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Sample records for regulates myeloid-cell dependent

  1. Tissue type plasminogen activator regulates myeloid-cell dependent neoangiogenesis during tissue regeneration

    DEFF Research Database (Denmark)

    Ohki, Makiko; Ohki, Yuichi; Ishihara, Makoto

    2010-01-01

    tissue regeneration is not well understood. Bone marrow (BM)-derived myeloid cells facilitate angiogenesis during tissue regeneration. Here, we report that a serpin-resistant form of tPA by activating the extracellular proteases matrix metalloproteinase-9 and plasmin expands the myeloid cell pool......-A. Remarkably, transplantation of BM-derived tPA-mobilized CD11b(+) cells and VEGFR-1(+) cells, but not carrier-mobilized cells or CD11b(-) cells, accelerates neovascularization and ischemic tissue regeneration. Inhibition of VEGF signaling suppresses tPA-induced neovascularization in a model of hind limb...... and mobilizes CD45(+)CD11b(+) proangiogenic, myeloid cells, a process dependent on vascular endothelial growth factor-A (VEGF-A) and Kit ligand signaling. tPA improves the incorporation of CD11b(+) cells into ischemic tissues and increases expression of neoangiogenesis-related genes, including VEGF...

  2. β-Catenin–regulated myeloid cell adhesion and migration determine wound healing

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    Amini-Nik, Saeid; Cambridge, Elizabeth; Yu, Winston; Guo, Anne; Whetstone, Heather; Nadesan, Puviindran; Poon, Raymond; Hinz, Boris; Alman, Benjamin A.

    2014-01-01

    A β-catenin/T cell factor–dependent transcriptional program is critical during cutaneous wound repair for the regulation of scar size; however, the relative contribution of β-catenin activity and function in specific cell types in the granulation tissue during the healing process is unknown. Here, cell lineage tracing revealed that cells in which β-catenin is transcriptionally active express a gene profile that is characteristic of the myeloid lineage. Mice harboring a macrophage-specific deletion of the gene encoding β-catenin exhibited insufficient skin wound healing due to macrophage-specific defects in migration, adhesion to fibroblasts, and ability to produce TGF-β1. In irradiated mice, only macrophages expressing β-catenin were able to rescue wound-healing deficiency. Evaluation of scar tissue collected from patients with hypertrophic and normal scars revealed a correlation between the number of macrophages within the wound, β-catenin levels, and cellularity. Our data indicate that β-catenin regulates myeloid cell motility and adhesion and that β-catenin–mediated macrophage motility contributes to the number of mesenchymal cells and ultimate scar size following cutaneous injury. PMID:24837430

  3. Influence of DNA-methylation on zinc homeostasis in myeloid cells: Regulation of zinc transporters and zinc binding proteins.

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    Kessels, Jana Elena; Wessels, Inga; Haase, Hajo; Rink, Lothar; Uciechowski, Peter

    2016-09-01

    The distribution of intracellular zinc, predominantly regulated through zinc transporters and zinc binding proteins, is required to support an efficient immune response. Epigenetic mechanisms such as DNA methylation are involved in the expression of these genes. In demethylation experiments using 5-Aza-2'-deoxycytidine (AZA) increased intracellular (after 24 and 48h) and total cellular zinc levels (after 48h) were observed in the myeloid cell line HL-60. To uncover the mechanisms that cause the disturbed zinc homeostasis after DNA demethylation, the expression of human zinc transporters and zinc binding proteins were investigated. Real time PCR analyses of 14 ZIP (solute-linked carrier (SLC) SLC39A; Zrt/IRT-like protein), and 9 ZnT (SLC30A) zinc transporters revealed significantly enhanced mRNA expression of the zinc importer ZIP1 after AZA treatment. Because ZIP1 protein was also enhanced after AZA treatment, ZIP1 up-regulation might be the mediator of enhanced intracellular zinc levels. The mRNA expression of ZIP14 was decreased, whereas zinc exporter ZnT3 mRNA was also significantly increased; which might be a cellular reaction to compensate elevated zinc levels. An enhanced but not significant chromatin accessibility of ZIP1 promoter region I was detected by chromatin accessibility by real-time PCR (CHART) assays after demethylation. Additionally, DNA demethylation resulted in increased mRNA accumulation of zinc binding proteins metallothionein (MT) and S100A8/S100A9 after 48h. MT mRNA was significantly enhanced after 24h of AZA treatment also suggesting a reaction of the cell to restore zinc homeostasis. These data indicate that DNA methylation is an important epigenetic mechanism affecting zinc binding proteins and transporters, and, therefore, regulating zinc homeostasis in myeloid cells. Copyright © 2016 Elsevier GmbH. All rights reserved.

  4. Leishmania Hijacks Myeloid Cells for Immune Escape

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    María Martínez-López

    2018-05-01

    Full Text Available Protozoan parasites of the Leishmania genus are the causative agents of leishmaniasis, a group of neglected tropical diseases whose clinical manifestations vary depending on the infectious Leishmania species but also on host factors. Recognition of the parasite by host myeloid immune cells is a key to trigger an effective Leishmania-specific immunity. However, the parasite is able to persist in host myeloid cells by evading, delaying and manipulating host immunity in order to escape host resistance and ensure its transmission. Neutrophils are first in infiltrating infection sites and could act either favoring or protecting against infection, depending on factors such as the genetic background of the host or the parasite species. Macrophages are the main host cells where the parasites grow and divide. However, macrophages are also the main effector population involved in parasite clearance. Parasite elimination by macrophages requires the priming and development of an effector Th1 adaptive immunity driven by specific subtypes of dendritic cells. Herein, we will provide a comprehensive outline of how myeloid cells regulate innate and adaptive immunity against Leishmania, and the mechanisms used by the parasites to promote their evasion and sabotage. Understanding the interactions between Leishmania and the host myeloid cells may lead to the development of new therapeutic approaches and improved vaccination to leishmaniases, an important worldwide health problem in which current therapeutic or preventive approaches are limited.

  5. The farnesoid-X-receptor in myeloid cells controls CNS autoimmunity in an IL-10-dependent fashion.

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    Hucke, Stephanie; Herold, Martin; Liebmann, Marie; Freise, Nicole; Lindner, Maren; Fleck, Ann-Katrin; Zenker, Stefanie; Thiebes, Stephanie; Fernandez-Orth, Juncal; Buck, Dorothea; Luessi, Felix; Meuth, Sven G; Zipp, Frauke; Hemmer, Bernhard; Engel, Daniel Robert; Roth, Johannes; Kuhlmann, Tanja; Wiendl, Heinz; Klotz, Luisa

    2016-09-01

    Innate immune responses by myeloid cells decisively contribute to perpetuation of central nervous system (CNS) autoimmunity and their pharmacologic modulation represents a promising strategy to prevent disease progression in Multiple Sclerosis (MS). Based on our observation that peripheral immune cells from relapsing-remitting and primary progressive MS patients exhibited strongly decreased levels of the bile acid receptor FXR (farnesoid-X-receptor, NR1H4), we evaluated its potential relevance as therapeutic target for control of established CNS autoimmunity. Pharmacological FXR activation promoted generation of anti-inflammatory macrophages characterized by arginase-1, increased IL-10 production, and suppression of T cell responses. In mice, FXR activation ameliorated CNS autoimmunity in an IL-10-dependent fashion and even suppressed advanced clinical disease upon therapeutic administration. In analogy to rodents, pharmacological FXR activation in human monocytes from healthy controls and MS patients induced an anti-inflammatory phenotype with suppressive properties including control of effector T cell proliferation. We therefore, propose an important role of FXR in control of T cell-mediated autoimmunity by promoting anti-inflammatory macrophage responses.

  6. Cytokine Networks between Innate Lymphoid Cells and Myeloid Cells.

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    Mortha, Arthur; Burrows, Kyle

    2018-01-01

    Innate lymphoid cells (ILCs) are an essential component of the innate immune system in vertebrates. They are developmentally rooted in the lymphoid lineage and can diverge into at least three transcriptionally distinct lineages. ILCs seed both lymphoid and non-lymphoid tissues and are locally self-maintained in tissue-resident pools. Tissue-resident ILCs execute important effector functions making them key regulator in tissue homeostasis, repair, remodeling, microbial defense, and anti-tumor immunity. Similar to T lymphocytes, ILCs possess only few sensory elements for the recognition of non-self and thus depend on extrinsic cellular sensory elements residing within the tissue. Myeloid cells, including mononuclear phagocytes (MNPs), are key sentinels of the tissue and are able to translate environmental cues into an effector profile that instructs lymphocyte responses. The adaptation of myeloid cells to the tissue state thus influences the effector program of ILCs and serves as an example of how environmental signals are integrated into the function of ILCs via a tissue-resident immune cell cross talks. This review summarizes our current knowledge on the role of myeloid cells in regulating ILC functions and discusses how feedback communication between ILCs and myeloid cells contribute to stabilize immune homeostasis in order to maintain the healthy state of an organ.

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

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

    2015-08-27

    Repeated social defeat (RSD) in mice causes myeloid cell trafficking to the brain that contributes to the development of prolonged anxiety-like behavior. Myeloid cell recruitment following RSD occurs in regions where neuronal and microglia activation is observed. Thus, we hypothesized that crosstalk between neurons, microglia, and endothelial cells contributes to brain myeloid cell trafficking via chemokine signaling and vascular adhesion molecules. Here we show that social defeat caused an exposure- and brain region-dependent increase in several key adhesion molecules and chemokines involved in the recruitment of myeloid cells. For example, RSD induced distinct patterns of adhesion molecule expression that may explain brain region-dependent myeloid cell trafficking. VCAM-1 and ICAM-1 mRNA expression were increased in an exposure-dependent manner. Furthermore, RSD-induced VCAM-1 and ICAM-1 protein expression were localized to the vasculature of brain regions implicated in fear and anxiety responses, which spatially corresponded to previously reported patterns of myeloid cell trafficking. Next, mRNA expression of additional adhesion molecules (E- and P-selectin, PECAM-1) and chemokines (CXCL1, CXCL2, CXCL12, CCL2) were determined in the brain. Social defeat induced an exposure-dependent increase in mRNA levels of E-selectin, CXCL1, and CXCL2 that increased with additional days of social defeat. While CXCL12 was unaffected by RSD, CCL2 expression was increased by six days of social defeat. Last, comparison between enriched CD11b(+) cells (microglia/macrophages) and enriched GLAST-1(+)/CD11b(-) cells (astrocytes) revealed RSD increased mRNA expression of IL-1β, CCL2, and CXCL2 in microglia/macrophages but not in astrocytes. Collectively, these data indicate that key mediators of leukocyte recruitment were increased in the brain vasculature following RSD in an exposure- and brain region-dependent manner. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights

  8. Regulatory Myeloid Cells in Transplantation

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    Rosborough, Brian R.; Raïch-Regué, Dàlia; Turnquist, Heth R.; Thomson, Angus W.

    2013-01-01

    Regulatory myeloid cells (RMC) are emerging as novel targets for immunosuppressive (IS) agents and hold considerable promise as cellular therapeutic agents. Herein, we discuss the ability of regulatory macrophages (Mreg), regulatory dendritic cells (DCreg) and myeloid-derived suppressor cells (MDSC) to regulate alloimmunity, their potential as cellular therapeutic agents and the IS agents that target their function. We consider protocols for the generation of RMC and the selection of donor- or recipient-derived cells for adoptive cell therapy. Additionally, the issues of cell trafficking and antigen (Ag) specificity following RMC transfer are discussed. Improved understanding of the immunobiology of these cells has increased the possibility of moving RMC into the clinic to reduce the burden of current IS agents and promote Ag-specific tolerance. In the second half of this review, we discuss the influence of established and experimental IS agents on myeloid cell populations. IS agents believed historically to act primarily on T cell activation and proliferation are emerging as important regulators of RMC function. Better insights into the influence of IS agents on RMC will enhance our ability to develop cell therapy protocols to promote the function of these cells. Moreover, novel IS agents may be designed to target RMC in situ to promote Ag-specific immune regulation in transplantation and usher in a new era of immune modulation exploiting cells of myeloid origin. PMID:24092382

  9. Cycloheximide Can Induce Bax/Bak Dependent Myeloid Cell Death Independently of Multiple BH3-Only Proteins.

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    Katharine J Goodall

    Full Text Available Apoptosis mediated by Bax or Bak is usually thought to be triggered by BH3-only members of the Bcl-2 protein family. BH3-only proteins can directly bind to and activate Bax or Bak, or indirectly activate them by binding to anti-apoptotic Bcl-2 family members, thereby relieving their inhibition of Bax and Bak. Here we describe a third way of activation of Bax/Bak dependent apoptosis that does not require triggering by multiple BH3-only proteins. In factor dependent myeloid (FDM cell lines, cycloheximide induced apoptosis by a Bax/Bak dependent mechanism, because Bax-/-Bak-/- lines were profoundly resistant, whereas FDM lines lacking one or more genes for BH3-only proteins remained highly sensitive. Addition of cycloheximide led to the rapid loss of Mcl-1 but did not affect the expression of other Bcl-2 family proteins. In support of these findings, similar results were observed by treating FDM cells with the CDK inhibitor, roscovitine. Roscovitine reduced Mcl-1 abundance and caused Bax/Bak dependent cell death, yet FDM lines lacking one or more genes for BH3-only proteins remained highly sensitive. Therefore Bax/Bak dependent apoptosis can be regulated by the abundance of anti-apoptotic Bcl-2 family members such as Mcl-1, independently of several known BH3-only proteins.

  10. Distinct regulation of c-myb gene expression by HoxA9, Meis1 and Pbx proteins in normal hematopoietic progenitors and transformed myeloid cells

    International Nuclear Information System (INIS)

    Dassé, E; Volpe, G; Walton, D S; Wilson, N; Del Pozzo, W; O'Neill, L P; Slany, R K; Frampton, J; Dumon, S

    2012-01-01

    The proto-oncogenic protein c-Myb is an essential regulator of hematopoiesis and is frequently deregulated in hematological diseases such as lymphoma and leukemia. To gain insight into the mechanisms underlying the aberrant expression of c-Myb in myeloid leukemia, we analyzed and compared c-myb gene transcriptional regulation using two cell lines modeling normal hematopoietic progenitor cells (HPCs) and transformed myelomonocytic blasts. We report that the transcription factors HoxA9, Meis1, Pbx1 and Pbx2 bind in vivo to the c-myb locus and maintain its expression through different mechanisms in HPCs and leukemic cells. Our analysis also points to a critical role for Pbx2 in deregulating c-myb expression in murine myeloid cells cotransformed by the cooperative activity of HoxA9 and Meis1. This effect is associated with an intronic positioning of epigenetic marks and RNA polymerase II binding in the orthologous region of a previously described alternative promoter for c-myb. Taken together, our results could provide a first hint to explain the abnormal expression of c-myb in leukemic cells

  11. Rho GTPase expression in human myeloid cells.

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    Suzanne F G van Helden

    Full Text Available Myeloid cells are critical for innate immunity and the initiation of adaptive immunity. Strict regulation of the adhesive and migratory behavior is essential for proper functioning of these cells. Rho GTPases are important regulators of adhesion and migration; however, it is unknown which Rho GTPases are expressed in different myeloid cells. Here, we use a qPCR-based approach to investigate Rho GTPase expression in myeloid cells.We found that the mRNAs encoding Cdc42, RhoQ, Rac1, Rac2, RhoA and RhoC are the most abundant. In addition, RhoG, RhoB, RhoF and RhoV are expressed at low levels or only in specific cell types. More differentiated cells along the monocyte-lineage display lower levels of Cdc42 and RhoV, while RhoC mRNA is more abundant. In addition, the Rho GTPase expression profile changes during dendritic cell maturation with Rac1 being upregulated and Rac2 downregulated. Finally, GM-CSF stimulation, during macrophage and osteoclast differentiation, leads to high expression of Rac2, while M-CSF induces high levels of RhoA, showing that these cytokines induce a distinct pattern. Our data uncover cell type specific modulation of the Rho GTPase expression profile in hematopoietic stem cells and in more differentiated cells of the myeloid lineage.

  12. Deficiency of leptin receptor in myeloid cells disrupts hypothalamic metabolic circuits and causes body weight increase

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    Yuanqing Gao

    2018-01-01

    Conclusions: Myeloid cell leptin receptor deficient mice partially replicate the db/db phenotype. Leptin signaling in hypothalamic microglia is important for microglial function and a correct formation of the hypothalamic neuronal circuit regulating metabolism.

  13. Regulation of Human Macrophage M1–M2 Polarization Balance by Hypoxia and the Triggering Receptor Expressed on Myeloid Cells-1

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    Federica Raggi

    2017-09-01

    Full Text Available Macrophages (Mf are a heterogeneous population of tissue-resident professional phagocytes and a major component of the leukocyte infiltrate at sites of inflammation, infection, and tumor growth. They can undergo diverse forms of activation in response to environmental factors, polarizing into specialized functional subsets. A common hallmark of the pathologic environment is represented by hypoxia. The impact of hypoxia on human Mf polarization has not been fully established. The objective of this study was to elucidate the effects of a hypoxic environment reflecting that occurring in vivo in diseased tissues on the ability of human Mf to polarize into classically activated (proinflammatory M1 and alternatively activated (anti-inflammatory M2 subsets. We present data showing that hypoxia hinders Mf polarization toward the M1 phenotype by decreasing the expression of T cell costimulatory molecules and chemokine homing receptors and the production of proinflammatory, Th1-priming cytokines typical of classical activation, while promoting their acquisition of phenotypic and secretory features of alternative activation. Furthermore, we identify the triggering receptor expressed on myeloid cells (TREM-1, a member of the Ig-like immunoregulatory receptor family, as a hypoxia-inducible gene in Mf and demonstrate that its engagement by an agonist Ab reverses the M2-polarizing effect of hypoxia imparting a M1-skewed phenotype to Mf. Finally, we provide evidence that Mf infiltrating the inflamed hypoxic joints of children affected by oligoarticular juvenile idiopatic arthritis express high surface levels of TREM-1 associated with predominant M1 polarization and suggest the potential of this molecule in driving M1 proinflammatory reprogramming in the hypoxic synovial environment.

  14. Regulation of Human Macrophage M1–M2 Polarization Balance by Hypoxia and the Triggering Receptor Expressed on Myeloid Cells-1

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    Raggi, Federica; Pelassa, Simone; Pierobon, Daniele; Penco, Federica; Gattorno, Marco; Novelli, Francesco; Eva, Alessandra; Varesio, Luigi; Giovarelli, Mirella; Bosco, Maria Carla

    2017-01-01

    Macrophages (Mf) are a heterogeneous population of tissue-resident professional phagocytes and a major component of the leukocyte infiltrate at sites of inflammation, infection, and tumor growth. They can undergo diverse forms of activation in response to environmental factors, polarizing into specialized functional subsets. A common hallmark of the pathologic environment is represented by hypoxia. The impact of hypoxia on human Mf polarization has not been fully established. The objective of this study was to elucidate the effects of a hypoxic environment reflecting that occurring in vivo in diseased tissues on the ability of human Mf to polarize into classically activated (proinflammatory M1) and alternatively activated (anti-inflammatory M2) subsets. We present data showing that hypoxia hinders Mf polarization toward the M1 phenotype by decreasing the expression of T cell costimulatory molecules and chemokine homing receptors and the production of proinflammatory, Th1-priming cytokines typical of classical activation, while promoting their acquisition of phenotypic and secretory features of alternative activation. Furthermore, we identify the triggering receptor expressed on myeloid cells (TREM)-1, a member of the Ig-like immunoregulatory receptor family, as a hypoxia-inducible gene in Mf and demonstrate that its engagement by an agonist Ab reverses the M2-polarizing effect of hypoxia imparting a M1-skewed phenotype to Mf. Finally, we provide evidence that Mf infiltrating the inflamed hypoxic joints of children affected by oligoarticular juvenile idiopatic arthritis express high surface levels of TREM-1 associated with predominant M1 polarization and suggest the potential of this molecule in driving M1 proinflammatory reprogramming in the hypoxic synovial environment. PMID:28936211

  15. Tissue factor expression by myeloid cells contributes to protective immune response against Mycobacterium tuberculosis infection.

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    Venkatasubramanian, Sambasivan; Tripathi, Deepak; Tucker, Torry; Paidipally, Padmaja; Cheekatla, Satyanarayana; Welch, Elwyn; Raghunath, Anjana; Jeffers, Ann; Tvinnereim, Amy R; Schechter, Melissa E; Andrade, Bruno B; Mackman, Nizel; Idell, Steven; Vankayalapati, Ramakrishna

    2016-02-01

    Tissue factor (TF) is a transmembrane glycoprotein that plays an essential role in hemostasis by activating coagulation. TF is also expressed by monocytes/macrophages as part of the innate immune response to infections. In the current study, we determined the role of TF expressed by myeloid cells during Mycobacterium tuberculosis (M. tb) infection by using mice lacking the TF gene in myeloid cells (TF(Δ) ) and human monocyte derived macrophages (MDMs). We found that during M. tb infection, a deficiency of TF in myeloid cells was associated with reduced inducible nitric oxide synthase (iNOS) expression, enhanced arginase 1 (Arg1) expression, enhanced IL-10 production and reduced apoptosis in infected macrophages, which augmented M. tb growth. Our results demonstrate that a deficiency of TF in myeloid cells promotes M2-like phenotype in M .tb infected macrophages. A deficiency in TF expression by myeloid cells was also associated with reduced fibrin deposition and increased matrix metalloproteases (MMP)-2 and MMP-9 mediated inflammation in M. tb infected lungs. Our studies demonstrate that TF expressed by myeloid cells has newly recognized abilities to polarize macrophages and to regulate M. tb growth. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Lumbar Myeloid Cell Trafficking into Locomotor Networks after Thoracic Spinal Cord Injury

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    Hansen, Christopher N.; Norden, Diana M.; Faw, Timothy D.; Deibert, Rochelle; S.Wohleb, Eric; Sheridan, John F.; P.Godbout, Jonathan; Basso, D. Michele

    2016-01-01

    Spinal cord injury (SCI) promotes inflammation along the neuroaxis that jeopardizes plasticity, intrinsic repair and recovery. While inflammation at the injury site is well-established, less is known within remote spinal networks. The presence of bone marrow-derived immune (myeloid) cells in these areas may further impede functional recovery. Previously, high levels of the gelatinase, matrix metalloproteinase-9 (MMP-9) occurred within the lumbar enlargement after thoracic SCI and impeded activity-dependent recovery. Since SCI-induced MMP-9 potentially increases vascular permeability, myeloid cell infiltration may drive inflammatory toxicity in locomotor networks. Therefore, we examined neurovascular reactivity and myeloid cell infiltration in the lumbar cord after thoracic SCI. We show evidence of region-specific recruitment of myeloid cells into the lumbar but not cervical region. Myeloid infiltration occurred with concomitant increases in chemoattractants (CCL2) and cell adhesion molecules (ICAM-1) around lumbar vasculature 24 hours and 7 days post injury. Bone marrow GFP chimeric mice established robust infiltration of bone marrow-derived myeloid cells into the lumbar gray matter 24 hours after SCI. This cell infiltration occurred when the blood-spinal cord barrier was intact, suggesting active recruitment across the endothelium. Myeloid cells persisted as ramified macrophages at 7 days post injury in parallel with increased inhibitory GAD67 labeling. Importantly, macrophage infiltration required MMP-9. PMID:27191729

  17. IKKα Promotes Intestinal Tumorigenesis by Limiting Recruitment of M1-like Polarized Myeloid Cells

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    Serkan I. Göktuna

    2014-06-01

    Full Text Available The recruitment of immune cells into solid tumors is an essential prerequisite of tumor development. Depending on the prevailing polarization profile of these infiltrating leucocytes, tumorigenesis is either promoted or blocked. Here, we identify IκB kinase α (IKKα as a central regulator of a tumoricidal microenvironment during intestinal carcinogenesis. Mice deficient in IKKα kinase activity are largely protected from intestinal tumor development that is dependent on the enhanced recruitment of interferon γ (IFNγ-expressing M1-like myeloid cells. In IKKα mutant mice, M1-like polarization is not controlled in a cell-autonomous manner but, rather, depends on the interplay of both IKKα mutant tumor epithelia and immune cells. Because therapies aiming at the tumor microenvironment rather than directly at the mutated cancer cell may circumvent resistance development, we suggest IKKα as a promising target for colorectal cancer (CRC therapy.

  18. The Role of MicroRNAs in Myeloid Cells during Graft-versus-Host Disease

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    Sophia Chen

    2018-01-01

    Full Text Available The successful treatment of various hematologic diseases with allogeneic hematopoietic cell transplantation is often limited by the occurrence of graft-versus-host disease (GvHD. Several microRNAs (miRs have recently been shown to impact the biology of GvHD by regulating pro- as well as anti-inflammatory target genes. There is increasing evidence that a single miR can have different effects by preferentially targeting certain genes depending on the cell type that the miR is analyzed in. This review will focus on the role of miRs in myeloid cells during the development of acute and chronic GvHD and autoimmune diseases. Because miRs act on the expression of multiple target genes and may thereby influence the immune system at different functional levels, they are potentially attractive targets for the modification of allogeneic immune responses using miR mimics and inhibitors.

  19. Tunneling Nanotubes: Intimate Communication between Myeloid Cells.

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    Dupont, Maeva; Souriant, Shanti; Lugo-Villarino, Geanncarlo; Maridonneau-Parini, Isabelle; Vérollet, Christel

    2018-01-01

    Tunneling nanotubes (TNT) are dynamic connections between cells, which represent a novel route for cell-to-cell communication. A growing body of evidence points TNT towards a role for intercellular exchanges of signals, molecules, organelles, and pathogens, involving them in a diverse array of functions. TNT form among several cell types, including neuronal cells, epithelial cells, and almost all immune cells. In myeloid cells (e.g., macrophages, dendritic cells, and osteoclasts), intercellular communication via TNT contributes to their differentiation and immune functions. Importantly, TNT enable myeloid cells to communicate with a targeted neighboring or distant cell, as well as with other cell types, therefore creating a complex variety of cellular exchanges. TNT also contribute to pathogen spread as they serve as "corridors" from a cell to another. Herein, we addressed the complexity of the definition and in vitro characterization of TNT in innate immune cells, the different processes involved in their formation, and their relevance in vivo . We also assess our current understanding of how TNT participate in immune surveillance and the spread of pathogens, with a particular interest for HIV-1. Overall, despite recent progress in this growing research field, we highlight that further investigation is needed to better unveil the role of TNT in both physiological and pathological conditions.

  20. Tunneling Nanotubes: Intimate Communication between Myeloid Cells

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    Maeva Dupont

    2018-01-01

    Full Text Available Tunneling nanotubes (TNT are dynamic connections between cells, which represent a novel route for cell-to-cell communication. A growing body of evidence points TNT towards a role for intercellular exchanges of signals, molecules, organelles, and pathogens, involving them in a diverse array of functions. TNT form among several cell types, including neuronal cells, epithelial cells, and almost all immune cells. In myeloid cells (e.g., macrophages, dendritic cells, and osteoclasts, intercellular communication via TNT contributes to their differentiation and immune functions. Importantly, TNT enable myeloid cells to communicate with a targeted neighboring or distant cell, as well as with other cell types, therefore creating a complex variety of cellular exchanges. TNT also contribute to pathogen spread as they serve as “corridors” from a cell to another. Herein, we addressed the complexity of the definition and in vitro characterization of TNT in innate immune cells, the different processes involved in their formation, and their relevance in vivo. We also assess our current understanding of how TNT participate in immune surveillance and the spread of pathogens, with a particular interest for HIV-1. Overall, despite recent progress in this growing research field, we highlight that further investigation is needed to better unveil the role of TNT in both physiological and pathological conditions.

  1. Chronic inflammation triggered by the NLRP3 inflammasome in myeloid cells promotes growth plate dysplasia by mesenchymal cells.

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    Wang, Chun; Xu, Can-Xin; Alippe, Yael; Qu, Chao; Xiao, Jianqiu; Schipani, Ernestina; Civitelli, Roberto; Abu-Amer, Yousef; Mbalaviele, Gabriel

    2017-07-07

    Skeletal complications are common features of neonatal-onset multisystem inflammatory disease (NOMID), a disorder caused by NLRP3-activating mutations. NOMID mice in which NLRP3 is activated globally exhibit several characteristics of the human disease, including systemic inflammation and cartilage dysplasia, but the mechanisms of skeletal manifestations remain unknown. In this study, we find that activation of NLRP3 in myeloid cells, but not mesenchymal cells triggers chronic inflammation, which ultimately, causes growth plate and epiphyseal dysplasia in mice. These responses are IL-1 signaling-dependent, but independent of PARP1, which also functions downstream of NLRP3 and regulates skeletal homeostasis. Mechanistically, inflammation causes severe anemia and hypoxia in the bone environment, yet down-regulates the HIF-1α pathway in chondrocytes, thereby promoting the demise of these cells. Thus, activation of NLRP3 in hematopoietic cells initiates IL-1β-driven paracrine cascades, which promote abnormal growth plate development in NOMID mice.

  2. Activated factor X signaling via protease-activated receptor 2 suppresses pro-inflammatory cytokine production from LPS-stimulated myeloid cells.

    LENUS (Irish Health Repository)

    Gleeson, Eimear M

    2013-07-19

    -associated protein-sensitive, protease-activated receptor 2-dependent regulator of myeloid cell pro-inflammatory cytokine production.

  3. CD13-positive bone marrow-derived myeloid cells promote angiogenesis, tumor growth, and metastasis.

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    Dondossola, Eleonora; Rangel, Roberto; Guzman-Rojas, Liliana; Barbu, Elena M; Hosoya, Hitomi; St John, Lisa S; Molldrem, Jeffrey J; Corti, Angelo; Sidman, Richard L; Arap, Wadih; Pasqualini, Renata

    2013-12-17

    Angiogenesis is fundamental to tumorigenesis and an attractive target for therapeutic intervention against cancer. We have recently demonstrated that CD13 (aminopeptidase N) expressed by nonmalignant host cells of unspecified types regulate tumor blood vessel development. Here, we compare CD13 wild-type and null bone marrow-transplanted tumor-bearing mice to show that host CD13(+) bone marrow-derived cells promote cancer progression via their effect on angiogenesis. Furthermore, we have identified CD11b(+)CD13(+) myeloid cells as the immune subpopulation directly regulating tumor blood vessel development. Finally, we show that these cells are specifically localized within the tumor microenvironment and produce proangiogenic soluble factors. Thus, CD11b(+)CD13(+) myeloid cells constitute a population of bone marrow-derived cells that promote tumor progression and metastasis and are potential candidates for the development of targeted antiangiogenic drugs.

  4. A20 (Tnfaip3 deficiency in myeloid cells protects against influenza A virus infection.

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    Jonathan Maelfait

    Full Text Available The innate immune response provides the first line of defense against viruses and other pathogens by responding to specific microbial molecules. Influenza A virus (IAV produces double-stranded RNA as an intermediate during the replication life cycle, which activates the intracellular pathogen recognition receptor RIG-I and induces the production of proinflammatory cytokines and antiviral interferon. Understanding the mechanisms that regulate innate immune responses to IAV and other viruses is of key importance to develop novel therapeutic strategies. Here we used myeloid cell specific A20 knockout mice to examine the role of the ubiquitin-editing protein A20 in the response of myeloid cells to IAV infection. A20 deficient macrophages were hyperresponsive to double stranded RNA and IAV infection, as illustrated by enhanced NF-κB and IRF3 activation, concomitant with increased production of proinflammatory cytokines, chemokines and type I interferon. In vivo this was associated with an increased number of alveolar macrophages and neutrophils in the lungs of IAV infected mice. Surprisingly, myeloid cell specific A20 knockout mice are protected against lethal IAV infection. These results challenge the general belief that an excessive host proinflammatory response is associated with IAV-induced lethality, and suggest that under certain conditions inhibition of A20 might be of interest in the management of IAV infections.

  5. Systemic RNAi-mediated Gene Silencing in Nonhuman Primate and Rodent Myeloid Cells

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    Tatiana I Novobrantseva

    2012-01-01

    Full Text Available Leukocytes are central regulators of inflammation and the target cells of therapies for key diseases, including autoimmune, cardiovascular, and malignant disorders. Efficient in vivo delivery of small interfering RNA (siRNA to immune cells could thus enable novel treatment strategies with broad applicability. In this report, we develop systemic delivery methods of siRNA encapsulated in lipid nanoparticles (LNP for durable and potent in vivo RNA interference (RNAi-mediated silencing in myeloid cells. This work provides the first demonstration of siRNA-mediated silencing in myeloid cell types of nonhuman primates (NHPs and establishes the feasibility of targeting multiple gene targets in rodent myeloid cells. The therapeutic potential of these formulations was demonstrated using siRNA targeting tumor necrosis factor-α (TNFα which induced substantial attenuation of disease progression comparable to a potent antibody treatment in a mouse model of rheumatoid arthritis (RA. In summary, we demonstrate a broadly applicable and therapeutically relevant platform for silencing disease genes in immune cells.

  6. Identification of Reprogrammed Myeloid Cell Transcriptomes in NSCLC.

    Directory of Open Access Journals (Sweden)

    Anna Durrans

    Full Text Available Lung cancer is the leading cause of cancer related mortality worldwide, with non-small cell lung cancer (NSCLC as the most prevalent form. Despite advances in treatment options including minimally invasive surgery, CT-guided radiation, novel chemotherapeutic regimens, and targeted therapeutics, prognosis remains dismal. Therefore, further molecular analysis of NSCLC is necessary to identify novel molecular targets that impact prognosis and the design of new-targeted therapies. In recent years, tumor "activated/reprogrammed" stromal cells that promote carcinogenesis have emerged as potential therapeutic targets. However, the contribution of stromal cells to NSCLC is poorly understood. Here, we show increased numbers of bone marrow (BM-derived hematopoietic cells in the tumor parenchyma of NSCLC patients compared with matched adjacent non-neoplastic lung tissue. By sorting specific cellular fractions from lung cancer patients, we compared the transcriptomes of intratumoral myeloid compartments within the tumor bed with their counterparts within adjacent non-neoplastic tissue from NSCLC patients. The RNA sequencing of specific myeloid compartments (immature monocytic myeloid cells and polymorphonuclear neutrophils identified differentially regulated genes and mRNA isoforms, which were inconspicuous in whole tumor analysis. Genes encoding secreted factors, including osteopontin (OPN, chemokine (C-C motif ligand 7 (CCL7 and thrombospondin 1 (TSP1 were identified, which enhanced tumorigenic properties of lung cancer cells indicative of their potential as targets for therapy. This study demonstrates that analysis of homogeneous stromal populations isolated directly from fresh clinical specimens can detect important stromal genes of therapeutic value.

  7. CSF-1 Receptor Signaling in Myeloid Cells

    Science.gov (United States)

    Stanley, E. Richard; Chitu, Violeta

    2014-01-01

    The CSF-1 receptor (CSF-1R) is activated by the homodimeric growth factors colony-stimulating factor-1 (CSF-1) and interleukin-34 (IL-34). It plays important roles in development and in innate immunity by regulating the development of most tissue macrophages and osteoclasts, of Langerhans cells of the skin, of Paneth cells of the small intestine, and of brain microglia. It also regulates the differentiation of neural progenitor cells and controls functions of oocytes and trophoblastic cells in the female reproductive tract. Owing to this broad tissue expression pattern, it plays a central role in neoplastic, inflammatory, and neurological diseases. In this review we summarize the evolution, structure, and regulation of expression of the CSF-1R gene. We review, the structures of CSF-1, IL-34, and the CSF-1R and the mechanism of ligand binding to and activation of the receptor. We further describe the pathways regulating macrophage survival, proliferation, differentiation, and chemotaxis downstream from the CSF-1R. PMID:24890514

  8. Tumor-educated myeloid cells: impact the micro- and macroenvironment.

    Science.gov (United States)

    Becker, Jürgen C

    2014-03-01

    Immune escape mechanisms of cancers include some of the mechanisms normally used for immune homeostasis, particular those preventing autoimmunity; one of these is the polarisation of myeloid cells. Thereby, tumors, i.e. the cancerous and stromal cells, also condition distant sites like spleen and bone marrow via soluble factors and membrane vesicles such as exosomes in order to create a tumor-educated macroenvironment. Albeit these mechanisms are currently in the focus of (tumor-)immunologic research, the first evidence had been published almost 40 years ago. One of these early reports will be discussed here. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Radiation response of mouse lymphoid and myeloid cell lines. Pt. 3

    International Nuclear Information System (INIS)

    Radford, I.R.; Murphy, T.K.

    1994-01-01

    The authors have examined the timing of γ-irradiation-induced death in relation to cell cycle progression using a panel of mouse lymphoid or myeloid cell lines. Death was found to occur immediately after irradiation ('rapid interphase' death), or after arrest in G 2 phase ('delayed interphase' death), or following one or more mitoses ('mitotic/delayed mitotic' death). In part II of this series of papers the authors demonstrated the occurrence of radiation-induced apoptosis in all these cell lines. Several of the cell lines showed different timing of death dependent upon the radiation dose used. These differences in the timing of radiation-induced death are shown to be useful indicators of the relative radiosensitivity of haematopoietic cell lines. (author)

  10. Myeloid cells in Alzheimer's disease: culprits, victims or innocent bystanders?

    Science.gov (United States)

    Meyer-Luehmann, Melanie; Prinz, Marco

    2015-10-01

    Several recent genome-wide association studies (GWAS) in patients with neurodegenerative disorders have shed new light on the brain immune system, suggesting that it plays a pivotal role in disease pathogenesis. Mononuclear phagocytes are blatantly involved in Alzheimer's disease (AD) of the central nervous system (CNS), but the specific functions of resident microglia, perivascular or meningeal macrophages, and circulating myeloid cells have not yet been fully resolved. Next-generation sequencing, high-throughput immune profiling technologies, and novel genetic tools have recently revolutionized the characterization of innate immune responses during AD. These studies advocate selective and non-redundant roles for myeloid subsets, which could be a target for novel disease-modifying therapies in AD. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. The rate of spontaneous mutations in human myeloid cells

    International Nuclear Information System (INIS)

    Araten, David J.; Krejci, Ondrej; DiTata, Kimberly; Wunderlich, Mark; Sanders, Katie J.; Zamechek, Leah; Mulloy, James C.

    2013-01-01

    Highlights: • We provide the first measurement of the mutation rate (μ) in human myeloid cells. • μ is measured to be 3.6–23 × 10 −7 per cell division. • The AML-ETO and MLL-AF9 fusions do not seem to increase μ. • Cooperating mutations in NRAS, FLT3 and p53 not seem to increase μ. • Hypermutability may be required to explain leukemogenesis. - Abstract: The mutation rate (μ) is likely to be a key parameter in leukemogenesis, but historically, it has been difficult to measure in humans. The PIG-A gene has some advantages for the detection of spontaneous mutations because it is X-linked, and therefore only one mutation is required to disrupt its function. Furthermore, the PIG-A-null phenotype is readily detected by flow cytometry. Using PIG-A, we have now provided the first in vitro measurement of μ in myeloid cells, using cultures of CD34+ cells that are transduced with either the AML-ETO or the MLL-AF9 fusion genes and expanded with cytokines. For the AML-ETO cultures, the median μ value was ∼9.4 × 10 −7 (range ∼3.6–23 × 10 −7 ) per cell division. In contrast, few spontaneous mutations were observed in the MLL-AF9 cultures. Knockdown of p53 or introduction of mutant NRAS or FLT3 alleles did not have much of an effect on μ. Based on these data, we provide a model to predict whether hypermutability must occur in the process of leukemogenesis

  12. The DNA Inflammasome in Human Myeloid Cells Is Initiated by a STING-Cell Death Program Upstream of NLRP3

    Science.gov (United States)

    Gaidt, Moritz M.; Ebert, Thomas S.; Chauhan, Dhruv; Ramshorn, Katharina; Pinci, Francesca; Zuber, Sarah; O’Duill, Fionan; Schmid-Burgk, Jonathan L.; Hoss, Florian; Buhmann, Raymund; Wittmann, Georg; Latz, Eicke; Subklewe, Marion; Hornung, Veit

    2018-01-01

    Summary Detection of cytosolic DNA constitutes a central event in the context of numerous infectious and sterile inflammatory conditions. Recent studies have uncovered a bipartite mode of cytosolic DNA recognition, in which the cGAS-STING axis triggers antiviral immunity, whereas AIM2 triggers inflammasome activation. Here, we show that AIM2 is dispensable for DNA-mediated inflammasome activation in human myeloid cells. Instead, detection of cytosolic DNA by the cGAS-STING axis induces a cell death program initiating potassium efflux upstream of NLRP3. Forward genetics identified regulators of lysosomal trafficking to modulate this cell death program, and subsequent studies revealed that activated STING traffics to the lysosome, where it triggers membrane permeabilization and thus lysosomal cell death (LCD). Importantly, the cGAS-STING-NLRP3 pathway constitutes the default inflammasome response during viral and bacterial infections in human myeloid cells. We conclude that targeting the cGAS-STING-LCD-NLRP3 pathway will ameliorate pathology in inflammatory conditions that are associated with cytosolic DNA sensing. PMID:29033128

  13. Triggering receptor expressed on myeloid cells-2 fine-tunes inflammatory responses in murine Gram-negative sepsis

    DEFF Research Database (Denmark)

    Schmidt Thøgersen, Mariane; Gawish, Riem; Martins, Rui

    2015-01-01

    During infections, TLR-mediated responses require tight regulation to allow for pathogen removal, while preventing overwhelming inflammation and immunopathology. The triggering receptor expressed on myeloid cells (TREM)-2 negatively regulates inflammation by macrophages and impacts on phagocytosis...... was followed by an accelerated resolution and ultimately improved survival, associated with the induction of the negative regulator A20. Upon infection with Escherichia coli, the otherwise beneficial effect of an exaggerated early immune response in TREM-2(-/-) animals was counteracted by a 50% reduction...... in bacterial phagocytosis. In line with this, TREM-2(-/-) peritoneal macrophages (PMs) exhibited augmented inflammation following TLR4 stimulation, demonstrating the presence and negative regulatory functionality of TREM-2 on primary PMs. Significantly, we identified a high turnover rate because TREM-2 RNA...

  14. A Systems Approach Reveals MAVS Signaling in Myeloid Cells as Critical for Resistance to Ebola Virus in Murine Models of Infection

    Directory of Open Access Journals (Sweden)

    Mukta Dutta

    2017-01-01

    Full Text Available The unprecedented 2013–2016 outbreak of Ebola virus (EBOV resulted in over 11,300 human deaths. Host resistance to RNA viruses requires RIG-I-like receptor (RLR signaling through the adaptor protein, mitochondrial antiviral signaling protein (MAVS, but the role of RLR-MAVS in orchestrating anti-EBOV responses in vivo is not known. Here we apply a systems approach to MAVS−/− mice infected with either wild-type or mouse-adapted EBOV. MAVS controlled EBOV replication through the expression of IFNα, regulation of inflammatory responses in the spleen, and prevention of cell death in the liver, with macrophages implicated as a major cell type influencing host resistance. A dominant role for RLR signaling in macrophages was confirmed following conditional MAVS deletion in LysM+ myeloid cells. These findings reveal tissue-specific MAVS-dependent transcriptional pathways associated with resistance to EBOV, and they demonstrate that EBOV adaptation to cause disease in mice involves changes in two distinct events, RLR-MAVS antagonism and suppression of RLR-independent IFN-I responses.

  15. A Systems Approach Reveals MAVS Signaling in Myeloid Cells as Critical for Resistance to Ebola Virus in Murine Models of Infection.

    Science.gov (United States)

    Dutta, Mukta; Robertson, Shelly J; Okumura, Atsushi; Scott, Dana P; Chang, Jean; Weiss, Jeffrey M; Sturdevant, Gail L; Feldmann, Friederike; Haddock, Elaine; Chiramel, Abhilash I; Ponia, Sanket S; Dougherty, Jonathan D; Katze, Michael G; Rasmussen, Angela L; Best, Sonja M

    2017-01-17

    The unprecedented 2013-2016 outbreak of Ebola virus (EBOV) resulted in over 11,300 human deaths. Host resistance to RNA viruses requires RIG-I-like receptor (RLR) signaling through the adaptor protein, mitochondrial antiviral signaling protein (MAVS), but the role of RLR-MAVS in orchestrating anti-EBOV responses in vivo is not known. Here we apply a systems approach to MAVS -/- mice infected with either wild-type or mouse-adapted EBOV. MAVS controlled EBOV replication through the expression of IFNα, regulation of inflammatory responses in the spleen, and prevention of cell death in the liver, with macrophages implicated as a major cell type influencing host resistance. A dominant role for RLR signaling in macrophages was confirmed following conditional MAVS deletion in LysM+ myeloid cells. These findings reveal tissue-specific MAVS-dependent transcriptional pathways associated with resistance to EBOV, and they demonstrate that EBOV adaptation to cause disease in mice involves changes in two distinct events, RLR-MAVS antagonism and suppression of RLR-independent IFN-I responses. Published by Elsevier Inc.

  16. ATM facilitates mouse gammaherpesvirus reactivation from myeloid cells during chronic infection.

    Science.gov (United States)

    Kulinski, Joseph M; Darrah, Eric J; Broniowska, Katarzyna A; Mboko, Wadzanai P; Mounce, Bryan C; Malherbe, Laurent P; Corbett, John A; Gauld, Stephen B; Tarakanova, Vera L

    2015-09-01

    Gammaherpesviruses are cancer-associated pathogens that establish life-long infection in most adults. Insufficiency of Ataxia-Telangiectasia mutated (ATM) kinase leads to a poor control of chronic gammaherpesvirus infection via an unknown mechanism that likely involves a suboptimal antiviral response. In contrast to the phenotype in the intact host, ATM facilitates gammaherpesvirus reactivation and replication in vitro. We hypothesized that ATM mediates both pro- and antiviral activities to regulate chronic gammaherpesvirus infection in an immunocompetent host. To test the proposed proviral activity of ATM in vivo, we generated mice with ATM deficiency limited to myeloid cells. Myeloid-specific ATM deficiency attenuated gammaherpesvirus infection during the establishment of viral latency. The results of our study uncover a proviral role of ATM in the context of gammaherpesvirus infection in vivo and support a model where ATM combines pro- and antiviral functions to facilitate both gammaherpesvirus-specific T cell immune response and viral reactivation in vivo. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Checkpoints to the Brain: Directing Myeloid Cell Migration to the Central Nervous System

    Directory of Open Access Journals (Sweden)

    Meredith Harrison-Brown

    2016-12-01

    Full Text Available Myeloid cells are a unique subset of leukocytes with a diverse array of functions within the central nervous system during health and disease. Advances in understanding of the unique properties of these cells have inspired interest in their use as delivery vehicles for therapeutic genes, proteins, and drugs, or as “assistants” in the clean-up of aggregated proteins and other molecules when existing drainage systems are no longer adequate. The trafficking of myeloid cells from the periphery to the central nervous system is subject to complex cellular and molecular controls with several ‘checkpoints’ from the blood to their destination in the brain parenchyma. As important components of the neurovascular unit, the functional state changes associated with lineage heterogeneity of myeloid cells are increasingly recognized as important for disease progression. In this review, we discuss some of the cellular elements associated with formation and function of the neurovascular unit, and present an update on the impact of myeloid cells on central nervous system (CNS diseases in the laboratory and the clinic. We then discuss emerging strategies for harnessing the potential of site-directed myeloid cell homing to the CNS, and identify promising avenues for future research, with particular emphasis on the importance of untangling the functional heterogeneity within existing myeloid subsets.

  18. Peripherally administered nanoparticles target monocytic myeloid cells, secondary lymphoid organs and tumors in mice.

    Directory of Open Access Journals (Sweden)

    Iraklis C Kourtis

    Full Text Available Nanoparticles have been extensively developed for therapeutic and diagnostic applications. While the focus of nanoparticle trafficking in vivo has traditionally been on drug delivery and organ-level biodistribution and clearance, recent work in cancer biology and infectious disease suggests that targeting different cells within a given organ can substantially affect the quality of the immunological response. Here, we examine the cell-level biodistribution kinetics after administering ultrasmall Pluronic-stabilized poly(propylene sulfide nanoparticles in the mouse. These nanoparticles depend on lymphatic drainage to reach the lymph nodes and blood, and then enter the spleen rather than the liver, where they interact with monocytes, macrophages and myeloid dendritic cells. They were more readily taken up into lymphatics after intradermal (i.d. compared to intramuscular administration, leading to ∼50% increased bioavailability in blood. When administered i.d., their distribution favored antigen-presenting cells, with especially strong targeting to myeloid cells. In tumor-bearing mice, the monocytic and the polymorphonuclear myeloid-derived suppressor cell compartments were efficiently and preferentially targeted, rendering this nanoparticulate formulation potentially useful for reversing the highly suppressive activity of these cells in the tumor stroma.

  19. Peripherally administered nanoparticles target monocytic myeloid cells, secondary lymphoid organs and tumors in mice.

    Science.gov (United States)

    Kourtis, Iraklis C; Hirosue, Sachiko; de Titta, Alexandre; Kontos, Stephan; Stegmann, Toon; Hubbell, Jeffrey A; Swartz, Melody A

    2013-01-01

    Nanoparticles have been extensively developed for therapeutic and diagnostic applications. While the focus of nanoparticle trafficking in vivo has traditionally been on drug delivery and organ-level biodistribution and clearance, recent work in cancer biology and infectious disease suggests that targeting different cells within a given organ can substantially affect the quality of the immunological response. Here, we examine the cell-level biodistribution kinetics after administering ultrasmall Pluronic-stabilized poly(propylene sulfide) nanoparticles in the mouse. These nanoparticles depend on lymphatic drainage to reach the lymph nodes and blood, and then enter the spleen rather than the liver, where they interact with monocytes, macrophages and myeloid dendritic cells. They were more readily taken up into lymphatics after intradermal (i.d.) compared to intramuscular administration, leading to ∼50% increased bioavailability in blood. When administered i.d., their distribution favored antigen-presenting cells, with especially strong targeting to myeloid cells. In tumor-bearing mice, the monocytic and the polymorphonuclear myeloid-derived suppressor cell compartments were efficiently and preferentially targeted, rendering this nanoparticulate formulation potentially useful for reversing the highly suppressive activity of these cells in the tumor stroma.

  20. A drug development perspective on targeting tumor-associated myeloid cells.

    Science.gov (United States)

    Majety, Meher; Runza, Valeria; Lehmann, Christian; Hoves, Sabine; Ries, Carola H

    2018-02-01

    Despite decades of research, cancer remains a devastating disease and new treatment options are needed. Today cancer is acknowledged as a multifactorial disease not only comprising of aberrant tumor cells but also the associated stroma including tumor vasculature, fibrotic plaques, and immune cells that interact in a complex heterotypic interplay. Myeloid cells represent one of the most abundant immune cell population within the tumor stroma and are equipped with a broad functional repertoire that promotes tumor growth by suppressing cytotoxic T cell activity, stimulating neoangiogenesis and tissue remodeling. Therefore, myeloid cells have become an attractive target for pharmacological intervention. In this review, we summarize the pharmacological approaches to therapeutically target tumor-associated myeloid cells with a focus on advanced programs that are clinically evaluated. In addition, for each therapeutic strategy, the preclinical rationale as well as advantages and challenges from a drug development perspective are discussed. © 2017 Federation of European Biochemical Societies.

  1. Soluble triggering receptor expressed on myeloid cells 1: a biomarker for bacterial meningitis

    NARCIS (Netherlands)

    Determann, Rogier M.; Weisfelt, Martijn; de Gans, Jan; van der Ende, Arie; Schultz, Marcus J.; van de Beek, Diederik

    2006-01-01

    OBJECTIVE: To evaluate whether soluble triggering receptor expressed on myeloid cells 1 (sTREM-1) in CSF can serve as a biomarker for the presence of bacterial meningitis and outcome in patients with this disease. DESIGN: Retrospective study of diagnostic accuracy. SETTING AND PATIENTS: CSF was

  2. Residency and Activation of Myeloid Cells During Remodeling of the Prepartum Murine Cervix1

    Science.gov (United States)

    Payne, Kimberly J.; Clyde, Lindsey A.; Weldon, Abby J.; Milford, Terry-Ann; Yellon, Steven M.

    2012-01-01

    ABSTRACT Remodeling of the cervix is a critical early component of parturition and resembles an inflammatory process. Infiltration and activation of myeloid immune cells along with production of proinflammatory mediators and proteolytic enzymes are hypothesized to regulate cervical remodeling as pregnancy nears term. The present study standardized an approach to assess resident populations of immune cells and phenotypic markers of functional activities related to the mechanism of extracellular matrix degradation in the cervix in preparation for birth. Analysis of cells from the dispersed cervix of mice that were nonpregnant or pregnant (Days 15 and 18 postbreeding) by multicolor flow cytometry indicated increased total cell numbers with pregnancy as well as increased numbers of macrophages, the predominant myeloid cell, by Day 18, the day before birth. The number of activated macrophages involved in matrix metalloproteinase induction (CD147) and signaling for matrix adhesion (CD169) significantly increased by the day before birth. Expression of the adhesion markers CD54 and CD11b by macrophages decreased in the cervix by Day 18 versus that on Day 15 or in nonpregnant mice. The census of cells that expressed the migration marker CD62L was unaffected by pregnancy. The data suggest that remodeling of the cervix at term in mice is associated with recruitment and selective activation of macrophages that promote extracellular matrix degradation. Indices of immigration and activities by macrophages may thus serve as markers for local immune cell activity that is critical for ripening of the cervix in the final common mechanism for parturition at term. PMID:22914314

  3. Targeting myeloid cells to the brain using non-myeloablative conditioning.

    Directory of Open Access Journals (Sweden)

    Chotima Böttcher

    Full Text Available Bone marrow-derived cells (BMDCs are able to colonize the central nervous system (CNS at sites of damage. This ability makes BMDCs an ideal cellular vehicle for transferring therapeutic genes/molecules to the CNS. However, conditioning is required for bone marrow-derived myeloid cells to engraft in the brain, which so far has been achieved by total body irradiation (TBI and by chemotherapy (e.g. busulfan treatment. Unfortunately, both regimens massively disturb the host's hematopoietic compartment. Here, we established a conditioning protocol to target myeloid cells to sites of brain damage in mice using non-myeloablative focal head irradiation (HI. This treatment was associated with comparatively low inflammatory responses in the CNS despite cranial radiation doses which are identical to TBI, as revealed by gene expression analysis of cytokines/chemokines such as CCL2, CXCL10, TNF-α and CCL5. HI prior to bone marrow transplantation resulted in much lower levels of blood chimerism defined as the percentage of donor-derived cells in peripheral blood ( 95% or busulfan treatment (> 50%. Nevertheless, HI effectively recruited myeloid cells to the area of motoneuron degeneration in the brainstem within 7 days after facial nerve axotomy. In contrast, no donor-derived cells were detected in the lesioned facial nucleus of busulfan-treated animals up to 2 weeks after transplantation. Our findings suggest that myeloid cells can be targeted to sites of brain damage even in the presence of very low levels of peripheral blood chimerism. We established a novel non-myeloablative conditioning protocol with minimal disturbance of the host's hematopoietic system for targeting BMDCs specifically to areas of pathology in the brain.

  4. Direct conversion of injury-site myeloid cells to fibroblast-like cells of granulation tissue.

    Science.gov (United States)

    Sinha, Mithun; Sen, Chandan K; Singh, Kanhaiya; Das, Amitava; Ghatak, Subhadip; Rhea, Brian; Blackstone, Britani; Powell, Heather M; Khanna, Savita; Roy, Sashwati

    2018-03-05

    Inflammation, following injury, induces cellular plasticity as an inherent component of physiological tissue repair. The dominant fate of wound macrophages is unclear and debated. Here we show that two-thirds of all granulation tissue fibroblasts, otherwise known to be of mesenchymal origin, are derived from myeloid cells which are likely to be wound macrophages. Conversion of myeloid to fibroblast-like cells is impaired in diabetic wounds. In cross-talk between keratinocytes and myeloid cells, miR-21 packaged in extracellular vesicles (EV) is required for cell conversion. EV from wound fluid of healing chronic wound patients is rich in miR-21 and causes cell conversion more effectively compared to that by fluid from non-healing patients. Impaired conversion in diabetic wound tissue is rescued by targeted nanoparticle-based delivery of miR-21 to macrophages. This work introduces a paradigm wherein myeloid cells are recognized as a major source of fibroblast-like cells in the granulation tissue.

  5. Inflammation- and tumor-induced anorexia and weight loss require MyD88 in hematopoietic/myeloid cells but not in brain endothelial or neural cells.

    Science.gov (United States)

    Ruud, Johan; Wilhelms, Daniel Björk; Nilsson, Anna; Eskilsson, Anna; Tang, Yan-Juan; Ströhle, Peter; Caesar, Robert; Schwaninger, Markus; Wunderlich, Thomas; Bäckhed, Fredrik; Engblom, David; Blomqvist, Anders

    2013-05-01

    Loss of appetite is a hallmark of inflammatory diseases. The underlying mechanisms remain undefined, but it is known that myeloid differentiation primary response gene 88 (MyD88), an adaptor protein critical for Toll-like and IL-1 receptor family signaling, is involved. Here we addressed the question of determining in which cells the MyD88 signaling that results in anorexia development occurs by using chimeric mice and animals with cell-specific deletions. We found that MyD88-knockout mice, which are resistant to bacterial lipopolysaccharide (LPS)-induced anorexia, displayed anorexia when transplanted with wild-type bone marrow cells. Furthermore, mice with a targeted deletion of MyD88 in hematopoietic or myeloid cells were largely protected against LPS-induced anorexia and displayed attenuated weight loss, whereas mice with MyD88 deletion in hepatocytes or in neural cells or the cerebrovascular endothelium developed anorexia and weight loss of similar magnitude as wild-type mice. Furthermore, in a model for cancer-induced anorexia-cachexia, deletion of MyD88 in hematopoietic cells attenuated the anorexia and protected against body weight loss. These findings demonstrate that MyD88-dependent signaling within the brain is not required for eliciting inflammation-induced anorexia. Instead, we identify MyD88 signaling in hematopoietic/myeloid cells as a critical component for acute inflammatory-driven anorexia, as well as for chronic anorexia and weight loss associated with malignant disease.

  6. UV light B-mediated inhibition of skin catalase activity promotes Gr-1+ CD11b+ myeloid cell expansion.

    Science.gov (United States)

    Sullivan, Nicholas J; Tober, Kathleen L; Burns, Erin M; Schick, Jonathan S; Riggenbach, Judith A; Mace, Thomas A; Bill, Matthew A; Young, Gregory S; Oberyszyn, Tatiana M; Lesinski, Gregory B

    2012-03-01

    Skin cancer incidence and mortality are higher in men compared with women, but the causes of this sex discrepancy remain largely unknown. UV light exposure induces cutaneous inflammation and neutralizes cutaneous antioxidants. Gr-1(+)CD11b(+) myeloid cells are heterogeneous bone marrow-derived cells that promote inflammation-associated carcinogenesis. Reduced activity of catalase, an antioxidant present in the skin, has been associated with skin carcinogenesis. We used the outbred, immune-competent Skh-1 hairless mouse model of UVB-induced inflammation and non-melanoma skin cancer to further define sex discrepancies in UVB-induced inflammation. Our results demonstrated that male skin had relatively lower baseline catalase activity, which was inhibited following acute UVB exposure in both sexes. Further analysis revealed that skin catalase activity inversely correlated with splenic Gr-1(+)CD11b(+) myeloid cell percentage. Acute UVB exposure induced Gr-1(+)CD11b(+) myeloid cell skin infiltration, which was inhibited to a greater extent in male mice by topical catalase treatment. In chronic UVB studies, we demonstrated that the percentage of splenic Gr-1(+)CD11b(+) myeloid cells was 55% higher in male tumor-bearing mice compared with their female counterparts. Together, our findings indicate that lower skin catalase activity in male mice may at least in part contribute to increased UVB-induced generation of Gr-1(+)CD11b(+) myeloid cells and subsequent skin carcinogenesis.

  7. Dynamics of myeloid cell populations during relapse-preventive immunotherapy in acute myeloid leukemia.

    Science.gov (United States)

    Rydström, Anna; Hallner, Alexander; Aurelius, Johan; Sander, Frida Ewald; Bernson, Elin; Kiffin, Roberta; Thoren, Fredrik Bergh; Hellstrand, Kristoffer; Martner, Anna

    2017-08-01

    Relapse of leukemia in the postchemotherapy phase contributes to the poor prognosis and survival in patients with acute myeloid leukemia (AML). In an international phase IV trial (ClinicalTrials.gov; NCT01347996), 84 patients with AML in first complete remission who had not undergone transplantation received immunotherapy with histamine dihydrochloride (HDC) and low-dose IL-2 with the aim of preventing relapse. The dynamics of myeloid cell counts and expression of activation markers was assessed before and after cycles of immunotherapy and correlated with clinical outcome in terms of relapse risk and survival. During cycles, a pronounced increase in blood eosinophil counts was observed along with a reduction in monocyte and neutrophil counts. A strong reduction of blood monocyte counts during the first HDC/IL-2 treatment cycle predicted leukemia-free survival. The HDC component of the immunotherapy exerts agonist activity at histamine type 2 receptors (H2Rs) that are expressed by myeloid cells. It was observed that the density of H 2 R expression in blood monocytes increased during cycles of immunotherapy and that high monocyte H 2 R expression implied reduced relapse risk and improved overall survival. Several other activation markers, including HLA-DR, CD86, and CD40, were induced in monocytes and dendritic cells during immunotherapy but did not predict clinical outcome. In addition, expression of HLA-ABC increased in all myeloid populations during therapy. A low expression of HLA-ABC was associated with reduced relapse risk. These results suggest that aspects of myeloid cell biology may impact clinical benefit of relapse-preventive immunotherapy in AML. © Society for Leukocyte Biology.

  8. Quantitation of specific myeloid cells in rat bone marrow measured by in vitro /sup 35/S-sulphate incorporation

    Energy Technology Data Exchange (ETDEWEB)

    Wright, A F; Rose, M S

    1984-08-01

    A biochemical measurement which can be used for quantitation of specific early myeloid cells in rat bone marrow has been developed. This measurement consists of a rapid, simple assay for the in vitro quantitation of /sup 35/S-sulfate incorporation into rat bone marrow cells. Incubation of bone marrow cells with /sup 35/S-sulfate led to a time-dependent increase in radioactivity obtained in perchloric acid insoluble fractions of bone marrow cell suspensions. This incorporation was inhibited by cyanide and puromycin. Autoradiography has demonstrated the radiolabel to be specifically associated with immature cells of the myeloid series. The cells most active in this respect were eosinophils. When rats were treated with endotoxin, the rate of /sup 35/S-sulfate incorporation was increased. Cell number measurements, using conventional histopathology and a Coulter Counter, demonstrated that endotoxin caused an initial release of mature granulocytes from the bone marrow. The regeneration of this mature population in the marrow was rapid, and was characterized by an increase in the number of immature cells and a concomitant increase in the rate of /sup 35/S-sulfate incorporation measured in preparations of bone marrow cells in vitro. Furthermore, this response to endotoxin has demonstrated that Coulter Counting techniques can be used to distinguish specific populations of cells (e.g. mature granulocytes) within the bone marrow.

  9. Generation of Human Immunosuppressive Myeloid Cell Populations in Human Interleukin-6 Transgenic NOG Mice

    Directory of Open Access Journals (Sweden)

    Asami Hanazawa

    2018-02-01

    Full Text Available The tumor microenvironment contains unique immune cells, termed myeloid-derived suppressor cells (MDSCs, and tumor-associated macrophages (TAMs that suppress host anti-tumor immunity and promote tumor angiogenesis and metastasis. Although these cells are considered a key target of cancer immune therapy, in vivo animal models allowing differentiation of human immunosuppressive myeloid cells have yet to be established, hampering the development of novel cancer therapies. In this study, we established a novel humanized transgenic (Tg mouse strain, human interleukin (hIL-6-expressing NOG mice (NOG-hIL-6 transgenic mice. After transplantation of human hematopoietic stem cells (HSCs, the HSC-transplanted NOG-hIL-6 Tg mice (HSC-NOG-hIL-6 Tg mice showed enhanced human monocyte/macrophage differentiation. A significant number of human monocytes were negative for HLA-DR expression and resembled immature myeloid cells in the spleen and peripheral blood from HSC-NOG-hIL-6 Tg mice, but not from HSC-NOG non-Tg mice. Engraftment of HSC4 cells, a human head and neck squamous cell carcinoma-derived cell line producing various factors including IL-6, IL-1β, macrophage colony-stimulating factor (M-CSF, and vascular endothelial growth factor (VEGF, into HSC-NOG-hIL-6 Tg mice induced a significant number of TAM-like cells, but few were induced in HSC-NOG non-Tg mice. The tumor-infiltrating macrophages in HSC-NOG-hIL-6 Tg mice expressed a high level of CD163, a marker of immunoregulatory myeloid cells, and produced immunosuppressive molecules such as arginase-1 (Arg-1, IL-10, and VEGF. Such cells from HSC-NOG-hIL-6 Tg mice, but not HSC-NOG non-Tg mice, suppressed human T cell proliferation in response to antigen stimulation in in vitro cultures. These results suggest that functional human TAMs can be developed in NOG-hIL-6 Tg mice. This mouse model will contribute to the development of novel cancer immune therapies targeting immunoregulatory

  10. Radiation response of mouse lymphoid and myeloid cell lines. Pt. 1

    International Nuclear Information System (INIS)

    Radford, I.R.

    1994-01-01

    The sensitivity of 10 mouse lymphoid or myeloid cell lines to γ-ray- and DNA-associated 125 I-decay-induced clonogenic cell killing have been compared with their rate of loss of viability (membrane integrity) and with their putative cell type of origin. The increased sensitivity of haematopoietic cell lines to killing by DNA dsb may be related to their mode of death (apoptosis versus necrosis). Mode of cell death may thus be an important factor in determining the 'inherent radiosensitivity' of normal cells/tissues. Haematopoietic cell lines that undergo rapid interphase apoptotic death showed extreme sensitivity to DNA dsb. (author)

  11. Colony stimulating factor 1 receptor inhibition delays recurrence of glioblastoma after radiation by altering myeloid cell recruitment and polarization

    Science.gov (United States)

    Stafford, Jason H.; Hirai, Takahisa; Deng, Lei; Chernikova, Sophia B.; Urata, Kimiko; West, Brian L.; Brown, J. Martin

    2016-01-01

    Background Glioblastoma (GBM) may initially respond to treatment with ionizing radiation (IR), but the prognosis remains extremely poor because the tumors invariably recur. Using animal models, we previously showed that inhibiting stromal cell–derived factor 1 signaling can prevent or delay GBM recurrence by blocking IR-induced recruitment of myeloid cells, specifically monocytes that give rise to tumor-associated macrophages. The present study was aimed at determining if inhibiting colony stimulating factor 1 (CSF-1) signaling could be used as an alternative strategy to target pro-tumorigenic myeloid cells recruited to irradiated GBM. Methods To inhibit CSF-1 signaling in myeloid cells, we used PLX3397, a small molecule that potently inhibits the tyrosine kinase activity of the CSF-1 receptor (CSF-1R). Combined IR and PLX3397 therapy was compared with IR alone using 2 different human GBM intracranial xenograft models. Results GBM xenografts treated with IR upregulated CSF-1R ligand expression and increased the number of CD11b+ myeloid-derived cells in the tumors. Treatment with PLX3397 both depleted CD11b+ cells and potentiated the response of the intracranial tumors to IR. Median survival was significantly longer for mice receiving combined therapy versus IR alone. Analysis of myeloid cell differentiation markers indicated that CSF-1R inhibition prevented IR-recruited monocyte cells from differentiating into immunosuppressive, pro-angiogenic tumor-associated macrophages. Conclusion CSF-1R inhibition may be a promising strategy to improve GBM response to radiotherapy. PMID:26538619

  12. FcγRIIb on myeloid cells rather than on B cells protects from collagen-induced arthritis.

    Science.gov (United States)

    Yilmaz-Elis, A Seda; Ramirez, Javier Martin; Asmawidjaja, Patrick; van der Kaa, Jos; Mus, Anne-Marie; Brem, Maarten D; Claassens, Jill W C; Breukel, Cor; Brouwers, Conny; Mangsbo, Sara M; Boross, Peter; Lubberts, Erik; Verbeek, J Sjef

    2014-06-15

    Extensive analysis of a variety of arthritis models in germline KO mice has revealed that all four receptors for the Fc part of IgG (FcγR) play a role in the disease process. However, their precise cell type-specific contribution is still unclear. In this study, we analyzed the specific role of the inhibiting FcγRIIb on B lymphocytes (using CD19Cre mice) and in the myeloid cell compartment (using C/EBPαCre mice) in the development of arthritis induced by immunization with either bovine or chicken collagen type II. Despite their comparable anti-mouse collagen autoantibody titers, full FcγRIIb knockout (KO), but not B cell-specific FcγRIIb KO, mice showed a significantly increased incidence and severity of disease compared with wild-type control mice when immunized with bovine collagen. When immunized with chicken collagen, disease incidence was significantly increased in pan-myeloid and full FcγRIIb KO mice, but not in B cell-specific KO mice, whereas disease severity was only significantly increased in full FcγRIIb KO mice compared with incidence and severity in wild-type control mice. We conclude that, although anti-mouse collagen autoantibodies are a prerequisite for the development of collagen-induced arthritis, their presence is insufficient for disease development. FcγRIIb on myeloid effector cells, as a modulator of the threshold for downstream Ab effector pathways, plays a dominant role in the susceptibility to collagen-induced arthritis, whereas FcγRIIb on B cells, as a regulator of Ab production, has a minor effect on disease susceptibility. Copyright © 2014 by The American Association of Immunologists, Inc.

  13. Retroviruses As Myeloid Cell Riders: What Natural Human Siglec-1 “Knockouts” Tell Us About Pathogenesis

    Directory of Open Access Journals (Sweden)

    Javier Martinez-Picado

    2017-11-01

    Full Text Available Myeloid cells initiate immune responses and are crucial to control infections. In the case of retroviruses, however, myeloid cells also promote pathogenesis by enabling viral dissemination; a process extensively studied in vitro using human immunodeficiency virus type 1 (HIV-1. This viral hijacking mechanism does not rely on productive myeloid cell infection but requires HIV-1 capture via Siglec-1/CD169, a receptor expressed on myeloid cells that facilitates the infection of bystander target cells. Murine retroviruses are also recognized by Siglec-1, and this interaction is required for robust retroviral infection in vivo. Yet, the relative contribution of Siglec-1-mediated viral dissemination to HIV-1 disease progression remains unclear. The identification of human null individuals lacking working copies of a particular gene enables studying how this loss affects disease progression. Moreover, it can reveal novel antiviral targets whose blockade might be therapeutically effective and safe, since finding null individuals in natura uncovers dispensable functions. We previously described a loss-of-function variant in SIGLEC-1. Analysis of a large cohort of HIV-1-infected individuals identified homozygous and heterozygous subjects, whose cells were functionally null or partially defective for Siglec-1 activity in HIV-1 capture and transmission ex vivo. Nonetheless, analysis of the effect of Siglec-1 truncation on progression to AIDS was not conclusive due to the limited cohort size, the lack of complete clinical records, and the restriction to study only off-therapy periods. Here, we review how the study of loss-of-function variants might serve to illuminate the role of myeloid cells in viral pathogenesis in vivo and the challenges ahead.

  14. Triggering receptor expressed on myeloid cells 2 (TREM2): a potential therapeutic target for Alzheimer disease?

    Science.gov (United States)

    Deming, Yuetiva; Li, Zeran; Benitez, Bruno A; Cruchaga, Carlos

    2018-06-20

    There are currently no effective therapeutics for Alzheimer disease (AD). Clinical trials targeting amyloid beta thus far have shown very little benefit and only in the earliest stages of disease. These limitations have driven research to identify alternative therapeutic targets, one of the most promising is the triggering receptor expressed on myeloid cells 2 (TREM2). Areas covered: Here, we review the literature to-date and discuss the potentials and pitfalls for targeting TREM2 as a potential therapeutic for AD. We focus on research in animal and cell models for AD and central nervous system injury models which may help in understanding the role of TREM2 in disease. Expert opinion: Studies suggest TREM2 plays a key role in AD pathology; however, results have been conflicting about whether TREM2 is beneficial or harmful. More research is necessary before designing TREM2-targeting therapies. Successful therapeutics will most likely be administered early in disease.

  15. Myeloid cells in circulation and tumor microenvironment of breast cancer patients.

    Science.gov (United States)

    Toor, Salman M; Syed Khaja, Azharuddin Sajid; El Salhat, Haytham; Faour, Issam; Kanbar, Jihad; Quadri, Asif A; Albashir, Mohamed; Elkord, Eyad

    2017-06-01

    Pathological conditions including cancers lead to accumulation of a morphological mixture of highly immunosuppressive cells termed as myeloid-derived suppressor cells (MDSC). The lack of conclusive markers to identify human MDSC, due to their heterogeneous nature and close phenotypical and functional proximity with other cell subsets, made it challenging to identify these cells. Nevertheless, expansion of MDSC has been reported in periphery and tumor microenvironment of various cancers. The majority of studies on breast cancers were performed on murine models and hence limited literature is available on the relation of MDSC accumulation with clinical settings in breast cancer patients. The aim of this study was to investigate levels and phenotypes of myeloid cells in peripheral blood (n = 23) and tumor microenvironment of primary breast cancer patients (n = 7), compared with blood from healthy donors (n = 21) and paired non-tumor normal breast tissues from the same patients (n = 7). Using multicolor flow cytometric assays, we found that breast cancer patients had significantly higher levels of tumor-infiltrating myeloid cells, which comprised of granulocytes (P = 0.022) and immature cells that lack the expression of markers for fully differentiated monocytes or granulocytes (P = 0.016). Importantly, this expansion was not reflected in the peripheral blood. The immunosuppressive potential of these cells was confirmed by expression of Arginase 1 (ARG1), which is pivotal for T-cell suppression. These findings are important for developing therapeutic modalities to target mechanisms employed by immunosuppressive cells that generate an immune-permissive environment for the progression of cancer.

  16. Multiple helminth infection of the skin causes lymphocyte hypo-responsiveness mediated by Th2 conditioning of dermal myeloid cells.

    Directory of Open Access Journals (Sweden)

    Peter C Cook

    2011-03-01

    Full Text Available Infection of the mammalian host by schistosome larvae occurs via the skin, although nothing is known about the development of immune responses to multiple exposures of schistosome larvae, and/or their excretory/secretory (E/S products. Here, we show that multiple (4x exposures, prior to the onset of egg laying by adult worms, modulate the skin immune response and induce CD4(+ cell hypo-responsiveness in the draining lymph node, and even modulate the formation of hepatic egg-induced granulomas. Compared to mice exposed to a single infection (1x, dermal cells from multiply infected mice (4x, were less able to support lymph node cell proliferation. Analysis of dermal cells showed that the most abundant in 4x mice were eosinophils (F4/80(+MHC-II(-, but they did not impact the ability of antigen presenting cells (APC to support lymphocyte proliferation to parasite antigen in vitro. However, two other cell populations from the dermal site of infection appear to have a critical role. The first comprises arginase-1(+, Ym-1(+ alternatively activated macrophage-like cells, and the second are functionally compromised MHC-II(hi cells. Through the administration of exogenous IL-12 to multiply infected mice, we show that these suppressive myeloid cell phenotypes form as a consequence of events in the skin, most notably an enrichment of IL-4 and IL-13, likely resulting from an influx of RELMα-expressing eosinophils. We further illustrate that the development of these suppressive dermal cells is dependent upon IL-4Rα signalling. The development of immune hypo-responsiveness to schistosome larvae and their effect on the subsequent response to the immunopathogenic egg is important in appreciating how immune responses to helminth infections are modulated by repeated exposure to the infective early stages of development.

  17. Temporal Regulation of Natural Killer T Cell Interferon Gamma Responses by β-Catenin-Dependent and -Independent Wnt Signaling.

    Science.gov (United States)

    Kling, Jessica C; Jordan, Margaret A; Pitt, Lauren A; Meiners, Jana; Thanh-Tran, Thao; Tran, Le Son; Nguyen, Tam T K; Mittal, Deepak; Villani, Rehan; Steptoe, Raymond J; Khosrotehrani, Kiarash; Berzins, Stuart P; Baxter, Alan G; Godfrey, Dale I; Blumenthal, Antje

    2018-01-01

    Natural killer T (NKT) cells are prominent innate-like lymphocytes in the liver with critical roles in immune responses during infection, cancer, and autoimmunity. Interferon gamma (IFN-γ) and IL-4 are key cytokines rapidly produced by NKT cells upon recognition of glycolipid antigens presented by antigen-presenting cells (APCs). It has previously been reported that the transcriptional coactivator β-catenin regulates NKT cell differentiation and functionally biases NKT cell responses toward IL-4, at the expense of IFN-γ production. β-Catenin is not only a central effector of Wnt signaling but also contributes to other signaling networks. It is currently unknown whether Wnt ligands regulate NKT cell functions. We thus investigated how Wnt ligands and β-catenin activity shape liver NKT cell functions in vivo in response to the glycolipid antigen, α-galactosylceramide (α-GalCer) using a mouse model. Pharmacologic targeting of β-catenin activity with ICG001, as well as myeloid-specific genetic ablation of Wntless (Wls) , to specifically target Wnt protein release by APCs, enhanced early IFN-γ responses. By contrast, within several hours of α-GalCer challenge, myeloid-specific Wls deficiency, as well as pharmacologic targeting of Wnt release using the small molecule inhibitor IWP-2 impaired α-GalCer-induced IFN-γ responses, independent of β-catenin activity. These data suggest that myeloid cell-derived Wnt ligands drive early Wnt/β-catenin signaling that curbs IFN-γ responses, but that, subsequently, Wnt ligands sustain IFN-γ expression independent of β-catenin activity. Our analyses in ICG001-treated mice confirmed a role for β-catenin activity in driving early IL-4 responses by liver NKT cells. However, neither pharmacologic nor genetic perturbation of Wnt production affected the IL-4 response, suggesting that IL-4 production by NKT cells in response to α-GalCer is not driven by released Wnt ligands. Collectively, these data reveal complex temporal

  18. Temporal Regulation of Natural Killer T Cell Interferon Gamma Responses by β-Catenin-Dependent and -Independent Wnt Signaling

    Directory of Open Access Journals (Sweden)

    Jessica C. Kling

    2018-03-01

    Full Text Available Natural killer T (NKT cells are prominent innate-like lymphocytes in the liver with critical roles in immune responses during infection, cancer, and autoimmunity. Interferon gamma (IFN-γ and IL-4 are key cytokines rapidly produced by NKT cells upon recognition of glycolipid antigens presented by antigen-presenting cells (APCs. It has previously been reported that the transcriptional coactivator β-catenin regulates NKT cell differentiation and functionally biases NKT cell responses toward IL-4, at the expense of IFN-γ production. β-Catenin is not only a central effector of Wnt signaling but also contributes to other signaling networks. It is currently unknown whether Wnt ligands regulate NKT cell functions. We thus investigated how Wnt ligands and β-catenin activity shape liver NKT cell functions in vivo in response to the glycolipid antigen, α-galactosylceramide (α-GalCer using a mouse model. Pharmacologic targeting of β-catenin activity with ICG001, as well as myeloid-specific genetic ablation of Wntless (Wls, to specifically target Wnt protein release by APCs, enhanced early IFN-γ responses. By contrast, within several hours of α-GalCer challenge, myeloid-specific Wls deficiency, as well as pharmacologic targeting of Wnt release using the small molecule inhibitor IWP-2 impaired α-GalCer-induced IFN-γ responses, independent of β-catenin activity. These data suggest that myeloid cell-derived Wnt ligands drive early Wnt/β-catenin signaling that curbs IFN-γ responses, but that, subsequently, Wnt ligands sustain IFN-γ expression independent of β-catenin activity. Our analyses in ICG001-treated mice confirmed a role for β-catenin activity in driving early IL-4 responses by liver NKT cells. However, neither pharmacologic nor genetic perturbation of Wnt production affected the IL-4 response, suggesting that IL-4 production by NKT cells in response to α-GalCer is not driven by released Wnt ligands. Collectively, these data reveal

  19. SAMHD1 restricts HIV-1 replication and regulates interferon production in mouse myeloid cells.

    Directory of Open Access Journals (Sweden)

    Ruonan Zhang

    Full Text Available SAMHD1 restricts the replication of HIV-1 and other retroviruses in human myeloid and resting CD4(+ T cells and that is counteracted in SIV and HIV-2 by the Vpx accessory protein. The protein is a phosphohydrolase that lowers the concentration of deoxynucleoside triphosphates (dNTP, blocking reverse transcription of the viral RNA genome. Polymorphisms in the gene encoding SAMHD1 are associated with Aicardi-Goutières Syndrome, a neurological disorder characterized by increased type-I interferon production. SAMHD1 is conserved in mammals but its role in restricting virus replication and controlling interferon production in non-primate species is not well understood. We show that SAMHD1 is catalytically active and expressed at high levels in mouse spleen, lymph nodes, thymus and lung. siRNA knock-down of SAMHD1 in bone marrow-derived macrophages increased their susceptibility to HIV-1 infection. shRNA knock-down of SAMHD1 in the murine monocytic cell-line RAW264.7 increased its susceptibility to HIV-1 and murine leukemia virus and increased the levels of the dNTP pool. In addition, SAMHD1 knock-down in RAW264.7 cells induced the production of type-I interferon and several interferon-stimulated genes, modeling the situation in Aicardi-Goutières Syndrome. Our findings suggest that the role of SAMHD1 in restricting viruses is conserved in the mouse. The RAW264.7 cell-line serves as a useful tool to study the antiviral and innate immune response functions of SAMHD1.

  20. Path dependence and independent utility regulation

    DEFF Research Database (Denmark)

    Ibsen, Christian Lyhne; Skovgaard Poulsen, Lauge

    2007-01-01

    The establishment of the Danish independent regulatory authorities for the energy and telecommunications sectors was based upon EU directives as part of their liberalisation process. Following the concepts of transaction costs and path dependency this article analyses differences in independence...... between the two authorities - the Danish Energy Regulatory Authority (Energitilsynet) and the National IT and Telecommunications Agency (IT- og Telestyrelsen) respectively. We find that the state's negligible interest in the energy sector until the 1970s formed the basis for strong energy companies...

  1. Myeloid-Cell-Derived VEGF Maintains Brain Glucose Uptake and Limits Cognitive Impairment in Obesity.

    Science.gov (United States)

    Jais, Alexander; Solas, Maite; Backes, Heiko; Chaurasia, Bhagirath; Kleinridders, André; Theurich, Sebastian; Mauer, Jan; Steculorum, Sophie M; Hampel, Brigitte; Goldau, Julia; Alber, Jens; Förster, Carola Y; Eming, Sabine A; Schwaninger, Markus; Ferrara, Napoleone; Karsenty, Gerard; Brüning, Jens C

    2016-05-05

    High-fat diet (HFD) feeding induces rapid reprogramming of systemic metabolism. Here, we demonstrate that HFD feeding of mice downregulates glucose transporter (GLUT)-1 expression in blood-brain barrier (BBB) vascular endothelial cells (BECs) and reduces brain glucose uptake. Upon prolonged HFD feeding, GLUT1 expression is restored, which is paralleled by increased expression of vascular endothelial growth factor (VEGF) in macrophages at the BBB. In turn, inducible reduction of GLUT1 expression specifically in BECs reduces brain glucose uptake and increases VEGF serum concentrations in lean mice. Conversely, myeloid-cell-specific deletion of VEGF in VEGF(Δmyel) mice impairs BBB-GLUT1 expression, brain glucose uptake, and memory formation in obese, but not in lean mice. Moreover, obese VEGF(Δmyel) mice exhibit exaggerated progression of cognitive decline and neuroinflammation on an Alzheimer's disease background. These experiments reveal that transient, HFD-elicited reduction of brain glucose uptake initiates a compensatory increase of VEGF production and assign obesity-associated macrophage activation a homeostatic role to restore cerebral glucose metabolism, preserve cognitive function, and limit neurodegeneration in obesity. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Streptococci Engage TLR13 on Myeloid Cells in a Site-Specific Fashion.

    Science.gov (United States)

    Kolter, Julia; Feuerstein, Reinhild; Spoeri, Evelyne; Gharun, Kourosh; Elling, Roland; Trieu-Cuot, Patrick; Goldmann, Tobias; Waskow, Claudia; Chen, Zhijian J; Kirschning, Carsten J; Deshmukh, Sachin D; Henneke, Philipp

    2016-03-15

    Streptococci are common human colonizers with a species-specific mucocutaneous distribution. At the same time, they are among the most important and most virulent invasive bacterial pathogens. Thus, site-specific cellular innate immunity, which is predominantly executed by resident and invading myeloid cells, has to be adapted with respect to streptococcal sensing, handling, and response. In this article, we show that TLR13 is the critical mouse macrophage (MΦ) receptor in the response to group B Streptococcus, both in bone marrow-derived MΦs and in mature tissue MΦs, such as those residing in the lamina propria of the colon and the dermis, as well as in microglia. In contrast, TLR13 and its chaperone UNC-93B are dispensable for a potent cytokine response of blood monocytes to group B Streptococcus, although monocytes serve as the key progenitors of intestinal and dermal MΦs. Furthermore, a specific role for TLR13 with respect to MΦ function is supported by the response to staphylococci, where TLR13 and UNC-93B limit the cytokine response in bone marrow-derived MΦs and microglia, but not in dermal MΦs. In summary, TLR13 is a critical and site-specific receptor in the single MΦ response to β-hemolytic streptococci. Copyright © 2016 by The American Association of Immunologists, Inc.

  3. Soluble Triggering Receptor Expressed on Myeloid Cells-1 as a Novel Marker for Abdominal Sepsis.

    Science.gov (United States)

    Song, Xiaofei; Song, Yucheng; Zhang, Xuedong; Xue, Huanzhou

    2017-07-01

    The aim of the study was to investigate the concentration and diagnostic significance of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) in acute abdominal conditions. Plasma specimens were obtained from 68 patients with abdominal sepsis, 60 patients with systemic inflammatory response syndrome (SIRS), and 60 healthy individuals. The sepsis group was divided into the survival and death groups according to the 28-d outcome. Plasma sTREM-1, procalcitonin (PCT), C-reactive protein (CRP), and white blood cell (WBC) count were measured. A receiver operating characteristic curve (ROC) was used to compare the diagnostic values of sTREM-1, PCT, CRP, and WBC count. In addition, the correlation between plasma sTREM-1 and the Acute Physiology and Chronic Health Evaluation (APACHE) II score in the sepsis group was assessed by Spearman correlation analysis. The plasma concentration of sTREM-1 in the sepsis group was significantly higher than that in the SIRS and healthy groups (both p sepsis vs. SIRS showed that the area under the curve of sTREM-1 (0.82) was greater than that of PCT (0.77), CRP (0.72), and WBC count (0.70). Additionally, in the sepsis group, the plasma sTREM-1 concentration correlated positively with the APACHE II score (r = 0.41; p sepsis.

  4. Dependence regulation in newlywed couples: A prospective examination.

    Science.gov (United States)

    Derrick, Jaye L; Leonard, Kenneth E; Homish, Gregory G

    2012-12-01

    According to the Risk Regulation Model (Murray, S. L., Holmes, J. G., & Collins, N. L. (2006). Optimizing assurance: The risk regulation system in relationships. Psychological Bulletin, 132 , 641-666), people need to trust in their partner's regard before they risk interdependence. The current study prospectively examines the association between perceived regard and levels of dependence in newlywed couples over nine years of marriage. Analyses demonstrate that changes in perceived regard predict levels of dependence, changes in dependence do not predict perceived regard, and alternative explanations cannot account for these effects. Further, changes in perceived regard prospectively predict divorce, and levels of dependence mediate this association. Results are discussed in terms of the dependence regulation component of the Risk Regulation Model.

  5. Role of endocannabinoids in regulating drug dependence

    Directory of Open Access Journals (Sweden)

    Daniela Parolaro

    2007-01-01

    Full Text Available Daniela Parolaro, Daniela Vigano’, Natalia Realini, Tiziana RubinoNeuroscience Center, DBSF, University of Insubria, Busto Arsizio, ItalyAbstract: This review will discuss the latest knowledge of how the endocannabinoid system might be involved in treating addiction to the most common illicit drugs. Experimental models are providing increasing evidence for the pharmacological management of endocannabinoid signaling not only to block the direct reinforcing effects of cannabis, opioids, nicotine and ethanol, but also for preventing relapse to the various drugs of abuse, including opioids, cocaine, nicotine, alcohol and metamphetamine. Preclinical and clinical studies suggest that the endocannabinoid system can be manipulated by the CB1 receptor antagonist SR141716A, that might constitute a new generation of compounds for treating addiction across different classes of abused drugs.Keywords: Endocannabinoids, drug dependence, opioids, nicotine, alcohol, psychostimulants

  6. Cardiac-Restricted IGF-1Ea Overexpression Reduces the Early Accumulation of Inflammatory Myeloid Cells and Mediates Expression of Extracellular Matrix Remodelling Genes after Myocardial Infarction

    Directory of Open Access Journals (Sweden)

    Enrique Gallego-Colon

    2015-01-01

    Full Text Available Strategies to limit damage and improve repair after myocardial infarct remain a major therapeutic goal in cardiology. Our previous studies have shown that constitutive expression of a locally acting insulin-like growth factor-1 Ea (IGF-1Ea propeptide promotes functional restoration after cardiac injury associated with decreased scar formation. In the current study, we investigated the underlying molecular and cellular mechanisms behind the enhanced functional recovery. We observed improved cardiac function in mice overexpressing cardiac-specific IGF-1Ea as early as day 7 after myocardial infarction. Analysis of gene transcription revealed that supplemental IGF-1Ea regulated expression of key metalloproteinases (MMP-2 and MMP-9, their inhibitors (TIMP-1 and TIMP-2, and collagen types (Col 1α1 and Col 1α3 in the first week after injury. Infiltration of inflammatory cells, which direct the remodelling process, was also altered; in particular there was a notable reduction in inflammatory Ly6C+ monocytes at day 3 and an increase in anti-inflammatory CD206+ macrophages at day 7. Taken together, these results indicate that the IGF-1Ea transgene shifts the balance of innate immune cell populations early after infarction, favouring a reduction in inflammatory myeloid cells. This correlates with reduced extracellular matrix remodelling and changes in collagen composition that may confer enhanced scar elasticity and improved cardiac function.

  7. A comparative study of self-regulation in substance dependent and non-dependent individuals.

    Science.gov (United States)

    Bakhshani, Nour Mohammad; Hosseinbor, Mohsen

    2013-08-05

    Several factors influence the beginning and maintenance of substance use. The purpose of this study was to examine as well as to compare 'self-regulation' in both substance dependent and non-substance dependent individuals. In a cross-sectional study 228 (118 substance dependent and 110 with no history of using substance) participants aged 16-55 were recruited. All of the participants were asked to complete the Self-Regulation Inventory (SRI-25) and a demographic characteristics data checklist. Data was analyzed using descriptive statistics (frequency, mean and standard deviation) and the t-test. The results showed significant differences between substance dependent and non- substance dependent groups in all the scales of the self-regulation inventory including positive actions, controllability, expression of feelings and needs, assertiveness, and well-being seeking (p<0.01). Self-regulation and self-control skills in drug dependent individuals are lower than those without substance dependence individuals. It is concluded that substance use may related to a deficiency in self-control and regulation of feelings. Therefore, for prevention and treatment of substance dependence disorder, it is necessary to work out and exploit strategies that include the improvement of self-regulation.

  8. Hepatic ischemia and reperfusion injury in the absence of myeloid cell-derived COX-2 in mice.

    Directory of Open Access Journals (Sweden)

    Sergio Duarte

    Full Text Available Cyclooxygenase-2 (COX-2 is a mediator of hepatic ischemia and reperfusion injury (IRI. While both global COX-2 deletion and pharmacologic COX-2 inhibition ameliorate liver IRI, the clinical use of COX-2 inhibitors has been linked to increased risks of heart attack and stroke. Therefore, a better understanding of the role of COX-2 in different cell types may lead to improved therapeutic strategies for hepatic IRI. Macrophages of myeloid origin are currently considered to be important sources of the COX-2 in damaged livers. Here, we used a Cox-2flox conditional knockout mouse (COX-2-M/-M to examine the function of COX-2 expression in myeloid cells during liver IRI. COX-2-M/-M mice and their WT control littermates were subjected to partial liver ischemia followed by reperfusion. COX-2-M/-M macrophages did not express COX-2 upon lipopolysaccharide stimulation and COX-2-M/-M livers showed reduced levels of COX-2 protein post-IRI. Nevertheless, selective deletion of myeloid cell-derived COX-2 failed to ameliorate liver IRI; serum transaminases and histology were comparable in both COX-2-M/-M and WT mice. COX-2-M/-M livers, like WT livers, developed extensive necrosis, vascular congestion, leukocyte infiltration and matrix metalloproteinase-9 (MMP-9 expression post-reperfusion. In addition, myeloid COX-2 deletion led to a transient increase in IL-6 levels after hepatic reperfusion, when compared to controls. Administration of celecoxib, a selective COX-2 inhibitor, resulted in significantly improved liver function and histology in both COX-2-M/-M and WT mice post-reperfusion, providing evidence that COX-2-mediated liver IRI is caused by COX-2 derived from a source(s other than myeloid cells. In conclusion, these results support the view that myeloid COX-2, including myeloid-macrophage COX-2, is not responsible for the hepatic IRI phenotype.

  9. Kinetics of rebounding of lymphoid and myeloid cells in mouse peripheral blood, spleen and bone marrow after treatment with cyclophosphamide

    OpenAIRE

    Salem, Mohamed L.; Al-Khami, Amir A.; El-Nagaar, Sabry A.; Zidan, Abdel-Aziz A.; Al-Sharkawi, Ismail M.; Díaz-Montero, C. Marcela; Cole, David J.

    2012-01-01

    Recently, we showed that post cyclophosphamide (CTX) microenvironment benefits the function of transferred T cells. Analysis of the kinetics of cellular recovery after CTX treatment showed that a single 4 mg/mouse CTX treatment decreased the absolute number of leukocytes in the peripheral blood (PBL) at days 3-15, and in the spleen and bone marrow (BM) at days 3-6. The absolute numbers of CD11c+CD11b− and CD11c+CD11b+ dendritic cells (DCs), CD11b+ and Ly6G+ myeloid cells, T and B cells, CD4+C...

  10. Gamma Delta T-Cells Regulate Inflammatory Cell Infiltration of the Lung after Trauma-Hemorrhage

    Science.gov (United States)

    2015-06-01

    suggesting a role for this T- cell subset in both innate and acquired immunity (7, 8). Studies have shown that +% T cells are required for both controlled...increased infiltration of both lymphoid and myeloid cells in WT mice after TH-induced ALI. In parallel to +% T cells , myeloid cells (i.e., monocytes...GAMMA DELTA T CELLS REGULATE INFLAMMATORY CELL INFILTRATION OF THE LUNG AFTER TRAUMA-HEMORRHAGE Meenakshi Rani,* Qiong Zhang,* Richard F. Oppeltz

  11. Exogenous fatty acids and niacin on acute prostaglandin D2 production in human myeloid cells.

    Science.gov (United States)

    Montserrat-de la Paz, Sergio; Bermudez, Beatriz; Lopez, Sergio; Naranjo, Maria C; Romero, Yolanda; Bando-Hidalgo, Maria J; Abia, Rocio; Muriana, Francisco J G

    2017-01-01

    Niacin activates HCA 2 receptor that results in the release of PGD 2 . However, little is known on PGD 2 -producing cells and the role of fatty acids. Notably M-CSF macrophages exhibited a timely dependent PGD 2 production upon niacin challenge. Short pretreatment of M-CSF macrophages with autologous postprandial TRLs induced the down-regulation of HCA 2 gene and up-regulation of genes encoding COX1 and COX2 enzymes in a fatty acid-dependent manner. These effects were paralleled by a higher PGD 2 production with postprandial TRL-SFAs. The niacin-mediated transcriptional activity of all genes involved in PGD 2 biosynthesis was desensitized in a time-dependent manner by postprandial TRLs, leading to a decreased PGD 2 release. In vivo, the net excursions of PGD 2 in plasma followed similar fatty acid-dependent patterns as those found for PGD 2 release in vitro. The predominant fatty acid class in the diet acutely modulates PGD 2 biosynthetic pathway both in vitro and in vivo. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Control of Both Myeloid Cell Infiltration and Angiogenesis by CCR1 Promotes Liver Cancer Metastasis Development in Mice

    Directory of Open Access Journals (Sweden)

    Mathieu Paul Rodero

    2013-06-01

    Full Text Available Expression of the CC chemokine receptor 1 (CCR1 by tumor cells has been associated with protumoral activity; however, its role in nontumoral cells during tumor development remains elusive. Here, we investigated the role of CCR1 deletion on stromal and hematopoietic cells in a liver metastasis tumor model. Metastasis development was strongly impaired in CCR1-deficient mice compared to control mice and was associated with reduced liver monocyte infiltration. To decipher the role of myeloid cells, sublethally irradiated mice were reconstituted with CCR1-deficient bone marrow (BM and showed better survival rates than the control reconstituted mice. These results point toward the involvement of CCR1 myeloid cell infiltration in the promotion of tumor burden. In addition, survival rates were extended in CCR1-deficient mice receiving either control or CCR1-deficient BM, indicating that host CCR1 expression on nonhematopoietic cells also supports tumor growth. Finally, we found defective tumor-induced neoangiogenesis (in vitro and in vivo in CCR1-deficient mice. Overall, our results indicate that CCR1 expression by both hematopoietic and nonhematopoietic cells favors tumor aggressiveness. We propose CCR1 as a potential therapeutical target for liver metastasis therapy.

  13. Intravenous administration of bone marrow-derived multipotent mesenchymal stromal cells enhances the recruitment of CD11b{sup +} myeloid cells to the lungs and facilitates B16-F10 melanoma colonization

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Lucas E.B., E-mail: lucasebsouza@usp.br [Department of Clinical Medicine, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil); Hemotherapy Center of Ribeirão Preto, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil); Almeida, Danilo C., E-mail: gudaalmeida@gmail.com [Department of Medicine – Nephrology, Laboratory of Clinical and Experimental Immunology, Federal University of São Paulo, São Paulo, SP (Brazil); Yaochite, Juliana N.U., E-mail: ueda.juliana@gmail.com [Department of Biochemistry and Immunology, Basic and Applied Immunology Program, School of Medicine of Ribeirão Preto, University of São Paulo (Brazil); Covas, Dimas T., E-mail: dimas@fmrp.usp.br [Department of Clinical Medicine, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil); Hemotherapy Center of Ribeirão Preto, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil); Fontes, Aparecida M., E-mail: aparecidamfontes@usp.br [Department of Genetics, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil)

    2016-07-15

    The discovery that the regenerative properties of bone marrow multipotent mesenchymal stromal cells (BM-MSCs) could collaterally favor neoplastic progression has led to a great interest in the function of these cells in tumors. However, the effect of BM-MSCs on colonization, a rate-limiting step of the metastatic cascade, is unknown. In this study, we investigated the effect of BM-MSCs on metastatic outgrowth of B16-F10 melanoma cells. In in vitro experiments, direct co-culture assays demonstrated that BM-MSCs stimulated the proliferation of B16-F10 cells in a dose-dependent manner. For in vivo experiments, luciferase-expressing B16-F10 cells were injected through tail vein and mice were subsequently treated with four systemic injections of BM-MSCs. In vivo bioluminescent imaging during 16 days demonstrated that BM-MSCs enhanced the colonization of lungs by B16-F10 cells, which correlated with a 2-fold increase in the number of metastatic foci. Flow cytometry analysis of lungs demonstrated that although mice harboring B16-F10 metastases displayed more endothelial cells, CD4 T and CD8 T lymphocytes in the lungs in comparison to metastases-free mice, BM-MSCs did not alter the number of these cells. Interestingly, BM-MSCs inoculation resulted in a 2-fold increase in the number of CD11b{sup +} myeloid cells in the lungs of melanoma-bearing animals, a cell population previously described to organize “premetastatic niches” in experimental models. These findings indicate that BM-MSCs provide support to B16-F10 cells to overcome the constraints that limit metastatic outgrowth and that these effects might involve the interplay between BM-MSCs, CD11b{sup +} myeloid cells and tumor cells. - Highlights: • BM-MSCs enhanced B16-F10 proliferation in a dose-dependent manner in vitro. • BM-MSCs facilitated lung colonization by B16-F10 melanoma cells. • BM-MSCs administration did not alter the number of endothelial cells and T lymphocytes in the lungs. • BM-MSCs enhanced

  14. [Psychological aspects of emotional regulation in smoking dependency].

    Science.gov (United States)

    Carton, S

    2001-04-01

    We reviewed the literature on the relationships between smoking and affect regulation. There is strong evidence that vulnerability to smoking dependence is a function of a high initial sensitivity to nicotine, which produces reinforcing consequences that lead to chronic use. These strong reinforcers of tobacco dependence include regulation of mood and modulation of arousal. We focused on studies concerned with the subjective component of arousal and emotional experience. We discuss first the models and classifications used to differentiate types of smoking as related to the management of emotions and studies evaluating the stimulant and subjective effects of smoking behavior, questioning the paradoxical tranquilizing and anxiety-reducing effects of nicotine. We also looked into the mood regulation effects that may explain the strong relationships observed between depression and smoking and finally focus on some of the personality risk factors that may make individuals more susceptible to these rewarding properties of smoking.

  15. Therapeutic Effects of Myeloid Cell Leukemia-1 siRNA on Human Acute Myeloid Leukemia Cells

    Directory of Open Access Journals (Sweden)

    Hadi Karami

    2014-05-01

    Full Text Available Purpose: Up-regulation of Mcl-1, a known anti-apoptotic protein, is associated with the survival and progression of various malignancies including leukemia. The aim of this study was to explore the effect of Mcl-1 small interference RNA (siRNA on the proliferation and apoptosis of HL-60 acute myeloid leukemia (AML cells. Methods: siRNA transfection was performed using Lipofectamine™2000 reagent. Relative mRNA and protein expressions were quantified by quantitative real-time PCR and Western blotting, respectively. Trypan blue assay was performed to assess tumor cell proliferation after siRNA transfection. The cytotoxic effect of Mcl-1 siRNA on leukemic cells was measured using MTT assay. Apoptosis was detected using ELISA cell death assay. Results: Mcl-1 siRNA clearly lowered both Mcl-1 mRNA and protein levels in a time-dependent manner, leading to marked inhibition of cell survival and proliferation. Furthermore, Mcl-1 down-regulation significantly enhanced the extent of HL-60 apoptotic cells. Conclusion: Our results suggest that the down-regulation of Mcl-1 by siRNA can effectively trigger apoptosis and inhibit the proliferation of leukemic cells. Therefore, Mcl-1 siRNA may be a potent adjuvant in AML therapy.

  16. Metabolic-flux dependent regulation of microbial physiology.

    Science.gov (United States)

    Litsios, Athanasios; Ortega, Álvaro D; Wit, Ernst C; Heinemann, Matthias

    2018-04-01

    According to the most prevalent notion, changes in cellular physiology primarily occur in response to altered environmental conditions. Yet, recent studies have shown that changes in metabolic fluxes can also trigger phenotypic changes even when environmental conditions are unchanged. This suggests that cells have mechanisms in place to assess the magnitude of metabolic fluxes, that is, the rate of metabolic reactions, and use this information to regulate their physiology. In this review, we describe recent evidence for metabolic flux-sensing and flux-dependent regulation. Furthermore, we discuss how such sensing and regulation can be mechanistically achieved and present a set of new candidates for flux-signaling metabolites. Similar to metabolic-flux sensing, we argue that cells can also sense protein translation flux. Finally, we elaborate on the advantages that flux-based regulation can confer to cells. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. NK-, NKT- and CD8-Derived IFNγ Drives Myeloid Cell Activation and Erythrophagocytosis, Resulting in Trypanosomosis-Associated Acute Anemia.

    Directory of Open Access Journals (Sweden)

    Jennifer Cnops

    2015-06-01

    Full Text Available African trypanosomes are the causative agents of Human African Trypanosomosis (HAT/Sleeping Sickness and Animal African Trypanosomosis (AAT/Nagana. A common hallmark of African trypanosome infections is inflammation. In murine trypanosomosis, the onset of inflammation occurs rapidly after infection and is manifested by an influx of myeloid cells in both liver and spleen, accompanied by a burst of serum pro-inflammatory cytokines. Within 48 hours after reaching peak parasitemia, acute anemia develops and the percentage of red blood cells drops by 50%. Using a newly developed in vivo erythrophagocytosis assay, we recently demonstrated that activated cells of the myeloid phagocytic system display enhanced erythrophagocytosis causing acute anemia. Here, we aimed to elucidate the mechanism and immune pathway behind this phenomenon in a murine model for trypanosomosis. Results indicate that IFNγ plays a crucial role in the recruitment and activation of erythrophagocytic myeloid cells, as mice lacking the IFNγ receptor were partially protected against trypanosomosis-associated inflammation and acute anemia. NK and NKT cells were the earliest source of IFNγ during T. b. brucei infection. Later in infection, CD8+ and to a lesser extent CD4+ T cells become the main IFNγ producers. Cell depletion and transfer experiments indicated that during infection the absence of NK, NKT and CD8+ T cells, but not CD4+ T cells, resulted in a reduced anemic phenotype similar to trypanosome infected IFNγR-/- mice. Collectively, this study shows that NK, NKT and CD8+ T cell-derived IFNγ is a critical mediator in trypanosomosis-associated pathology, driving enhanced erythrophagocytosis by myeloid phagocytic cells and the induction of acute inflammation-associated anemia.

  18. Association of Increased F4/80high Macrophages With Suppression of Serum-Transfer Arthritis in Mice With Reduced FLIP in Myeloid Cells.

    Science.gov (United States)

    Huang, Qi-Quan; Birkett, Robert; Doyle, Renee E; Haines, G Kenneth; Perlman, Harris; Shi, Bo; Homan, Philip; Xing, Lianping; Pope, Richard M

    2017-09-01

    Macrophages are critical in the pathogenesis of rheumatoid arthritis (RA). We recently demonstrated that FLIP is necessary for the differentiation and/or survival of macrophages. We also showed that FLIP is highly expressed in RA synovial macrophages. This study was undertaken to determine if a reduction in FLIP in mouse macrophages reduces synovial tissue macrophages and ameliorates serum-transfer arthritis. Mice with Flip deleted in myeloid cells (Flip f/f LysM c/+ mice) and littermate controls were used. Arthritis was induced by intraperitoneal injection of K/BxN serum. Disease severity was evaluated by clinical score and change in ankle thickness, and joints were examined by histology and immunohistochemistry. Cells were isolated from the ankles and bone marrow of the mice and examined by flow cytometry, real-time quantitative reverse transcriptase-polymerase chain reaction, or Western blotting. In contrast to expectations, Flip f/f LysM c/+ mice developed more severe arthritis early in the clinical course, but peak arthritis was attenuated and the resolution phase more complete than in control mice. Prior to the induction of serum-transfer arthritis, the number of tissue-resident macrophages was reduced. On day 9 after arthritis induction, the number of F4/80 high macrophages in the joints of the Flip f/f LysM c/+ mice was not decreased, but increased. FLIP was reduced in the F4/80 high macrophages in the ankles of the Flip f/f LysM c/+ mice, while F4/80 high macrophages expressed an antiinflammatory phenotype in both the Flip f/f LysM c/+ and control mice. Our observations suggest that reducing FLIP in macrophages by increasing the number of antiinflammatory macrophages may be an effective therapeutic approach to suppress inflammation, depending on the disease stage. © 2017, American College of Rheumatology.

  19. CodY-Dependent Regulation of Sporulation in Clostridium difficile.

    Science.gov (United States)

    Nawrocki, Kathryn L; Edwards, Adrianne N; Daou, Nadine; Bouillaut, Laurent; McBride, Shonna M

    2016-08-01

    Clostridium difficile must form a spore to survive outside the gastrointestinal tract. The factors that trigger sporulation in C. difficile remain poorly understood. Previous studies have suggested that a link exists between nutritional status and sporulation initiation in C. difficile In this study, we investigated the impact of the global nutritional regulator CodY on sporulation in C. difficile strains from the historical 012 ribotype and the current epidemic 027 ribotype. Sporulation frequencies were increased in both backgrounds, demonstrating that CodY represses sporulation in C. difficile The 027 codY mutant exhibited a greater increase in spore formation than the 012 codY mutant. To determine the role of CodY in the observed sporulation phenotypes, we examined several factors that are known to influence sporulation in C. difficile Using transcriptional reporter fusions and quantitative reverse transcription-PCR (qRT-PCR) analysis, we found that two loci associated with the initiation of sporulation, opp and sinR, are regulated by CodY. The data demonstrate that CodY is a repressor of sporulation in C. difficile and that the impact of CodY on sporulation and expression of specific genes is significantly influenced by the strain background. These results suggest that the variability of CodY-dependent regulation is an important contributor to virulence and sporulation in current epidemic isolates. This report provides further evidence that nutritional state, virulence, and sporulation are linked in C. difficile This study sought to examine the relationship between nutrition and sporulation in C. difficile by examining the global nutritional regulator CodY. CodY is a known virulence and nutritional regulator of C. difficile, but its role in sporulation was unknown. Here, we demonstrate that CodY is a negative regulator of sporulation in two different ribotypes of C. difficile We also demonstrate that CodY regulates known effectors of sporulation, Opp and Sin

  20. BMP signaling regulates satellite cell-dependent postnatal muscle growth.

    Science.gov (United States)

    Stantzou, Amalia; Schirwis, Elija; Swist, Sandra; Alonso-Martin, Sonia; Polydorou, Ioanna; Zarrouki, Faouzi; Mouisel, Etienne; Beley, Cyriaque; Julien, Anaïs; Le Grand, Fabien; Garcia, Luis; Colnot, Céline; Birchmeier, Carmen; Braun, Thomas; Schuelke, Markus; Relaix, Frédéric; Amthor, Helge

    2017-08-01

    Postnatal growth of skeletal muscle largely depends on the expansion and differentiation of resident stem cells, the so-called satellite cells. Here, we demonstrate that postnatal satellite cells express components of the bone morphogenetic protein (BMP) signaling machinery. Overexpression of noggin in postnatal mice (to antagonize BMP ligands), satellite cell-specific knockout of Alk3 (the gene encoding the BMP transmembrane receptor) or overexpression of inhibitory SMAD6 decreased satellite cell proliferation and accretion during myofiber growth, and ultimately retarded muscle growth. Moreover, reduced BMP signaling diminished the adult satellite cell pool. Abrogation of BMP signaling in satellite cell-derived primary myoblasts strongly diminished cell proliferation and upregulated the expression of cell cycle inhibitors p21 and p57 In conclusion, these results show that BMP signaling defines postnatal muscle development by regulating satellite cell-dependent myofiber growth and the generation of the adult muscle stem cell pool. © 2017. Published by The Company of Biologists Ltd.

  1. FOXO-dependent regulation of innate immune homeostasis.

    Science.gov (United States)

    Becker, Thomas; Loch, Gerrit; Beyer, Marc; Zinke, Ingo; Aschenbrenner, Anna C; Carrera, Pilar; Inhester, Therese; Schultze, Joachim L; Hoch, Michael

    2010-01-21

    The innate immune system represents an ancient host defence mechanism that protects against invading microorganisms. An important class of immune effector molecules to fight pathogen infections are antimicrobial peptides (AMPs) that are produced in plants and animals. In Drosophila, the induction of AMPs in response to infection is regulated through the activation of the evolutionarily conserved Toll and immune deficiency (IMD) pathways. Here we show that AMP activation can be achieved independently of these immunoregulatory pathways by the transcription factor FOXO, a key regulator of stress resistance, metabolism and ageing. In non-infected animals, AMP genes are activated in response to nuclear FOXO activity when induced by starvation, using insulin signalling mutants, or by applying small molecule inhibitors. AMP induction is lost in foxo null mutants but enhanced when FOXO is overexpressed. Expression of AMP genes in response to FOXO activity can also be triggered in animals unable to respond to immune challenges due to defects in both the Toll and IMD pathways. Molecular experiments at the Drosomycin promoter indicate that FOXO directly binds to its regulatory region, thereby inducing its transcription. In vivo studies in Drosophila, but also studies in human lung, gut, kidney and skin cells indicate that a FOXO-dependent regulation of AMPs is evolutionarily conserved. Our results indicate a new mechanism of cross-regulation of metabolism and innate immunity by which AMP genes can be activated under normal physiological conditions in response to the oscillating energy status of cells and tissues. This regulation seems to be independent of the pathogen-responsive innate immunity pathways whose activation is often associated with tissue damage and repair. The sparse production of AMPs in epithelial tissues in response to FOXO may help modulating the defence reaction without harming the host tissues, in particular when animals are suffering from energy shortage

  2. Pathologic and Protective Roles for Microglial Subsets and Bone Marrow- and Blood-Derived Myeloid Cells in Central Nervous System Inflammation

    DEFF Research Database (Denmark)

    Wlodarczyk, Agnieszka; Cédile, Oriane; Jensen, Kirstine Nolling

    2015-01-01

    Inflammation is a series of processes designed for eventual clearance of pathogens and repair of damaged tissue. In the context of autoimmune recognition, inflammatory processes are usually considered to be pathological. This is also true for inflammatory responses in the central nervous system...... (CNS). However, as in other tissues, neuroinflammation can have beneficial as well as pathological outcomes. The complex role of encephalitogenic T cells in multiple sclerosis and its animal model experimental autoimmune encephalomyelitis (EAE) may derive from heterogeneity of the myeloid cells...... with which these T cells interact within the CNS. Myeloid cells, including resident microglia and infiltrating bone marrow-derived cells, such as dendritic cells (DC) and monocytes/macrophages [bone marrow-derived macrophages (BMDM)], are highly heterogeneous populations that may be involved in neurotoxicity...

  3. Myeloid cells expressing VEGF and arginase-1 following uptake of damaged retinal pigment epithelium suggests potential mechanism that drives the onset of choroidal angiogenesis in mice.

    Directory of Open Access Journals (Sweden)

    Jian Liu

    Full Text Available Whilst data recognise both myeloid cell accumulation during choroidal neovascularisation (CNV as well as complement activation, none of the data has presented a clear explanation for the angiogenic drive that promotes pathological angiogenesis. One possibility that is a pre-eminent drive is a specific and early conditioning and activation of the myeloid cell infiltrate. Using a laser-induced CNV murine model, we have identified that disruption of retinal pigment epithelium (RPE and Bruch's membrane resulted in an early recruitment of macrophages derived from monocytes and microglia, prior to angiogenesis and contemporaneous with lesional complement activation. Early recruited CD11b(+ cells expressed a definitive gene signature of selective inflammatory mediators particularly a pronounced Arg-1 expression. Accumulating macrophages from retina and peripheral blood were activated at the site of injury, displaying enhanced VEGF expression, and notably prior to exaggerated VEGF expression from RPE, or earliest stages of angiogenesis. All of these initial events, including distinct VEGF (+ Arg-1(+ myeloid cells, subsided when CNV was established and at the time RPE-VEGF expression was maximal. Depletion of inflammatory CCR2-positive monocytes confirmed origin of infiltrating monocyte Arg-1 expression, as following depletion Arg-1 signal was lost and CNV suppressed. Furthermore, our in vitro data supported a myeloid cell uptake of damaged RPE or its derivatives as a mechanism generating VEGF (+ Arg-1(+ phenotype in vivo. Our results reveal a potential early driver initiating angiogenesis via myeloid-derived VEGF drive following uptake of damaged RPE and deliver an explanation of why CNV develops during any of the stages of macular degeneration and can be explored further for therapeutic gain.

  4. Cyclin-dependent kinases regulate apoptosis of intestinal epithelial cells

    Science.gov (United States)

    Bhattacharya, Sujoy; Ray, Ramesh M.; Johnson, Leonard R.

    2014-01-01

    Homeostasis of the gastrointestinal epithelium is dependent upon a balance between cell proliferation and apoptosis. Cyclin-dependent kinases (Cdks) are well known for their role in cell proliferation. Previous studies from our group have shown that polyamine-depletion of intestinal epithelial cells (IEC-6) decreases cyclin-dependent kinase 2 (Cdk2) activity, increases p53 and p21Cip1 protein levels, induces G1 arrest, and protects cells from camptothecin (CPT)-induced apoptosis. Although emerging evidence suggests that members of the Cdk family are involved in the regulation of apoptosis, their roles directing apoptosis of IEC-6 cells are not known. In this study, we report that inhibition of Cdk1, 2, and 9 (with the broad range Cdk inhibitor, AZD5438) in proliferating IEC-6 cells triggered DNA damage, activated p53 signaling, inhibited proliferation, and induced apoptosis. By contrast, inhibition of Cdk2 (with NU6140) increased p53 protein and activity, inhibited proliferation, but had no effect on apoptosis. Notably, AZD5438 sensitized, whereas, NU6140 rescued proliferating IEC-6 cells from CPT-induced apoptosis. However, in colon carcinoma (Caco2) cells with mutant p53, treatment with either AZD5438 or NU6140 blocked proliferation, albeit more robustly with AZD5438. Both Cdk inhibitors induced apoptosis in Caco2 cells in a p53-independent manner. In serum starved quiescent IEC-6 cells, both AZD5438 and NU6140 decreased TNF- /CPT-induced activation of p53 and, consequently, rescued cells from apoptosis, indicating that sustained Cdk activity is required for apoptosis of quiescent cells. Furthermore, AZD5438 partially reversed the protective effect of polyamine depletion whereas NU6140 had no effect. Together, these results demonstrate that Cdks possess opposing roles in the control of apoptosis in quiescent and proliferating cells. In addition, Cdk inhibitors uncouple proliferation from apoptosis in a p53-dependent manner. PMID:24242917

  5. MCPIP-1, Alias Regnase-1, Controls Epithelial Inflammation by Posttranscriptional Regulation of IL-8 Production.

    Science.gov (United States)

    Dobosz, Ewelina; Wilamowski, Mateusz; Lech, Maciej; Bugara, Beata; Jura, Jolanta; Potempa, Jan; Koziel, Joanna

    2016-01-01

    Pattern recognition receptors are critical for the detection of invading microorganisms. They activate multiple pathways that lead to the induction of proinflammatory responses and pathogen clearance. The intensity and duration of this immune reaction must be tightly controlled spatially and temporally in every tissue by different negative regulators. We hypothesized that monocyte chemoattractant protein-1-induced protein-1 (MCPIP-1) might play a role in maintaining immune homeostasis in the epithelium both under physiological conditions and upon bacterial infection. To this end, we examined the distribution of the MCPIP-1 transcript and protein in various tissues. The MCPIP-1 protein level was higher in epithelial cells than in myeloid cells. MCPIP-1 exerted RNase activity towards the interleukin (IL)-8 transcript and the lifespan of IL-8 was determined by the presence of the stem-loops/hairpin structures at the 3'UTR region of IL-8 mRNA. Moreover, using fully active, purified recombinant MCPIP-1 protein, we elucidated the mechanism by which MCPIP-1 controls the IL-8 mRNA level. In conclusion, we uncovered a novel IL-8-dependent mechanism via which MCPIP-1 maintains epithelial homeostasis. This study reveals for the first time that MCPIP-1 plays a crucial anti-inflammatory role not only in myeloid cells but also in epithelial cells. © 2016 S. Karger AG, Basel.

  6. Thioredoxin h regulates calcium dependent protein kinases in plasma membranes.

    Science.gov (United States)

    Ueoka-Nakanishi, Hanayo; Sazuka, Takashi; Nakanishi, Yoichi; Maeshima, Masayoshi; Mori, Hitoshi; Hisabori, Toru

    2013-07-01

    Thioredoxin (Trx) is a key player in redox homeostasis in various cells, modulating the functions of target proteins by catalyzing a thiol-disulfide exchange reaction. Target proteins of cytosolic Trx-h of higher plants were studied, particularly in the plasma membrane, because plant plasma membranes include various functionally important protein molecules such as transporters and signal receptors. Plasma membrane proteins from Arabidopsis thaliana cell cultures were screened using a resin Trx-h1 mutant-immobilized, and a total of 48 candidate proteins obtained. These included two calcium-sensing proteins: a phosphoinositide-specific phospholipase 2 (AtPLC2) and a calcium-dependent protein kinase 21 (AtCPK21). A redox-dependent change in AtCPK21 kinase activity was demonstrated in vitro. Oxidation of AtCPK21 resulted in a decrease in kinase activity to 19% of that of untreated AtCPK21, but Trx-h1 effectively restored the activity to 90%. An intramolecular disulfide bond (Cys97-Cys108) that is responsible for this redox modulation was then identified. In addition, endogenous AtCPK21 was shown to be oxidized in vivo when the culture cells were treated with H2 O2 . These results suggest that redox regulation of AtCPK21 by Trx-h in response to external stimuli is important for appropriate cellular responses. The relationship between the redox regulation system and Ca(2+) signaling pathways is discussed. © 2013 The Authors. FEBS Journal published by John Wiley & Sons Ltd on behalf of FEBS.

  7. Cyclin-dependent kinase 5 regulates degranulation in human eosinophils.

    Science.gov (United States)

    Odemuyiwa, Solomon O; Ilarraza, Ramses; Davoine, Francis; Logan, Michael R; Shayeganpour, Anooshirvan; Wu, Yingqi; Majaesic, Carina; Adamko, Darryl J; Moqbel, Redwan; Lacy, Paige

    2015-04-01

    Degranulation from eosinophils in response to secretagogue stimulation is a regulated process that involves exocytosis of granule proteins through specific signalling pathways. One potential pathway is dependent on cyclin-dependent kinase 5 (Cdk5) and its effector molecules, p35 and p39, which play a central role in neuronal cell exocytosis by phosphorylating Munc18, a regulator of SNARE binding. Emerging evidence suggests a role for Cdk5 in exocytosis in immune cells, although its role in eosinophils is not known. We sought to examine the expression of Cdk5 and its activators in human eosinophils, and to assess the role of Cdk5 in eosinophil degranulation. We used freshly isolated human eosinophils and analysed the expression of Cdk5, p35, p39 and Munc18c by Western blot, RT-PCR, flow cytometry and immunoprecipitation. Cdk5 kinase activity was determined following eosinophil activation. Cdk5 inhibitors were used (roscovitine, AT7519 and small interfering RNA) to determine its role in eosinophil peroxidase (EPX) secretion. Cdk5 was expressed in association with Munc18c, p35 and p39, and phosphorylated following human eosinophil activation with eotaxin/CCL11, platelet-activating factor, and secretory IgA-Sepharose. Cdk5 inhibitors (roscovitine, AT7519) reduced EPX release when cells were stimulated by PMA or secretory IgA. In assays using small interfering RNA knock-down of Cdk5 expression in human eosinophils, we observed inhibition of EPX release. Our findings suggest that in activated eosinophils, Cdk5 is phosphorylated and binds to Munc18c, resulting in Munc18c release from syntaxin-4, allowing SNARE binding and vesicle fusion, with subsequent eosinophil degranulation. Our work identifies a novel role for Cdk5 in eosinophil mediator release by agonist-induced degranulation. © 2014 John Wiley & Sons Ltd.

  8. Anomalies in the Fujikawa method using parameter-dependent regulators

    International Nuclear Information System (INIS)

    Urrutia, L.F.; Vergara, J.D.

    1992-01-01

    We propose an extended definition of the regularized Jacobian which allows the calculation of anomalies using parameter-dependent regulators in the Fujikawa approach. This extension incorporates the basic Green's function of the problem in the regularized Jacobian, allowing us to interpret a specific regularization procedure as a way of selecting the finite part of the Green's function, in complete analogy with what is done at the level of the effective action. In this way we are able to consider the effect of counterterms in the regularized Jacobian in order to relate different regularization procedures. We also discuss the ambiguities that arise in our prescription due to some freedom in the place where we can insert the regulator, using charge-conjugation invariance as a guiding principle. The method is applied to the case of vector and axial-vector anomalies in two- and four-dimensional quantum electrodynamics. In the first situation we recover the standard family of anomalies calculated by the point-splitting regularization prescription. We also study in detail an alternative choice in the position of the regulator and we calculate explicitly all the currents that generate the families of anomalies that we are considering. Next we extend the calculation to four dimensions, using the same prescriptions as before, and we compare the results with those obtained from the point-splitting calculation, which we also perform in the case of the vector anomaly. A discussion of the relation among the results obtained by different regularization prescriptions is given in terms of the allowed counterterms in the regularized Jacobian, which are highly constrained by the requirement of charge-conjugation invariance

  9. Androgen-Dependent Regulation of Human MUC1 Mucin Expression

    Directory of Open Access Journals (Sweden)

    Stephen Mitchell

    2002-01-01

    Full Text Available MUC1 mucin is transcriptionally regulated by estrogen, progesterone, and glucocorticoids. Our objective was to determine whether androgen receptor. (20AR activation regulates expression of MUC1. The following breast and prostatic cell lines were phenotyped and grouped according to AR and MUC1protein expression: 1 AR+MUCi + [DAR17+19. (20AR transfectants of DU-145, ZR-75-1, MDA-MB-453, and T47D]; 2 AR-MUCi+ [DZeoi. (20AR- vector control, DU-145, BT20, MDA-MB231, and MCF7]; 3 AIR +MUCi -. (20LNCaP and LNCaP-r. Cell proliferation was determined using the MTT assay in the presence of synthetic androgen R1881, 0.1 pM to 1 µM. Cell surface MUC1expression was determined by flow cytometry in the presence or absence of oestradiol, medroxy progesterone acetate or R1881, with and without 4 hydroxy-flutamide. (204-OH, a nonsteroidal AR antagonist. The functional significance of MUC1expression was investigated with a cell-cell aggregation assay. Only AR+ MUC1 + cell lines showed a significant increase in MUC1expression with AR activation. (20P. (20range =.01 to .0001, reversed in the presence of 4-OHF. Cell proliferation was unaffected. Increased expression of MUC1was associated with a significant. (20P. (20range =.002 to .001 reduction in cell-cell adhesion. To our knowledge, this is the first description of androgen-dependent regulation of MUC1mucin. This is also functionally associated with decreased cell-cell adhesion, a recognised feature of progressive malignancy. These findings have important implications for physiological and pathological processes.

  10. Interleukin-33-Activated Islet-Resident Innate Lymphoid Cells Promote Insulin Secretion through Myeloid Cell Retinoic Acid Production.

    Science.gov (United States)

    Dalmas, Elise; Lehmann, Frank M; Dror, Erez; Wueest, Stephan; Thienel, Constanze; Borsigova, Marcela; Stawiski, Marc; Traunecker, Emmanuel; Lucchini, Fabrizio C; Dapito, Dianne H; Kallert, Sandra M; Guigas, Bruno; Pattou, Francois; Kerr-Conte, Julie; Maechler, Pierre; Girard, Jean-Philippe; Konrad, Daniel; Wolfrum, Christian; Böni-Schnetzler, Marianne; Finke, Daniela; Donath, Marc Y

    2017-11-21

    Pancreatic-islet inflammation contributes to the failure of β cell insulin secretion during obesity and type 2 diabetes. However, little is known about the nature and function of resident immune cells in this context or in homeostasis. Here we show that interleukin (IL)-33 was produced by islet mesenchymal cells and enhanced by a diabetes milieu (glucose, IL-1β, and palmitate). IL-33 promoted β cell function through islet-resident group 2 innate lymphoid cells (ILC2s) that elicited retinoic acid (RA)-producing capacities in macrophages and dendritic cells via the secretion of IL-13 and colony-stimulating factor 2. In turn, local RA signaled to the β cells to increase insulin secretion. This IL-33-ILC2 axis was activated after acute β cell stress but was defective during chronic obesity. Accordingly, IL-33 injections rescued islet function in obese mice. Our findings provide evidence that an immunometabolic crosstalk between islet-derived IL-33, ILC2s, and myeloid cells fosters insulin secretion. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Role of the mitochondrial amino acid pool in the differential sensitivity of erythroid and myeloid cells to chloramphenicol

    International Nuclear Information System (INIS)

    Abou-Khalil, S.; Abou-Khalil, W.H.; Whitney, P.L.; Yunis, A.A.

    1986-01-01

    Previous studies in the authors laboratory have suggested that mitochondrial amino acid (AA) pool is involved in the differential sensitivity of erythroid and myeloid cells to chloramphenicol (CAP). The present study examines the role of AA pool by analysis of its composition and testing the effects of its major components. The endogenous AA composition of isolated mitochondria protein was determined using a JEOL 5AH AA analyzer. L-( 14 C) leucine incorporation into mitochondrial protein was used to measure the rate of protein synthesis. Analysis of the endogenous pool in erythroleukemia (EM) and chloroleukemia (CM) mitochrondria showed similar total amount of AAs. However, some AAs were present in significantly higher or lower quantity within EM and CM (i.e. EM had about 2-fold higher glycine content). When compensating for each low AA addition of that particular acid to the reaction medium, only glycine and serine had significant effect. Thus, the addition of increasing concentrations of glycine or serine enhanced the sensitivity to CAP from 14% to 49-51% in CM but not in EM. Other AAs gave little or no effect. Since glycine is one of the first reactants in heme biosynthesis within mitochondria and is interconvertible with serine, it would appear that erythroid cells sensitivity to CAP is determined by the mitochondrial glycine-serine pool and may be somehow related of the pathway to heme biosynthesis in these cells

  12. Activation of Liver X Receptor Decreases Atherosclerosis in Ldlr−/− mice in the Absence of ABCA1 and ABCG1 in Myeloid Cells

    Science.gov (United States)

    Kappus, Mojdeh S.; Murphy, Andrew J.; Abramowicz, Sandra; Ntonga, Vusisizwe; Welch, Carrie L.; Tall, Alan R.; Westerterp, Marit

    2014-01-01

    Objective Liver X Receptor (LXR) activators decrease atherosclerosis in mice. LXR activators (1) directly up-regulate genes involved in reverse cholesterol transport (RCT) and (2) exert anti-inflammatory effects mediated by transrepression of NFκB target genes. We investigated whether myeloid cell deficiency of ATP-binding cassette transporters A1 and G1 (ABCA1/G1), principal targets of LXR that promote macrophage cholesterol efflux and initiate RCT, would abolish the beneficial effects of LXR activation on atherosclerosis. Approach and Results LXR activator T0901317 (T0) substantially reduced inflammatory gene expression in macrophages lacking ABCA1/G1. Ldlr−/− mice were transplanted with Abca1−/−Abcg1−/− or wild-type bone marrow (BM) and fed a Western-type diet (WTD) for 6 weeks with or without T0 supplementation. Abca1/g1 BM deficiency increased atherosclerotic lesion complexity and inflammatory cell infiltration into the adventitia and myocardium. T0 markedly decreased lesion area, complexity and inflammatory cell infiltration in the Abca1−/−Abcg1−/− BM transplanted mice. To investigate whether this was due to macrophage Abca1/g1 deficiency, Ldlr−/− mice were transplanted with LysmCreAbca1fl/flAbcg1fl/fl or Abca1fl/flAbcg1fl/fl BM and fed WTD with or without the more specific LXR agonist GW3965 for 12 weeks. GW3965 decreased lesion size in both groups and the decrease was more prominent in the LysmCreAbca1fl/flAbcg1fl/fl group. Conclusions The results suggest that anti-inflammatory effects of LXR activators are of key importance to their anti-atherosclerotic effects in vivo independent of cholesterol efflux pathways mediated by macrophage ABCA1/G1. This has implications for the development of LXR activators that lack adverse effects on lipogenic genes while maintaining the ability to trans-repress inflammatory genes. PMID:24311381

  13. Myeloid cell leukemia-1 (Mc1-1 is a candidate target gene of hypoxia-inducible factor-1 (HIF-1 in the testis

    Directory of Open Access Journals (Sweden)

    Palladino Michael A

    2012-12-01

    Full Text Available Abstract Background Spermatic cord torsion can lead to testis ischemia (I and subsequent ischemia-reperfusion (I/R causing germ cell-specific apoptosis. Previously, we demonstrated that the hypoxia-inducible factor-1 (HIF-1 transcription factor, a key regulator of physiological responses to hypoxia, is abundant in Leydig cells in normoxic and ischemic testes. We hypothesize that testicular HIF-1 activates the expression of antiapoptotic target genes to protect Leydig cells from apoptosis. In silico analysis of testis genes containing a consensus hypoxia response element (HRE, 5’-RCGTG-3’ identified myeloid cell leukemia-1 (Mcl-1 as a potential HIF-1 target gene. The purpose of this study was to determine whether HIF-1 shows DNA-binding activity in normoxic and ischemic testes and whether Mcl-1 is a target gene of testicular HIF-1. Methods The testicular HIF-1 DNA-binding capacity was analyzed in vitro using a quantitative enzyme-linked immunosorbent assay (ELISA and electrophoretic mobility shift assays (EMSA. MCL-1 protein expression was evaluated by immunoblot analysis and immunohistochemistry. The binding of testicular HIF-1 to the Mcl-1 gene was examined via chromatin immunoprecipitation (ChIP analysis. Results The ELISA and EMSA assays demonstrated that testicular HIF-1 from normoxic and ischemic testes binds DNA equally strongly, suggesting physiological roles for HIF-1 in the normoxic testis, unlike most tissues in which HIF-1 is degraded under normoxic conditions and is only activated by hypoxia. MCL-1 protein was determined to be abundant in both normoxic and ischemic testes and expressed in Leydig cells. In a pattern identical to that of HIF-1 expression, the steady-state levels of MCL-1 were not significantly affected by I or I/R and MCL-1 co-localized with HIF-1α in Leydig cells. Chromatin immunoprecipitation (ChIP analysis using a HIF-1 antibody revealed sequences enriched for the Mcl-1 promoter. Conclusions The results

  14. Concentration and length dependence of DNA looping in transcriptional regulation.

    Directory of Open Access Journals (Sweden)

    Lin Han

    2009-05-01

    Full Text Available In many cases, transcriptional regulation involves the binding of transcription factors at sites on the DNA that are not immediately adjacent to the promoter of interest. This action at a distance is often mediated by the formation of DNA loops: Binding at two or more sites on the DNA results in the formation of a loop, which can bring the transcription factor into the immediate neighborhood of the relevant promoter. These processes are important in settings ranging from the historic bacterial examples (bacterial metabolism and the lytic-lysogeny decision in bacteriophage, to the modern concept of gene regulation to regulatory processes central to pattern formation during development of multicellular organisms. Though there have been a variety of insights into the combinatorial aspects of transcriptional control, the mechanism of DNA looping as an agent of combinatorial control in both prokaryotes and eukaryotes remains unclear. We use single-molecule techniques to dissect DNA looping in the lac operon. In particular, we measure the propensity for DNA looping by the Lac repressor as a function of the concentration of repressor protein and as a function of the distance between repressor binding sites. As with earlier single-molecule studies, we find (at least two distinct looped states and demonstrate that the presence of these two states depends both upon the concentration of repressor protein and the distance between the two repressor binding sites. We find that loops form even at interoperator spacings considerably shorter than the DNA persistence length, without the intervention of any other proteins to prebend the DNA. The concentration measurements also permit us to use a simple statistical mechanical model of DNA loop formation to determine the free energy of DNA looping, or equivalently, the for looping.

  15. 38 CFR 3.270 - Applicability of various dependency, income and estate regulations.

    Science.gov (United States)

    2010-07-01

    ... dependency, income and estate regulations. 3.270 Section 3.270 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Dependency, Income and Estate § 3.270 Applicability of various dependency, income and estate regulations. (a...

  16. Physiological roles of Regulated Ire1 Dependent Decay

    Directory of Open Access Journals (Sweden)

    Dina S. Coelho

    2014-04-01

    Full Text Available Ire1 is an important transducer of the Unfolded Protein Response (UPR that is activated by the accumulation of misfolded proteins in the Endoplamic Reticulum (ER stress. Activated Ire1 mediates the splicing of an intron from the mRNA of Xbp1, causing a frame-shift during translation and introducing a new carboxyl domain in the Xbp1 protein, which only then becomes a fully functional transcription factor. Studies using cell culture systems demonstrated that Ire1 also promotes the degradation of mRNAs encoding mostly ER-targeted proteins, to reduce the load of incoming ER client proteins during ER stress. This process was called RIDD (regulated Ire1-dependent decay, but its physiological significance remained poorly characterized beyond cell culture systems. Here we review several recent studies that have highlighted the physiological roles of RIDD in specific biological paradigms, such as photoreceptor differentiation in Drosophila or mammalian liver and endocrine pancreas function. These studies demonstrate the importance of RIDD in tissues undergoing intense secretory function and highlight the physiologic role of RIDD during UPR activation in cells and organisms.

  17. Regulation of replicative senescence by NADP+ -dependent isocitrate dehydrogenase.

    Science.gov (United States)

    Kil, In Sup; Huh, Tae Lin; Lee, Young Sup; Lee, You Mie; Park, Jeen-Woo

    2006-01-01

    The free radical hypothesis of aging postulates that senescence is due to an accumulation of cellular oxidative damage, caused largely by reactive oxygen species that are produced as by-products of normal metabolic processes. Recently, we demonstrated that the control of cytosolic and mitochondrial redox balance and the cellular defense against oxidative damage is one of the primary functions of cytosolic (IDPc) and mitochondrial NADP+ -dependent isocitrate dehydrogenase (IDPm) by supplying NADPH for antioxidant systems. In this paper, we demonstrate that modulation of IDPc or IDPm activity in IMR-90 cells regulates cellular redox status and replicative senescence. When we examined the regulatory role of IDPc and IDPm against the aging process with IMR-90 cells transfected with cDNA for IDPc or IDPm in sense and antisense orientations, a clear inverse relationship was observed between the amount of IDPc or IDPm expressed in target cells and their susceptibility to senescence, which was reflected by changes in replicative potential, cell cycle, senescence-associated beta-galactosidase activity, expression of p21 and p53, and morphology of cells. Furthermore, lipid peroxidation, oxidative DNA damage, and intracellular peroxide generation were higher and cellular redox status shifted to a prooxidant condition in the cell lines expressing the lower level of IDPc or IDPm. The results suggest that IDPc and IDPm play an important regulatory role in cellular defense against oxidative stress and in the senescence of IMR-90 cells.

  18. MCPIP-1, alias Regnase-1 controls epithelial inflammation by post-transcriptional regulation of IL-8 production

    Science.gov (United States)

    Dobosz, E.; Wilamowski, M.; Lech, M.; Bugara, B.; Jura, J.; Potempa, J.; Koziel, J.

    2016-01-01

    Pattern recognition receptors are critical for the detection of invading microorganisms. They activate multiple pathways that lead to the induction of pro-inflammatory responses and pathogen clearance. The intensity and duration of this immune reaction must be tightly controlled spatially and temporally in every tissue by different negative regulators. We hypothesized that monocyte chemoattractant protein-1–induced protein-1 (MCPIP-1) might play a role in maintaining immune homeostasis in the epithelium both under physiological conditions and upon bacterial infection. To this end, we examined the distribution of MCPIP-1 transcript and protein in various tissues. The MCPIP-1 protein level was higher in epithelial cells than in myeloid cells. MCPIP-1 exerted RNase activity towards the IL-8 transcript and the life-span of IL-8 was determined by the presence of the stem-loops/hairpin (SL) structures at the 3′ UTR region of IL-8 mRNA. Moreover, using fully active, purified recombinant MCPIP-1 protein, we elucidated the mechanism by which MCPIP-1 controls the IL-8 mRNA level. In conclusion, we uncovered a novel IL-8–dependent mechanism via which MCPIP-1 maintains epithelial homeostasis. This study reveals for the first time that MCPIP-1 plays a crucial anti-inflammatory role not only in myeloid cells but also in epithelial cells. PMID:27513529

  19. Non-T cell activation linker (NTAL) negatively regulates TREM-1/DAP12-induced inflammatory cytokine production in myeloid cells

    Czech Academy of Sciences Publication Activity Database

    Tessarz, A.S.; Weiler, S.; Zanzinger, K.; Angelisová, Pavla; Hořejší, Václav; Cerwenka, A.

    2007-01-01

    Roč. 178, č. 4 (2007), s. 1991-1999 ISSN 0022-1767 R&D Projects: GA MŠk 1M0506 Institutional research plan: CEZ:AV0Z50520514 Keywords : NTAL * TREM-1 * cytokines Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.068, year: 2007

  20. Specific Inhibition of the VEGFR-3 Tyrosine Kinase by SAR131675 Reduces Peripheral and Tumor Associated Immunosuppressive Myeloid Cells

    International Nuclear Information System (INIS)

    Espagnolle, Nicolas; Barron, Pauline; Mandron, Marie; Blanc, Isabelle; Bonnin, Jacques; Agnel, Magali; Kerbelec, Erwan; Herault, Jean Pascal; Savi, Pierre; Bono, Françoise; Alam, Antoine

    2014-01-01

    Myeloid derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs) represent prominent components in cancer progression. We previously showed that inhibition of the VEGFR-3 pathway by SAR131675 leads to reduction of TAM infiltration and tumor growth. Here, we found that treatment with SAR131675 prevents the accumulation of immunosuppressive blood and splenic MDSCs which express VEGFR-3, in 4T1 tumor bearing mice. Moreover we showed that soluble factors secreted by tumor cells promote MDSCs proliferation and differentiation into M2 polarized F4/80+ macrophages. In addition, cell sorting and transcriptomic analysis of tumor infiltrating myeloid cells revealed the presence of a heterogeneous population that could be divided into 3 subpopulations: (i) immature cells with a MDSC phenotype (GR1+/CD11b+/F4/80 − ); (ii) “immuno-incompetent” macrophages (F4/80 high /CD86 neg /MHCII Low ) strongly expressing M2 markers such as Legumain, CD206 and Mgl1/2 and (iii) “immuno-competent”-M1 like macrophages (F4/80 Low /CD86 + /MHCII High ). SAR131675 treatment reduced MDSCs in lymphoid organs as well as F4/80 High populations in tumors. Interestingly, in the tumor SAR131675 was able to increase the immunocompetent M1 like population (F4/80 low ). Altogether these results demonstrate that the specific VEGFR-3 inhibitor SAR131675 exerts its anti tumoral activity by acting on different players that orchestrate immunosuppression and cancer progression in a tumoral context: MDSCs in peripheral lymphoid organs and TAMs infiltrating the tumor

  1. Specific Inhibition of the VEGFR-3 Tyrosine Kinase by SAR131675 Reduces Peripheral and Tumor Associated Immunosuppressive Myeloid Cells

    Energy Technology Data Exchange (ETDEWEB)

    Espagnolle, Nicolas [UMR5273 INSERM U1031/CNRS/EFS StromaLab, Toulouse 31432 (France); Barron, Pauline; Mandron, Marie; Blanc, Isabelle; Bonnin, Jacques [Sanofi Recherche et Développement, Early to Candidate DPU, Toulouse 31036 (France); Agnel, Magali; Kerbelec, Erwan [Molecular Biology Unit, Biologics Department, Sanofi, Vitry-sur-Seine 94400 (France); Herault, Jean Pascal; Savi, Pierre; Bono, Françoise; Alam, Antoine, E-mail: antoine.alam@sanofi.com [Sanofi Recherche et Développement, Early to Candidate DPU, Toulouse 31036 (France)

    2014-02-28

    Myeloid derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs) represent prominent components in cancer progression. We previously showed that inhibition of the VEGFR-3 pathway by SAR131675 leads to reduction of TAM infiltration and tumor growth. Here, we found that treatment with SAR131675 prevents the accumulation of immunosuppressive blood and splenic MDSCs which express VEGFR-3, in 4T1 tumor bearing mice. Moreover we showed that soluble factors secreted by tumor cells promote MDSCs proliferation and differentiation into M2 polarized F4/80+ macrophages. In addition, cell sorting and transcriptomic analysis of tumor infiltrating myeloid cells revealed the presence of a heterogeneous population that could be divided into 3 subpopulations: (i) immature cells with a MDSC phenotype (GR1+/CD11b+/F4/80{sup −}); (ii) “immuno-incompetent” macrophages (F4/80{sup high}/CD86{sup neg}/MHCII{sup Low}) strongly expressing M2 markers such as Legumain, CD206 and Mgl1/2 and (iii) “immuno-competent”-M1 like macrophages (F4/80{sup Low}/CD86{sup +}/MHCII{sup High}). SAR131675 treatment reduced MDSCs in lymphoid organs as well as F4/80{sup High} populations in tumors. Interestingly, in the tumor SAR131675 was able to increase the immunocompetent M1 like population (F4/80{sup low}). Altogether these results demonstrate that the specific VEGFR-3 inhibitor SAR131675 exerts its anti tumoral activity by acting on different players that orchestrate immunosuppression and cancer progression in a tumoral context: MDSCs in peripheral lymphoid organs and TAMs infiltrating the tumor.

  2. Unraveling the Molecular Mechanism of Benzothiophene and Benzofuran scaffold merged compounds binding to anti-apoptotic Myeloid cell leukemia 1.

    Science.gov (United States)

    Marimuthu, Parthiban; Singaravelu, Kalaimathy

    2018-05-10

    Myeloid cell leukemia 1 (Mcl1), is an anti-apoptotic member of the Bcl-2 family proteins, has gained considerable importance due to its overexpression activity prevents the oncogenic cells to undergo apoptosis. This overexpression activity of Mcl1 eventually develops strong resistance to a wide variety of anticancer agents. Therefore, designing novel inhibitors with potentials to elicit higher binding affinity and specificity to inhibit Mcl1 activity is of greater importance. Thus, Mcl1 acts as an attractive cancer target. Despite recent experimental advancement in the identification and characterization of Benzothiophene and Benzofuran scaffold merged compounds the molecular mechanisms of their binding to Mcl1 are yet to be explored. The current study demonstrates an integrated approach -pharmacophore-based 3D-QSAR, docking, Molecular Dynamics (MD) simulation and free-energy estimation- to access the precise and comprehensive effects of current inhibitors targeting Mcl1 together with its known activity values. The pharmacophore -ANRRR.240- based 3D-QSAR model from the current study provided high confidence (R 2 =0.9154, Q 2 =0.8736, and RMSE=0.3533) values. Furthermore, the docking correctly predicted the binding mode of highly active compound 42. Additionally, the MD simulation for docked complex under explicit-solvent conditions together with free-energy estimation exhibited stable interaction and binding strength over the time period. Also, the decomposition analysis revealed potential energy contributing residues -M231, M250, V253, R265, L267, and F270- to the complex stability. Overall, the current investigation might serve as a valuable insight, either to (i) improve the binding affinity of the current compounds or (ii) discover new generation anti-cancer agents that can effectively downregulate Mcl1 activity.

  3. Structural Basis for Bc12-Regulated Mitochondrion-Dependent Apoptosis

    National Research Council Canada - National Science Library

    Marassi, Francesca M

    2005-01-01

    ...; by dimerization with other Bcl-2 family members; by binding to other non-homologous proteins; and by formation of membrane pores that are believed to regulate apoptosis by perturbing mitochondrial physiology...

  4. Oxygen-dependent regulation of aquaporin-3 expression

    Directory of Open Access Journals (Sweden)

    Hoogewijs D

    2016-04-01

    Full Text Available David Hoogewijs,1,2 Melanie Vogler,3 Eveline Zwenger,3 Sabine Krull,3 Anke Zieseniss3 1Institute of Physiology, University of Duisburg-Essen, Essen, Germany; 2Institute of Physiology, University of Zürich, Zürich, Switzerland; 3Institute of Cardiovascular Physiology, University Medical Center Göttingen, University of Göttingen, Göttingen, GermanyAbstract: The purpose of this study was to investigate whether aquaporin-3 (AQP3 expression is altered in hypoxia and whether hypoxia-inducible transcription factor (HIF-1 regulates the hypoxic expression. AQP3 mRNA expression was studied in L929 fibrosarcoma cells and in several tissues derived from mice that were subjected to hypoxia. Computational analysis of the AQP3 promoter revealed conserved HIF binding sites within close proximity to the translational start site, and chromatin immunoprecipitation assays confirmed binding of HIF-1 to the endogenous hypoxia response elements. Furthermore, hypoxia resulted in increased expression of AQP3 mRNA in L929 fibrosarcoma cells. Consistently, shRNA-mediated knockdown of HIF-1 greatly reduced the hypoxic induction of AQP3. In addition, mRNA analysis of organs from mice exposed to inspiratory hypoxia demonstrated pronounced hypoxia-inducible expression of AQP3 in the kidney. Overall, our findings suggest that AQP3 expression can be regulated at the transcriptional level and that AQP3 represents a novel HIF-1 target gene. Keywords: transcriptional regulation, oxygen, hypoxia-inducible factor, hypoxia response element

  5. Card9-dependent IL-1β regulates IL-22 production from group 3 innate lymphoid cells and promotes colitis-associated cancer.

    Science.gov (United States)

    Bergmann, Hanna; Roth, Susanne; Pechloff, Konstanze; Kiss, Elina A; Kuhn, Sabine; Heikenwälder, Mathias; Diefenbach, Andreas; Greten, Florian R; Ruland, Jürgen

    2017-08-01

    Inflammatory bowel diseases (IBD) are key risk factors for the development of colorectal cancer, but the mechanisms that link intestinal inflammation with carcinogenesis are insufficiently understood. Card9 is a myeloid cell-specific signaling protein that regulates inflammatory responses downstream of various pattern recognition receptors and which cooperates with the inflammasomes for IL-1β production. Because polymorphisms in Card9 were recurrently associated with human IBD, we investigated the function of Card9 in a colitis-associated cancer (CAC) model. Card9 -/- mice develop smaller, less proliferative and less dysplastic tumors compared to their littermates and in the regenerating mucosa we detected dramatically impaired IL-1β generation and defective IL-1β controlled IL-22 production from group 3 innate lymphoid cells. Consistent with the key role of immune-derived IL-22 in activating STAT3 signaling during normal and pathological intestinal epithelial cell (IEC) proliferation, Card9 -/- mice also exhibit impaired tumor cell intrinsic STAT3 activation. Our results imply a Card9-controlled, ILC3-mediated mechanism regulating healthy and malignant IEC proliferation and demonstrates a role of Card9-mediated innate immunity in inflammation-associated carcinogenesis. © 2017 The Authors. European Journal of Immunology published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Exercise-Dependent Regulation of NK Cells in Cancer Protection

    DEFF Research Database (Denmark)

    Idorn, Manja; Hojman, Pernille

    2016-01-01

    Natural killer (NK) cells are the most responsive immune cells to exercise, displaying an acute mobilization to the circulation during physical exertion. Recently, exercise-dependent mobilization of NK cells was found to play a central role in exercise-mediated protection against cancer. Here, we...... a mechanistic explanation for the protective effect of exercise on cancer, and we propose that exercise represents a potential strategy as adjuvant therapy in cancer, by improving NK cell recruitment and infiltration in solid tumors....... review the link between exercise and NK cell function, focusing on circulating exercise factors and additional effects, including vascularization, hypoxia, and body temperature in mediating the effects on NK cell functionality. Exercise-dependent mobilization and activation of NK cells provides...

  7. Intracellular calcium levels can regulate Importin-dependent nuclear import

    International Nuclear Information System (INIS)

    Kaur, Gurpreet; Ly-Huynh, Jennifer D.; Jans, David A.

    2014-01-01

    Highlights: • High intracellular calcium inhibits Impα/β1- or Impβ1-dependent nuclear protein import. • The effect of Ca 2+ on nuclear import does not relate to changes in the nuclear pore. • High intracellular calcium can result in mislocalisation of Impβ1, Ran and RCC1. - Abstract: We previously showed that increased intracellular calcium can modulate Importin (Imp)β1-dependent nuclear import of SRY-related chromatin remodeling proteins. Here we extend this work to show for the first time that high intracellular calcium inhibits Impα/β1- or Impβ1-dependent nuclear protein import generally. The basis of this relates to the mislocalisation of the transport factors Impβ1 and Ran, which show significantly higher nuclear localization in contrast to various other factors, and RCC1, which shows altered subnuclear localisation. The results here establish for the first time that intracellular calcium modulates conventional nuclear import through direct effects on the nuclear transport machinery

  8. Intracellular calcium levels can regulate Importin-dependent nuclear import

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Gurpreet; Ly-Huynh, Jennifer D.; Jans, David A., E-mail: David.Jans@monash.edu

    2014-07-18

    Highlights: • High intracellular calcium inhibits Impα/β1- or Impβ1-dependent nuclear protein import. • The effect of Ca{sup 2+} on nuclear import does not relate to changes in the nuclear pore. • High intracellular calcium can result in mislocalisation of Impβ1, Ran and RCC1. - Abstract: We previously showed that increased intracellular calcium can modulate Importin (Imp)β1-dependent nuclear import of SRY-related chromatin remodeling proteins. Here we extend this work to show for the first time that high intracellular calcium inhibits Impα/β1- or Impβ1-dependent nuclear protein import generally. The basis of this relates to the mislocalisation of the transport factors Impβ1 and Ran, which show significantly higher nuclear localization in contrast to various other factors, and RCC1, which shows altered subnuclear localisation. The results here establish for the first time that intracellular calcium modulates conventional nuclear import through direct effects on the nuclear transport machinery.

  9. Insights into Cdc13 Dependent Telomere Length Regulation

    Energy Technology Data Exchange (ETDEWEB)

    M Mason; E Skordalakes

    2011-12-31

    Cdc13 is a single stranded telomere binding protein that specifically localizes to the telomere ends of budding yeasts and is essential for cell viability. It caps the ends of chromosomes thus preventing chromosome end-to-end fusions and exonucleolytic degradation, events that could lead to genomic instability and senescence, the hallmark of aging. Cdc13 is also involved in telomere length regulation by recruiting or preventing access of telomerase to the telomeric overhang. Recruitment of telomerase to the telomeres for G-strand extension is required for continuous cell division, while preventing its access to the telomeres through capping the chromosome ends prevents mitotic events that could lead to cell immortality, the hall mark of carcinogenesis. Cdc13 and its putative homologues human CTC1 and POT1 are therefore key to many biological processes directly associated with life extension and cancer prevention and can be viewed as an ideal target for cancer and age related therapies.

  10. Activation of liver X receptor decreases atherosclerosis in Ldlr⁻/⁻ mice in the absence of ATP-binding cassette transporters A1 and G1 in myeloid cells

    NARCIS (Netherlands)

    Kappus, Mojdeh S.; Murphy, Andrew J.; Abramowicz, Sandra; Ntonga, Vusisizwe; Welch, Carrie L.; Tall, Alan R.; Westerterp, Marit

    2014-01-01

    Liver X receptor (LXR) activators decrease atherosclerosis in mice. LXR activators (1) directly upregulate genes involved in reverse cholesterol transport and (2) exert anti-inflammatory effects mediated by transrepression of nuclear factor-κB target genes. We investigated whether myeloid cell

  11. Regulation of potassium dependent ATPase (kdp) operon of Deinococcus radiodurans.

    Science.gov (United States)

    Dani, Pratiksha; Ujaoney, Aman Kumar; Apte, Shree Kumar; Basu, Bhakti

    2017-01-01

    The genome of D. radiodurans harbors genes for structural and regulatory proteins of Kdp ATPase, in an operon pattern, on Mega plasmid 1. Organization of its two-component regulatory genes is unique. Here we demonstrate that both, the structural as well as regulatory components of the kdp operon of D. radiodurans are expressed quickly as the cells experience potassium limitation but are not expressed upon increase in osmolarity. The cognate DNA binding response regulator (RR) effects the expression of kdp operon during potassium deficiency through specific interaction with the kdp promoter. Deletion of the gene encoding RR protein renders the mutant D. radiodurans (ΔRR) unable to express kdp operon under potassium limitation. The ΔRR D. radiodurans displays no growth defect when grown on rich media or when exposed to oxidative or heat stress but shows reduced growth following gamma irradiation. The study elucidates the functional and regulatory aspects of the novel kdp operon of this extremophile, for the first time.

  12. Glutathionylation regulates cytosolic NADP+-dependent isocitrate dehydrogenase activity.

    Science.gov (United States)

    Shin, Seoung Woo; Oh, Chang Joo; Kil, In Sup; Park, Jeen-Woo

    2009-04-01

    Cytosolic NADP+-dependent isocitrate dehydrogenase (IDPc) is susceptible to inactivation by numerous thiol-modifying reagents. This study now reports that Cys269 of IDPc is a target for S-glutathionylation and that this modification is reversed by dithiothreitol as well as enzymatically by cytosolic glutaredoxin in the presence of GSH. Glutathionylated IDPc was significantly less susceptible than native protein to peptide fragmentation by reactive oxygen species and proteolytic digestion. Glutathionylation may play a protective role in the degradation of protein through the structural alterations of IDPc. HEK293 cells treated with diamide displayed decreased IDPc activity and accumulated glutathionylated enzyme. Using immunoprecipitation with an anti-IDPc IgG and immunoblotting with an anti-GSH IgG, we purified and positively identified glutathionylated IDPc from the kidneys of mice subjected to ischemia/reperfusion injury and from the livers of ethanol-administered rats. These results suggest that IDPc activity is modulated through enzymatic glutathionylation and deglutathionylation during oxidative stress.

  13. Vasotrophic Regulation of Age-Dependent Hypoxic Cerebrovascular Remodeling

    Science.gov (United States)

    Silpanisong, Jinjutha; Pearce, William J.

    2015-01-01

    Hypoxia can induce functional and structural vascular remodeling by changing the expression of trophic factors to promote homeostasis. While most experimental approaches have been focused on functional remodeling, structural remodeling can reflect changes in the abundance and organization of vascular proteins that determine functional remodeling. Better understanding of age-dependent hypoxic macrovascular remodeling processes of the cerebral vasculature and its clinical implications require knowledge of the vasotrophic factors that influence arterial structure and function. Hypoxia can affect the expression of transcription factors, classical receptor tyrosine kinase factors, non-classical G-protein coupled factors, catecholamines, and purines. Hypoxia’s remodeling effects can be mediated by Hypoxia Inducible Factor (HIF) upregulation in most vascular beds, but alterations in the expression of growth factors can also be independent of HIF. PPARγ is another transcription factor involved in hypoxic remodeling. Expression of classical receptor tyrosine kinase ligands, including vascular endothelial growth factor, platelet derived growth factor, fibroblast growth factor and angiopoietins, can be altered by hypoxia which can act simultaneously to affect remodeling. Tyrosine kinase-independent factors, such as transforming growth factor, nitric oxide, endothelin, angiotensin II, catecholamines, and purines also participate in the remodeling process. This adaptation to hypoxic stress can fundamentally change with age, resulting in different responses between fetuses and adults. Overall, these mechanisms integrate to assure that blood flow and metabolic demand are closely matched in all vascular beds and emphasize the view that the vascular wall is a highly dynamic and heterogeneous tissue with multiple cell types undergoing regular phenotypic transformation. PMID:24063376

  14. Regulation of gene expression in Streptococcus pneumoniae by response regulator 09 is strain dependent

    NARCIS (Netherlands)

    W.T. Hendriksen (Wouter); N. Silva (Nuno); H.J. Bootsma (Hester); C.E. Blue (Clare); G.K. Paterson (Gavin); A.R. Kerr (Alison); A.S. de Jong (Arjan); O.P. Kuipers (Oscar); P.W.M. Hermans (Peter); T.J. Mitchell

    2007-01-01

    textabstractRecent murine studies have demonstrated that the role of response regulator 09 (RR09) of Streptococcus pneumoniae in virulence is different in different strains. In the present study, we used a murine pneumonia model of infection to assess the virulence of a TIGR4 rr09 mutant, and we

  15. Regulation of gene expression in Streptococcus pneumoniae by response regulator 09 is strain dependent

    NARCIS (Netherlands)

    Hendriksen, Wouter T.; Silva, Nuno; Bootsma, Hester J.; Blue, Clare E.; Paterson, Gavin K.; Kerr, Alison R.; de Jong, Anne; Kuipers, Oscar P.; Hermans, Peter W. M.; Mitchell, Tim J.

    Recent murine studies have demonstrated that the role of response regulator 09 (RR09) of Streptococcus pneumoniae in virulence is different in different strains. In the present study, we used a murine pneumonia model of infection to assess the virulence of a TIGR4 rr09 mutant, and we found that

  16. Large-Scale Phosphoproteomics Reveals Shp-2 Phosphatase-Dependent Regulators of Pdgf Receptor Signaling

    DEFF Research Database (Denmark)

    Batth, Tanveer S; Papetti, Moreno; Pfeiffer, Anamarija

    2018-01-01

    Despite its low cellular abundance, phosphotyrosine (pTyr) regulates numerous cell signaling pathways in health and disease. We applied comprehensive phosphoproteomics to unravel differential regulators of receptor tyrosine kinase (RTK)-initiated signaling networks upon activation by Pdgf-ββ, Fgf-2...... of Pdgfr pTyr signaling. Application of a recently introduced allosteric Shp-2 inhibitor revealed global regulation of the Pdgf-dependent tyrosine phosphoproteome, which significantly impaired cell migration. In addition, we present a list of hundreds of Shp-2-dependent targets and putative substrates...

  17. Negative regulation of quorum-sensing systems in Pseudomonas aeruginosa by ATP-dependent Lon protease.

    Science.gov (United States)

    Takaya, Akiko; Tabuchi, Fumiaki; Tsuchiya, Hiroko; Isogai, Emiko; Yamamoto, Tomoko

    2008-06-01

    Lon protease, a member of the ATP-dependent protease family, regulates numerous cellular systems by degrading specific substrates. Here, we demonstrate that Lon is involved in the regulation of quorum-sensing (QS) signaling systems in Pseudomonas aeruginosa, an opportunistic human pathogen. The organism has two acyl-homoserine lactone (HSL)-mediated QS systems, LasR/LasI and RhlR/RhlI. Many reports have demonstrated that these two systems are regulated and interconnected by global regulators. We found that lon-disrupted cells overproduce pyocyanin, the biosynthesis of which depends on the RhlR/RhlI system, and show increased levels of a transcriptional regulator, RhlR. The QS systems are organized hierarchically: the RhlR/RhlI system is subordinate to LasR/LasI. To elucidate the mechanism by which Lon negatively regulates RhlR/RhlI, we examined the effect of lon disruption on the LasR/LasI system. We found that Lon represses the expression of LasR/LasI by degrading LasI, an HSL synthase, leading to negative regulation of the RhlR/RhlI system. RhlR/RhlI was also shown to be regulated by Lon independently of LasR/LasI via regulation of RhlI, an HSL synthase. In view of these findings, it is suggested that Lon protease is a powerful negative regulator of both HSL-mediated QS systems in P. aeruginosa.

  18. Context-dependent interactions and the regulation of species richness in freshwater fish

    Science.gov (United States)

    MacDougall, Andrew S.; Harvey, Eric; McCune, Jenny L.; Nilsson, Karin A.; Bennett, Joseph; Firn, Jennifer; Bartley, Timothy; Grace, James B.; Kelly, Jocelyn; Tunney, Tyler D.; McMeans, Bailey; Matsuzaki, Shin-Ichiro S.; Kadoya, Taku; Esch, Ellen; Cazelles, Kevin; Lester, Nigel; McCann, Kevin S.

    2018-01-01

    Species richness is regulated by a complex network of scale-dependent processes. This complexity can obscure the influence of limiting species interactions, making it difficult to determine if abiotic or biotic drivers are more predominant regulators of richness. Using integrative modeling of freshwater fish richness from 721 lakes along an 11olatitudinal gradient, we find negative interactions to be a relatively minor independent predictor of species richness in lakes despite the widespread presence of predators. Instead, interaction effects, when detectable among major functional groups and 231 species pairs, were strong, often positive, but contextually dependent on environment. These results are consistent with the idea that negative interactions internally structure lake communities but do not consistently ‘scale-up’ to regulate richness independently of the environment. The importance of environment for interaction outcomes and its role in the regulation of species richness highlights the potential sensitivity of fish communities to the environmental changes affecting lakes globally.

  19. Differential contribution of complement receptor C5aR in myeloid and non-myeloid cells in chronic ethanol-induced liver injury in mice.

    Science.gov (United States)

    McCullough, Rebecca L; McMullen, Megan R; Das, Dola; Roychowdhury, Sanjoy; Strainic, Michael G; Medof, M Edward; Nagy, Laura E

    2016-07-01

    Complement is implicated in the development of alcoholic liver disease. C3 and C5 contribute to ethanol-induced liver injury; however, the role of C5a receptor (C5aR) on myeloid and non-myeloid cells to progression of injury is not known. C57BL/6 (WT), global C5aR-/-, myeloid-specific C5aR-/-, and non-myeloid-specific C5aR-/- mice were fed a Lieber-DeCarli diet (32%kcal EtOH) for 25 days. Cultured hepatocytes were challenged with ethanol, TNFα, and C5a. Chronic ethanol feeding increased expression of pro-inflammatory mediators in livers of WT mice; this response was completely blunted in C5aR-/- mice. However, C5aR-/- mice were not protected from other measures of hepatocellular damage, including ethanol-induced increases in hepatic triglycerides, plasma alanine aminotransferase and hepatocyte apoptosis. CYP2E1 and 4-hydroxynonenal protein adducts were induced in WT and C5aR-/- mice. Myeloid-specific C5aR-/- mice were protected from ethanol-induced increases in hepatic TNFα, whereas non-myeloid-specific C5aR-/- displayed increased hepatocyte apoptosis and inflammation after chronic ethanol feeding. In cultured hepatocytes, cytotoxicity induced by challenge with ethanol and TNFα was completely eliminated by treatment with C5a in cells from WT, but not C5aR-/- mice. Further, treatment with C5a enhanced activation of pro-survival signal AKT in hepatocytes challenged with ethanol and TNFα. Taken together, these data reveal a differential role for C5aR during ethanol-induced liver inflammation and injury, with C5aR on myeloid cells contributing to ethanol-induced inflammatory cytokine expression, while non-myeloid C5aR protects hepatocytes from death after chronic ethanol feeding. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Time-dependent, glucose-regulated Arabidopsis Regulator of G-protein Signaling 1 network

    Directory of Open Access Journals (Sweden)

    Dinesh Kumar Jaiswal

    2016-04-01

    Full Text Available Plants lack 7-transmembrane, G-protein coupled receptors (GPCRs because the G alpha subunit of the heterotrimeric G protein complex is “self-activating”—meaning that it spontaneously exchanges bound GDP for GTP without the need of a GPCR. In lieu of GPCRs, most plants have a seven transmembrane receptor-like regulator of G-protein signaling (RGS protein, a component of the complex that keeps G-protein signaling in its non-activated state. The addition of glucose physically uncouples AtRGS1 from the complex through specific endocytosis leaving the activated G protein at the plasma membrane. The complement of proteins in the AtRGS1/G-protein complex over time from glucose-induced endocytosis was profiled by immunoprecipitation coupled to mass spectrometry (IP-MS. A total of 119 proteins in the AtRGS1 complex were identified. Several known interactors of the complex were identified, thus validating the approach, but the vast majority (93/119 were not known previously. AtRGS1 protein interactions were dynamically modulated by d-glucose. At low glucose levels, the AtRGS1 complex is comprised of proteins involved in transport, stress and metabolism. After glucose application, the AtRGS1 complex rapidly sheds many of these proteins and recruits other proteins involved in vesicular trafficking and signal transduction. The profile of the AtRGS1 components answers several questions about the type of coat protein and vesicular trafficking GTPases used in AtRGS1 endocytosis and the function of endocytic AtRGS1.

  1. G-CSF/anti-G-CSF antibody complexes drive the potent recovery and expansion of CD11b+Gr-1+ myeloid cells without compromising CD8+ T cell immune responses

    Science.gov (United States)

    2013-01-01

    Background Administration of recombinant G-CSF following cytoreductive therapy enhances the recovery of myeloid cells, minimizing the risk of opportunistic infection. Free G-CSF, however, is expensive, exhibits a short half-life, and has poor biological activity in vivo. Methods We evaluated whether the biological activity of G-CSF could be improved by pre-association with anti-G-CSF mAb prior to injection into mice. Results We find that the efficacy of G-CSF therapy can be enhanced more than 100-fold by pre-association of G-CSF with an anti-G-CSF monoclonal antibody (mAb). Compared with G-CSF alone, administration of G-CSF/anti-G-CSF mAb complexes induced the potent expansion of CD11b+Gr-1+ myeloid cells in mice with or without concomitant cytoreductive treatment including radiation or chemotherapy. Despite driving the dramatic expansion of myeloid cells, in vivo antigen-specific CD8+ T cell immune responses were not compromised. Furthermore, injection of G-CSF/anti-G-CSF mAb complexes heightened protective immunity to bacterial infection. As a measure of clinical value, we also found that antibody complexes improved G-CSF biological activity much more significantly than pegylation. Conclusions Our findings provide the first evidence that antibody cytokine complexes can effectively expand myeloid cells, and furthermore, that G-CSF/anti-G-CSF mAb complexes may provide an improved method for the administration of recombinant G-CSF. PMID:24279871

  2. Nuclear cGMP-dependent kinase regulates gene expression via activity-dependent recruitment of a conserved histone deacetylase complex.

    Directory of Open Access Journals (Sweden)

    Yan Hao

    2011-05-01

    Full Text Available Elevation of the second messenger cGMP by nitric oxide (NO activates the cGMP-dependent protein kinase PKG, which is key in regulating cardiovascular, intestinal, and neuronal functions in mammals. The NO-cGMP-PKG signaling pathway is also a major therapeutic target for cardiovascular and male reproductive diseases. Despite widespread effects of PKG activation, few molecular targets of PKG are known. We study how EGL-4, the Caenorhabditis elegans PKG ortholog, modulates foraging behavior and egg-laying and seeks the downstream effectors of EGL-4 activity. Using a combination of unbiased forward genetic screen and proteomic analysis, we have identified a conserved SAEG-1/SAEG-2/HDA-2 histone deacetylase complex that is specifically recruited by activated nuclear EGL-4. Gene expression profiling by microarrays revealed >40 genes that are sensitive to EGL-4 activity in a SAEG-1-dependent manner. We present evidence that EGL-4 controls egg laying via one of these genes, Y45F10C.2, which encodes a novel protein that is expressed exclusively in the uterine epithelium. Our results indicate that, in addition to cytoplasmic functions, active EGL-4/PKG acts in the nucleus via a conserved Class I histone deacetylase complex to regulate gene expression pertinent to behavioral and physiological responses to cGMP. We also identify transcriptional targets of EGL-4 that carry out discrete components of the physiological response.

  3. Comprehensive analysis of PPARα-dependent regulation of hepatic lipid metabolism by expression profiling - 5

    NARCIS (Netherlands)

    Rakhshandehroo, Maryam; Sanderson-Kjellberg, L.M.; Matilainen, Merja; Stienstra, Rinke; Carlberg, Carsten; Groot, de Philip; Muller, Michael; Kersten, Sander

    2007-01-01

    PPARα is a ligand-activated transcription factor involved in the regulation of nutrient metabolism and inflammation. Although much is already known about the function of PPARα in hepatic lipid metabolism, many PPARα-dependent pathways and genes have yet to be discovered. In order to obtain an

  4. Comprehensive analysis of PPARa-dependent regulation of hepatic lipid metabolism by expression profiling

    NARCIS (Netherlands)

    Rakhshandehroo, Maryam; Sanderson-Kjellberg, L.M.; Matilainen, Merja; Stienstra, Rinke; Carlberg, Carsten; Groot, de Philip; Muller, Michael; Kersten, Sander

    2007-01-01

    PPARalpha is a ligand-activated transcription factor involved in the regulation of nutrient metabolism and inflammation. Although much is already known about the function of PPARalpha in hepatic lipid metabolism, many PPARalpha-dependent pathways and genes have yet to be discovered. In order to

  5. Herp regulates Hrd1-mediated ubiquitylation in a ubiquitin-like domain-dependent manner

    DEFF Research Database (Denmark)

    Kny, Melanie; Standera, Sybille; Hartmann-Petersen, Rasmus

    2011-01-01

    in ER-associated protein degradation (ERAD) and interacts directly with the ubiquitin ligase Hrd1, which is found in high molecular mass complexes of the ER membrane. Here we present the first evidence that Herp regulates Hrd1-mediated ubiquitylation in a ubiquitin-like (UBL) domain-dependent manner. We...

  6. Regulators of cyclin-dependent kinases are crucial for maintaining genome integrity in S phase

    DEFF Research Database (Denmark)

    Beck, Halfdan; Nähse, Viola; Larsen, Marie Sofie Yoo

    2010-01-01

    are important negative regulators of CDK1 and -2. Strikingly, WEE1 depletion rapidly induced DNA damage in S phase in newly replicated DNA, which was accompanied by a marked increase in single-stranded DNA. This DNA damage is dependent on CDK1 and -2 as well as the replication proteins MCM2 and CDT1 but not CDC...

  7. Phosphorylation of linker histones regulates ATP-dependent chromatin remodeling enzymes.

    NARCIS (Netherlands)

    Horn, P.J.; Carruthers, L.M.; Logie, C.; Hill, D.A.; Solomon, M.J.; Wade, P.A.; Imbalzano, A.N.; Hansen, J.; Peterson, C.L.

    2002-01-01

    Members of the ATP-dependent family of chromatin remodeling enzymes play key roles in the regulation of transcription, development, DNA repair and cell cycle control. We find that the remodeling activities of the ySWI/SNF, hSWI/SNF, xMi-2 and xACF complexes are nearly abolished by incorporation of

  8. Explaining density-dependent regulation in earthworm populations using life-history analysis

    NARCIS (Netherlands)

    Kammenga, J.E.; Spurgeon, D.J.; Svendsen, C.; Weeks, J.M.

    2003-01-01

    At present there is little knowledge about how density regulates population growth rate and to what extent this is determined by life-history patterns. We compared density dependent population consequences in the Nicholsonian sense based oil experimental observations and life-history modeling for

  9. Blimp-1-Dependent IL-10 Production by Tr1 Cells Regulates TNF-Mediated Tissue Pathology.

    Directory of Open Access Journals (Sweden)

    Marcela Montes de Oca

    2016-01-01

    Full Text Available Tumor necrosis factor (TNF is critical for controlling many intracellular infections, but can also contribute to inflammation. It can promote the destruction of important cell populations and trigger dramatic tissue remodeling following establishment of chronic disease. Therefore, a better understanding of TNF regulation is needed to allow pathogen control without causing or exacerbating disease. IL-10 is an important regulatory cytokine with broad activities, including the suppression of inflammation. IL-10 is produced by different immune cells; however, its regulation and function appears to be cell-specific and context-dependent. Recently, IL-10 produced by Th1 (Tr1 cells was shown to protect host tissues from inflammation induced following infection. Here, we identify a novel pathway of TNF regulation by IL-10 from Tr1 cells during parasitic infection. We report elevated Blimp-1 mRNA levels in CD4+ T cells from visceral leishmaniasis (VL patients, and demonstrate IL-12 was essential for Blimp-1 expression and Tr1 cell development in experimental VL. Critically, we show Blimp-1-dependent IL-10 production by Tr1 cells prevents tissue damage caused by IFNγ-dependent TNF production. Therefore, we identify Blimp-1-dependent IL-10 produced by Tr1 cells as a key regulator of TNF-mediated pathology and identify Tr1 cells as potential therapeutic tools to control inflammation.

  10. Diagnostic Performance of Soluble Triggering Receptor Expressed on Myeloid Cells-1 in Ventilator-Associated Pneumonia of Patients with Ischemic Stroke.

    Science.gov (United States)

    Yu, Yuetian; Zhu, Cheng; Liu, Chunyan; Gao, Yuan; Yin, Rong; Cao, Jianguo

    2017-01-01

    Objective . To investigate the effect of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) in serum, bronchoalveolar lavage fluid (BALF), endotracheal aspiration (ETA), and exhaled breath condensate (EBC) samples as early biomarkers for the diagnosis of ventilator-associated pneumonia (VAP) in patients with ischemic stroke. Methods . One hundred and thirty-two patients with clinically suspected VAP were enrolled in this study. Bronchoscopy was performed on the day of clinically suspected VAP. sTREM-1 levels in serum, BALF, ETA, and EBC were measured. VAP was diagnosed by quantitative cultures of BALF (≥10 4  cfu/mL). Results . VAP was confirmed in 76 (57.58%) cases. Patients with VAP showed significantly higher sTREM-1 in BALF [32.35 (IQR, 30.08-41.72) versus 18.92 (11.89-31.72)] pg/mL and in EBC [1.57 (IQR, 1.02-2.61) versus 0.41 (0.19-1.61)] pg/mL than patients without VAP. The area under the curve was 0.813 ( p VAP.

  11. Selective blockade of B7-H3 enhances antitumour immune activity by reducing immature myeloid cells in head and neck squamous cell carcinoma.

    Science.gov (United States)

    Mao, Liang; Fan, Teng-Fei; Wu, Lei; Yu, Guang-Tao; Deng, Wei-Wei; Chen, Lei; Bu, Lin-Lin; Ma, Si-Rui; Liu, Bing; Bian, Yansong; Kulkarni, Ashok B; Zhang, Wen-Feng; Sun, Zhi-Jun

    2017-09-01

    Immature myeloid cells including myeloid-derived suppressor cells (MDSCs) and tumour-associated macrophages (TAMs) promote tumour growth and metastasis by facilitating tumour transformation and angiogenesis, as well as by suppressing antitumour effector immune responses. Therefore, strategies designed to reduce MDSCs and TAMs accumulation and their activities are potentially valuable therapeutic goals. In this study, we show that negative immune checkpoint molecule B7-H3 is significantly overexpressed in human head and neck squamous cell carcinoma (HNSCC) specimen as compared with normal oral mucosa. Using immunocompetent transgenic HNSCC models, we observed that targeting inhibition of B7-H3 reduced tumour size. Flow cytometry analysis revealed that targeting inhibition of B7-H3 increases antitumour immune response by decreasing immunosuppressive cells and promoting cytotoxic T cell activation in both tumour microenvironment and macroenvironment. Our study provides direct in vivo evidence for a rationale for B7-H3 blockade as a future therapeutic strategy to treat patients with HNSCC. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  12. Mac-1low early myeloid cells in the bone marrow-derived SP fraction migrate into injured skeletal muscle and participate in muscle regeneration

    International Nuclear Information System (INIS)

    Ojima, Koichi; Uezumi, Akiyoshi; Miyoshi, Hiroyuki; Masuda, Satoru; Morita, Yohei; Fukase, Akiko; Hattori, Akihito; Nakauchi, Hiromitsu; Miyagoe-Suzuki, Yuko; Takeda, Shin'ichi

    2004-01-01

    Recent studies have shown that bone marrow (BM) cells, including the BM side population (BM-SP) cells that enrich hematopoietic stem cells (HSCs), are incorporated into skeletal muscle during regeneration, but it is not clear how and what kinds of BM cells contribute to muscle fiber regeneration. We found that a large number of SP cells migrated from BM to muscles following injury in BM-transplanted mice. These BM-derived SP cells in regenerating muscles expressed different surface markers from those of HSCs and could not reconstitute the mouse blood system. BM-derived SP/Mac-1 low cells increased in number in regenerating muscles following injury. Importantly, our co-culture studies with activated satellite cells revealed that this fraction carried significant potential for myogenic differentiation. By contrast, mature inflammatory (Mac-1 high ) cells showed negligible myogenic activities. Further, these BM-derived SP/Mac-1 low cells gave rise to mononucleate myocytes, indicating that their myogenesis was not caused by stochastic fusion with host myogenic cells, although they required cell-to-cell contact with myogenic cells for muscle differentiation. Taken together, our data suggest that neither HSCs nor mature inflammatory cells, but Mac-1 low early myeloid cells in the BM-derived SP fraction, play an important role in regenerating skeletal muscles

  13. Relationships between High-mobility Group Protein B1 and Triggering Receptor Expressed on Myeloid Cells Concentrations in Gingival Crevicular Fluid and Chronic Periodontitis.

    Science.gov (United States)

    Paknejad, Mojgan; Sattari, Mandana; Roozbahani, Zohreh; Ershadi, Morteza; Mehrfard, Ali

    2016-10-01

    One of the inflammatory mediators which is secreted by inflammatory cells is high-mobility group protein B1 (HMGB1). Interaction of HMGB1 and toll-like receptors (TLRs) leads to increased production of inflammatory cytokines. On the other hand, it was shown that triggering receptor expressed on myeloid cells (TREM-1) also can be activated by TLRs, and its soluble form (sTREM-1) can be formed by cleaving of membrane-bound form of TREM-1 proteinases. Since there is not enough knowledge about the precise role of HMGB1 and sTREM-1 in periodontal diseases, the aim of this study was to evaluate the concentration of HMGB1 and sTREM-1 in gingival crevicular fluid (GCF) samples of patients with chronic periodontitis. Gingival crevicular fluid (GCF) samples were obtained from a total of 24 individuals with clinically healthy gingiva and 24 patients with moderate to severe chronic periodontitis. For collecting GCF samples, periopapers were placed at the entrance of the crevice and left in position for 30 seconds. Then, they were stored at -80°C. Enzyme-linked immunosorbent assay (ELISA) was used for measuring the concentration of HMGB1 and sTREM-1 in GCF samples. The concentration of HMGB1 (pchronic periodontitis group. In addition, there was a significant positive correlation between HMGB1 and sTREM-1 concentration in chronic periodontitis group (pperiodontal tissues and they can promote inflammatory process, which leads to tissue destruction.

  14. Size-Dependent Regulation of Intracellular Trafficking of Polystyrene Nanoparticle-Based Drug-Delivery Systems.

    Science.gov (United States)

    Wang, Ting; Wang, Lu; Li, Xiaoming; Hu, Xingjie; Han, Yuping; Luo, Yao; Wang, Zejun; Li, Qian; Aldalbahi, Ali; Wang, Lihua; Song, Shiping; Fan, Chunhai; Zhao, Yun; Wang, Maolin; Chen, Nan

    2017-06-07

    Nanoparticles (NPs) have shown great promise as intracellular imaging probes or nanocarriers and are increasingly being used in biomedical applications. A detailed understanding of how NPs get "in and out" of cells is important for developing new nanomaterials with improved selectivity and less cytotoxicity. Both physical and chemical characteristics have been proven to regulate the cellular uptake of NPs. However, the exocytosis process and its regulation are less explored. Herein, we investigated the size-regulated endocytosis and exocytosis of carboxylated polystyrene (PS) NPs. PS NPs with a smaller size were endocytosed mainly through the clathrin-dependent pathway, whereas PS NPs with a larger size preferred caveolae-mediated endocytosis. Furthermore, our results revealed exocytosis of larger PS NPs and tracked the dynamic process at the single-particle level. These results indicate that particle size is a key factor for the regulation of intracellular trafficking of NPs and provide new insight into the development of more effective cellular nanocarriers.

  15. Phosphorylation-dependent regulation of plant chromatin and chromatin-associated proteins

    KAUST Repository

    Bigeard, Jean; Rayapuram, Naganand; Pflieger, Delphine; Hirt, Heribert

    2014-01-01

    In eukaryotes, most of the DNA is located in the nucleus where it is organized with histone proteins in a higher order structure as chromatin. Chromatin and chromatin-associated proteins contribute to DNA-related processes such as replication and transcription as well as epigenetic regulation. Protein functions are often regulated by PTMs among which phosphorylation is one of the most abundant PTM. Phosphorylation of proteins affects important properties, such as enzyme activity, protein stability, or subcellular localization. We here describe the main specificities of protein phosphorylation in plants and review the current knowledge on phosphorylation-dependent regulation of plant chromatin and chromatin-associated proteins. We also outline some future challenges to further elucidate protein phosphorylation and chromatin regulation.

  16. Phosphorylation-dependent regulation of plant chromatin and chromatin-associated proteins

    KAUST Repository

    Bigeard, Jean

    2014-07-10

    In eukaryotes, most of the DNA is located in the nucleus where it is organized with histone proteins in a higher order structure as chromatin. Chromatin and chromatin-associated proteins contribute to DNA-related processes such as replication and transcription as well as epigenetic regulation. Protein functions are often regulated by PTMs among which phosphorylation is one of the most abundant PTM. Phosphorylation of proteins affects important properties, such as enzyme activity, protein stability, or subcellular localization. We here describe the main specificities of protein phosphorylation in plants and review the current knowledge on phosphorylation-dependent regulation of plant chromatin and chromatin-associated proteins. We also outline some future challenges to further elucidate protein phosphorylation and chromatin regulation.

  17. The transcription factor ABI4 Is required for the ascorbic acid-dependent regulation of growth and regulation of jasmonate-dependent defense signaling pathways in Arabidopsis.

    Science.gov (United States)

    Kerchev, Pavel I; Pellny, Till K; Vivancos, Pedro Diaz; Kiddle, Guy; Hedden, Peter; Driscoll, Simon; Vanacker, Hélène; Verrier, Paul; Hancock, Robert D; Foyer, Christine H

    2011-09-01

    Cellular redox homeostasis is a hub for signal integration. Interactions between redox metabolism and the ABSCISIC ACID-INSENSITIVE-4 (ABI4) transcription factor were characterized in the Arabidopsis thaliana vitamin c defective1 (vtc1) and vtc2 mutants, which are defective in ascorbic acid synthesis and show a slow growth phenotype together with enhanced abscisic acid (ABA) levels relative to the wild type (Columbia-0). The 75% decrease in the leaf ascorbate pool in the vtc2 mutants was not sufficient to adversely affect GA metabolism. The transcriptome signatures of the abi4, vtc1, and vtc2 mutants showed significant overlap, with a large number of transcription factors or signaling components similarly repressed or induced. Moreover, lincomycin-dependent changes in LIGHT HARVESTING CHLOROPHYLL A/B BINDING PROTEIN 1.1 expression were comparable in these mutants, suggesting overlapping participation in chloroplast to nucleus signaling. The slow growth phenotype of vtc2 was absent in the abi4 vtc2 double mutant, as was the sugar-insensitive phenotype of the abi4 mutant. Octadecanoid derivative-responsive AP2/ERF-domain transcription factor 47 (ORA47) and AP3 (an ABI5 binding factor) transcripts were enhanced in vtc2 but repressed in abi4 vtc2, suggesting that ABI4 and ascorbate modulate growth and defense gene expression through jasmonate signaling. We conclude that low ascorbate triggers ABA- and jasmonate-dependent signaling pathways that together regulate growth through ABI4. Moreover, cellular redox homeostasis exerts a strong influence on sugar-dependent growth regulation.

  18. Carbon dioxide-dependent regulation of NF-κB family members RelB and p100 gives molecular insight into CO2-dependent immune regulation.

    Science.gov (United States)

    Keogh, Ciara E; Scholz, Carsten C; Rodriguez, Javier; Selfridge, Andrew C; von Kriegsheim, Alexander; Cummins, Eoin P

    2017-07-07

    CO 2 is a physiological gas normally produced in the body during aerobic respiration. Hypercapnia (elevated blood pCO 2 >≈50 mm Hg) is a feature of several lung pathologies, e.g. chronic obstructive pulmonary disease. Hypercapnia is associated with increased susceptibility to bacterial infections and suppression of inflammatory signaling. The NF-κB pathway has been implicated in these effects; however, the molecular mechanisms underpinning cellular sensitivity of the NF-κB pathway to CO 2 are not fully elucidated. Here, we identify several novel CO 2 -dependent changes in the NF-κB pathway. NF-κB family members p100 and RelB translocate to the nucleus in response to CO 2 A cohort of RelB protein-protein interactions ( e.g. with Raf-1 and IκBα) are altered by CO 2 exposure, although others are maintained ( e.g. with p100). RelB is processed by CO 2 in a manner dependent on a key C-terminal domain located in its transactivation domain. Loss of the RelB transactivation domain alters NF-κB-dependent transcriptional activity, and loss of p100 alters sensitivity of RelB to CO 2 Thus, we provide molecular insight into the CO 2 sensitivity of the NF-κB pathway and implicate altered RelB/p100-dependent signaling in the CO 2 -dependent regulation of inflammatory signaling. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. PRMT5 regulates IRES-dependent translation via methylation of hnRNP A1

    Science.gov (United States)

    Gao, Guozhen; Dhar, Surbhi

    2017-01-01

    Abstract The type II arginine methyltransferase PRMT5 is responsible for the symmetric dimethylation of histone to generate the H3R8me2s and H4R3me2s marks, which correlate with the repression of transcription. However, the protein level of a number of genes (MEP50, CCND1, MYC, HIF1a, MTIF and CDKN1B) are reported to be downregulated by the loss of PRMT5, while their mRNA levels remain unchanged, which is counterintuitive for PRMT5's proposed role as a transcription repressor. We noticed that the majority of the genes regulated by PRMT5, at the posttranscriptional level, express mRNA containing an internal ribosome entry site (IRES). Using an IRES-dependent reporter system, we established that PRMT5 facilitates the translation of a subset of IRES-containing genes. The heterogeneous nuclear ribonucleoprotein, hnRNP A1, is an IRES transacting factor (ITAF) that regulates the IRES-dependent translation of Cyclin D1 and c-Myc. We showed that hnRNP A1 is methylated by PRMT5 on two residues, R218 and R225, and that this methylation facilitates the interaction of hnRNP A1 with IRES RNA to promote IRES-dependent translation. This study defines a new role for PRMT5 regulation of cellular protein levels, which goes beyond the known functions of PRMT5 as a transcription and splicing regulator. PMID:28115626

  20. A CRE1- regulated cluster is responsible for light dependent production of dihydrotrichotetronin in Trichoderma reesei.

    Directory of Open Access Journals (Sweden)

    Alberto Alonso Monroy

    Full Text Available Changing light conditions, caused by the rotation of earth resulting in day and night or growth on the surface or within a substrate, result in considerably altered physiological processes in fungi. For the biotechnological workhorse Trichoderma reesei, regulation of glycoside hydrolase gene expression, especially cellulase expression was shown to be a target of light dependent gene regulation. Analysis of regulatory targets of the carbon catabolite repressor CRE1 under cellulase inducing conditions revealed a secondary metabolite cluster to be differentially regulated in light and darkness and by photoreceptors. We found that this cluster is involved in production of trichodimerol and that the two polyketide synthases of the cluster are essential for biosynthesis of dihydrotrichotetronine (syn. bislongiquinolide or bisorbibutenolide. Additionally, an indirect influence on production of the peptaibol antibiotic paracelsin was observed. The two polyketide synthetase genes as well as the monooxygenase gene of the cluster were found to be connected at the level of transcription in a positive feedback cycle in darkness, but negative feedback in light, indicating a cellular sensing and response mechanism for the products of these enzymes. The transcription factor TR_102497/YPR2 residing within the cluster regulates the cluster genes in a light dependent manner. Additionally, an interrelationship of this cluster with regulation of cellulase gene expression was detected. Hence the regulatory connection between primary and secondary metabolism appears more widespread than previously assumed, indicating a sophisticated distribution of resources either to degradation of substrate (feed or to antagonism of competitors (fight, which is influenced by light.

  1. Transport, metabolism, and endosomal trafficking-dependent regulation of intestinal fructose absorption

    Science.gov (United States)

    Patel, Chirag; Douard, Veronique; Yu, Shiyan; Gao, Nan; Ferraris, Ronaldo P.

    2015-01-01

    Dietary fructose that is linked to metabolic abnormalities can up-regulate its own absorption, but the underlying regulatory mechanisms are not known. We hypothesized that glucose transporter (GLUT) protein, member 5 (GLUT5) is the primary fructose transporter and that fructose absorption via GLUT5, metabolism via ketohexokinase (KHK), as well as GLUT5 trafficking to the apical membrane via the Ras-related protein-in-brain 11 (Rab11)a-dependent endosomes are each required for regulation. Introducing fructose but not lysine and glucose solutions into the lumen increased by 2- to 10-fold the heterogeneous nuclear RNA, mRNA, protein, and activity levels of GLUT5 in adult wild-type mice consuming chow. Levels of GLUT5 were >100-fold that of candidate apical fructose transporters GLUTs 7, 8, and 12 whose expression, and that of GLUT 2 and the sodium-dependent glucose transporter protein 1 (SGLT1), was not regulated by luminal fructose. GLUT5-knockout (KO) mice exhibited no facilitative fructose transport and no compensatory increases in activity and expression of SGLT1 and other GLUTs. Fructose could not up-regulate GLUT5 in GLUT5-KO, KHK-KO, and intestinal epithelial cell-specific Rab11a-KO mice. The fructose-specific metabolite glyceraldehyde did not increase GLUT5 expression. GLUT5 is the primary transporter responsible for facilitative absorption of fructose, and its regulation specifically requires fructose uptake and metabolism and normal GLUT5 trafficking to the apical membrane.—Patel, C., Douard, V., Yu, S., Gao, N., Ferraris, R. P. Transport, metabolism, and endosomal trafficking-dependent regulation of intestinal fructose absorption. PMID:26071406

  2. Output regulation control for switched stochastic delay systems with dissipative property under error-dependent switching

    Science.gov (United States)

    Li, L. L.; Jin, C. L.; Ge, X.

    2018-01-01

    In this paper, the output regulation problem with dissipative property for a class of switched stochastic delay systems is investigated, based on an error-dependent switching law. Under the assumption that none subsystem is solvable for the problem, a sufficient condition is derived by structuring multiple Lyapunov-Krasovskii functionals with respect to multiple supply rates, via designing error feedback regulators. The condition is also established when dissipative property reduces to passive property. Finally, two numerical examples are given to demonstrate the feasibility and efficiency of the present method.

  3. NLRC5: a key regulator of MHC class I-dependent immune responses.

    Science.gov (United States)

    Kobayashi, Koichi S; van den Elsen, Peter J

    2012-12-01

    The expression of MHC class I molecules is crucial for the initiation and regulation of adaptive immune responses against pathogens. NOD-, LRR- and CARD-containing 5 (NLRC5) was recently identified as a specific transactivator of MHC class I genes (CITA). NLRC5 and the master regulator for MHC class II genes, class II transactivator (CIITA), interact with similar MHC promoter-bound factors. Here, we provide a broad overview of the molecular mechanisms behind MHC class I transcription and the role of the class I transactivator NLRC5 in MHC class I-dependent immune responses.

  4. A single nucleotide change affects fur-dependent regulation of sodB in H. pylori.

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    Beth M Carpenter

    Full Text Available Helicobacter pylori is a significant human pathogen that has adapted to survive the many stresses found within the gastric environment. Superoxide Dismutase (SodB is an important factor that helps H. pylori combat oxidative stress. sodB was previously shown to be repressed by the Ferric Uptake Regulator (Fur in the absence of iron (apo-Fur regulation [1]. Herein, we show that apo regulation is not fully conserved among all strains of H. pylori. apo-Fur dependent changes in sodB expression are not observed under iron deplete conditions in H. pylori strains G27, HPAG1, or J99. However, Fur regulation of pfr and amiE occurs as expected. Comparative analysis of the Fur coding sequence between G27 and 26695 revealed a single amino acid difference, which was not responsible for the altered sodB regulation. Comparison of the sodB promoters from G27 and 26695 also revealed a single nucleotide difference within the predicted Fur binding site. Alteration of this nucleotide in G27 to that of 26695 restored apo-Fur dependent sodB regulation, indicating that a single base difference is at least partially responsible for the difference in sodB regulation observed among these H. pylori strains. Fur binding studies revealed that alteration of this single nucleotide in G27 increased the affinity of Fur for the sodB promoter. Additionally, the single base change in G27 enabled the sodB promoter to bind to apo-Fur with affinities similar to the 26695 sodB promoter. Taken together these data indicate that this nucleotide residue is important for direct apo-Fur binding to the sodB promoter.

  5. State-Dependent Differences in Emotion Regulation Between Unmedicated Bipolar Disorder and Major Depressive Disorder.

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    Rive, Maria M; Mocking, Roel J T; Koeter, Maarten W J; van Wingen, Guido; de Wit, Stella J; van den Heuvel, Odile A; Veltman, Dick J; Ruhé, Henricus G; Schene, Aart H

    2015-07-01

    Major depressive disorder (MDD) and bipolar disorder (BD) are difficult to distinguish clinically during the depressed or remitted states. Both mood disorders are characterized by emotion regulation disturbances; however, little is known about emotion regulation differences between MDD and BD. Better insight into these differences would be helpful for differentiation based on disorder-specific underlying pathophysiological mechanisms. Previous studies comparing these disorders often allowed medication use, limiting generalizability and validity. Moreover, patients with MDD and BD were mostly compared during the depressed, but not the remitted, state, while state might potentially modulate differences between MDD and BD. To investigate positive and negative emotion regulation in medication-free patients with MDD and BD in 2 mood states: depressed or remitted. A cross-sectional study conducted from May 2009 to August 2013 comparing behavioral and functional magnetic resonance imaging emotion regulation data of 42 patients with MDD, 35 with BD, and 36 healthy control (HC) participants free of psychotropic medication recruited from several psychiatric institutions across the Netherlands. A voluntary emotion regulation functional magnetic resonance imaging task using positive and negative pictures. Behavioral and functional magnetic resonance imaging blood oxygen level-dependent responses during emotion regulation. In the remitted state, only patients with BD showed impaired emotion regulation (t = 3.39; P emotion type and associated with increased dorsolateral prefrontal cortex activity compared with those with MDD and healthy control participants (P = .008). In the depressed state, patients with MDD and BD differed with regard to happy vs sad emotion regulation (t = 4.19; P differences in rostral anterior cingulate activity (P emotions poorly compared with those with BD and healthy control participants, while they demonstrated no rostral anterior

  6. BMAL1-dependent regulation of the mTOR signaling pathway delays aging.

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    Khapre, Rohini V; Kondratova, Anna A; Patel, Sonal; Dubrovsky, Yuliya; Wrobel, Michelle; Antoch, Marina P; Kondratov, Roman V

    2014-01-01

    The circadian clock, an internal time-keeping system, has been linked with control of aging, but molecular mechanisms of regulation are not known. BMAL1 is a transcriptional factor and core component of the circadian clock; BMAL1 deficiency is associated with premature aging and reduced lifespan. Here we report that activity of mammalian Target of Rapamycin Complex 1 (mTORC1) is increased upon BMAL1 deficiency both in vivo and in cell culture. Increased mTOR signaling is associated with accelerated aging; in accordance with that, treatment with the mTORC1 inhibitor rapamycin increased lifespan of Bmal1-/- mice by 50%. Our data suggest that BMAL1 is a negative regulator of mTORC1 signaling. We propose that the circadian clock controls the activity of the mTOR pathway through BMAL1-dependent mechanisms and this regulation is important for control of aging and metabolism.

  7. HIV-1 matrix dependent membrane targeting is regulated by Gag mRNA trafficking.

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    Jing Jin

    Full Text Available Retroviral Gag polyproteins are necessary and sufficient for virus budding. Productive HIV-1 Gag assembly takes place at the plasma membrane. However, little is known about the mechanisms by which thousands of Gag molecules are targeted to the plasma membrane. Using a bimolecular fluorescence complementation (BiFC assay, we recently reported that the cellular sites and efficiency of HIV-1 Gag assembly depend on the precise pathway of Gag mRNA export from the nucleus, known to be mediated by Rev. Here we describe an assembly deficiency in human cells for HIV Gag whose expression depends on hepatitis B virus (HBV post-transcriptional regulatory element (PRE mediated-mRNA nuclear export. PRE-dependent HIV Gag expressed well in human cells, but assembled with slower kinetics, accumulated intracellularly, and failed to associate with a lipid raft compartment where the wild-type Rev-dependent HIV-1 Gag efficiently assembles. Surprisingly, assembly and budding of PRE-dependent HIV Gag in human cells could be rescued in trans by co-expression of Rev-dependent Gag that provides correct membrane targeting signals, or in cis by replacing HIV matrix (MA with other membrane targeting domains. Taken together, our results demonstrate deficient membrane targeting of PRE-dependent HIV-1 Gag and suggest that HIV MA function is regulated by the trafficking pathway of the encoding mRNA.

  8. Age-dependent regulation of ERF-VII transcription factor activity in Arabidopsis thaliana.

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    Giuntoli, Beatrice; Shukla, Vinay; Maggiorelli, Federica; Giorgi, Federico M; Lombardi, Lara; Perata, Pierdomenico; Licausi, Francesco

    2017-10-01

    The Group VII Ethylene Responsive Factors (ERFs-VII) RAP2.2 and RAP2.12 have been mainly characterized with regard to their contribution as activators of fermentation in plants. However, transcriptional changes measured in conditions that stabilize these transcription factors exceed the mere activation of this biochemical pathway, implying additional roles performed by the ERF-VIIs in other processes. We evaluated gene expression in transgenic Arabidopsis lines expressing a stabilized form of RAP2.12, or hampered in ERF-VII activity, and identified genes affected by this transcriptional regulator and its homologs, including some involved in oxidative stress response, which are not universally induced under anaerobic conditions. The contribution of the ERF-VIIs in regulating this set of genes in response to chemically induced or submergence-stimulated mitochondria malfunctioning was found to depend on the plant developmental stage. A similar age-dependent mechanism also restrained ERF-VII activity upon the core-hypoxic genes, independently of the N-end rule pathway, which is accounted for the control of the anaerobic response. To conclude, this study shed new light on a dual role of ERF-VII proteins under submergence: as positive regulators of the hypoxic response and as repressors of oxidative-stress related genes, depending on the developmental stage at which plants are challenged by stress conditions. © 2017 John Wiley & Sons Ltd.

  9. Focal adhesion kinase regulates neuronal growth, synaptic plasticity and hippocampus-dependent spatial learning and memory.

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    Monje, Francisco J; Kim, Eun-Jung; Pollak, Daniela D; Cabatic, Maureen; Li, Lin; Baston, Arthur; Lubec, Gert

    2012-01-01

    The focal adhesion kinase (FAK) is a non-receptor tyrosine kinase abundantly expressed in the mammalian brain and highly enriched in neuronal growth cones. Inhibitory and facilitatory activities of FAK on neuronal growth have been reported and its role in neuritic outgrowth remains controversial. Unlike other tyrosine kinases, such as the neurotrophin receptors regulating neuronal growth and plasticity, the relevance of FAK for learning and memory in vivo has not been clearly defined yet. A comprehensive study aimed at determining the role of FAK in neuronal growth, neurotransmitter release and synaptic plasticity in hippocampal neurons and in hippocampus-dependent learning and memory was therefore undertaken using the mouse model. Gain- and loss-of-function experiments indicated that FAK is a critical regulator of hippocampal cell morphology. FAK mediated neurotrophin-induced neuritic outgrowth and FAK inhibition affected both miniature excitatory postsynaptic potentials and activity-dependent hippocampal long-term potentiation prompting us to explore the possible role of FAK in spatial learning and memory in vivo. Our data indicate that FAK has a growth-promoting effect, is importantly involved in the regulation of the synaptic function and mediates in vivo hippocampus-dependent spatial learning and memory. Copyright © 2011 S. Karger AG, Basel.

  10. Diagnostic Performance of Soluble Triggering Receptor Expressed on Myeloid Cells-1 in Ventilator-Associated Pneumonia of Patients with Ischemic Stroke

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    Yuetian Yu

    2017-01-01

    Full Text Available Objective. To investigate the effect of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1 in serum, bronchoalveolar lavage fluid (BALF, endotracheal aspiration (ETA, and exhaled breath condensate (EBC samples as early biomarkers for the diagnosis of ventilator-associated pneumonia (VAP in patients with ischemic stroke. Methods. One hundred and thirty-two patients with clinically suspected VAP were enrolled in this study. Bronchoscopy was performed on the day of clinically suspected VAP. sTREM-1 levels in serum, BALF, ETA, and EBC were measured. VAP was diagnosed by quantitative cultures of BALF (≥104 cfu/mL. Results. VAP was confirmed in 76 (57.58% cases. Patients with VAP showed significantly higher sTREM-1 in BALF [32.35 (IQR, 30.08–41.72 versus 18.92 (11.89–31.72] pg/mL and in EBC [1.57 (IQR, 1.02–2.61 versus 0.41 (0.19–1.61] pg/mL than patients without VAP. The area under the curve was 0.813 (p<0.001. The optimum cut-off value for sTREM-1 in BALF was 23.61 pg/mL, yielding sensitivity and specificity of 85.5% and 73.1%. sTREM-1 in BALF had excellent correlation with that in EBC (R2 = 0.78, p<0.05. Conclusions. sTREM-1 in EBC and BALF had good diagnostic performance in differentiating patients with and without VAP.

  11. Global regulator SATB1 recruits beta-catenin and regulates T(H2 differentiation in Wnt-dependent manner.

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    Dimple Notani

    2010-01-01

    Full Text Available In vertebrates, the conserved Wnt signalling cascade promotes the stabilization and nuclear accumulation of beta-catenin, which then associates with the lymphoid enhancer factor/T cell factor proteins (LEF/TCFs to activate target genes. Wnt/beta -catenin signalling is essential for T cell development and differentiation. Here we show that special AT-rich binding protein 1 (SATB1, the T lineage-enriched chromatin organizer and global regulator, interacts with beta-catenin and recruits it to SATB1's genomic binding sites. Gene expression profiling revealed that the genes repressed by SATB1 are upregulated upon Wnt signalling. Competition between SATB1 and TCF affects the transcription of TCF-regulated genes upon beta-catenin signalling. GATA-3 is a T helper type 2 (T(H2 specific transcription factor that regulates production of T(H2 cytokines and functions as T(H2 lineage determinant. SATB1 positively regulated GATA-3 and siRNA-mediated knockdown of SATB1 downregulated GATA-3 expression in differentiating human CD4(+ T cells, suggesting that SATB1 influences T(H2 lineage commitment by reprogramming gene expression. In the presence of Dickkopf 1 (Dkk1, an inhibitor of Wnt signalling, GATA-3 is downregulated and the expression of signature T(H2 cytokines such as IL-4, IL-10, and IL-13 is reduced, indicating that Wnt signalling is essential for T(H2 differentiation. Knockdown of beta-catenin also produced similar results, confirming the role of Wnt/beta-catenin signalling in T(H2 differentiation. Furthermore, chromatin immunoprecipitation analysis revealed that SATB1 recruits beta-catenin and p300 acetyltransferase on GATA-3 promoter in differentiating T(H2 cells in a Wnt-dependent manner. SATB1 coordinates T(H2 lineage commitment by reprogramming gene expression. The SATB1:beta-catenin complex activates a number of SATB1 regulated genes, and hence this study has potential to find novel Wnt responsive genes. These results demonstrate that SATB1

  12. The DNA replication checkpoint directly regulates MBF-dependent G1/S transcription.

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    Dutta, Chaitali; Patel, Prasanta K; Rosebrock, Adam; Oliva, Anna; Leatherwood, Janet; Rhind, Nicholas

    2008-10-01

    The DNA replication checkpoint transcriptionally upregulates genes that allow cells to adapt to and survive replication stress. Our results show that, in the fission yeast Schizosaccharomyces pombe, the replication checkpoint regulates the entire G(1)/S transcriptional program by directly regulating MBF, the G(1)/S transcription factor. Instead of initiating a checkpoint-specific transcriptional program, the replication checkpoint targets MBF to maintain the normal G(1)/S transcriptional program during replication stress. We propose a mechanism for this regulation, based on in vitro phosphorylation of the Cdc10 subunit of MBF by the Cds1 replication-checkpoint kinase. Replacement of two potential phosphorylation sites with phosphomimetic amino acids suffices to promote the checkpoint transcriptional program, suggesting that Cds1 phosphorylation directly regulates MBF-dependent transcription. The conservation of MBF between fission and budding yeast, and recent results implicating MBF as a target of the budding yeast replication checkpoint, suggests that checkpoint regulation of the MBF transcription factor is a conserved strategy for coping with replication stress. Furthermore, the structural and regulatory similarity between MBF and E2F, the metazoan G(1)/S transcription factor, suggests that this checkpoint mechanism may be broadly conserved among eukaryotes.

  13. The DNA Replication Checkpoint Directly Regulates MBF-Dependent G1/S Transcription▿

    Science.gov (United States)

    Dutta, Chaitali; Patel, Prasanta K.; Rosebrock, Adam; Oliva, Anna; Leatherwood, Janet; Rhind, Nicholas

    2008-01-01

    The DNA replication checkpoint transcriptionally upregulates genes that allow cells to adapt to and survive replication stress. Our results show that, in the fission yeast Schizosaccharomyces pombe, the replication checkpoint regulates the entire G1/S transcriptional program by directly regulating MBF, the G1/S transcription factor. Instead of initiating a checkpoint-specific transcriptional program, the replication checkpoint targets MBF to maintain the normal G1/S transcriptional program during replication stress. We propose a mechanism for this regulation, based on in vitro phosphorylation of the Cdc10 subunit of MBF by the Cds1 replication-checkpoint kinase. Replacement of two potential phosphorylation sites with phosphomimetic amino acids suffices to promote the checkpoint transcriptional program, suggesting that Cds1 phosphorylation directly regulates MBF-dependent transcription. The conservation of MBF between fission and budding yeast, and recent results implicating MBF as a target of the budding yeast replication checkpoint, suggests that checkpoint regulation of the MBF transcription factor is a conserved strategy for coping with replication stress. Furthermore, the structural and regulatory similarity between MBF and E2F, the metazoan G1/S transcription factor, suggests that this checkpoint mechanism may be broadly conserved among eukaryotes. PMID:18662996

  14. Regulator of calcineurin 1 differentially regulates TLR-dependent MyD88 and TRIF signaling pathways.

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    Zheng Pang

    Full Text Available Toll-like receptors (TLRs recognize the conserved molecular patterns in microorganisms and trigger myeloid differentiation primary response 88 (MyD88 and/or TIR-domain-containing adapter-inducing interferon-β (TRIF pathways that are critical for host defense against microbial infection. However, the molecular mechanisms that govern TLR signaling remain incompletely understood. Regulator of calcineurin-1 (RCAN1, a small evolutionarily conserved protein that inhibits calcineurin phosphatase activity, suppresses inflammation during Pseudomonas aeruginosa infection. Here, we define the roles for RCAN1 in P. aeruginosa lipopolysaccharide (LPS-activated TLR4 signaling. We compared the effects of P. aeruginosa LPS challenge on bone marrow-derived macrophages from both wild-type and RCAN1-deficient mice and found that RCAN1 deficiency increased the MyD88-NF-κB-mediated cytokine production (IL-6, TNF and MIP-2, whereas TRIF-interferon-stimulated response elements (ISRE-mediated cytokine production (IFNβ, RANTES and IP-10 was suppressed. RCAN1 deficiency caused increased IκBα phosphorylation and NF-κB activity in the MyD88-dependent pathway, but impaired ISRE activation and reduced IRF7 expression in the TRIF-dependent pathway. Complementary studies of a mouse model of P. aeruginosa LPS-induced acute pneumonia confirmed that RCAN1-deficient mice displayed greatly enhanced NF-κB activity and MyD88-NF-κB-mediated cytokine production, which correlated with enhanced pulmonary infiltration of neutrophils. By contrast, RCAN1 deficiency had little effect on the TRIF pathway in vivo. These findings demonstrate a novel regulatory role of RCAN1 in TLR signaling, which differentially regulates MyD88 and TRIF pathways.

  15. Light Signaling-Dependent Regulation of Photoinhibition and Photoprotection in Tomato.

    Science.gov (United States)

    Wang, Feng; Wu, Nan; Zhang, Luyue; Ahammed, Golam Jalal; Chen, Xiaoxiao; Xiang, Xun; Zhou, Jie; Xia, Xiaojian; Shi, Kai; Yu, Jingquan; Foyer, Christine H; Zhou, Yanhong

    2018-02-01

    Photoreceptor-mediated light signaling plays a critical role in plant growth, development, and stress responses but its contribution to the spatial regulation of photoinhibition and photoprotection within the canopy remains unclear. Here, we show that low-red/far-red ( L - R / FR ) ratio light conditions significantly alleviate PSII and PSI photoinhibition in the shade leaves of tomato ( Solanum lycopersicum ) plants. This protection is accompanied by a phytochrome A-dependent induction of LONG HYPOCOTYL5 (HY5). HY5 binds to the promoter of ABA INSENSITIVE 5 ( ABI5 ), triggering RESPIRATORY BURST OXIDASE HOMOLOG1 ( RBOH1 )-dependent H 2 O 2 production in the apoplast. Decreased levels of HY5 , ABI5 , and RBOH1 transcripts increased cold-induced photoinhibition and abolished L - R / FR -induced alleviation of photoinhibition. L - R / FR illumination induced nonphotochemical quenching (NPQ) of chlorophyll a fluorescence and increased the activities of Foyer-Halliwell-Asada cycle enzymes and cyclic electron flux (CEF) around PSI. In contrast, decreased HY5 , ABI5 , and RBOH1 transcript levels abolished the positive effect of L - R / FR on photoprotection. Loss of PROTON GRADIENT REGULATION5 -dependent CEF led to increased photoinhibition and attenuated L - R / FR -dependent NPQ. These data demonstrate that HY5 is an important hub in the cross talk between light and cold response pathways, integrating ABA and reactive oxygen species signaling, leading to the attenuation of photoinhibition by enhanced induction of photoprotection in shade leaves. © 2018 American Society of Plant Biologists. All Rights Reserved.

  16. Estrogen receptor alpha is cell cycle-regulated and regulates the cell cycle in a ligand-dependent fashion.

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    JavanMoghadam, Sonia; Weihua, Zhang; Hunt, Kelly K; Keyomarsi, Khandan

    2016-06-17

    Estrogen receptor alpha (ERα) has been implicated in several cell cycle regulatory events and is an important predictive marker of disease outcome in breast cancer patients. Here, we aimed to elucidate the mechanism through which ERα influences proliferation in breast cancer cells. Our results show that ERα protein is cell cycle-regulated in human breast cancer cells and that the presence of 17-β-estradiol (E2) in the culture medium shortened the cell cycle significantly (by 4.5 hours, P cycle duration were observed in the S and G2/M phases, whereas the G1 phase was indistinguishable under liganded and unliganded conditions. In addition, ERα knockdown in MCF-7 cells accelerated mitotic exit, whereas transfection of ERα-negative MDA-MB-231 cells with exogenous ERα significantly shortened the S and G2/M phases (by 9.1 hours, P cycle progression through the S and G2/M phases than fulvestrant does, presumably because of the destabilizing effect of fulvestrant on ERα protein. Together, these results show that ERα modulates breast cancer cell proliferation by regulating events during the S and G2/M phases of the cell cycle in a ligand-dependent fashion. These results provide the rationale for an effective treatment strategy that includes a cell cycle inhibitor in combination with a drug that lowers estrogen levels, such as an aromatase inhibitor, and an antiestrogen that does not result in the degradation of ERα, such as tamoxifen.

  17. UDP/P2Y6 receptor signaling regulates IgE-dependent degranulation in human basophils

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    Manabu Nakano

    2017-10-01

    Conclusions: This study showed that UDP/P2Y6 receptor signaling is involved in the regulation of IgE-dependent degranulation in basophils, which might stimulate the P2Y6 receptor via the autocrine secretion of UTP. Thus, this receptor represents a potential target to regulate IgE-dependent degranulation in basophils during allergic diseases.

  18. Ablation of the Leptin receptor in Myeloid Cells Impairs Pulmonary Clearance of Streptococcus Pneumoniae and Alveolar Macrophage Bactericidal Function.

    Science.gov (United States)

    Mancuso, Peter; Curtis, Jeffrey L; Freeman, Christine M; Peters-Golden, Marc; Weinberg, Jason B; Myers, Martin G

    2018-03-22

    Leptin is a pleiotropic hormone produced by white adipose tissue that regulates appetite and many physiologic functions including the immune response to infection. Genetic leptin deficiency in humans and mice impairs host defenses against respiratory tract infections. Since leptin deficiency is associated with obesity and other metabolic abnormalities, we generated mice that lack the leptin receptor (LepRb) in cells of the myeloid linage (LysM-LepRb-KO) to evaluate its impact in lean metabolically normal mice in a murine model of pneumococcal pneumonia. We observed higher lung and spleen bacterial burdens in LysM-LepRb-KO mice following an intratracheal challenge with S. pneumoniae. Although numbers of leukocytes recovered from bronchoalveolar lavage fluid did not differ between groups, we did observe higher levels of pulmonary IL-13 and TNFα in LysM-LepRb-KO mice 48 h post-infection. Phagocytosis and killing of ingested S. pneumoniae were also impaired in alveolar macrophages (AM)s from LysM-LepRb-KO mice in vitro, and was associated with reduced LTB4 and enhanced PGE2 synthesis in vitro. Pretreatment of AMs with LTB4 and the cyclooxygenase inhibitor, indomethacin, restored phagocytosis but not bacterial killing in vitro. These results, confirm our previous observations in leptin-deficient (ob/ob) and fasted mice, and demonstrate that decreased leptin action, as opposed to metabolic irregularities associated with obesity or starvation, are responsible for the defective host defense against pneumococcal pneumonia. They also provide novel targets for therapeutic intervention in humans with bacterial pneumonia.

  19. Regulation of RNA-dependent RNA polymerase 1 and isochorismate synthase gene expression in Arabidopsis.

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    Lydia J R Hunter

    Full Text Available RNA-dependent RNA polymerases (RDRs function in anti-viral silencing in Arabidopsis thaliana and other plants. Salicylic acid (SA, an important defensive signal, increases RDR1 gene expression, suggesting that RDR1 contributes to SA-induced virus resistance. In Nicotiana attenuata RDR1 also regulates plant-insect interactions and is induced by another important signal, jasmonic acid (JA. Despite its importance in defense RDR1 regulation has not been investigated in detail.In Arabidopsis, SA-induced RDR1 expression was dependent on 'NON-EXPRESSER OF PATHOGENESIS-RELATED GENES 1', indicating regulation involves the same mechanism controlling many other SA- defense-related genes, including pathogenesis-related 1 (PR1. Isochorismate synthase 1 (ICS1 is required for SA biosynthesis. In defensive signal transduction RDR1 lies downstream of ICS1. However, supplying exogenous SA to ics1-mutant plants did not induce RDR1 or PR1 expression to the same extent as seen in wild type plants. Analysing ICS1 gene expression using transgenic plants expressing ICS1 promoter:reporter gene (β-glucuronidase constructs and by measuring steady-state ICS1 transcript levels showed that SA positively regulates ICS1. In contrast, ICS2, which is expressed at lower levels than ICS1, is unaffected by SA. The wound-response hormone JA affects expression of Arabidopsis RDR1 but jasmonate-induced expression is independent of CORONATINE-INSENSITIVE 1, which conditions expression of many other JA-responsive genes. Transiently increased RDR1 expression following tobacco mosaic virus inoculation was due to wounding and was not a direct effect of infection. RDR1 gene expression was induced by ethylene and by abscisic acid (an important regulator of drought resistance. However, rdr1-mutant plants showed normal responses to drought.RDR1 is regulated by a much broader range of phytohormones than previously thought, indicating that it plays roles beyond those already suggested in virus

  20. SMU.940 regulates dextran-dependent aggregation and biofilm formation in Streptococcus mutans.

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    Senpuku, Hidenobu; Yonezawa, Hideo; Yoneda, Saori; Suzuki, Itaru; Nagasawa, Ryo; Narisawa, Naoki

    2018-02-01

    The oral bacterium Streptococcus mutans is the principal agent in the development of dental caries. Biofilm formation by S. mutans requires bacterial attachment, aggregation, and glucan formation on the tooth surface under sucrose supplementation conditions. Our previous microarray analysis of clinical strains identified 74 genes in S. mutans that were related to biofilm morphology; however, the roles of almost all of these genes in biofilm formation are poorly understood. We investigated the effects of 21 genes randomly selected from our previous study regarding S. mutans biofilm formation, regulation by the complement pathway, and responses to competence-stimulating peptide. Eight competence-stimulating peptide-dependent genes were identified, and their roles in biofilm formation and aggregation were examined by mutational analyses of the S. mutansUA159 strain. Of these eight genes, the inactivation of the putative hemolysin III family SMU.940 gene of S. mutansUA159 promoted rapid dextran-dependent aggregation and biofilm formation in tryptic soy broth without dextrose (TSB) with 0.25% glucose and slightly reduced biofilm formation in TSB with 0.25% sucrose. The SMU.940 mutant showed higher expression of GbpC and gbpC gene than wild-type. GbpC is known to be involved in the dextran-dependent aggregation of S. mutans. An SMU.940-gbpC double mutant strain was constructed in the SMU.940 mutant background. The gbpC mutation completely abolished the dextran-dependent aggregation of the SMU.940 mutant. In addition, the aggregation of the mutant was abrogated by dextranase. These findings suggest that SMU.940 controls GbpC expression, and contributes to the regulation of dextran-dependent aggregation and biofilm formation. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Thiamin diphosphate-dependent enzymes: from enzymology to metabolic regulation, drug design and disease models.

    Science.gov (United States)

    Bunik, Victoria I; Tylicki, Adam; Lukashev, Nikolay V

    2013-12-01

    Bringing a knowledge of enzymology into research in vivo and in situ is of great importance in understanding systems biology and metabolic regulation. The central metabolic significance of thiamin (vitamin B1 ) and its diphosphorylated derivative (thiamin diphosphate; ThDP), and the fundamental differences in the ThDP-dependent enzymes of metabolic networks in mammals versus plants, fungi and bacteria, or in health versus disease, suggest that these enzymes are promising targets for biotechnological and medical applications. Here, the in vivo action of known regulators of ThDP-dependent enzymes, such as synthetic structural analogs of the enzyme substrates and thiamin, is analyzed in light of the enzymological data accumulated during half a century of research. Mimicking the enzyme-specific catalytic intermediates, the phosphonate analogs of 2-oxo acids selectively inhibit particular ThDP-dependent enzymes. Because of their selectivity, use of these compounds in cellular and animal models of ThDP-dependent enzyme malfunctions improves the validity of the model and its predictive power when compared with the nonselective and enzymatically less characterized oxythiamin and pyrithiamin. In vitro studies of the interaction of thiamin analogs and their biological derivatives with potential in vivo targets are necessary to identify and attenuate the analog selectivity. For both the substrate and thiamin synthetic analogs, in vitro reactivities with potential targets are highly relevant in vivo. However, effective concentrations in vivo are often higher than in vitro studies would suggest. The significance of specific inihibition of the ThDP-dependent enzymes for the development of herbicides, antibiotics, anticancer and neuroprotective strategies is discussed. © 2013 FEBS.

  2. Cell cycle-dependent Rho GTPase activity dynamically regulates cancer cell motility and invasion in vivo.

    Science.gov (United States)

    Kagawa, Yoshinori; Matsumoto, Shinji; Kamioka, Yuji; Mimori, Koshi; Naito, Yoko; Ishii, Taeko; Okuzaki, Daisuke; Nishida, Naohiro; Maeda, Sakae; Naito, Atsushi; Kikuta, Junichi; Nishikawa, Keizo; Nishimura, Junichi; Haraguchi, Naotsugu; Takemasa, Ichiro; Mizushima, Tsunekazu; Ikeda, Masataka; Yamamoto, Hirofumi; Sekimoto, Mitsugu; Ishii, Hideshi; Doki, Yuichiro; Matsuda, Michiyuki; Kikuchi, Akira; Mori, Masaki; Ishii, Masaru

    2013-01-01

    The mechanism behind the spatiotemporal control of cancer cell dynamics and its possible association with cell proliferation has not been well established. By exploiting the intravital imaging technique, we found that cancer cell motility and invasive properties were closely associated with the cell cycle. In vivo inoculation of human colon cancer cells bearing fluorescence ubiquitination-based cell cycle indicator (Fucci) demonstrated an unexpected phenomenon: S/G2/M cells were more motile and invasive than G1 cells. Microarray analyses showed that Arhgap11a, an uncharacterized Rho GTPase-activating protein (RhoGAP), was expressed in a cell-cycle-dependent fashion. Expression of ARHGAP11A in cancer cells suppressed RhoA-dependent mechanisms, such as stress fiber formation and focal adhesion, which made the cells more prone to migrate. We also demonstrated that RhoA suppression by ARHGAP11A induced augmentation of relative Rac1 activity, leading to an increase in the invasive properties. RNAi-based inhibition of Arhgap11a reduced the invasion and in vivo expansion of cancers. Additionally, analysis of human specimens showed the significant up-regulation of Arhgap11a in colon cancers, which was correlated with clinical invasion status. The present study suggests that ARHGAP11A, a cell cycle-dependent RhoGAP, is a critical regulator of cancer cell mobility and is thus a promising therapeutic target in invasive cancers.

  3. Cell cycle-dependent Rho GTPase activity dynamically regulates cancer cell motility and invasion in vivo.

    Directory of Open Access Journals (Sweden)

    Yoshinori Kagawa

    Full Text Available The mechanism behind the spatiotemporal control of cancer cell dynamics and its possible association with cell proliferation has not been well established. By exploiting the intravital imaging technique, we found that cancer cell motility and invasive properties were closely associated with the cell cycle. In vivo inoculation of human colon cancer cells bearing fluorescence ubiquitination-based cell cycle indicator (Fucci demonstrated an unexpected phenomenon: S/G2/M cells were more motile and invasive than G1 cells. Microarray analyses showed that Arhgap11a, an uncharacterized Rho GTPase-activating protein (RhoGAP, was expressed in a cell-cycle-dependent fashion. Expression of ARHGAP11A in cancer cells suppressed RhoA-dependent mechanisms, such as stress fiber formation and focal adhesion, which made the cells more prone to migrate. We also demonstrated that RhoA suppression by ARHGAP11A induced augmentation of relative Rac1 activity, leading to an increase in the invasive properties. RNAi-based inhibition of Arhgap11a reduced the invasion and in vivo expansion of cancers. Additionally, analysis of human specimens showed the significant up-regulation of Arhgap11a in colon cancers, which was correlated with clinical invasion status. The present study suggests that ARHGAP11A, a cell cycle-dependent RhoGAP, is a critical regulator of cancer cell mobility and is thus a promising therapeutic target in invasive cancers.

  4. Environment-dependent regulation of spliceosome activity by the LSM2-8 complex in Arabidopsis.

    Science.gov (United States)

    Carrasco-López, Cristian; Hernández-Verdeja, Tamara; Perea-Resa, Carlos; Abia, David; Catalá, Rafael; Salinas, Julio

    2017-07-07

    Spliceosome activity is tightly regulated to ensure adequate splicing in response to internal and external cues. It has been suggested that core components of the spliceosome, such as the snRNPs, would participate in the control of its activity. The experimental indications supporting this proposition, however, remain scarce, and the operating mechanisms poorly understood. Here, we present genetic and molecular evidence demonstrating that the LSM2-8 complex, the protein moiety of the U6 snRNP, regulates the spliceosome activity in Arabidopsis, and that this regulation is controlled by the environmental conditions. Our results show that the complex ensures the efficiency and accuracy of constitutive and alternative splicing of selected pre-mRNAs, depending on the conditions. Moreover, miss-splicing of most targeted pre-mRNAs leads to the generation of nonsense mediated decay signatures, indicating that the LSM2-8 complex also guarantees adequate levels of the corresponding functional transcripts. Interestingly, the selective role of the complex has relevant physiological implications since it is required for adequate plant adaptation to abiotic stresses. These findings unveil an unanticipated function for the LSM2-8 complex that represents a new layer of posttranscriptional regulation in response to external stimuli in eukaryotes. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  5. Modeling of pulsatile flow-dependent nitric oxide regulation in a realistic microvascular network.

    Science.gov (United States)

    Wang, Ruofan; Pan, Qing; Kuebler, Wolfgang M; Li, John K-J; Pries, Axel R; Ning, Gangmin

    2017-09-01

    Hemodynamic pulsatility has been reported to regulate microcirculatory function. To quantitatively assess the impact of flow pulsatility on the microvasculature, a mathematical model was first developed to simulate the regulation of NO production by pulsatile flow in the microcirculation. Shear stress and pressure pulsatility were selected as regulators of endothelial NO production and NO-dependent vessel dilation as feedback to control microvascular hemodynamics. The model was then applied to a real microvascular network of the rat mesentery consisting of 546 microvessels. As compared to steady flow conditions, pulsatile flow increased the average NO concentration in arterioles from 256.8±93.1nM to 274.8±101.1nM (Pflow as compared to steady flow conditions. Network perfusion and flow heterogeneity were improved under pulsatile flow conditions, and vasodilation within the network was more sensitive to heart rate changes than pulse pressure amplitude. The proposed model simulates the role of flow pulsatility in the regulation of a complex microvascular network in terms of NO concentration and hemodynamics under varied physiological conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Functional Role of Cyclin-Dependent Kinase 5 in the Regulation of Melanogenesis and Epidermal Structure.

    Science.gov (United States)

    Dong, Changsheng; Yang, Shanshan; Fan, Ruiwen; Ji, Kaiyuan; Zhang, Junzhen; Liu, Xuexian; Hu, Shuaipeng; Xie, Jianshan; Liu, Yu; Gao, Wenjun; Wang, Haidong; Yao, Jianbo; Smith, George W; Herrid, Muren

    2017-10-23

    The mammalian integumentary system plays important roles in body homeostasis, and dysfunction of melanogenesis or epidermal development may lead to a variety of skin diseases, including melanoma. Skin pigmentation in humans and coat color in fleece-producing animals are regulated by many genes. Among them, microphthalmia-associated transcription factor (MITF) and paired-box 3 (PAX3) are at the top of the cascade and regulate activities of many important melanogenic enzymes. Here, we report for the first time that cyclin-dependent kinase 5 (Cdk5) is an essential regulator of MITF and PAX3. Cdk5 knockdown in mice causes a lightened coat color, a polarized distribution of melanin and hyperproliferation of basal keratinocytes. Reduced expression of Keratin 10 (K10) resulting from Cdk5 knockdown may be responsible for an abnormal epidermal structure. In contrast, overexpression of Cdk5 in sheep (Ovis aries) only produces brown patches on a white background, with no other observable abnormalities. Collectively, our findings show that Cdk5 has an important functional role in the regulation of melanin production and transportation and in normal development of the integumentary system.

  7. Hydroxyoctadecadienoic acids regulate apoptosis in human THP-1 cells in a PPARγ-dependent manner.

    Science.gov (United States)

    Vangaveti, Venkat N; Shashidhar, Venkatesh M; Rush, Catherine; Malabu, Usman H; Rasalam, Roy R; Collier, Fiona; Baune, Bernhard T; Kennedy, Richard L

    2014-12-01

    Macrophage apoptosis, a key process in atherogenesis, is regulated by oxidation products, including hydroxyoctadecadienoic acids (HODEs). These stable oxidation products of linoleic acid (LA) are abundant in atherosclerotic plaque and activate PPARγ and GPR132. We investigated the mechanisms through which HODEs regulate apoptosis. The effect of HODEs on THP-1 monocytes and adherent THP-1 cells were compared with other C18 fatty acids, LA and α-linolenic acid (ALA). The number of cells was reduced within 24 hours following treatment with 9-HODE (p labelling of cells (p blocked by the caspase inhibitor DEVD-CHO. The PPARγ antagonist T0070907 further increased apoptosis, suggestive of the PPARγ-regulated apoptotic effects induced by 9-HODE. The use of siRNA for GPR132 showed no evidence that the effect of HODEs was mediated through this receptor. 9-HODE and 13-HODE are potent--and specific--regulators of apoptosis in THP-1 cells. Their action is PPARγ-dependent and independent of GPR132. Further studies to identify the signalling pathways through which HODEs increase apoptosis in macrophages may reveal novel therapeutic targets for atherosclerosis.

  8. Density-dependent intraspecific aggression regulates survival in northern Yellowstone wolves (Canis lupus).

    Science.gov (United States)

    Cubaynes, Sarah; MacNulty, Daniel R; Stahler, Daniel R; Quimby, Kira A; Smith, Douglas W; Coulson, Tim

    2014-11-01

    Understanding the population dynamics of top-predators is essential to assess their impact on ecosystems and to guide their management. Key to this understanding is identifying the mechanisms regulating vital rates. Determining the influence of density on survival is necessary to understand the extent to which human-caused mortality is compensatory or additive. In wolves (Canis lupus), empirical evidence for density-dependent survival is lacking. Dispersal is considered the principal way in which wolves adjust their numbers to prey supply or compensate for human exploitation. However, studies to date have primarily focused on exploited wolf populations, in which density-dependent mechanisms are likely weak due to artificially low wolf densities. Using 13 years of data on 280 collared wolves in Yellowstone National Park, we assessed the effect of wolf density, prey abundance and population structure, as well as winter severity, on age-specific survival in two areas (prey-rich vs. prey-poor) of the national park. We further analysed cause-specific mortality and explored the factors driving intraspecific aggression in the prey-rich northern area of the park. Overall, survival rates decreased during the study. In northern Yellowstone, density dependence regulated adult survival through an increase in intraspecific aggression, independent of prey availability. In the interior of the park, adult survival was less variable and density-independent, despite reduced prey availability. There was no effect of prey population structure in northern Yellowstone, or of winter severity in either area. Survival was similar among yearlings and adults, but lower for adults older than 6 years. Our results indicate that density-dependent intraspecific aggression is a major driver of adult wolf survival in northern Yellowstone, suggesting intrinsic density-dependent mechanisms have the potential to regulate wolf populations at high ungulate densities. When low prey availability or high

  9. Ca2+-Dependent Regulations and Signaling in Skeletal Muscle: From Electro-Mechanical Coupling to Adaptation

    Science.gov (United States)

    Gehlert, Sebastian; Bloch, Wilhelm; Suhr, Frank

    2015-01-01

    Calcium (Ca2+) plays a pivotal role in almost all cellular processes and ensures the functionality of an organism. In skeletal muscle fibers, Ca2+ is critically involved in the innervation of skeletal muscle fibers that results in the exertion of an action potential along the muscle fiber membrane, the prerequisite for skeletal muscle contraction. Furthermore and among others, Ca2+ regulates also intracellular processes, such as myosin-actin cross bridging, protein synthesis, protein degradation and fiber type shifting by the control of Ca2+-sensitive proteases and transcription factors, as well as mitochondrial adaptations, plasticity and respiration. These data highlight the overwhelming significance of Ca2+ ions for the integrity of skeletal muscle tissue. In this review, we address the major functions of Ca2+ ions in adult muscle but also highlight recent findings of critical Ca2+-dependent mechanisms essential for skeletal muscle-regulation and maintenance. PMID:25569087

  10. Bombyx mori cyclin-dependent kinase inhibitor is involved in regulation of the silkworm cell cycle.

    Science.gov (United States)

    Tang, X-F; Zhou, X-L; Zhang, Q; Chen, P; Lu, C; Pan, M-H

    2018-06-01

    Cyclin-dependent kinase inhibitors (CKIs) are negative regulators of the cell cycle. They can bind to cyclin-dependent kinase (CDK)-cyclin complexes and inhibit CDK activities. We identified a single homologous gene of the CDK interacting protein/kinase inhibitory protein (Cip/Kip) family, BmCKI, in the silkworm, Bombyx mori. The gene transcribes two splice variants: a 654-bp-long BmCKI-L (the longer splice variant) encoding a protein with 217 amino acids and a 579-bp-long BmCKI-S (the shorter splice variant) encoding a protein with 192 amino acids. BmCKI-L and BmCKI-S contain the Cip/Kip family conserved cyclin-binding domain and the CDK-binding domain. They are localized in the nucleus and have an unconventional bipartite nuclear localization signal at amino acid residues 181-210. Overexpression of BmCKI-L or BmCKI-S affected cell cycle progression; the cell cycle was arrested in the first gap phase of cell cycle (G1). RNA interference of BmCKI-L or BmCKI-S led to cells accumulating in the second gap phase and the mitotic phase of cell cycle (G2/M). Both BmCKI-L and BmCKI-S are involved in cell cycle regulation and probably have similar effects. The transgenic silkworm with BmCKI-L overexpression (BmCKI-L-OE), exhibited embryonic lethal, larva developmental retardation and lethal phenotypes. These results suggest that BmCKI-L might regulate the growth and development of silkworm. These findings clarify the function of CKIs and increase our understanding of cell cycle regulation in the silkworm. © 2018 The Royal Entomological Society.

  11. Voltage dependent anion channel-1 regulates death receptor mediated apoptosis by enabling cleavage of caspase-8

    International Nuclear Information System (INIS)

    Chacko, Alex D; Liberante, Fabio; Paul, Ian; Longley, Daniel B; Fennell, Dean A

    2010-01-01

    Activation of the extrinsic apoptosis pathway by tumour necrosis factor related apoptosis inducing ligand (TRAIL) is a novel therapeutic strategy for treating cancer that is currently under clinical evaluation. Identification of molecular biomarkers of resistance is likely to play an important role in predicting clinical anti tumour activity. The involvement of the mitochondrial type 1 voltage dependent anion channel (VDAC1) in regulating apoptosis has been highly debated. To date, a functional role in regulating the extrinsic apoptosis pathway has not been formally excluded. We carried out stable and transient RNAi knockdowns of VDAC1 in non-small cell lung cancer cells, and stimulated the extrinsic apoptotic pathway principally by incubating cells with the death ligand TRAIL. We used in-vitro apoptotic and cell viability assays, as well as western blot for markers of apoptosis, to demonstrate that TRAIL-induced toxicity is VDAC1 dependant. Confocal microscopy and mitochondrial fractionation were used to determine the importance of mitochondria for caspase-8 activation. Here we show that either stable or transient knockdown of VDAC1 is sufficient to antagonize TRAIL mediated apoptosis in non-small cell lung cancer (NSCLC) cells. Specifically, VDAC1 is required for processing of procaspase-8 to its fully active p18 form at the mitochondria. Loss of VDAC1 does not alter mitochondrial sensitivity to exogenous caspase-8-cleaved BID induced mitochondrial depolarization, even though VDAC1 expression is essential for TRAIL dependent activation of the intrinsic apoptosis pathway. Furthermore, expression of exogenous VDAC1 restores the apoptotic response to TRAIL in cells in which endogenous VDAC1 has been selectively silenced. Expression of VDAC1 is required for full processing and activation of caspase-8 and supports a role for mitochondria in regulating apoptosis signaling via the death receptor pathway

  12. Regulation of the ligand-dependent activation of the epidermal growth factor receptor by calmodulin

    DEFF Research Database (Denmark)

    Li, Hongbing; Panina, Svetlana; Kaur, Amandeep

    2012-01-01

    Calmodulin (CaM) is the major component of calcium signaling pathways mediating the action of various effectors. Transient increases in the intracellular calcium level triggered by a variety of stimuli lead to the formation of Ca2+/CaM complexes, which interact with and activate target proteins....... In the present study the role of Ca2+/CaM in the regulation of the ligand-dependent activation of the epidermal growth factor receptor (EGFR) has been examined in living cells. We show that addition of different cell permeable CaM antagonists to cultured cells or loading cells with a Ca2+ chelator inhibited...

  13. TLR4 has a TP53-dependent dual role in regulating breast cancer cell growth

    OpenAIRE

    Haricharan, Svasti; Brown, Powel

    2015-01-01

    This study fundamentally alters our understanding of how TLR4 drives breast cancer. Although TLR4 was previously considered a tumor promoter, we demonstrate a complex, TP53-dependent role for TLR4 in regulating tumor growth. TP53 is a tumor suppressor commonly inactivated across cancer types. In TP53 wild-type cancer cells, TLR4 activation causes secretion of IFN-γ into the microenvironment, resulting in induction of p21 and inhibition of cell growth. Conversely, TLR4 activation in TP53 mutan...

  14. Cell cycle-regulated expression of mammalian CDC6 is dependent on E2F

    DEFF Research Database (Denmark)

    Hateboer, G; Wobst, A; Petersen, B O

    1998-01-01

    The E2F transcription factors are essential regulators of cell growth in multicellular organisms, controlling the expression of a number of genes whose products are involved in DNA replication and cell proliferation. In Saccharomyces cerevisiae, the MBF and SBF transcription complexes have...... of this gene is dependent on E2F. In vivo footprinting data demonstrate that the identified E2F sites are occupied in resting cells and in exponentially growing cells, suggesting that E2F is responsible for downregulating the promoter in early phases of the cell cycle and the subsequent upregulation when cells...

  15. Light-regulated leaf expansion in two Populus species: dependence on developmentally controlled ion transport.

    Science.gov (United States)

    Stiles, Kari A; Van Volkenburgh, Elizabeth

    2002-07-01

    Leaf growth responses to light have been compared in two species of Populus, P. deltoides and P. trichocarpa. These species differ markedly in morphology, anatomy, and dependence on light during leaf expansion. Light stimulates the growth rate and acidification of cell walls in P. trichocarpa but not in P. deltoides, whereas leaves of P. deltoides maintain growth in the dark. Light-induced growth is promoted in P. deltoides when cells are provided 50-100 mM KCl. In both species, light initially depolarizes, then hyperpolarizes mesophyll plasma membranes. However, in the dark, the resting E(m) of mesophyll cells in P. deltoides, but not in P. trichocarpa, is relatively insensitive to decade changes in external [K+]. Results suggest that light-stimulated leaf growth depends on developmentally regulated cellular mechanisms controlling ion fluxes across the plasma membrane. These developmental differences underlie species-level differences in growth and physiological responses to the photoenvironment.

  16. The dependence of neuronal encoding efficiency on Hebbian plasticity and homeostatic regulation of neurotransmitter release

    Science.gov (United States)

    Faghihi, Faramarz; Moustafa, Ahmed A.

    2015-01-01

    Synapses act as information filters by different molecular mechanisms including retrograde messenger that affect neuronal spiking activity. One of the well-known effects of retrograde messenger in presynaptic neurons is a change of the probability of neurotransmitter release. Hebbian learning describe a strengthening of a synapse between a presynaptic input onto a postsynaptic neuron when both pre- and postsynaptic neurons are coactive. In this work, a theory of homeostatic regulation of neurotransmitter release by retrograde messenger and Hebbian plasticity in neuronal encoding is presented. Encoding efficiency was measured for different synaptic conditions. In order to gain high encoding efficiency, the spiking pattern of a neuron should be dependent on the intensity of the input and show low levels of noise. In this work, we represent spiking trains as zeros and ones (corresponding to non-spike or spike in a time bin, respectively) as words with length equal to three. Then the frequency of each word (here eight words) is measured using spiking trains. These frequencies are used to measure neuronal efficiency in different conditions and for different parameter values. Results show that neurons that have synapses acting as band-pass filters show the highest efficiency to encode their input when both Hebbian mechanism and homeostatic regulation of neurotransmitter release exist in synapses. Specifically, the integration of homeostatic regulation of feedback inhibition with Hebbian mechanism and homeostatic regulation of neurotransmitter release in the synapses leads to even higher efficiency when high stimulus intensity is presented to the neurons. However, neurons with synapses acting as high-pass filters show no remarkable increase in encoding efficiency for all simulated synaptic plasticity mechanisms. This study demonstrates the importance of cooperation of Hebbian mechanism with regulation of neurotransmitter release induced by rapid diffused retrograde

  17. TOR-Dependent and -Independent Pathways Regulate Autophagy in Arabidopsis thaliana.

    Science.gov (United States)

    Pu, Yunting; Luo, Xinjuan; Bassham, Diane C

    2017-01-01

    Autophagy is a critical process for recycling of cytoplasmic materials during environmental stress, senescence and cellular remodeling. It is upregulated under a wide range of abiotic stress conditions and is important for stress tolerance. Autophagy is repressed by the protein kinase target of rapamycin (TOR), which is activated in response to nutrients and in turn upregulates cell growth and translation and inhibits autophagy. Down-regulation of TOR in Arabidopsis thaliana leads to constitutive autophagy and to decreased growth, but the relationship to stress conditions is unclear. Here, we assess the extent to which TOR controls autophagy activation by abiotic stress. Overexpression of TOR inhibited autophagy activation by nutrient starvation, salt and osmotic stress, indicating that activation of autophagy under these conditions requires down-regulation of TOR activity. In contrast, TOR overexpression had no effect on autophagy induced by oxidative stress or ER stress, suggesting that activation of autophagy by these conditions is independent of TOR function. The plant hormone auxin has been shown previously to up-regulate TOR activity. To confirm the existence of two pathways for activation of autophagy, dependent on the stress conditions, auxin was added exogenously to activate TOR, and the effect on autophagy under different conditions was assessed. Consistent with the effect of TOR overexpression, the addition of the auxin NAA inhibited autophagy during nutrient deficiency, salt and osmotic stress, but not during oxidative or ER stress. NAA treatment was unable to block autophagy induced by a TOR inhibitor or by a mutation in the TOR complex component RAPTOR1B , indicating that auxin is upstream of TOR in the regulation of autophagy. We conclude that repression of auxin-regulated TOR activity is required for autophagy activation in response to a subset of abiotic stress conditions.

  18. The NH2 terminus regulates voltage-dependent gating of CALHM ion channels.

    Science.gov (United States)

    Tanis, Jessica E; Ma, Zhongming; Foskett, J Kevin

    2017-08-01

    Calcium homeostasis modulator protein-1 (CALHM1) and its Caenorhabditis elegans (ce) homolog, CLHM-1, belong to a new family of physiologically important ion channels that are regulated by voltage and extracellular Ca 2+ (Ca 2+ o ) but lack a canonical voltage-sensing domain. Consequently, the intrinsic voltage-dependent gating mechanisms for CALHM channels are unknown. Here, we performed voltage-clamp experiments on ceCLHM-1 chimeric, deletion, insertion, and point mutants to assess the role of the NH 2 terminus (NT) in CALHM channel gating. Analyses of chimeric channels in which the ceCLHM-1 and human (h)CALHM1 NH 2 termini were interchanged showed that the hCALHM1 NT destabilized channel-closed states, whereas the ceCLHM-1 NT had a stabilizing effect. In the absence of Ca 2+ o , deletion of up to eight amino acids from the ceCLHM-1 NT caused a hyperpolarizing shift in the conductance-voltage relationship with little effect on voltage-dependent slope. However, deletion of nine or more amino acids decreased voltage dependence and induced a residual conductance at hyperpolarized voltages. Insertion of amino acids into the NH 2 -terminal helix also decreased voltage dependence but did not prevent channel closure. Mutation of ceCLHM-1 valine 9 and glutamine 13 altered half-maximal activation and voltage dependence, respectively, in 0 Ca 2+ In 2 mM Ca 2+ o , ceCLHM-1 NH 2 -terminal deletion and point mutant channels closed completely at hyperpolarized voltages with apparent affinity for Ca 2+ o indistinguishable from wild-type ceCLHM-1, although the ceCLHM-1 valine 9 mutant exhibited an altered conductance-voltage relationship and kinetics. We conclude that the NT plays critical roles modulating voltage dependence and stabilizing the closed states of CALHM channels. Copyright © 2017 the American Physiological Society.

  19. p53- and ERK7-dependent ribosome surveillance response regulates Drosophila insulin-like peptide secretion.

    Directory of Open Access Journals (Sweden)

    Kiran Hasygar

    2014-11-01

    Full Text Available Insulin-like signalling is a conserved mechanism that coordinates animal growth and metabolism with nutrient status. In Drosophila, insulin-producing median neurosecretory cells (IPCs regulate larval growth by secreting insulin-like peptides (dILPs in a diet-dependent manner. Previous studies have shown that nutrition affects dILP secretion through humoral signals derived from the fat body. Here we uncover a novel mechanism that operates cell autonomously in the IPCs to regulate dILP secretion. We observed that impairment of ribosome biogenesis specifically in the IPCs strongly inhibits dILP secretion, which consequently leads to reduced body size and a delay in larval development. This response is dependent on p53, a known surveillance factor for ribosome biogenesis. A downstream effector of this growth inhibitory response is an atypical MAP kinase ERK7 (ERK8/MAPK15, which is upregulated in the IPCs following impaired ribosome biogenesis as well as starvation. We show that ERK7 is sufficient and essential to inhibit dILP secretion upon impaired ribosome biogenesis, and it acts epistatically to p53. Moreover, we provide evidence that p53 and ERK7 contribute to the inhibition of dILP secretion upon starvation. Thus, we conclude that a cell autonomous ribosome surveillance response, which leads to upregulation of ERK7, inhibits dILP secretion to impede tissue growth under limiting dietary conditions.

  20. Nutritional regulation of IGF-II, but not IGF-I, is age dependent in sheep.

    Science.gov (United States)

    Oldham, J M; Martyn, J A; Hua, K M; MacDonald, N A; Hodgkinson, S C; Bass, J J

    1999-12-01

    In post-natal animals, plasma concentrations of IGF-I are tightly regulated by nutritional status. The current study reports that plasma levels of IGF-II in sheep are also regulated by nutrition, but whether plasma IGF-II is increased, decreased or remains the same, depends on the age of the animal. Ewe lambs, ranging in age from 2 days to 2 years, were fed or fasted for lengths of time between 24 and 72 h. Blood samples were taken at intervals of 24 h throughout the treatment period and immediately before slaughter. Plasma concentrations of IGF-I increased with advancing age in fed animals (Panimals matured (Pnutrition (Panimals (Panimals (Pnutritional sensitivity of serum IGF-binding proteins (BPs) also changed with age. The 29 kDa BP, which we presume to be BP1, was elevated by fasting in young animals and reduced slightly in older animals. BP2 was increased to a similar magnitude by fasting at all ages. BP3 was depressed by fasting in young animals and showed little change in adults. In contrast, a 24 kDa BP, which is probably BP4, showed little change in young animals and was reduced substantially in older sheep. In conclusion, the response of plasma IGF-II to fasting suggests that this peptide has functions in mediating nutritional stress which depend on the age of the animal, and also that the role of IGF-II may differ from that of IGF-I in adults.

  1. RhoG regulates anoikis through a phosphatidylinositol 3-kinase-dependent mechanism

    International Nuclear Information System (INIS)

    Yamaki, Nao; Negishi, Manabu; Katoh, Hironori

    2007-01-01

    In normal epithelial cells, cell-matrix interaction is required for cell survival and proliferation, whereas disruption of this interaction causes epithelial cells to undergo apoptosis called anoikis. Here we show that the small GTPase RhoG plays an important role in the regulation of anoikis. HeLa cells are capable of anchorage-independent cell growth and acquire resistance to anoikis. We found that RNA interference-mediated knockdown of RhoG promoted anoikis in HeLa cells. Previous studies have shown that RhoG activates Rac1 and induces several cellular functions including promotion of cell migration through its effector ELMO and the ELMO-binding protein Dock180 that function as a Rac-specific guanine nucleotide exchange factor. However, RhoG-induced suppression of anoikis was independent of the ELMO- and Dock180-mediated activation of Rac1. On the other hand, the regulation of anoikis by RhoG required phosphatidylinositol 3-kinase (PI3K) activity, and constitutively active RhoG bound to the PI3K regulatory subunit p85α and induced the PI3K-dependent phosphorylation of Akt. Taken together, these results suggest that RhoG protects cells from apoptosis caused by the loss of anchorage through a PI3K-dependent mechanism, independent of its activation of Rac1

  2. TALE activators regulate gene expression in a position- and strand-dependent manner in mammalian cells.

    Science.gov (United States)

    Uhde-Stone, Claudia; Cheung, Edna; Lu, Biao

    2014-01-24

    Transcription activator-like effectors (TALEs) are a class of transcription factors that are readily programmable to regulate gene expression. Despite their growing popularity, little is known about binding site parameters that influence TALE-mediated gene activation in mammalian cells. We demonstrate that TALE activators modulate gene expression in mammalian cells in a position- and strand-dependent manner. To study the effects of binding site location, we engineered TALEs customized to recognize specific DNA sequences located in either the promoter or the transcribed region of reporter genes. We found that TALE activators robustly activated reporter genes when their binding sites were located within the promoter region. In contrast, TALE activators inhibited the expression of reporter genes when their binding sites were located on the sense strand of the transcribed region. Notably, this repression was independent of the effector domain utilized, suggesting a simple blockage mechanism. We conclude that TALE activators in mammalian cells regulate genes in a position- and strand-dependent manner that is substantially different from gene activation by native TALEs in plants. These findings have implications for optimizing the design of custom TALEs for genetic manipulation in mammalian cells. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Calcium/calmodulin-dependent protein kinase II activity regulates the proliferative potential of growth plate chondrocytes.

    Science.gov (United States)

    Li, Yuwei; Ahrens, Molly J; Wu, Amy; Liu, Jennifer; Dudley, Andrew T

    2011-01-01

    For tissues that develop throughout embryogenesis and into postnatal life, the generation of differentiated cells to promote tissue growth is at odds with the requirement to maintain the stem cell/progenitor cell population to preserve future growth potential. In the growth plate cartilage, this balance is achieved in part by establishing a proliferative phase that amplifies the number of progenitor cells prior to terminal differentiation into hypertrophic chondrocytes. Here, we show that endogenous calcium/calmodulin-dependent protein kinase II (CamkII, also known as Camk2) activity is upregulated prior to hypertrophy and that loss of CamkII function substantially blocks the transition from proliferation to hypertrophy. Wnt signaling and Pthrp-induced phosphatase activity negatively regulate CamkII activity. Release of this repression results in activation of multiple effector pathways, including Runx2- and β-catenin-dependent pathways. We present an integrated model for the regulation of proliferation potential by CamkII activity that has important implications for studies of growth control and adult progenitor/stem cell populations.

  4. Polycomb Group Protein PHF1 Regulates p53-dependent Cell Growth Arrest and Apoptosis*

    Science.gov (United States)

    Yang, Yang; Wang, Chenji; Zhang, Pingzhao; Gao, Kun; Wang, Dejie; Yu, Hongxiu; Zhang, Ting; Jiang, Sirui; Hexige, Saiyin; Hong, Zehui; Yasui, Akira; Liu, Jun O.; Huang, Haojie; Yu, Long

    2013-01-01

    Polycomb group protein PHF1 is well known as a component of a novel EED-EZH2·Polycomb repressive complex 2 complex and plays important roles in H3K27 methylation and Hox gene silencing. PHF1 is also involved in the response to DNA double-strand breaks in human cells, promotes nonhomologous end-joining processes through interaction with Ku70/Ku80. Here, we identified another function of PHF1 as a potential p53 pathway activator in a pathway screen using luminescence reporter assay. Subsequent studies showed PHF1 directly interacts with p53 proteins both in vivo and in vitro and co-localized in nucleus. PHF1 binds to the C-terminal regulatory domain of p53. Overexpression of PHF1 elevated p53 protein level and prolonged its turnover. Knockdown of PHF1 reduced p53 protein level and its target gene expression both in normal state and DNA damage response. Mechanically, PHF1 protects p53 proteins from MDM2-mediated ubiquitination and degradation. Furthermore, we showed that PHF1 regulates cell growth arrest and etoposide-induced apoptosis in a p53-dependent manner. Finally, PHF1 expression was significantly down-regulated in human breast cancer samples. Taken together, we establish PHF1 as a novel positive regulator of the p53 pathway. These data shed light on the potential roles of PHF1 in tumorigenesis and/or tumor progression. PMID:23150668

  5. Growth-Rate Dependent Regulation of tRNA Level and Charging in Bacillus licheniformis.

    Science.gov (United States)

    Ferro, Iolanda; Liebeton, Klaus; Ignatova, Zoya

    2017-10-13

    Cellular growth crucially depends on protein synthesis and the abundance of translational components. Among them, aminoacyl-tRNAs play a central role in biosynthesis and shape the kinetics of mRNA translation, thus influencing protein production. Here, we used microarray-based approaches to determine the charging levels and tRNA abundance of Bacillus licheniformis. We observed an interesting cross-talk among tRNA expression, charging pattern, and growth rate. For a large subset of tRNAs, we found a co-regulated and augmented expression at high growth rate. Their tRNA aminoacylation level is kept relatively constant through riboswitch-regulated expression of the cognate aminoacyl-tRNA-synthetase (AARS). We show that AARSs with putative riboswitch-controlled expression are those charging tRNAs with amino acids which disfavor cell growth when individually added to the nutrient medium. Our results suggest that the riboswitch-regulated AARS expression in B. licheniformis is a powerful mechanism not only to maintain a constant ratio of aminoacyl-tRNA independent of the growth rate but concomitantly to control the intracellular level of free amino acids. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Phosphorylation-dependent down-regulation of apolipoprotein A5 by insulin

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, Maxine; Helleboid-Chapman, Audrey; Jakel, Heidelinde; Rommens, Corinne; Martin, Genevieve; Duran-Sandoval, Daniel; Staels, Bart; Rubin, Edward M.; Pennacchio, Len A.; Taskinen, Marja-Riitta; Fruchart-Najib, Jamila; Fruchart, Jean-Charles

    2004-02-15

    The apolipoprotein A5 (APOA5) gene has been shown to be important in lowering plasma triglyceride levels. Since several studies have shown that hyperinsulinemia is associated with hypertriglyceridemia, we sought to determine whether APOA5 gene is regulated by insulin. We show here that cell and mouse treatments with insulin down-regulated APOA5 expression in a dose-dependent manner. Furthermore, we determined that insulin decreases APOA5 promoter activity and subsequent deletion analyses revealed an E-box-containing fragment. We showed that Upstream Stimulatory Factors, USF1/USF2, bind to the identified E-box in the APOA5 promoter. Moreover, in cotransfection studies, USF1 stimulates APOA5 promoter activity. The treatment with insulin reduces the binding of USF1/USF2 to APOA5 promoter. The inhibition of PI3K pathway with wortmannin abolished the insulin s effect on APOA5 gene transcription. Using oligoprecipitation method of USF from nuclear extracts, we demonstrated that phosphorylated USF1 failed to bind to APOA5 promoter. This indicates that the APOA5 gene transrepression by insulin involves a phosphorylation of USF through PI3K, that modulate their binding to APOA5 promoter and results in APOA5 down-regulation. The effect of exogenous hyperinsulinemia in healthy men shows a decrease of the plasma ApoAV level. These data suggest a potential mechanism involving APOA5 gene in hypertriglyceridemia associated with hyperinsulinemia.

  7. Interaction with epsin 1 regulates the constitutive clathrin-dependent internalization of ErbB3.

    Science.gov (United States)

    Szymanska, Monika; Fosdahl, Anne Marthe; Raiborg, Camilla; Dietrich, Markus; Liestøl, Knut; Stang, Espen; Bertelsen, Vibeke

    2016-06-01

    In contrast to other members of the EGF receptor family, ErbB3 is constitutively internalized in a clathrin-dependent manner. Previous studies have shown that ErbB3 does not interact with the coated pit localized adaptor complex 2 (AP-2), and that ErbB3 lacks two AP-2 interacting internalization signals identified in the EGF receptor. Several other clathrin-associated sorting proteins which may recruit cargo into coated pits have, however, been identified, and the study was performed to identify adaptors needed for constitutive internalization of ErbB3. A high-throughput siRNA screen was used to identify adaptor proteins needed for internalization of ErbB3. Upon knock-down of candidate proteins internalization of ErbB3 was identified using an antibody-based internalization assay combined with automatic fluorescence microscopy. Among 29 candidates only knock-down of epsin 1 turned out to inhibit ErbB3. Epsin 1 has ubiquitin interacting motifs (UIMs) and we show that ErbB3 interacts with an epsin 1 deletion mutant containing these UIMs. In support of an ErbB3-epsin 1 UIM dependent interaction, we show that ErbB3 is constitutively ubiquitinated, but that both ubiquitination and the ErbB3-epsin 1 interaction increase upon ligand binding. Altogether the results are consistent with a model whereby both constitutive and ligand-induced internalization of ErbB3 are regulated through interaction with epsin 1. Internalization is an important regulator of growth factor receptor mediated signaling and the current study identify mechanisms regulating plasma membrane turnover of ErbB3. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Regulation of p73 by Hck through kinase-dependent and independent mechanisms

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    Radha Vegesna

    2007-05-01

    Full Text Available Abstract Background p73, a p53 family member is a transcription factor that plays a role in cell cycle, differentiation and apoptosis. p73 is regulated through post translational modifications and protein interactions. c-Abl is the only known tyrosine kinase that phosphorylates and activates p73. Here we have analyzed the role of Src family kinases, which are involved in diverse signaling pathways, in regulating p73. Results Exogenously expressed as well as cellular Hck and p73 interact in vivo. In vitro binding assays show that SH3 domain of Hck interacts with p73. Co-expression of p73 with Hck or c-Src in mammalian cells resulted in tyrosine phosphorylation of p73. Using site directed mutational analysis, we determined that Tyr-28 was the major site of phosphorylation by Hck and c-Src, unlike c-Abl which phosphorylates Tyr-99. In a kinase dependent manner, Hck co-expression resulted in stabilization of p73 protein in the cytoplasm. Activation of Hck in HL-60 cells resulted in tyrosine phosphorylation of endogenous p73. Both exogenous and endogenous Hck localize to the nuclear as well as cytoplasmic compartment, just as does p73. Ectopically expressed Hck repressed the transcriptional activity of p73 as determined by promoter assays and semi-quantitative RT-PCR analysis of the p73 target, Ipaf and MDM2. SH3 domain- dependent function of Hck was required for its effect on p73 activity, which was also reflected in its ability to inhibit p73-mediated apoptosis. We also show that Hck interacts with Yes associated protein (YAP, a transcriptional co-activator of p73, and shRNA mediated knockdown of YAP protein reduces p73 induced Ipaf promoter activation. Conclusion We have identified p73 as a novel substrate and interacting partner of Hck and show that it regulates p73 through mechanisms that are dependent on either catalytic activity or protein interaction domains. Hck-SH3 domain-mediated interactions play an important role in the inhibition of p73

  9. Emotion regulation and substance use frequency in women with substance dependence and borderline personality disorder receiving dialectical behavior therapy.

    Science.gov (United States)

    Axelrod, Seth R; Perepletchikova, Francheska; Holtzman, Kevin; Sinha, Rajita

    2011-01-01

    Dialectical behavior therapy (DBT) identifies emotion dysregulation as central to the dangerous impulsivity of borderline personality disorder (BPD) including substance use disorders, and DBT targets improved emotion regulation as a primary mechanism of change. However, improved emotion regulation with DBT and associations between such improvement and behavioral outcomes such as substance use has not been previously reported. Thus, the goal of this study was to assess for improvement in emotion regulation and to examine the relationship between improvements in the emotion regulation and substance use problems following DBT treatment. Emotion regulation as assessed by the Difficulties in Emotion Regulation Scale, depressed mood as assessed by the Beck Depression Inventory, and their associations with substance use frequency were investigated in 27 women with substance dependence and BPD receiving 20 weeks of DBT in an academic community outpatient substance abuse treatment program. Results indicated improved emotion regulation, improved mood, and decreased substance use frequency. Further, emotion regulation improvement, but not improved mood, explained the variance of decreased substance use frequency. This is the first study to demonstrate improved emotion regulation in BPD patients treated with DBT and to show that improved emotion regulation can account for increased behavioral control in BPD patients. SIGNIFICANCE AND FUTURE RESEARCH: Emotion regulation assessment is recommended for future studies to further clarify the etiology and maintenance of disorders associated with emotional dysregulation such as BPD and substance dependence and to further explore emotion regulation as a potential mechanism of change for clinical interventions.

  10. The dependence of neuronal encoding efficiency on Hebbian plasticity and homeostatic regulation of neurotransmitter release

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    Faramarz eFaghihi

    2015-04-01

    Full Text Available Synapses act as information filters by different molecular mechanisms including retrograde messenger that affect neuronal spiking activity. One of the well-known effects of retrograde messenger in presynaptic neurons is a change of the probability of neurotransmitter release. Hebbian learning describe a strengthening of a synapse between a presynaptic input onto a postsynaptic neuron when both pre- and postsynaptic neurons are coactive. In this work, a theory of homeostatic regulation of neurotransmitter release by retrograde messenger and Hebbian plasticity in neuronal encoding is presented. Encoding efficiency was measured for different synaptic conditions. In order to gain high encoding efficiency, the spiking pattern of a neuron should be dependent on the intensity of the input and show low levels of noise. In this work, we represent spiking trains as zeros and ones (corresponding to non-spike or spike in a time bin, respectively as words with length equal to three. Then the frequency of each word (here eight words is measured using spiking trains. These frequencies are used to measure neuronal efficiency in different conditions and for different parameter values. Results show that neurons that have synapses acting as band-pass filters show the highest efficiency to encode their input when both Hebbian mechanism and homeostatic regulation of neurotransmitter release exist in synapses. Specifically, the integration of homeostatic regulation of feedback inhibition with Hebbian mechanism and homeostatic regulation of neurotransmitter release in the synapses leads to even higher efficiency when high stimulus intensity is presented to the neurons. However, neurons with synapses acting as high-pass filters show no remarkable increase in encoding efficiency for all simulated synaptic plasticity mechanisms.

  11. SPAK Dependent Regulation of Peptide Transporters PEPT1 and PEPT2

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    Jamshed Warsi

    2014-10-01

    Full Text Available Background/Aims: SPAK (STE20-related proline/alanine-rich kinase is a powerful regulator of renal tubular ion transport and blood pressure. Moreover, SPAK contributes to the regulation of cell volume. Little is known, however, about a role of SPAK in the regulation or organic solutes. The present study thus addressed the influence of SPAK on the peptide transporters PEPT1 and PEPT2. Methods: To this end, cRNA encoding PEPT1 or PEPT2 were injected into Xenopus laevis oocytes without or with additional injection of cRNA encoding wild-type, SPAK, WNK1 insensitive inactive T233ASPAK, constitutively active T233ESPAK, and catalytically inactive D212ASPAK. Electrogenic peptide (glycine-glycine transport was determined by dual electrode voltage clamp and PEPT2 protein abundance in the cell membrane by chemiluminescence. Intestinal electrogenic peptide transport was estimated from peptide induced current in Ussing chamber experiments of jejunal segments isolated from gene targeted mice expressing SPAK resistant to WNK-dependent activation (spaktg/tg and respective wild-type mice (spak+/+. Results: In PEPT1 and in PEPT2 expressing oocytes, but not in oocytes injected with water, the dipeptide gly-gly (2 mM generated an inward current, which was significantly decreased following coexpression of SPAK. The effect of SPAK on PEPT1 was mimicked by T233ESPAK, but not by D212ASPAK or T233ASPAK. SPAK decreased maximal peptide induced current of PEPT1. Moreover, SPAK decreased carrier protein abundance in the cell membrane of PEPT2 expressing oocytes. In intestinal segments gly-gly generated a current, which was significantly higher in spaktg/tg than in spak+/+ mice. Conclusion: SPAK is a powerful regulator of peptide transporters PEPT1 and PEPT2.

  12. Pacemaker neuron and network oscillations depend on a neuromodulator-regulated linear current

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    Shunbing Zhao

    2010-05-01

    Full Text Available Linear leak currents have been implicated in the regulation of neuronal excitability, generation of neuronal and network oscillations, and network state transitions. Yet, few studies have directly tested the dependence of network oscillations on leak currents or explored the role of leak currents on network activity. In the oscillatory pyloric network of decapod crustaceans neuromodulatory inputs are necessary for pacemaker activity. A large subset of neuromodulators is known to activate a single voltage-gated inward current IMI, which has been shown to regulate the rhythmic activity of the network and its pacemaker neurons. Using the dynamic clamp technique, we show that the crucial component of IMI for the generation of oscillatory activity is only a close-to-linear portion of the current-voltage relationship. The nature of this conductance is such that the presence or the absence of neuromodulators effectively regulates the amount of leak current and the input resistance in the pacemaker neurons. When deprived of neuromodulatory inputs, pyloric oscillations are disrupted; yet, a linear reduction of the total conductance in a single neuron within the pacemaker group recovers not only the pacemaker activity in that neuron, but also leads to a recovery of oscillations in the entire pyloric network. The recovered activity produces proper frequency and phasing that is similar to that induced by neuromodulators. These results show that the passive properties of pacemaker neurons can significantly affect their capacity to generate and regulate the oscillatory activity of an entire network, and that this feature is exploited by neuromodulatory inputs.

  13. Effects of phosphodiesterase III inhibition on length-dependent regulation of myocardial function in coronary surgery patients

    NARCIS (Netherlands)

    de Hert, S. G.; ten Broecke, P. W.; Mertens, E.; Rodrigus, I. E.; Stockman, B. A.

    2002-01-01

    BACKGROUND: Phosphodiesterase III inhibitors increase myocardial contractility and decrease left ventricular (LV) afterload. We studied whether these effects altered LV response to an increase in cardiac load and affected length-dependent regulation of myocardial function. METHODS: Before the start

  14. Calcium Co-regulates Oxidative Metabolism and ATP Synthase-dependent Respiration in Pancreatic Beta Cells

    Science.gov (United States)

    De Marchi, Umberto; Thevenet, Jonathan; Hermant, Aurelie; Dioum, Elhadji; Wiederkehr, Andreas

    2014-01-01

    Mitochondrial energy metabolism is essential for glucose-induced calcium signaling and, therefore, insulin granule exocytosis in pancreatic beta cells. Calcium signals are sensed by mitochondria acting in concert with mitochondrial substrates for the full activation of the organelle. Here we have studied glucose-induced calcium signaling and energy metabolism in INS-1E insulinoma cells and human islet beta cells. In insulin secreting cells a surprisingly large fraction of total respiration under resting conditions is ATP synthase-independent. We observe that ATP synthase-dependent respiration is markedly increased after glucose stimulation. Glucose also causes a very rapid elevation of oxidative metabolism as was followed by NAD(P)H autofluorescence. However, neither the rate of the glucose-induced increase nor the new steady-state NAD(P)H levels are significantly affected by calcium. Our findings challenge the current view, which has focused mainly on calcium-sensitive dehydrogenases as the target for the activation of mitochondrial energy metabolism. We propose a model of tight calcium-dependent regulation of oxidative metabolism and ATP synthase-dependent respiration in beta cell mitochondria. Coordinated activation of matrix dehydrogenases and respiratory chain activity by calcium allows the respiratory rate to change severalfold with only small or no alterations of the NAD(P)H/NAD(P)+ ratio. PMID:24554722

  15. Impaired Na⁺-dependent regulation of acetylcholine-activated inward-rectifier K⁺ current modulates action potential rate dependence in patients with chronic atrial fibrillation.

    Science.gov (United States)

    Voigt, Niels; Heijman, Jordi; Trausch, Anne; Mintert-Jancke, Elisa; Pott, Lutz; Ravens, Ursula; Dobrev, Dobromir

    2013-08-01

    Shortened action-potential duration (APD) and blunted APD rate adaptation are hallmarks of chronic atrial fibrillation (cAF). Basal and muscarinic (M)-receptor-activated inward-rectifier K(+) currents (IK1 and IK,ACh, respectively) contribute to regulation of human atrial APD and are subject to cAF-dependent remodeling. Intracellular Na(+) ([Na(+)]i) enhances IK,ACh in experimental models but the effect of [Na(+)]i-dependent regulation of inward-rectifier K(+) currents on APD in human atrial myocytes is currently unknown. Here, we report a [Na(+)]i-dependent inhibition of outward IK1 in atrial myocytes from sinus rhythm (SR) or cAF patients. In contrast, IK,ACh activated by carbachol, a non-selective M-receptor agonist, increased with elevation of [Na(+)]i in SR. This [Na(+)]i-dependent IK,ACh regulation was absent in cAF. Including [Na(+)]i dependence of IK1 and IK,ACh in a recent computational model of the human atrial myocyte revealed that [Na(+)]i accumulation at fast rates inhibits IK1 and blunts physiological APD rate dependence in both groups. [Na(+)]i-dependent IK,ACh augmentation at fast rates increased APD rate dependence in SR, but not in cAF. These results identify impaired Na(+)-sensitivity of IK,ACh as one potential mechanism contributing to the blunted APD rate dependence in patients with cAF. This article is part of a Special Issue entitled "Na(+) Regulation in Cardiac Myocytes". Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  16. Regulating NETosis: Increasing pH Promotes NADPH Oxidase-Dependent NETosis

    Science.gov (United States)

    Khan, Meraj A.; Philip, Lijy M.; Cheung, Guillaume; Vadakepeedika, Shawn; Grasemann, Hartmut; Sweezey, Neil; Palaniyar, Nades

    2018-01-01

    Neutrophils migrating from the blood (pH 7.35–7.45) into the surrounding tissues encounter changes in extracellular pH (pHe) conditions. Upon activation of NADPH oxidase 2 (Nox), neutrophils generate large amounts of H+ ions reducing the intracellular pH (pHi). Nevertheless, how extracellular pH regulates neutrophil extracellular trap (NET) formation (NETosis) is not clearly established. We hypothesized that increasing pH increases Nox-mediated production of reactive oxygen species (ROS) and neutrophil protease activity, stimulating NETosis. Here, we found that raising pHe (ranging from 6.6 to 7.8; every 0.2 units) increased pHi of both activated and resting neutrophils within 10–20 min (Seminaphtharhodafluor dual fluorescence measurements). Since Nox activity generates H+ ions, pHi is lower in neutrophils that are activated compared to resting. We also found that higher pH stimulated Nox-dependent ROS production (R123 generation; flow cytometry, plate reader assay, and imaging) during spontaneous and phorbol myristate acetate-induced NETosis (Sytox Green assays, immunoconfocal microscopy, and quantifying NETs). In neutrophils that are activated and not resting, higher pH stimulated histone H4 cleavage (Western blots) and NETosis. Raising pH increased Escherichia coli lipopolysaccharide-, Pseudomonas aeruginosa (Gram-negative)-, and Staphylococcus aureus (Gram-positive)-induced NETosis. Thus, higher pHe promoted Nox-dependent ROS production, protease activity, and NETosis; lower pH has the opposite effect. These studies provided mechanistic steps of pHe-mediated regulation of Nox-dependent NETosis. Raising pH either by sodium bicarbonate or Tris base (clinically known as Tris hydroxymethyl aminomethane, tromethamine, or THAM) increases NETosis. Each Tris molecule can bind 3H+ ions, whereas each bicarbonate HCO3− ion binds 1H+ ion. Therefore, the amount of Tris solution required to cause the same increase in pH level is less than that of equimolar

  17. Regulating NETosis: Increasing pH Promotes NADPH Oxidase-Dependent NETosis

    Directory of Open Access Journals (Sweden)

    Meraj A. Khan

    2018-02-01

    Full Text Available Neutrophils migrating from the blood (pH 7.35–7.45 into the surrounding tissues encounter changes in extracellular pH (pHe conditions. Upon activation of NADPH oxidase 2 (Nox, neutrophils generate large amounts of H+ ions reducing the intracellular pH (pHi. Nevertheless, how extracellular pH regulates neutrophil extracellular trap (NET formation (NETosis is not clearly established. We hypothesized that increasing pH increases Nox-mediated production of reactive oxygen species (ROS and neutrophil protease activity, stimulating NETosis. Here, we found that raising pHe (ranging from 6.6 to 7.8; every 0.2 units increased pHi of both activated and resting neutrophils within 10–20 min (Seminaphtharhodafluor dual fluorescence measurements. Since Nox activity generates H+ ions, pHi is lower in neutrophils that are activated compared to resting. We also found that higher pH stimulated Nox-dependent ROS production (R123 generation; flow cytometry, plate reader assay, and imaging during spontaneous and phorbol myristate acetate-induced NETosis (Sytox Green assays, immunoconfocal microscopy, and quantifying NETs. In neutrophils that are activated and not resting, higher pH stimulated histone H4 cleavage (Western blots and NETosis. Raising pH increased Escherichia coli lipopolysaccharide-, Pseudomonas aeruginosa (Gram-negative-, and Staphylococcus aureus (Gram-positive-induced NETosis. Thus, higher pHe promoted Nox-dependent ROS production, protease activity, and NETosis; lower pH has the opposite effect. These studies provided mechanistic steps of pHe-mediated regulation of Nox-dependent NETosis. Raising pH either by sodium bicarbonate or Tris base (clinically known as Tris hydroxymethyl aminomethane, tromethamine, or THAM increases NETosis. Each Tris molecule can bind 3H+ ions, whereas each bicarbonate HCO3− ion binds 1H+ ion. Therefore, the amount of Tris solution required to cause the same increase in pH level is less than that of equimolar

  18. Regulation of singlet oxygen-induced apoptosis by cytosolic NADP+-dependent isocitrate dehydrogenase.

    Science.gov (United States)

    Kim, Sun Yee; Lee, Su Min; Tak, Jean Kyoung; Choi, Kyeong Sook; Kwon, Taeg Kyu; Park, Jeen-Woo

    2007-08-01

    Singlet oxygen is a highly reactive form of molecular oxygen that may harm living systems by oxidizing critical cellular macromolecules and it also promotes deleterious processes such as cell death. Recently, we demonstrated that the control of redox balance and the cellular defense against oxidative damage are the primary functions of cytosolic NADP(+)-dependent isocitrate dehydrogenase (IDPc) through supplying NADPH for antioxidant systems. In this report, we demonstrate that modulation of IDPc activity in HL-60 cells regulates singlet oxygen-induced apoptosis. When we examined the protective role of IDPc against singlet oxygen-induced apoptosis with HL-60 cells transfected with the cDNA for mouse IDPc in sense and antisense orientations, a clear inverse relationship was observed between the amount of IDPc expressed in target cells and their susceptibility to apoptosis. The results suggest that IDPc plays an important protective role in apoptosis of HL-60 cells induced by singlet oxygen.

  19. Protein kinase C-dependent regulation of connexin43 gap junctions and hemichannels

    DEFF Research Database (Denmark)

    Alstrøm, Jette Skov; Stroemlund, Line Waring; Nielsen, Morten Schak

    2015-01-01

    Connexin43 (Cx43) generates intercellular gap junction channels involved in, among others, cardiac and brain function. Gap junctions are formed by the docking of two hemichannels from neighbouring cells. Undocked Cx43 hemichannels can upon different stimuli open towards the extracellular matrix...... and allow transport of molecules such as fluorescent dyes and ATP. A range of phosphorylated amino acids have been detected in the C-terminus of Cx43 and their physiological role has been intensively studied both in the gap junctional form of Cx43 and in its hemichannel configuration. We present the current...... knowledge of protein kinase C (PKC)-dependent regulation of Cx43 and discuss the divergent results....

  20. HJURP regulates cellular senescence in human fibroblasts and endothelial cells via a p53-dependent pathway.

    Science.gov (United States)

    Heo, Jong-Ik; Cho, Jung Hee; Kim, Jae-Ryong

    2013-08-01

    Holliday junction recognition protein (HJURP), a centromere protein-A (CENP-A) histone chaperone, mediates centromere-specific assembly of CENP-A nucleosome, contributing to high-fidelity chromosome segregation during cell division. However, the role of HJURP in cellular senescence of human primary cells remains unclear. We found that the expression levels of HJURP decreased in human dermal fibroblasts and umbilical vein endothelial cells in replicative or premature senescence. Ectopic expression of HJURP in senescent cells partially overcame cell senescence. Conversely, downregulation of HJURP in young cells led to premature senescence. p53 knockdown, but not p16 knockdown, abolished senescence phenotypes caused by HJURP reduction. These data suggest that HJURP plays an important role in the regulation of cellular senescence through a p53-dependent pathway and might contribute to tissue or organismal aging and protection of cellular transformation.

  1. Essential role of TGF-beta/Smad pathway on statin dependent vascular smooth muscle cell regulation.

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    Juan Rodríguez-Vita

    Full Text Available BACKGROUND: The 3-hydroxy-3-methylglutaryl CoA reductase inhibitors (also called statins exert proven beneficial effects on cardiovascular diseases. Recent data suggest a protective role for Transforming Growth Factor-beta (TGF-beta in atherosclerosis by regulating the balance between inflammation and extracellular matrix accumulation. However, there are no studies about the effect of statins on TGF-beta/Smad pathway in atherosclerosis and vascular cells. METHODOLOGY: In cultured vascular smooth muscle cells (VSMCs statins enhanced Smad pathway activation caused by TGF-beta. In addition, statins upregulated TGF-beta receptor type II (TRII, and increased TGF-beta synthesis and TGF-beta/Smad-dependent actions. In this sense, statins, through Smad activation, render VSMCs more susceptible to TGF-beta induced apoptosis and increased TGF-beta-mediated ECM production. It is well documented that high doses of statins induce apoptosis in cultured VSMC in the presence of serum; however the precise mechanism of this effect remains to be elucidated. We have found that statins-induced apoptosis was mediated by TGF-beta/Smad pathway. Finally, we have described that RhoA inhibition is a common intracellular mechanisms involved in statins effects. The in vivo relevance of these findings was assessed in an experimental model of atherosclerosis in apolipoprotein E deficient mice: Treatment with Atorvastatin increased Smad3 phosphorylation and TRII overexpression, associated to elevated ECM deposition in the VSMCs within atheroma plaques, while apoptosis was not detected. CONCLUSIONS: Statins enhance TGF-beta/Smad pathway, regulating ligand levels, receptor, main signaling pathway and cellular responses of VSMC, including apoptosis and ECM accumulation. Our findings show that TGF-beta/Smad pathway is essential for statins-dependent actions in VSMCs.

  2. MicroRNA-dependent regulation of transcription in non-small cell lung cancer.

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    Sonia Molina-Pinelo

    Full Text Available Squamous cell lung cancer (SCC and adenocarcinoma are the most common histological subtypes of non-small cell lung cancer (NSCLC, and have been traditionally managed in the clinic as a single entity. Increasing evidence, however, illustrates the biological diversity of these two histological subgroups of lung cancer, and supports the need to improve our understanding of the molecular basis beyond the different phenotypes if we aim to develop more specific and individualized targeted therapy. The purpose of this study was to identify microRNA (miRNA-dependent transcriptional regulation differences between SCC and adenocarcinoma histological lung cancer subtypes. In this work, paired miRNA (667 miRNAs by TaqMan Low Density Arrays (TLDA and mRNA profiling (Whole Genome 44 K array G112A, Agilent was performed in tumor samples of 44 NSCLC patients. Nine miRNAs and 56 mRNAs were found to be differentially expressed in SCC versus adenocarcinoma samples. Eleven of these 56 mRNA were predicted as targets of the miRNAs identified to be differently expressed in these two histological conditions. Of them, 6 miRNAs (miR-149, miR-205, miR-375, miR-378, miR-422a and miR-708 and 9 target genes (CEACAM6, CGN, CLDN3, ABCC3, MLPH, ACSL5, TMEM45B, MUC1 were validated by quantitative PCR in an independent cohort of 41 lung cancer patients. Furthermore, the inverse correlation between mRNAs and microRNAs expression was also validated. These results suggest miRNA-dependent transcriptional regulation differences play an important role in determining key hallmarks of NSCLC, and may provide new biomarkers for personalized treatment strategies.

  3. Thioredoxin-dependent Redox Regulation of Chloroplastic Phosphoglycerate Kinase from Chlamydomonas reinhardtii*

    Science.gov (United States)

    Morisse, Samuel; Michelet, Laure; Bedhomme, Mariette; Marchand, Christophe H.; Calvaresi, Matteo; Trost, Paolo; Fermani, Simona; Zaffagnini, Mirko; Lemaire, Stéphane D.

    2014-01-01

    In photosynthetic organisms, thioredoxin-dependent redox regulation is a well established mechanism involved in the control of a large number of cellular processes, including the Calvin-Benson cycle. Indeed, 4 of 11 enzymes of this cycle are activated in the light through dithiol/disulfide interchanges controlled by chloroplastic thioredoxin. Recently, several proteomics-based approaches suggested that not only four but all enzymes of the Calvin-Benson cycle may withstand redox regulation. Here, we characterized the redox features of the Calvin-Benson enzyme phosphoglycerate kinase (PGK1) from the eukaryotic green alga Chlamydomonas reinhardtii, and we show that C. reinhardtii PGK1 (CrPGK1) activity is inhibited by the formation of a single regulatory disulfide bond with a low midpoint redox potential (−335 mV at pH 7.9). CrPGK1 oxidation was found to affect the turnover number without altering the affinity for substrates, whereas the enzyme activation appeared to be specifically controlled by f-type thioredoxin. Using a combination of site-directed mutagenesis, thiol titration, mass spectrometry analyses, and three-dimensional modeling, the regulatory disulfide bond was shown to involve the not strictly conserved Cys227 and Cys361. Based on molecular mechanics calculation, the formation of the disulfide is proposed to impose structural constraints in the C-terminal domain of the enzyme that may lower its catalytic efficiency. It is therefore concluded that CrPGK1 might constitute an additional light-modulated Calvin-Benson cycle enzyme with a low activity in the dark and a TRX-dependent activation in the light. These results are also discussed from an evolutionary point of view. PMID:25202015

  4. Activity-Dependent Bidirectional Regulation of GAD Expression in a Homeostatic Fashion Is Mediated by BDNF-Dependent and Independent Pathways

    Science.gov (United States)

    Hanno-Iijima, Yoko; Tanaka, Masami; Iijima, Takatoshi

    2015-01-01

    Homeostatic synaptic plasticity, or synaptic scaling, is a mechanism that tunes neuronal transmission to compensate for prolonged, excessive changes in neuronal activity. Both excitatory and inhibitory neurons undergo homeostatic changes based on synaptic transmission strength, which could effectively contribute to a fine-tuning of circuit activity. However, gene regulation that underlies homeostatic synaptic plasticity in GABAergic (GABA, gamma aminobutyric) neurons is still poorly understood. The present study demonstrated activity-dependent dynamic scaling in which NMDA-R (N-methyl-D-aspartic acid receptor) activity regulated the expression of GABA synthetic enzymes: glutamic acid decarboxylase 65 and 67 (GAD65 and GAD67). Results revealed that activity-regulated BDNF (brain-derived neurotrophic factor) release is necessary, but not sufficient, for activity-dependent up-scaling of these GAD isoforms. Bidirectional forms of activity-dependent GAD expression require both BDNF-dependent and BDNF-independent pathways, both triggered by NMDA-R activity. Additional results indicated that these two GAD genes differ in their responsiveness to chronic changes in neuronal activity, which could be partially caused by differential dependence on BDNF. In parallel to activity-dependent bidirectional scaling in GAD expression, the present study further observed that a chronic change in neuronal activity leads to an alteration in neurotransmitter release from GABAergic neurons in a homeostatic, bidirectional fashion. Therefore, the differential expression of GAD65 and 67 during prolonged changes in neuronal activity may be implicated in some aspects of bidirectional homeostatic plasticity within mature GABAergic presynapses. PMID:26241953

  5. Differential regulation of cyclin-dependent kinase inhibitors in neuroblastoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, Lan [Department of Pediatric Surgery, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Department of Pharmaceutical Sciences, Jilin University, Changchun 130021 (China); Paul, Pritha; Lee, Sora [Department of Pediatric Surgery, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Qiao, Jingbo [Department of Pediatric Surgery, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Wang, Yongsheng [Department of Pharmaceutical Sciences, Jilin University, Changchun 130021 (China); Chung, Dai H., E-mail: dai.chung@vanderbilt.edu [Department of Pediatric Surgery, Vanderbilt University Medical Center, Nashville, TN 37232 (United States); Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN 37232 (United States)

    2013-05-31

    Highlights: •GRP-R signaling differentially regulated the expression of p21 and p27. •Silencing GRP/GRP-R downregulated p21, while p27 expression was upregulated. •Inhibition of GRP/GRP-R signaling enhanced PTEN expression, correlative to the increased expression of p27. •PTEN and p27 co-localized in cytoplasm and silencing PTEN decreased p27 expression. -- Abstract: Gastrin-releasing peptide (GRP) and its receptor (GRP-R) are highly expressed in undifferentiated neuroblastoma, and they play critical roles in oncogenesis. We previously reported that GRP activates the PI3K/AKT signaling pathway to promote DNA synthesis and cell cycle progression in neuroblastoma cells. Conversely, GRP-R silencing induces cell cycle arrest. Here, we speculated that GRP/GRP-R signaling induces neuroblastoma cell proliferation via regulation of cyclin-dependent kinase (CDK) inhibitors. Surprisingly, we found that GRP/GRP-R differentially induced expressions of p21 and p27. Silencing GRP/GRP-R decreased p21, but it increased p27 expressions in neuroblastoma cells. Furthermore, we found that the intracellular localization of p21 and p27 in the nuclear and cytoplasmic compartments, respectively. In addition, we found that GRP/GRP-R silencing increased the expression and accumulation of PTEN in the cytoplasm of neuroblastoma cells where it co-localized with p27, thus suggesting that p27 promotes the function of PTEN as a tumor suppressor by stabilizing PTEN in the cytoplasm. GRP/GRP-R regulation of CDK inhibitors and tumor suppressor PTEN may be critical for tumoriogenesis of neuroblastoma.

  6. Differential regulation of cyclin-dependent kinase inhibitors in neuroblastoma cells

    International Nuclear Information System (INIS)

    Qiao, Lan; Paul, Pritha; Lee, Sora; Qiao, Jingbo; Wang, Yongsheng; Chung, Dai H.

    2013-01-01

    Highlights: •GRP-R signaling differentially regulated the expression of p21 and p27. •Silencing GRP/GRP-R downregulated p21, while p27 expression was upregulated. •Inhibition of GRP/GRP-R signaling enhanced PTEN expression, correlative to the increased expression of p27. •PTEN and p27 co-localized in cytoplasm and silencing PTEN decreased p27 expression. -- Abstract: Gastrin-releasing peptide (GRP) and its receptor (GRP-R) are highly expressed in undifferentiated neuroblastoma, and they play critical roles in oncogenesis. We previously reported that GRP activates the PI3K/AKT signaling pathway to promote DNA synthesis and cell cycle progression in neuroblastoma cells. Conversely, GRP-R silencing induces cell cycle arrest. Here, we speculated that GRP/GRP-R signaling induces neuroblastoma cell proliferation via regulation of cyclin-dependent kinase (CDK) inhibitors. Surprisingly, we found that GRP/GRP-R differentially induced expressions of p21 and p27. Silencing GRP/GRP-R decreased p21, but it increased p27 expressions in neuroblastoma cells. Furthermore, we found that the intracellular localization of p21 and p27 in the nuclear and cytoplasmic compartments, respectively. In addition, we found that GRP/GRP-R silencing increased the expression and accumulation of PTEN in the cytoplasm of neuroblastoma cells where it co-localized with p27, thus suggesting that p27 promotes the function of PTEN as a tumor suppressor by stabilizing PTEN in the cytoplasm. GRP/GRP-R regulation of CDK inhibitors and tumor suppressor PTEN may be critical for tumoriogenesis of neuroblastoma

  7. Differential Dopamine Regulation of Ca2+ Signaling and Its Timing Dependence in the Nucleus Accumbens

    Directory of Open Access Journals (Sweden)

    Immani Swapna

    2016-04-01

    Full Text Available Dopamine action in the nucleus accumbens (NAc is thought to drive appetitive behavior and Pavlovian reward learning. However, it remains controversial how dopamine achieves these behavioral effects by regulating medium spiny projection neurons (MSNs of the NAc, especially on a behaviorally relevant timescale. Metabotropic glutamate receptor (mGluR-induced Ca2+ signaling dependent on the Ca2+- releasing messenger inositol 1,4,5-triphosphate (IP3 plays a critical role in controlling neuronal excitability and synaptic plasticity. Here, we show that transient dopamine application facilitates mGluR/IP3-induced Ca2+ signals within a time window of ∼2–10 s in a subpopulation of MSNs in the NAc core. Dopamine facilitation of IP3-induced Ca2+ signaling is mediated by D1 dopamine receptors. In dopamine-insensitive MSNs, activation of A2A adenosine receptors causes enhancement of IP3-evoked Ca2+ signals, which is reversed by D2 dopamine receptor activation. These results show that dopamine differentially regulates Ca2+ signaling on the order of seconds in two distinct MSN subpopulations.

  8. The effects of emotion regulation on explicit memory depend on strategy and testing method.

    Science.gov (United States)

    Knight, Marisa; Ponzio, Allison

    2013-12-01

    Although previous work has shown that emotion regulation strategies can influence memory, the mechanisms through which different strategies produce different memory outcomes are not well understood. We examined how two cognitive reappraisal strategies with similar elaboration demands but diverging effects on visual attention and emotional arousal influenced explicit memory for emotional stimuli and for the strategies used to evaluate the stimuli. At encoding, participants used reappraisal to increase and decrease the personal relevance of neutral and emotional pictures. In two experiments, recall accuracy was highest for emotional pictures featured on increase trials, intermediate for emotional pictures featured on look (respond naturally) trials, and lowest for emotional pictures featured on decrease trials. This recall pattern emerged after a short delay (15 min) and persisted over a longer delay (48 hr). Memory accuracy for the strategies used to evaluate the pictures showed a different pattern: Strategy memory was better for emotional pictures featured on decrease and increase trials than for pictures featured on look trials. Our findings show that the effects of emotion regulation on memory depend both on the particular strategy engaged and the particular aspect of memory being tested.

  9. A pair of pharyngeal gustatory receptor neurons regulates caffeine-dependent ingestion in Drosophila larvae

    Directory of Open Access Journals (Sweden)

    Jaekyun Choi

    2016-07-01

    Full Text Available The sense of taste is an essential chemosensory modality that enables animals to identify appropriate food sources and control feeding behavior. In particular, the recognition of bitter taste prevents animals from feeding on harmful substances. Feeding is a complex behavior comprised of multiple steps, and food quality is continuously assessed. We here examined the role of pharyngeal gustatory organs in ingestion behavior. As a first step, we constructed a gustatory receptor-to-neuron map of the larval pharyngeal sense organs, and examined corresponding gustatory receptor neuron projections in the larval brain. Out of 22 candidate bitter compounds, we found 14 bitter compounds that elicit inhibition of ingestion in a dose-dependent manner. We provide evidence that certain pharyngeal gustatory receptor neurons are necessary and sufficient for the ingestion response of larvae to caffeine. Additionally, we show that a specific pair of pharyngeal gustatory receptor neurons, DP1, responds to caffeine by calcium imaging. In this study we show that a specific pair of gustatory receptor neurons in the pharyngeal sense organs coordinates caffeine sensing with regulation of behavioral responses such as ingestion. Our results indicate that in Drosophila larvae, the pharyngeal gustatory receptor neurons have a major role in sensing food palatability to regulate ingestion behavior. The pharyngeal sense organs are prime candidates to influence ingestion due to their position in the pharynx, and they may act as first level sensors of ingested food.

  10. Regulation of Serine-Threonine Kinase Akt Activation by NAD+-Dependent Deacetylase SIRT7

    Directory of Open Access Journals (Sweden)

    Jia Yu

    2017-01-01

    Full Text Available The Akt pathway is a central regulator that promotes cell survival in response to extracellular signals. Depletion of SIRT7, an NAD+-dependent deacetylase that is the least-studied sirtuin, is known to significantly increase Akt activity in mice through unknown mechanisms. In this study, we demonstrate that SIRT7 depletion in breast cancer cells results in Akt hyper-phosphorylation and increases cell survival following genotoxic stress. Mechanistically, SIRT7 specifically interacts with and deacetylates FKBP51 at residue lysines 28 and 155 (K28 and K155, resulting in enhanced interactions among FKBP51, Akt, and PHLPP, as well as Akt dephosphorylation. Mutating both lysines to arginines abolishes the effect of SIRT7 on Akt activity through FKBP51 deacetylation. Finally, energy stress strengthens SIRT7-mediated effects on Akt dephosphorylation through FKBP51 and thus sensitizes cancer cells to cytotoxic agents. These results reveal a direct role of SIRT7 in Akt regulation and raise the possibility of using the glucose analog 2-deoxy-D-glucose (2DG as a chemo-sensitizing agent.

  11. Frank-ter Haar syndrome protein Tks4 regulates epidermal growth factor-dependent cell migration.

    Science.gov (United States)

    Bögel, Gábor; Gujdár, Annamária; Geiszt, Miklós; Lányi, Árpád; Fekete, Anna; Sipeki, Szabolcs; Downward, Julian; Buday, László

    2012-09-07

    Mutations in the SH3PXD2B gene coding for the Tks4 protein are responsible for the autosomal recessive Frank-ter Haar syndrome. Tks4, a substrate of Src tyrosine kinase, is implicated in the regulation of podosome formation. Here, we report a novel role for Tks4 in the EGF signaling pathway. In EGF-treated cells, Tks4 is tyrosine-phosphorylated and associated with the activated EGF receptor. This association is not direct but requires the presence of Src tyrosine kinase. In addition, treatment of cells with LY294002, an inhibitor of PI 3-kinase, or mutations of the PX domain reduces tyrosine phosphorylation and membrane translocation of Tks4. Furthermore, a PX domain mutant (R43W) Tks4 carrying a reported point mutation in a Frank-ter Haar syndrome patient showed aberrant intracellular expression and reduced phosphoinositide binding. Finally, silencing of Tks4 was shown to markedly inhibit HeLa cell migration in a Boyden chamber assay in response to EGF or serum. Our results therefore reveal a new function for Tks4 in the regulation of growth factor-dependent cell migration.

  12. ARF6-dependent regulation of P2Y receptor traffic and function in human platelets.

    Science.gov (United States)

    Kanamarlapudi, Venkateswarlu; Owens, Sian E; Saha, Keya; Pope, Robert J; Mundell, Stuart J

    2012-01-01

    Adenosine diphosphate (ADP) is a critical regulator of platelet activation, mediating its actions through two G protein-coupled receptors, the P2Y(1) and P2Y(12) purinoceptors. Recently, we demonstrated that P2Y(1) and P2Y(12) purinoceptor activities are rapidly and reversibly modulated in human platelets, revealing that the underlying mechanism requires receptor internalization and subsequent trafficking as an essential part of this process. In this study we investigated the role of the small GTP-binding protein ADP ribosylation factor 6 (ARF6) in the internalization and function of P2Y(1) and P2Y(12) purinoceptors in human platelets. ARF6 has been implicated in the internalization of a number of GPCRs, although its precise molecular mechanism in this process remains unclear. In this study we show that activation of either P2Y(1) or P2Y(12) purinoceptors can stimulate ARF6 activity. Further blockade of ARF6 function either in cell lines or human platelets blocks P2Y purinoceptor internalization. This blockade of receptor internalization attenuates receptor resensitization. Furthermore, we demonstrate that Nm23-H1, a nucleoside diphosphate (NDP) kinase regulated by ARF6 which facilitates dynamin-dependent fission of coated vesicles during endocytosis, is also required for P2Y purinoceptor internalization. These data describe a novel function of ARF6 in the internalization of P2Y purinoceptors and demonstrate the integral importance of this small GTPase upon platelet ADP receptor function.

  13. ARF6-dependent regulation of P2Y receptor traffic and function in human platelets.

    Directory of Open Access Journals (Sweden)

    Venkateswarlu Kanamarlapudi

    Full Text Available Adenosine diphosphate (ADP is a critical regulator of platelet activation, mediating its actions through two G protein-coupled receptors, the P2Y(1 and P2Y(12 purinoceptors. Recently, we demonstrated that P2Y(1 and P2Y(12 purinoceptor activities are rapidly and reversibly modulated in human platelets, revealing that the underlying mechanism requires receptor internalization and subsequent trafficking as an essential part of this process. In this study we investigated the role of the small GTP-binding protein ADP ribosylation factor 6 (ARF6 in the internalization and function of P2Y(1 and P2Y(12 purinoceptors in human platelets. ARF6 has been implicated in the internalization of a number of GPCRs, although its precise molecular mechanism in this process remains unclear. In this study we show that activation of either P2Y(1 or P2Y(12 purinoceptors can stimulate ARF6 activity. Further blockade of ARF6 function either in cell lines or human platelets blocks P2Y purinoceptor internalization. This blockade of receptor internalization attenuates receptor resensitization. Furthermore, we demonstrate that Nm23-H1, a nucleoside diphosphate (NDP kinase regulated by ARF6 which facilitates dynamin-dependent fission of coated vesicles during endocytosis, is also required for P2Y purinoceptor internalization. These data describe a novel function of ARF6 in the internalization of P2Y purinoceptors and demonstrate the integral importance of this small GTPase upon platelet ADP receptor function.

  14. Cyclic nucleotide dependent dephosphorylation of regulator of G-protein signaling 18 in human platelets.

    LENUS (Irish Health Repository)

    Gegenbauer, Kristina

    2013-11-01

    Regulator of G-protein signaling 18 (RGS18) is a GTPase-activating protein that turns off Gq signaling in platelets. RGS18 is regulated by binding to the adaptor protein 14-3-3 via phosphorylated serine residues S49 and S218 on RGS18. In this study we confirm that thrombin, thromboxane A2, or ADP stimulate the interaction of RGS18 and 14-3-3 by increasing the phosphorylation of S49. Cyclic AMP- and cyclic GMP-dependent kinases (PKA, PKG) inhibit the interaction of RGS18 and 14-3-3 by phosphorylating S216. To understand the effect of S216 phosphorylation we studied the phosphorylation kinetics of S49, S216, and S218 using Phos-tag gels and phosphorylation site-specific antibodies in transfected cells and in platelets. Cyclic nucleotide-induced detachment of 14-3-3 from RGS18 coincides initially with double phosphorylation of S216 and S218. This is followed by dephosphorylation of S49 and S218. Dephosphorylation of S49 and S218 might be mediated by protein phosphatase 1 (PP1) which is linked to RGS18 by the regulatory subunit PPP1R9B (spinophilin). We conclude that PKA and PKG induced S216 phosphorylation triggers the dephosphorylation of the 14-3-3 binding sites of RGS18 in platelets.

  15. Endophilin, Lamellipodin, and Mena cooperate to regulate F-actin-dependent EGF-receptor endocytosis.

    Science.gov (United States)

    Vehlow, Anne; Soong, Daniel; Vizcay-Barrena, Gema; Bodo, Cristian; Law, Ah-Lai; Perera, Upamali; Krause, Matthias

    2013-10-16

    The epidermal growth factor receptor (EGFR) plays an essential role during development and diseases including cancer. Lamellipodin (Lpd) is known to control lamellipodia protrusion by regulating actin filament elongation via Ena/VASP proteins. However, it is unknown whether this mechanism supports endocytosis of the EGFR. Here, we have identified a novel role for Lpd and Mena in clathrin-mediated endocytosis (CME) of the EGFR. We have discovered that endogenous Lpd is in a complex with the EGFR and Lpd and Mena knockdown impairs EGFR endocytosis. Conversely, overexpressing Lpd substantially increases the EGFR uptake in an F-actin-dependent manner, suggesting that F-actin polymerization is limiting for EGFR uptake. Furthermore, we found that Lpd directly interacts with endophilin, a BAR domain containing protein implicated in vesicle fission. We identified a role for endophilin in EGFR endocytosis, which is mediated by Lpd. Consistently, Lpd localizes to clathrin-coated pits (CCPs) just before vesicle scission and regulates vesicle scission. Our findings suggest a novel mechanism in which Lpd mediates EGFR endocytosis via Mena downstream of endophilin.

  16. Down regulation of macrophage IFNGR1 exacerbates systemic L. monocytogenes infection.

    Directory of Open Access Journals (Sweden)

    Emily M Eshleman

    2017-05-01

    Full Text Available Interferons (IFNs target macrophages to regulate inflammation and resistance to microbial infections. The type II IFN (IFNγ acts on a cell surface receptor (IFNGR to promote gene expression that enhance macrophage inflammatory and anti-microbial activity. Type I IFNs can dampen macrophage responsiveness to IFNγ and are associated with increased susceptibility to numerous bacterial infections. The precise mechanisms responsible for these effects remain unclear. Type I IFNs silence macrophage ifngr1 transcription and thus reduce cell surface expression of IFNGR1. To test how these events might impact macrophage activation and host resistance during bacterial infection, we developed transgenic mice that express a functional FLAG-tagged IFNGR1 (fGR1 driven by a macrophage-specific promoter. Macrophages from fGR1 mice expressed physiologic levels of cell surface IFNGR1 at steady state and responded equivalently to WT C57Bl/6 macrophages when treated with IFNγ alone. However, fGR1 macrophages retained cell surface IFNGR1 and showed enhanced responsiveness to IFNγ in the presence of type I IFNs. When fGR1 mice were infected with the bacterium Listeria monocytogenes their resistance was significantly increased, despite normal type I and II IFN production. Enhanced resistance was dependent on IFNγ and associated with increased macrophage activation and antimicrobial function. These results argue that down regulation of myeloid cell IFNGR1 is an important mechanism by which type I IFNs suppress inflammatory and anti-bacterial functions of macrophages.

  17. Regulation of granulocyte colony-stimulating factor receptor-mediated granulocytic differentiation by C-mannosylation.

    Science.gov (United States)

    Otani, Kei; Niwa, Yuki; Suzuki, Takehiro; Sato, Natsumi; Sasazawa, Yukiko; Dohmae, Naoshi; Simizu, Siro

    2018-04-06

    Granulocyte colony-stimulating factor (G-CSF) receptor (G-CSFR) is a type I cytokine receptor which is involved in hematopoietic cell maturation. G-CSFR has three putative C-mannosylation sites at W253, W318, and W446; however, it is not elucidated whether G-CSFR is C-mannosylated or not. In this study, we first demonstrated that G-CSFR was C-mannosylated at only W318. We also revealed that C-mannosylation of G-CSFR affects G-CSF-dependent downstream signaling through changing ligand binding capability but not cell surface localization. Moreover, C-mannosylation of G-CSFR was functional and regulated granulocytic differentiation in myeloid 32D cells. In conclusion, we found that G-CSFR is C-mannosylated at W318 and that this C-mannosylation has role(s) for myeloid cell differentiation through regulating downstream signaling. Copyright © 2018 Elsevier Inc. All rights reserved.

  18. Regulation of tumor necrosis factor gene expression by ionizing radiation in human myeloid leukemia cells and peripheral blood monocytes

    International Nuclear Information System (INIS)

    Sherman, M.L.; Datta, R.; Hallahan, D.E.; Weichselbaum, R.R.; Kufe, D.W.

    1991-01-01

    Previous studies have demonstrated that ionizing radiation induces the expression of certain cytokines, such as TNF alpha/cachectin. However, there is presently no available information regarding the molecular mechanisms responsible for the regulation of cytokine gene expression by ionizing radiation. In this report, we describe the regulation of the TNF gene by ionizing radiation in human myeloid leukemia cells. The increase in TNF transcripts by x rays was both time- and dose-dependent as determined by Northern blot analysis. Similar findings were obtained in human peripheral blood monocytes. Transcriptional run-on analyses have demonstrated that ionizing radiation stimulates the rate of TNF gene transcription. Furthermore, induction of TNF mRNA was increased in the absence of protein synthesis. In contrast, ionizing radiation had little effect on the half-life of TNF transcripts. These findings indicate that the increase in TNF mRNA observed after irradiation is regulated by transcriptional mechanisms and suggest that production of this cytokine by myeloid cells may play a role in the pathophysiologic effects of ionizing radiation

  19. Density regulation in Northeast Atlantic fish populations: Density dependence is stronger in recruitment than in somatic growth.

    Science.gov (United States)

    Zimmermann, Fabian; Ricard, Daniel; Heino, Mikko

    2018-05-01

    Population regulation is a central concept in ecology, yet in many cases its presence and the underlying mechanisms are difficult to demonstrate. The current paradigm maintains that marine fish populations are predominantly regulated by density-dependent recruitment. While it is known that density-dependent somatic growth can be present too, its general importance remains unknown and most practical applications neglect it. This study aimed to close this gap by for the first time quantifying and comparing density dependence in growth and recruitment over a large set of fish populations. We fitted density-dependent models to time-series data on population size, recruitment and age-specific weight from commercially exploited fish populations in the Northeast Atlantic Ocean and the Baltic Sea. Data were standardized to enable a direct comparison within and among populations, and estimated parameters were used to quantify the impact of density regulation on population biomass. Statistically significant density dependence in recruitment was detected in a large proportion of populations (70%), whereas for density dependence in somatic growth the prevalence of density dependence depended heavily on the method (26% and 69%). Despite age-dependent variability, the density dependence in recruitment was consistently stronger among age groups and between alternative approaches that use weight-at-age or weight increments to assess growth. Estimates of density-dependent reduction in biomass underlined these results: 97% of populations with statistically significant parameters for growth and recruitment showed a larger impact of density-dependent recruitment on population biomass. The results reaffirm the importance of density-dependent recruitment in marine fishes, yet they also show that density dependence in somatic growth is not uncommon. Furthermore, the results are important from an applied perspective because density dependence in somatic growth affects productivity and

  20. Mitochondrial Sirt3 supports cell proliferation by regulating glutamine-dependent oxidation in renal cell carcinoma

    International Nuclear Information System (INIS)

    Choi, Jieun; Koh, Eunjin; Lee, Yu Shin; Lee, Hyun-Woo; Kang, Hyeok Gu; Yoon, Young Eun; Han, Woong Kyu; Choi, Kyung Hwa; Kim, Kyung-Sup

    2016-01-01

    Clear cell renal carcinoma (RCC), the most common malignancy arising in the adult kidney, exhibits increased aerobic glycolysis and low mitochondrial respiration due to von Hippel-Lindau gene defects and constitutive hypoxia-inducible factor-α expression. Sirt3 is a major mitochondrial deacetylase that mediates various types of energy metabolism. However, the role of Sirt3 as a tumor suppressor or oncogene in cancer depends on cell types. We show increased Sirt3 expression in the mitochondrial fraction of human RCC tissues. Sirt3 depletion by lentiviral short-hairpin RNA, as well as the stable expression of the inactive mutant of Sirt3, inhibited cell proliferation and tumor growth in xenograft nude mice, respectively. Furthermore, mitochondrial pyruvate, which was used for oxidation in RCC, might be derived from glutamine, but not from glucose and cytosolic pyruvate, due to depletion of mitochondrial pyruvate carrier and the relatively high expression of malic enzyme 2. Depletion of Sirt3 suppressed glutamate dehydrogenase activity, leading to impaired mitochondrial oxygen consumption. Our findings suggest that Sirt3 plays a tumor-progressive role in human RCC by regulating glutamine-derived mitochondrial respiration, particularly in cells where mitochondrial usage of cytosolic pyruvate is severely compromised. -- Highlights: •Sirt3 is required for the maintenance of RCC cell proliferation. •Mitochondrial usage of cytosolic pyruvate is severely compromised in RCC. •Sirt3 supports glutamine-dependent oxidation in RCC.

  1. CREB Regulates Experience-Dependent Spine Formation and Enlargement in Mouse Barrel Cortex

    Directory of Open Access Journals (Sweden)

    Annabella Pignataro

    2015-01-01

    Full Text Available Experience modifies synaptic connectivity through processes that involve dendritic spine rearrangements in neuronal circuits. Although cAMP response element binding protein (CREB has a key function in spines changes, its role in activity-dependent rearrangements in brain regions of rodents interacting with the surrounding environment has received little attention so far. Here we studied the effects of vibrissae trimming, a widely used model of sensory deprivation-induced cortical plasticity, on processes associated with dendritic spine rearrangements in the barrel cortex of a transgenic mouse model of CREB downregulation (mCREB mice. We found that sensory deprivation through prolonged whisker trimming leads to an increased number of thin spines in the layer V of related barrel cortex (Contra in wild type but not mCREB mice. In the barrel field controlling spared whiskers (Ipsi, the same trimming protocol results in a CREB-dependent enlargement of dendritic spines. Last, we demonstrated that CREB regulates structural rearrangements of synapses that associate with dynamic changes of dendritic spines. Our findings suggest that CREB plays a key role in dendritic spine dynamics and synaptic circuits rearrangements that account for new brain connectivity in response to changes in the environment.

  2. Gibberellic acid and cGMP-dependent transcriptional regulation in arabidopsis thaliana

    KAUST Repository

    Bastian, René

    2010-03-01

    An ever increasing amount of transcriptomic data and analysis tools provide novel insight into complex responses of biological systems. Given these resources we have undertaken to review aspects of transcriptional regulation in response to the plant hormone gibberellic acid (GA) and its second messenger guanosine 3\\',5\\'-cyclic monophosphate (cGMP) in Arabidopsis thaliana, both wild type and selected mutants. Evidence suggests enrichment of GA-responsive (GARE) elements in promoters of genes that are transcriptionally upregulated in response to cGMP but downregulated in a GA insensitive mutant (ga1-3). In contrast, in the genes upregulated in the mutant, no enrichment in the GARE is observed suggesting that GARE motifs are diagnostic for GA-induced and cGMP-dependent transcriptional upregulation. Further, we review how expression studies of GA-dependent transcription factors and transcriptional networks based on common promoter signatures derived from ab initio analyses can contribute to our understanding of plant responses at the systems level. © 2010 Landes Bioscience.

  3. Vitamin B12–dependent taurine synthesis regulates growth and bone mass

    Science.gov (United States)

    Roman-Garcia, Pablo; Quiros-Gonzalez, Isabel; Mottram, Lynda; Lieben, Liesbet; Sharan, Kunal; Wangwiwatsin, Arporn; Tubio, Jose; Lewis, Kirsty; Wilkinson, Debbie; Santhanam, Balaji; Sarper, Nazan; Clare, Simon; Vassiliou, George S.; Velagapudi, Vidya R.; Dougan, Gordon; Yadav, Vijay K.

    2014-01-01

    Both maternal and offspring-derived factors contribute to lifelong growth and bone mass accrual, although the specific role of maternal deficiencies in the growth and bone mass of offspring is poorly understood. In the present study, we have shown that vitamin B12 (B12) deficiency in a murine genetic model results in severe postweaning growth retardation and osteoporosis, and the severity and time of onset of this phenotype in the offspring depends on the maternal genotype. Using integrated physiological and metabolomic analysis, we determined that B12 deficiency in the offspring decreases liver taurine production and associates with abrogation of a growth hormone/insulin-like growth factor 1 (GH/IGF1) axis. Taurine increased GH-dependent IGF1 synthesis in the liver, which subsequently enhanced osteoblast function, and in B12-deficient offspring, oral administration of taurine rescued their growth retardation and osteoporosis phenotypes. These results identify B12 as an essential vitamin that positively regulates postweaning growth and bone formation through taurine synthesis and suggests potential therapies to increase bone mass. PMID:24911144

  4. Mitochondrial Sirt3 supports cell proliferation by regulating glutamine-dependent oxidation in renal cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jieun; Koh, Eunjin; Lee, Yu Shin; Lee, Hyun-Woo; Kang, Hyeok Gu [Department of Biochemistry and Molecular Biology, Brain Korea 21 PLUS Project for Medical Sciences, Institute of Genetic Science, Integrated Genomic Research Center for Metabolic Regulation, Yonsei University College of Medicine, Seoul 120-752 (Korea, Republic of); Yoon, Young Eun; Han, Woong Kyu [Department of Urology, Urological Science Institute, Yonsei University College of Medicine, Seoul 120-752 (Korea, Republic of); Choi, Kyung Hwa [Department of Urology, CHA Bundang Medical Center, CHA University, Seongnam 463-712 (Korea, Republic of); Kim, Kyung-Sup, E-mail: KYUNGSUP59@yuhs.ac [Department of Biochemistry and Molecular Biology, Brain Korea 21 PLUS Project for Medical Sciences, Institute of Genetic Science, Integrated Genomic Research Center for Metabolic Regulation, Yonsei University College of Medicine, Seoul 120-752 (Korea, Republic of)

    2016-06-03

    Clear cell renal carcinoma (RCC), the most common malignancy arising in the adult kidney, exhibits increased aerobic glycolysis and low mitochondrial respiration due to von Hippel-Lindau gene defects and constitutive hypoxia-inducible factor-α expression. Sirt3 is a major mitochondrial deacetylase that mediates various types of energy metabolism. However, the role of Sirt3 as a tumor suppressor or oncogene in cancer depends on cell types. We show increased Sirt3 expression in the mitochondrial fraction of human RCC tissues. Sirt3 depletion by lentiviral short-hairpin RNA, as well as the stable expression of the inactive mutant of Sirt3, inhibited cell proliferation and tumor growth in xenograft nude mice, respectively. Furthermore, mitochondrial pyruvate, which was used for oxidation in RCC, might be derived from glutamine, but not from glucose and cytosolic pyruvate, due to depletion of mitochondrial pyruvate carrier and the relatively high expression of malic enzyme 2. Depletion of Sirt3 suppressed glutamate dehydrogenase activity, leading to impaired mitochondrial oxygen consumption. Our findings suggest that Sirt3 plays a tumor-progressive role in human RCC by regulating glutamine-derived mitochondrial respiration, particularly in cells where mitochondrial usage of cytosolic pyruvate is severely compromised. -- Highlights: •Sirt3 is required for the maintenance of RCC cell proliferation. •Mitochondrial usage of cytosolic pyruvate is severely compromised in RCC. •Sirt3 supports glutamine-dependent oxidation in RCC.

  5. Abscisic acid-dependent multisite phosphorylation regulates the activity of a transcription activator AREB1.

    Science.gov (United States)

    Furihata, Takashi; Maruyama, Kyonoshin; Fujita, Yasunari; Umezawa, Taishi; Yoshida, Riichiro; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

    2006-02-07

    bZIP-type transcription factors AREBs/ABFs bind an abscisic acid (ABA)-responsive cis-acting element named ABRE and transactivate downstream gene expression in Arabidopsis. Because AREB1 overexpression could not induce downstream gene expression, activation of AREB1 requires ABA-dependent posttranscriptional modification. We confirmed that ABA activated 42-kDa kinase activity, which, in turn, phosphorylated Ser/Thr residues of R-X-X-S/T sites in the conserved regions of AREB1. Amino acid substitutions of R-X-X-S/T sites to Ala suppressed transactivation activity, and multiple substitution of these sites resulted in almost complete suppression of transactivation activity in transient assays. In contrast, substitution of the Ser/Thr residues to Asp resulted in high transactivation activity without exogenous ABA application. A phosphorylated, transcriptionally active form was achieved by substitution of Ser/Thr in all conserved R-X-X-S/T sites to Asp. Transgenic plants overexpressing the phosphorylated active form of AREB1 expressed many ABA-inducible genes, such as RD29B, without ABA treatment. These results indicate that the ABA-dependent multisite phosphorylation of AREB1 regulates its own activation in plants.

  6. HIC1 links retinoic acid signalling to group 3 innate lymphoid cell-dependent regulation of intestinal immunity and homeostasis

    Science.gov (United States)

    Antignano, Frann; Korinek, Vladimir; Underhill, T. Michael

    2018-01-01

    The intestinal immune system must be able to respond to a wide variety of infectious organisms while maintaining tolerance to non-pathogenic microbes and food antigens. The Vitamin A metabolite all-trans-retinoic acid (atRA) has been implicated in the regulation of this balance, partially by regulating innate lymphoid cell (ILC) responses in the intestine. However, the molecular mechanisms of atRA-dependent intestinal immunity and homeostasis remain elusive. Here we define a role for the transcriptional repressor Hypermethylated in cancer 1 (HIC1, ZBTB29) in the regulation of ILC responses in the intestine. Intestinal ILCs express HIC1 in a vitamin A-dependent manner. In the absence of HIC1, group 3 ILCs (ILC3s) that produce IL-22 are lost, resulting in increased susceptibility to infection with the bacterial pathogen Citrobacter rodentium. Thus, atRA-dependent expression of HIC1 in ILC3s regulates intestinal homeostasis and protective immunity. PMID:29470558

  7. CD40 dependent exacerbation of immune mediated hepatitis by hepatic CD11b+ Gr-1+ myeloid derived suppressor cells in tumor bearing mice

    Science.gov (United States)

    Kapanadze, Tamar; Medina-Echeverz, José; Gamrekelashvili, Jaba; Weiss, Jonathan M.; Wiltrout, Robert H.; Kapoor, Veena; Hawk, Nga; Terabe, Masaki; Berzofsky, Jay A.; Manns, Michael P.; Wang, Ena; Marincola, Francesco M.; Korangy, Firouzeh; Greten, Tim F.

    2015-01-01

    Immunosuppressive CD11b+Gr-1+ myeloid-derived suppressor cells (MDSC) accumulate in the livers of tumor-bearing mice. We studied hepatic MDSC in two murine models of immune mediated hepatitis. Unexpectedly, treatment of tumor bearing mice with Concanavalin A or α-Galactosylceramide resulted in increased ALT and AST serum levels in comparison to tumor free mice. Adoptive transfer of hepatic MDSC into naïve mice exacerbated Concanavalin A induced liver damage. Hepatic CD11b+Gr-1+ cells revealed a polarized pro-inflammatory gene signature after Concanavalin A treatment. An interferon gamma- dependent up-regulation of CD40 on hepatic CD11b+Gr-1+ cells along with an up-regulation of CD80, CD86, and CD1d after Concanavalin A treatment was observed. Concanavalin A treatment resulted in a loss of suppressor function by tumor-induced CD11b+Gr-1+ MDSC as well as enhanced reactive oxygen species-mediated hepatotoxicity. CD40 knockdown in hepatic MDSC led to increased arginase activity upon Concanavalin A treatment and lower ALT/AST serum levels. Finally, blockade of arginase activity in Cd40−/− tumor-induced myeloid cells resulted in exacerbation of hepatitis and increased reactive oxygen species production in vivo. Our findings indicate that in a setting of acute hepatitis, tumor-induced hepatic MDSC act as pro-inflammatory immune effector cells capable of killing hepatocytes in a CD40-dependent manner. PMID:25616156

  8. TLR4 has a TP53-dependent dual role in regulating breast cancer cell growth.

    Science.gov (United States)

    Haricharan, Svasti; Brown, Powel

    2015-06-23

    Breast cancer is a leading cause of cancer-related death, and it is important to understand pathways that drive the disease to devise effective therapeutic strategies. Our results show that Toll-like receptor 4 (TLR4) drives breast cancer cell growth differentially based on the presence of TP53, a tumor suppressor. TP53 is mutationally inactivated in most types of cancer and is mutated in 30-50% of diagnosed breast tumors. We demonstrate that TLR4 activation inhibits growth of TP53 wild-type cells, but promotes growth of TP53 mutant breast cancer cells by regulating proliferation. This differential effect is mediated by changes in tumor cell cytokine secretion. Whereas TLR4 activation in TP53 mutant breast cancer cells increases secretion of progrowth cytokines, TLR4 activation in TP53 wild-type breast cancer cells increases type I IFN (IFN-γ) secretion, which is both necessary and sufficient for mediating TLR4-induced growth inhibition. This study identifies a novel dichotomous role for TLR4 as a growth regulator and a modulator of tumor microenvironment in breast tumors. These results have translational relevance, demonstrating that TP53 mutant breast tumor growth can be suppressed by pharmacologic TLR4 inhibition, whereas TLR4 inhibitors may in fact promote growth of TP53 wild-type tumors. Furthermore, using data generated by The Cancer Genome Atlas consortium, we demonstrate that the effect of TP53 mutational status on TLR4 activity may extend to ovarian, colon, and lung cancers, among others, suggesting that the viability of TLR4 as a therapeutic target depends on TP53 status in many different tumor types.

  9. Control of the neurovascular coupling by nitric oxide-dependent regulation of astrocytic Ca2+ signaling

    Directory of Open Access Journals (Sweden)

    Manuel Francisco Muñoz

    2015-03-01

    Full Text Available Neuronal activity must be tightly coordinated with blood flow to keep proper brain function, which is achieved by a mechanism known as neurovascular coupling. Then, an increase in synaptic activity leads to a dilation of local parenchymal arterioles that matches the enhanced metabolic demand. Neurovascular coupling is orchestrated by astrocytes. These glial cells are located between neurons and the microvasculature, with the astrocytic endfeet ensheathing the vessels, which allows fine intercellular communication. The neurotransmitters released during neuronal activity reach astrocytic receptors and trigger a Ca2+ signaling that propagates to the endfeet, activating the release of vasoactive factors and arteriolar dilation. The astrocyte Ca2+ signaling is coordinated by gap junction channels and hemichannels formed by connexins (Cx43 and Cx30 and channels formed by pannexins (Panx-1. The neuronal activity-initiated Ca2+ waves are propagated among neighboring astrocytes directly via gap junctions or through ATP release via connexin hemichannels or pannexin channels. In addition, Ca2+ entry via connexin hemichannels or pannexin channels may participate in the regulation of the astrocyte signaling-mediated neurovascular coupling. Interestingly, nitric oxide (NO can activate connexin hemichannel by S-nitrosylation and the Ca2+-dependent NO-synthesizing enzymes endothelial NO synthase (eNOS and neuronal NOS (nNOS are expressed in astrocytes. Therefore, the astrocytic Ca2+ signaling triggered in neurovascular coupling may activate NO production, which, in turn, may lead to Ca2+ influx through hemichannel activation. Furthermore, NO release from the hemichannels located at astrocytic endfeet may contribute to the vasodilation of parenchymal arterioles. In this review, we discuss the mechanisms involved in the regulation of the astrocytic Ca2+ signaling that mediates neurovascular coupling, with a special emphasis in the possible participation of NO in

  10. Thioredoxin and NADPH-Dependent Thioredoxin Reductase C Regulation of Tetrapyrrole Biosynthesis.

    Science.gov (United States)

    Da, Qingen; Wang, Peng; Wang, Menglong; Sun, Ting; Jin, Honglei; Liu, Bing; Wang, Jinfa; Grimm, Bernhard; Wang, Hong-Bin

    2017-10-01

    In chloroplasts, thioredoxin (TRX) isoforms and NADPH-dependent thioredoxin reductase C (NTRC) act as redox regulatory factors involved in multiple plastid biogenesis and metabolic processes. To date, less is known about the functional coordination between TRXs and NTRC in chlorophyll biosynthesis. In this study, we aimed to explore the potential functions of TRX m and NTRC in the regulation of the tetrapyrrole biosynthesis (TBS) pathway. Silencing of three genes, TRX m1 , TRX m2 , and TRX m4 ( TRX ms ), led to pale-green leaves, a significantly reduced 5-aminolevulinic acid (ALA)-synthesizing capacity, and reduced accumulation of chlorophyll and its metabolic intermediates in Arabidopsis ( Arabidopsis thaliana ). The contents of ALA dehydratase, protoporphyrinogen IX oxidase, the I subunit of Mg-chelatase, Mg-protoporphyrin IX methyltransferase (CHLM), and NADPH-protochlorophyllide oxidoreductase were decreased in triple TRX m- silenced seedlings compared with the wild type, although the transcript levels of the corresponding genes were not altered significantly. Protein-protein interaction analyses revealed a physical interaction between the TRX m isoforms and CHLM. 4-Acetoamido-4-maleimidylstilbene-2,2-disulfonate labeling showed the regulatory impact of TRX ms on the CHLM redox status. Since CHLM also is regulated by NTRC (Richter et al., 2013), we assessed the concurrent functions of TRX m and NTRC in the control of CHLM. Combined deficiencies of three TRX m isoforms and NTRC led to a cumulative decrease in leaf pigmentation, TBS intermediate contents, ALA synthesis rate, and CHLM activity. We discuss the coordinated roles of TRX m and NTRC in the redox control of CHLM stability with its corollary activity in the TBS pathway. © 2017 American Society of Plant Biologists. All Rights Reserved.

  11. Down-regulation of voltage-dependent sodium channels initiated by sodium influx in developing neurons

    International Nuclear Information System (INIS)

    Dargent, B.; Couraud, F.

    1990-01-01

    To address the issue of whether regulatory feedback exists between the electrical activity of a neuron and ion-channel density, the authors investigated the effect of Na + -channel activators (scorpion α toxin, batrachotoxin, and veratridine) on the density of Na + channels in fetal rat brain neurons in vitro. A partial but rapid (t 1/2 , 15 min) disappearance of surface Na + channels was observed as measured by a decrease in the specific binding of [ 3 H]saxitoxin and 125 I-labeled scorpion β toxin and a decrease in specific 22 Na + uptake. Moreover, the increase in the number of Na + channels that normally occurs during neuronal maturation in vitro was inhibited by chronic channel activator treatment. The induced disappearance of Na + channels was abolished by tetrodotoxin, was found to be dependent on the external Na + concentration, and was prevented when either choline (a nonpermeant ion) or Li + (a permeant ion) was substituted for Na + . Amphotericin B, a Na + ionophore, and monensin were able to mimick the effect of Na + -channel activators, while a KCl depolarization failed to do this. This feedback regulation seems to be a neuronal property since Na + -channel density in cultured astrocytes was not affected by channel activator treatment or by amphotericin B. The present evidence suggests that an increase in intracellular Na + concentration, whether elicited by Na + -channel activators or mediated by a Na + ionophore, can induce a decrease in surface Na + channels and therefore is involved in down-regulation of Na + -channel density in fetal rat brain neurons in vitro

  12. Protein kinase activity of phosphoinositide 3-kinase regulates cytokine-dependent cell survival.

    Directory of Open Access Journals (Sweden)

    Daniel Thomas

    Full Text Available The dual specificity protein/lipid kinase, phosphoinositide 3-kinase (PI3K, promotes growth factor-mediated cell survival and is frequently deregulated in cancer. However, in contrast to canonical lipid-kinase functions, the role of PI3K protein kinase activity in regulating cell survival is unknown. We have employed a novel approach to purify and pharmacologically profile protein kinases from primary human acute myeloid leukemia (AML cells that phosphorylate serine residues in the cytoplasmic portion of cytokine receptors to promote hemopoietic cell survival. We have isolated a kinase activity that is able to directly phosphorylate Ser585 in the cytoplasmic domain of the interleukin 3 (IL-3 and granulocyte macrophage colony stimulating factor (GM-CSF receptors and shown it to be PI3K. Physiological concentrations of cytokine in the picomolar range were sufficient for activating the protein kinase activity of PI3K leading to Ser585 phosphorylation and hemopoietic cell survival but did not activate PI3K lipid kinase signaling or promote proliferation. Blockade of PI3K lipid signaling by expression of the pleckstrin homology of Akt1 had no significant impact on the ability of picomolar concentrations of cytokine to promote hemopoietic cell survival. Furthermore, inducible expression of a mutant form of PI3K that is defective in lipid kinase activity but retains protein kinase activity was able to promote Ser585 phosphorylation and hemopoietic cell survival in the absence of cytokine. Blockade of p110α by RNA interference or multiple independent PI3K inhibitors not only blocked Ser585 phosphorylation in cytokine-dependent cells and primary human AML blasts, but also resulted in a block in survival signaling and cell death. Our findings demonstrate a new role for the protein kinase activity of PI3K in phosphorylating the cytoplasmic tail of the GM-CSF and IL-3 receptors to selectively regulate cell survival highlighting the importance of targeting

  13. Cyclin dependent kinase 5 regulates endocytosis in nerve terminals via dynamin I phosphorylation

    International Nuclear Information System (INIS)

    Tan, T.C.; Hansra, G.; Calova, V.; Cousin, M.; Robinson, P.J.

    2002-01-01

    Full text: Synaptic vesicle endocytosis (SVE) in nerve terminals is essential for normal synaptic transmission and for memory retrieval. Dynamin I is a 96kDa nerve terminal phosphoprotein necessary for synaptic vesicle endocytosis in the nerve terminal. Dynamin I is dephosphorylated and rephosphorylated in a cyclical fashion with nerve terminal depolarisation and repolarisation. A number of kinases phosphorylate dynamin I in vitro including PKC, MAP kinase and cdc2. PKC phosphorylates dynamin in the proline rich domain on Ser 795 and is also thought to be the in vivo kinase for dynamin I. Another candidate is the neuron specific kinase cdk5, crucial for CNS development. The aim of this study is to identify the kinase which phosphorylates dynamin I in intact nerve terminals. Here we show that cyclin-dependent kinase 5 (cdk5) phosphorylates dynamin I in the proline-rich tail on Ser-774 or Ser-778. The phosphorylation of these sites but not Ser-795 also occurred in intact nerve terminals suggesting that cdk5 is the physiologically relevant enzyme for dynamin I. Synaptosomes prepared from rat brains (after cervical dislocations) and labelled with 32 Pi, were incubated with 100 M roscovitine (a selective inhibitor of cdks), 10 M Ro 31-8220 (a selective PKC inhibitor) and 100 M PD 98059 (a MEK kinase inhibitor). Dynamin rephosphorylation during repolarisation was reduced in synaptosomes treated with roscovitine and Ro 38-8220 but not in synaptosomes treated with PD 98059. Fluorimetric experiments on intact synaptosomes utilising FM-210 (a fluorescent dye) indicate that endocytosis was reduced in synaptosomes treated with 100 M roscovitine. Our results suggest that dynamin phosphorylation in intact nerve terminals may not be regulated by PKC or MAP kinase and that dynamin phosphorylation by cdk5 may regulate endocytosis. Copyright (2002) Australian Neuroscience Society

  14. Prolyl hydroxylase-1 regulates hepatocyte apoptosis in an NF-κB-dependent manner

    Energy Technology Data Exchange (ETDEWEB)

    Fitzpatrick, Susan F.; Fábián, Zsolt; Schaible, Bettina; Lenihan, Colin R.; Schwarzl, Thomas [School of Medicine and Medical Science, The Conway Institute, University College Dublin, Belfield, Dublin 4 Ireland (Ireland); Rodriguez, Javier [Systems Biology Ireland, University College Dublin, Dublin 4 (Ireland); Zheng, Xingnan; Li, Zongwei [Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC (United States); Tambuwala, Murtaza M. [School of Pharmacy and Pharmaceutical Sciences, Ulster University, Coleraine, BT52 1SA, Northern Ireland (United Kingdom); Higgins, Desmond G.; O' Meara, Yvonne [School of Medicine and Medical Science, The Conway Institute, University College Dublin, Belfield, Dublin 4 Ireland (Ireland); Slattery, Craig [School of Biomolecular and Biomedical Science, The Conway Institute, University College Dublin, Belfield, Dublin 4 Ireland (Ireland); Manresa, Mario C. [School of Medicine and Medical Science, The Conway Institute, University College Dublin, Belfield, Dublin 4 Ireland (Ireland); Fraisl, Peter; Bruning, Ulrike [Laboratory of Angiogenesis and Vascular Metabolism, Department of Oncology, University of Leuven, Vesalius Research Center, VIB, B-3000 (Belgium); Baes, Myriam [Laboratory for Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven (Belgium); Carmeliet, Peter; Doherty, Glen [Laboratory of Angiogenesis and Vascular Metabolism, Department of Oncology, University of Leuven, Vesalius Research Center, VIB, B-3000 (Belgium); Kriegsheim, Alex von [Systems Biology Ireland, University College Dublin, Dublin 4 (Ireland); Cummins, Eoin P. [School of Medicine and Medical Science, The Conway Institute, University College Dublin, Belfield, Dublin 4 Ireland (Ireland); and others

    2016-06-03

    Hepatocyte death is an important contributing factor in a number of diseases of the liver. PHD1 confers hypoxic sensitivity upon transcription factors including the hypoxia inducible factor (HIF) and nuclear factor-kappaB (NF-κB). Reduced PHD1 activity is linked to decreased apoptosis. Here, we investigated the underlying mechanism(s) in hepatocytes. Basal NF-κB activity was elevated in PHD1{sup −/−} hepatocytes compared to wild type controls. ChIP-seq analysis confirmed enhanced binding of NF-κB to chromatin in regions proximal to the promoters of genes involved in the regulation of apoptosis. Inhibition of NF-κB (but not knock-out of HIF-1 or HIF-2) reversed the anti-apoptotic effects of pharmacologic hydroxylase inhibition. We hypothesize that PHD1 inhibition leads to altered expression of NF-κB-dependent genes resulting in reduced apoptosis. This study provides new information relating to the possible mechanism of therapeutic action of hydroxylase inhibitors that has been reported in pre-clinical models of intestinal and hepatic disease. -- Highlights: •Genetic ablation of PHD1 upregulates NF-kappaB (NF-κB) in hepatocytes. •Activation of NF-κB leads to differential DNA-binding of p50/p65 and results in differential regulation of apoptotic genes. •We identified proline 191 in the beta subunit of the I-kappaB kinase as a target for PHD1-mediated hydroxylation. •Blockade of prolyl-4-hydroxylases has been found cytoprotective in liver cells.

  15. Activity-dependent astrocyte swelling is mediated by pH-regulating mechanisms.

    Science.gov (United States)

    Larsen, Brian Roland; MacAulay, Nanna

    2017-10-01

    During neuronal activity in the mammalian brain, the K + released into the synaptic space is initially buffered by the astrocytic compartment. In parallel, the extracellular space (ECS) shrinks, presumably due to astrocytic cell swelling. With the Na + /K + /2Cl - cotransporter and the Kir4.1/AQP4 complex not required for the astrocytic cell swelling in the hippocampus, the molecular mechanisms underlying the activity-dependent ECS shrinkage have remained unresolved. To identify these molecular mechanisms, we employed ion-sensitive microelectrodes to measure changes in ECS, [K + ] o and [H + ] o /pH o during electrical stimulation of rat hippocampal slices. Transporters and receptors responding directly to the K + and glutamate released into the extracellular space (the K + /Cl - cotransporter, KCC, glutamate transporters and G protein-coupled receptors) did not modulate the extracellular space dynamics. The HCO3--transporting mechanism, which in astrocytes mainly constitutes the electrogenic Na + / HCO3- cotransporter 1 (NBCe1), is activated by the K + -mediated depolarization of the astrocytic membrane. Inhibition of this transporter reduced the ECS shrinkage by ∼25% without affecting the K + transients, pointing to NBCe1 as a key contributor to the stimulus-induced astrocytic cell swelling. Inhibition of the monocarboxylate cotransporters (MCT), like-wise, reduced the ECS shrinkage by ∼25% without compromising the K + transients. Isosmotic reduction of extracellular Cl - revealed a requirement for this ion in parts of the ECS shrinkage. Taken together, the stimulus-evoked astrocytic cell swelling does not appear to occur as a direct effect of the K + clearance, as earlier proposed, but partly via the pH-regulating transport mechanisms activated by the K + -induced astrocytic depolarization and the activity-dependent metabolism. © 2017 Wiley Periodicals, Inc.

  16. Use of plasma C-reactive protein, procalcitonin, neutrophils,macrophage migration inhibitory factor, soluble urokinase-type plasminogen activator receptor, and soluble triggering receptor expressed on myeloid cells-1 in combination to diagnose infections: a prospective study

    DEFF Research Database (Denmark)

    Kofoed, Kristian; Andersen, Ove; Kronborg, Gitte

    2007-01-01

    the diagnostic characteristics of novel and routinely used biomarkers of sepsis alone and in combination. Methods: This prospective cohort study included patients with systemic inflammatory response syndrome who were suspected of having community-acquired infections. It was conducted in a medical emergency...... department and department of infectious diseases at a university hospital. A multiplex immunoassay measuring soluble urokinase-type plasminogen activator (suPAR) and soluble triggering receptor expressed on myeloid cells (sTREM)-1 and macrophage migration inhibitory factor (MIF) was used in parallel...... with standard measurements of C-reactive protein (CRP), procalcitonin (PCT), and neutrophils. Two composite markers were constructed – one including a linear combination of the three best performing markers and another including all six – and the area under the receiver operating characteristic curve (AUC...

  17. Mechanical stress regulates insulin sensitivity through integrin-dependent control of insulin receptor localization.

    Science.gov (United States)

    Kim, Jung; Bilder, David; Neufeld, Thomas P

    2018-01-15

    Insulin resistance, the failure to activate insulin signaling in the presence of ligand, leads to metabolic diseases, including type 2 diabetes. Physical activity and mechanical stress have been shown to protect against insulin resistance, but the molecular mechanisms remain unclear. Here, we address this relationship in the Drosophila larval fat body, an insulin-sensitive organ analogous to vertebrate adipose tissue and livers. We found that insulin signaling in Drosophila fat body cells is abolished in the absence of physical activity and mechanical stress even when excess insulin is present. Physical movement is required for insulin sensitivity in both intact larvae and fat bodies cultured ex vivo. Interestingly, the insulin receptor and other downstream components are recruited to the plasma membrane in response to mechanical stress, and this membrane localization is rapidly lost upon disruption of larval or tissue movement. Sensing of mechanical stimuli is mediated in part by integrins, whose activation is necessary and sufficient for mechanical stress-dependent insulin signaling. Insulin resistance develops naturally during the transition from the active larval stage to the immotile pupal stage, suggesting that regulation of insulin sensitivity by mechanical stress may help coordinate developmental programming with metabolism. © 2018 Kim et al.; Published by Cold Spring Harbor Laboratory Press.

  18. Evidence of a Redox-Dependent Regulation of Immune Responses to Exercise-Induced Inflammation

    Directory of Open Access Journals (Sweden)

    Alexandra Sakelliou

    2016-01-01

    Full Text Available We used thiol-based antioxidant supplementation (n-acetylcysteine, NAC to determine whether immune mobilisation following skeletal muscle microtrauma induced by exercise is redox-sensitive in healthy humans. According to a two-trial, double-blind, crossover, repeated measures design, 10 young men received either placebo or NAC (20 mg/kg/day immediately after a muscle-damaging exercise protocol (300 eccentric contractions and for eight consecutive days. Blood sampling and performance assessments were performed before exercise, after exercise, and daily throughout recovery. NAC reduced the decline of reduced glutathione in erythrocytes and the increase of plasma protein carbonyls, serum TAC and erythrocyte oxidized glutathione, and TBARS and catalase activity during recovery thereby altering postexercise redox status. The rise of muscle damage and inflammatory markers (muscle strength, creatine kinase activity, CRP, proinflammatory cytokines, and adhesion molecules was less pronounced in NAC during the first phase of recovery. The rise of leukocyte and neutrophil count was decreased by NAC after exercise. Results on immune cell subpopulations obtained by flow cytometry indicated that NAC ingestion reduced the exercise-induced rise of total macrophages, HLA+ macrophages, and 11B+ macrophages and abolished the exercise-induced upregulation of B lymphocytes. Natural killer cells declined only in PLA immediately after exercise. These results indicate that thiol-based antioxidant supplementation blunts immune cell mobilisation in response to exercise-induced inflammation suggesting that leukocyte mobilization may be under redox-dependent regulation.

  19. Berberine regulates neurite outgrowth through AMPK-dependent pathways by lowering energy status

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jiaqi; Cao, Yuanzhao; Cheng, Kuoyuan; Xu, Bo; Wang, Tianchang; Yang, Qi; Yang, Qin [State Key Laboratory of Natural and Biomimetic Drugs, Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing (China); Feng, Xudong, E-mail: xudong.feng@childrens.harvard.edu [Department of Medicine, Children' s Hospital Boston, Harvard Medical School, 300 Longwood Ave, Boston, MA 02115 (United States); Xia, Qing, E-mail: xqing@hsc.pku.edu.cn [State Key Laboratory of Natural and Biomimetic Drugs, Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing (China)

    2015-06-10

    As a widely used anti-bacterial agent and a metabolic inhibitor as well as AMP-activated protein kinase (AMPK) activator, berberine (BBR) has been shown to cross the blood–brain barrier. Its efficacy has been investigated in various disease models of the central nervous system. Neurite outgrowth is critical for nervous system development and is a highly energy-dependent process regulated by AMPK-related pathways. In the present study, we aimed to investigate the effects of BBR on AMPK activation and neurite outgrowth in neurons. The neurite outgrowth of primary rat cortical neurons at different stages of polarization was monitored after exposure of BBR. Intracellular energy level, AMPK activation and polarity-related pathways were also inspected. The results showed that BBR suppressed neurite outgrowth and affected cytoskeleton stability in the early stages of neuronal polarization, which was mediated by lowered energy status and AMPK activation. Liver kinase B1 and PI3K–Akt–GSK3β signaling pathways were also involved. In addition, mitochondrial dysfunction and endoplasmic reticulum stress contributed to the lowered energy status induced by BBR. This study highlighted the knowledge of the complex activities of BBR in neurons and corroborated the significance of energy status during the neuronal polarization. - Highlights: • BBR inhibited neurite outgrowth in early stages of neuronal development. • Lowered neuronal energy status was induced by BBR treatment. • Neuronal energy stress induced by BBR activated AMPK-related pathways. • BBR induced mitochondrial dysfunction and endoplasmic reticulum stress.

  20. Drosophila MOF regulates DIAP1 and induces apoptosis in a JNK dependent pathway.

    Science.gov (United States)

    Pushpavalli, Sreerangam N C V L; Sarkar, Arpita; Ramaiah, M Janaki; Koteswara Rao, G; Bag, Indira; Bhadra, Utpal; Pal-Bhadra, Manika

    2016-03-01

    Histone modulations have been implicated in various cellular and developmental processes where in Drosophila Mof is involved in acetylation of H4K16. Reduction in the size of larval imaginal discs is observed in the null mutants of mof with increased apoptosis. Deficiency involving Hid, Reaper and Grim [H99] alleviated mof (RNAi) induced apoptosis in the eye discs. mof (RNAi) induced apoptosis leads to activation of caspases which is suppressed by over expression of caspase inhibitors like P35 and Diap1 clearly depicting the role of caspases in programmed cell death. Also apoptosis induced by knockdown of mof is rescued by JNK mutants of bsk and tak1 indicating the role of JNK in mof (RNAi) induced apoptosis. The adult eye ablation phenotype produced by ectopic expression of Hid, Rpr and Grim, was restored by over expression of Mof. Accumulation of Mof at the Diap1 promoter 800 bp upstream of the transcription start site in wild type larvae is significantly higher (up to twofolds) compared to mof (1) mutants. This enrichment coincides with modification of histone H4K16Ac indicating an induction of direct transcriptional up regulation of Diap1 by Mof. Based on these results we propose that apoptosis triggered by mof (RNAi) proceeds through a caspase-dependent and JNK mediated pathway.

  1. δ-Catenin Regulates Spine Architecture via Cadherin and PDZ-dependent Interactions*

    Science.gov (United States)

    Yuan, Li; Seong, Eunju; Beuscher, James L.; Arikkath, Jyothi

    2015-01-01

    The ability of neurons to maintain spine architecture and modulate it in response to synaptic activity is a crucial component of the cellular machinery that underlies information storage in pyramidal neurons of the hippocampus. Here we show a critical role for δ-catenin, a component of the cadherin-catenin cell adhesion complex, in regulating spine head width and length in pyramidal neurons of the hippocampus. The loss of Ctnnd2, the gene encoding δ-catenin, has been associated with the intellectual disability observed in the cri du chat syndrome, suggesting that the functional roles of δ-catenin are vital for neuronal integrity and higher order functions. We demonstrate that loss of δ-catenin in a mouse model or knockdown of δ-catenin in pyramidal neurons compromises spine head width and length, without altering spine dynamics. This is accompanied by a reduction in the levels of synaptic N-cadherin. The ability of δ-catenin to modulate spine architecture is critically dependent on its ability to interact with cadherin and PDZ domain-containing proteins. We propose that loss of δ-catenin during development perturbs synaptic architecture leading to developmental aberrations in neural circuit formation that contribute to the learning disabilities in a mouse model and humans with cri du chat syndrome. PMID:25724647

  2. δ-Catenin Regulates Spine Architecture via Cadherin and PDZ-dependent Interactions.

    Science.gov (United States)

    Yuan, Li; Seong, Eunju; Beuscher, James L; Arikkath, Jyothi

    2015-04-24

    The ability of neurons to maintain spine architecture and modulate it in response to synaptic activity is a crucial component of the cellular machinery that underlies information storage in pyramidal neurons of the hippocampus. Here we show a critical role for δ-catenin, a component of the cadherin-catenin cell adhesion complex, in regulating spine head width and length in pyramidal neurons of the hippocampus. The loss of Ctnnd2, the gene encoding δ-catenin, has been associated with the intellectual disability observed in the cri du chat syndrome, suggesting that the functional roles of δ-catenin are vital for neuronal integrity and higher order functions. We demonstrate that loss of δ-catenin in a mouse model or knockdown of δ-catenin in pyramidal neurons compromises spine head width and length, without altering spine dynamics. This is accompanied by a reduction in the levels of synaptic N-cadherin. The ability of δ-catenin to modulate spine architecture is critically dependent on its ability to interact with cadherin and PDZ domain-containing proteins. We propose that loss of δ-catenin during development perturbs synaptic architecture leading to developmental aberrations in neural circuit formation that contribute to the learning disabilities in a mouse model and humans with cri du chat syndrome. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. VHL-dependent regulation of a β-dystroglycan glycoform and glycogene expression in renal cancer.

    Science.gov (United States)

    Aggelis, Vassilis; Craven, Rachel A; Peng, Jianhe; Harnden, Patricia; Schaffer, Lana; Hernandez, Gilberto E; Head, Steven R; Maher, Eamonn R; Tonge, Robert; Selby, Peter J; Banks, Rosamonde E

    2013-11-01

    Identification of novel biomarkers and targets in renal cell carcinoma (RCC) remains a priority and one cellular compartment that is a rich potential source of such molecules is the plasma membrane. A shotgun proteomic analysis of cell surface proteins enriched by cell surface biotinylation and avidin affinity chromatography was explored using the UMRC2- renal cancer cell line, which lacks von Hippel-Lindau (VHL) tumour suppressor gene function, to determine whether proteins of interest could be detected. Of the 814 proteins identified ~22% were plasma membrane or membrane-associated, including several with known associations with cancer. This included β-dystroglycan, the transmembrane subunit of the DAG1 gene product. VHL-dependent changes in the form of β-dystroglycan were detected in UMRC2-/+VHL transfectants. Deglycosylation experiments showed that this was due to differential sialylation. Analysis of normal kidney cortex and conventional RCC tissues showed that a similar change also occurred in vivo. Investigation of the expression of genes involved in glycosylation in UMRC2-/+VHL cells using a focussed microarray highlighted a number of enzymes involved in sialylation; upregulation of bifunctional UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) was validated in UMRC2- cells compared with their +VHL counterparts and also found in conventional RCC tissue. These results implicate VHL in the regulation of glycosylation and raise interesting questions regarding the extent and importance of such changes in RCC.

  4. Activity-Dependent Exocytosis of Lysosomes Regulates the Structural Plasticity of Dendritic Spines.

    Science.gov (United States)

    Padamsey, Zahid; McGuinness, Lindsay; Bardo, Scott J; Reinhart, Marcia; Tong, Rudi; Hedegaard, Anne; Hart, Michael L; Emptage, Nigel J

    2017-01-04

    Lysosomes have traditionally been viewed as degradative organelles, although a growing body of evidence suggests that they can function as Ca 2+ stores. Here we examined the function of these stores in hippocampal pyramidal neurons. We found that back-propagating action potentials (bpAPs) could elicit Ca 2+ release from lysosomes in the dendrites. This Ca 2+ release triggered the fusion of lysosomes with the plasma membrane, resulting in the release of Cathepsin B. Cathepsin B increased the activity of matrix metalloproteinase 9 (MMP-9), an enzyme involved in extracellular matrix (ECM) remodelling and synaptic plasticity. Inhibition of either lysosomal Ca 2+ signaling or Cathepsin B release prevented the maintenance of dendritic spine growth induced by Hebbian activity. This impairment could be rescued by exogenous application of active MMP-9. Our findings suggest that activity-dependent exocytosis of Cathepsin B from lysosomes regulates the long-term structural plasticity of dendritic spines by triggering MMP-9 activation and ECM remodelling. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

  5. Nardilysin controls intestinal tumorigenesis through HDAC1/p53-dependent transcriptional regulation.

    Science.gov (United States)

    Kanda, Keitaro; Sakamoto, Jiro; Matsumoto, Yoshihide; Ikuta, Kozo; Goto, Norihiro; Morita, Yusuke; Ohno, Mikiko; Nishi, Kiyoto; Eto, Koji; Kimura, Yuto; Nakanishi, Yuki; Ikegami, Kanako; Yoshikawa, Takaaki; Fukuda, Akihisa; Kawada, Kenji; Sakai, Yoshiharu; Ito, Akihiro; Yoshida, Minoru; Kimura, Takeshi; Chiba, Tsutomu; Nishi, Eiichiro; Seno, Hiroshi

    2018-04-19

    Colon cancer is a complex disease affected by a combination of genetic and epigenetic factors. Here we demonstrate that nardilysin (N-arginine dibasic convertase; NRDC), a metalloendopeptidase of the M16 family, regulates intestinal tumorigenesis via its nuclear functions. NRDC is highly expressed in human colorectal cancers. Deletion of the Nrdc gene in ApcMin mice crucially suppressed intestinal tumor development. In ApcMin mice, epithelial cell-specific deletion of Nrdc recapitulated the tumor suppression observed in Nrdc-null mice. Moreover, epithelial cell-specific overexpression of Nrdc significantly enhanced tumor formation in ApcMin mice. Notably, epithelial NRDC controlled cell apoptosis in a gene dosage-dependent manner. In human colon cancer cells, nuclear NRDC directly associated with HDAC1, and controlled both acetylation and stabilization of p53, with alterations of p53 target apoptotic factors. These findings demonstrate that NRDC is critically involved in intestinal tumorigenesis through its epigenetic regulatory function, and targeting NRDC may lead to a novel prevention or therapeutic strategy against colon cancer.

  6. Berberine regulates neurite outgrowth through AMPK-dependent pathways by lowering energy status

    International Nuclear Information System (INIS)

    Lu, Jiaqi; Cao, Yuanzhao; Cheng, Kuoyuan; Xu, Bo; Wang, Tianchang; Yang, Qi; Yang, Qin; Feng, Xudong; Xia, Qing

    2015-01-01

    As a widely used anti-bacterial agent and a metabolic inhibitor as well as AMP-activated protein kinase (AMPK) activator, berberine (BBR) has been shown to cross the blood–brain barrier. Its efficacy has been investigated in various disease models of the central nervous system. Neurite outgrowth is critical for nervous system development and is a highly energy-dependent process regulated by AMPK-related pathways. In the present study, we aimed to investigate the effects of BBR on AMPK activation and neurite outgrowth in neurons. The neurite outgrowth of primary rat cortical neurons at different stages of polarization was monitored after exposure of BBR. Intracellular energy level, AMPK activation and polarity-related pathways were also inspected. The results showed that BBR suppressed neurite outgrowth and affected cytoskeleton stability in the early stages of neuronal polarization, which was mediated by lowered energy status and AMPK activation. Liver kinase B1 and PI3K–Akt–GSK3β signaling pathways were also involved. In addition, mitochondrial dysfunction and endoplasmic reticulum stress contributed to the lowered energy status induced by BBR. This study highlighted the knowledge of the complex activities of BBR in neurons and corroborated the significance of energy status during the neuronal polarization. - Highlights: • BBR inhibited neurite outgrowth in early stages of neuronal development. • Lowered neuronal energy status was induced by BBR treatment. • Neuronal energy stress induced by BBR activated AMPK-related pathways. • BBR induced mitochondrial dysfunction and endoplasmic reticulum stress

  7. Cell-cycle-dependent regulation of cell motility and determination of the role of Rac1

    DEFF Research Database (Denmark)

    Walmod, Peter S.; Hartmann-Petersen, Rasmus; Prag, S.

    2004-01-01

    comparable to those of control cells in G1. In contrast, transfection with dominant-negative Rac1 reduced cell speed and resulted in cellular displacements, which were identical in G1 and G2. These observations indicate that migration of cultured cells is regulated in a cell-cycle-dependent manner...... for calculation of three key parameters describing cell motility: speed, persistence time and rate of diffusion. All investigated cell lines demonstrated a lower cell displacement in the G2 phase than in the G1/S phases. This was caused by a decrease in speed and/or persistence time. The decrease in motility...... was accompanied by changes in morphology reflecting the larger volume of cells in G2 than in G1. Furthermore, L-cells and HeLa-cells appeared to be less adherent in the G2 phase. Transfection of L-cells with constitutively active Rac1 led to a general increase in the speed and rate of diffusion in G2 to levels...

  8. The Eag domain regulates the voltage-dependent inactivation of rat Eag1 K+ channels.

    Directory of Open Access Journals (Sweden)

    Ting-Feng Lin

    Full Text Available Eag (Kv10 and Erg (Kv11 belong to two distinct subfamilies of the ether-à-go-go K+ channel family (KCNH. While Erg channels are characterized by an inward-rectifying current-voltage relationship that results from a C-type inactivation, mammalian Eag channels display little or no voltage-dependent inactivation. Although the amino (N-terminal region such as the eag domain is not required for the C-type inactivation of Erg channels, an N-terminal deletion in mouse Eag1 has been shown to produce a voltage-dependent inactivation. To further discern the role of the eag domain in the inactivation of Eag1 channels, we generated N-terminal chimeras between rat Eag (rEag1 and human Erg (hERG1 channels that involved swapping the eag domain alone or the complete cytoplasmic N-terminal region. Functional analyses indicated that introduction of the homologous hERG1 eag domain led to both a fast phase and a slow phase of channel inactivation in the rEag1 chimeras. By contrast, the inactivation features were retained in the reverse hERG1 chimeras. Furthermore, an eag domain-lacking rEag1 deletion mutant also showed the fast phase of inactivation that was notably attenuated upon co-expression with the rEag1 eag domain fragment, but not with the hERG1 eag domain fragment. Additionally, we have identified a point mutation in the S4-S5 linker region of rEag1 that resulted in a similar inactivation phenotype. Biophysical analyses of these mutant constructs suggested that the inactivation gating of rEag1 was distinctly different from that of hERG1. Overall, our findings are consistent with the notion that the eag domain plays a critical role in regulating the inactivation gating of rEag1. We propose that the eag domain may destabilize or mask an inherent voltage-dependent inactivation of rEag1 K+ channels.

  9. State-Dependent Differences in Emotion Regulation Between Unmedicated Bipolar Disorder and Major Depressive Disorder

    NARCIS (Netherlands)

    Rive, M.M.; Mocking, R.J.T.; Koeter, M.W.; Wingen, G. van; Wit, S.J. de; Heuvel, O.A. van den; Veltman, D.J.; Ruhe, H.G.; Schene, A.H.

    2015-01-01

    IMPORTANCE: Major depressive disorder (MDD) and bipolar disorder (BD) are difficult to distinguish clinically during the depressed or remitted states. Both mood disorders are characterized by emotion regulation disturbances; however, little is known about emotion regulation differences between MDD

  10. State-Dependent Differences in Emotion Regulation Between Unmedicated Bipolar Disorder and Major Depressive Disorder

    NARCIS (Netherlands)

    Rive, Maria M.; Mocking, Roel J. T.; Koeter, Maarten W. J.; van Wingen, Guido; de Wit, Stella J.; van den Heuvel, Odile A.; Veltman, Dick J.; Ruhe, Henricus G.; Schene, Aart H.

    IMPORTANCE Major depressive disorder (MDD) and bipolar disorder (BD) are difficult to distinguish clinically during the depressed or remitted states. Both mood disorders are characterized by emotion regulation disturbances; however, little is known about emotion regulation differences between MDD

  11. State-Dependent Differences in Emotion Regulation Between Unmedicated Bipolar Disorder and Major Depressive Disorder

    NARCIS (Netherlands)

    Rive, M.M.; Mocking, R.J.T.; Koeter, M.W.J.; van Wingen, G.; de Wit, S.J.; van den Heuvel, O.A.; Veltman, D.J.; Ruhe, H.G.; Schene, A.H.

    2015-01-01

    IMPORTANCE Major depressive disorder (MDD) and bipolar disorder (BD) are difficult to distinguish clinically during the depressed or remitted states. Both mood disorders are characterized by emotion regulation disturbances; however, little is known about emotion regulation differences between MDD

  12. Ethylene regulates Apple (Malus x domestica) fruit softening through a dose x time-dependent mechanism and through differential sensitivities and dependencies of cell wall-modifying genes.

    Science.gov (United States)

    Ireland, Hilary S; Gunaseelan, Kularajathevan; Muddumage, Ratnasiri; Tacken, Emma J; Putterill, Jo; Johnston, Jason W; Schaffer, Robert J

    2014-05-01

    In fleshy fruit species that have a strong requirement for ethylene to ripen, ethylene is synthesized autocatalytically, producing increasing concentrations as the fruits ripen. Apple fruit with the ACC OXIDASE 1 (ACO1) gene suppressed cannot produce ethylene autocatalytically at ripening. Using these apple lines, an ethylene sensitivity dependency model was previously proposed, with traits such as softening showing a high dependency for ethylene as well as low sensitivity. In this study, it is shown that the molecular control of fruit softening is a complex process, with different cell wall-related genes being independently regulated and exhibiting differential sensitivities to and dependencies on ethylene at the transcriptional level. This regulation is controlled through a dose × time mechanism, which results in a temporal transcriptional response that would allow for progressive cell wall disassembly and thus softening. This research builds on the sensitivity dependency model and shows that ethylene-dependent traits can progress over time to the same degree with lower levels of ethylene. This suggests that a developmental clock measuring cumulative ethylene controls the fruit ripening process.

  13. MicroRNA-223 controls susceptibility to tuberculosis by regulating lung neutrophil recruitment.

    Science.gov (United States)

    Dorhoi, Anca; Iannaccone, Marco; Farinacci, Maura; Faé, Kellen C; Schreiber, Jörg; Moura-Alves, Pedro; Nouailles, Geraldine; Mollenkopf, Hans-Joachim; Oberbeck-Müller, Dagmar; Jörg, Sabine; Heinemann, Ellen; Hahnke, Karin; Löwe, Delia; Del Nonno, Franca; Goletti, Delia; Capparelli, Rosanna; Kaufmann, Stefan H E

    2013-11-01

    The molecular mechanisms that control innate immune cell trafficking during chronic infection and inflammation, such as in tuberculosis (TB), are incompletely understood. During active TB, myeloid cells infiltrate the lung and sustain local inflammation. While the chemoattractants that orchestrate these processes are increasingly recognized, the posttranscriptional events that dictate their availability are unclear. We identified microRNA-223 (miR-223) as an upregulated small noncoding RNA in blood and lung parenchyma of TB patients and during murine TB. Deletion of miR-223 rendered TB-resistant mice highly susceptible to acute lung infection. The lethality of miR-223(–/–) mice was apparently not due to defects in antimycobacterial T cell responses. Exacerbated TB in miR-223(–/–) animals could be partially reversed by neutralization of CXCL2, CCL3, and IL-6, by mAb depletion of neutrophils, and by genetic deletion of Cxcr2. We found that miR-223 controlled lung recruitment of myeloid cells, and consequently, neutrophil-driven lethal inflammation. We conclude that miR-223 directly targets the chemoattractants CXCL2, CCL3, and IL-6 in myeloid cells. Our study not only reveals an essential role for a single miRNA in TB, it also identifies new targets for, and assigns biological functions to, miR-223. By regulating leukocyte chemotaxis via chemoattractants, miR-223 is critical for the control of TB and potentially other chronic inflammatory diseases.

  14. DJ-1-dependent regulation of oxidative stress in the retinal pigment epithelium (RPE.

    Directory of Open Access Journals (Sweden)

    Karen G Shadrach

    Full Text Available DJ-1 is found in many tissues, including the brain, where it has been extensively studied due to its association with Parkinson's disease. DJ-1 functions as a redox-sensitive molecular chaperone and transcription regulator that robustly protects cells from oxidative stress.Retinal pigment epithelial (RPE cultures were treated with H2O2 for various times followed by biochemical and immunohistological analysis. Cells were transfected with adenoviruses carrying the full-length human DJ-1 cDNA and a mutant construct, which has the cysteine residues at amino acid 46, 53 and 106 mutated to serine (C to S prior to stress experiments. DJ-1 localization, levels of expression and reactive oxygen species (ROS generation were also analyzed in cells expressing exogenous DJ-1 under baseline and oxidative stress conditions. The presence of DJ-1 and oxidized DJ-1 was evaluated in human RPE total lysates. The distribution of DJ-1 was assessed in AMD and non-AMD cryosectionss and in isolated human Bruch's membrane (BM/choroid from AMD eyes.DJ-1 in RPE cells under baseline conditions, displays a diffuse cytoplasmic and nuclear staining. After oxidative challenge, more DJ-1 was associated with mitochondria. Increasing concentrations of H2O2 resulted in a dose-dependent increase in DJ-1. Overexpression of DJ-1 but not the C to S mutant prior to exposure to oxidative stress led to significant decrease in the generation of ROS. DJ-1 and oxDJ-1 intensity of immunoreactivity was significantly higher in the RPE lysates from AMD eyes. More DJ-1 was localized to RPE cells from AMD donors with geographic atrophy and DJ-1 was also present in isolated human BM/choroid from AMD eyes.DJ-1 regulates RPE responses to oxidative stress. Most importantly, increased DJ-1 expression prior to oxidative stress leads to decreased generation of ROS, which will be relevant for future studies of AMD since oxidative stress is a known factor affecting this disease.

  15. Exercise dependence score in patients with longstanding eating disorders and controls: the importance of affect regulation and physical activity intensity.

    Science.gov (United States)

    Bratland-Sanda, Solfrid; Martinsen, Egil W; Rosenvinge, Jan H; Rø, Oyvind; Hoffart, Asle; Sundgot-Borgen, Jorunn

    2011-01-01

    To examine associations among exercise dependence score, amount of physical activity and eating disorder (ED) symptoms in patients with longstanding ED and non-clinical controls. Adult female inpatients (n = 59) and 53 age-matched controls participated in this cross sectional study. Assessments included the eating disorders examination, eating disorders inventory, exercise dependence scale, reasons for exercise inventory, and MTI Actigraph accelerometer. Positive associations were found among vigorous, not moderate, physical activity, exercise dependence score and ED symptoms in patients. In the controls, ED symptoms were negatively associated with vigorous physical activity and not correlated with exercise dependence score. Exercise for negative affect regulation, not weight/appearance, and amount of vigorous physical activity were explanatory variables for exercise dependence score in both groups. The positive associations among exercise dependence score, vigorous physical activity and ED symptoms need proper attention in the treatment of longstanding ED. Copyright © 2011 John Wiley & Sons, Ltd and Eating Disorders Association.

  16. Phosphatidylserine Sensing by TAM Receptors Regulates AKT-Dependent Chemoresistance and PD-L1 Expression.

    Science.gov (United States)

    Kasikara, Canan; Kumar, Sushil; Kimani, Stanley; Tsou, Wen-I; Geng, Ke; Davra, Viralkumar; Sriram, Ganapathy; Devoe, Connor; Nguyen, Khanh-Quynh N; Antes, Anita; Krantz, Allen; Rymarczyk, Grzegorz; Wilczynski, Andrzej; Empig, Cyril; Freimark, Bruce; Gray, Michael; Schlunegger, Kyle; Hutchins, Jeff; Kotenko, Sergei V; Birge, Raymond B

    2017-06-01

    Tyro3, Axl, and Mertk (collectively TAM receptors) are three homologous receptor tyrosine kinases that bind vitamin K-dependent endogenous ligands, Protein S (ProS), and growth arrest-specific factor 6 (Gas6), and act as bridging molecules to promote phosphatidylserine (PS)-mediated clearance of apoptotic cells (efferocytosis). TAM receptors are overexpressed in a vast array of tumor types, whereby the level of expression correlates with the tumor grade and the emergence of chemo- and radioresistance to targeted therapeutics, but also have been implicated as inhibitory receptors on infiltrating myeloid-derived cells in the tumor microenvironment that can suppress host antitumor immunity. In the present study, we utilized TAM-IFNγR1 reporter lines and expressed TAM receptors in a variety of epithelial cell model systems to show that each TAM receptor has a unique pattern of activation by Gas6 or ProS, as well as unique dependency for PS on apoptotic cells and PS liposomes for activity. In addition, we leveraged this system to engineer epithelial cells that express wild-type TAM receptors and show that although each receptor can promote PS-mediated efferocytosis, AKT-mediated chemoresistance, as well as upregulate the immune checkpoint molecule PD-L1 on tumor cells, Mertk is most dominant in the aforementioned pathways. Functionally, TAM receptor-mediated efferocytosis could be partially blocked by PS-targeting antibody 11.31 and Annexin V, demonstrating the existence of a PS/PS receptor (i.e., TAM receptor)/PD-L1 axis that operates in epithelial cells to foster immune escape. These data provide a rationale that PS-targeting, anti-TAM receptor, and anti-PD-L1-based therapeutics will have merit as combinatorial checkpoint inhibitors. Implications: Many tumor cells are known to upregulate the immune checkpoint inhibitor PD-L1. This study demonstrates a role for PS and TAM receptors in the regulation of PD-L1 on cancer cells. Mol Cancer Res; 15(6); 753-64. ©2017 AACR

  17. SPAG6 regulates cell apoptosis through the TRAIL signal pathway in myelodysplastic syndromes.

    Science.gov (United States)

    Li, Xinxin; Yang, Bihui; Wang, Li; Chen, Liping; Luo, Xiaohua; Liu, Lin

    2017-05-01

    Myelodysplastic syndromes (MDSs) are a group of malignant clone hematopoietic stem-cell diseases, and the evolution and progression of MDS depend on the abnormal apoptosis of bone marrow cells. Our previous studies have indicated that sperm-associated antigen 6 (SPAG6), located in the uniparental disomy regions of myeloid cells, is overexpressed in patients with MDS as compared to controls, and SPAG6 can inhibit apoptosis of SKM-1. However, the concrete mechanism is still unclear. In the present study, it was found that the TNF-related apoptosis-inducing ligand (TRAIL)signal pathway was activated when the expression of SPAG6 was inhibited by SPAG6-shRNA lentivirus in SKM-1 cells. Additionally, the results of flow cytometry, Cell Counting Kit-8 assay and western blot analysis implied that the TRAIL signal pathway could be inhibited by a high expression of SPAG6. However, SPAG6 cannot influence the expression of TRAIL death receptors, except for FADD. Additionally the interaction between FADD and TRAIL death receptors also increased in SKM-1 cells infected with SPAG6-shRNA lentivirus. Thus, our study demonstrates that SPAG6 may regulate apoptosis in SKM-1 through the TRAIL signal pathway, indicating that SPAG6 could be a potential therapeutic target.

  18. Hormonal regulation of Na+/K+-dependent ATPase activity and pump function in corneal endothelial cells.

    Science.gov (United States)

    Hatou, Shin

    2011-10-01

    Na- and K-dependent ATPase (Na,K-ATPase) in the basolateral membrane of corneal endothelial cells plays an important role in the pump function of the corneal endothelium. We investigated the role of dexamethasone in the regulation of Na,K-ATPase activity and pump function in these cells. Mouse corneal endothelial cells were exposed to dexamethasone or insulin. ATPase activity was evaluated by spectrophotometric measurement, and pump function was measured using an Ussing chamber. Western blotting and immunocytochemistry were performed to measure the expression of the Na,K-ATPase α1-subunit. Dexamethasone increased Na,K-ATPase activity and the pump function of endothelial cells. Western blot analysis indicated that dexamethasone increased the expression of the Na,K-ATPase α1-subunit but decreased the ratio of active to inactive Na,K-ATPase α1-subunit. Insulin increased Na,K-ATPase activity and pump function of cultured corneal endothelial cells. These effects were transient and blocked by protein kinase C inhibitors and inhibitors of protein phosphatases 1 (PP1) and 2A (PP2A). Western blot analysis indicated that insulin decreased the amount of inactive Na,K-ATPase α1-subunit, but the expression of total Na,K-ATPase α1-subunit was unchanged. Immunocytochemistry showed that insulin increased cell surface expression of the Na,K-ATPase α1-subunit. Our results suggest that dexamethasone and insulin stimulate Na,K-ATPase activity in mouse corneal endothelial cells. The effect of dexamethasone activation in these cells was mediated by Na,K-ATPase synthesis and an increased enzymatic activity because of dephosphorylation of Na,K-ATPase α1-subunits. The effect of insulin is mediated by the protein kinase C, PP1, and/or PP2A pathways.

  19. Acetylcholinesterase Regulates Skeletal In Ovo Development of Chicken Limbs by ACh-Dependent and -Independent Mechanisms.

    Directory of Open Access Journals (Sweden)

    Janine Spieker

    Full Text Available Formation of the vertebrate limb presents an excellent model to analyze a non-neuronal cholinergic system (NNCS. Here, we first analyzed the expression of acetylcholinesterase (AChE by IHC and of choline acetyltransferase (ChAT by ISH in developing embryonic chicken limbs (stages HH17-37. AChE outlined formation of bones, being strongest at their distal tips, and later also marked areas of cell death. At onset, AChE and ChAT were elevated in two organizing centers of the limb anlage, the apical ectodermal ridge (AER and zone of polarizing activity (ZPA, respectively. Thereby ChAT was expressed shortly after AChE, thus strongly supporting a leading role of AChE in limb formation. Then, we conducted loss-of-function studies via unilateral implantation of beads into chicken limb anlagen, which were soaked in cholinergic components. After varying periods, the formation of cartilage matrix and of mineralizing bones was followed by Alcian blue (AB and Alizarin red (AR stainings, respectively. Both acetylcholine (ACh- and ChAT-soaked beads accelerated bone formation in ovo. Notably, inhibition of AChE by BW284c51, or by the monoclonal antibody MAB304 delayed cartilage formation. Since bead inhibition of BChE was mostly ineffective, an ACh-independent action during BW284c51 and MAB304 inhibition was indicated, which possibly could be due to an enzymatic side activity of AChE. In conclusion, skeletogenesis in chick is regulated by an ACh-dependent cholinergic system, but to some extent also by an ACh-independent aspect of the AChE protein.

  20. Age-Dependent Schwann Cell Phenotype Regulation Following Peripheral Nerve Injury.

    Science.gov (United States)

    Chen, Wayne A; Luo, T David; Barnwell, Jonathan C; Smith, Thomas L; Li, Zhongyu

    2017-12-01

    Schwann cells are integral to the regenerative capacity of the peripheral nervous system, which declines after adolescence. The mechanisms underlying this decline are poorly understood. This study sought to compare the protein expression of Notch, c-Jun, and Krox-20 after nerve crush injury in adolescent and young adult rats. We hypothesized that these Schwann cell myelinating regulatory factors are down-regulated after nerve injury in an age-dependent fashion. Adolescent (2 months old) and young adult (12 months old) rats (n = 48) underwent sciatic nerve crush injury. Protein expression of Notch, c-Jun, and Krox-20 was quantified by Western blot analysis at 1, 3, and 7 days post-injury. Functional recovery was assessed in a separate group of animals (n = 8) by gait analysis (sciatic functional index) and electromyography (compound motor action potential) over an 8-week post-injury period. Young adult rats demonstrated a trend of delayed onset of the dedifferentiating regulatory factors, Notch and c-Jun, corresponding to the delayed functional recovery observed in young adult rats compared to adolescent rats. Compound motor action potential area was significantly greater in adolescent rats relative to young adult rats, while amplitude and velocity trended toward statistical significance. The process of Schwann cell dedifferentiation following peripheral nerve injury shows different trends with age. These trends of delayed onset of key regulatory factors responsible for Schwann cell myelination may be one of many possible factors mediating the significant differences in functional recovery between adolescent and young adult rats following peripheral nerve injury.

  1. Context-dependent regulation of feeding behaviour by the insulin receptor, DAF-2, in Caenorhabditis elegans.

    Science.gov (United States)

    Dillon, James; Holden-Dye, Lindy; O'Connor, Vincent; Hopper, Neil A

    2016-06-01

    Insulin signalling plays a significant role in both developmental programmes and pathways modulating the neuronal signalling that controls adult behaviour. Here, we have investigated insulin signalling in food-associated behaviour in adult C. elegans by scoring locomotion and feeding on and off bacteria, the worm's food. This analysis used mutants (daf-2, daf-18) of the insulin signalling pathway, and we provide evidence for an acute role for insulin signalling in the adult nervous system distinct from its impact on developmental programmes. Insulin receptor daf-2 mutants move slower than wild type both on and off food and showed impaired locomotory responses to food deprivation. This latter behaviour is manifest as a failure to instigate dispersal following prolonged food deprivation and suggests a role for insulin signalling in this adaptive response. Insulin receptor daf-2 mutants are also deficient in pharyngeal pumping on food and off food. Pharmacological analysis showed the pharynx of daf-2 is selectively compromised in its response to 5-HT compared to the excitatory neuropeptide FLP-17. By comparing the adaptive pharyngeal behaviour in intact worms and isolated pharyngeal preparations, we determined that an insulin-dependent signal extrinsic to the pharyngeal system is involved in feeding adaptation. Hence, we suggest that reactive insulin signalling modulates both locomotory foraging and pharyngeal pumping as the animal adapts to the absence of food. We discuss this in the context of insulin signalling directing a shift in the sensitivity of neurotransmitter systems to regulate the worm's response to changes in food availability in the environment.

  2. Emotion Generation and Emotion Regulation: One or Two Depends on Your Point of View

    OpenAIRE

    Gross, James J.; Barrett, Lisa Feldman

    2011-01-01

    Emotion regulation has the odd distinction of being a wildly popular construct whose scientific existence is in considerable doubt. In this article, we discuss the confusion about whether emotion generation and emotion regulation can and should be distinguished from one another. We describe a continuum of perspectives on emotion, and highlight how different (often mutually incompatible) perspectives on emotion lead to different views about whether emotion generation and emotion regulation can...

  3. Glucagon Couples Hepatic Amino Acid Catabolism to mTOR-Dependent Regulation of α-Cell Mass

    Directory of Open Access Journals (Sweden)

    Mark J. Solloway

    2015-07-01

    Full Text Available Understanding the regulation of islet cell mass has important implications for the discovery of regenerative therapies for diabetes. The liver plays a central role in metabolism and the regulation of endocrine cell number, but liver-derived factors that regulate α-cell and β-cell mass remain unidentified. We propose a nutrient-sensing circuit between liver and pancreas in which glucagon-dependent control of hepatic amino acid metabolism regulates α-cell mass. We found that glucagon receptor inhibition reduced hepatic amino acid catabolism, increased serum amino acids, and induced α-cell proliferation in an mTOR-dependent manner. In addition, mTOR inhibition blocked amino-acid-dependent α-cell replication ex vivo and enabled conversion of α-cells into β-like cells in vivo. Serum amino acids and α-cell proliferation were increased in neonatal mice but fell throughout postnatal development in a glucagon-dependent manner. These data reveal that amino acids act as sensors of glucagon signaling and can function as growth factors that increase α-cell proliferation.

  4. Arabidopsis MAP kinase 4 regulates salicylic acid- and jasmonic acid/ethylene-dependent responses via EDS1 and PAD4

    DEFF Research Database (Denmark)

    Brodersen, P; Petersen, M; Nielsen, Henrik Bjørn

    2006-01-01

    Arabidopsis MPK4 has been implicated in plant defense regulation because mpk4 knockout plants exhibit constitutive activation of salicylic acid (SA)-dependent defenses, but fail to induce jasmonic acid (JA) defense marker genes in response to JA. We show here that mpk4 mutants are also defective...

  5. Mechanism of Ca2+/calmodulin-dependent kinase II regulation of AMPA receptor gating

    DEFF Research Database (Denmark)

    Kristensen, Anders Skov; Jenkins, Meagan A; Banke, Tue G

    2011-01-01

    The function, trafficking and synaptic signaling of AMPA receptors are tightly regulated by phosphorylation. Ca(2+)/calmodulin-dependent kinase II (CaMKII) phosphorylates the GluA1 AMPA receptor subunit at Ser831 to increase single-channel conductance. We show that CaMKII increases the conductanc...

  6. Regulation of expression of Na+,K+-ATPase in androgen-dependent and androgen-independent prostate cancer

    NARCIS (Netherlands)

    L.J. Blok (Leen); G.T.G. Chang; M. Steenbeek-Slotboom (M.); W.M. van Weerden (Wytske); H.G. Swarts; J.J.H.H.M. de Pont (J. J H H M); G.J. van Steenbrugge (Gert Jan); A.O. Brinkmann (Albert)

    1999-01-01

    textabstractThe β1-subunit of Na+,K+-ATPase was isolated and identified as an androgen down-regulated gene. Expression was observed at high levels in androgen-independent as compared to androgen-dependent (responsive) human prostate cancer cell lines and xenografts when grown in the presence of

  7. β-adrenergic receptor-dependent alterations in murine cardiac transcript expression are differentially regulated by gefitinib in vivo.

    Directory of Open Access Journals (Sweden)

    Jennifer A Talarico

    Full Text Available β-adrenergic receptor (βAR-mediated transactivation of epidermal growth factor receptor (EGFR has been shown to promote cardioprotection in a mouse model of heart failure and we recently showed that this mechanism leads to enhanced cell survival in part via regulation of apoptotic transcript expression in isolated primary rat neonatal cardiomyocytes. Thus, we hypothesized that this process could regulate cardiac transcript expression in vivo. To comprehensively assess cardiac transcript alterations in response to acute βAR-dependent EGFR transactivation, we performed whole transcriptome analysis of hearts from C57BL/6 mice given i.p. injections of the βAR agonist isoproterenol in the presence or absence of the EGFR antagonist gefitinib for 1 hour. Total cardiac RNA from each treatment group underwent transcriptome analysis, revealing a substantial number of transcripts regulated by each treatment. Gefitinib alone significantly altered the expression of 405 transcripts, while isoproterenol either alone or in conjunction with gefitinib significantly altered 493 and 698 distinct transcripts, respectively. Further statistical analysis was performed, confirming 473 transcripts whose regulation by isoproterenol were significantly altered by gefitinib (isoproterenol-induced up/downregulation antagonized/promoted by gefinitib, including several known to be involved in the regulation of numerous processes including cell death and survival. Thus, βAR-dependent regulation of cardiac transcript expression in vivo can be modulated by the EGFR antagonist gefitinib.

  8. RhoA Controls Retinoid Signaling by ROCK Dependent Regulation of Retinol Metabolism

    DEFF Research Database (Denmark)

    García-Mariscal, Alberto; Peyrollier, Karine; Basse, Astrid

    2017-01-01

    The ubiquitously expressed small GTPase RhoA is essential for embryonic development and mutated in different cancers. Functionally, it is well described as a regulator of the actin cytoskeleton, but its role in gene regulation is less understood. Using primary mouse keratinocytes with a deletion ...

  9. A Passive Flow-rate Regulator Using Pressure-dependent Autonomous Deflection of Parallel Membrane Valves

    International Nuclear Information System (INIS)

    Il, Doh; Cho, Young-Ho

    2009-01-01

    We present a passive flow-rate regulator, capable to compensate inlet pressure variation and to maintain a constant flow-rate for precise liquid control. Deflection of the parallel membrane valves in the passive flowrate regulator adjusts fluidic resistance according to inlet fluid pressure without any external energy. Compared to previous passive flow-rate regulators, the present device achieves precision flow regulation functions at the lower threshold compensation pressure of 20kPa with the simpler structure. In the experimental study, the fabricated device achieves the constant flow-rate of 6.09±0.32 μl/s over the inlet pressure range of 20∼50 kPa. The present flow-rate regulator having simple structure and lower compensation pressure level demonstrates potentials for use in integrated micropump systems

  10. Cell cycle-dependent regulation of kainate-induced inward currents in microglia

    International Nuclear Information System (INIS)

    Yamada, Jun; Sawada, Makoto; Nakanishi, Hiroshi

    2006-01-01

    Microglia are reported to have α-amino-hydroxy-5-methyl-isoxazole-4-propionate/kainate (KA) types. However, only small population of primary cultured rat microglia (approximately 20%) responded to KA. In the present study, we have attempted to elucidate the regulatory mechanism of responsiveness to KA in GMIR1 rat microglial cell line. When the GMIR1 cells were plated at a low density in the presence of granulocyte macrophage colony-stimulating factor, the proliferation rate increased and reached the peak after 2 days in culture and then gradually decreased because of density-dependent inhibition. At cell proliferation stage, approximately 80% of the GMIR1 cells exhibited glutamate (Glu)- and KA-induced inward currents at cell proliferation stage, whereas only 22.5% of the cells showed responsiveness to Glu and KA at cell quiescent stage. Furthermore, the mean amplitudes of inward currents induced by Glu and KA at cell proliferation stage (13.8 ± 3.0 and 8.4 ± 0.6 pA) were significantly larger than those obtained at cell quiescent stage (4.7 ± 0.8 and 6.2 ± 1.2 pA). In the GMIR1 cells, KA-induced inward currents were markedly inhibited by (RS)-3-(2-carboxybenzyl) willardiine (UBP296), a selective antagonist for KA receptors. The KA-responsive cells also responded to (RS)-2-amino-3-(3-hydroxy-5-tert-butylisoxazol-4-yl) propanoic acid (ATPA), a selective agonist for GluR5, in both GMIR1 cells and primary cultured rat microglia. Furthermore, mRNA levels of the KA receptor subunits, GluR5 and GluR6, at the cell proliferation stage were significantly higher than those at the cell quiescent stage. Furthermore, the immunoreactivity for GluR6/7 was found to increase in activated microglia in the post-ischemic hippocampus. These results strongly suggest that microglia have functional KA receptors mainly consisting of GluR5 and GluR6, and the expression levels of these subunits are closely regulated by the cell cycle mechanism

  11. Regulation strategies for wind power fluctuations depending on demand in Spain

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Martinez, Sergio; Vigueras-Rodriguez, Antonio; Gomez-Lazaro, Emilio [Universidad de Castilla-La Mancha, Albacete (Spain). Energy Research Inst.; Fuentes, Juan Alvaro; Molina-Garcia, Angel [Cartagena Univ. (Spain). Dept. of Electrical Engineering

    2010-07-01

    Power systems need more flexibility as far as significant amounts of load are being covered by wind power. The variations of large wind power production impose some adverse effects on the power system. Some of these effects are the cycling losses on centralized units, discarded wind energy and increase of reserve requirements. Cycling losses derived from a non-optimal operation on great thermal and hydro power plants is an important issue produced by the stochastic wind power nature. Discarded wind energy is produced when the system can not assimilate all the wind power production. Reserve requirements are increased to keep the system balance with the secondary control. Different control functions have been developed for active power production. Some of them are balance control, delta control and power gradient limitation. Balance control consists in adjusting the production in steps to a set point constant production. The delta production constraint consists on limiting the current production to a fix delta power value below the possible production. This constraint is usually used for increasing the regulation capabilities in the wind farm. The Delta constraint can also be used jointly with the negative ramp limiting strategy, allowing then also to fix a maximum negative gradient for the cases in which the wind speed is decreasing and it is possible to limit that descend by reducing the delta value. The power gradient limiting strategy consists in a limitation of the maximum increasing gradient of the current production, i.e. it prevents the farm production from increasing too fast when the wind speed is rising or when the farm is to be started in high wind. It the wind speed is decreasing, then the constraint does not have any function. On the other hand, the negative ramp limiting strategy consists in a limitation of the maximum decreasing gradient of the current production. If the wind speed is increasing, then the constraint does not have any function. This

  12. IQGAP1-dependent signaling pathway regulates endothelial cell proliferation and angiogenesis.

    Directory of Open Access Journals (Sweden)

    Rosana D Meyer

    Full Text Available Vascular endothelial growth factor receptor-2 (VEGFR-2 signaling is an obligate requirement for normal development and pathological angiogenesis such as cancer and age-related macular degeneration. Although autophosphorylation of tyrosine 1173 (Y1173 of VEGFR-2 is considered a focal point for its angiogenic signal relay, however, the mechanism of phosphorylation of Y1173, signaling proteins that are recruited to this residue and their role in angiogenesis is not fully understood.In this study we demonstrate that c-Src kinase directly through its Src homology 2 (SH2 domain and indirectly via c-Cbl binds to phospho-Y1057 of VEGFR-2. Activation of c-Src kinase by a positive feedback mechanism phosphorylates VEGFR-2 at multi-docking site, Y1173. c-Src also catalyzes tyrosine phosphorylation of IQGAP1 and acts as an adaptor to bridge IQGAP1 to VEGFR-2. In turn, IQGAP1 activates b-Raf and mediates proliferation of endothelial cells. Silencing expression of IQGAP1 and b-Raf revealed that their activity is essential for VEGF to stimulate angiogenesis in an in vivo angiogenesis model of chicken chorioallantoic membrane (CAM.Angiogenesis contributes to the pathology of numerous human diseases ranging from cancer to age-related macular degeneration. Determining molecular mechanism of tyrosine phosphorylation of VEGFR-2 and identification of molecules that are relaying its angiogenic signaling may identify novel targets for therapeutic intervention against angiogenesis-associated diseases. Our study shows that recruitment and activation of c-Src by VEGFR-2 plays a pivotal role in relaying angiogenic signaling of VEGFR-2; it phosphorylates VEGFR-2 at Y1173, facilitates association and activation of IQGAP1 and other signaling proteins to VEGFR-2. IQGAP1-dependent signaling, in part, is critically required for endothelial cell proliferation, a key step in angiogenesis. Thus, Y1057 of VEGFR-2 serves to regulate VEGFR-2 function in a combinatorial manner by

  13. p35 regulates the CRM1-dependent nucleocytoplasmic shuttling of nuclear hormone receptor coregulator-interacting factor 1 (NIF-1.

    Directory of Open Access Journals (Sweden)

    Xiao-Su Zhao

    Full Text Available Cyclin-dependent kinase 5 (Cdk5 is a proline-directed serine/threonine kinase, which plays critical roles in a wide spectrum of neuronal functions including neuronal survival, neurite outgrowth, and synapse development and plasticity. Cdk5 activity is controlled by its specific activators: p35 or p39. While knockout studies reveal that Cdk5/p35 is critical for neuronal migration during early brain development, functions of Cdk5/p35 have been unraveled through the identification of the interacting proteins of p35, most of which are Cdk5/p35 substrates. However, it remains unclear whether p35 can regulate neuronal functions independent of Cdk5 activity. Here, we report that a nuclear protein, nuclear hormone receptor coregulator (NRC-interacting factor 1 (NIF-1, is a new interacting partner of p35. Interestingly, p35 regulates the functions of NIF-1 independent of Cdk5 activity. NIF-1 was initially discovered as a transcriptional regulator that enhances the transcriptional activity of nuclear hormone receptors. Our results show that p35 interacts with NIF-1 and regulates its nucleocytoplasmic trafficking via the nuclear export pathway. Furthermore, we identified a nuclear export signal on p35; mutation of this site or blockade of the CRM1/exportin-dependent nuclear export pathway resulted in the nuclear accumulation of p35. Intriguingly, blocking the nuclear export of p35 attenuated the nuclear accumulation of NIF-1. These findings reveal a new p35-dependent mechanism in transcriptional regulation that involves the nucleocytoplasmic shuttling of transcription regulators.

  14. p35 regulates the CRM1-dependent nucleocytoplasmic shuttling of nuclear hormone receptor coregulator-interacting factor 1 (NIF-1).

    Science.gov (United States)

    Zhao, Xiao-Su; Fu, Wing-Yu; Chien, Winnie W Y; Li, Zhen; Fu, Amy K Y; Ip, Nancy Y

    2014-01-01

    Cyclin-dependent kinase 5 (Cdk5) is a proline-directed serine/threonine kinase, which plays critical roles in a wide spectrum of neuronal functions including neuronal survival, neurite outgrowth, and synapse development and plasticity. Cdk5 activity is controlled by its specific activators: p35 or p39. While knockout studies reveal that Cdk5/p35 is critical for neuronal migration during early brain development, functions of Cdk5/p35 have been unraveled through the identification of the interacting proteins of p35, most of which are Cdk5/p35 substrates. However, it remains unclear whether p35 can regulate neuronal functions independent of Cdk5 activity. Here, we report that a nuclear protein, nuclear hormone receptor coregulator (NRC)-interacting factor 1 (NIF-1), is a new interacting partner of p35. Interestingly, p35 regulates the functions of NIF-1 independent of Cdk5 activity. NIF-1 was initially discovered as a transcriptional regulator that enhances the transcriptional activity of nuclear hormone receptors. Our results show that p35 interacts with NIF-1 and regulates its nucleocytoplasmic trafficking via the nuclear export pathway. Furthermore, we identified a nuclear export signal on p35; mutation of this site or blockade of the CRM1/exportin-dependent nuclear export pathway resulted in the nuclear accumulation of p35. Intriguingly, blocking the nuclear export of p35 attenuated the nuclear accumulation of NIF-1. These findings reveal a new p35-dependent mechanism in transcriptional regulation that involves the nucleocytoplasmic shuttling of transcription regulators.

  15. Functional Role of Cyclin-Dependent Kinase 5 in the Regulation of Melanogenesis and Epidermal Structure

    OpenAIRE

    Dong, Changsheng; Yang, Shanshan; Fan, Ruiwen; Ji, Kaiyuan; Zhang, Junzhen; Liu, Xuexian; Hu, Shuaipeng; Xie, Jianshan; Liu, Yu; Gao, Wenjun; Wang, Haidong; Yao, Jianbo; Smith, George W; Herrid, Muren

    2017-01-01

    The mammalian integumentary system plays important roles in body homeostasis, and dysfunction of melanogenesis or epidermal development may lead to a variety of skin diseases, including melanoma. Skin pigmentation in humans and coat color in fleece-producing animals are regulated by many genes. Among them, microphthalmia-associated transcription factor (MITF) and paired-box 3 (PAX3) are at the top of the cascade and regulate activities of many important melanogenic enzymes. Here, we report fo...

  16. The DNA Replication Checkpoint Directly Regulates MBF-Dependent G1/S Transcription▿

    OpenAIRE

    Dutta, Chaitali; Patel, Prasanta K.; Rosebrock, Adam; Oliva, Anna; Leatherwood, Janet; Rhind, Nicholas

    2008-01-01

    The DNA replication checkpoint transcriptionally upregulates genes that allow cells to adapt to and survive replication stress. Our results show that, in the fission yeast Schizosaccharomyces pombe, the replication checkpoint regulates the entire G1/S transcriptional program by directly regulating MBF, the G1/S transcription factor. Instead of initiating a checkpoint-specific transcriptional program, the replication checkpoint targets MBF to maintain the normal G1/S transcriptional program du...

  17. A functional screen implicates microRNA-138-dependent regulation of the depalmitoylation enzyme APT1 in dendritic spine morphogenesis

    DEFF Research Database (Denmark)

    Siegel, Gabriele; Obernosterer, Gregor; Fiore, Roberto

    2009-01-01

    of acyl protein thioesterase 1 (APT1), an enzyme regulating the palmitoylation status of proteins that are known to function at the synapse, including the alpha(13) subunits of G proteins (Galpha(13)). RNA-interference-mediated knockdown of APT1 and the expression of membrane-localized Galpha(13) both...... suppress spine enlargement caused by inhibition of miR-138, suggesting that APT1-regulated depalmitoylation of Galpha(13) might be an important downstream event of miR-138 function. Our results uncover a previously unknown miRNA-dependent mechanism in neurons and demonstrate a previously unrecognized...

  18. Negative feedback regulation of Homer 1a on norepinephrine-dependent cardiac hypertrophy

    Energy Technology Data Exchange (ETDEWEB)

    Chiarello, Carmelina; Bortoloso, Elena; Carpi, Andrea; Furlan, Sandra; Volpe, Pompeo, E-mail: pompeo.volpe@unipd.it

    2013-07-15

    Homers are scaffolding proteins that modulate diverse cell functions being able to assemble signalling complexes. In this study, the presence, sub-cellular distribution and function of Homer 1 was investigated. Homer 1a and Homer 1b/c are constitutively expressed in cardiac muscle of both mouse and rat and in HL-1 cells, a cardiac cell line. As judged by confocal immunofluorescence microscopy, Homer 1a displays sarcomeric and peri-nuclear localization. In cardiomyocytes and cultured HL-1 cells, the hypertrophic agonist norepinephrine (NE) induces α{sub 1}-adrenergic specific Homer 1a over-expression, with a two-to-three-fold increase within 1 h, and no up-regulation of Homer 1b/c, as judged by Western blot and qPCR. In HL-1 cells, plasmid-driven over-expression of Homer 1a partially antagonizes activation of ERK phosphorylation and ANF up-regulation, two well-established, early markers of hypertrophy. At the morphometric level, NE-induced increase of cell size is likewise and partially counteracted by exogenous Homer 1a. Under the same experimental conditions, Homer 1b/c does not have any effect on ANF up-regulation nor on cell hypertrophy. Thus, Homer 1a up-regulation is associated to early stages of cardiac hypertrophy and appears to play a negative feedback regulation on molecular transducers of hypertrophy. -- Highlights: • Homer 1a is constitutively expressed in cardiac tissue. • In HL-1 cells, norepinephrine activates signaling pathways leading to hypertrophy. • Homer 1a up-regulation is an early event of norepinephrine-induced hypertrophy. • Homer 1a plays a negative feedback regulation modulating pathological hypertrophy. • Over-expression of Homer 1a per se does not induce hypertrophy.

  19. Toddler's self-regulation strategies in a challenge context are nap-dependent.

    Science.gov (United States)

    Miller, Alison L; Seifer, Ronald; Crossin, Rebecca; Lebourgeois, Monique K

    2015-06-01

    Early childhood represents a time of developmental changes in both sleep and self-regulation, a construct reflecting the ability to control one's behaviour, attention and emotions when challenged. Links between sleep and self-regulation processes have been proposed, but experimental evidence with young children is lacking. In the current study, we tested the effects of acute sleep restriction (nap deprivation) on toddlers' self-regulation. Healthy children (n = 12; four males; aged 30-36 months (33.9 ± 1.7)) slept on a strict schedule (verified with actigraphy and sleep diaries) for 5 days before each of two afternoon assessments following a nap and a no-nap condition (~11-day protocol). Children were videotaped while attempting an unsolvable puzzle, and 10 mutually exclusive self-regulation strategies were later coded. On average, children lost ~90 min of sleep on the no-nap versus the nap day. Nap deprivation resulted in moderate-to-large effects on self-regulation strategies, with decreases in scepticism (d = 0.77; 7% change), negative self-appraisal (d = 0.92; 5% change) and increases in physical self-soothing (d = 0.68; 10% change), focus on the puzzle piece that would not fit (perseveration; d = 0.50; 9% change) and insistence on completing the unsolvable puzzle (d = 0.91; 10% change). Results suggest that sleep serves an important role in the way that toddlers respond to challenging events in their daily lives. After losing daytime sleep, toddlers were less able to engage effectively in a difficult task and reverted to less mature self-regulation strategies than when they were well rested. Over time, chronically missed sleep may impair young children's self-regulation abilities, resulting in risk for social-emotional, behavioural and school problems. © 2014 European Sleep Research Society.

  20. Toddler’s Self-Regulation Strategies in a Challenge Context are Nap-Dependent

    Science.gov (United States)

    Miller, Alison L.; Seifer, Ronald; Crossin, Rebecca; LeBourgeois, Monique K.

    2015-01-01

    SUMMARY Early childhood represents a time of developmental changes in both sleep and self-regulation, a construct reflecting the ability to control one’s behavior, attention, and emotion when challenged. Links between sleep and self-regulation processes have been proposed, but experimental evidence with young children is lacking. In the current study, we tested the effects of acute sleep restriction (nap deprivation) on toddlers’ self-regulation. Healthy children (n=12; 4 males; 30–36 months (33.9±1.7) slept on a strict schedule (verified with actigraphy and sleep diaries) for 5 days before each of two afternoon assessments following a Nap and a No-Nap condition (~11-day protocol). Children were videotaped while attempting an unsolvable puzzle, and 10 mutually exclusive self-regulation strategies were later coded. On average, children lost ~90 min of sleep on the No-Nap versus the Nap day. Nap deprivation resulted in moderate-to-large effects on self-regulation strategies, with decreases in skepticism (d=0.77; 7% change), negative self-appraisal (d=0.92; 5% change), and increases in physical self-soothing (d=0.68; 10% change), focus on the puzzle piece that would not fit (perseveration; d=0.50; 9% change), and insistence on completing the unsolvable puzzle (d=0.91; 10% change). Results suggest sleep serves an important role in the way toddlers respond to challenging events in their daily lives. After losing daytime sleep, toddlers were less able to effectively engage in a difficult task and reverted to less mature self-regulation strategies, than when they were well-rested. Over time, chronically missed sleep may impair young children’s self-regulation abilities, resulting in risk for social-emotional, behavioral, and school problems. PMID:25394169

  1. Negative feedback regulation of Homer 1a on norepinephrine-dependent cardiac hypertrophy

    International Nuclear Information System (INIS)

    Chiarello, Carmelina; Bortoloso, Elena; Carpi, Andrea; Furlan, Sandra; Volpe, Pompeo

    2013-01-01

    Homers are scaffolding proteins that modulate diverse cell functions being able to assemble signalling complexes. In this study, the presence, sub-cellular distribution and function of Homer 1 was investigated. Homer 1a and Homer 1b/c are constitutively expressed in cardiac muscle of both mouse and rat and in HL-1 cells, a cardiac cell line. As judged by confocal immunofluorescence microscopy, Homer 1a displays sarcomeric and peri-nuclear localization. In cardiomyocytes and cultured HL-1 cells, the hypertrophic agonist norepinephrine (NE) induces α 1 -adrenergic specific Homer 1a over-expression, with a two-to-three-fold increase within 1 h, and no up-regulation of Homer 1b/c, as judged by Western blot and qPCR. In HL-1 cells, plasmid-driven over-expression of Homer 1a partially antagonizes activation of ERK phosphorylation and ANF up-regulation, two well-established, early markers of hypertrophy. At the morphometric level, NE-induced increase of cell size is likewise and partially counteracted by exogenous Homer 1a. Under the same experimental conditions, Homer 1b/c does not have any effect on ANF up-regulation nor on cell hypertrophy. Thus, Homer 1a up-regulation is associated to early stages of cardiac hypertrophy and appears to play a negative feedback regulation on molecular transducers of hypertrophy. -- Highlights: • Homer 1a is constitutively expressed in cardiac tissue. • In HL-1 cells, norepinephrine activates signaling pathways leading to hypertrophy. • Homer 1a up-regulation is an early event of norepinephrine-induced hypertrophy. • Homer 1a plays a negative feedback regulation modulating pathological hypertrophy. • Over-expression of Homer 1a per se does not induce hypertrophy

  2. Bicarbonate-regulated adenylyl cyclase (sAC) is a sensor that regulates pH-dependent V-ATPase recycling.

    Science.gov (United States)

    Pastor-Soler, Nuria; Beaulieu, Valerie; Litvin, Tatiana N; Da Silva, Nicolas; Chen, Yanqiu; Brown, Dennis; Buck, Jochen; Levin, Lonny R; Breton, Sylvie

    2003-12-05

    Modulation of environmental pH is critical for the function of many biological systems. However, the molecular identity of the pH sensor and its interaction with downstream effector proteins remain poorly understood. Using the male reproductive tract as a model system in which luminal acidification is critical for sperm maturation and storage, we now report a novel pathway for pH regulation linking the bicarbonate activated soluble adenylyl cyclase (sAC) to the vacuolar H+ATPase (V-ATPase). Clear cells of the epididymis and vas deferens contain abundant V-ATPase in their apical pole and are responsible for acidifying the lumen. Proton secretion is regulated via active recycling of V-ATPase. Here we demonstrate that this recycling is regulated by luminal pH and bicarbonate. sAC is highly expressed in clear cells, and apical membrane accumulation of V-ATPase is triggered by a sAC-dependent rise in cAMP in response to alkaline luminal pH. As sAC is expressed in other acid/base transporting epithelia, including kidney and choroid plexus, this cAMP-dependent signal transduction pathway may be a widespread mechanism that allows cells to sense and modulate extracellular pH.

  3. WhiB6 is required for the secretion-dependent regulation of ESX-1 substrates in pathogenic mycobacteria.

    KAUST Repository

    Abdallah, Abdallah

    2018-04-09

    The mycobacterial type VII secretion system ESX-1 is responsible for the secretion of a number of proteins that play important roles during host infection. The regulation of the expression of secreted proteins is often essential to establish successful infection. Using transcriptome sequencing, we found that the abrogation of ESX-1 function in Mycobacterium marinum leads to a pronounced increase in gene expression levels of the espA operon during the infection of macrophages, suggesting an important role in ESX-1-mediated virulence during the early phase of infection. In addition, the disruption of ESX-1-mediated protein secretion also leads to a specific down-regulation of the ESX-1 substrates, but not of the structural components of this system, during growth in culture medium. This effect is observed in both M. marinum and M. tuberculosis. We established that down-regulation of ESX-1 substrates is the result of a regulatory process that is influenced by the putative transcriptional regulator whib6, which is located adjacent to the esx-1 locus. In addition, the overexpression of the ESX-1-associated PE35/PPE68 protein pair resulted in a significantly increased secretion of the ESX-1 substrate EsxA, demonstrating a functional link between these proteins. Taken together, these data show that WhiB6 is required for the secretion-dependent regulation of ESX-1 substrates and that ESX-1 substrates are regulated independently from the structural components, both during infection and as a result of active secretion.

  4. WhiB6 is required for the secretion-dependent regulation of ESX-1 substrates in pathogenic mycobacteria.

    KAUST Repository

    Abdallah, Abdallah; Weerdenburg, Eveline; Guan, Qingtian; Ummels, Roy; Borggreve, S; Adroub, Sabir; Malas, Tareq; Naeem, Raeece; Zhang, Huoming; Otto, Thomas; Bitter, Wilbert; Pain, Arnab

    2018-01-01

    The mycobacterial type VII secretion system ESX-1 is responsible for the secretion of a number of proteins that play important roles during host infection. The regulation of the expression of secreted proteins is often essential to establish successful infection. Using transcriptome sequencing, we found that the abrogation of ESX-1 function in Mycobacterium marinum leads to a pronounced increase in gene expression levels of the espA operon during the infection of macrophages, suggesting an important role in ESX-1-mediated virulence during the early phase of infection. In addition, the disruption of ESX-1-mediated protein secretion also leads to a specific down-regulation of the ESX-1 substrates, but not of the structural components of this system, during growth in culture medium. This effect is observed in both M. marinum and M. tuberculosis. We established that down-regulation of ESX-1 substrates is the result of a regulatory process that is influenced by the putative transcriptional regulator whib6, which is located adjacent to the esx-1 locus. In addition, the overexpression of the ESX-1-associated PE35/PPE68 protein pair resulted in a significantly increased secretion of the ESX-1 substrate EsxA, demonstrating a functional link between these proteins. Taken together, these data show that WhiB6 is required for the secretion-dependent regulation of ESX-1 substrates and that ESX-1 substrates are regulated independently from the structural components, both during infection and as a result of active secretion.

  5. PRKDC mutations associated with immunodeficiency, granuloma, and autoimmune regulator-dependent autoimmunity

    NARCIS (Netherlands)

    A.-L. Mathieu (Anne-Laure); E. Verronese (Estelle); G.I. Rice (Gillian I.); F. Fouyssac (Fanny); Y. Bertrand (Yves); C. Picard (Capucine); M. Chansel (Marie); J.E. Walter (Jolan E.); L.D. Notarangelo (Luigi Daniele); M.J. Butte (Manish J.); K.C. Nadeau (Kari Christine); K. Csomos (Krisztian); D.J. Chen (David); K. Chen (Karin); A. Delgado (Ana); C. Rigal (Chantal); C. Bardin (Christine); C. Schuetz (Catharina); D. Moshous (Despina); H. Reumaux (Héloïse); F. Plenat (François); A. Phan (Alice); M.-T. Zabot (Marie-Thérèse); B. Balme (Brigitte); S. Viel (Sébastien); J. Bienvenu (Jacques); P. Cochat (Pierre); M. van der Burg (Mirjam); C. Caux (Christophe); E.H. Kemp (E. Helen); I. Rouvet (Isabelle); C. Malcus (Christophe); J.-F. Méritet (Jean-Francois); A. Lim (Annick); Y.J. Crow (Yanick J.); N. Fabien (Nicole); C. Ménétrier-Caux (Christine); J.-P. De Villartay (Jean-Pierre); T. Walzer (Thierry); A. Belot (Alexandre)

    2015-01-01

    textabstractBackground PRKDC encodes for DNA-dependent protein kinase catalytic subunit (DNA-PKcs), a kinase that forms part of a complex (DNA-dependent protein kinase [DNA-PK]) crucial for DNA double-strand break repair and V(D)J recombination. In mice DNA-PK also interacts with the transcription

  6. A LuxS-Dependent Cell-to-Cell Language Regulates Social Behavior and Development in Bacillus subtilis

    OpenAIRE

    Lombardía, Esteban; Rovetto, Adrián J.; Arabolaza, Ana L.; Grau, Roberto R.

    2006-01-01

    Cell-to-cell communication in bacteria is mediated by quorum-sensing systems (QSS) that produce chemical signal molecules called autoinducers (AI). In particular, LuxS/AI-2-dependent QSS has been proposed to act as a universal lexicon that mediates intra- and interspecific bacterial behavior. Here we report that the model organism Bacillus subtilis operates a luxS-dependent QSS that regulates its morphogenesis and social behavior. We demonstrated that B. subtilis luxS is a growth-phase-regula...

  7. Ly49Q, a member of the Ly49 family that is selectively expressed on myeloid lineage cells and involved in regulation of cytoskeletal architecture

    Science.gov (United States)

    Toyama-Sorimachi, Noriko; Tsujimura, Yusuke; Maruya, Mikako; Onoda, Atsuko; Kubota, Toshiyuki; Koyasu, Shigeo; Inaba, Kayo; Karasuyama, Hajime

    2004-01-01

    Here, we identified and characterized a Ly49 family member, designated as Ly49Q. The Ly49q gene encodes a 273-aa protein with an immunoreceptor tyrosine-based inhibitory motif (ITIM) at the N terminus of its cytoplasmic domain. We show that the ITIM of Ly49Q can recruit SHP-2 and SHP-1 in a tyrosine phosphorylation-dependent manner. In contrast to other known members of the Ly49 family, Ly49Q was found not to be expressed on NK1.1+ cells, but instead was detectable on virtually all Gr-1+ cells, such as myeloid precursors in bone marrow. Monocytes/macrophages also expressed low levels of Ly49Q, and the expression was enhanced by the treatment of cells with IFN-γ. Treatment of activated macrophages with anti-Ly49Q mAb induced rapid formation of polarized actin structures, showing filopodia-like structure on one side and lamellipodial-like structure on the other side. A panel of proteins became tyrosine-phosphorylated in myeloid cells when treated with the mAb. Induction of the phosphorylation depends on the ITIM of Ly49Q. Thus, Ly49Q has unique features different from other known Ly49 family members and appears to be involved in regulation of cytoskeletal architecture of macrophages through ITIM-mediated signaling. PMID:14732700

  8. p120-catenin differentially regulates cell migration by Rho-dependent intracellular and secreted signals

    DEFF Research Database (Denmark)

    Epifano, Carolina; Megias, Diego; Perez-Moreno, Mirna

    2014-01-01

    The adherens junction protein p120-catenin is implicated in the regulation of cadherin stability, cell migration and inflammatory responses in mammalian epithelial tissues. How these events are coordinated to promote wound repair is not understood. We show that p120 catenin regulates the intrinsic...... migratory properties of primary mouse keratinocytes, but also influences the migratory behavior of neighboring cells by secreted signals. These events are rooted in the ability of p120-catenin to regulate RhoA GTPase activity, which leads to a two-tiered control of cell migration. One restrains cell...... motility via an increase in actin stress fibers, reduction in integrin turnover and an increase in the robustness of focal adhesions. The other is coupled to the secretion of inflammatory cytokines including interleukin-24, which causally enhances randomized cell movements. Taken together, our results...

  9. Quorum Sensing Regulation of Adhesion in Serratia Marcescens MG1 is surface dependent

    DEFF Research Database (Denmark)

    Labbate, M.; Zhu, H.; Thung, L.

    2007-01-01

    in a non-QS-controlled fashion. Therefore, the expression of these two genes appears to be cocontrolled by regulators other than the QS system for mediation of attachment to HCE cells. We also found that QS in S. marcescens regulates other potential cell surface adhesins, including exopolysaccharide...... and the outer membrane protein OmpX. We concluded that S. marcescens MG1 utilizes different regulatory systems and adhesins in attachment to biotic and abiotic surfaces and that QS is a main regulatory pathway in adhesion to an abiotic surface but not in adhesion to a biotic surface....

  10. Palmitoylation-dependent CDKL5–PSD-95 interaction regulates synaptic targeting of CDKL5 and dendritic spine development

    OpenAIRE

    Zhu, Yong-Chuan; Li, Dan; Wang, Lu; Lu, Bin; Zheng, Jing; Zhao, Shi-Lin; Zeng, Rong; Xiong, Zhi-Qi

    2013-01-01

    The X-linked gene cyclin-dependent kinase-like 5 (CDKL5) is mutated in severe neurodevelopmental disorders, including some forms of atypical Rett syndrome, but the function and regulation of CDKL5 protein in neurons remain to be elucidated. Here, we show that CDKL5 binds to the scaffolding protein postsynaptic density (PSD)-95, and that this binding promotes the targeting of CDKL5 to excitatory synapses. Interestingly, this binding is not constitutive, but governed by palmitate cycling on PSD...

  11. Self-Esteem, Relationship Threat, and Dependency Regulation: Independent Replication of Murray, Rose, Bellavia, Holmes, and Kusche (2002) Study 3

    OpenAIRE

    Stanton, Sarah; Moroz, Sarah; Balzarini, Rhonda; Dobson, Kiersten; Hahn, Christian; Kohut, Taylor; Campbell, Lorne

    2017-01-01

    Across three studies, Murray et al. (2002) found that low self-esteem individuals responded in a negative manner compared to those high in self-esteem in the face of relationship threat, perceiving their partners and relationships less positively. This was the first empirical support for the hypothesized dynamics of a dependency regulation perspective, and has had a significant impact on the field of relationship science. In the present research, we sought to reproduce the methods and procedu...

  12. Evaluating the efficacy of Regulated 12-Session Matrix Model in reducing susceptibility in methamphetamine-dependent individuals

    Directory of Open Access Journals (Sweden)

    Zahra Amiri

    2016-02-01

    Full Text Available Methamphetamine (abuse have gained popularity among youth and is increasingly become a part of mainstream culture. Methamphetamine(abuse is dangerous because of its wide range adverse outcomes and hazardous sustaining side effects. Its dependence is hardly withdrawn by routine therapeutic methods. This study is devoted to evaluate the efficacy of Regulated 12-Session Matrix Model in outpatient methamphetamine-dependent individuals. 24 individuals were chosen according to inclusion/exclusion criteria of the study and randomly assigned to equal experimental (age range 19-41; mean age: 46.9 and control groups (age range: 21-42; mean age: 27.8. Experimental group members partook Regulated 12-Session Matrix Model once a week in 12 consecutive weeks, while control group members remained at waitlist. Independent t-test in 12th week showed that experimental group had lower methamphetamine use, comparing to control group (p<.05.Phillai’s Trace, Wilk’s Lambda, HotellingLawley's trace, and Roy's largest root showed that there are significant association between experimental and control groups in reduction of methamphetamine-use lapse (p<.05.Within-subject F ratio revealed that “methamphetamine use” was significantly reduced in experimental group after clinical intervention (p<.001. Findings of the study indicate the efficacy of Regulated 12-Session Matrix Model in craving management and control as well as reduction of lapse and substance (abuse in methamphetamine-dependent patients. It appears that the Regulated 12-Session Matrix Model would be a new reliable solution to treat methamphetamine-dependence in Iran and other alike cultural and social atmospheres. Limitations and future implications are discussed.

  13. 3-Phosphoinositide-dependent PDK1 negatively regulates transforming growth factor-beta-induced signaling in a kinase-dependent manner through physical interaction with Smad proteins.

    Science.gov (United States)

    Seong, Hyun-A; Jung, Haiyoung; Kim, Kyong-Tai; Ha, Hyunjung

    2007-04-20

    We have reported previously that PDK1 physically interacts with STRAP, a transforming growth factor-beta (TGF-beta) receptor-interacting protein, and enhances STRAP-induced inhibition of TGF-beta signaling. In this study we show that PDK1 coimmunoprecipitates with Smad proteins, including Smad2, Smad3, Smad4, and Smad7, and that this association is mediated by the pleckstrin homology domain of PDK1. The association between PDK1 and Smad proteins is increased by insulin treatment but decreased by TGF-beta treatment. Analysis of the interacting proteins shows that Smad proteins enhance PDK1 kinase activity by removing 14-3-3, a negative regulator of PDK1, from the PDK1-14-3-3 complex. Knockdown of endogenous Smad proteins, including Smad3 and Smad7, by transfection with small interfering RNA produced the opposite trend and decreased PDK1 activity, protein kinase B/Akt phosphorylation, and Bad phosphorylation. Moreover, coexpression of Smad proteins and wild-type PDK1 inhibits TGF-beta-induced transcription, as well as TGF-beta-mediated biological functions, such as apoptosis and cell growth arrest. Inhibition was dose-dependent on PDK1, but no inhibition was observed in the presence of an inactive kinase-dead PDK1 mutant. In addition, confocal microscopy showed that wild-type PDK1 prevents translocation of Smad3 and Smad4 from the cytoplasm to the nucleus, as well as the redistribution of Smad7 from the nucleus to the cytoplasm in response to TGF-beta. Taken together, our results suggest that PDK1 negatively regulates TGF-beta-mediated signaling in a PDK1 kinase-dependent manner via a direct physical interaction with Smad proteins and that Smad proteins can act as potential positive regulators of PDK1.

  14. Regulation of spike timing-dependent plasticity of olfactory inputs in mitral cells in the rat olfactory bulb.

    Directory of Open Access Journals (Sweden)

    Teng-Fei Ma

    Full Text Available The recent history of activity input onto granule cells (GCs in the main olfactory bulb can affect the strength of lateral inhibition, which functions to generate contrast enhancement. However, at the plasticity level, it is unknown whether and how the prior modification of lateral inhibition modulates the subsequent induction of long-lasting changes of the excitatory olfactory nerve (ON inputs to mitral cells (MCs. Here we found that the repetitive stimulation of two distinct excitatory inputs to the GCs induced a persistent modification of lateral inhibition in MCs in opposing directions. This bidirectional modification of inhibitory inputs differentially regulated the subsequent synaptic plasticity of the excitatory ON inputs to the MCs, which was induced by the repetitive pairing of excitatory postsynaptic potentials (EPSPs with postsynaptic bursts. The regulation of spike timing-dependent plasticity (STDP was achieved by the regulation of the inter-spike-interval (ISI of the postsynaptic bursts. This novel form of inhibition-dependent regulation of plasticity may contribute to the encoding or processing of olfactory information in the olfactory bulb.

  15. Model of cap-dependent translation initiation in sea urchin: a step towards the eukaryotic translation regulation network.

    Science.gov (United States)

    Bellé, Robert; Prigent, Sylvain; Siegel, Anne; Cormier, Patrick

    2010-03-01

    The large and rapid increase in the rate of protein synthesis following fertilization of the sea urchin egg has long been a paradigm of translational control, an important component of the regulation of gene expression in cells. This translational up-regulation is linked to physiological changes that occur upon fertilization and is necessary for entry into first cell division cycle. Accumulated knowledge on cap-dependent initiation of translation makes it suited and timely to start integrating the data into a system view of biological functions. Using a programming environment for system biology coupled with model validation (named Biocham), we have built an integrative model for cap-dependent initiation of translation. The model is described by abstract rules. It contains 51 reactions involved in 74 molecular complexes. The model proved to be coherent with existing knowledge by using queries based on computational tree logic (CTL) as well as Boolean simulations. The model could simulate the change in translation occurring at fertilization in the sea urchin model. It could also be coupled with an existing model designed for cell-cycle control. Therefore, the cap-dependent translation initiation model can be considered a first step towards the eukaryotic translation regulation network.

  16. PPAR-alpha dependent regulation of vanin-1 mediates hepatic lipid metabolism

    NARCIS (Netherlands)

    Diepen, van J.A.; Jansen, P.A.; Ballak, D.B.; Hijmans, A.; Hooiveld, G.J.E.J.; Rommelaere, S.; Kersten, A.H.; Stienstra, R.

    2014-01-01

    Background & Aims Peroxisome proliferator-activated receptor alpha (PPARa) is a key regulator of hepatic fat oxidation that serves as an energy source during starvation. Vanin-1 has been described as a putative PPARa target gene in liver, but its function in hepatic lipid metabolism is unknown.

  17. Apoptosis in rat gastric antrum: Evidence that regulation by food intake depends on nitric oxide synthase

    DEFF Research Database (Denmark)

    Cao, Bao-Hong; Mortensen, Kirsten; Tornehave, Ditte

    2000-01-01

    NOS was present in somatostatin cells, in nonendocrine cells predominating in the surface and pit epithelium, and in rare nerve fibers. Endothelial cell NOS was present in vessels, whereas the inducible isoform was barely detectable. Thus, endogenous NOS isoforms participate in regulating antropyloric...

  18. Hippocampal Regulation of Context-Dependent Neuronal Activity in the Lateral Amygdala

    Science.gov (United States)

    Maren, Stephen; Hobin, Jennifer A.

    2007-01-01

    Pavlovian fear conditioning is a robust and enduring form of emotional learning that provides an ideal model system for studying contextual regulation of memory retrieval. After extinction the expression of fear conditional responses (CRs) is context-specific: A conditional stimulus (CS) elicits greater conditional responding outside compared with…

  19. CRP-dependent positive autoregulation and proteolytic degradation regulate competence activator Sxy of Escherichia coli

    DEFF Research Database (Denmark)

    Jaskólska, Milena; Gerdes, Kenn

    2015-01-01

    is positively autoregulated at the level of transcription by a mechanism that requires cAMP receptor protein (CRP), cyclic AMP (cAMP) and a CRP-S site in the sxy promoter. Similarly, we found no evidence that Sxy expression in E. coli was regulated at the translational level. However, our analysis revealed...

  20. CD1-dependent regulation of chronic central nervous system inflammation in experimental autoimmune encephalomyelitis

    DEFF Research Database (Denmark)

    Teige, Anna; Teige, Ingrid; Lavasani, Shahram

    2004-01-01

    (s). When immunized with CFA before T cell transfer, the CD1-/- mice again developed an augmented EAE compared with CD1+/+ mice. We suggest that CD1 exerts its function during CFA-mediated activation, regulating development of EAE both through enhancing TGF-beta1 production and through limiting autoreactive...

  1. PKCζ regulates Notch receptor routing and activity in a Notch signaling-dependent manner

    NARCIS (Netherlands)

    Sjöqvist, M.; Antfolk, D.; Ferraris, S.; Rraklli, V.; Haga, C.; Antila, C.; Mutvei, A.; Imanishi, S.Y.; Holmberg, J.; Jin, S.; Eriksson, J.E.; Lendahl, U.; Sahlgren, C.M.

    Activation of Notch signaling requires intracellular routing of the receptor, but the mechanisms controlling the distinct steps in the routing process is poorly understood. We identify PKCζ as a key regulator of Notch receptor intracellular routing. When PKCζ was inhibited in the developing chick

  2. AMPK governs lineage specification through Tfeb-dependent regulation of lysosomes.

    Science.gov (United States)

    Young, Nathan P; Kamireddy, Anwesh; Van Nostrand, Jeanine L; Eichner, Lillian J; Shokhirev, Maxim Nikolaievich; Dayn, Yelena; Shaw, Reuben J

    2016-03-01

    Faithful execution of developmental programs relies on the acquisition of unique cell identities from pluripotent progenitors, a process governed by combinatorial inputs from numerous signaling cascades that ultimately dictate lineage-specific transcriptional outputs. Despite growing evidence that metabolism is integrated with many molecular networks, how pathways that control energy homeostasis may affect cell fate decisions is largely unknown. Here, we show that AMP-activated protein kinase (AMPK), a central metabolic regulator, plays critical roles in lineage specification. Although AMPK-deficient embryonic stem cells (ESCs) were normal in the pluripotent state, these cells displayed profound defects upon differentiation, failing to generate chimeric embryos and preferentially adopting an ectodermal fate at the expense of the endoderm during embryoid body (EB) formation. AMPK(-/-) EBs exhibited reduced levels of Tfeb, a master transcriptional regulator of lysosomes, leading to diminished endolysosomal function. Remarkably, genetic loss of Tfeb also yielded endodermal defects, while AMPK-null ESCs overexpressing this transcription factor normalized their differential potential, revealing an intimate connection between Tfeb/lysosomes and germ layer specification. The compromised endolysosomal system resulting from AMPK or Tfeb inactivation blunted Wnt signaling, while up-regulating this pathway restored expression of endodermal markers. Collectively, these results uncover the AMPK pathway as a novel regulator of cell fate determination during differentiation. © 2016 Young et al.; Published by Cold Spring Harbor Laboratory Press.

  3. Transforming growth factor beta-activated kinase 1 (TAK1)-dependent checkpoint in the survival of dendritic cells promotes immune homeostasis and function.

    Science.gov (United States)

    Wang, Yanyan; Huang, Gonghua; Vogel, Peter; Neale, Geoffrey; Reizis, Boris; Chi, Hongbo

    2012-02-07

    Homeostatic control of dendritic cell (DC) survival is crucial for adaptive immunity, but the molecular mechanism is not well defined. Moreover, how DCs influence immune homeostasis under steady state remains unclear. Combining DC-specific and -inducible deletion systems, we report that transforming growth factor beta-activated kinase 1 (TAK1) is an essential regulator of DC survival and immune system homeostasis and function. Deficiency of TAK1 in CD11c(+) cells induced markedly elevated apoptosis, leading to the depletion of DC populations, especially the CD8(+) and CD103(+) DC subsets in lymphoid and nonlymphoid tissues, respectively. TAK1 also contributed to DC development by promoting the generation of DC precursors. Prosurvival signals from Toll-like receptors, CD40 and receptor activator of nuclear factor-κB (RANK) are integrated by TAK1 in DCs, which in turn mediated activation of downstream NF-κB and AKT-Foxo pathways and established a gene-expression program. TAK1 deficiency in DCs caused a myeloid proliferative disorder characterized by expansion of neutrophils and inflammatory monocytes, disrupted T-cell homeostasis, and prevented effective T-cell priming and generation of regulatory T cells. Moreover, TAK1 signaling in DCs was required to prevent myeloid proliferation even in the absence of lymphocytes, indicating a previously unappreciated regulatory mechanism of DC-mediated control of myeloid cell-dependent inflammation. Therefore, TAK1 orchestrates a prosurvival checkpoint in DCs that affects the homeostasis and function of the immune system.

  4. Position dependence of the rous sarcoma virus negative regulator of splicing element reflects proximity to a 5' splice site

    International Nuclear Information System (INIS)

    Wang Yuedi; McNally, Mark T.

    2003-01-01

    Rous sarcoma virus (RSV) requires incomplete splicing of its viral transcripts to maintain efficient replication. A splicing inhibitor element, the negative regulator of splicing (NRS), is located near the 5' end of the RNA but the significance of this positioning is not known. In a heterologous intron the NRS functions optimally when positioned close to the authentic 5' splice site. This observation led us to investigate the basis of the position dependence. Four explanations were put forth and stressed the role of three major elements involved in splicing, the 3' splice site, the 5' splice site, and the 5' end cap structure. NRS function was unrelated to its position relative to the 3' splice site or the cap structure and appeared to depend on its position relative to the authentic 5' splice site. We conclude that position dependence may reflect distance constraints necessary for competition of the NRS with the authentic 5' splice site for pairing with the 3' splice sites

  5. Activity-dependent self-regulation of viscous length scales in biological systems

    Science.gov (United States)

    Nandi, Saroj Kumar

    2018-05-01

    The cellular cortex, which is a highly viscous thin cytoplasmic layer just below the cell membrane, controls the cell's mechanical properties, which can be characterized by a hydrodynamic length scale ℓ . Cells actively regulate ℓ via the activity of force-generating molecules, such as myosin II. Here we develop a general theory for such systems through a coarse-grained hydrodynamic approach including activity in the static description of the system providing an experimentally accessible parameter and elucidate the detailed mechanism of how a living system can actively self-regulate its hydrodynamic length scale, controlling the rigidity of the system. Remarkably, we find that ℓ , as a function of activity, behaves universally and roughly inversely proportional to the activity of the system. Our theory rationalizes a number of experimental findings on diverse systems, and comparison of our theory with existing experimental data shows good agreement.

  6. BAD-Dependent Regulation of Fuel Metabolism and KATP Channel Activity Confers Resistance to Epileptic Seizures

    OpenAIRE

    Giménez-Cassina, Alfredo; Martínez-François, Juan Ramón; Fisher, Jill K.; Szlyk, Benjamin; Polak, Klaudia; Wiwczar, Jessica; Tanner, Geoffrey R.; Lutas, Andrew; Yellen, Gary; Danial, Nika N.

    2012-01-01

    Neuronal excitation can be substantially modulated by alterations in metabolism, as evident from the anticonvulsant effect of diets that reduce glucose utilization and promote ketone body metabolism. We provide genetic evidence that BAD, a protein with dual functions in apoptosis and glucose metabolism, imparts reciprocal effects on metabolism of glucose and ketone bodies in brain cells. These effects involve phospho-regulation of BAD and are independent of its apoptotic function. BAD modific...

  7. Rictor regulates FBXW7-dependent c-Myc and cyclin E degradation in colorectal cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Zheng [Markey Cancer Center, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, 1838 Guangzhou Dadao Bei, Guangzhou 510515 (China); Zhou, Yuning [Markey Cancer Center, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Evers, B. Mark [Markey Cancer Center, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Department of Surgery, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Wang, Qingding, E-mail: qingding.wang@uky.edu [Markey Cancer Center, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States); Department of Surgery, The University of Kentucky, 800 Rose Street, Lexington, KY 40536 (United States)

    2012-02-10

    Highlights: Black-Right-Pointing-Pointer Rictor associates with FBXW7 to form an E3 complex. Black-Right-Pointing-Pointer Knockdown of rictor decreases ubiquitination of c-Myc and cylin E. Black-Right-Pointing-Pointer Knockdown of rictor increases protein levels of c-Myc and cylin E. Black-Right-Pointing-Pointer Overexpression of rictor induces the degradation of c-Myc and cyclin E proteins. Black-Right-Pointing-Pointer Rictor regulation of c-Myc and cyclin E requires FBXW7. -- Abstract: Rictor (Rapamycin-insensitive companion of mTOR) forms a complex with mTOR and phosphorylates and activates Akt. Activation of Akt induces expression of c-Myc and cyclin E, which are overexpressed in colorectal cancer and play an important role in colorectal cancer cell proliferation. Here, we show that rictor associates with FBXW7 to form an E3 complex participating in the regulation of c-Myc and cyclin E degradation. The Rictor-FBXW7 complex is biochemically distinct from the previously reported mTORC2 and can be immunoprecipitated independently of mTORC2. Moreover, knocking down of rictor in serum-deprived colorectal cancer cells results in the decreased ubiquitination and increased protein levels of c-Myc and cyclin E while overexpression of rictor induces the degradation of c-Myc and cyclin E proteins. Genetic knockout of FBXW7 blunts the effects of rictor, suggesting that rictor regulation of c-Myc and cyclin E requires FBXW7. Our findings identify rictor as an important component of FBXW7 E3 ligase complex participating in the regulation of c-Myc and cyclin E protein ubiquitination and degradation. Importantly, our results suggest that elevated growth factor signaling may contribute to decrease rictor/FBXW7-mediated ubiquitination of c-Myc and cyclin E, thus leading to accumulation of cyclin E and c-Myc in colorectal cancer cells.

  8. Rictor regulates FBXW7-dependent c-Myc and cyclin E degradation in colorectal cancer cells

    International Nuclear Information System (INIS)

    Guo, Zheng; Zhou, Yuning; Evers, B. Mark; Wang, Qingding

    2012-01-01

    Highlights: ► Rictor associates with FBXW7 to form an E3 complex. ► Knockdown of rictor decreases ubiquitination of c-Myc and cylin E. ► Knockdown of rictor increases protein levels of c-Myc and cylin E. ► Overexpression of rictor induces the degradation of c-Myc and cyclin E proteins. ► Rictor regulation of c-Myc and cyclin E requires FBXW7. -- Abstract: Rictor (Rapamycin-insensitive companion of mTOR) forms a complex with mTOR and phosphorylates and activates Akt. Activation of Akt induces expression of c-Myc and cyclin E, which are overexpressed in colorectal cancer and play an important role in colorectal cancer cell proliferation. Here, we show that rictor associates with FBXW7 to form an E3 complex participating in the regulation of c-Myc and cyclin E degradation. The Rictor–FBXW7 complex is biochemically distinct from the previously reported mTORC2 and can be immunoprecipitated independently of mTORC2. Moreover, knocking down of rictor in serum-deprived colorectal cancer cells results in the decreased ubiquitination and increased protein levels of c-Myc and cyclin E while overexpression of rictor induces the degradation of c-Myc and cyclin E proteins. Genetic knockout of FBXW7 blunts the effects of rictor, suggesting that rictor regulation of c-Myc and cyclin E requires FBXW7. Our findings identify rictor as an important component of FBXW7 E3 ligase complex participating in the regulation of c-Myc and cyclin E protein ubiquitination and degradation. Importantly, our results suggest that elevated growth factor signaling may contribute to decrease rictor/FBXW7-mediated ubiquitination of c-Myc and cyclin E, thus leading to accumulation of cyclin E and c-Myc in colorectal cancer cells.

  9. Azospirillum brasilense Chemotaxis Depends on Two Signaling Pathways Regulating Distinct Motility Parameters.

    Science.gov (United States)

    Mukherjee, Tanmoy; Kumar, Dhivya; Burriss, Nathan; Xie, Zhihong; Alexandre, Gladys

    2016-06-15

    The genomes of most motile bacteria encode two or more chemotaxis (Che) systems, but their functions have been characterized in only a few model systems. Azospirillum brasilense is a motile soil alphaproteobacterium able to colonize the rhizosphere of cereals. In response to an attractant, motile A. brasilense cells transiently increase swimming speed and suppress reversals. The Che1 chemotaxis pathway was previously shown to regulate changes in the swimming speed, but it has a minor role in chemotaxis and root surface colonization. Here, we show that a second chemotaxis system, named Che4, regulates the probability of swimming reversals and is the major signaling pathway for chemotaxis and wheat root surface colonization. Experimental evidence indicates that Che1 and Che4 are functionally linked to coordinate changes in the swimming motility pattern in response to attractants. The effect of Che1 on swimming speed is shown to enhance the aerotactic response of A. brasilense in gradients, likely providing the cells with a competitive advantage in the rhizosphere. Together, the results illustrate a novel mechanism by which motile bacteria utilize two chemotaxis pathways regulating distinct motility parameters to alter movement in gradients and enhance the chemotactic advantage. Chemotaxis provides motile bacteria with a competitive advantage in the colonization of diverse niches and is a function enriched in rhizosphere bacterial communities, with most species possessing at least two chemotaxis systems. Here, we identify the mechanism by which cells may derive a significant chemotactic advantage using two chemotaxis pathways that ultimately regulate distinct motility parameters. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  10. Calmodulin and calcium differentially regulate the neuronal Nav1.1 voltage-dependent sodium channel

    Energy Technology Data Exchange (ETDEWEB)

    Gaudioso, Christelle; Carlier, Edmond; Youssouf, Fahamoe [INSERM U641, Institut Jean Roche, Marseille F-13344 (France); Universite de la Mediterranee, Faculte de Medecine Secteur Nord, IFR 11, Marseille F-13344 (France); Clare, Jeffrey J. [Eaton Pharma Consulting, Eaton Socon, Cambridgeshire PE19 8EF (United Kingdom); Debanne, Dominique [INSERM U641, Institut Jean Roche, Marseille F-13344 (France); Universite de la Mediterranee, Faculte de Medecine Secteur Nord, IFR 11, Marseille F-13344 (France); Alcaraz, Gisele, E-mail: gisele.alcaraz@univmed.fr [INSERM U641, Institut Jean Roche, Marseille F-13344 (France); Universite de la Mediterranee, Faculte de Medecine Secteur Nord, IFR 11, Marseille F-13344 (France)

    2011-07-29

    Highlights: {yields} Both Ca{sup ++}-Calmodulin (CaM) and Ca{sup ++}-free CaM bind to the C-terminal region of Nav1.1. {yields} Ca{sup ++} and CaM have both opposite and convergent effects on I{sub Nav1.1}. {yields} Ca{sup ++}-CaM modulates I{sub Nav1.1} amplitude. {yields} CaM hyperpolarizes the voltage-dependence of activation, and increases the inactivation rate. {yields} Ca{sup ++} alone antagonizes CaM for both effects, and depolarizes the voltage-dependence of inactivation. -- Abstract: Mutations in the neuronal Nav1.1 voltage-gated sodium channel are responsible for mild to severe epileptic syndromes. The ubiquitous calcium sensor calmodulin (CaM) bound to rat brain Nav1.1 and to the human Nav1.1 channel expressed by a stably transfected HEK-293 cell line. The C-terminal region of the channel, as a fusion protein or in the yeast two-hybrid system, interacted with CaM via a consensus C-terminal motif, the IQ domain. Patch clamp experiments on HEK1.1 cells showed that CaM overexpression increased peak current in a calcium-dependent way. CaM had no effect on the voltage-dependence of fast inactivation, and accelerated the inactivation kinetics. Elevating Ca{sup ++} depolarized the voltage-dependence of fast inactivation and slowed down the fast inactivation kinetics, and for high concentrations this effect competed with the acceleration induced by CaM alone. Similarly, the depolarizing action of calcium antagonized the hyperpolarizing shift of the voltage-dependence of activation due to CaM overexpression. Fluorescence spectroscopy measurements suggested that Ca{sup ++} could bind the Nav1.1 C-terminal region with micromolar affinity.

  11. The H3K27 demethylase, Utx, regulates adipogenesis in a differentiation stage-dependent manner.

    Directory of Open Access Journals (Sweden)

    Kazushige Ota

    Full Text Available Understanding the molecular mechanisms that drive adipogenesis is important in developing new treatments for obesity and diabetes. Epigenetic regulations determine the capacity of adipogenesis. In this study, we examined the role of a histone H3 lysine 27 demethylase, the ubiquitously transcribed tetratricopeptide repeat protein on the X chromosome (Utx, in the differentiation of mouse embryonic stem cells (mESCs to adipocytes. Using gene trapping, we examined Utx-deficient male mESCs to determine whether loss of Utx would enhance or inhibit the differentiation of mESCs to adipocytes. Utx-deficient mESCs showed diminished potential to differentiate to adipocytes compared to that of controls. In contrast, Utx-deficient preadipocytes showed enhanced differentiation to adipocytes. Microarray analyses indicated that the β-catenin/c-Myc signaling pathway was differentially regulated in Utx-deficient cells during adipocyte differentiation. Therefore, our data suggest that Utx governs adipogenesis by regulating c-Myc in a differentiation stage-specific manner and that targeting the Utx signaling pathway could be beneficial for the treatment of obesity, diabetes, and congenital utx-deficiency disorders.

  12. Axon-Axon Interactions Regulate Topographic Optic Tract Sorting via CYFIP2-Dependent WAVE Complex Function.

    Science.gov (United States)

    Cioni, Jean-Michel; Wong, Hovy Ho-Wai; Bressan, Dario; Kodama, Lay; Harris, William A; Holt, Christine E

    2018-03-07

    The axons of retinal ganglion cells (RGCs) are topographically sorted before they arrive at the optic tectum. This pre-target sorting, typical of axon tracts throughout the brain, is poorly understood. Here, we show that cytoplasmic FMR1-interacting proteins (CYFIPs) fulfill non-redundant functions in RGCs, with CYFIP1 mediating axon growth and CYFIP2 specifically involved in axon sorting. We find that CYFIP2 mediates homotypic and heterotypic contact-triggered fasciculation and repulsion responses between dorsal and ventral axons. CYFIP2 associates with transporting ribonucleoprotein particles in axons and regulates translation. Axon-axon contact stimulates CYFIP2 to move into growth cones where it joins the actin nucleating WAVE regulatory complex (WRC) in the periphery and regulates actin remodeling and filopodial dynamics. CYFIP2's function in axon sorting is mediated by its binding to the WRC but not its translational regulation. Together, these findings uncover CYFIP2 as a key regulatory link between axon-axon interactions, filopodial dynamics, and optic tract sorting. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  13. An experimental test of noise-dependent voice amplitude regulation in Cope's grey treefrog (Hyla chrysoscelis).

    Science.gov (United States)

    Love, Elliot K; Bee, Mark A

    2010-09-01

    One strategy for coping with the constraints on acoustic signal reception posed by ambient noise is to signal louder as noise levels increase. Termed the 'Lombard effect', this reflexive behaviour is widespread among birds and mammals and occurs with a diversity of signal types, leading to the hypothesis that voice amplitude regulation represents a general vertebrate mechanism for coping with environmental noise. Support for this evolutionary hypothesis, however, remains limited due to a lack of studies in taxa other than birds and mammals. Here, we report the results of an experimental test of the hypothesis that male grey treefrogs increase the amplitude of their advertisement calls in response to increasing levels of chorus-shaped noise. We recorded spontaneously produced calls in quiet and in the presence of noise broadcast at sound pressure levels ranging between 40 dB and 70 dB. While increasing noise levels induced predictable changes in call duration and rate, males did not regulate call amplitude. These results do not support the hypothesis that voice amplitude regulation is a generic vertebrate mechanism for coping with noise. We discuss the possibility that intense sexual selection and high levels of competition for mates in choruses place some frogs under strong selection to call consistently as loudly as possible.

  14. Melatonin regulates CRE-dependent gene transcription underlying osteoblast proliferation by activating Src and PKA in parallel.

    Science.gov (United States)

    Tao, Lin; Zhu, Yue

    2018-01-01

    Several studies have indicated a relationship between melatonin and idiopathic scoliosis, including our previous work which demonstrated that melatonin can inhibit osteoblast proliferation; however, the mechanism remains unclear. Here, we utilized a MTT assay to show that melatonin significantly reduces osteoblast proliferation in a concentration-and time-dependent manner. Through a combination of techniques, including real-time PCR, MTT assays, immunofluorescence, and luciferase assays, we confirmed that melatonin-induced changes in phosphorylated cAMP response element-binding protein (CREB) reduced transcriptional activity in a melatonin receptor-dependent manner. Surprisingly, treatment of osteoblasts with the mitogen-activated protein kinase/extracellular signal-regulated kinase kinase (MEK) inhibitor PD98059 up-regulated other cascades upstream of CREB. We next treated cells with PKA and Src inhibitors and observed that melatonin can also activate the protein kinase A (PKA) and Src pathways. To examine whether Src is upstream from the cAMP-PKA pathway, we measured cAMP levels in response to melatonin with and without a Src inhibitor (PP2) and found that PP2 had no additional effect. Therefore, the transcription-dependent mechanisms involved in CREB phosphorylation, along with melatonin, activated Src via a parallel signaling pathway that was separate from that of PKA. Finally, we transfected osteoblasts with lentiviral CREB short hairpin (sh) RNAs and found a decrease in the expression of proliferating cell nuclear antigen (PCNA) and osteoblast proliferation. These results suggest that CREB and PCNA are downstream targets of melatonin signaling, and that the down-regulation of CREB, which is regulated via PKA and Src pathways, contributes to the melatonin-induced inhibition of osteoblast proliferation.

  15. Stochastic seasonality and nonlinear density-dependent factors regulate population size in an African rodent

    DEFF Research Database (Denmark)

    Leirs, Herwig; Steneth, Nils Chr.; Nichols, James D.

    1997-01-01

    , but clear examples of both processes acting in the same population are rare(7,8). Key-factor analysis (regression of population changes on possible causal factors) and time-series analysis are often used to investigate the presence of density dependence, but such approaches may be biased and provide...... no information on actual demographic rates(9,10). Here we report on both density-dependent and density-independent effects in a murid rodent pest species, the multimammute rat Mastomys natalensis (Smith, 1834), using statistical capture-recapture models, Both effects occur simultaneously, but we also demonstrate...

  16. Intracellular pH regulation in unstimulated Calliphora salivary glands is Na+ dependent and requires V-ATPase activity.

    Science.gov (United States)

    Schewe, Bettina; Blenau, Wolfgang; Walz, Bernd

    2012-04-15

    Salivary gland cells of the blowfly Calliphora vicina have a vacuolar-type H(+)-ATPase (V-ATPase) that lies in their apical membrane and energizes the secretion of a KCl-rich primary saliva upon stimulation with serotonin (5-hydroxytryptamine). Whether and to what extent V-ATPase contributes to intracellular pH (pH(i)) regulation in unstimulated gland cells is unknown. We used the fluorescent dye BCECF to study intracellular pH(i) regulation microfluorometrically and show that: (1) under resting conditions, the application of Na(+)-free physiological saline induces an intracellular alkalinization attributable to the inhibition of the activity of a Na(+)-dependent glutamate transporter; (2) the maintenance of resting pH(i) is Na(+), Cl(-), concanamycin A and DIDS sensitive; (3) recovery from an intracellular acid load is Na(+) sensitive and requires V-ATPase activity; (4) the Na(+)/H(+) antiporter is not involved in pH(i) recovery after a NH(4)Cl prepulse; and (5) at least one Na(+)-dependent transporter and the V-ATPase maintain recovery from an intracellular acid load. Thus, under resting conditions, the V-ATPase and at least one Na(+)-dependent transporter maintain normal pH(i) values of pH 7.5. We have also detected the presence of a Na(+)-dependent glutamate transporter, which seems to act as an acid loader. Despite this not being a common pH(i)-regulating transporter, its activity affects steady-state pH(i) in C. vicina salivary gland cells.

  17. Sex-dependent regulation of hypoxic ventilation in mice and humans is mediated by erythropoietin

    DEFF Research Database (Denmark)

    Soliz, Jorge; Thomsen, Jonas Juhl; Soulage, Christophe

    2009-01-01

    increased in women. We conclude that Epo exerts a sex-dependent impact on hypoxic ventilation improving the response in female mice and in women that most probably involves sexual hormones. Our data provides an explanation as to why women are less susceptible to hypoxia-associated syndromes than men....

  18. DRF3 as a Cholesterol Dependent Regulator of Src in Prostate Cancer

    Science.gov (United States)

    2009-01-01

    blebbing ( Hannemann et al., 2008). Human DRF3 is not well studied, although analyses of the mouse homolog Drf3, and the close mouse paralog, Drf1/mDia1... Hannemann S, Madrid R, Stastna J, et al. The diaphanous related formin FHOD1 associates with ROCK1 and promotes Src-dependent plasma membrane blebbing

  19. Characterization of a calcium/calmodulin-dependent protein kinase homolog from maize roots showing light-regulated gravitropism

    Science.gov (United States)

    Lu, Y. T.; Hidaka, H.; Feldman, L. J.

    1996-01-01

    Roots of many species respond to gravity (gravitropism) and grow downward only if illuminated. This light-regulated root gravitropism is phytochrome-dependent, mediated by calcium, and inhibited by KN-93, a specific inhibitor of calcium/calmodulin-dependent protein kinase II (CaMK II). A cDNA encoding MCK1, a maize homolog of mammalian CaMK, has been isolated from roots of maize (Zea mays L.). The MCK1 gene is expressed in root tips, the site of perception for both light and gravity. Using the [35S]CaM gel-overlay assay we showed that calmodulin-binding activity of the MCK1 is abolished by 50 microM KN-93, but binding is not affected by 5 microM KN-93, paralleling physiological findings that light-regulated root gravitropism is inhibited by 50 microM KN-93, but not by 5 microM KN-93. KN-93 inhibits light-regulated gravitropism by interrupting transduction of the light signal, not light perception, suggesting that MCK1 may play a role in transducing light. This is the first report suggesting a physiological function for a CaMK homolog in light signal transduction.

  20. Genetic regulation by NLA and microRNA827 for maintaining nitrate-dependent phosphate homeostasis in arabidopsis.

    Science.gov (United States)

    Kant, Surya; Peng, Mingsheng; Rothstein, Steven J

    2011-03-01

    Plants need abundant nitrogen and phosphorus for higher yield. Improving plant genetics for higher nitrogen and phosphorus use efficiency would save potentially billions of dollars annually on fertilizers and reduce global environmental pollution. This will require knowledge of molecular regulators for maintaining homeostasis of these nutrients in plants. Previously, we reported that the NITROGEN LIMITATION ADAPTATION (NLA) gene is involved in adaptive responses to low-nitrogen conditions in Arabidopsis, where nla mutant plants display abrupt early senescence. To understand the molecular mechanisms underlying NLA function, two suppressors of the nla mutation were isolated that recover the nla mutant phenotype to wild type. Map-based cloning identified these suppressors as the phosphate (Pi) transport-related genes PHF1 and PHT1.1. In addition, NLA expression is shown to be regulated by the low-Pi induced microRNA miR827. Pi analysis revealed that the early senescence in nla mutant plants was due to Pi toxicity. These plants accumulated over five times the normal Pi content in shoots specifically under low nitrate and high Pi but not under high nitrate conditions. Also the Pi overaccumulator pho2 mutant shows Pi toxicity in a nitrate-dependent manner similar to the nla mutant. Further, the nitrate and Pi levels are shown to have an antagonistic crosstalk as displayed by their differential effects on flowering time. The results demonstrate that NLA and miR827 have pivotal roles in regulating Pi homeostasis in plants in a nitrate-dependent fashion.

  1. 4EGI-1 represses cap-dependent translation and regulates genome-wide translation in malignant pleural mesothelioma.

    Science.gov (United States)

    De, Arpita; Jacobson, Blake A; Peterson, Mark S; Jay-Dixon, Joe; Kratzke, Marian G; Sadiq, Ahad A; Patel, Manish R; Kratzke, Robert A

    2018-04-01

    Deregulation of cap-dependent translation has been implicated in the malignant transformation of numerous human tissues. 4EGI-1, a novel small-molecule inhibitor of cap-dependent translation, disrupts formation of the eukaryotic initiation factor 4F (eIF4F) complex. The effects of 4EGI-1-mediated inhibition of translation initiation in malignant pleural mesothelioma (MPM) were examined. 4EGI-1 preferentially inhibited cell viability and induced apoptosis in MPM cells compared to normal mesothelial (LP9) cells. This effect was associated with hypophosphorylation of 4E-binding protein 1 (4E-BP1) and decreased protein levels of the cancer-related genes, c-myc and osteopontin. 4EGI-1 showed enhanced cytotoxicity in combination with pemetrexed or gemcitabine. Translatome-wide polysome microarray analysis revealed a large cohort of genes that were translationally regulated upon treatment with 4EGI-1. The 4EGI-1-regulated translatome was negatively correlated to a previously published translatome regulated by eIF4E overexpression in human mammary epithelial cells, which is in agreement with the notion that 4EGI-1 inhibits the eIF4F complex. These data indicate that inhibition of the eIF4F complex by 4EGI-1 or similar translation inhibitors could be a strategy for treating mesothelioma. Genome wide translational profiling identified a large cohort of promising target genes that should be further evaluated for their potential significance in the treatment of MPM.

  2. Metal-dependent regulation of ATP7A and ATP7B in fibroblast cultures

    Directory of Open Access Journals (Sweden)

    Lenartowicz Malgorzata

    2016-08-01

    Full Text Available Deficiency of one of the copper transporters ATP7A and ATP7B leads to the rare X-linked disorder Menkes Disease (MD or the rare autosomal disorder Wilson disease (WD, respectively. In order to investigate whether the ATP7A and the ATP7B genes may be transcriptionally regulated, we measured the expression level of the two genes at various concentrations of iron, copper and insulin. Treating fibroblasts from controls or from individuals with MD or WD for 3 and10 days with iron chelators revealed that iron deficiency led to increased transcript levels of both ATP7A and ATP7B. Copper deficiency obtained by treatment with the copper chelator led to a downregulation of ATP7A in the control fibroblasts, but surprisingly not in the WD fibroblasts. In contrast, the addition of copper led to an increased expression of ATP7A, but a decreased expression of ATP7B. Thus, whereas similar regulation patterns for the two genes were observed in response to iron deficiency, different responses were observed after changes in the access to copper. Mosaic fibroblast cultures from female carriers of MD treated with copper or copper chelator for 6-8 weeks led to clonal selection. Cells that express the normal ATP7A allele had a selective growth advantage at high copper concentrations, whereas more surprisingly, cells that express the mutant ATP7A allele had a selective growth advantage at low copper concentrations. Thus, although the transcription of ATP7A is regulated by copper, clonal growth selection in mosaic cell cultures is affected by the level of copper. Female carriers of MD are rarely affected probably due to a skewed inactivation of the X-chromosome bearing the ATP7A mutation.

  3. CNC-bZIP protein Nrf1-dependent regulation of glucose-stimulated insulin secretion.

    Science.gov (United States)

    Zheng, Hongzhi; Fu, Jingqi; Xue, Peng; Zhao, Rui; Dong, Jian; Liu, Dianxin; Yamamoto, Masayuki; Tong, Qingchun; Teng, Weiping; Qu, Weidong; Zhang, Qiang; Andersen, Melvin E; Pi, Jingbo

    2015-04-01

    The inability of pancreatic β-cells to secrete sufficient insulin in response to glucose stimulation is a major contributing factor to the development of type 2 diabetes (T2D). We investigated both the in vitro and in vivo effects of deficiency of nuclear factor-erythroid 2-related factor 1 (Nrf1) in β-cells on β-cell function and glucose homeostasis. Silencing of Nrf1 in β-cells leads to a pre-T2D phenotype with disrupted glucose metabolism and impaired insulin secretion. Specifically, MIN6 β-cells with stable knockdown of Nrf1 (Nrf1-KD) and isolated islets from β-cell-specific Nrf1-knockout [Nrf1(b)-KO] mice displayed impaired glucose responsiveness, including elevated basal insulin release and decreased glucose-stimulated insulin secretion (GSIS). Nrf1(b)-KO mice exhibited severe fasting hyperinsulinemia, reduced GSIS, and glucose intolerance. Silencing of Nrf1 in MIN6 cells resulted in oxidative stress and altered glucose metabolism, with increases in both glucose uptake and aerobic glycolysis, which is associated with the elevated basal insulin release and reduced glucose responsiveness. The elevated glycolysis and reduced glucose responsiveness due to Nrf1 silencing likely result from altered expression of glucose metabolic enzymes, with induction of high-affinity hexokinase 1 and suppression of low-affinity glucokinase. Our study demonstrated a novel role of Nrf1 in regulating glucose metabolism and insulin secretion in β-cells and characterized Nrf1 as a key transcription factor that regulates the coupling of glycolysis and mitochondrial metabolism and GSIS. Nrf1 plays critical roles in regulating glucose metabolism, mitochondrial function, and insulin secretion, suggesting that Nrf1 may be a novel target to improve the function of insulin-secreting β-cells.

  4. Isoprenoid Pyrophosphate-Dependent Transcriptional Regulation of Carotenogenesis in Corynebacterium glutamicum

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    Petra Peters-Wendisch

    2017-04-01

    Full Text Available Corynebacterium glutamicum is a natural producer of the C50 carotenoid decaprenoxanthin. The crtEcg0722crtBIYEb operon comprises most of its genes for terpenoid biosynthesis. The MarR-type regulator encoded upstream and in divergent orientation of the carotenoid biosynthesis operon has not yet been characterized. This regulator, named CrtR in this study, is encoded in many actinobacterial genomes co-occurring with terpenoid biosynthesis genes. CrtR was shown to repress the crt operon of C. glutamicum since DNA microarray experiments revealed that transcript levels of crt operon genes were increased 10 to 70-fold in its absence. Transcriptional fusions of a promoter-less gfp gene with the crt operon and crtR promoters confirmed that CrtR represses its own gene and the crt operon. Gel mobility shift assays with purified His-tagged CrtR showed that CrtR binds to a region overlapping with the −10 and −35 promoter sequences of the crt operon. Isoprenoid pyrophosphates interfered with binding of CrtR to its target DNA, a so far unknown mechanism for regulation of carotenogenesis. The molecular details of protein-ligand interactions remain to be studied. Decaprenoxanthin synthesis by C. glutamicum wild type was enhanced 10 to 30-fold upon deletion of crtR and was decreased 5 to 6-fold as result of crtR overexpression. Moreover, deletion of crtR was shown as metabolic engineering strategy to improve production of native and non-native carotenoids including lycopene, β-carotene, C.p. 450 and sarcinaxanthin.

  5. Regulation of 2-5A Dependent RNase at the Level of its Phosphorylation

    Science.gov (United States)

    1991-06-26

    extract as follows: 25 ul wheat germ extract 10 ul H2O 1 ul RNasin ribonuclease inhibitor (40 u/ml) 7 ul ImM amino acid mixture 1 ul IM...diacylglycerol (DAG) 2. TPA 3. Indolactam Figure 6. Chemical structure of: 1. H-7 (A kinase inhibitor) 2. okadaic acid (A phosphatase inhibitor) Figure 7...elevating agents: Forskolin and Cholera toxin Figure 17. Down-regulation of 2-5A-depRNase by Okadaic 77 acid : A phosphatase inhibitor Figure 18

  6. Opioid regulation of mu receptor internalisation: relevance to the development of tolerance and dependence.

    Science.gov (United States)

    Lopez-Gimenez, Juan F; Milligan, Graeme

    2010-11-01

    Internalisation of the mu opioid receptor from the surface of cells is generally achieved by receptor occupancy with agonist ligands of high efficacy. However, in many situations the potent analgesic morphine fails to promote internalisation effectively and whether there is a direct link between this and the propensity for the sustained use of morphine to result in both tolerance and dependence has been studied intensely. Although frequently described as a partial agonist, this characteristic appears insufficient to explain the poor capacity of morphine to promote internalisation of the mu opioid receptor. Experiments performed using both transfected cell systems and ex vivo/in vivo models have provided evidence that when morphine can promote internalisation of the mu receptor there is a decrease in the development of tolerance and dependence. Although aspects of this model are controversial, such observations suggest a number of approaches to further enhance the use of morphine as an analgesic.

  7. Regulation of CCR7-dependent cell migration through?CCR7 homodimer formation

    OpenAIRE

    Kobayashi, Daichi; Endo, Masataka; Ochi, Hirotaka; Hojo, Hironobu; Miyasaka, Masayuki; Hayasaka, Haruko

    2017-01-01

    The chemokine receptor CCR7 contributes to various physiological and pathological processes including T cell maturation, T cell migration from the blood into secondary lymphoid tissues, and tumor cell metastasis to lymph nodes. Although a previous study suggested that the efficacy of CCR7 ligand-dependent T cell migration correlates with CCR7 homo- and heterodimer formation, the exact extent of contribution of the CCR7 dimerization remains unclear. Here, by inducing or disrupting CCR7 dimers,...

  8. EGFR-Dependent Regulation of Matrix-Independent Epithelial Cell Survival. Addendum

    Science.gov (United States)

    2007-04-01

    of the original proposal. The results obtained have identified key players that coordinate keratinocyte survival dependent on soluble growth factors...2004;6:203–8. 4. Duffey DC, Chen Z, Dong G, et al. Expression of a dominant-negative mutant inhibitor- nBa of nuclear fac- tor-nB in human head and neck...Attempts to treat such tumors with EGFR antagonists have met with remarkable initial successes , particularly when EGFR antagonists were used in

  9. A Gata2-Dependent Transcription Network Regulates Uterine Progesterone Responsiveness and Endometrial Function

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    Cory A. Rubel

    2016-10-01

    Full Text Available Altered progesterone responsiveness leads to female infertility and cancer, but underlying mechanisms remain unclear. Mice with uterine-specific ablation of GATA binding protein 2 (Gata2 are infertile, showing failures in embryo implantation, endometrial decidualization, and uninhibited estrogen signaling. Gata2 deficiency results in reduced progesterone receptor (PGR expression and attenuated progesterone signaling, as evidenced by genome-wide expression profiling and chromatin immunoprecipitation. GATA2 not only occupies at and promotes expression of the Pgr gene but also regulates downstream progesterone responsive genes in conjunction with the PGR. Additionally, Gata2 knockout uteri exhibit abnormal luminal epithelia with ectopic TRP63 expressing squamous cells and a cancer-related molecular profile in a progesterone-independent manner. Lastly, we found a conserved GATA2-PGR regulatory network in both human and mice based on gene signature and path analyses using gene expression profiles of human endometrial tissues. In conclusion, uterine Gata2 regulates a key regulatory network of gene expression for progesterone signaling at the early pregnancy stage.

  10. hCG-dependent regulation of angiogenic factors in human granulosa lutein cells.

    Science.gov (United States)

    Phan, B; Rakenius, A; Pietrowski, D; Bettendorf, H; Keck, C; Herr, D

    2006-07-01

    As prerequisite for development and maintenance of many diseases angiogenesis is of particular interest in medicine. Pathologic angiogenesis takes place in chronic arthritis, collagen diseases, arteriosclerosis, retinopathy associated with diabetes, and particularly in cancers. However, angiogenesis as a physiological process regularly occurs in the ovary. After ovulation the corpus luteum is formed by rapid vascularization of initially avascular granulosa lutein cell tissue. This process is regulated by gonadotropic hormones. In order to gain further insights in the regulatory mechanisms of angiogenesis in the ovary, we investigated these mechanisms in cell culture of human granulosa lutein cells. In particular, we determined the expression and production of several angiogenic factors including tissue inhibitor of matrix metalloproteinases-1 (TIMP-1), Leptin, connective tissue growth factor (CTGF), meningioma-associated complimentary DNA (Mac25), basic fibroblast growth factor (bFGF), and Midkine. In addition, we showed that human chorionic gonadotropin (hCG) has distinct effects on their expression and production. hCG enhances the expression and production of TIMP-1, whereas it downregulates the expression of CTGF and Mac25. Furthermore it decreases the expression of Leptin. Our results provide evidence that hCG determines growth and development of the corpus luteum by mediating angiogenic pathways in human granulosa lutein cells. Hence we describe a further approach to understand the regulation of angiogenesis in the ovary.

  11. Local 3D matrix microenvironment regulates cell migration through spatiotemporal dynamics of contractility-dependent adhesions

    Science.gov (United States)

    Doyle, Andrew D.; Carvajal, Nicole; Jin, Albert; Matsumoto, Kazue; Yamada, Kenneth M.

    2015-11-01

    The physical properties of two-dimensional (2D) extracellular matrices (ECMs) modulate cell adhesion dynamics and motility, but little is known about the roles of local microenvironmental differences in three-dimensional (3D) ECMs. Here we generate 3D collagen gels of varying matrix microarchitectures to characterize their regulation of 3D adhesion dynamics and cell migration. ECMs containing bundled fibrils demonstrate enhanced local adhesion-scale stiffness and increased adhesion stability through balanced ECM/adhesion coupling, whereas highly pliable reticular matrices promote adhesion retraction. 3D adhesion dynamics are locally regulated by ECM rigidity together with integrin/ECM association and myosin II contractility. Unlike 2D migration, abrogating contractility stalls 3D migration regardless of ECM pore size. We find force is not required for clustering of activated integrins on 3D native collagen fibrils. We propose that efficient 3D migration requires local balancing of contractility with ECM stiffness to stabilize adhesions, which facilitates the detachment of activated integrins from ECM fibrils.

  12. RUNX Family Participates in the Regulation of p53-Dependent DNA Damage Response

    Directory of Open Access Journals (Sweden)

    Toshinori Ozaki

    2013-01-01

    Full Text Available A proper DNA damage response (DDR, which monitors and maintains the genomic integrity, has been considered to be a critical barrier against genetic alterations to prevent tumor initiation and progression. The representative tumor suppressor p53 plays an important role in the regulation of DNA damage response. When cells receive DNA damage, p53 is quickly activated and induces cell cycle arrest and/or apoptotic cell death through transactivating its target genes implicated in the promotion of cell cycle arrest and/or apoptotic cell death such as p21WAF1, BAX, and PUMA. Accumulating evidence strongly suggests that DNA damage-mediated activation as well as induction of p53 is regulated by posttranslational modifications and also by protein-protein interaction. Loss of p53 activity confers growth advantage and ensures survival in cancer cells by inhibiting apoptotic response required for tumor suppression. RUNX family, which is composed of RUNX1, RUNX2, and RUNX3, is a sequence-specific transcription factor and is closely involved in a variety of cellular processes including development, differentiation, and/or tumorigenesis. In this review, we describe a background of p53 and a functional collaboration between p53 and RUNX family in response to DNA damage.

  13. Proteasome- and Ethanol-Dependent Regulation of HCV-Infection Pathogenesis

    Directory of Open Access Journals (Sweden)

    Natalia A. Osna

    2014-09-01

    Full Text Available This paper reviews the role of the catabolism of HCV and signaling proteins in HCV protection and the involvement of ethanol in HCV-proteasome interactions. HCV specifically infects hepatocytes, and intracellularly expressed HCV proteins generate oxidative stress, which is further exacerbated by heavy drinking. The proteasome is the principal proteolytic system in cells, and its activity is sensitive to the level of cellular oxidative stress. Not only host proteins, but some HCV proteins are degraded by the proteasome, which, in turn, controls HCV propagation and is crucial for the elimination of the virus. Ubiquitylation of HCV proteins usually leads to the prevention of HCV propagation, while accumulation of undegraded viral proteins in the nuclear compartment exacerbates infection pathogenesis. Proteasome activity also regulates both innate and adaptive immunity in HCV-infected cells. In addition, the proteasome/immunoproteasome is activated by interferons, which also induce “early” and “late” interferon-sensitive genes (ISGs with anti-viral properties. Cleaving viral proteins to peptides in professional immune antigen presenting cells and infected (“target” hepatocytes that express the MHC class I-antigenic peptide complex, the proteasome regulates the clearance of infected hepatocytes by the immune system. Alcohol exposure prevents peptide cleavage by generating metabolites that impair proteasome activity, thereby providing escape mechanisms that interfere with efficient viral clearance to promote the persistence of HCV-infection.

  14. Sensitivity to lysosome-dependent cell death is directly regulated by lysosomal cholesterol content.

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    Hanna Appelqvist

    Full Text Available Alterations in lipid homeostasis are implicated in several neurodegenerative diseases, although the mechanisms responsible are poorly understood. We evaluated the impact of cholesterol accumulation, induced by U18666A, quinacrine or mutations in the cholesterol transporting Niemann-Pick disease type C1 (NPC1 protein, on lysosomal stability and sensitivity to lysosome-mediated cell death. We found that neurons with lysosomal cholesterol accumulation were protected from oxidative stress-induced apoptosis. In addition, human fibroblasts with cholesterol-loaded lysosomes showed higher lysosomal membrane stability than controls. Previous studies have shown that cholesterol accumulation is accompanied by the storage of lipids such as sphingomyelin, glycosphingolipids and sphingosine and an up regulation of lysosomal associated membrane protein-2 (LAMP-2, which may also influence lysosomal stability. However, in this study the use of myriocin and LAMP deficient fibroblasts excluded these factors as responsible for the rescuing effect and instead suggested that primarily lysosomal cholesterol content determineD the cellular sensitivity to toxic insults. Further strengthening this concept, depletion of cholesterol using methyl-β-cyclodextrin or 25-hydroxycholesterol decreased the stability of lysosomes and cells became more prone to undergo apoptosis. In conclusion, cholesterol content regulated lysosomal membrane permeabilization and thereby influenced cell death sensitivity. Our data suggests that lysosomal cholesterol modulation might be used as a therapeutic strategy for conditions associated with accelerated or repressed apoptosis.

  15. ADAMTS9-Regulated Pericellular Matrix Dynamics Governs Focal Adhesion-Dependent Smooth Muscle Differentiation

    Directory of Open Access Journals (Sweden)

    Timothy J. Mead

    2018-04-01

    Full Text Available Summary: Focal adhesions anchor cells to extracellular matrix (ECM and direct assembly of a pre-stressed actin cytoskeleton. They act as a cellular sensor and regulator, linking ECM to the nucleus. Here, we identify proteolytic turnover of the anti-adhesive proteoglycan versican as a requirement for maintenance of smooth muscle cell (SMC focal adhesions. Using conditional deletion in mice, we show that ADAMTS9, a secreted metalloprotease, is required for myometrial activation during late gestation and for parturition. Through knockdown of ADAMTS9 in uterine SMC, and manipulation of pericellular versican via knockdown or proteolysis, we demonstrate that regulated pericellular matrix dynamics is essential for focal adhesion maintenance. By influencing focal adhesion formation, pericellular versican acts upstream of cytoskeletal assembly and SMC differentiation. Thus, pericellular versican proteolysis by ADAMTS9 balances pro- and anti-adhesive forces to maintain an SMC phenotype, providing a concrete example of the dynamic reciprocity of cells and their ECM. : Mead et al. identify a proteolytic mechanism that actively maintains a pericellular microenvironment conducive to uterine smooth muscle activation prior to parturition. They show that pericellular matrix proteolysis by the secreted metalloprotease ADAMTS9 is crucial for maintenance of focal adhesions in uterine smooth muscle cells, and its absence impairs parturition. Keywords: metalloprotease, extracellular matrix, smooth muscle, proteoglycan, myometrium, parturition, uterus, focal adhesion, proteolysis, interference reflection microscopy

  16. LKB1 Regulates Mitochondria-Dependent Presynaptic Calcium Clearance and Neurotransmitter Release Properties at Excitatory Synapses along Cortical Axons.

    Science.gov (United States)

    Kwon, Seok-Kyu; Sando, Richard; Lewis, Tommy L; Hirabayashi, Yusuke; Maximov, Anton; Polleux, Franck

    2016-07-01

    Individual synapses vary significantly in their neurotransmitter release properties, which underlie complex information processing in neural circuits. Presynaptic Ca2+ homeostasis plays a critical role in specifying neurotransmitter release properties, but the mechanisms regulating synapse-specific Ca2+ homeostasis in the mammalian brain are still poorly understood. Using electrophysiology and genetically encoded Ca2+ sensors targeted to the mitochondrial matrix or to presynaptic boutons of cortical pyramidal neurons, we demonstrate that the presence or absence of mitochondria at presynaptic boutons dictates neurotransmitter release properties through Mitochondrial Calcium Uniporter (MCU)-dependent Ca2+ clearance. We demonstrate that the serine/threonine kinase LKB1 regulates MCU expression, mitochondria-dependent Ca2+ clearance, and thereby, presynaptic release properties. Re-establishment of MCU-dependent mitochondrial Ca2+ uptake at glutamatergic synapses rescues the altered neurotransmitter release properties characterizing LKB1-null cortical axons. Our results provide novel insights into the cellular and molecular mechanisms whereby mitochondria control neurotransmitter release properties in a bouton-specific way through presynaptic Ca2+ clearance.

  17. Suppression of Mediator is regulated by Cdk8-dependent Grr1 turnover of the Med3 coactivator.

    Science.gov (United States)

    Gonzalez, Deyarina; Hamidi, Nurul; Del Sol, Ricardo; Benschop, Joris J; Nancy, Thomas; Li, Chao; Francis, Lewis; Tzouros, Manuel; Krijgsveld, Jeroen; Holstege, Frank C P; Conlan, R Steven

    2014-02-18

    Mediator, an evolutionary conserved large multisubunit protein complex with a central role in regulating RNA polymerase II-transcribed genes, serves as a molecular switchboard at the interface between DNA binding transcription factors and the general transcription machinery. Mediator subunits include the Cdk8 module, which has both positive and negative effects on activator-dependent transcription through the activity of the cyclin-dependent kinase Cdk8, and the tail module, which is required for positive and negative regulation of transcription, correct preinitiation complex formation in basal and activated transcription, and Mediator recruitment. Currently, the molecular mechanisms governing Mediator function remain largely undefined. Here we demonstrate an autoregulatory mechanism used by Mediator to repress transcription through the activity of distinct components of different modules. We show that the function of the tail module component Med3, which is required for transcription activation, is suppressed by the kinase activity of the Cdk8 module. Med3 interacts with, and is phosphorylated by, Cdk8; site-specific phosphorylation triggers interaction with and degradation by the Grr1 ubiquitin ligase, thereby preventing transcription activation. This active repression mechanism involving Grr1-dependent ubiquitination of Med3 offers a rationale for the substoichiometric levels of the tail module that are found in purified Mediator and the corresponding increase in tail components seen in cdk8 mutants.

  18. Endothelium derived nitric oxide synthase negatively regulates the PDGF-survivin pathway during flow-dependent vascular remodeling.

    Directory of Open Access Journals (Sweden)

    Jun Yu

    Full Text Available Chronic alterations in blood flow initiate structural changes in vessel lumen caliber to normalize shear stress. The loss of endothelial derived nitric oxide synthase (eNOS in mice promotes abnormal flow dependent vascular remodeling, thus uncoupling mechanotransduction from adaptive vascular remodeling. However, the mechanisms of how the loss of eNOS promotes abnormal remodeling are not known. Here we show that abnormal flow-dependent remodeling in eNOS knockout mice (eNOS (-/- is associated with activation of the platelet derived growth factor (PDGF signaling pathway leading to the induction of the inhibitor of apoptosis, survivin. Interfering with PDGF signaling or survivin function corrects the abnormal remodeling seen in eNOS (-/- mice. Moreover, nitric oxide (NO negatively regulates PDGF driven survivin expression and cellular proliferation in cultured vascular smooth muscle cells. Collectively, our data suggests that eNOS negatively regulates the PDGF-survivin axis to maintain proportional flow-dependent luminal remodeling and vascular quiescence.

  19. Chloroquine uptake, altered partitioning and the basis of drug resistance: evidence for chloride-dependent ionic regulation.

    Science.gov (United States)

    Martiney, J A; Ferrer, A S; Cerami, A; Dzekunov, S; Roepe, P

    1999-01-01

    The biochemical mechanism of chloroquine resistance in Plasmodium falciparum remains unknown. We postulated that chloroquine-resistant strains could alter ion fluxes that then indirectly control drug accumulation within the parasite by affecting pH and/or membrane potential ('altered partitioning mechanism'). Two principal intracellular pH-regulating systems in many cell types are the amiloride-sensitive Na+/H+ exchanger (NHE), and the sodium-independent, stilbene-sensitive Cl-/HCO3- antiporter (AE). We report that under physiological conditions (balanced CO2 and HCO3-) chloroquine uptake and susceptibility are not altered by amiloride analogues. We also do not detect a significant difference in NHE activity between chloroquine-sensitive and chloroquine-resistant strains via single cell photometry methods. AE activity is dependent on the intracellular and extracellular concentrations of Cl- and HCO3- ions. Chloroquine-resistant strains differentially respond to experimental modifications in chloride-dependent homeostasis, including growth, cytoplasmic pH and pH regulation. Chloroquine susceptibility is altered by stilbene DIDS only on chloroquine-resistant strains. Our results suggest that a Cl(-)-dependent system (perhaps AE) has a significant effect on the uptake of chloroquine by the infected erythrocyte, and that alterations of this biophysical parameter may be part of the mechanism of chloroquine resistance in P. falciparum.

  20. Synaptic convergence regulates synchronization-dependent spike transfer in feedforward neural networks.

    Science.gov (United States)

    Sailamul, Pachaya; Jang, Jaeson; Paik, Se-Bum

    2017-12-01

    Correlated neural activities such as synchronizations can significantly alter the characteristics of spike transfer between neural layers. However, it is not clear how this synchronization-dependent spike transfer can be affected by the structure of convergent feedforward wiring. To address this question, we implemented computer simulations of model neural networks: a source and a target layer connected with different types of convergent wiring rules. In the Gaussian-Gaussian (GG) model, both the connection probability and the strength are given as Gaussian distribution as a function of spatial distance. In the Uniform-Constant (UC) and Uniform-Exponential (UE) models, the connection probability density is a uniform constant within a certain range, but the connection strength is set as a constant value or an exponentially decaying function, respectively. Then we examined how the spike transfer function is modulated under these conditions, while static or synchronized input patterns were introduced to simulate different levels of feedforward spike synchronization. We observed that the synchronization-dependent modulation of the transfer function appeared noticeably different for each convergence condition. The modulation of the spike transfer function was largest in the UC model, and smallest in the UE model. Our analysis showed that this difference was induced by the different spike weight distributions that was generated from convergent synapses in each model. Our results suggest that, the structure of the feedforward convergence is a crucial factor for correlation-dependent spike control, thus must be considered important to understand the mechanism of information transfer in the brain.

  1. Novel Roles for the Insulin-Regulated Glucose Transporter-4 in Hippocampally Dependent Memory.

    Science.gov (United States)

    Pearson-Leary, Jiah; McNay, Ewan C

    2016-11-23

    The insulin-regulated glucose transporter-4 (GluT4) is critical for insulin- and contractile-mediated glucose uptake in skeletal muscle. GluT4 is also expressed in some hippocampal neurons, but its functional role in the brain is unclear. Several established molecular modulators of memory processing regulate hippocampal GluT4 trafficking and hippocampal memory formation is limited by both glucose metabolism and insulin signaling. Therefore, we hypothesized that hippocampal GluT4 might be involved in memory processes. Here, we show that, in male rats, hippocampal GluT4 translocates to the plasma membrane after memory training and that acute, selective intrahippocampal inhibition of GluT4-mediated glucose transport impaired memory acquisition, but not memory retrieval. Other studies have shown that prolonged systemic GluT4 blockade causes insulin resistance. Unexpectedly, we found that prolonged hippocampal blockade of glucose transport through GluT4-upregulated markers of hippocampal insulin signaling prevented task-associated depletion of hippocampal glucose and enhanced both working and short-term memory while also impairing long-term memory. These effects were accompanied by increased expression of hippocampal AMPA GluR1 subunits and the neuronal GluT3, but decreased expression of hippocampal brain-derived neurotrophic factor, consistent with impaired ability to form long-term memories. Our findings are the first to show the cognitive impact of brain GluT4 modulation. They identify GluT4 as a key regulator of hippocampal memory processing and also suggest differential regulation of GluT4 in the hippocampus from that in peripheral tissues. The role of insulin-regulated glucose transporter-4 (GluT4) in the brain is unclear. In the current study, we demonstrate that GluT4 is a critical component of hippocampal memory processes. Memory training increased hippocampal GluT4 translocation and memory acquisition was impaired by GluT4 blockade. Unexpectedly, whereas long

  2. Histone Methylation and microRNA-dependent Regulation of Epigenetic Activities in Neural Progenitor Self-Renewal and Differentiation.

    Science.gov (United States)

    Cacci, Emanuele; Negri, Rodolfo; Biagioni, Stefano; Lupo, Giuseppe

    2017-01-01

    Neural stem/progenitor cell (NSPC) self-renewal and differentiation in the developing and the adult brain are controlled by extra-cellular signals and by the inherent competence of NSPCs to produce appropriate responses. Stage-dependent responsiveness of NSPCs to extrinsic cues is orchestrated at the epigenetic level. Epigenetic mechanisms such as DNA methylation, histone modifications and non-coding RNA-mediated regulation control crucial aspects of NSPC development and function, and are also implicated in pathological conditions. While their roles in the regulation of stem cell fate have been largely explored in pluripotent stem cell models, the epigenetic signature of NSPCs is also key to determine their multipotency as well as their progressive bias towards specific differentiation outcomes. Here we review recent developments in this field, focusing on the roles of histone methylation marks and the protein complexes controlling their deposition in NSPCs of the developing cerebral cortex and the adult subventricular zone. In this context, we describe how bivalent promoters, carrying antagonistic epigenetic modifications, feature during multiple steps of neural development, from neural lineage specification to neuronal differentiation. Furthermore, we discuss the emerging cross-talk between epigenetic regulators and microRNAs, and how the interplay between these different layers of regulation can finely tune the expression of genes controlling NSPC maintenance and differentiation. In particular, we highlight recent advances in the identification of astrocyte-enriched microRNAs and their function in cell fate choices of NSPCs differentiating towards glial lineages.

  3. Effect of metabolic regulation on renal leakiness to dextran molecules in short-term insulin-dependent diabetics

    DEFF Research Database (Denmark)

    Parving, H H; Rutili, F; Granath, K

    1979-01-01

    Renal clearance of dextran of two ranges of molecular size and glomerular filtration rate (GFR, 51Cr-EDTA) were measured in seven short-term insulin-dependent diabetics (mean age 25 years). Measurements were carried out in the same patient during good and poor metabolic regulation (plasma glucose......, mean +/- SEM, 6.5 +/- 0.9 and 14.8 +/- 1.5 mmol/l, respectively). GFR was elevated in all patients during poor metabolic regulation (119 +/- 6 ml/min/1.73 m2, versus 99 +/- 2 ml/min/1.73 m2 during good control, p less than 0.01). The average renal clearance of dextran with molecular weights ranging...... from 25,000 to 35,000 and 35,000 to 45,000 increased during poor metabolic regulation from 14.8 +/- 0.8 to 19.8 +/- 1.8 ml/min/1.73 m2, and 5.2 +/- 0.3 to 6.8 +/- 0.6 ml/min/1.73 m2, respectively (p less than 0.05). The elevated GFR and renal dextran clearance found during poor metabolic regulation...

  4. Nutritional status-dependent endocannabinoid signalling regulates the integration of rat visceral information.

    Science.gov (United States)

    Khlaifia, Abdessattar; Matias, Isabelle; Cota, Daniela; Tell, Fabien

    2017-06-01

    Vagal sensory inputs transmit information from the viscera to brainstem neurones located in the nucleus tractus solitarii to set physiological parameters. These excitatory synapses exhibit a CB1 endocannabinoid-induced long-term depression (LTD) triggered by vagal fibre stimulation. We investigated the impact of nutritional status on long-term changes in this long-term synaptic plasticity. Food deprivation prevents LTD induction by disrupting CB1 receptor signalling. Short-term refeeding restores the capacity of vagal synapses to express LTD. Ghrelin and cholecystokinin, respectively released during fasting and refeeding, play a key role in the control of LTD via the activation of energy sensing pathways such as AMPK and the mTOR and ERK pathways. Communication form the viscera to the brain is essential to set physiological homoeostatic parameters but also to drive more complex behaviours such as mood, memory and emotional states. Here we investigated the impact of the nutritional status on long-term changes in excitatory synaptic transmission in the nucleus tractus solitarii, a neural hub integrating visceral signals. These excitatory synapses exhibit a CB1 endocannabinoid (eCB)-induced long-term depression (LTD) triggered by vagal fibre stimulation. Since eCB signalling is known to be an important component of homoeostatic regulation of the body and is regulated during various stressful conditions, we tested the hypothesis that food deprivation alters eCB signalling in central visceral afferent fibres. Food deprivation prevents eCB-LTD induction due to the absence of eCB signalling. This loss was reversed by blockade of ghrelin receptors. Activation of the cellular fuel sensor AMP-activated protein kinase or inhibition of the mechanistic target of rapamycin pathway abolished eCB-LTD in free-fed rats. Signals associated with energy surfeit, such as short-term refeeding, restore eCB-LTD induction, which in turn requires activation of cholecystokinin receptors and

  5. Novel Phosphorylation and Ubiquitination Sites Regulate Reactive Oxygen Species-dependent Degradation of Anti-apoptotic c-FLIP Protein*

    Science.gov (United States)

    Wilkie-Grantham, Rachel P.; Matsuzawa, Shu-Ichi; Reed, John C.

    2013-01-01

    The cytosolic protein c-FLIP (cellular Fas-associated death domain-like interleukin 1β-converting enzyme inhibitory protein) is an inhibitor of death receptor-mediated apoptosis that is up-regulated in a variety of cancers, contributing to apoptosis resistance. Several compounds found to restore sensitivity of cancer cells to TRAIL, a TNF family death ligand with promising therapeutic potential, act by targeting c-FLIP ubiquitination and degradation by the proteasome. The generation of reactive oxygen species (ROS) has been implicated in c-FLIP protein degradation. However, the mechanism by which ROS post-transcriptionally regulate c-FLIP protein levels is not well understood. We show here that treatment of prostate cancer PPC-1 cells with the superoxide generators menadione, paraquat, or buthionine sulfoximine down-regulates c-FLIP long (c-FLIPL) protein levels, which is prevented by the proteasome inhibitor MG132. Furthermore, pretreatment of PPC-1 cells with a ROS scavenger prevented ubiquitination and loss of c-FLIPL protein induced by menadione or paraquat. We identified lysine 167 as a novel ubiquitination site of c-FLIPL important for ROS-dependent degradation. We also identified threonine 166 as a novel phosphorylation site and demonstrate that Thr-166 phosphorylation is required for ROS-induced Lys-167 ubiquitination. The mutation of either Thr-166 or Lys-167 was sufficient to stabilize c-FLIP protein levels in PPC-1, HEK293T, and HeLa cancer cells treated with menadione or paraquat. Accordingly, expression of c-FLIP T166A or K167R mutants protected cells from ROS-mediated sensitization to TRAIL-induced cell death. Our findings reveal novel ROS-dependent post-translational modifications of the c-FLIP protein that regulate its stability, thus impacting sensitivity of cancer cells to TRAIL. PMID:23519470

  6. Models of Aire-dependent gene regulation for thymic negative selection

    Directory of Open Access Journals (Sweden)

    Dina eDanso-Abeam

    2011-05-01

    Full Text Available Mutations in the Autoimmune Regulator (AIRE gene lead to Autoimmune Polyendocrinopathy Syndrome type 1 (APS1, characterized by the development of multi-organ autoimmune damage. The mechanism by which defects in AIRE result in autoimmunity has been the subject of intense scrutiny. At the cellular level, the working model explains most of the clinical and immunological characteristics of APS1, with AIRE driving the expression of tissue restricted antigens (TRAs in the epithelial cells of the thymic medulla. This TRA expression results in effective negative selection of TRA-reactive thymocytes, preventing autoimmune disease. At the molecular level, the mechanism by which AIRE initiates TRA expression in the thymic medulla remains unclear. Multiple different models for the molecular mechanism have been proposed, ranging from classical transcriptional activity, to random induction of gene expression, to epigenetic tag recognition effect, to altered cell biology. In this review, we evaluate each of these models and discuss their relative strengths and weaknesses.

  7. Thioredoxin-2 (TRX-2) is an essential gene regulating mitochondria-dependent apoptosis.

    Science.gov (United States)

    Tanaka, Toru; Hosoi, Fumihito; Yamaguchi-Iwai, Yuko; Nakamura, Hajime; Masutani, Hiroshi; Ueda, Shugo; Nishiyama, Akira; Takeda, Shunichi; Wada, Hiromi; Spyrou, Giannis; Yodoi, Junji

    2002-04-02

    Thioredoxin-2 (Trx-2) is a mitochondria-specific member of the thioredoxin superfamily. Mitochondria have a crucial role in the signal transduction for apoptosis. To investigate the biological significance of Trx-2, we cloned chicken TRX-2 cDNA and generated clones of the conditional Trx-2-deficient cells using chicken B-cell line, DT40. Here we show that TRX-2 is an essential gene and that Trx-2-deficient cells undergo apoptosis upon repression of the TRX-2 transgene, showing an accumulation of intracellular reactive oxygen species (ROS). Cytochrome c is released from mitochondria, while caspase-9 and caspase-3, but not caspase-8, are activated upon inhibition of the TRX-2 transgene. In addition, Trx-2 and cytochrome c are co-immunoprecipitated in an in vitro assay. These results suggest that mitochondrial Trx-2 is essential for cell viability, playing a crucial role in the scavenging ROS in mitochondria and regulating the mitochondrial apoptosis signaling pathway.

  8. Catalytic promiscuity and heme-dependent redox regulation of H2S synthesis.

    Science.gov (United States)

    Banerjee, Ruma

    2017-04-01

    The view of enzymes as punctilious catalysts has been shifting as examples of their promiscuous behavior increase. However, unlike a number of cases where the physiological relevance of breached substrate specificity is questionable, the very synthesis of H 2 S relies on substrate and reaction promiscuity, which presents the enzymes with a multitude of substrate and reaction choices. The transsulfuration pathway, a major source of H 2 S, is inherently substrate-ambiguous. A heme-regulated switch embedded in the first enzyme in the pathway can help avert the stochastic production of cysteine versus H 2 S and control switching between metabolic tracks to meet cellular needs. This review discusses the dominant role of enzyme promiscuity in pathways that double as sulfur catabolic and H 2 S synthetic tracks. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Nidogen-1 regulates laminin-1-dependent mammary-specific gene expression

    Energy Technology Data Exchange (ETDEWEB)

    Pujuguet, Philippe; Simian, Marina; Liaw, Jane; Timpl, Rupert; Werb, Zena; Bissell, Mina J..

    2000-02-01

    Nidogen-1 (entactin) acts as a bridge between the extracellular matrix molecules laminin-1 and type IV collagen, and thus participates in the assembly of basement membranes. To investigate the role of nidogen-1 in regulating cell-type-specific gene expression in mammary epithelium, we designed a culture microecosystem in which each component, including epithelial cells, mesenchymal cells, lactogenic hormones and extracellular matrix, could be controlled. We found that primary and established mesenchymal and myoepithelial cells synthesized and secreted nidogen-1, whereas expression was absent in primary and established epithelial cells. In an epithelial cell line containing mesenchymal cells, nidogen-1 was produced by the mesenchymal cells but deposited between the epithelial cells. In this mixed culture, mammary epithelial cells express b-casein in the presence of lactogenic hormones. Addition of either laminin-1 plus nidogen-1, or laminin-1 alone to mammary epithelial cells induced b- casein production. We asked whether recombinant nidogen-1 alone could signal directly for b-casein. Nidogen-1 did not induce b-casein synthesis in epithelial cells, but it augmented the inductive capacity of laminin-1. These data suggest that nidogen-1 can cooperate with laminin-1 to regulate b-casein expression. Addition of full length nidogen-1 to the mixed cultures had no effect on b-casein gene expression; however, a nidogen-1 fragment containing the laminin-1 binding domain, but lacking the type IV collagen-binding domain, had a dominant negative effect on b-casein expression. These data point to a physiological role for nidogen-1 in the basement membrane-induced gene expression by epithelial cells.

  10. Effects of butyltin exposures on MAP kinase dependent transcription regulators in human natural killer cells

    Science.gov (United States)

    Person, Rachel J.; Whalen, Margaret M.

    2010-01-01

    Natural Killer (NK) cells are a major immune defense mechanism against cancer development and viral infection. The butyltins (BTs), tributyltin (TBT) and dibutyltin (DBT) have been widely used in industrial and other applications and significantly contaminate the environment. Both TBT and DBT have been detected in human blood. These compounds inhibit the lytic and binding function of human NK cells and thus could increase the incidence of cancer and viral infections. Butyltin (BT)-induced loss of NK function is accompanied by activation of mitogen activated protein kinases (MAPKs) and decreases in expression of cell-surface and cytolytic proteins. MAPKs activate components of the transcription regulator AP-1 and activate the transcription regulator Elk-1. Based on the fact that BTs activate MAPKs and alter protein expression, the current study examined the effect of BT exposures on the levels and phosphorylation states of the components of AP-1 and the phosphorylation state of Elk-1. Exposure to 300 nM TBT for 10 min increased the phosphorylation of c-Jun in NK cells. 1 h exposures to 300 nM and 200 nM TBT increased the phosphorylation and overall level of c-Jun. During a 300 nM treatment with TBT for 1 h the binding activity of AP-1 was significantly decreased. There were no significant alterations of AP-1 components or of Elk-1 with DBT exposures. Thus, it appears that TBT-induced alterations on phosphorylation, total levels and binding activity of c-Jun might contribute to, but are not fully responsible for, TBT-induced alterations of NK protein expression. PMID:20370538

  11. Erk5 inhibits endothelial migration via KLF2-dependent down-regulation of PAK1.

    Science.gov (United States)

    Komaravolu, Ravi K; Adam, Christian; Moonen, Jan-Renier A J; Harmsen, Martin C; Goebeler, Matthias; Schmidt, Marc

    2015-01-01

    The MEK5/Erk5 pathway mediates beneficial effects of laminar flow, a major physiological factor preventing vascular dysfunction. Forced Erk5 activation induces a protective phenotype in endothelial cell (EC) that is associated with a dramatically decreased migration capacity of those cells. Transcriptional profiling identified the Krüppel-like transcription factors KLF2 and KLF4 as central mediators of Erk5-dependent gene expression. However, their downstream role regarding migration is unclear and relevant secondary effectors remain elusive. Here, we further investigated the mechanism underlying Erk5-dependent migration arrest in ECs. Our experiments reveal KLF2-dependent loss of the pro-migratory Rac/Cdc42 mediator, p21-activated kinase 1 (PAK1), as an important mechanism of Erk5-induced migration inhibition. We show that endothelial Erk5 activation by expression of a constitutively active MEK5 mutant, by statin treatment, or by application of laminar shear stress strongly decreased PAK1 mRNA and protein expression. Knockdown of KLF2 but not of KLF4 prevented Erk5-mediated PAK1 mRNA inhibition, revealing KLF2 as a novel PAK1 repressor in ECs. Importantly, both PAK1 re-expression and KLF2 knockdown restored the migration capacity of Erk5-activated ECs underscoring their functional relevance downstream of Erk5. Our data provide first evidence for existence of a previously unknown Erk5/KLF2/PAK1 axis, which may limit undesired cell migration in unperturbed endothelium and lower its sensitivity for migratory cues that promote vascular diseases including atherosclerosis. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

  12. Flavivirus internalization is regulated by a size-dependent endocytic pathway.

    Science.gov (United States)

    Hackett, Brent A; Cherry, Sara

    2018-04-17

    Flaviviruses enter host cells through the process of clathrin-mediated endocytosis, and the spectrum of host factors required for this process are incompletely understood. Here we found that lymphocyte antigen 6 locus E (LY6E) promotes the internalization of multiple flaviviruses, including West Nile virus, Zika virus, and dengue virus. Perhaps surprisingly, LY6E is dispensable for the internalization of the endogenous cargo transferrin, which is also dependent on clathrin-mediated endocytosis for uptake. Since viruses are substantially larger than transferrin, we reasoned that LY6E may be required for uptake of larger cargoes and tested this using transferrin-coated beads of similar size as flaviviruses. LY6E was indeed required for the internalization of transferrin-coated beads, suggesting that LY6E is selectively required for large cargo. Cell biological studies found that LY6E forms tubules upon viral infection and bead internalization, and we found that tubule formation was dependent on RNASEK, which is also required for flavivirus internalization, but not transferrin uptake. Indeed, we found that RNASEK is also required for the internalization of transferrin-coated beads, suggesting it functions upstream of LY6E. These LY6E tubules resembled microtubules, and we found that microtubule assembly was required for their formation and flavivirus uptake. Since microtubule end-binding proteins link microtubules to downstream activities, we screened the three end-binding proteins and found that EB3 promotes virus uptake and LY6E tubularization. Taken together, these results highlight a specialized pathway required for the uptake of large clathrin-dependent endocytosis cargoes, including flaviviruses. Copyright © 2018 the Author(s). Published by PNAS.

  13. Features of Cytokine Regulation in Multidrug-Resistant Tuberculosis Depending on Severity of Endogenous Intoxication

    Directory of Open Access Journals (Sweden)

    L.D. Todoriko

    2016-02-01

    Conclusions. Comprehensive assessment of integral indices of endogenous intoxication and level of certain pro- and anti-inflammatory cytokines in the blood plasma of patients with MDR TB shows a moderate endogenous intoxication, break down of the cellular component of the immune reactivity due to the formation of conditions for the development of Mycobacterium tuberculosis resistance, with further growth of cytotoxic hypoxia and activation of systemic inflammatory response syndrome. Analysis of plasma concentration of IL-6, IL-10 and IL-18 in patients with multidrug-resistance proved, that their level depends on the nature of Mycobacterium tuberculosis resistance.

  14. Abscisic acid-dependent multisite phosphorylation regulates the activity of a transcription activator AREB1

    OpenAIRE

    Furihata, Takashi; Maruyama, Kyonoshin; Fujita, Yasunari; Umezawa, Taishi; Yoshida, Riichiro; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

    2006-01-01

    bZIP-type transcription factors AREBs/ABFs bind an abscisic acid (ABA)-responsive cis-acting element named ABRE and transactivate downstream gene expression in Arabidopsis. Because AREB1 overexpression could not induce downstream gene expression, activation of AREB1 requires ABA-dependent posttranscriptional modification. We confirmed that ABA activated 42-kDa kinase activity, which, in turn, phosphorylated Ser/Thr residues of R-X-X-S/T sites in the conserved regions of AREB1. Amino acid subs...

  15. Mg(2+),ATP-dependent plasma membrane calcium pump of smooth muscle cells. ІІ. Regulation of activity

    OpenAIRE

    T. О. Veklich; Iu. Iu. Mazur; S. О. Kosterin

    2015-01-01

    Plasma membrane Ca2+-pump is one of key proteins, which takes part in Ca2+ exchange in smooth muscle cells. It has a lot of diverse functions from control of basal cytoplasmal Ca2+ concentration to regulation of proteins involved in Ca2+-dependent signal pathway. Ca2+ pump function is often depen­dent on the isoform or even form of alternative splicing. Allowing for a variety of Ca2+-pump functions and properties, which were reviewed in detail in the first part of our review article cycle (U...

  16. Na,K-ATPase regulates intercellular communication in the vascular wall via cSrc kinase dependent connexin43 phosphorylation

    DEFF Research Database (Denmark)

    Hangaard, Lise; Bouzinova, Elena; Stæhr, Christian Albeck

    2017-01-01

    Communication between vascular smooth muscle cells (VSMCs) is dependent on gap junctions and is regulated by the Na-K-ATPase. The Na-K-ATPase is therefore important for synchronized VSMC oscillatory activity, i.e., vasomotion. The signaling between the Na-K-ATPase and gap junctions is unknown. We...... coupling in rat mesenteric small arteries in vitro. Phosphorylation of cSrc kinase and connexin43 (Cx43) were semiquantified by Western blotting. Micromole concentration of ouabain reduced the amplitude of norepinephrine-induced vasomotion and desynchronized Ca2+ transients in VSMC in the arterial wall...

  17. CC chemokine receptor 4 is required for experimental autoimmune encephalomyelitis by regulating GM-CSF and IL-23 production in dendritic cells

    Science.gov (United States)

    Poppensieker, Karola; Otte, David-Marian; Schürmann, Britta; Limmer, Andreas; Dresing, Philipp; Drews, Eva; Schumak, Beatrix; Klotz, Luisa; Raasch, Jennifer; Mildner, Alexander; Waisman, Ari; Scheu, Stefanie; Knolle, Percy; Förster, Irmgard; Prinz, Marco; Maier, Wolfgang; Zimmer, Andreas; Alferink, Judith

    2012-01-01

    Dendritic cells (DCs) are pivotal for the development of experimental autoimmune encephalomyelitis (EAE). However, the mechanisms by which they control disease remain to be determined. This study demonstrates that expression of CC chemokine receptor 4 (CCR4) by DCs is required for EAE induction. CCR4−/− mice presented enhanced resistance to EAE associated with a reduction in IL-23 and GM-CSF expression in the CNS. Restoring CCR4 on myeloid cells in bone marrow chimeras or intracerebral microinjection of CCR4-competent DCs, but not macrophages, restored EAE in CCR4−/− mice, indicating that CCR4+ DCs are cellular mediators of EAE development. Mechanistically, CCR4−/− DCs were less efficient in GM-CSF and IL-23 production and also TH-17 maintenance. Intraspinal IL-23 reconstitution restored EAE in CCR4−/− mice, whereas intracerebral inoculation using IL-23−/− DCs or GM-CSF−/− DCs failed to induce disease. Thus, CCR4-dependent GM-CSF production in DCs required for IL-23 release in these cells is a major component in the development of EAE. Our study identified a unique role for CCR4 in regulating DC function in EAE, harboring therapeutic potential for the treatment of CNS autoimmunity by targeting CCR4 on this specific cell type. PMID:22355103

  18. Discovery of a cAMP Deaminase That Quenches Cyclic AMP-Dependent Regulation

    Science.gov (United States)

    Goble, Alissa M.; Feng, Youjun; Raushel, Frank M.; Cronan, John E.

    2013-01-01

    An enzyme of unknown function within the amidohydrolase superfamily was discovered to catalyze the hydrolysis of the universal second messenger, cyclic-3’, 5’-adenosine monophosphate (cAMP). The enzyme, which we have named CadD, is encoded by the human pathogenic bacterium Leptospira interrogans. Although CadD is annotated as an adenosine deaminase, the protein specifically deaminates cAMP to cyclic-3’, 5’-inosine monophosphate (cIMP) with a kcat/Km of 2.7 ± 0.4 × 105 M−1 s−1 and has no activity on adenosine, adenine, or 5’-adenosine monophosphate (AMP). This is the first identification of a deaminase specific for cAMP. Expression of CadD in Escherichia coli mimics the loss of adenylate cyclase in that it blocks growth on carbon sources that require the cAMP-CRP transcriptional activator complex for expression of the cognate genes. The cIMP reaction product cannot replace cAMP as the ligand for CRP binding to DNA in vitro and cIMP is a very poor competitor of cAMP activation of CRP for DNA binding. Transcriptional analyses indicate that CadD expression represses expression of several cAMP-CRP dependent genes. CadD adds a new activity to the cAMP metabolic network and may be a useful tool in intracellular study of cAMP-dependent processes. PMID:24074367

  19. Matrix-Dependent Regulation of AKT in Hepsin-Overexpressing PC3 Prostate Cancer Cells12

    Science.gov (United States)

    Wittig-Blaich, Stephanie M; Kacprzyk, Lukasz A; Eismann, Thorsten; Bewerunge-Hudler, Melanie; Kruse, Petra; Winkler, Eva; Strauss, Wolfgang S L; Hibst, Raimund; Steiner, Rudolf; Schrader, Mark; Mertens, Daniel; Sültmann, Holger; Wittig, Rainer

    2011-01-01

    The serine-protease hepsin is one of the most prominently overexpressed genes in human prostate carcinoma. Forced expression of the enzyme in mice prostates is associated with matrix degradation, invasive growth, and prostate cancer progression. Conversely, hepsin overexpression in metastatic prostate cancer cell lines was reported to induce cell cycle arrest and reduction of invasive growth in vitro. We used a system for doxycycline (dox)-inducible target gene expression in metastasis-derived PC3 cells to analyze the effects of hepsin in a quantitative manner. Loss of viability and adhesion correlated with hepsin expression levels during anchorage-dependent but not anchorage-independent growth. Full expression of hepsin led to cell death and detachment and was specifically associated with reduced phosphorylation of AKT at Ser473, which was restored by growth on matrix derived from RWPE1 normal prostatic epithelial cells. In the chorioallantoic membrane xenograft model, hepsin overexpression in PC3 cells reduced the viability of tumors but did not suppress invasive growth. The data presented here provide evidence that elevated levels of hepsin interfere with cell adhesion and viability in the background of prostate cancer as well as other tissue types, the details of which depend on the microenvironment provided. Our findings suggest that overexpression of the enzyme in prostate carcinogenesis must be spatially and temporally restricted for the efficient development of tumors and metastases. PMID:21750652

  20. Matrix-Dependent Regulation of AKT in Hepsin-Overexpressing PC3 Prostate Cancer Cells

    Directory of Open Access Journals (Sweden)

    Stephanie M Wittig-Blaich

    2011-07-01

    Full Text Available The serine-protease hepsin is one of the most prominently overexpressed genes in human prostate carcinoma. Forced expression of the enzyme in mice prostates is associated with matrix degradation, invasive growth, and prostate cancer progression. Conversely, hepsin overexpression in metastatic prostate cancer cell lines was reported to induce cell cycle arrest and reduction of invasive growth in vitro. We used a system for doxycycline (dox-inducible target gene expression in metastasis-derived PC3 cells to analyze the effects of hepsin in a quantitative manner. Loss of viability and adhesion correlated with hepsin expression levels during anchorage-dependent but not anchorage-independent growth. Full expression of hepsin led to cell death and detachment and was specifically associated with reduced phosphorylation of AKT at Ser473, which was restored by growth on matrix derived from RWPE1 normal prostatic epithelial cells. In the chorioallantoic membrane xenograft model, hepsin overexpression in PC3 cells reduced the viability of tumors but did not suppress invasive growth. The data presented here provide evidence that elevated levels of hepsin interfere with cell adhesion and viability in the background of prostate cancer as well as other tissue types, the details of which depend on the microenvironment provided. Our findings suggest that overexpression of the enzyme in prostate carcinogenesis must be spatially and temporally restricted for the efficient development of tumors and metastases.

  1. Fragile X Mental Retardation Protein Regulates Activity-Dependent Membrane Trafficking and Trans-Synaptic Signaling Mediating Synaptic Remodeling

    Science.gov (United States)

    Sears, James C.; Broadie, Kendal

    2018-01-01

    Fragile X syndrome (FXS) is the leading monogenic cause of autism and intellectual disability. The disease arises through loss of fragile X mental retardation protein (FMRP), which normally exhibits peak expression levels in early-use critical periods, and is required for activity-dependent synaptic remodeling during this transient developmental window. FMRP canonically binds mRNA to repress protein translation, with targets that regulate cytoskeleton dynamics, membrane trafficking, and trans-synaptic signaling. We focus here on recent advances emerging in these three areas from the Drosophila disease model. In the well-characterized central brain mushroom body (MB) olfactory learning/memory circuit, FMRP is required for activity-dependent synaptic remodeling of projection neurons innervating the MB calyx, with function tightly restricted to an early-use critical period. FMRP loss is phenocopied by conditional removal of FMRP only during this critical period, and rescued by FMRP conditional expression only during this critical period. Consistent with FXS hyperexcitation, FMRP loss defects are phenocopied by heightened sensory experience and targeted optogenetic hyperexcitation during this critical period. FMRP binds mRNA encoding Drosophila ESCRTIII core component Shrub (human CHMP4 homolog) to restrict Shrub translation in an activity-dependent mechanism only during this same critical period. Shrub mediates endosomal membrane trafficking, and perturbing Shrub expression is known to interfere with neuronal process pruning. Consistently, FMRP loss and Shrub overexpression targeted to projection neurons similarly causes endosomal membrane trafficking defects within synaptic boutons, and genetic reduction of Shrub strikingly rescues Drosophila FXS model defects. In parallel work on the well-characterized giant fiber (GF) circuit, FMRP limits iontophoretic dye loading into central interneurons, demonstrating an FMRP role controlling core neuronal properties through the

  2. Time-dependent upregulation of electron transport with concomitant induction of regulated excitation dissipation in Haslea diatoms.

    Science.gov (United States)

    Perkins, R; Williamson, C; Lavaud, J; Mouget, J-L; Campbell, D A

    2018-04-16

    Photoacclimation by strains of Haslea "blue" diatom species H. ostrearia and H. silbo sp. nov. ined. was investigated with rapid light curves and induction-recovery curves using fast repetition rate fluorescence. Cultures were grown to exponential phase under 50 µmol m -2  s -1 photosynthetic available radiation (PAR) and then exposed to non-sequential rapid light curves where, once electron transport rate (ETR) had reached saturation, light intensity was decreased and then further increased prior to returning to near growth light intensity. The non-sequential rapid light curve revealed that ETR was not proportional to the instantaneously applied light intensity, due to rapid photoacclimation. Changes in the effective absorption cross sections for open PSII reaction centres (σ PSII ') or reaction centre connectivity (ρ) did not account for the observed increases in ETR under extended high light. σ PSII ' in fact decreased as a function of a time-dependent induction of regulated excitation dissipation Y(NPQ), once cells were at or above a PAR coinciding with saturation of ETR. Instead, the observed increases in ETR under extended high light were explained by an increase in the rate of PSII reopening, i.e. Q A - oxidation. This acceleration of electron transport was strictly light dependent and relaxed within seconds after a return to low light or darkness. The time-dependent nature of ETR upregulation and regulated NPQ induction was verified using induction-recovery curves. Our findings show a time-dependent induction of excitation dissipation, in parallel with very rapid photoacclimation of electron transport, which combine to make ETR independent of short-term changes in PAR. This supports a selective advantage for these diatoms when exposed to fluctuating light in their environment.

  3. TFIIS-Dependent Non-coding Transcription Regulates Developmental Genome Rearrangements.

    Directory of Open Access Journals (Sweden)

    Kamila Maliszewska-Olejniczak

    2015-07-01

    Full Text Available Because of their nuclear dimorphism, ciliates provide a unique opportunity to study the role of non-coding RNAs (ncRNAs in the communication between germline and somatic lineages. In these unicellular eukaryotes, a new somatic nucleus develops at each sexual cycle from a copy of the zygotic (germline nucleus, while the old somatic nucleus degenerates. In the ciliate Paramecium tetraurelia, the genome is massively rearranged during this process through the reproducible elimination of repeated sequences and the precise excision of over 45,000 short, single-copy Internal Eliminated Sequences (IESs. Different types of ncRNAs resulting from genome-wide transcription were shown to be involved in the epigenetic regulation of genome rearrangements. To understand how ncRNAs are produced from the entire genome, we have focused on a homolog of the TFIIS elongation factor, which regulates RNA polymerase II transcriptional pausing. Six TFIIS-paralogs, representing four distinct families, can be found in P. tetraurelia genome. Using RNA interference, we showed that TFIIS4, which encodes a development-specific TFIIS protein, is essential for the formation of a functional somatic genome. Molecular analyses and high-throughput DNA sequencing upon TFIIS4 RNAi demonstrated that TFIIS4 is involved in all kinds of genome rearrangements, including excision of ~48% of IESs. Localization of a GFP-TFIIS4 fusion revealed that TFIIS4 appears specifically in the new somatic nucleus at an early developmental stage, before IES excision. RT-PCR experiments showed that TFIIS4 is necessary for the synthesis of IES-containing non-coding transcripts. We propose that these IES+ transcripts originate from the developing somatic nucleus and serve as pairing substrates for germline-specific short RNAs that target elimination of their homologous sequences. Our study, therefore, connects the onset of zygotic non coding transcription to the control of genome plasticity in Paramecium

  4. Sphingosine 1-Phosphate (S1P) Carrier-dependent Regulation of Endothelial Barrier

    Science.gov (United States)

    Wilkerson, Brent A.; Grass, G. Daniel; Wing, Shane B.; Argraves, W. Scott; Argraves, Kelley M.

    2012-01-01

    Sphingosine 1-phosphate (S1P) is a blood-borne lysosphingolipid that acts to promote endothelial cell (EC) barrier function. In plasma, S1P is associated with both high density lipoproteins (HDL) and albumin, but it is not known whether the carriers impart different effects on S1P signaling. Here we establish that HDL-S1P sustains EC barrier longer than albumin-S1P. We showed that the sustained barrier effects of HDL-S1P are dependent on signaling by the S1P receptor, S1P1, and involve persistent activation of Akt and endothelial NOS (eNOS), as well as activity of the downstream NO target, soluble guanylate cyclase (sGC). Total S1P1 protein levels were found to be higher in response to HDL-S1P treatment as compared with albumin-S1P, and this effect was not associated with increased S1P1 mRNA or dependent on de novo protein synthesis. Several pieces of evidence indicate that long term EC barrier enhancement activity of HDL-S1P is due to specific effects on S1P1 trafficking. First, the rate of S1P1 degradation, which is proteasome-mediated, was slower in HDL-S1P-treated cells as compared with cells treated with albumin-S1P. Second, the long term barrier-promoting effects of HDL-S1P were abrogated by treatment with the recycling blocker, monensin. Finally, cell surface levels of S1P1 and levels of S1P1 in caveolin-enriched microdomains were higher after treatment with HDL-S1P as compared with albumin-S1P. Together, the findings reveal S1P carrier-specific effects on S1P1 and point to HDL as the physiological mediator of sustained S1P1-PI3K-Akt-eNOS-sGC-dependent EC barrier function. PMID:23135269

  5. The Transcription Factor ABI4 Is Required for the Ascorbic Acid–Dependent Regulation of Growth and Regulation of Jasmonate-Dependent Defense Signaling Pathways in Arabidopsis[C][W

    Science.gov (United States)

    Kerchev, Pavel I.; Pellny, Till K.; Vivancos, Pedro Diaz; Kiddle, Guy; Hedden, Peter; Driscoll, Simon; Vanacker, Hélène; Verrier, Paul; Hancock, Robert D.; Foyer, Christine H.

    2011-01-01

    Cellular redox homeostasis is a hub for signal integration. Interactions between redox metabolism and the ABSCISIC ACID-INSENSITIVE-4 (ABI4) transcription factor were characterized in the Arabidopsis thaliana vitamin c defective1 (vtc1) and vtc2 mutants, which are defective in ascorbic acid synthesis and show a slow growth phenotype together with enhanced abscisic acid (ABA) levels relative to the wild type (Columbia-0). The 75% decrease in the leaf ascorbate pool in the vtc2 mutants was not sufficient to adversely affect GA metabolism. The transcriptome signatures of the abi4, vtc1, and vtc2 mutants showed significant overlap, with a large number of transcription factors or signaling components similarly repressed or induced. Moreover, lincomycin-dependent changes in LIGHT HARVESTING CHLOROPHYLL A/B BINDING PROTEIN 1.1 expression were comparable in these mutants, suggesting overlapping participation in chloroplast to nucleus signaling. The slow growth phenotype of vtc2 was absent in the abi4 vtc2 double mutant, as was the sugar-insensitive phenotype of the abi4 mutant. Octadecanoid derivative-responsive AP2/ERF-domain transcription factor 47 (ORA47) and AP3 (an ABI5 binding factor) transcripts were enhanced in vtc2 but repressed in abi4 vtc2, suggesting that ABI4 and ascorbate modulate growth and defense gene expression through jasmonate signaling. We conclude that low ascorbate triggers ABA- and jasmonate-dependent signaling pathways that together regulate growth through ABI4. Moreover, cellular redox homeostasis exerts a strong influence on sugar-dependent growth regulation. PMID:21926335

  6. Leukocyte Overexpression of Intracellular NAMPT Attenuates Atherosclerosis by Regulating PPARγ-Dependent Monocyte Differentiation and Function.

    Science.gov (United States)

    Bermudez, Beatriz; Dahl, Tuva Borresdatter; Medina, Indira; Groeneweg, Mathijs; Holm, Sverre; Montserrat-de la Paz, Sergio; Rousch, Mat; Otten, Jeroen; Herias, Veronica; Varela, Lourdes M; Ranheim, Trine; Yndestad, Arne; Ortega-Gomez, Almudena; Abia, Rocio; Nagy, Laszlo; Aukrust, Pal; Muriana, Francisco J G; Halvorsen, Bente; Biessen, Erik Anna Leonardus

    2017-06-01

    Extracellular nicotinamide phosphoribosyltransferase (eNAMPT) mediates inflammatory and potentially proatherogenic effects, whereas the role of intracellular NAMPT (iNAMPT), the rate limiting enzyme in the salvage pathway of nicotinamide adenine dinucleotide (NAD) + generation, in atherogenesis is largely unknown. Here we investigated the effects of iNAMPT overexpression in leukocytes on inflammation and atherosclerosis. Low-density lipoprotein receptor-deficient mice with hematopoietic overexpression of human iNAMPT (iNAMPT hi ), on a western type diet, showed attenuated plaque burden with features of lesion stabilization. This anti-atherogenic effect was caused by improved resistance of macrophages to apoptosis by attenuated chemokine (C-C motif) receptor 2-dependent monocyte chemotaxis and by skewing macrophage polarization toward an anti-inflammatory M2 phenotype. The iNAMPT hi phenotype was almost fully reversed by treatment with the NAMPT inhibitor FK866, indicating that iNAMPT catalytic activity is instrumental in the atheroprotection. Importantly, iNAMPT overexpression did not induce any increase in eNAMPT, and eNAMPT had no effect on chemokine (C-C motif) receptor 2 expression and promoted an inflammatory M1 phenotype in macrophages. The iNAMPT-mediated effects at least partly involved sirtuin 1-dependent molecular crosstalk of NAMPT and peroxisome proliferator-activated receptor γ. Finally, iNAMPT and peroxisome proliferator-activated receptor γ showed a strong correlation in human atherosclerotic, but not healthy arteries, hinting to a relevance of iNAMPT/peroxisome proliferator-activated receptor γ pathway also in human carotid atherosclerosis. This study highlights the functional dichotomy of intracellular versus extracellular NAMPT, and unveils a critical role for the iNAMPT-peroxisome proliferator-activated receptor γ axis in atherosclerosis. © 2017 American Heart Association, Inc.

  7. Voltage-gated potassium channels regulate calcium-dependent pathways involved in human T lymphocyte activation.

    Science.gov (United States)

    Lin, C S; Boltz, R C; Blake, J T; Nguyen, M; Talento, A; Fischer, P A; Springer, M S; Sigal, N H; Slaughter, R S; Garcia, M L

    1993-03-01

    The role that potassium channels play in human T lymphocyte activation has been investigated by using specific potassium channel probes. Charybdotoxin (ChTX), a blocker of small conductance Ca(2+)-activated potassium channels (PK,Ca) and voltage-gated potassium channels (PK,V) that are present in human T cells, inhibits the activation of these cells. ChTX blocks T cell activation induced by signals (e.g., anti-CD2, anti-CD3, ionomycin) that elicit a rise in intracellular calcium ([Ca2+]i) by preventing the elevation of [Ca2+]i in a dose-dependent manner. However, ChTX has no effect on the activation pathways (e.g., anti-CD28, interleukin 2 [IL-2]) that are independent of a rise in [Ca2+]i. In the former case, both proliferative response and lymphokine production (IL-2 and interferon gamma) are inhibited by ChTX. The inhibitory effect of ChTX can be demonstrated when added simultaneously, or up to 4 h after the addition of the stimulants. Since ChTX inhibits both PK,Ca and PK,V, we investigated which channel is responsible for these immunosuppressive effects with the use of two other peptides, noxiustoxin (NxTX) and margatoxin (MgTX), which are specific for PK,V. These studies demonstrate that, similar to ChTX, both NxTX and MgTX inhibit lymphokine production and the rise in [Ca2+]i. Taken together, these data provide evidence that blockade of PK,V affects the Ca(2+)-dependent pathways involved in T lymphocyte proliferation and lymphokine production by diminishing the rise in [Ca2+]i that occurs upon T cell activation.

  8. Cysteine-dependent immune regulation by TRX and MIF/GIF family proteins.

    Science.gov (United States)

    Kondo, Norihiko; Ishii, Yasuyuki; Son, Aoi; Sakakura-Nishiyama, Junko; Kwon, Yong-Won; Tanito, Masaki; Nishinaka, Yumiko; Matsuo, Yoshiyuki; Nakayama, Toshinori; Taniguchi, Masaru; Yodoi, Junji

    2004-03-29

    Thioredoxin (TRX) superfamily proteins that contain a conserved redox-active site -Cys-Xa.a.-Xa.a.-Cys- includes proinflammatory cytokine, macrophage migration inhibiting factor (MIF) and the immune regulatory cytokine, glycosylation inhibiting factor (GIF) in which Cys-60 is cysteinylated. In this report, we have analyzed the functional interaction between TRX and MIF/GIF. The stable Jurkat T cell line transfected with human TRX gene (TRX-transfectant) was highly resistant to hydrogen peroxide-induced apoptosis, but not the cell line transfected with vector (mock-transfectant). The expression level of MIF/GIF protein of TRX-transfectant was lower than that of mock-transfectant. Conversely, the expression level of intracellular TRX protein in CD4(+)-T cells derived from MIF -/- mice were significantly higher than that from background BALB/c mice. These findings collectively suggest that oxidative stress-induced apoptosis on T lymphocytes might be protected by the reciprocal regulation of TRX and MIF/GIF expression.

  9. Evolution of context dependent regulation by expansion of feast/famine regulatory proteins.

    Science.gov (United States)

    Plaisier, Christopher L; Lo, Fang-Yin; Ashworth, Justin; Brooks, Aaron N; Beer, Karlyn D; Kaur, Amardeep; Pan, Min; Reiss, David J; Facciotti, Marc T; Baliga, Nitin S

    2014-11-14

    Expansion of transcription factors is believed to have played a crucial role in evolution of all organisms by enabling them to deal with dynamic environments and colonize new environments. We investigated how the expansion of the Feast/Famine Regulatory Protein (FFRP) or Lrp-like proteins into an eight-member family in Halobacterium salinarum NRC-1 has aided in niche-adaptation of this archaeon to a complex and dynamically changing hypersaline environment. We mapped genome-wide binding locations for all eight FFRPs, investigated their preference for binding different effector molecules, and identified the contexts in which they act by analyzing transcriptional responses across 35 growth conditions that mimic different environmental and nutritional conditions this organism is likely to encounter in the wild. Integrative analysis of these data constructed an FFRP regulatory network with conditionally active states that reveal how interrelated variations in DNA-binding domains, effector-molecule preferences, and binding sites in target gene promoters have tuned the functions of each FFRP to the environments in which they act. We demonstrate how conditional regulation of similar genes by two FFRPs, AsnC (an activator) and VNG1237C (a repressor), have striking environment-specific fitness consequences for oxidative stress management and growth, respectively. This study provides a systems perspective into the evolutionary process by which gene duplication within a transcription factor family contributes to environment-specific adaptation of an organism.

  10. GTSE1 is a microtubule plus-end tracking protein that regulates EB1-dependent cell migration.

    Directory of Open Access Journals (Sweden)

    Massimilano Scolz

    Full Text Available The regulation of cell migration is a highly complex process that is often compromised when cancer cells become metastatic. The microtubule cytoskeleton is necessary for cell migration, but how microtubules and microtubule-associated proteins regulate multiple pathways promoting cell migration remains unclear. Microtubule plus-end binding proteins (+TIPs are emerging as important players in many cellular functions, including cell migration. Here we identify a +TIP, GTSE1, that promotes cell migration. GTSE1 accumulates at growing microtubule plus ends through interaction with the EB1+TIP. The EB1-dependent +TIP activity of GTSE1 is required for cell migration, as well as for microtubule-dependent disassembly of focal adhesions. GTSE1 protein levels determine the migratory capacity of both nontransformed and breast cancer cell lines. In breast cancers, increased GTSE1 expression correlates with invasive potential, tumor stage, and time to distant metastasis, suggesting that misregulation of GTSE1 expression could be associated with increased invasive potential.

  11. Palmitoylation-dependent CDKL5–PSD-95 interaction regulates synaptic targeting of CDKL5 and dendritic spine development

    Science.gov (United States)

    Zhu, Yong-Chuan; Li, Dan; Wang, Lu; Lu, Bin; Zheng, Jing; Zhao, Shi-Lin; Zeng, Rong; Xiong, Zhi-Qi

    2013-01-01

    The X-linked gene cyclin-dependent kinase-like 5 (CDKL5) is mutated in severe neurodevelopmental disorders, including some forms of atypical Rett syndrome, but the function and regulation of CDKL5 protein in neurons remain to be elucidated. Here, we show that CDKL5 binds to the scaffolding protein postsynaptic density (PSD)-95, and that this binding promotes the targeting of CDKL5 to excitatory synapses. Interestingly, this binding is not constitutive, but governed by palmitate cycling on PSD-95. Furthermore, pathogenic mutations that truncate the C-terminal tail of CDKL5 diminish its binding to PSD-95 and synaptic accumulation. Importantly, down-regulation of CDKL5 by RNA interference (RNAi) or interference with the CDKL5–PSD-95 interaction inhibits dendritic spine formation and growth. These results demonstrate a critical role of the palmitoylation-dependent CDKL5–PSD-95 interaction in localizing CDKL5 to synapses for normal spine development and suggest that disruption of this interaction by pathogenic mutations may be implicated in the pathogenesis of CDKL5-related disorders. PMID:23671101

  12. Palmitoylation-dependent CDKL5-PSD-95 interaction regulates synaptic targeting of CDKL5 and dendritic spine development.

    Science.gov (United States)

    Zhu, Yong-Chuan; Li, Dan; Wang, Lu; Lu, Bin; Zheng, Jing; Zhao, Shi-Lin; Zeng, Rong; Xiong, Zhi-Qi

    2013-05-28

    The X-linked gene cyclin-dependent kinase-like 5 (CDKL5) is mutated in severe neurodevelopmental disorders, including some forms of atypical Rett syndrome, but the function and regulation of CDKL5 protein in neurons remain to be elucidated. Here, we show that CDKL5 binds to the scaffolding protein postsynaptic density (PSD)-95, and that this binding promotes the targeting of CDKL5 to excitatory synapses. Interestingly, this binding is not constitutive, but governed by palmitate cycling on PSD-95. Furthermore, pathogenic mutations that truncate the C-terminal tail of CDKL5 diminish its binding to PSD-95 and synaptic accumulation. Importantly, down-regulation of CDKL5 by RNA interference (RNAi) or interference with the CDKL5-PSD-95 interaction inhibits dendritic spine formation and growth. These results demonstrate a critical role of the palmitoylation-dependent CDKL5-PSD-95 interaction in localizing CDKL5 to synapses for normal spine development and suggest that disruption of this interaction by pathogenic mutations may be implicated in the pathogenesis of CDKL5-related disorders.

  13. Salinity-dependent nickel accumulation and effects on respiration, ion regulation and oxidative stress in the galaxiid fish, Galaxias maculatus.

    Science.gov (United States)

    Blewett, Tamzin A; Wood, Chris M; Glover, Chris N

    2016-07-01

    Inanga (Galaxias maculatus) are a euryhaline and amphidromous Southern hemisphere fish species inhabiting waters highly contaminated in trace elements such as nickel (Ni). Ni is known to exert its toxic effects on aquatic biota via three key mechanisms: inhibition of respiration, impaired ion regulation, and stimulation of oxidative stress. Inanga acclimated to freshwater (FW), 50% seawater (SW) or 100% SW were exposed to 0, 150 or 2000 μg Ni L(-1), and tissue Ni accumulation, metabolic rate, ion regulation (tissue ions, calcium (Ca) ion influx), and oxidative stress (catalase activity, protein carbonylation) were measured after 96 h. Ni accumulation increased with Ni exposure concentration in gill, gut and remaining body, but not in liver. Only in the gill was Ni accumulation affected by exposure salinity, with lower branchial Ni burdens in 100% and 50% SW inanga, relative to FW fish. There were no Ni-dependent effects on respiration, or Ca influx, and the only Ni-dependent effect on tissue ion content was on gill potassium. Catalase activity and protein carbonylation were affected by Ni, primarily in FW, but only at 150 μg Ni L(-1). Salinity therefore offsets the effects of Ni, despite minimal changes in Ni bioavailability. These data suggest only minor effects of Ni in inanga, even at highly elevated environmental Ni concentrations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Response and binding elements for ligand-dependent positive transcription factors integrate positive and negative regulation of gene expression

    International Nuclear Information System (INIS)

    Rosenfeld, M.G.; Glass, C.K.; Adler, S.; Crenshaw, E.B. III; He, X.; Lira, S.A.; Elsholtz, H.P.; Mangalam, H.J.; Holloway, J.M.; Nelson, C.; Albert, V.R.; Ingraham, H.A.

    1988-01-01

    Accurate, regulated initiation of mRNA transcription by RNA polymerase II is dependent on the actions of a variety of positive and negative trans-acting factors that bind cis-acting promoter and enhancer elements. These transcription factors may exert their actions in a tissue-specific manner or function under control of plasma membrane or intracellular ligand-dependent receptors. A major goal in the authors' laboratory has been to identify the molecular mechanisms responsible for the serial activation of hormone-encoding genes in the pituitary during development and the positive and negative regulation of their transcription. The anterior pituitary gland contains phenotypically distinct cell types, each of which expresses unique trophic hormones: adrenocorticotropic hormone, thyroid-stimulating hormone, prolactin, growth hormone, and follicle-stimulating hormone/luteinizing hormone. The structurally related prolactin and growth hormone genes are expressed in lactotrophs and somatotrophs, respectively, with their expression virtually limited to the pituitary gland. The reported transient coexpression of these two structurally related neuroendocrine genes raises the possibility that the prolactin and growth hormone genes are developmentally controlled by a common factor(s)

  15. Proteomic analysis reveals APC-dependent post-translational modifications and identifies a novel regulator of β-catenin.

    Science.gov (United States)

    Blundon, Malachi A; Schlesinger, Danielle R; Parthasarathy, Amritha; Smith, Samantha L; Kolev, Hannah M; Vinson, David A; Kunttas-Tatli, Ezgi; McCartney, Brooke M; Minden, Jonathan S

    2016-07-15

    Wnt signaling generates patterns in all embryos, from flies to humans, and controls cell fate, proliferation and metabolic homeostasis. Inappropriate Wnt pathway activation results in diseases, including colorectal cancer. The adenomatous polyposis coli (APC) tumor suppressor gene encodes a multifunctional protein that is an essential regulator of Wnt signaling and cytoskeletal organization. Although progress has been made in defining the role of APC in a normal cellular context, there are still significant gaps in our understanding of APC-dependent cellular function and dysfunction. We expanded the APC-associated protein network using a combination of genetics and a proteomic technique called two-dimensional difference gel electrophoresis (2D-DIGE). We show that loss of Drosophila Apc2 causes protein isoform changes reflecting misregulation of post-translational modifications (PTMs), which are not dependent on β-catenin transcriptional activity. Mass spectrometry revealed that proteins involved in metabolic and biosynthetic pathways, protein synthesis and degradation, and cell signaling are affected by Apc2 loss. We demonstrate that changes in phosphorylation partially account for the altered PTMs in APC mutants, suggesting that APC mutants affect other types of PTM. Finally, through this approach Aminopeptidase P was identified as a new regulator of β-catenin abundance in Drosophila embryos. This study provides new perspectives on the cellular effects of APC that might lead to a deeper understanding of its role in development. © 2016. Published by The Company of Biologists Ltd.

  16. PICK1 regulates the trafficking of ASIC1a and acidotoxicity in a BAR domain lipid binding-dependent manner

    Directory of Open Access Journals (Sweden)

    Jin Wenying

    2010-12-01

    Full Text Available Abstract Background Acid-sensing ion channel 1a (ASIC1a is the major ASIC subunit determining acid-activated currents in brain neurons. Recent studies show that ASIC1a play critical roles in acid-induced cell toxicity. While these studies raise the importance of ASIC1a in diseases, mechanisms for ASIC1a trafficking are not well understood. Interestingly, ASIC1a interacts with PICK1 (protein interacting with C-kinase 1, an intracellular protein that regulates trafficking of several membrane proteins. However, whether PICK1 regulates ASIC1a surface expression remains unknown. Results Here, we show that PICK1 overexpression increases ASIC1a surface level. A BAR domain mutant of PICK1, which impairs its lipid binding capability, blocks this increase. Lipid binding of PICK1 is also required for PICK1-induced clustering of ASIC1a. Consistent with the effect on ASIC1a surface levels, PICK1 increases ASIC1a-mediated acidotoxicity and this effect requires both the PDZ and BAR domains of PICK1. Conclusions Taken together, our results indicate that PICK1 regulates trafficking and function of ASIC1a in a lipid binding-dependent manner.

  17. Role of Dlx6 in regulation of an endothelin-1-dependent, dHAND branchial arch enhancer

    Science.gov (United States)

    Charité, Jeroen; McFadden, David G.; Merlo, Giorgio; Levi, Giovanni; Clouthier, David E.; Yanagisawa, Masashi; Richardson, James A.; Olson, Eric N.

    2001-01-01

    Neural crest cells play a key role in craniofacial development. The endothelin family of secreted polypeptides regulates development of several neural crest sublineages, including the branchial arch neural crest. The basic helix–loop–helix transcription factor dHAND is also required for craniofacial development, and in endothelin-1 (ET-1) mutant embryos, dHAND expression in the branchial arches is down-regulated, implicating it as a transcriptional effector of ET-1 action. To determine the mechanism that links ET-1 signaling to dHAND transcription, we analyzed the dHAND gene for cis-regulatory elements that control transcription in the branchial arches. We describe an evolutionarily conserved dHAND enhancer that requires ET-1 signaling for activity. This enhancer contains four homeodomain binding sites that are required for branchial arch expression. By comparing protein binding to these sites in branchial arch extracts from endothelin receptor A (EdnrA) mutant and wild-type mouse embryos, we identified Dlx6, a member of the Distal-less family of homeodomain proteins, as an ET-1-dependent binding factor. Consistent with this conclusion, Dlx6 was down-regulated in branchial arches from EdnrA mutant mice. These results suggest that Dlx6 acts as an intermediary between ET-1 signaling and dHAND transcription during craniofacial morphogenesis. PMID:11711438

  18. Raf Kinase Inhibitory Protein Function Is Regulated via a Flexible Pocket and Novel Phosphorylation-Dependent Mechanism▿ †

    Science.gov (United States)

    Granovsky, Alexey E.; Clark, Matthew C.; McElheny, Dan; Heil, Gary; Hong, Jia; Liu, Xuedong; Kim, Youngchang; Joachimiak, Grazyna; Joachimiak, Andrzej; Koide, Shohei; Rosner, Marsha Rich

    2009-01-01

    Raf kinase inhibitory protein (RKIP/PEBP1), a member of the phosphatidylethanolamine binding protein family that possesses a conserved ligand-binding pocket, negatively regulates the mammalian mitogen-activated protein kinase (MAPK) signaling cascade. Mutation of a conserved site (P74L) within the pocket leads to a loss or switch in the function of yeast or plant RKIP homologues. However, the mechanism by which the pocket influences RKIP function is unknown. Here we show that the pocket integrates two regulatory signals, phosphorylation and ligand binding, to control RKIP inhibition of Raf-1. RKIP association with Raf-1 is prevented by RKIP phosphorylation at S153. The P74L mutation increases kinase interaction and RKIP phosphorylation, enhancing Raf-1/MAPK signaling. Conversely, ligand binding to the RKIP pocket inhibits kinase interaction and RKIP phosphorylation by a noncompetitive mechanism. Additionally, ligand binding blocks RKIP association with Raf-1. Nuclear magnetic resonance studies reveal that the pocket is highly dynamic, rationalizing its capacity to interact with distinct partners and be involved in allosteric regulation. Our results show that RKIP uses a flexible pocket to integrate ligand binding- and phosphorylation-dependent interactions and to modulate the MAPK signaling pathway. This mechanism is an example of an emerging theme involving the regulation of signaling proteins and their interaction with effectors at the level of protein dynamics. PMID:19103740

  19. Raf kinase inhibitory protein function is regulated via a flexible pocket and novel phosphorylation-dependent mechanism.

    Science.gov (United States)

    Granovsky, Alexey E; Clark, Matthew C; McElheny, Dan; Heil, Gary; Hong, Jia; Liu, Xuedong; Kim, Youngchang; Joachimiak, Grazyna; Joachimiak, Andrzej; Koide, Shohei; Rosner, Marsha Rich

    2009-03-01

    Raf kinase inhibitory protein (RKIP/PEBP1), a member of the phosphatidylethanolamine binding protein family that possesses a conserved ligand-binding pocket, negatively regulates the mammalian mitogen-activated protein kinase (MAPK) signaling cascade. Mutation of a conserved site (P74L) within the pocket leads to a loss or switch in the function of yeast or plant RKIP homologues. However, the mechanism by which the pocket influences RKIP function is unknown. Here we show that the pocket integrates two regulatory signals, phosphorylation and ligand binding, to control RKIP inhibition of Raf-1. RKIP association with Raf-1 is prevented by RKIP phosphorylation at S153. The P74L mutation increases kinase interaction and RKIP phosphorylation, enhancing Raf-1/MAPK signaling. Conversely, ligand binding to the RKIP pocket inhibits kinase interaction and RKIP phosphorylation by a noncompetitive mechanism. Additionally, ligand binding blocks RKIP association with Raf-1. Nuclear magnetic resonance studies reveal that the pocket is highly dynamic, rationalizing its capacity to interact with distinct partners and be involved in allosteric regulation. Our results show that RKIP uses a flexible pocket to integrate ligand binding- and phosphorylation-dependent interactions and to modulate the MAPK signaling pathway. This mechanism is an example of an emerging theme involving the regulation of signaling proteins and their interaction with effectors at the level of protein dynamics.

  20. Listeria monocytogenes differential transcriptome analysis reveals temperature-dependent Agr regulation and suggests overlaps with other regulons.

    Science.gov (United States)

    Garmyn, Dominique; Augagneur, Yoann; Gal, Laurent; Vivant, Anne-Laure; Piveteau, Pascal

    2012-01-01

    Listeria monocytogenes is a ubiquitous, opportunistic pathogenic organism. Environmental adaptation requires constant regulation of gene expression. Among transcriptional regulators, AgrA is part of an auto-induction system. Temperature is an environmental cue critical for in vivo adaptation. In order to investigate how temperature may affect AgrA-dependent transcription, we compared the transcriptomes of the parental strain L. monocytogenes EGD-e and its ΔagrA mutant at the saprophytic temperature of 25°C and in vivo temperature of 37°C. Variations of transcriptome were higher at 37°C than at 25°C. Results suggested that AgrA may be involved in the regulation of nitrogen transport, amino acids, purine and pyrimidine biosynthetic pathways and phage-related functions. Deregulations resulted in a growth advantage at 37°C, but affected salt tolerance. Finally, our results suggest overlaps with PrfA, σB, σH and CodY regulons. These overlaps may suggest that through AgrA, Listeria monocytogenes integrates information on its biotic environment.

  1. Suppressor of fusion, a Fusarium oxysporum homolog of Ndt80, is required for nutrient-dependent regulation of anastomosis.

    Science.gov (United States)

    Shahi, Shermineh; Fokkens, Like; Houterman, Petra M; Rep, Martijn

    2016-10-01

    Heterokaryon formation is an essential step in asexual recombination in Fusarium oxysporum. Filamentous fungi have an elaborate nonself recognition machinery to prevent formation and proliferation of heterokaryotic cells, called heterokaryon incompatibility (HI). In F. oxysporum the regulation of this machinery is not well understood. In Neurospora crassa, Vib-1, a putative transcription factor of the p53-like Ndt80 family of transcription factors, has been identified as global regulator of HI. In this study we investigated the role of the F. oxysporum homolog of Vib-1, called Suf, in vegetative hyphal and conidial anastomosis tube (CAT) fusion and HI. We identified a novel function for an Ndt80 homolog as a nutrient-dependent regulator of anastomosis. Strains carrying the SUF deletion mutation display a hyper-fusion phenotype during vegetative growth as well as germling development. In addition, conidial paring of incompatible SUF deletion strains led to more heterokaryon formation, which is independent of suppression of HI. Our data provides further proof for the divergence in the functions of different members Ndt80 family. We propose that Ndt80 homologs mediate responses to nutrient quality and quantity, with specific responses varying between species. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. PKA- and PKC-dependent regulation of angiopoietin 2 mRNA in human granulosa lutein cells.

    Science.gov (United States)

    Witt, P S; Pietrowski, D; Keck, C

    2004-02-01

    New blood vessels develop from preexisting vessels in response to growth factors or hypoxic conditions. Recent studies have shown that angiopoietin 2 (ANGPT-2) plays an important role in the modulation of angiogenesis and vasculogenesis in humans and mice. The signaling pathways that lead to the regulation of ANGPT-2 are largely unclear. Here, we report that protein kinase C and protein kinase A activators (ADMB, 8-Cl-cAMP) increased the mRNA levels of ANGPT-2 in human Granulosa cells, whereas PKC and PKA Inhibitors (Rp-cAMP, GO 6983) decreased markedly the level of ANGPT-2 mRNA. Due to varying specificity of the modulators for certain protein kinases subunits, we conclude that the conventional PKCs, but not PKC alpha and beta1, the atypical PKCs and the PKA I, are involved in the regulation of ANGPT-2. These findings may help to explain the role of both PKA and PKC dependent signaling cascades in the regulation of ANGPT-2 mRNA.

  3. Heme-dependent Metabolite Switching Regulates H2S Synthesis in Response to Endoplasmic Reticulum (ER) Stress.

    Science.gov (United States)

    Kabil, Omer; Yadav, Vinita; Banerjee, Ruma

    2016-08-05

    Substrate ambiguity and relaxed reaction specificity underlie the diversity of reactions catalyzed by the transsulfuration pathway enzymes, cystathionine β-synthase (CBS) and γ-cystathionase (CSE). These enzymes either commit sulfur metabolism to cysteine synthesis from homocysteine or utilize cysteine and/or homocysteine for synthesis of H2S, a signaling molecule. We demonstrate that a kinetically controlled heme-dependent metabolite switch in CBS regulates these competing reactions where by cystathionine, the product of CBS, inhibits H2S synthesis by the second enzyme, CSE. Under endoplasmic reticulum stress conditions, induction of CSE and up-regulation of the CBS inhibitor, CO, a product of heme oxygenase-1, flip the operating preference of CSE from cystathionine to cysteine, transiently stimulating H2S production. In contrast, genetic deficiency of CBS leads to chronic stimulation of H2S production. This metabolite switch from cystathionine to cysteine and/or homocysteine renders H2S synthesis by CSE responsive to the known modulators of CBS: S-adenosylmethionine, NO, and CO. Used acutely, it regulates H2S synthesis; used chronically, it might contribute to disease pathology. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  4. PV Interneurons: Critical Regulators of E/I Balance for Prefrontal Cortex-Dependent Behavior and Psychiatric Disorders

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    Brielle R. Ferguson

    2018-05-01

    Full Text Available Elucidating the prefrontal cortical microcircuit has been challenging, given its role in multiple complex behaviors, including working memory, cognitive flexibility, attention, social interaction and emotional regulation. Additionally, previous methodological limitations made it difficult to parse out the contribution of certain neuronal subpopulations in refining cortical representations. However, growing evidence supports a fundamental role of fast-spiking parvalbumin (PV GABAergic interneurons in regulating pyramidal neuron activity to drive appropriate behavioral responses. Further, their function is heavily diminished in the prefrontal cortex (PFC in numerous psychiatric diseases, including schizophrenia and autism. Previous research has demonstrated the importance of the optimal balance of excitation and inhibition (E/I in cortical circuits in maintaining the efficiency of cortical information processing. Although we are still unraveling the mechanisms of information representation in the PFC, the E/I balance seems to be crucial, as pharmacological, chemogenetic and optogenetic approaches for disrupting E/I balance induce impairments in a range of PFC-dependent behaviors. In this review, we will explore two key hypotheses. First, PV interneurons are powerful regulators of E/I balance in the PFC, and help optimize the representation and processing of supramodal information in PFC. Second, diminishing the function of PV interneurons is sufficient to generate an elaborate symptom sequelae corresponding to those observed in a range of psychiatric diseases. Then, using this framework, we will speculate on whether this circuitry could represent a platform for the development of therapeutic interventions in disorders of PFC function.

  5. Presynaptic Regulation of Leptin in a Defined Lateral Hypothalamus-Ventral Tegmental Area Neurocircuitry Depends on Energy State.

    Science.gov (United States)

    Liu, Jing-Jing; Bello, Nicholas T; Pang, Zhiping P

    2017-12-06

    Synaptic transmission controls brain activity and behaviors, including food intake. Leptin, an adipocyte-derived hormone, acts on neurons located in the lateral hypothalamic area (LHA) to maintain energy homeostasis and regulate food intake behavior. The specific synaptic mechanisms, cell types, and neural projections mediating this effect remain unclear. In male mice, using pathway-specific retrograde tracing, whole-cell patch-clamp recordings and post hoc cell type identification, we found that leptin reduces excitatory synaptic strength onto both melanin-concentrating hormone- and orexin-expressing neurons projecting from the LHA to the ventral tegmental area (VTA), which may affect dopamine signaling and motivation for feeding. A presynaptic mechanism mediated by distinct intracellular signaling mechanisms may account for this regulation by leptin. The regulatory effects of leptin depend on intact leptin receptor signaling. Interestingly, the synaptic regulatory function of leptin in the LHA-to-VTA neuronal pathway is highly sensitive to energy states: both energy deficiency (acute fasting) and excessive energy storage (high-fat diet-induced obesity) blunt the effect of leptin. These data revealed that leptin may regulate synaptic transmission in the LHA-to-VTA neurocircuitry in an inverted "U-shape" fashion dependent on plasma glucose levels and related to metabolic states. SIGNIFICANCE STATEMENT The lateral hypothalamic area (LHA) to ventral tegmental area (VTA) projection is an important neural pathway involved in balancing whole-body energy states and reward. We found that the excitatory synaptic inputs to both orexin- and melanin-concentrating hormone expressing LHA neurons projecting to the VTA were suppressed by leptin, a peptide hormone derived from adipocytes that signals peripheral energy status to the brain. Interestingly, energy states seem to affect how leptin regulates synaptic transmission since both the depletion of energy induced by acute food

  6. Dopamine D1 receptor-dependent regulation of extracellular citrulline level in the rat nucleus accumbens during conditioned fear response.

    Science.gov (United States)

    Saulskaya, Natalia B; Fofonova, Nellia V; Sudorghina, Polina V; Saveliev, Sergey A

    2008-08-01

    Nucleus accumbens (N.Acc) contains a subclass of nitric oxide (NO)-generating interneurons that are presumably regulated by the dopamine input. Receptor mechanisms underlying dopamine-NO interaction in the N.Acc are poorly understood. In the current study, we used in vivo microdialysis combined with high-performance liquid chromatography to examine participation of dopamine D1 receptors in regulation of extracellular levels of citrulline (an NO co-product) in the medial N.Acc of Sprague-Dawley rats during both pharmacological challenge and a conditioned fear response. The intraaccumbal infusion of the D1 receptor agonist SKF-38393 (100-500 microM) increased dose-dependently the local dialysate citrulline levels. The SKF-38393-induced increase in extracellular citrulline was prevented by intraaccumbal infusions of 500 microM 7-nitroindazole, a neuronal NO synthase inhibitor. In behavioral microdialysis experiment, the accumbal levels of extracellular citrulline markedly increased in rats given a mild footshock paired with tone. The presentation of the tone previously paired with footshock (the conditioned fear response) produced a "conditioned" rise of extracellular citrulline levels in the N.Acc which was attenuated by intraaccumbal infusion of 100 microM SCH-23390, a dopamine D1 receptor antagonist, and prevented by intraaccumbal infusion of 500 microM 7-nitroindazole. The results suggest that in the N.Acc, the dopamine D1 receptors might regulate the neuronal NO synthase activity; this dopamine-dependent mechanism seems to participate in activation of the neuronal NO synthase and probably NO formation in this brain area during the conditioned fear response.

  7. Pdlim7 Regulates Arf6-Dependent Actin Dynamics and Is Required for Platelet-Mediated Thrombosis in Mice.

    Directory of Open Access Journals (Sweden)

    Alexander E Urban

    Full Text Available Upon vessel injury, platelets become activated and rapidly reorganize their actin cytoskeleton to adhere to the site of endothelial damage, triggering the formation of a fibrin-rich plug to prevent further blood loss. Inactivation of Pdlim7 provides the new perspective that regulation of actin cytoskeletal changes in platelets is dependent on the encoded PDZ-LIM protein. Loss-of-function of Pdlim7 triggers hypercoagulopathy and causes significant perinatal lethality in mice. Our in vivo and in vitro studies reveal that Pdlim7 is dynamically distributed along actin fibers, and lack of Pdlim7 leads to a marked inability to rearrange the actin cytoskeleton. Specifically, the absence of Pdlim7 prevents platelets from bundling actin fibers into a concentric ring that defines the round spread shape of activated platelets. Similarly, in mouse embryonic fibroblasts, loss of Pdlim7 abolishes the formation of stress fibers needed to adopt the typical elongated fibroblast shape. In addition to revealing a fundamental cell biological role in actin cytoskeletal organization, we also demonstrate a function of Pdlim7 in regulating the cycling between the GTP/GDP-bound states of Arf6. The small GTPase Arf6 is an essential factor required for actin dynamics, cytoskeletal rearrangements, and platelet activation. Consistent with our findings of significantly elevated initial F-actin ratios and subsequent morphological aberrations, loss of Pdlim7 causes a shift in balance towards an increased Arf6-GTP level in resting platelets. These findings identify a new Pdlim7-Arf6 axis controlling actin dynamics and implicate Pdlim7 as a primary endogenous regulator of platelet-dependent hemostasis.

  8. Genetic regulation by NLA and microRNA827 for maintaining nitrate-dependent phosphate homeostasis in arabidopsis.

    Directory of Open Access Journals (Sweden)

    Surya Kant

    2011-03-01

    Full Text Available Plants need abundant nitrogen and phosphorus for higher yield. Improving plant genetics for higher nitrogen and phosphorus use efficiency would save potentially billions of dollars annually on fertilizers and reduce global environmental pollution. This will require knowledge of molecular regulators for maintaining homeostasis of these nutrients in plants. Previously, we reported that the NITROGEN LIMITATION ADAPTATION (NLA gene is involved in adaptive responses to low-nitrogen conditions in Arabidopsis, where nla mutant plants display abrupt early senescence. To understand the molecular mechanisms underlying NLA function, two suppressors of the nla mutation were isolated that recover the nla mutant phenotype to wild type. Map-based cloning identified these suppressors as the phosphate (Pi transport-related genes PHF1 and PHT1.1. In addition, NLA expression is shown to be regulated by the low-Pi induced microRNA miR827. Pi analysis revealed that the early senescence in nla mutant plants was due to Pi toxicity. These plants accumulated over five times the normal Pi content in shoots specifically under low nitrate and high Pi but not under high nitrate conditions. Also the Pi overaccumulator pho2 mutant shows Pi toxicity in a nitrate-dependent manner similar to the nla mutant. Further, the nitrate and Pi levels are shown to have an antagonistic crosstalk as displayed by their differential effects on flowering time. The results demonstrate that NLA and miR827 have pivotal roles in regulating Pi homeostasis in plants in a nitrate-dependent fashion.

  9. Adenosine: an activity-dependent axonal signal regulating MAP kinase and proliferation in developing Schwann cells.

    Science.gov (United States)

    Stevens, Beth; Ishibashi, Tomoko; Chen, Jiang-Fan; Fields, R Douglas

    2004-02-01

    Nonsynaptic release of ATP from electrically stimulated dorsal root gangion (DRG) axons inhibits Schwann cell (SC) proliferation and arrests SC development at the premyelinating stage, but the specific types of purinergic receptor(s) and intracellular signaling pathways involved in this form of neuron-glia communication are not known. Recent research shows that adenosine is a neuron-glial transmitter between axons and myelinating glia of the CNS. The present study investigates the possibility that adenosine might have a similar function in communicating between axons and premyelinating SCs. Using a combination of pharmacological and molecular approaches, we found that mouse SCs in culture express functional adenosine receptors and ATP receptors, a far more complex array of purinergic receptors than thought previously. Adenosine, but not ATP, activates ERK/MAPK through stimulation of cAMP-linked A2(A) adenosine receptors. Both ATP and adenosine inhibit proliferation of SCs induced by platelet-derived growth factor (PDGF), via mechanisms that are partly independent. In contrast to ATP, adenosine failed to inhibit the differentiation of SCs to the O4+ stage. This indicates that, in addition to ATP, adenosine is an activity-dependent signaling molecule between axons and premyelinating Schwann cells, but that electrical activity, acting through adenosine, has opposite effects on the differentiation of myelinating glia in the PNS and CNS.

  10. Amygdala-dependent fear is regulated by Oprl1 in mice and humans with PTSD.

    Science.gov (United States)

    Andero, Raül; Brothers, Shaun P; Jovanovic, Tanja; Chen, Yen T; Salah-Uddin, Hasib; Cameron, Michael; Bannister, Thomas D; Almli, Lynn; Stevens, Jennifer S; Bradley, Bekh; Binder, Elisabeth B; Wahlestedt, Claes; Ressler, Kerry J

    2013-06-05

    The amygdala-dependent molecular mechanisms driving the onset and persistence of posttraumatic stress disorder (PTSD) are poorly understood. Recent observational studies have suggested that opioid analgesia in the aftermath of trauma may decrease the development of PTSD. Using a mouse model of dysregulated fear, we found altered expression within the amygdala of the Oprl1 gene (opioid receptor-like 1), which encodes the amygdala nociceptin (NOP)/orphanin FQ receptor (NOP-R). Systemic and central amygdala infusion of SR-8993, a new highly selective NOP-R agonist, impaired fear memory consolidation. In humans, a single-nucleotide polymorphism (SNP) within OPRL1 is associated with a self-reported history of childhood trauma and PTSD symptoms (n = 1847) after a traumatic event. This SNP is also associated with physiological startle measures of fear discrimination and magnetic resonance imaging analysis of amygdala-insula functional connectivity. Together, these data suggest that Oprl1 is associated with amygdala function, fear processing, and PTSD symptoms. Further, our data suggest that activation of the Oprl1/NOP receptor may interfere with fear memory consolidation, with implications for prevention of PTSD after a traumatic event.

  11. Calcium-dependent regulation of SNARE-mediated membrane fusion by calmodulin.

    Science.gov (United States)

    Di Giovanni, Jerome; Iborra, Cécile; Maulet, Yves; Lévêque, Christian; El Far, Oussama; Seagar, Michael

    2010-07-30

    Neuroexocytosis requires SNARE proteins, which assemble into trans complexes at the synaptic vesicle/plasma membrane interface and mediate bilayer fusion. Ca(2+) sensitivity is thought to be conferred by synaptotagmin, although the ubiquitous Ca(2+)-effector calmodulin has also been implicated in SNARE-dependent membrane fusion. To examine the molecular mechanisms involved, we examined the direct action of calmodulin and synaptotagmin in vitro, using fluorescence resonance energy transfer to assay lipid mixing between target- and vesicle-SNARE liposomes. Ca(2+)/calmodulin inhibited SNARE assembly and membrane fusion by binding to two distinct motifs located in the membrane-proximal regions of VAMP2 (K(D) = 500 nm) and syntaxin 1 (K(D) = 2 microm). In contrast, fusion was increased by full-length synaptotagmin 1 anchored in vesicle-SNARE liposomes. When synaptotagmin and calmodulin were combined, synaptotagmin overcame the inhibitory effects of calmodulin. Furthermore, synaptotagmin displaced calmodulin binding to target-SNAREs. These findings suggest that two distinct Ca(2+) sensors act antagonistically in SNARE-mediated fusion.

  12. Cytosolic NADP(+)-dependent isocitrate dehydrogenase regulates cadmium-induced apoptosis.

    Science.gov (United States)

    Shin, Seoung Woo; Kil, In Sup; Park, Jeen-Woo

    2010-04-01

    Cadmium ions have a high affinity for thiol groups. Therefore, they may disturb many cellular functions. We recently reported that cytosolic NADP(+)-dependent isocitrate dehydrogenase (IDPc) functions as an antioxidant enzyme to supply NADPH, a major source of reducing equivalents to the cytosol. Cadmium decreased the activity of IDPc both as a purified enzyme and in cultured cells. In the present study, we demonstrate that the knockdown of IDPc expression in HEK293 cells greatly enhances apoptosis induced by cadmium. Transfection of HEK293 cells with an IDPc small interfering RNA significantly decreased the activity of IDPc and enhanced cellular susceptibility to cadmium-induced apoptosis as indicated by the morphological evidence of apoptosis, DNA fragmentation and condensation, cellular redox status, mitochondria redox status and function, and the modulation of apoptotic marker proteins. Taken together, our results suggest that suppressing the expression of IDPc enhances cadmium-induced apoptosis of HEK293 cells by increasing disruption of the cellular redox status. Copyright 2009 Elsevier Inc. All rights reserved.

  13. The aPKC-CBP Pathway Regulates Adult Hippocampal Neurogenesis in an Age-Dependent Manner

    Directory of Open Access Journals (Sweden)

    Ayden Gouveia

    2016-10-01

    Full Text Available While epigenetic modifications have emerged as attractive substrates to integrate environmental changes into the determination of cell identity and function, specific signals that directly activate these epigenetic modifications remain unknown. Here, we examine the role of atypical protein kinase C (aPKC-mediated Ser436 phosphorylation of CBP, a histone acetyltransferase, in adult hippocampal neurogenesis and memory. Using a knockin mouse strain (CbpS436A in which the aPKC-CBP pathway is deficient, we observe impaired hippocampal neuronal differentiation, maturation, and memory and diminished binding of CBP to CREB in 6-month-old CbpS436A mice, but not at 3 months of age. Importantly, elevation of CREB activity rescues these deficits, and CREB activity is reduced whereas aPKC activity is increased in the murine hippocampus as they age from 3 to 6 months regardless of genotype. Thus, the aPKC-CBP pathway is a homeostatic compensatory mechanism that modulates hippocampal neurogenesis and memory in an age-dependent manner in response to reduced CREB activity.

  14. GATA-dependent regulation of TPO-induced c-mpl gene expression during megakaryopoiesis.

    Science.gov (United States)

    Sunohara, Masataka; Morikawa, Shigeru; Fuse, Akira; Sato, Iwao

    2014-01-01

    Thrombopoietin (TPO) and its receptor, c-Mpl, play the crucial role during megakaryocytopoiesis. Previously, we have shown that the promoter activity of c-mpl induced by TPO is modulated by transcription through a PKC-dependent pathway and that GATA(-77) is involved as a positive regulatory element in TPO-induced c-mpl gene expression in the megakaryoblastic CMK cells. In this research, to examine participating possibility of GATA promoter element in TPO- induced c-mpl gene expression through a PKC-independent pathway, the promoter activity of site-directed mutagenesis and the effect of potein kinase C modulator were measured by a transient transfection assay system. Together with our previous results on the TPO-induced c-mpl promoter, this study indicates destruction of -77GATA in c-mpl promoter decreased the activity by 47.3% under existence of GF109203. These results suggest that GATA promoter element plays significant role in TPO-induced c-mpl gene expression through a PKC-independent pathway.

  15. Regulation of KV channel voltage-dependent activation by transmembrane β subunits

    Directory of Open Access Journals (Sweden)

    Xiaohui eSun

    2012-04-01

    Full Text Available Voltage-activated K+ (KV channels are important for shaping action potentials and maintaining resting membrane potential in excitable cells. KV channels contain a central pore-gate domain (PGD surrounded by four voltage-sensing domains (VSD. The VSDs will change conformation in response to alterations of the membrane potential thereby inducing the opening of the PGD. Many KV channels are heteromeric protein complexes containing auxiliary β subunits. These β subunits modulate channel expression and activity to increase functional diversity and render tissue specific phenotypes. This review focuses on the KV β subunits that contain transmembrane (TM segments including the KCNE family and the β subunits of large conductance, Ca2+- and voltage-activated K+ (BK channels. These TM β subunits affect the voltage-dependent activation of KV α subunits. Experimental and computational studies have described the structural location of these β subunits in the channel complexes and the biophysical effects on VSD activation, PGD opening and VSD-PGD coupling. These results reveal some common characteristics and mechanistic insights into KV channel modulation by TM β subunits.

  16. Drosophila Polo regulates the spindle assembly checkpoint through Mps1-dependent BubR1 phosphorylation.

    Science.gov (United States)

    Conde, Carlos; Osswald, Mariana; Barbosa, João; Moutinho-Santos, Tatiana; Pinheiro, Diana; Guimarães, Sofia; Matos, Irina; Maiato, Helder; Sunkel, Claudio E

    2013-06-12

    Maintenance of genomic stability during eukaryotic cell division relies on the spindle assembly checkpoint (SAC) that prevents mitotic exit until all chromosomes are properly attached to the spindle. Polo is a mitotic kinase proposed to be involved in SAC function, but its role has remained elusive. We demonstrate that Polo and Aurora B functional interdependency comprises a positive feedback loop that promotes Mps1 kinetochore localization and activity. Expression of constitutively active Polo restores normal Mps1 kinetochore levels even after Aurora B inhibition, highlighting a role for Polo in Mps1 recruitment to unattached kinetochores downstream of Aurora B. We also show that Mps1 kinetochore localization is required for BubR1 hyperphosphorylation and formation of the 3F3/2 phosphoepitope. This is essential to allow recruitment of Cdc20 to unattached kinetochores and the assembly of anaphase-promoting complex/cyclosome-inhibitory complexes to levels that ensure long-term SAC activity. We propose a model in which Polo controls Mps1-dependent BubR1 phosphorylation to promote Cdc20 kinetochore recruitment and sustained SAC function.

  17. Angiomodulin is a specific marker of vasculature and regulates VEGF-A dependent neo-angiogenesis

    Science.gov (United States)

    Hooper, Andrea T.; Shmelkov, Sergey V.; Gupta, Sunny; Milde, Till; Bambino, Kathryn; Gillen, Kelly; Goetz, Mollie; Chavala, Sai; Baljevic, Muhamed; Murphy, Andrew J.; Valenzuela, David M.; Gale, Nicholas W.; Thurston, Gavin; Yancopoulos, George D.; Vahdat, Linda; Evans, Todd; Rafii, Shahin

    2010-01-01

    Blood vessel formation is controlled by the balance between pro- and anti-angiogenic pathways. Although much is known about the factors that drive sprouting of neovessels, the factors that stabilize and pattern neovessels are undefined. The expression of angiomodulin (AGM), a VEGF-A binding protein, was increased in the vasculature of several human tumors as compared to normal tissue, raising the hypothesis that AGM may modulate VEGF-A-dependent vascular patterning. To elucidate the expression pattern of AGM, we developed an AGM knockin reporter mouse (AGMlacZ/+) wherein we demonstrate that AGM is predominantly expressed in the vasculature of developing embryos and adult organs. During physiological and pathological angiogenesis, AGM is upregulated in the angiogenic vasculature. Using the zebrafish model, we found that AGM is restricted to developing vasculature by 17-22 hpf. Blockade of AGM activity with morpholino oligomers (MO) results in prominent angiogenesis defects in vascular sprouting and remodeling. Concurrent knockdown of both AGM and VEGF-A results in synergistic angiogenesis defects. When VEGF-A is overexpressed, the compensatory induction of the VEGF-A receptor, VEGFR-2/flk-1, is blocked by the simultaneous injection of AGM MO. These results demonstrate that the vascular-specific marker AGM modulates vascular remodeling in part by temporizing the pro-angiogenic effects of VEGF-A. PMID:19542015

  18. Phosphorylation of plasma membrane aquaporin regulates temperature-dependent opening of tulip petals.

    Science.gov (United States)

    Azad, Abul Kalam; Sawa, Yoshihiro; Ishikawa, Takahiro; Shibata, Hitoshi

    2004-05-01

    The opening and closing of tulip petals was reproduced in the dark by changing the temperature from 5 degrees C to 20 degrees C for opening and 20 degrees C to 5 degrees C for closing. The opening process was accompanied by (3)H(2)O transport through the stem from the incubation medium to the petals. A Ca(2+)-channel blocker and a Ca(2+)-chelator inhibited petal opening and (3)H(2)O transport. Several proteins in the isolated plasma membrane fraction were phosphorylated in the presence of 25 micro M Ca(2+) at 20 degrees C. The 31-kDa protein that was phosphorylated, was suggested immunologically as the putative plasma membrane aquaporin (PM-AQP). This phosphorylated PM-AQP clearly reacted with the anti-phospho-Ser. In-gel assay revealed the presence of a 45-kDa Ca(2+)-dependent protein kinase in the isolated plasma membrane. Phosphorylation of the putative PM-AQP was thought to activate the water channel composed of PM-AQP. Dephosphorylation of the phosphorylated PM-AQP was also observed during petal closing at 5 degrees C, suggesting the inactivation of the water channel.

  19. Transforming growth factor beta 1 dependent regulation of Tenascin-C in radiation impaired wound healing

    International Nuclear Information System (INIS)

    Wehrhan, Falk; Roedel, Franz; Grabenbauer, Gerhard G.; Amann, Kerstin; Brueckl, Wolfgang; Schultze-Mosgau, Stefan

    2004-01-01

    Background: Following preoperative radiotherapy prior to ablative surgery of squamous epithelial cell carcinomas of the head and neck region fibrocontractive wound healing disorders occur. Tenascin-C is significantly increased in fibrotic tissue conditions and can be stimulated by the transcription factor NFκB p65. Previous studies showed a reduction of irradiation induced fibrosis during the wound healing process by anti-TGFβ 1 -treatment. The aim of the study was to clarify the question whether Tenascin-C expression is elevated in radiation impaired wounds and whether anti-TGFβ 1 -treatment is capable to influence Tenascin-C and NFκB expression. Material and methods: Wistar rats (male, weight 300-500 g) underwent preoperative irradiation of the head and neck region with 40 Gy, fractionated four times 10 Gy (16 animals), whereas 8 non-irradiated animals served as a control. Four weeks after irradiation a free myocutaneous gracilis flap taken from the groin was transplanted to the neck. Eight animals additionally received 5 μg anti-TGFβ 1 into the graft bed by intradermal injection prior to each fraction of irradiation and on days 1-7 post-operation. On day 14 and 28 following surgery immunohistochemistry (ABC-POX method) was performed assessing the cytoplasmic NFκB and Tenascin-C staining in the transition area between transplant and graft bed. For quantitative considerations the labeling index (ratio: positive cells/total cells) was determined. Results: A significantly altered expression of Tenascin-C in the preirradiated tissue was observed following anti-TGFβ 1 -treatment. NFκB protein was upregulated in irradiated animals and was significantly reduced in the anti-TGFβ 1 treated group on day 28 after transplantation. Conclusions: Tenascin-C expression is prolonged in irradiated animals as compared to non-irradiated tissue. Tenascin-C seems to be regulated by TGFβ 1 as the application of TGFβ 1 -neutralizing antibodies reduces Tenascin-C expression

  20. Aging-dependent changes in rat heart mitochondrial glutaredoxins—Implications for redox regulation

    Directory of Open Access Journals (Sweden)

    Xing-Huang Gao

    2013-01-01

    Full Text Available Clinical and animal studies have documented that hearts of the elderly are more susceptible to ischemia/reperfusion damage compared to young adults. Recently we found that aging-dependent increase in susceptibility of cardiomyocytes to apoptosis was attributable to decrease in cytosolic glutaredoxin 1 (Grx1 and concomitant decrease in NF-κB-mediated expression of anti-apoptotic proteins. Besides primary localization in the cytosol, Grx1 also exists in the mitochondrial intermembrane space (IMS. In contrast, Grx2 is confined to the mitochondrial matrix. Here we report that Grx1 is decreased by 50–60% in the IMS, but Grx2 is increased by 1.4–2.6 fold in the matrix of heart mitochondria from elderly rats. Determination of in situ activities of the Grx isozymes from both subsarcolemmal (SSM and interfibrillar (IFM mitochondria revealed that Grx1 was fully active in the IMS. However, Grx2 was mostly in an inactive form in the matrix, consistent with reversible sequestration of the active-site cysteines of two Grx2 molecules in complex with an iron–sulfur cluster. Our quantitative evaluations of the active/inactive ratio for Grx2 suggest that levels of dimeric Grx2 complex with iron–sulfur clusters are increased in SSM and IFM in the hearts of elderly rats. We found that the inactive Grx2 can be fully reactivated by sodium dithionite or exogenous superoxide production mediated by xanthine oxidase. However, treatment with rotenone, which generates intramitochondrial superoxide through inhibition of mitochondrial respiratory chain Complex I, did not lead to Grx2 activation. These findings suggest that insufficient ROS accumulates in the vicinity of dimeric Grx2 to activate it in situ.

  1. Oxidative phosphorylation-dependent regulation of cancer cell apoptosis in response to anticancer agents.

    Science.gov (United States)

    Yadav, N; Kumar, S; Marlowe, T; Chaudhary, A K; Kumar, R; Wang, J; O'Malley, J; Boland, P M; Jayanthi, S; Kumar, T K S; Yadava, N; Chandra, D

    2015-11-05

    Cancer cells tend to develop resistance to various types of anticancer agents, whether they adopt similar or distinct mechanisms to evade cell death in response to a broad spectrum of cancer therapeutics is not fully defined. Current study concludes that DNA-damaging agents (etoposide and doxorubicin), ER stressor (thapsigargin), and histone deacetylase inhibitor (apicidin) target oxidative phosphorylation (OXPHOS) for apoptosis induction, whereas other anticancer agents including staurosporine, taxol, and sorafenib induce apoptosis in an OXPHOS-independent manner. DNA-damaging agents promoted mitochondrial biogenesis accompanied by increased accumulation of cellular and mitochondrial ROS, mitochondrial protein-folding machinery, and mitochondrial unfolded protein response. Induction of mitochondrial biogenesis occurred in a caspase activation-independent mechanism but was reduced by autophagy inhibition and p53-deficiency. Abrogation of complex-I blocked DNA-damage-induced caspase activation and apoptosis, whereas inhibition of complex-II or a combined deficiency of OXPHOS complexes I, III, IV, and V due to impaired mitochondrial protein synthesis did not modulate caspase activity. Mechanistic analysis revealed that inhibition of caspase activation in response to anticancer agents associates with decreased release of mitochondrial cytochrome c in complex-I-deficient cells compared with wild type (WT) cells. Gross OXPHOS deficiencies promoted increased release of apoptosis-inducing factor from mitochondria compared with WT or complex-I-deficient cells, suggesting that cells harboring defective OXPHOS trigger caspase-dependent as well as caspase-independent apoptosis in response to anticancer agents. Interestingly, DNA-damaging agent doxorubicin showed strong binding to mitochondria, which was disrupted by complex-I-deficiency but not by complex-II-deficiency. Thapsigargin-induced caspase activation was reduced upon abrogation of complex-I or gross OXPHOS deficiency

  2. Nitric oxide regulates input specificity of long-term depression and context dependence of cerebellar learning.

    Directory of Open Access Journals (Sweden)

    Hideaki Ogasawara

    2007-01-01

    Full Text Available Recent studies have shown that multiple internal models are acquired in the cerebellum and that these can be switched under a given context of behavior. It has been proposed that long-term depression (LTD of parallel fiber (PF-Purkinje cell (PC synapses forms the cellular basis of cerebellar learning, and that the presynaptically synthesized messenger nitric oxide (NO is a crucial "gatekeeper" for LTD. Because NO diffuses freely to neighboring synapses, this volume learning is not input-specific and brings into question the biological significance of LTD as the basic mechanism for efficient supervised learning. To better characterize the role of NO in cerebellar learning, we simulated the sequence of electrophysiological and biochemical events in PF-PC LTD by combining established simulation models of the electrophysiology, calcium dynamics, and signaling pathways of the PC. The results demonstrate that the local NO concentration is critical for induction of LTD and for its input specificity. Pre- and postsynaptic coincident firing is not sufficient for a PF-PC synapse to undergo LTD, and LTD is induced only when a sufficient amount of NO is provided by activation of the surrounding PFs. On the other hand, above-adequate levels of activity in nearby PFs cause accumulation of NO, which also allows LTD in neighboring synapses that were not directly stimulated, ruining input specificity. These findings lead us to propose the hypothesis that NO represents the relevance of a given context and enables context-dependent selection of internal models to be updated. We also predict sparse PF activity in vivo because, otherwise, input specificity would be lost.

  3. Melatonin ameliorates myocardial ischemia reperfusion injury through SIRT3-dependent regulation of oxidative stress and apoptosis.

    Science.gov (United States)

    Zhai, Mengen; Li, Buying; Duan, Weixun; Jing, Lin; Zhang, Bin; Zhang, Meng; Yu, Liming; Liu, Zhenhua; Yu, Bo; Ren, Kai; Gao, Erhe; Yang, Yang; Liang, Hongliang; Jin, Zhenxiao; Yu, Shiqiang

    2017-09-01

    Sirtuins are a family of highly evolutionarily conserved nicotinamide adenine nucleotide-dependent histone deacetylases. Sirtuin-3 (SIRT3) is a member of the sirtuin family that is localized primarily to the mitochondria and protects against oxidative stress-related diseases, including myocardial ischemia/reperfusion (MI/R) injury. Melatonin has a favorable effect in ameliorating MI/R injury. We hypothesized that melatonin protects against MI/R injury by activating the SIRT3 signaling pathway. In this study, mice were pretreated with or without a selective SIRT3 inhibitor and then subjected to MI/R operation. Melatonin was administered intraperitoneally (20 mg/kg) 10 minutes before reperfusion. Melatonin treatment improved postischemic cardiac contractile function, decreased infarct size, diminished lactate dehydrogenase release, reduced the apoptotic index, and ameliorated oxidative damage. Notably, MI/R induced a significant decrease in myocardial SIRT3 expression and activity, whereas the melatonin treatment upregulated SIRT3 expression and activity, and thus decreased the acetylation of superoxide dismutase 2 (SOD2). In addition, melatonin increased Bcl-2 expression and decreased Bax, Caspase-3, and cleaved Caspase-3 levels in response to MI/R. However, the cardioprotective effects of melatonin were largely abolished by the selective SIRT3 inhibitor 3-(1H-1,2,3-triazol-4-yl)pyridine (3-TYP), suggesting that SIRT3 plays an essential role in mediating the cardioprotective effects of melatonin. In vitro studies confirmed that melatonin also protected H9c2 cells against simulated ischemia/reperfusion injury (SIR) by attenuating oxidative stress and apoptosis, while SIRT3-targeted siRNA diminished these effects. Taken together, our results demonstrate for the first time that melatonin treatment ameliorates MI/R injury by reducing oxidative stress and apoptosis via activating the SIRT3 signaling pathway. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons

  4. The phosphorylation-dependent regulation of nuclear SREBP1 during mitosis links lipid metabolism and cell growth

    Science.gov (United States)

    Bengoechea-Alonso, Maria Teresa; Ericsson, Johan

    2016-01-01

    ABSTRACT The SREBP transcription factors are major regulators of lipid metabolism. Disturbances in lipid metabolism are at the core of several health issues facing modern society, including cardiovascular disease, obesity and diabetes. In addition, the role of lipid metabolism in cancer cell growth is receiving increased attention. Transcriptionally active SREBP molecules are unstable and rapidly degraded in a phosphorylation-dependent manner by Fbw7, a ubiquitin ligase that targets several cell cycle regulatory proteins for degradation. We have previously demonstrated that active SREBP1 is stabilized during mitosis. We have now delineated the mechanisms involved in the stabilization of SREBP1 in mitotic cells. This process is initiated by the phosphorylation of a specific serine residue in nuclear SREBP1 by the mitotic kinase Cdk1. The phosphorylation of this residue creates a docking site for a separate mitotic kinase, Plk1. Plk1 interacts with nuclear SREBP1 in mitotic cells and phosphorylates a number of residues in the C-terminal domain of the protein, including a threonine residue in close proximity of the Fbw7 docking site in SREBP1. The phosphorylation of these residues by Plk1 blocks the interaction between SREBP1 and Fbw7 and attenuates the Fbw7-dependent degradation of nuclear SREBP1 during cell division. Inactivation of SREBP1 results in a mitotic defect, suggesting that SREBP1 could regulate cell division. We propose that the mitotic phosphorylation and stabilization of nuclear SREBP1 during cell division provides a link between lipid metabolism and cell proliferation. Thus, the current study provides additional support for the emerging hypothesis that SREBP-dependent lipid metabolism may be important for cell growth. PMID:27579997

  5. Photoperiod- and Triiodothyronine-dependent Regulation of Reproductive Neuropeptides, Proinflammatory Cytokines, and Peripheral Physiology in Siberian Hamsters (Phodopus sungorus).

    Science.gov (United States)

    Banks, Ruth; Delibegovic, Mirela; Stevenson, Tyler J

    2016-06-01

    Seasonal trade-offs in reproduction and immunity are ubiquitous in nature. The mechanisms that govern transitions across seasonal physiological states appear to involve reciprocal switches in the local synthesis of thyroid hormone. In long-day (LD) summer-like conditions, increased hypothalamic triiodothyronine (T3) stimulates gonadal development. Alternatively, short-day (SD) winter-like conditions increase peripheral leukocytes and enhance multiple aspects of immune function. These data indicate that the localized effects of T3 in the hypothalamus and leukocytes are photoperiod dependent. We tested the hypothesis that increased peripheral T3 in SD conditions would increase aspects of reproductive physiology and inhibit immune function, whereas T3 injections in LD conditions would facilitate aspects of immune function (i.e., leukocytes). In addition, we also examined whether T3 regulates hypothalamic neuropeptide expression as well as hypothalamic and splenic proinflammatory cytokine expression. Adult male Siberian hamsters were maintained in LD (15L:9D) or transferred to SD (9L:15D) for 8 weeks. A subset of LD and SD hamsters was treated daily with 5 µg T3 for 2 weeks. LD and SD controls were injected with saline. Daily T3 administration in SD hamsters (SD+T3) resulted in a rapid and substantial decrease in peripheral leukocyte concentrations and stimulated gonadal development. T3 treatment in LD (LD+T3) had no effect on testicular volumes but significantly increased leukocyte concentrations. Molecular analyses revealed that T3 stimulated interleukin 1β messenger RNA (mRNA) expression in the spleen and inhibited RFamide Related Peptide-3 mRNA expression in the hypothalamus. Moreover, there was a photoperiod-dependent decrease in splenic tumor necrosis factor-α mRNA expression. These findings reveal that T3 has tissue-specific and photoperiod-dependent regulation of seasonal rhythms in reproduction and immune function. © 2016 The Author(s).

  6. Variation in regulator of G-protein signaling 17 gene (RGS17 is associated with multiple substance dependence diagnoses

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    Zhang Huiping

    2012-05-01

    Full Text Available Abstract Background RGS17 and RGS20 encode two members of the regulator of G-protein signaling RGS-Rz subfamily. Variation in these genes may alter their transcription and thereby influence the function of G protein-coupled receptors, including opioid receptors, and modify risk for substance dependence. Methods The association of 13 RGS17 and eight RGS20 tag single nucleotide polymorphisms (SNPs was examined with four substance dependence diagnoses (alcohol (AD, cocaine (CD, opioid (OD or marijuana (MjD] in 1,905 African Americans (AAs: 1,562 cases and 343 controls and 1,332 European Americans (EAs: 981 cases and 351 controls. Analyses were performed using both χ2 tests and logistic regression analyses that covaried sex, age, and ancestry proportion. Correlation of genotypes and mRNA expression levels was assessed by linear regression analyses. Results Seven RGS17 SNPs showed a significant association with at least one of the four dependence traits after a permutation-based correction for multiple testing (0.003≤Pempirical≤0.037. The G allele of SNP rs596359, in the RGS17 promoter region, was associated with AD, CD, OD, or MjD in both populations (0.005≤Pempirical≤0.019. This allele was also associated with significantly lower mRNA expression levels of RGS17 in YRI subjects (P = 0.002 and non-significantly lower mRNA expression levels of RGS17 in CEU subjects (P = 0.185. No RGS20 SNPs were associated with any of the four dependence traits in either population. Conclusions This study demonstrated that variation in RGS17 was associated with risk for substance dependence diagnoses in both AA and EA populations.

  7. Calcium-mediated signaling and calmodulin-dependent kinase regulate hepatocyte-inducible nitric oxide synthase expression.

    Science.gov (United States)

    Zhang, Baochun; Crankshaw, Will; Nesemeier, Ryan; Patel, Jay; Nweze, Ikenna; Lakshmanan, Jaganathan; Harbrecht, Brian G

    2015-02-01

    Induced nitric oxide synthase (iNOS) is induced in hepatocytes by shock and inflammatory stimuli. Excessive NO from iNOS mediates shock-induced hepatic injury and death, so understanding the regulation of iNOS will help elucidate the pathophysiology of septic shock. In vitro, cytokines induce iNOS expression through activation of signaling pathways including mitogen-activated protein kinases and nuclear factor κB. Cytokines also induce calcium (Ca(2+)) mobilization and activate calcium-mediated intracellular signaling pathways, typically through activation of calmodulin-dependent kinases (CaMK). Calcium regulates NO production in macrophages but the role of calcium and calcium-mediated signaling in hepatocyte iNOS expression has not been defined. Primary rat hepatocytes were isolated, cultured, and induced to produce NO with proinflammatory cytokines. Calcium mobilization and Ca(2+)-mediated signaling were altered with ionophore, Ca(2+) channel blockers, and inhibitors of CaMK. The Ca(2+) ionophore A23187 suppressed cytokine-stimulated NO production, whereas Ethylene glycol tetraacetic acid and nifedipine increased NO production, iNOS messenger RNA, and iNOS protein expression. Inhibition of CaMK with KN93 and CBD increased NO production but the calcineurin inhibitor FK 506 decreased iNOS expression. These data demonstrate that calcium-mediated signaling regulates hepatocyte iNOS expression and does so through a mechanism independent of calcineurin. Changes in intracellular calcium levels may regulate iNOS expression during hepatic inflammation induced by proinflammatory cytokines. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Mechanistic and Structural Insights Into the Unique TetR-Dependent Regulation of a Drug Efflux Pump in Mycobacterium abscessus.

    Science.gov (United States)

    Richard, Matthias; Gutiérrez, Ana Victoria; Viljoen, Albertus J; Ghigo, Eric; Blaise, Mickael; Kremer, Laurent

    2018-01-01

    Mycobacterium abscessus is an emerging human pathogen causing severe pulmonary infections and is refractory to standard antibiotherapy, yet few drug resistance mechanisms have been reported in this organism. Recently, mutations in MAB_4384 leading to up-regulation of the MmpS5/MmpL5 efflux pump were linked to increased resistance to thiacetazone derivatives. Herein, the DNA-binding activity of MAB_4384 was investigated by electrophoretic mobility shift assays using the palindromic sequence IR S5/L5 located upstream of mmpS5/mmpL5 . Introduction of point mutations within IR S5/L5 identified the sequence requirements for optimal binding of the regulator. Moreover, formation of the protein/IR S5/L5 complex was severely impaired for MAB_4384 harboring D14N or F57L substitutions. IR S5/L5 /lacZ reporter fusions in M. abscessus demonstrated increased β-galactosidase activity either in strains lacking a functional MAB_4384 or in cultures treated with the TAC analogs. In addition, X-ray crystallography confirmed a typical TetR homodimeric structure of MAB_4384 and unraveled a putative ligand binding site in which the analogs could be docked. Overall, these results support drug recognition of the MAB_4384 TetR regulator, alleviating its binding to IR S5/L5 and steering up-regulation of MmpS5/MmpL5. This study provides new mechanistic and structural details of TetR-dependent regulatory mechanisms of efflux pumps and drug resistance in mycobacteria.

  9. Onset and organ specificity of Tk2 deficiency depends on Tk1 down-regulation and transcriptional compensation.

    Science.gov (United States)

    Dorado, Beatriz; Area, Estela; Akman, Hasan O; Hirano, Michio

    2011-01-01

    Deficiency of thymidine kinase 2 (TK2) is a frequent cause of isolated myopathy or encephalomyopathy in children with mitochondrial DNA (mtDNA) depletion. To determine the bases of disease onset, organ specificity and severity of TK2 deficiency, we have carefully characterized Tk2 H126N knockin mice (Tk2-/-). Although normal until postnatal day 8, Tk2-/- mice rapidly develop fatal encephalomyopathy between postnatal days 10 and 13. We have observed that wild-type Tk2 activity is constant in the second week of life, while Tk1 activity decreases significantly between postnatal days 8 and 13. The down-regulation of Tk1 activity unmasks Tk2 deficiency in Tk2-/- mice and correlates with the onset of mtDNA depletion in the brain and the heart. Resistance to pathology in Tk2 mutant organs depends on compensatory mechanisms to the reduced mtDNA level. Our analyses at postnatal day 13 have revealed that Tk2-/- heart significantly increases mitochondrial transcript levels relative to the mtDNA content. This transcriptional compensation allows the heart to maintain normal levels of mtDNA-encoded proteins. The up-regulation in mitochondrial transcripts is not due to increased expression of the master mitochondrial biogenesis regulators peroxisome proliferator-activated receptor-gamma coactivator 1 alpha and nuclear respiratory factors 1 and 2, or to enhanced expression of the mitochondrial transcription factors A, B1 or B2. Instead, Tk2-/- heart compensates for mtDNA depletion by down-regulating the expression of the mitochondrial transcriptional terminator transcription factor 3 (MTERF3). Understanding the molecular mechanisms that allow Tk2 mutant organs to be spared may help design therapies for Tk2 deficiency.

  10. Up-regulation of endothelial monocyte chemoattractant protein-1 by coplanar PCB77 is caveolin-1-dependent

    International Nuclear Information System (INIS)

    Majkova, Zuzana; Smart, Eric; Toborek, Michal; Hennig, Bernhard

    2009-01-01

    Atherosclerosis, the primary cause of heart disease and stroke is initiated in the vascular endothelium, and risk factors for its development include environmental exposure to persistent organic pollutants. Caveolae are membrane microdomains involved in regulation of many signaling pathways, and in particular in endothelial cells. We tested the hypothesis that intact caveolae are required for coplanar PCB77-induced up-regulation of monocyte chemoattractant protein-1 (MCP-1), an endothelium-derived chemokine that attracts monocytes into sub-endothelial space in early stages of the atherosclerosis development. Atherosclerosis-prone LDL-R -/- mice (control) or caveolin-1 -/- /LDL-R -/- mice were treated with PCB77. PCB77 induced aortic mRNA expression and plasma protein levels of MCP-1 in control, but not caveolin-1 -/- /LDL-R -/- mice. To study the mechanism of this effect, primary endothelial cells were used. PCB77 increased MCP-1 levels in endothelial cells in a time- and concentration-dependent manner. This effect was abolished by caveolin-1 silencing using siRNA. Also, MCP-1 up-regulation by PCB77 was prevented by inhibiting p38 and c-Jun N-terminal kinase (JNK), but not ERK1/2, suggesting regulatory functions via p38 and JNK MAPK pathways. Finally, pre-treatment of endothelial cells with the aryl hydrocarbon receptor (AhR) inhibitor α-naphthoflavone (α-NF) partially blocked MCP-1 up-regulation. Thus, our data demonstrate that coplanar PCB77 can induce MCP-1 expression by endothelial cells and that this effect is mediated by AhR, as well as p 38 and JNK MAPK pathways. Intact caveolae are required for these processes both in vivo and in vitro. This further supports a key role for caveolae in vascular inflammation induced by persistent organic pollutants.

  11. Uroguanylin levels in intestine and plasma are regulated by nutritional status in a leptin-dependent manner.

    Science.gov (United States)

    Folgueira, C; Sanchez-Rebordelo, E; Barja-Fernandez, S; Leis, R; Tovar, S; Casanueva, F F; Dieguez, C; Nogueiras, R; Seoane, L M

    2016-03-01

    Uroguanylin (UGN) is a 16 amino acid peptide produced mainly by intestinal epithelial cells. Nutrients intake increases circulating levels of prouroguanylin that is processed and converted to UGN to activate the guanylyl cyclase 2C receptor (GUCY2C). Given that the UGN-GUCY2C system has been proposed as a novel gut-brain endocrine axis regulating energy balance, the aim of the present study was to investigate the regulation of UGN protein levels in duodenum and circulating levels in lean and obese mice under different nutritional conditions and its potential interaction with leptin. Swiss, C57BL/6 wild-type and ob/ob male adult mice under different nutritional conditions were used: fed ad libitum standard diet (control); 48 h fasting (fasted); 48 h fasting followed by 24 h of feeding (refed); and fed high-fat diet (45 %) during 10 weeks. In addition, peripheral leptin administration was performed. Intestinal uroguanylin expression was studied by Western blot analysis; plasma levels were measured by ELISA. Food deprivation significantly reduced plasma UGN levels, which were correlated with the lower protein levels of UGN in duodenum. These effects were reverted after refeeding and leptin challenge. Consistently, in ob/ob mice UGN expression was decreased, whereas leptin treatment up-regulated UGN levels in duodenum in these genetically modified mice compared to WT. Diet-induced obese mice displayed increased UGN levels in intestine and plasma in comparison with lean mice. Our findings suggest that UGN levels are correlated with energy balance status and that the regulation of UGN by nutritional status is leptin-dependent.

  12. Proteomic analysis of growth phase-dependent expression of Legionella pneumophila proteins which involves regulation of bacterial virulence traits.

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Hayashi

    Full Text Available Legionella pneumophila, which is a causative pathogen of Legionnaires' disease, expresses its virulent traits in response to growth conditions. In particular, it is known to become virulent at a post-exponential phase in vitro culture. In this study, we performed a proteomic analysis of differences in expression between the exponential phase and post-exponential phase to identify candidates associated with L. pneumophila virulence using 2-Dimentional Fluorescence Difference Gel Electrophoresis (2D-DIGE combined with Matrix-Assisted Laser Desorption/Ionization-Mass Spectrometry (MALDI-TOF-MS. Of 68 identified proteins that significantly differed in expression between the two growth phases, 64 were up-regulated at a post-exponential phase. The up-regulated proteins included enzymes related to glycolysis, ketone body biogenesis and poly-3-hydroxybutyrate (PHB biogenesis, suggesting that L. pneumophila may utilize sugars and lipids as energy sources, when amino acids become scarce. Proteins related to motility (flagella components and twitching motility-associated proteins were also up-regulated, predicting that they enhance infectivity of the bacteria in host cells under certain conditions. Furthermore, 9 up-regulated proteins of unknown function were found. Two of them were identified as novel bacterial factors associated with hemolysis of sheep red blood cells (SRBCs. Another 2 were found to be translocated into macrophages via the Icm/Dot type IV secretion apparatus as effector candidates in a reporter assay with Bordetella pertussis adenylate cyclase. The study will be helpful for virulent analysis of L. pneumophila from the viewpoint of physiological or metabolic modulation dependent on growth phase.

  13. Activation of liver X receptor decreases atherosclerosis in Ldlr⁻/⁻ mice in the absence of ATP-binding cassette transporters A1 and G1 in myeloid cells.

    Science.gov (United States)

    Kappus, Mojdeh S; Murphy, Andrew J; Abramowicz, Sandra; Ntonga, Vusisizwe; Welch, Carrie L; Tall, Alan R; Westerterp, Marit

    2014-02-01

    Liver X receptor (LXR) activators decrease atherosclerosis in mice. LXR activators (1) directly upregulate genes involved in reverse cholesterol transport and (2) exert anti-inflammatory effects mediated by transrepression of nuclear factor-κB target genes. We investigated whether myeloid cell deficiency of ATP-binding cassette transporters A1 and G1 (ABCA1/G1), principal targets of LXR that promote macrophage cholesterol efflux and initiate reverse cholesterol transport, would abolish the beneficial effects of LXR activation on atherosclerosis. LXR activator T0901317 substantially reduced inflammatory gene expression in macrophages lacking ABCA1/G1. Ldlr(-/-) mice were transplanted with Abca1(-/-)Abcg1(-/-) or wild-type bone marrow (BM) and fed a Western-type diet for 6 weeks with or without T0901317 supplementation. Abca1/g1 BM deficiency increased atherosclerotic lesion complexity and inflammatory cell infiltration into the adventitia and myocardium. T0901317 markedly decreased lesion area, complexity, and inflammatory cell infiltration in the Abca1(-/-)Abcg1(-/-) BM-transplanted mice. To investigate whether this was because of macrophage Abca1/g1 deficiency, Ldlr(-/-) mice were transplanted with LysmCreAbca1(fl/fl)Abcg1(fl/fl) or Abca1(fl/fl)Abcg1(fl/fl) BM and fed Western-type diet with or without the more specific LXR agonist GW3965 for 12 weeks. GW3965 decreased lesion size in both groups, and the decrease was more prominent in the LysmCreAbca1(fl/fl)Abcg1(fl/fl) group. The results suggest that anti-inflammatory effects of LXR activators are of key importance to their antiatherosclerotic effects in vivo independent of cholesterol efflux pathways mediated by macrophage ABCA1/G1. This has implications for the development of LXR activators that lack adverse effects on lipogenic genes while maintaining the ability to transrepress inflammatory genes.

  14. Quantitative analysis of the Ca2+ -dependent regulation of delayed rectifier K+ current IKs in rabbit ventricular myocytes.

    Science.gov (United States)

    Bartos, Daniel C; Morotti, Stefano; Ginsburg, Kenneth S; Grandi, Eleonora; Bers, Donald M

    2017-04-01

    [Ca 2+ ] i enhanced rabbit ventricular slowly activating delayed rectifier K + current (I Ks ) by negatively shifting the voltage dependence of activation and slowing deactivation, similar to perfusion of isoproterenol. Rabbit ventricular rapidly activating delayed rectifier K + current (I Kr ) amplitude and voltage dependence were unaffected by high [Ca 2+ ] i . When measuring or simulating I Ks during an action potential, I Ks was not different during a physiological Ca 2+ transient or when [Ca 2+ ] i was buffered to 500 nm. The slowly activating delayed rectifier K + current (I Ks ) contributes to repolarization of the cardiac action potential (AP). Intracellular Ca 2+ ([Ca 2+ ] i ) and β-adrenergic receptor (β-AR) stimulation modulate I Ks amplitude and kinetics, but details of these important I Ks regulators and their interaction are limited. We assessed the [Ca 2+ ] i dependence of I Ks in steady-state conditions and with dynamically changing membrane potential and [Ca 2+ ] i during an AP. I Ks was recorded from freshly isolated rabbit ventricular myocytes using whole-cell patch clamp. With intracellular pipette solutions that controlled free [Ca 2+ ] i , we found that raising [Ca 2+ ] i from 100 to 600 nm produced similar increases in I Ks as did β-AR activation, and the effects appeared additive. Both β-AR activation and high [Ca 2+ ] i increased maximally activated tail I Ks , negatively shifted the voltage dependence of activation, and slowed deactivation kinetics. These data informed changes in our well-established mathematical model of the rabbit myocyte. In both AP-clamp experiments and simulations, I Ks recorded during a normal physiological Ca 2+ transient was similar to I Ks measured with [Ca 2+ ] i clamped at 500-600 nm. Thus, our study provides novel quantitative data as to how physiological [Ca 2+ ] i regulates I Ks amplitude and kinetics during the normal rabbit AP. Our results suggest that micromolar [Ca 2+ ] i , in the submembrane or

  15. Phosphate regulates chondrogenesis in a biphasic and maturation-dependent manner.

    Science.gov (United States)

    Wu, Biming; Durisin, Emily K; Decker, Joseph T; Ural, Evran E; Shea, Lonnie D; Coleman, Rhima M

    Inorganic phosphate (Pi) has been recognized as an important signaling molecule that modulates chondrocyte maturation and cartilage mineralization. However, conclusive experimental evidence for its involvement in early chondrogenesis is still lacking. Here, using high-density monolayer (2D) and pellet (3D) culture models of chondrogenic ATDC5 cells, we demonstrate that the cell response to Pi does not correlate with the Pi concentration in the culture medium but is better predicted by the availability of Pi on a per cell basis (Pi abundance). Both culture models were treated with ITS+, 10mM β-glycerophosphate (βGP), or ITS+/10mM βGP, which resulted in three levels of Pi abundance in cultures: basal (Pi/DNA 60ng/µg). In chondrogenic medium alone, the abundance levels were at the basal level in 2D culture and moderate in 3D cultures. The addition of 10mM βGP resulted in moderate abundance in 2D and high abundance in 3D cultures. Moderate Pi abundance enhanced early chondrogenesis and production of aggrecan and type II collagen whereas high Pi abundance inhibited chondrogenic differentiation and induced rapid mineralization. Inhibition of sodium phosphate transporters reduced phosphate-induced expression of chondrogenic markers. When 3D ITS+/βGP cultures were treated with levamisole to reduce ALP activity, Pi abundance was decreased to moderate levels, which resulted in significant upregulation of chondrogenic markers, similar to the response in 2D cultures. Delay of phosphate delivery until after early chondrogenesis occurs (7 days) no longer enhanced chondrogenesis, but instead accelerated hypertrophy and mineralization. Together, our data highlights the dependence of chondroprogenitor cell response to Pi on its availability to individual cells and the chondrogenic maturation stage of these cells and suggest that appropriate temporal delivery of phosphate to ATDC5 cells in 3D cultures represents a rapid model for mechanistic studies into the effects of

  16. Regulation of phenylacetic acid uptake is sigma54 dependent in Pseudomonas putida CA-3.

    LENUS (Irish Health Repository)

    O' Leary, Niall D

    2011-10-13

    primer extension analysis. Comparative analyses of genomes encoding phenylacetyl CoA, (PACoA), catabolic operons identified a common association among styrene degradation linked PACoA catabolons in Pseudomonas species studied to date. Conclusions In summary, this is the first study to report RpoN dependent transcriptional activation of the PACoA catabolon paaL gene, encoding a transport protein essential for phenylacetic acid utilisation in P. putida CA-3. Bioinformatic analysis is provided to suggest this regulatory link may be common among styrene degrading Pseudomonads.

  17. A GPBAR1 (TGR5 small molecule agonist shows specific inhibitory effects on myeloid cell activation in vitro and reduces experimental autoimmune encephalitis (EAE in vivo.

    Directory of Open Access Journals (Sweden)

    Nuruddeen D Lewis

    Full Text Available GPBAR1 is a G protein-coupled receptor that is activated by certain bile acids and plays an important role in the regulation of bile acid synthesis, lipid metabolism, and energy homeostasis. Recent evidence suggests that GPBAR1 may also have important effects in reducing the inflammatory response through its expression on monocytes and macrophages. To further understand the role of GPBAR1 in inflammation, we generated a novel, selective, proprietary GPBAR1 agonist and tested its effectiveness at reducing monocyte and macrophage activation in vitro and in vivo. We have used this agonist, together with previously described agonists to study agonism of GPBAR1, and shown that they can all induce cAMP and reduce TLR activation-induced cytokine production in human monocytes and monocyte-derived macrophages in vitro. Additionally, through the usage of RNA sequencing (RNA-Seq, we identified a select set of genes that are regulated by GPBAR1 agonism during LPS activation. To further define the in vivo role of GPBAR1 in inflammation, we assessed GPBAR1 expression and found high levels on circulating mouse monocytes. Agonism of GPBAR1 reduced LPS-induced cytokine production in mouse monocytes ex vivo and serum cytokine levels in vivo. Agonism of GPBAR1 also had profound effects in the experimental autoimmune encephalomyelitis (EAE mouse model of multiple sclerosis, where monocytes play an important role. Mice treated with the GPBAR1 agonist exhibited a significant reduction in the EAE clinical score which correlated with reduced monocyte and microglial activation and reduced trafficking of monocytes and T cells into the CNS. These data confirm the importance of GPBAR1 in controlling monocyte and macrophage activation in vivo and support the rationale for selective agonists of GPBAR1 in the treatment of inflammatory diseases.

  18. Arabidopsis cryptochrome 1 is a soluble protein mediating blue light-dependent regulation of plant growth and development

    International Nuclear Information System (INIS)

    Lin ChenTao; Ahmad, M.; Cashmore, A.R.

    1996-01-01

    Cryptochrome 1 (CRY1) is a flavin-type blue type receptor of Arabidopsis thaliana which mediates inhibition of hypocotyl elongation. In the work described in this report it is demonstrated that CRY1 is a soluble protein expressed in both young seedlings grown either in the dark or under light, and in different organs of adult plants. The functional role of CRY1 was further investigated using transgenic Arabidopsis plants overexpressing CRY1. It is demonstrated that overexpression of CRY1 resulted in hypersensitivity to blue, UV-A, and green light for the inhibition of hypocotyl elongation response. Transgenic plants overexpressing CRY1 also exhibited a dwarf phenotype with reduced size in almost every organ. This was in keeping with the previous observation of reciprocal alterations found in hy4 mutant plants and is consistent with a hypothesis that CRY1 mediates a light-dependent process resulting in a general inhibitory effect on plant growth. In addition, transgenic plants overexpressing CRY1 showed increased anthocyanin accumulation in response to blue, UV-A, and green light in a fluence rate-dependent manner. This increase in anthocyanin accumulation in transgenic plants was shown to be concomitant with increased blue light-induction of CHS gene expression. It is concluded that CRY1 is a photoreceptor mediating blue light-dependent regulation of gene expression in addition to its affect on plant growth. (author)

  19. Bicarbonate/chloride antiport in Vero cells: II. Mechanisms for bicarbonate-dependent regulation of intracellular pH

    International Nuclear Information System (INIS)

    Olsnes, S.; Ludt, J.; Tonnessen, T.I.; Sandvig, K.

    1987-01-01

    The rates of bicarbonate-dependent uptake and efflux of 22 Na + in Vero cells were studied and compared with the uptake and efflux of 36 Cl - . Both processes were strongly inhibited by DIDS. Whereas the transport of chloride increased approximately ten-fold when the internal pH was increased over a narrow range around neutrality, the uptake of Na + was much less affected by changes in pH. The bicarbonate-linked uptake of 22 Na + was dependent on internal Cl- but not on internal Na + . At a constant external concentration of HCO 3 -, the amount of 22 Na + associated with the cells increased when the internal concentration of HCO 3 - decreased and vice versa, which is compatible with the possibility that the ion pair NaCO 3 - is the transported species and that the transport is symmetric across the membrane. Bicarbonate inhibited the uptake of 36 Cl - both in the absence and presence of Na + . At alkaline internal pH, HCO 3 - stimulated the efflux of 36 Cl - from preloaded cells, while at acidic internal pH both Na + and HCO 3 - were required to induce 36 Cl - efflux. We propose a model for how bicarbonate-dependent regulation of the internal pH may occur. This model implies the existence of two bicarbonate transport mechanisms that, under physiological conditions, transport OH(-)-equivalents in opposite directions across the plasma membrane

  20. Aryl hydrocarbon receptor-dependent regulation of miR-196a expression controls lung fibroblast apoptosis but not proliferation

    International Nuclear Information System (INIS)

    Hecht, Emelia; Zago, Michela; Sarill, Miles; Rico de Souza, Angela; Gomez, Alvin; Matthews, Jason; Hamid, Qutayba; Eidelman, David H.; Baglole, Carolyn J.

    2014-01-01

    The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor implicated in the regulation of apoptosis and proliferation. Although activation of the AhR by xenobiotics such as dioxin inhibits the cell cycle and control apoptosis, paradoxically, AhR expression also promotes cell proliferation and survival independent of exogenous ligands. The microRNA (miRNA) miR-196a has also emerged as a regulator of proliferation and apoptosis but a relationship between the AhR and miR-196a is not known. Therefore, we hypothesized that AhR-dependent regulation of endogenous miR-196a expression would promote cell survival and proliferation. Utilizing lung fibroblasts from AhR deficient (AhR −/− ) and wild-type (AhR +/+ ) mice, we show that there is ligand-independent regulation of miRNA, including low miR-196a in AhR −/− cells. Validation by qRT-PCR revealed a significant decrease in basal expression of miR-196a in AhR −/− compared to AhR +/+ cells. Exposure to AhR agonists benzo[a]pyrene (B[a]P) and FICZ as well as AhR antagonist CH-223191 decreased miR-196a expression in AhR +/+ fibroblasts concomitant with decreased AhR protein levels. There was increased proliferation only in AhR +/+ lung fibroblasts in response to serum, corresponding to a decrease in p27 KIP1 protein, a cyclin-dependent kinase inhibitor. Increasing the cellular levels of miR-196a had no effect on proliferation or expression of p27 KIP1 in AhR −/− fibroblasts but attenuated cigarette smoke-induced apoptosis. This study provides the first evidence that AhR expression is essential for the physiological regulation of cellular miRNA levels- including miR-196a. Future experiments designed to elucidate the functional relationship between the AhR and miR-196a may delineate additional novel ligand-independent roles for the AhR. - Highlights: • The AhR controls proliferation and apoptosis in lung cells. • The AhR regulates the expression of the microRNA miR-196a independent of

  1. Aryl hydrocarbon receptor-dependent regulation of miR-196a expression controls lung fibroblast apoptosis but not proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Hecht, Emelia [Department of Medicine, McGill University, Montreal, Quebec (Canada); Zago, Michela [Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec (Canada); Sarill, Miles [Department of Medicine, McGill University, Montreal, Quebec (Canada); Rico de Souza, Angela [Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec (Canada); Gomez, Alvin; Matthews, Jason [Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON (Canada); Hamid, Qutayba; Eidelman, David H. [Department of Medicine, McGill University, Montreal, Quebec (Canada); Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec (Canada); Baglole, Carolyn J., E-mail: Carolyn.baglole@McGill.ca [Department of Medicine, McGill University, Montreal, Quebec (Canada); Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec (Canada)

    2014-11-01

    The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor implicated in the regulation of apoptosis and proliferation. Although activation of the AhR by xenobiotics such as dioxin inhibits the cell cycle and control apoptosis, paradoxically, AhR expression also promotes cell proliferation and survival independent of exogenous ligands. The microRNA (miRNA) miR-196a has also emerged as a regulator of proliferation and apoptosis but a relationship between the AhR and miR-196a is not known. Therefore, we hypothesized that AhR-dependent regulation of endogenous miR-196a expression would promote cell survival and proliferation. Utilizing lung fibroblasts from AhR deficient (AhR{sup −/−}) and wild-type (AhR{sup +/+}) mice, we show that there is ligand-independent regulation of miRNA, including low miR-196a in AhR{sup −/−} cells. Validation by qRT-PCR revealed a significant decrease in basal expression of miR-196a in AhR{sup −/−} compared to AhR{sup +/+} cells. Exposure to AhR agonists benzo[a]pyrene (B[a]P) and FICZ as well as AhR antagonist CH-223191 decreased miR-196a expression in AhR{sup +/+} fibroblasts concomitant with decreased AhR protein levels. There was increased proliferation only in AhR{sup +/+} lung fibroblasts in response to serum, corresponding to a decrease in p27{sup KIP1} protein, a cyclin-dependent kinase inhibitor. Increasing the cellular levels of miR-196a had no effect on proliferation or expression of p27{sup KIP1} in AhR{sup −/−} fibroblasts but attenuated cigarette smoke-induced apoptosis. This study provides the first evidence that AhR expression is essential for the physiological regulation of cellular miRNA levels- including miR-196a. Future experiments designed to elucidate the functional relationship between the AhR and miR-196a may delineate additional novel ligand-independent roles for the AhR. - Highlights: • The AhR controls proliferation and apoptosis in lung cells. • The AhR regulates the

  2. PI3-kinase γ promotes Rap1a-mediated activation of myeloid cell integrin α4β1, leading to tumor inflammation and growth.

    Directory of Open Access Journals (Sweden)

    Michael C Schmid

    Full Text Available Tumor inflammation, the recruitment of myeloid lineage cells into the tumor microenvironment, promotes angiogenesis, immunosuppression and metastasis. CD11b+Gr1lo monocytic lineage cells and CD11b+Gr1hi granulocytic lineage cells are recruited from the circulation by tumor-derived chemoattractants, which stimulate PI3-kinase γ (PI3Kγ-mediated integrin α4 activation and extravasation. We show here that PI3Kγ activates PLCγ, leading to RasGrp/CalDAG-GEF-I&II mediated, Rap1a-dependent activation of integrin α4β1, extravasation of monocytes and granulocytes, and inflammation-associated tumor progression. Genetic depletion of PLCγ, CalDAG-GEFI or II, Rap1a, or the Rap1 effector RIAM was sufficient to prevent integrin α4 activation by chemoattractants or activated PI3Kγ (p110γCAAX, while activated Rap (RapV12 promoted constitutive integrin activation and cell adhesion that could only be blocked by inhibition of RIAM or integrin α4β1. Similar to blockade of PI3Kγ or integrin α4β1, blockade of Rap1a suppressed both the recruitment of monocytes and granulocytes to tumors and tumor progression. These results demonstrate critical roles for a PI3Kγ-Rap1a-dependent pathway in integrin activation during tumor inflammation and suggest novel avenues for cancer therapy.

  3. Role of Interaction and Nucleoside Diphosphate Kinase B in Regulation of the Cystic Fibrosis Transmembrane Conductance Regulator Function by cAMP-Dependent Protein Kinase A.

    Directory of Open Access Journals (Sweden)

    Lee A Borthwick

    Full Text Available Cystic fibrosis results from mutations in the cystic fibrosis transmembrane conductance regulator (CFTR, a cAMP-dependent protein kinase A (PKA and ATP-regulated chloride channel. Here, we demonstrate that nucleoside diphosphate kinase B (NDPK-B, NM23-H2 forms a functional complex with CFTR. In airway epithelia forskolin/IBMX significantly increases NDPK-B co-localisation with CFTR whereas PKA inhibitors attenuate complex formation. Furthermore, an NDPK-B derived peptide (but not its NDPK-A equivalent disrupts the NDPK-B/CFTR complex in vitro (19-mers comprising amino acids 36-54 from NDPK-B or NDPK-A. Overlay (Far-Western and Surface Plasmon Resonance (SPR analysis both demonstrate that NDPK-B binds CFTR within its first nucleotide binding domain (NBD1, CFTR amino acids 351-727. Analysis of chloride currents reflective of CFTR or outwardly rectifying chloride channels (ORCC, DIDS-sensitive showed that the 19-mer NDPK-B peptide (but not its NDPK-A equivalent reduced both chloride conductances. Additionally, the NDPK-B (but not NDPK-A peptide also attenuated acetylcholine-induced intestinal short circuit currents. In silico analysis of the NBD1/NDPK-B complex reveals an extended interaction surface between the two proteins. This binding zone is also target of the 19-mer NDPK-B peptide, thus confirming its capability to disrupt NDPK-B/CFTR complex. We propose that NDPK-B forms part of the complex that controls chloride currents in epithelia.

  4. Lanthanide-Dependent Regulation of Methanol Oxidation Systems in Methylobacterium extorquens AM1 and Their Contribution to Methanol Growth.

    Science.gov (United States)

    Vu, Huong N; Subuyuj, Gabriel A; Vijayakumar, Srividhya; Good, Nathan M; Martinez-Gomez, N Cecilia; Skovran, Elizabeth

    2016-04-01

    , our data suggest that M. extorquens AM1 has a mechanism to regulate which MeDH is transcribed, depending on the presence or absence of lanthanides. While the mechanism controlling differential regulation is not yet understood, further research into how methylotrophs obtain and use lanthanides will facilitate their cultivation in the laboratory and their use as a biomining and biorecycling strategy for recovery of these commercially valuable rare-earth elements. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  5. Up-regulation of ROS by mitochondria-dependent bystander signaling contributes to genotoxicity of bystander effects

    International Nuclear Information System (INIS)

    Chen Shaopeng; Zhao Ye; Zhao Guoping; Han Wei; Bao Lingzhi; Yu, K.N.; Wu Lijun

    2009-01-01

    Genomic instability can be observed in bystander cells. However, the underlying mechanism(s) is still relatively unclear. In a previous study, we found that irradiated cells released mitochondria-dependent intracellular factor(s) which could lead to bystander γ-H2AX induction. In this paper, we used normal (ρ + ) and mtDNA-depleted (ρ 0 ) human-hamster hybrid cells to investigate mitochondrial effects on the genotoxicity in bystander effect through medium transfer experiments. Through the detection of DNA double-strand breaks with γ-H2AX, we found that the fraction of γ-H2AX positive cells changed with time when irradiation conditioned cell medium (ICCM) were harvested. ICCM harvested from irradiated ρ + cells at 10 min post-irradiation (ρ + ICCM 10min ) caused larger increases of bystander γ-H2AX induction comparing to ρ 0 ICCM 10min , which only caused a slight increase of bystander γ-H2AX induction. The ρ + ICCM 10min could also result in the up-regulation of ROS production (increased by 35% at 10 min), while there was no significant increase in cells treated with ρ 0 ICCM 10min . We treated cells with dimethyl sulfoxide (DMSO), the scavenger of ROS, and quenched γ-H2AX induction by ρ + ICCM. Furthermore, after the medium had been transferred and the cells were continuously cultured for 7 days, we found significantly increased CD59 - gene loci mutation (increased by 45.9%) and delayed cell death in the progeny of ρ + ICCM-treated bystander cells. In conclusion, the work presented here suggested that up-regulation of the mitochondria-dependent ROS might be very important in mediating genotoxicity of bystander effects.

  6. Neuronal extracellular signal-regulated kinase (ERK activity as marker and mediator of alcohol and opioid dependence

    Directory of Open Access Journals (Sweden)

    Eva R. Zamora-Martinez

    2014-03-01

    Full Text Available Early pioneering work in the field of biochemistry identified phosphorylation as a crucial post-translational modification of proteins with the ability to both indicate and arbitrate complex physiological processes. More recent investigations have functionally linked phosphorylation of extracellular signal-regulated kinase (ERK to a variety of neurophysiological mechanisms ranging from acute neurotransmitter action to long-term gene expression. ERK phosphorylation serves as an intracellular bridging mechanism that facilitates neuronal communication and plasticity. Drugs of abuse, including alcohol and opioids, act as artificial yet powerful rewards that impinge upon natural reinforcement processes critical for survival. The graded progression from initial exposure to addiction (or substance dependence is believed to result from drug- and drug context-induced adaptations in neuronal signaling processes across brain reward and stress circuits following excessive drug use. In this regard, commonly abused drugs as well as drug-associated experiences are capable of modifying the phosphorylation of ERK within central reinforcement systems. In addition, chronic drug and alcohol exposure may drive ERK-regulated epigenetic and structural alterations that underlie a long-term propensity for escalating drug use. Under the influence of such a neurobiological vulnerability, encountering drug-associated cues and contexts can produce subsequent alterations in ERK signaling that drive relapse to drug and alcohol seeking. Current studies are determining precisely which molecular and regional ERK phosphorylation-associated events contribute to the addiction process, as well as which neuroadaptations need to be targeted in order to return dependent individuals to a healthy state.

  7. Up-regulation of ROS by mitochondria-dependent bystander signaling contributes to genotoxicity of bystander effects

    Energy Technology Data Exchange (ETDEWEB)

    Chen Shaopeng [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Zhao Ye; Zhao Guoping [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Han Wei [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Bao Lingzhi [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Yu, K.N., E-mail: peter.yu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Wu Lijun, E-mail: ljw@ipp.ac.cn [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2009-06-18

    Genomic instability can be observed in bystander cells. However, the underlying mechanism(s) is still relatively unclear. In a previous study, we found that irradiated cells released mitochondria-dependent intracellular factor(s) which could lead to bystander {gamma}-H2AX induction. In this paper, we used normal ({rho}{sup +}) and mtDNA-depleted ({rho}{sup 0}) human-hamster hybrid cells to investigate mitochondrial effects on the genotoxicity in bystander effect through medium transfer experiments. Through the detection of DNA double-strand breaks with {gamma}-H2AX, we found that the fraction of {gamma}-H2AX positive cells changed with time when irradiation conditioned cell medium (ICCM) were harvested. ICCM harvested from irradiated {rho}{sup +} cells at 10 min post-irradiation ({rho}{sup +} ICCM{sub 10min}) caused larger increases of bystander {gamma}-H2AX induction comparing to {rho}{sup 0} ICCM{sub 10min}, which only caused a slight increase of bystander {gamma}-H2AX induction. The {rho}{sup +} ICCM{sub 10min} could also result in the up-regulation of ROS production (increased by 35% at 10 min), while there was no significant increase in cells treated with {rho}{sup 0} ICCM{sub 10min}. We treated cells with dimethyl sulfoxide (DMSO), the scavenger of ROS, and quenched {gamma}-H2AX induction by {rho}{sup +} ICCM. Furthermore, after the medium had been transferred and the cells were continuously cultured for 7 days, we found significantly increased CD59{sup -} gene loci mutation (increased by 45.9%) and delayed cell death in the progeny of {rho}{sup +} ICCM-treated bystander cells. In conclusion, the work presented here suggested that up-regulation of the mitochondria-dependent ROS might be very important in mediating genotoxicity of bystander effects.

  8. The multi-targeted kinase inhibitor sorafenib inhibits enterovirus 71 replication by regulating IRES-dependent translation of viral proteins.

    Science.gov (United States)

    Gao, Meng; Duan, Hao; Liu, Jing; Zhang, Hao; Wang, Xin; Zhu, Meng; Guo, Jitao; Zhao, Zhenlong; Meng, Lirong; Peng, Yihong

    2014-06-01

    The activation of ERK and p38 signal cascade in host cells has been demonstrated to be essential for picornavirus enterovirus 71 (EV71) replication and up-regulation of virus-induced cyclooxygenase-2 (COX-2)/prostaglandins E2 (PGE2) expression. The aim of this study was to examine the effects of sorafenib, a clinically approved anti-cancer multi-targeted kinase inhibitor, on the propagation and pathogenesis of EV71, with a view to its possible mechanism and potential use in the design of therapy regimes for Hand foot and mouth disease (HFMD) patients with life threatening neurological complications. In this study, non-toxic concentrations of sorafenib were shown to inhibit the yield of infectious progeny EV71 (clinical BC08 strain) by about 90% in three different cell types. A similar inhibitory effect of sorafenib was observed on the synthesis of both viral genomic RNA and the VP1 protein. Interestingly, sorafenib exerted obvious inhibition of the EV71 internal ribosomal entry site (IRES)-mediated translation, the first step in picornavirus replication, by linking it to a firefly luciferase reporter gene. Sorafenib was also able to prevent both EV71-induced CPE and the activation of ERK and p38, which contributes to up-regulation COX-2/PGE2 expression induced by the virus. Overall, this study shows that sorafenib strongly inhibits EV71 replication at least in part by regulating viral IRES-dependent translation of viral proteins, indicating a novel potential strategy for the treatment of HFMD patients with severe neurological complications. To our knowledge, this is the first report that investigates the mechanism by which sorafenib inhibits EV71 replication. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Letrozole regulates actin cytoskeleton polymerization dynamics in a SRC-1 dependent manner in the hippocampus of mice.

    Science.gov (United States)

    Zhao, Yangang; Yu, Yanlan; Zhang, Yuanyuan; He, Li; Qiu, Linli; Zhao, Jikai; Liu, Mengying; Zhang, Jiqiang

    2017-03-01

    In the hippocampus, local estrogens (E 2 ) derived from testosterone that is catalyzed by aromatase play important roles in the regulation of hippocampal neural plasticity, but the underlying mechanisms remain unclear. The actin cytoskeleton contributes greatly to hippocampal synaptic plasticity; however, whether it is regulated by local E 2 and the related mechanisms remain to be elucidated. In this study, we first examined the postnatal developmental profiles of hippocampal aromatase and specific proteins responsible for actin cytoskeleton dynamics. Then we used aromatase inhibitor letrozole (LET) to block local E 2 synthesis and examined the changes of these proteins and steroid receptor coactivator-1 (SRC-1), the predominant coactivator for steroid nuclear receptors. Finally, SRC-1 specific RNA interference was used to examine the effects of SRC-1 on the expression of these actin remodeling proteins. The results showed a V-type profile for aromatase and increased profiles for actin cytoskeleton proteins in both male and female hippocampus without obvious sex differences. LET treatment dramatically decreased the F-actin/G-actin ratio, the expression of Rictor, phospho-AKT (ser473), Profilin-1, phospho-Cofilin (Ser3), and SRC-1 in a dose-dependent manner. In vitro studies demonstrated that LET induced downregulation of these proteins could be reversed by E 2 , and E 2 induced increase of these proteins were significantly suppressed by SRC-1 shRNA interference. These results for the first time clearly demonstrated that local E 2 inhibition could induce aberrant actin polymerization; they also showed an important role of SRC-1 in the mediation of local E 2 action on hippocampal synaptic plasticity by regulation of actin cytoskeleton dynamics. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Regulation of flow through a T-Shaped open cavity by temperature dependent P, PI, and PID controllers

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Sourav, E-mail: ssaha09@me.buet.ac.bd; Mojumder, Satyajit, E-mail: satyajit@me.buet.ac.bd; Saha, Sumon, E-mail: sumonsaha@me.buet.ac.bd [Department of Mechanical Engineering, Bangladesh University of Engineering and Technology, Dhaka-1000 (Bangladesh)

    2016-07-12

    P (proportional), PI (proportional-integral), and PID (proportional-integral-derivative) controllers are popular means of controlling industrial processes. Due to superior response, accuracy, and stable performance, PID controllers are mostly used in control systems. This paper presents a mathematical model and subsequent response analysis regarding regulation of flow in mixed convection through a T-shaped open cavity by temperature dependent controllers. The T-shaped cavity has cold top and hot bottom walls, while air is flowing through the inlet at surrounding temperature. The inflow is regulated by a controlled gate which operates according to the signal received from the controller. Values of proportional gain (k{sub p}), integral gain (k{sub i}), and derivative gain (k{sub d}) are varied to obtain the desired system response and to ensure a stable system with fastest response. At first, only P controller is used and eventually PI and finally PID control scheme is applied for controller tuning. Tuning of different controllers (P, PI, and PID) are carried out systematically based on the reference temperature which is continuously monitored at a certain location inside the cavity. It is found that PID controller performs better than P or PI controller.

  11. Mg(2+,ATP-dependent plasma membrane calcium pump of smooth muscle cells. ІІ. Regulation of activity

    Directory of Open Access Journals (Sweden)

    T. О. Veklich

    2015-04-01

    Full Text Available Plasma membrane Ca2+-pump is one of key proteins, which takes part in Ca2+ exchange in smooth muscle cells. It has a lot of diverse functions from control of basal cytoplasmal Ca2+ concentration to regulation of proteins involved in Ca2+-dependent signal pathway. Ca2+ pump function is often depen­dent on the isoform or even form of alternative splicing. Allowing for a variety of Ca2+-pump functions and properties, which were reviewed in detail in the first part of our review article cycle (Ukr. Biochem. J., 2015; 87(1, the precise control of the mentioned pump activity is very important for cell functioning­. The other part of this article is dedicated to different regulation factors of smooth muscle plasma membrane Ca2+-pump activity: endogenous and exo­genous, biotic and abiotic factors. Special attention is given to literature data and own results about design and the search of selective plasma membrane Ca2+-pump inhibitor which would allow examining its functioning in smooth muscle cells more meticulously.

  12. Regulation of flow through a T-Shaped open cavity by temperature dependent P, PI, and PID controllers

    International Nuclear Information System (INIS)

    Saha, Sourav; Mojumder, Satyajit; Saha, Sumon

    2016-01-01

    P (proportional), PI (proportional-integral), and PID (proportional-integral-derivative) controllers are popular means of controlling industrial processes. Due to superior response, accuracy, and stable performance, PID controllers are mostly used in control systems. This paper presents a mathematical model and subsequent response analysis regarding regulation of flow in mixed convection through a T-shaped open cavity by temperature dependent controllers. The T-shaped cavity has cold top and hot bottom walls, while air is flowing through the inlet at surrounding temperature. The inflow is regulated by a controlled gate which operates according to the signal received from the controller. Values of proportional gain (k p ), integral gain (k i ), and derivative gain (k d ) are varied to obtain the desired system response and to ensure a stable system with fastest response. At first, only P controller is used and eventually PI and finally PID control scheme is applied for controller tuning. Tuning of different controllers (P, PI, and PID) are carried out systematically based on the reference temperature which is continuously monitored at a certain location inside the cavity. It is found that PID controller performs better than P or PI controller.

  13. Phospholipid mediated activation of calcium dependent protein kinase 1 (CaCDPK1 from chickpea: a new paradigm of regulation.

    Directory of Open Access Journals (Sweden)

    Ajay Kumar Dixit

    Full Text Available Phospholipids, the major structural components of membranes, can also have functions in regulating signaling pathways in plants under biotic and abiotic stress. The effects of adding phospholipids on the activity of stress-induced calcium dependent protein kinase (CaCDPK1 from chickpea are reported here. Both autophosphorylation as well as phosphorylation of the added substrate were enhanced specifically by phosphatidylcholine and to a lesser extent by phosphatidic acid, but not by phosphatidylethanolamine. Diacylgylerol, the neutral lipid known to activate mammalian PKC, stimulated CaCDPK1 but at higher concentrations. Increase in V(max of the enzyme activity by these phospholipids significantly decreased the K(m indicating that phospholipids enhance the affinity towards its substrate. In the absence of calcium, addition of phospholipids had no effect on the negligible activity of the enzyme. Intrinsic fluorescence intensity of the CaCDPK1 protein was quenched on adding PA and PC. Higher binding affinity was found with PC (K(½ = 114 nM compared to PA (K(½ = 335 nM. We also found that the concentration of PA increased in chickpea plants under salt stress. The stimulation by PA and PC suggests regulation of CaCDPK1 by these phospholipids during stress response.

  14. Regulation of NKG2D-Dependent NK Cell Functions: The Yin and the Yang of Receptor Endocytosis

    Directory of Open Access Journals (Sweden)

    Rosa Molfetta

    2017-08-01

    Full Text Available Natural-killer receptor group 2, member D (NKG2D is a well characterized natural killer (NK cell activating receptor that recognizes several ligands poorly expressed on healthy cells but up-regulated upon stressing stimuli in the context of cancer or viral infection. Although NKG2D ligands represent danger signals that render target cells more susceptible to NK cell lysis, accumulating evidence demonstrates that persistent exposure to ligand-expressing cells causes the decrease of NKG2D surface expression leading to a functional impairment of NKG2D-dependent NK cell functions. Upon ligand binding, NKG2D is internalized from the plasma membrane and sorted to lysosomes for degradation. However, receptor endocytosis is not only a mechanism of receptor clearance from the cell surface, but is also required for the proper activation of signalling events leading to the functional program of NK cells. This review is aimed at providing a summary of current literature relevant to the molecular mechanisms leading to NKG2D down-modulation with particular emphasis given to the role of NKG2D endocytosis in both receptor degradation and signal propagation. Examples of chronic ligand-induced down-regulation of NK cell activating receptors other than NKG2D, including natural cytotoxicity receptors (NCRs, DNAX accessory molecule-1 (DNAM1 and CD16, will be also discussed.

  15. Lysosomal metabolomics reveals V-ATPase- and mTOR-dependent regulation of amino acid efflux from lysosomes.

    Science.gov (United States)

    Abu-Remaileh, Monther; Wyant, Gregory A; Kim, Choah; Laqtom, Nouf N; Abbasi, Maria; Chan, Sze Ham; Freinkman, Elizaveta; Sabatini, David M

    2017-11-10

    The lysosome degrades and recycles macromolecules, signals to the cytosol and nucleus, and is implicated in many diseases. Here, we describe a method for the rapid isolation of mammalian lysosomes and use it to quantitatively profile lysosomal metabolites under various cell states. Under nutrient-replete conditions, many lysosomal amino acids are in rapid exchange with those in the cytosol. Loss of lysosomal acidification through inhibition of the vacuolar H + -adenosine triphosphatase (V-ATPase) increased the luminal concentrations of most metabolites but had no effect on those of the majority of essential amino acids. Instead, nutrient starvation regulates the lysosomal concentrations of these amino acids, an effect we traced to regulation of the mechanistic target of rapamycin (mTOR) pathway. Inhibition of mTOR strongly reduced the lysosomal efflux of most essential amino acids, converting the lysosome into a cellular depot for them. These results reveal the dynamic nature of lysosomal metabolites and that V-ATPase- and mTOR-dependent mechanisms exist for controlling lysosomal amino acid efflux. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  16. Malaria parasite cGMP-dependent protein kinase regulates blood stage merozoite secretory organelle discharge and egress.

    Directory of Open Access Journals (Sweden)

    Christine R Collins

    2013-05-01

    Full Text Available The malaria parasite replicates within an intraerythrocytic parasitophorous vacuole (PV. Eventually, in a tightly regulated process called egress, proteins of the PV and intracellular merozoite surface are modified by an essential parasite serine protease called PfSUB1, whilst the enclosing PV and erythrocyte membranes rupture, releasing merozoites to invade fresh erythrocytes. Inhibition of the Plasmodium falciparum cGMP-dependent protein kinase (PfPKG prevents egress, but the underlying mechanism is unknown. Here we show that PfPKG activity is required for PfSUB1 discharge into the PV, as well as for release of distinct merozoite organelles called micronemes. Stimulation of PfPKG by inhibiting parasite phosphodiesterase activity induces premature PfSUB1 discharge and egress of developmentally immature, non-invasive parasites. Our findings identify the signalling pathway that regulates PfSUB1 function and egress, and raise the possibility of targeting PfPKG or parasite phosphodiesterases in therapeutic approaches to dysregulate critical protease-mediated steps in the parasite life cycle.

  17. Regulation of hippocampus-dependent memory by the zinc finger protein Zbtb20 in mature CA1 neurons.

    Science.gov (United States)

    Ren, Anjing; Zhang, Huan; Xie, Zhifang; Ma, Xianhua; Ji, Wenli; He, David Z Z; Yuan, Wenjun; Ding, Yu-Qiang; Zhang, Xiao-Hui; Zhang, Weiping J

    2012-10-01

    The mammalian hippocampus harbours neural circuitry that is crucial for associative learning and memory. The mechanisms that underlie the development and regulation of this complex circuitry are not fully understood. Our previous study established an essential role for the zinc finger protein Zbtb20 in the specification of CA1 field identity in the developing hippocampus. Here, we show that conditionally deleting Zbtb20 specifically in mature CA1 pyramidal neurons impaired hippocampus-dependent memory formation, without affecting hippocampal architecture or the survival, identity and basal excitatory synaptic activity of CA1 pyramidal neurons. We demonstrate that mature CA1-specific Zbtb20 knockout mice exhibited reductions in long-term potentiation (LTP) and NMDA receptor (NMDAR)-mediated excitatory post-synaptic currents. Furthermore, we show that activity-induced phosphorylation of ERK and CREB is impaired in the hippocampal CA1 of Zbtb20 mutant mice. Collectively, these results indicate that Zbtb20 in mature CA1 plays an important role in LTP and memory by regulating NMDAR activity, and activation of ERK and CREB.

  18. Hypoxia-Inducible Factor 3 Is an Oxygen-Dependent Transcription Activator and Regulates a Distinct Transcriptional Response to Hypoxia

    Directory of Open Access Journals (Sweden)

    Peng Zhang

    2014-03-01

    Full Text Available Hypoxia-inducible factors (HIFs play key roles in the cellular response to hypoxia. It is widely accepted that whereas HIF-1 and HIF-2 function as transcriptional activators, HIF-3 inhibits HIF-1/2α action. Contrary to this idea, we show that zebrafish Hif-3α has strong transactivation activity. Hif-3α is degraded under normoxia. Mutation of P393, P493, and L503 inhibits this oxygen-dependent degradation. Transcriptomics and chromatin immunoprecipitation analyses identify genes that are regulated by Hif-3α, Hif-1α, or both. Under hypoxia or when overexpressed, Hif-3α binds to its target gene promoters and upregulates their expression. Dominant-negative inhibition and knockdown of Hif-3α abolish hypoxia-induced Hif-3α-promoter binding and gene expression. Hif-3α not only mediates hypoxia-induced growth and developmental retardation but also possesses hypoxia-independent activities. Importantly, transactivation activity is conserved and human HIF-3α upregulates similar genes in human cells. These findings suggest that Hif-3 is an oxygen-dependent transcription factor and activates a distinct transcriptional response to hypoxia.

  19. Regulation of c–myc expression by IFN–γ through Stat1-dependent and -independent pathways

    Science.gov (United States)

    Ramana, Chilakamarti V.; Grammatikakis, Nicholas; Chernov, Mikhail; Nguyen, Hannah; Goh, Kee Chuan; Williams, Bryan R.G.; Stark, George R.

    2000-01-01

    Interferons (IFNs) inhibit cell growth in a Stat1-dependent fashion that involves regulation of c–myc expression. IFN–γ suppresses c–myc in wild-type mouse embryo fibroblasts, but not in Stat1-null cells, where IFNs induce c–myc mRNA rapidly and transiently, thus revealing a novel signaling pathway. Both tyrosine and serine phosphorylation of Stat1 are required for suppression. Induced expression of c–myc is likely to contribute to the proliferation of Stat1-null cells in response to IFNs. IFNs also suppress platelet-derived growth factor (PDGF)-induced c–myc expression in wild-type but not in Stat1-null cells. A gamma-activated sequence element in the promoter is necessary but not sufficient to suppress c–myc expression in wild-type cells. In PKR-null cells, the phosphorylation of Stat1 on Ser727 and transactivation are both defective, and c–myc mRNA is induced, not suppressed, in response to IFN–γ. A role for Raf–1 in the Stat1-independent pathway is revealed by studies with geldanamycin, an HSP90-specific inhibitor, and by expression of a mutant of p50cdc37 that is unable to recruit HSP90 to the Raf–1 complex. Both agents abrogated the IFN–γ-dependent induction of c–myc expression in Stat1-null cells. PMID:10637230

  20. System-dependent regulations of colour-pattern development: a mutagenesis study of the pale grass blue butterfly

    Science.gov (United States)

    Iwata, Masaki; Hiyama, Atsuki; Otaki, Joji M.

    2013-01-01

    Developmental studies on wing colour patterns have been performed in nymphalid butterflies, but efficient genetic manipulations, including mutagenesis, have not been well established. Here, we have performed mutagenesis experiments in a lycaenid butterfly, the pale grass blue Zizeeria maha, to produce colour-pattern mutants. We fed the P-generation larvae an artificial diet containing the mutagen ethyl methane sulfonate (EMS), and the F1- and F2-generation adults showed various aberrant colour patterns: dorsoventral transformation, anterioposterior background colouration gap, weak contrast, disarrangement of spots, reduction of the size of spots, loss of spots, fusion of spots, and ectopic spots. Among them, the disarrangement, reduction, and loss of spots were likely produced by the coordinated changes of many spots of a single wing around the discal spot in a system-dependent manner, demonstrating the existence of the central symmetry system. The present study revealed multiple genetic regulations for system-dependent and wing-wide colour-pattern determination in lycaenid butterflies. PMID:23917124

  1. Snf1 Phosphorylates Adenylate Cyclase and Negatively Regulates Protein Kinase A-dependent Transcription in Saccharomyces cerevisiae.

    Science.gov (United States)

    Nicastro, Raffaele; Tripodi, Farida; Gaggini, Marco; Castoldi, Andrea; Reghellin, Veronica; Nonnis, Simona; Tedeschi, Gabriella; Coccetti, Paola

    2015-10-09

    In eukaryotes, nutrient availability and metabolism are coordinated by sensing mechanisms and signaling pathways, which influence a broad set of cellular functions such as transcription and metabolic pathways to match environmental conditions. In yeast, PKA is activated in the presence of high glucose concentrations, favoring fast nutrient utilization, shutting down stress responses, and boosting growth. On the contrary, Snf1/AMPK is activated in the presence of low glucose or alternative carbon sources, thus promoting an energy saving program through transcriptional activation and phosphorylation of metabolic enzymes. The PKA and Snf1/AMPK pathways share common downstream targets. Moreover, PKA has been reported to negatively influence the activation of Snf1/AMPK. We report a new cross-talk mechanism with a Snf1-dependent regulation of the PKA pathway. We show that Snf1 and adenylate cyclase (Cyr1) interact in a nutrient-independent manner. Moreover, we identify Cyr1 as a Snf1 substrate and show that Snf1 activation state influences Cyr1 phosphorylation pattern, cAMP intracellular levels, and PKA-dependent transcription. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  2. Exoproteome Analysis of the Seaweed Pathogen Nautella italica R11 Reveals Temperature-Dependent Regulation of RTX-Like Proteins

    Directory of Open Access Journals (Sweden)

    Melissa Gardiner

    2017-06-01

    Full Text Available Climate fluctuations have been linked to an increased prevalence of disease in seaweeds, including the red alga Delisea pulchra, which is susceptible to a bleaching disease caused by the bacterium Nautella italica R11 under elevated seawater temperatures. To further investigate the role of temperature in the induction of disease by N. italica R11, we assessed the effect of temperature on the expression of the extracellular proteome (exoproteome in this bacterium. Label-free quantitative mass spectrometry was used to identify 207 proteins secreted into supernatant fraction, which is equivalent to 5% of the protein coding genes in the N. italica R11 genome. Comparative analysis demonstrated that expression of over 30% of the N. italica R11 exoproteome is affected by temperature. The temperature-dependent proteins include traits that could facilitate the ATP-dependent transport of amino acid and carbohydrate, as well as several uncharacterized proteins. Further, potential virulence determinants, including two RTX-like proteins, exhibited significantly higher expression in the exoproteome at the disease inducing temperature of 24°C relative to non-inducing temperature (16°C. This is the first study to demonstrate that temperature has an influence exoproteome expression in a macroalgal pathogen. The results have revealed several temperature regulated candidate virulence factors that may have a role in macroalgal colonization and invasion at elevated sea-surface temperatures, including novel RTX-like proteins.

  3. Twitchin can regulate the ATPase cycle of actomyosin in a phosphorylation-dependent manner in skinned mammalian skeletal muscle fibres.

    Science.gov (United States)

    Avrova, Stanislava V; Rysev, Nikita A; Matusovsky, Oleg S; Shelud'ko, Nikolay S; Borovikov, Yurii S

    2012-05-01

    The effect of twitchin, a thick filament protein of molluscan muscles, on the actin-myosin interaction at several mimicked sequential steps of the ATPase cycle was investigated using the polarized fluorescence of 1.5-IAEDANS bound to myosin heads, FITC-phalloidin attached to actin and acrylodan bound to twitchin in the glycerol-skinned skeletal muscle fibres of mammalian. The phosphorylation-dependent multi-step changes in mobility and spatial arrangement of myosin SH1 helix, actin subunit and twitchin during the ATPase cycle have been revealed. It was shown that nonphosphorylated twitchin inhibited the movements of SH1 helix of the myosin heads and actin subunits and decreased the affinity of myosin to actin by freezing the position and mobility of twitchin in the muscle fibres. The phosphorylation of twitchin reverses this effect by changing the spatial arrangement and mobility of the actin-binding portions of twitchin. In this case, enhanced movements of SH1 helix of the myosin heads and actin subunits are observed. The data imply a novel property of twitchin incorporated into organized contractile system: its ability to regulate the ATPase cycle in a phosphorylation-dependent fashion by changing the affinity and spatial arrangement of the actin-binding portions of twitchin. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. Double-stranded RNA promotes CTL-independent tumor cytolysis mediated by CD11b+Ly6G+ intratumor myeloid cells through the TICAM-1 signaling pathway

    Science.gov (United States)

    Shime, Hiroaki; Matsumoto, Misako; Seya, Tsukasa

    2017-01-01

    PolyI:C, a synthetic double-stranded RNA analog, acts as an immune-enhancing adjuvant that regresses tumors in cytotoxic T lymphocyte (CTL)-dependent and CTL-independent manner, the latter of which remains largely unknown. Tumors contain CD11b+Ly6G+ cells, known as granulocytic myeloid-derived suppressor cells (G-MDSCs) or tumor-associated neutrophils (TANs) that play a critical role in tumor progression and development. Here, we demonstrate that CD11b+Ly6G+ cells respond to polyI:C and exhibit tumoricidal activity in an EL4 tumor implant model. PolyI:C-induced inhibition of tumor growth was attributed to caspase-8/3 cascade activation in tumor cells that occurred independently of CD8α+/CD103+ dendritic cells (DCs) and CTLs. CD11b+Ly6G+ cells was essential for the antitumor effect because depletion of CD11b+Ly6G+ cells totally abrogated tumor regression and caspase activation after polyI:C treatment. CD11b+Ly6G+ cells that had been activated with polyI:C showed cytotoxicity and inhibited tumor growth through the production of reactive oxygen species (ROS)/reactive nitrogen species (RNS). These responses were abolished in either Toll/interleukin-1 receptor domain-containing adaptor molecule-1 (TICAM-1)−/− or interferon (IFN)-αβ receptor 1 (IFNAR1)−/− mice. Thus, our results suggest that polyI:C activates the TLR3/TICAM-1 and IFNAR signaling pathways in CD11b+Ly6G+ cells in tumors, thereby eliciting their antitumor activity, independent of those in CD8α+/CD103+ DCs that prime CTLs. PMID:27834952

  5. Nucleoporin 62 and Ca(2+)/calmodulin dependent kinase kinase 2 regulate androgen receptor activity in castrate resistant prostate cancer cells.

    Science.gov (United States)

    Karacosta, Loukia G; Kuroski, Laura A; Hofmann, Wilma A; Azabdaftari, Gissou; Mastri, Michalis; Gocher, Angela M; Dai, Shuhang; Hoste, Allen J; Edelman, Arthur M

    2016-02-15

    Re-activation of the transcriptional activity of the androgen receptor (AR) is an important factor mediating progression from androgen-responsive to castrate-resistant prostate cancer (CRPC). However, the mechanisms regulating AR activity in CRPC remain incompletely understood. Ca(2+) /calmodulin-dependent kinase kinase (CaMKK) 2 was previously shown to regulate AR activity in androgen-responsive prostate cancer cells. Our objective was to further explore the basis of this regulation in CRPC cells. The abundance of CaMKK2 in nuclear fractions of androgen-responsive prostate cancer and CRPC, cells were determined by subcellular fractionation and Western blotting. CaMKK2 association with nuclear pore complexes (NPCs) and nucleoporins (Nups) including Nup62, were imaged by structured illumination and super-resolution fluorescence microscopy and co-immunoprecipitation, respectively. The abundance and subcellular localization of CaMKK2 and Nup62 in human clinical specimens of prostate cancer was visualized by immunohistochemistry. The role of Nups in the growth and viability of CRPC cells was assessed by RNA interference and cell counting. The involvement of CaMKK2 and Nup62 in regulating AR transcriptional activity was addressed by RNA interference, chromatin immunoprecipitation, androgen response element reporter assay, and Western blotting. CaMKK2 was expressed at higher levels in the nuclear fraction of CPRC C4-2 cells, than in that of androgen-responsive LNCaP cells. In C4-2 cells, CaMKK2 associated with NPCs of the nuclear envelope and physically interacted with Nup62. CaMKK2 and Nup62 demonstrated pronounced, and similar increases in both expression and perinuclear/nuclear localization in human clinical specimens of advanced prostate cancer relative to normal prostate. Knockdown of Nup62, but not of Nups, 98 or 88, reduced growth and viability of C4-2 cells. Knockdown of Nup62 produced a greater reduction of the growth and viability of C4-2 cells than of non

  6. Oxidant-NO dependent gene regulation in dogs with type I diabetes: impact on cardiac function and metabolism

    Directory of Open Access Journals (Sweden)

    Ojaimi Caroline

    2010-08-01

    Full Text Available Abstract Background The mechanisms responsible for the cardiovascular mortality in type I diabetes (DM have not been defined completely. We have shown in conscious dogs with DM that: 1 baseline coronary blood flow (CBF was significantly decreased, 2 endothelium-dependent (ACh coronary vasodilation was impaired, and 3 reflex cholinergic NO-dependent coronary vasodilation was selectively depressed. The most likely mechanism responsible for the depressed reflex cholinergic NO-dependent coronary vasodilation was the decreased bioactivity of NO from the vascular endothelium. The goal of this study was to investigate changes in cardiac gene expression in a canine model of alloxan-induced type 1 diabetes. Methods Mongrel dogs were chronically instrumented and the dogs were divided into two groups: one normal and the other diabetic. In the diabetic group, the dogs were injected with alloxan monohydrate (40-60 mg/kg iv over 1 min. The global changes in cardiac gene expression in dogs with alloxan-induced diabetes were studied using Affymetrix Canine Array. Cardiac RNA was extracted from the control and DM (n = 4. Results The array data revealed that 797 genes were differentially expressed (P 2+ cycling genes (ryanodine receptor; SERCA2 Calcium ATPase, structural proteins (actin alpha. Of particular interests are genes involved in glutathione metabolism (glutathione peroxidase 1, glutathione reductase and glutathione S-transferase, which were markedly down regulated. Conclusion our findings suggest that type I diabetes might have a direct effect on the heart by impairing NO bioavailability through oxidative stress and perhaps lipid peroxidases.

  7. TPL-2 Regulates Macrophage Lipid Metabolism and M2 Differentiation to Control TH2-Mediated Immunopathology

    Science.gov (United States)

    Entwistle, Lewis J.; Khoury, Hania; Papoutsopoulou, Stamatia; Mahmood, Radma; Mansour, Nuha R.; Ching-Cheng Huang, Stanley; Pearce, Edward J.; Pedro S. de Carvalho, Luiz; Ley, Steven C.

    2016-01-01

    Persistent TH2 cytokine responses following chronic helminth infections can often lead to the development of tissue pathology and fibrotic scarring. Despite a good understanding of the cellular mechanisms involved in fibrogenesis, there are very few therapeutic options available, highlighting a significant medical need and gap in our understanding of the molecular mechanisms of TH2-mediated immunopathology. In this study, we found that the Map3 kinase, TPL-2 (Map3k8; Cot) regulated TH2-mediated intestinal, hepatic and pulmonary immunopathology following Schistosoma mansoni infection or S. mansoni egg injection. Elevated inflammation, TH2 cell responses and exacerbated fibrosis in Map3k8 –/–mice was observed in mice with myeloid cell-specific (LysM) deletion of Map3k8, but not CD4 cell-specific deletion of Map3k8, indicating that TPL-2 regulated myeloid cell function to limit TH2-mediated immunopathology. Transcriptional and metabolic assays of Map3k8 –/–M2 macrophages identified that TPL-2 was required for lipolysis, M2 macrophage activation and the expression of a variety of genes involved in immuno-regulatory and pro-fibrotic pathways. Taken together this study identified that TPL-2 regulated TH2-mediated inflammation by supporting lipolysis and M2 macrophage activation, preventing TH2 cell expansion and downstream immunopathology and fibrosis. PMID:27487182

  8. DREAM mediates cAMP-dependent, Ca2+-induced stimulation of GFAP gene expression and regulates cortical astrogliogenesis.

    Science.gov (United States)

    Cebolla, Beatriz; Fernández-Pérez, Antonio; Perea, Gertrudis; Araque, Alfonso; Vallejo, Mario

    2008-06-25

    In the developing mouse brain, once the generation of neurons is mostly completed during the prenatal period, precisely coordinated signals act on competent neural precursors to direct their differentiation into astrocytes, which occurs mostly after birth. Among these signals, those provided by neurotrophic cytokines and bone morphogenetic proteins appear to have a key role in triggering the neurogenic to gliogenic switch and in regulating astrocyte numbers. In addition, we have reported previously that the neurotrophic peptide pituitary adenylate cyclase-activating polypeptide (PACAP) is able to promote astrocyte differentiation of cortical precursors via activation of a cAMP-dependent pathway. Signals acting on progenitor cells of the developing cortex to generate astrocytes activate glial fibrillary acidic protein (GFAP) gene expression, but the transcriptional mechanisms that regulate this activation are unclear. Here, we identify the previously known transcriptional repressor downstream regulatory element antagonist modulator (DREAM) as an activator of GFAP gene expression. We found that DREAM occupies specific sites on the GFAP promoter before and after differentiation is initiated by exposure of cortical progenitor cells to PACAP. PACAP raises intracellular calcium concentration via a mechanism that requires cAMP, and DREAM-mediated transactivation of the GFAP gene requires the integrity of calcium-binding domains. Cortical progenitor cells from dream(-/-) mice fail to express GFAP in response to PACAP. Moreover, the neonatal cortex of dream(-/-) mice exhibits a reduced number of astrocytes and increased number of neurons. These results identify the PACAP-cAMP-Ca(2+)-DREAM cascade as a new pathway to activate GFAP gene expression during astrocyte differentiation.

  9. Regulation of SIRT 1 mediated NAD dependent deacetylation: A novel role for the multifunctional enzyme CD38

    International Nuclear Information System (INIS)

    Aksoy, Pinar; Escande, Carlos; White, Thomas A.; Thompson, Michael; Soares, Sandra; Benech, Juan Claudio; Chini, Eduardo N.

    2006-01-01

    The SIRT 1 enzyme is a NAD dependent deacetylase implicated in ageing, cell protection, and energy metabolism in mammalian cells. How the endogenous activity of SIRT 1 is modulated is not known. The enzyme CD38 is a multifunctional enzyme capable of synthesis of the second messenger, cADPR, NAADP, and ADPR. However, the major enzymatic activity of CD38 is the hydrolysis of NAD. Of particular interest is the fact that CD38 is present on the inner nuclear membrane. Here, we investigate the modulation of the SIRT 1 activity by CD38. We propose that by modulating availability of NAD to the SIRT1 enzyme, CD38 may regulate SIRT1 enzymatic activity. We observed that in CD38 knockout mice, tissue levels of NAD are significantly increased. We also observed that incubation of purified recombinant SIRT1 enzyme with CD38 or nuclear extracts of wild-type mice led to a significant inhibition of its activity. In contrast, incubation of SIRT1 with cellular extract from CD38 knockout mice was without effect. Furthermore, the endogenous activity of SIRT1 was several time higher in nuclear extracts from CD38 knockout mice when compared to wild-type nuclear extracts. Finally, the in vivo deacetylation of the SIRT1 substrate P53 is increased in CD38 knockout mice tissue. Our data support the novel concept that nuclear CD38 is a major regulator of cellular/nuclear NAD level, and SIRT1 activity. These findings have strong implications for understanding the basic mechanisms that modulate intracellular NAD levels, energy homeostasis, as well as ageing and cellular protection modulated by the SIRT enzymes

  10. Isoginkgetin inhibits tumor cell invasion by regulating phosphatidylinositol 3-kinase/Akt-dependent matrix metalloproteinase-9 expression.

    Science.gov (United States)

    Yoon, Sang-Oh; Shin, Sejeong; Lee, Ho-Jae; Chun, Hyo-Kon; Chung, An-Sik

    2006-11-01

    Matrix metalloproteinase (MMP)-9 plays a key role in tumor invasion. Inhibitors of MMP-9 were screened from Metasequoia glyptostroboides (Dawn redwood) and one potent inhibitor, isoginkgetin, a biflavonoid, was identified. Noncytotoxic levels of isoginkgetin decreased MMP-9 production profoundly, but up-regulated the level of tissue inhibitor of metalloproteinase (TIMP)-1, an inhibitor of MMP-9, in HT1080 human fibrosarcoma cells. The major mechanism of Ras-dependent MMP-9 production in HT1080 cells was phosphatidylinositol 3-kinase (PI3K)/Akt/nuclear factor-kappaB (NF-kappaB) activation. Expression of dominant-active H-Ras and p85 (a subunit of PI3K) increased MMP-9 activity, whereas dominant-negative forms of these molecules decreased the level of MMP-9. H-Ras did not increase MMP-9 in the presence of a PI3K inhibitor, LY294002, and a NF-kappaB inhibitor, SN50. Further studies showed that isoginkgetin regulated MMP-9 production via PI3K/Akt/NF-kappaB pathway, as evidenced by the findings that isoginkgetin inhibited activities of both Akt and NF-kappaB. PI3K/Akt is a well-known key pathway for cell invasion, and isoginkgetin inhibited HT1080 tumor cell invasion substantially. Isoginkgetin was also quite effective in inhibiting the activities of Akt and MMP-9 in MDA-MB-231 breast carcinomas and B16F10 melanoma. Moreover, isoginkgetin treatment resulted in marked decrease in invasion of these cells. In summary, PI3K/Akt is a major pathway for MMP-9 expression and isoginkgetin markedly decreased MMP-9 expression and invasion through inhibition of this pathway. This suggests that isoginkgetin could be a potential candidate as a therapeutic agent against tumor invasion.

  11. Listeria monocytogenes Induces a Virulence-Dependent microRNA Signature That Regulates the Immune Response in Galleria mellonella

    Directory of Open Access Journals (Sweden)

    Gopala K. Mannala

    2017-12-01

    Full Text Available microRNAs (miRNAs coordinate several physiological and pathological processes by regulating the fate of mRNAs. Studies conducted in vitro indicate a role of microRNAs in the control of host-microbe interactions. However, there is limited understanding of miRNA functions in in vivo models of bacterial infections. In this study, we systematically explored changes in miRNA expression levels of Galleria mellonella larvae (greater-wax moth, a model system that recapitulates the vertebrate innate immunity, following infection with L. monocytogenes. Using an insect-specific miRNA microarray with more than 2000 probes, we found differential expression of 90 miRNAs (39 upregulated and 51 downregulated in response to infection with L. monocytogenes. We validated the expression of a subset of miRNAs which have mammalian homologs of known or predicted function. In contrast, non-pathogenic L. innocua failed to induce these miRNAs, indicating a virulence-dependent miRNA deregulation. To predict miRNA targets using established algorithms, we generated a publically available G. mellonella transcriptome database. We identified miRNA targets involved in innate immunity, signal transduction and autophagy, including spätzle, MAP kinase, and optineurin, respectively, which exhibited a virulence-specific differential expression. Finally, in silico estimation of minimum free energy of miRNA-mRNA duplexes of validated microRNAs and target transcripts revealed a regulatory network of the host immune response to L. monocytogenes. In conclusion, this study provides evidence for a role of miRNAs in the regulation of the innate immune response following bacterial infection in a simple, rapid and scalable in vivo model that may predict host-microbe interactions in higher vertebrates.

  12. Actin cytoskeleton-dependent Rab GTPase-regulated angiotensin type I receptor lysosomal degradation studied by fluorescence lifetime imaging microscopy

    Science.gov (United States)

    Li, Hewang; Yu, Peiying; Sun, Yuansheng; Felder, Robin A.; Periasamy, Ammasi; Jose, Pedro A.

    2010-09-01

    The dynamic regulation of the cellular trafficking of human angiotensin (Ang) type 1 receptor (AT1R) is not well understood. Therefore, we investigated the cellular trafficking of AT1R-enhanced green fluorescent protein (EGFP) (AT1R-EGFP) heterologously expressed in HEK293 cells by determining the change in donor lifetime (AT1R-EGFP) in the presence or absence of acceptor(s) using fluorescence lifetime imaging-fluorescence resonance energy transfer (FRET) microscopy. The average lifetime of AT1R-EGFP in our donor-alone samples was ~2.33 ns. The basal state lifetime was shortened slightly in the presence of Rab5 (2.01+/-0.10 ns) or Rab7 (2.11+/-0.11 ns) labeled with Alexa 555, as the acceptor fluorophore. A 5-min Ang II treatment markedly shortened the lifetime of AT1R-EGFP in the presence of Rab5-Alexa 555 (1.78+/-0.31 ns) but was affected minimally in the presence of Rab7-Alexa 555 (2.09+/-0.37 ns). A 30-min Ang II treatment further decreased the AT1R-EGFP lifetime in the presence of both Rab5- and Rab7-Alexa 555. Latrunculin A but not nocodazole pretreatment blocked the ability of Ang II to shorten the AT1R-EGFP lifetime. The occurrence of FRET between AT1R-EGFP (donor) and LAMP1-Alexa 555 (acceptor) with Ang II stimulation was impaired by photobleaching the acceptor. These studies demonstrate that Ang II-induced AT1R lysosomal degradation through its association with LAMP1 is regulated by Rab5/7 via mechanisms that are dependent on intact actin cytoskeletons.

  13. Expression of a TGF-{beta} regulated cyclin-dependent kinase inhibitor in normal and immortalized airway epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Tierney, L.A.; Bloomfield, C.; Johnson, N.F. [and others

    1995-12-01

    Tumors arising from epithelial cells, including lung cancers are frequently resistant to factors that regulate growth and differentiation in normal in normal cells. Once such factor is transforming growth factor-{Beta} (TGF-{Beta}). Escape from the growth-inhibitory effects of TGF-{Beta} is thought to be a key step in the transformation of airway epithelial cells. most lung cancer cell lines require serum for growth. In contrast, normal human bronchial epithelial (NHBE) cells are exquisitely sensitive to growth-inhibitory and differentiating effects of TGF-{Beta}. The recent identification of a novel cyclin-dependent kinase inhibitor, p15{sup INK4B}, which is regulated by TGF-{Beta}, suggests a mechanism by which TGF-{Beta} mediates growth arrest in NHBE cells. The purpose of this study was two-fold: (1) to determine if p15{sup INK4B} is induced by TGF-{Beta} in NHBE cells or immortalized bronchial epithelial (R.1) cells and if that induction corresponds to a G1/S cell-cycle arrest; (2) to determine the temporal relationship between p15{sup INK4B} induction, cell-cycle arrest, and the phosphorylation state of the pRB because it is thought that p15{sup INK4B} acts indirectly by preventing phosphorylation of the RB gene product. In this study, expression of p15{sup INK4B} was examined in NHBE cells and R.1 cells at different time intervals following TGF-{Beta} treatment. The expression of this kinase inhibitor and its relationship to the cell and the pRb phosphorylation state were examined in cells that were both sensitive (NHBE) and resistant (R.1) to the effects of TGF-{Beta}. These results suggest that the cyclin-dependent kinase inhibitor, p15{sup INK4B}, is involved in airway epithelial cell differentiation and that loss or reduction of expression plays a role in the resistance of transformed or neoplastic cells to the growth-inhibitory effects of TGF-{Beta}.

  14. Regulation of Reentrainment Function Is Dependent on a Certain Minimal Number of Intact Functional ipRGCs in rd Mice

    Directory of Open Access Journals (Sweden)

    Jingxue Zhang

    2017-01-01

    Full Text Available Purpose. To investigate the effect of partial ablation of melanopsin-containing retinal ganglion cells (mcRGCs on nonimage-forming (NIF visual functions in rd mice lacking rods. Methods. The rd mice were intravitreally injected with different doses (100 ng/μl, 200 ng/μl, and 400 ng/μl of immunotoxin melanopsin-SAP. And then, the density of ipRGCs was examined. After establishing the animal models with different degrees of ipRGC damage, a wheel-running system was used to evaluate their reentrainment response. Results. Intravitreal injection of melanopsin-SAP led to partial ablation of ipRGCs in a dose-dependent manner. The survival rates of ipRGCs in the 100 ng/μl, 200 ng/μl, and 400 ng/μl groups were 74.14% ± 4.15%, 39.25% ± 2.29%, and 38.38% ± 3.74%, respectively. The wheel-running experiments showed that more severe ipRGC loss was associated with a longer time needed for reentrainment. When the light/dark cycle was delayed by 8 h, the rd mice in the PBS control group took 4.67 ± 0.79 days to complete the synchronization with the shifted cycle, while those in the 100 ng/μl and 200 ng/μl groups required 7.90 ± 0.55 days and 11.00 ± 0.79 days to complete the synchronization with the new light/dark cycle, respectively. Conclusion. Our study indicates that the regulation of some NIF visual functions is dependent on a certain minimal number of intact functional ipRGCs.

  15. Death Receptor-Induced Apoptosis Signalling Regulation by Ezrin Is Cell Type Dependent and Occurs in a DISC-Independent Manner in Colon Cancer Cells

    Science.gov (United States)

    Iessi, Elisabetta; Zischler, Luciana; Etringer, Aurélie; Bergeret, Marion; Morlé, Aymeric; Jacquemin, Guillaume; Morizot, Alexandre; Shirley, Sarah; Lalaoui, Najoua; Elifio-Esposito, Selene L.; Fais, Stefano; Garrido, Carmen; Solary, Eric; Micheau, Olivier

    2015-01-01

    Ezrin belongs to the ERM (ezrin-radixin-moesin) protein family and has been demonstrated to regulate early steps of Fas receptor signalling in lymphoid cells, but its contribution to TRAIL-induced cell death regulation in adherent cancer cells remains unknown. In this study we report that regulation of FasL and TRAIL-induced cell death by ezrin is cell type dependant. Ezrin is a positive regulator of apoptosis in T-lymphoma cell line Jurkat, but a negative regulator in colon cancer cells. Using ezrin phosphorylation or actin-binding mutants, we provide evidence that negative regulation of death receptor-induced apoptosis by ezrin occurs in a cytoskeleton- and DISC-independent manner, in colon cancer cells. Remarkably, inhibition of apoptosis induced by these ligands was found to be tightly associated with regulation of ezrin phosphorylation on serine 66, the tumor suppressor gene WWOX and activation of PKA. Deficiency in WWOX expression in the liver cancer SK-HEP1 or the pancreatic Mia PaCa-2 cell lines as well as WWOX silencing or modulation of PKA activation by pharmacological regulators, in the colon cancer cell line SW480, abrogated regulation of TRAIL signalling by ezrin. Altogether our results show that death receptor pro-apoptotic signalling regulation by ezrin can occur downstream of the DISC in colon cancer cells. PMID:26010871

  16. Death Receptor-Induced Apoptosis Signalling Regulation by Ezrin Is Cell Type Dependent and Occurs in a DISC-Independent Manner in Colon Cancer Cells.

    Directory of Open Access Journals (Sweden)

    Elisabetta Iessi

    Full Text Available Ezrin belongs to the ERM (ezrin-radixin-moesin protein family and has been demonstrated to regulate early steps of Fas receptor signalling in lymphoid cells, but its contribution to TRAIL-induced cell death regulation in adherent cancer cells remains unknown. In this study we report that regulation of FasL and TRAIL-induced cell death by ezrin is cell type dependant. Ezrin is a positive regulator of apoptosis in T-lymphoma cell line Jurkat, but a negative regulator in colon cancer cells. Using ezrin phosphorylation or actin-binding mutants, we provide evidence that negative regulation of death receptor-induced apoptosis by ezrin occurs in a cytoskeleton- and DISC-independent manner, in colon cancer cells. Remarkably, inhibition of apoptosis induced by these ligands was found to be tightly associated with regulation of ezrin phosphorylation on serine 66, the tumor suppressor gene WWOX and activation of PKA. Deficiency in WWOX expression in the liver cancer SK-HEP1 or the pancreatic Mia PaCa-2 cell lines as well as WWOX silencing or modulation of PKA activation by pharmacological regulators, in the colon cancer cell line SW480, abrogated regulation of TRAIL signalling by ezrin. Altogether our results show that death receptor pro-apoptotic signalling regulation by ezrin can occur downstream of the DISC in colon cancer cells.

  17. Regulation

    International Nuclear Information System (INIS)

    Ballereau, P.

    1999-01-01

    The different regulations r