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Loss of Autophagy Disrupts Stemness of Ameloblast-Lineage Cells in Aging. J Dent Res 2024; 103:156-166. [PMID: 38058147 DOI: 10.1177/00220345231209931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023] Open
Abstract
Autophagy is one of the intracellular degradation pathways and maintains cellular homeostasis, regulating the stress response, cell proliferation, and signal transduction. To elucidate the role of autophagy in the maintenance of dental epithelial stem cells and the subsequent enamel formation, we analyzed autophagy-deficient mice in epithelial cells (Atg7f/f;KRT14-Cre mice), focusing on the influence of aging and stress environments. We also performed in vitro cell and organ culture experiments with an autophagy inhibitor. In young Atg7f/f;KRT14-Cre mice, morphological change was not obvious in maxillary incisors, except for the remarkable cell death in the stratum intermedium of the transitional stage. However, under stress conditions of hyperglycemia, the incisor color changed to white in diabetes Atg7f/f;KRT14-Cre mice. Regarding dental epithelial stem cells, the shape of the apical bud region of the incisor became irregular with age, and odontoma was formed in aged Atg7f/f;KRT14-Cre mice. In addition, the shape of apical bud culture cells of Atg7f/f;KRT14-Cre mice became irregular and enlarged atypically, with epigenetic changes during culture, suggesting that autophagy deficiency may induce tumorigenesis in dental epithelial cells. The epigenetic change and upregulation of p21 expression were induced by autophagy inhibition in vivo and in vitro. These findings suggest that autophagy is important for the regulation of stem cell maintenance, proliferation, and differentiation of ameloblast-lineage cells, and an autophagy disorder may induce tumorigenesis in odontogenic epithelial cells.
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Labile iron derived from autophagy-mediated ferritin degradation in cardiomyocytes under pressure overload increases myocardial oxidative stress and develops heart failure in mice. Eur Heart J 2021. [DOI: 10.1093/eurheartj/ehab724.0747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Introduction
Heart failure is the leading cause of morbidity and mortality in developed countries, and abnormal iron metabolism is common in patients with heart failure. While iron is essential for metabolic homeostasis, it can increase oxidative stress, such as lipid peroxidation resulting from the generation of harmful reactive hydroxyl radicals through the Fenton reaction. Iron is stored in ferritin, which consists of ferritin heavy (FTH1) and light chains. FTH1 has ferroxidase activity and sequestrates labile ferrous iron. Its protein expression is mediated through nuclear receptor coactivator 4 (NCOA4)-mediated autophagic degradation, known as ferritinophagy. However, the role of ferritinophagy in the stressed heart remains unclear.
Methods
Cardiomyocyte-specific NCOA4-deficient (KO) mice were generated and subjected to pressure overload by transverse aortic constriction to induce heart failure. Cardiac remodelling was assessed by echocardiography and histological and molecular analyses four weeks after the operation. Furthermore, lipid peroxidation was inhibited by its potent inhibitor, ferrostatin-1.
Results
Deletion of NCOA4 in mouse hearts did not affect cardiac phenotypes and FTH1 protein level at baseline but improved cardiac systolic function (Fractional shortening, control littermates 21.9% vs KO 45.9%) accompanied by the attenuation of ferritin degradation (The protein level of FTH1, controls 42.9% vs. KO 67.2% of sham-operated hearts) 4 weeks after pressure overload compared to the control littermates. The number of LC3B (a marker of an autophagosome)- and FTH1-positive dots (controls 2.64/103μm2 vs KO 0.30/103μm2) and that of LAMP2a (a marker of a lysosome)- and FTH1-positive dots (controls 3.68/103μm2 vs KO 1.77/103μm2) increased in TAC-operated control hearts, which was attenuated in TAC-operated NCOA4-deficient hearts. The ratio of ferrous iron to the FTH1 protein level, which represents the non-binding fraction of labile ferrous iron to FTH1, was higher in TAC-operated control hearts than in the sham-operated controls and TAC-operated NCOA4–deficient hearts. Although pressure overload increased the level of malondialdehyde, a marker for lipid peroxidation in control hearts, its level was reduced by deletion of NCOA4 (controls 1.12 nmol/mg vs KO 0.68 nmol/mg). Ferrostatin-1 significantly mitigated the development of pressure overload-induced dilated cardiomyopathy in wild-type mice (Fractional shortening, saline 21.4% vs ferrostatin-1 41.7%).
Conclusions
Pressure overload-induced ferritinophagy in cardiomyocytes increases myocardial labile iron pool and oxidative stress resulting in the development of heart failure in mice.
Funding Acknowledgement
Type of funding sources: Foundation. Main funding source(s): British heart foundation
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Phosphorylation of mitophagic receptor protein Bcl2-like protein 13 plays an important role in maintaining cardiac function under pressure overload. Eur Heart J 2020. [DOI: 10.1093/ehjci/ehaa946.3603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
The most prominent role for mitochondria is to supply the cell with metabolic energy in the form of ATP generated by oxidative phosphorylation. Therefore, the quality control of mitochondria is essential for the maintenance of normal cellular functions. Accumulation of damaged mitochondria is characteristic of various diseases including heart failure. Damaged mitochondria are removed by a mitochondria-specific autophagy, called mitophagy.
Recently, we identified Bcl2-like protein 13 (Bcl2-L-13) as a mammalian functional homolog of Atg32, which is an essential mitophagy receptor in yeast. Bcl2-L-13, localized in outer mitochondrial membrane, induces mitochondrial fragmentation and mitophagy in HEK293 cells. Bcl2-L-13 induces mitophagy through the binding with microtubule-associated protein 1A/1B-light chain 3 (LC3).
We attempted to elucidate the activation mechanism of Bcl2-L-13-mediated mitophagy. Ser272 is close to the LC3 interacting motif in Bcl2-L-13. Overexpression of Bcl2-L-13 induced its Ser/Thr phosphorylation in HEK293 cells. The phosphorylation level of Bcl2-L-13 S272A was significantly attenuated compared with wild-type Bcl2-L-13, suggesting Ser272 is one of the phosphorylation sites. GST-pull down assay revealed that Bcl2-L-13 S272A showed less ability for binding with LC3, while immunocytochemical analysis using anti-ATP synthase and anti-LC3B antibodies showed that the mutant induced less mitophagic activity.
Next, we generated sheep polyclonal antibody for the detection of Bcl2-L-13 phosphorylated at Ser272. The antibody recognized wild-type Bcl2-L-13 but not Bcl2-L-13 S272A mutant. The phosphorylation level of Bcl2-L-13 at Ser272 was upregulated in wild-type hearts 4 weeks after transverse aortic constriction (TAC). In order to examine the in vivo role of the phosphorylation, we generated Bcl2-L-13 S272A mutant knock-in mice. The mice showed no abnormal cardiac phenotypes at baseline. However, the knock-in mice showed significantly larger left ventricular end-diastolic and end-systolic dimensions and lower fractional shortening than wild-type mice 4 weeks after TAC.
Taken together, the phosphorylation of Ser272 in Bcl2-L-13 regulates its mitophagic activity and plays an important role in maintaining cardiac function under pressure overload.
Funding Acknowledgement
Type of funding source: Foundation. Main funding source(s): British Heart Foundation
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M271 A 37-YEAR-OLD MALE WITH NOD2 MUTATION. Ann Allergy Asthma Immunol 2020. [DOI: 10.1016/j.anai.2020.08.299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abstract
Glucose is an essential source of energy for mammalian cells and is transported into the cells by glucose transporters. There are 2 types of glucose transporters: one is a passive glucose transporter, GLUT (SLC2A), and the other is a sodium-dependent active glucose transporter, SGLT (SLC5A). We previously reported that the expression of GLUTs during tooth development is precisely and spatiotemporally controlled and that the glucose uptake mediated by GLUT1 plays a crucial role in early tooth morphogenesis and tooth size determination. This study aimed to clarify the localization and roles of SGLT1 and SGLT2 in murine ameloblast differentiation by using immunohistochemistry, immunoelectron microscopy, an in vitro tooth organ culture experiment, and in vivo administration of an inhibitor of SGLT1/2, phloridzin. SGLT1, which has high affinity with glucose, was immunolocalized in the early secretory ameloblasts and the ruffle-ended ameloblasts in the maturation stage. However, SGLT2, which has high glucose transport capacity, was observed in the stratum intermedium, papillary layer, and ameloblasts at the maturation stage and colocalized with Na+-K+-ATPase. The inhibition of SGLT1/2 by phloridzin in the tooth germs induced the disturbance of ameloblast differentiation and enamel matrix formation both in vitro (organ culture) and in vivo (mouse model). The expression of SGLT1 and SGLT2 was significantly upregulated in hypoxic conditions in the ameloblast-lineage cells. These findings suggest that the active glucose uptake mediated by SGLT1 and SGLT2 is strictly regulated and dependent on the intra- and extracellular microenvironments during tooth morphogenesis and that the appropriate passive and active glucose transport is an essential event in amelogenesis.
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1182The novel mitophagic receptor protein bcl2-like protein 13: new insights for the molecular mechanisms of the pathogenesis of heart disease. Eur Heart J 2019. [DOI: 10.1093/eurheartj/ehz748.0024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
Cardiac function highly depends on energy generated by mitochondria, which are injured by various stresses such as pressure overload or aging. Damaged mitochondria in failing hearts are removed by a mitochondria-specific autophagy, called mitophagy. Dysregulation of mitophagy is implicated in the pathogenesis of heart disease such as heart failure. Mitochondrial morphologies change continuously through actions of mitochondrial dynamics (fission and fusion) and mitophagy is closely associated with mitochondrial fission to make mitochondria engulfable size by autophagosomes.
Atg32 is an essential protein for mitophagy in yeast. Some molecules have been reported to be involved in mitophagy, such as Parkin, FUNDC1 and Bnip3l. However, no Atg32 homologue has been identified in mammalian cells. We hypothesized that an unknown mammalian mitophagy receptor will share the molecular features with Atg32. By screening a public protein database for Atg32 homologues, we identified Bcl-2-like protein 13 (Bcl2-L-13).
Initially, we examined the function of Bcl2-L-13 in cardiomyocytes from 1-day-old Wistar rats. Forty-eight hours after infection of cardiomyocytes with an adenoviral vector expressing Bcl2-L-13, mitochondrial fragmentation was induced. In contrast, knockdown of Bcl2-L-13 induced mitochondrial elongation.
We carried out further investigation into functions of Bcl2-L-13 using cell lines. Bcl2-L-13 is localized at the mitochondrial outer membrane and bound to LC3 through the WXXI motif and induced mitochondrial fragmentation and mitophagy. In Bcl2-L-13, the BH domains are important for mitochondrial fragmentation, while the WXXI motif facilitates mitophagy. Bcl2-L-13 induces mitochondrial fragmentation in the absence of Drp1 which is the master regulator of mitochondrial fission, while it induces mitophagy in Parkin-deficient cells.
Next, we investigated physiological function of Bcl2-L-13. Knockdown of Bcl2-L-13 attenuated CCCP (carbonyl cyanide m-chlorophenyl hydrazone)-induced fragmentation and mitophagy. CCCP upregulated the phosphorylation level of Bcl2-L-13 Ser272 and Ser272Ala mutant showed less ability for inducing mitophagy. Considering of these, phosphorylation of this protein may regulate its activity. Furthermore, Bcl2-L-13 completely restored mitophagy in atg32-deficient yeast, suggesting that Bcl2-L-13 is a mammalian functional homologue of Atg32.
Our findings thus offer novel insights into molecular mechanisms of the pathogenesis of heart disease.
Acknowledgement/Funding
British Heart Foundation
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Regnase-1, a ribonuclease, in cardiomyocytes regulates immune responses in the heart. J Mol Cell Cardiol 2018. [DOI: 10.1016/j.yjmcc.2018.05.133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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P861Positioning an ECG electrode to the dorsal side can record higher amplitude of diaphragmatic compound motor action potentials (CMAP) during cryoballoon ablation. Europace 2017. [DOI: 10.1093/ehjci/eux151.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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P1627Successful bipolar ablation for hypertrophic cardiomyopathy-related ventricular tachycardia with deep intramural circuits. Europace 2017. [DOI: 10.1093/ehjci/eux158.253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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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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Epitope analysis of Ara h 2 and Ara h 6: characteristic patterns of IgE-binding fingerprints among individuals with similar clinical histories. Clin Exp Allergy 2015; 45:471-84. [PMID: 25213872 DOI: 10.1111/cea.12407] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Revised: 07/15/2014] [Accepted: 08/14/2014] [Indexed: 11/29/2022]
Abstract
BACKGROUND Ara h 2 and Ara h 6 are moderately homologous and highly potent peanut allergens. OBJECTIVE To identify IgE-binding linear epitopes of Ara h 6, compare them to those of Ara h 2, and to stratify binding based on clinical histories. METHODS Thirty highly peanut-allergic subjects were stratified by clinical history. Sera were diluted to contain the same amount of anti-peanut IgE. IgE binding to overlapping 20-mer peptides of Ara h 2 and Ara h 6 was assessed using microarrays. RESULTS Each subject had a unique IgE-binding fingerprint to peptides; these data were coalesced into epitope binding. IgE from subjects with a history of more severe reactions (n = 19) had a smaller frequency of binding events (BEs) for both Ara h 2 (52 BEs of 152 (19X8epitopes) possible BEs and Ara h 6 (13 BEs of 133 (19X7 epitopes) possible BEs) compared to IgE from those with milder histories (n = 11) (Ara h 2: 47 BEs of 88 (11X8 epitopes) possible BEs, P < 0.01; Ara h 6: 25 BEs of 77 (11X7 epitopes) possible BEs, P < 0.001). Using an unsupervised hierarchal cluster analysis, subjects with similar histories tended to cluster. We have tentatively identified a high-risk pattern of binding to peptides of Ara h 2 and Ara h 6, predominantly in subjects with a history of more severe reactions (OR = 12.6; 95% CI: 2.0-79.5; P < 0.01). CONCLUSIONS AND CLINICAL RELEVANCE IgE from patients with more severe clinical histories recognize fewer linear epitopes of Ara h 2 and Ara h 6 than do subjects with milder reactions and bind these epitopes in characteristic patterns. Close examination of IgE binding to epitopes of Ara h 2 and Ara h 6 may have prognostic value.
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19Analysis of TSC2-deficient hearts revealed the importance of autophagy in not only the quality but also the quantity control of mitochondria. Cardiovasc Res 2014. [DOI: 10.1093/cvr/cvu076.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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The state of sea bathing after the Great East Japan Earthquake. ARCH MAL PROF ENVIRO 2013. [DOI: 10.1016/j.admp.2013.07.140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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The state of surfing in disaster affected areas after the Great East Japan Earthquake. ARCH MAL PROF ENVIRO 2013. [DOI: 10.1016/j.admp.2013.07.141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Cell dynamics in cervical loop epithelium during transition from crown to root: implications for Hertwig's epithelial root sheath formation. J Periodontal Res 2012; 48:262-7. [PMID: 22973989 DOI: 10.1111/jre.12003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/30/2012] [Indexed: 01/10/2023]
Abstract
BACKGROUND AND OBJECTIVE Some clinical cases of hypoplastic tooth root are congenital. Because the formation of Hertwig's epithelial root sheath (HERS) is an important event for root development and growth, we have considered that understanding the HERS developmental mechanism contributes to elucidate the causal factors of the disease. To find integrant factors and phenomenon for HERS development and growth, we studied the proliferation and mobility of the cervical loop (CL). MATERIAL AND METHODS We observed the cell movement of CL by the DiI labeling and organ culture system. To examine cell proliferation, we carried out immunostaining of CL and HERS using anti-Ki67 antibody. Cell motility in CL was observed by tooth germ slice organ culture using green fluorescent protein mouse. We also examined the expression of paxillin associated with cell movement. RESULTS Imaging using DiI labeling showed that, at the apex of CL, the epithelium elongated in tandem with the growth of outer enamel epithelium (OEE). Cell proliferation assay using Ki67 immunostaining showed that OEE divided more actively than inner enamel epithelium (IEE) at the onset of HERS formation. Live imaging suggested that mobility of the OEE and cells in the apex of CL were more active than in IEE. The expression of paxillin was observed strongly in OEE and the apex of CL. CONCLUSION The more active growth and movement of OEE cells contributed to HERS formation after reduction of the growth of IEE. The expression pattern of paxillin was involved in the active movement of OEE and HERS. The results will contribute to understand the HERS formation mechanism and elucidate the cause of anomaly root.
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Hepatocyte growth factor stimulates root growth during the development of mouse molar teeth. J Periodontal Res 2011; 47:81-8. [PMID: 21854395 DOI: 10.1111/j.1600-0765.2011.01407.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND OBJECTIVE It is well known that tooth root formation is initiated by the development of Hertwig's epithelial root sheath (HERS). However, relatively little is known about the regulatory mechanisms involved in root development. As hepatocyte growth factor (HGF) is one of the mediators of epithelial-mesenchymal interactions in rodent tooth, the objective of this study was to examine the effects of HGF on the root development of mouse molars. MATERIAL AND METHODS The HERS of mouse molars and HERS01a, a cell line originated from HERS, were used in this study. For detection of HGF receptors in vivo and in vitro, we used immunochemical procedures. Root development was assessed by implanting molar tooth germs along with HGF-soaked beads into kidney capsules, by counting cell numbers in HERS01a cell cultures and by performing a 5'-bromo-2'-deoxyuridine (BrdU) assay in an organ-culture system. RESULTS HGF receptors were expressed in the enamel epithelium of molar germs as well as in HERS cells. HGF stimulated root development in the transplanted tooth germs, the proliferation of HERS01a cells in culture and HERS elongation in the organ-culture system. Examination using BrdU revealed that cell proliferation in HERS was increased by treatment with HGF, especially that in the outer layer of HERS. This effect was down-regulated when antibody against HGF receptor was present in the culture medium. CONCLUSION Our results raise the possibility that HGF signaling controls root formation via the development of HERS. This study is the first to show that HGF is one of the stimulators of root development.
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9033 Multicenter evaluation of malignancy in small-sized lung adenocarcinomas: revision of variations among institutions and underestimation generated by tumor size on PET/CT values using a phantom study. EJC Suppl 2009. [DOI: 10.1016/s1359-6349(09)71746-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Differential regulation of liver-specific and ubiquitously-expressed genes in primary rat hepatocytes by the extracellular matrix. Cell Physiol Biochem 2001; 11:33-40. [PMID: 11275681 DOI: 10.1159/000047790] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Primary rat hepatocytes were cultured with an extracellular matrix (ECM) overlay, in order to investigate the effect of an ECM on gene expression in hepatocytes. When hepatocytes, isolated by the collagenase-perfusion method, were cultured on type I collagen-coated dishes, the mRNA levels of liver-specific genes (aldolase B, tyrosine aminotransferase and albumin) decreased continuously, while those of ubiquitously-expressed genes (glyceraldehyde 3-phosphate dehydrogenase and beta-actin) increased. When a dilute ECM derived from the Engelbreth-Holm-Swarm mouse sarcoma (an EHS gel) was added to the above hepatocytes 3 days after plating, the mRNA levels of liver-specific genes increased, while those of ubiquitously-expressed genes decreased. The effects of a rat liver biomatrix (a physiological ECM for rat hepatocytes) on gene expression in primary hepatocytes were similar to those of the EHS gel. A nuclear run-on assay, and 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole or actinomycin D treatments revealed that the transcriptional rates of liver-specific genes were enhanced by the EHS gel overlay, while the apparent stability of the corresponding mRNAs were unchanged. In contrast, the transcriptional rates of ubiquitously-expressed genes were not greatly affected by an EHS gel overlay, while the apparent stability of their mRNAs were decreased. These data suggest that the ECM plays an important role in the maintenance of the differentiated characteristics of primary hepatocytes by inducing the transcription of liver-specific genes and, also, by destabilizing the mRNAs of ubiquitously-expressed genes.
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Identification of rab7 as a melanosome-associated protein involved in the intracellular transport of tyrosinase-related protein 1. J Invest Dermatol 2001; 117:81-90. [PMID: 11442753 DOI: 10.1046/j.0022-202x.2001.01402.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The melanosome is a unique secretory granule of the melanocyte in which melanin pigments are synthesized by tyrosinase gene family glycoproteins. Melanogenesis is a highly regulated process because of its inherent toxicity. An understanding of the various regulatory mechanisms is important in delineating the pathophysiology involved in pigmentary disorders and melanoma. We have purified and analyzed the total melanosomal proteins from B16 mouse melanoma tumors in order to identify new proteins that may be involved in the control of the melanogenesis process. Melanosomal proteins were resolved by two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis, a predominant spot (27 kDa with isoelectric point 5.8-6.4) was excised and digested with cyanogen bromide, and the fragments were sequenced. Synthetic oligonucleotide primers were synthesized corresponding to the peptide sequences, and reverse transcriptase polymerase chain reaction amplification of total RNA from B16 cells was carried out. Sequencing of one of the polymerase-chain-reaction-mediated clones demonstrated 80%-97% sequence homology of 200 bp nucleotide with GTP-binding proteins at the 3'-untranslated region. GTP-binding assay on two-dimensional gels of melanosomal proteins showed the presence of several (five to six) small GTP-binding proteins, suggesting that small GTP-binding proteins are associated with the melanosome. Among the known GTP-binding proteins with similar molecular weight and isoelectric point ranges, rab3, rab7, and rab8 were found to be present in the melanosomal fraction by immunoblotting. Confocal immunofluorescence microscopy showed that rab7 is colocalized with the tyrosinase-related protein 1 around the perinuclear area as well as, in part, in the perikaryon, thereby suggesting that rab7 might be involved in the intracellular transport of tyrosinase-related protein 1. Tyrosinase-related protein 1 transport was blocked by the treatment of B16 cells with antisense oligonucleotide to rab7. We suggest (i) that rab7 is a melanosome-associated molecule, (ii) that tyrosinase-related protein 1 is present in late-endosome delineated granules, and (iii) that rab7 is involved in the transport of tyrosinase-related protein 1 from the late-endosome delineated granule to the melanosome.
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Abstract
We have hypothesized that calpain mediates myocardial injury induced by Ca(2+)overload. However, in vitro study demonstrated that the calcium requirement for calpain activation is around 10 microm, which is difficult to reach without the cell collapsing. Furthermore, because calpastatin is abundant in the myocardial cell, calpain may not be activated in physiological conditions. To elucidate whether calpain is activated by the calcium concentration reachable in myocardial living cells, we measured the calpain activity and the calcium concentration simultaneously in isolated guinea-pig cardiomyocytes. t-Butoxycarbonyl-Leu-Met-7-amino-4chlorimethylcoumarin (Boc-Leu-Met-CMAC), a fluorescent substrate of calpain, and/or fura red, a calcium indicator, were loaded into isolated cardiomyocytes together, and their fluorescence were measured separately. Intracellular Ca overload was induced by changing the superfusate from normal Tyrode solution to a sodium-free one. After changing the solution, fluorescence intensity of fura red and Boc-Leu-Met-CMAC did not change for a while, then fluorescence intensity of fura red began to rise. This was followed by the fluorescence intensity of Boc-Leu-Met-CMAC starting to rise 160+/-45 s after [Ca(2+)](i)increase. The relative fluorescence intensity of fura red increased to 1.37+/-0.32 folds of the control at the point that calpain became active. The calcium concentration at this point was estimated as 451 n m. These results indicate that calpain is activated by the slight rise of Ca concentration in intact cardiomyocytes.
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[Ca2+ -induced cell injury of cardiomyocyte]. CLINICAL CALCIUM 2001; 11:714-718. [PMID: 15775573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Pathogenesis of ischemia/reperfusion injury involves Ca(2+) -induced cell injury. Elevated intracellular Ca(2+) concentration at the reperfusion activates the Ca(2+) dependent protease, calpain and increases the generation of reactive oxygen species (ROS) in mitochondria, which cause cell injury in ischemia/reperfusion.
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FR167653, a cytokine-suppressive agent, reduces myocardial ischemia-reperfusion injury in rats. CYTOKINES, CELLULAR & MOLECULAR THERAPY 2000; 6:165-70. [PMID: 11565954 DOI: 10.1080/mccm.6.4.165.170] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
FR167653 inhibits the production of inflammatory cytokines such as interleukin-1beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha) in human monocytes in a dose-dependent manner. We examined the effects of FR167653 on the propagation of myocardial infarction resulting from coronary occlusion-reperfusion and the time course of expression of these cytokines in myocardial tissue in rats. Myocardial infarction was induced by coronary ligation for 20 minutes followed by 2 hours of reperfusion. Although hemodynamic parameters did not differ significantly during coronary occlusion-reperfusion, the size of the infarct was significantly reduced by intravenous administration of FR167653 before occlusion (p < 0.01). mRNA levels of IL-1beta and TNF-alpha assessed by the reverse-transcriptase polymerase chain reaction method were significantly increased during coronary occlusion-reperfusion in the ischemic myocardium. Treatment with FR167653, however, significantly reduced the increased expression of these cytokines. These results indicate that the expression of inflammatory cytokines increases in the ischemic-reperfused myocardium and that the inhibition of the increased expression of cytokines by FR167653 effectively reduces myocardial ischemia-reperfusion injury.
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Calcineurin inhibitor attenuates left ventricular hypertrophy, leading to prevention of heart failure in hypertensive rats. Circulation 2000; 102:2269-75. [PMID: 11056104 DOI: 10.1161/01.cir.102.18.2269] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND There is controversy regarding the contribution of calcineurin activation to the development of pressure-overload left ventricular (LV) hypertrophy and heart failure. The aim of this study was to explore whether the inhibition of calcineurin may prevent the transition to heart failure in hypertensive rats and, if so, to clarify in which developmental stage of LV hypertrophy calcineurin plays a key role. METHODS AND RESULTS Dahl salt-sensitive rats placed on an 8% NaCl diet from the age of 7 weeks (hypertensive rats) were randomized to no treatment (n=6) or treatment with the calcineurin inhibitor FK506 (1 mg x kg(-1) x d(-1)) from 8 weeks (FKE, n=7) or from 17 weeks (FKL, n=7). Rats placed on a 0.3% NaCl diet were defined as control rats (n=6). The administration of FK506 from 8 weeks attenuated, although it did not block, LV hypertrophy observed in the untreated rats and prevented the transition to heart failure. The development of LV fibrosis, however, was not attenuated by the administration of FK506 from 8 weeks. The administration of FK506 from 17 weeks brought no benefit for cardiac remodeling or LV function and failed to prevent heart failure. CONCLUSIONS Calcineurin inhibition, if started from the initial stage of pressure overload, attenuated the development of LV hypertrophy without any effect on LV fibrosis and prevented the transition to heart failure. The activation of calcineurin is involved in the development of LV hypertrophy but not of LV fibrosis, and this involvement may be crucial at the initial stage.
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Abstract
BACKGROUND Hyperthermia increases cardiac tolerance to ischemia/reperfusion injury and activates manganese superoxide dismutase (Mn-SOD), an intrinsic radical scavenger, in myocardium in a biphasic manner. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) induced a biphasic cardioprotection that corresponded to the activation of Mn-SOD. However, a direct association between Mn-SOD activation in myocardium and the acquisition of tolerance to ischemia/reperfusion injury induced by hyperthermia and the involvement of the cytokines in the signal transduction pathway for the hyperthermia-induced cardioprotection have not yet been elucidated. METHODS AND RESULTS Hyperthermia was induced in anesthetized rats by placement in a temperature-controlled water bath. At 0.5 and 72 hours after hyperthermia, ischemia was induced by occlusion of the left coronary artery for 20 minutes, followed by reperfusion for 48 hours. Inhibition of the increases in Mn-SOD content and activity 72 hours after hyperthermia by the administration of antisense oligodeoxynucleotides to Mn-SOD abolished the expected decrease in myocardial infarct size. The simultaneous administration of neutralizing antibodies to TNF-alpha and IL-1beta before hyperthermia abolished the biphasic cardioprotection and increase in Mn-SOD activity. CONCLUSIONS The increase in Mn-SOD activity mediated through the production of TNF-alpha and IL-1beta by whole-body hyperthermia is important in the acquisition of early- and late-phase cardioprotection against ischemia/reperfusion injury in rats.
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Single-strand conformation polymorphism analysis on the delta-sarcoglycan gene in Japanese patients with hypertrophic cardiomyopathy. Am J Cardiol 2000; 85:1315-8. [PMID: 10831946 DOI: 10.1016/s0002-9149(00)00762-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
To elucidate the etiology of hypertrophic cardiomyopathy (HC) in humans, we analyzed the delta-sarcoglycan gene (SG), which is reported to be the causal gene for HC in the Syrian hamster BIO14.6. We performed polymerase chain reaction (PCR) single-strand conformation polymorphism (SSCP) and nucleotide sequence analyses on the delta-SG in 102 patients with HC. SSCP was detected in exon 2 of the gene, but not in the other exons. The direct sequencing analysis of exon 2 revealed a C-->T substitution at nucleotide residue 84 (TAC-->TAT) with no amino acid alteration (Tyr-->Tyr). There were no significant differences in allele frequencies of C/T between the patients with HC and the control group. Patients with HC were classified into 4 subgroups: obstructive HC, nonobstructive HC, apical HC, and familial HC. The allele frequency of C/T polymorphism in each of these groups was compared with that of the control group. The obstructive HC group showed a significantly greater frequency of the allele T than in the control group (31.6% vs 15.1%, RR = 2.6, p = 0.023). No other significant differences were observed. Thus, amino acid alteration in delta-SG may not be a common cause of HC in Japanese patients.
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Abstract
Transcription of the aldolase B gene, AldB, in the liver is regulated by hormones such as insulin and glucagon. To characterize the elements that are responsive to these hormones in the upstream region of AldB, plasmids carrying various length of the upstream region of this gene were constructed and transfected to primary cultured rat hepatocytes. The promoter activities were gradually increased by progressive deletion of the 5'-upstream region, and high activities were observed for constructs carrying the sequence between -408 and -85 bp, suggesting the presence of suppressive element(s) in the upstream region of -409 bp. The transcription activities of the mutants containing the sequences between -228 and -85 bp were enhanced by insulin, and glucagon suppressed the transcription activities of those containing the sequence between -764 and -85 bp. Two sequence elements similar to the cAMP-responsive element (CRE), one from -89 to -82 bp and another from +13 to +20 bp, were found in the upstream sequence of the gene. The latter element is not functional because its deletion did not affect either the transcription efficiency or glucagon response. However, the deletion of the former element diminished both functions. A gel retardation assay showed that the nuclear factor binds to the former element, which was competitive with authentic CRE oligonucleotide but not with the mutant CRE one. These results suggest that the CRE-like element in the promoter region is prerequisite for both fundamental transcription efficiency of the gene and suppression by glucagon in hepatocytes.
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Sandwich configuration of type I collagen suppresses progesterone production in primary cultured porcine granulosa cells by reducing gene expression of cytochrome P450 cholesterol side-chain cleavage enzyme. Arch Biochem Biophys 2000; 376:117-23. [PMID: 10729197 DOI: 10.1006/abbi.1999.1688] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
When porcine granulosa cells were cultured on type I collagen (TIC)-coated dishes, progesterone was continuously secreted in the culture medium. However, when cells were overlaid with a TIC gel, progesterone production was decreased to 34% (day 3) and 16% (day 4) of the value measured for cells without the overlay. The effect of TIC gel overlay on cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc), which catalyzes the conversion of cholesterol to pregnenolone and is thought to be the rate-limiting enzyme in the conversion of cholesterol to progesterone, was examined. P450scc gene expression in cells overlaid with a TIC gel was decreased to 62% (day 3) and 36% (day 4) of the value measured for cells without the overlay. Amounts of P450scc were also reduced in the cells overlaid with a TIC gel. When pregnenolone, the direct precursor of progesterone, was added to the culture medium, the increase in progesterone production by cells overlaid with a TIC gel was much greater than that for cells without a TIC gel and a statistical difference in progesterone production was no longer observed between the two groups of cells. Treatment of the cells with human FSH (hFSH) enhanced progesterone production in a dose-dependent manner, irrespective of the presence of a TIC gel overlay. Moreover, hFSH induced P450scc gene expression in cells with and without a TIC gel overlay. These results indicate that a TIC gel overlay reduces progesterone production in granulosa cells via the suppression of P450scc gene expression. This supports the possibility that the existence of a TIC gel on the apical side of granulosa cells prevents the spontaneous luteinization of granulosa cells cultured on TIC-coated dishes. The fact that hFSH overcomes the suppressive effect of the TIC gel overlay on progesterone production may explain the mechanism for the subtle rise in serum progesterone concentration in the late follicle phase of the "in vitro fertilization" program.
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Abstract
We measured infarct size after coronary occlusion (30 min) and reperfusion (24 h) in genetic non-insulin-dependent Zucker diabetic fatty (ZDF) rats with and without 4-wk cholesterol feeding. Infarct size was similar in ZDF rats and lean control rats but was significantly larger in cholesterol-fed diabetic rats than in cholesterol-fed lean rats (P < 0.05). Plasma levels of glucose, insulin, and triglycerides were significantly higher in diabetic rats and were not influenced by cholesterol feeding. The increase in total plasma cholesterol induced by cholesterol feeding was significantly greater in diabetic rats than in lean rats (P < 0.05). A significant positive correlation was found between total plasma cholesterol and infarct size (P < 0.05). Myeloperoxidase activity, as an index of neutrophil accumulation, was significantly higher and expression of P-selectin was more marked in the ischemic myocardium of cholesterol-fed diabetic rats than of cholesterol-fed lean rats. Acetylcholine-induced endothelium-dependent relaxation (EDR) of aortic rings was markedly impaired in cholesterol-fed diabetic rats. Thus cholesterol feeding significantly exacerbated myocardial injury produced by coronary occlusion-reperfusion in non-insulin-dependent diabetic rats, possibly because of enhanced expression of P-selectin and impairment of EDR in the coronary bed.
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[Animal models of cardiomyopathy]. NIHON RINSHO. JAPANESE JOURNAL OF CLINICAL MEDICINE 2000; 58:233-9. [PMID: 10885320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Animal models of cardiomyopathy have been used in many studies for our understanding of the pathophysiology of this disease. Syrian hamster, BIO 14.6, one of the most widely used models of cardiomyopathy, was reported to be caused by large deletion in the exon 1 and the promoter region of the delta-sarcoglycan gene. Cardiac hypertrophy or heart failure has been induced in dogs, rabbits, rats and many other animals by various manipulations such as drugs, pressure and/or volume overload and chronic rapid pacing. Recently, transgenic or knockout mice were examined to investigate the pathogenesis and development of the disease. It is important to select appropriate models for the aim of the studies.
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Abstract
Given the essential role played by gap junctions in the coordination of cardiac muscle contraction, it is plausible that down-regulation of gap junctional conduction is in part responsible for the contractile dysfunction observed in hypertrophied and failing hearts. In the present study, we analyzed the expression and function of the gap junction protein, connexin43, in the ventricular myocardium of hereditary cardiomyopathic, Syrian BIO 14.6 hamsters. Immunoprecipitation and immunoblot analyses revealed that levels of tyrosine phosphorylated connexin43 were increased in BIO 14.6 hamsters at the late stage of congestive heart failure. Furthermore, the increased tyrosine phosphorylation was correlated with increased c-Src activity. The functional consequences of tyrosine phosphorylation of connexin43 in gap junction were assessed using transfected cells expressing constitutively active c-Src. It was found that constitutively active c-Src diminished propagation of Ca(2+) waves in HEK293 cells and reduced gap junctional conductance between pairs of cardiac myocytes. We, therefore, conclude that during the progression of cardiac dysfunction in the cardiomyopathic heart, gap junctional communication is reduced via c-Src-mediated tyrosine phosphorylation of connexin43.
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Inhibition of baroreflex vagal bradycardia by selective stimulation of arterial chemoreceptors in rats. Exp Physiol 1999; 84:897-906. [PMID: 10502657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
We reported recently that hypoxia inhibits baroreflex vagal bradycardia (BVB) in rats and that this inhibition persists following chemoreceptor denervation. However, since it is possible that hypoxia also affects the central processing of chemoreceptive input, the existence of chemoreceptor-mediated inhibition of BVB cannot be ruled out. Therefore, we have studied whether selective chemoreceptor activation affects BVB in normoxic conditions. In pentobarbital-urethane-anaesthetized, succinylcholine-immobilized, artificially ventilated rats, BVB was provoked by electrical stimulation of the aortic depressor nerve. Arterial chemoreceptors were selectively activated by intracarotid injection of a minute amount of sodium cyanide. Cyanide injection consistently increased blood pressure while changing heart rate variably. BVB was inhibited in a dose-dependent manner. This inhibition, as well as changes in blood pressure and heart rate, was abolished following transection of the carotid sinus nerve (CSN) ipsilateral to the injection. Spinal cord transection at the C2 level did not affect the inhibition. On the other hand, intracarotid cyanide had no effect on bradycardia elicited by electrical stimulation of a peripheral cut end of the cervical vagus nerve. We conclude that chemoreceptor activation definitely inhibits BVB and that this inhibition is mediated by the CSN, and predominantly occurs in the central nervous system. The possibility is suggested that severe hypoxia suppresses not only BVB but also the chemoreceptor-mediated inhibition of BVB, both via the direct, central action.
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Abstract
Epidemiologic investigations have shown that exercise reduces morbidity and mortality from coronary artery disease. In this study, using a rat model, we attempted to determine whether exercise can reduce ischemic injury to the heart and elucidate a mechanism for the cardioprotective effect of exercise. Results showed that exercise significantly reduced the magnitude of a myocardial infarction in biphasic manner. The time course for cardioprotection resembled that of the change in manganese superoxide dismutase (Mn-SOD) activity. The administration of the antisense oligodeoxyribonucleotide to Mn-SOD abolished the expected decrease in infarct size. We showed that the level of tumor necrosis factor alpha (TNF-alpha) and interleukin 1beta (IL-1beta) increased after exercise. The simultaneous administration of the neutralizing antibodies to the cytokines abolished the exercise-induced cardioprotection and the activation of Mn-SOD. Furthermore, TNF-alpha can mimic the biphasic pattern of cardioprotection and activation of Mn-SOD. An antioxidant completely abolished cardioprotection and the activation of Mn-SOD by exercise or the injection of TNF-alpha as well as exercise-induced increase in TNF-alpha and IL-1beta. The production of reactive oxygen species and endogenous TNF-alpha and IL-1beta induced by exercise leads to the activation of Mn-SOD, which plays major roles in the acquisition of biphasic cardioprotection against ischemia/reperfusion injury in rats.
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Expression of a marker for intracellular Trypanosoma cruzi amastigotes in extracellular spheromastigotes. Mol Biochem Parasitol 1999; 98:265-70. [PMID: 10080394 DOI: 10.1016/s0166-6851(98)00158-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Involvement of NF-Y in transcriptional regulation of the phospholamban gene. EUROPEAN JOURNAL OF BIOCHEMISTRY 1998; 258:744-51. [PMID: 9874243 DOI: 10.1046/j.1432-1327.1998.2580744.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To understand the transcriptional regulation of the phospholamban gene, we analyzed a 5'-upstream region of the gene. Using a series of deletion constructs, we demonstrated that the region from -96 bp to -78 bp, containing the CCAAT sequence, is essential for transcription of this gene. This region specifically bound to nuclear proteins extracted from rat hearts, and gel-shift assays using competitive oligonucleotides, antibodies and recombinant proteins showed that this region binds to the NF-YA and NF-YB, members of the CCAAT-binding nuclear protein family. This region-dependent transcription in cardiac myocytes transfected with antisense cDNAs encoding NF-YA and NF-YB was decreased to approximately 50% of that seen in cells transfected with the same sense cDNAs. We, therefore, conclude that the region from -96 bp to -78 bp plays a critical role in expression of the phospholamban gene, which is regulated by binding of the nuclear protein NF-Y.
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Synergistic induction by collagen and fibronectin of liver-specific genes in rat primary cultured hepatocytes. Arch Biochem Biophys 1998; 358:58-62. [PMID: 9750164 DOI: 10.1006/abbi.1998.0841] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The extracellular matrix plays an important role for maintaining liver functions. We examined the effects of type I collagen and fibronectin on the expression of liver-specific genes in rat primary hepatocytes. When primary culture hepatocytes were overlaid with a type I collagen-gel, the expression of liver-specific genes (tyrosine aminotransferase, aldolase B, and albumin) increased by 4-5 times, compared with not overlaid hepatocytes. In contrast, the expression of non-liver-specific genes (GAPDH and beta-actin) was suppressed under the same conditions. The addition of fibronectin together with type I collagen-gel further enhanced the expression of liver-specific genes by 1.4-1.8 times. The addition of GRGDS peptide instead of fibronectin with the collagen-gel had a similar effect on hepatic gene expression to that of fibronectin. Addition of fibronectin alone exhibited had no effect on gene expression. These results suggest that type I collagen and fibronectin synergistically induce liver-specific genes.
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[Malignant hyperthermia]. TANPAKUSHITSU KAKUSAN KOSO. PROTEIN, NUCLEIC ACID, ENZYME 1998; 43:1898-902. [PMID: 9788199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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Abstract
The gap junction protein connexin-43 is normally located at the intercalated discs of cardiac myocytes, and it plays a critical role in the synchronization of their contraction. The mechanism by which connexin-43 is localized within cardiac myocytes is unknown. However, localization of connexin-43 likely involves an interaction with the cytoskeleton; immunofluorescence microscopy showed that in cardiac myocytes, connexin-43 specifically colocalizes with the cytoskeletal proteins ZO-1 and alpha-spectrin. In transfected HEK293 cells, immunoprecipitation experiments using coexpressed epitope-tagged connexin-43 and ZO-1 indicated that ZO-1 links connexin-43 with alpha-spectrin. The domains responsible for the protein-protein interaction between connexin-43 and ZO-1 were identified using affinity binding assays with deleted ZO-1 and connexin-43 fusion proteins. Immunoblot analysis of associated proteins showed that the C-terminal domain of connexin-43 binds to the N-terminal domain of ZO-1. The role of this linkage in gap junction formation was examined by a dominant-negative assay using the N-terminal domain of ZO-1. Overexpression of the N-terminal domain of ZO-1 in connexin-43-expressing cells resulted in redistribution of connexin-43 from cell-cell interfaces to cytoplasmic structures; this intracellular redistribution of connexin-43 coincided with a loss of electrical coupling. We therefore conclude that the linkage between connexin-43 and alpha-spectrin, via ZO-1, may serve to localize connexin-43 at the intercalated discs, thereby generating functional gap junctions in cardiac myocytes.
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Hormonal regulation of aldolase B gene expression in rat primary cultured hepatocytes. Arch Biochem Biophys 1998; 350:291-7. [PMID: 9473304 DOI: 10.1006/abbi.1997.0527] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Gene expression of aldolase B, an important enzyme for glucose and fructose metabolism, is regulated by hormones. We examined direct effects of major hormones on aldolase B gene expression in rat primary cultured hepatocytes, in comparison with those on the gene expression of phospho(enol)pyruvate carboxykinase (PEPCK), a key enzyme for gluconeogenesis. Insulin, dexamethasone, and high concentration of glucose increased aldolase B mRNA abundance in the hepatocytes. Glucagon strongly suppressed aldolase B gene expression, and this hormone canceled the stimulative effects of insulin, dexamethasone, and high concentration of glucose. Epinephrine and thyroxine slightly reduced aldolase B mRNA abundance, but these hormones did not cancel the stimulative effects of insulin and dexamethasone. To the contrary, expression of PEPCK gene was suppressed by insulin, dexamethasone, and high concentration of glucose, and remarkably induced by glucagon. Glucagon rapidly suppressed aldolase B gene expression at the transcriptional level. Forskolin and dibutyryl cAMP mimicked the suppressive effect of glucagon on aldolase B gene expression. These results suggest that glucagon may be a key regulator of aldolase B gene transcription through a cAMP/protein kinase A-signaling pathway.
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Abstract
In excitable cells, intracellular Ca2+ is released via the ryanodine receptor from the intracellular Ca2+ storing structure, the sarcoplasmic reticulum. To determine whether this released Ca2+ propagates through gap junctions to neighboring cells and thereby constitutes a long range signaling network, we developed a cell system in which cells expressing both connexin-43 and ryanodine receptor are surrounded by cells expressing only connexin-43. When the ryanodine receptor in cells was activated by caffeine, propagation of Ca2+ from these caffeine-responsive cells to neighboring cells was observed with a Ca2+ imaging system using fura-2/AM. Inhibitors of gap junctional communication rapidly and reversibly abolished this propagation of Ca2+. Together with the electrophysiological analysis of transfected cells, the observed intercellular Ca2+ wave was revealed to be due to the reconstituted gap junction of transfected cells. We next evaluated the functional roles of cysteine residues in the extracellular loops of connexin-43 in gap junctional communication. Mutations of Cys54, Cys187, Cys192, and Cys198 to Ser showed the failure of Ca2+ propagation to neighboring cells in accordance with the electrical uncoupling between transfected cells, whereas mutations of Cys61 and Cys68 to Ser showed the same pattern as the wild type. [14C]Iodoacetamide labeling of free thiols of cysteine residues in mutant connexin-43s showed that two pairs of intramolecular disulfide bonds are formed between Cys54 and Cys192 and between Cys187 and Cys198. These results suggest that intercellular Ca2+ signaling takes place in cultured cells expressing connexin-43, leading to their own synchronization and that the extracellular disulfide bonds of connexin-43 are crucial for this process.
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Cloning and characterization of the 5'-upstream regulatory region of the Ca(2+)-release channel gene of cardiac sarcoplasmic reticulum. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 240:408-15. [PMID: 8841406 DOI: 10.1111/j.1432-1033.1996.0408h.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
To elucidate the transcriptional regulation mechanism for the Ca(2+)-release channel gene of the cardiac sarcoplasmic reticulum (RYR2), we isolated and analyzed the 5'-upstream flanking region of the gene. Sequence analysis indicated that the core promoter region lacks canonical TATA and CAAT boxes, but contains three overlapping GC boxes. A gel shift assay indicated that Sp1 binds to the region containing the GC boxes. Different 5'-deletion constructs in the 5'-flanking region of the RYR2 gene were fused to the luciferase gene, and their promoter activity in rat neonatal cardiac myocytes was subsequently determined. The results revealed the presence of a region containing positive regulatory elements in the 5'-flanking region. Analyses of substitutional mutations introduced into the GC boxes and the regulatory region indicated that in addition to the GC box located at -56 to -51, two regulatory elements (RYR2P1 and RYR2P2) are essential for the promoter activity. These results indicated that Sp1 and transcription factors that bind to RYR2P1 and RYR2P2 cooperatively enhance the expression of the RYR2 gene. In a transient transfection experiment involving promoter-luciferase gene constructs in skeletal muscle cells, we identified a negative regulatory region between positions -209 and -90 that represses the expression of the RYR2 gene in skeletal muscle cells.
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Abstract
The DNA sequence of a 5736-nucleotide (nt) Trypanosoma cruzi maxicircle fragment was determined. Sequence comparisons indicate that its 5' terminus is the homologue of the downstream portion of the NADH dehydrogenase subunit 7 gene and that its 3' region is homologous to the maxicircle unidentified reading frame II gene. The region between these two gene segments contains six additional genes that encode mitochondrial proteins, including ATPase subunit 6 (A6). Comparison of the A6 maxicircle DNA sequence with that of an A6 cDNA indicates that the A6 RNA is extensively edited throughout its length. A 49-nt sequence that could serve as template for transcription of a guide RNA for editing a segment of the A6 RNA was found in one of 24 minicircle variable regions sequenced. Moreover, the presence of an RNA having this sequence was demonstrated in an RNAse protection assay. This is the first identification of a guide RNA template in a T. cruzi minicircle. Taken together, our findings suggest that T. cruzi and Trypanosoma brucei brucei are phylogenetically closer to each other than they are to Leishmania tarentolae, despite the relative similarity of the life cycles of the latter and T. cruzi.
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Abstract
We investigated the cardiotoxic effects of cocaine and cocaethylene on the Ca2+ flux responsible for excitation-contraction coupling in isolated ventricular rat myocytes. We simultaneously measured intracellular Ca2+ transients and cell length in isolated cardiac myocytes loaded with a fluorescent Ca2+ indicator, indo-1, during electrical field stimulation at 1 Hz. The cell length was estimated by video dimension analysis. We also measured the activities of Ca2+ ATPase and Ca2+ release channels of cardiac sarcoplasmic reticulum membrane vesicles. Both cocaine and cocaethylene produced significant decreases in both peak intracellular Ca2+ and the cell-contraction rate in a dose-dependent manner. The K0.5 for the reduction of peak intracellular Ca2+ was 157.5 microM for cocaine, but 90.0 microM for cocaethylene. Both cocaethylene and cocaine inhibited neither Ca2+ ATPase nor Ca2+ release channel activity. These results demonstrate that cocaethylene has a more potent direct negative inotropic action on cardiomyocytes, without preventing Ca2+ flux through the cardiac sarcoplasmic reticulum membrane.
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Trypanosoma cruzi: interruption of both alleles of a gene encoding a protein containing 14-amino-acid repeats by targeted insertion of NEOr and HYGr. Exp Parasitol 1995; 81:529-35. [PMID: 8542994 DOI: 10.1006/expr.1995.1146] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In Trypanosoma cruzi approximately 90% of the 121- and 176-kDa cytoskeletal proteins encoded by the two alleles of the TCR27 gene is composed of 14-amino-acid repeats. To gain insight into the function of the TCR27 proteins we replaced the corresponding regions of 42-nucleotide repeats in the two alleles with the NEOr and HYGr genes. Analyses of DNAs and RNAs from four clones resistant to both G418, a neomycin analogue, and hygromycin showed that in both cases the repetitive regions had in fact been deleted. In addition, the absence of expression of the 14-amino-acid repeats was confirmed in Western blots. In axenic cultures growth rates of the morphologically unchanged, doubly resistant organisms were not different from those of wild-type parasites. However, the doubly resistant organisms proliferated more slowly in cultured mammalian cells than did wild-type parasites. These findings indicate that the absence of the TCR27 repetitive regions is detrimental, but not fatal, to the parasites.
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Interleukin-6 down-regulates expressions of the aldolase B and albumin genes through a pathway involving the activation of tyrosine kinase. Arch Biochem Biophys 1995; 320:203-9. [PMID: 7625825 DOI: 10.1016/0003-9861(95)90001-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Interleukin-6 plays a key role in mediating acute-phase protein synthesis in hepatocytes. However, the mechanism of how interleukin-6 regulates aldolase B and albumin syntheses in hepatocytes is not completely understood. In this study, using primary cultured rat hepatocytes, we have shown that interleukin-6 down-regulates expressions of the aldolase B and albumin genes in a dose- and time-dependent manner. We examined whether the decrease in aldolase B and albumin mRNA expressions by interleukin-6 reflected transcriptional down-regulation or stability of the mRNA. Actinomycin D and cycloheximide did not affect the interleukin-6-mediated decrease in the expressions of both genes. These results suggest that the decreased expressions of both genes induced by interleukin-6 is controlled at the transcriptional level, and that it is due neither to increased degradation of mRNA nor to synthesis of new proteins. Protein kinases play a fundamental role in the intracellular signal transduction. To examine the interleukin-6 signal pathway(s) leading to the decrease of aldolase B and albumin mRNA expressions, we tested various kinds of protein kinase inhibitors in this system. Herbimycin A, an inhibitor of tyrosine kinase(s), prevented the decrease in the expression of aldolase B and albumin mRNAs by interleukin-6. H-7, an inhibitor of protein kinase C, prevented the decrease in the expression of albumin mRNA by interleukin-6, but did not induce recovery of that of aldolase B mRNA. These results suggest that a tyrosine kinase(s) or a herbimycin A-sensitive kinase(s) constitutes a common pathway for interleukin-6-mediated reduction of aldolase B and albumin mRNA expressions and that distinct pathways exist for the modes of expression of the two mRNAs.
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[Molecular biological aspects for malignant hyperthermia]. MASUI. THE JAPANESE JOURNAL OF ANESTHESIOLOGY 1995; 44 Suppl:S108-S112. [PMID: 8544303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Abstract
In the liver of the fasted rat, the aldolase B (AldB) mRNA level decreased to about half of that of the control rat. When the control rat was refed the glucose-rich diet, the AldB mRNA level increased about six to seven times more than in the fasted rat. This increase was shown as the activation of the AldB gene transcription by a nuclear run-on assay. To understand the causal factor(s) for this activation, the relationship between the AldB mRNA level in the liver and the plasma concentrations of hormones, which are known as major regulators of carbohydrate metabolism during fasting and refeeding, was investigated. The plasma insulin level in the rat which was refed the glucose-rich diet increased in parallel to AldB mRNA level, while the plasma glucagon level decreased reciprocally to it. The relationship of the plasma corticosterone level to the AldB mRNA level was not obvious. To directly confirm the effects of these hormones on AldB gene transcription in the liver, the responses of AldB gene in the primary cultured hepatocytes to these hormones were examined. Insulin and dexamethasone were effective to activate AldB gene, while glucagon and thyroxine were suppressive. Thyroxine did not extinguish the effects of insulin and dexamethasone, but glucagon canceled them. Thus, it is probable that in vivo these hormones synergistically regulate the AldB gene transcription. In vitro transcription analysis of two AldB promoter constructs suggested that the proximal half of the AldB promoter (up to -92 bp from the transcription start site) is, at least in part, involved for this induction, and the distal half which contains liver-specific elements (-93 to -202 bp) is not involved. The possible explanation for the dietary regulation of aldolase B gene transcription in the liver is discussed.
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Thyroid hormone enhances Ca2+ pumping activity of the cardiac sarcoplasmic reticulum by increasing Ca2+ ATPase and decreasing phospholamban expression. J Mol Cell Cardiol 1994; 26:1145-54. [PMID: 7815458 DOI: 10.1006/jmcc.1994.1133] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Phospholamban is a putative suppressor of the Ca2+ ATPase of the cardiac sarcoplasmic reticulum. The level of mRNA encoding the Ca2+ ATPase has been shown to be increased, whereas the phospholamban mRNA level to be decreased in the ventricles obtained from hyperthyroid rabbits [Nagai R, Zarain-Herzberg A. Brandl CJ, Fujii J. Tada M. MacLennan DH, Alpert NR, Periasamy M. (1989) Proc Natl Acad Sci USA 86: 2966-2970]. The present study was designed to examine whether these effects of thyroid hormone on the expression of the Ca2+ ATPase and phospholamban are exerted directly on cardiac myocytes and whether the resultant incoordinate expression of these proteins alters Ca2+ pumping activity. We studied the levels of phospholamban and Ca2+ ATPase mRNA in primary isolated neonatal rat myocardial cells incubated with triiodothyronine (T3) for 3-48 h and the Ca2+ uptake activity of the microsomes prepared from the cells. Northern blot analysis showed that T3 decreased phospholamban mRNA levels to about a half of control in 24 h. On the other hand, Ca2+ ATPase mRNA gradually increased with time. EC50 for phospholamban mRNA expression was 2.5 x 10(-10) M which was approximately 10 times higher than that for the Ca2+ ATPase. T3 increased Vmax of Ca2+ uptake with the significant reduction of K0.5 for Ca2+ (0.40 +/- 0.02 microM for control v 0.31 +/- 0.02 microM for T3-treated vesicles), indicating that thyroid hormone stimulates Ca2+ pumping activity not only by increasing the Ca2+ ATPase but also decreasing phospholamban. These results suggested that phospholamban regulates the Ca2+ ATPase in dual modes; in short time range, by decreasing the affinity of the Ca2+ ATPase for Ca2+ by phosphorylation of phospholamban with cAMP-dependent protein kinase, and in long time range, by changing the molecular ratio between the two proteins through the regulation of gene expression.
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A novel growth-inducible gene that encodes a protein with a conserved cold-shock domain. Nucleic Acids Res 1994; 22:2036-41. [PMID: 8029009 PMCID: PMC308118 DOI: 10.1093/nar/22.11.2036] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
We have isolated a cDNA that encodes a novel member of the Y-box binding protein family, termed as RYB-a (Rat Y-box Binding protein-a). RYB-a is a 31 kDa protein that contains a conserved cold-shock domain and an amino acid alignment similar to those of charge zipper proteins. Expression of RYB-a mRNA was highly abundant in the skeletal muscle, spleen, and fetal liver. The expression is very low in new-born and adult livers, suggesting its expression is under developmental regulation. In addition, the expression of RYB-a mRNA was induced in the liver during regeneration and by stimulation of quiescent fibroblast cells with serum. Induction in the fibroblasts was inhibited by treating the cell with a specific tyrosine kinase inhibitor, genistein or by detachment of cell-adhesion. Since both treatments are known to inhibit G1 cells to enter S phase, RYB-a gene is thought to be a member of growth-inducible genes.
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