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Tiotropium bromide, a long acting muscarinic receptor antagonist triggers intracellular calcium signalling in the heart. Toxicol Appl Pharmacol 2019; 384:114778. [DOI: 10.1016/j.taap.2019.114778] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 09/14/2019] [Accepted: 10/06/2019] [Indexed: 12/30/2022]
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mRNA levels are buffered upon knockdown of RNA decay and translation factors via adjustment of transcription rates in human HepG2 cells. RNA Biol 2019; 16:1147-1155. [PMID: 31116665 DOI: 10.1080/15476286.2019.1621121] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Evidence from yeast and mammals argues the existence of cross-talk between transcription and mRNA decay. Stabilization of transcripts upon depletion of mRNA decay factors generally leads to no changes in mRNA abundance, attributing this to decreased transcription rates. We show that knockdown of human XRN1, CNOT6 and ETF1 genes in HepG2 cells led to significant alteration in stability of specific mRNAs, alterations in half-life were inversely associated with transcription rates, mostly not resulting in changes in abundance. We demonstrate the existence of the gene expression buffering mechanism in human cells that responds to both transcript stabilization and destabilization to maintain mRNA abundance via altered transcription rates and may involve translation. We propose that this buffering may hold novel cancer therapeutic targets.
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Differential Expression of Epidermal Growth Factor Receptor, Hepatocyte Growth Factor Receptor and Hypoxia‐Inducible Factor‐1‐Alpha in Aged Rat Livers. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.485.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Poster session 2Morphogenetic mechanisms290MiR-133 regulates retinoic acid pathway during early cardiac chamber specification291Bmp2 regulates atrial differentiation through miR-130 during early heart looping formationDevelopmental genetics294Association of deletion allele of insertion/deletion polymorphism in alpha 2B adrenoceptor gene and hypertension with or without type 2 diabetes mellitus295Association of G1359A polymorphism of the endocannabinoid type 1 receptor (CNR1) with coronary artery disease (CAD) with type 2 diabetes mellitusCell growth, differentiation and stem cells - Vascular298Gamma-secretase inhibitor prevents proliferation and migration of ductus arteriosus smooth muscle cells: a role of Notch signaling in postnatal closure of ductus arteriosus299Mesenchymal stromal-like cells (MLCs) derived from induced pluripotent stem (iPS) cells: a promising therapeutic option to promote neovascularization300Sonic Hedgehog promotes mesenchymal stem cell differentiation to vascular smooth muscle cells in cardiovacsular disease301Proinflammatory cytokine secretion and epigenetic modification in endothelial cells treated LPS-GinfivalisCell death and apoptosis - Vascular304Mitophagy acts as a safeguard mechanism against human vascular smooth muscle cell apoptosis induced by atherogenic lipidsTranscriptional control and RNA species - Vascular307MicroRNA-34a role in vascular calcification308Local delivery of a miR-146a inhibitor utilizing a clinically applicable approach attenuates neointima formation after vascular injury309Long noncoding RNA landscape of hypoxic endothelial cells310Specific circulating microRNAs levels associate with hypertension, hyperglycemia and dysfunctional HDL in acute coronary syndrome patientsCytokines and cellular inflammation - Vascular313Phosphodiesterase5A up-regulation in vascular endothelium under pro-inflammatory conditions: a newly disclosed anti-inflammatory activity for the omega-3polyunsaturated aatty acid docosahexaenoic acid314Cardiovascular risk modifying with extra-low dose anticytokine drugs in rhematoid arthritis315Conversion of human M-CSF macrophages into foam cells reduces their proinflammatory responses to classical M1-polarizing activation316Lymphocytic myocarditis coincides with increased plaque inflammation and plaque hemorrhage in coronary arteries, facilitating myocardial infarction317Serum osteoprotegerin level predictsdeclined numerous of circulating endothelial- derived and mononuclear-derived progenitor cells in patients with metabolic syndromeGrowth factors and neurohormones - Vascular320Effect of gastrin-releasing peptide (GRP) on vascular inflammationSignal transduction - Heart323A new synthetic peptide regulates hypertrophy in vitro through means of the inhibition of nfkb324Inducible fibroblast-specific knockout of p38 alpha map kinase is cardioprotective in a mouse model of isoproterenol-induced cardiac hypertrophy325Regulation of beta-adrenoceptor-evoked inotropic responses by inhibitory G protein, adenylyl cyclase isoforms 5 and 6 and phosphodiesterases326Binding to RGS3 and stimulation of M2 muscarinic acetylcholine receptors modulates the substrate specificity of p190RhoGAP in cardiac myocytes327Cardiac regulation of post-translational modifications, parylation and deacetylation in LMNA dilated cardiomyopathy mouse model328Beta-adrenergic regulation of the b56delta/pp2a holoenzyme in cardiac myocytes through b56delta phosphorylation at serine 573Nitric oxide and reactive oxygen species - Vascular331Oxidative stress-induced miR-200c disrupts the regulatory loop among SIRT1, FOXO1 and eNOS332Antioxidant therapy prevents oxidative stress-induced endothelial dysfunction and Enhances Wound Healing333Morphological and biochemical characterization of red blood cell in coronary artery diseaseCytoskeleton and mechanotransduction - Heart336Novel myosin activator, JSH compounds, increased myocardial contractility without chronotropic effect in ratsExtracellular matrix and fibrosis - Vascular339Ablation of Toll-like receptor 9 causes cardiac rupture after myocardial infarction by attenuating proliferation and differentiation of cardiac fibroblasts340Altered vascular remodeling in the mouse hind limb ischemia model in Factor VII activating protease (FSAP) deficiencyVasculogenesis, angiogenesis and arteriogenesis343Pro-angiogenic effects of proly-hydroxylase inhibitors and their potential for use in a novel strategy of therapeutic angiogenesis for coronary total occlusion344Nrf2 drives angiogenesis in transcription-independent manner: new function of the master regulator of oxidative stress response345Angiogenic gene therapy, despite efficient vascular growth, is not able to improve muscle function in normoxic or chronically ischemic rabbit hindlimbs -role of capillary arterialization and shunting346Effect of PAR-1 inhibition on collateral vessel growth in the murine hind limb model347Quaking is a key regulator of endothelial cell differentiation, neovascularization and angiogenesis348"Emerging angiogenesis" in the chick chorioallantoic membrane (CAM). An in vivo study349Exosomes from cardiomyocyte progenitor cells and mesenchymal stem cells stimulate angiogenesis in vitro and in vivo via EMMPRINEndothelium352Reciprocal regulation of GRK2 and bradykinin receptor stimulation modulate Ca2+ intracellular level in endothelial cells353The roles of bone morphogenetic proteins 9 and 10 in endothelial inflammation and atherosclerosis354The contribution of GPR55 to the L-alpha-lysophosphatidylinositol-induced vasorelaxation in isolated human pulmonary arteries355The endothelial protective ACE inhibitor Zofenoprilat exerts anti-inflammatory activities through H2S production356A new class of glycomimetic drugs to prevent free fatty acid-induced endothelial dysfunction357Endothelial progenitor cells to apoptotic endothelial cell-derived microparticles ration differentiatesas preserved from reduced ejection fractionheart failure358Proosteogenic genes are activated in endothelial cells of patients with thoracic aortic aneurysm359Endothelin ETB receptors mediate relaxing responses to insulin in pericardial resistance arteries from patients with cardiovascular disease (CVD)Smooth muscle and pericytes362CX3CR1 positive myeloid cells regulate vascular smooth muscle tone by inducing calcium oscillations via activation of IP3 receptors363A novel function of PI3Kg on cAMP regulation, role in arterial wall hyperplasia through modulation of smooth muscle cells proliferation364NRP1 and NRP2 play important roles in the development of neointimal hyperplasia in vivo365Azithromycin induces autophagy in aortic smooth muscle cellsCoagulation, thrombosis and platelets368The real time in vivo evaluation of platelet-dependent aldosterone prothrombotic action in mice369Development of a method for in vivo detection of active thrombi in mice370The antiplatelet effects of structural analogs of the taurine chloramine371The influence of heparin anticoagulant drugs on functional state of human platelets372Regulation of platelet aggregation and adenosine diphosphate release by d dimer in acute coronary syndrome (in vitro study)Oxygen sensing, ischaemia and reperfusion375Sirtuin 5 mediates brain injury in a mouse model of cerebral ischemia-reperfusion376Abscisic acid: a new player in cardiomyocyte protection from ischaemia?377Protective effects of ultramicronized palmitoylethanolamide (PEA-um) in myocardial ischaemia and reperfusion injury in vivo378Identification of stem cell-derived cardiomyocytes using cardiac specific markers and additional testing of these cells in simulated ischemia/reperfusion system379Single-dose intravenous metformin treatment could afford significant protection of the injured rat kidney in an experimental model of ischemia-reperfusion380Cardiotoxicity of long acting muscarinic receptor antagonists used for chronic obstructive pulmonary disease381Dependence antioxidant potential on the concentration of amino acids382The impact of ischemia-reperfusion on physiological parameters,apoptosis and ultrastructure of rabbit myocardium with experimental aterosclerosisMitochondria and energetics385MicroRNA-1 dependent regulation of mitochondrial calcium uniporter (MCU) in normal and hypertrophied hearts386Mitochondrial homeostasis and cardioprotection: common targets for desmin and aB-crystallin387Overexpression of mitofusin-2 (Mfn2) and associated mitochondrial dysfunction in the diabetic heart388NO-dependent prevention of permeability transition pore (MPTP) opening by H2S and its regulation of Ca2+ accumulation in rat heart mitochondria389G protein coupled receptor kinase 2 (GRK2) is fundamental in recovering mitochondrial morphology and function after exposure to ionizing radiation (IR)Gender issues392Sex differences in pulmonary vascular control; focus on the nitric oxide pathwayAging395Heart failure with preserved ejection fraction develops when feeding western diet to senescence-accelerated mice396Cardiovascular markers as predictors of cognitive decline in elderly hypertensive patients397Changes in connexin43 in old rats with volume overload chronic heart failureGenetics and epigenetics400Calcium content in the aortic valve is associated with 1G>2G matrix metalloproteinase 1 polymorphism401Neuropeptide receptor gene s (NPSR1) polymorphism and sleep disturbances402Endothelin-1 gene Lys198Asn polymorphism in men with essential hypertension complicated and uncomplicated with chronic heart failure403Association of common polymorphisms of the lipoprotein lipase and pon1 genes with the metabolic syndrome in a sample of community participantsGenomics, proteomics, metabolomics, lipidomics and glycomics405Gene expression quantification using multiplexed color-coded probe pairs to determine RNA content in sporadic cardiac myxoma406Large-scale phosphorylation study of the type 2 diabetic heart subjected to ischemia / reperfusion injury407Transcriptome-based identification of new anti-inflammatory properties of the olive oil hydroxytyrosol in vascular endothelial cell under basal and proinflammatory conditions408Gene polymorphisms combinations and risk of myocardial infarctionComputer modelling, bioinformatics and big data411Comparison of the repolarization reserve in three state-of-the-art models of the human ventricular action potentialMetabolism, diabetes mellitus and obesity414Endothelial monocyte-activating polypeptide-II improves heart function in type -I Diabetes mellitus415Admission glucose level is independent predictor of impaired left ventricular function in patients with acute myocardial infarction: a two dimensional speckle-tracking echocardiography study416Association between biochemical markers of lipid profile and inflammatory reaction and stiffness of the vascular wall in hypertensive patients with abdominal obesity417Multiple common co-morbidities produce left ventricular diastolic dysfunction associated with coronary microvascular dysfunction, oxidative stress and myocardial stiffening418Investigating the cardiovascular effects of antiretroviral drugs in a lean and high fat/sucrose diet rat model of obesity419Statins in the treatment of non-alcoholic steatohepatitis (NASH). Our experience from a 2-year prospective study in Constanta County, Romania420Epicardial adipose tissue as a predictor of cardiovascular outcome in patients with ACS undergoing PCI?Arterial and pulmonary hypertension423Dependence between heart rhythm disorers and ID polymorphism of ACE gene in hypertensive patients424Molecular mechanisms underlying the beneficial effects of Urocortin 2 in pulmonary arterial hypertension425Inhibition of TGf-b axis and action of renin-angiotensin system in human ascending aorta aneurysms426Early signs of microcirculation and macrocirculation abnormalities in prehypertension427Vascular smooth muscle cell-expressed Tie-2 controls vascular tone428Cardiac and vascular remodelling in the development of chronic thrombo-embolic pulmonary hypertension in a novel swine modelBiomarkers431Arrhythmogenic cardiomyopathy: a new, non invasive biomarker432Can circulating microRNAs distinguish type 1 and type 2 myocardial infarction?433Design of a high-throughput multiplex proteomics assay to identify left ventricular diastolic dysfunction in diabetes434Monocyte-derived and P-selectin-carrying microparticles are differently modified by a low fat diet in patients with cardiovascular risk factors who will and who will not develop a cardiovascular event435Red blood cell distribution width assessment by polychromatic interference microscopy of thin films in chronic heart failure436Invasive and noninvasive evaluation of quality of radiofrequency-induced cardiac denervation in patients with atrial fibrillation437The effect of therapeutic hypothermia on the level of brain derived neurotrophic factor (BDNF) in sera following cardiopulmonary resustitation438Novel biomarkers to predict outcome in patients with heart failure and severe aortic stenosis439Biological factors linking depression and anxiety to cardiovascular disease440Troponins and myoglobin dynamic at coronary arteries graftingInvasive, non-invasive and molecular imaging443Diet composition effects on the genetic typing of the mouse ob mutation: a micro-ultrasound characterization of cardiac function, macro and micro circulation and liver steatosis444Characterization of pig coronary and rabbit aortic lesions using IV-OCT quantitative analysis: correlations with histologyGene therapy and cell therapy447Enhancing the survival and angiogenic potential of mouse atrial mesenchymal cells448VCAM-1 expression in experimental myocardial infarction and its relation to bone marrow-derived mononuclear cell retentionTissue engineering451Advanced multi layered scaffold that increases the maturity of stem cell-derived human cardiomyocytes452Response of engineered heart tissue to simulated ischemia/reperfusion in the presence of acute hyperglycemic conditions453Serum albumin hydrogels prevent de-differentiation of neonatal cardiomyocytes454A novel paintbrush technique for transfer of low viscosity ultraviolet light curable cyan methacrylate on saline immersed in-vitro sheep heart. Cardiovasc Res 2016. [DOI: 10.1093/cvr/cvw149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Clearance of persistent hepatitis C virus infection in humanized mice using a claudin-1-targeting monoclonal antibody. Nat Biotechnol 2015; 33:549-554. [PMID: 25798937 PMCID: PMC4430301 DOI: 10.1038/nbt.3179] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 12/22/2014] [Indexed: 12/12/2022]
Abstract
Hepatitis C virus (HCV) infection is a leading cause of liver cirrhosis and cancer1. Cell entry of HCV2 and other pathogens3-5 is mediated by tight junction (TJ) proteins, but successful therapeutic targeting of TJ proteins has not been reported yet. Using a human liver-chimeric mouse model6 we show that a monoclonal antibody specific for TJ protein claudin-17 eliminates chronic HCV infection without detectable toxicity. This antibody inhibits HCV entry, cell-cell transmission and virus-induced signaling events. Antibody treatment reduces the number of HCV-infected hepatocytes in vivo, highlighting the need for de novo infection via host entry factors to maintain chronic infection. In summary, we demonstrate that an antibody targeting a virus receptor can cure chronic viral infection and uncover TJ proteins as targets for antiviral therapy.
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A dual role for hypoxia inducible factor-1α in the hepatitis C virus lifecycle and hepatoma migration. J Hepatol 2012; 56:803-9. [PMID: 22178269 PMCID: PMC3343261 DOI: 10.1016/j.jhep.2011.11.018] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 10/25/2011] [Accepted: 11/14/2011] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Hepatitis C virus (HCV) causes progressive liver disease and is a major risk factor for the development of hepatocellular carcinoma (HCC). However, the role of infection in HCC pathogenesis is poorly understood. We investigated the effect(s) of HCV infection and viral glycoprotein expression on hepatoma biology to gain insights into the development of HCV associated HCC. METHODS We assessed the effect(s) of HCV and viral glycoprotein expression on hepatoma polarity, migration and invasion. RESULTS HCV glycoproteins perturb tight and adherens junction protein expression, and increase hepatoma migration and expression of epithelial to mesenchymal transition markers Snail and Twist via stabilizing hypoxia inducible factor-1α (HIF-1α). HIF-1α regulates many genes involved in tumor growth and metastasis, including vascular endothelial growth factor (VEGF) and transforming growth factor-beta (TGF-β). Neutralization of both growth factors shows different roles for VEGF and TGFβ in regulating hepatoma polarity and migration, respectively. Importantly, we confirmed these observations in virus infected hepatoma and primary human hepatocytes. Inhibition of HIF-1α reversed the effect(s) of infection and glycoprotein expression on hepatoma permeability and migration and significantly reduced HCV replication, demonstrating a dual role for HIF-1α in the cellular processes that are deregulated in many human cancers and in the viral life cycle. CONCLUSIONS These data provide new insights into the cancer-promoting effects of HCV infection on HCC migration and offer new approaches for treatment.
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Key Words
- bc, bile canaliculi
- cmfda, 5-chloromethylfluorescein diacetate
- hcc, hepatocellular carcinoma
- emt, epithelial to mesenchymal transition
- hcvcc, hepatitis c virus cell culture
- hif-1α, hypoxia inducible factor 1 alpha
- jfh-1, japanese fulminant hepatitis-1
- mrp-2, multidrug resistant protein-2
- phh, primary human hepatocytes
- sr-bi, scavenger receptor class b member 1
- tgfβ, transforming growth factor-beta
- tnfα, tumor necrosis factor alpha
- vegf, vascular endothelial growth factor
- vsv-g, vesicular stomatitis virus glycoprotein
- hepatitis c
- hypoxia
- invasion
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Monoclonal anti-claudin 1 antibodies prevent hepatitis C virus infection of primary human hepatocytes. Gastroenterology 2010; 139:953-64, 964.e1-4. [PMID: 20685314 DOI: 10.1053/j.gastro.2010.05.073] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Revised: 05/12/2010] [Accepted: 05/24/2010] [Indexed: 12/24/2022]
Abstract
BACKGROUND & AIMS Hepatitis C virus (HCV) infection is a challenge to prevent and treat because of the rapid development of drug resistance and escape. Viral entry is required for initiation, spread, and maintenance of infection, making it an attractive target for antiviral strategies. The tight junction protein claudin-1 (CLDN1) has been shown to be required for entry of HCV into the cell. METHODS Using genetic immunization, we produced 6 monoclonal antibodies against the host entry factor CLDN1. The effects of antibodies on HCV infection were analyzed in human cell lines and primary human hepatocytes. RESULTS Competition and binding studies demonstrated that antibodies interacted with conformational epitopes of the first extracellular loop of CLDN1; binding of these antibodies required the motif W(30)-GLW(51)-C(54)-C(64) and residues in the N-terminal third of CLDN1. The monoclonal antibodies against CLDN1 efficiently inhibited infection by HCV of all major genotypes as well as highly variable HCV quasispecies isolated from individual patients. Furthermore, antibodies efficiently blocked cell entry of highly infectious escape variants of HCV that were resistant to neutralizing antibodies. CONCLUSIONS Monoclonal antibodies against the HCV entry factor CLDN1 might be used to prevent HCV infection, such as after liver transplantation, and might also restrain virus spread in chronically infected patients.
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Abstract
Viruses initiate infection by attaching to molecules or receptors at the cell surface. Hepatitis C virus (HCV) enters cells via a multistep process involving tetraspanin CD81, scavenger receptor class B member I, and the tight junction proteins Claudin-1 and Occludin. CD81 and scavenger receptor class B member I interact with HCV-encoded glycoproteins, suggesting an initial role in mediating virus attachment. In contrast, there are minimal data supporting Claudin-1 association with HCV particles, raising questions as to its role in the virus internalization process. In the present study we demonstrate a relationship between receptor active Claudins and their association and organization with CD81 at the plasma membrane by fluorescence resonance energy transfer and stoichiometric imaging methodologies. Mutation of residues 32 and 48 in the Claudin-1 first extracellular loop ablates CD81 association and HCV receptor activity. Furthermore, mutation of the same residues in the receptor-inactive Claudin-7 molecule enabled CD81 complex formation and virus entry, demonstrating an essential role for Claudin-CD81 complexes in HCV infection. Importantly, Claudin-1 associated with CD81 at the basolateral membrane of polarized HepG2 cells, whereas tight junction-associated pools of Claudin-1 demonstrated a minimal association with CD81. In summary, we demonstrate an essential role for Claudin-CD81 complexes in HCV infection and their localization at the basolateral surface of polarized hepatoma cells, consistent with virus entry into the liver via the sinusoidal blood and association with basal expressed forms of the receptors.
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Hepatitis C virus infection reduces hepatocellular polarity in a vascular endothelial growth factor-dependent manner. Gastroenterology 2010; 138:1134-42. [PMID: 19944696 PMCID: PMC4794984 DOI: 10.1053/j.gastro.2009.11.047] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2009] [Revised: 11/08/2009] [Accepted: 11/18/2009] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Hepatitis C virus (HCV) infection leads to progressive liver disease, frequently culminating in fibrosis and hepatocellular carcinoma. The mechanisms underlying liver injury in chronic hepatitis C are poorly understood. This study evaluated the role of vascular endothelial growth factor (VEGF) in hepatocyte polarity and HCV infection. METHODS We used polarized hepatoma cell lines and the recently described infectious HCV Japanese fulminant hepatitis (JFH)-1 cell culture system to study the role of VEGF in regulating hepatoma permeability and HCV infection. RESULTS VEGF negatively regulates hepatocellular tight junction integrity and cell polarity by a novel VEGF receptor 2-dependent pathway. VEGF reduced hepatoma tight junction integrity, induced a re-organization of occludin, and promoted HCV entry. Conversely, inhibition of hepatoma expressed VEGF with the receptor kinase inhibitor sorafenib or with neutralizing anti-VEGF antibodies promoted polarization and inhibited HCV entry, showing an autocrine pathway. HCV infection of primary hepatocytes or hepatoma cell lines promoted VEGF expression and reduced their polarity. Importantly, treatment of HCV-infected cells with VEGF inhibitors restored their ability to polarize, showing a VEGF-dependent pathway. CONCLUSIONS Hepatic polarity is critical to normal liver physiology. HCV infection promotes VEGF expression that depolarizes hepatoma cells, promoting viral transmission and lymphocyte migration into the parenchyma that may promote hepatocyte injury.
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CD81 and claudin 1 coreceptor association: role in hepatitis C virus entry. J Virol 2008; 82:5007-20. [PMID: 18337570 PMCID: PMC2346731 DOI: 10.1128/jvi.02286-07] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Accepted: 02/27/2008] [Indexed: 02/07/2023] Open
Abstract
Hepatitis C virus (HCV) is an enveloped positive-stranded RNA hepatotropic virus. HCV pseudoparticles infect liver-derived cells, supporting a model in which liver-specific molecules define HCV internalization. Three host cell molecules have been reported to be important entry factors or receptors for HCV internalization: scavenger receptor BI, the tetraspanin CD81, and the tight junction protein claudin-1 (CLDN1). None of the receptors are uniquely expressed within the liver, leading us to hypothesize that their organization within hepatocytes may explain receptor activity. Since CD81 and CLDN1 act as coreceptors during late stages in the entry process, we investigated their association in a variety of cell lines and human liver tissue. Imaging techniques that take advantage of fluorescence resonance energy transfer (FRET) to study protein-protein interactions have been developed. Aequorea coerulescens green fluorescent protein- and Discosoma sp. red-monomer fluorescent protein-tagged forms of CD81 and CLDN1 colocalized, and FRET occurred between the tagged coreceptors at comparable frequencies in permissive and nonpermissive cells, consistent with the formation of coreceptor complexes. FRET occurred between antibodies specific for CD81 and CLDN1 bound to human liver tissue, suggesting the presence of coreceptor complexes in liver tissue. HCV infection and treatment of Huh-7.5 cells with recombinant HCV E1-E2 glycoproteins and anti-CD81 monoclonal antibody modulated homotypic (CD81-CD81) and heterotypic (CD81-CLDN1) coreceptor protein association(s) at specific cellular locations, suggesting distinct roles in the viral entry process.
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Amyloid peptides and ion channel function in Drosophila models of Alzheimer's disease. SEB EXPERIMENTAL BIOLOGY SERIES 2008; 60:79-92. [PMID: 18309788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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Neuronal nitric oxide synthase gene transfer decreases [Ca2+]i in cardiac sympathetic neurons. J Mol Cell Cardiol 2007; 43:717-25. [PMID: 17961591 DOI: 10.1016/j.yjmcc.2007.09.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2007] [Revised: 08/30/2007] [Accepted: 09/06/2007] [Indexed: 01/28/2023]
Abstract
Gene transfer of neuronal nitric oxide synthase (nNOS) can decrease cardiac sympathetic outflow and facilitate parasympathetic neurotransmission. The precise pathway responsible for nitric oxide (NO) mediated inhibition of sympathetic neurotransmission is not known, but may be related to NO-cGMP activation of cGMP-stimulated phosphodiesterase (PDE2) that enhances the breakdown of cAMP to deactivate protein kinase A (PKA), resulting in a decrease in Ca(2+) influx mediated exocytosis of the neurotransmitter. We investigated depolarization evoked Ca(2+) influx in nNOS gene transduced sympathetic neurons from stellate ganglia with a noradrenergic cell specific vector (Ad.PRS-nNOS or empty vector), and examined how nNOS gene transfer affected cAMP and cGMP levels in these neurons. We found that targeting nNOS into these sympathetic neurons reduced amplitudes of voltage activated Ca(2+) transients by 44%. nNOS specific inhibition by N-[(4S)-4-Amino-5-[(2-aminoetyl](amino] pentyl]-N'-nitroguanidine (AAAN) reversed this response. nNOS gene transfer also increased intracellular cGMP (47%) and decreased cAMP (29%). A PDE2 specific inhibitor Bay60-7557 reversed the reduction in cAMP caused by Ad.PRS-nNOS. These results suggest that neuronal NO modulates cGMP and PDE2 to regulate voltage gated intracellular Ca(2+) transients in sympathetic neurons. Therefore, we propose this as a possible key step involved in NO decreasing cardiac sympathetic neurotransmission.
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Nicotinic acetylcholine receptors as drug/chemical targets, contributions from comparative genomics, forward and reverse genetics. SEB EXPERIMENTAL BIOLOGY SERIES 2007; 58:93-113. [PMID: 17608238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
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The homeobox transcription factor Even-skipped regulates acquisition of electrical properties in Drosophila neurons. Neural Dev 2006; 1:3. [PMID: 17147779 PMCID: PMC1679800 DOI: 10.1186/1749-8104-1-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2006] [Accepted: 11/16/2006] [Indexed: 11/28/2022] Open
Abstract
Background While developmental processes such as axon pathfinding and synapse formation have been characterized in detail, comparatively less is known of the intrinsic developmental mechanisms that regulate transcription of ion channel genes in embryonic neurons. Early decisions, including motoneuron axon targeting, are orchestrated by a cohort of transcription factors that act together in a combinatorial manner. These transcription factors include Even-skipped (Eve), islet and Lim3. The perdurance of these factors in late embryonic neurons is, however, indicative that they might also regulate additional aspects of neuron development, including the acquisition of electrical properties. Results To test the hypothesis that a combinatorial code transcription factor is also able to influence the acquisition of electrical properties in embryonic neurons we utilized the molecular genetics of Drosophila to manipulate the expression of Eve in identified motoneurons. We show that increasing expression of this transcription factor, in two Eve-positive motoneurons (aCC and RP2), is indeed sufficient to affect the electrical properties of these neurons in early first instar larvae. Specifically, we observed a decrease in both the fast K+ conductance (IKfast) and amplitude of quantal cholinergic synaptic input. We used charybdotoxin to pharmacologically separate the individual components of IKfast to show that increased Eve specifically down regulates the Slowpoke (a BK Ca2+-gated potassium channel), but not Shal, component of this current. Identification of target genes for Eve, using DNA adenine methyltransferase identification, revealed strong binding sites in slowpoke and nAcRα-96Aa (a nicotinic acetylcholine receptor subunit). Verification using real-time PCR shows that pan-neuronal expression of eve is sufficient to repress transcripts for both slo and nAcRα-96Aa. Conclusion Taken together, our findings demonstrate, for the first time, that Eve is sufficient to regulate both voltage- and ligand-gated currents in motoneurons, extending its known repertoire of action beyond its already characterized role in axon guidance. Our data are also consistent with a common developmental program that utilizes a defined set of transcription factors to determine both morphological and functional neuronal properties.
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Contributions from Caenorhabditis elegans functional genetics to antiparasitic drug target identification and validation: nicotinic acetylcholine receptors, a case study. Int J Parasitol 2006; 36:617-24. [PMID: 16620825 DOI: 10.1016/j.ijpara.2006.01.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2005] [Revised: 01/16/2006] [Accepted: 01/30/2006] [Indexed: 10/24/2022]
Abstract
Following the complete sequencing of the genome of the free-living nematode, Caenorhabditis elegans, in 1998, rapid advances have been made in assigning functions to many genes. Forward and reverse genetics have been used to identify novel components of synaptic transmission as well as determine the key components of antiparasitic drug targets. The nicotinic acetylcholine receptors (nAChRs) are prototypical ligand-gated ion channels. The functions of these transmembrane proteins and the roles of the different members of their extensive subunit families are increasingly well characterised. The simple nervous system of C. elegans possesses one of the largest nicotinic acetylcholine receptor gene families known for any organism and a combination of genetic, microarray, physiological and reporter gene expression studies have added greatly to our understanding of the components of nematode muscle and neuronal nAChR subtypes. Chemistry-to-gene screens have identified five subunits that are components of nAChRs sensitive to the antiparasitic drug, levamisole. A novel, validated target acting downstream of the levamisole-sensitive nAChR has also been identified in such screens. Physiology and molecular biology studies on nAChRs of parasitic nematodes have also identified levamisole-sensitive and insensitive subtypes and further subdivisions are under investigation.
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Microarray methods in Drosophila neurobiology. INVERTEBRATE NEUROSCIENCE 2005; 5:189-95. [PMID: 16180035 DOI: 10.1007/s10158-005-0010-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Accepted: 08/16/2005] [Indexed: 10/25/2022]
Abstract
In the relatively short period since their development, DNA microarrays have been used increasingly in the study of genetic and cellular processes, thereby offering a genome-wide approach to gene expression studies. With the advent of genome sequencing programs for organisms from yeast to man, the number of organisms which now have ready-made commercial arrays continues to increase. Here, the principle of DNA microarrays is introduced, with particular attention being given to the role of this technology in studies of the nervous system of the fruitfly Drosophila melanogaster. The importance of experimental design and sample preparation, in line with minimum information about microarray experiment (MIAME) compliance, is emphasised. The technical platforms available to the Drosophila neurobiologist have been illustrated and a brief number of data analysis tools that are readily available reviewed.
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Abstract
Dynamic changes in synaptic connectivity and strength, which occur during both embryonic development and learning, have the tendency to destabilize neural circuits. To overcome this, neurons have developed a diversity of homeostatic mechanisms to maintain firing within physiologically defined limits. In this study, we show that activity-dependent control of mRNA for a specific voltage-gated Na+ channel [encoded by paralytic (para)] contributes to the regulation of membrane excitability in Drosophila motoneurons. Quantification of para mRNA, by real-time reverse-transcription PCR, shows that levels are significantly decreased in CNSs in which synaptic excitation is elevated, whereas, conversely, they are significantly increased when synaptic vesicle release is blocked. Quantification of mRNA encoding the translational repressor pumilio (pum) reveals a reciprocal regulation to that seen for para. Pumilio is sufficient to influence para mRNA. Thus, para mRNA is significantly elevated in a loss-of-function allele of pum (pum(bemused)), whereas expression of a full-length pum transgene is sufficient to reduce para mRNA. In the absence of pum, increased synaptic excitation fails to reduce para mRNA, showing that Pum is also necessary for activity-dependent regulation of para mRNA. Analysis of voltage-gated Na+ current (I(Na)) mediated by para in two identified motoneurons (termed aCC and RP2) reveals that removal of pum is sufficient to increase one of two separable I(Na) components (persistent I(Na)), whereas overexpression of a pum transgene is sufficient to suppress both components (transient and persistent). We show, through use of anemone toxin (ATX II), that alteration in persistent I(Na) is sufficient to regulate membrane excitability in these two motoneurons.
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Latrophilin is required for toxicity of black widow spider venom in Caenorhabditis elegans. Biochem J 2004; 378:185-91. [PMID: 14594448 PMCID: PMC1223931 DOI: 10.1042/bj20031213] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2003] [Revised: 10/14/2003] [Accepted: 10/31/2003] [Indexed: 11/17/2022]
Abstract
Black widow spider venom (BWSV) kills Caenorhabditis elegans after injection owing to the presence of heat- and detergent-sensitive components, which are high-molecular-mass latrotoxins. A C. elegans homologue of latrophilin/CIRL (calcium-independent receptor for latrotoxin), B0457.1, was identified and shown to have five conserved domains. RNAi (RNA interference) of this gene rendered C. elegans resistant to BWSV, whereas RNAi for CYP37A1 or a neurexin I homologue, and a deletion mutant of the related B0286.2 gene, had no effect on BWSV toxicity. The latrophilin RNAi mutants exhibit changes in defaecation cycle and alterations in drug sensitivity. These results demonstrate that latrophilin mediates the toxicity of BWSV and provide evidence for a physiological function of this receptor.
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