinicians with an affordable and effective imaging tool for applications ranging from cardiology to obstetrics. Development of microbubble contrast agents over the past several decades has enabled ultrasound to distinguish between blood flow and surrounding tissue. Current clinical practices using microbubble contrast agents rely heavily on user training to evaluate degree of localized perfusion. Advances in separating the signals produced from contrast agents versus surrounding tissue backscatter provide unique opportunities for specialized sensors designed to image microbubbles with higher signal to noise and resolution than previously possible. In this review article, we describe the background principles and recent developments of ultrasound transducer technology for receiving signals produced by contrast agents while rejecting signals arising from soft tissue. This approach relies on transmitting at a low-frequency and receiving microbubble harmonic signals at frequencies many times higher than the transmitted frequency. Design and fabrication of dual-frequency transducers and the extension of recent developments in transducer technology for dual-frequency harmonic imaging are discussed. PMID:25375755

  7. Dual-frequency piezoelectric transducers for contrast enhanced ultrasound imaging.

    PubMed

    Martin, K Heath; Lindsey, Brooks D; Ma, Jianguo; Lee, Mike; Li, Sibo; Foster, F Stuart; Jiang, Xiaoning; Dayton, Paul A

    2014-11-04

    For many years, ultrasound has provided clinicians with an affordable and effective imaging tool for applications ranging from cardiology to obstetrics. Development of microbubble contrast agents over the past several decades has enabled ultrasound to distinguish between blood flow and surrounding tissue. Current clinical practices using microbubble contrast agents rely heavily on user training to evaluate degree of localized perfusion. Advances in separating the signals produced from contrast agents versus surrounding tissue backscatter provide unique opportunities for specialized sensors designed to image microbubbles with higher signal to noise and resolution than previously possible. In this review article, we describe the background principles and recent developments of ultrasound transducer technology for receiving signals produced by contrast agents while rejecting signals arising from soft tissue. This approach relies on transmitting at a low-frequency and receiving microbubble harmonic signals at frequencies many times higher than the transmitted frequency. Design and fabrication of dual-frequency transducers and the extension of recent developments in transducer technology for dual-frequency harmonic imaging are discussed.

  8. Essential role of protein kinase C zeta in transducing a motility signal induced by superoxide and a chemotactic peptide, fMLP.

    PubMed

    Kuribayashi, Kageaki; Nakamura, Kiminori; Tanaka, Maki; Sato, Tsutomu; Kato, Junji; Sasaki, Katsunori; Takimoto, Rishu; Kogawa, Katsuhisa; Terui, Takeshi; Takayama, Tetsuji; Onuma, Takayuki; Matsunaga, Takuya; Niitsu, Yoshiro

    2007-03-26

    Under various pathological conditions, including infection, malignancy, and autoimmune diseases, tissues are incessantly exposed to reactive oxygen species produced by infiltrating inflammatory cells. We show augmentation of motility associated with morphological changes of human squamous carcinoma SASH1 cells, human peripheral monocytes (hPMs), and murine macrophage-like cell line J774.1 by superoxide stimulation. We also disclose that motility of hPMs and J774.1 induced by a chemotactic peptide (N-formyl-methionyl-leucyl-phenylalanine [fMLP]) was inhibited by superoxide dismutase or N-acetylcystein, indicating stimulation of motility by superoxide generated by fMLP stimulation. In these cells, protein kinase C (PKC) zeta was activated to phosphorylate RhoGDI-1, which liberated RhoGTPases, leading to their activation. These events were inhibited by dominant-negative PKCzeta in SASH1 cells, myristoylated PKCzeta peptides in hPMs and J774.1, or a specific inhibitor of RhoGTPase in SASH1, hPMs, and J774.1. These results suggest a new approach for manipulation of inflammation as well as tumor cell invasion by targeting this novel signaling pathway.

  9. Absolute calibration technique for broadband ultrasonic transducers

    NASA Technical Reports Server (NTRS)

    Yost, William T. (Inventor); Cantrell, John H. (Inventor)

    1994-01-01

    Calibrating an ultrasonic transducer can be performed with a reduced number of calculations and testing. A wide-band pulser is connected to an ultrasonic transducer under test to generate ultrasonic waves in a liquid. A single frequency is transmitted to the electrostatic acoustic transducer (ESAT) and the voltage change produced is monitored. Then a broadband ultrasonic pulse is generated by the ultrasonic transducer and received by the ESAT. The output of the ESAT is amplified and input to a digitized oscilloscope for fast Fourier transform. The resulting plot is normalized with the monitored signal from the single frequency pulse. The plot is then corrected for characteristics of the membrane and diffraction effects. The transfer function of the final plot is determined. The transfer function gives the final sensitivity of the ultrasonic transducer as a function of frequency. The advantage of the system is the speed of calibrating the transducer by a reduced number of measurements and removal of the membrane and diffraction effects.

  10. Focusing of ferroelectret air-coupled ultrasound transducers

    NASA Astrophysics Data System (ADS)

    Gaal, Mate; Bartusch, Jürgen; Dohse, Elmar; Schadow, Florian; Köppe, Enrico

    2016-02-01

    Air-coupled ultrasound has been applied increasingly as a non-destructive testing method for lightweight construction in recent years. It is particularly appropriate for composite materials being used in automotive and aviation industry. Air-coupled ultrasound transducers mostly consist of piezoelectric materials and matching layers. However, their fabrication is challenging and their signal-to-noise ratio often not sufficient for many testing requirements. To enhance the efficiency, air-coupled ultrasound transducers made of cellular polypropylene have been developed. Because of its small density and sound velocity, this piezoelectric ferroelectret matches the small acoustic impedance of air much better than matching layers applied in conventional transducers. In our contribution, we present two different methods of spherical focusing of ferroelectret transducers for the further enhancement of their performance in NDT applications. Measurements on carbon-fiber-reinforced polymer (CFRP) samples and on metal adhesive joints performed with commercially available focused air-coupled ultrasound transducers are compared to measurements executed with self-developed focused ferroelectret transducers.

  11. Motion of a Janus particle very near a wall

    NASA Astrophysics Data System (ADS)

    Rashidi, Aidin; Wirth, Christopher L.

    2017-12-01

    This article describes the simulated Brownian motion of a sphere comprising hemispheres of unequal zeta potential (i.e., "Janus" particle) very near a wall. The simulation tool was developed and used to assist in the methodology development for applying Total Internal Reflection Microscopy (TIRM) to anisotropic particles. Simulations of the trajectory of a Janus sphere with cap density matching that of the base particle very near a boundary were used to construct 3D potential energy landscapes that were subsequently used to infer particle and solution properties, as would be done in a TIRM measurement. Results showed that the potential energy landscape of a Janus sphere has a transition region at the location of the boundary between the two Janus halves, which depended on the relative zeta potential magnitude. The potential energy landscape was fit to accurately obtain the zeta potential of each hemisphere, particle size, minimum potential energy position and electrolyte concentration, or Debye length. We also determined the appropriate orientation bin size and regimes over which the potential energy landscape should be fit to obtain system properties. Our simulations showed that an experiment may require more than 106 observations to obtain a suitable potential energy landscape as a consequence of the multivariable nature of observations for an anisotropic particle. These results illustrate important considerations for conducting TIRM for anisotropic particles.

  12. Receptor kinase complex transmits RALF peptide signal to inhibit root growth in Arabidopsis.

    PubMed

    Du, Changqing; Li, Xiushan; Chen, Jia; Chen, Weijun; Li, Bin; Li, Chiyu; Wang, Long; Li, Jianglin; Zhao, Xiaoying; Lin, Jianzhong; Liu, Xuanming; Luan, Sheng; Yu, Feng

    2016-12-20

    A number of hormones work together to control plant cell growth. Rapid Alkalinization Factor 1 (RALF1), a plant-derived small regulatory peptide, inhibits cell elongation through suppression of rhizosphere acidification in plants. Although a receptor-like kinase, FERONIA (FER), has been shown to act as a receptor for RALF1, the signaling mechanism remains unknown. In this study, we identified a receptor-like cytoplasmic kinase (RPM1-induced protein kinase, RIPK), a plasma membrane-associated member of the RLCK-VII subfamily, that is recruited to the receptor complex through interacting with FER in response to RALF1. RALF1 triggers the phosphorylation of both FER and RIPK in a mutually dependent manner. Genetic analysis of the fer-4 and ripk mutants reveals RIPK, as well as FER, to be required for RALF1 response in roots. The RALF1-FER-RIPK interactions may thus represent a mechanism for peptide signaling in plants.

  13. Multiple signals modulate the activity of the complex sensor kinase TodS

    PubMed Central

    Silva-Jiménez, Hortencia; Ortega, Álvaro; García-Fontana, Cristina; Ramos, Juan Luis; Krell, Tino

    2015-01-01

    The reason for the existence of complex sensor kinases is little understood but thought to lie in the capacity to respond to multiple signals. The complex, seven-domain sensor kinase TodS controls in concert with the TodT response regulator the expression of the toluene dioxygenase pathway in Pseudomonas putida F1 and DOT-T1E. We have previously shown that some aromatic hydrocarbons stimulate TodS activity whereas others behave as antagonists. We show here that TodS responds in addition to the oxidative agent menadione. Menadione but no other oxidative agent tested inhibited TodS activity in vitro and reduced PtodX expression in vivo. The menadione signal is incorporated by a cysteine-dependent mechanism. The mutation of the sole conserved cysteine of TodS (C320) rendered the protein insensitive to menadione. We evaluated the mutual opposing effects of toluene and menadione on TodS autophosphorylation. In the presence of toluene, menadione reduced TodS activity whereas toluene did not stimulate activity in the presence of menadione. It was shown by others that menadione increases expression of glucose metabolism genes. The opposing effects of menadione on glucose and toluene metabolism may be partially responsible for the interwoven regulation of both catabolic pathways. This work provides mechanistic detail on how complex sensor kinases integrate different types of signal molecules. PMID:24986263

  14. Kinase cascades and ligand-directed signaling at the kappa opioid receptor.

    PubMed

    Bruchas, Michael R; Chavkin, Charles

    2010-06-01

    The dynorphin/kappa opioid receptor (KOR) system has been implicated as a critical component of the stress response. Stress-induced activation of dynorphin-KOR is well known to produce analgesia, and more recently, it has been implicated as a mediator of stress-induced responses including anxiety, depression, and reinstatement of drug seeking. Drugs selectively targeting specific KOR signaling pathways may prove potentially useful as therapeutic treatments for mood and addiction disorders. KOR is a member of the seven transmembrane spanning (7TM) G-protein coupled receptor (GPCR) superfamily. KOR activation of pertussis toxin-sensitive G proteins leads to Galphai/o inhibition of adenylyl cyclase production of cAMP and releases Gbetagamma, which modulates the conductances of Ca(+2) and K(+) channels. In addition, KOR agonists activate kinase cascades including G-protein coupled Receptor Kinases (GRK) and members of the mitogen-activated protein kinase (MAPK) family: ERK1/2, p38 and JNK. Recent pharmacological data suggests that GPCRs exist as dynamic, multi-conformational protein complexes that can be directed by specific ligands towards distinct signaling pathways. Ligand-induced conformations of KOR that evoke beta-arrestin-dependent p38 MAPK activation result in aversion; whereas ligand-induced conformations that activate JNK without activating arrestin produce long-lasting inactivation of KOR signaling. In this review, we discuss the current status of KOR signal transduction research and the data that support two novel hypotheses: (1) KOR selective partial agonists that do not efficiently activate p38 MAPK may be useful analgesics without producing the dysphoric or hallucinogenic effects of selective, highly efficacious KOR agonists and (2) KOR antagonists that do not activate JNK may be effective short-acting drugs that may promote stress-resilience.

  15. C-Jun N-terminal kinase signalling pathway in response to cisplatin.

    PubMed

    Yan, Dong; An, GuangYu; Kuo, Macus Tien

    2016-11-01

    Cisplatin (cis diamminedichloroplatinum II, cDDP) is one of the most effective cancer chemotherapeutic agents and is used in the treatment of many types of human malignancies. However, inherent tumour resistance is a major barrier to effective cisplatin therapy. So far, the mechanism of cDDP resistance has not been well defined. In general, cisplatin is considered to be a cytotoxic drug, for damaging DNA and inhibiting DNA synthesis, resulting in apoptosis via the mitochondrial death pathway or plasma membrane disruption. cDDP-induced DNA damage triggers signalling pathways that will eventually decide between cell life and death. As a member of the mitogen-activated protein kinases family, c-Jun N-terminal kinase (JNK) is a signalling pathway in response to extracellular stimuli, especially drug treatment, to modify the activity of numerous proteins locating in the mitochondria or the nucleus. Recent studies suggest that JNK signalling pathway plays a major role in deciding the fate of the cell and inducing resistance to cDDP-induced apoptosis in human tumours. c-Jun N-terminal kinase regulates several important cellular functions including cell proliferation, differentiation, survival and apoptosis while activating and inhibiting substrates for phosphorylation transcription factors (c-Jun, ATF2: Activating transcription factor 2, p53 and so on), which subsequently induce pro-apoptosis and pro-survival factors expression. Therefore, it is suggested that JNK signal pathway is a double-edged sword in cDDP treatment, simultaneously being a significant pro-apoptosis factor but also being associated with increased resistance to cisplatin-based chemotherapy. This review focuses on current knowledge concerning the role of JNK in cell response to cDDP, as well as their role in cisplatin resistance. © 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  16. Dual-Use Transducer for Use with a Boundary-Stiffened Panel and Method of Using the Same

    NASA Technical Reports Server (NTRS)

    Schiller, Noah H. (Inventor); Cabell, Randolph H. (Inventor)

    2011-01-01

    A transducer for use with a boundary-stiffened panel has an inter-digitated electrode (IDE) and a piezoelectric wafer portion positioned therebetween. The IDE and/or the wafer portion are triangular, with one edge or side aligned with a boundary edge of the panel. The transducer generates and transmits an output force to the panel in response to an input voltage signal from a sensor, which can be another transducer as described above or an accelerometer. A controller can generate an output force signal in response to the input voltage signal to help cancel the input voltage signal. A method of using the transducer minimizes vibration in the panel by connecting multiple transducers around a perimeter thereof. Motion is measured at different portions of the panel, and a voltage signal determined from the motion is transmitted to the transducers to generate an output force at least partially cancelling or damping the motion.

  17. Direct Interaction of Jak1 and v-Abl Is Required for v-Abl-Induced Activation of STATs and Proliferation

    PubMed Central

    Danial, Nika N.; Losman, Julie A.; Lu, Tianhong; Yip, Natalie; Krishnan, Kartik; Krolewski, John; Goff, Stephen P.; Wang, Jean Y. J.; Rothman, Paul B.

    1998-01-01

    In Abelson murine leukemia virus (A-MuLV)-transformed cells, members of the Janus kinase (Jak) family of non-receptor tyrosine kinases and the signal transducers and activators of transcription (STAT) family of signaling proteins are constitutively activated. In these cells, the v-Abl oncoprotein and the Jak proteins physically associate. To define the molecular mechanism of constitutive Jak-STAT signaling in these cells, the functional significance of the v-Abl–Jak association was examined. Mapping the Jak1 interaction domain in v-Abl demonstrates that amino acids 858 to 1080 within the carboxyl-terminal region of v-Abl bind Jak1 through a direct interaction. A mutant of v-Abl lacking this region exhibits a significant defect in Jak1 binding in vivo, fails to activate Jak1 and STAT proteins, and does not support either the proliferation or the survival of BAF/3 cells in the absence of cytokine. Cells expressing this v-Abl mutant show extended latency and decreased frequency in generating tumors in nude mice. In addition, inducible expression of a kinase-inactive mutant of Jak1 protein inhibits the ability of v-Abl to activate STATs and to induce cytokine-independent proliferation, indicating that an active Jak1 is required for these v-Abl-induced signaling pathways in vivo. We propose that Jak1 is a mediator of v-Abl-induced STAT activation and v-Abl induced proliferation in BAF/3 cells, and may be important for efficient transformation of immature B cells by the v-abl oncogene. PMID:9774693

  18. Neogenin Regulates Skeletal Myofiber Size and Focal Adhesion Kinase and Extracellular Signal-regulated Kinase Activities In Vivo and In Vitro

    PubMed Central

    Bae, Gyu-Un; Yang, Youn-Joo; Jiang, Guoying; Hong, Mingi; Lee, Hye-Jin; Tessier-Lavigne, Marc

    2009-01-01

    A variety of signaling pathways participate in the development of skeletal muscle, but the extracellular cues that regulate such pathways in myofiber formation are not well understood. Neogenin is a receptor for ligands of the netrin and repulsive guidance molecule (RGM) families involved in axon guidance. We reported previously that neogenin promoted myotube formation by C2C12 myoblasts in vitro and that the related protein Cdo (also Cdon) was a potential neogenin coreceptor in myoblasts. We report here that mice homozygous for a gene-trap mutation in the Neo1 locus (encoding neogenin) develop myotomes normally but have small myofibers at embryonic day 18.5 and at 3 wk of age. Similarly, cultured myoblasts derived from such animals form smaller myotubes with fewer nuclei than myoblasts from control animals. These in vivo and in vitro defects are associated with low levels of the activated forms of focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK), both known to be involved in myotube formation, and inefficient expression of certain muscle-specific proteins. Recombinant netrin-2 activates FAK and ERK in cultured myoblasts in a neogenin- and Cdo-dependent manner, whereas recombinant RGMc displays lesser ability to activate these kinases. Together, netrin-neogenin signaling is an important extracellular cue in regulation of myogenic differentiation and myofiber size. PMID:19812254

  19. 21 CFR 870.2900 - Patient transducer and electrode cable (including connector).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Patient transducer and electrode cable (including... § 870.2900 Patient transducer and electrode cable (including connector). (a) Identification. A patient transducer and electrode cable (including connector) is an electrical conductor used to transmit signals from...

  20. 21 CFR 870.2900 - Patient transducer and electrode cable (including connector).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Patient transducer and electrode cable (including... § 870.2900 Patient transducer and electrode cable (including connector). (a) Identification. A patient transducer and electrode cable (including connector) is an electrical conductor used to transmit signals from...

  1. 21 CFR 870.2900 - Patient transducer and electrode cable (including connector).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Patient transducer and electrode cable (including... § 870.2900 Patient transducer and electrode cable (including connector). (a) Identification. A patient transducer and electrode cable (including connector) is an electrical conductor used to transmit signals from...

  2. Mitogen-activated protein kinase-interacting kinase regulates mTOR/AKT signaling and controls the serine/arginine-rich protein kinase-responsive type 1 internal ribosome entry site-mediated translation and viral oncolysis.

    PubMed

    Brown, Michael C; Dobrikov, Mikhail I; Gromeier, Matthias

    2014-11-01

    Translation machinery is a major recipient of the principal mitogenic signaling networks involving Raf-ERK1/2 and phosphoinositol 3-kinase (PI3K)-mechanistic target of rapamycin (mTOR). Picornavirus internal ribosomal entry site (IRES)-mediated translation and cytopathogenic effects are susceptible to the status of such signaling cascades in host cells. We determined that tumor-specific cytotoxicity of the poliovirus/rhinovirus chimera PVSRIPO is facilitated by Raf-ERK1/2 signals to the mitogen-activated protein kinase (MAPK)-interacting kinase (MNK) and its effects on the partitioning/activity of the Ser/Arg (SR)-rich protein kinase (SRPK) (M. C. Brown, J. D. Bryant, E. Y. Dobrikova, M. Shveygert, S. S. Bradrick, V. Chandramohan, D. D. Bigner, and M, Gromeier, J. Virol. 22:13135-13148, 2014, doi:http://dx.doi.org/10.1128/JVI.01883-14). Here, we show that MNK regulates SRPK via mTOR and AKT. Our investigations revealed a MNK-controlled mechanism acting on mTORC2-AKT. The resulting suppression of AKT signaling attenuates SRPK activity to enhance picornavirus type 1 IRES translation and favor PVSRIPO tumor cell toxicity and killing. Oncolytic immunotherapy with PVSRIPO, the type 1 live-attenuated poliovirus (PV) (Sabin) vaccine containing a human rhinovirus type 2 (HRV2) IRES, is demonstrating early promise in clinical trials with intratumoral infusion in recurrent glioblastoma (GBM). Our investigations demonstrate that the core mechanistic principle of PVSRIPO, tumor-selective translation and cytotoxicity, relies on constitutive ERK1/2-MNK signals that counteract the deleterious effects of runaway AKT-SRPK activity in malignancy. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  3. Design of compact piezoelectric transducers for shock wave applications

    NASA Astrophysics Data System (ADS)

    Dreyer, Thomas; Liebler, Marko; Riedlinger, Rainer E.; Ginter, Siegfried

    2003-10-01

    The application of focused intense sound pulses to treat several orthopedic diseases has gained in importance during the past years. Self-focusing piezoelectric transducers known from ESWL are not well suited for this purpose due to their size. Therefore compact transducers have to be designed. This implies an increase of the pressure pulse amplitude generated at the radiating surface. A stacked placement of two piezoelectric layers driven by two high-voltage pulses with an adjustable delay accomplishes this. Several designs are presented here representing transducers of different sizes. In principle piezoelectric transducers have the ability to vary the pressure pulse shape to a wider extent than other shock wave sources. Based on FEM simulations of the transducer the influence of some driving parameters, like a variation of the interpulse delay or shape of the driving voltage, on the resulting focal pressure signal is demonstrated. The results show the feasibility to control some parameters of the signal, for example the peak negative pressure amplitude. This possibility could provide new aspects in basic research as well as in clinical applications.

  4. Molecular pathways of platelet factor 4/CXCL4 signaling.

    PubMed

    Kasper, Brigitte; Petersen, Frank

    2011-01-01

    The platelet-derived chemokine CXCL4 takes a specific and unique position within the family of chemotactic cytokines. Today, much attention is directed to CXCL4's capacity to inhibit angiogenesis and to promote innate immune responses, which makes this chemokine an interesting tool and target for potential intervention in tumor growth and inflammation. However, such attempts demand a comprehensive knowledge on the molecular mechanisms and pathways underlying the corresponding cellular functions. At least two structurally different receptors, CXCR3-B and a chondroitin sulfate proteoglycan, are capable of binding CXCL4 and to induce a specific intracellular signaling machinery. While signaling mediated by CXCR3-B involves Gs proteins, elevated cAMP levels, and p38 MAP kinase, signaling via proteoglycans appears to be more complicated and varies strongly between the cell types analyzed. In CXCL4-activated neutrophils and monocytes, tyrosine kinases of the Src family and Syk as well as monomeric GTPases and members of the MAP kinase family have been identified as essential intracellular signals. Most intriguingly, signaling does not proceed in a linear sequence of events but in a repeated activation of certain transducing elements like Rac2 or sphingosine kinase 1. Depending on the downstream targets, such biphasic kinetics either leads to a redundant and prolonged activation of a single pathway or to a timely separated initiation of disparate signals and functions. Results of the studies reviewed here help to understand the molecular basis of CXCL4's functional diversity and provide insights into integrated signaling processes in general. Copyright © 2011 Elsevier GmbH. All rights reserved.

  5. AUTOMATIC CALIBRATING SYSTEM FOR PRESSURE TRANSDUCERS

    DOEpatents

    Amonette, E.L.; Rodgers, G.W.

    1958-01-01

    An automatic system for calibrating a number of pressure transducers is described. The disclosed embodiment of the invention uses a mercurial manometer to measure the air pressure applied to the transducer. A servo system follows the top of the mercury column as the pressure is changed and operates an analog- to-digital converter This converter furnishes electrical pulses, each representing an increment of pressure change, to a reversible counterThe transducer furnishes a signal at each calibration point, causing an electric typewriter and a card-punch machine to record the pressure at the instant as indicated by the counter. Another counter keeps track of the calibration points so that a number identifying each point is recorded with the corresponding pressure. A special relay control system controls the pressure trend and programs the sequential calibration of several transducers.

  6. Characterization of Transducers and Resonators under High Drive Levels

    NASA Technical Reports Server (NTRS)

    Sherrit, Stewart; Bao, X.; Sigel, D. A.; Gradziel, M. J.; Askins, S. A.; Dolgin, B. P.; Bar-Cohen, Y.

    2001-01-01

    In many applications, piezoelectric transducers are driven at AC voltage levels well beyond the level for which the material was nominally characterized. In this paper we describe an experimental setup that allows for the determination of the main transducer or resonator properties under large AC drive. A sinusoidal voltage from a waveform generator is amplified and applied across the transducer/resonator in series with a known high power resistor. The amplitude of applied voltage and the amplitude and the relative phase of the current through the resistor are monitored on a digital scope. The frequency of the applied signal is swept through resonance and the voltage/current signals are recorded. After corrections for the series resistance and parasitic elements the technique allows for the determination of the complex impedance spectra of the sample as a function of frequency. In addition, access to the current signal allows for the direct investigation of non-linear effects through the application of Fourier transform techniques on the current signal. Our results indicate that care is required when interpreting impedance data at high drive level due to the frequency dependence of the dissipated power. Although the transducer/resonator at a single frequency and after many cycles may reach thermal equilibrium, the spectra as a whole cannot be considered an isothermal measurement due to the temperature change with frequency. Methods to correct for this effect will be discussed. Results determined from resonators of both soft and hard PZT and a ultrasonic horn transducer are presented.

  7. Hybrid Nanowire Ion-to-Electron Transducers for Integrated Bioelectronic Circuitry.

    PubMed

    Carrad, D J; Mostert, A B; Ullah, A R; Burke, A M; Joyce, H J; Tan, H H; Jagadish, C; Krogstrup, P; Nygård, J; Meredith, P; Micolich, A P

    2017-02-08

    A key task in the emerging field of bioelectronics is the transduction between ionic/protonic and electronic signals at high fidelity. This is a considerable challenge since the two carrier types exhibit intrinsically different physics and are best supported by very different materials types-electronic signals in inorganic semiconductors and ionic/protonic signals in organic or bio-organic polymers, gels, or electrolytes. Here we demonstrate a new class of organic-inorganic transducing interface featuring semiconducting nanowires electrostatically gated using a solid proton-transporting hygroscopic polymer. This model platform allows us to study the basic transducing mechanisms as well as deliver high fidelity signal conversion by tapping into and drawing together the best candidates from traditionally disparate realms of electronic materials research. By combining complementary n- and p-type transducers we demonstrate functional logic with significant potential for scaling toward high-density integrated bioelectronic circuitry.

  8. PI3 kinase inhibition improves vascular malformations in mouse models of hereditary haemorrhagic telangiectasia.

    PubMed

    Ola, Roxana; Dubrac, Alexandre; Han, Jinah; Zhang, Feng; Fang, Jennifer S; Larrivée, Bruno; Lee, Monica; Urarte, Ana A; Kraehling, Jan R; Genet, Gael; Hirschi, Karen K; Sessa, William C; Canals, Francesc V; Graupera, Mariona; Yan, Minhong; Young, Lawrence H; Oh, Paul S; Eichmann, Anne

    2016-11-29

    Activin receptor-like kinase 1 (ALK1) is an endothelial serine-threonine kinase receptor for bone morphogenetic proteins (BMPs) 9 and 10. Inactivating mutations in the ALK1 gene cause hereditary haemorrhagic telangiectasia type 2 (HHT2), a disabling disease characterized by excessive angiogenesis with arteriovenous malformations (AVMs). Here we show that inducible, endothelial-specific homozygous Alk1 inactivation and BMP9/10 ligand blockade both lead to AVM formation in postnatal retinal vessels and internal organs including the gastrointestinal (GI) tract in mice. VEGF and PI3K/AKT signalling are increased on Alk1 deletion and BMP9/10 ligand blockade. Genetic deletion of the signal-transducing Vegfr2 receptor prevents excessive angiogenesis but does not fully revert AVM formation. In contrast, pharmacological PI3K inhibition efficiently prevents AVM formation and reverts established AVMs. Thus, Alk1 deletion leads to increased endothelial PI3K pathway activation that may be a novel target for the treatment of vascular lesions in HHT2.

  9. MEMS ultrasonic transducer for monitoring of steel structures

    NASA Astrophysics Data System (ADS)

    Jain, Akash; Greve, David W.; Oppenheim, Irving J.

    2002-06-01

    Ultrasonic methods can be used to monitor crack propagation, weld failure, or section loss at critical locations in steel structures. However, ultrasonic inspection requires a skilled technician, and most commonly the signal obtained at any inspection is not preserved for later use. A preferred technology would use a MEMS device permanently installed at a critical location, polled remotely, and capable of on-chip signal processing using a signal history. We review questions related to wave geometry, signal levels, flaw localization, and electromechanical design issues for microscale transducers, and then describe the design, characterization, and initial testing of a MEMS transducer to function as a detector array. The device is approximately 1-cm square and was fabricated by the MUMPS process. The chip has 23 sensor elements to function in a phased array geometry, each element containing 180 hexagonal polysilicon diaphragms with a typical leg length of 49 microns and an unloaded natural frequency near 3.5 MHz. We first report characterization studies including capacitance-voltage measurements and admittance measurements, and then report initial experiments using a conventional piezoelectric transducer for excitation, with successful detection of signals in an on-axis transmission experiment and successful source localization from phased array performance in an off-axis transmission experiment.

  10. TRAF6 and Src kinase activity regulates Cot activation by IL-1.

    PubMed

    Rodríguez, Cristina; Pozo, Maite; Nieto, Elvira; Fernández, Margarita; Alemany, Susana

    2006-09-01

    Cot is one of the MAP kinase kinase kinases that regulates the ERK1/ERK2 pathway under physiological conditions. Cot is activated by LPS, by inducing its dissociation from the inactive p105 NFkappaB-Cot complex in macrophages. Here, we show that IL-1 promotes a 10-fold increase in endogenous Cot activity and that Cot is the only MAP kinase kinase kinase that activates ERK1/ERK2 in response to this cytokine. Moreover, in cells where the expression of Cot is blocked, IL-1 fails to induce an increase in IL-8 and MIP-1betamRNA levels. The activation of Cot-MKK1-ERK1/ERK2 signalling pathway by IL-1 is dependent on the activity of the transducer protein TRAF6. Most important, IL-1-induced ERK1/ERK2 activation is inhibited by PP1, a known inhibitor of Src tyrosine kinases, but this tyrosine kinase activity is not required for IL-1 to activate other MAP kinases such as p38 and JNK. This Src kinases inhibitor does not block the dissociation and subsequently degradation of Cot in response to IL-1, indicating that other events besides Cot dissociation are required to activate Cot. All these data highlight the specific requirements for activation of the Cot-MKK1-ERK1/ERK2 pathway and provide evidence that Cot controls the functions of IL-1 that are mediated by ERK1/ERK2.

  11. Modulators of Stomatal Lineage Signal Transduction Alter Membrane Contact Sites and Reveal Specialization among ERECTA Kinases.

    PubMed

    Ho, Chin-Min Kimmy; Paciorek, Tomasz; Abrash, Emily; Bergmann, Dominique C

    2016-08-22

    Signal transduction from a cell's surface to its interior requires dedicated signaling elements and a cellular environment conducive to signal propagation. Plant development, defense, and homeostasis rely on plasma membrane receptor-like kinases to perceive endogenous and environmental signals, but little is known about their immediate downstream targets and signaling modifiers. Using genetics, biochemistry, and live-cell imaging, we show that the VAP-RELATED SUPPRESSOR OF TMM (VST) family is required for ERECTA-mediated signaling in growth and cell-fate determination and reveal a role for ERECTA-LIKE2 in modulating signaling by its sister kinases. We show that VSTs are peripheral plasma membrane proteins that can form complexes with integral ER-membrane proteins, thereby potentially influencing the organization of the membrane milieu to promote efficient and differential signaling from the ERECTA-family members to their downstream intracellular targets. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Essential role of protein kinase C delta in platelet signaling, alpha IIb beta 3 activation, and thromboxane A2 release.

    PubMed

    Yacoub, Daniel; Théorêt, Jean-François; Villeneuve, Louis; Abou-Saleh, Haissam; Mourad, Walid; Allen, Bruce G; Merhi, Yahye

    2006-10-06

    The protein kinase C (PKC) family is an essential signaling mediator in platelet activation and aggregation. However, the relative importance of the major platelet PKC isoforms and their downstream effectors in platelet signaling and function remain unclear. Using isolated human platelets, we report that PKCdelta, but not PKCalpha or PKCbeta, is required for collagen-induced phospholipase C-dependent signaling, activation of alpha(IIb)beta(3), and platelet aggregation. Analysis of PKCdelta phosphorylation and translocation to the membrane following activation by both collagen and thrombin indicates that it is positively regulated by alpha(IIb)beta(3) outside-in signaling. Moreover, PKCdelta triggers activation of the mitogen-activated protein kinase-kinase (MEK)/extracellular-signal regulated kinase (ERK) and the p38 MAPK signaling. This leads to the subsequent release of thromboxane A(2), which is essential for collagen-induced but not thrombin-induced platelet activation and aggregation. This study adds new insight to the role of PKCs in platelet function, where PKCdelta signaling, via the MEK/ERK and p38 MAPK pathways, is required for the secretion of thromboxane A(2).

  13. Interplay of autophagy, receptor tyrosine kinase signalling and endocytic trafficking

    PubMed Central

    Fraser, Jane; Cabodevilla, Ainara G.; Simpson, Joanne; Gammoh, Noor

    2017-01-01

    Vesicular trafficking events play key roles in the compartmentalization and proper sorting of cellular components. These events have crucial roles in sensing external signals, regulating protein activities and stimulating cell growth or death decisions. Although mutations in vesicle trafficking players are not direct drivers of cellular transformation, their activities are important in facilitating oncogenic pathways. One such pathway is the sensing of external stimuli and signalling through receptor tyrosine kinases (RTKs). The regulation of RTK activity by the endocytic pathway has been extensively studied. Compelling recent studies have begun to highlight the association between autophagy and RTK signalling. The influence of this interplay on cellular status and its relevance in disease settings will be discussed here. PMID:29233871

  14. An accurate, simple prognostic model consisting of age, JAK2, CALR, and MPL mutation status for patients with primary myelofibrosis.

    PubMed

    Rozovski, Uri; Verstovsek, Srdan; Manshouri, Taghi; Dembitz, Vilma; Bozinovic, Ksenija; Newberry, Kate; Zhang, Ying; Bove, Joseph E; Pierce, Sherry; Kantarjian, Hagop; Estrov, Zeev

    2017-01-01

    In most patients with primary myelofibrosis, one of three mutually exclusive somatic mutations is detected. In approximately 60% of patients, the Janus kinase 2 gene is mutated, in 20%, the calreticulin gene is mutated, and in 5%, the myeloproliferative leukemia virus gene is mutated. Although patients with mutated calreticulin or myeloproliferative leukemia genes have a favorable outcome, and those with none of these mutations have an unfavorable outcome, prognostication based on mutation status is challenging due to the heterogeneous survival of patients with mutated Janus kinase 2. To develop a prognostic model based on mutation status, we screened primary myelofibrosis patients seen at the MD Anderson Cancer Center, Houston, USA, between 2000 and 2013 for the presence of Janus kinase 2, calreticulin, and myeloproliferative leukemia mutations. Of 344 primary myelofibrosis patients, Janus kinase 2 V617F was detected in 226 (66%), calreticulin mutation in 43 (12%), and myeloproliferative leukemia mutation in 16 (5%); 59 patients (17%) were triple-negatives. A 50% cut-off dichotomized Janus kinase 2-mutated patients into those with high Janus kinase 2 V617F allele burden and favorable survival and those with low Janus kinase 2 V617F allele burden and unfavorable survival. Patients with a favorable mutation status (high Janus kinase 2 V617F allele burden/myeloproliferative leukemia/calreticulin mutation) and aged 65 years or under had a median survival of 126 months. Patients with one risk factor (low Janus kinase 2 V617F allele burden/triple-negative or age >65 years) had an intermediate survival duration, and patients aged over 65 years with an adverse mutation status (low Janus kinase 2 V617F allele burden or triple-negative) had a median survival of only 35 months. Our simple and easily applied age- and mutation status-based scoring system accurately predicted the survival of patients with primary myelofibrosis. Copyright© Ferrata Storti Foundation.

  15. Spiropyran-Decorated SiO₂-Pt Janus Micromotor: Preparation and Light-Induced Dynamic Self-Assembly and Disassembly.

    PubMed

    Zhang, Qilu; Dong, Renfeng; Chang, Xueyi; Ren, Biye; Tong, Zhen

    2015-11-11

    The controlled self-assembly of self-propelled Janus micromotors may give the micromotors some potential applications in many fields. In this work, we design a kind of SiO2-Pt Janus catalytic micromotor functionalized by spiropyran (SP) moieties on the surface of the SiO2 hemisphere. The spiropyran-modified SiO2-Pt Janus micromotor exhibits autonomous self-propulsion in the presence of hydrogen peroxide fuel in N,N-dimethylformamide (DMF)/H2O (1:1 in volume) mixture. We demonstrate that the self-propelled Janus micromotors can dynamically assemble into multiple motors because of the electrostatic attractions and π-π stacking between MC molecules induced by UV light irradiation (λ = 365 nm) and also quickly disassemble into mono motors when the light is switched to green light (λ = 520 nm) for the first time. Furthermore, the assembled Janus motors can move together automatically with different motion patterns propelled by the hydrogen peroxide fuels upon UV irradiation. The work provides a new approach not only to the development of the potential application of Janus motors but also to the fundamental science of reversible self-assembly and disassembly of Janus micromotors.

  16. The Xanthomonas euvesicatoria type III effector XopAU is an active protein kinase that manipulates plant MAP kinase signaling.

    PubMed

    Teper, Doron; Girija, Anil Madhusoodana; Bosis, Eran; Popov, Georgy; Savidor, Alon; Sessa, Guido

    2018-01-01

    The Gram-negative bacterium Xanthomonas euvesicatoria (Xe) is the causal agent of bacterial spot disease of pepper and tomato. Xe delivers effector proteins into host cells through the type III secretion system to promote disease. Here, we show that the Xe effector XopAU, which is conserved in numerous Xanthomonas species, is a catalytically active protein kinase and contributes to the development of disease symptoms in pepper plants. Agrobacterium-mediated expression of XopAU in host and non-host plants activated typical defense responses, including MAP kinase phosphorylation, accumulation of pathogenesis-related (PR) proteins and elicitation of cell death, that were dependent on the kinase activity of the effector. XopAU-mediated cell death was not dependent on early signaling components of effector-triggered immunity and was also observed when the effector was delivered into pepper leaves by Xanthomonas campestris pv. campestris, but not by Xe. Protein-protein interaction studies in yeast and in planta revealed that XopAU physically interacts with components of plant immunity-associated MAP kinase cascades. Remarkably, XopAU directly phosphorylated MKK2 in vitro and enhanced its phosphorylation at multiple sites in planta. Consistent with the notion that MKK2 is a target of XopAU, silencing of the MKK2 homolog or overexpression of the catalytically inactive mutant MKK2K99R in N. benthamiana plants reduced XopAU-mediated cell death and MAPK phosphorylation. Furthermore, yeast co-expressing XopAU and MKK2 displayed reduced growth and this phenotype was dependent on the kinase activity of both proteins. Together, our results support the conclusion that XopAU contributes to Xe disease symptoms in pepper plants and manipulates host MAPK signaling through phosphorylation and activation of MKK2.

  17. Barcoding of GPCR trafficking and signaling through the various trafficking roadmaps by compartmentalized signaling networks.

    PubMed

    Bahouth, Suleiman W; Nooh, Mohammed M

    2017-08-01

    Proper signaling by G protein coupled receptors (GPCR) is dependent on the specific repertoire of transducing, enzymatic and regulatory kinases and phosphatases that shape its signaling output. Activation and signaling of the GPCR through its cognate G protein is impacted by G protein-coupled receptor kinase (GRK)-imprinted "barcodes" that recruit β-arrestins to regulate subsequent desensitization, biased signaling and endocytosis of the GPCR. The outcome of agonist-internalized GPCR in endosomes is also regulated by sequence motifs or "barcodes" within the GPCR that mediate its recycling to the plasma membrane or retention and eventual degradation as well as its subsequent signaling in endosomes. Given the vast number of diverse sequences in GPCR, several trafficking mechanisms for endosomal GPCR have been described. The majority of recycling GPCR, are sorted out of endosomes in a "sequence-dependent pathway" anchored around a type-1 PDZ-binding module found in their C-tails. For a subset of these GPCR, a second "barcode" imprinted onto specific GPCR serine/threonine residues by compartmentalized kinase networks was required for their efficient recycling through the "sequence-dependent pathway". Mutating the serine/threonine residues involved, produced dramatic effects on GPCR trafficking, indicating that they played a major role in setting the trafficking itinerary of these GPCR. While endosomal SNX27, retromer/WASH complexes and actin were required for efficient sorting and budding of all these GPCR, additional proteins were required for GPCR sorting via the second "barcode". Here we will review recent developments in GPCR trafficking in general and the human β 1 -adrenergic receptor in particular across the various trafficking roadmaps. In addition, we will discuss the role of GPCR trafficking in regulating endosomal GPCR signaling, which promote biochemical and physiological effects that are distinct from those generated by the GPCR signal transduction

  18. Simultaneous muscle force and displacement transducer

    NASA Technical Reports Server (NTRS)

    Feldstein, C.; Lewis, G. W.; Culler, V. H. (Inventor)

    1980-01-01

    A myocardial transducer for simultaneously measuring force and displacement within a very small area of myocardium is disclosed. The transducer comprised of an elongated body forked at one end to form an inverted Y shaped beam with each branch of the beam constituting a low compliant tine for penetrating the myocardium to a predetermined depth. Bonded to one of the low compliance tines is a small piezoresistive element for converting a force acting on the beam into an electrical signal. A third high compliant tine of the transducer, which measures displacement of the myocardium in a direction in line with the two low compliant tines, is of a length that just pierces the surface membrane. A small piezoresistive element is bonded to the third tine at its upper end where its bending is greatest. Displacement of the myocardium causes a deformation in curvature of the third tine, and the second small piezoresistive element bonded to the surface of its curved end converts its deformation into an electrical signal.

  19. A Novel Positive Feedback Loop Mediated by the Docking Protein Gab1 and Phosphatidylinositol 3-Kinase in Epidermal Growth Factor Receptor Signaling

    PubMed Central

    Rodrigues, Gerard A.; Falasca, Marco; Zhang, Zhongtao; Ong, Siew Hwa; Schlessinger, Joseph

    2000-01-01

    The Gab1 protein is tyrosine phosphorylated in response to various growth factors and serves as a docking protein that recruits a number of downstream signaling proteins, including phosphatidylinositol 3-kinase (PI-3 kinase). To determine the role of Gab1 in signaling via the epidermal growth factor (EGF) receptor (EGFR) we tested the ability of Gab1 to associate with and modulate signaling by this receptor. We show that Gab1 associates with the EGFR in vivo and in vitro via pTyr sites 1068 and 1086 in the carboxy-terminal tail of the receptor and that overexpression of Gab1 potentiates EGF-induced activation of the mitogen-activated protein kinase and Jun kinase signaling pathways. A mutant of Gab1 unable to bind the p85 subunit of PI-3 kinase is defective in potentiating EGFR signaling, confirming a role for PI-3 kinase as a downstream effector of Gab1. Inhibition of PI-3 kinase by a dominant-interfering mutant of p85 or by Wortmannin treatment similarly impairs Gab1-induced enhancement of signaling via the EGFR. The PH domain of Gab1 was shown to bind specifically to phosphatidylinositol 3,4,5-triphosphate [PtdIns(3,4,5)P3], a product of PI-3 kinase, and is required for activation of Gab1-mediated enhancement of EGFR signaling. Moreover, the PH domain mediates Gab1 translocation to the plasma membrane in response to EGF and is required for efficient tyrosine phosphorylation of Gab1 upon EGF stimulation. In addition, overexpression of Gab1 PH domain blocks Gab1 potentiation of EGFR signaling. Finally, expression of the gene for the lipid phosphatase PTEN, which dephosphorylates PtdIns(3,4,5)P3, inhibits EGF signaling and translocation of Gab1 to the plasma membrane. These results reveal a novel positive feedback loop, modulated by PTEN, in which PI-3 kinase functions as both an upstream regulator and a downstream effector of Gab1 in signaling via the EGFR. PMID:10648629

  20. Anisotropic Janus Si nanopillar arrays as a microfluidic one-way valve for gas-liquid separation

    NASA Astrophysics Data System (ADS)

    Wang, Tieqiang; Chen, Hongxu; Liu, Kun; Li, Yang; Xue, Peihong; Yu, Ye; Wang, Shuli; Zhang, Junhu; Kumacheva, Eugenia; Yang, Bai

    2014-03-01

    In this paper, we demonstrate a facile strategy for the fabrication of a one-way valve for microfluidic (MF) systems. The micro-valve was fabricated by embedding arrays of Janus Si elliptical pillars (Si-EPAs) with anisotropic wettability into a MF channel fabricated in poly(dimethylsiloxane) (PDMS). Two sides of the Janus pillar are functionalized with molecules with distinct surface energies. The ability of the Janus pillar array to act as a valve was proved by investigating the flow behaviour of water in a T-shaped microchannel at different flow rates and pressures. In addition, the one-way valve was used to achieve gas-liquid separation. We believe that the Janus Si-EPAs modified by specific surface functionalization provide a new strategy to control the flow and motion of fluids in MF channels.In this paper, we demonstrate a facile strategy for the fabrication of a one-way valve for microfluidic (MF) systems. The micro-valve was fabricated by embedding arrays of Janus Si elliptical pillars (Si-EPAs) with anisotropic wettability into a MF channel fabricated in poly(dimethylsiloxane) (PDMS). Two sides of the Janus pillar are functionalized with molecules with distinct surface energies. The ability of the Janus pillar array to act as a valve was proved by investigating the flow behaviour of water in a T-shaped microchannel at different flow rates and pressures. In addition, the one-way valve was used to achieve gas-liquid separation. We believe that the Janus Si-EPAs modified by specific surface functionalization provide a new strategy to control the flow and motion of fluids in MF channels. Electronic supplementary information (ESI) available: The XPS spectrum of the as-prepared Janus arrays after the MHA modification; the SEM images of the PFS-MHA Janus Si pillar arrays fabricated through oblique evaporation of gold along the short axis of the elliptical pillars; images of the cross-shaped MF channel and Rhodamine aqueous solution injecting in a cross-shaped MF

  1. Functional potentiation of leptin-signal transducer and activator of transcription 3 signaling by the androgen receptor.

    PubMed

    Fan, WuQiang; Yanase, Toshihiko; Nishi, Yoshihiro; Chiba, Seiichi; Okabe, Taijiro; Nomura, Masatoshi; Yoshimatsu, Hironobu; Kato, Shigeaki; Takayanagi, Ryoichi; Nawata, Hajime

    2008-12-01

    Hypogonadism is associated with increased fat mass and dysregulation of metabolic homeostasis in men. Our previous study revealed that androgen receptor (AR)-null male mice (ARL-/Y) develop late-onset obesity and are leptin-resistant. The present study evaluated how hypothalamic AR contributes to central leptin-signal transducer and activator of transcription 3 (STAT3) signaling. We evaluated leptin action in wild-type and ARL-/Y mice, the anatomic co-relationship between AR and leptin signaling in the hypothalamus, and the effects of AR on leptin-mediated STAT3 transactivation and nuclear translocation. AR deletion in male mice results in a weaker leptin-induced suppression of food intake and body weight drop even before the onset of overt obesity. In wild-type male but not female mice, AR was highly expressed in various hypothalamic nuclei that also expressed the long-form leptin receptor (OBRB) and co-resided with OBRB directly in the arcuate neurons. In vitro, AR significantly enhanced STAT3-mediated transcription of leptin target genes including POMC and SOCS3. This effect relied on the AR N-terminal activation function-1 (AF-1) domain and was specific to AR in that none of the other sex steroid hormone receptors tested showed similar effects. AR enhanced the low concentrations of leptin-induced STAT3 nuclear translocation in vitro, and ARL-/Y mice receiving leptin had impaired STAT3 nuclear localization in the arcuate neurons. These findings indicate that AR in the hypothalamus functions as a regulator of central leptin-OBRB-STAT3 signaling and has a physiological role in energy homeostasis and metabolic regulation in male mice.

  2. Transducer selection and application in magnetoacoustic tomography with magnetic induction

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhou, Yuqi; Wang, Jiawei; Ma, Qingyu, E-mail: maqingyu@njnu.edu.cn

    2016-03-07

    As an acoustic receiver, transducer plays a vital role in signal acquisition and image reconstruction for magnetoacoustic tomography with magnetic induction (MAT-MI). In order to optimize signal acquisition, the expressions of acoustic pressure detection and waveform collection are theoretically studied based on the radiation theory of acoustic dipole and the reception pattern of transducer. Pressure distributions are simulated for a cylindrical phantom model using a planar piston transducer with different radii and bandwidths. The proposed theory is also verified by the experimental measurements of acoustic waveform detection for an aluminum foil cylinder. It is proved that acoustic pressure with sharpmore » and clear boundary peaks can be detected by the large-radius transducer with wide bandwidth, reflecting the differential of the induced Lorentz force accurately, which is helpful for precise conductivity reconstruction. To detect acoustic pressure with acceptable pressure amplitude, peak pressure ratio, amplitude ratio, and improved signal to noise ratio, the scanning radius of 5–10 times the radius of the object should be selected to improve the accuracy of image reconstruction. This study provides a theoretical and experimental basis for transducer selection and application in MAT-MI to obtain reconstructed images with improved resolution and definition.« less

  3. The Ste20 Family Kinases MAP4K4, MINK1, and TNIK Converge to Regulate Stress-Induced JNK Signaling in Neurons.

    PubMed

    Larhammar, Martin; Huntwork-Rodriguez, Sarah; Rudhard, York; Sengupta-Ghosh, Arundhati; Lewcock, Joseph W

    2017-11-15

    The c-Jun- N -terminal kinase (JNK) signaling pathway regulates nervous system development, axon regeneration, and neuronal degeneration after acute injury or in chronic neurodegenerative disease. Dual leucine zipper kinase (DLK) is required for stress-induced JNK signaling in neurons, yet the factors that initiate DLK/JNK pathway activity remain poorly defined. In the present study, we identify the Ste20 kinases MAP4K4, misshapen-like kinase 1 (MINK1 or MAP4K6) and TNIK Traf2- and Nck-interacting kinase (TNIK or MAP4K7), as upstream regulators of DLK/JNK signaling in neurons. Using a trophic factor withdrawal-based model of neurodegeneration in both male and female embryonic mouse dorsal root ganglion neurons, we show that MAP4K4, MINK1, and TNIK act redundantly to regulate DLK activation and downstream JNK-dependent phosphorylation of c-Jun in response to stress. Targeting MAP4K4, MINK1, and TNIK, but not any of these kinases individually, is sufficient to protect neurons potently from degeneration. Pharmacological inhibition of MAP4Ks blocks stabilization and phosphorylation of DLK within axons and subsequent retrograde translocation of the JNK signaling complex to the nucleus. These results position MAP4Ks as important regulators of the DLK/JNK signaling pathway. SIGNIFICANCE STATEMENT Neuronal degeneration occurs in disparate circumstances: during development to refine neuronal connections, after injury to clear damaged neurons, or pathologically during disease. The dual leucine zipper kinase (DLK)/c-Jun- N -terminal kinase (JNK) pathway represents a conserved regulator of neuronal injury signaling that drives both neurodegeneration and axon regeneration, yet little is known about the factors that initiate DLK activity. Here, we uncover a novel role for a subfamily of MAP4 kinases consisting of MAP4K4, Traf2- and Nck-interacting kinase (TNIK or MAP4K7), and misshapen-like kinase 1 (MINK1 or MAP4K6) in regulating DLK/JNK signaling in neurons. Inhibition of

  4. Combined distributed and concentrated transducer network for failure indication

    NASA Astrophysics Data System (ADS)

    Ostachowicz, Wieslaw; Wandowski, Tomasz; Malinowski, Pawel

    2010-03-01

    In this paper algorithm for discontinuities localisation in thin panels made of aluminium alloy is presented. Mentioned algorithm uses Lamb wave propagation methods for discontinuities localisation. Elastic waves were generated and received using piezoelectric transducers. They were arranged in concentrated arrays distributed on the specimen surface. In this way almost whole specimen could be monitored using this combined distributed-concentrated transducer network. Excited elastic waves propagate and reflect from panel boundaries and discontinuities existing in the panel. Wave reflection were registered through the piezoelectric transducers and used in signal processing algorithm. Proposed processing algorithm consists of two parts: signal filtering and extraction of obstacles location. The first part was used in order to enhance signals by removing noise from them. Second part allowed to extract features connected with wave reflections from discontinuities. Extracted features damage influence maps were a basis to create damage influence maps. Damage maps indicated intensity of elastic wave reflections which corresponds to obstacles coordinates. Described signal processing algorithms were implemented in the MATLAB environment. It should be underlined that in this work results based only on experimental signals were presented.

  5. Supersymmetric Janus solutions of dyonic ISO(7)-gauged N = 8 supergravity

    NASA Astrophysics Data System (ADS)

    Suh, Minwoo

    2018-04-01

    We study supersymmetric Janus solutions of dyonic ISO(7)-gauged N = 8 supergravity. We mostly find Janus solutions flowing to 3d N = 8 SYM phase which is the worldvolume theory on D2-branes and non-conformal. There are also solutions flowing from the critical points which are dual to 3d SCFTs from deformations of the D2-brane theory.

  6. Near infrared-modulated propulsion of catalytic Janus polymer multilayer capsule motors.

    PubMed

    Wu, Yingjie; Si, Tieyan; Lin, Xiankun; He, Qiang

    2015-01-11

    The use of a near-infrared (NIR) laser for reversible modulation of a bubble-driven Janus polymer capsule motor is demonstrated. This process was mediated through illumination of the metal face of the Janus capsule motor at the critical concentration of peroxide fuel. Such an effective control of the propulsion of chemically powered microengines holds a considerable promise for diverse applications.

  7. Regulation of Cardiac Stress Signaling by Protein Kinase D1

    PubMed Central

    Harrison, Brooke C.; Kim, Mi-Sung; van Rooij, Eva; Plato, Craig F.; Papst, Philip J.; Vega, Rick B.; McAnally, John A.; Richardson, James A.; Bassel-Duby, Rhonda; Olson, Eric N.; McKinsey, Timothy A.

    2006-01-01

    In response to pathological stresses such as hypertension or myocardial infarction, the heart undergoes a remodeling process that is associated with myocyte hypertrophy, myocyte death, and fibrosis. Histone deacetylase 5 (HDAC5) is a transcriptional repressor of cardiac remodeling that is subject to phosphorylation-dependent neutralization in response to stress signaling. Recent studies have suggested a role for protein kinase C (PKC) and its downstream effector, protein kinase D1 (PKD1), in the control of HDAC5 phosphorylation. While PKCs are well-documented regulators of cardiac signaling, the function of PKD1 in heart muscle remains unclear. Here, we demonstrate that PKD1 catalytic activity is stimulated in cardiac myocytes by diverse hypertrophic agonists that signal through G protein-coupled receptors (GPCRs) and Rho GTPases. PKD1 activation in cardiomyocytes occurs through PKC-dependent and -independent mechanisms. In vivo, cardiac PKD1 is activated in multiple rodent models of pathological cardiac remodeling. PKD1 activation correlates with phosphorylation-dependent nuclear export of HDAC5, and reduction of endogenous PKD1 expression with small interfering RNA suppresses HDAC5 shuttling and associated cardiomyocyte growth. Conversely, ectopic overexpression of constitutively active PKD1 in mouse heart leads to dilated cardiomyopathy. These findings support a role for PKD1 in the control of pathological remodeling of the heart via its ability to phosphorylate and neutralize HDAC5. PMID:16648482

  8. Janus Colloids Actively Rotating on the Surface of Water.

    PubMed

    Wang, Xiaolu; In, Martin; Blanc, Christophe; Würger, Alois; Nobili, Maurizio; Stocco, Antonio

    2017-12-05

    Biological or artificial microswimmers move performing trajectories of different kinds such as rectilinear, circular, or spiral ones. Here, we report on circular trajectories observed for active Janus colloids trapped at the air-water interface. Circular motion is due to asymmetric and nonuniform surface properties of the particles caused by fabrication. Motion persistence is enhanced by the partial wetted state of the Janus particles actively moving in two dimensions at the air-water interface. The slowing down of in-plane and out-of-plane rotational diffusions is described and discussed.

  9. Hypoxia increases the heterogeneity of melanoma cell populations and affects the response to vemurafenib.

    PubMed

    Pucciarelli, Daniela; Lengger, Nina; Takáčová, Martina; Csaderova, Lucia; Bartosova, Maria; Breiteneder, Heimo; Pastorekova, Silvia; Hafner, Christine

    2016-04-01

    A hypoxic microenvironment is one of the predominant reasons for incomplete response to melanoma treatment. Vemurafenib, which targets the mutated BRAF-V600 kinase, improves melanoma patient survival, however, resistance invariably develops. The present study evaluated the effect of hypoxia on three BRAF-V600E mutant melanoma cell lines, M14, A375 and 518A2, treated with vemurafenib. Compared with the other two cell lines, hypoxic vemurafenib-treated A375 cells exhibited an enhanced cell proliferation rate and migratory capacity compared with normoxic vemurafenib-treated A375 cells. Immunoblotting analyses revealed that the expression levels of hypoxia inducible factor (HIF)1α and carbonic anhydrase IX were reduced in vemurafenib‑treated M14 and 518A2 cells, however, not in A375 cells. The expression levels of the mitogen‑activated protein kinase, Janus kinase-signal transducer and activator of transcription, and phosphatidylinositol-4,5-bisphosphate 3‑kinase signaling pathway proteins revealed a cell‑type specific response to vemurafenib and hypoxia. Knockdown experiments of HIF1α performed in hypoxic A375 cells decreased the expression of phosphorylated (p‑)protein kinase B, which was restored following vemurafenib treatment, and increased the expression of p‑extracellular‑signal‑regulated kinases. Therefore, three melanoma cell lines responded to vemurafenib under hypoxia in a cell type‑specific manner, suggesting that a subset of cells provides a treatment-resistant pool, from which disease relapse may originate. These data confirmed that vemurafenib may be successful in treating the proliferating cells, whereas the non‑proliferating subpopulation must be addressed by a combination of vemurafenib with other treatment strategies.

  10. Integration of light and metabolic signals for stem cell activation at the shoot apical meristem

    PubMed Central

    Pfeiffer, Anne; Janocha, Denis; Dong, Yihan; Medzihradszky, Anna; Schöne, Stefanie; Daum, Gabor; Suzaki, Takuya; Forner, Joachim; Langenecker, Tobias; Rempel, Eugen; Schmid, Markus; Wirtz, Markus; Hell, Rüdiger; Lohmann, Jan U

    2016-01-01

    A major feature of embryogenesis is the specification of stem cell systems, but in contrast to the situation in most animals, plant stem cells remain quiescent until the postembryonic phase of development. Here, we dissect how light and metabolic signals are integrated to overcome stem cell dormancy at the shoot apical meristem. We show on the one hand that light is able to activate expression of the stem cell inducer WUSCHEL independently of photosynthesis and that this likely involves inter-regional cytokinin signaling. Metabolic signals, on the other hand, are transduced to the meristem through activation of the TARGET OF RAPAMYCIN (TOR) kinase. Surprisingly, TOR is also required for light signal dependent stem cell activation. Thus, the TOR kinase acts as a central integrator of light and metabolic signals and a key regulator of stem cell activation at the shoot apex. DOI: http://dx.doi.org/10.7554/eLife.17023.001 PMID:27400267

  11. Essential role of protein kinase C ζ in transducing a motility signal induced by superoxide and a chemotactic peptide, fMLP

    PubMed Central

    Kuribayashi, Kageaki; Nakamura, Kiminori; Tanaka, Maki; Sato, Tsutomu; Kato, Junji; Sasaki, Katsunori; Takimoto, Rishu; Kogawa, Katsuhisa; Terui, Takeshi; Takayama, Tetsuji; Onuma, Takayuki; Matsunaga, Takuya; Niitsu, Yoshiro

    2007-01-01

    Under various pathological conditions, including infection, malignancy, and autoimmune diseases, tissues are incessantly exposed to reactive oxygen species produced by infiltrating inflammatory cells. We show augmentation of motility associated with morphological changes of human squamous carcinoma SASH1 cells, human peripheral monocytes (hPMs), and murine macrophage-like cell line J774.1 by superoxide stimulation. We also disclose that motility of hPMs and J774.1 induced by a chemotactic peptide (N-formyl-methionyl-leucyl-phenylalanine [fMLP]) was inhibited by superoxide dismutase or N-acetylcystein, indicating stimulation of motility by superoxide generated by fMLP stimulation. In these cells, protein kinase C (PKC) ζ was activated to phosphorylate RhoGDI-1, which liberated RhoGTPases, leading to their activation. These events were inhibited by dominant-negative PKCζ in SASH1 cells, myristoylated PKCζ peptides in hPMs and J774.1, or a specific inhibitor of RhoGTPase in SASH1, hPMs, and J774.1. These results suggest a new approach for manipulation of inflammation as well as tumor cell invasion by targeting this novel signaling pathway. PMID:17389234

  12. E93 predominantly transduces 20-hydroxyecdysone signaling to induce autophagy and caspase activity in Drosophila fat body.

    PubMed

    Liu, Hanhan; Wang, Jin; Li, Sheng

    2014-02-01

    During the larval-prepupal transition in Drosophila, a balancing crosstalk occurs between autophagy and caspase activity in the remodeling fat body: the inhibition of autophagy induces caspase activity and the inhibition of caspases induces autophagy. Both autophagy and caspase activity are induced by a pulse of molting hormone (20-hydroxyecdysone, 20E) via the 20E nuclear receptor complex, EcR-USP. We here demonstrate that E93, a 20E primary-response gene encoding an HTH transcription factor, predominantly transduces 20E signaling to induce autophagy and caspase activity in the remodeling fat body. RNAi knockdown or mutation of E93 blocks autophagy and caspase activity, E93 overexpression induces them both, while E93 overexpression has a better rescuing effect on the inhibition of autophagy than caspase activity caused by EcR(DN) overexpression. At the transcriptional level, E93 not only greatly impacts the 20E-triggered transcriptional cascade, but also upregulates essential autophagy and apoptosis genes. Meanwhile, at the phosphorylational level, E93 blocks the PI3K-TORC1 signaling to initiate autophagy. Taken together, we conclude that autophagy and caspase activity are induced by 20E and predominantly transduced by E93 in the remodeling fat body of Drosophila. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Mammary ductal growth is impaired in mice lacking leptin-dependent signal transducer and activator of transcription 3 signaling.

    PubMed

    Thorn, Stephanie R; Giesy, Sarah L; Myers, Martin G; Boisclair, Yves R

    2010-08-01

    Mice lacking leptin (ob/ob) or its full-length receptor (db/db) are obese and reproductively incompetent. Fertility, pregnancy, and lactation are restored, respectively, in ob/ob mice treated with leptin through mating, d 6.5 post coitum, and pregnancy. Therefore, leptin signaling is needed for lactation, but the timing of its action and the affected mammary process remain unknown. To address this issue, we used s/s mice lacking only leptin-dependent signal transducer and activator of transcription (STAT)3 signaling. These mice share many features with db/db mice, including obesity, but differ by retaining sufficient activity of the hypothalamic-pituitary-ovarian axis to support reproduction. The s/s mammary epithelium was normal at 3 wk of age but failed to expand through the mammary fat pad (MFP) during the subsequent pubertal period. Ductal growth failure was not corrected by estrogen therapy and did not relate to inadequate IGF-I production by the MFP or to the need for epithelial or stromal leptin-STAT3 signaling. Ductal growth failure coincided with adipocyte hypertrophy and increased MFP production of leptin, TNFalpha, and IL6. These cytokines, however, were unable to inhibit the proliferation of a collection of mouse mammary epithelial cell lines. In conclusion, the very first step of postnatal mammary development fails in s/s mice despite sufficient estrogen IGF-I and an hypothalamic-pituitary-ovarian axis capable of supporting reproduction. This failure is not caused by mammary loss of leptin-dependent STAT3 signaling or by the development of inflammation. These data imply the existence of an unknown mechanism whereby leptin-dependent STAT3 signaling and obesity alter mammary ductal development.

  14. Visible-Light-Driven BiOI-Based Janus Micromotor in Pure Water.

    PubMed

    Dong, Renfeng; Hu, Yan; Wu, Yefei; Gao, Wei; Ren, Biye; Wang, Qinglong; Cai, Yuepeng

    2017-02-08

    Light-driven synthetic micro-/nanomotors have attracted considerable attention due to their potential applications and unique performances such as remote motion control and adjustable velocity. Utilizing harmless and renewable visible light to supply energy for micro-/nanomotors in water represents a great challenge. In view of the outstanding photocatalytic performance of bismuth oxyiodide (BiOI), visible-light-driven BiOI-based Janus micromotors have been developed, which can be activated by a broad spectrum of light, including blue and green light. Such BiOI-based Janus micromotors can be propelled by photocatalytic reactions in pure water under environmentally friendly visible light without the addition of any other chemical fuels. The remote control of photocatalytic propulsion by modulating the power of visible light is characterized by velocity and mean-square displacement analysis of optical video recordings. In addition, the self-electrophoresis mechanism has been confirmed for such visible-light-driven BiOI-based Janus micromotors by demonstrating the effects of various coated layers (e.g., Al 2 O 3 , Pt, and Au) on the velocity of motors. The successful demonstration of visible-light-driven Janus micromotors holds a great promise for future biomedical and environmental applications.

  15. Matrix-specific protein kinase A signaling regulates p21 activated kinase activation by flow in endothelial cells

    PubMed Central

    Funk, Steven Daniel; Yurdagul, Arif; Green, Jonette M.; Jhaveri, Krishna A.; Schwartz, Martin Alexander; Orr, A. Wayne

    2010-01-01

    Rationale Atherosclerosis is initiated by blood flow patterns that activate inflammatory pathways in endothelial cells. Activation of inflammatory signaling by fluid shear stress is highly dependent on the composition of the subendothelial extracellular matrix. The basement membrane proteins laminin and collagen found in normal vessels suppress flow-induced p21 activated kinase (PAK) and NF-κB activation. By contrast, the provisional matrix proteins fibronectin and fibrinogen found in wounded or inflamed vessels support flow-induced PAK and NF-κB activation. PAK mediates both flow-induced permeability and matrix-specific activation of NF-κB. Objective To elucidate the mechanisms regulating matrix-specific PAK activation. Methods and Results We now show that matrix composition does not affect the upstream pathway by which flow activates PAK (integrin activation, Rac). Instead basement membrane proteins enhance flow-induced protein kinase A (PKA) activation, which suppresses PAK. Inhibiting PKA restored flow-induced PAK and NF-κB activation in cells on basement membrane proteins, whereas stimulating PKA inhibited flow-induced activation of inflammatory signaling in cells on fibronectin. PKA suppressed inflammatory signaling through PAK inhibition. Activating PKA by injection of the PGI2 analog iloprost reduced PAK activation and inflammatory gene expression at sites of disturbed flow in vivo, whereas inhibiting PKA by PKI injection enhanced PAK activation and inflammatory gene expression. Inhibiting PAK prevented the enhancement of inflammatory gene expression by PKI. Conclusions Basement membrane proteins inhibit inflammatory signaling in endothelial cells via PKA-dependent inhibition of PAK. PMID:20224042

  16. The peroxisome proliferator-activated receptor (PPAR) β/δ agonist GW501516 inhibits IL-6-induced signal transducer and activator of transcription 3 (STAT3) activation and insulin resistance in human liver cells.

    PubMed

    Serrano-Marco, L; Barroso, E; El Kochairi, I; Palomer, X; Michalik, L; Wahli, W; Vázquez-Carrera, M

    2012-03-01

    IL-6 induces insulin resistance by activating signal transducer and activator of transcription 3 (STAT3) and upregulating the transcription of its target gene SOCS3. Here we examined whether the peroxisome proliferator-activated receptor (PPAR)β/δ agonist GW501516 prevented activation of the IL-6-STAT3-suppressor of cytokine signalling 3 (SOCS3) pathway and insulin resistance in human hepatic HepG2 cells. Studies were conducted with human HepG2 cells and livers from mice null for Pparβ/δ (also known as Ppard) and wild-type mice. GW501516 prevented IL-6-dependent reduction in insulin-stimulated v-akt murine thymoma viral oncogene homologue 1 (AKT) phosphorylation and in IRS-1 and IRS-2 protein levels. In addition, treatment with this drug abolished IL-6-induced STAT3 phosphorylation of Tyr⁷⁰⁵ and Ser⁷²⁷ and prevented the increase in SOCS3 caused by this cytokine. Moreover, GW501516 prevented IL-6-dependent induction of extracellular-related kinase 1/2 (ERK1/2), a serine-threonine protein kinase involved in serine STAT3 phosphorylation; the livers of Pparβ/δ-null mice showed increased Tyr⁷⁰⁵- and Ser⁷²⁷-STAT3 as well as phospho-ERK1/2 levels. Furthermore, drug treatment prevented the IL-6-dependent reduction in phosphorylated AMP-activated protein kinase (AMPK), a kinase reported to inhibit STAT3 phosphorylation on Tyr⁷⁰⁵. In agreement with the recovery in phospho-AMPK levels observed following GW501516 treatment, this drug increased the AMP/ATP ratio and decreased the ATP/ADP ratio. Overall, our findings show that the PPARβ/δ activator GW501516 prevents IL-6-induced STAT3 activation by inhibiting ERK1/2 phosphorylation and preventing the reduction in phospho-AMPK levels. These effects of GW501516 may contribute to the prevention of cytokine-induced insulin resistance in hepatic cells.

  17. Ruxolitinib for the Treatment of Patients With Polycythemia Vera

    PubMed Central

    Kiladjian, Jean-Jacques; Winton, Elliott F.; Talpaz, Moshe; Verstovsek, Srdan

    2015-01-01

    SUMMARY Polycythemia vera (PV) is a hematopoietic proliferative disorder associated with Janus-associated kinase (JAK)/signal transducer and activator of transcription (STAT) pathway dysregulation resulting in erythrocytosis and, possibly, leukocytosis and thrombocytosis. Patients diagnosed with PV experience a broad range of symptoms associated with a reduced quality of life, often develop splenomegaly, and have an increased risk of death compared to age-matched subjects without PV. Current treatment options, notably hydroxyurea, help with disease management; however, insufficient efficacy or progressive resistance occurs in some patients, highlighting the need for new treatment options. Ruxolitinib is an oral JAK1/JAK2 inhibitor that has been evaluated in phase 2 and 3 clinical trials in patients with PV who are intolerant of or resistant to hydroxyurea. In this setting, ruxolitinib treatment has demonstrated normalization of blood cell counts, reduction in splenomegaly, and improvements in PV-related symptom burden. PMID:25980454

  18. Temperature transducer has high output, is time stable

    NASA Technical Reports Server (NTRS)

    Follett, W. H.

    1965-01-01

    Compact, lightweight temperature transducer requires no amplification of its output signal and is time stable. It uses the temperature-dependent characteristics of a silicon transistor to provide a zero-to-five-volt signal proportional to temperature.

  19. The tight junction protein ZO-2 and Janus kinase 1 mediate intercellular communications in vascular smooth muscle cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tkachuk, Natalia; Tkachuk, Sergey; Patecki, Margret

    2011-07-08

    Highlights: {yields} The tight junction protein ZO-2 associates with Jak1 in vascular smooth muscle cells via ZO-2 N-terminal fragment. {yields} Jak1 mediates ZO-2 tyrosine phosphorylation and ZO-2 localization to the sites of homotypic intercellular contacts. {yields} The urokinase receptor uPAR regulates ZO-2/Jak1 functional association. {yields} The ZO-2/Jak1/uPAR signaling complex is required for vascular smooth muscle cells functional network formation. -- Abstract: Recent evidence points to a multifunctional role of ZO-2, the tight junction protein of the MAGUK (membrane-associated guanylate kinase-like) family. Though ZO-2 has been found in cell types lacking tight junction structures, such as vascular smooth muscle cells (VSMC),more » little is known about ZO-2 function in these cells. We provide evidence that ZO-2 mediates specific homotypic cell-to-cell contacts between VSMC. Using mass spectrometry we found that ZO-2 is associated with the non-receptor tyrosine kinase Jak1. By generating specific ZO-2 constructs we further found that the N-terminal fragment of ZO-2 molecule is responsible for this interaction. Adenovirus-based expression of Jak1 inactive mutant demonstrated that Jak1 mediates ZO-2 tyrosine phosphorylation. By means of RNA silencing, expression of Jak1 mutant form and fluorescently labeled ZO-2 fusion protein we further specified that active Jak1, but not Jak1 inactive mutant, mediates ZO-2 localization to the sites of intercellular contacts. We identified the urokinase receptor uPAR as a pre-requisite for these cellular events. Functional requirement of the revealed signaling complex for VSMC network formation was confirmed in experiments using Matrigel and in contraction assay. Our findings imply involvement of the ZO-2 tight junction independent signaling complex containing Jak1 and uPAR in VSMC intercellular communications. This mechanism may contribute to vascular remodeling in occlusive cardiovascular diseases and in

  20. Molecular pathways: targeting RAC-p21-activated serine-threonine kinase signaling in RAS-driven cancers.

    PubMed

    Baker, Nicole M; Yee Chow, Hoi; Chernoff, Jonathan; Der, Channing J

    2014-09-15

    Cancers driven by oncogenic Ras proteins encompass some of the most deadly human cancer types, and there is a pressing need to develop therapies for these diseases. Although recent studies suggest that mutant Ras proteins may yet be druggable, the most promising and advanced efforts involve inhibitors of Ras effector signaling. Most efforts to target Ras signaling have been aimed at the ERK mitogen-activated protein kinase and the phosphoinositide 3-kinase signaling networks. However, to date, no inhibitors of these Ras effector pathways have been effective against RAS-mutant cancers. This ineffectiveness is due, in part, to the involvement of additional effectors in Ras-dependent cancer growth, such as the Rac small GTPase and the p21-activated serine-threonine kinases (PAK). PAK proteins are involved in many survival, cell motility, and proliferative pathways in the cell and may present a viable new target in Ras-driven cancers. In this review, we address the role and therapeutic potential of Rac and group I PAK proteins in driving mutant Ras cancers. ©2014 American Association for Cancer Research.

  1. Gut-derived commensal bacterial products inhibit liver dendritic cell maturation by stimulating hepatic interleukin-6/signal transducer and activator of transcription 3 activity.

    PubMed

    Lunz, John G; Specht, Susan M; Murase, Noriko; Isse, Kumiko; Demetris, Anthony J

    2007-12-01

    Intraorgan dendritic cells (DCs) monitor the environment and help translate triggers of innate immunity into adaptive immune responses. Liver-based DCs are continually exposed, via gut-derived portal venous blood, to potential antigens and bacterial products that can trigger innate immunity. However, somehow the liver avoids a state of perpetual inflammation and protects central immune organs from overstimulation. In this study, we tested the hypothesis that hepatic interleukin-6 (IL-6)/signal transducer and activator of transcription 3 (STAT3) activity increases the activation/maturation threshold of hepatic DCs toward innate immune signals. The results show that the liver nuclear STAT3 activity is significantly higher than that of other organs and is IL-6-dependent. Hepatic DCs in normal IL-6 wild-type (IL-6(+/+)) mice are phenotypically and functionally less mature than DCs from IL-6-deficient (IL-6(-/-)) or STAT3-inhibited IL-6(+/+) mice, as determined by surface marker expression, proinflammatory cytokine secretion, and allogeneic T-cell stimulation. IL-6(+/+) liver DCs produce IL-6 in response to exposure to lipopolysaccharide (LPS) and cytidine phosphate guanosine oligonucleotides (CpG) but are resistant to maturation compared with IL-6(-/-) liver DCs. Conversely, exogenous IL-6 inhibits LPS-induced IL-6(-/-) liver DC maturation. IL-6/STAT3 signaling influences the liver DC expression of toll-like receptor 9 and IL-1 receptor associated kinase-M. The depletion of gut commensal bacteria in IL-6(+/+) mice with oral antibiotics decreased portal blood endotoxin levels, lowered the expression of IL-6 and phospho-STAT3, and significantly increased liver DC maturation. Gut-derived bacterial products, by stimulating hepatic IL-6/STAT3 signaling, inhibit hepatic DC activation/maturation and thereby elevate the threshold needed for translating triggers of innate immunity into adaptive immune responses. Manipulating gut bacteria may therefore be an effective strategy

  2. Partial Least Squares Regression Models for the Analysis of Kinase Signaling.

    PubMed

    Bourgeois, Danielle L; Kreeger, Pamela K

    2017-01-01

    Partial least squares regression (PLSR) is a data-driven modeling approach that can be used to analyze multivariate relationships between kinase networks and cellular decisions or patient outcomes. In PLSR, a linear model relating an X matrix of dependent variables and a Y matrix of independent variables is generated by extracting the factors with the strongest covariation. While the identified relationship is correlative, PLSR models can be used to generate quantitative predictions for new conditions or perturbations to the network, allowing for mechanisms to be identified. This chapter will provide a brief explanation of PLSR and provide an instructive example to demonstrate the use of PLSR to analyze kinase signaling.

  3. Kinase cogs go forward and reverse in the Wnt signaling machine.

    PubMed

    Dale, Trevor

    2006-01-01

    An important link between Wnt binding at the cell surface and nuclear -catenin-TCF-dependent transcription has been made with the identification of kinases that promote the association of the Wnt receptor and -catenin turnover complexes. Surprisingly, the enzymes implicated had previously been suggested to inhibit rather than promote Wnt signaling.

  4. Functions of Calcium-Dependent Protein Kinases in Plant Innate Immunity

    PubMed Central

    Gao, Xiquan; Cox, Kevin L.; He, Ping

    2014-01-01

    An increase of cytosolic Ca2+ is generated by diverse physiological stimuli and stresses, including pathogen attack. Plants have evolved two branches of the immune system to defend against pathogen infections. The primary innate immune response is triggered by the detection of evolutionarily conserved pathogen-associated molecular pattern (PAMP), which is called PAMP-triggered immunity (PTI). The second branch of plant innate immunity is triggered by the recognition of specific pathogen effector proteins and known as effector-triggered immunity (ETI). Calcium (Ca2+) signaling is essential in both plant PTI and ETI responses. Calcium-dependent protein kinases (CDPKs) have emerged as important Ca2+ sensor proteins in transducing differential Ca2+ signatures, triggered by PAMPs or effectors and activating complex downstream responses. CDPKs directly transmit calcium signals by calcium binding to the elongation factor (EF)-hand domain at the C-terminus and substrate phosphorylation by the catalytic kinase domain at the N-terminus. Emerging evidence suggests that specific and overlapping CDPKs phosphorylate distinct substrates in PTI and ETI to regulate diverse plant immune responses, including production of reactive oxygen species, transcriptional reprogramming of immune genes, and the hypersensitive response. PMID:27135498

  5. The Structural Basis for Activation and Inhibition of ZAP-70 Kinase Domain.

    PubMed

    Huber, Roland G; Fan, Hao; Bond, Peter J

    2015-10-01

    ZAP-70 (Zeta-chain-associated protein kinase 70) is a tyrosine kinase that interacts directly with the activated T-cell receptor to transduce downstream signals, and is hence a major player in the regulation of the adaptive immune response. Dysfunction of ZAP-70 causes selective T cell deficiency that in turn results in persistent infections. ZAP-70 is activated by a variety of signals including phosphorylation of the kinase domain (KD), and binding of its regulatory tandem Src homology 2 (SH2) domains to the T cell receptor. The present study investigates molecular mechanisms of activation and inhibition of ZAP-70 via atomically detailed molecular dynamics simulation approaches. We report microsecond timescale simulations of five distinct states of the ZAP-70 KD, comprising apo, inhibited and three phosphorylated variants. Extensive analysis of local flexibility and correlated motions reveal crucial transitions between the states, thus elucidating crucial steps in the activation mechanism of the ZAP-70 KD. Furthermore, we rationalize previously observed staurosporine-bound crystal structures, suggesting that whilst the KD superficially resembles an "active-like" conformation, the inhibitor modulates the underlying protein dynamics and restricts it in a compact, rigid state inaccessible to ligands or cofactors. Finally, our analysis reveals a novel, potentially druggable pocket in close proximity to the activation loop of the kinase, and we subsequently use its structure in fragment-based virtual screening to develop a pharmacophore model. The pocket is distinct from classical type I or type II kinase pockets, and its discovery offers promise in future design of specific kinase inhibitors, whilst mutations in residues associated with this pocket are implicated in immunodeficiency in humans.

  6. The Structural Basis for Activation and Inhibition of ZAP-70 Kinase Domain

    PubMed Central

    Huber, Roland G.; Fan, Hao; Bond, Peter J.

    2015-01-01

    ZAP–70 (Zeta-chain-associated protein kinase 70) is a tyrosine kinase that interacts directly with the activated T-cell receptor to transduce downstream signals, and is hence a major player in the regulation of the adaptive immune response. Dysfunction of ZAP–70 causes selective T cell deficiency that in turn results in persistent infections. ZAP–70 is activated by a variety of signals including phosphorylation of the kinase domain (KD), and binding of its regulatory tandem Src homology 2 (SH2) domains to the T cell receptor. The present study investigates molecular mechanisms of activation and inhibition of ZAP–70 via atomically detailed molecular dynamics simulation approaches. We report microsecond timescale simulations of five distinct states of the ZAP–70 KD, comprising apo, inhibited and three phosphorylated variants. Extensive analysis of local flexibility and correlated motions reveal crucial transitions between the states, thus elucidating crucial steps in the activation mechanism of the ZAP–70 KD. Furthermore, we rationalize previously observed staurosporine-bound crystal structures, suggesting that whilst the KD superficially resembles an “active-like” conformation, the inhibitor modulates the underlying protein dynamics and restricts it in a compact, rigid state inaccessible to ligands or cofactors. Finally, our analysis reveals a novel, potentially druggable pocket in close proximity to the activation loop of the kinase, and we subsequently use its structure in fragment-based virtual screening to develop a pharmacophore model. The pocket is distinct from classical type I or type II kinase pockets, and its discovery offers promise in future design of specific kinase inhibitors, whilst mutations in residues associated with this pocket are implicated in immunodeficiency in humans. PMID:26473606

  7. Targeting Janus tyrosine kinase 3 (JAK3) with an inhibitor induces secretion of TGF-β by CD4+ T cells

    PubMed Central

    Cetkovic-Cvrlje, Marina; Olson, Marin; Ghate, Ketaki

    2012-01-01

    Regulatory T cells (Tregs) are critical for the peripheral maintenance of the autoreactive T cells in autoimmune disorders such as type 1 diabetes (T1D). Pharmacological inhibition of Janus tyrosine kinase 3 (JAK3) has been proposed as a basis for new treatment modalities against autoimmunity and allogeneic responses. Targeting JAK3 with an inhibitor has previously been shown to exhibit protective action against the development of T1D in non-obese diabetic (NOD) mice. As the mechanism of such preventative action has been unknown, we hypothesized that JAK3 inhibition induces generation of Tregs. Here, we show that the JAK3 inhibitor 4-(4′-hydroxyphenyl)-amino-6,7-dimethoxyquinazoline (WHI-P131) suppresses proliferation of short-term cultured NOD CD4+ T cells through induction of apoptosis, while promoting survival of a particular population of long-term cultured cells. It was found that the surviving cells were not of the CD4+CD25+FoxP3+ phenotype. They secreted decreased amounts of IL-10, IL-4 and interferon (IFN)-γ compared to the cells not exposed to the optimal concentrations of JAK3 inhibitor. However, an elevated transforming growth factor (TGF)-β secretion was detected in their supernatants. In vivo treatment of prediabetic NOD mice with WHI-P131 did not affect the frequency and number of splenic and pancreatic lymph node CD4+FoxP3+ Tregs, while generating an elevated numbers of CD4+FoxP3− TGF-β-secreting T cells. In conclusion, our data suggest an induction of TGF-β-secreting CD4+ T cells as the underlying mechanism for antidiabetogenic effects obtained by the treatment with a JAK3 inhibitor. To our knowledge, this is the first report of the JAK3 inhibitor activity in the context of the murine Tregs. PMID:22728763

  8. The therapeutic effect of artesunate on rosacea through the inhibition of the JAK/STAT signaling pathway.

    PubMed

    Li, Ting; Zeng, Qingwen; Chen, Xingming; Wang, Guojiang; Zhang, Haiqing; Yu, Aihua; Wang, Hairui; Hu, Yang

    2018-06-01

    Acne rosacea is a type of chronic dermatosis with the characteristics of erubescence, angiotelectasis and pustule formation. However, current treatment methods are limited due to the side effects. Artesunate demonstrated a promising therapeutic efficacy with a high safety margin. HaCaT cells were treated with antibacterial peptide LL‑37 to simulate rosacea caused by Demodex folliculorum (D. folliculorum) infection. Cell Counting kit 8 and flow cytometry assays were performed to measure cellular proliferation, apoptosis, the stage of the cell cycle and reactive oxygen species generation in order to determine the level of cell damage. Then the damaged cells were treated with different concentrations of artesunate and doxycycline to determine the therapeutic effect of artesunate. Pro‑inflammatory cytokines tumor necrosis factor‑α (TNF‑α), interleukin (IL)‑6, IL‑8 and C‑C motif chemokine 2 (MCP‑1) were measured using an ELISA, while western blotting was used to detect the expression of Janus kinase 2 (JAK2) and signal transducer and transcription activator (STAT3). As a result, LL‑37 treated HaCaT cells decreased in cell viability, had an increased apoptotic rate and cell cycle arrest, indicating that cell damage caused by rosacea was simulated. In addition, upregulated concentrations of the pro‑inflammatory cytokines TNF‑α, IL‑6, IL‑8 and MCP‑1 were attenuated in the artesunate group in a dose‑dependent fashion, indicating the therapeutic effect of artesunate. Furthermore, higher concentrations of artesunate exhibited an improved effect compared with the doxycycline group. In addition, increased expression levels of JAK2 and STAT3 following treatment with LL‑37 suggested that rosacea caused by D. folliculorum infection may lead to inflammation through the JAK/STAT signaling pathway. In conclusion, the potential mechanism by which damage occurs in rosacea was revealed and a promising therapeutic method against rosacea was demonstrated.

  9. Electroformation of Janus and patchy capsules

    NASA Astrophysics Data System (ADS)

    Rozynek, Zbigniew; Mikkelsen, Alexander; Dommersnes, Paul; Fossum, Jon Otto

    2014-05-01

    Janus and patchy particles have designed heterogeneous surfaces that consist of two or several patches with different materials properties. These particles are emerging as building blocks for a new class of soft matter and functional materials. Here we introduce a route for forming heterogeneous capsules by producing highly ordered jammed colloidal shells of various shapes with domains of controlled size and composition. These structures combine the functionalities offered by Janus or patchy particles, and those given by permeable shells such as colloidosomes. The simple assembly route involves the synergetic action of electro-hydrodynamic flow and electro-coalescence. We demonstrate that the method is robust and straightforwardly extendable to production of multi-patchy capsules. This forms a starting point for producing patchy colloidosomes with domains of anisotropic chemical surface properties, permeability or mixed liquid-solid phase domains, which could be exploited to produce functional emulsions, light and hollow supra-colloidosome structures, or scaffolds.

  10. Enhanced stability of Janus nanoparticles by covalent cross-linking of surface ligands.

    PubMed

    Song, Yang; Klivansky, Liana M; Liu, Yi; Chen, Shaowei

    2011-12-06

    A mercapto derivative of diacetylene was used as the hydrophilic ligand to prepare Janus nanoparticles by using hydrophobic hexanethiolate-protected gold (AuC6, diameter 5 nm) nanoparticles as the starting materials. The amphiphilic surface characters of the Janus nanoparticles were verified by contact angle measurements, as compared to those of the bulk-exchange counterparts where the two types of ligands were distributed rather homogeneously on the nanoparticle surface. Dynamic light scattering studies showed that the Janus nanoparticles formed stable superstructures in various solvent media that were significantly larger than those by the bulk-exchange counterparts. This was ascribed to the amphiphilic characters of the Janus nanoparticles that rendered the particles to behave analogously to conventional surfactant molecules. Notably, because of the close proximity of the diacetylene moieties on the Janus nanoparticle surface, exposure to UV irradiation led to effective covalent cross-linking between the diacetylene moieties of neighboring ligands, as manifested in UV-vis and fluorescence measurements where the emission characteristics of dimers and trimers of diacetylene were rather well-defined, in addition to the monomeric emission. In contrast, for bulk-exchange nanoparticles, no trimer emission could be identified, and the intensity of dimer emission was markedly lower (though the intensity increased with increasing diacetylene coverage on the particle surface) under the otherwise identical experimental conditions. This is largely because the diacetylene ligands were distributed on the entire particle surface, and it was difficult to find a large number of ligands situated closely so that the stringent topochemical principles for the polymerization of diacetylene derivatives could be met. Importantly, the cross-linked Janus nanoparticles were found to exhibit marked enhancement of the structural integrity, which was attributable to the impeded surface

  11. Comparison between Field Effect Transistors and Bipolar Junction Transistors as Transducers in Electrochemical Sensors

    NASA Astrophysics Data System (ADS)

    Zafar, Sufi; Lu, Minhua; Jagtiani, Ashish

    2017-01-01

    Field effect transistors (FET) have been widely used as transducers in electrochemical sensors for over 40 years. In this report, a FET transducer is compared with the recently proposed bipolar junction transistor (BJT) transducer. Measurements are performed on two chloride electrochemical sensors that are identical in all details except for the transducer device type. Comparative measurements show that the transducer choice significantly impacts the electrochemical sensor characteristics. Signal to noise ratio is 20 to 2 times greater for the BJT sensor. Sensitivity is also enhanced: BJT sensing signal changes by 10 times per pCl, whereas the FET signal changes by 8 or less times. Also, sensor calibration curves are impacted by the transducer choice. Unlike a FET sensor, the calibration curve of the BJT sensor is independent of applied voltages. Hence, a BJT sensor can make quantitative sensing measurements with minimal calibration requirements, an important characteristic for mobile sensing applications. As a demonstration for mobile applications, these BJT sensors are further investigated by measuring chloride levels in artificial human sweat for potential cystic fibrosis diagnostic use. In summary, the BJT device is demonstrated to be a superior transducer in comparison to a FET in an electrochemical sensor.

  12. GIT1/βPIX signaling proteins and PAK1 kinase regulate microtubule nucleation.

    PubMed

    Černohorská, Markéta; Sulimenko, Vadym; Hájková, Zuzana; Sulimenko, Tetyana; Sládková, Vladimíra; Vinopal, Stanislav; Dráberová, Eduarda; Dráber, Pavel

    2016-06-01

    Microtubule nucleation from γ-tubulin complexes, located at the centrosome, is an essential step in the formation of the microtubule cytoskeleton. However, the signaling mechanisms that regulate microtubule nucleation in interphase cells are largely unknown. In this study, we report that γ-tubulin is in complexes containing G protein-coupled receptor kinase-interacting protein 1 (GIT1), p21-activated kinase interacting exchange factor (βPIX), and p21 protein (Cdc42/Rac)-activated kinase 1 (PAK1) in various cell lines. Immunofluorescence microscopy revealed association of GIT1, βPIX and activated PAK1 with centrosomes. Microtubule regrowth experiments showed that depletion of βPIX stimulated microtubule nucleation, while depletion of GIT1 or PAK1 resulted in decreased nucleation in the interphase cells. These data were confirmed for GIT1 and βPIX by phenotypic rescue experiments, and counting of new microtubules emanating from centrosomes during the microtubule regrowth. The importance of PAK1 for microtubule nucleation was corroborated by the inhibition of its kinase activity with IPA-3 inhibitor. GIT1 with PAK1 thus represent positive regulators, and βPIX is a negative regulator of microtubule nucleation from the interphase centrosomes. The regulatory roles of GIT1, βPIX and PAK1 in microtubule nucleation correlated with recruitment of γ-tubulin to the centrosome. Furthermore, in vitro kinase assays showed that GIT1 and βPIX, but not γ-tubulin, serve as substrates for PAK1. Finally, direct interaction of γ-tubulin with the C-terminal domain of βPIX and the N-terminal domain of GIT1, which targets this protein to the centrosome, was determined by pull-down experiments. We propose that GIT1/βPIX signaling proteins with PAK1 kinase represent a novel regulatory mechanism of microtubule nucleation in interphase cells. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. BDNF — a key transducer of antidepressant effects

    PubMed Central

    Björkholm, Carl; Monteggia, Lisa M.

    2016-01-01

    How do antidepressants elicit an antidepressant response? Here, we review accumulating evidence that the neurotrophin brain-derived neurotrophic factor (BDNF) serves as a transducer, acting as the link between the antidepressant drug and the neuroplastic changes that result in the improvement of the depressive symptoms. Over the last decade several studies have consistently highlighted BDNF as a key player in antidepressant action. An increase in hippocampal and cortical expression of BDNF mRNA parallels the antidepressant-like response of conventional antidepressants such as SSRIs. Subsequent studies showed that a single bilateral infusion of BDNF into the ventricles or directly into the hippocampus is sufficient to induce a relatively rapid and sustained antidepressant-like effect. Importantly, the antidepressant-like response to conventional antidepressants is attenuated in mice where the BDNF signaling has been disrupted by genetic manipulations. Low dose ketamine, which has been found to induce a rapid antidepressant effect in patients with treatment-resistant depression, is also dependent on increased BDNF signaling. Ketamine transiently increases BDNF translation in hippocampus, leading to enhanced synaptic plasticity and synaptic strength. Ketamine has been shown to increase BDNF translation by blocking NMDA receptor activity at rest, thereby inhibiting calcium influx and subsequently halting eukaryotic elongation factor 2 (eEF2) kinase leading to a desuppression of protein translation, including BDNF translation. The antidepressant-like response of ketamine is abolished in BDNF and TrkB conditional knockout mice, eEF2 kinase knockout mice, in mice carrying the BDNF met/met allele, and by intra-cortical infusions of BDNF-neutralizing antibodies. In summary, current data suggests that conventional antidepressants and ketamine mediate their antidepressant-like effects by increasing BDNF in forebrain regions, in particular the hippocampus, making BDNF an

  14. p53 is a major component of the transcriptional and apoptotic program regulated by PI 3-kinase/Akt/GSK3 signaling.

    PubMed

    Nayak, G; Cooper, G M

    2012-10-11

    The phosphatidylinositol (PI) 3-kinase/Akt signaling pathway has a prominent role in cell survival and proliferation, in part, by regulating gene expression at the transcriptional level. Previous work using global expression profiling identified FOXOs and the E-box-binding transcription factors MITF and USF1 as key targets of PI 3-kinase signaling that lead to the induction of proapoptotic and cell cycle arrest genes in response to inhibition of PI 3-kinase. In this study, we investigated the role of p53 downstream of PI 3-kinase signaling by analyzing the effects of inhibition of PI 3-kinase in Rat-1 cells, which have wild-type p53, compared with Rat-1 cells expressing a dominant-negative p53 mutant. Expression of dominant-negative p53 conferred partial resistance to apoptosis induced by inhibition of PI 3-kinase. Global gene expression profiling combined with computational and experimental analysis of transcription factor binding sites demonstrated that p53, along with FOXO, MITF and USF1, contributed to gene induction in response to PI 3-kinase inhibition. Activation of p53 was mediated by phosphorylation of the histone acetyltransferase Tip60 by glycogen synthase kinase (GSK) 3, leading to activation of p53 by acetylation. Many of the genes targeted by p53 were also targeted by FOXO and E-box-binding transcription factors, indicating that p53 functions coordinately with these factors to regulate gene expression downstream of PI 3-kinase/Akt/GSK3 signaling.

  15. Enhancing Endosomal Escape of Transduced Proteins by Photochemical Internalisation

    PubMed Central

    Mellert, Kevin; Lamla, Markus; Scheffzek, Klaus; Wittig, Rainer; Kaufmann, Dieter

    2012-01-01

    Induced internalisation of functional proteins into cultured cells has become an important aspect in a rising number of in vitro and in vivo assays. The endo-lysosomal entrapment of the transduced proteins remains the major problem in all transduction protocols. In this study we compared the efficiency, cytotoxicity and protein targeting of different commercially available transduction reagents by transducing a well-studied fluorescently labelled protein (Atto488-bovine serum albumin) into cultured human sarcoma cells. The amount of internalised protein and toxicity differed between the different reagents, but the percentage of transduced cells was consistently high. Furthermore, in all protocols the signals of the transduced Atto488-BSA were predominantly punctual consistent with an endosomal localisation. To overcome the endosomal entrapment, the transduction protocols were combined with a photochemical internalisation (PCI) treatment. Using this combination revealed that an endosomal disruption is highly effective in cell penetrating peptide (CPP) mediated transduction, whereas lipid-mediated transductions lead to a lower signal spreading throughout the cytosol. No change in the signal distribution could be achieved in treatments using non-lipid polymers as a transduction reagent. Therefore, the combination of protein transduction protocols based on CPPs with the endosomolytic treatment PCI can facilitate protein transduction experiments in vitro. PMID:23285056

  16. Enhancing endosomal escape of transduced proteins by photochemical internalisation.

    PubMed

    Mellert, Kevin; Lamla, Markus; Scheffzek, Klaus; Wittig, Rainer; Kaufmann, Dieter

    2012-01-01

    Induced internalisation of functional proteins into cultured cells has become an important aspect in a rising number of in vitro and in vivo assays. The endo-lysosomal entrapment of the transduced proteins remains the major problem in all transduction protocols. In this study we compared the efficiency, cytotoxicity and protein targeting of different commercially available transduction reagents by transducing a well-studied fluorescently labelled protein (Atto488-bovine serum albumin) into cultured human sarcoma cells. The amount of internalised protein and toxicity differed between the different reagents, but the percentage of transduced cells was consistently high. Furthermore, in all protocols the signals of the transduced Atto488-BSA were predominantly punctual consistent with an endosomal localisation. To overcome the endosomal entrapment, the transduction protocols were combined with a photochemical internalisation (PCI) treatment. Using this combination revealed that an endosomal disruption is highly effective in cell penetrating peptide (CPP) mediated transduction, whereas lipid-mediated transductions lead to a lower signal spreading throughout the cytosol. No change in the signal distribution could be achieved in treatments using non-lipid polymers as a transduction reagent. Therefore, the combination of protein transduction protocols based on CPPs with the endosomolytic treatment PCI can facilitate protein transduction experiments in vitro.

  17. Intestinal immune responses of Jian carp against Aeromonas hydrophila depressed by choline deficiency: Varied change patterns of mRNA levels of cytokines, tight junction proteins and related signaling molecules among three intestinal segments.

    PubMed

    Wu, Pei; Liu, Yang; Jiang, Wei-Dan; Jiang, Jun; Zhang, Yong-An; Zhou, Xiao-Qiu; Feng, Lin

    2017-06-01

    This study aimed to investigate the effects of choline deficiency on intestinal inflammation of fish after Aeromonas hydrophila infection and the potential molecular mechanisms. Juvenile Jian carp (Cyprinus carpio var. Jian) were fed two diets containing choline at 165 (deficient group) and 607 mg/kg diet respectively for 65 days. Choline deficiency decreased intestinal lysozyme activity, C3 and IgM contents, increased acid phosphatase activity, downregulated mRNA levels of antimicrobial peptides [liver-expressed antimicrobial peptide (LEAP) 2A, LEAP-2B, hepcidin and defensin], cytokines [interleukin (IL) 6a, tumor necrosis factor α (TNF-α), interferon γ2b (IFN-γ2b), IL-6b and transforming growth factor β2 (TGF-β2) only in proximal intestine, IL-10 in mid and distal intestine], immune-related signaling molecules [Toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88), nuclear factor kappa B (NF-κB), inhibitor of NF-κB (IκB), Janus kinase 3 (JAK3), and signal transducers and activators of transcription 5 (STAT5)], tight junction proteins (claudin 3b, claudin 3c, claudin 11 and occludin), and mitogen-activated protein kinases p38 (p38 MAPK ) in proximal and distal intestine of juvenile Jian carp after A. hydrophila challenge. In contrast, choline deficiency upregulated mRNA levels of antimicrobial peptides (LEAP-2A, LEAP-2B, hepcidin and defensin), cytokines (IL-6b, IFN-γ2b and TGF-β2), immune-related signaling molecules (TLR4, MyD88, NF-κB, IκB, JAK3, STAT4 in three intestinal segments, and STAT6), claudin 11, and p38 MAPK in mid intestine of fish. This study provides new finding that choline deficiency-induced immune responses against A. hydrophila infection were varied among three intestinal segments in fish. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Focal Length Controllable Ultrasonic Transducer Using Bimorph-Type Bending Actuator

    NASA Astrophysics Data System (ADS)

    Chae, Min-Ku; Kim, Moo-Joon; Ha, Kang-Lyeol; Lee, Chai-Bong

    2003-05-01

    Using a bimorph-type bending actuator, we propose a new method for controlling the focal length of a transducer by electric DC voltage. We designed two focal length controllable ultrasonic transducers with actuators, a line-focus and a point-focus transducer. The polyvinylidene fluoride (PVDF) piezoelectric type polymer film is used for transmitting and receiving of ultrasonic signals. Using the new method, it is confirmed by investigation of the underwater acoustic field that the focal length can be controlled to within 10% of the radius of the transducer curvature.

  19. Lysophosphatidylcholine up-regulates human endothelial nitric oxide synthase gene transactivity by c-Jun N-terminal kinase signalling pathway

    PubMed Central

    Xing, Feiyue; Liu, Jing; Mo, Yongyan; Liu, Zhifeng; Qin, Qinghe; Wang, Jingzhen; Fan, Zhenhua; Long, Yutian; Liu, Na; Zhao, Kesen; Jiang, Yong

    2009-01-01

    Human endothelial nitric oxide synthase (eNOS) plays a pivotal role in maintaining blood pressure homeostasis and vascular integrity. It has recently been reported that mitogen-activated protein kinases (MAPKs) are intimately implicated in expression of eNOS. However detailed mechanism mediated by them remains to be clarified. In this study, eNOS gene transactivity in human umbilical vein endothelial cells was up-regulated by stimulation of lysophosphatidylcholine (LPC). The stimulation of LPC highly activated both extracellular signal-regulated kinase 1/2 (ERK1/2) and c-Jun N-terminal kinase (JNK), with differences in the dynamic processes of activation between them. Unexpectedly, p38 MAPK could not be activated by the stimulation of LPC. The activation of JNK signalling pathway by overexpression of JNK or its upstream kinase active mutant up-regulated the transactivity of eNOS significantly, but the activation of p38 signalling pathway down-regulated it largely. The inhibition of either ERK1/2 or JNK signalling pathway by kinase-selective inhibitors could markedly block the induction of the transactivity by LPC. It was observed by electrophoretic mobility shift assay that LPC stimulated both SP1 and AP1 DNA binding activity to go up. Additionally using decoy oligonucleotides proved that SP1 was necessary for maintaining the basal or stimulated transactivity, whereas AP1 contributed mainly to the increase of the stimulated transactivity. These findings indicate that the up-regulation of the eNOS gene transactivity by LPC involves the enhancement of SP1 transcription factor by the activation of JNK and ERK1/2 signalling pathways and AP1 transcription factor by the activation of JNK signalling pathway. PMID:18624763

  20. De Novo Characterization of the Spleen Transcriptome of the Large Yellow Croaker (Pseudosciaena crocea) and Analysis of the Immune Relevant Genes and Pathways Involved in the Antiviral Response

    PubMed Central

    Ding, Yang; Ao, Jingqun; Hu, Songnian; Chen, Xinhua

    2014-01-01

    The large yellow croaker (Pseudosciaena crocea) is an economically important marine fish in China. To understand the molecular basis for antiviral defense in this species, we used Illumia paired-end sequencing to characterize the spleen transcriptome of polyriboinosinic:polyribocytidylic acid [poly(I:C)]-induced large yellow croakers. The library produced 56,355,728 reads and assembled into 108,237 contigs. As a result, 15,192 unigenes were found from this transcriptome. Gene ontology analysis showed that 4,759 genes were involved in three major functional categories: biological process, cellular component, and molecular function. We further ascertained that numerous consensus sequences were homologous to known immune-relevant genes. Kyoto Encyclopedia of Genes and Genomes orthology mapping annotated 5,389 unigenes and identified numerous immune-relevant pathways. These immune-relevant genes and pathways revealed major antiviral immunity effectors, including but not limited to: pattern recognition receptors, adaptors and signal transducers, the interferons and interferon-stimulated genes, inflammatory cytokines and receptors, complement components, and B-cell and T-cell antigen activation molecules. Moreover, the partial genes of Toll-like receptor signaling pathway, RIG-I-like receptors signaling pathway, Janus kinase-Signal Transducer and Activator of Transcription (JAK-STAT) signaling pathway, and T-cell receptor (TCR) signaling pathway were found to be changed after poly(I:C) induction by real-time polymerase chain reaction (PCR) analysis, suggesting that these signaling pathways may be regulated by poly(I:C), a viral mimic. Overall, the antivirus-related genes and signaling pathways that were identified in response to poly(I:C) challenge provide valuable leads for further investigation of the antiviral defense mechanism in the large yellow croaker. PMID:24820969

  1. Urokinase–urokinase receptor interaction mediates an inhibitory signal for HIV-1 replication

    PubMed Central

    Alfano, Massimo; Sidenius, Nicolai; Panzeri, Barbara; Blasi, Francesco; Poli, Guido

    2002-01-01

    Elevated levels of soluble urokinase-type plasminogen activator (uPA) receptor, CD87/u-PAR, predict survival in individuals infected with HIV-1. Here, we report that pro-uPA (or uPA) inhibits HIV-1 expression in U937-derived chronically infected promonocytic U1 cells stimulated with phorbol 12-myristate 13-acetate (PMA) or tumor necrosis factor-α (TNF-α). However, pro-uPA did not inhibit PMA or TNF-α-dependent activation of nuclear factor-kB or activation protein-1 in U1 cells. Cell-associated HIV protein synthesis also was not decreased by pro-uPA, although the release of virion-associated reverse transcriptase activity was substantially inhibited, suggesting a functional analogy between pro-uPA and the antiviral effects of IFNs. Indeed, cell disruption reversed the inhibitory effect of pro-uPA on activated U1 cells, and ultrastructural analysis confirmed that virions were preferentially retained within cell vacuoles in pro-uPA treated cells. Neither expression of endogenous IFNs nor activation of the IFN-inducible Janus kinase/signal transducer and activator of transcription pathway were induced by pro-uPA. Pro-uPA also inhibited acute HIV replication in monocyte-derived macrophages and activated peripheral blood mononuclear cells, although with great inter-donor variability. However, pro-uPA inhibited HIV replication in acutely infected promonocytic U937 cells and in ex vivo cultures of lymphoid tissue infected in vitro. Because these effects occurred at concentrations substantially lower than those affecting thrombolysis, pro-uPA may represent a previously uncharacterized class of antiviral agents mimicking IFNs in their inhibitory effects on HIV expression and replication. PMID:12084931

  2. New and Unexpected Biological Functions for the Src-Homology 2 Domain-Containing Phosphatase SHP-2 in the Gastrointestinal Tract.

    PubMed

    Coulombe, Geneviève; Rivard, Nathalie

    2016-01-01

    SHP-2 is a tyrosine phosphatase expressed in most embryonic and adult tissues. SHP-2 regulates many cellular functions including growth, differentiation, migration, and survival. Genetic and biochemical evidence show that SHP-2 is required for rat sarcoma viral oncogene/extracellular signal-regulated kinases mitogen-activated protein kinase pathway activation by most tyrosine kinase receptors, as well as by G-protein-coupled and cytokine receptors. In addition, SHP-2 can regulate the Janus kinase/signal transducers and activators of transcription, nuclear factor-κB, phosphatidyl-inositol 3-kinase/Akt, RhoA, Hippo, and Wnt/β-catenin signaling pathways. Emerging evidence has shown that SHP-2 dysfunction represents a key factor in the pathogenesis of gastrointestinal diseases, in particular in chronic inflammation and cancer. Variations within the gene locus encoding SHP-2 have been associated with increased susceptibility to develop ulcerative colitis and gastric atrophy. Furthermore, mice with conditional deletion of SHP-2 in intestinal epithelial cells rapidly develop severe colitis. Similarly, hepatocyte-specific deletion of SHP-2 induces hepatic inflammation, resulting in regenerative hyperplasia and development of tumors in aged mice. However, the SHP-2 gene initially was suggested to be a proto-oncogene because activating mutations of this gene were found in pediatric leukemias and certain forms of liver and colon cancers. Moreover, SHP-2 expression is up-regulated in gastric and hepatocellular cancers. Notably, SHP-2 functions downstream of cytotoxin-associated antigen A (CagA), the major virulence factor of Helicobacter pylori , and is associated with increased risks of gastric cancer. Further compounding this complexity, most recent findings suggest that SHP-2 also coordinates carbohydrate, lipid, and bile acid synthesis in the liver and pancreas. This review aims to summarize current knowledge and recent data regarding the biological functions of SHP-2

  3. Comprehensive Logic Based Analyses of Toll-Like Receptor 4 Signal Transduction Pathway

    PubMed Central

    Padwal, Mahesh Kumar; Sarma, Uddipan; Saha, Bhaskar

    2014-01-01

    Among the 13 TLRs in the vertebrate systems, only TLR4 utilizes both Myeloid differentiation factor 88 (MyD88) and Toll/Interleukin-1 receptor (TIR)-domain-containing adapter interferon-β-inducing Factor (TRIF) adaptors to transduce signals triggering host-protective immune responses. Earlier studies on the pathway combined various experimental data in the form of one comprehensive map of TLR signaling. But in the absence of adequate kinetic parameters quantitative mathematical models that reveal emerging systems level properties and dynamic inter-regulation among the kinases/phosphatases of the TLR4 network are not yet available. So, here we used reaction stoichiometry-based and parameter independent logical modeling formalism to build the TLR4 signaling network model that captured the feedback regulations, interdependencies between signaling kinases and phosphatases and the outcome of simulated infections. The analyses of the TLR4 signaling network revealed 360 feedback loops, 157 negative and 203 positive; of which, 334 loops had the phosphatase PP1 as an essential component. The network elements' interdependency (positive or negative dependencies) in perturbation conditions such as the phosphatase knockout conditions revealed interdependencies between the dual-specific phosphatases MKP-1 and MKP-3 and the kinases in MAPK modules and the role of PP2A in the auto-regulation of Calmodulin kinase-II. Our simulations under the specific kinase or phosphatase gene-deficiency or inhibition conditions corroborated with several previously reported experimental data. The simulations to mimic Yersinia pestis and E. coli infections identified the key perturbation in the network and potential drug targets. Thus, our analyses of TLR4 signaling highlights the role of phosphatases as key regulatory factors in determining the global interdependencies among the network elements; uncovers novel signaling connections; identifies potential drug targets for infections. PMID:24699232

  4. Hydrophobic/Hydrophilic Cooperative Janus System for Enhancement of Fog Collection.

    PubMed

    Cao, Moyuan; Xiao, Jiasheng; Yu, Cunming; Li, Kan; Jiang, Lei

    2015-09-09

    Harvesting micro-droplets from fog is a promising method for solving global freshwater crisis. Different types of fog collectors have been extensively reported during the last decade. The improvement of fog collection can be attributed to the immediate transportation of harvested water, the effective regeneration of the fog gathering surface, etc. Through learning from the nature's strategy for water preservation, the hydrophobic/hydrophilic cooperative Janus system that achieved reinforced fog collection ability is reported here. Directional delivery of the surface water, decreased re-evaporation rate of the harvested water, and thinner boundary layer of the collecting surface contribute to the enhancement of collection efficiency. Further designed cylinder Janus collector can facilely achieve a continuous process of efficient collection, directional transportation, and spontaneous preservation of fog water. This Janus fog harvesting system should improve the understanding of micro-droplet collection system and offer ideas to solve water resource crisis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Spinal IL-33/ST2 Signaling Contributes to Neuropathic Pain via Neuronal CaMKII-CREB and Astroglial JAK2-STAT3 Cascades in Mice.

    PubMed

    Liu, Shenbin; Mi, Wen-Li; Li, Qian; Zhang, Meng-Ting; Han, Ping; Hu, Shan; Mao-Ying, Qi-Liang; Wang, Yan-Qing

    2015-11-01

    Emerging evidence indicates that nerve damage-initiated neuroinflammation and immune responses, which are evidenced by the up-regulation of proinflammatory cytokines, contribute to the development of neuropathic pain. This study investigated the role of spinal interleukin (IL)-33 and its receptor ST2 in spared nerve injury (SNI)-induced neuropathic pain. The von Frey test and acetone test were performed to evaluate neuropathic pain behaviors (n = 8 to 12), and Western blot (n = 4 to 6), immunohistochemistry, real-time polymerase chain reaction (n = 5), and Bio-Plex (n = 5) assays were performed to understand the molecular mechanisms. Intrathecal administration of ST2-neutralizing antibody or ST2 gene knockout (ST2) significantly attenuated the SNI-induced mechanical and cold allodynia. On the 7th day after SNI, the expression of spinal IL-33 and ST2 was increased by 255.8 ± 27.3% and 266.4 ± 83.5% (mean ± SD), respectively. Mechanistic studies showed that the increased expression of the spinal N-methyl-D-aspartate (NMDA) receptor subunit 1 after SNI was reduced by ST2 antibody administration or ST2. The induction of nociceptive behaviors in naive mice due to recombinant IL-33 was reversed by the noncompetitive NMDA antagonist MK-801. ST2 antibody administration or ST2 markedly inhibited the increased activation of the astroglial janus kinase 2 (JAK2)-signal transducer and activator of transcription 3 (STAT3) cascade and the neuronal calcium-calmodulin-dependent kinase II (CaMKII)-cyclic adenosine monophosphate response element-binding protein (CREB) cascade after SNI. Moreover, intrathecal pretreatment with the CaMKII inhibitor KN-93 or the JAK2-STAT3 cascade inhibitor AG490 attenuated recombinant IL-33-induced nociceptive behaviors and NMDA subunit 1 up-regulation in naive mice. Spinal IL-33/ST2 signaling contributes to neuropathic pain by activating the astroglial JAK2-STAT3 cascade and the neuronal CaMKII-CREB cascade.

  6. Mitogenic signals and transforming potential of Nyk, a newly identified neural cell adhesion molecule-related receptor tyrosine kinase.

    PubMed Central

    Ling, L; Kung, H J

    1995-01-01

    Nyk/Mer is a recently identified receptor tyrosine kinase with neural cell adhesion molecule-like structure (two immunoglobulin G-like domains and two fibronectin III-like domains) in its extracellular region and belongs to the Ufo/Axl family of receptors. The ligand for Nyk/Mer is presently unknown, as are the signal transduction pathways mediated by this receptor. We constructed and expressed a chimeric receptor (Fms-Nyk) composed of the extracellular domain of the human colony-stimulating factor 1 receptor (Fms) and the transmembrane and cytoplasmic domains of human Nyk/Mer in NIH 3T3 fibroblasts in order to investigate the mitogenic signaling and biochemical properties of Nyk/Mer. Colony-stimulating factor 1 stimulation of the Fms-Nyk chimeric receptor in transfected NIH 3T3 fibroblasts leads to a transformed phenotype and generates a proliferative response in the absence of other growth factors. We show that phospholipase C gamma, phosphatidylinositol 3-kinase/p70 S6 kinase, Shc, Grb2, Raf-1, and mitogen-activated protein kinase are downstream components of the Nyk/Mer signal transduction pathways. In addition, Nyk/Mer weakly activates p90rsk, while stress-activated protein kinase, Ras GTPase-activating protein (GAP), and GAP-associated p62 and p190 proteins are not activated or tyrosine phosphorylated by Nyk/Mer. An analysis comparing the Nyk/Mer signal cascade with that of the epidermal growth factor receptor indicates substrate preferences by these two receptors. Our results provide a detailed description of the Nyk/Mer signaling pathways. Given the structural similarity between the Ufo/Axl family receptors, some of the information may also be applied to other members of this receptor tyrosine kinase family. PMID:8524223

  7. α-Hederin inhibits interleukin 6-induced epithelial-to-mesenchymal transition associated with disruption of JAK2/STAT3 signaling in colon cancer cells.

    PubMed

    Sun, Dongdong; Shen, Weixing; Zhang, Feng; Fan, Huisen; Xu, Changliang; Li, Liu; Tan, Jiani; Miao, Yunjie; Zhang, Haibin; Yang, Ye; Cheng, Haibo

    2018-05-01

    Colon cancer is the third most frequently diagnosed malignancy and has high morbidity worldwide. Epithelial-mesenchymal transition (EMT) has been increasingly implicated in colon cancer progression and metastasis. The present study was aimed to evaluate the potential antitumor activity of α-hederin, a monodesmosidic triterpenoid saponin isolated from Hedera helix, in human SW620 colon cancer cells stimulated with interleukin 6 (IL-6) for mimicking the tumor inflammatory microenvironment in vivo. Cell viability assay showed that IL-6 at 6.25 ng/ml significantly enhanced viability of SW620 cells, and thus this concentration was used to stimulate SW620 cells throughout this study. We observed that α-hederin concentration-dependently inhibited cell viability, migration and invasion in IL-6-treated SW620 cells. Moreover, α-hederin significantly restored IL-6-induced decrease in E-cadherin expression and abolished IL-6-induced increase in N-cadherin, vimentin, fibronectin, twist and snail at both mRNA and protein levels in SW620 cells. These data suggested that α-hederin suppressed IL-6-indcued EMT in colon cancer cells. Further molecular examinations showed that α-hederin inhibited phosphorylation of Janus Kinase 2 (JAK2) and Signal Transducer and Activator of Transcription 3(STAT3), and halted the nuclear translocation of phosphorylated STAT3 in IL-6-treated SW620 cells. In addition, JAK2/STAT3 signaling inhibitor AG490 not only produced similar inhibitory effects on EMT markers as α-hederin, but also synergistically enhanced α-hederin's inhibitory effects on EMT markers in IL-6-treated SW620 cells. Altogether, we demonstrated that α-hederin suppressed IL-6-induced EMT associated with disruption of JAK2/STAT3 signaling in colon cancer cells. Our data strongly suggested α-hederin as a promising candidate for intervention of colon cancer and metastasis. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  8. Caveolin-1 regulates shear stress-dependent activation of extracellular signal-regulated kinase

    NASA Technical Reports Server (NTRS)

    Park, H.; Go, Y. M.; Darji, R.; Choi, J. W.; Lisanti, M. P.; Maland, M. C.; Jo, H.

    2000-01-01

    Fluid shear stress activates a member of the mitogen-activated protein (MAP) kinase family, extracellular signal-regulated kinase (ERK), by mechanisms dependent on cholesterol in the plasma membrane in bovine aortic endothelial cells (BAEC). Caveolae are microdomains of the plasma membrane that are enriched with cholesterol, caveolin, and signaling molecules. We hypothesized that caveolin-1 regulates shear activation of ERK. Because caveolin-1 is not exposed to the outside, cells were minimally permeabilized by Triton X-100 (0.01%) to deliver a neutralizing, polyclonal caveolin-1 antibody (pCav-1) inside the cells. pCav-1 then bound to caveolin-1 and inhibited shear activation of ERK but not c-Jun NH(2)-terminal kinase. Epitope mapping studies showed that pCav-1 binds to caveolin-1 at two regions (residues 1-21 and 61-101). When the recombinant proteins containing the epitopes fused to glutathione-S-transferase (GST-Cav(1-21) or GST-Cav(61-101)) were preincubated with pCav-1, only GST-Cav(61-101) reversed the inhibitory effect of the antibody on shear activation of ERK. Other antibodies, including m2234, which binds to caveolin-1 residues 1-21, had no effect on shear activation of ERK. Caveolin-1 residues 61-101 contain the scaffolding and oligomerization domains, suggesting that binding of pCav-1 to these regions likely disrupts the clustering of caveolin-1 or its interaction with signaling molecules involved in the shear-sensitive ERK pathway. We suggest that caveolae-like domains play a critical role in the mechanosensing and/or mechanosignal transduction of the ERK pathway.

  9. Coexpression of an unusual form of the EWS-WT1 fusion transcript and interleukin 2/15 receptor betamRNA in a desmoplastic small round cell tumour.

    PubMed

    Nakanishi, Y; Oinuma, T; Sano, M; Fuchinoue, F; Komatsu, K; Seki, T; Obana, Y; Tabata, M; Kikuchi, K; Shimamura, M; Ohmori, K; Nemoto, N

    2006-10-01

    The beta chain of the interleukin 2/15 receptor (IL-2/15Rbeta) is induced by the expression of the EWS-WT1. A case of desmoplastic small round cell tumour (DSRCT) expressing only an unusual EWS-WT1 treated by us is reported here. To characterise an unusual form of EWS-WT1. Frozen tissue sections of the axillary tumour were examined using a laser-assisted microdissection technique and reverse transcriptase polymerase chain reaction. The novel fusion of exon 8 of EWS and the defective exon 10 of WT1 (-KTS) was detected. Although it was an unusual form, the coexpression of the present EWS-WT1, IL-2/15Rbeta and Janus kinase (JAK1) mRNA was detected in the tumour cells. IL-2 and signal transducers and activators of transcription (STAT5) mRNA were detected in both tumour and stromal cells. The induction of the IL-2/15 receptor signalling pathway may contribute to tumorigenesis in DSRCT through a paracrine or an autocrine system, even though the EWS-WT1 was an unusual form.

  10. Fundamentals of heat measurement. [heat flux transducers

    NASA Technical Reports Server (NTRS)

    Gerashchenko, O. A.

    1979-01-01

    Various methods and devices for obtaining experimental data on heat flux density over wide ranges of temperature and pressure are examined. Laboratory tests and device fabrication details are supplemented by theoretical analyses of heat-conduction and thermoelectric effects, providing design guidelines and information relevant to further research and development. A theory defining the measure of correspondence between transducer signal and the measured heat flux is established for individual (isolated) heat flux transducers subject to space and time-dependent loading. An analysis of the properties of stacked (series-connected) transducers of various types (sandwich-type, plane, and spiral) is used to derive a similarity theory providing general governing relationships. The transducers examined are used in 36 types of derivative devices involving direct heat loss measurements, heat conduction studies, radiation pyrometry, calorimetry in medicine and industry and nuclear reactor dosimetry.

  11. A simple predistortion technique for suppression of nonlinear effects in periodic signals generated by nonlinear transducers

    NASA Astrophysics Data System (ADS)

    Novak, A.; Simon, L.; Lotton, P.

    2018-04-01

    Mechanical transducers, such as shakers, loudspeakers and compression drivers that are used as excitation devices to excite acoustical or mechanical nonlinear systems under test are imperfect. Due to their nonlinear behaviour, unwanted contributions appear at their output besides the wanted part of the signal. Since these devices are used to study nonlinear systems, it should be required to measure properly the systems under test by overcoming the influence of the nonlinear excitation device. In this paper, a simple method that corrects distorted output signal of the excitation device by means of predistortion of its input signal is presented. A periodic signal is applied to the input of the excitation device and, from analysing the output signal of the device, the input signal is modified in such a way that the undesirable spectral components in the output of the excitation device are cancelled out after few iterations of real-time processing. The experimental results provided on an electrodynamic shaker show that the spectral purity of the generated acceleration output approaches 100 dB after few iterations (1 s). This output signal, applied to the system under test, is thus cleaned from the undesirable components produced by the excitation device; this is an important condition to ensure a correct measurement of the nonlinear system under test.

  12. Pipe wall damage detection by electromagnetic acoustic transducer generated guided waves in absence of defect signals.

    PubMed

    Vasiljevic, Milos; Kundu, Tribikram; Grill, Wolfgang; Twerdowski, Evgeny

    2008-05-01

    Most investigators emphasize the importance of detecting the reflected signal from the defect to determine if the pipe wall has any damage and to predict the damage location. However, often the small signal from the defect is hidden behind the other arriving wave modes and signal noise. To overcome the difficulties associated with the identification of the small defect signal in the time history plots, in this paper the time history is analyzed well after the arrival of the first defect signal, and after different wave modes have propagated multiple times through the pipe. It is shown that the defective pipe can be clearly identified by analyzing these late arriving diffuse ultrasonic signals. Multiple reflections and scattering of the propagating wave modes by the defect and pipe ends do not hamper the defect detection capability; on the contrary, it apparently stabilizes the signal and makes it easier to distinguish the defective pipe from the defect-free pipe. This paper also highlights difficulties associated with the interpretation of the recorded time histories due to mode conversion by the defect. The design of electro-magnetic acoustic transducers used to generate and receive the guided waves in the pipe is briefly described in the paper.

  13. Biological responses to PDGF-BB versus PDGF-DD in human mesangial cells.

    PubMed

    van Roeyen, C R C; Ostendorf, T; Denecke, B; Bokemeyer, D; Behrmann, I; Strutz, F; Lichenstein, H S; LaRochelle, W J; Pena, C E; Chaudhuri, A; Floege, J

    2006-04-01

    Platelet-derived growth factor (PDGF)-BB and PDGF-DD mediate mesangial cell proliferation in vitro and in vivo. While PDGF-BB is a ligand for the PDGF alpha- and beta-receptor chains, PDGF-DD binds more selectively to the beta-chain, suggesting potential differences in the biological activities. Signal transduction and regulation of gene expression induced by PDGF-BB and -DD were compared in primary human mesangial cells (HMCs), which expressed PDGF alpha- and beta-receptor subunits. The growth factor concentrations used were chosen based on their equipotency in inducing HMCs proliferation and binding to the betabeta-receptor. Both growth factors, albeit at different concentrations induced phosphorylation and activation of extracellular signal-regulated kinase 1 (ERK1) and ERK2. In addition, PDGFs led to the phosphorylation and activation of signal transducers and activators of transcription 1 (STAT1) and STAT3. HMCs proliferation induced by either PDGF-BB or -DD could be blocked by signal transduction inhibitors of the mitogen-activated protein kinase-, Janus kinase (JAK)/STAT-, or phosphatidyl-inositol 3-kinase pathways. Using a gene chip array and subsequent verification by real-time reverse transcriptase (RT)-polymerase chain reaction, we found that in HMC genes for matrix metalloproteinase 13 (MMP-13) and MMP-14 and, to a low extent, cytochrome B5 and cathepsin L were exclusively regulated by PDGF-BB, whereas no exclusive gene regulation was detected by PDGF-DD. However, at the protein level, both MMP-13 and -14 were equally induced by PDGF-BB and -DD. PDGF-BB and -DD effect similar biological responses in HMCs albeit at different potencies. Rare apparently differential gene regulation did not result in different protein expression, suggesting that in HMCs both PDGFs exert their biological activity almost exclusively via the PDGF beta-receptor.

  14. Combined use of leptin and mechanical stress has osteogenic effects on ossification of the posterior longitudinal ligament.

    PubMed

    Chen, Shuai; Zhu, Haifeng; Wang, Gangliang; Xie, Ziang; Wang, Jiying; Chen, Jian

    2018-06-16

    To evaluate the effects of leptin/leptin receptor (LepR) combined with mechanical stress on the development of ossification of the posterior longitudinal ligament (OPLL), which is a disease characterized by ectopic bone formation of the posterior longitudinal ligament (PLL) and can lead to radiculopathy and myelopathy. Six human samples of the PLL were analyzed for the expression of leptin and LepR by RT-PCR and western blotting. PLL cells were stimulated with leptin and mechanical stress delivered via a Flexcell tension system, and osteogenic differentiation was evaluated by RT-PCR and western blotting analysis of osteogenic marker expression as well as by alkaline phosphatase (ALP) staining and alizarin red S staining. Activation of mitogen-activated protein kinase (MAPK), Janus kinase (JAK) 2-signal transducer, activator of transcription (STAT) 3 and phosphatidylinositol 3-kinase (PI3K)-Akt was evaluated by western blotting. Samples from the OPLL group had higher LepR mRNA and protein levels and lower leptin levels than those from healthy controls. Exposure to leptin and Flexcell increased the number of ALP-positive cells and calcium nodules in a dose-dependent manner; this effect was accompanied by upregulation of the osteogenic markers osteocalcin, runt-related transcription factor 2 (RUNX2) and osteopontin. Extracellular signal-regulated kinase, P38 MAPK, JAK2, STAT3, PI3K and Akt signaling, was also activated by the combined effects of leptin and mechanical stress. Leptin and LepR are differentially expressed in OPLL tissues, and the combined use of leptin/LepR and mechanical stress promotes osteogenic differentiation of PLL cells via MAPK, JAK2-STAT3 and PI3K/Akt signaling. These slides can be retrieved under Electronic Supplementary Material.

  15. Kurarinol induces hepatocellular carcinoma cell apoptosis through suppressing cellular signal transducer and activator of transcription 3 signaling

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shu, Guangwen; Yang, Jing; Zhao, Wenhao

    Kurarinol is a flavonoid isolated from roots of the medical plant Sophora flavescens. However, its cytotoxic activity against hepatocellular carcinoma (HCC) cells and toxic effects on mammalians remain largely unexplored. Here, the pro-apoptotic activities of kurarinol on HCC cells and its toxic impacts on tumor-bearing mice were evaluated. The molecular mechanisms underlying kurarinol-induced HCC cell apoptosis were also investigated. We found that kurarinol dose-dependently provoked HepG2, Huh-7 and H22 HCC cell apoptosis. In addition, kurarinol gave rise to a considerable decrease in the transcriptional activity of signal transducer and activator of transcription 3 (STAT3) in HCC cells. Suppression of STAT3more » signaling is involved in kurarinol-induced HCC cell apoptosis. In vivo studies showed that kurarinol injection substantially induced transplanted H22 cell apoptosis with low toxic impacts on tumor-bearing mice. Similarly, the transcriptional activity of STAT3 in transplanted tumor tissues was significantly suppressed after kurarinol treatment. Collectively, our current research demonstrated that kurarinol has the capacity of inducing HCC cell apoptosis both in vitro and in vivo with undetectable toxic impacts on the host. Suppressing STAT3 signaling is implicated in kurarinol-mediated HCC cell apoptosis. - Highlights: • Kurarinol induces hepatocellular carcinoma (HCC) cell apoptosis. • Kurarinol induces HCC cell apoptosis via inhibiting STAT3. • Kurarinol exhibits low toxic effects on tumor-bearing animals.« less

  16. Oryza sativa (Rice) Hull Extract Inhibits Lipopolysaccharide-Induced Inflammatory Response in RAW264.7 Macrophages by Suppressing Extracellular Signal-regulated Kinase, c-Jun N-terminal Kinase, and Nuclear Factor-κB Activation.

    PubMed

    Ha, Sang Keun; Sung, Jeehye; Choi, Inwook; Kim, Yoonsook

    2016-01-01

    Rice ( Oryza sativa ) is a major cereal crop in many Asian countries and an important staple food source. Rice hulls have been reported to possess antioxidant activities. In this study, we evaluated the antiinflammatory effects of rice hull extract and associated signal transduction mechanisms in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. We found that rice hull extract inhibited nitric oxide (NO) and prostaglandin E 2 by suppressing the expression of inducible NO synthase and cyclooxygenase-2, respectively. The release of interleukin-1β and tumor necrosis factor-α was also reduced in a dose-dependent manner. Furthermore, rice hull extract attenuated the activation of nuclear factor-kappa B (NF-κB), as well as the phosphorylation of mitogen-activated protein kinases, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK), in LPS-stimulated RAW264.7 cells. This suggests that rice hull extract decreases the production of inflammatory mediators by downregulating ERK and JNK and the NF-κB signal pathway in RAW 264.7 cells. Rice hull extract inhibits the lipopolysaccharide-induced inflammatory response in RAW264.7 macrophages.Rice hull extract inhibited nitric oxide and prostaglandin E 2 by suppressing the expression of inducible NO synthase and cyclooxygenase-2, respectively.Rice hull extract exerted anti-inflammatory effect through inhibition of nuclear factor-kappa B, extracellular signal-regulated kinase and c-Jun N-terminal kinase signaling pathways.Rice hull extract may provide a potential therapeutic approach for inflammatory diseases. Abbreviations used: COX-2: cyclooxygenase-2, ERK: extracellular signal-regulated kinase, IκB: inhibitory kappa B, IL-1β: interleukin-1β, iNOS: inducible NO synthase, JNK: c-Jun N-terminal kinase, LPS: lipopolysaccharide, MAPKs: mitogen-activated protein kinases, NF-κB: nuclear factor-κB, NO: nitric oxide, PGE2: prostaglandin E2, RHE: rice hull extract, ROS: reactive oxygen species

  17. Mannheimia haemolytica leukotoxin activates a nonreceptor tyrosine kinase signaling cascade in bovine leukocytes, which induces biological effects.

    PubMed

    Jeyaseelan, S; Kannan, M S; Briggs, R E; Thumbikat, P; Maheswaran, S K

    2001-10-01

    The leukotoxin (LktA) produced by Mannheimia haemolytica binds to bovine lymphocyte function-associated antigen 1 (LFA-1) and induces biological effects in bovine leukocytes in a cellular and species-specific fashion. We have previously shown that LktA also binds to porcine LFA-1 without eliciting any effects. These findings suggest that the specificity of LktA effects must entail both binding to LFA-1 and activation of signaling pathways which are present in bovine leukocytes. However, the signaling pathways leading to biological effects upon LktA binding to LFA-1 have not been characterized. In this context, several reports have indicated that ligand binding to LFA-1 results in activation of a nonreceptor tyrosine kinase (NRTK) signaling cascade. We designed experiments with the following objectives: (i) to determine whether LktA binding to LFA-1 leads to activation of NRTKs, (ii) to examine whether LktA-induced NRTK activation is target cell specific, and (iii) to determine whether LktA-induced NRTK activation is required for biological effects. We used a biologically inactive mutant leukotoxin (DeltaLktA) for comparison with LktA. Our results indicate that LktA induces tyrosine phosphorylation (TP) of the CD18 tail of LFA-1 in bovine leukocytes. The DeltaLktA mutant does not induce TP of the CD18 tail, albeit binding to bovine LFA-1. LktA-induced TP of the CD18 tail was attenuated by an NRTK inhibitor, herbimycin A; a phosphatidylinositol 3'-kinase (PI 3-kinase) inhibitor, wortmannin; and a Src kinase inhibitor, PP2, in a concentration-dependent manner. Furthermore, LktA induces TP of the CD18 tail in bovine, but not porcine, leukocytes. Moreover, LktA-induced intracellular calcium ([Ca2+]i) elevation was also inhibited by herbimycin A, wortmannin, and PP2. Thus, our data represent the first evidence that binding of LktA to bovine LFA-1 induces a species-specific NRTK signaling cascade involving PI 3-kinase and Src kinases and that this signaling cascade is

  18. Functional profiling of receptor tyrosine kinases and downstream signaling in human chondrosarcomas identifies pathways for rational targeted therapy.

    PubMed

    Zhang, Yi-Xiang; van Oosterwijk, Jolieke G; Sicinska, Ewa; Moss, Samuel; Remillard, Stephen P; van Wezel, Tom; Bühnemann, Claudia; Hassan, Andrew B; Demetri, George D; Bovée, Judith V M G; Wagner, Andrew J

    2013-07-15

    Chondrosarcomas are notoriously resistant to cytotoxic chemotherapeutic agents. We sought to identify critical signaling pathways that contribute to their survival and proliferation, and which may provide potential targets for rational therapeutic interventions. Activation of receptor tyrosine kinases (RTK) was surveyed using phospho-RTK arrays. S6 phosphorylation and NRAS mutational status were examined in chondrosarcoma primary tumor tissues. siRNA or small-molecule inhibitors against RTKs or downstream signaling proteins were applied to chondrosarcoma cells and changes in biochemical signaling, cell cycle, and cell viability were determined. In vivo antitumor activity of BEZ235, a phosphoinositide 3-kinase (PI3K)/mTOR inhibitor, was evaluated in a chondrosarcoma xenograft model. Several RTKs were identified as critical mediators of cell growth, but the RTK dependencies varied among cell lines. In exploration of downstream signaling pathways, strong S6 phosphorylation was found in 69% of conventional chondrosarcomas and 44% of dedifferentiated chondrosarcomas. Treatment with BEZ235 resulted in dramatic reduction in the growth of all chondrosarcoma cell lines. Tumor growth was similarly inhibited in a xenograft model of chondrosarcoma. In addition, chondrosarcoma cells with an NRAS mutation were sensitive to treatment with a mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK) inhibitor. Functional NRAS mutations were found in 12% of conventional central chondrosarcomas. RTKs are commonly activated in chondrosarcoma, but because of their considerable heterogeneity, targeted inhibition of the PI3K/mTOR pathway represents a rational therapeutic strategy. Chondrosarcomas with NRAS mutations may benefit from treatment with MEK inhibitors.

  19. Angiotensin II initiates tyrosine kinase Pyk2-dependent signalings leading to activation of Rac1-mediated c-Jun NH2-terminal kinase.

    PubMed

    Murasawa, S; Matsubara, H; Mori, Y; Masaki, H; Tsutsumi, Y; Shibasaki, Y; Kitabayashi, I; Tanaka, Y; Fujiyama, S; Koyama, Y; Fujiyama, A; Iba, S; Iwasaka, T

    2000-09-01

    Ca(2+)-sensitive tyrosine kinase Pyk2 was shown to be involved in angiotensin (Ang) II-mediated activation of extracellular signal-regulated kinase (ERK) via transactivation of epidermal growth factor receptor (EGF-R). In this study, we tested the involvement of Pyk2 and EGF-R in Ang II-induced activation of JNK and c-Jun in cardiac fibroblasts. Ang II markedly stimulated JNK activities, which were abolished by genistein and intracellular Ca(2+) chelators but partially by protein kinase C depletion. Inhibition of EGF-R did not affect Pyk2 and JNK activation by Ang II. Stable transfection with a dominant negative (DN) mutant for Pyk2 (PKM) completely blocked JNK activation by Ang II. DN mutants of Rac1 (DN-Rac1) and MEK kinase (DN-MEKK1) also abolished it, whereas those of Cdc42, RhoA, and Ha-Ras had no effect. Induction of c-Jun gene transcription by Ang II was abolished in PKM, DN-Rac1, and DN-MEKK1, in which Ang II-induced binding of ATF2/c-Jun heterodimer to the activator protein-1 sequence at -190 played a key role. These results suggest that 1) in cardiac fibroblasts activation of JNK and c-Jun by Ang II is initiated by Pyk2-dependent signalings but not by downstream signals of EGF-R or Ras, 2) Rac1 but not Cdc42 is required for JNK activation by Ang II upstream of MEKK1, and 3) ATF-2/c-Jun binding to the activator protein-1 sequence at -190 plays a key role for induction of c-Jun gene by Ang II.

  20. Oleanolic Acid Alters Multiple Cell Signaling Pathways: Implication in Cancer Prevention and Therapy.

    PubMed

    Žiberna, Lovro; Šamec, Dunja; Mocan, Andrei; Nabavi, Seyed Fazel; Bishayee, Anupam; Farooqi, Ammad Ahmad; Sureda, Antoni; Nabavi, Seyed Mohammad

    2017-03-16

    Nowadays, much attention has been paid to diet and dietary supplements as a cost-effective therapeutic strategy for prevention and treatment of a myriad of chronic and degenerative diseases. Rapidly accumulating scientific evidence achieved through high-throughput technologies has greatly expanded the understanding about the multifaceted nature of cancer. Increasingly, it is being realized that deregulation of spatio-temporally controlled intracellular signaling cascades plays a contributory role in the onset and progression of cancer. Therefore, targeting regulators of oncogenic signaling cascades is essential to prevent and treat cancer. A plethora of preclinical and epidemiological evidences showed promising role of phytochemicals against several types of cancer. Oleanolic acid, a common pentacyclic triterpenoid, is mainly found in olive oil, as well as several plant species. It is a potent inhibitor of cellular inflammatory process and a well-known inducer of phase 2 xenobiotic biotransformation enzymes. Main molecular mechanisms underlying anticancer effects of oleanolic acid are mediated by caspases, 5' adenosine monophosphate-activated protein kinase, extracellular signal-regulated kinase 1/2, matrix metalloproteinases, pro-apoptotic Bax and bid, phosphatidylinositide 3-kinase/Akt1/mechanistic target of rapamycin, reactive oxygen species/apoptosis signal-regulating kinase 1/p38 mitogen-activated protein kinase, nuclear factor-κB, cluster of differentiation 1, CKD4, s6k, signal transducer and activator of transcription 3, as well as aforementioned signaling pathways . In this work, we critically review the scientific literature on the molecular targets of oleanolic acid implicated in the prevention and treatment of several types of cancer. We also discuss chemical aspects, natural sources, bioavailability, and safety of this bioactive phytochemical.