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Sample records for cardiac sarcoplasmic reticulum

  1. Cardiac sarcoplasmic reticulum

    International Nuclear Information System (INIS)

    Jacobson, M.S.; Ambudkar, I.S.; Young, E.P.; Naseem, S.M.; Heald, F.P.; Shamoo, A.E.

    1985-01-01

    The effect on the cardiac sarcoplasmic reticulum of an atherogenic (1% cholesterol) diet fed during the neonatal vs the juvenile period of life was studied in Yorkshire swine. Male piglets were randomly assigned at birth to 1 of 4 groups: group I (control), group II (lactation feeding), group III (juvenile period feeding) and group IV (lactation and juvenile feeding). All animals were killed at 55 weeks of age and cardiac sarcoplasmic reticulum (SR) isolated for assay of calcium uptake, Ca 2+ -Mg 2+ ATPase activity, and lipid analysis by thin-layer chromatography and gas chromatography. The amount of cholesterol/mg SR protein and the cholesterol/phospholipid ratio were higher in the animals fed during lactation (groups II and IV) and lower in those fed only during the juvenile period (group III). Phospholipid fatty acid patterns as measured by gas chromatography were unaltered in any group. Calcium uptake was markedly diminished in all experimental conditions: group II 47%, group III 65% and group IV 96%. Compared to the observed changes in calcium transport, the ATP hydrolytic activity was relatively less affected. Only in group IV a significant decrease (41%) was seen. Groups II and III show no change in ATP hydrolytic activity. The decrease in calcium uptake and altered cholesterol/phospholipid ratio without effect on ATP hydrolytic activity is consistent with an uncoupling of calcium transport related to the atherogenic diet in early life. (author)

  2. Regulatory effects of phospholamban on cardiac sarcoplasmic reticulum function

    International Nuclear Information System (INIS)

    Kim, Hae Won.

    1989-01-01

    In this thesis, the author reports the effect of phospholamban on: (a) Ca 2+ release by cardiac SR and (b) the Ca 2+ -ATPase activity in a purified reconstituted system. Phosphorylation of phospholamban by Ca 2+ · calmodulin-dependent protein kinase had no appreciable effect on the initial rates of Ca 2+ release from cardiac SR vesicles loaded under passive conditions and on the apparent 45 Ca 2+ - 40 Ca 2+ exchange from cardiac SR vesicles loaded under active conditions. us, it appears that Ca 2+ · calmodulin-dependent phosphorylation of phospholamban is not involved in the regulation of Ca 2+ release and 45 Ca 2+-40 Ca 2+ exchange. To determine the molecular mechanism by which phospholamban regulates the Ca 2+ pump, a reconstituted system was developed, using a freeze-thaw sonication procedure. The Ca 2+ -ATPase was purified by a method which yields an active enzyme preparation essentially free of phospholamban. The best rates of Ca 2+ uptake were obtained when cholate and phosphatidylcholine (PC) were used at a ratio of cholate/PC/Ca 2 + -ATPase of 2/80/1. The maximal rates of Ca 2+ Uptake were 700 nmol/min/mg reconstituted vesicles compared to 800 nmol/min/mg SR vesicles. The EC 50 values for Ca 2+ were 0.05 μM for both Ca 2+ uptake and Ca 2+ -ATPase activity in the reconstituted vesicles compared to 0.63 μM Ca 2+ in native SR vesicles. To determine the effect of phospholamban on the Ca + -ATPase activity in the reconstituted vesicles, purified phospholamban was added to the cholate/Ca 2+ -ATPase mixture prior to combining it with liposomes

  3. Cardiac sarcoplasmic reticulum. Effects of an atherogenic diet during the neonatal and juvenile period

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, M S; Ambudkar, I S; Young, E P; Naseem, S M; Heald, F P; Shamoo, A E [Maryland Univ., College Park (USA). School of Medicine

    1985-04-01

    The effect on the cardiac sarcoplasmic reticulum of an atherogenic (1% cholesterol) diet fed during the neonatal vs the juvenile period of life was studied in Yorkshire swine. Male piglets were randomly assigned at birth to 1 of 4 groups: group I (control), group II (lactation feeding), group III (juvenile period feeding) and group IV (lactation and juvenile feeding). All animals were killed at 55 weeks of age and cardiac sarcoplasmic reticulum (SR) isolated for assay of calcium uptake, Ca/sup 2 +/-Mg/sup 2 +/ ATPase activity, and lipid analysis by thin-layer chromatography and gas chromatography. The amount of cholesterol/mg SR protein and the cholesterol/phospholipid ratio were higher in the animals fed during lactation (groups II and IV) and lower in those fed only during the juvenile period (group III). Phospholipid fatty acid patterns as measured by gas chromatography were unaltered in any group. Calcium uptake was markedly diminished in all experimental conditions: group II 47%, group III 65% and group IV 96%. Compared to the observed changes in calcium transport, the ATP hydrolytic activity was relatively less affected. Only in group IV a significant decrease (41%) was seen. Groups II and III show no change in ATP hydrolytic activity. The decrease in calcium uptake and altered cholesterol/phospholipid ratio without effect on ATP hydrolytic activity is consistent with an uncoupling of calcium transport related to the atherogenic diet in early life.

  4. Modulation of sarcoplasmic reticulum calcium release by calsequestrin in cardiac myocytes

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    SANDOR GYÖRKE

    2004-01-01

    Full Text Available Calsequestrin (CASQ2 is a high capacity Ca-binding protein expressed inside the sarcoplasmic reticulum (SR. Mutations in the cardiac calsequestrin gene (CASQ2 have been linked to arrhythmias and sudden death induced by exercise and emotional stress. We have studied the function of CASQ2 and the consequences of arrhythmogenic CASQ2 mutations on intracellular Ca signalling using a combination of approaches of reverse genetics and cellular physiology in adult cardiac myocytes. We have found that CASQ2 is an essential determinant of the ability of the SR to store and release Ca2+ in cardiac muscle. CASQ2 serves as a reservoir for Ca2+ that is readily accessible for Ca2+-induced Ca2+ release (CICR and also as an active Ca2+ buffer that modulates the local luminal Ca-dependent closure of the SR Ca2+ release channels. At the same time, CASQ2 stabilizes the CICR process by slowing the functional recharging of SR Ca2+ stores. Abnormal restitution of the Ca2+ release channels from a luminal Ca-dependent refractory state could account for ventricular arrhythmias associated with mutations in the CASQ2 gene.

  5. Effect of triorganotin compounds on calcium transport mechanisms in rat cardiac sarcoplasmic reticulum

    International Nuclear Information System (INIS)

    Cameron, J.A.; Kodavanti, P.R.S.; Yallapragada, P.R.; Desaiah, D.

    1990-01-01

    Although organotin compounds, in general, are neurotoxicants, recent studies indicate that these tin compounds affect heme metabolism as well as cardiovascular system. Sarcoplasmic reticulum (SR) calcium pump together with phosphorylation of phospholamban has an important role in myocardial contraction and relaxation. Since organotin compounds interfere with cardiovascular system, we have studied the in vitro as well as in vivo effects of tributyltin bromide (TBT), triethyltin bromide (TET) and trimethyltin chloride (TMT) on cardiac SR Ca 2+ -pump activity, in order to know the relative potency of these tin compounds. SR was isolated from heart ventricles of male Sprague-Dawley rats and used for in vitro studies. For in vivo studies, rats were treated orally in corn oil for 6 days with different doses of TET (0.5, 1.0 and 1.5 mg/kg/d), TMT (0.75, 1.5 and 2.5 mg/kg/d) and TBT (0.75, 1.5 and 2.5 mg/kg/d). Rats were sacrificed 24 hr after the last dosage and cardiac SR was prepared. Cardiac SR Ca 2+ -ATPase and 45 Ca-uptake were measured. All the three tin compounds inhibited Ca 2+ -ATPase and 45 Ca-uptake in vitro in a concentration dependent manner. The order of potency for Ca 2+ -ATPase as determined IC 50 , is TBT (2 uM) > TET (63 uM) > TMT (280 uM). For 45 Ca-uptake, if followed the same order i.e., TBT (0.35 uM) > TET (10 uM) > TMT (440 uM). In agreement with in vitro results, both SR Ca 2+ -ATPase and 45 Ca-uptake were significantly inhibited in rats treated with these tin compounds. These studies indicate that triorganotin compounds affect Ca 2+ -pumping mechanisms and thereby alter cardiac contraction-relaxation process

  6. Crosstalk between mitochondrial and sarcoplasmic reticulum Ca2+ cycling modulates cardiac pacemaker cell automaticity.

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    Yael Yaniv

    Full Text Available Mitochondria dynamically buffer cytosolic Ca(2+ in cardiac ventricular cells and this affects the Ca(2+ load of the sarcoplasmic reticulum (SR. In sinoatrial-node cells (SANC the SR generates periodic local, subsarcolemmal Ca(2+ releases (LCRs that depend upon the SR load and are involved in SANC automaticity: LCRs activate an inward Na(+-Ca(2+ exchange current to accelerate the diastolic depolarization, prompting the ensemble of surface membrane ion channels to generate the next action potential (AP.To determine if mitochondrial Ca(2+ (Ca(2+ (m, cytosolic Ca(2+ (Ca(2+ (c-SR-Ca(2+ crosstalk occurs in single rabbit SANC, and how this may relate to SANC normal automaticity.Inhibition of mitochondrial Ca(2+ influx into (Ru360 or Ca(2+ efflux from (CGP-37157 decreased [Ca(2+](m to 80 ± 8% control or increased [Ca(2+](m to 119 ± 7% control, respectively. Concurrent with inhibition of mitochondrial Ca(2+ influx or efflux, the SR Ca(2+ load, and LCR size, duration, amplitude and period (imaged via confocal linescan significantly increased or decreased, respectively. Changes in total ensemble LCR Ca(2+ signal were highly correlated with the change in the SR Ca(2+ load (r(2 = 0.97. Changes in the spontaneous AP cycle length (Ru360, 111 ± 1% control; CGP-37157, 89 ± 2% control in response to changes in [Ca(2+](m were predicted by concurrent changes in LCR period (r(2 = 0.84.A change in SANC Ca(2+ (m flux translates into a change in the AP firing rate by effecting changes in Ca(2+ (c and SR Ca(2+ loading, which affects the characteristics of spontaneous SR Ca(2+ release.

  7. Presence of a Ca2+-sensitive CDPdiglyceride-inositol transferase in canine cardiac sarcoplasmic reticulum

    International Nuclear Information System (INIS)

    Kasinathan, C.; Kirchberger, M.A.

    1988-01-01

    Sarcoplasmic reticulum (SR) and plasma membranes from canine left ventricle were used to evaluate the presence of the enzyme CDPdiglyceride-inositol transferase in these membranes. (K + ,-Ca 2+ )-ATPase activity, a marker for SR, was 79.2 +/- 5.0 (SE) and 11.2 +/- 2.0 μmol x mg -1 x h -1 in SR and plasma membrane preparations, respectively, and (Na + , K + )-ATPase activity, a marker for plasma membranes, was 5.6 +/- 1.2 and 99.2 +/- 8.0 μmol x mg -1 x h -1 , respectively. Contamination of SR and plasma membrane preparations by mitochondria was estimated to be 2% and 8%, respectively, and by Golgi membranes, 0.9% and 1.8%, respectively. The transferase activity detected in the plasma membrane preparation could be accounted for largely, but not entirely, by contaminating SR membranes. The pH optimum for the SR transferase activity was between 8.0 and 9.0. Ca 2+ inhibited the enzyme, half-maximal inhibition occurring at about 10 μM Ca 2+ . No loss of [ 3 H]PtdIns could be detected when membranes were incubated in the presence or absence of Ca 2+ . The Ca 2+ inhibition of the transferase was noncompetitive with respect to CDP-dipalmitin while that with respect to myo-inositol was slightly noncompetitive at low [Ca 2+ ] and became uncompetitive at higher [Ca 2+ ]. It is concluded that CDPdiglyceride-inositol transferase is present on SR membranes and is sensitive to micromolar Ca 2+ . The data are consistent with a putative role for the inhibition of the SR transferase by Ca 2+ and acidic pH in the protection of the SR against calcium overload in ischemic myocardium

  8. Effects of inorganic phosphate and ADP on calcium handling by the sarcoplasmic reticulum in rat skinned cardiac muscles.

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    Xiang, J Z; Kentish, J C

    1995-03-01

    The aim was to investigate whether, and how, increases in inorganic phosphate (Pi) and ADP, similar to those occurring intracellularly during early myocardial ischaemia, affect the calcium handling of the sarcoplasmic reticulum. Rat ventricular trabeculae were permeabilised with saponin. The physiological process of calcium induced calcium release (CICR) from the muscle sarcoplasmic reticulum was triggered via flash photolysis of the "caged Ca2+", nitr-5. Alternatively, calcium release was induced by rapid application of caffeine to give an estimate of sarcoplasmic reticular calcium loading. The initial rate of sarcoplasmic reticular calcium pumping was also assessed by photolysis of caged ATP at saturating [Ca2+]. Myoplasmic [Ca2+] (using fluo-3) and isometric force were measured. Pi (2-20 mM) significantly depressed the magnitude of CICR and the associated force transient. Sarcoplasmic reticular calcium loading was inhibited even more than CICR by Pi, suggesting that reduced calcium loading could account for all of the inhibitory effect of Pi on CICR and that Pi may slightly activate the calcium release mechanism. The reduced sarcoplasmic reticular calcium loading seemed to be due to a fall in the free energy of ATP hydrolysis (delta GATP) available for the calcium pump, since equal decreases in delta GATP produced by adding both Pi and ADP in various ratios caused similar falls in the calcium loading of the sarcoplasmic reticulum. The caged ATP experiments indicated that Pi (20 mM) did not affect the rate constant of sarcoplasmic reticular calcium uptake. ADP (10 mM) alone, or with 1 mM Pi, inhibited calcium loading. In spite of this, ADP (10 mM) did not alter CICR and, when 1 mM Pi was added, ADP increased CICR above control. An increase in intracellular Pi reduces sarcoplasmic reticular calcium loading and thus depresses the CICR. This could be an important contributing factor in the hypoxic or ischaemic contractile failure of the myocardium. However the

  9. Comparison of the calcium release channel of cardiac and skeletal muscle sarcoplasmic reticulum by target inactivation analysis

    International Nuclear Information System (INIS)

    McGrew, S.G.; Inui, Makoto; Chadwick, C.C.; Boucek, R.J. Jr.; Jung, C.Y.; Fleischer, S.

    1989-01-01

    The calcium release channel of sarcoplasmic reticulum which triggers muscle contraction in excitation-contraction coupling has recently been isolated. The channel has been found to be morphologically identical with the feet structures of the junctional face membrane of terminal cisternae and consists of an oligomer of a unique high molecular weight polypeptide. In this study, the authors compare the target size of the calcium release channel from heart and skeletal muscle using target inactivation analysis. The target molecular weights of the calcium release channel estimated by measuring ryanodine binding after irradiation are similar for heart (139,000) and skeletal muscle (143,000) and are smaller than the monomeric unit (estimated to be about 360,000). The target size, estimated by measuring polypeptide remaining after irradiation, was essentially the same for heart and skeletal muscle, 1,061,000 and 1,070,000, respectively, indicating an oligomeric association of protomers. Thus, the calcium release channel of both cardiac and skeletal muscle reacts uniquely with regard to target inactivation analysis in that (1) the size by ryanodine binding is smaller than the monomeric unit and (2) a single hit leads to destruction of more than one polypeptide, by measuring polypeptide remaining. The target inactivation analysis studies indicate that heart and skeletal muscle receptors are structurally very similar

  10. Decrease in sarcoplasmic reticulum calcium content, not myofilament function, contributes to muscle twitch force decline in isolated cardiac trabeculae

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    Milani-Nejad, Nima; Brunello, Lucia; Gyorke, Sándor; Janssen, Paul M.L.

    2014-01-01

    We set out to determine the factors responsible for twitch force decline in isolated intact rat cardiac trabeculae. The contractile force of trabeculae declined over extended periods of isometric twitch contractions. The force-frequency relationship within the frequency range of 4–8 Hz, at 37 °C, became more positive and the frequency optimum shifted to higher rates with this decline in baseline twitch tensions. The post-rest potentiation (37 °C), a phenomenon highly dependent on calcium handling mechanisms, became more pronounced with decrease in twitch tensions. We show that the main abnormality during muscle run-down was not due to a deficit in the myofilaments; maximal tension achieved using a K+ contracture protocol was either unaffected or only slightly decreased. Conversely, the sarcoplasmic reticulum (SR) calcium content, as assessed by rapid cooling contractures (from 27 °C to 0 °C), decreased, and had a close association with the declining twitch tensions (R2 ~ 0.76). SR Ca2+-ATPase, relative to Na+/Ca2+ exchanger activity, was not altered as there was no significant change in paired rapid cooling contracture ratios. Furthermore, confocal microscopy detected no abnormalities in the overall structure of the cardiomyocytes and t-tubules in the cardiac trabeculae (~23 °C). Overall, the data indicates that the primary mechanism responsible for force run-down in multi-cellular cardiac preparations is a decline in the SR calcium content and not the maximal tension generation capability of the myofilaments. PMID:25056841

  11. Temperature dependence of cardiac sarcoplasmic reticulum and sarcolemma in the ventricle of catfish (Clarias gariepinus

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    El-Sabry Abu-Amra

    2015-10-01

    The sarcolemmal Ca2+ contribution of activator Ca2+ was greater at a test temperature of 30 °C as assessed by verapamil. Whereas the SR-Ca2+ contribution was higher at 20 and 30 °C and a frequency rate of 0.2 and 0.4 Hz as assessed by caffeine and adrenaline, respectively. Bradykinin potentiating factor (BPF7 which was isolated from jelly fish (Cassiopea andromeda decreased the cardiac force developed at a frequency rate of 0.2 Hz and a temperature of 20 °C, whereas it increased the force developed at frequency rates of 0.2 and 0.4 Hz at 30 °C. These results indicate that BPF7 may act like verapamil in reducing the cardiac force through blocking the sarcolemmal Ca2+ channels at low temperature and like adrenaline in an increase of the cardiac force developed at warm temperature and the high frequency rate through stimulation of SR-Ca2+ activator. Therefore, this study indicates that the sarcolemmal Ca2+ influx and the SR-Ca2+ release contributors of activator Ca2+ for cardiac force development in the catfish heart were significantly greater at warm temperature and at the pacing frequency rates of 0.2 and 0.4 Hz as assessed by verapamil, adrenaline, caffeine and BPF7. However, the relative contribution of the sarcolemmal Ca2+ influx in the development of cardiac force in the catfish heart was greater than that of SR-Ca2+ release.

  12. Specific binding of (/sup 3/H)LY186126, an analogue of indolidan (LY195115), to cardiac membranes enriched in sarcoplasmic reticulum vesicles

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    Kauffman, R.F.; Utterback, B.G.; Robertson, D.W.

    1989-05-01

    LY186126 was found to be a potent inhibitor of type IV cyclic AMP phosphodiesterase located in the sarcoplasmic reticulum of canine cardiac muscle. This compound, a close structural analogue of indolidan (LY195115), was prepared in high specific activity, tritiated form to study the positive inotropic receptor(s) for cardiotonic phosphodiesterase inhibitors such as indolidan and milrinone. A high-affinity binding site for (/sup 3/H)LY186126 was observed (Kd = 4 nM) in purified preparations of canine cardiac sarcoplasmic reticulum vesicles. Binding was proportional to vesicle protein, was inactivated by subjecting membranes to proteolysis or boiling, and was dependent on added Mg2+. Scatchard analysis suggested the presence of a single class of binding sites in the membrane preparation. Indolidan, milrinone, and LY186126 (all at 1 microM) produced essentially complete displacement of bound (/sup 3/H)LY186126, while nifedipine, propranolol, and prazosin had little or no effect at this concentration. This represents the first reported use of a radioactive analogue to label the inotropic receptor for cardiotonic phosphodiesterase inhibitors. The results suggest that (/sup 3/H)LY186126 is a useful radioligand for examining the subcellular site(s) responsible for positive inotropic effects of these drugs.

  13. Specific binding of [3H]LY186126, an analogue of indolidan (LY195115), to cardiac membranes enriched in sarcoplasmic reticulum vesicles

    International Nuclear Information System (INIS)

    Kauffman, R.F.; Utterback, B.G.; Robertson, D.W.

    1989-01-01

    LY186126 was found to be a potent inhibitor of type IV cyclic AMP phosphodiesterase located in the sarcoplasmic reticulum of canine cardiac muscle. This compound, a close structural analogue of indolidan (LY195115), was prepared in high specific activity, tritiated form to study the positive inotropic receptor(s) for cardiotonic phosphodiesterase inhibitors such as indolidan and milrinone. A high-affinity binding site for [ 3 H]LY186126 was observed (Kd = 4 nM) in purified preparations of canine cardiac sarcoplasmic reticulum vesicles. Binding was proportional to vesicle protein, was inactivated by subjecting membranes to proteolysis or boiling, and was dependent on added Mg2+. Scatchard analysis suggested the presence of a single class of binding sites in the membrane preparation. Indolidan, milrinone, and LY186126 (all at 1 microM) produced essentially complete displacement of bound [ 3 H]LY186126, while nifedipine, propranolol, and prazosin had little or no effect at this concentration. This represents the first reported use of a radioactive analogue to label the inotropic receptor for cardiotonic phosphodiesterase inhibitors. The results suggest that [ 3 H]LY186126 is a useful radioligand for examining the subcellular site(s) responsible for positive inotropic effects of these drugs

  14. Cardiac function improved by sarcoplasmic reticulum Ca2+-ATPase overexpression in a heart failure model induced by chronic myocardial ischemia

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    Wei XIN

    2011-04-01

    Full Text Available Objective Chronic myocardial ischemia(CMI has become an important cause of heart failure(HF.The aim of present study was to examine the effects of Sarco-endoplasmic reticulum calcium ATPase(SERCA2a gene transfer in HF model in large animal induced by CMI.Methods HF was reproduced in minipigs by ligating the initial segment of proximal left anterior descending(LAD coronary artery with an ameroid constrictor to produce progressive vessel occlusion and ischemia.After confirmation of myocardial perfusion defect and cardiac function impairment by SPECT and echocardiography in the model,animals were divided into 4 groups: HF group;HF+enhanced green fluorescent protein(EGFP group;HF+SERCA2a group;and sham operation group as control.rAAV1-EGFP and rAAV1-SERCA2a(1×1012 vg for each animal were directly and intramyocardially injected to the animals of HF+EGFP and HF+SERCA2a groups.Sixty days after the gene transfer,the expression of SERCA2a at the protein level was examined by Western blotting and immunohistochemistry,the changes in cardiac function were determined by echocardiographic and hemodynamic analysis,and the changes in serum inflammatory and neuro-hormonal factors(including BNP,TNF-a,IL-6,ET-1 and Ang II were determined by radioimmunoassay.Results Sixty days after gene transfer,LVEF,Ev/Av and ±dp/dtmax increased significantly(P < 0.05,along with an increase of SERCA2a protein expression in the ischemic myocardium(PP < 0.05,accompanied by a significant decrease of inflammatory and neural-hormonal factors(PP < 0.05 in HF+SERCA2a group as compared with HF/HF+EGFP group.Conclusions Overexpression of SERCA2a may significantly improve the cardiac function of the ischemic myocardium of HF model induced by CMI and reverse the activation of neural-hormonal factors,implying that it has a potential therapeutic significance in CMI related heart failure.

  15. Phospholipid alterations in cardiac sarcoplasmic reticulum induced by xanthine oxidase: contamination of commercial preparations of xanthine oxidase by phospholipase A2

    International Nuclear Information System (INIS)

    Gamache, D.A.; Kornberg, L.J.; Bartolf, M.; Franson, R.C.

    1986-01-01

    Incubation of cardiac sarcoplasmic reticulum with xanthine oxidase alone at pH 7.0 resulted in a loss of lipid phosphorus that was potentiated by the addition of xanthine. Using autoclaved E.coli with 1- 14 C-oleate in the 2-acyl position of membrane phospholipids, the authors demonstrate that many, but not all, commercial preparations of xanthine oxidase contain significant phospholipase A 2 (PLA 2 ) activity (64.3-545.6 nmols/min/mg). The PLA 2 was maximally active in the neutral-alkaline pH range, was Ca 2+ -dependent, and was unaffected by the addition of xanthine. PLA 2 activity was totally inhibited by 1mM EDTA whereas radical production by optimal concentrations of xanthine/xanthine oxidase (X/XO) was unaffected by EDTA. Chromatographically purified xanthine oxidase (Sigma Grade III) contained high levels of PLA 2 activity (64.3 nmols/min/mg) compared to endogenous levels of neutral-active, Ca 2+ -dependent PLA 2 measured in various tissue homogenates (≤ 0.5 nmols/ min/mg). Because X/XO mixtures are used extensively to study oxygen free radical-induced cell injury and membrane phospholipid alterations, the presence of a potent extracellular PLA 2 may have influenced previously published reports, and such studies should be interpreted cautiously

  16. MicroRNAs and cardiac sarcoplasmic reticulum calcium ATPase-2 in human myocardial infarction: expression and bioinformatic analysis.

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    Boštjančič, Emanuela; Zidar, Nina; Glavač, Damjan

    2012-10-15

    Cardiac sarco(endo)plasmic reticulum calcium ATPase-2 (SERCA2) plays one of the central roles in myocardial contractility. Both, SERCA2 mRNA and protein are reduced in myocardial infarction (MI), but the correlation has not been always observed. MicroRNAs (miRNAs) act by targeting 3'-UTR mRNA, causing translational repression in physiological and pathological conditions, including cardiovascular diseases. One of the aims of our study was to identify miRNAs that could influence SERCA2 expression in human MI. The protein SERCA2 was decreased and 43 miRNAs were deregulated in infarcted myocardium compared to corresponding remote myocardium, analyzed by western blot and microRNA microarrays, respectively. All the samples were stored as FFPE tissue and in RNAlater. miRNAs binding prediction to SERCA2 including four prediction algorithms (TargetScan, PicTar, miRanda and mirTarget2) identified 213 putative miRNAs. TAM and miRNApath annotation of deregulated miRNAs identified 18 functional and 21 diseased states related to heart diseases, and association of the half of the deregulated miRNAs to SERCA2. Free-energy of binding and flanking regions (RNA22, RNAfold) was calculated for 10 up-regulated miRNAs from microarray analysis (miR-122, miR-320a/b/c/d, miR-574-3p/-5p, miR-199a, miR-140, and miR-483), and nine miRNAs deregulated from microarray analysis were used for validation with qPCR (miR-21, miR-122, miR-126, miR-1, miR-133, miR-125a/b, and miR-98). Based on qPCR results, the comparison between FFPE and RNAlater stored tissue samples, between Sybr Green and TaqMan approaches, as well as between different reference genes were also performed. Combing all the results, we identified certain miRNAs as potential regulators of SERCA2; however, further functional studies are needed for verification. Using qPCR, we confirmed deregulation of nine miRNAs in human MI, and show that qPCR normalization strategy is important for the outcome of miRNA expression analysis in human MI.

  17. Nitric oxide-dependent activation of CaMKII increases diastolic sarcoplasmic reticulum calcium release in cardiac myocytes in response to adrenergic stimulation.

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    Curran, Jerry; Tang, Lifei; Roof, Steve R; Velmurugan, Sathya; Millard, Ashley; Shonts, Stephen; Wang, Honglan; Santiago, Demetrio; Ahmad, Usama; Perryman, Matthew; Bers, Donald M; Mohler, Peter J; Ziolo, Mark T; Shannon, Thomas R

    2014-01-01

    Spontaneous calcium waves in cardiac myocytes are caused by diastolic sarcoplasmic reticulum release (SR Ca(2+) leak) through ryanodine receptors. Beta-adrenergic (β-AR) tone is known to increase this leak through the activation of Ca-calmodulin-dependent protein kinase (CaMKII) and the subsequent phosphorylation of the ryanodine receptor. When β-AR drive is chronic, as observed in heart failure, this CaMKII-dependent effect is exaggerated and becomes potentially arrhythmogenic. Recent evidence has indicated that CaMKII activation can be regulated by cellular oxidizing agents, such as reactive oxygen species. Here, we investigate how the cellular second messenger, nitric oxide, mediates CaMKII activity downstream of the adrenergic signaling cascade and promotes the generation of arrhythmogenic spontaneous Ca(2+) waves in intact cardiomyocytes. Both SCaWs and SR Ca(2+) leak were measured in intact rabbit and mouse ventricular myocytes loaded with the Ca-dependent fluorescent dye, fluo-4. CaMKII activity in vitro and immunoblotting for phosphorylated residues on CaMKII, nitric oxide synthase, and Akt were measured to confirm activity of these enzymes as part of the adrenergic cascade. We demonstrate that stimulation of the β-AR pathway by isoproterenol increased the CaMKII-dependent SR Ca(2+) leak. This increased leak was prevented by inhibition of nitric oxide synthase 1 but not nitric oxide synthase 3. In ventricular myocytes isolated from wild-type mice, isoproterenol stimulation also increased the CaMKII-dependent leak. Critically, in myocytes isolated from nitric oxide synthase 1 knock-out mice this effect is ablated. We show that isoproterenol stimulation leads to an increase in nitric oxide production, and nitric oxide alone is sufficient to activate CaMKII and increase SR Ca(2+) leak. Mechanistically, our data links Akt to nitric oxide synthase 1 activation downstream of β-AR stimulation. Collectively, this evidence supports the hypothesis that CaMKII is

  18. Detection, Properties, and Frequency of Local Calcium Release from the Sarcoplasmic Reticulum in Teleost Cardiomyocytes

    OpenAIRE

    Llach, Anna; Molina, Cristina E.; Alvarez Lacalle, Enrique; Tort, Lluis; Benítez, Raul; Hove, Leif

    2011-01-01

    Calcium release from the sarcoplasmic reticulum (SR) plays a central role in the regulation of cardiac contraction and rhythm in mammals and humans but its role is controversial in teleosts. Since the zebrafish is an emerging model for studies of cardiovascular function and regeneration we here sought to determine if basic features of SR calcium release are phylogenetically conserved. Confocal calcium imaging was used to detect spontaneous calcium release (calcium sparks and waves) from...

  19. Purification of a sarcoplasmic reticulum protein that binds Ca2+ and plasma lipoproteins

    International Nuclear Information System (INIS)

    Hofmann, S.L.; Brown, M.S.; Lee, E.; Pathak, R.K.; Anderson, R.G.; Goldstein, J.L.

    1989-01-01

    A protein in the sarcoplasmic reticulum of rabbit skeletal and cardiac muscle was identified because of its ability to bind 125I-labeled low density lipoprotein (LDL) with high affinity after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This protein, referred to as the 165-kDa protein, is restricted to striated muscle. It was not detected in 14 other tissues, including several that contain smooth muscle, but it appears in rat L6 myoblasts when they differentiate into myocytes. Immunofluorescence and immunoelectron microscopic studies revealed that the protein is present throughout the sarcoplasmic reticulum and the terminal cisternae. It binds 45Ca2+ on nitrocellulose blots and stains metachromatically with Stains-all, a cationic dye that stains Ca2+-binding proteins. It does not appear to be a glycoprotein, and it appears slightly larger than the 160-kDa glycoprotein previously described in sarcoplasmic reticulum. The 165-kDa protein binds LDL, beta-migrating very low density lipoprotein, and a cholesterol-induced high density lipoprotein particle that contains apoprotein E as its sole apoprotein with much higher affinity than it binds high density lipoprotein. The protein is stable to boiling and to treatment with sodium dodecyl sulfate, but it becomes sensitive to these treatments when its cystine residues are reduced and alkylated. The protein was purified 1300-fold to apparent homogeneity from rabbit skeletal muscle membranes. It differs from the cell surface LDL receptor in that (1) its apparent molecular weight is not changed by reduction and alkylation; (2) it is present in Watanabe-heritable hyperlipidemic rabbits, which lack functional LDL receptors; (3) binding of lipoproteins is not inhibited by EDTA; and (4) it is located within the lumen of the sarcoplasmic reticulum where it has no access to plasma lipoproteins

  20. Dynamic Changes in Sarcoplasmic Reticulum Structure in Ventricular Myocytes

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    Amanda L. Vega

    2011-01-01

    sarcoplasmic reticulum (SR and the sarcolemma where Ca2+ release is activated. Here, we tested the hypothesis that the SR is a structurally inert organelle in ventricular myocytes. Our data suggest that rather than being static, the SR undergoes frequent dynamic structural changes. SR boutons expressing functional ryanodine receptors moved throughout the cell, approaching or moving away from the sarcolemma of ventricular myocytes. These changes in SR structure occurred in the absence of changes in [Ca2+] during EC coupling. Microtubules and the molecular motors dynein and kinesin 1(Kif5b were important regulators of SR motility. These findings support a model in which the SR is a motile organelle capable of molecular motor protein-driven structural changes.

  1. Biochemical and morphological characterization of light and heavy sarcoplasmic reticulum vesicles

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, K.P.

    1978-01-01

    Light and heavy sarcoplasmic reticulum vesicles isolated from rabbit leg muscle have been used in a study of chloride-induced calcium release. The biochemical and morphological data indicate that light sarcoplasmic reticulum vesicles are derived from the longitudinal reticulum and heavy sarcoplasmic reticulum vesicles are derived from the terminal cisternae of the sarcoplasmic reticulum. The light and heavy sarcoplasmic reticulum vesicles were both able to accumulate calcium in the presence of ATP to amounts greater than 100 nmoles Ca/sup + +/ per mg of protein in less than one minute. Light and heavy sarcoplasmic reticulum vesicles each had a biphasic time course of calcium uptake. The initial uptake was followed by a rapid release after approximately one minute, of 30 to 40% of the accumulated calcium, which was then followed by a slower phase of calcium accumulation. Results indicate that the chloride induced release of calcium may be acting by two mechanisms, osmotic swelling and depolarization. The release of calcium from the light SR vesicles is probably due to osmotic swelling and the release of calcium from the heavy SR vesicles is probably due to depolarization.

  2. Porcine malignant hyperthermia susceptibility: hypersensitive calcium-release mechanism of skeletal muscle sarcoplasmic reticulum.

    Science.gov (United States)

    O'Brien, P J

    1986-01-01

    This study tested the hypothesis that calcium-release from sarcoplasmic reticulum isolated from malignant hyperthermia swine had abnormal concentration-dependency on release modulators. Halothane stimulated half-maximal calcium-release at similar concentrations for malignant hyperthermia and control sarcoplasmic reticulum (0.10 +/- 0.04 mM). However, concentrations causing half-maximal calcium-release were lower for malignant hyperthermia sarcoplasmic reticulum (P less than 0.001) by an order of magnitude for Ca2+ (28.1 +/- 8.3 versus 1.23 +/- 0.45 nM), adenosine triphosphate (0.33 +/- 0.09 versus 0.023 +/- 0.014 mM) and caffeine (7.79 +/- 1.56 versus 0.80 +/- 0.44 mM). Half-maximal inhibition by Mg2+ occurred at threefold higher concentrations for malignant hyperthermia sarcoplasmic reticulum (0.23 +/- 0.02 versus 0.78 +/- 0.17 mM). The Ca2+-sensitivity curves for calcium-release by sarcoplasmic reticulum isolated from heterozygotes for the malignant hyperthermia-defect were indistinguishable from the averages of the curves for controls and malignant hyperthermia-homozygotes. Results of this study suggest that malignant hyperthermia is initiated due to a hypersensitive calcium-release mechanism which is inherited in an autosomal, codominant pattern and may be diagnosed using calcium-release sensitivity-tests on isolated sarcoplasmic reticulum. Images Fig. 1. PMID:3742367

  3. Sarcoplasmic reticulum function in slow- and fast-twitch skeletal muscles from mdx mice.

    Science.gov (United States)

    Divet, Alexandra; Huchet-Cadiou, Corinne

    2002-08-01

    The aim of the present study was to establish whether alterations in sarcoplasmic reticulum function are involved in the abnormal Ca(2+) homeostasis of skeletal muscle in mice with muscular dystrophy ( mdx). The properties of the sarcoplasmic reticulum and contractile proteins of fast- and slow-twitch muscles were therefore investigated in chemically skinned fibres isolated from the extensor digitorum longus (EDL) and soleus muscles of normal (C57BL/10) and mdx mice at 4 and 11 weeks of development. Sarcoplasmic reticulum Ca(2+) uptake, estimated by the Ca(2+) release following exposure to caffeine, was significantly slower in mdx mice, while the maximal Ca(2+) quantity did not differ in either type of skeletal muscle at either stage of development. In 4-week-old mice spontaneous sarcoplasmic reticulum Ca(2+) leakage was observed in EDL and soleus fibres and this was more pronounced in mdx mice. In addition, the maximal Ca(2+)-activated tension was smaller in mdx than in normal fibres, while the Ca(2+) sensitivity of the contractile apparatus was not significantly different. These results indicate that mdx hindlimb muscles are affected differently by the disease process and suggest that a reduced ability of the Ca(2+)-ATPase to load Ca(2+) and a leaky sarcoplasmic reticulum membrane may be involved in the altered intracellular Ca(2+) homeostasis.

  4. Biochemical and morphological characterization of light and heavy sarcoplasmic reticulum vesicles

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, Kevin Peter [Univ. of Rochester, NY (United States)

    1978-01-01

    Light (30 to 32.5% sucrose) and heavy (38.5 to 42% sucrose) sarcoplasmic reticulum vesicles (LSR,HSR) were isolated from rabbit leg muscle using a combination of differential centrifugation and isopycnic zonal ultracentrifugation. Thin-section electron microscopy of LSR vesicles reveals empty vesicles of various sizes and shapes whereas the HSR vesicles appear as rounded vesicles of uniform size filled with electron dense material, similar to that seen in the terminal cisternae of the sarcoplasmic reticulum. The sucrose HSR vesicles have an additional morphological feature which appears as membrane projections that resemble the SR feet. The freeze-fracture morphology of either type of SR reveals an asymmetric distribution of intramembraneous particles in the same orientation and distribution as the sarcoplasmic reticulum in vivo. Biochemical studies were made on the content of Ca, Mg, ATPase, and protein of the vesicles and phosphorylation of the vesicles. The biochemical and morphological data indicate that the LSR is derived from the longitudinal sarcoplasmic reticulum and the HSR is derived from the terminal cisternae of the sarcoplasmic reticulum, contains junctional SR membrane and has three unique proteins (calsequestrin, an intrinsic 30,000 dalton protein and a 9000 dalton proteolipid).

  5. Calcium uptake by sarcoplasmic reticulum isolated from hearts of septic rats

    International Nuclear Information System (INIS)

    McDonough, K.H.

    1988-01-01

    Myocardial sarcoplasmic reticulum (SR) plays a critical role in the regulation of the cytosolic calcium fluctuations that occur during the cardiac cycle. One function of the SR is to lower the calcium concentration so that myocardial relaxation and thus ventricular filling can occur. The aim of the present study was to determine if hyperdynamic sepsis induced a decrease in the capacity of SR to take up calcium. This defect would result in decreased ventricular filling and thus decreased cardiac output, as has previously been shown in isolated perfused working hearts removed from septic rats. Therefore, rats were anesthetized with ether, and sepsis was induced by the injection of an aliquot of a fecal homogenate into the peritoneal cavity. Control animals either underwent surgery and received an aliquot of sterilized fecal inoculum (sham) or were untreated (no surgery). On day 2 after surgery, animals were anesthetized with pentobarbital, and hearts were removed, weighted, and SR isolated. The rate of uptake of 45 Ca 2+ by SR from septic rats was not depressed compared to controls but in fact was elevated. Maximum 45 Ca 2+ accumulated by the SR and Ca 2+ -stimulated ATPase activity were similar in SR from control and septic hearts. These results suggest that the contractile dysfunction noted in the myocardium in early sepsis is probably not due to inadequate SR removal of Ca 2+ during diastole

  6. Calcium uptake by sarcoplasmic reticulum in the presence of organophosphorus insecticide methyl-parathion

    International Nuclear Information System (INIS)

    Blasiak, J.

    1995-01-01

    Using an isotope labelling technique it has been shown that an organophosphorus insecticide methyl parathion (0,0-diethyl 0-4-nitrophenyl phosphorothionate) depressed calcium uptake by sarcoplasmic reticulum isolated from rabbit hind leg muscle. The effect was significant for insecticide concentrations of 50 and 100 μM and was dose-dependent. The insecticide exerted a more pronounced effect on calcium uptake in the presence of ATP in the reticulum environment than in the absence of ATP. The inhibitory action of methyl parathion on Ca 2+ accumulation by sarcoplasmic reticulum can cause a rise in myoplasmic free Ca 2+ , the essential prerequisite for contracture activation. Because methyl parathion, as well as other organophosphorus insecticides, is primarily neurotoxic, evidence of non-specific effect could be important for assessing its environmental safety. (author). 20 refs, 2 figs

  7. Methods for Creating and Animating a Computer Model Depicting the Structure and Function of the Sarcoplasmic Reticulum Calcium ATPase Enzyme.

    Science.gov (United States)

    Chen, Alice Y.; McKee, Nancy

    1999-01-01

    Describes the developmental process used to visualize the calcium ATPase enzyme of the sarcoplasmic reticulum which involves evaluating scientific information, consulting scientists, model making, storyboarding, and creating and editing in a computer medium. (Author/CCM)

  8. Effect of ionizing radiation on catalytic properties of Ca2+-ATP-ase from sarcoplasmic reticulum of skeletal muscle

    International Nuclear Information System (INIS)

    Bagel', I.M.; Shafranovskaya, E.V.; Gorokh, G.A.; Markova, A.G.

    1999-01-01

    It was studied kinetic and thermodynamic characteristics of Ca 2+ -ATP-ase of rat skeletal muscle (membranes of sarcoplasmic reticulum) after irradiation in doses 0,5, 4,0 and 8,0 Gy. It was shown that external gamma-irradiation at different doses changed kinetic and thermodynamic characteristics of the enzyme of sarcoplasmic reticulum membranes of skeletal muscle. These alterations probably correlate with disbalance of hormonal regulation of intracellular calcium metabolism and changes in membrane structure and functions

  9. Structural role of lipids in mitochondrial and sarcoplasmic reticulum membranes: freeze-fracture electron microscopy studies

    Energy Technology Data Exchange (ETDEWEB)

    Packer, L; Mehard, C W; Meissner, G; Zahler, W L; Fleischer, S

    1974-01-01

    The role of phospholipid in the structure of the membranes of beef heart mitochondria and of the sarcoplasmic reticulum membranes from rabbit skeletal muscle has been investigated by freeze-fracture electron microscopy. Progressive removal of membrane phospholipids, by phospholipase A treatment or detergent treatment, or by organic solvent extraction, results in loss of the smooth background seen in membrane fracture faces and decreased ability of membrane to undergo freeze fracture to yield fracture faces. Instead cross-sections of vesicles or particle clusters are observed. Sarcoplasmic reticulum vesicles have a 9 to 1 asymmetry in the distribution of particles between the convex and concave fracture faces. There is also a wide range of particle size distribution in both of these fracture faces with 85-A particles in greatest number. The removal of membrane associated proteins by detergent extraction does not appreciably change the distribution in particle size. Sarcoplasmic reticulum vesicles were dissolved with detergent and reassembled to form membrane vesicles containing mainly one protein (approx. 90%), i.e., the Ca/sup 2 +/ pump protein, and with a ratio of lipid to protein similar to the original membrane. The reconstituted vesicles readily underwent freeze fracture but the asymmetric particle distribution between the fracture faces was no longer observed. The size distribution of particles in the reconstituted membrane, consisting mainly of Ca/sup 2 +/ pump protein, and phospholipid, was similar in heterogeneity to the original sarcoplasmic reticulum membrane. Thus the heterogeneity in particle size could reflect variation in the orientation of the Ca/sup 2 +/ pump protein within the membrane.

  10. Different thermostabilities of sarcoplasmic reticulum (Ca2+ + Mg2+)-ATPases from rabbit and trout muscles.

    Science.gov (United States)

    de Toledo, F G; Albuquerque, M C; Goulart, B H; Chini, E N

    1995-05-01

    Trout and rabbit (Ca2+ + Mg2+)-ATPases from sarcoplasmic reticulum were compared for differences in thermal inactivation and susceptibility to trypsin digestion. The trout ATPase is more heat-sensitive than the rabbit ATPase and is stabilized by Ca2+, Na+, K+ and nucleotides. Solubilization of both ATPases shows that the two ATPases have different protein-intrinsic inactivation kinetics. When digested by trypsin, the two ATPases display different cleavage patterns. The present results indicate that the trout and rabbit ATPases have dissimilarities in protein structure that may explain the differences in thermal inactivation kinetics.

  11. The amino-terminal 200 amino acids of the plasma membrane Na+,K+-ATPase alpha subunit confer ouabain sensitivity on the sarcoplasmic reticulum Ca(2+)-ATPase.

    OpenAIRE

    Ishii, T; Takeyasu, K

    1993-01-01

    Cardiac glycosides such as G-strophanthin (ouabain) bind to and inhibit the plasma membrane Na+,K(+)-ATPase but not the sarcoplasmic reticulum (SR) Ca(2+)-ATPase, whereas thapsigargin specifically blocks the SR Ca(2+)-ATPase. The chimera [n/c]CC, in which the amino-terminal amino acids Met1 to Asp162 of the SR Ca(2+)-ATPase (SERCA1) were replaced with the corresponding portion of the Na+,K(+)-ATPase alpha 1 subunit (Met1 to Asp200), retained thapsigargin- and Ca(2+)-sensitive ATPase activity,...

  12. Investigation of function similarities between the sarcoplasmic reticulum and platelet calcium-dependent adenosinetriphosphatases with the inhibitors quercetin and calmidazolium

    International Nuclear Information System (INIS)

    Fischer, T.H.; Campbell, K.P.; White, G.C. II

    1987-01-01

    The platelet and skeletal sarcoplasmic reticulum calcium-dependent adenosinetriphosphatases (Ca 2+ -ATPases) were functionally compared with respect to substrate activation by steady-state kinetic methods using the inhibitors quercetin and calmidazolium. Quercetin inhibited platelet and sarcoplasmic reticulum Ca 2+ -ATPase activities in a dose-dependent manner with IC 50 values of 25 and 10 μM, respectively. Calmidazolium also inhibited platelet and sarcoplasmic reticulum Ca 2+ -ATPase activities, with half-maximal inhibition measured at 5 and 4 μM, respectively. Both inhibitors also affected the [ 45 Ca] calcium transport activity of intact platelet microsomes at concentrations similar to those which reduced Ca 2+ -ATPase activity. These inhibitors were then used to examine substrate ligation by the platelet and sarcoplasmic reticulum calcium pump proteins. For both Ca 2+ -ATPase proteins, quercetin has an affinity for the E-Ca 2 (fully ligated with respect to calcium at the exterior high-affinity calcium binding sites, unligated with respect to ATP) conformational state of the protein that is approximately 10-fold grater than for other conformational states in the hydrolytic cycle. Quercetin can thus be considered a competitive inhibitor of the calcium pump proteins with respect to ATP. In contrast to the effect of quercetin, calmidazolium interacts with the platelet and sarcoplasmic reticulum Ca 2+ -ATPases in an uncompetitive manner. The dissociation constants for this inhibitor for the different conformational states of the calcium pump proteins were similar, indicating that calmidazolium has equal affinity for all of the reaction intermediates probed. These observations indicate that the substrate ligation processes are similar for the two pump proteins. This supports the concept that the hydrolytic cycles of the two proteins are comparable

  13. Specific protein-protein interactions of calsequestrin with junctional sarcoplasmic reticulum of skeletal muscle

    International Nuclear Information System (INIS)

    Damiani, E.; Margreth, A.

    1990-01-01

    Minor protein components of triads and of sarcoplasmic reticulum (SR) terminal cisternae (TC), i.e. 47 and 37 kDa peptides and 31-30 kDa and 26-25 kDa peptide doublets, were identified from their ability to bind 125 I calsequestrin (CS) in the presence of EGTA. The CS-binding peptides are specifically associated with the junctional membrane of TC, since they could not be detected in junctional transverse tubules and in longitudinal SR fragments. The 31-30 kDa peptide doublet, exclusively, did not bind CS in the presence of Ca 2+ . Thus, different types of protein-protein interactions appear to be involved in selective binding of CS to junctional TC

  14. Vanilloid receptor expressed in the sarcoplasmic reticulum of rat skeletal muscle

    International Nuclear Information System (INIS)

    Xin Hong; Tanaka, Hideyuki; Yamaguchi, Maki; Takemori, Shigeru; Nakamura, Akio; Kohama, Kazuhiro

    2005-01-01

    Vanilloid receptor subtype 1 (VR1) was cloned as a capsaicin receptor from neuronal cells of dorsal root ganglia. VR1 was subsequently found in a few non-neuronal tissues, including skeletal muscle [Onozawa et al., Tissue distribution of capsaicin receptor in the various organs of rats, Proc. Jpn. Acad. Ser. B 76 (2000) 68-72]. We confirmed the expression of VR1 in muscle cells using the RT-PCR method and Western blot analysis. Immunostaining studies with a confocal microscope and an electron microscope indicated that VR1 was present in the sarcoplasmic reticulum (SR), a store of Ca 2+ . The SR releases Ca 2+ to cause a contraction when a muscle is excited. However, SR still releases a small amount of Ca 2+ under relaxed conditions. We found that this leakage was enhanced by capsaicin and was antagonized by capsazepine, a capsaicin blocker, indicating that leakage of Ca 2+ occurs through a channel composed of VR1

  15. Preparation of a highly concentrated, completely monomeric, active sarcoplasmic reticulum Ca2+-ATPase.

    Science.gov (United States)

    Lüdi, H; Hasselbach, W

    1985-11-21

    Sarcoplasmic reticulum vesicles from fast skeletal muscle were partially delipidated with sodium cholate at high ionic strength and sedimented in a discontinuous sucrose gradient. Phospholipid content was reduced from 0.777 mumol/mg protein to 0.242 mumol/mg protein. As judged from gel electrophoresis and high pressure liquid gel chromatography, accessory proteins were removed during centrifugation and the Ca2+-ATPase was obtained in an almost pure form. Addition of myristoylglycerophosphocholine (1 mg/mg protein) reactivates ATPase and dinitrophenylphosphatase activity to the same degree obtained with native vesicles. Using the analytical ultracentrifuge it could be demonstrated that the reactivated Ca2+-ATPase was present exclusively in a monomeric state. These results were obtained at high and low ionic strength and up to a protein concentration of 10 mg/ml. Therefore this preparation should be very useful to investigate differences between oligomeric and monomeric Ca2+-ATPase.

  16. Biochemical and morphological characterization of light and heavy sarcoplasmic reticulum vesicles. Volume I

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, Kevin Peter [Univ. of Rochester, NY (United States)

    1978-01-01

    Light (30 to 32.5% sucrose) and heavy (38.5 to 42% sucrose) sarcoplasmic reticulum vesicles (LSR, HSR) were isolated from rabbit leg muscle. They were then diluted and washed with sucrose or KCl and referred to as sucrose or KCl washed vesicles. Thin-section electron microscopy of LSR vesicles reveals empty vesicles of various sizes and shapes where as the HSR vesicles appear as rounded vesicles of uniform size filled with electron dense material. The LSR consists of predominantly Ca2+ + Mg2+ ATPase (80 to 90%), a small amount of the high affinity Ca binding protein (5%), and a 5000 dalton proteolipid. The sucrose HSR vesicles contain the Ca2+ + Mg2+ ATPase (50%), Calsequestrin (25%), high affinity Ca binding protein (5%), one extrinsic 34,000 dalton protein (3%), one intrinsic 30,000 dalton protein (3%), a 9000 dalton proteolipid, and a 5000 dalton proteolipid. The sucrose--washed HSR vesicles contain greater than three times the calcium content of the sucrose washed LSR vesicles where as the KCl--washed vesicles contain less than 15 nmoles Ca2+ mg of protein each. The light and heavy sarcoplasmic reticulum vesicles were both able to accumulate calcium in the presence of ATP. Exchange of methanesulfonate for chloride resulted in the release of calcium from both the light and heavy SR vesicles. Sucrose causes a slight inhibition of chloride--induced calcium release from the heavy SR vesicles but it greatly reduces the release of calcium from the light SR vesicles. Sodium dantrolene (20 uM) has no effect on the release of calcium from the light SR vesicles but it inhibits the release of calcium from the heavy SR vesicles. The results indicate that the chloride--induced release of calcium may be acting by two mechanisms, osmotic swelling and depolarization.

  17. Biochemical and morphological characterization of light and heavy sarcoplasmic reticulum vesicles. Volume I

    International Nuclear Information System (INIS)

    Campbell, K.P.

    1978-01-01

    Light (30 to 32.5% sucrose) and heavy (38.5 to 42% sucrose) sarcoplasmic reticulum vesicles (LSR, HSR) were isolated from rabbit leg muscle. They were then diluted and washed with sucrose or KCl and referred to as sucrose or KCl washed vesicles. Thin-section electron microscopy of LSR vesicles reveals empty vesicles of various sizes and shapes where as the HSR vesicles appear as rounded vesicles of uniform size filled with electron dense material. The LSR consists of predominantly Ca 2+ + Mg 2+ ATPase (80 to 90%), a small amount of the high affinity Ca binding protein (5%), and a 5000 dalton proteolipid. The sucrose HSR vesicles contain the Ca 2+ + Mg 2+ ATPase (50%), Calsequestrin (25%), high affinity Ca binding protein (5%), one extrinsic 34,000 dalton protein (3%), one intrinsic 30,000 dalton protein (3%), a 9000 dalton proteolipid, and a 5000 dalton proteolipid. The sucrose--washed HSR vesicles contain greater than three times the calcium content of the sucrose washed LSR vesicles where as the KCl--washed vesicles contain less than 15 nmoles Ca 2+ /mg of protein each. The light and heavy sarcoplasmic reticulum vesicles were both able to accumulate calcium in the presence of ATP. Exchange of methanesulfonate for chloride resulted in the release of calcium from both the light and heavy SR vesicles. Sucrose causes a slight inhibition of chloride--induced calcium release from the heavy SR vesicles but it greatly reduces the release of calcium from the light SR vesicles. Sodium dantrolene (20 uM) has no effect on the release of calcium from the light SR vesicles but it inhibits the release of calcium from the heavy SR vesicles. The results indicate that the chloride--induced release of calcium may be acting by two mechanisms, osmotic swelling and depolarization

  18. Effects of exercise training and exhaustion on 45Ca uptake by rat skeletal muscle mitochondria and sarcoplasmic reticulum

    International Nuclear Information System (INIS)

    Bonner, H.W.; Leslie, S.W.; Combs, A.B.; Tate, C.A.

    1976-01-01

    Mitochondrial and sarcoplasmic reticular 45 Ca 2+ uptake and Ca 2+ -ATPase activity were determined in skeletal muscle from exercise trained and non-trained rats at rest or following short-term exhaustive exercise. In trained rats exercised to exhaustion, mitochondrial 45 Ca 2+ uptake was significantly depressed when compared to non-trained rats at rest. Ca 2+ -ATPase activity of sarcoplasmic reticulum from trained rats exercised to exhaustion was significantly increased as compared to trained rats at rest. These data suggest that the disruptive influence of Ca 2+ accumulation in mitochondria isolated following exhaustive exercise may be diminished as a result of training

  19. Disturbances of the sarcoplasmic reticulum and transverse tubular system in 24-h electrostimulated fast-twitch skeletal muscle

    DEFF Research Database (Denmark)

    Frías, J A; Cadefau, J A; Prats, C

    2005-01-01

    Chronic low-frequency stimulation of rabbit tibialis anterior muscle over a 24-h period induces a conspicuous loss of isometric tension that is unrelated to muscle energy metabolism (J.A. Cadefau, J. Parra, R. Cusso, G. Heine, D. Pette, Responses of fatigable and fatigue-resistant fibres of rabbit...... muscle to low-frequency stimulation, Pflugers Arch. 424 (1993) 529-537). To assess the involvement of sarcoplasmic reticulum and transverse tubular system in this force impairment, we isolated microsomal fractions from stimulated and control (contralateral, unstimulated) muscles on discontinuous sucrose...... of muscles stimulated for 24 h underwent acute changes in the pattern of protein bands. First, light fractions from longitudinal sarcoplasmic reticulum, enriched in Ca2+-ATPase activity, R1 and R2, were greatly reduced (67% and 51%, respectively); this reduction was reflected in protein yield of crude...

  20. Biphasic decay of the Ca transient results from increased sarcoplasmic reticulum Ca leak

    Science.gov (United States)

    Sankaranarayanan, Rajiv; Li, Yatong; Greensmith, David J.; Eisner, David A.

    2016-01-01

    Key points Ca leak from the sarcoplasmic reticulum through the ryanodine receptor (RyR) reduces the amplitude of the Ca transient and slows its rate of decay.In the presence of β‐adrenergic stimulation, RyR‐mediated Ca leak produces a biphasic decay of the Ca transient with a fast early phase and a slow late phase.Two forms of Ca leak have been studied, Ca‐sensitising (induced by caffeine) and non‐sensitising (induced by ryanodine) and both induce biphasic decay of the Ca transient.Only Ca‐sensitising leak can be reversed by traditional RyR inhibitors such as tetracaine.Ca leak can also induce Ca waves. At low levels of leak, waves occur. As leak is increased, first biphasic decay and then slowed monophasic decay is seen. The level of leak has major effects on the shape of the Ca transient. Abstract In heart failure, a reduction in Ca transient amplitude and contractile dysfunction can by caused by Ca leak through the sarcoplasmic reticulum (SR) Ca channel (ryanodine receptor, RyR) and/or decreased activity of the SR Ca ATPase (SERCA). We have characterised the effects of two forms of Ca leak (Ca‐sensitising and non‐sensitising) on calcium cycling and compared with those of SERCA inhibition. We measured [Ca2+]i with fluo‐3 in voltage‐clamped rat ventricular myocytes. Increasing SR leak with either caffeine (to sensitise the RyR to Ca activation) or ryanodine (non‐sensitising) had similar effects to SERCA inhibition: decreased systolic [Ca2+]i, increased diastolic [Ca2+]i and slowed decay. However, in the presence of isoproterenol, leak produced a biphasic decay of the Ca transient in the majority of cells while SERCA inhibition produced monophasic decay. Tetracaine reversed the effects of caffeine but not of ryanodine. When caffeine (1 mmol l−1) was added to a cell which displayed Ca waves, the wave frequency initially increased before waves disappeared and biphasic decay developed. Eventually (at higher caffeine concentrations), the

  1. Molecular cloning and expression of cDNA encoding a lumenal calcium binding glycoprotein from sarcoplasmic reticulum

    International Nuclear Information System (INIS)

    Leberer, E.; Charuk, J.H.M.; MacLennan, D.H.; Green, N.M.

    1989-01-01

    Antibody screening was used to isolate a cDNA encoding the 160-kDa glycoprotein of rabbit skeletal muscle sarcoplasmic reticulum. The cDNA is identical to that encoding the 53-kDa glycoprotein except that it contains an in-frame insertion of 1,308 nucleotides near its 5' end, apparently resulting from alternative splicing. The protein encoded by the cDNA would contain a 19-residue NH 2 -terminal signal sequence and a 453-residue COOH-terminal sequence identical to the 53-kDa glycoprotein. It would also contain a 436-amino acid insert between these sequences. This insert would be highly acidic, suggesting that it might bind Ca 2+ . The purified 160-kDa glycoprotein and the glycoprotein expressed in COS-1 cells transfected with cDNA encoding the 160-kDa glycoprotein were shown to bind 45 C 2+ in a gel overlay assay. The protein was shown to be located in the lumen of the sarcoplasmic reticulum and to be associated through Ca 2+ with the membrane. The authors propose that this lumenal Ca 2+ binding glycoprotein of the sarcoplasmic reticulum be designated sarcalumenin

  2. Reduced sarcoplasmic reticulum content of releasable Ca2+ in rat soleus muscle fibres after eccentric contractions

    DEFF Research Database (Denmark)

    Nielsen, J S; Sahlin, K; Ørtenblad, N

    2007-01-01

    AIM: The purpose was to evaluate the effects of fatiguing eccentric contractions (EC) on calcium (Ca2+) handling properties in mammalian type I muscles. We hypothesized that EC reduces both endogenous sarcoplasmic reticulum (SR) content of releasable Ca2+ (eSRCa2+) and myofibrillar Ca2+ sensitivity....... METHODS: Isolated rat soleus muscles performed 30 EC bouts. Single fibres were isolated from the muscle and after mechanical removal of sarcolemma used to measure eSRCa2+, rate of SR Ca2+ loading and myofibrillar Ca2+ sensitivity. RESULTS: Following EC maximal force in whole muscle was reduced by 30......% and 16/100 Hz force ratio by 33%. The eSRCa2+ in fibres from non-stimulated muscles was 45 +/- 5% of the maximal loading capacity. After EC, eSRCa2+ per fibre CSA decreased by 38% (P = 0.05), and the maximal capacity of SR Ca2+ loading was depressed by 32%. There were no effects of EC on either...

  3. Impaired sarcoplasmic reticulum Ca(2+) release rate after fatiguing stimulation in rat skeletal muscle

    DEFF Research Database (Denmark)

    Ørtenblad, Niels; Sjøgaard, G; Madsen, Klavs

    2000-01-01

    during the first 0.5-1 h the metabolic state recovered to resting levels, and a slow phase from 1-3 h characterized by a rather slow recovery of the mechanical properties. The recovery of SR Ca(2+) release rate was closely correlated to +dF/dt during the slow phase of recovery (r(2) = 0.51; P ... to 66% that persisted for 1 h, followed by a gradual recovery to 87% of prefatigue release rate at 3 h recovery. Tetanic force and rate of force development (+dF/dt) and relaxation (-dF/dt) were depressed by approximately 80% after stimulation. Recovery occurred in two phases: an initial phase, in which......The purpose of the study was to characterize the sarcoplasmic reticulum (SR) function and contractile properties before and during recovery from fatigue in the rat extensor digitorum longus muscle. Fatiguing contractions (60 Hz, 150 ms/s for 4 min) induced a reduction of the SR Ca(2+) release rate...

  4. Hofmeister effect of anions on calcium translocation by sarcoplasmic reticulum Ca2+-ATPase

    Science.gov (United States)

    Tadini-Buoninsegni, Francesco; Moncelli, Maria Rosa; Peruzzi, Niccolò; Ninham, Barry W.; Dei, Luigi; Nostro, Pierandrea Lo

    2015-10-01

    The occurrence of Hofmeister (specific ion) effects in various membrane-related physiological processes is well documented. For example the effect of anions on the transport activity of the ion pump Na+, K+-ATPase has been investigated. Here we report on specific anion effects on the ATP-dependent Ca2+ translocation by the sarcoplasmic reticulum Ca2+-ATPase (SERCA). Current measurements following ATP concentration jumps on SERCA-containing vesicles adsorbed on solid supported membranes were carried out in the presence of different potassium salts. We found that monovalent anions strongly interfere with ATP-induced Ca2+ translocation by SERCA, according to their increasing chaotropicity in the Hofmeister series. On the contrary, a significant increase in Ca2+ translocation was observed in the presence of sulphate. We suggest that the anions can affect the conformational transition between the phosphorylated intermediates E1P and E2P of the SERCA cycle. In particular, the stabilization of the E1P conformation by chaotropic anions seems to be related to their adsorption at the enzyme/water and/or at the membrane/water interface, while the more kosmotropic species affect SERCA conformation and functionality by modifying the hydration layers of the enzyme.

  5. Interaction between neuronal nitric oxide synthase signaling and temperature influences sarcoplasmic reticulum calcium leak: role of nitroso-redox balance.

    Science.gov (United States)

    Dulce, Raul A; Mayo, Vera; Rangel, Erika B; Balkan, Wayne; Hare, Joshua M

    2015-01-02

    Although nitric oxide (NO) signaling modulates cardiac function and excitation-contraction coupling, opposing results because of inconsistent experimental conditions, particularly with respect to temperature, confound the ability to elucidate NO signaling pathways. Here, we show that temperature significantly modulates NO effects. To test the hypothesis that temperature profoundly affects nitroso-redox equilibrium, thereby affecting sarcoplasmic reticulum (SR) calcium (Ca(2+)) leak. We measured SR Ca(2+) leak in cardiomyocytes from wild-type (WT), NO/redox imbalance (neuronal nitric oxide synthase-deficient mice-1 [NOS1(-/-)]), and hyper S-nitrosoglutathione reductase-deficient (GSNOR(-/-)) mice. In WT cardiomyocytes, SR Ca(2+) leak increased because temperature decreased from 37°C to 23°C, whereas in NOS1(-/-) cells, the leak suddenly increased when the temperature surpassed 30°C. GSNOR(-/-) cardiomyocytes exhibited low leak throughout the temperature range. Exogenously added NO had a biphasic effect on NOS1(-/-) cardiomyocytes; reducing leak at 37°C but increasing it at subphysiological temperatures. Oxypurinol and Tempol diminished the leak in NOS1(-/-) cardiomyocytes. Cooling from 37°C to 23°C increased reactive oxygen species generation in WT but decreased it in NOS1(-/-) cardiomyocytes. Oxypurinol further reduced reactive oxygen species generation. At 23°C in WT cells, leak was decreased by tetrahydrobiopterin, an essential NOS cofactor. Cooling significantly increased SR Ca(2+) content in NOS1(-/-) cells but had no effect in WT or GSNOR(-/-). Ca(2+) leak and temperature are normally inversely proportional, whereas NOS1 deficiency reverses this effect, increasing leak and elevating reactive oxygen species production because temperature increases. Reduced denitrosylation (GSNOR deficiency) eliminates the temperature dependence of leak. Thus, temperature regulates the balance between NO and reactive oxygen species which in turn has a major effect on SR

  6. Dynamic measurement of the calcium buffering properties of the sarcoplasmic reticulum in mouse skeletal muscle.

    Science.gov (United States)

    Manno, Carlo; Sztretye, Monika; Figueroa, Lourdes; Allen, Paul D; Ríos, Eduardo

    2013-01-15

    The buffering power, B, of the sarcoplasmic reticulum (SR), ratio of the changes in total and free [Ca(2+)], was determined in fast-twitch mouse muscle cells subjected to depleting membrane depolarization. Changes in total SR [Ca(2+)] were measured integrating Ca(2+) release flux, determined with a cytosolic [Ca(2+)] monitor. Free [Ca(2+)](SR) was measured using the cameleon D4cpv-Casq1. In 34 wild-type (WT) cells average B during the depolarization (ON phase) was 157 (SEM 26), implying that of 157 ions released, 156 were bound inside the SR. B was significantly greater when BAPTA, which increases release flux, was present in the cytosol. B was greater early in the pulse - when flux was greatest - than at its end, and greater in the ON than in the OFF. In 29 Casq1-null cells, B was 40 (3.6). The difference suggests that 75% of the releasable calcium is normally bound to calsequestrin. In the nulls the difference in B between ON and OFF was less than in the WT but still significant. This difference and the associated decay in B during the ON were not artifacts of a slow SR monitor, as they were also found in the WT when [Ca(2+)](SR) was tracked with the fast dye fluo-5N. The calcium buffering power, binding capacity and non-linear binding properties of the SR measured here could be accounted for by calsequestrin at the concentration present in mammalian muscle, provided that its properties were substantially different from those found in solution. Its affinity should be higher, or K(D) lower than the conventionally accepted 1 mm; its cooperativity (n in a Hill fit) should be higher and the stoichiometry of binding should be at the higher end of the values derived in solution. The reduction in B during release might reflect changes in calsequestrin conformation upon calcium loss.

  7. pH-modulation of chloride channels from the sarcoplasmic reticulum of skeletal muscle.

    Science.gov (United States)

    Kourie, J I

    1999-01-01

    The understanding of the role of cytoplasmic pH in modulating sarcoplasmic reticulum (SR) ion channels involved in Ca2+ regulation is important for the understanding of the function of normal and adversely affected muscles. The dependency of the SR small chloride (SCl) channel from rabbit skeletal muscle on cytoplasmic pH (pHcis) and luminal pH (pHtrans) was investigated using the lipid bilayer-vesicle fusion technique. Low pHcis 6.75-4.28 modifies the operational mode of this multiconductance channel (conductance levels between 5 and 75 pS). At pHcis 7.26-7.37 the channel mode is dominated by the conductance and kinetics of the main conductance state (65-75 pS) whereas at low pHcis 6.75-4.28 the channel mode is dominated by the conductance and kinetics of subconductance states (5-40 pS). Similarly, low pHtrans 4.07, but not pHtrans 6.28, modified the activity of SCl channels. The effects of low pHcis are pronounced at 10(-3) and 10(-4) M [Ca2+]cis but are not apparent at 10(-5) M [Ca2+]cis, where the subconductances of the channel are already prominent. Low pHcis-induced mode shift in the SCl channel activity is due to modification of the channel proteins that cause the uncoupling of the subconductance states. The results in this study suggest that low pHcis can modify the functional properties of the skeletal SR ion channels and hence contribute, at least partly, to the malfunction in the contraction-relaxation mechanism in skeletal muscle under low cytoplasmic pH levels.

  8. Characterization of detergent-solubilized sarcoplasmic reticulum Ca2+-ATPase by high-performance liquid chromatography

    International Nuclear Information System (INIS)

    Andersen, J.P.; Vilsen, B.; Nielsen, H.; Moller, J.V.

    1986-01-01

    Sarcoplasmic reticulum Ca 2+ -ATPase solubilized by the nonionic detergent octaethylene glycol monododecyl ether was studied by molecular sieve high-performance liquid chromatography (HPLC) and analytical ultracentrifugation. Significant irreversible aggregation of soluble Ca 2+ -ATPase occurred within a few hours in the presence of ≤ 50 μM Ca 2+ . The aggregates were inactive and were primarily held together by hydrophobic forces. In the absence of reducing agent, secondary formation of disulfide bonds occurred. The stability of the inactive dimer upon dilution permitted unambiguous assignment of its elution position and sedimentation coefficient. At high 45 Ca 2+ concentration (500 μM), monomeric Ca 2+ -ATPase was stable for several house. Reversible self-association induced by variation in protein, detergent, and lipid concentrations was studied by large-zone HPLC. The association constant for dimerization of active Ca 2+ -ATPase was found to be 10 5 -10 6 M -1 depending on the detergent concentration. More detergent was bound to monomeric than to dimeric Ca 2+ -ATPase, even above the critical micellar concentration of the detergent. Binding of Ca 2+ and 48 V vanadate as well as ATP-dependent phosphorylation was studied in monomeric and in reversibly associated dimeric preparations. In both forms, two high-affinity Ca 2+ binding sites per phosphorylation site existed. The delipidated monomer purified by HPLC was able to form ADP-insensitive phosphoenzyme and to bind ATP and vanadate simultaneously. The results suggest that formation of Ca 2+ -ATPase oligomers in the membrane is governed by nonspecific forces (low affinity) and that each polypeptide chain constitutes a functional unit

  9. Patterns of proteolytic cleavage and carbodiimide derivatization in sarcoplasmic reticulum adenosinetriphosphatase

    International Nuclear Information System (INIS)

    de Ancos, J.G.; Inesi, G.

    1988-01-01

    Two series of experiments were carried out to characterize (a) peptide fragments of sarcoplasmic reticulum (SR) ATPase, based on proteolysis with different enzymes and distribution of known labels, and (b) specific labeling and functional inactivation patterns, following ATPase derivatization with dicyclohexylcarbodiimide (DCCD) under various conditions. Digestion with trypsin or chymotrypsin results in the initial cleavage of the SR ATPase in two fragments of similar size and then into smaller fragments, while subtilisin and thermolysin immediately yield smaller fragments. Peptide fragments were assigned to segments of the protein primary structure and to functionally relevant domains, such as those containing the 32 P at the active site and the fluorescein isothiocyanate at the nucleotide site. ATPase derivatization with [ 14 C]DCCD under mild conditions produced selective inhibition of ATPase hydrolytic catalysis without significant incorporation of the 14 C radioactive label. This effect is attributed to blockage of catalytically active residues by reaction of the initial DCCD adduct with endogenous or exogenous nucleophiles. ATPase derivatization with [ 14 C]DCCD under more drastic conditions produced inhibition of calcium binding, 14 C radioactive labeling of tryptic fragments A 1 and A 2 (but not of B), and extensive cross-linking. The presence of calcium during derivatization prevented functional inactivation, radioactive labeling of fragment A 2 , and internal cross-linking of fragment A 1 . It is proposed that both A 1 and A 2 fragments participate in formation of the calcium binding domain and that the labeled residues of fragment A 2 are directly involved in calcium complexation. A diagram is constructed, representing the relative positions of labels and functional domains within the ATPase protein

  10. Matching of sarcoplasmic reticulum and contractile properties in rat fast- and slow-twitch muscle fibres.

    Science.gov (United States)

    Trinh, Huong H; Lamb, Graham D

    2006-07-01

    1. The twitch characteristics (fast-twitch or slow-twitch) of skeletal muscle fibres are determined not only by the contractile apparatus properties of the fibre, but also by the time-course of Ca2+ release and re-uptake by the sarcoplasmic reticulum (SR). The present study examined, in individual fibres from non-transforming muscle of the rat, whether particular SR properties are matched to the contractile apparatus properties of the fibre, in particular in the case of fibres with fast-twitch contractile apparatus located in a slow-twitch muscle, namely the soleus. 2. Force was recorded in single, mechanically skinned fibres from extensor digitorum longus (EDL), gastrocnemius, peroneus longus and soleus muscles. Using repeated cycles in which the SR was emptied of all releasable Ca2+ and then reloaded, it was possible to determine the relative amount of Ca2+ present in the SR endogenously, the maximum SR capacity and the rate of Ca2+ loading. The sensitivity of the contractile apparatus to Ca2+ and Sr2+ was used to classify the fibres as fast-twitch (FT), slow-twitch (ST) or mixed (fibres examined) and thereby identify the likely troponin C and myosin heavy chain types present. 3. There was no significant difference in SR properties between the groups of FT fibres obtained from the four different muscles, including soleus. Despite some overlap in the SR properties of individual fibres between the FT and ST groups, the properties of the FT fibres in all four muscles studied were significantly different from those of the ST and mixed fibres. 4. In general, in FT fibres the SR had a larger capacity and the endogenous Ca2+ content was a relatively lower percentage of maximum compared with ST fibres. Importantly, in terms of their SR properties, FT fibres from soleus muscle more closely resembled FT fibres from other muscles than they did ST fibres from soleus muscle.

  11. Roles of phosphorylation and nucleotide binding domains in calcium transport by sarcoplasmic reticulum adenosinetriphosphatase

    International Nuclear Information System (INIS)

    Teruel, J.A.; Inesi, G.

    1988-01-01

    The roles of the phosphorylation (phosphorylated enzyme intermediate) and nucleotide binding domains in calcium transport were studied by comparing acetyl phosphate and ATP as substrates for the Ca 2+ -ATPase of sarcoplasmic reticulum vesicles. The authors found that the maximal level of phosphoenzyme obtained with either substrate is approximately 4 nmol/mg of protein, corresponding to the stoichiometry of catalytic sites in their preparation. The initial burst of phosphoenzyme formation observed in the transient state, following addition of either substrate, is accompanied by internalization of 2 mol of calcium per mole of phosphoenzyme. The internalized calcium is then translocated with a sequential pattern, independent of the substrate used. Following a rate-limiting step, the phosphoenzyme undergoes hydrolytic cleavage and proceeds to the steady-state activity which is soon back inhibited by the rise of Ca 2+ concentration in the lumen of the vesicles. When the back inhibition is released by the addition of oxalate, substrate utilization and calcium transport occur with a ratio of 1:2, independent of the substrate and its concentration. When the nucleotide binding site is derivatized with FITP, the enzyme can still utilize acetyl phosphate (but not ATP) for calcium transport. These observations demonstrate that the basic coupling mechanism of catalysis and calcium transport involves the phosphorylation and calcium binding domains, and not the nucleotide binding domain. On the other hand, occupancy of the FITC-sensitive nucleotide site is involved in kinetic regulation not only with respect to utilization of substrate for the phosphoryl transfer reaction but also for subsequent steps related to calcium translocation and phosphoenzyme turnover

  12. Inhibition of sarcoplasmic reticulum Ca(2+)-ATPase decreases atrioventricular node-paced heart rate in rabbits.

    Science.gov (United States)

    Cheng, Hongwei; Smith, Godfrey L; Orchard, Clive H; Hancox, Jules C; Burton, Francis L

    2012-10-01

    Recent data indicate that Ca(2+) cycling in isolated atrioventricular node (AVN) cells contributes to setting spontaneous rate. The aim of the present study was to extend this observation to the intact AVN in situ, by evaluating the effects of inhibiting sarcoplasmic reticulum Ca(2+) uptake with cyclopiazonic acid (CPA) on intact AVN spontaneous activity and its response to isoprenaline. A model of the AVN-paced heart was produced to investigate intact AVN automaticity, by surgical ablation of the sino-atrial node (SAN) in the rabbit Langendorff-perfused heart. Electrograms were recorded from a site close to the AVN (triangle of Koch), an atrial site above the AVN, the left atrium and right ventricle, enabling AVN pacing of the preparation to be confirmed. Before SAN ablation, the heart rate was 166.8 ± 5.4 beats min(-1). Ablation of the SAN was clearly indicated by a sudden and significant decrease of heart rate to 108.6 ± 9.6 beats min(-1) (P AVN rate to 187.8 ± 12.0 beats min(-1) after 1 min of application (P AVN rate to 81.6 ± 4.8 (n = 9) and 77.4 ± 6.0 beats min(-1) (n = 7), respectively [P AVN rate increase in response to isoprenaline from 78.8 ± 10.0 to 46.8 ± 6.8 and 26.7 ± 5.3%, respectively (P AVN rate and its response to isoprenaline indicate that Ca(2+) cycling is important to the intact AVN spontaneous activity and its acceleration during sympathetic stimulation.

  13. The influence of ionizing radiation on the structure of Ca-ATPase hydrophobic fragment of skeletal muscle sarcoplasmic reticulum

    International Nuclear Information System (INIS)

    Vojtsitskij, V.M.; Fedorov, A.N.; Lugovskoj, Eh.B.; Derzskaya, S.G.; Khizhnyak, S.V.; Kurskij, M.D.; Kucherenko, N.E.

    1990-01-01

    Early (1 and 24 h) after X-irradiation with a dose of 0.21 C/kg changes occurred in the acceptibility of the polypeptide chain parts of sarcoplasmic reticulum Ca-ATPase for the effect of trypsin. The analysis of the results of studying the structural and functional properties of a hydrophobic fragment of this enzyme in the control and after irradiation permitted to define the part of the Ca-ATPase polypeptide chain that provided ion selectivity of the fragment

  14. Activity of Ca(2+,Mg(2+-ATPase of sarcoplasmic reticulum and contraction strength of the frog skeletal muscles under the effect of organophosphorus insecticides

    Directory of Open Access Journals (Sweden)

    D. M. Nozdrenko

    2015-08-01

    Full Text Available The results of an experimental study of organo­phosphorus insecticides, including pirimiphosmethyl, diazinon and chlorpyrifos caused a decline of the contraction properties in m. tibialis anterior fiber bundles of Rana temporaria, as well as sarcoplasmic reticulum Ca2+,Mg2+-ATPase enzymatic activity reduction are outlined in this paper. Concentration-dependent strengths response diminishing in isolated skeletal muscle fiber bundles as a result of non-cholinergic influence of organophosphorus insecticides were found. A decrease of Ca2+,Mg2+-ATPase enzymatic activity in sarcoplasmic reticulum was observed after administration of each insecticide. The most significant inhibition of this enzyme was observed when using chlorpyrifos.

  15. [ACTIVITY OF Ca2+,Mg(2+)-ATPase OF SARCOPLASMIC RETICULUM AND CONTRACTION STRENGTH OF THE FROG SKELETAL MUSCLES UNDER THE EFFECT OF ORGANOPHOSPHORUS INSECTICIDES].

    Science.gov (United States)

    Nozdrenko, D M; Korchinska, L V; Soroca, V M

    2015-01-01

    The results of an experimental study of organophosphorus insecticides, including pirimiphosmethyl, diazinon and chlorpyrifos caused a decline of the contraction properties in m. tibialis anterior fiber bundles of Rana temporaria, as well as sarcoplasmic reticulum Ca2+, Mg(2+)-ATPase enzymatic activity reduction are outlined in this paper. Concentration-dependent strengths response diminishing in isolated skeletal muscle fiber bundles as a result of non-cholinergic influence of organophosphorus insecticides were found. A decrease of Ca2+, Mg(2+)-ATPase enzymatic activity in sarcoplasmic reticulum was observed after administration of each insecticide. The most significant inhibition of this enzyme was observed when using chlorpyrifos.

  16. Characterization of sarcoplasmic reticulum Ca(2+) ATPase pumps in muscle of patients with myotonic dystrophy and with hypothyroid myopathy.

    Science.gov (United States)

    Guglielmi, V; Oosterhof, A; Voermans, N C; Cardani, R; Molenaar, J P; van Kuppevelt, T H; Meola, G; van Engelen, B G; Tomelleri, G; Vattemi, G

    2016-06-01

    Sarcoplasmic/endoplasmic reticulum Ca(2+) ATPase (SERCA) pumps play the major role in lowering cytoplasmic calcium concentration in skeletal muscle by catalyzing the ATP-dependent transport of Ca(2+) from the cytosol to the lumen of the sarcoplasmic reticulum (SR). Although SERCA abnormalities have been hypothesized to contribute to the dysregulation of intracellular Ca(2+) homeostasis and signaling in muscle of patients with myotonic dystrophy (DM) and hypothyroid myopathy, the characterization of SERCA pumps remains elusive and their impairment is still unclear. We assessed the activity of SR Ca(2+)-ATPase, expression levels and fiber distribution of SERCA1 and SERCA2, and oligomerization of SERCA1 protein in muscle of patients with DM type 1 and 2, and with hypothyroid myopathy. Our data provide evidence that SR Ca(2+) ATPase activity, protein levels and muscle fiber distribution of total SERCA1 and SERCA2, and SERCA1 oligomerization pattern are similar in patients with both DM1 and DM2, hypothyroid myopathy and in control subjects. We prove that SERCA1b, the neonatal isoform of SERCA1, is expressed at protein level in muscle of patients with DM2 and, in lower amount, of patients with DM1. Our present study demonstrates that SERCA function is not altered in muscle of patients with DM and with hypothyroid myopathy. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Influence of the sarcoplasmic reticulum on the inotropic responses of the rat myocardium resulting from changes in rate and rhythm.

    Science.gov (United States)

    Mill, J G; Vassallo, D V; Leite, C M; Campagnaro, P

    1994-06-01

    1. The role of the sarcoplasmic reticulum (SR) in the inotropic responses produced by changes in stimulation rate and rhythm and resting tension was investigated in the rat myocardium. 2. Rat papillary muscles contracting isometrically (basic stimulation rate = 30/min) were superfused in vitro with normal Krebs solution and after addition of ryanodine (1 microM). Post-rest potentiation was obtained after pauses of 5, 10, 15, 30, 60 and 120 s, and the stimulation rate was changed from 6 to 90 bpm. Post-extrasystolic potentiation was induced by interpolating an extra stimulus after an interval of 413 +/- 15 ms. NiCl2 (2 mM) was used to confirm that contractions obtained after SR blockade with ryanodine were activated only by sarcolemmal calcium influx. 3. In the presence of ryanodine, the post-rest potentiation phenomenon disappears and the force-frequency relationship changes from the typical force decrease produced by rate increase to force increase. Under the effect of ryanodine, resting tension increased with the increase in stimulation rate. This behavior was enhanced by reducing extracellular KCl from 5.4 mM to 1 mM. This maneuver decreases Na(+)-K(+)-ATPase and increases intracellular Na+ activity, which reduces Ca2+ extrusion through the Na(+)-Ca2+ exchange mechanism. 4. SR participation in the post-extrasystolic potentiation phenomenon is also suggested because ryanodine treatment reversed the extrasystolic force depression into potentiation. In the presence of ryanodine, blockade of Ca2+ influx with NiCl2 (2 mM) abolished isometric contractions indicating that after SR blockade contractions are mainly dependent on sarcolemmal Ca2+ influx. 5. The results suggest that the SR is involved in the genesis of post-rest potentiation and contributes to the typical force-frequency relationship of the rat myocardium and to the post-extrasystolic potentiation phenomenon. Moreover, SR activity seems to be important for the maintenance of low resting tension in the

  18. Nandrolone decanoate treatment affects sarcoplasmic reticulum Ca(2+) ATPase function in skinned rat slow- and fast-twitch fibres.

    Science.gov (United States)

    Bouhlel, Aicha; Joumaa, Wissam H; Léoty, Claude

    2003-09-01

    The effects of anabolic-androgenic steroid administration on the function of the sarcoplasmic reticulum (SR) pump were investigated in chemically skinned fibres from the extensor digitorum longus (EDL) and soleus muscles of sedentary rats. Twenty male rats were divided into two groups, one group received an intramuscular injection of nandrolone decanoate (15 mg x kg(-1)) weekly for 8 weeks, the second received similar weekly doses of vehicle (sterile peanut oil). Compared with control muscles, nandrolone decanoate treatment reduced SR Ca(2+) loading in EDL and soleus fibres by 49% and 29%, respectively. In control and treated muscles, the rate of Ca(2+) leakage depended on the quantity of Ca(2+) loaded. Furthermore, for similar SR Ca(2+) contents, the Ca(2+) leakage rate was not significantly modified by nandrolone decanoate treatment. Nandrolone decanoate treatment thus affects Ca (2+) uptake by the SR in a fibre-type dependent manner.

  19. Temperature and Ca2+-dependence of the sarcoplasmic reticulum Ca2(+)-ATPase in haddock, salmon, rainbow trout and zebra cichlid

    DEFF Research Database (Denmark)

    Godiksen, Helene; Jessen, Flemming

    2002-01-01

    Temperature dependence of Ca2+-ATPase from the sarcoplasmic reticulum (SR) in rabbit muscle has been widely studied, and it is generally accepted that a break point in Arrhenius plot exist at approximately 20 degreesC. Whether the break point arises as a result of temperature dependent changes......+- ATPase activity. The temperature range of the plateau was 14-21 and 18-25 degreesC in salmon and rainbow trout, respectively. Ca2+-dependence in the four different fish species investigated was very similar with half maximal activation (K-0.5) between 0.2 and 0.6 muM and half maximal inhibition (I-0.......5) between 60 and 250 muM. Results indicated that interaction between SR Ca2+-ATPase and its lipid environment may play an important role for the different Arrhenius plot of the different types of fish species investigated. (C) 2002 Elsevier Science Inc. All rights reserved....

  20. A novel artificial microRNA expressing AAV vector for phospholamban silencing in cardiomyocytes improves Ca2+ uptake into the sarcoplasmic reticulum.

    Directory of Open Access Journals (Sweden)

    Tobias Gröβl

    Full Text Available In failing rat hearts, post-transcriptonal inhibition of phospholamban (PLB expression by AAV9 vector-mediated cardiac delivery of short hairpin RNAs directed against PLB (shPLBr improves both impaired SERCA2a controlled Ca2+ cycling and contractile dysfunction. Cardiac delivery of shPLB, however, was reported to cause cardiac toxicity in canines. Thus we developed a new AAV vector, scAAV6-amiR155-PLBr, expressing a novel engineered artificial microRNA (amiR155-PLBr directed against PLB under control of a heart-specific hybrid promoter. Its PLB silencing efficiency and safety were compared with those of an AAV vector expressing shPLBr (scAAV6-shPLBr from an ubiquitously active U6 promoter. Investigations were carried out in cultured neonatal rat cardiomyocytes (CM over a period of 14 days. Compared to shPLBr, amiR155-PLBr was expressed at a significantly lower level, resulting in delayed and less pronounced PLB silencing. Despite decreased knockdown efficiency of scAAV6-amiR155-PLBr, a similar increase of the SERCA2a-catalyzed Ca2+ uptake into sarcoplasmic reticulum (SR vesicles was observed for both the shPLBr and amiR155-PLBr vectors. Proteomic analysis confirmed PLB silencing of both therapeutic vectors and revealed that shPLBr, but not the amiR155-PLBr vector, increased the proinflammatory proteins STAT3, STAT1 and activated STAT1 phosphorylation at the key amino acid residue Tyr701. Quantitative RT-PCR analysis detected alterations in the expression of several cardiac microRNAs after treatment of CM with scAAV6-shPLBr and scAAV6-amiR155-PLBr, as well as after treatment with its related amiR155- and shRNAs-expressing control AAV vectors. The results demonstrate that scAAV6-amiR155-PLBr is capable of enhancing the Ca2+ transport function of the cardiac SR PLB/SERCA2a system as efficiently as scAAV6-shPLBr while offering a superior safety profile.

  1. 3-Bromopyruvate inhibits calcium uptake by sarcoplasmic reticulum vesicles but not SERCA ATP hydrolysis activity.

    Science.gov (United States)

    Jardim-Messeder, Douglas; Camacho-Pereira, Juliana; Galina, Antonio

    2012-05-01

    3-Bromopyruvate (3BrPA) is an antitumor agent that alkylates the thiol groups of enzymes and has been proposed as a treatment for neoplasias because of its specific reactivity with metabolic energy transducing enzymes in tumor cells. In this study, we show that the sarco/endoplasmic reticulum calcium (Ca(2+)) ATPase (SERCA) type 1 is one of the target enzymes of 3BrPA activity. Sarco/endoplasmic reticulum vesicles (SRV) were incubated in the presence of 1mM 3BrPA, which was unable to inhibit the ATPase activity of SERCA. However, Ca(2+)-uptake activity was significantly inhibited by 80% with 150 μM 3BrPA. These results indicate that 3BrPA has the ability to uncouple the ATP hydrolysis from the calcium transport activities. In addition, we observed that the inclusion of 2mM reduced glutathione (GSH) in the reaction medium with different 3BrPA concentrations promoted an increase in 40% in ATPase activity and protects the inhibition promoted by 3BrPA in calcium uptake activity. This derivatization is accompanied by a decrease of reduced cysteine (Cys), suggesting that GSH and 3BrPA increases SERCA activity and transport by pyruvylation and/or S-glutathiolation mediated by GSH at a critical Cys residues of the SERCA. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Role of sarcoplasmic reticulum calcium in development of secondary calcium rise and early afterdepolarizations in long QT syndrome rabbit model.

    Directory of Open Access Journals (Sweden)

    Po-Cheng Chang

    Full Text Available L-type calcium current reactivation plays an important role in development of early afterdepolarizations (EADs and torsades de pointes (TdP. Secondary intracellular calcium (Cai rise is associated with initiation of EADs.To test whether inhibition of sarcoplasmic reticulum (SR Ca2+ cycling suppresses secondary Cai rise and genesis of EADs.Langendorff perfusion and dual voltage and Cai optical mapping were conducted in 10 rabbit hearts. Atrioventricular block (AVB was created by radiofrequency ablation. After baseline studies, E4031, SR Ca2+ cycling inhibitors (ryanodine plus thapsigargin and nifedipine were then administrated subsequently, and the protocols were repeated.At baseline, there was no spontaneous or pacing-induced TdP. After E4031 administration, action potential duration (APD was significantly prolonged and the amplitude of secondary Cai rise was enhanced, and 7 (70% rabbits developed spontaneous or pacing-induced TdP. In the presence of ryanodine plus thapsigargin, TdP inducibility was significantly reduced (2 hearts, 20%, p = 0.03. Although APD was significantly prolonged (from 298 ± 30 ms to 457 ± 75 ms at pacing cycle length of 1000 m, p = 0.007 by ryanodine plus thapsigargin, the secondary Cai rise was suppressed (from 8.8 ± 2.6% to 1.2 ± 0.9%, p = 0.02. Nifedipine inhibited TdP inducibility in all rabbit hearts.In this AVB and long QT rabbit model, inhibition of SR Ca2+ cycyling reduces the inducibility of TdP. The mechanism might be suppression of secondary Cai rise and genesis of EADs.

  3. Effects of dantrolene and its derivatives on Ca2+ release from the sarcoplasmic reticulum of mouse skeletal muscle fibres

    Science.gov (United States)

    Ikemoto, Takaaki; Hosoya, Takamitsu; Aoyama, Hiroshi; Kihara, Yasutaka; Suzuki, Masaaki; Endo, Makoto

    2001-01-01

    We analysed the effect of dantrolene (Dan) and five newly synthesized derivatives (GIFs) on Ca2+ release from the sarcoplasmic reticulum (SR) of mouse skeletal muscle.In intact muscles, GIF-0185 reduced the size of twitch contraction induced by electrical stimulation to the same extent as Dan. GIF-0082, an azido-functionalized Dan derivative, also inhibited twitch contraction, although the extent of inhibition was less than that of Dan and of GIF-0185.In skinned fibres, Dan inhibited Ca2+-induced Ca2+ release (CICR) under Mg2+-free conditions at room temperature. In contrast, GIF-0082 and GIF-0185 showed no inhibitory effect on CICR under the same conditions.Dan-induced inhibition of CICR was not affected by the presence of GIF-0082, whereas it was diminished in the presence of GIF-0185.GIF-0082 and GIF-0185 significantly inhibited clofibric acid (Clof)-induced Ca2+ release, as did Dan.Several Dan derivatives other than GIF-0082 and GIF-0185 showed an inhibitory effect on twitch tension but not on the CICR mechanism. All of these derivatives inhibited Clof-induced Ca2+ release.The magnitudes of inhibition of Clof-induced Ca2+ release by all Dan derivatives were well correlated with those of twitch inhibition. This supports the notion that the mode of Clof-induced opening of the RyR-Ca2+ release channel may be similar to that of physiological Ca2+ release (PCR).These results indicate that the difference in opening modes of the RyR-Ca2+ release channel is recognized by certain Dan derivatives. PMID:11606312

  4. Properties of Ca2+ release induced by clofibric acid from the sarcoplasmic reticulum of mouse skeletal muscle fibres

    Science.gov (United States)

    Ikemoto, Takaaki; Endo, Makoto

    2001-01-01

    To characterize the effect of clofibric acid (Clof) on the Ca2+ release mechanism in the sarcoplasmic reticulum (SR) of skeletal muscle, we analysed the properties of Clof-induced Ca2+ release under various conditions using chemically skinned skeletal muscle fibres of the mouse.Clof (>0.5 mM) released Ca2+ from the SR under Ca2+-free conditions buffered with 10 mM EGTA (pCa >8).Co-application of ryanodine and Clof at pCa >8 but not ryanodine alone reduced the Ca2+ uptake capacity of the SR. Thus, Ca2+ release induced by Clof at pCa >8 must be a result of the activation of the ryanodine receptor (RyR).At pCa >8, (i) Clof-induced Ca2+ release was inhibited by adenosine monophosphate (AMP), (ii) the inhibitory effect of Mg2+ on the Clof-induced Ca2+ release was saturated at about 1 mM, and (iii) Clof-induced Ca2+ release was not inhibited by procaine (10 mM). These results indicate that Clof may activate the RyR-Ca2+ release channels in a manner different from Ca2+-induced Ca2+ release (CICR).In addition to this unique mode of opening, Clof also enhanced the CICR mode of opening of RyR-Ca2+ release channels.Apart from CICR, a high concentration of Ca2+ might also enhance the unique mode of opening by Clof.These results suggest that some features of Ca2+ release activated by Clof are similar to those of physiological Ca2+ release (PCR) in living muscle cells and raise the possibility that Clof may be useful in elucidating the mechanism of PCR in skeletal muscle. PMID:11606311

  5. Ryanodine receptor fragmentation and sarcoplasmic reticulum Ca2+ leak after one session of high-intensity interval exercise.

    Science.gov (United States)

    Place, Nicolas; Ivarsson, Niklas; Venckunas, Tomas; Neyroud, Daria; Brazaitis, Marius; Cheng, Arthur J; Ochala, Julien; Kamandulis, Sigitas; Girard, Sebastien; Volungevičius, Gintautas; Paužas, Henrikas; Mekideche, Abdelhafid; Kayser, Bengt; Martinez-Redondo, Vicente; Ruas, Jorge L; Bruton, Joseph; Truffert, Andre; Lanner, Johanna T; Skurvydas, Albertas; Westerblad, Håkan

    2015-12-15

    High-intensity interval training (HIIT) is a time-efficient way of improving physical performance in healthy subjects and in patients with common chronic diseases, but less so in elite endurance athletes. The mechanisms underlying the effectiveness of HIIT are uncertain. Here, recreationally active human subjects performed highly demanding HIIT consisting of 30-s bouts of all-out cycling with 4-min rest in between bouts (≤3 min total exercise time). Skeletal muscle biopsies taken 24 h after the HIIT exercise showed an extensive fragmentation of the sarcoplasmic reticulum (SR) Ca(2+) release channel, the ryanodine receptor type 1 (RyR1). The HIIT exercise also caused a prolonged force depression and triggered major changes in the expression of genes related to endurance exercise. Subsequent experiments on elite endurance athletes performing the same HIIT exercise showed no RyR1 fragmentation or prolonged changes in the expression of endurance-related genes. Finally, mechanistic experiments performed on isolated mouse muscles exposed to HIIT-mimicking stimulation showed reactive oxygen/nitrogen species (ROS)-dependent RyR1 fragmentation, calpain activation, increased SR Ca(2+) leak at rest, and depressed force production due to impaired SR Ca(2+) release upon stimulation. In conclusion, HIIT exercise induces a ROS-dependent RyR1 fragmentation in muscles of recreationally active subjects, and the resulting changes in muscle fiber Ca(2+)-handling trigger muscular adaptations. However, the same HIIT exercise does not cause RyR1 fragmentation in muscles of elite endurance athletes, which may explain why HIIT is less effective in this group.

  6. Ryanodine receptor fragmentation and sarcoplasmic reticulum Ca2+ leak after one session of high-intensity interval exercise

    Science.gov (United States)

    Place, Nicolas; Ivarsson, Niklas; Venckunas, Tomas; Neyroud, Daria; Brazaitis, Marius; Cheng, Arthur J.; Ochala, Julien; Kamandulis, Sigitas; Girard, Sebastien; Volungevičius, Gintautas; Paužas, Henrikas; Mekideche, Abdelhafid; Kayser, Bengt; Martinez-Redondo, Vicente; Bruton, Joseph; Truffert, Andre; Lanner, Johanna T.; Skurvydas, Albertas; Westerblad, Håkan

    2015-01-01

    High-intensity interval training (HIIT) is a time-efficient way of improving physical performance in healthy subjects and in patients with common chronic diseases, but less so in elite endurance athletes. The mechanisms underlying the effectiveness of HIIT are uncertain. Here, recreationally active human subjects performed highly demanding HIIT consisting of 30-s bouts of all-out cycling with 4-min rest in between bouts (≤3 min total exercise time). Skeletal muscle biopsies taken 24 h after the HIIT exercise showed an extensive fragmentation of the sarcoplasmic reticulum (SR) Ca2+ release channel, the ryanodine receptor type 1 (RyR1). The HIIT exercise also caused a prolonged force depression and triggered major changes in the expression of genes related to endurance exercise. Subsequent experiments on elite endurance athletes performing the same HIIT exercise showed no RyR1 fragmentation or prolonged changes in the expression of endurance-related genes. Finally, mechanistic experiments performed on isolated mouse muscles exposed to HIIT-mimicking stimulation showed reactive oxygen/nitrogen species (ROS)-dependent RyR1 fragmentation, calpain activation, increased SR Ca2+ leak at rest, and depressed force production due to impaired SR Ca2+ release upon stimulation. In conclusion, HIIT exercise induces a ROS-dependent RyR1 fragmentation in muscles of recreationally active subjects, and the resulting changes in muscle fiber Ca2+-handling trigger muscular adaptations. However, the same HIIT exercise does not cause RyR1 fragmentation in muscles of elite endurance athletes, which may explain why HIIT is less effective in this group. PMID:26575622

  7. The role of the sarcoplasmic reticulum in the generation of high heart rates and blood pressures in reptiles.

    Science.gov (United States)

    Galli, Gina L J; Gesser, Hans; Taylor, Edwin W; Shiels, Holly A; Wang, Tobias

    2006-05-01

    The functional significance of the sarcoplasmic reticulum (SR) in the generation of high heart rates and blood pressures was investigated in four species of reptile; the turtle, Trachemys scripta; the python, Python regius, the tegu lizard, Tupinanvis merianae, and the varanid lizard, Varanus exanthematicus. Force-frequency trials and imposed pauses were performed on ventricular and atrial tissue from each species with and without the SR inhibitor ryanodine, and in the absence and presence of adrenaline. In all species, an imposed pause of 1 or 5 min caused a post-rest decay of force, and a negative force-frequency response was observed in all species within their in vivo frequency range of heart rates. These relationships were not affected by either ryanodine or adrenaline. In ventricular strips from varanid lizards and pythons, ryanodine caused significant reductions in twitch force within their physiologically relevant frequency range. In atrial tissue from the tegu and varanid lizards, SR inhibition reduced twitch force across the whole of their physiological frequency range. In contrast, in the more sedentary species, the turtle and the python, SR inhibition only decreased twitch force at stimulation frequencies above maximal in vivo heart rates. Adrenaline caused an increase in twitch force in all species studied. In ventricular tissue, this positive inotropic effect was sufficient to overcome the negative effects of ryanodine. In atrial tissue however, adrenaline could only ameliorate the negative effects of ryanodine at the lower pacing frequencies. Our results indicate that reptiles recruit Ca2+ from the SR for force development in a frequency and tissue dependent manner. This is discussed in the context of the development of high reptilian heart rates and blood pressures.

  8. Impact of sarcoplasmic reticulum calcium release on calcium dynamics and action potential morphology in human atrial myocytes: a computational study.

    Directory of Open Access Journals (Sweden)

    Jussi T Koivumäki

    Full Text Available Electrophysiological studies of the human heart face the fundamental challenge that experimental data can be acquired only from patients with underlying heart disease. Regarding human atria, there exist sizable gaps in the understanding of the functional role of cellular Ca²+ dynamics, which differ crucially from that of ventricular cells, in the modulation of excitation-contraction coupling. Accordingly, the objective of this study was to develop a mathematical model of the human atrial myocyte that, in addition to the sarcolemmal (SL ion currents, accounts for the heterogeneity of intracellular Ca²+ dynamics emerging from a structurally detailed sarcoplasmic reticulum (SR. Based on the simulation results, our model convincingly reproduces the principal characteristics of Ca²+ dynamics: 1 the biphasic increment during the upstroke of the Ca²+ transient resulting from the delay between the peripheral and central SR Ca²+ release, and 2 the relative contribution of SL Ca²+ current and SR Ca²+ release to the Ca²+ transient. In line with experimental findings, the model also replicates the strong impact of intracellular Ca²+ dynamics on the shape of the action potential. The simulation results suggest that the peripheral SR Ca²+ release sites define the interface between Ca²+ and AP, whereas the central release sites are important for the fire-diffuse-fire propagation of Ca²+ diffusion. Furthermore, our analysis predicts that the modulation of the action potential duration due to increasing heart rate is largely mediated by changes in the intracellular Na+ concentration. Finally, the results indicate that the SR Ca²+ release is a strong modulator of AP duration and, consequently, myocyte refractoriness/excitability. We conclude that the developed model is robust and reproduces many fundamental aspects of the tight coupling between SL ion currents and intracellular Ca²+ signaling. Thus, the model provides a useful framework for future

  9. Sarcoplasmic reticulum calcium release compared in slow-twitch and fast-twitch fibres of mouse muscle.

    Science.gov (United States)

    Baylor, S M; Hollingworth, S

    2003-08-15

    Experiments were carried out to compare the amplitude and time course of Ca2+ release from the sarcoplasmic reticulum (SR) in intact slow-twitch and fast-twitch mouse fibres. Individual fibres within small bundles were injected with furaptra, a low-affinity, rapidly responding Ca2+ indicator. In response to a single action potential at 16 degrees C, the peak amplitude and half-duration of the change in myoplasmic free [Ca2+] (Delta[Ca2+]) differed significantly between fibre types (slow-twitch: peak amplitude, 9.4 +/- 1.0 microM (mean +/- S.E.M.); half-duration, 7.7 +/- 0.6 ms; fast-twitch: peak amplitude 18.5 +/- 0.5 microM; half-duration, 4.9 +/- 0.3 ms). SR Ca2+ release was estimated from Delta[Ca2+] with a computational model that calculated Ca2+ binding to the major myoplasmic Ca2+ buffers (troponin, ATP and parvalbumin); buffer concentrations and reaction rate constants were adjusted to reflect fibre-type differences. In response to an action potential, the total concentration of released Ca2+ (Delta[CaT]) and the peak rate of Ca2+ release ((d/dt)Delta[CaT]) differed about 3-fold between the fibre types (slow-twitch: Delta[CaT], 127 +/- 7 microM; (d/dt)Delta[CaT], 70 +/- 6 microM ms-1; fast-twitch: Delta[CaT], 346 +/- 6 microM; (d/dt)Delta[CaT], 212 +/- 4 microM ms-1). In contrast, the half-duration of (d/dt)Delta[CaT] was very similar in the two fibre types (slow-twitch, 1.8 +/- 0.1 ms; fast-twitch, 1.6 +/- 0.0 ms). When fibres were stimulated with a 5-shock train at 67 Hz, the peaks of (d/dt)Delta[CaT] in response to the second and subsequent shocks were much smaller than that due to the first shock; the later peaks, expressed as a fraction of the amplitude of the first peak, were similar in the two fibre types (slow-twitch, 0.2-0.3; fast-twitch, 0.1-0.3). The results support the conclusion that individual SR Ca2+ release units function similarly in slow-twitch and fast-twitch mammalian fibres.

  10. Size of the plasma membrane H+-ATPase from Neurospora crassa determined by radiation inactivation and comparison with the sarcoplasmic reticulum Ca2+-ATPase from skeletal muscle

    International Nuclear Information System (INIS)

    Bowman, B.J.; Berenski, C.J.; Jung, C.Y.

    1985-01-01

    Using radiation inactivation, the authors have measured the size of the H + -ATPase in Neurospora crassa plasma membranes. Membranes were exposed to either high energy electrons from a Van de Graaff generator or to gamma irradiation from 60 Co. Both forms of radiation caused an exponential loss of ATPase activity in parallel with the physical destruction of the Mr = 104,000 polypeptide of which this enzyme is composed. By applying target theory, the size of the H + -ATPase in situ was found to be approximately 2.3 X 10(5) daltons. They also used radiation inactivation to measure the size of the Ca 2+ -ATPase of sarcoplasmic reticulum and got a value of approximately 2.4 X 10(5) daltons, in agreement with previous reports. By irradiating a mixture of Neurospora plasma membranes and rabbit sarcoplasmic reticulum, they directly compared the sizes of these two ATPases and found them to be essentially the same. The authors conclude that both H + -ATPase and Ca 2+ -ATPase are oligomeric enzymes, most likely composed of two approximately 100,000-dalton polypeptides

  11. Uncoupling of sarcoplasmic reticulum Ca²⁺-ATPase by N-arachidonoyl dopamine. Members of the endocannabinoid family as thermogenic drugs

    DEFF Research Database (Denmark)

    Mahmmoud, Yasser Ahmed; Gaster, Michel

    2013-01-01

    BACKGROUND AND PURPOSE: The sarcoplasmic reticulum Ca²⁺-ATPase (SERCA) plays a role in thermogenesis. The exogenous compound capsaicin increased SERCA-mediated ATP hydrolysis not coupled to Ca²⁺ transport. Here, we have sought to identify endogenous compounds that may function as SERCA uncoupling...... agents. EXPERIMENTAL APPROACH: Using isolated SR vesicles from rabbits, we have screened for endogenous compounds that uncouple SERCA. We have also studied their ability to deplete cytoplasmic ATP from human skeletal muscle cells in culture. KEY RESULTS: Studies on SR vesicles showed that the endogenous......, regardless of the presence of glucose. CONCLUSIONS AND IMPLICATIONS: NADA is an endogenous molecule that may function as SERCA uncoupling agent in vivo. Members of the endocannabinoid family exert concerted actions on several Ca²⁺-handling proteins. Uncoupling of SERCA by exogenous compounds could be a novel...

  12. A low-dose β1-blocker in combination with milrinone improves intracellular Ca2+ handling in failing cardiomyocytes by inhibition of milrinone-induced diastolic Ca2+ leakage from the sarcoplasmic reticulum.

    Directory of Open Access Journals (Sweden)

    Shigeki Kobayashi

    Full Text Available OBJECTIVES: The purpose of this study was to investigate whether adding a low-dose β1-blocker to milrinone improves cardiac function in failing cardiomyocytes and the underlying cardioprotective mechanism. BACKGROUND: The molecular mechanism underlying how the combination of low-dose β1-blocker and milrinone affects intracellular Ca(2+ handling in heart failure remains unclear. METHODS: We investigated the effect of milrinone plus landiolol on intracellular Ca(2+ transient (CaT, cell shortening (CS, the frequency of diastolic Ca(2+ sparks (CaSF, and sarcoplasmic reticulum Ca(2+ concentration ({Ca(2+}SR in normal and failing canine cardiomyocytes and used immunoblotting to determine the phosphorylation level of ryanodine receptor (RyR2 and phospholamban (PLB. RESULTS: In failing cardiomyocytes, CaSF significantly increased, and peak CaT and CS markedly decreased compared with normal myocytes. Administration of milrinone alone slightly increased peak CaT and CS, while CaSF greatly increased with a slight increase in {Ca(2+}SR. Co-administration of β1-blocker landiolol to failing cardiomyocytes at a dose that does not inhibit cardiomyocyte function significantly decreased CaSF with a further increase in {Ca(2+}SR, and peak CaT and CS improved compared with milrinone alone. Landiolol suppressed the hyperphosphorylation of RyR2 (Ser2808 in failing cardiomyocytes but had no effect on levels of phosphorylated PLB (Ser16 and Thr17. Low-dose landiolol significantly inhibited the alternans of CaT and CS under a fixed pacing rate (0.5 Hz in failing cardiomyocytes. CONCLUSION: A low-dose β1-blocker in combination with milrinone improved cardiac function in failing cardiomyocytes, apparently by inhibiting the phosphorylation of RyR2, not PLB, and subsequent diastolic Ca(2+ leak.

  13. A low-dose β1-blocker in combination with milrinone improves intracellular Ca2+ handling in failing cardiomyocytes by inhibition of milrinone-induced diastolic Ca2+ leakage from the sarcoplasmic reticulum.

    Science.gov (United States)

    Kobayashi, Shigeki; Susa, Takehisa; Ishiguchi, Hironori; Myoren, Takeki; Murakami, Wakako; Kato, Takayoshi; Fukuda, Masakazu; Hino, Akihiro; Suetomi, Takeshi; Ono, Makoto; Uchinoumi, Hitoshi; Tateishi, Hiroki; Mochizuki, Mamoru; Oda, Tetsuro; Okuda, Shinichi; Doi, Masahiro; Yamamoto, Takeshi; Yano, Masafumi

    2015-01-01

    The purpose of this study was to investigate whether adding a low-dose β1-blocker to milrinone improves cardiac function in failing cardiomyocytes and the underlying cardioprotective mechanism. The molecular mechanism underlying how the combination of low-dose β1-blocker and milrinone affects intracellular Ca(2+) handling in heart failure remains unclear. We investigated the effect of milrinone plus landiolol on intracellular Ca(2+) transient (CaT), cell shortening (CS), the frequency of diastolic Ca(2+) sparks (CaSF), and sarcoplasmic reticulum Ca(2+) concentration ({Ca(2+)}SR) in normal and failing canine cardiomyocytes and used immunoblotting to determine the phosphorylation level of ryanodine receptor (RyR2) and phospholamban (PLB). In failing cardiomyocytes, CaSF significantly increased, and peak CaT and CS markedly decreased compared with normal myocytes. Administration of milrinone alone slightly increased peak CaT and CS, while CaSF greatly increased with a slight increase in {Ca(2+)}SR. Co-administration of β1-blocker landiolol to failing cardiomyocytes at a dose that does not inhibit cardiomyocyte function significantly decreased CaSF with a further increase in {Ca(2+)}SR, and peak CaT and CS improved compared with milrinone alone. Landiolol suppressed the hyperphosphorylation of RyR2 (Ser2808) in failing cardiomyocytes but had no effect on levels of phosphorylated PLB (Ser16 and Thr17). Low-dose landiolol significantly inhibited the alternans of CaT and CS under a fixed pacing rate (0.5 Hz) in failing cardiomyocytes. A low-dose β1-blocker in combination with milrinone improved cardiac function in failing cardiomyocytes, apparently by inhibiting the phosphorylation of RyR2, not PLB, and subsequent diastolic Ca(2+) leak.

  14. Interaction between endoplasmic/sarcoplasmic reticulum stress (ER/SR stress), mitochondrial signaling and Ca(2+) regulation in airway smooth muscle (ASM).

    Science.gov (United States)

    Delmotte, Philippe; Sieck, Gary C

    2015-02-01

    Airway inflammation is a key aspect of diseases such as asthma. Several inflammatory cytokines (e.g., TNFα and IL-13) increase cytosolic Ca(2+) ([Ca(2+)]cyt) responses to agonist stimulation and Ca(2+) sensitivity of force generation, thereby enhancing airway smooth muscle (ASM) contractility (hyper-reactive state). Inflammation also induces ASM proliferation and remodeling (synthetic state). In normal ASM, the transient elevation of [Ca(2+)]cyt induced by agonists leads to a transient increase in mitochondrial Ca(2+) ([Ca(2+)]mito) that may be important in matching ATP production with ATP consumption. In human ASM (hASM) exposed to TNFα and IL-13, the transient increase in [Ca(2+)]mito is blunted despite enhanced [Ca(2+)]cyt responses. We also found that TNFα and IL-13 induce reactive oxidant species (ROS) formation and endoplasmic/sarcoplasmic reticulum (ER/SR) stress (unfolded protein response) in hASM. ER/SR stress in hASM is associated with disruption of mitochondrial coupling with the ER/SR membrane, which relates to reduced mitofusin 2 (Mfn2) expression. Thus, in hASM it appears that TNFα and IL-13 result in ROS formation leading to ER/SR stress, reduced Mfn2 expression, disruption of mitochondrion-ER/SR coupling, decreased mitochondrial Ca(2+) buffering, mitochondrial fragmentation, and increased cell proliferation.

  15. Altered calcium pump and secondary deficiency of γ-sarcoglycan and microspan in sarcoplasmic reticulum membranes isolated from δ-sarcoglycan knockout mice

    Science.gov (United States)

    Solares-Pérez, Alhondra; Álvarez, Rocío; Crosbie, Rachelle H.; Vega-Moreno, Jesús; Medina-Monares, Joel; Estrada, Francisco J.; Ortega, Alicia; Coral-Vazquez, Ramón

    2016-01-01

    Sarcoglycans (SGs) and sarcospan (SSPN) are transmembrane proteins of the dystrophin-glycoprotein complex. Mutations in the genes encoding SGs cause many inherited forms of muscular dystrophy. In this study, using purified membranes of wild-type (WT) and δ-SG knockout (KO) mice, we found the specific localization of the SG-SSPN isoforms in transverse tubules (TT) and sarcoplasmic reticulum (SR) membranes. Immunoblotting revealed that the absence of δ-SG isoforms in TT and SR results in a secondary deficiency of γ-SG and µSPN. Our results showed augmented ATP hydrolytic activity, ATP-dependent calcium uptake and passive calcium efflux, probably through SERCA1 in KO compared to WT mice. Furthermore, we found a conformational change in SERCA1 isolated from KO muscle as demonstrated by calorimetric analysis. Following these alterations with mechanical properties, we found an increase in force in KO muscle with the same rate of fatigue but with a decreased fatigue recovery compared to WT. Together our observations suggest, for the first time, that the δ-SG isoforms may stabilize the expression of γ-SG and µSPN in the TT and SR membranes and that this possible complex may play a role in the maintenance of a stable level of resting cytosolic calcium concentration in skeletal muscle. PMID:20638123

  16. N-acetylcysteine fails to modulate the in vitro function of sarcoplasmic reticulum of diaphragm in the final phase of fatigue.

    Science.gov (United States)

    Mishima, T; Yamada, T; Matsunaga, S; Wada, M

    2005-07-01

    In the present study, we tested the hypothesis whether N-acetylcysteine (NAC), a non-specific antioxidant, might influence fatigue by modulating Ca2+-handling capacity by the sarcoplasmic reticulum (SR). In the presence (10 mm) or absence of NAC, bundles of rat diaphragm were stimulated with tetanic trains (350 ms, 30-40 Hz) at 1 train every 2 s for 300 s. SR functions, as assessed by SR Ca2+-uptake and release rates and SR Ca2+-ATPase activity, were measured in vitro on muscle homogenates. Following the 300-s stimulation, the force developed by NAC-treated muscles is approximately 1.8-fold higher (P depression in SR function (P < 0.05). Despite the differing degrees of fatigue between NAC-treated and non-treated muscles, SR functions in these muscles were reduced to similar extents. These results suggest that modulation of SR function measured in vitro may not be a major contributor to inhibition of diaphragmic fatigue with antioxidant, at least, in the final phase of fatigue where force output is remarkably reduced.

  17. The protein phosphatase-1/inhibitor-2 complex differentially regulates GSK3 dephosphorylation and increases sarcoplasmic/endoplasmic reticulum calcium ATPase 2 levels

    International Nuclear Information System (INIS)

    King, Taj D.; Gandy, Johanna C.; Bijur, Gautam N.

    2006-01-01

    The ubiquitously expressed protein glycogen synthase kinase-3 (GSK3) is constitutively active, however its activity is markedly diminished following phosphorylation of Ser21 of GSK3α and Ser9 of GSK3β. Although several kinases are known to phosphorylate Ser21/9 of GSK3, for example Akt, relatively much less is known about the mechanisms that cause the dephosphorylation of GSK3 at Ser21/9. In the present study KCl-induced plasma membrane depolarization of SH-SY5Y cells, which increases intracellular calcium concentrations caused a transient decrease in the phosphorylation of Akt at Thr308 and Ser473, and GSK3 at Ser21/9. Overexpression of the selective protein phosphatase-1 inhibitor protein, inhibitor-2, increased basal GSK3 phosphorylation at Ser21/9 and significantly blocked the KCl-induced dephosphorylation of GSK3β, but not GSK3α. The phosphorylation of Akt was not affected by the overexpression of inhibitor-2. GSK3 activity is known to affect sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA2) levels. Overexpression of inhibitor-2 or treatment of cells with the GSK3 inhibitors lithium and SB216763 increased the levels of SERCA2. These results indicate that the protein phosphatase-1/inhibitor-2 complex differentially regulates GSK3 dephosphorylation induced by KCl and that GSK3 activity regulates SERCA2 levels

  18. Determination of the separate lipid and protein profile structures derived from the total membrane profile structure or isolated sarcoplasmic reticulum via x-ray and neutron diffraction

    International Nuclear Information System (INIS)

    Herbette, L.; Blasie, J.K.

    1984-01-01

    Sarcoplasmic reticulum (SR) membranes were prepared to contain biosynthetically deuterated SR phospholipids utilizing specific and general phospholipid exchange proteins (PLEP). Functional measurements and freeze fracture on SR dispersions and x-ray diffraction of hydrated oriented membrane multilayers revealed that the exchanged SR membranes were very similar to unexchanged SR membranes. Low resolution (28-A) neutron diffraction studies utilizing SR membranes exchanged with either protonated or perdeuterated SR phospholipids allowed direct determination of the lipid profile within the isolated SR membrane at two different unit cell repeat distances. These lipid profile structures were found to be highly asymmetric regarding the conformation of the fatty acid chain extents and compositional distribution of phospholipid molecules in the inner vs. outer monolayer of the SR membrane bilayer. The relatively high resolution (11-A) electron-density profile from x-ray diffraction was decomposed by utilizing the asymmetry in the number of phospholipid molecules residing in the inner vs. outer monolayer of the SR lipid bilayer as obtained from the neutron diffraction study. To our knowledge, this represents the first direct determination of a lipid bilayer profile structure within an isolated membrane system

  19. Calsequestrin 2 deletion causes sinoatrial node dysfunction and atrial arrhythmias associated with altered sarcoplasmic reticulum calcium cycling and degenerative fibrosis within the mouse atrial pacemaker complex1

    Science.gov (United States)

    Glukhov, Alexey V.; Kalyanasundaram, Anuradha; Lou, Qing; Hage, Lori T.; Hansen, Brian J.; Belevych, Andriy E.; Mohler, Peter J.; Knollmann, Björn C.; Periasamy, Muthu; Györke, Sandor; Fedorov, Vadim V.

    2015-01-01

    Aims Loss-of-function mutations in Calsequestrin 2 (CASQ2) are associated with catecholaminergic polymorphic ventricular tachycardia (CPVT). CPVT patients also exhibit bradycardia and atrial arrhythmias for which the underlying mechanism remains unknown. We aimed to study the sinoatrial node (SAN) dysfunction due to loss of CASQ2. Methods and results In vivo electrocardiogram (ECG) monitoring, in vitro high-resolution optical mapping, confocal imaging of intracellular Ca2+ cycling, and 3D atrial immunohistology were performed in wild-type (WT) and Casq2 null (Casq2−/−) mice. Casq2−/− mice exhibited bradycardia, SAN conduction abnormalities, and beat-to-beat heart rate variability due to enhanced atrial ectopic activity both at baseline and with autonomic stimulation. Loss of CASQ2 increased fibrosis within the pacemaker complex, depressed primary SAN activity, and conduction, but enhanced atrial ectopic activity and atrial fibrillation (AF) associated with macro- and micro-reentry during autonomic stimulation. In SAN myocytes, CASQ2 deficiency induced perturbations in intracellular Ca2+ cycling, including abnormal Ca2+ release, periods of significantly elevated diastolic Ca2+ levels leading to pauses and unstable pacemaker rate. Importantly, Ca2+ cycling dysfunction occurred not only at the SAN cellular level but was also globally manifested as an increased delay between action potential (AP) and Ca2+ transient upstrokes throughout the atrial pacemaker complex. Conclusions Loss of CASQ2 causes abnormal sarcoplasmic reticulum Ca2+ release and selective interstitial fibrosis in the atrial pacemaker complex, which disrupt SAN pacemaking but enhance latent pacemaker activity, create conduction abnormalities and increase susceptibility to AF. These functional and extensive structural alterations could contribute to SAN dysfunction as well as AF in CPVT patients. PMID:24216388

  20. Calsequestrin content and SERCA determine normal and maximal Ca2+ storage levels in sarcoplasmic reticulum of fast- and slow-twitch fibres of rat.

    Science.gov (United States)

    Murphy, Robyn M; Larkins, Noni T; Mollica, Janelle P; Beard, Nicole A; Lamb, Graham D

    2009-01-15

    Whilst calsequestrin (CSQ) is widely recognized as the primary Ca2+ buffer in the sarcoplasmic reticulum (SR) in skeletal muscle fibres, its total buffering capacity and importance have come into question. This study quantified the absolute amount of CSQ isoform 1 (CSQ1, the primary isoform) present in rat extensor digitorum longus (EDL) and soleus fibres, and related this to their endogenous and maximal SR Ca2+ content. Using Western blotting, the entire constituents of minute samples of muscle homogenates or segments of individual muscle fibres were compared with known amounts of purified CSQ1. The fidelity of the analysis was proven by examining the relative signal intensity when mixing muscle samples and purified CSQ1. The CSQ1 contents of EDL fibres, almost exclusively type II fibres, and soleus type I fibres [SOL (I)] were, respectively, 36 +/- 2 and 10 +/- 1 micromol (l fibre volume)(-1), quantitatively accounting for the maximal SR Ca2+ content of each. Soleus type II [SOL (II)] fibres (approximately 20% of soleus fibres) had an intermediate amount of CSQ1. Every SOL (I) fibre examined also contained some CSQ isoform 2 (CSQ2), which was absent in every EDL and other type II fibre except for trace amounts in one case. Every EDL and other type II fibre had a high density of SERCA1, the fast-twitch muscle sarco(endo)plasmic reticulum Ca2+-ATPase isoform, whereas there was virtually no SERCA1 in any SOL (I) fibre. Maximal SR Ca2+ content measured in skinned fibres increased with CSQ1 content, and the ratio of endogenous to maximal Ca2+ content was inversely correlated with CSQ1 content. The relative SR Ca2+ content that could be maintained in resting cytoplasmic conditions was found to be much lower in EDL fibres than in SOL (I) fibres (approximately 20 versus >60%). Leakage of Ca2+ from the SR in EDL fibres could be substantially reduced with a SR Ca2+ pump blocker and increased by adding creatine to buffer cytoplasmic [ADP] at a higher level, both results

  1. Left ventricular wall stress and sarcoplasmic reticulum Ca(2+)-ATPase gene expression in renal hypertensive rats: dose-dependent effects of ACE inhibition and AT1-receptor blockade.

    Science.gov (United States)

    Zierhut, W; Studer, R; Laurent, D; Kästner, S; Allegrini, P; Whitebread, S; Cumin, F; Baum, H P; de Gasparo, M; Drexler, H

    1996-05-01

    Cardiac hypertrophy is associated with altered Ca2+ handling and may predispose to the development of LV dysfunction and cardiac failure. At the cellular level, the re-expression of ANF represents a well-established marker of myocyte hypertrophy while the decreased expression of the sarcoplasmatic reticulum (SR) Ca(2+)-ATPase is thought o play a crucial role in the alterations of Ca2+ handling and LV function. We assessed the dose-dependent effect of chronic ACE inhibition or AT1 receptor blockade on cardiac function in relation to the cardiac expression of the SR Ca(2+)-ATPase and ANF. Renal hypertensive rats (2K-1C) were treated for 12 weeks with three different doses of the ACE inhibitor benazepril, the AT1-receptor antagonist valsartan (each drug 0.3, 3, and 10 mg/kg per day i.p.) or placebo. LV dimensions, hypertrophy and wall stress were determined in vivo by magnetic resonance imaging and the gene expressions of ANF and SR Ca(2+)-ATPase were quantified by Northern blot. Low doses of both drugs did not affect blood pressure, hypertrophy, systolic wall stress and the ANF and SR Ca(2+)-ATPase gene expression. High doses of each drug reduced systolic blood pressure, wall stress, and LV hypertrophy to a similar extent and to values comparable to normotensive, age-matched rats. In addition, high dose treatment reduced LV end-systolic and end-diastolic volume as compared to untreated 2K-1C animals and normalized the mRNA levels of both ANF and SR Ca(2+)-ATPase (as compared to normotensive animals). We conclude that in this model, high doses of ACE inhibition and AT1-receptor blockade are necessary to normalize systolic blood pressure, LV hypertrophy and systolic LV wall stress which, in turn, is associated with restoration of a normal cardiac phenotype with respect to SR Ca(2+)-ATPase and ANF and normalization of cardiac function.

  2. Nanospan, an alternatively spliced isoform of sarcospan, localizes to the sarcoplasmic reticulum in skeletal muscle and is absent in limb girdle muscular dystrophy 2F.

    Science.gov (United States)

    Peter, Angela K; Miller, Gaynor; Capote, Joana; DiFranco, Marino; Solares-Pérez, Alhondra; Wang, Emily L; Heighway, Jim; Coral-Vázquez, Ramón M; Vergara, Julio; Crosbie-Watson, Rachelle H

    2017-06-06

    Sarcospan (SSPN) is a transmembrane protein that interacts with the sarcoglycans (SGs) to form a tight subcomplex within the dystrophin-glycoprotein complex that spans the sarcolemma and interacts with laminin in the extracellular matrix. Overexpression of SSPN ameliorates Duchenne muscular dystrophy in murine models. Standard cloning approaches were used to identify nanospan, and nanospan-specific polyclonal antibodies were generated and validated. Biochemical isolation of skeletal muscle membranes and two-photon laser scanning microscopy were used to analyze nanospan localization in muscle from multiple murine models. Duchenne muscular dystrophy biopsies were analyzed by immunoblot analysis of protein lysates as well as indirect immunofluorescence analysis of muscle cryosections. Nanospan is an alternatively spliced isoform of sarcospan. While SSPN has four transmembrane domains and is a core component of the sarcolemmal dystrophin-glycoprotein complex, nanospan is a type II transmembrane protein that does not associate with the dystrophin-glycoprotein complex. We demonstrate that nanospan is enriched in the sarcoplasmic reticulum (SR) fractions and is not present in the T-tubules. SR fractions contain membranes from three distinct structural regions: a region flanking the T-tubules (triadic SR), a SR region across the Z-line (ZSR), and a longitudinal SR region across the M-line (LSR). Analysis of isolated murine muscles reveals that nanospan is mostly associated with the ZSR and triadic SR, and only minimally with the LSR. Furthermore, nanospan is absent from the SR of δ-SG-null (Sgcd -/- ) skeletal muscle, a murine model for limb girdle muscular dystrophy 2F. Analysis of skeletal muscle biopsies from Duchenne muscular dystrophy patients reveals that nanospan is preferentially expressed in type I (slow) fibers in both control and Duchenne samples. Furthermore, nanospan is significantly reduced in Duchenne biopsies. Alternative splicing of proteins from the SG

  3. Effect of phospholipid, detergent and protein-protein interaction on stability and phosphoenzyme isomerization of soluble sarcoplasmic reticulum Ca-ATPase.

    Science.gov (United States)

    Vilsen, B; Andersen, J P

    1987-12-30

    The purpose of the present study was to elucidate the separate roles of lipid, detergent and protein-protein interaction for stability and catalytic properties of sarcoplasmic reticulum Ca-ATPase solubilized in the non-ionic detergent octa(ethylene glycol) monododecyl ether (C12E8). The use of large-zone high-performance liquid chromatography permitted us to define the self-association state of Ca-ATPase peptide at various detergent, phospholipid and protein concentrations, and also during enzymatic turnover with ATP. Conditions were established for monomerization of Ca-ATPase in the presence of a high concentration of phospholipid relative to detergent. The lipid-saturated monomeric preparation was relatively resistant to inactivation in the absence of Ca2+, whereas delipidated enzyme in monomeric or in oligomeric form was prone to inactivation. Kinetics of phosphoenzyme turnover were examined in the presence and absence of Mg2+. Dephosphorylation rates were sensitive to Mg2+, irrespective of whether the peptide was present in soluble monomeric form or was membrane-bound. C12E8-solubilized monomer without added phospholipid was, however, characterized by a fast initial phase of dephosphorylation in the absence of Mg2+. This was not observed with monomer saturated with phospholipid or with monomer solubilized in myristoylglycerophosphocholine or deoxycholate. The mechanism underlying this difference was shown to be a C12E8-induced acceleration of conversion of ADP-sensitive phosphoenzyme (E1P) to ADP-insensitive phosphoenzyme (E2P). The phosphoenzyme isomerization rate was also found to be enhanced by low-affinity binding of ATP. This was demonstrated both in membrane-bound and in soluble monomeric Ca-ATPase. Our results indicate that a single peptide chain constitutes the target for modulation of phosphoenzyme turnover by Mg2+ and ATP, and that detergent effects, distinct from those arising from disruption of protein-protein contacts, are the major determinants of

  4. Contractile properties and sarcoplasmic reticulum calcium content in type I and type II skeletal muscle fibres in active aged humans.

    Science.gov (United States)

    Lamboley, C R; Wyckelsma, V L; Dutka, T L; McKenna, M J; Murphy, R M; Lamb, G D

    2015-06-01

    Muscle weakness in old age is due in large part to an overall loss of skeletal muscle tissue, but it remains uncertain how much also stems from alterations in the properties of the individual muscle fibres. This study examined the contractile properties and amount of stored intracellular calcium in single muscle fibres of Old (70 ± 4 years) and Young (22 ± 3 years) adults. The maximum level of force production (per unit cross-sectional area) in fast twitch fibres in Old subjects was lower than in Young subjects, and the fibres were also less sensitive to activation by calcium. The amount of calcium stored inside muscle fibres and available to trigger contraction was also lower in both fast- and slow-twitch muscle fibres in the Old subjects. These findings indicate that muscle weakness in old age stems in part from an impaired capacity for force production in the individual muscle fibres. This study examined the contractile properties and sarcoplasmic reticulum (SR) Ca(2+) content in mechanically skinned vastus lateralis muscle fibres of Old (70 ± 4 years) and Young (22 ± 3 years) humans to investigate whether changes in muscle fibre properties contribute to muscle weakness in old age. In type II fibres of Old subjects, specific force was reduced by ∼17% and Ca(2+) sensitivity was also reduced (pCa50 decreased ∼0.05 pCa units) relative to that in Young. S-Glutathionylation of fast troponin I (TnIf ) markedly increased Ca(2+) sensitivity in type II fibres, but the increase was significantly smaller in Old versus Young (+0.136 and +0.164 pCa unit increases, respectively). Endogenous and maximal SR Ca(2+) content were significantly smaller in both type I and type II fibres in Old subjects. In fibres of Young, the SR could be nearly fully depleted of Ca(2+) by a combined caffeine and low Mg(2+) stimulus, whereas in fibres of Old the amount of non-releasable Ca(2+) was significantly increased (by > 12% of endogenous Ca(2+) content). Western

  5. Altered sarco(endo)plasmic reticulum calcium adenosine triphosphatase 2a content: Targets for heart failure therapy.

    Science.gov (United States)

    Liu, Gang; Li, Si Qi; Hu, Ping Ping; Tong, Xiao Yong

    2018-05-01

    Sarco(endo)plasmic reticulum calcium adenosine triphosphatase is responsible for transporting cytosolic calcium into the sarcoplasmic reticulum and endoplasmic reticulum to maintain calcium homeostasis. Sarco(endo)plasmic reticulum calcium adenosine triphosphatase is the dominant isoform expressed in cardiac tissue, which is regulated by endogenous protein inhibitors, post-translational modifications, hormones as well as microRNAs. Dysfunction of sarco(endo)plasmic reticulum calcium adenosine triphosphatase is associated with heart failure, which makes sarco(endo)plasmic reticulum calcium adenosine triphosphatase a promising target for heart failure therapy. This review summarizes current approaches to ameliorate sarco(endo)plasmic reticulum calcium adenosine triphosphatase function and focuses on phospholamban, an endogenous inhibitor of sarco(endo)plasmic reticulum calcium adenosine triphosphatase, pharmacological tools and gene therapies.

  6. Aerobic exercise training rescues cardiac protein quality control and blunts endoplasmic reticulum stress in heart failure rats.

    Science.gov (United States)

    Bozi, Luiz H M; Jannig, Paulo R; Rolim, Natale; Voltarelli, Vanessa A; Dourado, Paulo M M; Wisløff, Ulrik; Brum, Patricia C

    2016-11-01

    Cardiac endoplasmic reticulum (ER) stress through accumulation of misfolded proteins plays a pivotal role in cardiovascular diseases. In an attempt to reestablish ER homoeostasis, the unfolded protein response (UPR) is activated. However, if ER stress persists, sustained UPR activation leads to apoptosis. There is no available therapy for ER stress relief. Considering that aerobic exercise training (AET) attenuates oxidative stress, mitochondrial dysfunction and calcium imbalance, it may be a potential strategy to reestablish cardiac ER homoeostasis. We test the hypothesis that AET would attenuate impaired cardiac ER stress after myocardial infarction (MI). Wistar rats underwent to either MI or sham surgeries. Four weeks later, rats underwent to 8 weeks of moderate-intensity AET. Myocardial infarction rats displayed cardiac dysfunction and lung oedema, suggesting heart failure. Cardiac dysfunction in MI rats was paralleled by increased protein levels of UPR markers (GRP78, DERLIN-1 and CHOP), accumulation of misfolded and polyubiquitinated proteins, and reduced chymotrypsin-like proteasome activity. These results suggest an impaired cardiac protein quality control. Aerobic exercise training improved exercise capacity and cardiac function of MI animals. Interestingly, AET blunted MI-induced ER stress by reducing protein levels of UPR markers, and accumulation of both misfolded and polyubiquinated proteins, which was associated with restored proteasome activity. Taken together, our study provide evidence for AET attenuation of ER stress through the reestablishment of cardiac protein quality control, which contributes to better cardiac function in post-MI heart failure rats. These results reinforce the importance of AET as primary non-pharmacological therapy to cardiovascular disease. © 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  7. Overexpression of Sarcoendoplasmic Reticulum Calcium ATPase 2a Promotes Cardiac Sympathetic Neurotransmission via Abnormal Endoplasmic Reticulum and Mitochondria Ca2+ Regulation

    Science.gov (United States)

    Shanks, Julia; Herring, Neil; Johnson, Errin; Liu, Kun; Li, Dan

    2017-01-01

    Reduced cardiomyocyte excitation–contraction coupling and downregulation of the SERCA2a (sarcoendoplasmic reticulum calcium ATPase 2a) is associated with heart failure. This has led to viral transgene upregulation of SERCA2a in cardiomyocytes as a treatment. We hypothesized that SERCA2a gene therapy expressed under a similar promiscuous cytomegalovirus promoter could also affect the cardiac sympathetic neural axis and promote sympathoexcitation. Stellate neurons were isolated from 90 to 120 g male, Sprague–Dawley, Wistar Kyoto, and spontaneously hypertensive rats. Neurons were infected with Ad-mCherry or Ad-mCherry-hATP2Aa (SERCA2a). Intracellular Ca2+ changes were measured using fura-2AM in response to KCl, caffeine, thapsigargin, and carbonylcyanide-p-trifluoromethoxyphenylhydrazine to mobilize intracellular Ca2+ stores. The effect of SERCA2a on neurotransmitter release was measured using [3H]-norepinephrine overflow from 340 to 360 g Sprague–Dawley rat atria in response to right stellate ganglia stimulation. Upregulation of SERCA2a resulted in greater neurotransmitter release in response to stellate stimulation compared with control (empty: 98.7±20.5 cpm, n=7; SERCA: 186.5±28.41 cpm, n=8; Pneurons, SERCA2a overexpression facilitated greater depolarization-induced Ca2+ transients (empty: 0.64±0.03 au, n=57; SERCA: 0.75±0.03 au, n=68; Pneurons resulted in increased neurotransmission and increased Ca2+ loading into intracellular stores. Whether the increased Ca2+ transient and neurotransmission after SERCA2A overexpression contributes to enhanced sympathoexcitation in heart failure patients remains to be determined. PMID:28223472

  8. Redox regulation of calcium release in skeletal and cardiac muscle

    Directory of Open Access Journals (Sweden)

    CECILIA HIDALGO

    2002-01-01

    Full Text Available In skeletal and cardiac muscle cells, specific isoforms of the Ryanodine receptor channels mediate Ca2+ release from the sarcoplasmic reticulum. These channels are highly susceptible to redox modifications, which regulate channel activity. In this work, we studied the effects of Ca2+ (endogenous agonist and Mg2+ (endogenous inhibitor on the kinetics of Ca2+ release from sarcoplasmic reticulum vesicles isolated from skeletal or cardiac mammalian muscle. Native skeletal vesicles exhibited maximal stimulation of release kinetics by 10-20 µM [Ca2+], whereas in native cardiac vesicles, maximal stimulation of release required only 1 µM [Ca2+]. In 10 µM [Ca2+], free [Mg2+] < 0.1 mM produced marked inhibition of release from skeletal vesicles but free [Mg2+] ­ 0.8 mM did not affect release from cardiac vesicles. Incubation of skeletal or cardiac vesicles with the oxidant thimerosal increased their susceptibility to stimulation by Ca2+ and decreased the inhibitory effect of Mg2+ in skeletal vesicles. Sulfhydryl-reducing agents fully reversed the effects of thimerosal. The endogenous redox species, glutathione disulfide and S-nitrosoglutathione, also stimulated release from skeletal sarcoplasmic reticulum vesicles. In 10 µM [Ca2+], 35S-nitrosoglutathione labeled a protein fraction enriched in release channels through S-glutathiolation. Free [Mg2+] 1 mM or decreasing free [Ca2+] to the nM range prevented this reaction. Possible physiological and pathological consequences of redox modification of release channels on Ca2+ signaling in heart and muscle cells are discussed

  9. Cardiac Ablation of Rheb1 Induces Impaired Heart Growth, Endoplasmic Reticulum-Associated Apoptosis and Heart Failure in Infant Mice

    Science.gov (United States)

    Cao, Yunshan; Tao, Lichan; Shen, Shutong; Xiao, Junjie; Wu, Hang; Li, Beibei; Wu, Xiangqi; Luo, Wen; Xiao, Qi; Hu, Xiaoshan; Liu, Hailang; Nie, Junwei; Lu, Shuangshuang; Yuan, Baiyin; Han, Zhonglin; Xiao, Bo; Yang, Zhongzhou; Li, Xinli

    2013-01-01

    Ras homologue enriched in brain 1 (Rheb1) plays an important role in a variety of cellular processes. In this study, we investigate the role of Rheb1 in the post-natal heart. We found that deletion of the gene responsible for production of Rheb1 from cardiomyocytes of post-natal mice resulted in malignant arrhythmias, heart failure, and premature death of these mice. In addition, heart growth impairment, aberrant metabolism relative gene expression, and increased cardiomyocyte apoptosis were observed in Rheb1-knockout mice prior to the development of heart failure and arrhythmias. Also, protein kinase B (PKB/Akt) signaling was enhanced in Rheb1-knockout mice, and removal of phosphatase and tensin homolog (Pten) significantly prolonged the survival of Rheb1-knockouts. Furthermore, signaling via the mammalian target of rapamycin complex 1 (mTORC1) was abolished and C/EBP homologous protein (CHOP) and phosphorylation levels of c-Jun N-terminal kinase (JNK) were increased in Rheb1 mutant mice. In conclusion, this study demonstrates that Rheb1 is important for maintaining cardiac function in post-natal mice via regulation of mTORC1 activity and stress on the endoplasmic reticulum. Moreover, activation of Akt signaling helps to improve the survival of mice with advanced heart failure. Thus, this study provides direct evidence that Rheb1 performs multiple important functions in the heart of the post-natal mouse. Enhancing Akt activity improves the survival of infant mice with advanced heart failure. PMID:24351823

  10. Gene Therapy in Cardiac Arrhythmias

    Directory of Open Access Journals (Sweden)

    Praveen S.V

    2006-04-01

    Full Text Available Gene therapy has progressed from a dream to a bedside reality in quite a few human diseases. From its first application in adenosine deaminase deficiency, through the years, its application has evolved to vascular angiogenesis and cardiac arrhythmias. Gene based biological pacemakers using viral vectors or mesenchymal cells tested in animal models hold much promise. Induction of pacemaker activity within the left bundle branch can provide stable heart rates. Genetic modification of the AV node mimicking beta blockade can be therapeutic in the management of atrial fibrillation. G protein overexpression to modify the AV node also is experimental. Modification and expression of potassium channel genes altering the delayed rectifier potassium currents may permit better management of congenital long QT syndromes. Arrhythmias in a failing heart are due to abnormal calcium cycling. Potential targets for genetic modulation include the sarcoplasmic reticulum calcium pump, calsequestrin and sodium calcium exchanger.Lastly the ethical concerns need to be addressed.

  11. Cardiac Dysrhythmias and Neurological Dysregulation: Manifestations of Profound Hypomagnesemia

    Directory of Open Access Journals (Sweden)

    Sagger Mawri

    2017-01-01

    Full Text Available Magnesium is the second most common intracellular cation and serves as an important metabolic cofactor to over 300 enzymatic reactions throughout the human body. Among its various roles, magnesium modulates calcium entry and release from sarcoplasmic reticulum and regulates ATP pumps in myocytes and neurons, thereby regulating cardiac and neuronal excitability. Therefore, deficiency of this essential mineral may result in serious cardiovascular and neurologic derangements. In this case, we present the clinical course of a 76-year-old woman who presented with marked cardiac and neurological signs and symptoms which developed as a result of severe hypomagnesemia. The patient promptly responded to magnesium replacement once the diagnosis was established. We herein discuss the clinical presentation, pathophysiology, diagnosis, and management of severe hypomagnesemia and emphasize the implications of magnesium deficiency in the cardiovascular and central nervous systems. Furthermore, this case highlights the importance of having high vigilance for hypomagnesemia in the appropriate clinical setting.

  12. Monoamine oxidase-dependent endoplasmic reticulum-mitochondria dysfunction and mast cell degranulation lead to adverse cardiac remodeling in diabetes.

    Science.gov (United States)

    Deshwal, Soni; Forkink, Marleen; Hu, Chou-Hui; Buonincontri, Guido; Antonucci, Salvatore; Di Sante, Moises; Murphy, Michael P; Paolocci, Nazareno; Mochly-Rosen, Daria; Krieg, Thomas; Di Lisa, Fabio; Kaludercic, Nina

    2018-02-19

    Monoamine oxidase (MAO) inhibitors ameliorate contractile function in diabetic animals, but the mechanisms remain unknown. Equally elusive is the interplay between the cardiomyocyte alterations induced by hyperglycemia and the accompanying inflammation. Here we show that exposure of primary cardiomyocytes to high glucose and pro-inflammatory stimuli leads to MAO-dependent increase in reactive oxygen species that causes permeability transition pore opening and mitochondrial dysfunction. These events occur upstream of endoplasmic reticulum (ER) stress and are abolished by the MAO inhibitor pargyline, highlighting the role of these flavoenzymes in the ER/mitochondria cross-talk. In vivo, streptozotocin administration to mice induced oxidative changes and ER stress in the heart, events that were abolished by pargyline. Moreover, MAO inhibition prevented both mast cell degranulation and altered collagen deposition, thereby normalizing diastolic function. Taken together, these results elucidate the mechanisms underlying MAO-induced damage in diabetic cardiomyopathy and provide novel evidence for the role of MAOs in inflammation and inter-organelle communication. MAO inhibitors may be considered as a therapeutic option for diabetic complications as well as for other disorders in which mast cell degranulation is a dominant phenomenon.

  13. Ca2+-clock-dependent pacemaking in the sinus node is impaired in mice with a cardiac specific reduction in SERCA2 abundance

    Directory of Open Access Journals (Sweden)

    Sunil Jit Ramamoorthy Jeewanlal Logantha

    2016-06-01

    Full Text Available Background: The sarcoplasmic reticulum Ca2+-ATPase (SERCA2 pump is an important component of the Ca2+-clock pacemaker mechanism that provides robustness and flexibility to sinus node pacemaking. We have developed transgenic mice with reduced cardiac SERCA2 abundance (Serca2 KO as a model for investigating SERCA2’s role in sinus node pacemaking.Methods and Results: In Serca2 KO mice, ventricular SERCA2a protein content measured by Western blotting was 75% (P70% Serca2 downregulation.Conclusions: Serca2 KO mice show a disrupted Ca2+-clock-dependent pacemaker mechanism contributing to impaired sinus node and atrioventricular node function.

  14. Calcium release-dependent inactivation precedes formation of the tubular system in developing rat cardiac myocytes.

    Science.gov (United States)

    Macková, Katarina; Zahradníková, Alexandra; Hoťka, Matej; Hoffmannová, Barbora; Zahradník, Ivan; Zahradníková, Alexandra

    2017-12-01

    Developing cardiac myocytes undergo substantial structural and functional changes transforming the mechanism of excitation-contraction coupling from the embryonic form, based on calcium influx through sarcolemmal DHPR calcium channels, to the adult form, relying on local calcium release through RYR calcium channels of sarcoplasmic reticulum stimulated by calcium influx. We characterized day-by-day the postnatal development of the structure of sarcolemma, using techniques of confocal fluorescence microscopy, and the development of the calcium current, measured by the whole-cell patch-clamp in isolated rat ventricular myocytes. We characterized the appearance and expansion of the t-tubule system and compared it with the appearance and progress of the calcium current inactivation induced by the release of calcium ions from sarcoplasmic reticulum as structural and functional measures of direct DHPR-RYR interaction. The release-dependent inactivation of calcium current preceded the development of the t-tubular system by several days, indicating formation of the first DHPR-RYR couplons at the surface sarcolemma and their later spreading close to contractile myofibrils with the growing t-tubules. Large variability of both of the measured parameters among individual myocytes indicates uneven maturation of myocytes within the growing myocardium.

  15. The timing statistics of spontaneous calcium release in cardiac myocytes.

    Directory of Open Access Journals (Sweden)

    Mesfin Asfaw

    Full Text Available A variety of cardiac arrhythmias are initiated by a focal excitation that disrupts the regular beating of the heart. In some cases it is known that these excitations are due to calcium (Ca release from the sarcoplasmic reticulum (SR via propagating subcellular Ca waves. However, it is not understood what are the physiological factors that determine the timing of these excitations at both the subcellular and tissue level. In this paper we apply analytic and numerical approaches to determine the timing statistics of spontaneous Ca release (SCR in a simplified model of a cardiac myocyte. In particular, we compute the mean first passage time (MFPT to SCR, in the case where SCR is initiated by spontaneous Ca sparks, and demonstrate that this quantity exhibits either an algebraic or exponential dependence on system parameters. Based on this analysis we identify the necessary requirements so that SCR occurs on a time scale comparable to the cardiac cycle. Finally, we study how SCR is synchronized across many cells in cardiac tissue, and identify a quantitative measure that determines the relative timing of SCR in an ensemble of cells. Using this approach we identify the physiological conditions so that cell-to-cell variations in the timing of SCR is small compared to the typical duration of an SCR event. We argue further that under these conditions inward currents due to SCR can summate and generate arrhythmogenic triggered excitations in cardiac tissue.

  16. Deletion of Pr130 Interrupts Cardiac Development in Zebrafish

    Directory of Open Access Journals (Sweden)

    Jie Yang

    2016-11-01

    Full Text Available Protein phosphatase 2 regulatory subunit B, alpha (PPP2R3A, a regulatory subunit of protein phosphatase 2A (PP2A, is a major serine/threonine phosphatase that regulates crucial function in development and growth. Previous research has implied that PPP2R3A was involved in heart failure, and PR130, the largest transcription of PPP2R3A, functioning in the calcium release of sarcoplasmic reticulum (SR, plays an important role in the excitation-contraction (EC coupling. To obtain a better understanding of PR130 functions in myocardium and cardiac development, two pr130-deletion zebrafish lines were generated using clustered regularly interspaced short palindromic repeats (CRISPR/CRISPR-associated proteins (Cas system. Pr130-knockout zebrafish exhibited cardiac looping defects and decreased cardiac function (decreased fractional area and fractional shortening. Hematoxylin and eosin (H&E staining demonstrated reduced cardiomyocytes. Subsequent transmission electron microscopy revealed that the bright and dark bands were narrowed and blurred, the Z- and M-lines were fogged, and the gaps between longitudinal myocardial fibers were increased. Additionally, increased apoptosis was observed in cardiomyocyte in pr130-knockout zebrafish compared to wild-type (WT. Taken together, our results suggest that pr130 is required for normal myocardium formation and efficient cardiac contractile function.

  17. The role of mitochondria for the regulation of cardiac alternans

    Directory of Open Access Journals (Sweden)

    Stela M Florea

    2010-11-01

    Full Text Available Electromechanical and Ca alternans is a beat-to-beat alternation of action potential duration, contraction strength and Ca transient amplitude observed in cardiac myocytes at regular stimulation frequency. Ca alternans is a multifactorial process that is causally linked to cardiac arrhythmias. At the cellular level, conditions that increase fractional release from the sarcoplasmic reticulum or reduce diastolic Ca sequestration favor the occurrence of alternans. Mitochondria play a significant role in cardiac excitation-contraction coupling and Ca signaling by providing the energy for contraction and ATP-dependent processes and possibly by serving as Ca buffering organelles. Here we tested the hypothesis that impairment of mitochondrial function generates conditions that favor the occurrence of Ca alternans. Alternans were elicited by electrical pacing (>1 Hz in single cat atrial myocytes and intracellular Ca ([Ca]i was measured with the fluorescent Ca indicator Indo-1. The degree of alternans was quantified as the alternans ratio (AR=1-S/L, where S/L is the ratio of the small to the large amplitude of a pair of alternating Ca transients. Dissipation of mitochondrial membrane potential (with FCCP as well as inhibition of mitochondrial F1/F0-ATP synthase (oligomycin, electrontransport chain (rotenone, antimycin, CN-, Ca-dependent dehydrogenases and mitochondrial Ca uptake or extrusion, all enhanced AR and lowered the threshold for the occurrence of Ca alternans. The data indicate that impairment of mitochondrial function adversely affects cardiac Ca cycling leading to proarrhythmic Ca alternans.

  18. Endurance training in the spontaneously hypertensive rat: conversion of pathological into physiological cardiac hypertrophy.

    Science.gov (United States)

    Garciarena, Carolina D; Pinilla, Oscar A; Nolly, Mariela B; Laguens, Ruben P; Escudero, Eduardo M; Cingolani, Horacio E; Ennis, Irene L

    2009-04-01

    The effect of endurance training (swimming 90 min/d for 5 days a week for 60 days) on cardiac hypertrophy was investigated in the spontaneously hypertensive rat (SHR). Sedentary SHRs (SHR-Cs) and normotensive Wistar rats were used as controls. Exercise training enhanced myocardial hypertrophy assessed by left ventricular weight/tibial length (228+/-7 versus 251+/-5 mg/cm in SHR-Cs and exercised SHRs [SHR-Es], respectively). Myocyte cross-sectional area increased approximately 40%, collagen volume fraction decreased approximately 50%, and capillary density increased approximately 45% in SHR-Es compared with SHR-Cs. The mRNA abundance of atrial natriuretic factor and myosin light chain 2 was decreased by the swimming routine (100+/-19% versus 41+/-10% and 100+/-8% versus 61+/-9% for atrial natriuretic factor and myosin light chain 2 in SHR-Cs and SHR-Es, respectively). The expression of sarcoplasmic reticulum Ca(2+) pump was significantly augmented, whereas that of Na(+)/Ca(2+) exchanger was unchanged (93+/-7% versus 167+/-8% and 158+/-13% versus 157+/-7%, sarcoplasmic reticulum Ca(2+) pump and Na(+)/Ca(2+) exchanger in SHR-Cs and SHR-Es, respectively; PEndurance training inhibited apoptosis, as reflected by a decrease in caspase 3 activation and poly(ADP-ribose) polymerase-1 cleavage, and normalized calcineurin activity without inducing significant changes in the phosphatidylinositol 3-kinase/Akt pathway. The swimming routine improved midventricular shortening determined by echocardiography (32.4+/-0.9% versus 36.9+/-1.1% in SHR-Cs and SHR-Es, respectively; Pendurance training to convert pathological into physiological hypertrophy improving cardiac performance. The reduction of myocardial fibrosis and calcineurin activity plus the increase in capillary density represent factors to be considered in determining this beneficial effect.

  19. Regulation of basal and reserve cardiac pacemaker function by interactions of cAMP mediated PKA-dependent Ca2+ cycling with surface membrane channels

    Science.gov (United States)

    Vinogradova, Tatiana M.; Lakatta, Edward G.

    2009-01-01

    Decades of intensive research of primary cardiac pacemaker, the sinoatrial node, have established potential roles of specific membrane channels in the generation of the diastolic depolarization, the major mechanism allowing sinoatrial node cells generate spontaneous beating. During the last three decades, multiple studies made either in the isolated sinoatrial node or sinoatrial node cells have demonstrated a pivotal role of Ca2+ and, specifically Ca2+-release from sarcoplasmic reticulum, for spontaneous beating of cardiac pacemaker. Recently, spontaneous, rhythmic local subsarcolemmal Ca2+ releases from ryanodine receptors during late half of the diastolic depolarization have been implicated as a vital factor in the generation of sinoatrial node cells spontaneous firing. Local Ca2+ releases are driven by a unique combination of high basal cAMP production by adenylyl cyclases, high basal cAMP degradation by phosphodiesterases and a high level of cAMP-mediated PKA-dependent phosphorylation. These local Ca2+ releases activate an inward Na+-Ca2+ exchange current which accelerates the terminal diastolic depolarization rate and, thus, controls the spontaneous pacemaker firing. Both the basal primary pacemaker beating rate and its modulation via β-adrenergic receptor stimulation appear to be critically dependent upon intact RyR function and local subsarcolemmal sarcoplasmic reticulum generated Ca2+ releases. This review aspires to integrate the traditional viewpoint that has emphasized the supremacy of the ensemble of surface membrane ion channels in spontaneous firing of the primary cardiac pacemaker, and these novel perspectives of cAMP-mediated PKA-dependent Ca2+ cycling in regulation of the heart pacemaker clock, both in the basal state and during β-adrenergic receptor stimulation. PMID:19573534

  20. Hearts of dystonia musculorum mice display normal morphological and histological features but show signs of cardiac stress.

    Directory of Open Access Journals (Sweden)

    Justin G Boyer

    2010-03-01

    Full Text Available Dystonin is a giant cytoskeletal protein belonging to the plakin protein family and is believed to crosslink the major filament systems in contractile cells. Previous work has demonstrated skeletal muscle defects in dystonin-deficient dystonia musculorum (dt mice. In this study, we show that the dystonin muscle isoform is localized at the Z-disc, the H zone, the sarcolemma and intercalated discs in cardiac tissue. Based on this localization pattern, we tested whether dystonin-deficiency leads to structural defects in cardiac muscle. Desmin intermediate filament, microfilament, and microtubule subcellular organization appeared normal in dt hearts. Nevertheless, increased transcript levels of atrial natriuretic factor (ANF, 66% beta-myosin heavy chain (beta-MHC, 95% and decreased levels of sarcoplasmic reticulum calcium pump isoform 2A (SERCA2a, 26%, all signs of cardiac muscle stress, were noted in dt hearts. Hearts from two-week old dt mice were assessed for the presence of morphological and histological alterations. Heart to body weight ratios as well as left ventricular wall thickness and left chamber volume measurements were similar between dt and wild-type control mice. Hearts from dt mice also displayed no signs of fibrosis or calcification. Taken together, our data provide new insights into the intricate structure of the sarcomere by situating dystonin in cardiac muscle fibers and suggest that dystonin does not significantly influence the structural organization of cardiac muscle fibers during early postnatal development.

  1. Model of Ca(2+) Concentration Controlled by Sarcoplasmic Reticulum of Skeletal Muscle, Using the State Transition

    National Research Council Canada - National Science Library

    Yokota, M

    2001-01-01

    ...). This report proposed a model that represents Ca(2+) in a muscle cell controlled by the SR using a state transition probability model in which one state means that protein in the SR is binding ligands, and the other...

  2. Is the Ca2+-ATPase from sarcoplasmic reticulum also a heat pump?

    Science.gov (United States)

    Kjelstrup, Signe; de Meis, Leopoldo; Bedeaux, Dick; Simon, Jean-Marc

    2008-11-01

    We calculate, using the first law of thermodynamics, the membrane heat fluxes during active transport of Ca(2+) in the Ca(2+)-ATPase in leaky and intact vesicles, during ATP hydrolysis or synthesis conditions. The results show that the vesicle interior may cool down during hydrolysis and Ca(2+)-uptake, and heat up during ATP synthesis and Ca(2+)-efflux. The heat flux varies with the SERCA isoform. Electroneutral processes and rapid equilibration of water were assumed. The results are consistent with the second law of thermodynamics for the overall processes. The expression for the heat flux and experimental data, show that important contributions come from the enthalpy of hydrolysis for the medium in question, and from proton transport between the vesicle interior and exterior. The analysis give quantitative support to earlier proposals that certain, but not all, Ca(2+)-ATPases, not only act as Ca(2+)-pumps, but also as heat pumps. It can thus help explain why SERCA 1 type enzymes dominate in tissues where thermal regulation is important, while SERCA 2 type enzymes, with their lower activity and better ability to use the energy from the reaction to pump ions, dominate in tissues where this is not an issue.

  3. Direct measurement of newly synthesized ATP dissociation kinetics in sarcoplasmic reticulum ATPase

    International Nuclear Information System (INIS)

    Teruel-Puche, J.; Kurzmack, M.; Inesi, G.

    1987-01-01

    Incubation of SR vesicles with Ca 2+ and ( 32 P)acetylphosphate, yields steady state levels of ( 32 P)phosphorylated enzyme (ATPase) intermediate and high concentrations of Ca 2+ in the lumen of the vesicles. At this time, addition of ADP (and EGTA to lower the Ca 2+ concentration in the medium outside the vesicles) results in single cycle formation of (γ- 32 P)ATP by transfer of ( 32 P)phosphate from the enzyme intermediate to ADP. The phosphoenzyme decay and ATP formation exhibit a fast component within the first 20 msec following addition of ADP, and a slower component reaching an asymptote in approximately 100 msec. They have now measured by a rapid filtration method the fraction of newly synthesized ATP which is bound to the enzyme, as opposed to the fraction dissociated into the medium. They find that nearly all the ATP formed during the initial burst is still bound to the enzyme within the initial 20 msec of reaction. Dissociation of newly synthesized ATP occurs then with approximately 13 sec -1 rate constant, permitting reequilibration of the system and further formation of ATP. The rate limiting effect of ATP dissociation and other partial reactions on the slow component of single cycle ATP synthesis is evaluated by appropriate kinetic simulations

  4. Role of glycogen availability in sarcoplasmic reticulum Ca2+ kinetics in human skeletal muscle

    DEFF Research Database (Denmark)

    Ørtenblad, Niels; Nielsen, Joachim; Saltin, Bengt

    2011-01-01

    Glucose is stored as glycogen in skeletal muscle. The importance of glycogen as a fuel during exercise has been recognized since the 1960s; however, little is known about the precise mechanism that relates skeletal muscle glycogen to muscle fatigue. We show that low muscle glycogen is associated...... with an impairment of muscle ability to release Ca(2+), which is an important signal in the muscle activation. Thus, depletion of glycogen during prolonged, exhausting exercise may contribute to muscle fatigue by causing decreased Ca(2+) release inside the muscle. These data provide indications of a signal...

  5. PGC-1α accelerates cytosolic Ca2+ clearance without disturbing Ca2+ homeostasis in cardiac myocytes

    International Nuclear Information System (INIS)

    Chen, Min; Wang, Yanru; Qu, Aijuan

    2010-01-01

    Energy metabolism and Ca 2+ handling serve critical roles in cardiac physiology and pathophysiology. Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) is a multi-functional coactivator that is involved in the regulation of cardiac mitochondrial functional capacity and cellular energy metabolism. However, the regulation of PGC-1α in cardiac Ca 2+ signaling has not been fully elucidated. To address this issue, we combined confocal line-scan imaging with off-line imaging processing to characterize calcium signaling in cultured adult rat ventricular myocytes expressing PGC-1α via adenoviral transduction. Our data shows that overexpressing PGC-1α improved myocyte contractility without increasing the amplitude of Ca 2+ transients, suggesting that myofilament sensitivity to Ca 2+ increased. Interestingly, the decay kinetics of global Ca 2+ transients and Ca 2+ waves accelerated in PGC-1α-expressing cells, but the decay rate of caffeine-elicited Ca 2+ transients showed no significant change. This suggests that sarcoplasmic reticulum (SR) Ca 2+ -ATPase (SERCA2a), but not Na + /Ca 2+ exchange (NCX) contribute to PGC-1α-induced cytosolic Ca 2+ clearance. Furthermore, PGC-1α induced the expression of SERCA2a in cultured cardiac myocytes. Importantly, overexpressing PGC-1α did not disturb cardiac Ca 2+ homeostasis, because SR Ca 2+ load and the propensity for Ca 2+ waves remained unchanged. These data suggest that PGC-1α can ameliorate cardiac Ca 2+ cycling and improve cardiac work output in response to physiological stress. Unraveling the PGC-1α-calcium handing pathway sheds new light on the role of PGC-1α in the therapy of cardiac diseases.

  6. Heart rate variability alters cardiac repolarization and electromechanical dynamics.

    Science.gov (United States)

    Phadumdeo, Vrishti M; Weinberg, Seth H

    2018-04-07

    Heart rate continuously varies due to autonomic regulation, stochasticity in pacemaking, and circadian rhythm, collectively termed heart rate variability (HRV), during normal physiological conditions. Low HRV is clinically associated with an elevated risk of cardiac arrhythmias. Alternans, a beat-to-beat alternation in action potential duration (APD) and/or intracellular calcium (Ca) transient, is a well-known risk factor associated with cardiac arrhythmias that is typically studied under conditions of a constant pacing rate, i.e., the absence of HRV. In this study, we investigate the effects of HRV on the interplay between APD, Ca, and electromechanical properties, employing a nonlinear discrete-time map model that governs APD and intracellular Ca cycling with a stochastic pacing period. We find that HRV can decrease variation in APD and peak Ca at fast pacing rates for which alternans is present. Further, increased HRV typically disrupts the alternating pattern for both APD and peak Ca and weakens the correlation between APD and peak Ca, thus decoupling Ca-mediated instabilities from repolarization alternation. We find that the efficacy of these effects is regulated by the sarcoplasmic reticulum Ca uptake rate. Overall, these results demonstrate that HRV disrupts arrhythmogenic alternans and suggests that HRV may be a significant factor in preventing life-threatening arrhythmias. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. Action Potential Shortening and Impairment of Cardiac Function by Ablation of Slc26a6.

    Science.gov (United States)

    Sirish, Padmini; Ledford, Hannah A; Timofeyev, Valeriy; Thai, Phung N; Ren, Lu; Kim, Hyo Jeong; Park, Seojin; Lee, Jeong Han; Dai, Gu; Moshref, Maryam; Sihn, Choong-Ryoul; Chen, Wei Chun; Timofeyeva, Maria Valeryevna; Jian, Zhong; Shimkunas, Rafael; Izu, Leighton T; Chiamvimonvat, Nipavan; Chen-Izu, Ye; Yamoah, Ebenezer N; Zhang, Xiao-Dong

    2017-10-01

    Intracellular pH (pH i ) is critical to cardiac excitation and contraction; uncompensated changes in pH i impair cardiac function and trigger arrhythmia. Several ion transporters participate in cardiac pH i regulation. Our previous studies identified several isoforms of a solute carrier Slc26a6 to be highly expressed in cardiomyocytes. We show that Slc26a6 mediates electrogenic Cl - /HCO 3 - exchange activities in cardiomyocytes, suggesting the potential role of Slc26a6 in regulation of not only pH i , but also cardiac excitability. To test the mechanistic role of Slc26a6 in the heart, we took advantage of Slc26a6 knockout ( Slc26a6 -/ - ) mice using both in vivo and in vitro analyses. Consistent with our prediction of its electrogenic activities, ablation of Slc26a6 results in action potential shortening. There are reduced Ca 2+ transient and sarcoplasmic reticulum Ca 2+ load, together with decreased sarcomere shortening in Slc26a6 -/ - cardiomyocytes. These abnormalities translate into reduced fractional shortening and cardiac contractility at the in vivo level. Additionally, pH i is elevated in Slc26a6 -/ - cardiomyocytes with slower recovery kinetics from intracellular alkalization, consistent with the Cl - /HCO 3 - exchange activities of Slc26a6. Moreover, Slc26a6 -/ - mice show evidence of sinus bradycardia and fragmented QRS complex, supporting the critical role of Slc26a6 in cardiac conduction system. Our study provides mechanistic insights into Slc26a6, a unique cardiac electrogenic Cl - /HCO 3 - transporter in ventricular myocytes, linking the critical roles of Slc26a6 in regulation of pH i , excitability, and contractility. pH i is a critical regulator of other membrane and contractile proteins. Future studies are needed to investigate possible changes in these proteins in Slc26a6 -/ - mice. © 2017 American Heart Association, Inc.

  8. Cardiac Calcium ATPase Dimerization Measured by Cross-Linking and Fluorescence Energy Transfer.

    Science.gov (United States)

    Blackwell, Daniel J; Zak, Taylor J; Robia, Seth L

    2016-09-20

    The cardiac sarco/endoplasmic reticulum calcium ATPase (SERCA) establishes the intracellular calcium gradient across the sarcoplasmic reticulum membrane. It has been proposed that SERCA forms homooligomers that increase the catalytic rate of calcium transport. We investigated SERCA dimerization in rabbit left ventricular myocytes using a photoactivatable cross-linker. Western blotting of cross-linked SERCA revealed higher-molecular-weight species consistent with SERCA oligomerization. Fluorescence resonance energy transfer measurements in cells transiently transfected with fluorescently labeled SERCA2a revealed that SERCA readily forms homodimers. These dimers formed in the absence or presence of the SERCA regulatory partner, phospholamban (PLB) and were unaltered by PLB phosphorylation or changes in calcium or ATP. Fluorescence lifetime data are compatible with a model in which PLB interacts with a SERCA homodimer in a stoichiometry of 1:2. Together, these results suggest that SERCA forms constitutive homodimers in live cells and that dimer formation is not modulated by SERCA conformational poise, PLB binding, or PLB phosphorylation. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  9. Isoproterenol potentiation of methyl mercury effects in vivo cardiac ATPasees and 3H-dopamine uptake

    International Nuclear Information System (INIS)

    Ahammad-Sahib, K.I.; Moorthy, K.S.; Cameron, J.A.; Desaiah, D.

    1988-01-01

    Isoproterenol, a potent B-adrenergic receptor agonist, has been known to produce infarct-like myocardial lesions in rats characterized by swelling of endoplasmic reticulum. The swelling of this system is interpreted as an influx of large amount of extracellular fluid into myocardial cells by disturbances of the electrolyte metabolism. Isoproterenol is employed clinically as a bronchodilator in respiratory disorders and as a stimulant in heart block and cardiogenic shocks. In spite of its clinical use, possible drug-chemical interactions leading to adverse health effects are obvious when individuals on a regular isoproterenol treatment are exposed to an environmental contaminant such as methyl mercury. Consumption of fish and fish products is by far the most significant route of exposure to environmental mercury. In spite of such a possibility, little is know about isoproterenol-methyl mercury interaction. The present study forms the first of this kind to report such interactions and their effects on cardiac membrane bound enzymes such as Na + -K + and Ca 2+ -ATPases. Since Na + -K + ATPase has been implicated in uptake and release processes of catecholamines, the effects were also studied on 3 H-dopamine uptake by sarcoplasmic reticulum. As a prelude to these proposed long-term chronic studies with non-lethal doses in the present report only single and sub-lethal doses were used for a shorter (48h) duration

  10. PGC-1{alpha} accelerates cytosolic Ca{sup 2+} clearance without disturbing Ca{sup 2+} homeostasis in cardiac myocytes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Min, E-mail: chenminyx@gmail.com [Institute of Molecular Medicine, State Key Laboratory of Biomembrane and Membrane Biotechnology, Peking University, Beijing 100871 (China); Yunnan Centers for Diseases Prevention and Control, Kunming 650022 (China); Wang, Yanru [Institute of Molecular Medicine, State Key Laboratory of Biomembrane and Membrane Biotechnology, Peking University, Beijing 100871 (China); Qu, Aijuan [Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 (United States)

    2010-06-11

    Energy metabolism and Ca{sup 2+} handling serve critical roles in cardiac physiology and pathophysiology. Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1{alpha}) is a multi-functional coactivator that is involved in the regulation of cardiac mitochondrial functional capacity and cellular energy metabolism. However, the regulation of PGC-1{alpha} in cardiac Ca{sup 2+} signaling has not been fully elucidated. To address this issue, we combined confocal line-scan imaging with off-line imaging processing to characterize calcium signaling in cultured adult rat ventricular myocytes expressing PGC-1{alpha} via adenoviral transduction. Our data shows that overexpressing PGC-1{alpha} improved myocyte contractility without increasing the amplitude of Ca{sup 2+} transients, suggesting that myofilament sensitivity to Ca{sup 2+} increased. Interestingly, the decay kinetics of global Ca{sup 2+} transients and Ca{sup 2+} waves accelerated in PGC-1{alpha}-expressing cells, but the decay rate of caffeine-elicited Ca{sup 2+} transients showed no significant change. This suggests that sarcoplasmic reticulum (SR) Ca{sup 2+}-ATPase (SERCA2a), but not Na{sup +}/Ca{sup 2+} exchange (NCX) contribute to PGC-1{alpha}-induced cytosolic Ca{sup 2+} clearance. Furthermore, PGC-1{alpha} induced the expression of SERCA2a in cultured cardiac myocytes. Importantly, overexpressing PGC-1{alpha} did not disturb cardiac Ca{sup 2+} homeostasis, because SR Ca{sup 2+} load and the propensity for Ca{sup 2+} waves remained unchanged. These data suggest that PGC-1{alpha} can ameliorate cardiac Ca{sup 2+} cycling and improve cardiac work output in response to physiological stress. Unraveling the PGC-1{alpha}-calcium handing pathway sheds new light on the role of PGC-1{alpha} in the therapy of cardiac diseases.

  11. Intermittent cardiac overload results in adaptive hypertrophy and provides protection against left ventricular acute pressure overload insult.

    Science.gov (United States)

    Moreira-Gonçalves, Daniel; Henriques-Coelho, Tiago; Fonseca, Hélder; Ferreira, Rita; Padrão, Ana Isabel; Santa, Cátia; Vieira, Sara; Silva, Ana Filipa; Amado, Francisco; Leite-Moreira, Adelino; Duarte, José Alberto

    2015-09-01

    The present study aimed to test whether a chronic intermittent workload could induce an adaptive cardiac phenotype Chronic intermittent workload induced features of adaptive hypertrophy This was paralleled by protection against acute pressure overload insult The heart may adapt favourably to balanced demands, regardless of the nature of the stimuli. The present study aimed to test whether submitting the healthy heart to intermittent and tolerable amounts of workload, independently of its nature, could result in an adaptive cardiac phenotype. Male Wistar rats were subjected to treadmill running (Ex) (n = 20), intermittent cardiac overload with dobutamine (ITO) (2 mg kg(-1) , s.c.; n = 20) or placebo administration (Cont) (n = 20) for 5 days week(-1) for 8 weeks. Animals were then killed for histological and biochemical analysis or subjected to left ventricular haemodynamic evaluation under baseline conditions, in response to isovolumetric contractions and to sustained LV acute pressure overload (35% increase in peak systolic pressure maintained for 2 h). Baseline cardiac function was enhanced only in Ex, whereas the response to isovolumetric heartbeats was improved in both ITO and Ex. By contrast to the Cont group, in which rats developed diastolic dysfunction with sustained acute pressure overload, ITO and Ex showed increased tolerance to this stress test. Both ITO and Ex developed cardiomyocyte hypertrophy without fibrosis, no overexpression of osteopontin-1 or β-myosin heavy chain, and increased expression of sarcoplasmic reticulum Ca(2+) protein. Regarding hypertrophic pathways, ITO and Ex showed activation of the protein kinase B/mammalian target of rapamycin pathway but not calcineurin. Mitochondrial complex IV and V activities were also increased in ITO and Ex. Chronic submission to controlled intermittent cardiac overload, independently of its nature, results in an adaptive cardiac phenotype. Features of the cardiac overload, such as the duration and

  12. Functional Effects of Hyperthyroidism on Cardiac Papillary Muscle in Rats

    Directory of Open Access Journals (Sweden)

    Fabricio Furtado Vieira

    Full Text Available Abstract Background: Hyperthyroidism is currently recognized to affect the cardiovascular system, leading to a series of molecular and functional changes. However, little is known about the functional influence of hyperthyroidism in the regulation of cytoplasmic calcium and on the sodium/calcium exchanger (NCX in the cardiac muscle. Objectives: To evaluate the functional changes in papillary muscles isolated from animals with induced hyperthyroidism. Methods: We divided 36 Wistar rats into a group of controls and another of animals with hyperthyroidism induced by intraperitoneal T3 injection. We measured in the animals' papillary muscles the maximum contraction force, speed of contraction (+df/dt and relaxation (-df/dt, contraction and relaxation time, contraction force at different concentrations of extracellular sodium, post-rest potentiation (PRP, and contraction force induced by caffeine. Results: In hyperthyroid animals, we observed decreased PRP at all rest times (p < 0.05, increased +df/dt and -df/dt (p < 0.001, low positive inotropic response to decreased concentration of extracellular sodium (p < 0.001, reduction of the maximum force in caffeine-induced contraction (p < 0.003, and decreased total contraction time (p < 0.001. The maximal contraction force did not differ significantly between groups (p = 0.973. Conclusion: We hypothesize that the changes observed are likely due to a decrease in calcium content in the sarcoplasmic reticulum, caused by calcium leakage, decreased expression of NCX, and increased expression of a-MHC and SERCA2.

  13. Functional Effects of Hyperthyroidism on Cardiac Papillary Muscle in Rats.

    Science.gov (United States)

    Vieira, Fabricio Furtado; Olivoto, Robson Ruiz; Silva, Priscyla Oliveira da; Francisco, Julio Cesar; Fogaça, Rosalvo Tadeu Hochmuller

    2016-12-01

    Hyperthyroidism is currently recognized to affect the cardiovascular system, leading to a series of molecular and functional changes. However, little is known about the functional influence of hyperthyroidism in the regulation of cytoplasmic calcium and on the sodium/calcium exchanger (NCX) in the cardiac muscle. To evaluate the functional changes in papillary muscles isolated from animals with induced hyperthyroidism. We divided 36 Wistar rats into a group of controls and another of animals with hyperthyroidism induced by intraperitoneal T3 injection. We measured in the animals' papillary muscles the maximum contraction force, speed of contraction (+df/dt) and relaxation (-df/dt), contraction and relaxation time, contraction force at different concentrations of extracellular sodium, post-rest potentiation (PRP), and contraction force induced by caffeine. In hyperthyroid animals, we observed decreased PRP at all rest times (p < 0.05), increased +df/dt and -df/dt (p < 0.001), low positive inotropic response to decreased concentration of extracellular sodium (p < 0.001), reduction of the maximum force in caffeine-induced contraction (p < 0.003), and decreased total contraction time (p < 0.001). The maximal contraction force did not differ significantly between groups (p = 0.973). We hypothesize that the changes observed are likely due to a decrease in calcium content in the sarcoplasmic reticulum, caused by calcium leakage, decreased expression of NCX, and increased expression of a-MHC and SERCA2.

  14. Solution-blown nanofiber mats from fish sarcoplasmic protein

    DEFF Research Database (Denmark)

    Sett, S.; Boutrup Stephansen, Karen; Yarin, A.L.

    2016-01-01

    In the present work, solution-blowing was adopted to form nanofibers from fish sarcoplasmic proteins (FSPs). Nanofiber mats containing different weight ratios (up to 90/10) of FSP in the FSP/nylon 6 blended nanofibers were formed from formic acid solutions, and compared to electrospun fibers made...... that the production rate of solution-blowing was increased 30-fold in relation to electrospinning. Overall, this study reveals FSP as an interesting biopolymeric alternative to synthetic polymers, and the introduction of FSP to nylon 6 provides a composite with controlled properties....

  15. Serca2a and Na(+)/Ca(2+) exchanger are involved in left ventricular function following cardiac remodelling of female rats treated with anabolic androgenic steroid.

    Science.gov (United States)

    Nascimento, Andrews Marques do; Lima, Ewelyne Miranda de; Brasil, Girlandia Alexandre; Caliman, Izabela Facco; Silva, Josiane Fernandes da; Lemos, Virgínia Soares; Andrade, Tadeu Uggere de; Bissoli, Nazaré Souza

    2016-06-15

    Anabolic-androgenic steroids are misused, including by women, but little is known about the cardiovascular effects of these drugs on women. To evaluated the effects of nandrolone decanoate (ND) and resistive physical exercise on cardiac contractility in young female rats. Female Wistar rats were separated into 4 groups: C (untrained animals); E (animals were submitted to resistance exercise by jumping in water 5 times per week); ND (animals were treated with ND, 20mg/kg/week for 4weeks); and NDE (trained and treated). The haemodynamic parameters (+dP/dtmax, -dP/dtmin and Tau) were assessed in the left ventricle. The heart was collected for histological analyses and collagen deposition. The gastrocnemius muscle was weighed, and hypertrophy was assessed by the ratio of their weights to gastrocnemius/tibia length. The expression of calcium handling proteins was measured by western blot analysis. ND treatment and physical exercise increased cardiac contractility and relaxation. In addition, ND promoted increases in phospholamban phosphorylated (p-PLB) and isoforms of sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA2a) expression, while resistance exercise increased the phosphorylation of PLB and expression of Na(+)/Ca(2+) exchangers (NCX). Cardiac hypertrophy and collagen deposition were observed after ND treatment. Regulatory components of cytosolic calcium, such as SERCA2a and p-PLB, play important roles in modulating the contractility and relaxation effects of ND in females. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Preserved cardiac function despite marked impairment of cAMP generation.

    Directory of Open Access Journals (Sweden)

    Mei Hua Gao

    Full Text Available So many clinical trials of positive inotropes have failed, that it is now axiomatic that agents that increase cAMP are deleterious to the failing heart. An alternative strategy is to alter myocardial Ca(2+ handling or myofilament response to Ca(2+ using agents that do not affect cAMP. Although left ventricular (LV function is tightly linked to adenylyl cyclase (AC activity, the beneficial effects of AC may be independent of cAMP and instead stem from effects on Ca(2+ handling. Here we ask whether an AC mutant molecule that reduces LV cAMP production would have favorable effects on LV function through its effects on Ca(2+ handling alone.We generated transgenic mice with cardiac-directed expression of an AC6 mutant (AC6mut. Cardiac myocytes showed impaired cAMP production in response to isoproterenol (74% reduction; p<0.001, but LV size and function were normal. Isolated hearts showed preserved LV function in response to isoproterenol stimulation. AC6mut expression was associated with increased sarcoplasmic reticulum Ca(2+ uptake and the EC50 for SERCA2a activation was reduced. Cardiac myocytes isolated from AC6mut mice showed increased amplitude of Ca(2+ transients in response to isoproterenol (p = 0.0001. AC6mut expression also was associated with increased expression of LV S100A1 (p = 0.03 and reduced expression of phospholamban protein (p = 0.01.LV AC mutant expression is associated with normal cardiac function despite impaired cAMP generation. The mechanism appears to be through effects on Ca(2+ handling - effects that occur despite diminished cAMP.

  17. Association of cardiac myosin binding protein-C with the ryanodine receptor channel: putative retrograde regulation?

    Science.gov (United States)

    Stanczyk, Paulina J; Seidel, Monika; White, Judith; Viero, Cedric; George, Christopher H; Zissimopoulos, Spyros; Lai, F Anthony

    2018-06-21

    The cardiac muscle ryanodine receptor-Ca 2+ release channel (RyR2) constitutes the sarcoplasmic reticulum (SR) Ca 2+ efflux mechanism that initiates myocyte contraction, while cardiac myosin binding protein-C (cMyBP-C) mediates regulation of acto-myosin cross-bridge cycling. In this report, we provide the first evidence for the presence of direct interaction between these two proteins, forming a RyR2:cMyBP-C complex. The C-terminus of cMyBP-C binds with the RyR2 N-terminus in mammalian cells and is not mediated by a fibronectin-like domain. Notably, we detected complex formation between both recombinant cMyBP-C and RyR2, as well as with the native proteins in cardiac tissue. Cellular Ca 2+ dynamics in HEK293 cells is altered upon co-expression of cMyBP-C and RyR2, with lowered frequency of RyR2-mediated spontaneous Ca 2+ oscillations, suggesting cMyBP-C exerts a potential inhibitory effect on RyR2-dependent Ca 2+ release. Discovery of a functional RyR2 association with cMyBP-C provides direct evidence for a putative mechanistic link between cytosolic soluble cMyBP-C and SR-mediated Ca 2+ release, via RyR2. Importantly, this interaction may have clinical relevance to the observed cMyBP-C and RyR2 dysfunction in cardiac pathologies, such as hypertrophic cardiomyopathy. © 2018. Published by The Company of Biologists Ltd.

  18. Pitavastatin-attenuated cardiac dysfunction in mice with dilated cardiomyopathy via regulation of myocardial calcium handling proteins

    Directory of Open Access Journals (Sweden)

    Hu Wei

    2014-03-01

    Full Text Available C57BL/6 mice with dilated cardiomyopathy (DCM were randomly divided to receive placebo or pitavastatin at a dose of 1 or 3 mg kg-1d-1. After 8 weeks treatment, mice with dilated cardiomyopathy developed serious cardiac dysfunction characterized by significantly enhanced left ventricular end-diastolic diameter (LVIDd, decreased left ventricular ejection fraction (LVEF as well as left ventricular short axis fractional shortening (LVFS, accompanied with enlarged cardiomyocytes, and increased plasma levels of N-terminal pro-B type natriuretic peptide (NT-proBNP and plasma angiotensin II (AngII concentration. Moreover, myocardium sarcoplasmic reticulum Ca2+ pump (SERCA-2 activity was decreased. The ratio of phosphorylated phospholamban (PLB to total PLB decreased significantly with the down-regulation of SERCA- -2a and ryanodine receptor (RyR2 expression. Pitavastatin was found to ameliorate the cardiac dysfunction in mice with dilated cardiomyopathy by reversing the changes in the ratios of phosphorylated PLB to total PLB, SERCA-2a and RyR2 via reducing the plasma AngII concentration and the expressions of myocardium angiotensin II type 1 receptor (AT1R and protein kinase C (PKCb2. The possible underlying mechanism might be the regulation of myocardial AT1R-PKCb2-Ca2+ handling proteins.

  19. Cannabinoid signalling inhibits sarcoplasmic Ca2+ release and regulates excitation–contraction coupling in mammalian skeletal muscle

    Science.gov (United States)

    Oláh, Tamás; Bodnár, Dóra; Tóth, Adrienn; Vincze, János; Fodor, János; Reischl, Barbara; Kovács, Adrienn; Ruzsnavszky, Olga; Dienes, Beatrix; Szentesi, Péter; Friedrich, Oliver

    2016-01-01

    Key points Marijuana was found to cause muscle weakness, although the exact regulatory role of its receptors (CB1 cannabinoid receptor; CB1R) in the excitation–contraction coupling (ECC) of mammalian skeletal muscle remains unknown.We found that CB1R activation or its knockout did not affect muscle force directly, whereas its activation decreased the Ca2+‐sensitivity of the contractile apparatus and made the muscle fibres more prone to fatigue.We demonstrate that CB1Rs are not connected to the inositol 1,4,5‐trisphosphate pathway either in myotubes or in adult muscle fibres.By contrast, CB1Rs constitutively inhibit sarcoplasmic Ca2+ release and sarcoplasmic reticulum Ca2+ ATPase during ECC in a Gi/o protein‐mediated way in adult skeletal muscle fibres but not in myotubes.These results help with our understanding of the physiological effects and pathological consequences of CB1R activation in skeletal muscle and may be useful in the development of new cannabinoid drugs. Abstract Marijuana was found to cause muscle weakness, although it is unknown whether it affects the muscles directly or modulates only the motor control of the central nervous system. Although the presence of CB1 cannabinoid receptors (CB1R), which are responsible for the psychoactive effects of the drug in the brain, have recently been demonstrated in skeletal muscle, it is unclear how CB1R‐mediated signalling affects the contraction and Ca²⁺ homeostasis of mammalian skeletal muscle. In the present study, we demonstrate that in vitro CB1R activation increased muscle fatigability and decreased the Ca2+‐sensitivity of the contractile apparatus, whereas it did not alter the amplitude of single twitch contractions. In myotubes, CB1R agonists neither evoked, nor influenced inositol 1,4,5‐trisphosphate (IP3)‐mediated Ca2+ transients, nor did they alter excitation–contraction coupling. By contrast, in isolated muscle fibres of wild‐type mice, although CB1R agonists did not evoke IP3

  20. Cannabinoid signalling inhibits sarcoplasmic Ca2+ release and regulates excitation-contraction coupling in mammalian skeletal muscle.

    Science.gov (United States)

    Oláh, Tamás; Bodnár, Dóra; Tóth, Adrienn; Vincze, János; Fodor, János; Reischl, Barbara; Kovács, Adrienn; Ruzsnavszky, Olga; Dienes, Beatrix; Szentesi, Péter; Friedrich, Oliver; Csernoch, László

    2016-12-15

    Marijuana was found to cause muscle weakness, although the exact regulatory role of its receptors (CB1 cannabinoid receptor; CB1R) in the excitation-contraction coupling (ECC) of mammalian skeletal muscle remains unknown. We found that CB1R activation or its knockout did not affect muscle force directly, whereas its activation decreased the Ca 2+ -sensitivity of the contractile apparatus and made the muscle fibres more prone to fatigue. We demonstrate that CB1Rs are not connected to the inositol 1,4,5-trisphosphate pathway either in myotubes or in adult muscle fibres. By contrast, CB1Rs constitutively inhibit sarcoplasmic Ca 2+ release and sarcoplasmic reticulum Ca 2+ ATPase during ECC in a G i/o protein-mediated way in adult skeletal muscle fibres but not in myotubes. These results help with our understanding of the physiological effects and pathological consequences of CB1R activation in skeletal muscle and may be useful in the development of new cannabinoid drugs. Marijuana was found to cause muscle weakness, although it is unknown whether it affects the muscles directly or modulates only the motor control of the central nervous system. Although the presence of CB1 cannabinoid receptors (CB1R), which are responsible for the psychoactive effects of the drug in the brain, have recently been demonstrated in skeletal muscle, it is unclear how CB1R-mediated signalling affects the contraction and Ca²⁺ homeostasis of mammalian skeletal muscle. In the present study, we demonstrate that in vitro CB1R activation increased muscle fatigability and decreased the Ca 2+ -sensitivity of the contractile apparatus, whereas it did not alter the amplitude of single twitch contractions. In myotubes, CB1R agonists neither evoked, nor influenced inositol 1,4,5-trisphosphate (IP 3 )-mediated Ca 2+ transients, nor did they alter excitation-contraction coupling. By contrast, in isolated muscle fibres of wild-type mice, although CB1R agonists did not evoke IP 3 -mediated Ca 2

  1. Modulation of cardiac contractility by the phospholamban/SERCA2a regulatome.

    Science.gov (United States)

    Kranias, Evangelia G; Hajjar, Roger J

    2012-06-08

    Heart disease remains the leading cause of death and disability in the Western world. Current therapies aim at treating the symptoms rather than the subcellular mechanisms, underlying the etiology and pathological remodeling in heart failure. A universal characteristic, contributing to the decreased contractile performance in human and experimental failing hearts, is impaired calcium sequestration into the sarcoplasmic reticulum (SR). SR calcium uptake is mediated by a Ca(2+)-ATPase (SERCA2), whose activity is reversibly regulated by phospholamban (PLN). Dephosphorylated PLN is an inhibitor of SERCA and phosphorylation of PLN relieves this inhibition. However, the initial simple view of a PLN/SERCA regulatory complex has been modified by our recent identification of SUMO, S100 and the histidine-rich Ca-binding protein as regulators of SERCA activity. In addition, PLN activity is regulated by 2 phosphoproteins, the inhibitor-1 of protein phosphatase 1 and the small heat shock protein 20, which affect the overall SERCA-mediated Ca-transport. This review will highlight the regulatory mechanisms of cardiac contractility by the multimeric SERCA/PLN-ensemble and the potential for new therapeutic avenues targeting this complex by using small molecules and gene transfer methods.

  2. Cardiac ryanodine receptor in metabolic syndrome: is JTV519 (K201 future therapy?

    Directory of Open Access Journals (Sweden)

    Dincer UD

    2012-04-01

    Full Text Available U Deniz DincerDepartment of Pharmacology, Ufuk University School of Medicine. Mevlana Bulvari, Balgat, Ankara, TurkeyAbstract: Metabolic syndrome is characterized by a combination of obesity, hypertension, insulin resistance, dyslipidemia, and impaired glucose tolerance. This multifaceted syndrome is often accompanied by a hyperdynamic circulatory state characterized by increased blood pressure, total blood volume, cardiac output, and metabolic tissue demand. Experimental, epidemiological, and clinical studies have demonstrated that patients with metabolic syndrome have significantly elevated cardiovascular morbidity and mortality rates. One of the main and frequent complications seen in metabolic syndrome is cardiovascular disease. The primary endpoints of cardiometabolic risk are coronary and peripheral arterial disease, myocardial infarction, congestive heart failure, arrhythmia, and stroke. Alterations in expression and/or functioning of several key proteins involved in regulating and maintaining ionic homeostasis can cause cardiac disturbances. One such group of proteins is known as ryanodine receptors (intracellular calcium release channels, which are the major channels through which Ca2+ ions leave the sarcoplasmic reticulum, leading to cardiac muscle contraction. The economic cost of metabolic syndrome and its associated complications has a significant effect on health care budgets. Improvements in body weight, blood lipid profile, and hyperglycemia can reduce cardiometabolic risk. However, constant hyperadrenergic stimulation still contributes to the burden of disease. Normalization of the hyperdynamic circulatory state with conventional therapies is the most reasonable therapeutic strategy to date. JTV519 (K201 is a newly developed 1,4-benzothiazepine drug with antiarrhythmic and cardioprotective properties. It appears to be very effective in not only preventing but also in reversing the characteristic myocardial changes and preventing

  3. The Complex Role of Store Operated Calcium Entry Pathways and Related Proteins in the Function of Cardiac, Skeletal and Vascular Smooth Muscle Cells

    Directory of Open Access Journals (Sweden)

    Javier Avila-Medina

    2018-03-01

    Full Text Available Cardiac, skeletal, and smooth muscle cells shared the common feature of contraction in response to different stimuli. Agonist-induced muscle's contraction is triggered by a cytosolic free Ca2+ concentration increase due to a rapid Ca2+ release from intracellular stores and a transmembrane Ca2+ influx, mainly through L-type Ca2+ channels. Compelling evidences have demonstrated that Ca2+ might also enter through other cationic channels such as Store-Operated Ca2+ Channels (SOCCs, involved in several physiological functions and pathological conditions. The opening of SOCCs is regulated by the filling state of the intracellular Ca2+ store, the sarcoplasmic reticulum, which communicates to the plasma membrane channels through the Stromal Interaction Molecule 1/2 (STIM1/2 protein. In muscle cells, SOCCs can be mainly non-selective cation channels formed by Orai1 and other members of the Transient Receptor Potential-Canonical (TRPC channels family, as well as highly selective Ca2+ Release-Activated Ca2+ (CRAC channels, formed exclusively by subunits of Orai proteins likely organized in macromolecular complexes. This review summarizes the current knowledge of the complex role of Store Operated Calcium Entry (SOCE pathways and related proteins in the function of cardiac, skeletal, and vascular smooth muscle cells.

  4. Computer modeling of siRNA knockdown effects indicates an essential role of the Ca2+ channel alpha2delta-1 subunit in cardiac excitation-contraction coupling.

    Science.gov (United States)

    Tuluc, Petronel; Kern, Georg; Obermair, Gerald J; Flucher, Bernhard E

    2007-06-26

    L-type Ca(2+) currents determine the shape of cardiac action potentials (AP) and the magnitude of the myoplasmic Ca(2+) signal, which regulates the contraction force. The auxiliary Ca(2+) channel subunits alpha(2)delta-1 and beta(2) are important regulators of membrane expression and current properties of the cardiac Ca(2+) channel (Ca(V)1.2). However, their role in cardiac excitation-contraction coupling is still elusive. Here we addressed this question by combining siRNA knockdown of the alpha(2)delta-1 subunit in a muscle expression system with simulation of APs and Ca(2+) transients by using a quantitative computer model of ventricular myocytes. Reconstitution of dysgenic muscle cells with Ca(V)1.2 (GFP-alpha(1C)) recapitulates key properties of cardiac excitation-contraction coupling. Concomitant depletion of the alpha(2)delta-1 subunit did not perturb membrane expression or targeting of the pore-forming GFP-alpha(1C) subunit into junctions between the outer membrane and the sarcoplasmic reticulum. However, alpha(2)delta-1 depletion shifted the voltage dependence of Ca(2+) current activation by 9 mV to more positive potentials, and it slowed down activation and inactivation kinetics approximately 2-fold. Computer modeling revealed that the altered voltage dependence and current kinetics exert opposing effects on the function of ventricular myocytes that in total cause a 60% prolongation of the AP and a 2-fold increase of the myoplasmic Ca(2+) concentration during each contraction. Thus, the Ca(2+) channel alpha(2)delta-1 subunit is not essential for normal Ca(2+) channel targeting in muscle but is a key determinant of normal excitation and contraction of cardiac muscle cells, and a reduction of alpha(2)delta-1 function is predicted to severely perturb normal heart function.

  5. Cyclopiazonic Acid Is Complexed to a Divalent Metal Ion When Bound to the Sarcoplasmic Reticulum Ca2+-ATPase

    DEFF Research Database (Denmark)

    Laursen, Mette; Bublitz, Maike; Moncoq, Karine

    2009-01-01

    is expected to be part of the cytoplasmic cation access pathway. Our model is consistent with the biochemical data on CPA function and provides new measures in structure-based drug design targeting Ca2+-ATPases, e. g. from pathogens. We also present an extended structural basis of ATP modulation pinpointing...

  6. Serca2a and Na+/Ca2+ exchanger are involved in left ventricular function following cardiac remodelling of female rats treated with anabolic androgenic steroid

    International Nuclear Information System (INIS)

    Nascimento, Andrews Marques do; Lima, Ewelyne Miranda de; Brasil, Girlandia Alexandre; Caliman, Izabela Facco; Silva, Josiane Fernandes da; Lemos, Virgínia Soares; Andrade, Tadeu Uggere de; Bissoli, Nazaré Souza

    2016-01-01

    Anabolic-androgenic steroids are misused, including by women, but little is known about the cardiovascular effects of these drugs on women. Aim: To evaluated the effects of nandrolone decanoate (ND) and resistive physical exercise on cardiac contractility in young female rats. Main methods: Female Wistar rats were separated into 4 groups: C (untrained animals); E (animals were submitted to resistance exercise by jumping in water 5 times per week); ND (animals were treated with ND, 20 mg/kg/week for 4 weeks); and NDE (trained and treated). The haemodynamic parameters (+ dP/dt max , − dP/dt min and Tau) were assessed in the left ventricle. The heart was collected for histological analyses and collagen deposition. The gastrocnemius muscle was weighed, and hypertrophy was assessed by the ratio of their weights to gastrocnemius/tibia length. The expression of calcium handling proteins was measured by western blot analysis. Results: ND treatment and physical exercise increased cardiac contractility and relaxation. In addition, ND promoted increases in phospholamban phosphorylated (p-PLB) and isoforms of sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA2a) expression, while resistance exercise increased the phosphorylation of PLB and expression of Na + /Ca 2+ exchangers (NCX). Cardiac hypertrophy and collagen deposition were observed after ND treatment. Conclusion: Regulatory components of cytosolic calcium, such as SERCA2a and p-PLB, play important roles in modulating the contractility and relaxation effects of ND in females. - Highlights: • ND and resistive exercise enhanced the cardiac function and increased expression of cytosolic calcium regulatory components.

  7. Voltage-dependent modulation of cardiac ryanodine receptors (RyR2 by protamine.

    Directory of Open Access Journals (Sweden)

    Paula L Diaz-Sylvester

    Full Text Available It has been reported that protamine (>10 microg/ml blocks single skeletal RyR1 channels and inhibits RyR1-mediated Ca2+ release from sarcoplasmic reticulum microsomes. We extended these studies to cardiac RyR2 reconstituted into planar lipid bilayers. We found that protamine (0.02-20 microg/ml added to the cytosolic surface of fully activated RyR2 affected channel activity in a voltage-dependent manner. At membrane voltage (V(m; SR lumen-cytosol = 0 mV, protamine induced conductance transitions to several intermediate states (substates as well as full block of RyR2. At V(m>10 mV, the substate with the highest level of conductance was predominant. Increasing V(m from 0 to +80 mV, decreased the number of transitions and residence of the channel in this substate. The drop in current amplitude (full opening to substate had the same magnitude at 0 and +80 mV despite the approximately 3-fold increase in amplitude of the full opening. This is more similar to rectification of channel conductance induced by other polycations than to the action of selective conductance modifiers (ryanoids, imperatoxin. A distinctive effect of protamine (which might be shared with polylysines and histones but not with non-peptidic polycations is the activation of RyR2 in the presence of nanomolar cytosolic Ca2+ and millimolar Mg2+ levels. Our results suggest that RyRs would be subject to dual modulation (activation and block by polycationic domains of neighboring proteins via electrostatic interactions. Understanding these interactions could be important as such anomalies may be associated with the increased RyR2-mediated Ca2+ leak observed in cardiac diseases.

  8. Effect of experimental hyperthyroidism on protein turnover in skeletal and cardiac muscle.

    Science.gov (United States)

    Carter, W J; Van Der Weijden Benjamin, W S; Faas, F H

    1980-10-01

    Since experimental hyperthyroidism reduces skeletal muscle mass while simultaneously increasing cardiac muscle mass, the effect of hyperthyroidism on muscle protein degradation was compared in skeletal and cardiac muscle. Pulse-labeling studies using (3H) leucine and (14C) carboxyl labeled aspartate and glutamate were carried out. Hyperthyroidism caused a 25%-29% increase in protein breakdown in both sarcoplasmic and myofibrillar fractions of skeletal muscle. Increased muscle protein degradation may be a major factor in the development of skeletal muscle wasting and weakness in hyperthyroidism. In contrast, protein breakdown appeared to be reduced 22% in the sarcoplasmic fraction of hyperthyroid heart muscle and was unchanged in the myofibrillar fraction. Possible reasons for the contrasting effects of hyperthyroidism on skeletal and cardiac muscle include increased sensitivity of the hyperthyroid heart to catecholamines, increased cardiac work caused by the hemodynamic effects of hyperthyroidism, and a different direct effect of thyroid hormone at the nuclear level in cardiac as opposed to skeletal muscle.

  9. Recirculating cardiac delivery of AAV2/1SERCA2a improves myocardial function in an experimental model of heart failure in large animals.

    Science.gov (United States)

    Byrne, M J; Power, J M; Preovolos, A; Mariani, J A; Hajjar, R J; Kaye, D M

    2008-12-01

    Abnormal excitation-contraction coupling is a key pathophysiologic component of heart failure (HF), and at a molecular level reduced expression of the sarcoplasmic reticulum (SR) Ca(2+) ATPase (SERCA2a) is a major contributor. Previous studies in small animals have suggested that restoration of SERCA function is beneficial in HF. Despite this promise, the means by which this information might be translated into potential clinical application remains uncertain. Using a recently established cardiac-directed recirculating method of gene delivery, we administered adeno-associated virus 2 (AAV2)/1SERCA2a to sheep with pacing-induced HF. We explored the effects of differing doses of AAV2/1SERCA2a (low 1 x 10(10) d.r.p.; medium 1 x 10(12) d.r.p. and high 1 x 10(13) d.r.p.) in conjunction with an intra-coronary delivery group (2.5 x 10(13) d.r.p.). At the end of the study, haemodynamic, echocardiographic, histopathologic and molecular biologic assessments were performed. Cardiac recirculation delivery of AAV2/1SERCA2a elicited a dose-dependent improvement in cardiac performance determined by left ventricular pressure analysis, (+d P/d t(max); low dose -220+/-70, P>0.05; medium dose 125+/-53, P0.05; medium dose 1+/-2, P>0.05; high dose 6.5+/-3.9, Preversal of the HF molecular phenotype. In contrast, direct intra-coronary infusion did not elicit any effect on ventricular function. As such, AAV2/1SERCA2a elicits favourable functional and molecular actions when delivered in a mechanically targeted manner in an experimental model of HF. These observations lay a platform for potential clinical translation.

  10. Serca2a and Na{sup +}/Ca{sup 2+} exchanger are involved in left ventricular function following cardiac remodelling of female rats treated with anabolic androgenic steroid

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Andrews Marques do; Lima, Ewelyne Miranda de; Brasil, Girlandia Alexandre; Caliman, Izabela Facco [Department of Physiological Sciences, Federal University of Espirito Santo, Vitória, Espirito Santo (Brazil); Silva, Josiane Fernandes da; Lemos, Virgínia Soares [Department of Physiology and Biophysic, Federal University of Minas Gerais, Minas Gerais (Brazil); Andrade, Tadeu Uggere de [Department of Pharmacy, University Vila Velha, Vila Velha, Espirito Santo (Brazil); Bissoli, Nazaré Souza, E-mail: nazarebissoli@gmail.com [Department of Physiological Sciences, Federal University of Espirito Santo, Vitória, Espirito Santo (Brazil)

    2016-06-15

    Anabolic-androgenic steroids are misused, including by women, but little is known about the cardiovascular effects of these drugs on women. Aim: To evaluated the effects of nandrolone decanoate (ND) and resistive physical exercise on cardiac contractility in young female rats. Main methods: Female Wistar rats were separated into 4 groups: C (untrained animals); E (animals were submitted to resistance exercise by jumping in water 5 times per week); ND (animals were treated with ND, 20 mg/kg/week for 4 weeks); and NDE (trained and treated). The haemodynamic parameters (+ dP/dt{sub max}, − dP/dt{sub min} and Tau) were assessed in the left ventricle. The heart was collected for histological analyses and collagen deposition. The gastrocnemius muscle was weighed, and hypertrophy was assessed by the ratio of their weights to gastrocnemius/tibia length. The expression of calcium handling proteins was measured by western blot analysis. Results: ND treatment and physical exercise increased cardiac contractility and relaxation. In addition, ND promoted increases in phospholamban phosphorylated (p-PLB) and isoforms of sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA2a) expression, while resistance exercise increased the phosphorylation of PLB and expression of Na{sup +}/Ca{sup 2+} exchangers (NCX). Cardiac hypertrophy and collagen deposition were observed after ND treatment. Conclusion: Regulatory components of cytosolic calcium, such as SERCA2a and p-PLB, play important roles in modulating the contractility and relaxation effects of ND in females. - Highlights: • ND and resistive exercise enhanced the cardiac function and increased expression of cytosolic calcium regulatory components.

  11. [Sodium hydrosulfide improves cardiac functions and structures in rats with chronic heart failure].

    Science.gov (United States)

    Li, Xiao-hui; Zhang, Chao-ying; Zhang, Ting

    2011-11-22

    To explore the effects of sodium hydrosulfide (NaHS), a hydrogen sulphide (H(2)S) donor, on cardiac functions and structures in rats with chronic heart failure induced by volume overload and examine its influence on cardiac remodelling. A total of 47 SD rats (120 - 140 g) were randomly divided into 5 groups:shunt group (n = 11), sham group (n = 8), shunt + NaHS group (n = 10), sham + NaHS group (n = 8) and shunt + phentolamine group (n = 10). The rat model of chronic heart failure was induced by abdominal aorta-inferior vena cava puncture. At Week 8 post-operation, hemodynamic parameters, microstructures and ultrastructures of myocardial tissues were analyzed. Extracellular collagen content in myocardial tissues was analyzed after Sirius red staining. Right ventricular hydroxyproline concentration was determined and compared. At Week 8 post-operation, compared with the sham operation and shunt + NaHS groups, the shunt group showed significantly increased right ventricular systolic pressure (RVSP) and right ventricular end diastolic pressure (RVEDP) (mm Hg: 35.2 ± 3.9 vs 21.4 ± 3.7 and 28.1 ± 2.7, 32 ± 5 vs 21 ± 4 and 26 ± 4, all P vs 2336 ± 185 and 1835 ± 132, 1331 ± 107 vs 2213 ± 212 and 1768 ± 116, all P non-uniformly in the shunt group, some fiber mitochondria were highly swollen and contained vacuoles. And sarcoplasmic reticulum appeared slightly dilated. Polarized microscopy indicated that, collagen content (particularly type-I collagen) increased in the shunt group compared with the sham operation group. Additionally, compared with the shunt group, the shunt and NaHS treatment groups showed an amelioration of myocardial damage, an alleviation of myocardial fiber changes and a decrease in myocardial collagen content (particularly type-I collagen). Compared with the sham operation and shunt + NaHS groups, the shunt group displayed increased right ventricular hydroxyproline (mg×g(-1)·pro: 1.32 ± 0.25 vs 0.89 ± 0.18 and 0.83 ± 0.19, all P < 0

  12. Mutations in calmodulin cause ventricular tachycardia and sudden cardiac death

    DEFF Research Database (Denmark)

    Nyegaard, Mette; Overgaard, Michael Toft; Sondergaard, M.T.

    2012-01-01

    a substantial part of sudden cardiac deaths in young individuals. Mutations in RYR2, encoding the cardiac sarcoplasmic calcium channel, have been identified as causative in approximately half of all dominantly inherited CPVT cases. Applying a genome-wide linkage analysis in a large Swedish family with a severe......Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a devastating inherited disorder characterized by episodic syncope and/or sudden cardiac arrest during exercise or acute emotion in individuals without structural cardiac abnormalities. Although rare, CPVT is suspected to cause...... calmodulin-binding-domain peptide at low calcium concentrations. We conclude that calmodulin mutations can cause severe cardiac arrhythmia and that the calmodulin genes are candidates for genetic screening of individual cases and families with idiopathic ventricular tachycardia and unexplained sudden cardiac...

  13. CaMKII Regulation of Cardiac Ryanodine Receptors and Inositol Triphosphate Receptors

    Directory of Open Access Journals (Sweden)

    Emmanuel eCamors

    2014-05-01

    Full Text Available Ryanodine receptors (RyRs and inositol triphosphate receptors (InsP3Rs are structurally related intracellular calcium release channels that participate in multiple primary or secondary amplified Ca2+ signals, triggering muscle contraction and oscillatory Ca2+ waves, or activating transcription factors. In the heart, RyRs play an indisputable role in the process of excitation-contraction coupling as the main pathway for Ca2+ release from sarcoplasmic reticulum (SR, and a less prominent role in the process of excitation-transcription coupling. Conversely, InsP3Rs are believed to contribute in subtle ways, only, to contraction of the heart, and in more important ways to regulation of transcription factors. Because uncontrolled activity of either RyRs or InsP3Rs may elicit life-threatening arrhythmogenic and/or remodeling Ca2+ signals, regulation of their activity is of paramount importance for normal cardiac function. Due to their structural similarity, many regulatory factors, accessory proteins, and posttranslational processes are equivalent for RyRs and InsP3Rs. Here we discuss regulation of RyRs and InsP3Rs by CaMKII phosphorylation, but touch on other kinases whenever appropriate. CaMKII is emerging as a powerful modulator of RyR and InsP3R activity but interestingly, some of the complexities and controversies surrounding phosphorylation of RyRs also apply to InsP3Rs, and a clear-cut effect of CaMKII on either channel eludes investigators for now. Nevertheless, some effects of CaMKII on global cellular activity, such as SR Ca2+ leak or force-frequency potentiation, appear clear now, and this constrains the limits of the controversies and permits a more tractable approach to elucidate the effects of phosphorylation at the single channel level.

  14. [Changes induced by hypertonic solutions in the transportation of calcium by the cardiac reticular sarcoplasma].

    Science.gov (United States)

    Sierra, M; Holguín, J A

    1979-01-01

    In the sarcoplasmic reticulum of the myocardium, celular organell which function is to regulate the cytoplasmic concentration of calcium in contraction and relaxation, we have studied the effect of hypertonic solutions of sucrose between 1 and 6.96 times the normal tonicity in order to observe the behavior of the internal linked or free calcium of this structure, as well as to prove the hypothesis that hypertonic solutions encourage the calcium exit of the sarcoplasmatic reticulum with the resulting signs of contractures. The following results were obtained: 1. The ATP hydrolisis and calcium transport rate are 14% and 90% respectively of the maximum speeds of 10(-5) M in calcium, while for concentrations of 10(-7) M or ess of the said cation, the transport rates and the ATPase do not reach 5% of the maximum values. 2. Between 1 and 2.54 times of the normal tonicity the calcium uptake remains between 400 and 500 nmoles of calcium/mg protein/min, the transported amount of calcium varies between 14 and 16 nmoles/mg protein and the rate of the ATP hydrolysis increases a 37% to 0.4 M in sucrose. 3. Between 0.4 and 1.2 M in sucrose of 2.54 to 6.96 times the isotonicity, the calcium transport rate velocity as well as the ATP hydrolisis are strongly inhibited. The vesicles volume minimizes and the amount of linked calcium remains within the control values, proving that the capacity of linking this cathion is independent from sarcoplasmic reticulum volume. These results show that the sarcoplasmic reticulum is involved in the contractures induced by hypertonic solutions in intact cells, since the osmolarity increase produces changes of volume which results in a decrease of the calcium transportation velocity or in an increase of the exit of said cathion.

  15. 4-Phenylbutyric Acid Reveals Good Beneficial Effects on Vital Organ Function via Anti-Endoplasmic Reticulum Stress in Septic Rats.

    Science.gov (United States)

    Liu, Liangming; Wu, Huiling; Zang, JiaTao; Yang, Guangming; Zhu, Yu; Wu, Yue; Chen, Xiangyun; Lan, Dan; Li, Tao

    2016-08-01

    Sepsis and septic shock are the common complications in ICUs. Vital organ function disorder contributes a critical role in high mortality after severe sepsis or septic shock, in which endoplasmic reticulum stress plays an important role. Whether anti-endoplasmic reticulum stress with 4-phenylbutyric acid is beneficial to sepsis and the underlying mechanisms are not known. Laboratory investigation. State Key Laboratory of Trauma, Burns and Combined Injury. Sprague-Dawley rats. Using cecal ligation and puncture-induced septic shock rats, lipopolysaccharide-treated vascular smooth muscle cells, and cardiomyocytes, effects of 4-phenylbutyric acid on vital organ function and the relationship with endoplasmic reticulum stress and endoplasmic reticulum stress-mediated inflammation, apoptosis, and oxidative stress were observed. Conventional treatment, including fluid resuscitation, vasopressin, and antibiotic, only slightly improved the hemodynamic variable, such as mean arterial blood pressure and cardiac output, and slightly improved the vital organ function and the animal survival of septic shock rats. Supplementation of 4-phenylbutyric acid (5 mg/kg; anti-endoplasmic reticulum stress), especially administered at early stage, significantly improved the hemodynamic variables, vital organ function, such as liver, renal, and intestinal barrier function, and animal survival in septic shock rats. 4-Phenylbutyric acid application inhibited the endoplasmic reticulum stress and endoplasmic reticulum stress-related proteins, such as CCAAT/enhancer-binding protein homologous protein in vital organs, such as heart and superior mesenteric artery after severe sepsis. Further studies showed that 4-phenylbutyric acid inhibited endoplasmic reticulum stress-mediated cytokine release, apoptosis, and oxidative stress via inhibition of nuclear factor-κB, caspase-3 and caspase-9, and increasing glutathione peroxidase and superoxide dismutase expression, respectively. Anti

  16. Comparative profiling of sarcoplasmic phosphoproteins in ovine muscle with different color stability.

    Science.gov (United States)

    Li, Meng; Li, Zheng; Li, Xin; Xin, Jianzeng; Wang, Ying; Li, Guixia; Wu, Liguo; Shen, Qingwu W; Zhang, Dequan

    2018-02-01

    The phosphorylation of sarcoplasmic proteins in postmortem muscles was investigated in relationship to color stability in the present study. Although no difference was observed in the global phosphorylation level of sarcoplasmic proteins, difference was determined in the phosphorylation levels of individual protein bands from muscles with different color stability. Correlation analysis and liquid chromatography - tandem mass spectrometry (LC-MS/MS) identification of phosphoproteins showed that most of the color stability-related proteins were glycolytic enzymes. Interestingly, the phosphorylation level of myoglobin was inversely related to meat color stability. As the phosphorylation of myoglobin increased, color stability based on a ∗ value decreased and metMb content increased. In summary, the study revealed that protein phosphorylation might play a role in the regulation of meat color stability probably by regulating glycolysis and the redox stability of myoglobin, which might be affected by the phosphorylation of myoglobin. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Time Course of the Response of Myofibrillar and Sarcoplasmic Protein Metabolism to Unweighting of the Soleus Muscle

    Science.gov (United States)

    Munoz, Kathryn A.; Satarug, Soisungwan; Tischler, Marc E.

    1993-01-01

    Contributions of altered in vivo protein synthesis and degradation to unweighting atrophy of the soleus muscle in tail-suspended young female rats were analyzed daily for up to 6 days. Specific changes in myofibrillar and sarcoplasmic proteins were also evaluated to assess their contributions to the loss of total protein. Synthesis of myofibrillar and sarcoplasmic proteins was estimated by intramuscular (IM) injection and total protein by intraperitoneal (IP) injection of flooding doses of H-3-phenylaianine. Total protein loss was greatest during the first 3 days following suspension and was a consequence of the loss of myofibrillar rather than sarcoplasmic proteins. However, synthesis of total myofibrillar and sarcoplasmic proteins diminished in parallel beginning in the first 24 hours. Therefore sarcoplasmic proteins must be spared due to a decrease in their degradation. In contrast, myofibrillar protein degradation increased, thus explaining the elevated degradation of the total pool. Following 72 hours of suspension, protein synthesis remained low, but the rate of myofibrillar protein loss diminished, suggesting a slowing of degradation. These various results show acute loss of protein during unweighting atrophy is a consequence of decreased synthesis and increased degradation of myofibrillar proteins, and sarcoplasmic proteins are spared due to slower degradation, likely explaining the sparing of plasma membrane receptors. Based on other published data, we propose that the slowing of atrophy after the initial response may be attributed to an increased effect of insulin.

  18. A model of propagating calcium-induced calcium release mediated by calcium diffusion

    NARCIS (Netherlands)

    Backx, P. H.; de Tombe, P. P.; van Deen, J. H.; Mulder, B. J.; ter Keurs, H. E.

    1989-01-01

    The effect of sudden local fluctuations of the free sarcoplasmic [Ca++]i in cardiac cells on calcium release and calcium uptake by the sarcoplasmic reticulum (SR) was calculated with the aid of a simplified model of SR calcium handling. The model was used to evaluate whether propagation of calcium

  19. A model of cardiac ryanodine receptor gating predicts experimental Ca2+-dynamics and Ca2+-triggered arrhythmia in the long QT syndrome

    Science.gov (United States)

    Wilson, Dan; Ermentrout, Bard; Němec, Jan; Salama, Guy

    2017-09-01

    Abnormal Ca2+ handling is well-established as the trigger of cardiac arrhythmia in catecholaminergic polymorphic ventricular tachycardia and digoxin toxicity, but its role remains controversial in Torsade de Pointes (TdP), the arrhythmia associated with the long QT syndrome (LQTS). Recent experimental results show that early afterdepolarizations (EADs) that initiate TdP are caused by spontaneous (non-voltage-triggered) Ca2+ release from Ca2+-overloaded sarcoplasmic reticulum (SR) rather than the activation of the L-type Ca2+-channel window current. In bradycardia and long QT type 2 (LQT2), a second, non-voltage triggered cytosolic Ca2+ elevation increases gradually in amplitude, occurs before overt voltage instability, and then precedes the rise of EADs. Here, we used a modified Shannon-Puglisi-Bers model of rabbit ventricular myocytes to reproduce experimental Ca2+ dynamics in bradycardia and LQT2. Abnormal systolic Ca2+-oscillations and EADs caused by SR Ca2+-release are reproduced in a modified 0-dimensional model, where 3 gates in series control the ryanodine receptor (RyR2) conductance. Two gates control RyR2 activation and inactivation and sense cytosolic Ca2+ while a third gate senses luminal junctional SR Ca2+. The model predicts EADs in bradycardia and low extracellular [K+] and cessation of SR Ca2+-release terminate salvos of EADs. Ca2+-waves, systolic cell-synchronous Ca2+-release, and multifocal diastolic Ca2+ release seen in subcellular Ca2+-mapping experiments are observed in the 2-dimensional version of the model. These results support the role of SR Ca2+-overload, abnormal SR Ca2+-release, and the subsequent activation of the electrogenic Na+/Ca2+-exchanger as the mechanism of TdP. The model offers new insights into the genesis of cardiac arrhythmia and new therapeutic strategies.

  20. Endoplasmic Reticulum Stress and Obesity.

    Science.gov (United States)

    Yilmaz, Erkan

    2017-01-01

    In recent years, the world has seen an alarming increase in obesity and closely associated with insulin resistance which is a state of low-grade inflammation, the latter characterized by elevated levels of proinflammatory cytokines in blood and tissues. A shift in energy balance alters systemic metabolic regulation and the important role that chronic inflammation, endoplasmic reticulum (ER) dysfunction, and activation of the unfolded protein response (UPR) play in this process.Why obesity is so closely associated with insulin resistance and inflammation is not understood well. This suggests that there are probably other causes for obesity-related insulin resistance and inflammation. One of these appears to be endoplasmic reticulum (ER) stress.The ER is a vast membranous network responsible for the trafficking of a wide range of proteins and plays a central role in integrating multiple metabolic signals critical in cellular homeostasis. Conditions that may trigger unfolded protein response activation include increased protein synthesis, the presence of mutant or misfolded proteins, inhibition of protein glycosylation, imbalance of ER calcium levels, glucose and energy deprivation, hypoxia, pathogens or pathogen-associated components and toxins. Thus, characterizing the mechanisms contributing to obesity and identifying potential targets for its prevention and treatment will have a great impact on the control of associated conditions, particularly T2D.

  1. Endoplasmic reticulum stress in lung disease

    Directory of Open Access Journals (Sweden)

    Stefan J. Marciniak

    2017-06-01

    Full Text Available Exposure to inhaled pollutants, including fine particulates and cigarette smoke is a major cause of lung disease in Europe. While it is established that inhaled pollutants have devastating effects on the genome, it is now recognised that additional effects on protein folding also drive the development of lung disease. Protein misfolding in the endoplasmic reticulum affects the pathogenesis of many diseases, ranging from pulmonary fibrosis to cancer. It is therefore important to understand how cells respond to endoplasmic reticulum stress and how this affects pulmonary tissues in disease. These insights may offer opportunities to manipulate such endoplasmic reticulum stress pathways and thereby cure lung disease.

  2. Design and characterization of self-assembled fish sarcoplasmic protein-alginate nanocomplexes

    DEFF Research Database (Denmark)

    Boutrup Stephansen, Karen; Mattebjerg, Maria Ahlm; Wattjes, Jasper

    2015-01-01

    Macrostructures based on natural polymers are subject to large attention, as the application range is wide within the food and pharmaceutical industries. In this study we present nanocomplexes (NCXs) made from electrostatic self-assembly between negatively charged alginate and positively charged...... fish sarcoplasmic proteins (FSP), prepared by bulk mixing. A concentration screening revealed that there was a range of alginate and FSP concentrations where stable NCXs with similar properties were formed, rather than two exact concentrations. The size of the NCXs was 293 +/- 3 nm, and the zeta...

  3. Critical roles of hydrophobicity and orientation of side chains for inactivation of sarcoplasmic reticulum Ca2+-ATPase with thapsigargin and thapsigargin analogs

    DEFF Research Database (Denmark)

    Winther, Anne-Marie Lund; Liu, Huizhen; Sonntag, Yonathan

    2010-01-01

    fluorescence data to show how Tg and chemical analogs of the compound with modified or removed side chains bind to isolated SERCA 1a membranes. This occurs by uptake via the membrane lipid followed by insertion into a resident intramembranous binding site with few adaptative changes. Our binding data indicate...... that a balanced hydrophobicity and accurate positioning of the side chains, provided by the central guaianolide ring structure, defines a pharmacophore of Tg that governs both high affinity and access to the protein-binding site. Tg analogs substituted with long linkers at O-8 extend from the binding site between...... transmembrane segments to the putative N-terminal Ca(2+) entry pathway. The long chain analogs provide a rational basis for the localization of the linker, the presence of which is necessary for enabling prostate-specific antigen to cleave peptide-conjugated prodrugs targeting SERCA of cancer cells (Denmeade, S...

  4. Effects of Preslaughter Stress Levels on the Post-mortem Sarcoplasmic Proteomic Profile of Gilthead Seabream Muscle

    DEFF Research Database (Denmark)

    Silva, Tomé Santos; Cordeiro, Odete D; Matos, Elisabete D.

    2012-01-01

    identification was performed by MALDI-TOF-TOF MS. Analysis of the results indicates changes on several cellular pathways, with some of these changes being attributable to oxidative and proteolytic activity on sarcoplasmic proteins, together with leaking of myofibrillar proteins. These processes appear to have...

  5. Gαq protein carboxyl terminus imitation polypeptide GCIP-27 improves cardiac function in chronic heart failure rats.

    Directory of Open Access Journals (Sweden)

    Xiao Lan Lu

    Full Text Available Gαq protein carboxyl terminus imitation polypeptide (GCIP-27 has been shown to alleviate pathological cardiomyocyte hypertrophy induced by various factors. Pathological cardiac hypertrophy increases the morbidity and mortality of cardiovascular diseases while it compensates for poor heart function. This study was designed to investigate the effects of GCIP-27 on heart function in rats with heart failure induced by doxorubicin.Forty-eight rats were randomly divided into the following six groups receiving vehicle (control, doxorubicin (Dox, losartan (6 mg/kg, i.g. and three doses of GCIP-27 (10, 30, 90 μg/kg; i.p., bid, respectively. Heart failure was induced by Dox, which was administered at a 20 mg/kg cumulative dose. After 10 weeks of treatment, we observed that GCIP-27 (30, 90 μg/kg significantly increased ejection fraction, fraction shortening, stroke volume and sarcoplasmic reticulum Ca2+ ATPase activity of Dox-treated hearts. Additionally, GCIP-27 decreased myocardial injury, heart weight index and left ventricular weight index, fibrosis and serum cardiac troponin-I concentration in Dox-treated mice. Immunohistochemistry, western blotting and real-time PCR experiments indicated that GCIP-27 (10-90 μg/kg could markedly upregulate the protein expression of myocardial α-myosin heavy chain (MHC, Bcl-2, protein kinase C (PKC ε and phosphorylated extracellular signal-regulated kinase (p-ERK 1/2 as well as the mRNA expression of α-MHC, but downregulated the expression of β-MHC, Bax and PKC βII, and the mRNA expression levels of β-MHC in Dox-treated mice. It was also found that GCIP-27 (30, 90 μg/L decreased cell size and protein content of cardiomyocytes significantly in vitro by comparison of Dox group.GCIP-27 could effectively ameliorate heart failure development induced by Dox. PKC-ERK1/2 signaling might represent the underlying mechanism of the beneficial effects of GCIP-27.

  6. The endoplasmic reticulum stress response in disease ...

    African Journals Online (AJOL)

    Rafael Vincent M. Manalo

    2017-07-12

    Jul 12, 2017 ... Review. The endoplasmic reticulum stress response in disease pathogenesis and pathophysiology .... This is an open access article under the CC BY-NC-ND license ... chain binding protein (BIP); however, ER stress permits the release, .... drugs designed to alleviate it often cause more harm long-term.

  7. Cardiac rehabilitation

    Science.gov (United States)

    ... rehab; Heart failure - cardiac rehab References Anderson L, Taylor RS. Cardiac rehabilitation for people with heart disease: ... of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed ...

  8. 1H nuclear magnetic resonance studies of sarcoplasmic oxygenation in the red cell-perfused rat heart

    OpenAIRE

    Jelicks, L.A.; Wittenberg, B.A.

    1995-01-01

    The proximal histidine N delta H proton of deoxymyoglobin experiences a large hyperfine shift resulting in its 1H nuclear magnetic resonance (NMR) signal appearing at approximately 76 ppm (at 35 degrees C), downfield of the diamagnetic spectral region. 1H NMR of this proton is used to monitor sarcoplasmic oxygen pressure in isolated perfused rat heart. This method monitors intracellular oxygenation in the whole heart and does not reflect oxygenation in a limited region. The deoxymyoglobin res...

  9. Stabilization of diastolic calcium signal via calcium pump regulation of complex local calcium releases and transient decay in a computational model of cardiac pacemaker cell with individual release channels.

    Directory of Open Access Journals (Sweden)

    Alexander V Maltsev

    2017-08-01

    Full Text Available Intracellular Local Ca releases (LCRs from sarcoplasmic reticulum (SR regulate cardiac pacemaker cell function by activation of electrogenic Na/Ca exchanger (NCX during diastole. Prior studies demonstrated the existence of powerful compensatory mechanisms of LCR regulation via a complex local cross-talk of Ca pump, release and NCX. One major obstacle to study these mechanisms is that LCR exhibit complex Ca release propagation patterns (including merges and separations that have not been characterized. Here we developed new terminology, classification, and computer algorithms for automatic detection of numerically simulated LCRs and examined LCR regulation by SR Ca pumping rate (Pup that provides a major contribution to fight-or-flight response. In our simulations the faster SR Ca pumping accelerates action potential-induced Ca transient decay and quickly clears Ca under the cell membrane in diastole, preventing premature releases. Then the SR generates an earlier, more synchronized, and stronger diastolic LCR signal activating an earlier and larger inward NCX current. LCRs at higher Pup exhibit larger amplitudes and faster propagation with more collisions to each other. The LCRs overlap with Ca transient decay, causing an elevation of the average diastolic [Ca] nadir to ~200 nM (at Pup = 24 mM/s. Background Ca (in locations lacking LCRs quickly decays to resting Ca levels (<100 nM at high Pup, but remained elevated during slower decay at low Pup. Release propagation is facilitated at higher Pup by a larger LCR amplitude, whereas at low Pup by higher background Ca. While at low Pup LCRs show smaller amplitudes, their larger durations and sizes combined with longer transient decay stabilize integrals of diastolic Ca and NCX current signals. Thus, the local interplay of SR Ca pump and release channels regulates LCRs and Ca transient decay to insure fail-safe pacemaker cell operation within a wide range of rates.

  10. Endoplasmic Reticulum Stress and Associated ROS

    Directory of Open Access Journals (Sweden)

    Hafiz Maher Ali Zeeshan

    2016-03-01

    Full Text Available The endoplasmic reticulum (ER is a fascinating network of tubules through which secretory and transmembrane proteins enter unfolded and exit as either folded or misfolded proteins, after which they are directed either toward other organelles or to degradation, respectively. The ER redox environment dictates the fate of entering proteins, and the level of redox signaling mediators modulates the level of reactive oxygen species (ROS. Accumulating evidence suggests the interrelation of ER stress and ROS with redox signaling mediators such as protein disulfide isomerase (PDI-endoplasmic reticulum oxidoreductin (ERO-1, glutathione (GSH/glutathione disuphide (GSSG, NADPH oxidase 4 (Nox4, NADPH-P450 reductase (NPR, and calcium. Here, we reviewed persistent ER stress and protein misfolding-initiated ROS cascades and their significant roles in the pathogenesis of multiple human disorders, including neurodegenerative diseases, diabetes mellitus, atherosclerosis, inflammation, ischemia, and kidney and liver diseases.

  11. Endoplasmic reticulum stress causes EBV lytic replication

    OpenAIRE

    Taylor, Gwen Marie; Raghuwanshi, Sandeep K.; Rowe, David T.; Wadowsky, Robert M.; Rosendorff, Adam

    2011-01-01

    Endoplasmic reticulum (ER) stress triggers a homeostatic cellular response in mammalian cells to ensure efficient folding, sorting, and processing of client proteins. In lytic-permissive lymphoblastoid cell lines (LCLs), pulse exposure to the chemical ER-stress inducer thapsigargin (TG) followed by recovery resulted in the activation of the EBV immediate-early (BRLF1, BZLF1), early (BMRF1), and late (gp350) genes, gp350 surface expression, and virus release. The protein phosphatase 1 a (PP1a)...

  12. Cardiac muscle: a miracle of creation.

    Science.gov (United States)

    Seely, S

    1989-09-01

    The paper proposes that energy conversion in muscle is a two-step process, chemical energy being first converted into electrical energy which is then converted into mechanical work. The chemo-electrical transducers are, in effect, minute voltaic cells--more precisely calcium-magnesium cells--with the magnesium electrodes on myosin heads and the calcium electrodes on the C subunits of troponin molecules associated with actin filaments. These cells are established when, after the passage of an action potential, calcium ions are admitted to the sarcomere. In an energy-consuming process, calcium ions are bound to troponin molecules, the energy for the process being supplied by hydrolysis of adenosine triphosphate. The electro-mechanical transducer utilises the electrostatic field established between the oppositely charged electrodes of the voltaic cell. As the two are pulled towards each other, doing mechanical work, energy is supplied by the voltaic cells. In the course of this action, calcium ions go back into solution. The action ceases when, after the passage of an action potential, calcium ions are withdrawn into the sarcoplasmic reticulum.

  13. Location matters: the endoplasmic reticulum and protein trafficking in dendrites

    Directory of Open Access Journals (Sweden)

    Omar A Ramírez

    2011-01-01

    Full Text Available Neurons are highly polarized, but the trafficking mechanisms that operate in these cells and the topological organization of their secretory organelles are still poorly understood. Particularly incipient is our knowledge of the role of the neuronal endoplasmic reticulum. Here we review the current understanding of the endoplasmic reticulum in neurons, its structure, composition, dendritic distribution and dynamics. We also focus on the trafficking of proteins through the dendritic endoplasmic reticulum, emphasizing the relevance of transport, retention, assembly of multi-subunit protein complexes and export. We additionally discuss the roles of the dendritic endoplasmic reticulum in synaptic plasticity.

  14. Fish sarcoplasmic proteins as a high value marine material for wound dressing applications.

    Science.gov (United States)

    Vieira, Sara; Franco, Albina R; Fernandes, Emanuel M; Amorim, Sara; Ferreira, Helena; Pires, Ricardo A; Reis, Rui L; Martins, Albino; Neves, Nuno M

    2018-07-01

    Fish sarcoplasmic proteins (FSP) constitute around 25-30% of the total fish muscle protein. As the FSP are water soluble, FSP were isolated from fresh cod (Gadus morhua) by centrifugation. By SDS-PAGE, it was possible to determine the composition of FSP extracts (FSP-E). The FSP-E undergo denaturation at 44.12 ± 2.34° C, as characterized by differential scanning calorimetry thermograms (DSC). The secondary structure of FSP-E is mainly composed by α-helix structure, as determined by circular dichroism. The cytocompatibility of FSP-E, at concentrations ranging from 5 to 20 mg/mL, was investigated. Concentrations lower than 10 mg/mL have no cytotoxicity cultures of fibroblasts over 72 h. Further on, FSP membranes (FSP-M) were produced by spin coating to evaluate its properties. FSP-M shown having uniform surface as analyzed by Scanning Electron Microscopy (SEM). The relative amount of α-helix structures is higher when compared with the FSP-E. The FSP-M have higher temperature stability than the FSP-E, since they presented a denaturation temperature of 58.88 ± 3.36° C, according to the DSC analysis. FSP-M shown distinctive mechanical properties, with a stiffness of 16.57 ± 3.95 MPa and a yield strength of 23.85 ± 5.97 MPa. Human lung fibroblasts cell lines (MRC-5) were cultured in direct contact with FSP-M, demonstrating its cytocompatibility for 48 h. Based on these results, FSP can be considered a potential biomaterial recovered from nature, for wound dressing applications. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Endoplasmic reticulum stress and diabetic retinopathy

    Directory of Open Access Journals (Sweden)

    Toshiyuki Oshitari

    2008-02-01

    Full Text Available Toshiyuki Oshitari1,2, Natsuyo Hata1, Shuichi Yamamoto11Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Chiba City, Chiba, Japan; 2Department of Ophthalmology, Kimitsu Central Hospital, Kisarazu City, Chiba, JapanAbstract: Endoplasmic reticulum (ER stress is involved in the pathogenesis of several diseases including Alzheimer disease and Parkinson disease. Many recent studies have shown that ER stress is related to the pathogenesis of diabetes mellitus, and with the death of pancreatic β-cells, insulin resistance, and the death of the vascular cells in the retina. Diabetic retinopathy is a major complication of diabetes and results in death of both neural and vascular cells. Because the death of the neurons directly affects visual function, the precise mechanism causing the death of neurons in early diabetic retinopathy must be determined. The ideal therapy for preventing the onset and the progression of diabetic retinopathy would be to treat the factors involved with both the vascular and neuronal abnormalities in diabetic retinopathy. In this review, we present evidence that ER stress is involved in the death of both retinal neurons and vascular cells in diabetic eyes, and thus reducing or blocking ER stress may be a potential therapy for preventing the onset and the progression of diabetic retinopathy.Keywords: endoplasmic reticulum stress, diabetic retinopathy, vascular cell death, neuronal cell death

  16. Endoplasmic reticulum involvement in yeast cell death

    International Nuclear Information System (INIS)

    Nicanor Austriaco, O.

    2012-01-01

    Yeast cells undergo programed cell death (PCD) with characteristic markers associated with apoptosis in mammalian cells including chromatin breakage, nuclear fragmentation, reactive oxygen species generation, and metacaspase activation. Though significant research has focused on mitochondrial involvement in this phenomenon, more recent work with both Saccharomyces cerevisiae and Schizosaccharomyces pombe has also implicated the endoplasmic reticulum (ER) in yeast PCD. This minireview provides an overview of ER stress-associated cell death (ER-SAD) in yeast. It begins with a description of ER structure and function in yeast before moving to a discussion of ER-SAD in both mammalian and yeast cells. Three examples of yeast cell death associated with the ER will be highlighted here including inositol starvation, lipid toxicity, and the inhibition of N-glycosylation. It closes by suggesting ways to further examine the involvement of the ER in yeast cell death.

  17. Endoplasmic Reticulum-Plasma Membrane Contact Sites.

    Science.gov (United States)

    Saheki, Yasunori; De Camilli, Pietro

    2017-06-20

    The endoplasmic reticulum (ER) has a broad localization throughout the cell and forms direct physical contacts with all other classes of membranous organelles, including the plasma membrane (PM). A number of protein tethers that mediate these contacts have been identified, and study of these protein tethers has revealed a multiplicity of roles in cell physiology, including regulation of intracellular Ca 2+ dynamics and signaling as well as control of lipid traffic and homeostasis. In this review, we discuss the cross talk between the ER and the PM mediated by direct contacts. We review factors that tether the two membranes, their properties, and their dynamics in response to the functional state of the cell. We focus in particular on the role of ER-PM contacts in nonvesicular lipid transport between the two bilayers mediated by lipid transfer proteins.

  18. Endoplasmic reticulum: ER stress regulates mitochondrial bioenergetics

    Science.gov (United States)

    Bravo, Roberto; Gutierrez, Tomás; Paredes, Felipe; Gatica, Damián; Rodriguez, Andrea E.; Pedrozo, Zully; Chiong, Mario; Parra, Valentina; Quest, Andrew F.G.; Rothermel, Beverly A.; Lavandero, Sergio

    2014-01-01

    Endoplasmic reticulum (ER) stress activates an adaptive unfolded protein response (UPR) that facilitates cellular repair, however, under prolonged ER stress, the UPR can ultimately trigger apoptosis thereby terminating damaged cells. The molecular mechanisms responsible for execution of the cell death program are relatively well characterized, but the metabolic events taking place during the adaptive phase of ER stress remain largely undefined. Here we discuss emerging evidence regarding the metabolic changes that occur during the onset of ER stress and how ER influences mitochondrial function through mechanisms involving calcium transfer, thereby facilitating cellular adaptation. Finally, we highlight how dysregulation of ER–mitochondrial calcium homeostasis during prolonged ER stress is emerging as a novel mechanism implicated in the onset of metabolic disorders. PMID:22064245

  19. Endoplasmic Reticulum (ER Stress and Endocrine Disorders

    Directory of Open Access Journals (Sweden)

    Daisuke Ariyasu

    2017-02-01

    Full Text Available The endoplasmic reticulum (ER is the organelle where secretory and membrane proteins are synthesized and folded. Unfolded proteins that are retained within the ER can cause ER stress. Eukaryotic cells have a defense system called the “unfolded protein response” (UPR, which protects cells from ER stress. Cells undergo apoptosis when ER stress exceeds the capacity of the UPR, which has been revealed to cause human diseases. Although neurodegenerative diseases are well-known ER stress-related diseases, it has been discovered that endocrine diseases are also related to ER stress. In this review, we focus on ER stress-related human endocrine disorders. In addition to diabetes mellitus, which is well characterized, several relatively rare genetic disorders such as familial neurohypophyseal diabetes insipidus (FNDI, Wolfram syndrome, and isolated growth hormone deficiency type II (IGHD2 are discussed in this article.

  20. Endoplasmic Reticulum (ER) Stress and Endocrine Disorders

    Science.gov (United States)

    Ariyasu, Daisuke; Yoshida, Hiderou; Hasegawa, Yukihiro

    2017-01-01

    The endoplasmic reticulum (ER) is the organelle where secretory and membrane proteins are synthesized and folded. Unfolded proteins that are retained within the ER can cause ER stress. Eukaryotic cells have a defense system called the “unfolded protein response” (UPR), which protects cells from ER stress. Cells undergo apoptosis when ER stress exceeds the capacity of the UPR, which has been revealed to cause human diseases. Although neurodegenerative diseases are well-known ER stress-related diseases, it has been discovered that endocrine diseases are also related to ER stress. In this review, we focus on ER stress-related human endocrine disorders. In addition to diabetes mellitus, which is well characterized, several relatively rare genetic disorders such as familial neurohypophyseal diabetes insipidus (FNDI), Wolfram syndrome, and isolated growth hormone deficiency type II (IGHD2) are discussed in this article. PMID:28208663

  1. Cardiac arrest

    Science.gov (United States)

    ... magnesium. These minerals help your heart's electrical system work. Abnormally high or low levels can cause cardiac arrest. Severe physical stress. Anything that causes a severe stress on your ...

  2. Cardiac Ochronosis

    Science.gov (United States)

    Erek, Ersin; Casselman, Filip P.A.; Vanermen, Hugo

    2004-01-01

    We report the case of 67-year-old woman who underwent aortic valve replacement and mitral valve repair due to ochronotic valvular disease (alkaptonuria), which was diagnosed incidentally during cardiac surgery. PMID:15745303

  3. Cardiac catheterization

    Science.gov (United States)

    ... tests. However, it is very safe when done by an experienced team. The risks include: Cardiac tamponade Heart attack Injury to a coronary artery Irregular heartbeat Low blood pressure Reaction to the contrast dye Stroke Possible complications ...

  4. Data supporting characterization of CLIC1, CLIC4, CLIC5 and DmCLIC antibodies and localization of CLICs in endoplasmic reticulum of cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Devasena Ponnalagu

    2016-06-01

    Full Text Available Chloride intracellular channel (CLICs proteins show 60–70% sequence identity to each other, and exclusively localize to the intracellular organelle membranes and cytosol. In support of our recent publication, “Molecular identity of cardiac mitochondrial chloride intracellular channel proteins” (Ponnalagu et al., 2016 [1], it was important to characterize the specificity of different CLIC paralogs/ortholog (CLIC1, CLIC4, CLIC5 and DmCLIC antibodies used to decipher their localization in cardiac cells. In addition, localization of CLICs in the other organelles such as endoplasmic reticulum (ER of cardiomyocytes was established. This article also provides data on the different primers used to show the relative abundance of CLIC paralogs in cardiac tissue and the specificity of the various CLIC antibodies used. We demonstrate that the predominant CLICs in the heart, namely CLIC1, CLIC4 and CLIC5, show differential distribution in endoplasmic reticulum. CLIC1 and CLIC4 both show co-localization to the endoplasmic reticulum whereas CLIC5 does not.

  5. Nuclear cardiac

    International Nuclear Information System (INIS)

    Slutsky, R.; Ashburn, W.L.

    1982-01-01

    The relationship between nuclear medicine and cardiology has continued to produce a surfeit of interesting, illuminating, and important reports involving the analysis of cardiac function, perfusion, and metabolism. To simplify the presentation, this review is broken down into three major subheadings: analysis of myocardial perfusion; imaging of the recent myocardial infarction; and the evaluation of myocardial function. There appears to be an increasingly important relationship between cardiology, particularly cardiac physiology, and nuclear imaging techniques

  6. Regulation of endoplasmic reticulum turnover by selective autophagy

    NARCIS (Netherlands)

    Khaminets, Aliaksandr; Heinrich, Theresa; Mari, Muriel; Grumati, Paolo; Huebner, Antje K; Akutsu, Masato; Liebmann, Lutz; Stolz, Alexandra; Nietzsche, Sandor; Koch, Nicole; Mauthe, Mario; Katona, Istvan; Qualmann, Britta; Weis, Joachim; Reggiori, Fulvio; Kurth, Ingo; Hübner, Christian A; Dikic, Ivan

    2015-01-01

    The endoplasmic reticulum (ER) is the largest intracellular endomembrane system, enabling protein and lipid synthesis, ion homeostasis, quality control of newly synthesized proteins and organelle communication. Constant ER turnover and modulation is needed to meet different cellular requirements and

  7. Regulation of endoplasmic reticulum turnover by selective autophagy

    NARCIS (Netherlands)

    Khaminets, Aliaksandr; Heinrich, Theresa; Mari, Muriel; Grumati, Paolo; Huebner, Antje K.; Akutsu, Masato; Liebmann, Lutz; Stolz, Alexandra; Nietzsche, Sandor; Koch, Nicole; Mauthe, Mario; Katona, Istvan; Qualmann, Britta; Weis, Joachim; Reggiori, Fulvio; Kurth, Ingo; Huebner, Christian A.; Dikic, Ivan

    2015-01-01

    The endoplasmic reticulum (ER) is the largest intracellular endomembrane system, enabling protein and lipid synthesis, ion homeostasis, quality control of newly synthesized proteins and organelle communication(1). Constant ER turnover and modulation is needed to meet different cellular requirements

  8. Cardiac CT

    International Nuclear Information System (INIS)

    Dewey, Marc

    2011-01-01

    Computed tomography of the heart has become a highly accurate diagnostic modality that is attracting increasing attention. This extensively illustrated book aims to assist the reader in integrating cardiac CT into daily clinical practice, while also reviewing its current technical status and applications. Clear guidance is provided on the performance and interpretation of imaging using the latest technology, which offers greater coverage, better spatial resolution, and faster imaging. The specific features of scanners from all four main vendors, including those that have only recently become available, are presented. Among the wide range of applications and issues to be discussed are coronary artery bypass grafts, stents, plaques, and anomalies, cardiac valves, congenital and acquired heart disease, and radiation exposure. Upcoming clinical uses of cardiac CT, such as plaque imaging and functional assessment, are also explored. (orig.)

  9. Cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Dewey, Marc [Charite - Universitaetsmedizin Berlin (Germany). Inst. fuer Radiologie

    2011-07-01

    Computed tomography of the heart has become a highly accurate diagnostic modality that is attracting increasing attention. This extensively illustrated book aims to assist the reader in integrating cardiac CT into daily clinical practice, while also reviewing its current technical status and applications. Clear guidance is provided on the performance and interpretation of imaging using the latest technology, which offers greater coverage, better spatial resolution, and faster imaging. The specific features of scanners from all four main vendors, including those that have only recently become available, are presented. Among the wide range of applications and issues to be discussed are coronary artery bypass grafts, stents, plaques, and anomalies, cardiac valves, congenital and acquired heart disease, and radiation exposure. Upcoming clinical uses of cardiac CT, such as plaque imaging and functional assessment, are also explored. (orig.)

  10. Cardiac echinococcosis

    Directory of Open Access Journals (Sweden)

    Ivanović-Krstić Branislava A.

    2002-01-01

    Full Text Available Cardiac hydatid disease is rare. We report on an uncommon hydatid cyst localized in the right ventricular wall, right atrial wall tricuspid valve left atrium and pericard. A 33-year-old woman was treated for cough, fever and chest pain. Cardiac echocardiograpic examination revealed a round tumor (5.8 x 4 cm in the right ventricular free wall and two smaller cysts behind that tumor. There were cysts in right atrial wall and tricuspidal valve as well. Serologic tests for hydatidosis were positive. Computed tomography finding was consistent with diagnosis of hydatid cyst in lungs and right hylar part. Surgical treatment was rejected due to great risk of cardiac perforation. Medical treatment with albendazole was unsuccessful and the patient died due to systemic hydatid involvement of the lungs, liver and central nervous system.

  11. Endoplasmic Reticulum Stress in Reproductive Function

    Directory of Open Access Journals (Sweden)

    Kang-sheng LIU

    2016-09-01

    Full Text Available Normal folding requires that unique conditions should be maintained within the endoplasmic reticulum (ER lumen, and nascent proteins are initially bound to Ca2+dependent chaperone proteins. Proteins synthesized in the ER are properly folded with the assistance of ER chaperones. misfolded proteins are disposed by ER-associated protein degradation. Accumulation of misfolded proteins in the ER triggers an adaptive ER stress response, which leads to activation of the unfolded protein response (UPR, a conserved pathway that transmits signals to restore homeostasis or eliminate the irreparably damaged cells. It has been shown that ER stress involves in pathophysiological development of many diseases, including neurological diseases. However, nowadays, a few studies have begun to focus on the possibility that the accumulation of misfolded proteins can also contribute to reproductive diseases. In this article, we mainly introduced the involvement of ER stress response in preimplantation embryos, placental development, intrauterine growth restriction (IUGR and testicular germ cells so as to provide important insights for the molecular mechanisms of ER stress-induced apoptosis in reproductive diseases.

  12. Endoplasmic reticulum proteostasis impairment in aging.

    Science.gov (United States)

    Martínez, Gabriela; Duran-Aniotz, Claudia; Cabral-Miranda, Felipe; Vivar, Juan P; Hetz, Claudio

    2017-08-01

    Perturbed neuronal proteostasis is a salient feature shared by both aging and protein misfolding disorders. The proteostasis network controls the health of the proteome by integrating pathways involved in protein synthesis, folding, trafficking, secretion, and their degradation. A reduction in the buffering capacity of the proteostasis network during aging may increase the risk to undergo neurodegeneration by enhancing the accumulation of misfolded proteins. As almost one-third of the proteome is synthetized at the endoplasmic reticulum (ER), maintenance of its proper function is fundamental to sustain neuronal function. In fact, ER stress is a common feature of most neurodegenerative diseases. The unfolded protein response (UPR) operates as central player to maintain ER homeostasis or the induction of cell death of chronically damaged cells. Here, we discuss recent evidence placing ER stress as a driver of brain aging, and the emerging impact of neuronal UPR in controlling global proteostasis at the whole organismal level. Finally, we discuss possible therapeutic interventions to improve proteostasis and prevent pathological brain aging. © 2017 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  13. Endoplasmic reticulum stress causes EBV lytic replication.

    Science.gov (United States)

    Taylor, Gwen Marie; Raghuwanshi, Sandeep K; Rowe, David T; Wadowsky, Robert M; Rosendorff, Adam

    2011-11-17

    Endoplasmic reticulum (ER) stress triggers a homeostatic cellular response in mammalian cells to ensure efficient folding, sorting, and processing of client proteins. In lytic-permissive lymphoblastoid cell lines (LCLs), pulse exposure to the chemical ER-stress inducer thapsigargin (TG) followed by recovery resulted in the activation of the EBV immediate-early (BRLF1, BZLF1), early (BMRF1), and late (gp350) genes, gp350 surface expression, and virus release. The protein phosphatase 1 a (PP1a)-specific phosphatase inhibitor Salubrinal (SAL) synergized with TG to induce EBV lytic genes; however, TG treatment alone was sufficient to activate EBV lytic replication. SAL showed ER-stress-dependent and -independent antiviral effects, preventing virus release in human LCLs and abrogating gp350 expression in 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated B95-8 cells. TG resulted in sustained BCL6 but not BLIMP1 or CD138 expression, which is consistent with maintenance of a germinal center B-cell, rather than plasma-cell, phenotype. Microarray analysis identified candidate genes governing lytic replication in LCLs undergoing ER stress.

  14. A novel heterozygous mutation of the WFS1 gene leading to constitutive endoplasmic reticulum stress is the cause of Wolfram syndrome.

    Science.gov (United States)

    Morikawa, Shuntaro; Tajima, Toshihiro; Nakamura, Akie; Ishizu, Katsura; Ariga, Tadashi

    2017-12-01

    Wolfram syndrome (WS) is a disorder characterized by the association of insulin-dependent diabetes mellitus (DM), diabetes insipidus, deafness, and optic nerve atrophy. WS is caused by WFS1 mutations encoding WFS1 protein expressed in endoplasmic reticulum (ER). During ER protein synthesis, misfolded and unfolded proteins accumulate, known as "ER stress". This is attenuated by the unfolded protein response (UPR), which recovers and maintains ER functions. Because WFS1 is a UPR component, mutant WFS1 might cause unresolvable ER stress conditions and cell apoptosis, the major causes underlying WS symptoms. We encountered an 11-month-old Japanese female WS patient with insulin-dependent DM, congenital cataract and severe bilateral hearing loss. Analyze the WFS1 and functional consequence of the patient WFS1 in vitro. The patient WFS1 contained a heterozygous 4 amino acid in-frame deletion (p.N325_I328del). Her mutant WFS1 increased GRP78 and ATF6α promoter activities in the absence of thapsigargin, indicating constitutive ER stress and nuclear factor of activated T-cell reporter activity, reflecting elevated cytosolic Ca 2+ signals. Mutant transfection into cells reduced mRNA expression levels of sarcoplasmic/endoplasmic reticulum Ca 2+ transport ATPase 2b (SERCA2b) compared with wild type. Because SERCA2b is required for ER and cytoplasmic Ca 2+ homeostasis, decreased SERCA2b expression might affect ER Ca 2+ efflux, causing cell apoptosis. A novel heterozygous mutation of WFS1 induced constitutive ER stress through ATF6α activation and ER Ca 2+ efflux, resulting in cell apoptosis. These results provide new insights into the roles of WFS1 in UPR and mechanism of monogenic DM. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. [Cardiac cachexia].

    Science.gov (United States)

    Miján, Alberto; Martín, Elvira; de Mateo, Beatriz

    2006-05-01

    Chronic heart failure (CHF), especially affecting the right heart, frequently leads to malnutrition. If the latter is severe and is combined to other factors, it may lead to cardiac cachexia. This one is associated to increased mortality and lower survival of patients suffering from it. The causes of cardiac cachexia are diverse, generally associated to maintenance of a negative energy balance, with increasing evidence of its multifactorial origin. Neurohumoral, inflammatory, immunological, and metabolic factors, among others, are superimposed in the patient with CHF, leading to involvement and deterioration of several organs and systems, since this condition affects both lean (or active cellular) mass and adipose and bone tissue osteoporosis. Among all, the most pronounced deterioration may be seen at skeletal muscle tissue, at both structural and functional levels, the heart not being spared. As for treatment, it should be based on available scientific evidence. Assessment of nutritional status of any patient with CHF is a must, with the requirement of nutritional intervention in case of malnutrition. In this situation, especially if accompanied by cardiac cachexia, it is required to modify energy intake and oral diet quality, and to consider the indication of specific complementary or alternative artificial nutrition. Besides, the causal relationship of the beneficial role of moderate physical exertion is increasing, as well as modulation of metabolic and inflammatory impairments observed in cardiac cachexia with several drugs, leading to a favorable functional and structural response in CHF patients.

  16. Cardiac Pacemakers

    International Nuclear Information System (INIS)

    Fiandra, O.; Espasandin, W.; Fiandra, H.

    1984-01-01

    A complete survey of physiological biophysical,clinical and engineering aspects of cardiac facing,including the history and an assessment of possible future developments.Among the topics studied are: pacemakers, energy search, heart stimulating with pacemakers ,mathematical aspects of the electric cardio stimulation chronic, pacemaker implants,proceeding,treatment and control

  17. Inhibition of the Unfolded Protein Response Mechanism Prevents Cardiac Fibrosis.

    Directory of Open Access Journals (Sweden)

    Jody Groenendyk

    Full Text Available Cardiac fibrosis attributed to excessive deposition of extracellular matrix proteins is a major cause of heart failure and death. Cardiac fibrosis is extremely difficult and challenging to treat in a clinical setting due to lack of understanding of molecular mechanisms leading to cardiac fibrosis and effective anti-fibrotic therapies. The objective in this study was to examine whether unfolded protein response (UPR pathway mediates cardiac fibrosis and whether a pharmacological intervention to modulate UPR can prevent cardiac fibrosis and preserve heart function.We demonstrate here that the mechanism leading to development of fibrosis in a mouse with increased expression of calreticulin, a model of heart failure, stems from impairment of endoplasmic reticulum (ER homeostasis, transient activation of the unfolded protein response (UPR pathway and stimulation of the TGFβ1/Smad2/3 signaling pathway. Remarkably, sustained pharmacologic inhibition of the UPR pathway by tauroursodeoxycholic acid (TUDCA is sufficient to prevent cardiac fibrosis, and improved exercise tolerance.We show that the mechanism leading to development of fibrosis in a mouse model of heart failure stems from transient activation of UPR pathway leading to persistent remodelling of cardiac tissue. Blocking the activation of the transiently activated UPR pathway by TUDCA prevented cardiac fibrosis, and improved prognosis. These findings offer a window for additional interventions that can preserve heart function.

  18. Temperature dependence of the kinetics of isometric myocardium relaxation

    Energy Technology Data Exchange (ETDEWEB)

    Izakov, V.Ya.; Bykov, B.L.; Kimmelman, I.Ya.

    1981-11-01

    The dependence of the exponential decay constant expressing the isometric relaxation of the myocardium on temperature is investigated in animals with various specific contents of myocardial sarcoplasmic reticulum. Experiments were performed on cardiac ventricles and atria isolated from rabbits, frogs and turtles and electrically stimulated to produce maximal contraction at temperatures from 10 to 35 C. Arrhenius plots derived from the data are found to be linear in the myocardia of the rabbit and frog, with a greater activation energy for the relaxation found in the rabbit. The Arrhenius plot for the turtle, which has a sarcoplasmic reticulum content intermediate between those of the frog and rabbit, corresponds to two straight lines with different activation energies. Results thus support the hypothesis of two separate mechanisms of calcium removal, involving the sarcoplasmic reticulum and cellular membrane, in muscle relaxation.

  19. In Vitro Contracture Test Results and Anaesthetic Management of a Patient with Emery-Dreifuss Muscular Dystrophy for Cardiac Transplantation

    Directory of Open Access Journals (Sweden)

    Frank Schuster

    2012-01-01

    Full Text Available Emery-Dreifuss muscular dystrophy (EDMD is a hereditary neuromuscular disorder characterized by slowly progressive muscle weakness, early contractures, and dilated cardiomyopathy. We reported an uneventful general anaesthesia using total intravenous anaesthesia (TIVA for cardiac transplantation in a 19-year-old woman suffering from EDMD. In vitro contracture test results of two pectoralis major muscle bundles of the patient suggest that exposition to triggering agents does not induce a pathological sarcoplasmic calcium release in the lamin A/C phenotype. However, due to the lack of evidence in the literature, we would recommend TIVA for patients with EDMD if general anaesthesia is required.

  20. Cardiac ablation

    Directory of Open Access Journals (Sweden)

    Kelly Ratheal

    2016-01-01

    Full Text Available Cardiac ablation is a procedure that uses either radiofrequency or cryothermal energy to destroy cells in the heart to terminate and/or prevent arrhythmias. The indications for cardiac catheter ablation include refractory, symptomatic arrhythmias, with more specific guidelines for atrial fibrillation in particular. The ablation procedure itself involves mapping the arrhythmia and destruction of the aberrant pathway in an effort to permanently prevent the arrhythmia. There are many types of arrhythmias, and they require individualized approaches to ablation based on their innately different electrical pathways. Ablation of arrhythmias, such as Wolff-Parkinson-White syndrome, AV nodal reentrant tachycardia, and atrial-fibrillation, is discussed in this review. Ablation has a high success rate overall and minimal complication rates, leading to improved quality of life in many patients.

  1. Proteomic study of muscle sarcoplasmic proteins using AUT-PAGE/SDS-PAGE as two-dimensional gel electrophoresis.

    Science.gov (United States)

    Picariello, Gianluca; De Martino, Alessandra; Mamone, Gianfranco; Ferranti, Pasquale; Addeo, Francesco; Faccia, Michele; Spagnamusso, Salvatore; Di Luccia, Aldo

    2006-03-20

    In the present study, an alternative procedure for two-dimensional (2D) electrophoretic analysis in proteomic investigation of the most represented basic muscle water-soluble proteins is suggested. Our method consists of Acetic acid-Urea-Triton polyacrylamide gel (AUT-PAGE) analysis in the first dimension and standard sodium dodecyl sulphate polyacrylamide gel (SDS-PAGE) in the second dimension. Although standard two-dimensional Immobilized pH Gradient-Sodium Dodecyl-Sulphate (2D IPG-SDS) gel electrophoresis has been successfully used to study these proteins, most of the water-soluble proteins are spread on the alkaline part of the 2D map and are poorly focused. Furthermore, the similarity in their molecular weights impairs resolution of the classical approach. The addition of Triton X-100, a non-ionic detergent, into the gel induces a differential electrophoretic mobility of proteins as a result of the formation of mixed micelles between the detergent and the hydrophobic moieties of polypeptides, separating basic proteins with a criterion similar to reversed phase chromatography based on their hydrophobicity. The acid pH induces positive net charges, increasing with the isoelectric point of proteins, thus allowing enhanced resolution in the separation. By using 2D AUT-PAGE/SDS electrophoresis approach to separate water-soluble proteins from fresh pork and from dry-cured products, we could spread proteins over a greater area, achieving a greater resolution than that obtained by IPG in the pH range 3-10 and 6-11. Sarcoplasmic proteins undergoing proteolysis during the ripening of products were identified by Matrix Assisted Laser Desorption/Ionization-Time of Flight (MALDI-ToF) mass spectrometry peptide mass fingerprinting in a easier and more effective way. Two-dimensional AUT-PAGE/SDS electrophoresis has allowed to simplify separation of sarcoplasmic protein mixtures making this technique suitable in the defining of quality of dry-cured pork products by immediate

  2. Plasma membrane—endoplasmic reticulum contact sites regulate phosphatidylcholine synthesis

    NARCIS (Netherlands)

    Tavassoli, S.; Chao, J.T.; Young, B.P.; Cox, R.C.; Prinz, W.A.; de Kroon, A.I.P.M.; Loewen, C.I.R.

    2013-01-01

    Synthesis of phospholipids, sterols and sphingolipids is thought to occur at contact sites between the endoplasmic reticulum (ER) and other organelles because many lipid-synthesizing enzymes are enriched in these contacts. In only a few cases have the enzymes been localized to contacts in vivo and

  3. Analysis of endoplasmic reticulum of tobacco cells using confocal microscopy

    Czech Academy of Sciences Publication Activity Database

    Radochová, Barbora; Janáček, Jiří; Schwarzerová, K.; Demjénová, E.; Tomori, Z.; Karen, Petr; Kubínová, Lucie

    2005-01-01

    Roč. 24, č. 11 (2005), s. 181-185 ISSN 1580-3139 R&D Projects: GA AV ČR(CZ) KJB6011309 Institutional research plan: CEZ:AV0Z50110509 Keywords : confocal microscopy * endoplasmic reticulum * image analysis Subject RIV: EA - Cell Biology

  4. Endoplasmic reticulum-dependent redox reactions control endoplasmic reticulum-associated degradation and pathogen entry.

    Science.gov (United States)

    Walczak, Christopher P; Bernardi, Kaleena M; Tsai, Billy

    2012-04-15

    Protein misfolding within the endoplasmic reticulum (ER) is managed by an ER quality control system that retro-translocates aberrant proteins into the cytosol for proteasomal destruction. This process, known as ER-associated degradation, utilizes the action of ER redox enzymes to accommodate the disulfide-bonded nature of misfolded proteins. Strikingly, various pathogenic viruses and toxins co-opt these redox components to reach the cytosol during entry. These redox factors thus regulate critical cellular homeostasis and host-pathogen interactions. Recent studies identify specific members of the protein disulfide isomerase (PDI) family, which use their chaperone and catalytic activities, in engaging both misfolded ER proteins and pathogens. The precise molecular mechanism by which a dedicated PDI family member disrupts the disulfide bonds in the misfolded ER proteins and pathogens, as well as how they act to unfold these substrates to promote their ER-to-cytosol membrane transport, remain poorly characterized. How PDI family members distinguish folded versus misfolded ER substrates remains enigmatic. What physical characteristics surrounding a substrate's disulfide bond instruct PDI that it is mispaired or native? For the pathogens, as their disulfide bonds normally serve a critical role in providing physical support, what conformational changes experienced in the host enable their disulfide bonds to be disrupted? A combination of more rigorous biochemical and high-resolution structural studies should begin to address these questions.

  5. Cardiac pacemaker

    International Nuclear Information System (INIS)

    Kolenik, S.A.

    1976-01-01

    The construction of a cardiac pacemaker is described which is characterized by particularly small dimensions, small weight and long life duration. The weight is under 100g, the specific weight under 1.7. Mass inertia forces which occur through acceleration and retardation processes, thus remain below the threshold values, above which one would have to reckon with considerable damaging of the surrounding body tissue. The maintaining of small size and slight weight is achieved by using an oscillator on COSMOS basis, where by considerably lower energy consumption, amongst others the lifetimes of the batteries used - a lithium anode with thionyl chloride electrolyte - is extended to over 5 years. The reliability can be increased by the use of 2 or more batteries. The designed dimension are 20x60x60 mm 3 . (ORU/LH) [de

  6. Cardiac ventriculography

    International Nuclear Information System (INIS)

    Hillis, L.D.; Grossman, W.

    1986-01-01

    Cardiac ventriculography has been used extensively to define the anatomy of the ventricles and related structures in patients with congenital, valvular, coronary, and cardiomyopathic heart disease. Specifically, left ventriculography may provide valuable information about global and segmental left ventricular function, mitral valvular incompetence, and the presence, location, and severity of a number of other abnormalities, including ventricular septal defect and hypertrophic cardiomyopathy. As a result, it should be a routine part of catheterization in patients being evaluated for coronary artery disease, aortic or mitral valvular disease, unexplained left ventricular failure, or congenital heart disease. Similarly, right ventriculography may provide information about global and segmental right ventricular function and can be especially helpful in patients with congenital heart disease

  7. HDAC Inhibition Improves the Sarcoendoplasmic Reticulum Ca2+-ATPase Activity in Cardiac Myocytes.

    Science.gov (United States)

    Meraviglia, Viviana; Bocchi, Leonardo; Sacchetto, Roberta; Florio, Maria Cristina; Motta, Benedetta M; Corti, Corrado; Weichenberger, Christian X; Savi, Monia; D'Elia, Yuri; Rosato-Siri, Marcelo D; Suffredini, Silvia; Piubelli, Chiara; Pompilio, Giulio; Pramstaller, Peter P; Domingues, Francisco S; Stilli, Donatella; Rossini, Alessandra

    2018-01-31

    SERCA2a is the Ca 2+ ATPase playing the major contribution in cardiomyocyte (CM) calcium removal. Its activity can be regulated by both modulatory proteins and several post-translational modifications. The aim of the present work was to investigate whether the function of SERCA2 can be modulated by treating CMs with the histone deacetylase (HDAC) inhibitor suberanilohydroxamic acid (SAHA). The incubation with SAHA (2.5 µM, 90 min) of CMs isolated from rat adult hearts resulted in an increase of SERCA2 acetylation level and improved ATPase activity. This was associated with a significant improvement of calcium transient recovery time and cell contractility. Previous reports have identified K464 as an acetylation site in human SERCA2. Mutants were generated where K464 was substituted with glutamine (Q) or arginine (R), mimicking constitutive acetylation or deacetylation, respectively. The K464Q mutation ameliorated ATPase activity and calcium transient recovery time, thus indicating that constitutive K464 acetylation has a positive impact on human SERCA2a (hSERCA2a) function. In conclusion, SAHA induced deacetylation inhibition had a positive impact on CM calcium handling, that, at least in part, was due to improved SERCA2 activity. This observation can provide the basis for the development of novel pharmacological approaches to ameliorate SERCA2 efficiency.

  8. Inhibition of sarcoplasmic Ca2+-ATPase increases caffeine- and halothane-induced contractures in muscle bundles of malignant hyperthermia susceptible and healthy individuals

    Directory of Open Access Journals (Sweden)

    Roewer Norbert

    2005-06-01

    Full Text Available Abstract Background Malignant hyperthermia (MH is triggered by halogenated anaesthetics and depolarising muscle relaxants, leading to an uncontrolled hypermetabolic state of skeletal muscle. An uncontrolled sarcoplasmic Ca2+ release is mediated via the ryanodine receptor. A compensatory mechanism of increased sarcoplasmic Ca2+-ATPase activity was described in pigs and in transfected cell lines. We hypothesized that inhibition of Ca2+ reuptake via the sarcoplasmic Ca2+-ATPase (SERCA enhances halothane- and caffeine-induced muscle contractures in MH susceptible more than in non-susceptible skeletal muscle. Methods With informed consent, surplus muscle bundles of 7 MHS (susceptible, 7 MHE (equivocal and 16 MHN (non-susceptible classified patients were mounted to an isometric force transducer, electrically stimulated, preloaded and equilibrated. Following 15 min incubation with cyclopiazonic acid (CPA 25 μM, the European MH standard in-vitro-contracture test protocol with caffeine (0.5; 1; 1.5; 2; 3; 4 mM and halothane (0.11; 0.22; 0.44; 0.66 mM was performed. Data as median and quartiles; Friedman- and Wilcoxon-test for differences with and without CPA; p Results Initial length, weight, maximum twitch height, predrug resting tension and predrug twitch height of muscle bundles did not differ between groups. CPA increased halothane- and caffeine-induced contractures significantly. This increase was more pronounced in MHS and MHE than in MHN muscle bundles. Conclusion Inhibition of the SERCA activity by CPA enhances halothane- and caffeine-induced contractures especially in MHS and MHE skeletal muscle and may help for the diagnostic assignment of MH susceptibility. The status of SERCA activity may play a significant but so far unknown role in the genesis of malignant hyperthermia.

  9. Cardiac regeneration therapy: connections to cardiac physiology.

    Science.gov (United States)

    Takehara, Naofumi; Matsubara, Hiroaki

    2011-12-01

    Without heart transplantation, a large number of patients with failing hearts worldwide face poor outcomes. By means of cardiomyocyte regeneration, cardiac regeneration therapy is emerging with great promise as a means for restoring loss of cardiac function. However, the limited success of clinical trials using bone marrow-derived cells and myoblasts with heterogeneous constituents, transplanted at a wide range of cell doses, has led to disagreement on the efficacy of cell therapy. It is therefore essential to reevaluate the evidence for the efficacy of cell-based cardiac regeneration therapy, focusing on targets, materials, and methodologies. Meanwhile, the revolutionary innovation of cardiac regeneration therapy is sorely needed to help the millions of people who suffer heart failure from acquired loss of cardiomyocytes. Cardiac regeneration has been used only in limited species or as a developing process in the rodent heart; now, the possibility of cardiomyocyte turnover in the human heart is being revisited. In the pursuit of this concept, the use of cardiac stem/progenitor stem cells in the cardiac niche must be focused to usher in a second era of cardiac regeneration therapy for the severely injured heart. In addition, tissue engineering and cellular reprogramming will advance the next era of treatment that will enable current cell-based therapy to progress to "real" cardiac regeneration therapy. Although many barriers remain, the prevention of refractory heart failure through cardiac regeneration is now becoming a realistic possibility.

  10. Osteochondritis dissecans (OCD), an endoplasmic reticulum storage disease?

    DEFF Research Database (Denmark)

    Skagen, Peter Storgaard; Horn, T; Kruse, H A

    2011-01-01

    Osteochondritis dissecans (OCD) fragments, cartilage and blood from four patients were used for morphological and molecular analysis. Controls included articular cartilage and blood samples from healthy individuals. Light microscopy and transmission electron microscopy (TEM) showed abnormalities...... in chondrocytes and extracellular matrix of cartilage from OCD patients. Abnormal type II collagen heterofibrils in "bundles" and chondrocytes with abnormal accumulation of matrix proteins in distended rough endoplasmic reticulum were typical findings. Further, Von Kossa staining and TEM showed empty lacunae...... polymorphism was found within the COL2A1 gene for one patient. We suggest that OCD lesions are caused by an alteration in chondrocyte matrix synthesis causing an endoplasmic reticulum storage disease phenotype, which disturbs or abrupts endochondral ossification....

  11. Prediction of endoplasmic reticulum resident proteins using fragmented amino acid composition and support vector machine

    Directory of Open Access Journals (Sweden)

    Ravindra Kumar

    2017-09-01

    Full Text Available Background The endoplasmic reticulum plays an important role in many cellular processes, which includes protein synthesis, folding and post-translational processing of newly synthesized proteins. It is also the site for quality control of misfolded proteins and entry point of extracellular proteins to the secretory pathway. Hence at any given point of time, endoplasmic reticulum contains two different cohorts of proteins, (i proteins involved in endoplasmic reticulum-specific function, which reside in the lumen of the endoplasmic reticulum, called as endoplasmic reticulum resident proteins and (ii proteins which are in process of moving to the extracellular space. Thus, endoplasmic reticulum resident proteins must somehow be distinguished from newly synthesized secretory proteins, which pass through the endoplasmic reticulum on their way out of the cell. Approximately only 50% of the proteins used in this study as training data had endoplasmic reticulum retention signal, which shows that these signals are not essentially present in all endoplasmic reticulum resident proteins. This also strongly indicates the role of additional factors in retention of endoplasmic reticulum-specific proteins inside the endoplasmic reticulum. Methods This is a support vector machine based method, where we had used different forms of protein features as inputs for support vector machine to develop the prediction models. During training leave-one-out approach of cross-validation was used. Maximum performance was obtained with a combination of amino acid compositions of different part of proteins. Results In this study, we have reported a novel support vector machine based method for predicting endoplasmic reticulum resident proteins, named as ERPred. During training we achieved a maximum accuracy of 81.42% with leave-one-out approach of cross-validation. When evaluated on independent dataset, ERPred did prediction with sensitivity of 72.31% and specificity of 83

  12. Hypercholesterolemia aggravates myocardial ischemia reperfusion injury via activating endoplasmic reticulum stress-mediated apoptosis.

    Science.gov (United States)

    Wu, Nan; Zhang, Xiaowen; Jia, Pengyu; Jia, Dalin

    2015-12-01

    The effect of hypercholesterolemia on myocardial ischemia reperfusion injury (MIRI) is in controversy and the underlying mechanism is still not well understood. In the present study, we firstly detected the effects of hypercholesterolemia on MIRI and the role of endoplasmic reticulum (ER) stress-mediated apoptosis pathway in this process. The infarct size was determined by TTC staining, and apoptosis was measured by the TUNEL method. The marker proteins of ER stress response and ER stress-mediated apoptosis pathway were detected by Western blot. The results showed that high cholesterol diet-induced hypercholesterolemia significantly increased the myocardial infarct size, the release of myocardium enzyme and the ratio of apoptosis, but did not affect the recovery of cardiac function. Moreover, hypercholesterolemia also remarkably up-regulated the expressions of ER stress markers (glucose-regulated protein 78 and calreticulin) and critical molecules in ER stress-mediated apoptosis pathway (CHOP, caspase 12, phospho-JNK). In conclusion, our study demonstrated that hypercholesterolemia enhanced myocardial vulnerability/sensitivity to ischemia reperfusion injury involved in aggravation the ER stress and activation of ER stress-mediated apoptosis pathway and it gave us a new insight into the underlying mechanisms associated with hypercholesterolemia-induced exaggerated MIRI and also provided a novel target for preventing MIRI in the presence of hypercholesterolemia. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. A novel protein involved in heart development in Ambystoma mexicanum is localized in endoplasmic reticulum.

    Science.gov (United States)

    Jia, P; Zhang, C; Huang, X P; Poda, M; Akbas, F; Lemanski, S L; Erginel-Unaltuna, N; Lemanski, L F

    2008-11-01

    The discovery of the naturally occurring cardiac non-function (c) animal strain in Ambystoma mexicanum (axolotl) provides a valuable animal model to study cardiomyocyte differentiation. In homozygous mutant animals (c/c), rhythmic contractions of the embryonic heart are absent due to a lack of organized myofibrils. We have previously cloned a partial sequence of a peptide cDNA (N1) from an anterior-endoderm-conditioned-medium RNA library that had been shown to be able to rescue the mutant phenotype. In the current studies we have fully cloned the N1 full length cDNA sequence from the library. N1 protein has been detected in both adult heart and skeletal muscle but not in any other adult tissues. GFP-tagged expression of the N1 protein has revealed localization of the N1 protein in the endoplasmic reticulum (ER). Results from in situ hybridization experiments have confirmed the dramatic decrease of expression of N1 mRNA in mutant (c/c) embryos indicating that the N1 gene is involved in heart development.

  14. β-Arrestin2 Improves Post-Myocardial Infarction Heart Failure via Sarco(endo)plasmic Reticulum Ca2+-ATPase-Dependent Positive Inotropy in Cardiomyocytes.

    Science.gov (United States)

    McCrink, Katie A; Maning, Jennifer; Vu, Angela; Jafferjee, Malika; Marrero, Christine; Brill, Ava; Bathgate-Siryk, Ashley; Dabul, Samalia; Koch, Walter J; Lymperopoulos, Anastasios

    2017-11-01

    Heart failure is the leading cause of death in the Western world, and new and innovative treatments are needed. The GPCR (G protein-coupled receptor) adapter proteins βarr (β-arrestin)-1 and βarr-2 are functionally distinct in the heart. βarr1 is cardiotoxic, decreasing contractility by opposing β 1 AR (adrenergic receptor) signaling and promoting apoptosis/inflammation post-myocardial infarction (MI). Conversely, βarr2 inhibits apoptosis/inflammation post-MI but its effects on cardiac function are not well understood. Herein, we sought to investigate whether βarr2 actually increases cardiac contractility. Via proteomic investigations in transgenic mouse hearts and in H9c2 rat cardiomyocytes, we have uncovered that βarr2 directly interacts with SERCA2a (sarco[endo]plasmic reticulum Ca 2+ -ATPase) in vivo and in vitro in a β 1 AR-dependent manner. This interaction causes acute SERCA2a SUMO (small ubiquitin-like modifier)-ylation, increasing SERCA2a activity and thus, cardiac contractility. βarr1 lacks this effect. Moreover, βarr2 does not desensitize β 1 AR cAMP-dependent procontractile signaling in cardiomyocytes, again contrary to βarr1. In vivo, post-MI heart failure mice overexpressing cardiac βarr2 have markedly improved cardiac function, apoptosis, inflammation, and adverse remodeling markers, as well as increased SERCA2a SUMOylation, levels, and activity, compared with control animals. Notably, βarr2 is capable of ameliorating cardiac function and remodeling post-MI despite not increasing cardiac βAR number or cAMP levels in vivo. In conclusion, enhancement of cardiac βarr2 levels/signaling via cardiac-specific gene transfer augments cardiac function safely, that is, while attenuating post-MI remodeling. Thus, cardiac βarr2 gene transfer might be a novel, safe positive inotropic therapy for both acute and chronic post-MI heart failure. © 2017 American Heart Association, Inc.

  15. Diffuse infiltrative cardiac tuberculosis

    International Nuclear Information System (INIS)

    Gulati, Gurpreet S; Kothari, Shyam S

    2011-01-01

    We present the cardiac magnetic resonance images of an unusual form of cardiac tuberculosis. Nodular masses in a sheet-like distribution were seen to infiltrate the outer myocardium and pericardium along most of the cardiac chambers. The lesions showed significant resolution on antitubercular therapy

  16. Acrolein Induces Endoplasmic Reticulum Stress and Causes Airspace Enlargement

    Science.gov (United States)

    Hanaoka, Masayuki; Natarajan, Ramesh; Kraskauskas, Donatas; Voelkel, Norbert F.

    2012-01-01

    Background Given the relative abundance and toxic potential of acrolein in inhaled cigarette smoke, it is surprising how little is known about the pulmonary and systemic effects of acrolein. Here we test the hypothesis whether systemic administration of acrolein could cause endoplasmic reticulum (ER) stress, and lung cell apoptosis, leading to the enlargement of the alveolar air spaces in rats. Methods Acute and chronic effects of intraperitoneally administered acrolein were tested. Mean alveolar airspace area was measured by using light microscopy and imaging system software. TUNEL staining and immunohistochemistry (IHC) for active caspase 3 and Western blot analysis for active caspase 3, and caspase 12 were performed to detect apoptosis. The ER-stress related gene expression in the lungs was determined by Quantitative real-time PCR analysis. Acrolein-protein adducts in the lung tissue were detected by IHC. Results Acute administration of acrolein caused a significant elevation of activated caspase 3, upregulation of VEGF expression and induced ER stress proteins in the lung tissue. The chronic administration of acrolein in rats led to emphysematous lung tissue remodeling. TUNEL staining and IHC for cleaved caspase 3 showed a large number of apoptotic septal cells in the acrolein-treated rat lungs. Chronic acrolein administration cause the endoplasmic reticulum stress response manifested by significant upregulation of ATF4, CHOP and GADd34 expression. In smokers with COPD there was a considerable accumulation of acrolein-protein adducts in the inflammatory, airway and vascular cells. Conclusions Systemic administration of acrolein causes endoplasmic reticulum stress response, lung cell apoptosis, and chronic administration leads to the enlargement of the alveolar air spaces and emphysema in rats. The substantial accumulation of acrolein-protein adducts in the lungs of COPD patients suggest a role of acrolein in the pathogenesis of emphysema. PMID:22675432

  17. Met receptor inhibitor SU11274 localizes in the endoplasmic reticulum.

    Science.gov (United States)

    Wiest, Edwin J; Smith, Heather Jensen; Hollingsworth, Michael A

    2018-07-02

    We discovered that SU11274, a class I c-Met inhibitor, fluoresces when excited by 488 nm laser light and showed rapid specific accumulation in distinct subcellular compartments. Given that SU11274 reduces cancer cell viability, we exploited these newly identified spectral properties to determine SU11274 intracellular distribution and accumulation in human pancreatic cancer cells. The aim of the studies reported here was to identify organelle(s) to which SU11274 is trafficked. We conclude that SU11274 rapidly and predominantly accumulates in the endoplasmic reticulum. Copyright © 2018. Published by Elsevier Inc.

  18. The role of the endoplasmic reticulum stress response following cerebral ischemia.

    Science.gov (United States)

    Hadley, Gina; Neuhaus, Ain A; Couch, Yvonne; Beard, Daniel J; Adriaanse, Bryan A; Vekrellis, Kostas; DeLuca, Gabriele C; Papadakis, Michalis; Sutherland, Brad A; Buchan, Alastair M

    2018-06-01

    Background Cornu ammonis 3 (CA3) hippocampal neurons are resistant to global ischemia, whereas cornu ammonis (CA1) 1 neurons are vulnerable. Hamartin expression in CA3 neurons mediates this endogenous resistance via productive autophagy. Neurons lacking hamartin demonstrate exacerbated endoplasmic reticulum stress and increased cell death. We investigated endoplasmic reticulum stress responses in CA1 and CA3 regions following global cerebral ischemia, and whether pharmacological modulation of endoplasmic reticulum stress or autophagy altered neuronal viability . Methods In vivo: male Wistar rats underwent sham or 10 min of transient global cerebral ischemia. CA1 and CA3 areas were microdissected and endoplasmic reticulum stress protein expression quantified at 3 h and 12 h of reperfusion. In vitro: primary neuronal cultures (E18 Wistar rat embryos) were exposed to 2 h of oxygen and glucose deprivation or normoxia in the presence of an endoplasmic reticulum stress inducer (thapsigargin or tunicamycin), an endoplasmic reticulum stress inhibitor (salubrinal or 4-phenylbutyric acid), an autophagy inducer ([4'-(N-diethylamino) butyl]-2-chlorophenoxazine (10-NCP)) or autophagy inhibitor (3-methyladenine). Results In vivo, decreased endoplasmic reticulum stress protein expression (phospho-eIF2α and ATF4) was observed at 3 h of reperfusion in CA3 neurons following ischemia, and increased in CA1 neurons at 12 h of reperfusion. In vitro, endoplasmic reticulum stress inducers and high doses of the endoplasmic reticulum stress inhibitors also increased cell death. Both induction and inhibition of autophagy also increased cell death. Conclusion Endoplasmic reticulum stress is associated with neuronal cell death following ischemia. Neither reduction of endoplasmic reticulum stress nor induction of autophagy demonstrated neuroprotection in vitro, highlighting their complex role in neuronal biology following ischemia.

  19. Cardiac gated ventilation

    International Nuclear Information System (INIS)

    Hanson, C.W. III; Hoffman, E.A.

    1995-01-01

    There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. The authors evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50 msec scan aperture. Multi slice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. The authors observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a non-failing model of the heart

  20. Induction of cortical endoplasmic reticulum by dimerization of a coatomer-binding peptide anchored to endoplasmic reticulum membranes

    OpenAIRE

    Lavieu, Grégory; Orci, Lelio; Shi, Lei; Geiling, Michael; Ravazzola, Mariella; Wieland, Felix; Cosson, Pierre; Rothman, James E.

    2010-01-01

    Cortical endoplasmic reticulum (cER) is a permanent feature of yeast cells but occurs transiently in most animal cell types. Ist2p is a transmembrane protein that permanently localizes to the cER in yeast. When Ist2 is expressed in mammalian cells, it induces abundant cER containing Ist2. Ist2 cytoplasmic C-terminal peptide is necessary and sufficient to induce cER. This peptide sequence resembles classic coat protein complex I (COPI) coatomer protein-binding KKXX signals, and indeed the dime...

  1. Ghrelin Ameliorates Asthma by Inhibiting Endoplasmic Reticulum Stress.

    Science.gov (United States)

    Fu, Tian; Wang, Lei; Zeng, Qingdi; Zhang, Yan; Sheng, Baowei; Han, Liping

    2017-12-01

    This study aimed to confirm the ameliorative effect of ghrelin on asthma and investigate its mechanism. The murine model of asthma was induced by ovalbumin (OVA) treatment and assessed by histological pathology and airway responsiveness to methacholine. The total and differential leukocytes were counted. Tumor necrosis factor α, interferon γ, interleukin-5 and interleukin-13 levels in bronchoalveolar lavage fluid were quantified by commercial kits. The protein levels in pulmonary tissues were measured by Western blot analysis. Ghrelin ameliorated the histological pathology and airway hyperresponsiveness in the OVA-induced asthmatic mouse model. Consistently, OVA-increased total and differential leukocytes and levels of tumor necrosis factor α, interferon γ, interleukin-5 and interleukin-13 in bronchoalveolar lavage fluid were significantly attenuated by ghrelin. Ghrelin prevented the increased protein levels of the endoplasmic reticulum stress markers glucose regulated protein 78 and CCAAT/enhancer binding protein homologous protein and reversed the reduced levels of p-Akt in asthmatic mice. Ghrelin might prevent endoplasmic reticulum stress activation by stimulating the Akt signaling pathway, which attenuated inflammation and ameliorated asthma in mice. Ghrelin might be a new target for asthma therapy. Copyright © 2017. Published by Elsevier Inc.

  2. Ricin A chain reaches the endoplasmic reticulum after endocytosis

    International Nuclear Information System (INIS)

    Liu Qiong; Zhan Jinbiao; Chen Xinhong; Zheng Shu

    2006-01-01

    Ricin is a potent ribosome inactivating protein and now has been widely used for synthesis of immunotoxins. To target ribosome in the mammalian cytosol, ricin must firstly retrograde transport from the endomembrane system to reach the endoplasmic reticulum (ER) where the ricin A chain (RTA) is recognized by ER components that facilitate its membrane translocation to the cytosol. In the study, the fusion gene of enhanced green fluorescent protein (EGFP)-RTA was expressed with the pET-28a (+) system in Escherichia coli under the control of a T7 promoter. The fusion protein showed a green fluorescence. The recombinant protein can be purified by metal chelated affinity chromatography on a column of NTA. The rabbit anti-GFP antibody can recognize the fusion protein of EGFP-RTA just like the EGFP protein. The cytotoxicity of EGFP-RTA and RTA was evaluated by the MTT assay in HeLa and HEP-G2 cells following fluid-phase endocytosis. The fusion protein had a similar cytotoxicity of RTA. After endocytosis, the subcellular location of the fusion protein can be observed with the laser scanning confocal microscopy and the immuno-gold labeling Electro Microscopy. This study provided important evidence by a visualized way to prove that RTA does reach the endoplasmic reticulum

  3. Variable Stars in Large Magellanic Cloud Globular Clusters. III. Reticulum

    Science.gov (United States)

    Kuehn, Charles A.; Dame, Kyra; Smith, Horace A.; Catelan, Márcio; Jeon, Young-Beom; Nemec, James M.; Walker, Alistair R.; Kunder, Andrea; Pritzl, Barton J.; De Lee, Nathan; Borissova, Jura

    2013-06-01

    This is the third in a series of papers studying the variable stars in old globular clusters in the Large Magellanic Cloud. The primary goal of this series is to look at how the characteristics and behavior of RR Lyrae stars in Oosterhoff-intermediate systems compare to those of their counterparts in Oosterhoff-I/II systems. In this paper we present the results of our new time-series BVI photometric study of the globular cluster Reticulum. We found a total of 32 variables stars (22 RRab, 4 RRc, and 6 RRd stars) in our field of view. We present photometric parameters and light curves for these stars. We also present physical properties, derived from Fourier analysis of light curves, for some of the RR Lyrae stars. We discuss the Oosterhoff classification of Reticulum and use our results to re-derive the distance modulus and age of the cluster. Based on observations taken with the SMARTS 1.3 m telescope operated by the SMARTS Consortium and observations taken at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

  4. Observation of endoplasmic reticulum tubules via TOF-SIMS tandem mass spectrometry imaging of transfected cells.

    Science.gov (United States)

    Chini, Corryn E; Fisher, Gregory L; Johnson, Ben; Tamkun, Michael M; Kraft, Mary L

    2018-02-26

    Advances in three-dimensional secondary ion mass spectrometry (SIMS) imaging have enabled visualizing the subcellular distributions of various lipid species within individual cells. However, the difficulty of locating organelles using SIMS limits efforts to study their lipid compositions. Here, the authors have assessed whether endoplasmic reticulum (ER)-Tracker Blue White DPX ® , which is a commercially available stain for visualizing the endoplasmic reticulum using fluorescence microscopy, produces distinctive ions that can be used to locate the endoplasmic reticulum using SIMS. Time-of-flight-SIMS tandem mass spectrometry (MS 2 ) imaging was used to identify positively and negatively charged ions produced by the ER-Tracker stain. Then, these ions were used to localize the stain and thus the endoplasmic reticulum, within individual human embryonic kidney cells that contained higher numbers of endoplasmic reticulum-plasma membrane junctions on their surfaces. By performing MS 2 imaging of selected ions in parallel with the precursor ion (MS 1 ) imaging, the authors detected a chemical interference native to the cell at the same nominal mass as the pentafluorophenyl fragment from the ER-Tracker stain. Nonetheless, the fluorine secondary ions produced by the ER-Tracker stain provided a distinctive signal that enabled locating the endoplasmic reticulum using SIMS. This simple strategy for visualizing the endoplasmic reticulum in individual cells using SIMS could be combined with existing SIMS methodologies for imaging intracellular lipid distribution and to study the lipid composition within the endoplasmic reticulum.

  5. Gel-based phosphoproteomics analysis of sarcoplasmic proteins in postmortem porcine muscle with pH decline rate and time differences

    DEFF Research Database (Denmark)

    Huang, Honggang; Larsen, Martin Røssel; Karlsson, Anders H

    2011-01-01

    phosphorylation in sarcoplasmic proteins from three groups of pigs with different pH decline rates from PM 1 to 24¿h. Globally, the fast pH decline group had the highest phosphorylation level at PM 1¿h, but lowest at 24¿h, whereas the slow pH decline group showed the reverse case. The same pattern was also...... observed in most individual bands in 1-DE. The protein phosphorylation levels of 12 bands were significantly affected by the synergy effects of pH and time (p......Meat quality development is highly influenced by the pH decline caused by the postmortem (PM) glycolysis. Protein phosphorylation is an important mechanism in regulating the activity of glycometabolic enzymes. Here, a gel-based phosphoproteomic study was performed to analyze the protein...

  6. Stimulating endogenous cardiac regeneration

    Directory of Open Access Journals (Sweden)

    Amanda eFinan

    2015-09-01

    Full Text Available The healthy adult heart has a low turnover of cardiac myocytes. The renewal capacity, however, is augmented after cardiac injury. Participants in cardiac regeneration include cardiac myocytes themselves, cardiac progenitor cells, and peripheral stem cells, particularly from the bone marrow compartment. Cardiac progenitor cells and bone marrow stem cells are augmented after cardiac injury, migrate to the myocardium, and support regeneration. Depletion studies of these populations have demonstrated their necessary role in cardiac repair. However, the potential of these cells to completely regenerate the heart is limited. Efforts are now being focused on ways to augment these natural pathways to improve cardiac healing, primarily after ischemic injury but in other cardiac pathologies as well. Cell and gene therapy or pharmacological interventions are proposed mechanisms. Cell therapy has demonstrated modest results and has passed into clinical trials. However, the beneficial effects of cell therapy have primarily been their ability to produce paracrine effects on the cardiac tissue and recruit endogenous stem cell populations as opposed to direct cardiac regeneration. Gene therapy efforts have focused on prolonging or reactivating natural signaling pathways. Positive results have been demonstrated to activate the endogenous stem cell populations and are currently being tested in clinical trials. A potential new avenue may be to refine pharmacological treatments that are currently in place in the clinic. Evidence is mounting that drugs such as statins or beta blockers may alter endogenous stem cell activity. Understanding the effects of these drugs on stem cell repair while keeping in mind their primary function may strike a balance in myocardial healing. To maximize endogenous cardiac regeneration,a combination of these approaches couldameliorate the overall repair process to incorporate the participation ofmultiple cell players.

  7. Marketing cardiac CT programs.

    Science.gov (United States)

    Scott, Jason

    2010-01-01

    There are two components of cardiac CT discussed in this article: coronary artery calcium scoring (CACS) and coronary computed tomography angiography (CCTA).The distinctive advantages of each CT examination are outlined. In order to ensure a successful cardiac CT program, it is imperative that imaging facilities market their cardiac CT practices effectively in order to gain a competitive advantage in this valuable market share. If patients receive quality care by competent individuals, they are more likely to recommend the facility's cardiac CT program. Satisfied patients will also be more willing to come back for any further testing.

  8. Modeling of axonal endoplasmic reticulum network by spastic paraplegia proteins.

    Science.gov (United States)

    Yalçın, Belgin; Zhao, Lu; Stofanko, Martin; O'Sullivan, Niamh C; Kang, Zi Han; Roost, Annika; Thomas, Matthew R; Zaessinger, Sophie; Blard, Olivier; Patto, Alex L; Sohail, Anood; Baena, Valentina; Terasaki, Mark; O'Kane, Cahir J

    2017-07-25

    Axons contain a smooth tubular endoplasmic reticulum (ER) network that is thought to be continuous with ER throughout the neuron; the mechanisms that form this axonal network are unknown. Mutations affecting reticulon or REEP proteins, with intramembrane hairpin domains that model ER membranes, cause an axon degenerative disease, hereditary spastic paraplegia (HSP). We show that Drosophila axons have a dynamic axonal ER network, which these proteins help to model. Loss of HSP hairpin proteins causes ER sheet expansion, partial loss of ER from distal motor axons, and occasional discontinuities in axonal ER. Ultrastructural analysis reveals an extensive ER network in axons, which shows larger and fewer tubules in larvae that lack reticulon and REEP proteins, consistent with loss of membrane curvature. Therefore HSP hairpin-containing proteins are required for shaping and continuity of axonal ER, thus suggesting roles for ER modeling in axon maintenance and function.

  9. Plant transducers of the endoplasmic reticulum unfolded protein response

    KAUST Repository

    Iwata, Yuji; Koizumi, Nozomu

    2012-01-01

    The unfolded protein response (UPR) activates a set of genes to overcome accumulation of unfolded proteins in the endoplasmic reticulum (ER), a condition termed ER stress, and constitutes an essential part of ER protein quality control that ensures efficient maturation of secretory and membrane proteins in eukaryotes. Recent studies on Arabidopsis and rice identified the signaling pathway in which the ER membrane-localized ribonuclease IRE1 (inositol-requiring enzyme 1) catalyzes unconventional cytoplasmic splicing of mRNA, thereby producing the active transcription factor Arabidopsis bZIP60 (basic leucine zipper 60) and its ortholog in rice. Here we review recent findings identifying the molecular components of the plant UPR, including IRE1/bZIP60 and the membrane-bound transcription factors bZIP17 and bZIP28, and implicating its importance in several physiological phenomena such as pathogen response. © 2012 Elsevier Ltd.

  10. Endoplasmic Reticulum Stress-Related Factors Protect against Diabetic Retinopathy

    Directory of Open Access Journals (Sweden)

    Wei-Kun Hu

    2012-01-01

    Full Text Available The endoplasmic reticulum (ER is a principal mediator of signal transduction in the cell, and disruption of its normal function (a mechanism known as ER stress has been associated with the pathogenesis of several diseases. ER stress has been demonstrated to contribute to onset and progression of diabetic retinopathy (DR by induction of multiple inflammatory signaling pathways. Recent studies have begun to describe the gene expression profile of ER stress-related genes in DR; moreover, genes that play a protective role against DR have been identified. P58IPK was determined to be able to reduce retinal vascular leakage under high glucose conditions, thus protecting retinal cells. It has also been found by our lab that ER-associated protein degradation factors exhibit significantly different expression patterns in rat retinas under sustained high glucose conditions. Future research based upon these collective genomic findings will contribute to our overall understanding of DR pathogenesis as well as identify potential therapeutic targets.

  11. Plant transducers of the endoplasmic reticulum unfolded protein response

    KAUST Repository

    Iwata, Yuji

    2012-12-01

    The unfolded protein response (UPR) activates a set of genes to overcome accumulation of unfolded proteins in the endoplasmic reticulum (ER), a condition termed ER stress, and constitutes an essential part of ER protein quality control that ensures efficient maturation of secretory and membrane proteins in eukaryotes. Recent studies on Arabidopsis and rice identified the signaling pathway in which the ER membrane-localized ribonuclease IRE1 (inositol-requiring enzyme 1) catalyzes unconventional cytoplasmic splicing of mRNA, thereby producing the active transcription factor Arabidopsis bZIP60 (basic leucine zipper 60) and its ortholog in rice. Here we review recent findings identifying the molecular components of the plant UPR, including IRE1/bZIP60 and the membrane-bound transcription factors bZIP17 and bZIP28, and implicating its importance in several physiological phenomena such as pathogen response. © 2012 Elsevier Ltd.

  12. How are proteins reduced in the endoplasmic reticulum?

    DEFF Research Database (Denmark)

    Ellgaard, Lars; Sevier, Carolyn S.; Bulleid, Neil J.

    2018-01-01

    The reversal of thiol oxidation in proteins within the endoplasmic reticulum (ER) is crucial for protein folding, degradation, chaperone function, and the ER stress response. Our understanding of this process is generally poor but progress has been made. Enzymes performing the initial reduction...... of client proteins, as well as the ultimate electron donor in the pathway, have been identified. Most recently, a role for the cytosol in ER protein reduction has been revealed. Nevertheless, how reducing equivalents are transferred from the cytosol to the ER lumen remains an open question. We review here...... why proteins are reduced in the ER, discuss recent data on catalysis of steps in the pathway, and consider the implications for redox homeostasis within the early secretory pathway....

  13. Osteochondritis dissecans (OCD), an endoplasmic reticulum storage disease?

    DEFF Research Database (Denmark)

    Skagen, Peter Storgaard; Horn, T; Kruse, H A

    2011-01-01

    in chondrocytes and extracellular matrix of cartilage from OCD patients. Abnormal type II collagen heterofibrils in "bundles" and chondrocytes with abnormal accumulation of matrix proteins in distended rough endoplasmic reticulum were typical findings. Further, Von Kossa staining and TEM showed empty lacunae...... close to mineralized "islands" in the cartilage and hypertrophic chondrocytes containing accumulated matrix proteins. Immunostaining revealed: (1) that types I, II, VI and X collagens and aggrecans were deposited intracellulary and (2) co-localization within the islands of types I, II, X collagens...... and aggrecan indicating that hypertrophic chondrocytes express a phenotype of bone cells during endochondral ossification. Types I, VI and X collagens were also present across the entire dissecates suggesting that chondrocytes were dedifferentiated. DNA sequencings were non-conclusive, only single nucleotide...

  14. Safety in cardiac surgery

    NARCIS (Netherlands)

    Siregar, S.

    2013-01-01

    The monitoring of safety in cardiac surgery is a complex process, which involves many clinical, practical, methodological and statistical issues. The objective of this thesis was to measure and to compare safety in cardiac surgery in The Netherlands using the Netherlands Association for

  15. Cardiac Catheterization (For Kids)

    Science.gov (United States)

    ... First Aid & Safety Doctors & Hospitals Videos Recipes for Kids Kids site Sitio para niños How the Body Works ... Educators Search English Español Cardiac Catheterization KidsHealth / For Kids / Cardiac Catheterization What's in this article? What Is ...

  16. Sudden cardiac death

    Directory of Open Access Journals (Sweden)

    Neeraj Parakh

    2015-01-01

    Full Text Available Sudden cardiac death is one of the most common cause of mortality worldwide. Despite significant advances in the medical science, there is little improvement in the sudden cardiac death related mortality. Coronary artery disease is the most common etiology behind sudden cardiac death, in the above 40 years population. Even in the apparently healthy population, there is a small percentage of patients dying from sudden cardiac death. Given the large denominator, this small percentage contributes to the largest burden of sudden cardiac death. Identification of this at risk group among the apparently healthy individual is a great challenge for the medical fraternity. This article looks into the causes and methods of preventing SCD and at some of the Indian data. Details of Brugada syndrome, Long QT syndrome, Genetics of SCD are discussed. Recent guidelines on many of these causes are summarised.

  17. CARDIAC LYMPHOMA IN DOG

    Directory of Open Access Journals (Sweden)

    G. D. Cruz

    2016-11-01

    Full Text Available Lymphoma is a lymphoid tumor that originates in hematopoietic organs such as lymph node, spleen or liver. In dogs, the overall prevalence of cardiac tumors was estimated to be only 0.19% based on the results of the survey of a large database, and lymphomas accounts for approximately 2% of all cardiac tumors. In general, the involvement of the myocardium is rarely described in canine lymphoma. Currently, there is no evidence of a viral association with primary cardiac lymphoma in dogs, but other types of immunosuppression may contribute to abnormal events, such as involvement primary cardiac. The aim of this study was to analyze a case of sudden death of a bitch, SRD, aged 10, who had the final diagnosis of cardiac lymphoma.

  18. Mathematical cardiac electrophysiology

    CERN Document Server

    Colli Franzone, Piero; Scacchi, Simone

    2014-01-01

    This book covers the main mathematical and numerical models in computational electrocardiology, ranging from microscopic membrane models of cardiac ionic channels to macroscopic bidomain, monodomain, eikonal models and cardiac source representations. These advanced multiscale and nonlinear models describe the cardiac bioelectrical activity from the cell level to the body surface and are employed in both the direct and inverse problems of electrocardiology. The book also covers advanced numerical techniques needed to efficiently carry out large-scale cardiac simulations, including time and space discretizations, decoupling and operator splitting techniques, parallel finite element solvers. These techniques are employed in 3D cardiac simulations illustrating the excitation mechanisms, the anisotropic effects on excitation and repolarization wavefronts, the morphology of electrograms in normal and pathological tissue and some reentry phenomena. The overall aim of the book is to present rigorously the mathematica...

  19. Biomaterials for cardiac regeneration

    CERN Document Server

    Ruel, Marc

    2015-01-01

    This book offers readers a comprehensive biomaterials-based approach to achieving clinically successful, functionally integrated vasculogenesis and myogenesis in the heart. Coverage is multidisciplinary, including the role of extracellular matrices in cardiac development, whole-heart tissue engineering, imaging the mechanisms and effects of biomaterial-based cardiac regeneration, and autologous bioengineered heart valves. Bringing current knowledge together into a single volume, this book provides a compendium to students and new researchers in the field and constitutes a platform to allow for future developments and collaborative approaches in biomaterials-based regenerative medicine, even beyond cardiac applications. This book also: Provides a valuable overview of the engineering of biomaterials for cardiac regeneration, including coverage of combined biomaterials and stem cells, as well as extracellular matrices Presents readers with multidisciplinary coverage of biomaterials for cardiac repair, including ...

  20. Role of epidermal growth factor receptor and endoplasmic reticulum stress in vascular remodeling induced by angiotensin II.

    Science.gov (United States)

    Takayanagi, Takehiko; Kawai, Tatsuo; Forrester, Steven J; Obama, Takashi; Tsuji, Toshiyuki; Fukuda, Yamato; Elliott, Katherine J; Tilley, Douglas G; Davisson, Robin L; Park, Joon-Young; Eguchi, Satoru

    2015-06-01

    The mechanisms by which angiotensin II (AngII) elevates blood pressure and enhances end-organ damage seem to be distinct. However, the signal transduction cascade by which AngII specifically mediates vascular remodeling such as medial hypertrophy and perivascular fibrosis remains incomplete. We have previously shown that AngII-induced epidermal growth factor receptor (EGFR) transactivation is mediated by disintegrin and metalloproteinase domain 17 (ADAM17), and that this signaling is required for vascular smooth muscle cell hypertrophy but not for contractile signaling in response to AngII. Recent studies have implicated endoplasmic reticulum (ER) stress in hypertension. Interestingly, EGFR is capable of inducing ER stress. The aim of this study was to test the hypothesis that activation of EGFR and ER stress are critical components required for vascular remodeling but not hypertension induced by AngII. Mice were infused with AngII for 2 weeks with or without treatment of EGFR inhibitor, erlotinib, or ER chaperone, 4-phenylbutyrate. AngII infusion induced vascular medial hypertrophy in the heart, kidney and aorta, and perivascular fibrosis in heart and kidney, cardiac hypertrophy, and hypertension. Treatment with erlotinib as well as 4-phenylbutyrate attenuated vascular remodeling and cardiac hypertrophy but not hypertension. In addition, AngII infusion enhanced ADAM17 expression, EGFR activation, and ER/oxidative stress in the vasculature, which were diminished in both erlotinib-treated and 4-phenylbutyrate-treated mice. ADAM17 induction and EGFR activation by AngII in vascular cells were also prevented by inhibition of EGFR or ER stress. In conclusion, AngII induces vascular remodeling by EGFR activation and ER stress via a signaling mechanism involving ADAM17 induction independent of hypertension. © 2015 American Heart Association, Inc.

  1. Activation of NADPH oxidase mediates increased endoplasmic reticulum stress and left ventricular remodeling after myocardial infarction in rabbits.

    Science.gov (United States)

    Li, Bao; Tian, Jing; Sun, Yi; Xu, Tao-Rui; Chi, Rui-Fang; Zhang, Xiao-Li; Hu, Xin-Ling; Zhang, Yue-An; Qin, Fu-Zhong; Zhang, Wei-Fang

    2015-05-01

    Nicotinamide adenine dinucleotide 3-phosphate (NADPH) oxidase activity and endoplasmic reticulum (ER) stress are increased after myocardial infarction (MI). In this study, we proposed to test whether activation of the NADPH oxidase in the remote non-infarcted myocardium mediates ER stress and left ventricular (LV) remodeling after MI. Rabbits with MI or sham operation were randomly assigned to orally receive an NADPH oxidase inhibitor apocynin or placebo for 30 days. The agents were administered beginning at 1 week after surgery. MI rabbits exhibited decreases in LV fractional shortening, LV ejection fraction and the first derivative of the LV pressure rise, which were abolished by apocynin treatment. NADPH oxidase Nox2 protein and mRNA expressions were increased in the remote non-infarcted myocardium after MI. Immunolabeling further revealed that Nox2 was increased in cardiac myocytes in the remote myocardium. The apocynin treatment prevented increases in the Nox2 expression, NADPH oxidase activity, oxidative stress, myocyte apoptosis and GRP78, CHOP and cleaved caspase 12 protein expression in the remote myocardium. The apocynin treatment also attenuated increases in myocyte diameter and cardiac fibrosis. In cultured H9C2 cardiomyocytes exposed to angiotensin II, an important stimulus for post-MI remodeling, Nox2 knockdown with siRNA significantly inhibited angiotensin II-induced NADPH oxidase activation, reactive oxygen species and GRP78 and CHOP protein expression. We conclude that NADPH oxidase inhibition attenuates increased ER stress in the remote non-infarcted myocardium and LV remodeling late after MI in rabbits. These findings suggest that the activation of NADPH oxidase in the remote non-infarcted myocardium mediates increased ER stress, contributing to myocyte apoptosis and LV remodeling after MI. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Sch proteins are localized on endoplasmic reticulum membranes and are redistributed after tyrosine kinase receptor activation

    DEFF Research Database (Denmark)

    Lotti, L V; Lanfrancone, L; Migliaccio, E

    1996-01-01

    area of the cell and mostly associated with the cytosolic side of rough endoplasmic reticulum membranes. Upon epidermal growth factor treatment and receptor tyrosine kinase activation, the immunolabeling became peripheral and was found to be associated with the cytosolic surface of the plasma membrane....... The rough endoplasmic reticulum localization of Shc proteins in unstimulated cells and their massive recruitment to the plasma membrane, endocytic structures, and peripheral cytosol following receptor tyrosine kinase activation could account for multiple putative functions of the adaptor protein....

  3. Comprehensive cardiac rehabilitation

    DEFF Research Database (Denmark)

    Kruse, Marie; Hochstrasser, Stefan; Zwisler, Ann-Dorthe O

    2006-01-01

    OBJECTIVES: The costs of comprehensive cardiac rehabilitation are established and compared to the corresponding costs of usual care. The effect on health-related quality of life is analyzed. METHODS: An unprecedented and very detailed cost assessment was carried out, as no guidelines existed...... and may be as high as euro 1.877. CONCLUSIONS: Comprehensive cardiac rehabilitation is more costly than usual care, and the higher costs are not outweighed by a quality of life gain. Comprehensive cardiac rehabilitation is, therefore, not cost-effective....

  4. Dual energy cardiac CT.

    Science.gov (United States)

    Carrascosa, Patricia; Deviggiano, Alejandro; Rodriguez-Granillo, Gastón

    2017-06-01

    Conventional single energy CT suffers from technical limitations related to the polychromatic nature of X-rays. Dual energy cardiac CT (DECT) shows promise to attenuate and even overcome some of these limitations, and might broaden the scope of patients eligible for cardiac CT towards the inclusion of higher risk patients. This might be achieved as a result of both safety (contrast reduction) and physiopathological (myocardial perfusion and characterization) issues. In this article, we will review the main clinical cardiac applications of DECT, that can be summarized in two core aspects: coronary artery evaluation, and myocardial evaluation.

  5. Aggregation and retention of human urokinase type plasminogen activator in the yeast endoplasmic reticulum

    Directory of Open Access Journals (Sweden)

    Smirnov Vladimir N

    2002-10-01

    Full Text Available Abstract Background Secretion of recombinant proteins in yeast can be affected by their improper folding in the endoplasmic reticulum and subsequent elimination of the misfolded molecules via the endoplasmic reticulum associated protein degradation pathway. Recombinant proteins can also be degraded by the vacuolar protease complex. Human urokinase type plasminogen activator (uPA is poorly secreted by yeast but the mechanisms interfering with its secretion are largely unknown. Results We show that in Hansenula polymorpha overexpression worsens uPA secretion and stimulates its intracellular aggregation. The absence of the Golgi modifications in accumulated uPA suggests that aggregation occurs within the endoplasmic reticulum. Deletion analysis has shown that the N-terminal domains were responsible for poor uPA secretion and propensity to aggregate. Mutation abolishing N-glycosylation decreased the efficiency of uPA secretion and increased its aggregation degree. Retention of uPA in the endoplasmic reticulum stimulates its aggregation. Conclusions The data obtained demonstrate that defect of uPA secretion in yeast is related to its retention in the endoplasmic reticulum. Accumulation of uPA within the endoplasmic reticulum disturbs its proper folding and leads to formation of high molecular weight aggregates.

  6. Protein bodies in leaves exchange contents through the endoplasmic reticulum

    Directory of Open Access Journals (Sweden)

    Reza eSaberianfar

    2016-05-01

    Full Text Available Protein bodies (PBs are organelles found in seeds whose main function is the storage of proteins that are used during germination for sustaining growth. PBs can also be induced to form in leaves when foreign proteins are produced at high levels in the endoplasmic reticulum (ER and when fused to one of three tags: Zera®, elastin-like polypeptides (ELP, or hydrophobin-I (HFBI. In this study, we investigate the differences between ELP, HFBI and Zera PB formation, packing, and communication. Our results confirm the ER origin of all three fusion-tag-induced PBs. We show that secretory pathway proteins can be sequestered into all types of PBs but with different patterns, and that different fusion tags can target a specific protein to different PBs. Zera PBs are mobile and dependent on actomyosin motility similar to ELP and HFBI PBs. We show in vivo trafficking of proteins between PBs using GFP photoconversion. We also show that protein trafficking between ELP or HFBI PBs is faster and proteins travel further when compared to Zera PBs. Our results indicate that fusion-tag-induced PBs do not represent terminally stored cytosolic organelles, but that they form in, and remain part of the ER, and dynamically communicate with each other via the ER. We hypothesize that the previously documented PB mobility along the actin cytoskeleton is associated with ER movement rather than independent streaming of detached organelles.

  7. Arachidonoyl-specific diacylglycerol kinase ε and the endoplasmic reticulum

    Directory of Open Access Journals (Sweden)

    Tomoyuki Nakano

    2016-11-01

    Full Text Available The endoplasmic reticulum (ER comprises an interconnected membrane network, which is made up of lipid bilayer and associated proteins. This organelle plays a central role in the protein synthesis and sorting. In addition, it represents the synthetic machinery of phospholipids, the major constituents of the biological membrane. In this process, phosphatidic acid (PA serves as a precursor of all phospholipids, suggesting that PA synthetic activity is closely associated with the ER function. One enzyme responsible for PA synthesis is diacylglycerol kinase (DGK that phosphorylates diacylglycerol (DG to PA. DGK is composed of a family of enzymes with distinct features assigned to each isozyme in terms of structure, enzymology and subcellular localization. Of DGKs, DGKε uniquely exhibits substrate specificity toward arachidonate-containing DG and is shown to reside in the ER. Arachidonic acid, a precursor of bioactive eicosanoids, is usually acylated at the sn-2 position of phospholipids, being especially enriched in phosphoinositide. In this review, we focus on arachidonoyl-specific DGKε with respect to the historical context, molecular basis of the substrate specificity and ER-targeting, and functional implications in the ER.

  8. Dietary toxins, endoplasmic reticulum (ER) stress and diabetes.

    Science.gov (United States)

    Hettiarachchi, Kalindi D; Zimmet, Paul Z; Myers, Mark A

    2008-05-01

    The incidence of Type 1 diabetes has been increasing at a rate too rapid to be due to changes in genetic risk. Instead changes in environmental factors are the likely culprit. The endoplasmic reticulum (ER) plays an important role in the production of newly synthesized proteins and interference with these processes leads to ER stress. The insulin-producing beta cells are particularly prone to ER stress as a result of their heavy engagement in insulin production. Increasing evidence suggests ER stress is central to initiation and progression of Type 1 diabetes. An early environmental exposure, such as toxins and viral infections, can impart a significant physiological load on beta cells to initiate abnormal processing of proinsulin, ER stress and insulin secretory defects. Release of altered proinsulin from the beta cells early in life may trigger autoimmunity in those with genetic susceptibility leading to cytokine-induced nitric oxide production and so exacerbating ER stress in beta cells, ultimately leading to apoptosis of beta cells and diabetes. Here we suggest that ER stress is an inherent cause of beta cell dysfunction and environmental factors, in particular dietary toxins derived from Streptomyces in infected root vegetables, can impart additional stress that aggravates beta cell death and progression to diabetes. Furthermore, we propose that the increasing incidence of Type 1 diabetes may be accounted for by increased dietary exposure to ER-stress-inducing Streptomyces toxins.

  9. Endoplasmic Reticulum Stress, Unfolded Protein Response, and Cancer Cell Fate

    Directory of Open Access Journals (Sweden)

    Marco Corazzari

    2017-04-01

    Full Text Available Perturbation of endoplasmic reticulum (ER homeostasis results in a stress condition termed “ER stress” determining the activation of a finely regulated program defined as unfolded protein response (UPR and whose primary aim is to restore this organelle’s physiological activity. Several physiological and pathological stimuli deregulate normal ER activity causing UPR activation, such as hypoxia, glucose shortage, genome instability, and cytotoxic compounds administration. Some of these stimuli are frequently observed during uncontrolled proliferation of transformed cells, resulting in tumor core formation and stage progression. Therefore, it is not surprising that ER stress is usually induced during solid tumor development and stage progression, becoming an hallmark of such malignancies. Several UPR components are in fact deregulated in different tumor types, and accumulating data indicate their active involvement in tumor development/progression. However, although the UPR program is primarily a pro-survival process, sustained and/or prolonged stress may result in cell death induction. Therefore, understanding the mechanism(s regulating the cell survival/death decision under ER stress condition may be crucial in order to specifically target tumor cells and possibly circumvent or overcome tumor resistance to therapies. In this review, we discuss the role played by the UPR program in tumor initiation, progression and resistance to therapy, highlighting the recent advances that have improved our understanding of the molecular mechanisms that regulate the survival/death switch.

  10. Endoplasmic-reticulum-mediated microtubule alignment governs cytoplasmic streaming.

    Science.gov (United States)

    Kimura, Kenji; Mamane, Alexandre; Sasaki, Tohru; Sato, Kohta; Takagi, Jun; Niwayama, Ritsuya; Hufnagel, Lars; Shimamoto, Yuta; Joanny, Jean-François; Uchida, Seiichi; Kimura, Akatsuki

    2017-04-01

    Cytoplasmic streaming refers to a collective movement of cytoplasm observed in many cell types. The mechanism of meiotic cytoplasmic streaming (MeiCS) in Caenorhabditis elegans zygotes is puzzling as the direction of the flow is not predefined by cell polarity and occasionally reverses. Here, we demonstrate that the endoplasmic reticulum (ER) network structure is required for the collective flow. Using a combination of RNAi, microscopy and image processing of C. elegans zygotes, we devise a theoretical model, which reproduces and predicts the emergence and reversal of the flow. We propose a positive-feedback mechanism, where a local flow generated along a microtubule is transmitted to neighbouring regions through the ER. This, in turn, aligns microtubules over a broader area to self-organize the collective flow. The proposed model could be applicable to various cytoplasmic streaming phenomena in the absence of predefined polarity. The increased mobility of cortical granules by MeiCS correlates with the efficient exocytosis of the granules to protect the zygotes from osmotic and mechanical stresses.

  11. A Molecular Web: Endoplasmic Reticulum Stress, Inflammation and Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Namrata eChaudhari

    2014-07-01

    Full Text Available Execution of fundamental cellular functions demands regulated protein folding homeostasis. Endoplasmic reticulum (ER is an active organelle existing to implement this function by folding and modifying secretory and membrane proteins. Loss of protein folding homeostasis is central to various diseases and budding evidences suggest ER stress as being a major contributor in the development or pathology of a diseased state besides other cellular stresses. The trigger for diseases may be diverse but, inflammation and/or ER stress may be basic mechanisms increasing the severity or complicating the condition of the disease. Chronic ER stress and activation of the unfolded protein response (UPR through endogenous or exogenous insults may result in impaired calcium and redox homeostasis, oxidative stress via protein overload thereby also influencing vital mitochondrial functions. Calcium released from the ER augments the production of mitochondrial Reactive Oxygen Species (ROS. Toxic accumulation of ROS within ER and mitochondria disturb fundamental organelle functions. Sustained ER stress is known to potentially elicit inflammatory responses via UPR pathways. Additionally, ROS generated through inflammation or mitochondrial dysfunction could accelerate ER malfunction. Dysfunctional UPR pathways has been associated with a wide range of diseases including several neurodegenerative diseases, stroke, metabolic disorders, cancer, inflammatory disease, diabetes mellitus, cardiovascular disease and others. In this review we have discussed the UPR signaling pathways, and networking between ER stress induced inflammatory pathways, oxidative stress and mitochondrial signaling events which further induce or exacerbate ER stress.

  12. STIM proteins and the endoplasmic reticulum-plasma membrane junctions.

    Science.gov (United States)

    Carrasco, Silvia; Meyer, Tobias

    2011-01-01

    Eukaryotic organelles can interact with each other through stable junctions where the two membranes are kept in close apposition. The junction that connects the endoplasmic reticulum to the plasma membrane (ER-PM junction) is unique in providing a direct communication link between the ER and the PM. In a recently discovered signaling process, STIM (stromal-interacting molecule) proteins sense a drop in ER Ca(2+) levels and directly activate Orai PM Ca(2+) channels across the junction space. In an inverse process, a voltage-gated PM Ca(2+) channel can directly open ER ryanodine-receptor Ca(2+) channels in striated-muscle cells. Although ER-PM junctions were first described 50 years ago, their broad importance in Ca(2+) signaling, as well as in the regulation of cholesterol and phosphatidylinositol lipid transfer, has only recently been realized. Here, we discuss research from different fields to provide a broad perspective on the structures and unique roles of ER-PM junctions in controlling signaling and metabolic processes.

  13. Hypothalamic endoplasmic reticulum stress of overtrained mice after recovery

    Directory of Open Access Journals (Sweden)

    Ana P. Pinto

    2017-05-01

    Full Text Available Abstract AIMS knowing the relationship between endoplasmic reticulum (ER stress and inflammation and based on the fact that downhill running-based overtraining (OT model increases hypothalamus levels of some pro-inflammatory cytokines, we verified the effects of three OT protocols on the levels of BiP, pIRE-1 (Ser734, pPERK (Thr981, pelF2alpha (Ser52, ATF-6 and GRP-94 proteins in the mouse hypothalamus after two weeks of recovery. METHODS the mice were randomized into control (CT, overtrained by downhill running (OTR/down, overtrained by uphill running (OTR/up and overtrained by running without inclination (OTR groups. After 2-week total recovery period (i.e., week 10, hypothalamus was removed and used for immunoblotting. RESULTS the OTR/down group exhibited high levels of BiP and ATF6. The other OT protocols showed higher levels of pPERK (Th981 and pelf-2alpha (Ser52 when compared with the CT group. CONCLUSION the current results suggest that after a 2-week total recovery period, the overtrained groups increased partially their ER stress protein levels, but without hypothalamic inflammation, which characterizes a physiological condition related to an adaptation mechanism.

  14. The endoplasmic reticulum in plant immunity and cell death.

    Science.gov (United States)

    Eichmann, Ruth; Schäfer, Patrick

    2012-01-01

    The endoplasmic reticulum (ER) is a highly dynamic organelle in eukaryotic cells and a major production site of proteins destined for vacuoles, the plasma membrane, or apoplast in plants. At the ER, these secreted proteins undergo multiple processing steps, which are supervised and conducted by the ER quality control system. Notably, processing of secreted proteins can considerably elevate under stress conditions and exceed ER folding capacities. The resulting accumulation of unfolded proteins is defined as ER stress. The efficiency of cells to re-establish proper ER function is crucial for stress adaptation. Besides delivering proteins directly antagonizing and resolving stress conditions, the ER monitors synthesis of immune receptors. This indicates the significance of the ER for the establishment and function of the plant immune system. Recent studies point out the fragility of the entire system and highlight the ER as initiator of programed cell death (PCD) in plants as was reported for vertebrates. This review summarizes current knowledge on the impact of the ER on immune and PCD signaling. Understanding the integration of stress signals by the ER bears a considerable potential to optimize development and to enhance stress resistance of plants.

  15. The endoplasmic reticulum in plant immunity and cell death

    Directory of Open Access Journals (Sweden)

    Patrick eSchäfer

    2012-08-01

    Full Text Available The endoplasmic reticulum (ER is a highly dynamic organelle in eukaryotic cells and a major production site of proteins destined for vacuoles, the plasma membrane or apoplast in plants. At the ER, these secreted proteins undergo multiple processing steps, which are supervised and conducted by the ER quality control system. Notably, processing of secreted proteins can considerably elevate under stress conditions and exceed ER folding capacities. The resulting accumulation of unfolded proteins is defined as ER stress. The efficiency of cells to re-establish proper ER function is crucial for stress adaptation. Besides delivering proteins directly antagonizing and resolving stress conditions, the ER monitors synthesis of immune receptors. This indicates the significance of the ER for the establishment and function of the plant immune system. Recent studies point out the fragility of the entire system and highlight the ER as initiator of programmed cell death (PCD in plants as was reported for vertebrates. This review summarizes current knowledge on the impact of the ER on immune and PCD signalling. Understanding the integration of stress signals by the ER bears a considerable potential to optimize development and to enhance stress resistance of plants.

  16. Heme oxygenase-1 comes back to endoplasmic reticulum

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hong Pyo [School of Biological Sciences, Ulsan University (Korea, Republic of); Pae, Hyun-Ock [Department of Immunology, Wonkwang University School of Medicine (Korea, Republic of); Back, Sung Hun; Chung, Su Wol [School of Biological Sciences, Ulsan University (Korea, Republic of); Woo, Je Moon [Department of Opthalmology, Ulasn University Hospital (Korea, Republic of); Son, Yong [Department of Anesthesiology and Pain Medicine, Wonkwang University School of Medicine (Korea, Republic of); Chung, Hun-Taeg, E-mail: chung@ulsan.ac.kr [School of Biological Sciences, Ulsan University (Korea, Republic of)

    2011-01-07

    Research highlights: {yields} Although multiple compartmentalization of HO-1 has been documented, the functional implication of this enzyme at these subcellular organelles is only partially elucidated. {yields} HO-1 expression at ER is induced by a diverse set of conditions that cause ER stressors. {yields} CO may induce HO-1 expression in human ECs by activating Nrf2 through PERK phosphorylation in a positive-feedback manner. {yields} ER-residing HO-1 and its cytoprotective activity against ER stress is discussed. -- Abstract: Originally identified as a rate-limiting enzyme for heme catabolism, heme oxygenase-1 (HO-1) has expanded its roles in anti-inflammation, anti-apoptosis and anti-proliferation for the last decade. Regulation of protein activity by location is well appreciated. Even though multiple compartmentalization of HO-1 has been documented, the functional implication of this enzyme at these subcellular organelles is only partially elucidated. In this review we discuss the endoplasmic reticulum (ER)-residing HO-1 and its cytoprotective activity against ER stress.

  17. Homocysteine inhibits hepatocyte proliferation via endoplasmic reticulum stress.

    Directory of Open Access Journals (Sweden)

    Xue Yu

    Full Text Available Homocysteine is an independent risk factor for coronary, cerebral, and peripheral vascular diseases. Recent studies have shown that levels of homocysteine are elevated in patients with impaired hepatic function, but the precise role of homocysteine in the development of hepatic dysfunction is unclear. In this study, we examined the effect of homocysteine on hepatocyte proliferation in vitro. Our results demonstrated that homocysteine inhibited hepatocyte proliferation by up-regulating protein levels of p53 as well as mRNA and protein levels of p21(Cip1 in primary cultured hepatocytes. Homocysteine induced cell growth arrest in p53-positive hepatocarcinoma cell line HepG2, but not in p53-null hepatocarcinoma cell line Hep3B. A p53 inhibitor pifithrin-α inhibited the expression of p21(Cip1 and attenuated homocysteine-induced cell growth arrest. Homocysteine induced TRB3 expression via endoplasmic reticulum stress pathway, resulting in Akt dephosphorylation. Knock-down of endogenous TRB3 significantly suppressed the inhibitory effect of homocysteine on cell proliferation and the phosphorylation of Akt. LiCl reversed homocysteine-mediated cell growth arrest by inhibiting TRB3-mediated Akt dephosphorylation. These results demonstrate that both TRB3 and p21(Cip1 are critical molecules in the homocysteine signaling cascade and provide a mechanistic explanation for impairment of liver regeneration in hyperhomocysteinemia.

  18. Cardiac Catheterization (For Parents)

    Science.gov (United States)

    ... cases, the doctor might call for a cardiac magnetic resonance imaging (MRI) scan or a CAT scan . ... first couple of days. This means no heavy lifting (more than 10 pounds) and no sports. After ...

  19. Cardiac Catheterization (For Teens)

    Science.gov (United States)

    ... doctor may also call for a cardiac MRI (magnetic resonance imaging) scan or a CT (computerized tomography) ... first couple of days. This means no heavy lifting (nothing over 10 pounds) and no sports. After ...

  20. Autonomic cardiac innervation

    Science.gov (United States)

    Hasan, Wohaib

    2013-01-01

    Autonomic cardiac neurons have a common origin in the neural crest but undergo distinct developmental differentiation as they mature toward their adult phenotype. Progenitor cells respond to repulsive cues during migration, followed by differentiation cues from paracrine sources that promote neurochemistry and differentiation. When autonomic axons start to innervate cardiac tissue, neurotrophic factors from vascular tissue are essential for maintenance of neurons before they reach their targets, upon which target-derived trophic factors take over final maturation, synaptic strength and postnatal survival. Although target-derived neurotrophins have a central role to play in development, alternative sources of neurotrophins may also modulate innervation. Both developing and adult sympathetic neurons express proNGF, and adult parasympathetic cardiac ganglion neurons also synthesize and release NGF. The physiological function of these “non-classical” cardiac sources of neurotrophins remains to be determined, especially in relation to autocrine/paracrine sustenance during development.   Cardiac autonomic nerves are closely spatially associated in cardiac plexuses, ganglia and pacemaker regions and so are sensitive to release of neurotransmitter, neuropeptides and trophic factors from adjacent nerves. As such, in many cardiac pathologies, it is an imbalance within the two arms of the autonomic system that is critical for disease progression. Although this crosstalk between sympathetic and parasympathetic nerves has been well established for adult nerves, it is unclear whether a degree of paracrine regulation occurs across the autonomic limbs during development. Aberrant nerve remodeling is a common occurrence in many adult cardiovascular pathologies, and the mechanisms regulating outgrowth or denervation are disparate. However, autonomic neurons display considerable plasticity in this regard with neurotrophins and inflammatory cytokines having a central regulatory

  1. Cardiac imaging in adults

    International Nuclear Information System (INIS)

    Jaffe, C.C.

    1987-01-01

    This book approaches adult cardiac disease from the correlative imaging perspective. It includes chest X-rays and angiographs, 2-dimensional echocardiograms with explanatory diagrams for clarity, plus details on digital radiology, nuclear medicine techniques, CT and MRI. It also covers the normal heart, valvular heart disease, myocardial disease, pericardial disease, bacterial endocarditis, aortic aneurysm, cardiac tumors, and congenital heart disease of the adult. It points out those aspects where one imaging technique has significant superiority

  2. Cardiac imaging in adults

    Energy Technology Data Exchange (ETDEWEB)

    Jaffe, C.C.

    1987-01-01

    This book approaches adult cardiac disease from the correlative imaging perspective. It includes chest X-rays and angiographs, 2-dimensional echocardiograms with explanatory diagrams for clarity, plus details on digital radiology, nuclear medicine techniques, CT and MRI. It also covers the normal heart, valvular heart disease, myocardial disease, pericardial disease, bacterial endocarditis, aortic aneurysm, cardiac tumors, and congenital heart disease of the adult. It points out those aspects where one imaging technique has significant superiority.

  3. Cardiac biomarkers in Neonatology

    OpenAIRE

    Vijlbrief, D.C.

    2015-01-01

    In this thesis, the role for cardiac biomarkers in neonatology was investigated. Several clinically relevant results were reported. In term and preterm infants, hypoxia and subsequent adaptation play an important role in cardiac biomarker elevation. The elevated natriuretic peptides are indicative of abnormal function; elevated troponins are suggestive for cardiomyocyte damage. This methodology makes these biomarkers of additional value in the treatment of newborn infants, separate or as a co...

  4. Post cardiac injury syndrome

    DEFF Research Database (Denmark)

    Nielsen, S L; Nielsen, F E

    1991-01-01

    The post-pericardiotomy syndrome is a symptom complex which is similar in many respects to the post-myocardial infarction syndrome and these are summarized under the diagnosis of the Post Cardiac Injury Syndrome (PCIS). This condition, which is observed most frequently after open heart surgery, i...... on the coronary vessels, with cardiac tamponade and chronic pericardial exudate. In the lighter cases, PCIS may be treated with NSAID and, in the more severe cases, with systemic glucocorticoid which has a prompt effect....

  5. Awareness in cardiac anesthesia.

    LENUS (Irish Health Repository)

    Serfontein, Leon

    2010-02-01

    Cardiac surgery represents a sub-group of patients at significantly increased risk of intraoperative awareness. Relatively few recent publications have targeted the topic of awareness in this group. The aim of this review is to identify areas of awareness research that may equally be extrapolated to cardiac anesthesia in the attempt to increase understanding of the nature and significance of this scenario and how to reduce it.

  6. Alcohol Dehydrogenase Protects against Endoplasmic Reticulum Stress-Induced Myocardial Contractile Dysfunction via Attenuation of Oxidative Stress and Autophagy: Role of PTEN-Akt-mTOR Signaling.

    Directory of Open Access Journals (Sweden)

    Jiaojiao Pang

    Full Text Available The endoplasmic reticulum (ER plays an essential role in ensuring proper folding of the newly synthesized proteins. Aberrant ER homeostasis triggers ER stress and development of cardiovascular diseases. ADH is involved in catalyzing ethanol to acetaldehyde although its role in cardiovascular diseases other than ethanol metabolism still remains elusive. This study was designed to examine the impact of ADH on ER stress-induced cardiac anomalies and underlying mechanisms involved using cardiac-specific overexpression of alcohol dehydrogenase (ADH.ADH and wild-type FVB mice were subjected to the ER stress inducer tunicamycin (1 mg/kg, i.p., for 48 hrs. Myocardial mechanical and intracellular Ca(2+ properties, ER stress, autophagy and associated cell signaling molecules were evaluated.ER stress compromised cardiac contractile function (evidenced as reduced fractional shortening, peak shortening, maximal velocity of shortening/relengthening, prolonged relengthening duration and impaired intracellular Ca(2+ homeostasis, oxidative stress and upregulated autophagy (increased LC3B, Atg5, Atg7 and p62, along with dephosphorylation of PTEN, Akt and mTOR, all of which were attenuated by ADH. In vitro study revealed that ER stress-induced cardiomyocyte anomaly was abrogated by ADH overexpression or autophagy inhibition using 3-MA. Interestingly, the beneficial effect of ADH was obliterated by autophagy induction, inhibition of Akt and mTOR. ER stress also promoted phosphorylation of the stress signaling ERK and JNK, the effect of which was unaffected by ADH transgene.Taken together, these findings suggested that ADH protects against ER stress-induced cardiac anomalies possibly via attenuation of oxidative stress and PTEN/Akt/mTOR pathway-regulated autophagy.

  7. Direct Cardiac Reprogramming: Advances in Cardiac Regeneration

    Directory of Open Access Journals (Sweden)

    Olivia Chen

    2015-01-01

    Full Text Available Heart disease is one of the lead causes of death worldwide. Many forms of heart disease, including myocardial infarction and pressure-loading cardiomyopathies, result in irreversible cardiomyocyte death. Activated fibroblasts respond to cardiac injury by forming scar tissue, but ultimately this response fails to restore cardiac function. Unfortunately, the human heart has little regenerative ability and long-term outcomes following acute coronary events often include chronic and end-stage heart failure. Building upon years of research aimed at restoring functional cardiomyocytes, recent advances have been made in the direct reprogramming of fibroblasts toward a cardiomyocyte cell fate both in vitro and in vivo. Several experiments show functional improvements in mouse models of myocardial infarction following in situ generation of cardiomyocyte-like cells from endogenous fibroblasts. Though many of these studies are in an early stage, this nascent technology holds promise for future applications in regenerative medicine. In this review, we discuss the history, progress, methods, challenges, and future directions of direct cardiac reprogramming.

  8. Endoplasmic reticulum redox state is not perturbed by pharmacological or pathological endoplasmic reticulum stress in live pancreatic β-cells.

    Directory of Open Access Journals (Sweden)

    Irmgard Schuiki

    Full Text Available Accumulation of unfolded, misfolded and aggregated proteins in the endoplasmic reticulum (ER causes ER stress. ER stress can result from physiological situations such as acute increases in secretory protein biosynthesis or pathological conditions that perturb ER homeostasis such as alterations in the ER redox state. Here we monitored ER redox together with transcriptional output of the Unfolded Protein Response (UPR in INS-1 insulinoma cells stably expressing eroGFP (ER-redox-sensor and mCherry protein driven by a GRP78 promoter (UPR-sensor. Live cell imaging, flow cytometry and biochemical characterization were used to examine these parameters in response to various conditions known to induce ER stress. As expected, treatment of the cells with the reducing agent dithiothreitol caused a decrease in the oxidation state of the ER accompanied by an increase in XBP-1 splicing. Unexpectedly however, other treatments including tunicamycin, thapsigargin, DL-homocysteine, elevated free fatty acids or high glucose had essentially no influence on the ER redox state, despite inducing ER stress. Comparable results were obtained with dispersed rat islet cells expressing eroGFP. Thus, unlike in yeast cells, ER stress in pancreatic β-cells is not associated with a more reducing ER environment.

  9. CDIP1-BAP31 Complex Transduces Apoptotic Signals from Endoplasmic Reticulum to Mitochondria under Endoplasmic Reticulum Stress

    Directory of Open Access Journals (Sweden)

    Takushi Namba

    2013-10-01

    Full Text Available Resolved endoplasmic reticulum (ER stress response is essential for intracellular homeostatic balance, but unsettled ER stress can lead to apoptosis. Here, we show that a proapoptotic p53 target, CDIP1, acts as a key signal transducer of ER-stress-mediated apoptosis. We identify B-cell-receptor-associated protein 31 (BAP31 as an interacting partner of CDIP1. Upon ER stress, CDIP1 is induced and enhances an association with BAP31 at the ER membrane. We also show that CDIP1 binding to BAP31 is required for BAP31 cleavage upon ER stress and for BAP31-Bcl-2 association. The recruitment of Bcl-2 to the BAP31-CDIP1 complex, as well as CDIP1-dependent truncated Bid (tBid and caspase-8 activation, contributes to BAX oligomerization. Genetic knockout of CDIP1 in mice leads to impaired response to ER-stress-mediated apoptosis. Altogether, our data demonstrate that the CDIP1/BAP31-mediated regulation of mitochondrial apoptosis pathway represents a mechanism for establishing an ER-mitochondrial crosstalk for ER-stress-mediated apoptosis signaling.

  10. Adiponectin protects rat myocardium against chronic intermittent hypoxia-induced injury via inhibition of endoplasmic reticulum stress.

    Directory of Open Access Journals (Sweden)

    Wenxiao Ding

    Full Text Available Obstructive sleep apnea syndrome (OSAS is associated with many cardiovascular disorders such as heart failure, hypertension, atherosclerosis, and arrhythmia and so on. Of the many associated factors, chronic intermittent hypoxia (CIH in particular is the primary player in OSAS. To assess the effects of CIH on cardiac function secondary to OSAS, we established a model to study the effects of CIH on Wistar rats. Specifically, we examined the possible underlying cellular mechanisms of hypoxic tissue damage and the possible protective role of adiponectin against hypoxic insults. In the first treatment group, rats were exposed to CIH conditions (nadir O2, 5-6% for 8 hours/day, for 5 weeks. Subsequent CIH-induced cardiac dysfunction was measured by echocardiograph. Compared with the normal control (NC group, rats in the CIH-exposed group experienced elevated levels of left ventricular end-systolic dimension and left ventricular end-systolic volume and depressed levels of left ventricular ejection fraction and left ventricular fractional shortening (p<0.05. However, when adiponectin (Ad was added in CIH + Ad group, we saw a rescue in the elevations of the aforementioned left ventricular function (p<0.05. To assess critical cardiac injury, we detected myocardial apoptosis by Terminal deoxynucleotidyl transfer-mediated dUTP nick end-labeling (TUNEL analysis. It was showed that the apoptosis percentage in CIH group (2.948% was significantly higher than that in NC group (0.4167% and CIH + Ad group (1.219% (p<0.05. Protein expressions of cleaved caspase-3, cleaved caspase-9, and cleaved-caspase-12 validated our TUNEL results (p<0.05. Mechanistically, our results demonstrated that the proteins expressed with endoplasmic reticulum stress and the expression of reactive oxygen species (ROS were significantly elevated under CIH conditions, whereas Ad supplementation partially decreased them. Overall, our results suggested that Ad augmentation could improve CIH

  11. Lipolysis Response to Endoplasmic Reticulum Stress in Adipose Cells*

    Science.gov (United States)

    Deng, Jingna; Liu, Shangxin; Zou, Liangqiang; Xu, Chong; Geng, Bin; Xu, Guoheng

    2012-01-01

    In obesity and diabetes, adipocytes show significant endoplasmic reticulum (ER) stress, which triggers a series of responses. This study aimed to investigate the lipolysis response to ER stress in rat adipocytes. Thapsigargin, tunicamycin, and brefeldin A, which induce ER stress through different pathways, efficiently activated a time-dependent lipolytic reaction. The lipolytic effect of ER stress occurred with elevated cAMP production and protein kinase A (PKA) activity. Inhibition of PKA reduced PKA phosphosubstrates and attenuated the lipolysis. Although both ERK1/2 and JNK are activated during ER stress, lipolysis is partially suppressed by inhibiting ERK1/2 but not JNK and p38 MAPK and PKC. Thus, ER stress induces lipolysis by activating cAMP/PKA and ERK1/2. In the downstream lipolytic cascade, phosphorylation of lipid droplet-associated protein perilipin was significantly promoted during ER stress but attenuated on PKA inhibition. Furthermore, ER stress stimuli did not alter the levels of hormone-sensitive lipase and adipose triglyceride lipase but caused Ser-563 and Ser-660 phosphorylation of hormone-sensitive lipase and moderately elevated its translocation from the cytosol to lipid droplets. Accompanying these changes, total activity of cellular lipases was promoted to confer the lipolysis. These findings suggest a novel pathway of the lipolysis response to ER stress in adipocytes. This lipolytic activation may be an adaptive response that regulates energy homeostasis but with sustained ER stress challenge could contribute to lipotoxicity, dyslipidemia, and insulin resistance because of persistently accelerated free fatty acid efflux from adipocytes to the bloodstream and other tissues. PMID:22223650

  12. Full-length Ebola glycoprotein accumulates in the endoplasmic reticulum

    Directory of Open Access Journals (Sweden)

    Bhattacharyya Suchita

    2011-01-01

    Full Text Available Abstract The Filoviridae family comprises of Ebola and Marburg viruses, which are known to cause lethal hemorrhagic fever. However, there is no effective anti-viral therapy or licensed vaccines currently available for these human pathogens. The envelope glycoprotein (GP of Ebola virus, which mediates entry into target cells, is cytotoxic and this effect maps to a highly glycosylated mucin-like region in the surface subunit of GP (GP1. However, the mechanism underlying this cytotoxic property of GP is unknown. To gain insight into the basis of this GP-induced cytotoxicity, HEK293T cells were transiently transfected with full-length and mucin-deleted (Δmucin Ebola GP plasmids and GP localization was examined relative to the nucleus, endoplasmic reticulum (ER, Golgi, early and late endosomes using deconvolution fluorescent microscopy. Full-length Ebola GP was observed to accumulate in the ER. In contrast, GPΔmucin was uniformly expressed throughout the cell and did not localize in the ER. The Ebola major matrix protein VP40 was also co-expressed with GP to investigate its influence on GP localization. GP and VP40 co-expression did not alter GP localization to the ER. Also, when VP40 was co-expressed with the nucleoprotein (NP, it localized to the plasma membrane while NP accumulated in distinct cytoplasmic structures lined with vimentin. These latter structures are consistent with aggresomes and may serve as assembly sites for filoviral nucleocapsids. Collectively, these data suggest that full-length GP, but not GPΔmucin, accumulates in the ER in close proximity to the nuclear membrane, which may underscore its cytotoxic property.

  13. Preconditioning with endoplasmic reticulum stress ameliorates endothelial cell inflammation.

    Science.gov (United States)

    Leonard, Antony; Paton, Adrienne W; El-Quadi, Monaliza; Paton, James C; Fazal, Fabeha

    2014-01-01

    Endoplasmic Reticulum (ER) stress, caused by disturbance in ER homeostasis, has been implicated in several pathological conditions such as ischemic injury, neurodegenerative disorders, metabolic diseases and more recently in inflammatory conditions. Our present study aims at understanding the role of ER stress in endothelial cell (EC) inflammation, a critical event in the pathogenesis of acute lung injury (ALI). We found that preconditioning human pulmonary artery endothelial cells (HPAEC) to ER stress either by depleting ER chaperone and signaling regulator BiP using siRNA, or specifically cleaving (inactivating) BiP using subtilase cytotoxin (SubAB), alleviates EC inflammation. The two approaches adopted to abrogate BiP function induced ATF4 protein expression and the phosphorylation of eIF2α, both markers of ER stress, which in turn resulted in blunting the activation of NF-κB, and restoring endothelial barrier integrity. Pretreatment of HPAEC with BiP siRNA inhibited thrombin-induced IκBα degradation and its resulting downstream signaling pathway involving NF-κB nuclear translocation, DNA binding, phosphorylation at serine536, transcriptional activation and subsequent expression of adhesion molecules. However, TNFα-mediated NF-κB signaling was unaffected upon BiP knockdown. In an alternative approach, SubAB-mediated inactivation of NF-κB was independent of IκBα degradation. Mechanistic analysis revealed that pretreatment of EC with SubAB interfered with the binding of the liberated NF-κB to the DNA, thereby resulting in reduced expression of adhesion molecules, cytokines and chemokines. In addition, both knockdown and inactivation of BiP stimulated actin cytoskeletal reorganization resulting in restoration of endothelial permeability. Together our studies indicate that BiP plays a central role in EC inflammation and injury via its action on NF-κB activation and regulation of vascular permeability.

  14. The Role of Endoplasmic Reticulum Stress in Diabetic Nephropathy.

    Science.gov (United States)

    Fan, Ying; Lee, Kyung; Wang, Niansong; He, John Cijiang

    2017-03-01

    Diabetic nephropathy (DN) has become the leading cause of end-stage renal disease (ESRD) worldwide. Accumulating evidence suggests that endoplasmic reticulum (ER) stress plays a major role in the development and progression of DN. Recent findings suggested that many attributes of DN, such as hyperglycemia, proteinuria, and increased advanced glycation end products and free fatty acids, can all trigger unfolded protein response (UPR) in kidney cells. Herein, we review the current knowledge on the role of ER stress in the setting of kidney injury with a specific emphasis on DN. As maladaptive ER stress response caused by excessively prolonged UPR will eventually cause cell death and increase kidney injury, several ER stress inhibitors have been shown to improve DN in animal models, albeit blocking both adaptive and maladaptive UPR. More recently, reticulon-1A (RTN1A), an ER-associated protein, was shown to be increased in both human and mouse diabetic kidneys. Its expression correlates with the progression of DN, and its polymorphisms are associated with kidney disease in people with diabetes. Increased RTN1A expression heightened the ER stress response and renal cell apoptosis, and conversely reduced RTN1A in renal cells decreased apoptosis and ameliorated kidney injury and DN progression, suggesting that RTN1A may be a novel target to specifically restrain the maladaptive UPR. These findings suggest that ER stress response in renal cells is a key driver of progression of DN and that the inhibition of the unchecked ER stress response in DN, such as by inhibition of RTN1A function, may be a promising therapeutic approach against DN.

  15. The role of endoplasmic reticulum stress in hippocampal insulin resistance.

    Science.gov (United States)

    Sims-Robinson, Catrina; Bakeman, Anna; Glasser, Rebecca; Boggs, Janet; Pacut, Crystal; Feldman, Eva L

    2016-03-01

    Metabolic syndrome, which includes hypertension, hyperglycemia, obesity, insulin resistance, and dyslipidemia, has a negative impact on cognitive health. Endoplasmic reticulum (ER) stress is activated during metabolic syndrome, however it is not known which factor associated with metabolic syndrome contributes to this stress. ER stress has been reported to play a role in the development of insulin resistance in peripheral tissues. The role of ER stress in the development of insulin resistance in hippocampal neurons is not known. In the current study, we investigated ER stress in the hippocampus of 3 different mouse models of metabolic syndrome: the C57BL6 mouse on a high fat (HF) diet; apolipoprotein E, leptin, and apolipoprotein B-48 deficient (ApoE 3KO) mice; and the low density lipoprotein receptor, leptin, and apolipoprotein B-48 deficient (LDLR 3KO) mice. We demonstrate that ER stress is activated in the hippocampus of HF mice, and for the first time, in ApoE 3KO mice, but not LDLR 3KO mice. The HF and ApoE 3KO mice are hyperglycemic; however, the LDLR 3KO mice have normal glycemia. This suggests that hyperglycemia may play a role in the activation of ER stress in the hippocampus. Similarly, we also demonstrate that impaired insulin signaling is only present in the HF and ApoE 3KO mice, which suggests that ER stress may play a role in insulin resistance in the hippocampus. To confirm this we pharmacologically induced ER stress with thapsigargin in human hippocampal neurons. We demonstrate for the first time that thapsigargin leads to ER stress and impaired insulin signaling in human hippocampal neurons. Our results may provide a potential mechanism that links metabolic syndrome and cognitive health. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Cardiac radiology: centenary review.

    Science.gov (United States)

    de Roos, Albert; Higgins, Charles B

    2014-11-01

    During the past century, cardiac imaging technologies have revolutionized the diagnosis and treatment of acquired and congenital heart disease. Many important contributions to the field of cardiac imaging were initially reported in Radiology. The field developed from the early stages of cardiac imaging, including the use of coronary x-ray angiography and roentgen kymography, to nowadays the widely used echocardiographic, nuclear medicine, cardiac computed tomographic (CT), and magnetic resonance (MR) applications. It is surprising how many of these techniques were not recognized for their potential during their early inception. Some techniques were described in the literature but required many years to enter the clinical arena and presently continue to expand in terms of clinical application. The application of various CT and MR contrast agents for the diagnosis of myocardial ischemia is a case in point, as the utility of contrast agents continues to expand the noninvasive characterization of myocardium. The history of cardiac imaging has included a continuous process of advances in our understanding of the anatomy and physiology of the cardiovascular system, along with advances in imaging technology that continue to the present day.

  17. Endoplasmic reticulum stress in pathogenesis of diabetic retinopathy and effect of calcium dobesilate

    Institute of Scientific and Technical Information of China (English)

    Yu-Min Gui; Ming Zhao; Jie Ding

    2016-01-01

    Objective:To study the mechanism of endoplasmic reticulum stress in the pathogenesis of diabetic retinopathy and effect of calcium dobesilate.Methods:A total of 120 diabetic retinopathy patients treated in our hospital from January 2010 to September 2015 were enrolled in this article. The serum endoplasmic reticulum stress protein and interleukin protein expression levels were analyzed before and after calcium dobesilate treatment. A total of 55 cases of healthy subjects receiving physical examination in our hospital during the same period were taken as control group.Results:Serum endoplasmic reticulum stress proteins PERK, CHOP and IRE as well as interleukin proteins IL1, IL2, IL6 and IL10 expression significantly increased, serum MDA level significantly increased while SOD, CAT and GSHpx levels significantly decreased in diabetic retinopathy patients, and compared with control group (P<0.01); after calcium dobesilate treatment, above factors were significantly restored (P<0.01).Conclusions: Diabetic retinopathy is closely related to endoplasmic reticulum stress and calcium dobesilate treatment may improve diabetic retinopathy by inhibiting endoplasmic reticulum stress.

  18. Isolated Cardiac Hydatid Cyst

    International Nuclear Information System (INIS)

    Shakil, U.; Rehman, A. U.; Shahid, R.

    2015-01-01

    Hydatid cyst disease is common in our part of the world. Cardiac hydatid cyst is its rare manifestation. We report this case of 48-year male having isolated cardiac hydatid cyst, incidentally found on computed tomography. This patient presented in medical OPD of Combined Military Hospital, Lahore with one month history of mild retrosternal discomfort. His general physical and systemic examinations as well as ECG were unremarkable. Chest X-ray showed an enlarged cardiac shadow with mildly irregular left heart border. Contrast enhanced CT scan of the chest showed a large well defined multiloculated non-enhancing cystic lesion with multiple daughter cysts involving wall of left ventricle and overlying pericardium. Serology for echinococcus confirmed the diagnosis of hydatid cyst. Patient was offered the surgical treatment but he opted for medical treatment only. Albendezol was prescribed. His follow-up echocardiography after one month showed no significant decrease in size of the cyst. (author)

  19. Pediatric cardiac postoperative care

    Directory of Open Access Journals (Sweden)

    Auler Jr. José Otávio Costa

    2002-01-01

    Full Text Available The Heart Institute of the University of São Paulo, Medical School is a referral center for the treatment of congenital heart diseases of neonates and infants. In the recent years, the excellent surgical results obtained in our institution may be in part due to modern anesthetic care and to postoperative care based on well-structured protocols. The purpose of this article is to review unique aspects of neonate cardiovascular physiology, the impact of extracorporeal circulation on postoperative evolution, and the prescription for pharmacological support of acute cardiac dysfunction based on our cardiac unit protocols. The main causes of low cardiac output after surgical correction of heart congenital disease are reviewed, and methods of treatment and support are proposed as derived from the relevant literature and our protocols.

  20. Quantitative cardiac computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Thelen, M.; Dueber, C.; Wolff, P.; Erbel, R.; Hoffmann, T.

    1985-06-01

    The scope and limitations of quantitative cardiac CT have been evaluated in a series of experimental and clinical studies. The left ventricular muscle mass was estimated by computed tomography in 19 dogs (using volumetric methods, measurements in two axes and planes and reference volume). There was good correlation with anatomical findings. The enddiastolic volume of the left ventricle was estimated in 22 patients with cardiomyopathies; using angiography as a reference, CT led to systematic under-estimation. It is also shown that ECG-triggered magnetic resonance tomography results in improved visualisation and may be expected to improve measurements of cardiac morphology.

  1. Cardiac output measurement

    Directory of Open Access Journals (Sweden)

    Andreja Möller Petrun

    2014-02-01

    Full Text Available In recent years, developments in the measuring of cardiac output and other haemodynamic variables are focused on the so-called minimally invasive methods. The aim of these methods is to simplify the management of high-risk and haemodynamically unstable patients. Due to the need of invasive approach and the possibility of serious complications the use of pulmonary artery catheter has decreased. This article describes the methods for measuring cardiac output, which are based on volume measurement (Fick method, indicator dilution method, pulse wave analysis, Doppler effect, and electrical bioimpedance.

  2. Silver nanoparticles induce endoplasmatic reticulum stress response in zebrafish

    Energy Technology Data Exchange (ETDEWEB)

    Christen, Verena [University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); Capelle, Martinus [Crucell, P.O. Box 2048, NL-2301 Leiden (Netherlands); Fent, Karl, E-mail: karl.fent@fhnw.ch [University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); Swiss Federal Institute of Technology Zürich, Department of Environmental Systems Science, CH-8092 Zürich (Switzerland)

    2013-10-15

    Silver nanoparticles (AgNPs) find increasing applications, and therefore humans and the environment are increasingly exposed to them. However, potential toxicological implications are not sufficiently known. Here we investigate effects of AgNPs (average size 120 nm) on zebrafish in vitro and in vivo, and compare them to human hepatoma cells (Huh7). AgNPs are incorporated in zebrafish liver cells (ZFL) and Huh7, and in zebrafish embryos. In ZFL cells AgNPs lead to induction of reactive oxygen species (ROS), endoplasmatic reticulum (ER) stress response, and TNF-α. Transcriptional alterations also occur in pro-apoptotic genes p53 and Bax. The transcriptional profile differed in ZFL and Huh7 cells. In ZFL cells, the ER stress marker BiP is induced, concomitant with the ER stress marker ATF-6 and spliced XBP-1 after 6 h and 24 h exposure to 0.5 g/L and 0.05 g/L AgNPs, respectively. This indicates the induction of different pathways of the ER stress response. Moreover, AgNPs induce TNF-α. In zebrafish embryos exposed to 0.01, 0.1, 1 and 5 mg/L AgNPs hatching was affected and morphological defects occurred at high concentrations. ER stress related gene transcripts BiP and Synv are significantly up-regulated after 24 h at 0.1 and 5 mg/L AgNPs. Furthermore, transcriptional alterations occurred in the pro-apoptotic genes Noxa and p21. The ER stress response was strong in ZFL cells and occurred in zebrafish embryos as well. Our data demonstrate for the first time that AgNPs lead to induction of ER stress in zebrafish. The induction of ER stress can have several consequences including the activation of apoptotic and inflammatory pathways. - Highlights: • Effects of silver nanoparticles (120 nm AgNPs) are investigated in zebrafish. • AgNPs induce all ER stress reponses in vitro in zebrafish liver cells. • AgNPs induce weak ER stress in zebrafish embryos. • AgNPs induce oxidative stress and transcripts of pro-apoptosis genes.

  3. Endoplasmic reticulum stress-mediated neuronal apoptosis by acrylamide exposure

    Energy Technology Data Exchange (ETDEWEB)

    Komoike, Yuta, E-mail: komoike@research.twmu.ac.jp; Matsuoka, Masato, E-mail: matsuoka@research.twmu.ac.jp

    2016-11-01

    Acrylamide (AA) is a well-known neurotoxic compound in humans and experimental animals. However, intracellular stress signaling pathways responsible for the neurotoxicity of AA are still not clear. In this study, we explored the involvement of the endoplasmic reticulum (ER) stress response in AA-induced neuronal damage in vitro and in vivo. Exposure of SH-SY5Y human neuroblastoma cells to AA increased the levels of phosphorylated form of eukaryotic translation initiation factor 2α (eIF2α) and its downstream effector, activating transcription factor 4 (ATF4), indicating the induction of the unfolded protein response (UPR) by AA exposure. Furthermore, AA exposure increased the mRNA level of c/EBP homologous protein (CHOP), the ER stress-dependent apoptotic factor, and caused the accumulation of reactive oxygen species (ROS) in SH-SY5Y cells. Treatments of SH-SY5Y cells with the chemical chaperone, 4-phenylbutyric acid and the ROS scavenger, N-acetyl-cysteine reduced the AA-induced expression of ATF4 protein and CHOP mRNA, and resulted in the suppression of apoptosis. In addition, AA-induced eIF2α phosphorylation was also suppressed by NAC treatment. In consistent with in vitro study, exposure of zebrafish larvae at 6-day post fertilization to AA induced the expression of chop mRNA and apoptotic cell death in the brain, and also caused the disruption of brain structure. These findings suggest that AA exposure induces apoptotic neuronal cell death through the ER stress and subsequent eIF2α–ATF4–CHOP signaling cascade. The accumulation of ROS by AA exposure appears to be responsible for this ER stress-mediated apoptotic pathway. - Highlights: • Exposure of SH-SY5Y cells to AA activates the eIF2α–ATF4 pathway of the UPR. • Exposure of SH-SY5Y cells to AA induces the CHOP expression and apoptosis. • Exposure of zebrafish to AA induces the chop expression and apoptosis in the brain. • AA possibly induces apoptotic neuronal cell death through the ER

  4. Silver nanoparticles induce endoplasmatic reticulum stress response in zebrafish

    International Nuclear Information System (INIS)

    Christen, Verena; Capelle, Martinus; Fent, Karl

    2013-01-01

    Silver nanoparticles (AgNPs) find increasing applications, and therefore humans and the environment are increasingly exposed to them. However, potential toxicological implications are not sufficiently known. Here we investigate effects of AgNPs (average size 120 nm) on zebrafish in vitro and in vivo, and compare them to human hepatoma cells (Huh7). AgNPs are incorporated in zebrafish liver cells (ZFL) and Huh7, and in zebrafish embryos. In ZFL cells AgNPs lead to induction of reactive oxygen species (ROS), endoplasmatic reticulum (ER) stress response, and TNF-α. Transcriptional alterations also occur in pro-apoptotic genes p53 and Bax. The transcriptional profile differed in ZFL and Huh7 cells. In ZFL cells, the ER stress marker BiP is induced, concomitant with the ER stress marker ATF-6 and spliced XBP-1 after 6 h and 24 h exposure to 0.5 g/L and 0.05 g/L AgNPs, respectively. This indicates the induction of different pathways of the ER stress response. Moreover, AgNPs induce TNF-α. In zebrafish embryos exposed to 0.01, 0.1, 1 and 5 mg/L AgNPs hatching was affected and morphological defects occurred at high concentrations. ER stress related gene transcripts BiP and Synv are significantly up-regulated after 24 h at 0.1 and 5 mg/L AgNPs. Furthermore, transcriptional alterations occurred in the pro-apoptotic genes Noxa and p21. The ER stress response was strong in ZFL cells and occurred in zebrafish embryos as well. Our data demonstrate for the first time that AgNPs lead to induction of ER stress in zebrafish. The induction of ER stress can have several consequences including the activation of apoptotic and inflammatory pathways. - Highlights: • Effects of silver nanoparticles (120 nm AgNPs) are investigated in zebrafish. • AgNPs induce all ER stress reponses in vitro in zebrafish liver cells. • AgNPs induce weak ER stress in zebrafish embryos. • AgNPs induce oxidative stress and transcripts of pro-apoptosis genes

  5. Role of endoplasmic reticulum stress in the loss of retinal ganglion cells in diabetic retinopathy

    Institute of Scientific and Technical Information of China (English)

    Liping Yang; Lemeng Wu; Dongmei Wang; Ying Li; Hongliang Dou; Mark OMTso; Zhizhong Ma

    2013-01-01

    Endoplasmic reticulum stress is closely involved in the early stage of diabetic retinopathy. In the present study, a streptozotocin-induced diabetic animal model was given an intraperitoneal injection of tauroursodeoxycholic acid. Results from immunofluorescent co-localization experiments showed that both caspase-12 protein and c-Jun N-terminal kinase 1 phosphorylation levels significantly in-creased, which was associated with retinal ganglion celldeath in diabetic retinas. The C/ERB ho-mologous protein pathway directly contributed to glial reactivity, and was subsequently responsible for neuronal loss and vascular abnormalities in diabetic retinopathy. Our experimental findings in-dicate that endoplasmic reticulum stress plays an important role in diabetes-induced retinal neu-ronal loss and vascular abnormalities, and that inhibiting the activation of the endoplasmic reticulum stress pathway provides effective protection against diabetic retinopathy.

  6. Immune responsiveness and incidence of reticulum cell sarcoma in long-term syngeneic radiation chimeras

    International Nuclear Information System (INIS)

    Adorini, L.; Gorini, G.; Covelli, V.; Ballardin, E.; di Michele, A.; Bassani, B.; Metalli, P.; Doria, G.

    1976-01-01

    Long-term syngeneic radiation chimeras displayed a very low incidence of reticulum cell sarcoma as compared with control mice. Immune reactivity of these animals was studied in vivo by anti-dinitrophenyl antibody titer and affinity and in vitro by mitotic responsiveness to phytohemagglutinin, concanavalin A and lipopolysaccharide. Antibody titer and affinity as well as the response to T lectins were found to be increased in chimeras. These results were attributed to increased function of mature T2 cells, which could explain the reduced incidence of reticulum cell sarcoma in chimeras

  7. Neonatal cardiac emergencies

    African Journals Online (AJOL)

    flow) or require intervention (surgical or catheter) within the first ... Cardiac. History. Risk factors, e.g. meconium-stained liquor, prematurity, ... 'snowman' sign for supracardiac total anomalous pulmonary venous drainage (TAPVD), cardiomegaly with plethora for ... central cyanosis and on auscultation you hear no murmurs.

  8. Comparative cardiac imaging

    International Nuclear Information System (INIS)

    Brundage, B.H.

    1990-01-01

    This book is designed to compare all major cardiac imaging techniques. All major imaging techniques - including conventional angiography, digital angiography, echocardiography and Doppler imaging, conventional radioisotope techniques, computed tomography, and magnetic resonance imaging - are covered in this text as they apply to the major cardiovascular disorders. There is brief coverage of positron emission tomography and an extensive presentation of ultrafast computed tomography

  9. Advanced Cardiac Life Support.

    Science.gov (United States)

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document contains materials for an advanced college course in cardiac life support developed for the State of Iowa. The course syllabus lists the course title, hours, number, description, prerequisites, learning activities, instructional units, required text, six references, evaluation criteria, course objectives by units, course…

  10. Cardiac Pacemakers; Marcapasos Cardiacos

    Energy Technology Data Exchange (ETDEWEB)

    Fiandra, O [Universidad de la Republica, Facultad de Maedicina, Departamento de Cardiologia, Montevideo(Uruguay); Espasandin, W [Universidad de la Republica, Facultad de Medicina, Departamento de Cirugia Cardiaca, Montevideo (Uruguay); Fiandra, H [Instituto Nacional de Cirugia Cardiaca, Departamento de Hemodinamia y Marcapasos, Montevideo (Uruguay); and others

    1984-07-01

    A complete survey of physiological biophysical,clinical and engineering aspects of cardiac facing,including the history and an assessment of possible future developments.Among the topics studied are: pacemakers, energy search, heart stimulating with pacemakers ,mathematical aspects of the electric cardio stimulation chronic, pacemaker implants,proceeding,treatment and control.

  11. Nonexercise cardiac stress testing

    International Nuclear Information System (INIS)

    Vacek, J.L.; Baldwin, T.

    1989-01-01

    Many patients who require evaluation for coronary artery disease are unable to undergo exercise stress testing because of physiologic or psychological limitations. Drs Vacek and Baldwin describe three alternative methods for assessment of cardiac function in these patients, all of which have high levels of diagnostic sensitivity and specificity. 23 references

  12. Cardiac magnetic resonance imaging

    African Journals Online (AJOL)

    2011-03-06

    Mar 6, 2011 ... Cardiac magnetic resonance imaging. Cardiovascular magnetic resonance imaging is becoming a routine diagnostic technique. BRUCE s sPOTTiswOOdE, PhD. MRC/UCT Medical Imaging Research Unit, University of Cape Town, and Division of Radiology, Stellenbosch University. Bruce Spottiswoode ...

  13. Maternal cardiac metabolism in pregnancy

    Science.gov (United States)

    Liu, Laura X.; Arany, Zolt

    2014-01-01

    Pregnancy causes dramatic physiological changes in the expectant mother. The placenta, mostly foetal in origin, invades maternal uterine tissue early in pregnancy and unleashes a barrage of hormones and other factors. This foetal ‘invasion’ profoundly reprogrammes maternal physiology, affecting nearly every organ, including the heart and its metabolism. We briefly review here maternal systemic metabolic changes during pregnancy and cardiac metabolism in general. We then discuss changes in cardiac haemodynamic during pregnancy and review what is known about maternal cardiac metabolism during pregnancy. Lastly, we discuss cardiac diseases during pregnancy, including peripartum cardiomyopathy, and the potential contribution of aberrant cardiac metabolism to disease aetiology. PMID:24448314

  14. Cardiac fusion and complex congenital cardiac defects in thoracopagus twins: diagnostic value of cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Goo, Hyun Woo [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea, Republic of); Park, Jeong-Jun [University of Ulsan College of Medicine, Asan Medical Center, Department of Pediatric Cardiac Surgery, Seoul (Korea, Republic of); Kim, Ellen Ai-Rhan [University of Ulsan College of Medicine, Asan Medical Center, Division of Neonatology, Department of Pediatrics, Seoul (Korea, Republic of); Won, Hye-Sung [University of Ulsan College of Medicine, Asan Medical Center, Department of Obstetrics and Gynecology, Seoul (Korea, Republic of)

    2014-09-15

    Most thoracopagus twins present with cardiac fusion and associated congenital cardiac defects, and assessment of this anatomy is of critical importance in determining patient care and outcome. Cardiac CT with electrocardiographic triggering provides an accurate and quick morphological assessment of both intracardiac and extracardiac structures in newborns, making it the best imaging modality to assess thoracopagus twins during the neonatal period. In this case report, we highlight the diagnostic value of cardiac CT in thoracopagus twins with an interatrial channel and complex congenital cardiac defects. (orig.)

  15. Ceramide transport from endoplasmic reticulum to Golgi apparatus is not vesicle-mediated

    NARCIS (Netherlands)

    Kok, JW; Babia, T; Klappe, K; Egea, G; Hoekstra, D

    1998-01-01

    Ceramide (Cer) transfer from the endoplasmic reticulum (ER) to the Golgi apparatus was measured under conditions that block vesicle-mediated protein transfer. This was done either in intact cells by reducing the incubation temperature to 15 degrees C, or in streptolysin O-permeabilized cells by

  16. Effects of ginger extract on smooth muscle activity of sheep reticulum and rumen

    Directory of Open Access Journals (Sweden)

    Amin Mamaghani

    2013-06-01

    Full Text Available Reticulorumen hypomotility leads to the impaired physiologic functions of the digestive tract. Prokinetic action of ginger has been demonstrated in the laboratory animals and human. The aim of this study was to evaluate the effect of hydroalcoholic extract of ginger on contraction and motility of reticulum and rumen of ruminants. Collected samples of reticulum and rumen from eight sheep were investigated in vitro. The extract at the concentration of 0.1 and 1.0 mg L-1 had no effect on any preparations. Contraction of reticulum and rumen preparations was occurred at 10.0 and 100 mg L-1 concentrations (p < 0.05. Concentration of 1000 mg L-1 caused a relaxation in preparations contracted with 10.0 and 100 mg L-1. Likewise, the concentration of 1000 mg L-1 significantly (p < 0.05 inhibited ACh-induced contraction in both tissues. Six sheep were involved in electromyographic study. Administration of 40 mg kg-1 of the extract increased the overall frequency of contractions of the reticulum and rumen at the subsequent three days with the prominent increase at the second day (p < 0.05. Results of in vitro study indicated that hydroalcoholic extract of ginger contained spasmogenic and spasmolytic constituents. The results in vivo study represented evidences that the extract may have stimulant effect on reticulorumen motility in 40 mg kg-1 concentration.

  17. A lentivirally delivered photoactivatable GFP to assess continuity in the endoplasmic reticulum of neurones and glia

    Czech Academy of Sciences Publication Activity Database

    Jones, V. C.; Rodríguez Arellano, Jose Julio; Verkhratsky, Alexei; Jones, O. T.

    2009-01-01

    Roč. 458, č. 4 (2009), s. 809-818 ISSN 0031-6768 R&D Projects: GA ČR GA305/08/1384 Institutional research plan: CEZ:AV0Z50390512 Keywords : endoplasmic reticulum * calcium store * neurone Subject RIV: FH - Neurology Impact factor: 3.695, year: 2009

  18. Regulation of calcium release from the endoplasmic reticulum by the serine hydrolase ABHD2.

    Science.gov (United States)

    Yun, Bogeon; Lee, HeeJung; Powell, Roger; Reisdorph, Nichole; Ewing, Heather; Gelb, Michael H; Hsu, Ku-Lung; Cravatt, Benjamin F; Leslie, Christina C

    2017-09-02

    The serine hydrolase inhibitors pyrrophenone and KT195 inhibit cell death induced by A23187 and H 2 O 2 by blocking the release of calcium from the endoplasmic reticulum and mitochondrial calcium uptake. The effect of pyrrophenone and KT195 on these processes is not due to inhibition of their known targets, cytosolic phospholipase A 2 and α/β-hydrolase domain-containing (ABHD) 6, respectively, but represent off-target effects. To identify targets of KT195, fibroblasts were treated with KT195-alkyne to covalently label protein targets followed by click chemistry with biotin azide, enrichment on streptavidin beads and tryptic peptide analysis by mass spectrometry. Although several serine hydrolases were identified, α/β-hydrolase domain-containing 2 (ABHD2) was the only target in which both KT195 and pyrrophenone competed for binding to KT195-alkyne. ABHD2 is a serine hydrolase with a predicted transmembrane domain consistent with its pull-down from the membrane proteome. Subcellular fractionation showed localization of ABHD2 to the endoplasmic reticulum but not to mitochondria or mitochondrial-associated membranes. Knockdown of ABHD2 with shRNA attenuated calcium release from the endoplasmic reticulum, mitochondrial calcium uptake and cell death in fibroblasts stimulated with A23187. The results describe a novel mechanism for regulating calcium transfer from the endoplasmic reticulum to mitochondria that involves the serine hydrolase ABHD2. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Chlorhexidine-induced apoptosis or necrosis in L929 fibroblasts: A role for endoplasmic reticulum stress

    International Nuclear Information System (INIS)

    Faria, Gisele; Cardoso, Cristina R.B.; Larson, Roy E.; Silva, Joao S.; Rossi, Marcos A.

    2009-01-01

    Chlorhexidine (CHX), widely used as antiseptic and therapeutic agent in medicine and dentistry, has a toxic effect both in vivo and in vitro. The intrinsic mechanism underlying CHX-induced cytotoxicity in eukaryotic cells is, however, still unknown. A recent study from our laboratory has suggested that CHX may induce death in cultured L929 fibroblasts via endoplasmic reticulum (ER) stress. This hypothesis was further tested by means of light and electron microscopy, quantification of apoptosis and necrosis by flow cytometry, fluorescence visualization of the cytoskeleton and endoplasmic reticulum, and evaluation of the expression of 78-kDa glucose-regulated protein 78 (Grp78), a marker of activation of the unfolded protein response (UPR) in cultured L929 fibroblasts. Our finding showing increased Grp 78 expression in CHX-treated cells and the results of flow cytometry, cytoskeleton and endoplasmic reticulum fluorescence visualization, and scanning and transmission electron microscopy allowed us to suggest that CHX elicits accumulation of proteins in the endoplasmic reticulum, which causes ER overload, resulting in ER stress and cell death either by necrosis or apoptosis. It must be pointed out, however, that this does not necessarily mean that ER stress is the only way that CHX kills L929 fibroblasts, but rather that ER stress is an important target or indicator of cell death induced by this drug

  20. The endoplasmic reticulum is a hub to sort proteins toward unconventional traffic pathways and endosymbiotic organelles.

    Science.gov (United States)

    Bellucci, Michele; De Marchis, Francesca; Pompa, Andrea

    2017-12-18

    The discovery that much of the extracellular proteome in eukaryotic cells consists of proteins lacking a signal peptide, which cannot therefore enter the secretory pathway, has led to the identification of alternative protein secretion routes bypassing the Golgi apparatus. However, proteins harboring a signal peptide for translocation into the endoplasmic reticulum can also be transported along these alternative routes, which are still far from being well elucidated in terms of the molecular machineries and subcellular/intermediate compartments involved. In this review, we first try to provide a definition of all the unconventional protein secretion pathways in eukaryotic cells, as those pathways followed by proteins directed to an 'external space' bypassing the Golgi, where 'external space' refers to the extracellular space plus the lumen of the secretory route compartments and the inner space of mitochondria and plastids. Then, we discuss the role of the endoplasmic reticulum in sorting proteins toward unconventional traffic pathways in plants. In this regard, various unconventional pathways exporting proteins from the endoplasmic reticulum to the vacuole, plasma membrane, apoplast, mitochondria, and plastids are described, including the short routes followed by the proteins resident in the endoplasmic reticulum. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  1. Socially differentiated cardiac rehabilitation

    DEFF Research Database (Denmark)

    Meillier, Lucette Kirsten; Nielsen, Kirsten Melgaard; Larsen, Finn Breinholt

    2012-01-01

    in recruitment and participation among low educated and socially vulnerable patients must be addressed to lower inequality in post-MI health. Our aim was to improve referral, attendance, and adherence rates among socially vulnerable patients by systematic screening and by offering a socially differentiated...... to a standard rehabilitation programme (SRP). If patients were identified as socially vulnerable, they were offered an extended version of the rehabilitation programme (ERP). Excluded patients were offered home visits by a cardiac nurse. Concordance principles were used in the individualised programme elements......%. Patients were equally distributed to the SRP and the ERP. No inequality was found in attendance and adherence among referred patients. Conclusions: It seems possible to overcome unequal referral, attendance, and adherence in cardiac rehabilitation by organisation of systematic screening and social...

  2. Ictal Cardiac Ryhthym Abnormalities.

    Science.gov (United States)

    Ali, Rushna

    2016-01-01

    Cardiac rhythm abnormalities in the context of epilepsy are a well-known phenomenon. However, they are under-recognized and often missed. The pathophysiology of these events is unclear. Bradycardia and asystole are preceded by seizure onset suggesting ictal propagation into the cortex impacting cardiac autonomic function, and the insula and amygdala being possible culprits. Sudden unexpected death in epilepsy (SUDEP) refers to the unanticipated death of a patient with epilepsy not related to status epilepticus, trauma, drowning, or suicide. Frequent refractory generalized tonic-clonic seizures, anti-epileptic polytherapy, and prolonged duration of epilepsy are some of the commonly identified risk factors for SUDEP. However, the most consistent risk factor out of these is an increased frequency of generalized tonic-clonic seizures (GTC). Prevention of SUDEP is extremely important in patients with chronic, generalized epilepsy. Since increased frequency of GTCS is the most consistently reported risk factor for SUDEP, effective seizure control is the most important preventive strategy.

  3. Fetal cardiac assessment

    International Nuclear Information System (INIS)

    Greene, K.R.

    1983-01-01

    The better understanding of fetal cardiovascular physiology coupled with improved technology for non-invasive study of the fetus now enable much more detailed assessment of fetal cardiac status than by heart rate alone. Even the latter, relatively simple, measurement contains much more information than was previously realized. It is also increasingly clear that no single measurement will provide the answer to all clinical dilemmas either on cardiac function or the welfare of the fetus as a whole. There are obvious clinical advantages in measuring several variables from one signal and the measurement of heart rate, heart rate variation and waveform from the ECG in labour is a potentially useful combination. Systolic time intervals or flow measurements could easily be added or used separately by combining real-time and Doppler ultrasound probes

  4. Cardiac nuclear medicine

    Energy Technology Data Exchange (ETDEWEB)

    Gerson, M.C.

    1987-01-01

    The book begins with a review of the radionuclide methods available for evaluating cardiac perfusion and function. The authors discuss planar and tomographic thallium myocardial imaging, first-pass and equilibrium radionuclide angiography, and imaging with infarct-avid tracers. Several common but more specialized procedures are then reviewed: nonogemetric measurement of left ventricular volume, phase (Fourier) analysis, stroke volume ratio, right ventricular function, and diastolic function. A separate chapter is devoted to drug interventions and in particular the use of radionuclide ventriculography to monitor doxorubicin toxicity and therapy of congestive heart failure. The subsequent chapters provide a comprehensive guide to test selection, accuracy, and results in acute myocardial infarction, in postmyocardial infarction, in chronic coronary artery disease, before and after medical or surgical revascularization, in valvular heart disease, in cardiomyopathies, and in cardiac trauma.

  5. Cardiac nuclear medicine

    International Nuclear Information System (INIS)

    Gerson, M.C.

    1987-01-01

    The book begins with a review of the radionuclide methods available for evaluating cardiac perfusion and function. The authors discuss planar and tomographic thallium myocardial imaging, first-pass and equilibrium radionuclide angiography, and imaging with infarct-avid tracers. Several common but more specialized procedures are then reviewed: nonogemetric measurement of left ventricular volume, phase (Fourier) analysis, stroke volume ratio, right ventricular function, and diastolic function. A separate chapter is devoted to drug interventions and in particular the use of radionuclide ventriculography to monitor doxorubicin toxicity and therapy of congestive heart failure. The subsequent chapters provide a comprehensive guide to test selection, accuracy, and results in acute myocardial infarction, in postmyocardial infarction, in chronic coronary artery disease, before and after medical or surgical revascularization, in valvular heart disease, in cardiomyopathies, and in cardiac trauma

  6. Cardiac function studies

    International Nuclear Information System (INIS)

    Horn, H.J.

    1986-01-01

    A total of 27 patients were subjected tointramyocardial sequential scintiscanning (first pass) using 99m-Tc human serum albumin. A refined method is described that is suitable to analyse clinically relevant parameters like blood volume, cardiac output, ejection fraction, stroke volume, enddiastolic and endsystolic volumes as well as pulmonal transition time and uses a complete camaracomputer system adapted to the requirements of a routine procedure. Unless there is special hardware available, the method does not yet appear mature enough to be put into general practice. Its importance recently appeared in a new light due to the advent of particularly shortlived isotopes. For the time being, however, ECG-triggered equilibrium studies are to be preferred for cardiac function tests. (TRV) [de

  7. CSI cardiac prevent 2015

    OpenAIRE

    S Ramakrishnan; Manisha Kaushik

    2015-01-01

    The CSI Cardiac Prevent 2015 was held at Hotel Taj Palace, New Delhi, on September 25-27, 2015. The major challenge was to create interest among cardiologists and physicians on preventive cardiology, a neglected area. The theme of the conference was "Innovations in Heart Disease Prevention.′′ This conference included "CSI at WHF Roadmap Workshop, Inauguration Ceremony, scientific program, plenary sessions, Nursing/Dietician track, Industry Exhibition, Social Events," Great India blood pressur...

  8. Multifractality in Cardiac Dynamics

    Science.gov (United States)

    Ivanov, Plamen Ch.; Rosenblum, Misha; Stanley, H. Eugene; Havlin, Shlomo; Goldberger, Ary

    1997-03-01

    Wavelet decomposition is used to analyze the fractal scaling properties of heart beat time series. The singularity spectrum D(h) of the variations in the beat-to-beat intervals is obtained from the wavelet transform modulus maxima which contain information on the hierarchical distribution of the singularities in the signal. Multifractal behavior is observed for healthy cardiac dynamics while pathologies are associated with loss of support in the singularity spectrum.

  9. Integrative Cardiac Health Project

    Science.gov (United States)

    2014-10-01

    primary cardiac arrest. Circulation. 1998;97(2):155Y160. 8. Sesso HD, Lee IM, Gaziano JM, Rexrode KM, Glynn RJ, Buring JE. Maternal and paternal ...to signal transduction, inflammation, and host–pathogen interactions .27 Whole blood RNA isolation systems such as PAXgene accurately capture in vivo...the effect of healthy behaviors on leukocyte function and leukocyte–endothelium interactions that are important for cardiovascular health

  10. Molecular nuclear cardiac imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong Soo; Paeng, Jin Chul [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of)

    2004-04-01

    Molecular nuclear cardiac imaging has included Tc-99m Annexin imaging to visualize myocardial apoptosis, but is now usually associated with gene therapy and cell-based therapy. Cardiac gene therapy was not successful so far but cardiac reporter gene imaging was made possible using HSV-TK (herpes simplex virus thymidine kinase) and F-18 FHBG (fluoro-hydroxymethylbutyl guanine) or I-124 FIAU (fluoro-deoxyiodo-arabino-furanosyluracil). Gene delivery was performed by needle injection with or without catheter guidance. TK expression did not last longer than 2 weeks in myocardium. Cell-based therapy of ischemic heart or failing heart looks promising, but biodistribution and differentiation of transplanted cells are not known. Reporter genes can be transfected to the stem/progenitor cells and cells containing these genes can be transplanted to the recipients using catheter-based purging or injection. Repeated imaging should be available and if promoter are varied to let express reporter transgenes, cellular (trans)differentiation can be studied. NIS (sodium iodide symporter) or D2R receptor genes are promising in this aspect.

  11. Cardiac hybrid imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gaemperli, Oliver [University Hospital Zurich, Cardiac Imaging, Zurich (Switzerland); University Hospital Zurich, Nuclear Cardiology, Cardiovascular Center, Zurich (Switzerland); Kaufmann, Philipp A. [University Hospital Zurich, Cardiac Imaging, Zurich (Switzerland); Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland)

    2014-05-15

    Hybrid cardiac single photon emission computed tomography (SPECT)/CT imaging allows combined assessment of anatomical and functional aspects of cardiac disease. In coronary artery disease (CAD), hybrid SPECT/CT imaging allows detection of coronary artery stenosis and myocardial perfusion abnormalities. The clinical value of hybrid imaging has been documented in several subsets of patients. In selected groups of patients, hybrid imaging improves the diagnostic accuracy to detect CAD compared to the single imaging techniques. Additionally, this approach facilitates functional interrogation of coronary stenoses and guidance with regard to revascularization procedures. Moreover, the anatomical information obtained from CT coronary angiography or coronary artery calcium scores (CACS) adds prognostic information over perfusion data from SPECT. The use of cardiac hybrid imaging has been favoured by the dissemination of dedicated hybrid systems and the release of dedicated image fusion software, which allow simple patient throughput for hybrid SPECT/CT studies. Further technological improvements such as more efficient detector technology to allow for low-radiation protocols, ultra-fast image acquisition and improved low-noise image reconstruction algorithms will be instrumental to further promote hybrid SPECT/CT in research and clinical practice. (orig.)

  12. Cardiac Cachexia Syndrome

    Directory of Open Access Journals (Sweden)

    Teresa Raposo André

    2017-10-01

    Full Text Available Heart failure is a chronic, progressive, and incurable disease. Cardiac cachexia is a strong predictor of poor prognosis, regardless of other important variables. This review intends to gather evidence to enable recognition of cardiac cachexia, identification of early stages of muscle waste and sarcopenia, and improve identification of patients with terminal heart failure in need of palliative care, whose symptoms are no longer controlled by usual medical measures. The pathophysiology is complex and multifactorial. There are many treatment options to prevent or revert muscle waste and sarcopenia; although, these strategies are less effective in advanced stages of cardiac cachexia. In these final stages, symptomatic palliation plays an important role, focussing on the patient’s comfort and avoiding the ‘acute model’ treatment of aggressive, disproportionate, and inefficient care. In order to provide adequate care and attempt to prevent this syndrome, thus reducing its impact on healthcare, there should be improved communication between general practitioners, internal medicine physicians, cardiologists, and palliative care specialists since heart failure has an unforeseeable course and is associated with an increasing number of deaths and different levels of suffering.

  13. Cardiac tissue engineering

    Directory of Open Access Journals (Sweden)

    MILICA RADISIC

    2005-03-01

    Full Text Available We hypothesized that clinically sized (1-5 mm thick,compact cardiac constructs containing physiologically high density of viable cells (~108 cells/cm3 can be engineered in vitro by using biomimetic culture systems capable of providing oxygen transport and electrical stimulation, designed to mimic those in native heart. This hypothesis was tested by culturing rat heart cells on polymer scaffolds, either with perfusion of culture medium (physiologic interstitial velocity, supplementation of perfluorocarbons, or with electrical stimulation (continuous application of biphasic pulses, 2 ms, 5 V, 1 Hz. Tissue constructs cultured without perfusion or electrical stimulation served as controls. Medium perfusion and addition of perfluorocarbons resulted in compact, thick constructs containing physiologic density of viable, electromechanically coupled cells, in contrast to control constructs which had only a ~100 mm thick peripheral region with functionally connected cells. Electrical stimulation of cultured constructs resulted in markedly improved contractile properties, increased amounts of cardiac proteins, and remarkably well developed ultrastructure (similar to that of native heart as compared to non-stimulated controls. We discuss here the state of the art of cardiac tissue engineering, in light of the biomimetic approach that reproduces in vitro some of the conditions present during normal tissue development.

  14. Molecular nuclear cardiac imaging

    International Nuclear Information System (INIS)

    Lee, Dong Soo; Paeng, Jin Chul

    2004-01-01

    Molecular nuclear cardiac imaging has included Tc-99m Annexin imaging to visualize myocardial apoptosis, but is now usually associated with gene therapy and cell-based therapy. Cardiac gene therapy was not successful so far but cardiac reporter gene imaging was made possible using HSV-TK (herpes simplex virus thymidine kinase) and F-18 FHBG (fluoro-hydroxymethylbutyl guanine) or I-124 FIAU (fluoro-deoxyiodo-arabino-furanosyluracil). Gene delivery was performed by needle injection with or without catheter guidance. TK expression did not last longer than 2 weeks in myocardium. Cell-based therapy of ischemic heart or failing heart looks promising, but biodistribution and differentiation of transplanted cells are not known. Reporter genes can be transfected to the stem/progenitor cells and cells containing these genes can be transplanted to the recipients using catheter-based purging or injection. Repeated imaging should be available and if promoter are varied to let express reporter transgenes, cellular (trans)differentiation can be studied. NIS (sodium iodide symporter) or D2R receptor genes are promising in this aspect

  15. Tributyltin induces apoptotic signaling in hepatocytes through pathways involving the endoplasmic reticulum and mitochondria

    International Nuclear Information System (INIS)

    Grondin, Melanie; Marion, Michel; Denizeau, Francine; Averill-Bates, Diana A.

    2007-01-01

    Tri-n-butyltin is a widespread environmental toxicant, which accumulates in the liver. This study investigates whether tri-n-butyltin induces pro-apoptotic signaling in rat liver hepatocytes through pathways involving the endoplasmic reticulum and mitochondria. Tri-n-butyltin activated the endoplasmic reticulum pathway of apoptosis, which was demonstrated by the activation of the protease calpain, its translocation to the plasma membrane, followed by cleavage of the calpain substrates, cytoskeletal protein vinculin, and caspase-12. Caspase-12 is localized to the cytoplasmic side of the endoplasmic reticulum and is involved in apoptosis mediated by the endoplasmic reticulum. Tri-n-butyltin also caused translocation of the pro-apoptotic proteins Bax and Bad from the cytosol to mitochondria, as well as changes in mitochondrial membrane permeability, events which can activate the mitochondrial death pathway. Tri-n-butyltin induced downstream apoptotic events in rat hepatocytes at the nuclear level, detected by chromatin condensation and by confocal microscopy using acridine orange. We investigated whether the tri-n-butyltin-induced pro-apoptotic events in hepatocytes could be linked to perturbation of intracellular calcium homeostasis, using confocal microscopy. Tri-n-butyltin caused changes in intracellular calcium distribution, which were similar to those induced by thapsigargin. Calcium was released from a subcellular compartment, which is likely to be the endoplasmic reticulum, into the cytosol. Cytosolic acidification, which is known to trigger apoptosis, also occurred and involved the Cl - /HCO 3 - exchanger. Pro-apoptotic events in hepatocytes were inhibited by the calcium chelator, Bapta-AM, and by a calpain inhibitor, which suggests that changes in intracellular calcium homeostasis are involved in tri-n-butyltin-induced apoptotic signaling in rat hepatocytes

  16. Initial Efficacy of a Cardiac Rehabilitation Transition Program: Cardiac TRUST

    Science.gov (United States)

    Zullo, Melissa; Boxer, Rebecca; Moore, Shirley M.

    2012-01-01

    Patients recovering from cardiac events are increasingly using postacute care, such as home health care and skilled nursing facility services. The purpose of this pilot study was to test the initial efficacy, feasibility, and safety of a specially designed postacute care transitional rehabilitation intervention for cardiac patients. Cardiac Transitional Rehabilitation Using Self- Management Techniques (Cardiac TRUST) is a family-focused intervention that includes progressive low-intensity walking and education in self-management skills to facilitate recovery following a cardiac event. Using a randomized two-group design, exercise self-efficacy, steps walked, and participation in an outpatient cardiac rehabilitation program were compared in a sample of 38 older adults; 17 who received the Cardiac TRUST program and 21 who received usual care only. At discharge from postacute care, the intervention group had a trend for higher levels of self-efficacy for exercise outcomes (X=39.1, SD=7.4) than the usual care group (X=34.5; SD=7.0) (t-test 1.9, p=.06). During the 6 weeks following discharge, compared with the usual care group, the intervention group had more attendance in out-patient cardiac rehabilitation (33% compared to 11.8%, F=7.1, p=.03) and a trend toward more steps walked during the first week (X=1,307, SD=652 compared to X=782, SD=544, t-test 1.8, p=.07). The feasibility of the intervention was better for the home health participants than for those in the skilled nursing facility and there were no safety concerns. The provision of cardiac-focused rehabilitation during postacute care has the potential to bridge the gap in transitional services from hospitalization to outpatient cardiac rehabilitation for these patients at high risk for future cardiac events. Further evidence of the efficacy of Cardiac TRUST is warranted. PMID:22084960

  17. Computational Cardiac Modeling Reveals Mechanisms of Ventricular Arrhythmogenesis in Long QT Syndrome Type 8: CACNA1C R858H Mutation Linked to Ventricular Fibrillation

    Directory of Open Access Journals (Sweden)

    Jieyun Bai

    2017-10-01

    Full Text Available Functional analysis of the L-type calcium channel has shown that the CACNA1C R858H mutation associated with severe QT interval prolongation may lead to ventricular fibrillation (VF. This study investigated multiple potential mechanisms by which the CACNA1C R858H mutation facilitates and perpetuates VF. The Ten Tusscher-Panfilov (TP06 human ventricular cell models incorporating the experimental data on the kinetic properties of L-type calcium channels were integrated into one-dimensional (1D fiber, 2D sheet, and 3D ventricular models to investigate the pro-arrhythmic effects of CACNA1C mutations by quantifying changes in intracellular calcium handling, action potential profiles, action potential duration restitution (APDR curves, dispersion of repolarization (DOR, QT interval and spiral wave dynamics. R858H “mutant” L-type calcium current (ICaL augmented sarcoplasmic reticulum calcium content, leading to the development of afterdepolarizations at the single cell level and focal activities at the tissue level. It also produced inhomogeneous APD prolongation, causing QT prolongation and repolarization dispersion amplification, rendering R858H “mutant” tissue more vulnerable to the induction of reentry compared with other conditions. In conclusion, altered ICaL due to the CACNA1C R858H mutation increases arrhythmia risk due to afterdepolarizations and increased tissue vulnerability to unidirectional conduction block. However, the observed reentry is not due to afterdepolarizations (not present in our model, but rather to a novel blocking mechanism.

  18. Alterations in cardiac sarcolemmal Ca2+ pump activity during diabetes mellitus

    International Nuclear Information System (INIS)

    Heyliger, C.E.; Prakash, A.; McNeill, J.

    1987-01-01

    Diabetes mellitus is frequently associated with a primary cardiomyopathy. The mechanisms responsible for this heart disease are not clear, but an alteration in myocardial Ca 2+ transport is believed to be involved in its development. Even though sarcolemma plays a crucial role in cellular Ca 2+ transport, little appears to be known about its Ca 2+ transporting capability in the diabetic myocardium. In this regard, the authors have examined the status of the cardiac sarcolemmal Ca 2+ pump during diabetes mellitus. Purified sarcolemmal membranes were isolated from male Wistar diabetic rat hearts 8 wk after streptozotocin injection. Ca 2+ pump activity assessed by measuring its Ca 2+ -stimulated adenosine triphosphatase and Ca 2+ -uptake ability in the absence and presence of calmodulin was significantly depressed in the diabetic myocardium relative to controls. These results did not appear to have been influenced by the minimal sarcoplasmic reticular and mitochondrial contamination of this membrane preparation. Hence, it appears that the sarcolemmal Ca 2+ pump is defective in the diabetic myocardium and may be involved in the altered Ca 2+ transport of the heart during diabetes mellitus

  19. Sodium Butyrate Induces Endoplasmic Reticulum Stress and Autophagy in Colorectal Cells: Implications for Apoptosis.

    Directory of Open Access Journals (Sweden)

    Jintao Zhang

    Full Text Available Butyrate, a short-chain fatty acid derived from dietary fiber, inhibits proliferation and induces cell death in colorectal cancer cells. However, clinical trials have shown mixed results regarding the anti-tumor activities of butyrate. We have previously shown that sodium butyrate increases endoplasmic reticulum stress by altering intracellular calcium levels, a well-known autophagy trigger. Here, we investigated whether sodium butyrate-induced endoplasmic reticulum stress mediated autophagy, and whether there was crosstalk between autophagy and the sodium butyrate-induced apoptotic response in human colorectal cancer cells.Human colorectal cancer cell lines (HCT-116 and HT-29 were treated with sodium butyrate at concentrations ranging from 0.5-5mM. Cell proliferation was assessed using MTT tetrazolium salt formation. Autophagy induction was confirmed through a combination of Western blotting for associated proteins, acridine orange staining for acidic vesicles, detection of autolysosomes (MDC staining, and electron microscopy. Apoptosis was quantified by flow cytometry using standard annexinV/propidium iodide staining and by assessing PARP-1 cleavage by Western blot.Sodium butyrate suppressed colorectal cancer cell proliferation, induced autophagy, and resulted in apoptotic cell death. The induction of autophagy was supported by the accumulation of acidic vesicular organelles and autolysosomes, and the expression of autophagy-associated proteins, including microtubule-associated protein II light chain 3 (LC3-II, beclin-1, and autophagocytosis-associated protein (Atg3. The autophagy inhibitors 3-methyladenine (3-MA and chloroquine inhibited sodium butyrate induced autophagy. Furthermore, sodium butyrate treatment markedly enhanced the expression of endoplasmic reticulum stress-associated proteins, including BIP, CHOP, PDI, and IRE-1a. When endoplasmic reticulum stress was inhibited by pharmacological (cycloheximide and mithramycin and genetic

  20. Antifibrinolytics in cardiac surgery

    Directory of Open Access Journals (Sweden)

    Achal Dhir

    2013-01-01

    Full Text Available Cardiac surgery exerts a significant strain on the blood bank services and is a model example in which a multi-modal blood-conservation strategy is recommended. Significant bleeding during cardiac surgery, enough to cause re-exploration and/or blood transfusion, increases morbidity and mortality. Hyper-fibrinolysis is one of the important contributors to increased bleeding. This knowledge has led to the use of anti-fibrinolytic agents especially in procedures performed under cardiopulmonary bypass. Nothing has been more controversial in recent times than the aprotinin controversy. Since the withdrawal of aprotinin from the world market, the choice of antifibrinolytic agents has been limited to lysine analogues either tranexamic acid (TA or epsilon amino caproic acid (EACA. While proponents of aprotinin still argue against its non-availability. Health Canada has approved its use, albeit under very strict regulations. Antifibrinolytic agents are not without side effects and act like double-edged swords, the stronger the anti-fibrinolytic activity, the more serious the side effects. Aprotinin is the strongest in reducing blood loss, blood transfusion, and possibly, return to the operating room after cardiac surgery. EACA is the least effective, while TA is somewhere in between. Additionally, aprotinin has been implicated in increased mortality and maximum side effects. TA has been shown to increase seizure activity, whereas, EACA seems to have the least side effects. Apparently, these agents do not differentiate between pathological and physiological fibrinolysis and prevent all forms of fibrinolysis leading to possible thrombotic side effects. It would seem prudent to select the right agent knowing its risk-benefit profile for a given patient, under the given circumstances.

  1. Exercise-related cardiac arrest in cardiac rehabilitation - The ...

    African Journals Online (AJOL)

    Prescribed physical activity plays a major role in the rehabilitation of patients with coronary artery disease, and as with any other form of treatment its benefits must be weighed against its possible risks. This study attempted to establish the safety of cardiac rehabilitation as a medical intervention at the Johannesburg Cardiac ...

  2. Single ventricle cardiac defect

    International Nuclear Information System (INIS)

    Eren, B.; Turkmen, N.; Fedakar, R.; Cetin, V.

    2010-01-01

    Single ventricle heart is defined as a rare cardiac abnormality with a single ventricle chamber involving diverse functional and physiological defects. Our case is of a ten month-old baby boy who died shortly after admission to the hospital due to vomiting and diarrhoea. Autopsy findings revealed cyanosis of finger nails and ears. Internal examination revealed; large heart, weighing 60 grams, single ventricle, without a septum and upper membranous part. Single ventricle is a rare pathology, hence, this paper aims to discuss this case from a medico-legal point of view. (author)

  3. CSI cardiac prevent 2015

    Directory of Open Access Journals (Sweden)

    S Ramakrishnan

    2015-01-01

    Full Text Available The CSI Cardiac Prevent 2015 was held at Hotel Taj Palace, New Delhi, on September 25-27, 2015. The major challenge was to create interest among cardiologists and physicians on preventive cardiology, a neglected area. The theme of the conference was "Innovations in Heart Disease Prevention.′′ This conference included "CSI at WHF Roadmap Workshop, Inauguration Ceremony, scientific program, plenary sessions, Nursing/Dietician track, Industry Exhibition, Social Events," Great India blood pressure Survey, and CSI Smart Heart App. A total of 848 delegates/faculties attended this conference against a total of 1140 people registered for the meeting.

  4. Hypertension and Cardiac Arrhythmias

    DEFF Research Database (Denmark)

    Lip, Gregory Y H; Coca, Antonio; Kahan, Thomas

    2017-01-01

    Hypertension (HTN) is a common cardiovascular risk factor leading to heart failure (HF), coronary artery disease (CAD), stroke, peripheral artery disease and chronic renal failure. Hypertensive heart disease can manifest as many types of cardiac arrhythmias, most commonly being atrial fibrillation......) Council on Hypertension convened a Task Force, with representation from the Heart Rhythm Society (HRS), Asia-Pacific Heart Rhythm Society (APHRS), and Sociedad Latinoamericana de Estimulación Cardíaca y Electrofisiología (SOLEACE), with the remit of comprehensively reviewing the available evidence...

  5. Understanding Key Mechanisms of Exercise-Induced Cardiac Protection to Mitigate Disease: Current Knowledge and Emerging Concepts.

    Science.gov (United States)

    Bernardo, Bianca C; Ooi, Jenny Y Y; Weeks, Kate L; Patterson, Natalie L; McMullen, Julie R

    2018-01-01

    The benefits of exercise on the heart are well recognized, and clinical studies have demonstrated that exercise is an intervention that can improve cardiac function in heart failure patients. This has led to significant research into understanding the key mechanisms responsible for exercise-induced cardiac protection. Here, we summarize molecular mechanisms that regulate exercise-induced cardiac myocyte growth and proliferation. We discuss in detail the effects of exercise on other cardiac cells, organelles, and systems that have received less or little attention and require further investigation. This includes cardiac excitation and contraction, mitochondrial adaptations, cellular stress responses to promote survival (heat shock response, ubiquitin-proteasome system, autophagy-lysosomal system, endoplasmic reticulum unfolded protein response, DNA damage response), extracellular matrix, inflammatory response, and organ-to-organ crosstalk. We summarize therapeutic strategies targeting known regulators of exercise-induced protection and the challenges translating findings from bench to bedside. We conclude that technological advancements that allow for in-depth profiling of the genome, transcriptome, proteome and metabolome, combined with animal and human studies, provide new opportunities for comprehensively defining the signaling and regulatory aspects of cell/organelle functions that underpin the protective properties of exercise. This is likely to lead to the identification of novel biomarkers and therapeutic targets for heart disease.

  6. Cardiac Arrest: MedlinePlus Health Topic

    Science.gov (United States)

    ... Handouts Cardiac arrest (Medical Encyclopedia) Also in Spanish Topic Image MedlinePlus Email Updates Get Cardiac Arrest updates ... this? GO MEDICAL ENCYCLOPEDIA Cardiac arrest Related Health Topics Arrhythmia CPR Pacemakers and Implantable Defibrillators National Institutes ...

  7. Cardiac chamber scintiscanning

    International Nuclear Information System (INIS)

    Goretzki, G.

    1981-01-01

    The two methods of cardiac chamber scintiscanning, i.e. 'first pass' and 'ECG-triggered' examinations, are explained and compared. Two tables indicate the most significant radiation doses of the applied radio tracers, i.e. 99m-Tc-pertechnetate and 99m-Tc-HSA, to which a patient is exposed. These averaged values are calculated from various data given in specialised literature. On the basis of data given in literature, an effective half-life of approximately 5 hours in the intravascular space was calculated for the erythrocytes labelled with technetium 99m. On this basis, the radiation doses for the patients due to 99m-Tc-labelled erythrocytes are estimated. The advantages and disadvantages of the two methods applied for cardiac chamber scintiscanning are put into contrast and compared with the advantages and disadvantages of the quantitative X-ray cardiography of the left heart. The still existing problems connected with the assessment of ECG-triggered images are discussed in detail. The author performed investigations of his own, which concerned the above-mentioned problems. (orig./MG) [de

  8. Cardiac arrest – cardiopulmonary resuscitation

    Directory of Open Access Journals (Sweden)

    Basri Lenjani

    2014-01-01

    Conclusions: All survivors from cardiac arrest have received appropriate medical assistance within 10 min from attack, which implies that if cardiac arrest occurs near an institution health care (with an opportunity to provide the emergent health care the rate of survival is higher.

  9. Lentiginosis, Deafness and Cardiac Abnormalities*

    African Journals Online (AJOL)

    1973-01-06

    Jan 6, 1973 ... His height. mass. intelligence and genitalia were normal. The aSSOCiatIOn between deafness and disturbance of cardiac conduction and between pigmented skin lesions and cardiac abnormalities, has been well described. Should. ~I patient present with multiple lentigines and/or familial sensineural ...

  10. Health Instruction Packages: Cardiac Anatomy.

    Science.gov (United States)

    Phillips, Gwen; And Others

    Text, illustrations, and exercises are utilized in these five learning modules to instruct nurses, students, and other health care professionals in cardiac anatomy and functions and in fundamental electrocardiographic techniques. The first module, "Cardiac Anatomy and Physiology: A Review" by Gwen Phillips, teaches the learner to draw…

  11. Neuromuscular diseases after cardiac transplantation

    NARCIS (Netherlands)

    Mateen, Farrah J.; van de Beek, Diederik; Kremers, Walter K.; Daly, Richard C.; Edwards, Brooks S.; McGregor, Christopher G. A.; Wijdicks, Eelco F. M.

    2009-01-01

    BACKGROUND: Cardiac transplantation is a therapeutic option in end-stage heart failure. Peripheral nervous system (PNS) disease is known to occur in cardiac transplant recipients but has not been fully characterized. METHODS: This retrospective cohort review reports the PNS-related concerns of 313

  12. Hypokalemia and sudden cardiac death

    DEFF Research Database (Denmark)

    Kjeldsen, Keld

    2010-01-01

    Worldwide, approximately three million people suffer sudden cardiac death annually. These deaths often emerge from a complex interplay of substrates and triggers. Disturbed potassium homeostasis among heart cells is an example of such a trigger. Thus, hypokalemia and, also, more transient...... of fatal arrhythmia and sudden cardiac death a patient is, the more attention should be given to the potassium homeostasis....

  13. THE RESPONSE OF DISSEMINATED RETICULUM CELL SARCOMA TO THE INTRAVENOUS INJECTION OF COLLOIDAL RADIOACTIVE GOLD

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, Philip; Levitt, Seymour H.

    1963-06-15

    Case histories of two patients treated with colloidal radiogold for diffuse reticulum cell sarcoma are presented. Further analysis of the method is suggested by the unusually long survival time of one of the patients. It was concluded that, although external radiotherapy remains the treatment of choice in localized reticulum cell sarcoma, intravenous colloidal radiogold may be a useful agent in lymphosarcomas with diffuse minute neoplastic liver and spleen involvements. Intravenous colloidal radiogold can produce bone marrow depression and thrombocytopenia which can lead to death. This factor tends to argue against therapeutic use of the agent. It is suggested that no more than 50 mC Au/sup 198/ intravenously should be used for treatment of this disease. (R.M.G.)

  14. Sphingosine inhibits the sarco(endo)plasmic reticulum Ca"2"+-ATPase (SERCA) activity

    International Nuclear Information System (INIS)

    Benaim, Gustavo; Pimentel, Adriana A.; Felibertt, Pimali; Mayora, Adriana; Colman, Laura; Sojo, Felipe; Rojas, Héctor; De Sanctis, Juan B.

    2016-01-01

    The increase in the intracellular Ca"2"+ concentration ([Ca"2"+]_i) is the key variable for many different processes, ranging from regulation of cell proliferation to apoptosis. In this work we demonstrated that the sphingolipid sphingosine (Sph) increases the [Ca"2"+]_i by inhibiting the sarco(endo)plasmic reticulum Ca"2"+-ATPase (SERCA), in a similar manner to thapsigargin (Tg), a specific inhibitor of this Ca"2"+ pump. The results showed that addition of sphingosine produced a release of Ca"2"+ from the endoplasmic reticulum followed by a Ca"2"+ entrance from the outside mileu. The results presented in this work support that this sphingolipid could control the activity of the SERCA, and hence sphingosine may participate in the regulation of [Ca"2"+]_I in mammalian cells.

  15. Sphingosine inhibits the sarco(endo)plasmic reticulum Ca{sup 2+}-ATPase (SERCA) activity

    Energy Technology Data Exchange (ETDEWEB)

    Benaim, Gustavo, E-mail: gbenaim@idea.gob.ve [Instituto de Estudios Avanzados (IDEA), Caracas (Venezuela, Bolivarian Republic of); Instituto de Biología Experimental, Facultad de Ciencias, Universidad Central de Venezuela (UCV), Caracas (Venezuela, Bolivarian Republic of); Pimentel, Adriana A., E-mail: adriana.pimentel@ucv.ve [Facultad de Farmacia, Universidad Central de Venezuela (UCV), Caracas (Venezuela, Bolivarian Republic of); Felibertt, Pimali [Facultad de Ciencias, Universidad de Carabobo, Valencia (Venezuela, Bolivarian Republic of); Mayora, Adriana [Instituto de Biología Experimental, Facultad de Ciencias, Universidad Central de Venezuela (UCV), Caracas (Venezuela, Bolivarian Republic of); Colman, Laura [Instituto Pasteur de Montevideo, Montevideo (Uruguay); Sojo, Felipe [Instituto de Biología Experimental, Facultad de Ciencias, Universidad Central de Venezuela (UCV), Caracas (Venezuela, Bolivarian Republic of); Rojas, Héctor [Instituto de Inmunología, Universidad Central de Venezuela (UCV), Caracas (Venezuela, Bolivarian Republic of); Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas (Venezuela, Bolivarian Republic of); De Sanctis, Juan B. [Instituto de Inmunología, Universidad Central de Venezuela (UCV), Caracas (Venezuela, Bolivarian Republic of)

    2016-04-29

    The increase in the intracellular Ca{sup 2+} concentration ([Ca{sup 2+}]{sub i}) is the key variable for many different processes, ranging from regulation of cell proliferation to apoptosis. In this work we demonstrated that the sphingolipid sphingosine (Sph) increases the [Ca{sup 2+}]{sub i} by inhibiting the sarco(endo)plasmic reticulum Ca{sup 2+}-ATPase (SERCA), in a similar manner to thapsigargin (Tg), a specific inhibitor of this Ca{sup 2+} pump. The results showed that addition of sphingosine produced a release of Ca{sup 2+} from the endoplasmic reticulum followed by a Ca{sup 2+} entrance from the outside mileu. The results presented in this work support that this sphingolipid could control the activity of the SERCA, and hence sphingosine may participate in the regulation of [Ca{sup 2+}]{sub I} in mammalian cells.

  16. Organization of the cytoplasmic reticulum in the central vacuole of parenchyma cells in Allium cepa L.

    Directory of Open Access Journals (Sweden)

    Tomasz J. Wodzicki

    2015-01-01

    Full Text Available An elaborate and complex cytoplasmic reticulum composed of fine filaments and lamellae ranging from 0.1 to 4 microns in size is revealed by viewing the central vacuole of onion bulb parenchyma cells with the scanning election microscope. The larger cytoplasmic strands, visible with the light microscope, are composed of numerous smaller filaments (some tubular which might explain the observed bidirectional movement of particles in these larger strands. The finely divided cytoplasmic network of filaments is continuous with the parietal cytoplasm inclosing the vacuolar sap. In these highly vacuolated cells the mass of the protoplast is in the form of an intravacuolar reticulum immersed in the cell sap. The probable significance of the vacuolar sap in relation to physiological processes of the cell is discussed.

  17. A turn-on fluorescent probe for endogenous formaldehyde in the endoplasmic reticulum of living cells

    Science.gov (United States)

    Tang, Yonghe; Ma, Yanyan; Xu, An; Xu, Gaoping; Lin, Weiying

    2017-06-01

    As the simplest aldehyde compounds, formaldehyde (FA) is implicated in nervous system diseases and cancer. Endoplasmic reticulum is an organelle that plays important functions in living cells. Accordingly, the development of efficient methods for FA detection in the endoplasmic reticulum (ER) is of great biomedical importance. In this work, we developed the first ER-targeted fluorescent FA probe Na-FA-ER. The detection is based on the condensation reaction of the hydrazine group and FA to suppress the photo-induced electron transfer (PET) pathway, resulting in a fluorescence increase. The novel Na-FA-ER showed high sensitivity to FA. In addition, the Na-FA-ER enabled the bio-imaging of exogenous and endogenous FA in living HeLa cells. Most significantly, the new Na-FA-ER was employed to visualize the endogenous FA in the ER in living cells for the first time.

  18. Dual Role of Ancient Ubiquitous Protein 1 (AUP1) in Lipid Droplet Accumulation and Endoplasmic Reticulum (ER) Protein Quality Control

    OpenAIRE

    Klemm, Elizabeth J.; Spooner, Eric; Ploegh, Hidde L.

    2011-01-01

    Quality control of endoplasmic reticulum proteins involves the identification and engagement of misfolded proteins, dislocation of the misfolded protein across the endoplasmic reticulum (ER) membrane, and ubiquitin-mediated targeting to the proteasome for degradation. Ancient ubiquitous protein 1 (AUP1) physically associates with the mammalian HRD1-SEL1L complex, and AUP1 depletion impairs degradation of misfolded ER proteins. One of the functions of AUP1 in ER quality control is to recruit t...

  19. Titanium Dioxide Nanoparticles Induce Endoplasmic Reticulum Stress-Mediated Autophagic Cell Death via Mitochondria-Associated Endoplasmic Reticulum Membrane Disruption in Normal Lung Cells

    Science.gov (United States)

    Yu, Kyeong-Nam; Chang, Seung-Hee; Park, Soo Jin; Lim, Joohyun; Lee, Jinkyu; Yoon, Tae-Jong; Kim, Jun-Sung; Cho, Myung-Haing

    2015-01-01

    Nanomaterials are used in diverse fields including food, cosmetic, and medical industries. Titanium dioxide nanoparticles (TiO2-NP) are widely used, but their effects on biological systems and mechanism of toxicity have not been elucidated fully. Here, we report the toxicological mechanism of TiO2-NP in cell organelles. Human bronchial epithelial cells (16HBE14o-) were exposed to 50 and 100 μg/mL TiO2-NP for 24 and 48 h. Our results showed that TiO2-NP induced endoplasmic reticulum (ER) stress in the cells and disrupted the mitochondria-associated endoplasmic reticulum membranes (MAMs) and calcium ion balance, thereby increasing autophagy. In contrast, an inhibitor of ER stress, tauroursodeoxycholic acid (TUDCA), mitigated the cellular toxic response, suggesting that TiO2-NP promoted toxicity via ER stress. This novel mechanism of TiO2-NP toxicity in human bronchial epithelial cells suggests that further exhaustive research on the harmful effects of these nanoparticles in relevant organisms is needed for their safe application. PMID:26121477

  20. Cardiac changes in anorexia nervosa.

    Science.gov (United States)

    Spaulding-Barclay, Michael A; Stern, Jessica; Mehler, Philip S

    2016-04-01

    Introduction Anorexia nervosa is an eating disorder, which is associated with many different medical complications as a result of the weight loss and malnutrition that characterise this illness. It has the highest mortality rate of any psychiatric disorder. A large portion of deaths are attributable to the cardiac abnormalities that ensue as a result of the malnutrition associated with anorexia nervosa. In this review, the cardiac complications of anorexia nervosa will be discussed. A comprehensive literature review on cardiac changes in anorexia nervosa was carried out. There are structural, functional, and rhythm-type changes that occur in patients with anorexia nervosa. These become progressively significant as ongoing weight loss occurs. Cardiac changes are inherent to anorexia nervosa and they become more life-threatening and serious as the anorexia nervosa becomes increasingly severe. Weight restoration and attention to these cardiac changes are crucial for a successful treatment outcome.

  1. Biosynthesis of cardiac natriuretic peptides

    DEFF Research Database (Denmark)

    Goetze, Jens Peter

    2010-01-01

    Cardiac-derived peptide hormones were identified more than 25 years ago. An astonishing amount of clinical studies have established cardiac natriuretic peptides and their molecular precursors as useful markers of heart disease. In contrast to the clinical applications, the biogenesis of cardiac...... peptides has only been elucidated during the last decade. The cellular synthesis including amino acid modifications and proteolytic cleavages has proven considerably more complex than initially perceived. Consequently, the elimination phase of the peptide products in circulation is not yet well....... An inefficient post-translational prohormone maturation will also affect the biology of the cardiac natriuretic peptide system. This review aims at summarizing the myocardial synthesis of natriuretic peptides focusing on B-type natriuretic peptide, where new data has disclosed cardiac myocytes as highly...

  2. Endoplasmic Reticulum Stress-Associated Lipid Droplet Formation and Type II Diabetes

    OpenAIRE

    Zhang, Xuebao; Zhang, Kezhong

    2012-01-01

    Diabetes mellitus (DM), a metabolic disorder characterized by hyperglycemia, is caused by insufficient insulin production due to excessive loss of pancreatic β cells (type I diabetes) or impaired insulin signaling due to peripheral insulin resistance (type II diabetes). Pancreatic β cell is the only insulin-secreting cell type that has highly developed endoplasmic reticulum (ER) to cope with high demands of insulin synthesis and secretion. Therefore, ER homeostasis is crucial to the proper fu...

  3. Lipid Droplet Formation Is Dispensable for Endoplasmic Reticulum-associated Degradation*

    OpenAIRE

    Olzmann, James A.; Kopito, Ron R.

    2011-01-01

    Proteins that fail to fold or assemble in the endoplasmic reticulum (ER) are destroyed by cytoplasmic proteasomes through a process known as ER-associated degradation. Substrates of this pathway are initially sequestered within the ER lumen and must therefore be dislocated across the ER membrane to be degraded. It has been proposed that generation of bicellar structures during lipid droplet formation may provide an “escape hatch” through which misfolded proteins, toxins, and viruses can exit ...

  4. Respiratory metabolism and calorie restriction relieve persistent endoplasmic reticulum stress induced by calcium shortage in yeast

    OpenAIRE

    Busti, Stefano; Mapelli, Valeria; Tripodi, Farida; Sanvito, Rossella; Magni, Fulvio; Coccetti, Paola; Rocchetti, Marcella; Nielsen, Jens; Alberghina, Lilia; Vanoni, Marco

    2016-01-01

    Calcium homeostasis is crucial to eukaryotic cell survival. By acting as an enzyme cofactor and a second messenger in several signal transduction pathways, the calcium ion controls many essential biological processes. Inside the endoplasmic reticulum (ER) calcium concentration is carefully regulated to safeguard the correct folding and processing of secretory proteins. By using the model organism Saccharomyces cerevisiae we show that calcium shortage leads to a slowdown of cell growth and met...

  5. Psychological Stress, Cocaine and Natural Reward Each Induce Endoplasmic Reticulum Stress Genes in Rat Brain

    OpenAIRE

    Pavlovsky, Ashly A.; Boehning, Darren; Li, Dingge; Zhang, Yafang; Fan, Xiuzhen; Green, Thomas A.

    2013-01-01

    Our prior research has shown that the transcription of endoplasmic reticulum (ER) stress transcription factors Activating Transcription Factor 3 (ATF3) and ATF4 are induced by amphetamine and restraint stress in rat striatum. However, presently it is unknown the full extent of ER stress responses to psychological stress or cocaine, and which of the three ER stress pathways is activated. The current study examines transcriptional responses of key ER stress target genes subsequent to psychologi...

  6. The quality control of glycoprotein folding in the endoplasmic reticulum, a trip from trypanosomes to mammals

    Directory of Open Access Journals (Sweden)

    A.J. Parodi

    1998-05-01

    Full Text Available The present review deals with the stages of synthesis and processing of asparagine-linked oligosaccharides occurring in the lumen of the endoplasmic reticulum and their relationship to the acquisition by glycoproteins of their proper tertiary structures. Special emphasis is placed on reactions taking place in trypanosomatid protozoa since their study has allowed the detection of the transient glucosylation of glycoproteins catalyzed by UDP-Glc:glycoprotein glucosyltransferase and glucosidase II. The former enzyme has the unique property of covalently tagging improperly folded conformations by catalyzing the formation of protein-linked Glc1Man7GlcNAc2, Glc1Man8GlcNac2 and Glc1Man9GlcNAc2 from the unglucosylated proteins. Glucosyltransferase is a soluble protein of the endoplasmic reticulum that recognizes protein domains exposed in denatured but not in native conformations (probably hydrophobic amino acids and the innermost N-acetylglucosamine unit that is hidden from macromolecular probes in most native glycoproteins. In vivo, the glucose units are removed by glucosidase II. The influence of oligosaccharides in glycoprotein folding is reviewed as well as the participation of endoplasmic reticulum chaperones (calnexin and calreticulin that recognize monoglucosylated species in the same process. A model for the quality control of glycoprotein folding in the endoplasmic reticulum, i.e., the mechanism by which cells recognize the tertiary structure of glycoproteins and only allow transit to the Golgi apparatus of properly folded species, is discussed. The main elements of this control are calnexin and calreticulin as retaining components, the UDP-Glc:glycoprotein glucosyltransferase as a sensor of tertiary structures and glucosidase II as the releasing agent.

  7. TBHQ Alleviated Endoplasmic Reticulum Stress-Apoptosis and Oxidative Stress by PERK-Nrf2 Crosstalk in Methamphetamine-Induced Chronic Pulmonary Toxicity

    Directory of Open Access Journals (Sweden)

    Yun Wang

    2017-01-01

    Full Text Available Methamphetamine (MA leads to cardiac and pulmonary toxicity expressed as increases in inflammatory responses and oxidative stress. However, some interactions may exist between oxidative stress and endoplasmic reticulum stress (ERS. The current study is designed to investigate if both oxidative stress and ERS are involved in MA-induced chronic pulmonary toxicity and if antioxidant tertiary butylhydroquinone (TBHQ alleviated ERS-apoptosis and oxidative stress by PERK-Nrf2 crosstalk. In this study, the rats were randomly divided into control group, MA-treated group (MA, and MA plus TBHQ-treated group (MA + TBHQ. Chronic exposure to MA resulted in slower growth of weight and pulmonary toxicity of the rats by increasing the pulmonary arterial pressure, promoting the hypertrophy of right ventricle and the remodeling of pulmonary arteries. MA inhibited the Nrf2-mediated antioxidative stress by downregulation of Nrf2, GCS, and HO-1 and upregulation of SOD2. MA increased GRP78 to induce ERS. Overexpression and phosphorylation of PERK rapidly phosphorylated eIF2α, increased ATF4, CHOP, bax, caspase 3, and caspase 12, and decreased bcl-2. These changes can be reversed by antioxidant TBHQ through upregulating expression of Nrf2. The above results indicated that TBHQ can alleviate MA-induced oxidative stress which can accelerate ERS to initiate PERK-dependent apoptosis and that PERK/Nrf2 is likely to be the key crosstalk between oxidative stress and ERS in MA-induced chronic pulmonary toxicity.

  8. Immunohistochemical evidence for expression of fast-twitch type sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA1) in German shepherd dogs with dilated cardiomyopathy myocardium.

    Science.gov (United States)

    Summerfield, Nuala; Peters, Mary E; Hercock, Carol A; Mobasheri, Ali; Young, Iain S

    2010-04-01

    Dilated cardiomyopathy (DCM) is one of the most common acquired canine heart diseases. It is particularly common in large and giant breed dogs. Although a great deal is known about the clinical progression and manifestations of the disease, the underlying cellular and molecular mechanisms remain poorly understood. One widely held belief is that calcium-handling abnormalities are critically involved in the disease process. This study investigates the changes in expression of the sarco(endo)plasmic reticulum calcium ATPase (SERCA) isoforms in DCM myocardium from German shepherd dogs. Affected tissue samples were obtained from German shepherd dogs with DCM, euthanized for intractable congestive heart failure while normal myocardial tissue samples were obtained from German shepherd dogs, euthanized for non-cardiovascular reasons. Tissue microarrays containing normal and DCM myocardium samples were prepared, immunostained with SERCA1 and SERCA2 antibodies and analyzed. We were able to demonstrate, for the first time, that while there is little change in the expression of the cardiac isoform (SERCA2), there is clear expression of the fast-twitch skeletal muscle isoform SERCA1 in the myocardium of dogs diagnosed with DCM. We propose that SERCA1 expression is evidence of a natural adaptive response to the impaired Ca2+ handling thought to occur in German shepherd dogs with DCM and heart failure. Copyright 2010 Elsevier B.V. All rights reserved.

  9. Endoplasmic reticulum stress in wake-active neurons progresses with aging.

    Science.gov (United States)

    Naidoo, Nirinjini; Zhu, Jingxu; Zhu, Yan; Fenik, Polina; Lian, Jie; Galante, Ray; Veasey, Sigrid

    2011-08-01

    Fragmentation of wakefulness and sleep are expected outcomes of advanced aging. We hypothesize that wake neurons develop endoplasmic reticulum dyshomeostasis with aging, in parallel with impaired wakefulness. In this series of experiments, we sought to more fully characterize age-related changes in wakefulness and then, in relevant wake neuronal populations, explore functionality and endoplasmic reticulum homeostasis. We report that old mice show greater sleep/wake transitions in the active period with markedly shortened wake periods, shortened latencies to sleep, and less wake time in the subjective day in response to a novel social encounter. Consistent with sleep/wake instability and reduced social encounter wakefulness, orexinergic and noradrenergic wake neurons in aged mice show reduced c-fos response to wakefulness and endoplasmic reticulum dyshomeostasis with increased nuclear translocation of CHOP and GADD34. We have identified an age-related unfolded protein response injury to and dysfunction of wake neurons. It is anticipated that these changes contribute to sleep/wake fragmentation and cognitive impairment in aging. © 2011 The Authors. Aging Cell © 2011 Blackwell Publishing Ltd/Anatomical Society of Great Britain and Ireland.

  10. Caspase-12 is involved in stretch-induced apoptosis mediated endoplasmic reticulum stress.

    Science.gov (United States)

    Zhang, Qiang; Liu, Jianing; Chen, Shulan; Liu, Jing; Liu, Lijuan; Liu, Guirong; Wang, Fang; Jiang, Wenxin; Zhang, Caixia; Wang, Shuangyu; Yuan, Xiao

    2016-04-01

    It is well recognized that mandibular growth, which is caused by a variety of functional appliances, is considered to be the result of both neuromuscular and skeletal adaptations. Accumulating evidence has demonstrated that apoptosis plays an important role in the adaptation of skeletal muscle function. However, the underlying mechanism of apoptosis that is induced by stretch continues to be incompletely understood. Endoplasmic reticulum stress (ERS), a newly defined signaling pathway, initiates apoptosis. This study seeks to determine if caspase-12 is involved in stretch-induced apoptosis mediated endoplasmic reticulum stress in myoblast and its underlying mechanism. Apoptosis was assessed by Hochest staining, DAPI staining and annexin V binding and PI staining. ER chaperones, such as GRP78, CHOP and caspase-12, were determined by reverse transcription polymerase chain reaction (RT-PCR) and Western blot. Furthermore, caspase-12 inhibitor was used to value the mechanism of the caspase-12 pathway. Apoptosis of myoblast, which is subjected to cyclic stretch, was observed in a time-dependent manner. We found that GRP78 mRNA and protein were significantly increased and CHOP and caspase-12 were activated in myoblast that was exposed to cyclic stretch. Caspase-12 inhibition reduced stretch-induced apoptosis, and caspase-12 activated caspase-3 to induce apoptosis. We concluded that caspase-12 played an important role in stretch-induced apoptosis that is associated by endoplasmic reticulum stress by activating caspase-3.

  11. Living cardiac patch: the elixir for cardiac regeneration.

    Science.gov (United States)

    Lakshmanan, Rajesh; Krishnan, Uma Maheswari; Sethuraman, Swaminathan

    2012-12-01

    A thorough understanding of the cellular and muscle fiber orientation in left ventricular cardiac tissue is of paramount importance for the generation of artificial cardiac patches to treat the ischemic myocardium. The major challenge faced during cardiac patch engineering is to choose a perfect combination of three entities; cells, scaffolds and signaling molecules comprising the tissue engineering triad for repair and regeneration. This review provides an overview of various scaffold materials, their mechanical properties and fabrication methods utilized in cardiac patch engineering. Stem cell therapies in clinical trials and the commercially available cardiac patch materials were summarized in an attempt to provide a recent perspective in the treatment of heart failure. Various tissue engineering strategies employed thus far to construct viable thick cardiac patches is schematically illustrated. Though many strategies have been proposed for fabrication of various cardiac scaffold materials, the stage and severity of the disease condition demands the incorporation of additional cues in a suitable scaffold material. The scaffold may be nanofibrous patch, hydrogel or custom designed films. Integration of stem cells and biomolecular cues along with the scaffold may provide the right microenvironment for the repair of unhealthy left ventricular tissue as well as promote its regeneration.

  12. The cardiac calsequestrin gene transcription is modulated at the promoter by NFAT and MEF-2 transcription factors.

    Directory of Open Access Journals (Sweden)

    Rafael Estrada-Avilés

    Full Text Available Calsequestrin-2 (CASQ2 is the main Ca2+-binding protein inside the sarcoplasmic reticulum of cardiomyocytes. Previously, we demonstrated that MEF-2 and SRF binding sites within the human CASQ2 gene (hCASQ2 promoter region are functional in neonatal cardiomyocytes. In this work, we investigated if the calcineurin/NFAT pathway regulates hCASQ2 expression in neonatal cardiomyocytes. The inhibition of NFAT dephosphorylation with CsA or INCA-6, reduced both the luciferase activity of hCASQ2 promoter constructs (-3102/+176 bp and -288/+176 bp and the CASQ2 mRNA levels in neonatal rat cardiomyocytes. Additionally, NFATc1 and NFATc3 over-expressing neonatal cardiomyocytes showed a 2-3-fold increase in luciferase activity of both hCASQ2 promoter constructs, which was prevented by CsA treatment. Site-directed mutagenesis of the -133 bp MEF-2 binding site prevented trans-activation of hCASQ2 promoter constructs induced by NFAT overexpression. Chromatin Immunoprecipitation (ChIP assays revealed NFAT and MEF-2 enrichment within the -288 bp to +76 bp of the hCASQ2 gene promoter. Besides, a direct interaction between NFAT and MEF-2 proteins was demonstrated by protein co-immunoprecipitation experiments. Taken together, these data demonstrate that NFAT interacts with MEF-2 bound to the -133 bp binding site at the hCASQ2 gene promoter. In conclusion, in this work, we demonstrate that the Ca2+-calcineurin/NFAT pathway modulates the transcription of the hCASQ2 gene in neonatal cardiomyocytes.

  13. Ca2+-regulated-cAMP/PKA signaling in cardiac pacemaker cells links ATP supply to demand.

    Science.gov (United States)

    Yaniv, Yael; Juhaszova, Magdalena; Lyashkov, Alexey E; Spurgeon, Harold A; Sollott, Steven J; Lakatta, Edward G

    2011-11-01

    In sinoatrial node cells (SANC), Ca(2+) activates adenylate cyclase (AC) to generate a high basal level of cAMP-mediated/protein kinase A (PKA)-dependent phosphorylation of Ca(2+) cycling proteins. These result in spontaneous sarcoplasmic-reticulum (SR) generated rhythmic Ca(2+) oscillations during diastolic depolarization, that not only trigger the surface membrane to generate rhythmic action potentials (APs), but, in a feed-forward manner, also activate AC/PKA signaling. ATP is consumed to pump Ca(2+) to the SR, to produce cAMP, to support contraction and to maintain cell ionic homeostasis. Since feedback mechanisms link ATP-demand to ATP production, we hypothesized that (1) both basal ATP supply and demand in SANC would be Ca(2+)-cAMP/PKA dependent; and (2) due to its feed-forward nature, a decrease in flux through the Ca(2+)-cAMP/PKA signaling axis will reduce the basal ATP production rate. O(2) consumption in spontaneous beating SANC was comparable to ventricular myocytes (VM) stimulated at 3 Hz. Graded reduction of basal Ca(2+)-cAMP/PKA signaling to reduce ATP demand in rabbit SANC produced graded ATP depletion (r(2)=0.96), and reduced O(2) consumption and flavoprotein fluorescence. Neither inhibition of glycolysis, selectively blocking contraction nor specific inhibition of mitochondrial Ca(2+) flux reduced the ATP level. Feed-forward basal Ca(2+)-cAMP/PKA signaling both consumes ATP to drive spontaneous APs in SANC and is tightly linked to mitochondrial ATP production. Interfering with Ca(2+)-cAMP/PKA signaling not only slows the firing rate and reduces ATP consumption, but also appears to reduce ATP production so that ATP levels fall. This distinctly differs from VM, which lack this feed-forward basal cAMP/PKA signaling, and in which ATP level remains constant when the demand changes. Published by Elsevier Ltd.

  14. Cardiac and vascular malformations

    International Nuclear Information System (INIS)

    Ley, S.; Ley-Zaporozhan, J.

    2015-01-01

    Malformations of the heart and great vessels show a high degree of variation. There are numerous variants and defects with only few clinical manifestations and are only detected by chance, such as a persistent left superior vena cava or a partial anomalous pulmonary venous connection. Other cardiovascular malformations are manifested directly after birth and need prompt mostly surgical interventions. At this point in time echocardiography is the diagnostic modality of choice for morphological and functional characterization of malformations. Additional imaging using computed tomography (CT) or magnetic resonance imaging (MRI) is only required in a minority of cases. If so, the small anatomical structures, the physiological tachycardia and tachypnea are a challenge for imaging modalities and strategies. This review article presents the most frequent vascular, cardiac and complex cardiovascular malformations independent of the first line diagnostic imaging modality. (orig.) [de

  15. Pneumothorax in cardiac pacing

    DEFF Research Database (Denmark)

    Kirkfeldt, Rikke Esberg; Johansen, Jens Brock; Nohr, Ellen Aagaard

    2012-01-01

    AIM: To identify risk factors for pneumothorax treated with a chest tube after cardiac pacing device implantation in a population-based cohort.METHODS AND RESULTS: A nationwide cohort study was performed based on data on 28 860 patients from the Danish Pacemaker Register, which included all Danish...... age was 77 years (25th and 75th percentile: 69-84) and 55% were male (n = 15 785). A total of 190 patients (0.66%) were treated for pneumothorax, which was more often in women [aOR 1.9 (1.4-2.6)], and in patients with age >80 years [aOR 1.4 (1.0-1.9)], a prior history of chronic obstructive pulmonary...

  16. Sudden Cardiac Death

    DEFF Research Database (Denmark)

    Risgaard, Bjarke; Winkel, Bo Gregers; Jabbari, Reza

    2017-01-01

    Objectives This study sought to describe the use of pharmacotherapy in a nationwide cohort of young patients with sudden cardiac death (SCD). Background Several drugs have been associated with an increased risk of SCD and sudden arrhythmic death syndrome (SADS). It remains unclear how...... pharmacotherapy may contribute to the overall burden of SCD in the general population. Methods This was a nationwide study that included all deaths that occurred between 2000 and 2009 and between 2007 and 2009 in people age 1 to 35 years and 36 to 49 years, respectively. Two physicians identified all SCDs through...... review of death certificates. Autopsy reports were collected. Pharmacotherapy prescribed within 90 days before SCD was identified in the Danish Registry of Medicinal Product Statistics. Results We identified 1,363 SCDs; median age was 38 years (interquartile range: 29 to 45 years), and 72% (n = 975) were men...

  17. Cardiac Rehabilitation Series: Canada

    Science.gov (United States)

    Grace, Sherry L.; Bennett, Stephanie; Ardern, Chris I.; Clark, Alexander

    2015-01-01

    Cardiovascular disease is among the leading causes of mortality and morbidity in Canada. Cardiac rehabilitation (CR) has a long robust history here, and there are established clinical practice guidelines. While the effectiveness of CR in the Canadian context is clear, only 34% of eligible patients participate, and strategies to increase access for under-represented groups (e.g., women, ethnic minority groups) are not yet universally applied. Identified CR barriers include lack of referral and physician recommendation, travel and distance, and low perceived need. Indeed there is now a national policy position recommending systematic inpatient referral to CR in Canada. Recent development of 30 CR Quality Indicators and the burgeoning national CR registry will enable further measurement and improvement of the quality of CR care in Canada. Finally, the Canadian Association of CR is one of the founding members of the International Council of Cardiovascular Prevention and Rehabilitation, to promote CR globally. PMID:24607018

  18. Cardiac potassium channel subtypes

    DEFF Research Database (Denmark)

    Schmitt, Nicole; Grunnet, Morten; Olesen, Søren-Peter

    2014-01-01

    About 10 distinct potassium channels in the heart are involved in shaping the action potential. Some of the K(+) channels are primarily responsible for early repolarization, whereas others drive late repolarization and still others are open throughout the cardiac cycle. Three main K(+) channels...... drive the late repolarization of the ventricle with some redundancy, and in atria this repolarization reserve is supplemented by the fairly atrial-specific KV1.5, Kir3, KCa, and K2P channels. The role of the latter two subtypes in atria is currently being clarified, and several findings indicate...... that they could constitute targets for new pharmacological treatment of atrial fibrillation. The interplay between the different K(+) channel subtypes in both atria and ventricle is dynamic, and a significant up- and downregulation occurs in disease states such as atrial fibrillation or heart failure...

  19. Hypertension and cardiac arrhythmias

    DEFF Research Database (Denmark)

    Lip, Gregory Y.H.; Coca, Antonio; Kahan, Thomas

    2017-01-01

    Hypertension is a common cardiovascular risk factor leading to heart failure (HF), coronary artery disease, stroke, peripheral artery disease and chronic renal insufficiency. Hypertensive heart disease can manifest as many cardiac arrhythmias, most commonly being atrial fibrillation (AF). Both...... supraventricular and ventricular arrhythmias may occur in hypertensive patients, especially in those with left ventricular hypertrophy (LVH) or HF. Also, some of the antihypertensive drugs commonly used to reduce blood pressure, such as thiazide diuretics, may result in electrolyte abnormalities (e.g. hypokalaemia......, hypomagnesemia), further contributing to arrhythmias, whereas effective control of blood pressure may prevent the development of the arrhythmias such as AF. In recognizing this close relationship between hypertension and arrhythmias, the European Heart Rhythm Association (EHRA) and the European Society...

  20. Mediastinitis after cardiac transplantation

    Directory of Open Access Journals (Sweden)

    Noedir A. G. Stolf

    2000-05-01

    Full Text Available OBJECTIVE: Assessment of incidence and behavior of mediastinitis after cardiac transplantation. METHODS: From 1985 to 1999, 214 cardiac transplantations were performed, 12 (5.6% of the transplanted patients developed confirmed mediastinitis. Patient's ages ranged from 42 to 66 years (mean of 52.3±10.0 years and 10 (83.3% patients were males. Seven (58.3% patients showed sternal stability on palpation, 4 (33.3% patients had pleural empyema, and 2 (16.7% patients did not show purulent secretion draining through the wound. RESULTS: Staphylococcus aureus was the infectious agent identified in the wound secretion or in the mediastinum, or both, in 8 (66.7% patients. Staphylococcus epidermidis was identified in 2 (16.7% patients, Enterococcus faecalis in 1 (8.3% patient, and the cause of mediastinitis could not be determined in 1 (8.3% patient. Surgical treatment was performed on an emergency basis, and the extension of the débridement varied with local conditions. In 2 (16.7% patients, we chose to leave the surgical wound open and performed daily dressings with granulated sugar. Total sternal resection was performed in only 1 (8.3% patient. Out of this series, 5 (41.7% patients died, and the causes of death were related to the infection. Autopsy revealed persistence of mediastinitis in 1 (8.3% patient. CONCLUSION: Promptness in diagnosing mediastinitis and precocious surgical drainage have changed the natural evolution of this disease. Nevertheless, observance of the basic precepts of prophylaxis of infection is still the best way to treat mediastinitis.

  1. Cardiac function in acute hypothyroidism

    International Nuclear Information System (INIS)

    Donaghue, K.; Hales, I.; Allwright, S.; Cooper, R.; Edwards, A.; Grant, S.; Morrow, A.; Wilmshurst, E.; Royal North Shore Hospital, Sydney

    1985-01-01

    It has been established that chronic hypothyroidism may affect cardiac function by several mechanisms. It is not known how long the patient has to be hypothyroid for cardiac involvement to develop. This study was undertaken to assess the effect of a short period of hypothyroidism (10 days) on cardiac function. Nine patients who had had total tyroidectomy, had received ablative radioiodine for thyroid cancer and were euthyroid on replacement therapy were studied while both euthyroid and hypothyroid. Cardiac assessment was performed by X-ray, ECG, echocardiography and gated blood-pool scans. After 10 days of hypothyroidisms, the left-ventricular ejection fraction failed to rise after exercise in 4 of the 9 patients studied, which was significant (P<0.002). No significant changes in cardiac size or function at rest were detected. This functional abnormality in the absence of any demonstrable change in cardiac size and the absence of pericardial effussion with normal basal function suggest that short periods of hypothyroidism may reduce cardiac reserve, mostly because of alterations in metabolic function. (orig.)

  2. Trends in Cardiac Pacemaker Batteries

    Directory of Open Access Journals (Sweden)

    Venkateswara Sarma Mallela

    2004-10-01

    Full Text Available Batteries used in Implantable cardiac pacemakers-present unique challenges to their developers and manufacturers in terms of high levels of safety and reliability. In addition, the batteries must have longevity to avoid frequent replacements. Technological advances in leads/electrodes have reduced energy requirements by two orders of magnitude. Micro-electronics advances sharply reduce internal current drain concurrently decreasing size and increasing functionality, reliability, and longevity. It is reported that about 600,000 pacemakers are implanted each year worldwide and the total number of people with various types of implanted pacemaker has already crossed 3 million. A cardiac pacemaker uses half of its battery power for cardiac stimulation and the other half for housekeeping tasks such as monitoring and data logging. The first implanted cardiac pacemaker used nickel-cadmium rechargeable battery, later on zinc-mercury battery was developed and used which lasted for over 2 years. Lithium iodine battery invented and used by Wilson Greatbatch and his team in 1972 made the real impact to implantable cardiac pacemakers. This battery lasts for about 10 years and even today is the power source for many manufacturers of cardiac pacemakers. This paper briefly reviews various developments of battery technologies since the inception of cardiac pacemaker and presents the alternative to lithium iodine battery for the near future.

  3. Protective Effects of Olive Leaf Extract on Acrolein-Exacerbated Myocardial Infarction via an Endoplasmic Reticulum Stress Pathway

    Directory of Open Access Journals (Sweden)

    Yuyu Xu

    2018-02-01

    Full Text Available Many studies reported that air pollution particulate matter (PM exposure was associated with myocardial infarction (MI. Acrolein representing the unsaturated aldehydes, the main component of PM, derives from the incomplete combustion of wood, plastic, fossil fuels and the main constitute of cigarette smoking. However, the effect of acrolein on MI remains not that clear. In the current study, the effect of acrolein-exacerbated MI was investigated. In vivo, male Sprague–Dawley rats received olive leaf extract (OLE followed by acrolein, then isoprenaline (ISO was received by subcutaneous injection to induce MI. Results showed that the expression levels of GRP78 and CHOP, two major components of endoplasmic reticulum (ER stress were higher in the combination of acrolein and ISO than those in ISO treatment. The apoptosis marker, Bax, was also higher while the anti-apoptosis indicator, Bcl2 expression was lower both at protein and mRNA levels in the combination group. Also, the acrolein-protein adducts and myocardial pathological damage increased in the combination of acrolein and ISO relative to the ISO treatment. Besides, cardiac parameters, ejection fraction (EF and fractional shortening (FS were reduced more significantly when acrolein was added than in ISO treatment. Interestingly, all the changes were able to be ameliorated by OLE. Since hydroxytyrosol (HT and oleuropein (OP were the main components in OLE, we next investigated the effect of HT and OP on cardiomyocyte H9c2 cell apoptosis induced by acrolein through ER stress and Bax pathway. Results showed that GRP78, CHOP and Bax expression were upregulated, while Bcl2 expression was downregulated both at the protein and mRNA levels, when the H9c2 cells were treated with acrolein. In addition, pretreatment with HT can reverse the expression of GRP78, CHOP, Bax and Bcl2 on the protein and mRNA levels, while there was no effect of OP on the expression of GRP78 and CHOP on the mRNA levels

  4. Metoclopramide-induced cardiac arrest

    Directory of Open Access Journals (Sweden)

    Martha M. Rumore

    2011-11-01

    Full Text Available The authors report a case of cardiac arrest in a patient receiving intravenous (IV metoclopramide and review the pertinent literature. A 62-year-old morbidly obese female admitted for a gastric sleeve procedure, developed cardiac arrest within one minute of receiving metoclopramide 10 mg via slow intravenous (IV injection. Bradycardia at 4 beats/min immediately appeared, progressing rapidly to asystole. Chest compressions restored vital function. Electrocardiogram (ECG revealed ST depression indicative of myocardial injury. Following intubation, the patient was transferred to the intensive care unit. Various cardiac dysrrhythmias including supraventricular tachycardia (SVT associated with hypertension and atrial fibrillation occurred. Following IV esmolol and metoprolol, the patient reverted to normal sinus rhythm. Repeat ECGs revealed ST depression resolution without pre-admission changes. Metoclopramide is a non-specific dopamine receptor antagonist. Seven cases of cardiac arrest and one of sinus arrest with metoclopramide were found in the literature. The metoclopramide prescribing information does not list precautions or adverse drug reactions (ADRs related to cardiac arrest. The reaction is not dose related but may relate to the IV administration route. Coronary artery disease was the sole risk factor identified. According to Naranjo, the association was possible. Other reports of cardiac arrest, severe bradycardia, and SVT were reviewed. In one case, five separate IV doses of 10 mg metoclopramide were immediately followed by asystole repeatedly. The mechanism(s underlying metoclopramide’s cardiac arrest-inducing effects is unknown. Structural similarities to procainamide may play a role. In view of eight previous cases of cardiac arrest from metoclopramide having been reported, further elucidation of this ADR and patient monitoring is needed. Our report should alert clinicians to monitor patients and remain diligent in surveillance and

  5. Cardiac cone-beam CT

    International Nuclear Information System (INIS)

    Manzke, Robert

    2005-01-01

    This doctoral thesis addresses imaging of the heart with retrospectively gated helical cone-beam computed tomography (CT). A thorough review of the CT reconstruction literature is presented in combination with a historic overview of cardiac CT imaging and a brief introduction to other cardiac imaging modalities. The thesis includes a comprehensive chapter about the theory of CT reconstruction, familiarizing the reader with the problem of cone-beam reconstruction. The anatomic and dynamic properties of the heart are outlined and techniques to derive the gating information are reviewed. With the extended cardiac reconstruction (ECR) framework, a new approach is presented for the heart-rate-adaptive gated helical cardiac cone-beam CT reconstruction. Reconstruction assessment criteria such as the temporal resolution, the homogeneity in terms of the cardiac phase, and the smoothness at cycle-to-cycle transitions are developed. Several reconstruction optimization approaches are described: An approach for the heart-rate-adaptive optimization of the temporal resolution is presented. Streak artifacts at cycle-to-cycle transitions can be minimized by using an improved cardiac weighting scheme. The optimal quiescent cardiac phase for the reconstruction can be determined automatically with the motion map technique. Results for all optimization procedures applied to ECR are presented and discussed based on patient and phantom data. The ECR algorithm is analyzed for larger detector arrays of future cone-beam systems throughout an extensive simulation study based on a four-dimensional cardiac CT phantom. The results of the scientific work are summarized and an outlook proposing future directions is given. The presented thesis is available for public download at www.cardiac-ct.net

  6. Acupuncture therapy related cardiac injury.

    Science.gov (United States)

    Li, Xue-feng; Wang, Xian

    2013-12-01

    Cardiac injury is the most serious adverse event in acupuncture therapy. The causes include needling chest points near the heart, the cardiac enlargement and pericardial effusion that will enlarge the projected area on the body surface and make the proper depth of needling shorter, and the incorrect needling method of the points. Therefore, acupuncture practitioners must be familiar with the points of the heart projected area on the chest and the correct needling methods in order to reduce the risk of acupuncture therapy related cardiac injury.

  7. The Johannesburg cardiac rehabilitation programme

    African Journals Online (AJOL)

    1991-02-16

    Feb 16, 1991 ... sion 72,9% of patients were smokers, 26,3% had hypertension and 34,3% had ... Cardiac rehabilitation, including supervised exercise therapy, has become a .... sions on risk factor modification, diet, aspects of heart disease,.

  8. Recent developments in cardiac pacing.

    Science.gov (United States)

    Rodak, D J

    1995-10-01

    Indications for cardiac pacing continue to expand. Pacing to improve functional capacity, which is now common, relies on careful patient selection and technical improvements, such as complex software algorithms and diagnostic capabilities.

  9. Robotic Applications in Cardiac Surgery

    Directory of Open Access Journals (Sweden)

    Alan P. Kypson

    2008-11-01

    Full Text Available Traditionally, cardiac surgery has been performed through a median sternotomy, which allows the surgeon generous access to the heart and surrounding great vessels. As a paradigm shift in the size and location of incisions occurs in cardiac surgery, new methods have been developed to allow the surgeon the same amount of dexterity and accessibility to the heart in confined spaces and in a less invasive manner. Initially, long instruments without pivot points were used, however, more recent robotic telemanipulation systems have been applied that allow for improved dexterity, enabling the surgeon to perform cardiac surgery from a distance not previously possible. In this rapidly evolving field, we review the recent history and clinical results of using robotics in cardiac surgery.

  10. Optimal Technique in Cardiac Anesthesia Recovery

    OpenAIRE

    Svircevic, V.

    2014-01-01

    The aim of this thesis is to evaluate fast-track cardiac anesthesia techniques and investigate their impact on postoperative mortality, morbidity and quality of life. The following topics will be discussed in the thesis. (1.) Is fast track cardiac anesthesia a safe technique for cardiac surgery? (2.) Does thoracic epidural anesthesia have an effect on mortality and morbidity after cardiac surgery? (3.) Does thoracic epidural anesthesia have an effect on quality of life after cardiac surgery? ...

  11. The sarcolipin-bound calcium pump stabilizes calcium sites exposed to the cytoplasm

    DEFF Research Database (Denmark)

    Winther, Anne-Marie Lund; Bublitz, Maike; Karlsen, Jesper Lykkegaard

    2013-01-01

    The contraction and relaxation of muscle cells is controlled by the successive rise and fall of cytosolic Ca(2+), initiated by the release of Ca(2+) from the sarcoplasmic reticulum and terminated by re-sequestration of Ca(2+) into the sarcoplasmic reticulum as the main mechanism of Ca(2+) removal...

  12. Muscle Glycogen Content Modifies SR Ca2 + Release Rate in Elite Endurance Athletes

    DEFF Research Database (Denmark)

    Gejl, Kasper Degn; Hvid, Lars G; Frandsen, Ulrik

    2014-01-01

    The aim of the present study was to investigate the influence of muscle glycogen content on sarcoplasmic reticulum (SR) function and peak power output (Wpeak) in elite endurance athletes.......The aim of the present study was to investigate the influence of muscle glycogen content on sarcoplasmic reticulum (SR) function and peak power output (Wpeak) in elite endurance athletes....

  13. Cardiac effects of noncardiac neoplasms

    International Nuclear Information System (INIS)

    Schoen, F.J.; Berger, B.M.; Guerina, N.G.

    1984-01-01

    Clinically significant cardiovascular abnormalities may occur as secondary manifestations of noncardiac neoplasms. The principal cardiac effects of noncardiac tumors include the direct results of metastases to the heart or lungs, the indirect effects of circulating tumor products (causing nonbacterial thrombotic endocarditis, myeloma-associated amyloidosis, pheochromocytoma-associated cardiac hypertrophy and myofibrillar degeneration, and carcinoid heart disease), and the undesired cardiotoxicities of chemotherapy and radiotherapy. 89 references

  14. Imaging in cardiac mass lesions

    International Nuclear Information System (INIS)

    Mundinger, A.; Gruber, H.P.; Dinkel, E.; Geibel, A.; Beck, A.; Wimmer, B.; Schlosser, V.

    1992-01-01

    In 26 patients with cardiac mass lesions confirmed by surgery, diagnostic imaging was performed preoperatively by means of two-dimensional echocardiography (26 patients), angiography (12 patients), correlative computed tomography (CT, 8 patients), and magnetic resonance imaging (MRI, 3 patients). Two-dimensional echocardiography correctly identified the cardiac masses in all patients. Angiography missed two of 12 cardiac masses; CT missed one of eight. MRI identified three of three cardiac masses. Although the sensitivity of two-dimensional echocardiography was high (100%), all methods lacked specificity. None of the methods allowed differentiation between myxoma (n=13) and thrombus (n=7). Malignancy of the lesions was successfully predicted by noninvasive imaging methods in all six patients. However, CT and MRI provided additional information concerning cardiac mural infiltration, pericardial involvement, and extracardiac tumor extension, and should be integrated within a preoperative imaging strategy. Thus two-dimensional echocardiography is the method of choice for primary assessment of patients with suspected cardiac masses. Further preoperative imaging by CT or MRI can be limited to patients with malignancies suspected on the grounds of pericardial effusion or other clinical results. (author)

  15. Cardiac imaging. A multimodality approach

    Energy Technology Data Exchange (ETDEWEB)

    Thelen, Manfred [Johannes Gutenberg University Hospital, Mainz (Germany); Erbel, Raimund [University Hospital Essen (Germany). Dept. of Cardiology; Kreitner, Karl-Friedrich [Johannes Gutenberg University Hospital, Mainz (Germany). Clinic and Polyclinic for Diagnostic and Interventional Radiology; Barkhausen, Joerg (eds.) [University Hospital Schleswig-Holstein, Luebeck (Germany). Dept. of Radiology and Nuclear Medicine

    2009-07-01

    An excellent atlas on modern diagnostic imaging of the heart Written by an interdisciplinary team of experts, Cardiac Imaging: A Multimodality Approach features an in-depth introduction to all current imaging modalities for the diagnostic assessment of the heart as well as a clinical overview of cardiac diseases and main indications for cardiac imaging. With a particular emphasis on CT and MRI, the first part of the atlas also covers conventional radiography, echocardiography, angiography and nuclear medicine imaging. Leading specialists demonstrate the latest advances in the field, and compare the strengths and weaknesses of each modality. The book's second part features clinical chapters on heart defects, endocarditis, coronary heart disease, cardiomyopathies, myocarditis, cardiac tumors, pericardial diseases, pulmonary vascular diseases, and diseases of the thoracic aorta. The authors address anatomy, pathophysiology, and clinical features, and evaluate the various diagnostic options. Key features: - Highly regarded experts in cardiology and radiology off er image-based teaching of the latest techniques - Readers learn how to decide which modality to use for which indication - Visually highlighted tables and essential points allow for easy navigation through the text - More than 600 outstanding images show up-to-date technology and current imaging protocols Cardiac Imaging: A Multimodality Approach is a must-have desk reference for cardiologists and radiologists in practice, as well as a study guide for residents in both fields. It will also appeal to cardiac surgeons, general practitioners, and medical physicists with a special interest in imaging of the heart. (orig.)

  16. Cardiac imaging. A multimodality approach

    International Nuclear Information System (INIS)

    Thelen, Manfred; Erbel, Raimund; Kreitner, Karl-Friedrich; Barkhausen, Joerg

    2009-01-01

    An excellent atlas on modern diagnostic imaging of the heart Written by an interdisciplinary team of experts, Cardiac Imaging: A Multimodality Approach features an in-depth introduction to all current imaging modalities for the diagnostic assessment of the heart as well as a clinical overview of cardiac diseases and main indications for cardiac imaging. With a particular emphasis on CT and MRI, the first part of the atlas also covers conventional radiography, echocardiography, angiography and nuclear medicine imaging. Leading specialists demonstrate the latest advances in the field, and compare the strengths and weaknesses of each modality. The book's second part features clinical chapters on heart defects, endocarditis, coronary heart disease, cardiomyopathies, myocarditis, cardiac tumors, pericardial diseases, pulmonary vascular diseases, and diseases of the thoracic aorta. The authors address anatomy, pathophysiology, and clinical features, and evaluate the various diagnostic options. Key features: - Highly regarded experts in cardiology and radiology off er image-based teaching of the latest techniques - Readers learn how to decide which modality to use for which indication - Visually highlighted tables and essential points allow for easy navigation through the text - More than 600 outstanding images show up-to-date technology and current imaging protocols Cardiac Imaging: A Multimodality Approach is a must-have desk reference for cardiologists and radiologists in practice, as well as a study guide for residents in both fields. It will also appeal to cardiac surgeons, general practitioners, and medical physicists with a special interest in imaging of the heart. (orig.)

  17. Urotensin II promotes vagal-mediated bradycardia by activating cardiac-projecting parasympathetic neurons of nucleus ambiguus.

    Science.gov (United States)

    Brailoiu, Gabriela Cristina; Deliu, Elena; Rabinowitz, Joseph E; Tilley, Douglas G; Koch, Walter J; Brailoiu, Eugen

    2014-05-01

    Urotensin II (U-II) is a cyclic undecapeptide that regulates cardiovascular function at central and peripheral sites. The functional role of U-II nucleus ambiguus, a key site controlling cardiac tone, has not been established, despite the identification of U-II and its receptor at this level. We report here that U-II produces an increase in cytosolic Ca(2+) concentration in retrogradely labeled cardiac vagal neurons of nucleus ambiguus via two pathways: (i) Ca(2+) release from the endoplasmic reticulum via inositol 1,4,5-trisphosphate receptor; and (ii) Ca(2+) influx through P/Q-type Ca(2+) channels. In addition, U-II depolarizes cultured cardiac parasympathetic neurons. Microinjection of increasing concentrations of U-II into nucleus ambiguus elicits dose-dependent bradycardia in conscious rats, indicating the in vivo activation of the cholinergic pathway controlling the heart rate. Both the in vitro and in vivo effects were abolished by the urotensin receptor antagonist, urantide. Our findings suggest that, in addition, to the previously reported increase in sympathetic outflow, U-II activates cardiac vagal neurons of nucleus ambiguus, which may contribute to cardioprotection. © 2014 International Society for Neurochemistry.

  18. Cardiac output during exercise

    DEFF Research Database (Denmark)

    Siebenmann, C; Rasmussen, P.; Sørensen, H.

    2015-01-01

    Several techniques assessing cardiac output (Q) during exercise are available. The extent to which the measurements obtained from each respective technique compares to one another, however, is unclear. We quantified Q simultaneously using four methods: the Fick method with blood obtained from...... the right atrium (Q(Fick-M)), Innocor (inert gas rebreathing; Q(Inn)), Physioflow (impedance cardiography; Q(Phys)), and Nexfin (pulse contour analysis; Q(Pulse)) in 12 male subjects during incremental cycling exercise to exhaustion in normoxia and hypoxia (FiO2  = 12%). While all four methods reported...... a progressive increase in Q with exercise intensity, the slopes of the Q/oxygen uptake (VO2) relationship differed by up to 50% between methods in both normoxia [4.9 ± 0.3, 3.9 ± 0.2, 6.0 ± 0.4, 4.8 ± 0.2 L/min per L/min (mean ± SE) for Q(Fick-M), Q(Inn), QP hys and Q(Pulse), respectively; P = 0...

  19. Recurrent late cardiac tamponade following cardiac surgery : a deceiving and potentially lethal complication

    NARCIS (Netherlands)

    Harskamp, Ralf E.; Meuzelaar, Jacobus J.

    2010-01-01

    Background - Cardiac tamponade, characterized by inflow obstruction of the heart chambers by extracardiac compression, is a potentially lethal complication following cardiac surgery. Case report - We present a case of recurrent cardiac tamponade following valve surgery. At first presentation,

  20. Recurrent late cardiac tamponade following cardiac surgery: a deceiving and potentially lethal complication

    NARCIS (Netherlands)

    Harskamp, Ralf E.; Meuzelaar, Jacobus J.

    2010-01-01

    Cardiac tamponade, characterized by inflow obstruction of the heart chambers by extracardiac compression, is a potentially lethal complication following cardiac surgery. We present a case of recurrent cardiac tamponade following valve surgery. At first presentation, diagnosis was delayed because of

  1. Cardiac function and cognition in older community-dwelling cardiac patients

    NARCIS (Netherlands)

    Eggermont, Laura H.P.; Aly, Mohamed F.A.; Vuijk, Pieter J.; de Boer, Karin; Kamp, Otto; van Rossum, Albert C.; Scherder, Erik J.A.

    2017-01-01

    Background: Cognitive deficits have been reported in older cardiac patients. An underlying mechanism for these findings may be reduced cardiac function. The relationship between cardiac function as represented by different echocardiographic measures and different cognitive function domains in older

  2. The involvement of SMILE/TMTC3 in endoplasmic reticulum stress response.

    Directory of Open Access Journals (Sweden)

    Maud Racapé

    Full Text Available The state of operational tolerance has been detected sporadically in some renal transplanted patients that stopped immunosuppressive drugs, demonstrating that allograft tolerance might exist in humans. Several years ago, a study by Brouard et al. identified a molecular signature of several genes that were significantly differentially expressed in the blood of such patients compared with patients with other clinical situations. The aim of the present study is to analyze the role of one of these molecules over-expressed in the blood of operationally tolerant patients, SMILE or TMTC3, a protein whose function is still unknown.We first confirmed that SMILE mRNA is differentially expressed in the blood of operationally tolerant patients with drug-free long term graft function compared to stable and rejecting patients. Using a yeast two-hybrid approach and a colocalization study by confocal microscopy we furthermore report an interaction of SMILE with PDIA3, a molecule resident in the endoplasmic reticulum (ER. In accordance with this observation, SMILE silencing in HeLa cells correlated with the modulation of several transcripts involved in proteolysis and a decrease in proteasome activity. Finally, SMILE silencing increased HeLa cell sensitivity to the proteasome inhibitor Bortezomib, a drug that induces ER stress via protein overload, and increased transcript expression of a stress response protein, XBP-1, in HeLa cells and keratinocytes.In this study we showed that SMILE is involved in the endoplasmic reticulum stress response, by modulating proteasome activity and XBP-1 transcript expression. This function of SMILE may influence immune cell behavior in the context of transplantation, and the analysis of endoplasmic reticulum stress in transplantation may reveal new pathways of regulation in long-term graft acceptance thereby increasing our understanding of tolerance.

  3. Respiratory metabolism and calorie restriction relieve persistent endoplasmic reticulum stress induced by calcium shortage in yeast

    DEFF Research Database (Denmark)

    Busti, Stefano; Mapelli, Valeria; Tripodi, Farida

    2016-01-01

    respiration. Calcium homeostasis, protein biosynthesis and the unfolded protein response are tightly intertwined and the consequences of facing calcium starvation are determined by whether cellular energy production is balanced with demands for anabolic functions. Our findings confirm that the connections...... reticulum (ER stress) triggers the unfolded protein response (UPR) and generates a state of oxidative stress that decreases cell viability. These effects are severe during growth on rapidly fermentable carbon sources and can be mitigated by decreasing the protein synthesis rate or by inducing cellular...

  4. A postmortem study on indigestible foreign bodies in the rumen and reticulum of ruminants, eastern Ethiopia

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    Seifu Negash

    2015-05-01

    Full Text Available A cross-sectional study was conducted on ruminants (cattle, sheep and goats slaughtered at Haramaya University and Haramaya municipal abattoirs from November 2013 to April 2014 in Haramaya, eastern Ethiopia. The objective of the study was to identify types and estimate the prevalence of foreign bodies in the rumen and reticulum of domestic ruminants in the area. From 810 randomly selected study animals, 422 (52.1% were found to have foreign bodies. Of the 332 cattle, 193 sheep and 285 goats examined, 144 (43.4%, 109 (56.5% and 169 (59.3% respectively were found with various types of foreign bodies. The prevalence of foreign bodies was significantly (χ2 = 17.53, p < 0.05 higher in sheep (59.3% and goats (56.7% than in cattle (43.4%. Overall the prevalence of foreign bodies in study animals with poor body condition was significantly higher (χ2 = 38.57, p < 0.05 than in those with medium and good body condition. A higher percentage of foreign bodies occurred in the rumen alone (87.9% than in the reticulum alone (5.0%, with the rest present in both. Significantly higher proportions of foreign bodies were observed in the rumen of cattle (χ2 = 332, p < 0.05, sheep (χ2 = 193, p < 0.05 and goats (χ2 = 285.0, p = 0.000 than in the reticulum. Plastic was the most commonly encountered (79.2% foreign body, followed by cloth (15.3% and rope (12.3%. In addition, metal (0.9% and calcified material and/or stone (1.0% were found in the reticulum of cattle. Lack of a plastic waste disposal system in the area as well as communal/free grazing of livestock in highly waste-polluted areas seemed to be major factors in the high occurrence of foreign bodies in ruminants. To change this, collaborative intervention schemes involving professionals, policy makers, livestock keepers and environmental activists are needed.

  5. Bacteria, the endoplasmic reticulum and the unfolded protein response: friends or foes?

    Science.gov (United States)

    Celli, Jean; Tsolis, Renée M

    2015-02-01

    The unfolded protein response (UPR) is a cytoprotective response that is aimed at restoring cellular homeostasis following physiological stress exerted on the endoplasmic reticulum (ER), which also invokes innate immune signalling in response to invading microorganisms. Although it has been known for some time that the UPR is modulated by various viruses, recent evidence indicates that it also has multiple roles during bacterial infections. In this Review, we describe how bacteria interact with the ER, including how bacteria induce the UPR, how subversion of the UPR promotes bacterial proliferation and how the UPR contributes to innate immune responses against invading bacteria.

  6. The metabolomic signature of Leber's hereditary optic neuropathy reveals endoplasmic reticulum stress.

    Science.gov (United States)

    Chao de la Barca, Juan Manuel; Simard, Gilles; Amati-Bonneau, Patrizia; Safiedeen, Zainab; Prunier-Mirebeau, Delphine; Chupin, Stéphanie; Gadras, Cédric; Tessier, Lydie; Gueguen, Naïg; Chevrollier, Arnaud; Desquiret-Dumas, Valérie; Ferré, Marc; Bris, Céline; Kouassi Nzoughet, Judith; Bocca, Cinzia; Leruez, Stéphanie; Verny, Christophe; Miléa, Dan; Bonneau, Dominique; Lenaers, Guy; Martinez, M Carmen; Procaccio, Vincent; Reynier, Pascal

    2016-11-01

    Leber's hereditary optic neuropathy (MIM#535000), the commonest mitochondrial DNA-related disease, is caused by mutations affecting mitochondrial complex I. The clinical expression of the disorder, usually occurring in young adults, is typically characterized by subacute, usually sequential, bilateral visual loss, resulting from the degeneration of retinal ganglion cells. As the precise action of mitochondrial DNA mutations on the overall cell metabolism in Leber's hereditary optic neuropathy is unknown, we investigated the metabolomic profile of the disease. High performance liquid chromatography coupled with tandem mass spectrometry was used to quantify 188 metabolites in fibroblasts from 16 patients with Leber's hereditary optic neuropathy and eight healthy control subjects. Latent variable-based statistical methods were used to identify discriminating metabolites. One hundred and twenty-four of the metabolites were considered to be accurately quantified. A supervised orthogonal partial least squares discriminant analysis model separating patients with Leber's hereditary optic neuropathy from control subjects showed good predictive capability (Q 2cumulated = 0.57). Thirty-eight metabolites appeared to be the most significant variables, defining a Leber's hereditary optic neuropathy metabolic signature that revealed decreased concentrations of all proteinogenic amino acids, spermidine, putrescine, isovaleryl-carnitine, propionyl-carnitine and five sphingomyelin species, together with increased concentrations of 10 phosphatidylcholine species. This signature was not reproduced by the inhibition of complex I with rotenone or piericidin A in control fibroblasts. The importance of sphingomyelins and phosphatidylcholines in the Leber's hereditary optic neuropathy signature, together with the decreased amino acid pool, suggested an involvement of the endoplasmic reticulum. This was confirmed by the significantly increased phosphorylation of PERK and eIF2α, as well as

  7. Clofibric Acid Increases the Formation of Oleic Acid in Endoplasmic Reticulum of the Liver of Rats

    OpenAIRE

    広瀬, 明彦; 山崎, 研; 坂本, 武史; 須永, 克佳; 津田, 整; 光本, 篤史; 工藤, なをみ; 川嶋, 洋一

    2011-01-01

    The effects of 2-(4-chlorophenoxy)-2-methylpropionic acid (clofibric acid) on the formation of oleic acid (18:1) from stearic acid (18:0) and utilization of the 18:1 formed for phosphatidylcholine (PC) formation in endoplasmic reticulum in the liver of rats were studied in vivo. [14C]18:0 was intravenously injected into control Wistar male rats and rats that had been fed on a diet containing 0.5% (w/w) clofibric acid for 7 days; and the distribution of radiolabeled fatty acids among subcellul...

  8. Processing and turnover of the Hedgehog protein in the endoplasmic reticulum

    OpenAIRE

    Chen, Xin; Tukachinsky, Hanna; Huang, Chih-Hsiang; Jao, Cindy; Chu, Yue-Ru; Tang, Hsiang-Yun; Mueller, Britta; Schulman, Sol; Rapoport, Tom A.; Salic, Adrian

    2011-01-01

    The Hedgehog (Hh) signaling pathway has important functions during metazoan development. The Hh ligand is generated from a precursor by self-cleavage, which requires a free cysteine in the C-terminal part of the protein and results in the production of the cholesterol-modified ligand and a C-terminal fragment. In this paper, we demonstrate that these reactions occur in the endoplasmic reticulum (ER). The catalytic cysteine needs to form a disulfide bridge with a conserved cysteine, which is s...

  9. The endoplasmic reticulum exerts control over organelle streaming during cell expansion.

    Science.gov (United States)

    Stefano, Giovanni; Renna, Luciana; Brandizzi, Federica

    2014-03-01

    Cytoplasmic streaming is crucial for cell homeostasis and expansion but the precise driving forces are largely unknown. In plants, partial loss of cytoplasmic streaming due to chemical and genetic ablation of myosins supports the existence of yet-unknown motors for organelle movement. Here we tested a role of the endoplasmic reticulum (ER) as propelling force for cytoplasmic streaming during cell expansion. Through quantitative live-cell analyses in wild-type Arabidopsis thaliana cells and mutants with compromised ER structure and streaming, we demonstrate that cytoplasmic streaming undergoes profound changes during cell expansion and that it depends on motor forces co-exerted by the ER and the cytoskeleton.

  10. Halogenated anaesthetics and cardiac protection in cardiac and non-cardiac anaesthesia

    Directory of Open Access Journals (Sweden)

    Landoni Giovanni

    2009-01-01

    Full Text Available Volatile anaesthetic agents have direct protective properties against ischemic myocardial damage. The implementation of these properties during clinical anaesthesia can provide an additional tool in the treatment or prevention, or both, of ischemic cardiac dysfunction in the perioperative period. A recent meta-analysis showed that desflurane and sevoflurane reduce postoperative mortality and incidence of myocardial infarction following cardiac surgery, with significant advantages in terms of postoperative cardiac troponin release, need for inotrope support, time on mechanical ventilation, intensive care unit and overall hospital stay. Multicentre, randomised clinical trials had previously demonstrated that the use of desflurane can reduce the postoperative release of cardiac troponin I, the need for inotropic support, and the number of patients requiring prolonged hospitalisation following coronary artery bypass graft surgery either with and without cardiopulmonary bypass. The American College of Cardiology/American Heart Association Guidelines recommend volatile anaesthetic agents during non-cardiac surgery for the maintenance of general anaesthesia in patients at risk for myocardial infarction. Nonetheless, e vidence in non-coronary surgical settings is contradictory and will be reviewed in this paper together with the mechanisms of cardiac protection by volatile agents.

  11. Ca(2+ release events in cardiac myocytes up close: insights from fast confocal imaging.

    Directory of Open Access Journals (Sweden)

    Vyacheslav M Shkryl

    Full Text Available The spatio-temporal properties of Ca(2+ transients during excitation-contraction coupling and elementary Ca(2+ release events (Ca(2+ sparks were studied in atrial and ventricular myocytes with ultra-fast confocal microscopy using a Zeiss LSM 5 LIVE system that allows sampling rates of up to 60 kHz. Ca(2+ sparks which originated from subsarcolemmal junctional sarcoplasmic reticulum (j-SR release sites in atrial myocytes were anisotropic and elongated in the longitudinal direction of the cell. Ca(2+ sparks in atrial cells originating from non-junctional SR and in ventricular myocytes were symmetrical. Ca(2+ spark recording in line scan mode at 40,000 lines/s uncovered step-like increases of [Ca(2+]i. 2-D imaging of Ca(2+ transients revealed an asynchronous activation of release sites and allowed the sequential recording of Ca(2+ entry through surface membrane Ca(2+ channels and subsequent activation of Ca(2+-induced Ca(2+ release. With a latency of 2.5 ms after application of an electrical stimulus, Ca(2+ entry could be detected that was followed by SR Ca(2+ release after an additional 3 ms delay. Maximum Ca(2+ release was observed 4 ms after the beginning of release. The timing of Ca(2+ entry and release was confirmed by simultaneous [Ca(2+]i and membrane current measurements using the whole cell voltage-clamp technique. In atrial cells activation of discrete individual release sites of the j-SR led to spatially restricted Ca(2+ release events that fused into a peripheral ring of elevated [Ca(2+]i that subsequently propagated in a wave-like fashion towards the center of the cell. In ventricular myocytes asynchronous Ca(2+ release signals from discrete sites with no preferential subcellular location preceded the whole-cell Ca(2+ transient. In summary, ultra-fast confocal imaging allows investigation of Ca(2+ signals with a time resolution similar to patch clamp technique, however in a less invasive fashion.

  12. Cardiac rehabilitation costs.

    Science.gov (United States)

    Moghei, Mahshid; Turk-Adawi, Karam; Isaranuwatchai, Wanrudee; Sarrafzadegan, Nizal; Oh, Paul; Chessex, Caroline; Grace, Sherry L

    2017-10-01

    Despite the clinical benefits of cardiac rehabilitation (CR) and its cost-effectiveness, it is not widely received. Arguably, capacity could be greatly increased if lower-cost models were implemented. The aims of this review were to describe: the costs associated with CR delivery, approaches to reduce these costs, and associated implications. Upon finalizing the PICO statement, information scientists were enlisted to develop the search strategy of MEDLINE, Embase, CDSR, Google Scholar and Scopus. Citations identified were considered for inclusion by the first author. Extracted cost data were summarized in tabular format and qualitatively synthesized. There is wide variability in the cost of CR delivery around the world, and patients pay out-of-pocket for some or all of services in 55% of countries. Supervised CR costs in high-income countries ranged from PPP$294 (Purchasing Power Parity; 2016 United States Dollars) in the United Kingdom to PPP$12,409 in Italy, and in middle-income countries ranged from PPP$146 in Venezuela to PPP$1095 in Brazil. Costs relate to facilities, personnel, and session dose. Delivering CR using information and communication technology (mean cost PPP$753/patient/program), lowering the dose and using lower-cost personnel and equipment are important strategies to consider in containing costs, however few explicitly low-cost models are available in the literature. More research is needed regarding the costs to deliver CR in community settings, the cost-effectiveness of CR in most countries, and the economic impact of return-to-work with CR participation. A low-cost model of CR should be standardized and tested for efficacy across multiple healthcare systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Patch in Cardiac Surgery

    Directory of Open Access Journals (Sweden)

    Alireza Alizadeh Ghavidel

    2014-06-01

    Full Text Available Introduction: Excessive bleeding presents a risk for the patient in cardiovascular surgery. Local haemostatic agents are of great value to reduce bleeding and related complications. TachoSil (Nycomed, Linz, Austria is a sterile, haemostatic agent that consists of an equine collagen patchcoated with human fibrinogen and thrombin. This study evaluated the safety and efficacy of TachoSil compared to conventional technique.Methods: Forty-two patients scheduled for open heart surgeries, were entered to this study from August 2010 to May 2011. After primary haemostatic measures, patients divided in two groups based on surgeon’s judgment. Group A: 20 patients for whom TachoSil was applied and group B: 22 patients that conventional method using Surgicel (13 patients or wait and see method (9 cases, were performed in order to control the bleeding. In group A, 10 patients were male with mean age of 56.95±15.67 years and in group B, 9 cases were male with mean age of 49.95±14.41 years. In case group 70% (14/20 of the surgeries were redo surgeries versus 100% (22/22 in control group.Results: Baseline characteristics were similar in both groups. In TachoSil group 75% of patients required transfusion versus 90.90% in group B (P=0.03.Most transfusions consisted of packed red blood cell; 2±1.13 units in group A versus 3.11±1.44 in group B (P=0.01, however there were no significant differences between two groups regarding the mean total volume of intra and post-operative bleeding. Re-exploration was required in 10% in group A versus 13.63% in group B (P=0.67.Conclusion: TachoSil may act as a superior alternative in different types of cardiac surgery in order to control the bleeding and therefore reducing transfusion requirement.

  14. The orphan nuclear receptor NR4A1 (Nur77) regulates oxidative and endoplasmic reticulum stress in pancreatic cancer cells.

    Science.gov (United States)

    Lee, Syng-Ook; Jin, Un-Ho; Kang, Jeong Han; Kim, Sang Bae; Guthrie, Aaron S; Sreevalsan, Sandeep; Lee, Ju-Seog; Safe, Stephen

    2014-04-01

    NR4A1 (Nur77, TR3) is an orphan nuclear receptor that is overexpressed in pancreatic cancer and exhibits pro-oncogenic activity. RNA interference of NR4A1 expression in Panc-1 cells induced apoptosis and subsequent proteomic analysis revealed the induction of several markers of endoplasmic reticulum stress, including glucose-related protein 78 (GRP78), CCAAT/enhancer-binding protein-homologous protein (CHOP), and activating transcription factor-4 (ATF-4). Treatment of pancreatic cancer cells with the NR4A1 antagonist 1,1-bis(3'-indolyl)-1-(p-hydroxyphenyl)methane (DIM-C-pPhOH) gave similar results. Moreover, both NR4A1 knockdown and DIM-C-pPhOH induced reactive oxygen species (ROS), and induction of ROS and endoplasmic reticulum stress by these agents was attenuated after cotreatment with antioxidants. Manipulation of NR4A1 expression coupled with gene expression profiling identified a number of ROS metabolism transcripts regulated by NR4A1. Knockdown of one of these transcripts, thioredoxin domain containing 5 (TXNDC5), recapitulated the elevated ROS and endoplasmic reticulum stress; thus, demonstrating that NR4A1 regulates levels of endoplasmic reticulum stress and ROS in pancreatic cancer cells to facilitate cell proliferation and survival. Finally, inactivation of NR4A1 by knockdown or DIM-C-pPhOH decreased TXNDC5, resulting in activation of the ROS/endoplasmic reticulum stress and proapoptotic pathways. The NR4A1 receptor is pro-oncogenic, regulates the ROS/endoplasmic reticulum stress pathways, and inactivation of the receptor represents a novel pathway for inducing cell death in pancreatic cancer. Mol Cancer Res; 12(4); 527-38. ©2014 AACR.

  15. Animal models of cardiac cachexia.

    Science.gov (United States)

    Molinari, Francesca; Malara, Natalia; Mollace, Vincenzo; Rosano, Giuseppe; Ferraro, Elisabetta

    2016-09-15

    Cachexia is the loss of body weight associated with several chronic diseases including chronic heart failure (CHF). The cachectic condition is mainly due to loss of skeletal muscle mass and adipose tissue depletion. The majority of experimental in vivo studies on cachexia rely on animal models of cancer cachexia while a reliable and appropriate model for cardiac cachexia has not yet been established. A critical issue in generating a cardiac cachexia model is that genetic modifications or pharmacological treatments impairing the heart functionality and used to obtain the heart failure model might likely impair the skeletal muscle, this also being a striated muscle and sharing with the myocardium several molecular and physiological mechanisms. On the other hand, often, the induction of heart damage in the several existing models of heart failure does not necessarily lead to skeletal muscle loss and cachexia. Here we describe the main features of cardiac cachexia and illustrate some animal models proposed for cardiac cachexia studies; they include the genetic calsequestrin and Dahl salt-sensitive models, the monocrotaline model and the surgical models obtained by left anterior descending (LAD) ligation, transverse aortic constriction (TAC) and ascending aortic banding. The availability of a specific animal model for cardiac cachexia is a crucial issue since, besides the common aspects of cachexia in the different syndromes, each disease has some peculiarities in its etiology and pathophysiology leading to cachexia. Such peculiarities need to be unraveled in order to find new targets for effective therapies. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  16. Cytoskeletal-assisted dynamics of the mitochondrial reticulum in living cells.

    Science.gov (United States)

    Knowles, Michelle K; Guenza, Marina G; Capaldi, Roderick A; Marcus, Andrew H

    2002-11-12

    Subcellular organelle dynamics are strongly influenced by interactions with cytoskeletal filaments and their associated motor proteins, and lead to complex multiexponential relaxations that occur over a wide range of spatial and temporal scales. Here we report spatio-temporal measurements of the fluctuations of the mitochondrial reticulum in osteosarcoma cells by using Fourier imaging correlation spectroscopy, over time and distance scales of 10(-2) to 10(3) s and 0.5-2.5 microm. We show that the method allows a more complete description of mitochondrial dynamics, through the time- and length-scale-dependent collective diffusion coefficient D(k,tau), than available by other means. Addition of either nocodazole to disrupt microtubules or cytochalasin D to disassemble microfilaments simplifies the intermediate scattering function. When both drugs are used, the reticulum morphology of mitochondria is retained even though the cytoskeletal elements have been de-polymerized. The dynamics of the organelle are then primarily diffusive and can be modeled as a collection of friction points interconnected by elastic springs. This study quantitatively characterizes organelle dynamics in terms of collective cytoskeletal interactions in living cells.

  17. Endoplasmic reticulum calcium transport ATPase expression during differentiation of colon cancer and leukaemia cells

    International Nuclear Information System (INIS)

    Papp, Bela; Brouland, Jean-Philippe; Gelebart, Pascal; Kovacs, Tuende; Chomienne, Christine

    2004-01-01

    The calcium homeostasis of the endoplasmic reticulum (ER) is connected to a multitude of cell functions involved in intracellular signal transduction, control of proliferation, programmed cell death, or the synthesis of mature proteins. Calcium is accumulated in the ER by various biochemically distinct sarco/endoplasmic reticulum calcium transport ATPase isoenzymes (SERCA isoforms). Experimental data indicate that the SERCA composition of some carcinoma and leukaemia cell types undergoes significant changes during differentiation, and that this is accompanied by modifications of SERCA-dependent calcium accumulation in the ER. Because ER calcium homeostasis can also influence cell differentiation, we propose that the modulation of the expression of various SERCA isoforms, and in particular, the induction of the expression of SERCA3-type proteins, is an integral part of the differentiation program of some cancer and leukaemia cell types. The SERCA content of the ER may constitute a new parameter by which the calcium homeostatic characteristics of the organelle are adjusted. The cross-talk between ER calcium homeostasis and cell differentiation may have some implications for the better understanding of the signalling defects involved in the acquisition and maintenance of the malignant phenotype

  18. Mitochondrial enzymes and endoplasmic reticulum calcium stores as targets of oxidative stress in neurodegenerative diseases.

    Science.gov (United States)

    Gibson, Gary E; Huang, Hsueh-Meei

    2004-08-01

    Considerable evidence indicates that oxidative stress accompanies age-related neurodegenerative diseases. Specific mechanisms by which oxidative stress leads to neurodegeneration are unknown. Two targets of oxidative stress that are known to change in neurodegenerative diseases are the mitochondrial enzyme alpha-ketoglutarate dehydrogenase complex (KGDHC) and endoplasmic reticulum calcium stores. KGDHC activities are diminished in all common neurodegenerative diseases and the changes are particularly well documented in Alzheimer's disease (AD). A second change that occurs in cells from AD patients is an exaggerated endoplasmic reticulum calcium store [i.e., bombesin-releasable calcium stores (BRCS)]. H(2)O(2), a general oxidant, changes both variables in the same direction as occurs in disease. Other oxidants selectively alter these variables. Various antioxidants were used to help define the critical oxidant species that modifies these responses. All of the antioxidants diminish the oxidant-induced carboxy-dichlorofluorescein (cDCF) detectable reactive oxygen species (ROS), but have diverse actions on these cellular processes. For example, alpha-keto-beta-methyl-n-valeric acid (KMV) diminishes the H(2)O(2) effects on BRCS, while trolox and DMSO exaggerate the response. Acute trolox treatment does not alter H(2)O(2)-induced changes in KGDHC, whereas chronic treatment with trolox increases KGDHC almost threefold. The results suggest that KGDHC and BRCS provide targets by which oxidative stress may induce neurodegeneration and a useful tool for selecting antioxidants for reversing age-related neurodegeneration.

  19. Roles of Endoplasmic Reticulum Stress in NECA-Induced Cardioprotection against Ischemia/Reperfusion Injury

    Directory of Open Access Journals (Sweden)

    Fengmei Xing

    2017-01-01

    Full Text Available Objective. This study aimed to investigate whether the nonselective A2 adenosine receptor agonist NECA induces cardioprotection against myocardial ischemia/reperfusion (I/R injury via glycogen synthase kinase 3β (GSK-3β and the mitochondrial permeability transition pore (mPTP through inhibition of endoplasmic reticulum stress (ERS. Methods and Results. H9c2 cells were exposed to H2O2 for 20 minutes. NECA significantly prevented H2O2-induced TMRE fluorescence reduction, indicating that NECA inhibited the mPTP opening. NECA blocked H2O2-induced GSK-3β phosphorylation and GRP94 expression. NECA increased GSK-3β phosphorylation and decreased GRP94 expression, which were prevented by both ERS inductor 2-DG and PKG inhibitor KT5823, suggesting that NECA may induce cardioprotection through GSK-3β and cGMP/PKG via ERS. In isolated rat hearts, both NECA and the ERS inhibitor TUDCA decreased myocardial infarction, increased GSK-3β phosphorylation, and reversed GRP94 expression at reperfusion, suggesting that NECA protected the heart by inhibiting GSK-3β and ERS. Transmission electron microscopy showed that NECA and TUDCA reduced mitochondrial swelling and endoplasmic reticulum expansion, further supporting that NECA protected the heart by preventing the mPTP opening and ERS. Conclusion. These data suggest that NECA prevents the mPTP opening through inactivation of GSK-3β via ERS inhibition. The cGMP/PKG signaling pathway is responsible for GSK-3β inactivation by NECA.

  20. Involvement of Endoplasmic Reticulum Stress in Capsaicin-Induced Apoptosis of Human Pancreatic Cancer Cells

    Directory of Open Access Journals (Sweden)

    Shengzhang Lin

    2013-01-01

    Full Text Available Capsaicin, main pungent ingredient of hot chilli peppers, has been shown to have anticarcinogenic effect on various cancer cells through multiple mechanisms. In this study, we investigated the apoptotic effect of capsaicin on human pancreatic cancer cells in both in vitro and in vivo systems, as well as the possible mechanisms involved. In vitro, treatment of both the pancreatic cancer cells (PANC-1 and SW1990 with capsaicin resulted in cells growth inhibition, G0/G1 phase arrest, and apoptosis in a dose-dependent manner. Knockdown of growth arrest- and DNA damage-inducible gene 153 (GADD153, a marker of the endoplasmic-reticulum-stress- (ERS- mediated apoptosis pathway, by specific siRNA attenuated capsaicin-induced apoptosis both in PANC-1 and SW1990 cells. Moreover, in vivo studies capsaicin effectively inhibited the growth and metabolism of pancreatic cancer and prolonged the survival time of pancreatic cancer xenograft tumor-induced mice. Furthermore, capsaicin increased the expression of some key ERS markers, including glucose-regulated protein 78 (GRP78, phosphoprotein kinase-like endoplasmic reticulum kinase (phosphoPERK, and phosphoeukaryotic initiation factor-2α (phospho-eIF2α, activating transcription factor 4 (ATF4 and GADD153 in tumor tissues. In conclusion, we for the first time provide important evidence to support the involvement of ERS in the induction of apoptosis in pancreatic cancer cells by capsaicin.

  1. p53-inducible DHRS3 Is an Endoplasmic Reticulum Protein Associated with Lipid Droplet Accumulation*

    Science.gov (United States)

    Deisenroth, Chad; Itahana, Yoko; Tollini, Laura; Jin, Aiwen; Zhang, Yanping

    2011-01-01

    The transcription factor p53 plays a critical role in maintaining homeostasis as it relates to cellular growth, proliferation, and metabolism. In an effort to identify novel p53 target genes, a microarray approach was utilized to identify DHRS3 (also known as retSDR1) as a robust candidate gene. DHRS3 is a highly conserved member of the short chain alcohol dehydrogenase/reductase superfamily with a reported role in lipid and retinoid metabolism. Here, we demonstrate that DHRS3 is an endoplasmic reticulum (ER) protein that is shuttled to the ER via an N-terminal endoplasmic reticulum targeting signal. One important function of the ER is synthesis of neutral lipids that are packaged into lipid droplets whose biogenesis occurs from ER-derived membranes. DHRS3 is enriched at focal points of lipid droplet budding where it also localizes to the phospholipid monolayer of ER-derived lipid droplets. p53 promotes lipid droplet accumulation in a manner consistent with DHRS3 enrichment in the ER. As a p53 target gene, the observations of Dhrs3 location and potential function provide novel insight into an unexpected role for p53 in lipid droplet dynamics with implications in cancer cell metabolism and obesity. PMID:21659514

  2. Tannic Acid Induces Endoplasmic Reticulum Stress-Mediated Apoptosis in Prostate Cancer.

    Science.gov (United States)

    Nagesh, Prashanth K B; Hatami, Elham; Chowdhury, Pallabita; Kashyap, Vivek K; Khan, Sheema; Hafeez, Bilal B; Chauhan, Subhash C; Jaggi, Meena; Yallapu, Murali M

    2018-03-07

    Endoplasmic reticulum (ER) stress is an intriguing target with significant clinical importance in chemotherapy. Interference with ER functions can lead to the accumulation of unfolded proteins, as detected by transmembrane sensors that instigate the unfolded protein response (UPR). Therefore, controlling induced UPR via ER stress with natural compounds could be a novel therapeutic strategy for the management of prostate cancer. Tannic acid (a naturally occurring polyphenol) was used to examine the ER stress mediated UPR pathway in prostate cancer cells. Tannic acid treatment inhibited the growth, clonogenic, invasive, and migratory potential of prostate cancer cells. Tannic acid demonstrated activation of ER stress response (Protein kinase R-like endoplasmic reticulum kinase (PERK) and inositol requiring enzyme 1 (IRE1)) and altered its regulatory proteins (ATF4, Bip, and PDI) expression. Tannic acid treatment affirmed upregulation of apoptosis-associated markers (Bak, Bim, cleaved caspase 3, and cleaved PARP), while downregulation of pro-survival proteins (Bcl-2 and Bcl-xL). Tannic acid exhibited elevated G₁ population, due to increase in p18 INK4C and p21 WAF1/CIP1 expression, while cyclin D1 expression was inhibited. Reduction of MMP2 and MMP9, and reinstated E-cadherin signifies the anti-metastatic potential of this compound. Altogether, these results demonstrate that tannic acid can promote apoptosis via the ER stress mediated UPR pathway, indicating a potential candidate for cancer treatment.

  3. On The gamma-ray emission from Reticulum II and other dwarf galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Hooper, Dan; Linden, Tim

    2015-09-01

    The recent discovery of ten new dwarf galaxy candidates by the Dark Energy Survey (DES) and the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) could increase the Fermi Gamma-Ray Space Telescope's sensitivity to annihilating dark matter particles, potentially enabling a definitive test of the dark matter interpretation of the long-standing Galactic Center gamma-ray excess. In this paper, we compare the previous analyses of Fermi data from the directions of the new dwarf candidates (including the relatively nearby Reticulum II) and perform our own analysis, with the goal of establishing the statistical significance of any gamma-ray signal from these sources. We confirm the presence of an excess from Reticulum II, with a spectral shape that is compatible with the Galactic Center signal. The significance of this emission is greater than that observed from 99.84% of randomly chosen high-latitude blank-sky locations, corresponding to a local detection significance of 3.2σ. We caution that any dark matter interpretation of this excess must be validated through observations of additional dwarf spheroidal galaxies, and improved calculations of the relative J-factor of dwarf spheroidal galaxies. We improve upon the standard blank-sky calibration approach through the use of multi-wavelength catalogs, which allow us to avoid regions that are likely to contain unresolved gamma-ray sources.

  4. The Endoplasmic Reticulum Coat Protein II Transport Machinery Coordinates Cellular Lipid Secretion and Cholesterol Biosynthesis*

    Science.gov (United States)

    Fryer, Lee G. D.; Jones, Bethan; Duncan, Emma J.; Hutchison, Claire E.; Ozkan, Tozen; Williams, Paul A.; Alder, Olivia; Nieuwdorp, Max; Townley, Anna K.; Mensenkamp, Arjen R.; Stephens, David J.; Dallinga-Thie, Geesje M.; Shoulders, Carol C.

    2014-01-01

    Triglycerides and cholesterol are essential for life in most organisms. Triglycerides serve as the principal energy storage depot and, where vascular systems exist, as a means of energy transport. Cholesterol is essential for the functional integrity of all cellular membrane systems. The endoplasmic reticulum is the site of secretory lipoprotein production and de novo cholesterol synthesis, yet little is known about how these activities are coordinated with each other or with the activity of the COPII machinery, which transports endoplasmic reticulum cargo to the Golgi. The Sar1B component of this machinery is mutated in chylomicron retention disorder, indicating that this Sar1 isoform secures delivery of dietary lipids into the circulation. However, it is not known why some patients with chylomicron retention disorder develop hepatic steatosis, despite impaired intestinal fat malabsorption, and why very severe hypocholesterolemia develops in this condition. Here, we show that Sar1B also promotes hepatic apolipoprotein (apo) B lipoprotein secretion and that this promoting activity is coordinated with the processes regulating apoB expression and the transfer of triglycerides/cholesterol moieties onto this large lipid transport protein. We also show that although Sar1A antagonizes the lipoprotein secretion-promoting activity of Sar1B, both isoforms modulate the expression of genes encoding cholesterol biosynthetic enzymes and the synthesis of cholesterol de novo. These results not only establish that Sar1B promotes the secretion of hepatic lipids but also adds regulation of cholesterol synthesis to Sar1B's repertoire of transport functions. PMID:24338480

  5. Crystallization and preliminary X-ray diffraction analysis of human endoplasmic reticulum aminopeptidase 2

    International Nuclear Information System (INIS)

    Ascher, David B.; Polekhina, Galina; Parker, Michael W.

    2012-01-01

    The luminal domain of human endoplasmic reticulum aminopeptidase 2 has been expressed, purified and crystallized. The crystals belonged to the orthorhombic space group P2 1 2 1 2 and diffracted anisotropically to 3.3 Å resolution in the best direction on an in-house source. Endoplasmic reticulum aminopeptidase 2 (ERAP2) is a critical enzyme involved in the final processing of MHC class I antigens. Peptide trimming by ERAP2 and the other members of the oxytocinase subfamily is essential to customize longer precursor peptides in order to fit them to the correct length required for presentation on major histocompatibility complex class I molecules. While recent structures of ERAP1 have provided an understanding of the ‘molecular-ruler’ mechanism of substrate selection, little is known about the complementary activities of its homologue ERAP2 despite their sharing 49% sequence identity. In order to gain insights into the structure–function relationship of the oxytocinase subfamily, and in particular ERAP2, the luminal region of human ERAP2 has been crystallized in the presence of the inhibitor bestatin. The crystals belonged to an orthorhombic space group and diffracted anisotropically to 3.3 Å resolution in the best direction on an in-house X-ray source. A molecular-replacement solution suggested that the enzyme has adopted the closed state as has been observed in other inhibitor-bound aminopeptidase structures

  6. Blocking variant surface glycoprotein synthesis alters endoplasmic reticulum exit sites/Golgi homeostasis in Trypanosoma brucei.

    Science.gov (United States)

    Ooi, Cher-Pheng; Smith, Terry K; Gluenz, Eva; Wand, Nadina Vasileva; Vaughan, Sue; Rudenko, Gloria

    2018-06-01

    The predominant secretory cargo of bloodstream form Trypanosoma brucei is variant surface glycoprotein (VSG), comprising ~10% total protein and forming a dense protective layer. Blocking VSG translation using Morpholino oligonucleotides triggered a precise pre-cytokinesis arrest. We investigated the effect of blocking VSG synthesis on the secretory pathway. The number of Golgi decreased, particularly in post-mitotic cells, from 3.5 ± 0.6 to 2.0 ± 0.04 per cell. Similarly, the number of endoplasmic reticulum exit sites (ERES) in post-mitotic cells dropped from 3.9 ± 0.6 to 2.7 ± 0.1 eight hours after blocking VSG synthesis. The secretory pathway was still functional in these stalled cells, as monitored using Cathepsin L. Rates of phospholipid and glycosylphosphatidylinositol-anchor biosynthesis remained relatively unaffected, except for the level of sphingomyelin which increased. However, both endoplasmic reticulum and Golgi morphology became distorted, with the Golgi cisternae becoming significantly dilated, particularly at the trans-face. Membrane accumulation in these structures is possibly caused by reduced budding of nascent vesicles due to the drastic reduction in the total amount of secretory cargo, that is, VSG. These data argue that the total flux of secretory cargo impacts upon the biogenesis and maintenance of secretory structures and organelles in T. brucei, including the ERES and Golgi. © 2018 The Authors. Traffic published by John Wiley & Sons Ltd.

  7. Methods for monitoring endoplasmic reticulum stress and the unfolded protein response.

    LENUS (Irish Health Repository)

    Samali, Afshin

    2010-01-01

    The endoplasmic reticulum (ER) is the site of folding of membrane and secreted proteins in the cell. Physiological or pathological processes that disturb protein folding in the endoplasmic reticulum cause ER stress and activate a set of signaling pathways termed the Unfolded Protein Response (UPR). The UPR can promote cellular repair and sustained survival by reducing the load of unfolded proteins through upregulation of chaperones and global attenuation of protein synthesis. Research into ER stress and the UPR continues to grow at a rapid rate as many new investigators are entering the field. There are also many researchers not working directly on ER stress, but who wish to determine whether this response is activated in the system they are studying: thus, it is important to list a standard set of criteria for monitoring UPR in different model systems. Here, we discuss approaches that can be used by researchers to plan and interpret experiments aimed at evaluating whether the UPR and related processes are activated. We would like to emphasize that no individual assay is guaranteed to be the most appropriate one in every situation and strongly recommend the use of multiple assays to verify UPR activation.

  8. Computed tomography of the abdomen in Saanen goats: I.Reticulum, rumen and omasum

    International Nuclear Information System (INIS)

    Braun, U.; Irmer, M.; Augsburger, H.; Jud, R.; Ohlert, S.

    2011-01-01

    Computed tomography (CT) of the reticulum, rumen and omasum was carried out in 30 healthy goats and the images were compared to corresponding body sections obtained at postmortem. A multidetector CT was used to examine goats in sternal recumbency. A setting of 120 KV and 270 mA was used to produce 1.5-mm transverse slices from the fifth thoracic vertebra to the sacrum. Soft tissue structures were assessed in a soft tissue with a window width (W) of 400 Hounsfield Units (HU), and a window level (L) of 40 HU. The layering of the ruminal contents was assessed in an ingesta window with a W of 1500 HU and an L of 30 HU. After subjective evaluation, the size of the rumen and omasum, the thickness of the walls of the reticulum, rumen and omasum and the height of the gas cap and fibre and liquid phases of the rumen were measured. Fifteen goats were euthanised after CT examination, placed in sternal recumbency and frozen at -18 єC for three to 10 days. Thirteen goats were then cut into 1.0- to 1.5-cm-thick transverse slices. One goat was cut in dorsal-plane slices and another in sagittal slices. The structures in the CT images were identified by using the corresponding anatomical slices

  9. Methods for Monitoring Endoplasmic Reticulum Stress and the Unfolded Protein Response

    Directory of Open Access Journals (Sweden)

    Afshin Samali

    2010-01-01

    Full Text Available The endoplasmic reticulum (ER is the site of folding of membrane and secreted proteins in the cell. Physiological or pathological processes that disturb protein folding in the endoplasmic reticulum cause ER stress and activate a set of signaling pathways termed the Unfolded Protein Response (UPR. The UPR can promote cellular repair and sustained survival by reducing the load of unfolded proteins through upregulation of chaperones and global attenuation of protein synthesis. Research into ER stress and the UPR continues to grow at a rapid rate as many new investigators are entering the field. There are also many researchers not working directly on ER stress, but who wish to determine whether this response is activated in the system they are studying: thus, it is important to list a standard set of criteria for monitoring UPR in different model systems. Here, we discuss approaches that can be used by researchers to plan and interpret experiments aimed at evaluating whether the UPR and related processes are activated. We would like to emphasize that no individual assay is guaranteed to be the most appropriate one in every situation and strongly recommend the use of multiple assays to verify UPR activation.

  10. Impact of high cholesterol and endoplasmic reticulum stress on metabolic diseases: An updated mini-review

    Directory of Open Access Journals (Sweden)

    Erdi Sozen

    2017-08-01

    Full Text Available Endoplasmic reticulum (ER is the major site of protein folding and calcium storage. Beside the role of ER in protein homeostasis, it controls the cholesterol production and lipid-membrane biosynthesis as well as surviving and cell death signaling mechanisms in the cell. It is well-documented that elevated plasma cholesterol induces adverse effects in cardiovascular diseases (CVDs, liver disorders, such as non-alcoholic fatty liver disease (NAFLD, non-alcoholic steatosis hepatitis (NASH, and metabolic diseases which are associated with oxidative and ER stress. Recent animal model and human studies have showed high cholesterol and ER stress as an emerging factors involved in the development of many metabolic diseases. In this review, we will summarize the crucial effects of hypercholesterolemia and ER stress response in the pathogenesis of CVDs, NAFLD/NASH, diabetes and obesity which are major health problems in western countries. Keywords: Endoplasmic reticulum stress, High cholesterol, Cardiovascular diseases, Non-alcoholic fatty liver disease, Non-alcoholic steatosis hepatitis

  11. Hypothyroidism Causes Endoplasmic Reticulum Stress in Adult Rat Hippocampus: A Mechanism Associated with Hippocampal Damage

    Directory of Open Access Journals (Sweden)

    Alejandra Paola Torres-Manzo

    2018-01-01

    Full Text Available Thyroid hormones (TH are essential for hippocampal neuronal viability in adulthood, and their deficiency causes hypothyroidism, which is related to oxidative stress events and neuronal damage. Also, it has been hypothesized that hypothyroidism causes a glucose deprivation in the neuron. This study is aimed at evaluating the temporal participation of the endoplasmic reticulum stress (ERE in hippocampal neurons of adult hypothyroid rats and its association with the oxidative stress events. Adult Wistar male rats were divided into euthyroid and hypothyroid groups. Thyroidectomy with parathyroid gland reimplementation caused hypothyroidism at three weeks postsurgery. Oxidative stress, redox environment, and antioxidant enzyme markers, as well as the expression of the ERE through the pathways of PERK, ATF6, and IRE1, were evaluated at the 3rd and 4th weeks postsurgery. We found a rise in ROS and nitrite production; also, catalase increased and glutathione peroxidase diminished their activities. These events promote an enhancement of the lipoperoxidation, as well as of γ-GT, myeloperoxidase, and caspase 3 activities. With respect to ERE, there were ATF6, IRE1, and GADD153 overexpressions with a reduction in mitochondrial activity and GSH2/GSSG ratio. We conclude that the endoplasmic reticulum stress might play a pivotal role in the activation of hypothyroidism-induced hippocampal cell death.

  12. Endoplasmic Reticulum Stress-Mediated Hippocampal Neuron Apoptosis Involved in Diabetic Cognitive Impairment

    Directory of Open Access Journals (Sweden)

    Xiaoming Zhang

    2013-01-01

    Full Text Available Poor management of DM causes cognitive impairment while the mechanism is still unconfirmed. The aim of the present study was to investigate the activation of C/EBP Homology Protein (CHOP, the prominent mediator of the endoplasmic reticulum (ER stress-induced apoptosis under hyperglycemia. We employed streptozotocin- (STZ- induced diabetic rats to explore the ability of learning and memory by the Morris water maze test. The ultrastructure of hippocampus in diabetic rats and cultured neurons in high glucose medium were observed by transmission electron microscopy and scanning electron microscopy. TUNEL staining was also performed to assess apoptotic cells while the expression of CHOP was assayed by immunohistochemistry and Western blot assay in these hippocampal neurons. Six weeks after diabetes induction, the escape latency increased and the average frequency in finding the platform decreased in diabetic rats (P<0.05. The morphology of neuron and synaptic structure was impaired; the number of TUNEL-positive cells and the expression of CHOP in hippocampus of diabetic rats and high glucose medium cultured neurons were markedly altered (P<0.05. The present results suggested that the CHOP-dependent endoplasmic reticulum (ER stress-mediated apoptosis may be involved in hyperglycemia-induced hippocampal synapses and neurons impairment and promote the diabetic cognitive impairment.

  13. Perioperative Rosuvastatin in Cardiac Surgery.

    Science.gov (United States)

    Zheng, Zhe; Jayaram, Raja; Jiang, Lixin; Emberson, Jonathan; Zhao, Yan; Li, Qi; Du, Juan; Guarguagli, Silvia; Hill, Michael; Chen, Zhengming; Collins, Rory; Casadei, Barbara

    2016-05-05

    Complications after cardiac surgery are common and lead to substantial increases in morbidity and mortality. Meta-analyses of small randomized trials have suggested that perioperative statin therapy can prevent some of these complications. We randomly assigned 1922 patients in sinus rhythm who were scheduled for elective cardiac surgery to receive perioperative rosuvastatin (at a dose of 20 mg daily) or placebo. The primary outcomes were postoperative atrial fibrillation within 5 days after surgery, as assessed by Holter electrocardiographic monitoring, and myocardial injury within 120 hours after surgery, as assessed by serial measurements of the cardiac troponin I concentration. Secondary outcomes included major in-hospital adverse events, duration of stay in the hospital and intensive care unit, left ventricular and renal function, and blood biomarkers. The concentrations of low-density lipoprotein cholesterol and C-reactive protein after surgery were lower in patients assigned to rosuvastatin than in those assigned to placebo (PSTICS ClinicalTrials.gov number, NCT01573143.).

  14. Comparing Methods for Cardiac Output

    DEFF Research Database (Denmark)

    Graeser, Karin; Zemtsovski, Mikhail; Kofoed, Klaus F

    2018-01-01

    of the left ventricular outflow tract. METHODS: The primary aim was a systematic comparison of CO with Doppler-derived 3D TEE and CO by thermodilution in a broad population of patients undergoing cardiac surgery. A subanalysis was performed comparing cross-sectional area by TEE with cardiac computed...... tomography (CT) angiography. Sixty-two patients, scheduled for elective heart surgery, were included; 1 was subsequently excluded for logistic reasons. Inclusion criteria were coronary artery bypass surgery (N = 42) and aortic valve replacement (N = 19). Exclusion criteria were chronic atrial fibrillation......, left ventricular ejection fraction below 0.40 and intracardiac shunts. Nineteen randomly selected patients had a cardiac CT the day before surgery. All images were stored for blinded post hoc analyses, and Bland-Altman plots were used to assess agreement between measurement methods, defined as the bias...

  15. Cerebral Oximetry in Cardiac Surgery

    Directory of Open Access Journals (Sweden)

    A. N. Shepelyuk

    2012-01-01

    Full Text Available Based on the data of numerous current references, the review describes different neuromonitoring methods during cardiac surgery under extracorporeal circulation. It shows that it is important and necessary to make neuromonitoring for the early diagnosis and prevention of neurological complications after cardiac surgery. Particular attention is given to cerebral oximetry; the possibilities and advantages of this technique are described. Correction of cerebral oximetric values is shown to improve survival rates and to reduce the incidence of postoperative complications. Lack of cerebral oximetry monitoring denudes a clinician of important information and possibilities to optimize patient status and to prevent potentially menacing complications, which allows one to conclude that it is necessary to use cerebral oximetry procedures within neu-romonitoring in cardiac surgery. Key words: extracorporeal circulation, cerebral oximetry, neurological dysfunction, cerebral oxygenation.

  16. Complications after cardiac implantable electronic device implantations

    DEFF Research Database (Denmark)

    Kirkfeldt, Rikke Esberg; Johansen, Jens Brock; Nohr, Ellen Aagaard

    2013-01-01

    Complications after cardiac implantable electronic device (CIED) treatment, including permanent pacemakers (PMs), cardiac resynchronization therapy devices with defibrillators (CRT-Ds) or without (CRT-Ps), and implantable cardioverter defibrillators (ICDs), are associated with increased patient...

  17. Hybrid options for treating cardiac disease.

    Science.gov (United States)

    Umakanthan, Ramanan; Leacche, Marzia; Zhao, David X; Gallion, Anna H; Mishra, Prabodh C; Byrne, John G

    2011-01-01

    The options for treating heart disease have greatly expanded during the course of the last 2 1/2 decades with the advent of hybrid technology. The hybrid option for treating cardiac disease implies using the technology of both interventional cardiology and cardiac surgery to treat cardiac disease. This rapidly developing technology has given rise to new and creative techniques to treat cardiac disease involving coronary artery disease, coronary artery disease and cardiac valve disease, and atrial fibrillation. It has also led to the establishment of new procedural suites called hybrid operating rooms that facilitate the integration of technologies of interventional cardiology catheterization laboratories with those of cardiac surgery operating rooms. The development of hybrid options for treating cardiac disease has also greatly augmented teamwork and collaboration between interventional cardiologists and cardiac surgeons. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Sudden Cardiac Arrest (SCA) Risk Assessment

    Science.gov (United States)

    ... HRS Find a Specialist Share Twitter Facebook SCA Risk Assessment Sudden Cardiac Arrest (SCA) occurs abruptly and without ... people of all ages and health conditions. Start Risk Assessment The Sudden Cardiac Arrest (SCA) Risk Assessment Tool ...

  19. Human technology after cardiac epigenesis. Artificial heart versus cardiac transplantation.

    Science.gov (United States)

    Losman, J G

    1977-09-24

    Cardiovascular disease is the chief cause of death in technologically advanced countries and accounts for more than 50% of all deaths in the USA. For a patient with end-stage cardiac failure the only treatment presently available is organ replacement, either by transplantation or by the use of a mechanical heart. Transplantation has demonstrated its value: survival of more than 8 years and restoration of a normal quality of life to patients who were in end-stage cardiac decompensation. However, the prospect of routine clinical application of an artificial heart remains distant. The development of a totally implantable artificial heart still presents a series of challenging engineering problems with regard to strict constraints of size, weight, blood-material compatibility, adaptability of output to demand, efficiency and reliability of the power supply, and safety if nuclear fuel is used. The totally artificial heart is presently not an alternative to the cardiac allograft, but could provide short-term support for patients awaiting cardiac transplantation.

  20. Health Literacy Predicts Cardiac Knowledge Gains in Cardiac Rehabilitation Participants

    Science.gov (United States)

    Mattson, Colleen C.; Rawson, Katherine; Hughes, Joel W.; Waechter, Donna; Rosneck, James

    2015-01-01

    Objective: Health literacy is increasingly recognised as a potentially important patient characteristic related to patient education efforts. We evaluated whether health literacy would predict gains in knowledge after completion of patient education in cardiac rehabilitation. Method: This was a re-post observational analysis study design based on…

  1. ERManI (Endoplasmic Reticulum Class I α-Mannosidase) Is Required for HIV-1 Envelope Glycoprotein Degradation via Endoplasmic Reticulum-associated Protein Degradation Pathway.

    Science.gov (United States)

    Zhou, Tao; Frabutt, Dylan A; Moremen, Kelley W; Zheng, Yong-Hui

    2015-09-04

    Previously, we reported that the mitochondrial translocator protein (TSPO) induces HIV-1 envelope (Env) degradation via the endoplasmic reticulum (ER)-associated protein degradation (ERAD) pathway, but the mechanism was not clear. Here we investigated how the four ER-associated glycoside hydrolase family 47 (GH47) α-mannosidases, ERManI, and ER-degradation enhancing α-mannosidase-like (EDEM) proteins 1, 2, and 3, are involved in the Env degradation process. Ectopic expression of these four α-mannosidases uncovers that only ERManI inhibits HIV-1 Env expression in a dose-dependent manner. In addition, genetic knock-out of the ERManI gene MAN1B1 using CRISPR/Cas9 technology disrupts the TSPO-mediated Env degradation. Biochemical studies show that HIV-1 Env interacts with ERManI, and between the ERManI cytoplasmic, transmembrane, lumenal stem, and lumenal catalytic domains, the catalytic domain plays a critical role in the Env-ERManI interaction. In addition, functional studies show that inactivation of the catalytic sites by site-directed mutagenesis disrupts the ERManI activity. These studies identify ERManI as a critical GH47 α-mannosidase in the ER-associated protein degradation pathway that initiates the Env degradation and suggests that its catalytic domain and enzymatic activity play an important role in this process. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  2. Discovery and progress of direct cardiac reprogramming.

    Science.gov (United States)

    Kojima, Hidenori; Ieda, Masaki

    2017-06-01

    Cardiac disease remains a major cause of death worldwide. Direct cardiac reprogramming has emerged as a promising approach for cardiac regenerative therapy. After the discovery of MyoD, a master regulator for skeletal muscle, other single cardiac reprogramming factors (master regulators) have been sought. Discovery of cardiac reprogramming factors was inspired by the finding that multiple, but not single, transcription factors were needed to generate induced pluripotent stem cells (iPSCs) from fibroblasts. We first reported a combination of cardiac-specific transcription factors, Gata4, Mef2c, and Tbx5 (GMT), that could convert mouse fibroblasts into cardiomyocyte-like cells, which were designated as induced cardiomyocyte-like cells (iCMs). Following our first report of cardiac reprogramming, many researchers, including ourselves, demonstrated an improvement in cardiac reprogramming efficiency, in vivo direct cardiac reprogramming for heart regeneration, and cardiac reprogramming in human cells. However, cardiac reprogramming in human cells and adult fibroblasts remains inefficient, and further efforts are needed. We believe that future research elucidating epigenetic barriers and molecular mechanisms of direct cardiac reprogramming will improve the reprogramming efficiency, and that this new technology has great potential for clinical applications.

  3. Cardiac anatomy and physiology: a review.

    Science.gov (United States)

    Gavaghan, M

    1998-04-01

    This article reviews the normal anatomy and physiology of the heart. Understanding the normal anatomic and physiologic relationships described in this article will help perioperative nurses care for patients who are undergoing cardiac procedures. Such knowledge also assists nurses in educating patients about cardiac procedures and about activities that can prevent, reverse, or improve cardiac illness.

  4. Multimodality imaging to guide cardiac interventional procedures

    NARCIS (Netherlands)

    Tops, Laurens Franciscus

    2010-01-01

    In recent years, a number of new cardiac interventional procedures have been introduced. Catheter ablation procedures for atrial fibrillation (AF) have been refined and are now considered a good treatment option in patients with drug-refractory AF. In cardiac pacing, cardiac resynchronization

  5. Technique for producing cardiac radionuclide motion images

    International Nuclear Information System (INIS)

    Reese, I.C.; Mishkin, F.S.

    1975-01-01

    Sequential frames of different portions of the cardiac cycle are gated into a minicomputer by using an EKG signal recorded onto digital tape simultaneously with imaging information. Serial display of these frames on the computer oscilloscope or projection of 35-mm half frames of these images provides a cardiac motion image with information content adequate for qualitatively assessing cardiac motion. (U.S.)

  6. Optimal Technique in Cardiac Anesthesia Recovery

    NARCIS (Netherlands)

    Svircevic, V.

    2014-01-01

    The aim of this thesis is to evaluate fast-track cardiac anesthesia techniques and investigate their impact on postoperative mortality, morbidity and quality of life. The following topics will be discussed in the thesis. (1.) Is fast track cardiac anesthesia a safe technique for cardiac surgery?

  7. Limited effects of exogenous glucose during severe hypoxia and a lack of hypoxia-stimulated glucose uptake in isolated rainbow trout cardiac muscle

    Science.gov (United States)

    Becker, Tracy A.; DellaValle, Brian; Gesser, Hans; Rodnick, Kenneth J.

    2013-01-01

    SUMMARY We examined whether exogenous glucose affects contractile performance of electrically paced ventricle strips from rainbow trout under conditions known to alter cardiomyocyte performance, ion regulation and energy demands. Physiological levels of d-glucose did not influence twitch force development for aerobic preparations (1) paced at 0.5 or 1.1 Hz, (2) at 15 or 23°C, (3) receiving adrenergic stimulation or (4) during reoxygenation with or without adrenaline after severe hypoxia. Contractile responses to ryanodine, an inhibitor of Ca2+ release from the sarcoplasmic reticulum, were also not affected by exogenous glucose. However, glucose did attenuate the fall in twitch force during severe hypoxia. Glucose uptake was assayed in non-contracting ventricle strips using 2-[3H] deoxy-d-glucose (2-DG) under aerobic and hypoxic conditions, at different incubation temperatures and with different inhibitors. Based upon a lack of saturation of 2-DG uptake and incomplete inhibition of uptake by cytochalasin B and d-glucose, 2-DG uptake was mediated by a combination of facilitated transport and simple diffusion. Hypoxia stimulated lactate efflux sixfold to sevenfold with glucose present, but did not increase 2-DG uptake or reduce lactate efflux in the presence of cytochalasin B. Increasing temperature (14 to 24°C) also did not increase 2-DG uptake, but decreasing temperature (14 to 4°C) reduced 2-DG uptake by 45%. In conclusion, exogenous glucose improves mechanical performance under hypoxia but not under any of the aerobic conditions applied. The extracellular concentration of glucose and cold temperature appear to determine and limit cardiomyocyte glucose uptake, respectively, and together may help define a metabolic strategy that relies predominantly on intracellular energy stores. PMID:23685969

  8. Cardiac tumors: optimal cardiac MR sequences and spectrum of imaging appearances.

    LENUS (Irish Health Repository)

    O'Donnell, David H

    2012-02-01

    OBJECTIVE: This article reviews the optimal cardiac MRI sequences for and the spectrum of imaging appearances of cardiac tumors. CONCLUSION: Recent technologic advances in cardiac MRI have resulted in the rapid acquisition of images of the heart with high spatial and temporal resolution and excellent myocardial tissue characterization. Cardiac MRI provides optimal assessment of the location, functional characteristics, and soft-tissue features of cardiac tumors, allowing accurate differentiation of benign and malignant lesions.

  9. Cardiac-specific overexpression of insulin-like growth factor I (IGF-1) rescues lipopolysaccharide-induced cardiac dysfunction and activation of stress signaling in murine cardiomyocytes.

    Science.gov (United States)

    Zhao, Peng; Turdi, Subat; Dong, Feng; Xiao, Xiaoyan; Su, Guohai; Zhu, Xinglei; Scott, Glenda I; Ren, Jun

    2009-07-01

    Lipopolysaccharide (LPS), a component of the outer membrane of Gram-negative bacteria, plays a key role in cardiac dysfunction in sepsis. Low circulating levels of insulin-like growth factor 1 (IGF-1) are found in sepsis, although the influence of IGF-1 on septic cardiac defect is unknown. This study was designed to examine the impact of IGF-1 on LPS-induced cardiac contractile and intracellular Ca2+ dysfunction, activation of stress signal and endoplasmic reticulum (ER) stress. Mechanical and intracellular Ca2+ properties were examined in cardiomyocytes from Fast Violet B and cardiac-specific IGF-1 overexpression mice treated with or without LPS (4 mg kg(-1), 6 h). Reactive oxygen species (ROS), protein carbonyl formation and apoptosis were measured. Activation of mitogen-activated protein kinase pathways (p38, c-jun N-terminal kinase [JNK] and extracellular signal-related kinase [ERK]), ER stress and apoptotic markers were evaluated using Western blot analysis. Our results revealed decreased peak shortening and maximal velocity of shortening/relengthening and prolonged duration of relengthening in LPS-treated Fast Violet B cardiomyocytes associated with reduced intracellular Ca2+ decay. Accumulation of ROS protein carbonyl and apoptosis were elevated after LPS treatment. Western blot analysis revealed activated p38 and JNK, up-regulated Bax, and the ER stress markers GRP78 and Gadd153 in LPS-treated mouse hearts without any change in ERK and Bcl-2. Total protein expression of p38, JNK, and ERK was unaffected by either LPS or IGF-1. Interestingly, these LPS-induced changes in mechanical and intracellular Ca2+ properties, ROS, protein carbonyl, apoptosis, stress signal activation, and ER stress markers were effectively ablated by IGF-1. In vitro LPS exposure (1 microg mL(-1)) produced cardiomyocyte mechanical dysfunction reminiscent of the in vivo setting, which was alleviated by exogenous IGF-1 (50 nM). These data collectively suggested a beneficial of IGF-1 in

  10. Thapsigargin, a tumor promoter, discharges intracellular Ca2+ stores by specific inhibition of the endoplasmic reticulum Ca2(+)-ATPase

    DEFF Research Database (Denmark)

    Thastrup, Ole; Cullen, P J; Drøbak, B K

    1990-01-01

    . This hypothesis is strongly supported by the demonstration that thapsigargin causes a rapid inhibition of the Ca2(+)-activated ATPase activity of rat liver microsomes, with an identical dose dependence to that seen in whole cell or isolated microsome Ca2+ discharge. The inhibition of the endoplasmic reticulum...

  11. Initiation of GalNAc-type O-glycosylation in the endoplasmic reticulum promotes cancer cell invasiveness

    DEFF Research Database (Denmark)

    Gill, David J; Tham, Keit Min; Chia, Joanne

    2013-01-01

    Invasiveness underlies cancer aggressiveness and is a hallmark of malignancy. Most malignant tumors have elevated levels of Tn, an O-GalNAc glycan. Mechanisms underlying Tn up-regulation and its effects remain unclear. Here we show that Golgi-to-endoplasmic reticulum relocation of polypeptide N-a...

  12. PIN6 auxin transporter at endoplasmic reticulum and plasma membrane mediates auxin homeostasis and organogenesis in Arabidopsis

    Czech Academy of Sciences Publication Activity Database

    Simon, S.; Skůpa, Petr; Viaene, T.; Zwiewka, M.; Tejos, R.; Klíma, Petr; Čarná, Mária; Rolčík, J.; De Rycke, R.; Moreno, I.; Dobrev, Petre; Orellana, A.; Zažímalová, Eva; Friml, J.

    2016-01-01

    Roč. 211, č. 1 (2016), s. 65-74 ISSN 0028-646X R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068; GA ČR(CZ) GA16-10948S Institutional support: RVO:61389030 Keywords : auxin * endoplasmic reticulum (ER) * lateral root Subject RIV: ED - Physiology Impact factor: 7.330, year: 2016

  13. GRP94: An HSP90-like protein specialized for protein folding and quality control in the endoplasmic reticulum

    DEFF Research Database (Denmark)

    Marzec, Michal; Eletto, Davide; Argon, Yair

    2012-01-01

    Glucose-regulated protein 94 is the HSP90-like protein in the lumen of the endoplasmic reticulum and therefore it chaperones secreted and membrane proteins. It has essential functions in development and physiology of multicellular organisms, at least in part because of this unique clientele. GRP94...

  14. Reninoma presenting as cardiac syncope

    Science.gov (United States)

    Tak, Shahid I; Wani, Mohd Lateef; Khan, Khursheed A; Alai, Mohd Sultan; Shera, Altaf Hussain; Ahangar, Abdul G; Khan, Yasir Bashir; Nayeem-ul-Hassan; Irshad, Ifat

    2011-01-01

    Reninoma, a renin-secreting tumor of the juxta-glomerular cells of the kidney, is a rare but surgically treatable cause of secondary hypertension in children. We report a case of reninoma presenting as cardiac syncope with long QTc on electrocardiogram due to hypokalemia. PMID:21677812

  15. Approach to cardiac resyncronization therapy

    DEFF Research Database (Denmark)

    Dobreanu, Dan; Dagres, Nikolaos; Svendsen, Jesper Hastrup

    2012-01-01

    fibrillation and standard criteria for CRT. In 24% of the centres, biventricular pacemaker (CRT-P) is implanted in all situations, unless there is an indication for secondary prevention of sudden cardiac death, while 10% always choose to implant a biventricular defibrillator (CRT-D). There are no clear...

  16. The cardiac patient in Ramadan.

    Science.gov (United States)

    Chamsi-Pasha, Majed; Chamsi-Pasha, Hassan

    2016-01-01

    Ramadan is one of the five fundamental pillars of Islam. During this month, the majority of the 1.6 billion Muslims worldwide observe an absolute fast from dawn to sunset without any drink or food. Our review shows that the impact of fasting during Ramadan on patients with stable cardiac disease is minimal and does not lead to any increase in acute events. Most patients with the stable cardiac disease can fast safely. Most of the drug doses and their regimen are easily manageable during this month and may need not to be changed. Ramadan fasting is a healthy nonpharmacological means for improving cardiovascular risk factors. Most of the Muslims, who suffer from chronic diseases, insist on fasting Ramadan despite being exempted by religion. The Holy Quran specifically exempts the sick from fasting. This is particularly relevant if fasting worsens one's illness or delays recovery. Patients with unstable angina, recent myocardial infarction, uncontrolled hypertension, decompensated heart failure, recent cardiac intervention or cardiac surgery or any debilitating diseases should avoid fasting.

  17. Cardiac abnormalities after subarachnoid hemorrhage

    NARCIS (Netherlands)

    Bilt, I.A.C. van der

    2016-01-01

    Aneurysmal subarachnoid hemorrhage(aSAH) is a devastating neurological disease. During the course of the aSAH several neurological and medical complications may occur. Cardiac abnormalities after aSAH are observed often and resemble stress cardiomyopathy or Tako-tsubo cardiomyopathy(Broken Heart

  18. [Acute cardiac failure in pheochromocytoma.

    DEFF Research Database (Denmark)

    Jønler, Morten; Munk, Kim

    2008-01-01

    Pheochromocytoma (P) is an endocrine catecholamine-secreting tumor. Classical symptoms like hypertension, attacks of sweating, palpitations, headache and palor are related to catecholamine discharge. We provide a case of P in a 71 year-old man presenting with acute cardiac failure, severe reduction...

  19. Response to cardiac resynchronization therapy

    DEFF Research Database (Denmark)

    Versteeg, Henneke; Schiffer, Angélique A; Widdershoven, Jos W

    2009-01-01

    Cardiac resynchronization therapy (CRT) is a promising treatment for a subgroup of patients with advanced congestive heart failure and a prolonged QRS interval. Despite the majority of patients benefiting from CRT, 10-40% of patients do not respond to this treatment and are labeled as nonresponders...

  20. Guide to prosthetic cardiac valves

    International Nuclear Information System (INIS)

    Morse, D.; Steiner, R.M.; Fernandez, J.

    1985-01-01

    This book contains 10 chapters. Some of the chapter titles are: The development of artificial heart valves: Introduction and historical perspective; The radiology of prosthetic heart valves; The evaluation of patients for prosthetic valve implantation; Pathology of cardiac valve replacement; and Bioengineering of mechanical and biological heart valve substitutes

  1. Automatic referral to cardiac rehabilitation.

    Science.gov (United States)

    Fischer, Jane P

    2008-01-01

    The pervasive negative impact of cardiovascular disease in the United States is well documented. Although advances have been made, the campaign to reduce the occurrence, progression, and mortality continues. Determining evidence-based data is only half the battle. Implementing new and updated clinical guidelines into daily practice is a challenging task. Cardiac rehabilitation is an example of a proven intervention whose benefit is hindered through erratic implementation. The American Association of Cardiovascular and Pulmonary Rehabilitation (AACVPR), the American College of Cardiology (ACC), and the American Heart Association (AHA) have responded to this problem by publishing the AACVPR/ACC/AHA 2007 Performance Measures on Cardiac Rehabilitation for Referral to and Delivery of Cardiac Rehabilitation/Secondary Prevention Services. This new national guideline recommends automatic referral to cardiac rehabilitation for every eligible patient (performance measure A-1). This article offers guidance for the initiation of an automatic referral system, including individualizing your protocol with regard to electronic or paper-based order entry structures.

  2. Can cardiac surgery cause hypopituitarism?

    Science.gov (United States)

    Francis, Flverly; Burger, Ines; Poll, Eva Maria; Reineke, Andrea; Strasburger, Christian J; Dohmen, Guido; Gilsbach, Joachim M; Kreitschmann-Andermahr, Ilonka

    2012-03-01

    Apoplexy of pituitary adenomas with subsequent hypopituitarism is a rare but well recognized complication following cardiac surgery. The nature of cardiac on-pump surgery provides a risk of damage to the pituitary because the vascular supply of the pituitary is not included in the cerebral autoregulation. Thus, pituitary tissue may exhibit an increased susceptibility to hypoperfusion, ischemia or intraoperative embolism. After on-pump procedures, patients often present with physical and psychosocial impairments which resemble symptoms of hypopituitarism. Therefore, we analyzed whether on-pump cardiac surgery may cause pituitary dysfunction also in the absence of pre-existing pituitary disease. Twenty-five patients were examined 3-12 months after on-pump cardiac surgery. Basal hormone levels for all four anterior pituitary hormone axes were measured and a short synacthen test and a growth hormone releasing hormone plus arginine (GHRH-ARG)-test were performed. Quality of life (QoL), depression, subjective distress for a specific life event, sleep quality and fatigue were assessed by means of self-rating questionnaires. Hormonal alterations were only slight and no signs of anterior hypopituitarism were found except for an insufficient growth hormone rise in two overweight patients in the GHRH-ARG-test. Psychosocial impairment was pronounced, including symptoms of moderate to severe depression in 9, reduced mental QoL in 8, dysfunctional coping in 6 and pronounced sleep disturbances in 16 patients. Hormone levels did not correlate with psychosocial impairment. On-pump cardiac surgery did not cause relevant hypopituitarism in our sample of patients and does not serve to explain the psychosocial symptoms of these patients.

  3. Endoplasmic reticulum stress is induced in the human placenta during labour.

    Science.gov (United States)

    Veerbeek, J H W; Tissot Van Patot, M C; Burton, G J; Yung, H W

    2015-01-01

    Placental endoplasmic reticulum (ER) stress has been postulated in the pathophysiology of pre-eclampsia (PE) and intrauterine growth restriction (IUGR), but its activation remains elusive. Oxidative stress induced by ischaemia/hypoxia-reoxygenation activates ER stress in vitro. Here, we explored whether exposure to labour represents an in vivo model for the study of acute placental ER stress. ER stress markers, GRP78, P-eIF2α and XBP-1, were significantly higher in laboured placentas than in Caesarean-delivered controls localised mainly in the syncytiotrophoblast. The similarities to changes observed in PE/IUGR placentas suggest exposure to labour can be used to investigate induction of ER stress in pathological placentas. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Friend or foe: Endoplasmic reticulum protein 29 (ERp29) in epithelial cancer

    Science.gov (United States)

    Chen, Shaohua; Zhang, Daohai

    2015-01-01

    The endoplasmic reticulum (ER) protein 29 (ERp29) is a molecular chaperone that plays a critical role in protein secretion from the ER in eukaryotic cells. Recent studies have also shown that ERp29 plays a role in cancer. It has been demonstrated that ERp29 is inversely associated with primary tumor development and functions as a tumor suppressor by inducing cell growth arrest in breast cancer. However, ERp29 has also been reported to promote epithelial cell morphogenesis, cell survival against genotoxic stress and distant metastasis. In this review, we summarize the current understanding on the biological and pathological functions of ERp29 in cancer and discuss the pivotal aspects of ERp29 as “friend or foe” in epithelial cancer. PMID:25709888

  5. VCP and ATL1 regulate endoplasmic reticulum and protein synthesis for dendritic spine formation.

    Science.gov (United States)

    Shih, Yu-Tzu; Hsueh, Yi-Ping

    2016-03-17

    Imbalanced protein homeostasis, such as excessive protein synthesis and protein aggregation, is a pathogenic hallmark of a range of neurological disorders. Here, using expression of mutant proteins, a knockdown approach and disease mutation knockin mice, we show that VCP (valosin-containing protein), together with its cofactor P47 and the endoplasmic reticulum (ER) morphology regulator ATL1 (Atlastin-1), regulates tubular ER formation and influences the efficiency of protein synthesis to control dendritic spine formation in neurons. Strengthening the significance of protein synthesis in dendritic spinogenesis, the translation blocker cyclohexamide and the mTOR inhibitor rapamycin reduce dendritic spine density, while a leucine supplement that increases protein synthesis ameliorates the dendritic spine defects caused by Vcp and Atl1 deficiencies. Because VCP and ATL1 are the causative genes of several neurodegenerative and neurodevelopmental disorders, we suggest that impaired ER formation and inefficient protein synthesis are significant in the pathogenesis of multiple neurological disorders.

  6. Pekinenin E Inhibits the Growth of Hepatocellular Carcinoma by Promoting Endoplasmic Reticulum Stress Mediated Cell Death

    Directory of Open Access Journals (Sweden)

    Lu Fan

    2017-06-01

    Full Text Available Hepatocellular carcinoma (HCC is a malignant primary liver cancer with poor prognosis. In the present study, we report that pekinenin E (PE, a casbane diterpenoid derived from the roots of Euphorbia pekinensis, has a strong antitumor activity against human HCC cells both in vitro and in vivo. PE suppressed the growth of human HCC cells Hep G2 and SMMC-7721. In addition, PE-mediated endoplasmic reticulum (ER stress caused increasing expressions of C/EBP homologous protein (CHOP, leading to apoptosis in HCC cells both in vitro and in vivo. Inhibition of ER stress with CHOP small interfering RNA or 4-phenyl-butyric acid partially reversed PE-induced cell death. Furthermore, PE induced S cell cycle arrest, which could also be partially reversed by CHOP knockdown. In all, these findings suggest that PE causes ER stress-associated cell death and cell cycle arrest, and it may serve as a potent agent for curing human HCC.

  7. Lipid Droplet Formation Is Dispensable for Endoplasmic Reticulum-associated Degradation*

    Science.gov (United States)

    Olzmann, James A.; Kopito, Ron R.

    2011-01-01

    Proteins that fail to fold or assemble in the endoplasmic reticulum (ER) are destroyed by cytoplasmic proteasomes through a process known as ER-associated degradation. Substrates of this pathway are initially sequestered within the ER lumen and must therefore be dislocated across the ER membrane to be degraded. It has been proposed that generation of bicellar structures during lipid droplet formation may provide an “escape hatch” through which misfolded proteins, toxins, and viruses can exit the ER. We have directly tested this hypothesis by exploiting yeast strains defective in lipid droplet formation. Our data demonstrate that lipid droplet formation is dispensable for the dislocation of a plant toxin and the degradation of both soluble and integral membrane glycoproteins. PMID:21693705

  8. The plant membrane surrounding powdery mildew haustoria shares properties with the endoplasmic reticulum membrane

    DEFF Research Database (Denmark)

    Kwaaitaal, Mark Adrianus Cornelis J; Nielsen, Mads Eggert; Böhlenius, Henrik

    2017-01-01

    Many filamentous plant pathogens place specialized feeding structures, called haustoria, inside living host cells. As haustoria grow, they are believed to manipulate plant cells to generate a specialized, still enigmatic extrahaustorial membrane (EHM) around them. Here, we focused on revealing...... properties of the EHM. With the help of membranespecific dyes and transient expression of membrane-associated proteins fused to fluorescent tags, we studied the nature of the EHM generated by barley leaf epidermal cells around powdery mildew haustoria. Observations suggesting that endoplasmic reticulum (ER...... that it is not a continuum of the ER. Furthermore, GDP-locked Sar1 and a nucleotide-free RabD2a, which block ER to Golgi exit, did not hamper haustorium formation. These results indicated that the EHM shares features with the plant ER membrane, but that the EHM membrane is not dependent on conventional secretion...

  9. Flurbiprofen ameliorated obesity by attenuating leptin resistance induced by endoplasmic reticulum stress.

    Science.gov (United States)

    Hosoi, Toru; Yamaguchi, Rie; Noji, Kikuko; Matsuo, Suguru; Baba, Sachiko; Toyoda, Keisuke; Suezawa, Takahiro; Kayano, Takaaki; Tanaka, Shinpei; Ozawa, Koichiro

    2014-03-01

    Endoplasmic reticulum (ER) stress, caused by the accumulation of unfolded proteins, is involved in the development of obesity. We demonstrated that flurbiprofen, a nonsteroidal anti-inflammatory drug (NSAID), exhibited chaperone activity, which reduced protein aggregation and alleviated ER stress-induced leptin resistance, characterized by insensitivity to the actions of the anti-obesity hormone leptin. This result was further supported by flurbiprofen attenuating high-fat diet-induced obesity in mice. The other NSAIDs tested did not exhibit such effects, which suggested that this anti-obesity action is mediated independent of NSAIDs. Using ferriteglycidyl methacrylate beads, we identified aldehyde dehydrogenase as the target of flurbiprofen, but not of the other NSAIDs. These results suggest that flurbiprofen may have unique pharmacological properties that reduce the accumulation of unfolded proteins and may represent a new class of drug for the fundamental treatment of obesity.

  10. Renal endoplasmic reticulum stress is coupled to impaired autophagy in a mouse model of GSD Ia.

    Science.gov (United States)

    Farah, Benjamin L; Landau, Dustin J; Wu, Yajun; Sinha, Rohit A; Loh, Alwin; Bay, Boon-Huat; Koeberl, Dwight D; Yen, Paul M

    2017-11-01

    GSD Ia (von Gierke Disease, Glycogen Storage Disease Type Ia) is a devastating genetic disorder with long-term sequelae, such as non-alcoholic fatty liver disease and renal failure. Down-regulated autophagy is involved in the development of hepatic metabolic dysfunction in GSD Ia; however, the role of autophagy in the renal pathology is unknown. Here we show that autophagy is impaired and endoplasmic reticulum (ER) stress is increased in the kidneys of a mouse model of GSD Ia. Induction of autophagy by rapamycin also reduces this ER stress. Taken together, these results show an additional role for autophagy down-regulation in the pathogenesis of GSD Ia, and provide further justification for the use of autophagy modulators in GSD Ia. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Multivesicular body formation enhancement and exosome release during endoplasmic reticulum stress.

    Science.gov (United States)

    Kanemoto, Soshi; Nitani, Ryota; Murakami, Tatsuhiko; Kaneko, Masayuki; Asada, Rie; Matsuhisa, Koji; Saito, Atsushi; Imaizumi, Kazunori

    2016-11-11

    The endoplasmic reticulum (ER) plays a pivotal role in maintaining cellular homeostasis. However, numerous environmental and genetic factors give rise to ER stress by inducing an accumulation of unfolded proteins. Under ER stress conditions, cells initiate the unfolded protein response (UPR). Here, we demonstrate a novel aspect of the UPR by electron microscopy and immunostaining analyses, whereby multivesicular body (MVB) formation was enhanced after ER stress. This MVB formation was influenced by inhibition of ER stress transducers inositol required enzyme 1 (IRE1) and PKR-like ER kinase (PERK). Furthermore, exosome release was also increased during ER stress. However, in IRE1 or PERK deficient cells, exosome release was not upregulated, indicating that IRE1- and PERK-mediated pathways are involved in ER stress-dependent exosome release. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Bortezomib initiates endoplasmic reticulum stress, elicits autophagy and death in Echinococcus granulosus larval stage

    Science.gov (United States)

    Nicolao, María Celeste; Loos, Julia A.; Rodriguez Rodrigues, Christian; Beas, Viviana

    2017-01-01

    Cystic echinococcosis (CE) is a worldwide distributed helminthic zoonosis caused by Echinococcus granulosus. Benzimidazole derivatives are currently the only drugs for chemotherapeutic treatment of CE. However, their low efficacy and the adverse effects encourage the search for new therapeutic targets. We evaluated the in vitro efficacy of Bortezomib (Bz), a proteasome inhibitor, in the larval stage of the parasite. After 96 h, Bz showed potent deleterious effects at a concentration of 5 μM and 0.5 μM in protoscoleces and metacestodes, respectively (P Echinococcus cell viability, we evaluated the efficacy of Bz in combination with rapamycin and a synergistic cytotoxic effect on protoscolex viability was observed when both drugs were used together. In conclusion, our findings demonstrated that Bz induced endoplasmic reticulum stress, autophagy and subsequent death allowing to identify unstudied parasite-host pathways that could provide a new insight for control of parasitic diseases. PMID:28817601

  13. Dark matter in the Reticulum II dSph: a radio search

    Science.gov (United States)

    Regis, Marco; Richter, Laura; Colafrancesco, Sergio

    2017-07-01

    We present a deep radio search in the Reticulum II dwarf spheroidal (dSph) galaxy performed with the Australia Telescope Compact Array. Observations were conducted at 16 cm wavelength, with an rms sensitivity of 0.01 mJy/beam, and with the goal of searching for synchrotron emission induced by annihilation or decay of weakly interacting massive particles (WIMPs). Data were complemented with observations on large angular scales taken with the KAT-7 telescope. We find no evidence for a diffuse emission from the dSph and we derive competitive bounds on the WIMP properties. In addition, we detect more than 200 new background radio sources. Among them, we show there are two compelling candidates for being the radio counterpart of the possible γ-ray emission reported by other groups using Fermi-LAT data.

  14. Dark matter in the Reticulum II dSph: a radio search

    International Nuclear Information System (INIS)

    Regis, Marco; Richter, Laura; Colafrancesco, Sergio

    2017-01-01

    We present a deep radio search in the Reticulum II dwarf spheroidal (dSph) galaxy performed with the Australia Telescope Compact Array. Observations were conducted at 16 cm wavelength, with an rms sensitivity of 0.01 mJy/beam, and with the goal of searching for synchrotron emission induced by annihilation or decay of weakly interacting massive particles (WIMPs). Data were complemented with observations on large angular scales taken with the KAT-7 telescope. We find no evidence for a diffuse emission from the dSph and we derive competitive bounds on the WIMP properties. In addition, we detect more than 200 new background radio sources. Among them, we show there are two compelling candidates for being the radio counterpart of the possible γ-ray emission reported by other groups using Fermi-LAT data.

  15. CCPG1, a cargo receptor required for reticulophagy and endoplasmic reticulum proteostasis.

    Science.gov (United States)

    Smith, Matthew D; Wilkinson, Simon

    2018-06-19

    The importance of selective macroautophagy/autophagy in cellular health is increasingly evident. The selective degradation of portions of the endoplasmic reticulum (ER), or reticulophagy, is an emerging example but requires further mechanistic detail and broad evidence of physiological relevance. In a recent study, we identified CCPG1, an ER-resident transmembrane protein that can bind to Atg8-family proteins and, independently and discretely, to RB1CC1/FIP200. Both of these interactions are required to facilitate CCPG1's function as a reticulophagy cargo receptor. CCPG1 transcripts are inducible by ER stress, providing a direct link between ER stress and reticulophagy. In vivo, CCPG1 prevents the hyper-accumulation of insoluble protein within the ER lumen of pancreatic acinar cells and alleviates ER stress. Accordingly, CCPG1 loss sensitizes the exocrine pancreas to tissue injury.

  16. Endoplasmic reticulum transport of glutathione by Sec61 is regulated by Ero1 and Bip

    DEFF Research Database (Denmark)

    Ponsero, Alise J.; Igbaria, Aeid; Darch, Maxwell A.

    2017-01-01

    In the endoplasmic reticulum (ER), Ero1 catalyzes disulfide bond formation and promotes glutathione (GSH) oxidation to GSSG. Since GSSG cannot be reduced in the ER, maintenance of the ER glutathione redox state and levels likely depends on ER glutathione import and GSSG export. We used quantitative...... oxidation through Ero1 reductive activation, which inhibits glutathione import in a negative regulatory loop. During ER stress, transport is activated by UPR-dependent Ero1 induction, and cytosolic glutathione levels increase. Thus, the ER redox poise is tuned by reciprocal control of glutathione import...... by reduction, causing Bip oxidation and inhibition of glutathione transport. Coupling of glutathione ER import to Ero1 activation provides a basis for glutathione ER redox poise maintenance....

  17. Cyclosporine A-sensitive, cyclophilin B-dependent endoplasmic reticulum-associated degradation.

    Directory of Open Access Journals (Sweden)

    Riccardo Bernasconi

    2010-09-01

    Full Text Available Peptidyl-prolyl cis/trans isomerases (PPIs catalyze cis/trans isomerization of peptide bonds preceding proline residues. The involvement of PPI family members in protein refolding has been established in test tube experiments. Surprisingly, however, no data is available on the involvement of endoplasmic reticulum (ER-resident members of the PPI family in protein folding, quality control or disposal in the living cell. Here we report that the immunosuppressive drug cyclosporine A (CsA selectively inhibits the degradation of a subset of misfolded proteins generated in the ER. We identify cyclophilin B (CyPB as the ER-resident target of CsA that catalytically enhances disposal from the ER of ERAD-L(S substrates containing cis proline residues. Our manuscript presents the first evidence for enzymatic involvement of a PPI in protein quality control in the ER of living cells.

  18. Cyclosporine A-Sensitive, Cyclophilin B-Dependent Endoplasmic Reticulum-Associated Degradation

    Science.gov (United States)

    Luban, Jeremy; Molinari, Maurizio

    2010-01-01

    Peptidyl-prolyl cis/trans isomerases (PPIs) catalyze cis/trans isomerization of peptide bonds preceding proline residues. The involvement of PPI family members in protein refolding has been established in test tube experiments. Surprisingly, however, no data is available on the involvement of endoplasmic reticulum (ER)-resident members of the PPI family in protein folding, quality control or disposal in the living cell. Here we report that the immunosuppressive drug cyclosporine A (CsA) selectively inhibits the degradation of a subset of misfolded proteins generated in the ER. We identify cyclophilin B (CyPB) as the ER-resident target of CsA that catalytically enhances disposal from the ER of ERAD-LS substrates containing cis proline residues. Our manuscript presents the first evidence for enzymatic involvement of a PPI in protein quality control in the ER of living cells. PMID:20927389

  19. Management of the endoplasmic reticulum stress by activation of the heat shock response in yeast

    DEFF Research Database (Denmark)

    Hou, Jin; Tang, Hongting; Liu, Zihe

    2014-01-01

    In yeast Saccharomyces cerevisiae, accumulation of misfolded proteins in the endoplasmic reticulum (ER) causes ER stress and activates the unfolded protein response (UPR), which is mediated by Hac1p. The heat shock response (HSR) mediated by Hsf1p, mainly regulates cytosolic processes and protects...... the cell from stresses. Here, we find that a constitutive activation of the HSR could increase ER stress resistance in both wild-type and UPR-deficient cells. Activation of HSR decreased UPR activation in the WT (as shown by the decreased HAC1 mRNA splicing). We analyzed the genome-wide transcriptional...... response in order to propose regulatory mechanisms that govern the interplay between UPR and HSR and followed up for the hypotheses by experiments in vivo and in vitro. Interestingly, we found that the regulation of ER stress response via HSR is (1) only partially dependent on over-expression of Kar2p (ER...

  20. Fluorescence methods for analysis of interactions between Ca(2+) signaling, lysosomes, and endoplasmic reticulum.

    Science.gov (United States)

    Prole, David L; López-Sanjurjo, Cristina I; Tovey, Stephen C; Taylor, Colin W

    2015-01-01

    The endoplasmic reticulum (ER) is both the major source of intracellular Ca(2+) for cell signaling and the organelle that forms the most extensive contacts with the plasma membrane and other organelles. Lysosomes fulfill important roles in degrading cellular materials and in cholesterol handling, but they also contribute to Ca(2+) signaling by both releasing and sequestering Ca(2+). Interactions between ER and other Ca(2+)-transporting membranes, notably mitochondria and the plasma membrane, often occur at sites where the two membranes are closely apposed, allowing local Ca(2+) signaling between them. These interactions are often facilitated by scaffold proteins. Recent evidence suggests similar local interactions between ER and lysosomes. We describe simple fluorescence-based methods that allow the interplay between Ca(2+) signals, the ER, and lysosomes to be examined. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Mechanisms of Alcohol-Induced Endoplasmic Reticulum Stress and Organ Injuries

    Directory of Open Access Journals (Sweden)

    Cheng Ji

    2012-01-01

    Full Text Available Alcohol is readily distributed throughout the body in the blood stream and crosses biological membranes, which affect virtually all biological processes inside the cell. Excessive alcohol consumption induces numerous pathological stress responses, part of which is endoplasmic reticulum (ER stress response. ER stress, a condition under which unfolded/misfolded protein accumulates in the ER, contributes to alcoholic disorders of major organs such as liver, pancreas, heart, and brain. Potential mechanisms that trigger the alcoholic ER stress response are directly or indirectly related to alcohol metabolism, which includes toxic acetaldehyde and homocysteine, oxidative stress, perturbations of calcium or iron homeostasis, alterations of S-adenosylmethionine to S-adenosylhomocysteine ratio, and abnormal epigenetic modifications. Interruption of the ER stress triggers is anticipated to have therapeutic benefits for alcoholic disorders.

  2. Trafficking of endoplasmic reticulum-retained recombinant proteins is unpredictable in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Thomas eDe Meyer

    2014-09-01

    Full Text Available A wide variety of recombinant proteins has been produced in the dicot model plant, Arabidopsis thaliana. Many of these proteins are targeted for secretion by means of an N terminal endoplasmic reticulum (ER signal peptide. In addition, they can also be designed for ER retention by adding a C terminal H/KDEL-tag. Despite extensive knowledge of the protein trafficking pathways, the final protein destination, especially of such H/KDEL-tagged recombinant proteins, is unpredictable. In this respect, glycoproteins are ideal study objects. Microscopy experiments reveal their deposition pattern and characterization of their N-glycans aids in elucidating the trafficking. Here, we combine microscopy and N glycosylation data generated in Arabidopsis leaves and seeds, and highlight the lack of a decent understanding of heterologous protein trafficking.

  3. HMGB1 induces an inflammatory response in endothelial cells via the RAGE-dependent endoplasmic reticulum stress pathway

    International Nuclear Information System (INIS)

    Luo, Ying; Li, Shu-Jun; Yang, Jian; Qiu, Yuan-Zhen; Chen, Fang-Ping

    2013-01-01

    Highlights: •Mechanisms of inflammatory response induced by HMGB1 are incompletely understood. •We found that endoplasmic reticulum stress mediate the inflammatory response induced by HMGB1. •RAGE-mediated ERS pathways are involved in those processes. •We reported a new mechanism for HMGB1 induced inflammatory response. -- Abstract: The high mobility group 1B protein (HMGB1) mediates chronic inflammatory responses in endothelial cells, which play a critical role in atherosclerosis. However, the underlying mechanism is unknown. The goal of our study was to identify the effects of HMGB1 on the RAGE-induced inflammatory response in endothelial cells and test the possible involvement of the endoplasmic reticulum stress pathway. Our results showed that incubation of endothelial cells with HMGB1 (0.01–1 μg/ml) for 24 h induced a dose-dependent activation of endoplasmic reticulum stress transducers, as assessed by PERK and IRE1 protein expression. Moreover, HMGB1 also promoted nuclear translocation of ATF6. HMGB1-mediated ICAM-1 and P-selectin production was dramatically suppressed by PERK siRNA or IRE1 siRNA. However, non-targeting siRNA had no such effects. HMGB1-induced increases in ICAM-1 and P-selectin expression were also inhibited by a specific eIF2α inhibitor (salubrinal) and a specific JNK inhibitor (SP600125). Importantly, a blocking antibody specifically targeted against RAGE (anti-RAGE antibody) decreased ICAM-1, P-selectin and endoplasmic reticulum stress molecule (PERK, eIF2α, IRE1 and JNK) protein expression levels. Collectively, these novel findings suggest that HMGB1 promotes an inflammatory response by inducing the expression of ICAM-1 and P-selectin via RAGE-mediated stimulation of the endoplasmic reticulum stress pathway

  4. Glucose-6-phosphate reduces calcium accumulation in rat brain endoplasmic reticulum

    Directory of Open Access Journals (Sweden)

    Jeffrey Thomas Cole

    2012-04-01

    Full Text Available Brain cells expend large amounts of energy sequestering calcium (Ca2+, while loss of Ca2+ compartmentalization leads to cell damage or death. Upon cell entry, glucose is converted to glucose-6-phosphate (G6P, a parent substrate to several metabolic major pathways, including glycolysis. In several tissues, G6P alters the ability of the endoplasmic reticulum to sequester Ca2+. This led to the hypothesis that G6P regulates Ca2+ accumulation by acting as an endogenous ligand for sarco-endoplasmic reticulum calcium ATPase (SERCA. Whole brain ER microsomes were pooled from adult male Sprague-Dawley rats. Using radio-isotopic assays, 45Ca2+ accumulation was quantified following incubation with increasing amounts of G6P, in the presence or absence of thapsigargin, a potent SERCA inhibitor. To qualitatively assess SERCA activity, the simultaneous release of inorganic phosphate (Pi coupled with Ca2+ accumulation was quantified. Addition of G6P significantly and decreased Ca2+ accumulation in a dose-dependent fashion (1-10 mM. The reduction in Ca2+ accumulation was not significantly different that seen with addition of thapsigargin. Addition of glucose-1-phosphate or fructose-6-phosphate, or other glucose metabolic pathway intermediates, had no effect on Ca2+ accumulation. Further, the release of Pi was markedly decreased, indicating G6P-mediated SERCA inhibition as the responsible mechanism for reduced Ca2+ uptake. Simultaneous addition of thapsigargin and G6P did decrease inorganic phosphate in comparison to either treatment alone, which suggests that the two treatments have different mechanisms of action. Therefore, G6P may be a novel, endogenous regulator of SERCA activity. Additionally, pathological conditions observed during disease states that disrupt glucose homeostasis, may be attributable to Ca2+ dystasis caused by altered G6P regulation of SERCA activity

  5. Long-chain bases from sea cucumber mitigate endoplasmic reticulum stress and inflammation in obesity mice

    Directory of Open Access Journals (Sweden)

    Shiwei Hu

    2017-07-01

    Full Text Available Endoplasmic reticulum (ER stress and inflammation can induce hyperglycemia. Long-chain bases (LCBs from sea cucumber exhibit antihyperglycemic activities. However, their effects on ER stress and inflammation are unknown. We investigated the effects of LCBs on ER stress and inflammatory response in high-fat, fructose diet-induced obesity mice. Reactive oxygen species and free fatty acids were measured. Inflammatory cytokines in serum and their mRNA expressions in epididymal adipose tissues were investigated. Hepatic ER stress-related key genes were detected. c-Jun NH2-terminal kinase and nuclear factor κB inflammatory pathways were also evaluated in the liver. Results showed that LCBs reduced serum and hepatic reactive oxygen species and free fatty acids concentrations. LCBs decreased serum proinflammatory cytokines levels, namely interleukin (IL-1β, tumor necrosis factor-α, IL-6, macrophage inflammatory protein 1, and c-reactive protein, and increased anti-inflammatory cytokine IL-10 concentration. The mRNA and protein expressions of these cytokines in epididymal adipose tissues were regulated by LCBs as similar to their circulatory contents. LCBs inhibited phosphorylated c-Jun NH2-terminal kinase and inhibitor κ kinase β, and nuclear factor κB nuclear translocation. LCBs also inhibited mRNA expression of ER stress markers glucose regulated protein, activating transcription factor 6, double-stranded RNA-activated protein kinase-like endoplasmic reticulum kinase, and X-box binding protein 1, and phosphorylation of eukaryotic initiation factor-α and inositol requiring enzyme 1α. These results indicate that LCBs can alleviate ER stress and inflammatory response. Nutritional supplementation with LCBs may offer an adjunctive therapy for RE stress-associated inflammation.

  6. Tributyltin-induced endoplasmic reticulum stress and its Ca2+-mediated mechanism

    International Nuclear Information System (INIS)

    Isomura, Midori; Kotake, Yaichiro; Masuda, Kyoichi; Miyara, Masatsugu; Okuda, Katsuhiro; Samizo, Shigeyoshi; Sanoh, Seigo; Hosoi, Toru; Ozawa, Koichiro; Ohta, Shigeru

    2013-01-01

    Organotin compounds, especially tributyltin chloride (TBT), have been widely used in antifouling paints for marine vessels, but exhibit various toxicities in mammals. The endoplasmic reticulum (ER) is a multifunctional organelle that controls post-translational modification and intracellular Ca 2+ signaling. When the capacity of the quality control system of ER is exceeded under stress including ER Ca 2+ homeostasis disruption, ER functions are impaired and unfolded proteins are accumulated in ER lumen, which is called ER stress. Here, we examined whether TBT causes ER stress in human neuroblastoma SH-SY5Y cells. We found that 700 nM TBT induced ER stress markers such as CHOP, GRP78, spliced XBP1 mRNA and phosphorylated eIF2α. TBT also decreased the cell viability both concentration- and time-dependently. Dibutyltin and monobutyltin did not induce ER stress markers. We hypothesized that TBT induces ER stress via Ca 2+ depletion, and to test this idea, we examined the effect of TBT on intracellular Ca 2+ concentration using fura-2 AM, a Ca 2+ fluorescent probe. TBT increased intracellular Ca 2+ concentration in a TBT-concentration-dependent manner, and Ca 2+ increase in 700 nM TBT was mainly blocked by 50 μM dantrolene, a ryanodine receptor antagonist (about 70% inhibition). Dantrolene also partially but significantly inhibited TBT-induced GRP78 expression and cell death. These results suggest that TBT increases intracellular Ca 2+ concentration by releasing Ca 2+ from ER, thereby causing ER stress. - Highlights: • We established that tributyltin induces endoplasmic reticulum (ER) stress. • Tributyltin induces ER stress markers in a concentration-dependent manner. • Tributyltin increases Ca 2+ release from ER, thereby causing ER stress. • Dibutyltin and monobutyltin did not increase GRP78 or intracellular Ca 2+

  7. Sarco/Endoplasmic reticulum Ca2+-ATPases (SERCA contribute to GPCR-mediated taste perception.

    Directory of Open Access Journals (Sweden)

    Naoko Iguchi

    Full Text Available The sense of taste is important for providing animals with valuable information about the qualities of food, such as nutritional or harmful nature. Mammals, including humans, can recognize at least five primary taste qualities: sweet, umami (savory, bitter, sour, and salty. Recent studies have identified molecules and mechanisms underlying the initial steps of tastant-triggered molecular events in taste bud cells, particularly the requirement of increased cytosolic free Ca(2+ concentration ([Ca(2+](c for normal taste signal transduction and transmission. Little, however, is known about the mechanisms controlling the removal of elevated [Ca(2+](c from the cytosol of taste receptor cells (TRCs and how the disruption of these mechanisms affects taste perception. To investigate the molecular mechanism of Ca(2+ clearance in TRCs, we sought the molecules involved in [Ca(2+](c regulation using a single-taste-cell transcriptome approach. We found that Serca3, a member of the sarco/endoplasmic reticulum Ca(2+-ATPase (SERCA family that sequesters cytosolic Ca(2+ into endoplasmic reticulum, is exclusively expressed in sweet/umami/bitter TRCs, which rely on intracellular Ca(2+ release for signaling. Serca3-knockout (KO mice displayed significantly increased aversive behavioral responses and greater gustatory nerve responses to bitter taste substances but not to sweet or umami taste substances. Further studies showed that Serca2 was mainly expressed in the T1R3-expressing sweet and umami TRCs, suggesting that the loss of function of Serca3 was possibly compensated by Serca2 in these TRCs in the mutant mice. Our data demonstrate that the SERCA family members play an important role in the Ca(2+ clearance in TRCs and that mutation of these proteins may alter bitter and perhaps sweet and umami taste perception.

  8. Tributyltin-induced endoplasmic reticulum stress and its Ca{sup 2+}-mediated mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Isomura, Midori; Kotake, Yaichiro, E-mail: yaichiro@hiroshima-u.ac.jp; Masuda, Kyoichi; Miyara, Masatsugu; Okuda, Katsuhiro; Samizo, Shigeyoshi; Sanoh, Seigo; Hosoi, Toru; Ozawa, Koichiro; Ohta, Shigeru

    2013-10-01

    Organotin compounds, especially tributyltin chloride (TBT), have been widely used in antifouling paints for marine vessels, but exhibit various toxicities in mammals. The endoplasmic reticulum (ER) is a multifunctional organelle that controls post-translational modification and intracellular Ca{sup 2+} signaling. When the capacity of the quality control system of ER is exceeded under stress including ER Ca{sup 2+} homeostasis disruption, ER functions are impaired and unfolded proteins are accumulated in ER lumen, which is called ER stress. Here, we examined whether TBT causes ER stress in human neuroblastoma SH-SY5Y cells. We found that 700 nM TBT induced ER stress markers such as CHOP, GRP78, spliced XBP1 mRNA and phosphorylated eIF2α. TBT also decreased the cell viability both concentration- and time-dependently. Dibutyltin and monobutyltin did not induce ER stress markers. We hypothesized that TBT induces ER stress via Ca{sup 2+} depletion, and to test this idea, we examined the effect of TBT on intracellular Ca{sup 2+} concentration using fura-2 AM, a Ca{sup 2+} fluorescent probe. TBT increased intracellular Ca{sup 2+} concentration in a TBT-concentration-dependent manner, and Ca{sup 2+} increase in 700 nM TBT was mainly blocked by 50 μM dantrolene, a ryanodine receptor antagonist (about 70% inhibition). Dantrolene also partially but significantly inhibited TBT-induced GRP78 expression and cell death. These results suggest that TBT increases intracellular Ca{sup 2+} concentration by releasing Ca{sup 2+} from ER, thereby causing ER stress. - Highlights: • We established that tributyltin induces endoplasmic reticulum (ER) stress. • Tributyltin induces ER stress markers in a concentration-dependent manner. • Tributyltin increases Ca{sup 2+} release from ER, thereby causing ER stress. • Dibutyltin and monobutyltin did not increase GRP78 or intracellular Ca{sup 2+}.

  9. The glutathione mimic ebselen inhibits oxidative stress but not endoplasmic reticulum stress in endothelial cells.

    Science.gov (United States)

    Ahwach, Salma Makhoul; Thomas, Melanie; Onstead-Haas, Luisa; Mooradian, Arshag D; Haas, Michael J

    2015-08-01

    Reactive oxygen species are associated with cardiovascular disease, diabetes, and atherosclerosis, yet the use of antioxidants in clinical trials has been ineffective at improving outcomes. In endothelial cells, high-dextrose-induced oxidative stress and endoplasmic reticulum stress promote endothelial dysfunction leading to the recruitment and activation of peripheral blood lymphocytes and the breakdown of barrier function. Ebselen, a glutathione peroxidase 1 (GPX1) mimic, has been shown to improve β-cell function in diabetes and prevent atherosclerosis. To determine if ebselen inhibits both oxidative stress and endoplasmic reticulum (ER) stress in endothelial cells, we examined its effects in human umbilical vein endothelial cells (HUVEC) and human coronary artery endothelial cells (HCAEC) with and without high-dextrose. Oxidative stress and ER stress were measured by 2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo[1,2-A]pyrazin-3-one hydrochloride chemiluminescence and ER stress alkaline phosphatase assays, respectively. GPX1 over-expression and knockdown were performed by transfecting cells with a GPX1 expression construct or a GPX1-specific siRNA, respectively. Ebselen inhibited dextrose-induced oxidative stress but not ER stress in both HUVEC and HCAEC. Ebselen also had no effect on tunicamycin-induced ER stress in HCAEC. Furthermore, augmentation of GPX1 activity directly by sodium selenite supplementation or transfection of a GPX1 expression plasmid decreased dextrose-induced oxidative stress but not ER stress, while GPX1 knockout enhanced oxidative stress but had no effect on ER stress. These results suggest that ebselen targets only oxidative stress but not ER stress. Copyright © 2015. Published by Elsevier Inc.

  10. Ebselen alters cellular oxidative status and induces endoplasmic reticulum stress in rat hippocampal astrocytes.

    Science.gov (United States)

    Santofimia-Castaño, Patricia; Izquierdo-Alvarez, Alicia; de la Casa-Resino, Irene; Martinez-Ruiz, Antonio; Perez-Lopez, Marcos; Portilla, Juan C; Salido, Gines M; Gonzalez, Antonio

    2016-05-16

    Ebselen (2-phenyl-1,2-benzisoselenazol-3(2H)-one) is an organoselenium radical scavenger compound, which has strong antioxidant and anti-inflammatory effects. Because of its properties, it may be protective against injury to the nervous tissue. However, evidence suggests that its glutathione peroxidase activity could underlie certain deleterious actions on cell physiology. In this study we have analyzed the effect of ebselen on rat hippocampal astrocytes in culture. Cellular oxidative status, cytosolic free-Ca(2+) concentration ([Ca(2+)]c), setting of endoplasmic reticulum stress and phosphorylation of glial fibrillary acidic protein and major mitogen-activated protein kinases were analyzed. Our results show that ebselen induced a concentration-dependent increase in the generation of reactive oxygen species in the mitochondria. We observed a concentration-dependent increase in global cysteine oxidation and in the level of malondialdehyde in the presence of ebselen. We also detected increases in catalase, glutathione S-transferase and glutathione reductase activity. Ebselen also evoked a concentration-dependent increase in [Ca(2+)]c. Moreover, we observed a concentration-dependent increase in the phosphorylation of the unfolded protein response markers, eukaryotic translation initiation factor 2α and X-box binding protein 1. Finally, ebselen also induced an increase in the phosphorylation of glial fibrillary acidic protein, SAPK/JNK, p38 MAPK and p44/42 MAPK. Our results provide strong evidence that implicate endoplasmic reticulum stress and activation of crucial mitogen-activated protein kinases in an oxidative damage of cells in the presence of ebselen. The compound thus might exert deleterious actions on astrocyte physiology that could compromise their function. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  11. ILDR2: an endoplasmic reticulum resident molecule mediating hepatic lipid homeostasis.

    Directory of Open Access Journals (Sweden)

    Kazuhisa Watanabe

    Full Text Available Ildr2, a modifier of diabetes susceptibility in obese mice, is expressed in most organs, including islets and hypothalamus, with reduced levels in livers of diabetes-susceptible B6.DBA mice congenic for a 1.8 Mb interval of Chromosome 1. In hepatoma and neuronal cells, ILDR2 is primarily located in the endoplasmic reticulum membrane. We used adenovirus vectors that express shRNA or are driven by the CMV promoter, respectively, to knockdown or overexpress Ildr2 in livers of wild type and ob/ob mice. Livers in knockdown mice were steatotic, with increased hepatic and circulating triglycerides and total cholesterol. Increased circulating VLDL, without reduction in triglyceride clearance suggests an effect of reduced hepatic ILDR2 on hepatic cholesterol clearance. In animals that overexpress Ildr2, hepatic triglyceride and total cholesterol levels were reduced, and strikingly so in ob/ob mice. There were no significant changes in body weight, energy expenditure or glucose/insulin homeostasis in knockdown or overexpressing mice. Knockdown mice showed reduced expression of genes mediating synthesis and oxidation of hepatic lipids, suggesting secondary suppression in response to increased hepatic lipid content. In Ildr2-overexpressing ob/ob mice, in association with reduced liver fat content, levels of transcripts related to neutral lipid synthesis and cholesterol were increased, suggesting "relief" of the secondary suppression imposed by lipid accumulation. Considering the fixed location of ILDR2 in the endoplasmic reticulum, we investigated the possible participation of ILDR2 in ER stress responses. In general, Ildr2 overexpression was associated with increases, and knockdown with decreases in levels of expression of molecular components of canonical ER stress pathways. We conclude that manipulation of Ildr2 expression in liver affects both lipid homeostasis and ER stress pathways. Given these reciprocal interactions, and the relatively extended time

  12. A physical/psychological and biological stress combine to enhance endoplasmic reticulum stress

    Energy Technology Data Exchange (ETDEWEB)

    Mondal, Tapan Kumar; Emeny, Rebecca T.; Gao, Donghong; Ault, Jeffrey G.; Kasten-Jolly, Jane; Lawrence, David A., E-mail: david.lawrence@health.ny.gov

    2015-12-01

    The generation of an immune response against infectious and other foreign agents is substantially modified by allostatic load, which is increased with chemical, physical and/or psychological stressors. The physical/psychological stress from cold-restraint (CR) inhibits host defense against Listeria monocytogenes (LM), due to early effects of the catecholamine norepinephrine (NE) from sympathetic nerves on β1-adrenoceptors (β1AR) of immune cells. Although CR activates innate immunity within 2 h, host defenses against bacterial growth are suppressed 2–3 days after infection (Cao and Lawrence 2002). CR enhances inducible nitric oxide synthase (iNOS) expression and NO production. The early innate activation leads to cellular reduction-oxidation (redox) changes of immune cells. Lymphocytes from CR-treated mice express fewer surface thiols. Splenic and hepatic immune cells also have fewer proteins with free thiols after CR and/or LM, and macrophages have less glutathione after the in vivo CR exposure or exposure to NE in vitro. The early induction of CR-induced oxidative stress elevates endoplasmic reticulum (ER) stress, which could interfere with keeping phagocytized LM within the phagosome or re-encapsuling LM by autophagy once they escape from the phagosome. ER stress-related proteins, such as glucose-regulated protein 78 (GRP78), have elevated expression with CR and LM. The results indicate that CR enhances the unfolded protein response (UPR), which interferes with host defenses against LM. Thus, it is postulated that increased stress, as exists with living conditions at low socioeconomic conditions, can lower host defenses against pathogens because of oxidative and ER stress processes. - Highlights: • Cold-restraint (physical/psychological stress) induces early oxidative stress. • The oxidative stress relates to catecholamine signaling beta-adrenoceptors. • Physical/psychological stress combines infection enhancing inflammation. • Endoplasmic reticulum

  13. Cardiac symptoms before sudden cardiac death caused by hypertrophic cardiomyopathy

    DEFF Research Database (Denmark)

    Lynge, Thomas Hadberg; Risgaard, Bjarke; Jabbari, Reza

    2016-01-01

    AIMS: Hypertrophic cardiomyopathy (HCM) is a frequent cause of sudden cardiac death (SCD) among the young (SCDY). The aim of this study was to characterize symptoms before SCDY due to HCM. METHODS AND RESULTS: Through review of all death certificates, we identified all SCDs in Danes aged 1-35 years...... in 2000-2009. Nationwide we included all deaths (n = 8756) and identified 431 autopsied SCDYs. All available records from hospitals and general practitioners were retrieved. To compare symptoms, we included a control groups consisting of traffic accident victims (n = 74). In the 10-year study period, 431...... autopsied SCDY cases were reviewed and 38 cases (9%) were included, of which 22 (58%) had morphologic findings diagnostic of HCM and 16 (42%) had findings suggestive, but not diagnostic, of HCM ('possible HCM'). Cardiac symptoms >1 h prior to death were reported in 21 (55%) of cases, and 16 (42%) sought...

  14. Boosters and barriers for direct cardiac reprogramming.

    Science.gov (United States)

    Talkhabi, Mahmood; Zonooz, Elmira Rezaei; Baharvand, Hossein

    2017-06-01

    Heart disease is currently the most significant cause of morbidity and mortality worldwide, which accounts for approximately 33% of all deaths. Recently, a promising and alchemy-like strategy has been developed called direct cardiac reprogramming, which directly converts somatic cells such as fibroblasts to cardiac lineage cells such as cardiomyocytes (CMs), termed induced CMs or iCMs. The first in vitro cardiac reprogramming study, mediated by cardiac transcription factors (TFs)-Gata4, Tbx5 and Mef2C-, was not enough efficient to produce an adequate number of fully reprogrammed, functional iCMs. As a result, numerous combinations of cardiac TFs exist for direct cardiac reprogramming of mouse and human fibroblasts. However, the efficiency of direct cardiac reprogramming remains low. Recently, a number of cellular and molecular mechanisms have been identified to increase the efficiency of direct cardiac reprogramming and the quality of iCMs. For example, microgrooved substrate, cardiogenic growth factors [VEGF, FGF, BMP4 and Activin A], and an appropriate stoichiometry of TFs boost the direct cardiac reprogramming. On the other hand, serum, TGFβ signaling, activators of epithelial to mesenchymal transition, and some epigenetic factors (Bmi1 and Ezh2) are barriers for direct cardiac reprogramming. Manipulating these mechanisms by the application of boosters and removing barriers can increase the efficiency of direct cardiac reprogramming and possibly make iCMs reliable for cell-based therapy or other potential applications. In this review, we summarize the latest trends in cardiac TF- or miRNA-based direct cardiac reprogramming and comprehensively discuses all molecular and cellular boosters and barriers affecting direct cardiac reprogramming. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Cardiac blood pool emission tomography

    International Nuclear Information System (INIS)

    Itti, R.; Philippe, L.; Lorgeron, J.M.; Charbonnier, B.; Raynaud, P.; Brochier, M.

    1983-01-01

    After blood pool labeling using technetium-99m, a series of cardiac pictures is acquired during the rotation of a gamma-camera about the patient. Computer processing leads to reconstruction of various tomographic slices from the original planar projection. Electrocardiographic gating selects the different phases of the cardiac cycle. Individual slices through the left ventricular region are added in order to provide ''thick'' slices on which global and regional parameters of the left ventricular function can be determined. Due to the proportionality existing between count rates and labeled blood volumes, any geometrical model can be avoided. The delineation of regions of interest for count integration is made easier due to the absence of superimposition of structures; no correction for background is necessary. Tomography thus appears to be more consistent and more accurate than the classical methods using planar projections. In addition, right ventricular morphological and kinetic studies can be performed in the same conditions as for the left ventricle [fr

  16. Respiratory gating in cardiac PET

    DEFF Research Database (Denmark)

    Lassen, Martin Lyngby; Rasmussen, Thomas; Christensen, Thomas E

    2017-01-01

    BACKGROUND: Respiratory motion due to breathing during cardiac positron emission tomography (PET) results in spatial blurring and erroneous tracer quantification. Respiratory gating might represent a solution by dividing the PET coincidence dataset into smaller respiratory phase subsets. The aim...... of our study was to compare the resulting imaging quality by the use of a time-based respiratory gating system in two groups administered either adenosine or dipyridamole as the pharmacological stress agent. METHODS AND RESULTS: Forty-eight patients were randomized to adenosine or dipyridamole cardiac...... stress (82)RB-PET. Respiratory rates and depths were measured by a respiratory gating system in addition to registering actual respiratory rates. Patients undergoing adenosine stress showed a decrease in measured respiratory rate from initial to later scan phase measurements [12.4 (±5.7) vs 5.6 (±4...

  17. The Danish Cardiac Rehabilitation Database

    DEFF Research Database (Denmark)

    Zwisler, Ann-Dorthe; Rossau, Henriette Knold; Nakano, Anne

    2016-01-01

    hospitals annually, with 75% receiving one or more outpatient rehabilitation services by 2015. The database has not yet been running for a full year, which explains the use of approximations. CONCLUSION: The DHRD is an online, national quality improvement database on CR, aimed at patients with CHD......AIM OF DATABASE: The Danish Cardiac Rehabilitation Database (DHRD) aims to improve the quality of cardiac rehabilitation (CR) to the benefit of patients with coronary heart disease (CHD). STUDY POPULATION: Hospitalized patients with CHD with stenosis on coronary angiography treated...... with percutaneous coronary intervention, coronary artery bypass grafting, or medication alone. Reporting is mandatory for all hospitals in Denmark delivering CR. The database was initially implemented in 2013 and was fully running from August 14, 2015, thus comprising data at a patient level from the latter date...

  18. Sudden cardiac death in athletes

    Directory of Open Access Journals (Sweden)

    Fábio Camilo Pellegrino dos Santos

    2012-11-01

    Full Text Available ABSTRACT The most accepted definition of sudden cardiac death nowadays is an unexplained death occurred suddenly within one hour of symptom onset. If it was not witnessed, individuals need to had been observed for at least 24 hours before the event and should be discarded the possibility of non cardiac causes of sudden death, pulmonary embolism or extensive malignancy. The term athlete refers to individuals of any age who participate in collective or individual regular physical activity, as well as physical training program for regular competitions. The sudden death of a young athlete, whether amateur or professional, especially during competitions, is always dramatic, with strong negative social impact and in the media. The fact that sports are recommended as a formula for longevity and quality of life makes these events a cause for concern in sports and society in general.

  19. Gene Therapy in Cardiac Arrhythmias

    OpenAIRE

    Praveen, S.V; Francis, Johnson; Venugopal, K

    2006-01-01

    Gene therapy has progressed from a dream to a bedside reality in quite a few human diseases. From its first application in adenosine deaminase deficiency, through the years, its application has evolved to vascular angiogenesis and cardiac arrhythmias. Gene based biological pacemakers using viral vectors or mesenchymal cells tested in animal models hold much promise. Induction of pacemaker activity within the left bundle branch can provide stable heart rates. Genetic modification of the AV...

  20. Cardiac surgery in the parturient.

    Science.gov (United States)

    Chandrasekhar, Shobana; Cook, Christopher R; Collard, Charles D

    2009-03-01

    Heart disease is the primary cause of nonobstetric mortality in pregnancy, occurring in 1%-3% of pregnancies and accounting for 10%-15% of maternal deaths. Congenital heart disease has become more prevalent in women of childbearing age, representing an increasing percentage (up to 75%) of heart disease in pregnancy. Untreated maternal heart disease also places the fetus at risk. Independent predictors of neonatal complications include a maternal New York Heart Association heart failure classification >2, anticoagulation use during pregnancy, smoking, multiple gestation, and left heart obstruction. Because cardiac surgical morbidity and mortality in the parturient is higher than nonpregnant patients, most parturients with cardiac disease are first managed medically, with cardiac surgery being reserved when medical management fails. Risk factors for maternal mortality during cardiac surgery include the use of vasoactive drugs, age, type of surgery, reoperation, and maternal functional class. Risk factors for fetal mortality include maternal age >35 yr, functional class, reoperation, emergency surgery, type of myocardial protection, and anoxic time. Nonetheless, acceptable maternal and fetal perioperative mortality rates may be achieved through such measures as early preoperative detection of maternal cardiovascular decompensation, use of fetal monitoring, delivery of a viable fetus before the operation and scheduling surgery on an elective basis during the second trimester. Additionally, fetal morbidity may be reduced during cardiopulmonary bypass by optimizing maternal oxygen-carrying capacity and uterine blood flow. Current maternal bypass recommendations include: 1) maintaining the pump flow rate >2.5 L x min(-1) x m(-2) and perfusion pressure >70 mm Hg; 2) maintaining the hematocrit > 28%; 3) using normothermic perfusion when feasible; 4) using pulsatile flow; and 5) using alpha-stat pH management.

  1. Cardiac rehabilitation: a comprehensive review

    OpenAIRE

    Lear, Scott A; Ignaszewski, Andrew

    2001-01-01

    Abstract Cardiac rehabilitation (CR) is a commonly used treatment for men and women with cardiovascular disease. To date, no single study has conclusively demonstrated a comprehensive benefit of CR. Numerous individual studies, however, have demonstrated beneficial effects such as improved risk-factor profile, slower disease progression, decreased morbidity, and decreased mortality. This paper will review the evidence for the use of CR and discuss the implications and limitations of these stu...

  2. The paediatrician and cardiac auscultation

    OpenAIRE

    Roy, Douglas L

    2003-01-01

    The cardiac auscultation (CA) skills of paediatric residents and office-based paediatricians have recently been shown to be suboptimal. CA is known to have a high degree of specificity and sensitivity, and is inexpensive. New teaching aids and availability of surrogate patient heart sounds and murmurs now allow most physicians to acquire CA skills. These teaching aids should be available in all medical schools and in all postgraduate paediatric training programs. While the relationship betwee...

  3. Clinical application of cardiac SPECT

    International Nuclear Information System (INIS)

    Nishimura, Shigeyuki

    1999-01-01

    Single-photon emission computed tomography (SPECT) has replaced planar imaging techniques for myocardial scintigraphy. Thallium-201 was the dominant agent employed for myocardial perfusion imaging. Today new technetium-99m labelled radionuclides have been used as excellent alternatives to 201 Tl for detection of coronary artery disease, prognostification, and even assessment of myocardial viability. Pharmacologic stress imaging using either dipyridamole, adenosine or dobutamine is a substitute for exercise stress. Accurate determination of myocardial viability is vitally important for clinical decision making for patients with LV dysfunction who will most benefit from revascularization. Stunned and hibernated myocardium may result in profound regional LTV dysfunction in absence of necrosis. The various approach such as stress-redistribution-reinjection imaging, rest-redistribution imaging and stress-redistribution-24 hours delayed imaging has been utilized to assess myocardial viability with 201 Tl. Quantitative assessment of 99m Tc MIBI uptake reflect the degree of viability. 123 I-Metaiodobenzylguanidine (MIBG), an analog of norepinephrine, has been used for scintigraphic assessment of regional cardiac adrenergic innervation. Cardiac sympathetic denervation, assessed by 123 I-MIBG, due to ischemia in non-Q myocardial infarction and unstable angina has been shown. Quantitative cardiac MIBG scintigram was shown to have prognostic value in patients with severe congestive heart failure. 23 I-BMIPP (ρ-methyl-iodophenyl pentadecanoic acid) has been used to assess myocardial fatty acid utilization. BMIPP has the memory function of ischemia in unstable angina, since decreased BMIPP uptake persists several days after ischemic episode. Nuclear cardiology in Japan has experienced an expansion in the techniques including use of new radionuclides, 99m Tc perfusion agents, 123 I-MIBG and 23 I-BMIPP and in associated clinical application to the various cardiac diseases

  4. Sarcoplasmatic and myofibrillar protein changes caused by acute heat stress in broiler chicken Alterações nas proteínas sarcoplasmáticas e miofibrilares em frangos de corte causadas por estresse térmico agudo

    Directory of Open Access Journals (Sweden)

    Carolina de Castro Santos

    2008-01-01

    Full Text Available Acute heat stress (AHS modifies the structure of myofibrils affecting functional properties of meat, mainly the water holding capacity. This experiment aimed to identify changes in proteolysis and migration between the myofibrillar and sarcoplasmatic fractions due to pre-slaughter AHS. Myofibrillar fragmentation index (MFI, SDS-PAGE, western blot of vinculin (WB and shear force (SF were determined. Six hundred broilers (Gallus gallus were slaughtered in three different days (ST. In each ST, groups of ten animals were placed in transport crates and submitted to AHS (35ºC, 75 - 85% RH for 2 hours. Simultaneously, the non-stressed broilers (NS were kept in thermoneutral environment (22ºC, 83 ± 6.6% RH within the crates in the same density. After slaughter, the breast muscles were kept refrigerated until the withdrawal of all samples (0, 1, 2, 6 and 24 hours after slaughter. Sampling within AHS and NS birds was collected according to lightness value (normal L* 51, except for determination of MFI and SF. The lightness was used later to perform SDS-PAGE and WB analyses. MFI kinetics showed that the fragmentation rate was superior in animals NS, indicating that AHS can harm proteolysis and rate of myofibrillar fragmentation. However, the extent of fragmentation did not change, as well as SF values. SDS-PAGE for Troponin fragments indicated a differentiated pattern between AHS and NS. The WB did not show alterations in vinculin fragmentation. Modifications in sarcoplasmatic fraction are observed in meat with high L*values, independent of environmental condition.O estresse térmico agudo (ET causa alterações na estrutura das miofibrilas, afetando propriedades funcionais da carne, principalmente a capacidade de retenção de água. Identificaram-se mudanças na proteólise e migração entre as frações miofibrilar e sarcoplasmática, decorrentes do ET pré-abate, através do índice de fragmentação miofibrilar (MFI, SDS-PAGE para troponina (SDS

  5. Pregnancy as a cardiac stress model

    Science.gov (United States)

    Chung, Eunhee; Leinwand, Leslie A.

    2014-01-01

    Cardiac hypertrophy occurs during pregnancy as a consequence of both volume overload and hormonal changes. Both pregnancy- and exercise-induced cardiac hypertrophy are generally thought to be similar and physiological. Despite the fact that there are shared transcriptional responses in both forms of cardiac adaptation, pregnancy results in a distinct signature of gene expression in the heart. In some cases, however, pregnancy can induce adverse cardiac events in previously healthy women without any known cardiovascular disease. Peripartum cardiomyopathy is the leading cause of non-obstetric mortality during pregnancy. To understand how pregnancy can cause heart disease, it is first important to understand cardiac adaptation during normal pregnancy. This review provides an overview of the cardiac consequences of pregnancy, including haemodynamic, functional, structural, and morphological adaptations, as well as molecular phenotypes. In addition, this review describes the signalling pathways responsible for pregnancy-induced cardiac hypertrophy and angiogenesis. We also compare and contrast cardiac adaptation in response to disease, exercise, and pregnancy. The comparisons of these settings of cardiac hypertrophy provide insight into pregnancy-associated cardiac adaptation. PMID:24448313

  6. Cardiac MRI in restrictive cardiomyopathy

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, A. [Department of Cardiovascular Radiology, All India Institute of Medical Sciences, Ansari Nagar, Delhi (India); Singh Gulati, G., E-mail: gulatigurpreet@rediffmail.com [Department of Cardiovascular Radiology, All India Institute of Medical Sciences, Ansari Nagar, Delhi (India); Seth, S. [Department of Cardiology, All India Institute of Medical Sciences, Ansari Nagar, Delhi (India); Sharma, S. [Department of Cardiovascular Radiology, All India Institute of Medical Sciences, Ansari Nagar, Delhi (India)

    2012-02-15

    Restrictive cardiomyopathy (RCM) is a specific group of heart muscle disorders characterized by inadequate ventricular relaxation during diastole. This leads to diastolic dysfunction with relative preservation of systolic function. Although short axis systolic function is usually preserved in RCM, the long axis systolic function may be severely impaired. Confirmation of diagnosis and information regarding aetiology, extent of myocardial damage, and response to treatment requires imaging. Importantly, differentiation from constrictive pericarditis (CCP) is needed, as only the latter is managed surgically. Echocardiography is the initial cardiac imaging technique but cannot reliably suggest a tissue diagnosis; although recent advances, especially tissue Doppler imaging and spectral tracking, have improved its ability to differentiate RCM from CCP. Cardiac catheterization is the reference standard, but is invasive, two-dimensional, and does not aid myocardial characterization. Cardiac magnetic resonance (CMR) is a versatile technique providing anatomical, morphological and functional information. In recent years, it has been shown to provide important information regarding disease mechanisms, and also been found useful to guide treatment, assess its outcome and predict patient prognosis. This review describes the CMR features of RCM, appearances in various diseases, its overall role in patient management, and how it compares with other imaging techniques.

  7. Type 2 diabetes mellitus induces congenital heart defects in murine embryos by increasing oxidative stress, endoplasmic reticulum stress, and apoptosis.

    Science.gov (United States)

    Wu, Yanqing; Reece, E Albert; Zhong, Jianxiang; Dong, Daoyin; Shen, Wei-Bin; Harman, Christopher R; Yang, Peixin

    2016-09-01

    Maternal type 1 and 2 diabetes mellitus are strongly associated with high rates of severe structural birth defects, including congenital heart defects. Studies in type 1 diabetic embryopathy animal models have demonstrated that cellular stress-induced apoptosis mediates the teratogenicity of maternal diabetes leading to congenital heart defect formation. However, the mechanisms underlying maternal type 2 diabetes mellitus-induced congenital heart defects remain largely unknown. We aim to determine whether oxidative stress, endoplasmic reticulum stress, and excessive apoptosis are the intracellular molecular mechanisms underlying maternal type 2 diabetes mellitus-induced congenital heart defects. A mouse model of maternal type 2 diabetes mellitus was established by feeding female mice a high-fat diet (60% fat). After 15 weeks on the high-fat diet, the mice showed characteristics of maternal type 2 diabetes mellitus. Control dams were either fed a normal diet (10% fat) or the high-fat diet during pregnancy only. Female mice from the high-fat diet group and the 2 control groups were mated with male mice that were fed a normal diet. At E12.5, embryonic hearts were harvested to determine the levels of lipid peroxides and superoxide, endoplasmic reticulum stress markers, cleaved caspase 3 and 8, and apoptosis. E17.5 embryonic hearts were harvested for the detection of congenital heart defect formation using India ink vessel patterning and histological examination. Maternal type 2 diabetes mellitus significantly induced ventricular septal defects and persistent truncus arteriosus in the developing heart, along with increasing oxidative stress markers, including superoxide and lipid peroxidation; endoplasmic reticulum stress markers, including protein levels of phosphorylated-protein kinase RNA-like endoplasmic reticulum kinase, phosphorylated-IRE1α, phosphorylated-eIF2α, C/EBP homologous protein, and binding immunoglobulin protein; endoplasmic reticulum chaperone gene

  8. Cardiac tamponade: contrast reflux as an indicator of cardiac chamber equalization

    Directory of Open Access Journals (Sweden)

    Nauta Foeke Jacob

    2012-05-01

    Full Text Available Abstract Background Traumatic hemopericardium remains a rare entity; it does however commonly cause cardiac tamponade which remains a major cause of death in traumatic blunt cardiac injury. Objectives We present a case of blunt chest trauma complicated by cardiac tamponade causing cardiac chamber equalization revealed by reflux of contrast. Case report A 29-year-old unidentified male suffered blunt chest trauma in a motor vehicle collision. Computed tomography (CT demonstrated a periaortic hematoma and hemopericardium. Significant contrast reflux was seen in the inferior vena cava and hepatic veins suggesting a change in cardiac chamber pressures. After intensive treatment including cardiac massage this patient expired of cardiac arrest. Conclusion Reflux of contrast on CT imaging can be an indicator of traumatic cardiac tamponade.

  9. Fluoride-elicited developmental testicular toxicity in rats: Roles of endoplasmic reticulum stress and inflammatory response

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shun [Department of Environmental Health and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan 430030, Hubei (China); Jiang, Chunyang [Department of Environmental Health and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan 430030, Hubei (China); Department of Thoracic Surgery, Tianjin Union Medicine Centre, 190 Jieyuan Road, Hongqiao District, Tianjin 300121, Tianjin (China); Liu, Hongliang [Tianjin Center for Disease Control and Prevention, Huayue Road 6, Hedong Region, Tianjin 300011, Tianjin (China); Guan, Zhizhong [Department of Pathology, Guiyang Medical College, Guiyang 550004, Guizhou (China); Zeng, Qiang [Tianjin Center for Disease Control and Prevention, Huayue Road 6, Hedong Region, Tianjin 300011, Tianjin (China); Zhang, Cheng; Lei, Rongrong; Xia, Tao; Gao, Hui; Yang, Lu; Chen, Yihu; Wu, Xue; Zhang, Xiaofei [Department of Environmental Health and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan 430030, Hubei (China); Cui, Yushan; Yu, Linyu [Tianjin Center for Disease Control and Prevention, Huayue Road 6, Hedong Region, Tianjin 300011, Tianjin (China); Wang, Zhenglun [Department of Environmental Health and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan 430030, Hubei (China); Wang, Aiguo, E-mail: wangaiguo@mails.tjmu.edu.cn [Department of Environmental Health and MOE Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan 430030, Hubei (China)

    2013-09-01

    Long-term excessive fluoride intake is known to be toxic and can damage a variety of organs and tissues in the human body. However, the molecular mechanisms underlying fluoride-induced male reproductive toxicity are not well understood. In this study, we used a rat model to simulate the situations of human exposure and aimed to evaluate the roles of endoplasmic reticulum (ER) stress and inflammatory response in fluoride-induced testicular injury. Sprague–Dawley rats were administered with sodium fluoride (NaF) at 25, 50 and 100 mg/L via drinking water from pre-pregnancy to gestation, birth and finally to post-puberty. And then the testes of male offspring were studied at 8 weeks of age. Our results demonstrated that fluoride treatment increased MDA accumulation, decreased SOD activity, and enhanced germ cell apoptosis. In addition, fluoride elevated mRNA and protein levels of glucose-regulated protein 78 (GRP78), inositol requiring ER-to-nucleus signal kinase 1 (IRE1), and C/EBP homologous protein (CHOP), indicating activation of ER stress signaling. Furthermore, fluoride also induced testicular inflammation, as manifested by gene up-regulation of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), in a nuclear factor-κB (NF-κB)-dependent manner. These were associated with marked histopathological lesions including injury of spermatogonia, decrease of spermatocytes and absence of elongated spermatids, as well as severe ultrastructural abnormalities in testes. Taken together, our results provide compelling evidence that ER stress and inflammation would be novel and significant mechanisms responsible for fluoride-induced disturbance of spermatogenesis and germ cell loss in addition to oxidative stress. - Highlights: • We used a rat model to simulate the situations of human fluoride (F) exposure. • Developmental F exposure induces testicular damage related with oxidative stress.

  10. Prodigiosin activates endoplasmic reticulum stress cell death pathway in human breast carcinoma cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Mu-Yun [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Shen, Yuh-Chiang [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); National Research Institute of Chinese Medicine, Taipei, Taiwan (China); Lu, Chien-Hsing [Department of Obstetrics and Gynecology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Department of Obstetrics and Gynecology, National Yang-Ming University School of Medicine, Taipei, Taiwan (China); Yang, Shu-Yi [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Ho, Tsing-Fen [Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan (China); Peng, Yu-Ta [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Chang, Chia-Che, E-mail: chia_che@dragon.nchu.edu.tw [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan (China); Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan (China)

    2012-12-15

    Prodigiosin is a bacterial tripyrrole pigment with potent cytotoxicity against diverse human cancer cell lines. Endoplasmic reticulum (ER) stress is initiated by accumulation of unfolded or misfolded proteins in the ER lumen and may induce cell death when irremediable. In this study, the role of ER stress in prodigiosin-induced cytotoxicity was elucidated for the first time. Comparable to the ER stress inducer thapsigargin, prodigiosin up-regulated signature ER stress markers GRP78 and CHOP in addition to activating the IRE1, PERK and ATF6 branches of the unfolded protein response (UPR) in multiple human breast carcinoma cell lines, confirming prodigiosin as an ER stress inducer. Prodigiosin transcriptionally up-regulated CHOP, as evidenced by its promoting effect on the CHOP promoter activity. Of note, knockdown of CHOP effectively lowered prodigiosin's capacity to evoke PARP cleavage, reduce cell viability and suppress colony formation, highlighting an essential role of CHOP in prodigiosin-induced cytotoxic ER stress response. In addition, prodigiosin down-regulated BCL2 in a CHOP-dependent manner. Importantly, restoration of BCL2 expression blocked prodigiosin-induced PARP cleavage and greatly enhanced the survival of prodigiosin-treated cells, suggesting that CHOP-dependent BCL2 suppression mediates prodigiosin-elicited cell death. Moreover, pharmacological inhibition of JNK by SP600125 or dominant-negative blockade of PERK-mediated eIF2α phosphorylation impaired prodigiosin-induced CHOP up-regulation and PARP cleavage. Collectively, these results identified ER stress-mediated cell death as a mode-of-action of prodigiosin's tumoricidal effect. Mechanistically, prodigiosin engages the IRE1–JNK and PERK–eIF2α branches of the UPR signaling to up-regulate CHOP, which in turn mediates BCL2 suppression to induce cell death. Highlights: ► Prodigiosin is a bacterial tripyrrole pigment with potent anticancer effect. ► Prodigiosin is herein identified

  11. The role of cholesterol in the association of endoplasmic reticulum membranes with mitochondria

    International Nuclear Information System (INIS)

    Fujimoto, Michiko; Hayashi, Teruo; Su, Tsung-Ping

    2012-01-01

    Highlights: ► The endoplasmic reticulum subdomain termed MAM associates with mitochondria. ► The biophysical role of lipids in the MAM–mitochondria association is unknown. ► The in vitro membrane association assay was used to examine the role of lipids. ► Cholesterol was found to negatively regulate the association. -- Abstract: The unique endoplasmic reticulum (ER) subdomain termed the mitochondria-associated ER membrane (MAM) engages the physical connection between the ER and the mitochondrial outer membrane and plays a role in regulating IP 3 receptor-mediated Ca 2+ influx and the phospholipid transport between the two organelles. The MAM contains certain signaling and membrane-tethering proteins but also lipids including cholesterol. The biophysical role of lipids at the MAM, specifically in the physical interaction between the MAM of the ER and mitochondria, remains not totally clarified. Here we employed the in vitro membrane association assay to investigate the role of cholesterol in the association between MAMs and mitochondria. The purified MAMs and mitochondria were mixed in vitro in a test tube and then the physical association of the two subcellular organelles was quantified indirectly by measuring the presence of the MAM-specific protein sigma-1 receptors in the mitochondria fraction. Purified MAMs contained free cholesterol approximately 7 times higher than that in microsomes. We found that depletion of cholesterol in MAMs with methyl-β-cyclodextrin (MβC) significantly increases the association between MAMs and mitochondria, whereas MβC saturated with cholesterol does not change the association. 14 C-Serine pulse-labeling demonstrated that the treatment of living cells with MβC decreases the level of de novo synthesized 14 C-phosphatidylserine (PtSer) and concomitantly increases greatly the synthesis of 14 C-phosphatidylethanolamine (PtEt). Apparently, cholesterol depletion increased the PtSer transport from MAMs to mitochondria. Our

  12. The role of cholesterol in the association of endoplasmic reticulum membranes with mitochondria

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, Michiko [Cellular Stress Signaling Unit, Integrative Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, MD 21224 (United States); Hayashi, Teruo, E-mail: thayashi@mail.nih.gov [Cellular Stress Signaling Unit, Integrative Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, MD 21224 (United States); Su, Tsung-Ping, E-mail: tsu@intra.nida.nih.gov [Cellular Pathobiology Section, Integrative Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, MD 21224 (United States)

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer The endoplasmic reticulum subdomain termed MAM associates with mitochondria. Black-Right-Pointing-Pointer The biophysical role of lipids in the MAM-mitochondria association is unknown. Black-Right-Pointing-Pointer The in vitro membrane association assay was used to examine the role of lipids. Black-Right-Pointing-Pointer Cholesterol was found to negatively regulate the association. -- Abstract: The unique endoplasmic reticulum (ER) subdomain termed the mitochondria-associated ER membrane (MAM) engages the physical connection between the ER and the mitochondrial outer membrane and plays a role in regulating IP{sub 3} receptor-mediated Ca{sup 2+} influx and the phospholipid transport between the two organelles. The MAM contains certain signaling and membrane-tethering proteins but also lipids including cholesterol. The biophysical role of lipids at the MAM, specifically in the physical interaction between the MAM of the ER and mitochondria, remains not totally clarified. Here we employed the in vitro membrane association assay to investigate the role of cholesterol in the association between MAMs and mitochondria. The purified MAMs and mitochondria were mixed in vitro in a test tube and then the physical association of the two subcellular organelles was quantified indirectly by measuring the presence of the MAM-specific protein sigma-1 receptors in the mitochondria fraction. Purified MAMs contained free cholesterol approximately 7 times higher than that in microsomes. We found that depletion of cholesterol in MAMs with methyl-{beta}-cyclodextrin (M{beta}C) significantly increases the association between MAMs and mitochondria, whereas M{beta}C saturated with cholesterol does not change the association. {sup 14}C-Serine pulse-labeling demonstrated that the treatment of living cells with M{beta}C decreases the level of de novo synthesized {sup 14}C-phosphatidylserine (PtSer) and concomitantly increases greatly the synthesis of

  13. Prodigiosin activates endoplasmic reticulum stress cell death pathway in human breast carcinoma cell lines

    International Nuclear Information System (INIS)

    Pan, Mu-Yun; Shen, Yuh-Chiang; Lu, Chien-Hsing; Yang, Shu-Yi; Ho, Tsing-Fen; Peng, Yu-Ta; Chang, Chia-Che

    2012-01-01

    Prodigiosin is a bacterial tripyrrole pigment with potent cytotoxicity against diverse human cancer cell lines. Endoplasmic reticulum (ER) stress is initiated by accumulation of unfolded or misfolded proteins in the ER lumen and may induce cell death when irremediable. In this study, the role of ER stress in prodigiosin-induced cytotoxicity was elucidated for the first time. Comparable to the ER stress inducer thapsigargin, prodigiosin up-regulated signature ER stress markers GRP78 and CHOP in addition to activating the IRE1, PERK and ATF6 branches of the unfolded protein response (UPR) in multiple human breast carcinoma cell lines, confirming prodigiosin as an ER stress inducer. Prodigiosin transcriptionally up-regulated CHOP, as evidenced by its promoting effect on the CHOP promoter activity. Of note, knockdown of CHOP effectively lowered prodigiosin's capacity to evoke PARP cleavage, reduce cell viability and suppress colony formation, highlighting an essential role of CHOP in prodigiosin-induced cytotoxic ER stress response. In addition, prodigiosin down-regulated BCL2 in a CHOP-dependent manner. Importantly, restoration of BCL2 expression blocked prodigiosin-induced PARP cleavage and greatly enhanced the survival of prodigiosin-treated cells, suggesting that CHOP-dependent BCL2 suppression mediates prodigiosin-elicited cell death. Moreover, pharmacological inhibition of JNK by SP600125 or dominant-negative blockade of PERK-mediated eIF2α phosphorylation impaired prodigiosin-induced CHOP up-regulation and PARP cleavage. Collectively, these results identified ER stress-mediated cell death as a mode-of-action of prodigiosin's tumoricidal effect. Mechanistically, prodigiosin engages the IRE1–JNK and PERK–eIF2α branches of the UPR signaling to up-regulate CHOP, which in turn mediates BCL2 suppression to induce cell death. Highlights: ► Prodigiosin is a bacterial tripyrrole pigment with potent anticancer effect. ► Prodigiosin is herein identified as an

  14. Nucleocapsid Protein from Fig Mosaic Virus Forms Cytoplasmic Agglomerates That Are Hauled by Endoplasmic Reticulum Streaming

    Science.gov (United States)

    Ishikawa, Kazuya; Miura, Chihiro; Maejima, Kensaku; Komatsu, Ken; Hashimoto, Masayoshi; Tomomitsu, Tatsuya; Fukuoka, Misato; Yusa, Akira; Yamaji, Yasuyuki

    2014-01-01

    ABSTRACT Although many studies have demonstrated intracellular movement of viral proteins or viral replication complexes, little is known about the mechanisms of their motility. In this study, we analyzed the localization and motility of the nucleocapsid protein (NP) of Fig mosaic virus (FMV), a negative-strand RNA virus belonging to the recently established genus Emaravirus. Electron microscopy of FMV-infected cells using immunogold labeling showed that NPs formed cytoplasmic agglomerates that were predominantly enveloped by the endoplasmic reticulum (ER) membrane, while nonenveloped NP agglomerates also localized along the ER. Likewise, transiently expressed NPs formed agglomerates, designated NP bodies (NBs), in close proximity to the ER, as was the case in FMV-infected cells. Subcellular fractionation and electron microscopic analyses of NP-expressing cells revealed that NBs localized in the cytoplasm. Furthermore, we found that NBs moved rapidly with the streaming of the ER in an actomyosin-dependent manner. Brefeldin A treatment at a high concentration to disturb the ER network configuration induced aberrant accumulation of NBs in the perinuclear region, indicating that the ER network configuration is related to NB localization. Dominant negative inhibition of the class XI myosins, XI-1, XI-2, and XI-K, affected both ER streaming and NB movement in a similar pattern. Taken together, these results showed that NBs localize in the cytoplasm but in close proximity to the ER membrane to form enveloped particles and that this causes passive movements of cytoplasmic NBs by ER streaming. IMPORTANCE Intracellular trafficking is a primary and essential step for the cell-to-cell movement of viruses. To date, many studies have demonstrated the rapid intracellular movement of viral factors but have failed to provide evidence for the mechanism or biological significance of this motility. Here, we observed that agglomerates of nucleocapsid protein (NP) moved rapidly

  15. Fluoride-elicited developmental testicular toxicity in rats: Roles of endoplasmic reticulum stress and inflammatory response

    International Nuclear Information System (INIS)

    Zhang, Shun; Jiang, Chunyang; Liu, Hongliang; Guan, Zhizhong; Zeng, Qiang; Zhang, Cheng; Lei, Rongrong; Xia, Tao; Gao, Hui; Yang, Lu; Chen, Yihu; Wu, Xue; Zhang, Xiaofei; Cui, Yushan; Yu, Linyu; Wang, Zhenglun; Wang, Aiguo

    2013-01-01

    Long-term excessive fluoride intake is known to be toxic and can damage a variety of organs and tissues in the human body. However, the molecular mechanisms underlying fluoride-induced male reproductive toxicity are not well understood. In this study, we used a rat model to simulate the situations of human exposure and aimed to evaluate the roles of endoplasmic reticulum (ER) stress and inflammatory response in fluoride-induced testicular injury. Sprague–Dawley rats were administered with sodium fluoride (NaF) at 25, 50 and 100 mg/L via drinking water from pre-pregnancy to gestation, birth and finally to post-puberty. And then the testes of male offspring were studied at 8 weeks of age. Our results demonstrated that fluoride treatment increased MDA accumulation, decreased SOD activity, and enhanced germ cell apoptosis. In addition, fluoride elevated mRNA and protein levels of glucose-regulated protein 78 (GRP78), inositol requiring ER-to-nucleus signal kinase 1 (IRE1), and C/EBP homologous protein (CHOP), indicating activation of ER stress signaling. Furthermore, fluoride also induced testicular inflammation, as manifested by gene up-regulation of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), in a nuclear factor-κB (NF-κB)-dependent manner. These were associated with marked histopathological lesions including injury of spermatogonia, decrease of spermatocytes and absence of elongated spermatids, as well as severe ultrastructural abnormalities in testes. Taken together, our results provide compelling evidence that ER stress and inflammation would be novel and significant mechanisms responsible for fluoride-induced disturbance of spermatogenesis and germ cell loss in addition to oxidative stress. - Highlights: • We used a rat model to simulate the situations of human fluoride (F) exposure. • Developmental F exposure induces testicular damage related with oxidative stress.

  16. Up-regulation of mRNA ventricular PRNP prion protein gene expression in air pollution highly exposed young urbanites: endoplasmic reticulum stress, glucose regulated protein 78, and nanosized particles.

    Science.gov (United States)

    Villarreal-Calderon, Rodolfo; Franco-Lira, Maricela; González-Maciel, Angélica; Reynoso-Robles, Rafael; Harritt, Lou; Pérez-Guillé, Beatriz; Ferreira-Azevedo, Lara; Drecktrah, Dan; Zhu, Hongtu; Sun, Qiang; Torres-Jardón, Ricardo; Aragón-Flores, Mariana; Calderón-Garcidueñas, Ana; Diaz, Philippe; Calderón-Garcidueñas, Lilian

    2013-11-28

    Mexico City Metropolitan Area children and young adults exposed to high concentrations of air pollutants including fine and ultrafine particulate matter (PM) vs. clean air controls, exhibit myocardial inflammation and inflammasome activation with a differential right and left ventricular expression of key inflammatory genes and inflammasomes. We investigated the mRNA expression levels of the prion protein gene PRNP, which plays an important role in the protection against oxidative stress and metal toxicity, and the glucose regulated protein 78, a key protein in endoplasmic reticulum (ER) stress signaling, in ventricular autopsy samples from 30 children and young adults age 19.97 ± 6.8 years with a lifetime of low (n:4) vs. high (n:26) air pollution exposures. Light microscopy and transmission electron microscopy studies were carried out in human ventricles, and electron microscopy studies were also done in 5 young, highly exposed Mexico City dogs. There was significant left ventricular PRNP and bi-ventricular GRP78 mRNA up-regulation in Mexico City young urbanites vs. controls. PRNP up-regulation in the left ventricle was significantly different from the right, p < 0.0001, and there was a strong left ventricular PRNP and GRP78 correlation (p = 0.0005). Marked abnormalities in capillary endothelial cells, numerous nanosized particles in myocardial ER and in abnormal mitochondria characterized the highly exposed ventricles. Early and sustained cardiac ER stress could result in detrimental irreversible consequences in urban children, and while highly complex systems maintain myocardial homeostasis, failure to compensate for chronic myocardial inflammation, oxidative and ER stress, and particles damaging myocardial organelles may prime the development of pathophysiological cardiovascular states in young urbanites. Nanosized PM could play a key cardiac myocyte toxicity role.

  17. Diallyl trisulfide ameliorates myocardial ischemia-reperfusion injury by reducing oxidative stress and endoplasmic reticulum stress-mediated apoptosis in type 1 diabetic rats: role of SIRT1 activation.

    Science.gov (United States)

    Yu, Liming; Li, Shu; Tang, Xinlong; Li, Zhi; Zhang, Jian; Xue, Xiaodong; Han, Jinsong; Liu, Yu; Zhang, Yuji; Zhang, Yong; Xu, Yinli; Yang, Yang; Wang, Huishan

    2017-07-01

    Diallyl trisulfide (DATS) protects against apoptosis during myocardial ischemia-reperfusion (MI/R) injury in diabetic state, although the underlying mechanisms remain poorly defined. Previously, we and others demonstrated that silent information regulator 1 (SIRT1) activation inhibited oxidative stress and endoplasmic reticulum (ER) stress during MI/R injury. We hypothesize that DATS reduces diabetic MI/R injury by activating SIRT1 signaling. Streptozotocin (STZ)-induced type 1 diabetic rats were subjected to MI/R surgery with or without perioperative administration of DATS (40 mg/kg). We found that DATS treatment markedly improved left ventricular systolic pressure and the first derivative of left ventricular pressure, reduced myocardial infarct size as well as serum creatine kinase and lactate dehydrogenase activities. Furthermore, the myocardial apoptosis was also suppressed by DATS as evidenced by reduced apoptotic index and cleaved caspase-3 expression. However, these effects were abolished by EX527 (the inhibitor of SIRT1 signaling, 5 mg/kg). We further found that DATS effectively upregulated SIRT1 expression and its nuclear distribution. Additionally, PERK/eIF2α/ATF4/CHOP-mediated ER stress-induced apoptosis was suppressed by DATS treatment. Moreover, DATS significantly activated Nrf-2/HO-1 antioxidant signaling pathway, thus reducing Nox-2/4 expressions. However, the ameliorative effects of DATS on oxidative stress and ER stress-mediated myocardial apoptosis were inhibited by EX527 administration. Taken together, these data suggest that perioperative DATS treatment effectively ameliorates MI/R injury in type 1 diabetic setting by enhancing cardiac SIRT1 signaling. SIRT1 activation not only upregulated Nrf-2/HO-1-mediated antioxidant signaling pathway but also suppressed PERK/eIF2α/ATF4/CHOP-mediated ER stress level, thus reducing myocardial apoptosis and eventually preserving cardiac function.

  18. Up-Regulation of mRNA Ventricular PRNP Prion Protein Gene Expression in Air Pollution Highly Exposed Young Urbanites: Endoplasmic Reticulum Stress, Glucose Regulated Protein 78, and Nanosized Particles

    Directory of Open Access Journals (Sweden)

    Rodolfo Villarreal-Calderon

    2013-11-01

    Full Text Available Mexico City Metropolitan Area children and young adults exposed to high concentrations of air pollutants including fine and ultrafine particulate matter (PM vs. clean air controls, exhibit myocardial inflammation and inflammasome activation with a differential right and left ventricular expression of key inflammatory genes and inflammasomes. We investigated the mRNA expression levels of the prion protein gene PRNP, which plays an important role in the protection against oxidative stress and metal toxicity, and the glucose regulated protein 78, a key protein in endoplasmic reticulum (ER stress signaling, in ventricular autopsy samples from 30 children and young adults age 19.97 ± 6.8 years with a lifetime of low (n:4 vs. high (n:26 air pollution exposures. Light microscopy and transmission electron microscopy studies were carried out in human ventricles, and electron microscopy studies were also done in 5 young, highly exposed Mexico City dogs. There was significant left ventricular PRNP and bi-ventricular GRP78 mRNA up-regulation in Mexico City young urbanites vs. controls. PRNP up-regulation in the left ventricle was significantly different from the right, p < 0.0001, and there was a strong left ventricular PRNP and GRP78 correlation (p = 0.0005. Marked abnormalities in capillary endothelial cells, numerous nanosized particles in myocardial ER and in abnormal mitochondria characterized the highly exposed ventricles. Early and sustained cardiac ER stress could result in detrimental irreversible consequences in urban children, and while highly complex systems maintain myocardial homeostasis, failure to compensate for chronic myocardial inflammation, oxidative and ER stress, and particles damaging myocardial organelles may prime the development of pathophysiological cardiovascular states in young urbanites. Nanosized PM could play a key cardiac myocyte toxicity role.

  19. Protein-accumulating cells and dilated cisternae of the endoplasmic reticulum in three glucosinolate-containing genera: Armoracia, Capparis, Drypetes.

    Science.gov (United States)

    Jørgensen, L B; Behnke, H D; Mabry, T J

    1977-01-01

    Three glucosinolate-containing species, Armoracia rusticana Gaertner, Meyer et Scherbius (Brassicaceae), Capparis cynophallophora L. (Capparaceae) and Drypetes roxburghii (Wall.) Hurusawa (Euphorbiaceae), are shown by both light and electron microscopy to contain protein-accumulating cells (PAC). The PAC of Armoracia and Copparis (former "myrosin cells") occur as idioblasts. The PAC of Drypetes are usual members among axial phloem parenchyma cells rather than idioblasts. In Drypetes the vacuoles of the PAC are shown ultrastructurally to contain finely fibrillar material and to originate from local dilatations of the endoplasmic reticulum. The vacuoles in PAC of Armoracia and Capparis seem to originate in the same way; but ultrastructurally, their content is finely granular. In addition, Armoracia and Capparis are shown by both light and electron microscopy to contain dilated cisternae (DC) of the endoplasmic reticulum in normal parenchyma cells, in accord with previous findings for several species within Brassicaceae. The relationship of PAC and DC to glucosinolates and the enzyme myrosinase is discussed.

  20. Quantification of plasmodesmatal endoplasmic reticulum coupling between sieve elements and companion cells using fluorescence redistribution after photobleaching

    DEFF Research Database (Denmark)

    Martens, Helle; Roberts, Alison G.; Oparka, Karl J.

    2006-01-01

    retrieval along the pathway is an integral component of phloem function. GFP fluorescence was limited to CCs where it was visualized as a well-developed ER network in close proximity to the plasma membrane. ER coupling between CC and SEs was tested in wild-type tobacco using an ER-specific fluorochrome......Transgenic tobacco (Nicotiana tabacum) was studied to localize the activity of phloem loading during development and to establish whether the endoplasmic reticulum (ER) of the companion cell (CC) and the sieve element (SE) reticulum is continuous by using a SUC2 promoter-green fluorescent protein...... and fluorescence redistribution after photobleaching (FRAP), and showed that the ER is continuous via pore-plasmodesma units. ER coupling between CC and SE was quantified by determining the mobile fraction and half-life of fluorescence redistribution and compared with that of other cell types. In all tissues...

  1. Effect of endoplasmic reticulum stress on the response of HeLa cells to carbon ion radiation

    International Nuclear Information System (INIS)

    Xia Jiefang; Wang Zhuanzi; Wei Wei; Dang Bingrong; Li Wenjian

    2015-01-01

    To investigate the effect of endoplasmic reticulum stress on HeLa cells to "1"2C"6"+ ion irradiation, HeLa cells were pretreated with 2.5 mmol/L dithiothreitol and irradiated by "1"2C"6"+ ions with different doses. The results showed that, compared with IR alone, dithiothreitol combined with carbon ion irradiation caused HeLa cell survival decreased, and the apoptosis increased. Moreover, dithiothreitol and carbon ion radiation combination treatment led to a significant increase of G_2/M phase, and autophagy was activated obviously in combination treatment group. The results imply that continuous endoplasmic reticulum stress can change the response of HeLa cells to "1"2C"6"+ irradiation, and dithiothreitol may affect HeLa cells through the autophagy cell death pathway. (authors)

  2. Glucosamine-induced endoplasmic reticulum stress affects GLUT4 expression via activating transcription factor 6 in rat and human skeletal muscle cells

    DEFF Research Database (Denmark)

    Raciti, G A; Iadicicco, C; Ulianich, L

    2010-01-01

    Glucosamine, generated during hyperglycaemia, causes insulin resistance in different cells. Here we sought to evaluate the possible role of endoplasmic reticulum (ER) stress in the induction of insulin resistance by glucosamine in skeletal muscle cells.......Glucosamine, generated during hyperglycaemia, causes insulin resistance in different cells. Here we sought to evaluate the possible role of endoplasmic reticulum (ER) stress in the induction of insulin resistance by glucosamine in skeletal muscle cells....

  3. Cardiac integrins the ties that bind.

    Science.gov (United States)

    Simpson, D G; Reaves, T A; Shih, D T; Burgess, W; Borg, T K; Terracio, L

    1998-01-01

    An elaborate series of morphogenetic events must be precisely coordinated during development to promote the formation of the elaborate three-dimensional structure of the normal heart. In this study we focus on discussing how interconnections between the cardiac myocyte and its surrounding environment regulate cardiac form and function. In vitro experiments from our laboratories provide direct evidence that cardiac cell shape is regulated by a dynamic interaction between constituents of the extracellular matrix (ECM) and by specific members of the integrin family of matrix receptors. Our data indicates that phenotypic information is stored in the tertiary structure and chemical identity of the ECM. This information appears to be actively communicated and transduced by the α1β1 integrin molecule into an intracellular signal that regulates cardiac cell shape and myofibrillar organization. In this study we have assessed the phenotypic consequences of suppressing the expression and accumulation of the α1 integrin molecule in aligned cultures of cardiac myocytes. In related experiments we have examined how the overexpression of α2 and α5 integrin, integrins normally not present or present at very low copy number on the cell surface of neonatal cardiac myocytes, affect cardiac protein metabolism. We also consider how biochemical signals and the mechanical signals mediated by the integrins may converge on common intracellular signaling pathways in the heart. Experiments with the whole embryo culture system indicate that angiotensin II, a peptide that carries information concerning cardiac load, plays a role in controling cardiac looping and the proliferation of myofibrils during development.

  4. Digital subtraction angiography in cardiac diseases

    International Nuclear Information System (INIS)

    Choi, Deuk Lin; Kim, Ki Jeong

    1986-01-01

    DSA was done in 133 examinations of 128 patients during 2 years consist of 9 examination of IV DSA and 124 examination of selective cardiac DSA after cardiac catheterization. Open heart surgery was performed in 90 patients and 12 patients showed discrepancy between pre-and post operative diagnosis, showing a total 86.7% of diagnostic accuracy with DSA. We experienced the significant reduction in dose of contrast media, 30-40% of dose of conventional cardiac angiography. It is concluded that DSA is useful in the evaluation of septal defects, valvular disease and other congenital heart disease. DSA is an accurate simple and safe method in evaluating of cardiac diseases.

  5. [Thromboelastography and its use in cardiac surgery].

    Science.gov (United States)

    Ak, Koray; Atalan, Nazan; Tekeli, Atike; Işbir, Selim; Civelek, Ali; Emekli, Nesrin; Arsan, Sinan

    2008-04-01

    Thromboelastography is an alternative method to conventional coagulation tests for the general evaluation of hemostatic system. Cardiac surgery with cardiopulmonary bypass is accomplished by complex alterations of hemostasis, including acquired dysfunction of platelets, consumption coagulopathy and increased fibrinolysis. Despite major advances in blood conservation methods and perioperative care of the patients, transfusion rates in cardiac surgery remain high. Thromboelastography has an ability to assess almost all components of haemostatic system globally. Currently, thromboelastography is used with standard coagulation tests to decrease the microvascular bleeding and homologous blood transfusion in cardiac surgery with cardiopulmonary bypass. In this review, we aimed to discuss thromboelastography technology and its usage in cardiac surgery.

  6. Radiation exposure of children during cardiac catheterisation

    International Nuclear Information System (INIS)

    Popp, W.

    1979-01-01

    It is well known that in adults, cardiac catheterisation involves the highest possible radiation exposure for a single examination. The paper now investigates the radiation exposure in paediatric cardiac cathetrisations. Dosimeters attached to the children during the examination were used as well as phantom measurements under the conditions of cardiac catheterisation. With the aid of the phantom, also the total energy absorption during an examination procedure was determined. This value was estimated to be 80 mJ. In spite of the high individual exposure, the contribution to the population exposure is low due to the small number of cardiac catheterisations. (orig.) 891 AJ/orig. 892 MKO [de

  7. circHIPK2-mediated σ-1R promotes endoplasmic reticulum stress in human pulmonary fibroblasts exposed to silica.

    Science.gov (United States)

    Cao, Zhouli; Xiao, Qingling; Dai, Xiaoniu; Zhou, Zewei; Jiang, Rong; Cheng, Yusi; Yang, Xiyue; Guo, Huifang; Wang, Jing; Xi, Zhaoqing; Yao, Honghong; Chao, Jie

    2017-12-13

    Silicosis is characterized by fibroblast accumulation and excessive deposition of extracellular matrix. Although the roles of SiO 2 -induced chemokines and cytokines released from alveolar macrophages have received significant attention, the direct effects of SiO 2 on protein production and functional changes in pulmonary fibroblasts have been less extensively studied. Sigma-1 receptor, which has been associated with cell proliferation and migration in the central nervous system, is expressed in the lung, but its role in silicosis remains unknown. To elucidate the role of sigma-1 receptor in fibrosis induced by silica, both the upstream molecular mechanisms and the functional effects on cell proliferation and migration were investigated. Both molecular biological assays and pharmacological techniques, combined with functional experiments, such as migration and proliferation, were applied in human pulmonary fibroblasts from adults to analyze the molecular and functional changes induced by SiO 2 . SiO 2 induced endoplasmic reticulum stress in association with enhanced expression of sigma-1 receptor. Endoplasmic reticulum stress promoted migration and proliferation of human pulmonary fibroblasts-adult exposed to SiO 2 , inducing the development of silicosis. Inhibition of sigma-1 receptor ameliorated endoplasmic reticulum stress and fibroblast functional changes induced by SiO 2 . circHIPK2 is involved in the regulation of sigma-1 receptor in human pulmonary fibroblasts-adult exposed to SiO 2 . Our study elucidated a link between SiO 2 -induced fibrosis and sigma-1 receptor signaling, thereby providing novel insight into the potential use of sigma-1 receptor/endoplasmic reticulum stress in the development of novel therapeutic strategies for silicosis treatment.

  8. Differential Impacts of Soybean and Fish Oils on Hepatocyte Lipid Droplet Accumulation and Endoplasmic Reticulum Stress in Primary Rabbit Hepatocytes

    OpenAIRE

    Zhu, Xueping; Xiao, Zhihui; Xu, Yumin; Zhao, Xingli; Cheng, Ping; Cui, Ningxun; Cui, Mingling; Li, Jie; Zhu, Xiaoli

    2016-01-01

    Parenteral nutrition-associated liver disease (PNALD) is a severe ailment associated with long-term parenteral nutrition. Soybean oil-based lipid emulsions (SOLE) are thought to promote PNALD development, whereas fish oil-based lipid emulsions (FOLE) are thought to protect against PNALD. This study aimed to investigate the effects of SOLE and FOLE on primary rabbit hepatocytes. The results reveal that SOLE caused significant endoplasmic reticulum (ER) and mitochondrial damage, ultimately resu...

  9. Endoplasmic reticulum-to-Golgi transitions upon herpes virus infection [version 2; referees: 1 approved, 3 approved with reservations

    Directory of Open Access Journals (Sweden)

    Peter Wild

    2018-02-01

    Full Text Available Background: Herpesvirus capsids are assembled in the nucleus, translocated to the perinuclear space by budding, acquiring tegument and envelope, or released to the cytoplasm via impaired nuclear envelope. One model proposes that envelopment, “de-envelopment” and “re-envelopment” is essential for production of infectious virus. Glycoproteins gB/gH were reported to be essential for de-envelopment, by fusion of the “primary” envelope with the outer nuclear membrane. Yet, a high proportion of enveloped virions generated from genomes with deleted gB/gH were found in the cytoplasm and extracellular space, suggesting the existence of alternative exit routes. Methods: We investigated the relatedness between the nuclear envelope and membranes of the endoplasmic reticulum and Golgi complex, in cells infected with either herpes simplex virus 1 (HSV-1 or a Us3 deletion mutant thereof, or with bovine herpesvirus 1 (BoHV-1 by transmission and scanning electron microscopy, employing freezing technique protocols. Results:  The Golgi complex is a compact entity in a juxtanuclear position covered by a membrane on the cis face. Golgi membranes merge with membranes of the endoplasmic reticulum forming an entity with the perinuclear space. All compartments contained enveloped virions. After treatment with brefeldin A, HSV-1 virions aggregated in the perinuclear space and endoplasmic reticulum, while infectious progeny virus was still produced. Conclusions: The data suggest that virions derived by budding at nuclear membranes are intraluminally transported from the perinuclear space via Golgi -endoplasmic reticulum transitions into Golgi cisternae for packaging. Virions derived by budding at nuclear membranes are infective like Us3 deletion mutants, which  accumulate in the perinuclear space. Therefore, i de-envelopment followed by re-envelopment is not essential for production of infective progeny virus, ii the process taking place at the outer nuclear

  10. Oxysterol-binding Protein Activation at Endoplasmic Reticulum-Golgi Contact Sites Reorganizes Phosphatidylinositol 4-Phosphate Pools*

    OpenAIRE

    Goto, Asako; Charman, Mark; Ridgway, Neale D.

    2015-01-01

    Oxysterol-binding protein (OSBP) exchanges cholesterol and phosphatidylinositol 4-phosphate (PI-4P) at contact sites between the endoplasmic reticulum (ER) and the trans-Golgi/trans-Golgi network. 25-Hydroxycholesterol (25OH) competitively inhibits this exchange reaction in vitro and causes the constitutive localization of OSBP at the ER/Golgi interface and PI-4P-dependent recruitment of ceramide transfer protein (CERT) for sphingomyelin synthesis. We used PI-4P probes and mass analysis to de...

  11. Taurine protects cisplatin induced cardiotoxicity by modulating inflammatory and endoplasmic reticulum stress responses.

    Science.gov (United States)

    Chowdhury, Sayantani; Sinha, Krishnendu; Banerjee, Sharmistha; Sil, Parames C

    2016-11-12

    Oxidative stress, ER stress, inflammation, and apoptosis results in the pathogenesis of cisplatin-induced cardiotoxicity. The present study was designed to investigate the signaling mechanisms involved in the ameliorating effect of taurine, a conditionally essential amino acid, against cisplatin-mediated cardiac ER stress dependent apoptotic death and inflammation. Mice were simultaneously treated with taurine (150 mg kg -1 body wt, i.p.) and cisplatin (10 mg kg -1 body wt, i.p.) for a week. Cisplatin exposure significantly altered serum creatine kinase and troponin T levels. In addition, histological studies revealed disintegration in the normal radiation pattern of cardiac muscle fibers. However, taurine administration could abate such adverse effects of cisplatin. Taurine administration significantly mitigated the reactive oxygen species production, alleviated the overexpression of nuclear factor-κB (NF-κB), and inhibited the elevation of proinflammatoy cytokines, adhesion molecules, and chemokines. Cisplatin exposure resulted in the unfolded protein response (UPR)-regulated CCAAT/enhancer binding protein (CHOP) up-regulation, induction of GRP78: a marker of ER stress and eIF2α signaling. Increase in calpain-1 expression level, activation of caspase-12 and caspase-3, cleavage of the PARP protein as well as the inhibition of antiapoptotic protein Bcl-2 were reflected on cisplatin-triggered apoptosis. Taurine could, however, combat against such cisplatin induced cardiac-abnormalities. The above mentioned findings suggest that taurine plays a beneficial role in providing protection against cisplatin-induced cardiac damage by modulating inflammatory responses and ER stress. © 2016 BioFactors, 42(6):647-664, 2016. © 2016 International Union of Biochemistry and Molecular Biology.

  12. Selective modulation of endoplasmic reticulum stress markers in prostate cancer cells by a standardized mangosteen fruit extract.

    Directory of Open Access Journals (Sweden)

    Gongbo Li

    Full Text Available The increased proliferation of cancer cells is directly dependent on the increased activity of the endoplasmic reticulum (ER machinery which is responsible for protein folding, assembly, and transport. In fact, it is so critical that perturbations in the endoplasmic reticulum can lead to apoptosis. This carefully regulated organelle represents a unique target of cancer cells while sparing healthy cells. In this study, a standardized mangosteen fruit extract (MFE was evaluated for modulating ER stress proteins in prostate cancer. Two human prostate cancer cell lines, 22Rv1 and LNCaP, and prostate epithelial cells (PrECs procured from two patients undergoing radical prostatectomy were treated with MFE. Flow cytometry, MTT, BrdU and Western blot were used to evaluate cell apoptosis, viability, proliferation and ER stress. Next, we evaluated MFE for microsomal stability and anti-cancer activity in nude mice. MFE induced apoptosis, decreased viability and proliferation in prostate cancer cells. MFE increased the expression of ER stress proteins. Interestingly, MFE selectively promotes ER stress in prostate cancer cells while sparing PrECs. MFE suppressed tumor growth in a xenograft tumor model without obvious toxicity. Mangosteen fruit extract selectively promotes endoplasmic reticulum stress in cancer cells while sparing non-tumorigenic prostate epithelial cells. Furthermore, in an in vivo setting mangosteen fruit extract significantly reduces xenograft tumor formation.

  13. Selective modulation of endoplasmic reticulum stress markers in prostate cancer cells by a standardized mangosteen fruit extract.

    Science.gov (United States)

    Li, Gongbo; Petiwala, Sakina M; Pierce, Dana R; Nonn, Larisa; Johnson, Jeremy J

    2013-01-01

    The increased proliferation of cancer cells is directly dependent on the increased activity of the endoplasmic reticulum (ER) machinery which is responsible for protein folding, assembly, and transport. In fact, it is so critical that perturbations in the endoplasmic reticulum can lead to apoptosis. This carefully regulated organelle represents a unique target of cancer cells while sparing healthy cells. In this study, a standardized mangosteen fruit extract (MFE) was evaluated for modulating ER stress proteins in prostate cancer. Two human prostate cancer cell lines, 22Rv1 and LNCaP, and prostate epithelial cells (PrECs) procured from two patients undergoing radical prostatectomy were treated with MFE. Flow cytometry, MTT, BrdU and Western blot were used to evaluate cell apoptosis, viability, proliferation and ER stress. Next, we evaluated MFE for microsomal stability and anti-cancer activity in nude mice. MFE induced apoptosis, decreased viability and proliferation in prostate cancer cells. MFE increased the expression of ER stress proteins. Interestingly, MFE selectively promotes ER stress in prostate cancer cells while sparing PrECs. MFE suppressed tumor growth in a xenograft tumor model without obvious toxicity. Mangosteen fruit extract selectively promotes endoplasmic reticulum stress in cancer cells while sparing non-tumorigenic prostate epithelial cells. Furthermore, in an in vivo setting mangosteen fruit extract significantly reduces xenograft tumor formation.

  14. Accelerated recovery after cardiac operations.

    Science.gov (United States)

    Kaplan, Mehmet; Kut, Mustafa Sinan; Yurtseven, Nurgul; Cimen, Serdar; Demirtas, Mahmut Murat

    2002-01-01

    The accelerated-recovery approach, involving early extubation, early mobility, decreased duration of intensive care unit stay, and decreased duration of hospitalization has recently become a controversial issue in cardiac surgery. We investigated timing of extubation, length of intensive care unit stay, and duration of hospitalization in 225 consecutive cardiac surgery patients. Of the 225 patients, 139 were male and 86 were female; average age was 49.73 +/- 16.95 years. Coronary artery bypass grafting was performed in 127 patients; 65 patients underwent aortic and/or mitral or pulmonary valvular operations; 5 patients underwent valvular plus coronary artery operations; and in 28 patients surgical interventions for congenital anomalies were carried out. The accelerated-recovery approach could be applied in 169 of the 225 cases (75.11%). Accelerated-recovery patients were extubated after an average of 3.97 +/- 1.59 hours, and the average duration of stay in the intensive care unit was 20.93 +/- 2.44 hours for these patients. Patients were discharged if they met all of the following criteria: hemodynamic stability, cooperativeness, ability to initiate walking exercises within wards, lack of pathology in laboratory investigations, and psychological readiness for discharge. Mean duration of hospitalization for accelerated-recovery patients was 4.24 +/- 0.75 days. Two patients (1.18%) who were extubated within the first 6 hours required reintubation. Four patients (2.36%) who were sent to the wards returned to intensive care unit due to various reasons and 6 (3.55%) of the discharged patients were rehospitalized. Approaches for decreasing duration of intubation, intensive care unit stay and hospitalization may be applied in elective and uncomplicated cardiac surgical interventions with short duration of aortic cross-clamping and cardiopulmonary bypass, without risking patients. Frequencies of reintubation, return to intensive care unit, and rehospitalization are quite

  15. Imaging features of cardiac myxoma

    International Nuclear Information System (INIS)

    Yang Youyou; Zheng Lili; Li Xiangmin; Zhou Xuhui; Kuang Jianyi; Zhang Wenzhao

    2007-01-01

    Objective: To study the imaging features of cardiac myxoma and their diagnostic values. Methods: Twenty-two patrents with cardiac myxoma were reviewed retrospectively for the clinical, pathologic, and radiologic findings. Posteroanterior and lateral chest radiographs, American Imatron C-150 XP Electron Beam CT examination, and Germany Siemens 1.5T Magnetom Vision MR scan were performed on every patient. Results: (1) Radiographs of 17 patients with left atrial myxoma showed evidence of mitral valve obstruction in 14(82.3%), radiographs of 5 patients with right atrial myxoma demonstrated right atrium enlargement in 3(60%) respectively. (2) CT scans of 22 myxomas demonstrated 18 (81.8%) lesions were hypoattenuated and 4 (19.1%) were isoattenuated relative to the myocardium. Calcification or ossification was seen in 3 patients. All myxomas apart from massive one were found attaching to the atrial septum. Movie mode could dis- play the movement of myxoma across the atrioventicular valves. (3) MRI studies of 22 myxomas showed 19 (86.3%) heterogeneous signal intensity and 3 (13.7%) homogeneous. They exhibited slight high or homogeneous signal intensity with both T 1 - and T 2 -weighted sequences, and low signal intensity with cine gradient recalled echo sequences. Point of attachment was visible in 21 (95.4%) cases. Conclusion: The typical radiograph sign of cardiac myxomas is mitral valve obstruction, CT and MR can demonstrate intracavitary lobular masses attacthing to artrial spetum. The latter two kinds of examinations not only provide accurate assessment of the size, location, and attachment point of these lesions, but also have important qualitative diagnostic advantage. (authors)

  16. Surviving endoplasmic reticulum stress is coupled to altered chondrocyte differentiation and function.

    Directory of Open Access Journals (Sweden)

    Kwok Yeung Tsang

    2007-03-01

    Full Text Available In protein folding and secretion disorders, activation of endoplasmic reticulum (ER stress signaling (ERSS protects cells, alleviating stress that would otherwise trigger apoptosis. Whether the stress-surviving cells resume normal function is not known. We studied the in vivo impact of ER stress in terminally differentiating hypertrophic chondrocytes (HCs during endochondral bone formation. In transgenic mice expressing mutant collagen X as a consequence of a 13-base pair deletion in Col10a1 (13del, misfolded alpha1(X chains accumulate in HCs and elicit ERSS. Histological and gene expression analyses showed that these chondrocytes survived ER stress, but terminal differentiation is interrupted, and endochondral bone formation is delayed, producing a chondrodysplasia phenotype. This altered differentiation involves cell-cycle re-entry, the re-expression of genes characteristic of a prehypertrophic-like state, and is cell-autonomous. Concomitantly, expression of Col10a1 and 13del mRNAs are reduced, and ER stress is alleviated. ERSS, abnormal chondrocyte differentiation, and altered growth plate architecture also occur in mice expressing mutant collagen II and aggrecan. Alteration of the differentiation program in chondrocytes expressing unfolded or misfolded proteins may be part of an adaptive response that facilitates survival and recovery from the ensuing ER stress. However, the altered differentiation disrupts the highly coordinated events of endochondral ossification culminating in chondrodysplasia.

  17. Endoplasmic Reticulum Stress Cooperates in Zearalenone-Induced Cell Death of RAW 264.7 Macrophages

    Directory of Open Access Journals (Sweden)

    Fenglei Chen

    2015-08-01

    Full Text Available Zearalenone (ZEA is a fungal mycotoxin that causes cell apoptosis and necrosis. However, little is known about the molecular mechanisms of ZEA toxicity. The objective of this study was to explore the effects of ZEA on the proliferation and apoptosis of RAW 264.7 macrophages and to uncover the signaling pathway underlying the cytotoxicity of ZEA in RAW 264.7 macrophages. This study demonstrates that the endoplasmic reticulum (ER stress pathway cooperated in ZEA-induced cell death of the RAW 264.7 macrophages. Our results show that ZEA treatment reduced the viability of RAW 264.7 macrophages in a dose- and time-dependent manner as shown by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay (MTT and flow cytometry assay. Western blots analysis revealed that ZEA increased the expression of glucose-regulated protein 78 (GRP78 and CCAAT/enhancer binding protein homologous protein (CHOP, two ER stress-related marker genes. Furthermore, treating the cells with the ER stress inhibitors 4-phenylbutyrate (4-PBA or knocking down CHOP, using lentivirus encoded short hairpin interfering RNAs (shRNAs, significantly diminished the ZEA-induced increases in GRP78 and CHOP, and cell death. In summary, our results suggest that ZEA induces the apoptosis and necrosis of RAW 264.7 macrophages in a dose- and time-dependent manner via the ER stress pathway in which the activation of CHOP plays a critical role.

  18. BiP clustering facilitates protein folding in the endoplasmic reticulum.

    Directory of Open Access Journals (Sweden)

    Marc Griesemer

    2014-07-01

    Full Text Available The chaperone BiP participates in several regulatory processes within the endoplasmic reticulum (ER: translocation, protein folding, and ER-associated degradation. To facilitate protein folding, a cooperative mechanism known as entropic pulling has been proposed to demonstrate the molecular-level understanding of how multiple BiP molecules bind to nascent and unfolded proteins. Recently, experimental evidence revealed the spatial heterogeneity of BiP within the nuclear and peripheral ER of S. cerevisiae (commonly referred to as 'clusters'. Here, we developed a model to evaluate the potential advantages of accounting for multiple BiP molecules binding to peptides, while proposing that BiP's spatial heterogeneity may enhance protein folding and maturation. Scenarios were simulated to gauge the effectiveness of binding multiple chaperone molecules to peptides. Using two metrics: folding efficiency and chaperone cost, we determined that the single binding site model achieves a higher efficiency than models characterized by multiple binding sites, in the absence of cooperativity. Due to entropic pulling, however, multiple chaperones perform in concert to facilitate the resolubilization and ultimate yield of folded proteins. As a result of cooperativity, multiple binding site models used fewer BiP molecules and maintained a higher folding efficiency than the single binding site model. These insilico investigations reveal that clusters of BiP molecules bound to unfolded proteins may enhance folding efficiency through cooperative action via entropic pulling.

  19. Docosahexaenoic acid inhibits monocrotaline-induced pulmonary hypertension via attenuating endoplasmic reticulum stress and inflammation.

    Science.gov (United States)

    Chen, Rui; Zhong, Wei; Shao, Chen; Liu, Peijing; Wang, Cuiping; Wang, Zhongqun; Jiang, Meiping; Lu, Yi; Yan, Jinchuan

    2018-02-01

    Endoplasmic reticulum (ER) stress and inflammation contribute to pulmonary hypertension (PH) pathogenesis. Previously, we confirmed that docosahexaenoic acid (DHA) could improve hypoxia-induced PH. However, little is known about the link between DHA and monocrotaline (MCT)-induced PH. Our aims were, therefore, to evaluate the effects and molecular mechanisms of DHA on MCT-induced PH in rats. Rat PH was induced by MCT. Rats were treated with DHA daily in the prevention group (following MCT injection) and the reversal group (after MCT injection for 2 wk) by gavage. After 4 wk, mean pulmonary arterial pressure (mPAP), right ventricular (RV) hypertrophy index, and morphological and immunohistochemical analyses were evaluated. Rat pulmonary artery smooth muscle cells (PASMCs) were used to investigate the effects of DHA on cell proliferation stimulated by platelet-derived growth factor (PDGF)-BB. DHA decreased mPAP and attenuated pulmonary vascular remodeling and RV hypertrophy, which were associated with suppressed ER stress. DHA blocked the mitogenic effect of PDGF-BB on PASMCs and arrested the cell cycle via inhibiting nuclear factor of activated T cells-1 (NFATc1) expression and activation and regulating cell cycle-related proteins. Moreover, DHA ameliorated inflammation in lung and suppressed macrophage and T lymphocyte accumulation in lung and adventitia of resistance pulmonary arteries. These findings suggest that DHA could protect against MCT-induced PH by reducing ER stress, suppressing cell proliferation and inflammation.

  20. Retention of CXCR4 in the endoplasmic reticulum blocks dissemination of a T cell hybridoma.

    Science.gov (United States)

    Zeelenberg, I S; Ruuls-Van Stalle, L; Roos, E

    2001-07-01

    The dissemination of T cell hybridomas to multiple nonhematopoietic tissues is blocked by pertussis toxin, suggesting the involvement of a chemokine. To study whether this chemokine is SDF-1, we employed a strategy proposed previously for gene therapy of AIDS, whereby the SDF-1 receptor CXCR4 (also a coreceptor for HIV) is retained in the endoplasmic reticulum (ER) and fails to reach the cell surface. We transfected SDF-1, carrying an ER retention sequence, into a T cell hybridoma. This altered chemokine is retained in the ER, where it binds CXCR4 and prevents the latter protein from reaching the surface. These cells failed to migrate toward SDF-1 or to invade fibroblast monolayers, although they could still migrate toward thymus and activation-regulated chemokine (TARC) and invade TARC-treated monolayers. Furthermore, the ability of the transfected cells to disseminate to multiple organs upon intravenous injection into mice was abolished. This dissemination reflects the in vivo migration patterns of activated and memory T cells into nonhematopoietic tissues, which is thus likely to depend on CXCR4. Attempts to block CXCR4 function as a therapy for AIDS may affect this migration with consequences for T cell function. Our results also suggest a decisive role for CXCR4 in the dissemination of hematopoietic malignancies expressing this receptor.