Sample records for factor induced calcium

  1. Calcium hydroxide suppresses Porphyromonas endodontalis lipopolysaccharide-induced bone destruction.

    PubMed

    Guo, J; Yang, D; Okamura, H; Teramachi, J; Ochiai, K; Qiu, L; Haneji, T

    2014-05-01

    Porphyromonas endodontalis and its main virulence factor, lipopolysaccharide (LPS), are associated with the development of periapical diseases and alveolar bone loss. Calcium hydroxide is commonly used for endodontic therapy. However, the effects of calcium hydroxide on the virulence of P. endodontalis LPS and the mechanism of P. endodontalis LPS-induced bone destruction are not clear. Calcium hydroxide rescued the P. endodontalis LPS-suppressed viability of MC3T3-E1 cells and activity of nuclear factor-κB (NF-κB) in these cells, resulting in the reduced expression of interleukin-6 and tumor necrosis factor-α. In addition, calcium hydroxide inhibited P. endodontalis LPS-induced osteoclastogenesis by decreasing the activities of NF-κB, p38, and ERK1/2 and the expression of nuclear factor of activated T-cell cytoplasmic 1 in RAW264.7 cells. Calcium hydroxide also rescued the P. endodontalis LPS-induced osteoclastogenesis and bone destruction in mouse calvaria. Taken together, our present results indicate that calcium hydroxide suppressed bone destruction by attenuating the virulence of P. endodontalis LPS on bone cells.

  2. Induced calcium carbonate precipitation using Bacillus species.

    PubMed

    Seifan, Mostafa; Samani, Ali Khajeh; Berenjian, Aydin

    2016-12-01

    Microbially induced calcium carbonate precipitation is an emerging process for the production of self-healing concrete. This study was aimed to investigate the effects and optimum conditions on calcium carbonate biosynthesis. Bacillus licheniformis, Bacillus sphaericus, yeast extract, urea, calcium chloride and aeration were found to be the most significant factors affecting the biomineralization of calcium carbonate. It was noticed that the morphology of microbial calcium carbonate was mainly affected by the genera of bacteria (cell surface properties), the viscosity of the media and the type of electron acceptors (Ca 2+ ). The maximum calcium carbonate concentration of 33.78 g/L was achieved at the optimum conditions This value is the highest concentration reported in the literature.

  3. Calcium Overload Accelerates Phosphate-Induced Vascular Calcification Via Pit-1, but not the Calcium-Sensing Receptor.

    PubMed

    Masumoto, Asuka; Sonou, Tomohiro; Ohya, Masaki; Yashiro, Mitsuru; Nakashima, Yuri; Okuda, Kouji; Iwashita, Yuko; Mima, Toru; Negi, Shigeo; Shigematsu, Takashi

    2017-07-01

    Vascular calcification (VC) is a risk factor of cardiovascular and all-cause mortality in patients with chronic kidney disease (CKD). CKD-mineral and bone metabolism disorder is an important problem in patients with renal failure. Abnormal levels of serum phosphate and calcium affect CKD-mineral and bone metabolism disorder and contribute to bone disease, VC, and cardiovascular disease. Hypercalcemia is a contributing factor in progression of VC in patients with CKD. However, the mechanisms of how calcium promotes intracellular calcification are still unclear. This study aimed to examine the mechanisms underlying calcium-induced calcification in a rat aortic tissue culture model. Aortic segments from 7-week-old male Sprague-Dawley rats were cultured in serum-supplemented medium for 10 days. We added high calcium (HiCa; calcium 3.0 mM) to high phosphate (HPi; phosphate 3.8 mM) medium to accelerate phosphate and calcium-induced VC. We used phosphonoformic acid and the calcimimetic R-568 to determine whether the mechanism of calcification involves Pit-1 or the calcium-sensing receptor. Medial VC was significantly augmented by HPi+HiCa medium compared with HPi alone (300%, p<0.05), and was associated with upregulation of Pit-1 protein. Pit-1 protein concentrations in HPi+HiCa medium were greater than those in HPi medium. Phosphonoformic acid completely negated the augmentation of medial VC induced by HPi+HiCa. R-568 had no additive direct effect on medial VC. These results indicated that exposure to HPi+HiCa accelerates medial VC, and this is mediated through Pit-1, not the calcium-sensing receptor.

  4. Mechanically induced intercellular calcium communication in confined endothelial structures.

    PubMed

    Junkin, Michael; Lu, Yi; Long, Juexuan; Deymier, Pierre A; Hoying, James B; Wong, Pak Kin

    2013-03-01

    Calcium signaling in the diverse vascular structures is regulated by a wide range of mechanical and biochemical factors to maintain essential physiological functions of the vasculature. To properly transmit information, the intercellular calcium communication mechanism must be robust against various conditions in the cellular microenvironment. Using plasma lithography geometric confinement, we investigate mechanically induced calcium wave propagation in networks of human umbilical vein endothelial cells organized. Endothelial cell networks with confined architectures were stimulated at the single cell level, including using capacitive force probes. Calcium wave propagation in the network was observed using fluorescence calcium imaging. We show that mechanically induced calcium signaling in the endothelial networks is dynamically regulated against a wide range of probing forces and repeated stimulations. The calcium wave is able to propagate consistently in various dimensions from monolayers to individual cell chains, and in different topologies from linear patterns to cell junctions. Our results reveal that calcium signaling provides a robust mechanism for cell-cell communication in networks of endothelial cells despite the diversity of the microenvironmental inputs and complexity of vascular structures. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Teaching Calcium-Induced Calcium Release in Cardiomyocytes Using a Classic Paper by Fabiato

    ERIC Educational Resources Information Center

    Liang, Willmann

    2008-01-01

    This teaching paper utilizes the materials presented by Dr. Fabiato in his review article entitled "Calcium-induced release of calcium from the cardiac sarcoplasmic reticulum." In the review, supporting evidence of calcium-induced calcium release (CICR) is presented. Data concerning potential objections to the CICR theory are discussed as well. In…

  6. Calcium-mediated signaling and calmodulin-dependent kinase regulate hepatocyte-inducible nitric oxide synthase expression.

    PubMed

    Zhang, Baochun; Crankshaw, Will; Nesemeier, Ryan; Patel, Jay; Nweze, Ikenna; Lakshmanan, Jaganathan; Harbrecht, Brian G

    2015-02-01

    Induced nitric oxide synthase (iNOS) is induced in hepatocytes by shock and inflammatory stimuli. Excessive NO from iNOS mediates shock-induced hepatic injury and death, so understanding the regulation of iNOS will help elucidate the pathophysiology of septic shock. In vitro, cytokines induce iNOS expression through activation of signaling pathways including mitogen-activated protein kinases and nuclear factor κB. Cytokines also induce calcium (Ca(2+)) mobilization and activate calcium-mediated intracellular signaling pathways, typically through activation of calmodulin-dependent kinases (CaMK). Calcium regulates NO production in macrophages but the role of calcium and calcium-mediated signaling in hepatocyte iNOS expression has not been defined. Primary rat hepatocytes were isolated, cultured, and induced to produce NO with proinflammatory cytokines. Calcium mobilization and Ca(2+)-mediated signaling were altered with ionophore, Ca(2+) channel blockers, and inhibitors of CaMK. The Ca(2+) ionophore A23187 suppressed cytokine-stimulated NO production, whereas Ethylene glycol tetraacetic acid and nifedipine increased NO production, iNOS messenger RNA, and iNOS protein expression. Inhibition of CaMK with KN93 and CBD increased NO production but the calcineurin inhibitor FK 506 decreased iNOS expression. These data demonstrate that calcium-mediated signaling regulates hepatocyte iNOS expression and does so through a mechanism independent of calcineurin. Changes in intracellular calcium levels may regulate iNOS expression during hepatic inflammation induced by proinflammatory cytokines. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Lack of voltage-dependent calcium channel opening during the calcium influx induced by progesterone in human sperm. Effect of calcium channel deactivation and inactivation.

    PubMed

    Guzmán-Grenfell, Alberto Martín; González-Martínez, Marco T

    2004-01-01

    Progesterone induces calcium influx and acrosomal exocytosis in human sperm. Pharmacologic evidence suggests that voltage-dependent calcium channels (VDCCs) are involved. In this study, membrane potential (Vm) and intracellular calcium concentration ([Ca(2+)](i)) were monitored simultaneously to assess the effect of VDCC gating on the calcium influx triggered by progesterone. Holding the Vm to values that maintained VDCCs in a deactivated (-71 mV) closed state inhibited the calcium influx induced by progesterone by approximately 40%. At this Vm, the acrosomal reaction induced by progesterone, but not by A23187, was inhibited. However, when the Vm was held at -15 mV (which maintains VDCCs in an inactivated closed state), the progesterone-induced calcium influx was stimulated. Furthermore, the progesterone and voltage-dependent calcium influxes were additive. These findings indicate that progesterone does not produce VDCC gating in human sperm.

  8. Astaxanthin attenuates glutamate-induced apoptosis via inhibition of calcium influx and endoplasmic reticulum stress.

    PubMed

    Lin, Xiaotong; Zhao, Yan; Li, Shanhe

    2017-07-05

    Astaxanthin (AST) is a carotenoid that has been shown to have neuroprotective effects. In this study, it was found that AST significantly inhibited glutamate-induced loss of cell viability and apoptosis. AST pretreatment attenuated glutamate-induced activation of caspase-3, reduction of anti-apoptotic protein Bcl-2, and increase of pro-apoptotic protein Bak. In addition, AST pretreatment suppressed the production of intracellular reactive oxygen species. AST treatment also prevented glutamate-induced increase of the level of activated p38 mitogen-activated protein kinase (MAPK), which has been shown to promote apoptotic events. Furthermore, AST treatment greatly reduced the elevation of intracellular calcium level induced by glutamate and inhibited the activity of calpain, a calcium-dependent protease that plays an important role in mediating apoptosis stimulated by calcium overload in cytoplasm. Both oxidative stress and calcium overload can lead to endoplasmic reticulum (ER) stress. C/EBP-homologous protein (CHOP) is a bZIP transcription factor that can be activated by ER stress and promotes apoptosis. Here we found that AST attenuated glutamate-induced elevation of CHOP and ER chaperone glucose-regulated protein (GRP78). Overall, these results suggested that AST might protect cells against glutamate-induced apoptosis through maintaining redox balance and inhibiting glutamate-induced calcium influx and ER stress. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Calcium-Induced Calcium Release during Action Potential Firing in Developing Inner Hair Cells

    PubMed Central

    Iosub, Radu; Avitabile, Daniele; Grant, Lisa; Tsaneva-Atanasova, Krasimira; Kennedy, Helen J.

    2015-01-01

    In the mature auditory system, inner hair cells (IHCs) convert sound-induced vibrations into electrical signals that are relayed to the central nervous system via auditory afferents. Before the cochlea can respond to normal sound levels, developing IHCs fire calcium-based action potentials that disappear close to the onset of hearing. Action potential firing triggers transmitter release from the immature IHC that in turn generates experience-independent firing in auditory neurons. These early signaling events are thought to be essential for the organization and development of the auditory system and hair cells. A critical component of the action potential is the rise in intracellular calcium that activates both small conductance potassium channels essential during membrane repolarization, and triggers transmitter release from the cell. Whether this calcium signal is generated by calcium influx or requires calcium-induced calcium release (CICR) is not yet known. IHCs can generate CICR, but to date its physiological role has remained unclear. Here, we used high and low concentrations of ryanodine to block or enhance CICR to determine whether calcium release from intracellular stores affected action potential waveform, interspike interval, or changes in membrane capacitance during development of mouse IHCs. Blocking CICR resulted in mixed action potential waveforms with both brief and prolonged oscillations in membrane potential and intracellular calcium. This mixed behavior is captured well by our mathematical model of IHC electrical activity. We perform two-parameter bifurcation analysis of the model that predicts the dependence of IHCs firing patterns on the level of activation of two parameters, the SK2 channels activation and CICR rate. Our data show that CICR forms an important component of the calcium signal that shapes action potentials and regulates firing patterns, but is not involved directly in triggering exocytosis. These data provide important insights

  10. Ethanol suppresses carbamylcholine-induced intracellular calcium oscillation in mouse pancreatic acinar cells.

    PubMed

    Yoon, Mi Na; Kim, Min Jae; Koong, Hwa Soo; Kim, Dong Kwan; Kim, Se Hoon; Park, Hyung Seo

    2017-09-01

    Oscillation of intracellular calcium levels is closely linked to initiating secretion of digestive enzymes from pancreatic acinar cells. Excessive alcohol consumption is known to relate to a variety of disorders in the digestive system, including the exocrine pancreas. In this study, we have investigated the role and mechanism of ethanol on carbamylcholine (CCh)-induced intracellular calcium oscillation in murine pancreatic acinar cells. Ethanol at concentrations of 30 and 100 mM reversibly suppressed CCh-induced Ca 2+ oscillation in a dose-dependent manner. Pretreatment of ethanol has no effect on the store-operated calcium entry induced by 10 μM of CCh. Ethanol significantly reduced the initial calcium peak induced by low concentrations of CCh and therefore, the CCh-induced dose-response curve of the initial calcium peak was shifted to the right by ethanol pretreatment. Furthermore, ethanol significantly dose-dependently reduced inositol 1,4,5-trisphosphate-induced calcium release from the internal stores in permeabilized acinar cells. These results provide evidence that excessive alcohol intake could impair cytosolic calcium oscillation through inhibiting calcium release from intracellular stores in mouse pancreatic acinar cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Dimebon Inhibits Calcium-Induced Swelling of Rat Brain Mitochondria But Does Not Alter Calcium Retention or Cytochrome C Release

    PubMed Central

    Naga, Kranthi Kumari

    2012-01-01

    Dimebon was originally introduced as an antihistamine and subsequently investigated as a possible therapeutic for a variety of disorders, including Alzheimer's disease. One putative mechanism underlying the neuroprotective properties of Dimebon is inhibition of mitochondrial permeability transition, based on the observation that Dimebon inhibited the swelling of rat liver mitochondria induced by calcium and other agents that induce permeability transition. Because liver and brain mitochondria differ substantially in their properties and response to conditions associated with opening of the permeability transition pore, we sought to determine whether Dimebon inhibited permeability transition in brain mitochondria. Dimebon reduced calcium-induced mitochondrial swelling but did not enhance the calcium retention capacity or impair calcium-induced cytochrome C release from non-synaptic mitochondria isolated from rat brain cerebral cortex. These findings indicate that Dimebon does not inhibit mitochondrial permeability transition, induced by excessive calcium uptake, in brain mitochondria. PMID:20625939

  12. Dimebon inhibits calcium-induced swelling of rat brain mitochondria but does not alter calcium retention or cytochrome C release.

    PubMed

    Naga, Kranthi Kumari; Geddes, James W

    2011-03-01

    Dimebon was originally introduced as an antihistamine and subsequently investigated as a possible therapeutic for a variety of disorders, including Alzheimer's disease. One putative mechanism underlying the neuroprotective properties of Dimebon is inhibition of mitochondrial permeability transition, based on the observation that Dimebon inhibited the swelling of rat liver mitochondria induced by calcium and other agents that induce permeability transition. Because liver and brain mitochondria differ substantially in their properties and response to conditions associated with opening of the permeability transition pore, we sought to determine whether Dimebon inhibited permeability transition in brain mitochondria. Dimebon reduced calcium-induced mitochondrial swelling but did not enhance the calcium retention capacity or impair calcium-induced cytochrome C release from non-synaptic mitochondria isolated from rat brain cerebral cortex. These findings indicate that Dimebon does not inhibit mitochondrial permeability transition, induced by excessive calcium uptake, in brain mitochondria.

  13. Resveratrol-induced antinociception is involved in calcium channels and calcium/caffeine-sensitive pools.

    PubMed

    Pan, Xiaoyu; Chen, Jiechun; Wang, Weijie; Chen, Ling; Wang, Lin; Ma, Quan; Zhang, Jianbo; Chen, Lichao; Wang, Gang; Zhang, Meixi; Wu, Hao; Cheng, Ruochuan

    2017-02-07

    Resveratrol has been widely investigated for its potential health properties, although little is known about its mechanism in vivo. Previous studies have indicated that resveratrol produces antinociceptive effects in mice. Calcium channels and calcium/caffeine-sensitive pools are reported to be associated with analgesic effect. The present study was to explore the involvement of Ca2+ channel and calcium/caffeine-sensitive pools in the antinociceptive response of resveratrol. Tail-flick test was used to assess antinociception in mice treated with resveratrol or the combinations of resveratrol with MK 801, nimodipine, CaCl2, ryanodine and ethylene glycol tetraacetic acid (EGTA), respectively. The Ca2+/calmodulin-dependent protein kinase II (CaMKII) and brain-derived neurotrophic factor (BDNF) levels in the spinal cord were also investigated when treated with the above drugs. The results showed that resveratrol increased the tail flick latency in the tail-flick test, in dose-dependent manner. N-methyl-D-aspartate (NMDA) glutamate receptor antagonist MK 801 potentiated the antinociceptive effects of sub-threshold dose of resveratrol at 10 mg/kg. Ca2+ channel blocker, however, abolished the antinociceptive effects of resveratrol. In contrast to these results, EGTA or ryanodine treatment (i.c.v.) potentiated resveratrol-induced antinociception. There was a significant decrease in p-CaMKII and an increase in BDNF expression in the spinal cord when combined with MK 801, nimodipine, ryanodine and EGTA. While an increase in p-CaMKII level and a decrease in BDNF expression were observed when high dose of resveratrol combined with CaCl2. These findings suggest that resveratrol exhibits the antinociceptive effects by inhibition of calcium channels and calcium/caffeine-sensitive pools.

  14. Calcium-Induced calcium release during action potential firing in developing inner hair cells.

    PubMed

    Iosub, Radu; Avitabile, Daniele; Grant, Lisa; Tsaneva-Atanasova, Krasimira; Kennedy, Helen J

    2015-03-10

    In the mature auditory system, inner hair cells (IHCs) convert sound-induced vibrations into electrical signals that are relayed to the central nervous system via auditory afferents. Before the cochlea can respond to normal sound levels, developing IHCs fire calcium-based action potentials that disappear close to the onset of hearing. Action potential firing triggers transmitter release from the immature IHC that in turn generates experience-independent firing in auditory neurons. These early signaling events are thought to be essential for the organization and development of the auditory system and hair cells. A critical component of the action potential is the rise in intracellular calcium that activates both small conductance potassium channels essential during membrane repolarization, and triggers transmitter release from the cell. Whether this calcium signal is generated by calcium influx or requires calcium-induced calcium release (CICR) is not yet known. IHCs can generate CICR, but to date its physiological role has remained unclear. Here, we used high and low concentrations of ryanodine to block or enhance CICR to determine whether calcium release from intracellular stores affected action potential waveform, interspike interval, or changes in membrane capacitance during development of mouse IHCs. Blocking CICR resulted in mixed action potential waveforms with both brief and prolonged oscillations in membrane potential and intracellular calcium. This mixed behavior is captured well by our mathematical model of IHC electrical activity. We perform two-parameter bifurcation analysis of the model that predicts the dependence of IHCs firing patterns on the level of activation of two parameters, the SK2 channels activation and CICR rate. Our data show that CICR forms an important component of the calcium signal that shapes action potentials and regulates firing patterns, but is not involved directly in triggering exocytosis. These data provide important insights

  15. Influence of calcium salts and bovine thrombin on growth factor release from equine platelet-rich gel supernatants.

    PubMed

    Giraldo, Carlos E; Álvarez, María E; Carmona, Jorge U

    2017-01-16

    To compare five activation methods in equine platelet-rich plasma (PRP) by determination of platelet-derived growth factor BB (PDGF-BB) and transforming growth factor beta 1 (TGF-β1) concentrations in platelet-rich gel (PRG) supernatants. Platelet-rich plasma from 20 horses was activated by calcium chloride (CC), calcium gluconate (CG), bovine thrombin (BT), and their combinations, BTCC and BTCG. Both growth factor concentrations in PRG supernatants were measured by ELISA and compared with plasma and platelet lysates (PL) over time. Growth factor concentrations were significantly lower in plasma and higher for all PRG supernatants. Platelet lysates contained a significantly lower concentration of PDGF-BB than PRG supernatants and a significantly higher concentration of TGF-β1 than PRG supernatants. Clots from PRP activated with sodium salts were more stable over time and had significant growth factor release, whereas CC produced gross salt deposition. Significant correlations were noticed for platelet with leukocyte concentrations in PRP (r s : 0.76), platelet counts in PRP with TGF-β1 concentrations in PRG supernatants (r s : 0.86), platelet counts in PRP with PDGF-BB concentrations in PRG supernatants (r s : 0.78), leukocyte counts in PRP with TGF-β1 concentrations in PRG supernatants (r s : 0.76), and PDGF-BB concentrations with activating substances (r s : 0.72). Calcium gluconate was the better substance to induce PRP activation. It induced growth factor release free from calcium precipitates in the clots. Use of BT alone or combined with calcium salts was not advantageous for growth factor release.

  16. High butyric acid amounts induce oxidative stress, alter calcium homeostasis, and cause neurite retraction in nerve growth factor-treated PC12 cells.

    PubMed

    Cueno, Marni E; Kamio, Noriaki; Seki, Keisuke; Kurita-Ochiai, Tomoko; Ochiai, Kuniyasu

    2015-07-01

    Butyric acid (BA) is a common secondary metabolite by-product produced by oral pathogenic bacteria and is detected in high amounts in the gingival tissue of patients with periodontal disease. Previous works have demonstrated that BA can cause oxidative stress in various cell types; however, this was never explored using neuronal cells. Here, we exposed nerve growth factor (NGF)-treated PC1(2) cells to varying BA concentrations (0.5, 1.0, 5.0 mM). We measured total heme, H(2)O(2), catalase, and calcium levels through biochemical assays and visualized the neurite outgrowth after BA treatment. Similarly, we determined the effects of other common periodontal short-chain fatty acids (SCFAs) on neurite outgrowth for comparison. We found that high (1.0 and 5.0 mM) BA concentrations induced oxidative stress and altered calcium homeostasis, whereas low (0.5 mM) BA concentration had no significant effect. Moreover, compared to other SCFAs, we established that only BA was able to induce neurite retraction.

  17. On the role of calcium in adrenocorticotropin-induced changes in mitochondrial pregnenolone synthesis.

    PubMed

    Farese, R V; Prudente, W J

    1978-10-01

    The importance of calcium in the ACTH-induced increase in adrenal mitochondrial pregnenolone synthesis was evaluated. In mitochondria prepared in the absence of EDTA and albumin, calcium enhanced the binding of cholesterol to cytochrome P-450 and subsequent pregnenolone synthesis. Although these effects of calcium were slightly greater in control than in ACTH-treated mitochondria, a sizeable effect of ACTH remained even at high calcium levels (500 micron). In mitochondria prepared from adrenals homogenized in fluid containing EDTA and albumin, ACTH-induced effects on pregnenolone synthesis were relatively poor unless calcium was added to the incubation mixture. High concentrations of added calcium (500 micron or greater) obviated the need for the labile protein required for ACTH-induced effects in intact mitochondria, presumably by disrupting mitochondria and allowing an "unrestrained" interaction of cholesterol with cytochrome P-450. Thus, cholesterol-rich mitochondria from ACTH plus cycloheximide-treated rats produced large amounts of pregnenolone when high (probably unphysiological) calcium concentrations were present. The present findings suggest that calcium is required at the mitochondrial level for ACTH-induced effects on pregnenolone synthesis, and the reported ACTH-induced increase in intraadrenal calcium may thus amplify the effects of ACTH on steroidogenesis. However, it seems unlikely that calcium is the agent primarily responsible for mediating the ACTH-induced steroidogenic effect at the mitochondrial level.

  18. [Role of melatonin in calcium overload-induced heart injury].

    PubMed

    Kong, Lingheng; Wei, Ming; Sun, Na; Zhu, Juanxia; Su, Xingli

    2017-06-28

    To investigate the role of melatonin in calcium overload-induced heart injury.
 Methods: Thirty-two rats were divided into 4 groups: a control group (Control), a melatonin control group (Mel), a calcium overload group (CaP), and a calcium overload plus melatonin group (Mel+CaP). Isolated Sprague Dawley male rat hearts underwent Langendorff perfusion. Left ventricular developed pressure (LVDP) was calculated to evaluate the myocardial performance. Triphenyltetrazolium chloride staining was used to measure the infarct size of myocardium. Lactate dehydrogenase (LDH) activity in the coronary flow was determined. The expressions of caspase-3 and cytochrome c were determined by Western blot. The pathological morphological changes in myocardial fiber were analyzed by HE staining.
 Results: Compared with the control group, calcium overload significantly induced an enlarged infarct size (P<0.01), accompanied by the disordered arrangement of myocardial fiber, up-regulation of cytochrome c and caspase-3 (P<0.01), and the increased activity of LDH (P<0.01). These effects were significantly attenuated by 10 μmol/L melatonin (P<0.01).
 Conclusion: Melatonin can alleviate calcium overload-induced heart injury.

  19. Role of calcium in growth inhibition induced by a novel cell surface sialoglycopeptide

    NASA Technical Reports Server (NTRS)

    Betz, N. A.; Westhoff, B. A.; Johnson, T. C.; Spooner, B. S. (Principal Investigator)

    1995-01-01

    Our laboratory has purified an 18 kDa cell surface sialoglycopeptide growth inhibitor (CeReS-18) from intact bovine cerebral cortex cells. Evidence presented here demonstrates that sensitivity to CeReS-18-induced growth inhibition in BALB-c 3T3 cells is influenced by calcium, such that a decrease in the calcium concentration in the growth medium results in an increase in sensitivity to CeReS-18. Calcium did not alter CeReS-18 binding to its cell surface receptor and CeReS-18 does not bind calcium directly. Addition of calcium, but not magnesium, to CeReS-18-inhibited 3T3 cells results in reentry into the cell cycle. A greater than 3-hour exposure to increased calcium is required for escape from CeReS-18-induced growth inhibition. The calcium ionophore ionomycin could partially mimic the effect of increasing extracellular calcium, but thapsigargin was ineffective in inducing escape from growth inhibition. Increasing extracellular calcium 10-fold resulted in an approximately 7-fold increase in total cell-associated 45Ca+2, while free intracellular calcium only increased approximately 30%. However, addition of CeReS-18 did not affect total cell-associated calcium or the increase in total cell-associated calcium observed with an increase in extracellular calcium. Serum addition induced mobilization of intracellular calcium and influx across the plasma membrane in 3T3 cells, and pretreatment of 3T3 cells with CeReS-18 appeared to inhibit these calcium mobilization events. These results suggest that a calcium-sensitive step exists in the recovery from CeReS-18-induced growth inhibition. CeReS-18 may inhibit cell proliferation through a novel mechanism involving altering the intracellular calcium mobilization/regulation necessary for cell cycle progression.

  20. Glutathione-Induced Calcium Shifts in Chick Retinal Glial Cells

    PubMed Central

    Freitas, Hercules R.; Ferraz, Gabriel; Ferreira, Gustavo C.; Ribeiro-Resende, Victor T.; Chiarini, Luciana B.; do Nascimento, José Luiz M.; Matos Oliveira, Karen Renata H.; Pereira, Tiago de Lima; Ferreira, Leonardo G. B.; Kubrusly, Regina C.; Faria, Robson X.

    2016-01-01

    Neuroglia interactions are essential for the nervous system and in the retina Müller cells interact with most of the neurons in a symbiotic manner. Glutathione (GSH) is a low-molecular weight compound that undertakes major antioxidant roles in neurons and glia, however, whether this compound could act as a signaling molecule in neurons and/or glia is currently unknown. Here we used embryonic avian retina to obtain mixed retinal cells or purified Müller glia cells in culture to evaluate calcium shifts induced by GSH. A dose response curve (0.1–10mM) showed that 5–10mM GSH, induced calcium shifts exclusively in glial cells (later labeled and identified as 2M6 positive cells), while neurons responded to 50mM KCl (labeled as βIII tubulin positive cells). BBG 100nM, a P2X7 blocker, inhibited the effects of GSH on Müller glia. However, addition of DNQX 70μM and MK-801 20μM, non-NMDA and NMDA blockers, had no effect on GSH calcium induced shift. Oxidized glutathione (GSSG) at 5mM failed to induce calcium mobilization in glia cells, indicating that the antioxidant and/or structural features of GSH are essential to promote elevations in cytoplasmic calcium levels. Indeed, a short GSH pulse (60s) protects Müller glia from oxidative damage after 30 min of incubation with 0.1% H2O2. Finally, GSH induced GABA release from chick embryonic retina, mixed neuron-glia or from Müller cell cultures, which were inhibited by BBG or in the absence of sodium. GSH also induced propidium iodide uptake in Müller cells in culture in a P2X7 receptor dependent manner. Our data suggest that GSH, in addition to antioxidant effects, could act signaling calcium shifts at the millimolar range particularly in Müller glia, and could regulate the release of GABA, with additional protective effects on retinal neuron-glial circuit. PMID:27078878

  1. Calcium-independent metal-ion catalytic mechanism of anthrax edema factor

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

    Shen, Yuequan; Zhukovskaya, Natalia L.; Guo, Qing

    2009-11-18

    Edema factor (EF), a key anthrax exotoxin, has an anthrax protective antigen-binding domain (PABD) and a calmodulin (CaM)-activated adenylyl cyclase domain. Here, we report the crystal structures of CaM-bound EF, revealing the architecture of EF PABD. CaM has N- and C-terminal domains and each domain can bind two calcium ions. Calcium binding induces the conformational change of CaM from closed to open. Structures of the EF-CaM complex show how EF locks the N-terminal domain of CaM into a closed conformation regardless of its calcium-loading state. This represents a mechanism of how CaM effector alters the calcium affinity of CaM andmore » uncouples the conformational change of CaM from calcium loading. Furthermore, structures of EF-CaM complexed with nucleotides show that EF uses two-metal-ion catalysis, a prevalent mechanism in DNA and RNA polymerases. A histidine (H351) further facilitates the catalysis of EF by activating a water to deprotonate 3'OH of ATP. Mammalian adenylyl cyclases share no structural similarity with EF and they also use two-metal-ion catalysis, suggesting the catalytic mechanism-driven convergent evolution of two structurally diverse adenylyl cyclases.« less

  2. Calcium influences sensitivity to growth inhibition induced by a cell surface sialoglycopeptide

    NASA Technical Reports Server (NTRS)

    Betz, N. A.; Fattaey, H. K.; Johnson, T. C.; Spooner, B. S. (Principal Investigator)

    1994-01-01

    While studies concerning mitogenic factors have been an important area of research for many years, much less is understood about the mechanisms of action of cell surface growth inhibitors. We have purified an 18 kDa cell surface sialoglycopeptide growth inhibitor (CeReS-18) which can reversibly inhibit the proliferation of diverse cell types. The studies discussed in this article show that three mouse keratinocyte cell lines exhibit sixty-fold greater sensitivity than other fibroblasts and epithelial-like cells to CeReS-18-induced growth inhibition. Growth inhibition induced by CeReS-18 treatment is a reversible process, and the three mouse keratinocyte cell lines exhibited either single or multiple cell cycle arrest points, although a predominantly G0/G1 cell cycle arrest point was exhibited in Swiss 3T3 fibroblasts. The sensitivity of the mouse keratinocyte cell lines to CeReS-18-induced growth inhibition was not affected by the degree of tumorigenic progression in the cell lines and was not due to differences in CeReS-18 binding affinity or number of cell surface receptors per cell. However, the sensitivity of both murine fibroblasts and keratinocytes could be altered by changing the extracellular calcium concentration, such that increased extracellular calcium concentrations resulted in decreased sensitivity to CeReS-18-induced proliferation inhibition. Thus the increased sensitivity of the murine keratinocyte cell lines to CeReS-18 could be ascribed to the low calcium concentration used in their propagation. Studies are currently under way investigating the role of calcium in CeReS-18-induced growth arrest. The CeReS-18 may serve as a very useful tool to study negative growth control and the signal transduction events associated with cell cycling.

  3. Comparative biology of sperm factors and fertilization-induced calcium signals across the animal kingdom.

    PubMed

    Kashir, Junaid; Deguchi, Ryusaku; Jones, Celine; Coward, Kevin; Stricker, Stephen A

    2013-10-01

    Fertilization causes mature oocytes or eggs to increase their concentrations of intracellular calcium ions (Ca²⁺) in all animals that have been examined, and such Ca²⁺ elevations, in turn, provide key activating signals that are required for non-parthenogenetic development. Several lines of evidence indicate that the Ca²⁺ transients produced during fertilization in mammals and other taxa are triggered by soluble factors that sperm deliver into oocytes after gamete fusion. Thus, for a broad-based analysis of Ca²⁺ dynamics during fertilization in animals, this article begins by summarizing data on soluble sperm factors in non-mammalian species, and subsequently reviews various topics related to a sperm-specific phospholipase C, called PLCζ, which is believed to be the predominant activator of mammalian oocytes. After characterizing initiation processes that involve sperm factors or alternative triggering mechanisms, the spatiotemporal patterns of Ca²⁺ signals in fertilized oocytes or eggs are compared in a taxon-by-taxon manner, and broadly classified as either a single major transient or a series of repetitive oscillations. Both solitary and oscillatory types of fertilization-induced Ca²⁺ signals are typically propagated as global waves that depend on Ca²⁺ release from the endoplasmic reticulum in response to increased concentrations of inositol 1,4,5-trisphosphate (IP₃). Thus, for taxa where relevant data are available, upstream pathways that elevate intraoocytic IP3 levels during fertilization are described, while other less-common modes of producing Ca²⁺ transients are also examined. In addition, the importance of fertilization-induced Ca²⁺ signals for activating development is underscored by noting some major downstream effects of these signals in various animals. © 2013 Wiley Periodicals, Inc.

  4. Risk factors for calcium carbonate urolithiasis in goats.

    PubMed

    Nwaokorie, Eugene E; Osborne, Carl A; Lulich, Jody P; Fletcher, Thomas F; Ulrich, Lisa K; Koehler, Lori A; Buettner, Michelle T

    2015-08-01

    To identify demographic or signalment factors associated with calcium carbonate urolith formation in goats. Retrospective case series and case-control study. 354 goats with calcium carbonate uroliths (case animals) and 16,366 goats without urinary tract disease (control animals). Medical records of the Minnesota Urolith Center were reviewed to identify case goats for which samples were submitted between January 1, 1984, and December 31, 2012. Control goats evaluated at US veterinary teaching hospitals in the same time period were identified by searching Veterinary Medical Database records. Age, breed, sex, reproductive status, geographic location, season, and anatomic location of collected uroliths were analyzed to identify risk or protective factors associated with calcium carbonate urolithiasis. Nigerian dwarf goats had higher odds of developing calcium carbonate uroliths than did Pygmy goats (reference group). Several breeds had lower odds of this finding, compared with Pygmy goats; odds were lowest for mixed, Anglo-Nubian, and Toggenburg breeds. Breeds of African origin (Pygmy, Nigerian Dwarf, and Boer) comprised 146 of 275 (53%) case goats with data available. Goats of African descent had a higher risk of developing calcium carbonate uroliths than did goats of non-African descent (reference group). Males and neutered goats had higher odds of calcium carbonate urolithiasis, compared with females and sexually intact goats, respectively. Age category, geographic location, and season were associated with detection of calcium carbonate uroliths. Goats with calcium carbonate uroliths were typically neutered males, > 1 year of age, and of African descent. This study identified factors associated with calcium carbonate urolithiasis in goats; however, these associations do not allow conclusions regarding cause-and-effect relationships.

  5. Alpha Hemolysin Induces an Increase of Erythrocytes Calcium: A FLIM 2-Photon Phasor Analysis Approach

    PubMed Central

    Sanchez, Susana; Bakás, Laura; Gratton, Enrico; Herlax, Vanesa

    2011-01-01

    α-hemolysin (HlyA) from Escherichia coli is considered as the prototype of a family of toxins called RTX (repeat in toxin), a group of proteins that share genetic and structural features. HlyA is an important virulence factor in E. coli extraintestinal infections, such as meningitis, septicemia and urinary infections. High concentrations of the toxin cause the lysis of several cells such as erythrocytes, granulocytes, monocytes, endothelial and renal epithelial cells of different species. At low concentrations it induces the production of cytokines and apoptosis. Since many of the subcytolytic effects in other cells have been reported to be triggered by the increase of intracellular calcium, we followed the calcium concentration inside the erythrocytes while incubating with sublytic concentrations of HlyA. Calcium concentration was monitored using the calcium indicator Green 1, 2-photon excitation, and fluorescence lifetime imaging microscopy (FLIM). Data were analyzed using the phasor representation. In this report, we present evidence that, at sublytic concentrations, HlyA induces an increase of calcium concentration in rabbit erythrocytes in the first 10 s. Results are discussed in relation to the difficulties of measuring calcium concentrations in erythrocytes where hemoglobin is present, the contribution of the background and the heterogeneity of the response observed in individual cells. PMID:21698153

  6. Paclitaxel Induces Apoptosis in Breast Cancer Cells through Different Calcium—Regulating Mechanisms Depending on External Calcium Conditions

    PubMed Central

    Pan, Zhi; Avila, Andrew; Gollahon, Lauren

    2014-01-01

    Previously, we reported that endoplasmic reticulum calcium stores were a direct target for paclitaxel initiation of apoptosis. Furthermore, the actions of paclitaxel attenuated Bcl-2 resistance to apoptosis through endoplasmic reticulum-mediated calcium release. To better understand the calcium-regulated mechanisms of paclitaxel-induced apoptosis in breast cancer cells, we investigated the role of extracellular calcium, specifically; whether influx of extracellular calcium contributed to and/or was necessary for paclitaxel-induced apoptosis. Our results demonstrated that paclitaxel induced extracellular calcium influx. This mobilization of extracellular calcium contributed to subsequent cytosolic calcium elevation differently, depending on dosage. Under normal extracellular calcium conditions, high dose paclitaxel induced apoptosis-promoting calcium influx, which did not occur in calcium-free conditions. In the absence of extracellular calcium an “Enhanced Calcium Efflux” mechanism in which high dose paclitaxel stimulated calcium efflux immediately, leading to dramatic cytosolic calcium decrease, was observed. In the absence of extracellular calcium, high dose paclitaxel’s stimulatory effects on capacitative calcium entry and apoptosis could not be completely restored. Thus, normal extracellular calcium concentrations are critical for high dose paclitaxel-induced apoptosis. In contrast, low dose paclitaxel mirrored controls, indicating that it occurs independent of extracellular calcium. Thus, extracellular calcium conditions only affect efficacy of high dose paclitaxel-induced apoptosis. PMID:24549172

  7. Intracellular Calcium Mobilization in Response to Ion Channel Regulators via a Calcium-Induced Calcium Release Mechanism

    PubMed Central

    Petrou, Terry; Olsen, Hervør L.; Thrasivoulou, Christopher; Masters, John R.; Ashmore, Jonathan F.

    2017-01-01

    Free intracellular calcium ([Ca2+]i), in addition to being an important second messenger, is a key regulator of many cellular processes including cell membrane potential, proliferation, and apoptosis. In many cases, the mobilization of [Ca2+]i is controlled by intracellular store activation and calcium influx. We have investigated the effect of several ion channel modulators, which have been used to treat a range of human diseases, on [Ca2+]i release, by ratiometric calcium imaging. We show that six such modulators [amiodarone (Ami), dofetilide, furosemide (Fur), minoxidil (Min), loxapine (Lox), and Nicorandil] initiate release of [Ca2+]i in prostate and breast cancer cell lines, PC3 and MCF7, respectively. Whole-cell currents in PC3 cells were inhibited by the compounds tested in patch-clamp experiments in a concentration-dependent manner. In all cases [Ca2+]i was increased by modulator concentrations comparable to those used clinically. The increase in [Ca2+]i in response to Ami, Fur, Lox, and Min was reduced significantly (P < 0.01) when the external calcium was reduced to nM concentration by chelation with EGTA. The data suggest that many ion channel regulators mobilize [Ca2+]i. We suggest a mechanism whereby calcium-induced calcium release is implicated; such a mechanism may be important for understanding the action of these compounds. PMID:27980039

  8. Hypoxia-Induced Mitogenic Factor Promotes Cardiac Hypertrophy via Calcium-Dependent and Hypoxia-Inducible Factor-1α Mechanisms.

    PubMed

    Kumar, Santosh; Wang, Gang; Liu, Wenjuan; Ding, Wenwen; Dong, Ming; Zheng, Na; Ye, Hongyu; Liu, Jie

    2018-06-11

    HIMF (hypoxia-induced mitogenic factor/found in inflammatory zone 1/resistin like α) is a secretory and cytokine-like protein and serves as a critical stimulator of hypoxia-induced pulmonary hypertension. With a role for HIMF in heart disease unknown, we explored the possible roles for HIMF in cardiac hypertrophy by overexpressing and knocking down HIMF in cardiomyocytes and characterizing HIMF gene ( himf ) knockout mice. We found that HIMF mRNA and protein levels were upregulated in phenylephrine-stimulated cardiomyocyte hypertrophy and our mouse model of transverse aortic constriction-induced cardiac hypertrophy, as well as in human hearts with dilated cardiomyopathy. Furthermore, HIMF overexpression could induce cardiomyocyte hypertrophy, as characterized by elevated protein expression of hypertrophic biomarkers (ANP [atrial natriuretic peptide] and β-MHC [myosin heavy chain-β]) and increased cell-surface area compared with controls. Conversely, HIMF knockdown prevented phenylephrine-induced cardiomyocyte hypertrophy and himf ablation in knockout mice significantly attenuated transverse aortic constriction-induced hypertrophic remodeling and cardiac dysfunction. HIMF overexpression increased the cytosolic Ca 2+ concentration and activated the CaN-NFAT (calcineurin-nuclear factor of activated T cell) and MAPK (mitogen-activated protein kinase) pathways; this effect could be prevented by reducing cytosolic Ca 2+ concentration with L-type Ca 2+ channel blocker nifedipine or inhibiting the CaSR (Ca 2+ sensing receptor) with Calhex 231. Furthermore, HIMF overexpression increased HIF-1α (hypoxia-inducible factor) expression in neonatal rat ventricular myocytes, and HIMF knockout inhibited HIF-1α upregulation in transverse aortic constriction mice. Knockdown of HIF-1α attenuated HIMF-induced cardiomyocyte hypertrophy. In conclusion, HIMF has a critical role in the development of cardiac hypertrophy, and targeting HIMF may represent a potential therapeutic

  9. Memantine Can Reduce Ethanol-Induced Caspase-3 Activity and Apoptosis in H4 Cells by Decreasing Intracellular Calcium.

    PubMed

    Wang, Xiaolong; Chen, Jiajun; Wang, Hongbo; Yu, Hao; Wang, Changliang; You, Jiabin; Wang, Pengfei; Feng, Chunmei; Xu, Guohui; Wu, Xu; Zhao, Rui; Zhang, Guohua

    2017-08-01

    Caspase-3 activation and apoptosis are associated with various neurodegenerative disorders. Calcium activation is an important factor in promoting apoptosis. We, therefore, assessed the role of intracellular calcium in ethanol-induced activation of caspase-3 in H4 human neuroglioma cells and the protective effect of the NMDA receptor antagonist, memantine, on ethanol-induced apoptosis in H4 cells. H4 cells were treated with 100 mM EtOH (in culture medium) for 2 days. For interaction studies, cells were treated with memantine (4 μM), EDTA (1 mM), or BAPTA-AM (10 μM) before treatment with EtOH. Knockdown of the gene encoding the NR1 subunit of the NMDA receptor was performed using RNAi. Apoptosis was detected by Annexin V-FITC/PI staining and flow cytometry. Cell viability was detected using an MTS cell proliferation kit. Fluorescence dual wavelength spectrophotometry was used to determine the intracellular calcium concentration. The levels of NR1, caspase-3, IP3R1, and SERCA1 proteins were detected by western blotting. NR1, IP3R1, and SERCA1 mRNA levels were detected by qPCR. We observed increased expression of NR1, IP3R1, SERCA1, and increased intracellular levels of calcium ions in H4 cells exposed to ethanol. In addition, the calcium chelators, EDTA and BAPTA, and RNAi disruption of the NMDA receptor reduced ethanol-induced caspase-3 activation in H4 cells. Memantine treatment reduced the ethanol-induced increase of intracellular calcium, caspase-3 activation, apoptosis, and the ethanol-induced decrease in cell viability. Our results indicate that ethanol-induced caspase-3 activation and apoptosis are likely to be dependent on cytosolic calcium levels and that they can be reduced by memantine treatment.

  10. Chronic alcohol feeding potentiates hormone-induced calcium signalling in hepatocytes.

    PubMed

    Bartlett, Paula J; Antony, Anil Noronha; Agarwal, Amit; Hilly, Mauricette; Prince, Victoria L; Combettes, Laurent; Hoek, Jan B; Gaspers, Lawrence D

    2017-05-15

    Chronic alcohol consumption causes a spectrum of liver diseases, but the pathogenic mechanisms driving the onset and progression of disease are not clearly defined. We show that chronic alcohol feeding sensitizes rat hepatocytes to Ca 2+ -mobilizing hormones resulting in a leftward shift in the concentration-response relationship and the transition from oscillatory to more sustained and prolonged Ca 2+ increases. Our data demonstrate that alcohol-dependent adaptation in the Ca 2+ signalling pathway occurs at the level of hormone-induced inositol 1,4,5 trisphosphate (IP 3 ) production and does not involve changes in the sensitivity of the IP 3 receptor or size of internal Ca 2+ stores. We suggest that prolonged and aberrant hormone-evoked Ca 2+ increases may stimulate the production of mitochondrial reactive oxygen species and contribute to alcohol-induced hepatocyte injury. ABSTRACT: 'Adaptive' responses of the liver to chronic alcohol consumption may underlie the development of cell and tissue injury. Alcohol administration can perturb multiple signalling pathways including phosphoinositide-dependent cytosolic calcium ([Ca 2+ ] i ) increases, which can adversely affect mitochondrial Ca 2+ levels, reactive oxygen species production and energy metabolism. Our data indicate that chronic alcohol feeding induces a leftward shift in the dose-response for Ca 2+ -mobilizing hormones resulting in more sustained and prolonged [Ca 2+ ] i increases in both cultured hepatocytes and hepatocytes within the intact perfused liver. Ca 2+ increases were initiated at lower hormone concentrations, and intercellular calcium wave propagation rates were faster in alcoholics compared to controls. Acute alcohol treatment (25 mm) completely inhibited hormone-induced calcium increases in control livers, but not after chronic alcohol-feeding, suggesting desensitization to the inhibitory actions of ethanol. Hormone-induced inositol 1,4,5 trisphosphate (IP 3 ) accumulation and phospholipase C

  11. Calcium-induced calcium release in rod photoreceptor terminals boosts synaptic transmission during maintained depolarization

    PubMed Central

    Cadetti, Lucia; Bryson, Eric J.; Ciccone, Cory A.; Rabl, Katalin; Thoreson, Wallace B.

    2008-01-01

    We examined the contribution of calcium-induced calcium release (CICR) to synaptic transmission from rod photoreceptor terminals. Whole-cell recording and confocal calcium imaging experiments were conducted on rods with intact synaptic terminals in a retinal slice preparation from salamander. Low concentrations of ryanodine stimulated calcium increases in rod terminals, consistent with the presence of ryanodine receptors. Application of strong depolarizing steps (−70 to −10 mV) exceeding 200 ms or longer in duration evoked a wave of calcium that spread across the synaptic terminals of voltage-clamped rods. This secondary calcium increase was blocked by high concentrations of ryanodine, indicating it was due to CICR. Ryanodine (50 μM) had no significant effect on rod calcium current (Ica) although it slightly diminished rod light-evoked voltage responses. Bath application of 50 μM ryanodine strongly inhibited light-evoked currents in horizontal cells. Whether applied extracellularly or delivered into the rod cell through the patch pipette, ryanodine (50 μM) also inhibited excitatory post-synaptic currents (EPSCs) evoked in horizontal cells by depolarizing steps applied to rods. Ryanodine caused a preferential reduction in the later portions of EPSCs evoked by depolarizing steps of 200 ms or longer. These results indicate that CICR enhances calcium increases in rod terminals evoked by sustained depolarization, which in turn acts to boost synaptic exocytosis from rods. PMID:16819987

  12. Effects of calcium antagonists on isolated bovine cerebral arteries: inhibition of constriction and calcium-45 uptake induced by potassium or serotonin

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

    Wendling, W.W.; Harakal, C.

    1987-05-01

    The purpose of this study was to determine the mechanisms by which organic calcium channel blockers inhibit cerebral vasoconstriction. Isolated bovine middle cerebral arteries were cut into rings to measure contractility or into strips to measure radioactive calcium (/sup 45/Ca) influx and efflux. Calcium channel blockers (10(-5) M verapamil or 3.3 X 10(-7) M nifedipine) and calcium-deficient solutions all produced near-maximal inhibition of both potassium- and serotonin-induced constriction. In calcium-deficient solutions containing potassium or serotonin, verapamil and nifedipine each blocked subsequent calcium-induced constriction in a competitive manner. Potassium and serotonin significantly increased /sup 45/Ca uptake into cerebral artery strips duringmore » 5 minutes of /sup 45/Ca loading; for potassium /sup 45/Ca uptake increased from 62 to 188 nmol/g, and for serotonin from 65 to 102 nmol/g. Verapamil or nifedipine had no effect on basal /sup 45/Ca uptake but significantly blocked the increase in /sup 45/Ca uptake induced by potassium or serotonin. Potassium, and to a lesser extent serotonin, each induced a brief increase in the rate of /sup 45/Ca efflux into calcium-deficient solutions. Verapamil or nifedipine had no effect on basal or potassium-stimulated /sup 45/Ca efflux. The results demonstrate that verapamil and nifedipine block /sup 45/Ca uptake through both potential-operated (potassium) and receptor-operated (serotonin) channels in bovine middle cerebral arteries.« less

  13. Visualisation of an nsPEF induced calcium wave using the genetically encoded calcium indicator GCaMP in U87 human glioblastoma cells.

    PubMed

    Carr, Lynn; Bardet, Sylvia M; Arnaud-Cormos, Delia; Leveque, Philippe; O'Connor, Rodney P

    2018-02-01

    Cytosolic, synthetic chemical calcium indicators are typically used to visualise the rapid increase in intracellular calcium ion concentration that follows nanosecond pulsed electric field (nsPEF) application. This study looks at the application of genetically encoded calcium indicators (GECIs) to investigate the spatiotemporal nature of nsPEF-induced calcium signals using fluorescent live cell imaging. Calcium responses to 44kV/cm, 10ns pulses were observed in U87-MG cells expressing either a plasma membrane targeted GECI (GCaMP5-G), or one cytosolically expressed (GCaMP6-S), and compared to the response of cells loaded with cytosolic or plasma membrane targeted chemical calcium indicators. Application of 100 pulses, to cells containing plasma membrane targeted indicators, revealed a wave of calcium across the cell initiating at the cathode side. A similar spatial wave was not observed with cytosolic indicators with mobile calcium buffering properties. The speed of the wave was related to pulse application frequency and it was not propagated by calcium induced calcium release. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Calcium mobilization in HeLa cells induced by nitric oxide.

    PubMed

    Huang, Yimei; Zheng, Liqin; Yang, Hongqin; Chen, Jiangxu; Wang, Yuhua; Li, Hui; Xie, Shusen

    2014-01-01

    Nitric oxide (NO) has been proposed to be involved in tumor growth and metastasis. However, the mechanism by which nitric oxide modulates cancer cell growth and metastasis on cellular and molecular level is still not fully understood. This work utilized confocal microscopy and fluorescence microplate reader to investigate the effects of exogenous NO on the mobilization of calcium, which is one of the regulators of cell migration, in HeLa cells. The results show that NO elevates calcium in concentration-dependent manner in HeLa cells. And the elevation of calcium induced by NO is due to calcium influx and calcium release from intracellular calcium stores. Moreover, calcium release from intracellular stores is dominant. Furthermore, calcium release from mitochondria is one of the modulation pathways of NO. These findings would contribute to recognizing the significance of NO in cancer cell proliferation and metastasis. © Wiley Periodicals, Inc.

  15. Spermine selectively inhibits high-conductance, but not low-conductance calcium-induced permeability transition pore.

    PubMed

    Elustondo, Pia A; Negoda, Alexander; Kane, Constance L; Kane, Daniel A; Pavlov, Evgeny V

    2015-02-01

    The permeability transition pore (PTP) is a large channel of the mitochondrial inner membrane, the opening of which is the central event in many types of stress-induced cell death. PTP opening is induced by elevated concentrations of mitochondrial calcium. It has been demonstrated that spermine and other polyamines can delay calcium-induced swelling of isolated mitochondria, suggesting their role as inhibitors of the mitochondrial PTP. Here we further investigated the mechanism by which spermine inhibits the calcium-induced, cyclosporine A (CSA) -sensitive PTP by using three indicators: 1) calcium release from the mitochondria detected with calcium green, 2) mitochondrial membrane depolarization using TMRM, and 3) mitochondrial swelling by measuring light absorbance. We found that despite calcium release and membrane depolarization, indicative of PTP activation, mitochondria underwent only partial swelling in the presence of spermine. This was in striking contrast to the high-amplitude swelling detected in control mitochondria and in mitochondria treated with the PTP inhibitor CSA. We conclude that spermine selectively prevents opening of the high-conductance state, while allowing activation of the lower conductance state of the PTP. We propose that the existence of lower conductance, stress-induced PTP might play an important physiological role, as it is expected to allow the release of toxic levels of calcium, while keeping important molecules (e.g., NAD) within the mitochondrial matrix. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Chronic alcohol feeding potentiates hormone‐induced calcium signalling in hepatocytes

    PubMed Central

    Bartlett, Paula J.; Antony, Anil Noronha; Agarwal, Amit; Hilly, Mauricette; Prince, Victoria L.; Combettes, Laurent; Hoek, Jan B.

    2017-01-01

    Key points Chronic alcohol consumption causes a spectrum of liver diseases, but the pathogenic mechanisms driving the onset and progression of disease are not clearly defined.We show that chronic alcohol feeding sensitizes rat hepatocytes to Ca2+‐mobilizing hormones resulting in a leftward shift in the concentration–response relationship and the transition from oscillatory to more sustained and prolonged Ca2+ increases.Our data demonstrate that alcohol‐dependent adaptation in the Ca2+ signalling pathway occurs at the level of hormone‐induced inositol 1,4,5 trisphosphate (IP3) production and does not involve changes in the sensitivity of the IP3 receptor or size of internal Ca2+ stores.We suggest that prolonged and aberrant hormone‐evoked Ca2+ increases may stimulate the production of mitochondrial reactive oxygen species and contribute to alcohol‐induced hepatocyte injury. Abstract ‘Adaptive’ responses of the liver to chronic alcohol consumption may underlie the development of cell and tissue injury. Alcohol administration can perturb multiple signalling pathways including phosphoinositide‐dependent cytosolic calcium ([Ca2+]i) increases, which can adversely affect mitochondrial Ca2+ levels, reactive oxygen species production and energy metabolism. Our data indicate that chronic alcohol feeding induces a leftward shift in the dose–response for Ca2+‐mobilizing hormones resulting in more sustained and prolonged [Ca2+]i increases in both cultured hepatocytes and hepatocytes within the intact perfused liver. Ca2+ increases were initiated at lower hormone concentrations, and intercellular calcium wave propagation rates were faster in alcoholics compared to controls. Acute alcohol treatment (25 mm) completely inhibited hormone‐induced calcium increases in control livers, but not after chronic alcohol‐feeding, suggesting desensitization to the inhibitory actions of ethanol. Hormone‐induced inositol 1,4,5 trisphosphate (IP3) accumulation and

  17. Hydrostatic Pressure–Induced Release of Stored Calcium in Cultured Rat Optic Nerve Head Astrocytes

    PubMed Central

    Mandal, Amritlal; Delamere, Nicholas A.

    2010-01-01

    Purpose. Elevated intraocular pressure is associated with glaucomatous optic nerve damage. Other investigators have shown functional changes in optic nerve head astrocytes subjected to elevated hydrostatic pressure (HP) for 1 to 5 days. Recently, the authors reported ERK1/2, p90RSK and NHE1 phosphorylation after 2 hours. Here they examine calcium responses at the onset of HP to determine what precedes ERK1/2 phosphorylation. Methods. Cytoplasmic calcium concentration ([Ca2+]i) was measured in cultured rat optic nerve astrocytes loaded with fura-2. The cells were placed in a closed imaging chamber and subjected to an HP increase of 15 mm Hg. Protein phosphorylation was detected by Western blot analysis. Results. The increase of HP caused an immediate slow increase in [Ca2+]i. The response persisted in calcium-free solution and when nickel chloride (4 mM) was added to suppress channel-mediated calcium entry. Previous depletion of the ER calcium stores by cyclopiazonic acid abolished the HP-induced calcium level increase. The HP-induced increase persisted in cells exposed to xestospongin C, an inhibitor of IP3R-mediated calcium release. In contrast, ryanodine receptor (RyR) antagonist ruthenium red (10 μM) or dantrolene (25 μM) inhibited the HP-induced calcium increase. The HP-induced calcium increase was abolished when ryanodine-sensitive calcium stores were pre-depleted with caffeine (3 mM). HP caused ERK1/2 phosphorylation. The magnitude of the ERK1/2 phosphorylation response was reduced by ruthenium red and dantrolene. Conclusions. Increasing HP causes calcium release from a ryanodine-sensitive cytoplasmic store and subsequent ERK1/2 activation. Calcium store release appears to be a required early step in the initial astrocyte response to an HP increase. PMID:20071675

  18. Heterogeneity of the calcium-induced permeability transition in isolated non-synaptic brain mitochondria.

    PubMed

    Kristián, Tibor; Weatherby, Tina M; Bates, Timothy E; Fiskum, Gary

    2002-12-01

    Calcium overload of neural cell mitochondria plays a key role in excitotoxic and ischemic brain injury. This study tested the hypothesis that brain mitochondria consist of subpopulations with differential sensitivity to calcium-induced inner membrane permeability transition, and that this sensitivity is greatly reduced by physiological levels of adenine nucleotides. Isolated non-synaptosomal rat brain mitochondria were incubated in a potassium-based medium in the absence or presence of ATP or ADP. Measurements were made of medium and intramitochondrial free calcium, light scattering, mitochondrial ultrastructure, and the elemental composition of electron-opaque deposits within mitochondria treated with calcium. In the absence of adenine nucleotides, calcium induced a partial decrease in light scattering, accompanied by three distinct ultrastructural morphologies, including large-amplitude swelling, matrix vacuolization and a normal appearance. In the presence of ATP or ADP the mitochondrial calcium uptake capacity was greatly enhanced and calcium induced an increase rather than a decrease in mitochondrial light scattering. Approximately 10% of the mitochondria appeared damaged and the rest contained electron-dense precipitates that contained calcium, as determined by electron-energy loss spectroscopy. These results indicate that brain mitochondria are heterogeneous in their response to calcium. In the absence of adenine nucleotides, approximately 20% of the mitochondrial population exhibit morphological alterations consistent with activation of the permeability transition, but less than 10% exhibit evidence of osmotic swelling and membrane disruption in the presence of ATP or ADP.

  19. Prolonged exposure to 1,25(OH)2D3 and high ionized calcium induces FGF-23 production in intestinal epithelium-like Caco-2 monolayer: A local negative feedback for preventing excessive calcium transport.

    PubMed

    Rodrat, Mayuree; Wongdee, Kannikar; Panupinthu, Nattapon; Thongbunchoo, Jirawan; Teerapornpuntakit, Jarinthorn; Krishnamra, Nateetip; Charoenphandhu, Narattaphol

    2018-02-15

    Overdose of oral calcium supplement and excessive intestinal calcium absorption can contribute pathophysiological conditions, e.g., nephrolithiasis, vascular calcification, dementia, and cardiovascular accident. Since our previous investigation has indicated that fibroblast growth factor (FGF)-23 could abolish the 1,25-dihydroxyvitamin D 3 [1,25(OH) 2 D 3 ]-enhanced calcium absorption, we further hypothesized that FGF-23 produced locally in the enterocytes might be part of a local negative feedback loop to regulate calcium absorption. Herein, 1,25(OH) 2 D 3 was found to enhance the transcellular calcium transport across the epithelium-like Caco-2 monolayer, and this stimulatory effect was diminished by preceding prolonged exposure to high-dose 1,25(OH) 2 D 3 or high concentration of apical ionized calcium. Pretreatment with a neutralizing antibody for FGF-23 prevented this negative feedback regulation of calcium hyperabsorption induced by 1,25(OH) 2 D 3 . FGF-23 exposure completely abolished the 1,25(OH) 2 D 3 -enhanced calcium transport. Western blot analysis revealed that FGF-23 expression was upregulated in a dose-dependent manner by 1,25(OH) 2 D 3 or apical calcium exposure. Finally, calcium-sensing receptor (CaSR) inhibitors were found to prevent the apical calcium-induced suppression of calcium transport. In conclusion, prolonged exposure to high apical calcium and calcium hyperabsorption were sensed by CaSR, which, in turn, increased FGF-23 expression to suppress calcium transport. This local negative feedback loop can help prevent unnecessary calcium uptake and its detrimental consequences. Copyright © 2018 Elsevier Inc. All rights reserved.

  20. Modification of caffeine-induced injury in Ca2+-free perfused rat hearts. Relationship to the calcium paradox.

    PubMed Central

    Vander Heide, R. S.; Altschuld, R. A.; Lamka, K. G.; Ganote, C. E.

    1986-01-01

    The pathogenesis of the calcium paradox has not been established. In calcium-free perfused hearts, caffeine, which releases calcium from the sarcoplasmic reticulum, causes severe myocardial injury, with creatine kinase (CK) release and contraction band necrosis similar in many respects to the calcium paradox. It has been postulated that contracture, initiated by a small rise in intracellular calcium, may cause sarcolemmal injury in both the calcium paradox and caffeine-induced myocardial injury. The present study was initiated to determine whether interventions which modulate caffeine-induced contracture will also correspondingly alter cellular injury. The effects of caffeine dose, procaine, extended calcium-free perfusion, elevated potassium, temperature, and increasing intracellular sodium on caffeine-induced contracture were examined in Langendorff-perfused adult rat hearts. Caffeine-induced contracture at 22 C increased over a dose range of 5-40 mM caffeine. Procaine, which inhibits caffeine-induced calcium release at doses between 5 and 20 mM, progressively reduced contracture caused by addition of 20 mM caffeine at 22 C. Hearts perfused with calcium-free solution containing 16 mM K+ showed a reduction in caffeine-induced contracture. Extended calcium-free perfusion (20 minutes) at temperatures from 18 to 37 C resulted in a progressive reduction of caffeine-induced contracture. Each of these interventions was also found to inhibit caffeine-induced injury at 37 C. Low temperature was found to have complex effects. Hypothermia enhanced caffeine contractures but also protected hearts from cell separations and CK release. Increasing intracellular sodium was found to enhance caffeine-induced contracture at 37 C. There was a direct correlation between measured intracellular sodium levels and the magnitude and duration of caffeine-induced contracture. These results demonstrate a direct correlation between the magnitude of contracture and myocardial injury in calcium

  1. Angiotensin II induces calcium/calcineurin signaling and podocyte injury by downregulating microRNA-30 family members.

    PubMed

    Zhao, Yue; Wu, Junnan; Zhang, Mingchao; Zhou, Minlin; Xu, Feng; Zhu, Xiaodong; Zhou, Xianguang; Lang, Yue; Yang, Fan; Yun, Shifeng; Shi, Shaolin; Liu, Zhihong

    2017-08-01

    Angiotensin II (AngII) is capable of inducing calcium/calcineurin signaling and podocyte injury; however, the precise underlying mechanism is not well understood. Because we have previously demonstrated that microRNA-30s (miR-30s) inhibit calcium/calcineurin signaling in podocytes, we hypothesize that AngII may induce podocyte injury by downregulating miR-30s and thereby activating calcium/calcineurin signaling. To test this hypothesis, we used an AngII-induced podocyte injury mouse model. The mice were treated with AngII via infusion for 28 days, which resulted in hypertension, albuminuria, and glomerular damage. AngII treatment also resulted in a significant reduction of miR-30s and upregulation of calcium/calcineurin signaling components, including TRPC6, PPP3CA, PPP3CB, PPP3R1, and NFATC3, which are the known targets of miR-30s in podocytes. The delivery of miR-30a-expressing lentivirus to the podocytes on day 14 of the infusion ameliorated the AngII-induced podocyte and glomerular injury and attenuated the upregulation of the calcium/calcineurin signaling components. Similarly, treatment with losartan, which is an AngII receptor blocker, also prevented AngII-induced podocyte injury and calcium/calcineurin signaling activation. Notably, losartan was found to sustain miR-30 levels during AngII treatment both in vivo and in vitro. In conclusion, the effect of AngII on podocytes is in part mediated by miR-30s through calcium/calcineurin signaling, a novel mechanism underlying AngII-induced podocyte injury. • AngII infusion resulted in downregulation of miR-30s in podocytes. • Exogenous miR-30a delivery mitigated the glomerular and podocyte injuries induced by AngII. • Both miR-30a and losartan prevented AngII-induced activation of calcium-calcineurin signaling.

  2. Insulin-Like Growth Factor Binding Proteins Increase Intracellular Calcium Levels in Two Different Cell Lines

    PubMed Central

    Seurin, Danielle; Lombet, Alain; Babajko, Sylvie; Godeau, François; Ricort, Jean-Marc

    2013-01-01

    Background Insulin-like growth factor binding proteins (IGFBPs) are six related secreted proteins that share IGF-dependent and -independent functions. If the former functions begin to be well described, the latter are somewhat more difficult to investigate and to characterize. At the cellular level, IGFBPs were shown to modulate numerous processes including cell growth, differentiation and apoptosis. However, the molecular mechanisms implicated remain largely unknown. We previously demonstrated that IGFBP-3, but not IGFBP-1 or IGFBP-5, increase intracellular calcium concentration in MCF-7 cells (Ricort J-M et al. (2002) FEBS lett 527: 293–297). Methodology/Principal Findings We perform a global analysis in which we studied, by two different approaches, the binding of each IGFBP isoform (i.e., IGFBP-1 to -6) to the surface of two different cellular models, MCF-7 breast adenocarcinoma cells and C2 myoblast proliferative cells, as well as the IGFBP-induced increase of intracellular calcium concentration. Using both confocal fluorescence microscopy and flow cytometry analysis, we showed that all IGFBPs bind to MCF-7 cell surface. By contrast, only four IGFBPs can bind to C2 cell surface since neither IGFBP-2 nor IGFBP-4 were detected. Among the six IGFBPs tested, only IGFBP-1 did not increased intracellular calcium concentration whatever the cellular model studied. By contrast, IGFBP-2, -3, -4 and -6, in MCF-7 cells, and IGFBP-3, -5 and -6, in C2 proliferative cells, induce a rapid and transient increase in intracellular free calcium concentration. Moreover, IGFBP-2 and -3 (in MCF-7 cells) and IGFBP-5 (in C2 cells) increase intracellular free calcium concentration by a pertussis toxin sensitive signaling pathway. Conclusions Our results demonstrate that IGFBPs are able to bind to cell surface and increase intracellular calcium concentration. By characterizing the IGFBPs-induced cell responses and intracellular couplings, we highlight the cellular specificity and

  3. Demographic, dietary, and urinary factors and 24-h urinary calcium excretion.

    PubMed

    Taylor, Eric N; Curhan, Gary C

    2009-12-01

    Higher urinary calcium is a risk factor for nephrolithiasis. This study delineated associations between demographic, dietary, and urinary factors and 24-h urinary calcium. Cross-sectional studies were conducted of 2201 stone formers (SF) and 1167 nonstone formers (NSF) in the Health Professionals Follow-up Study (men) and Nurses' Health Studies I and II (older and younger women). Median urinary calcium was 182 mg/d in men, 182 mg/d in older women, and 192 mg/d in younger women. Compared with NSF, urinary calcium as a fraction of calcium intake was 33 to 38% higher in SF (P values < or =0.01). In regression analyses, participants were combined because associations with urinary calcium were similar in each cohort and in SF and NSF. After multivariate adjustment, participants in the highest quartile of calcium intake excreted 18 mg/d more urinary calcium than those in the lowest (P trend =0.01). Caffeine and family history of nephrolithiasis were positively associated, whereas urinary potassium, thiazides, gout, and age were inversely associated, with urinary calcium. After multivariate adjustment, participants in the highest quartiles of urinary magnesium, sodium, sulfate, citrate, phosphorus, and volume excreted 71 mg/d, 37 mg/d, 44 mg/d, 61 mg/d, 37 mg/d, and 24 mg/d more urinary calcium, respectively, than participants in the lowest (P values trend < or =0.01). Intestinal calcium absorption and/or negative calcium balance is greater in SF than NSF. Higher calcium intakes at levels typically observed in free-living individuals are associated with only small increases in urinary calcium.

  4. Demographic, Dietary, and Urinary Factors and 24-h Urinary Calcium Excretion

    PubMed Central

    Curhan, Gary C.

    2009-01-01

    Background and objectives: Higher urinary calcium is a risk factor for nephrolithiasis. This study delineated associations between demographic, dietary, and urinary factors and 24-h urinary calcium. Design, setting, participants, & measurements: Cross-sectional studies were conducted of 2201 stone formers (SF) and 1167 nonstone formers (NSF) in the Health Professionals Follow-up Study (men) and Nurses' Health Studies I and II (older and younger women). Results: Median urinary calcium was 182 mg/d in men, 182 mg/d in older women, and 192 mg/d in younger women. Compared with NSF, urinary calcium as a fraction of calcium intake was 33 to 38% higher in SF (P values ≤0.01). In regression analyses, participants were combined because associations with urinary calcium were similar in each cohort and in SF and NSF. After multivariate adjustment, participants in the highest quartile of calcium intake excreted 18 mg/d more urinary calcium than those in the lowest (P trend =0.01). Caffeine and family history of nephrolithiasis were positively associated, whereas urinary potassium, thiazides, gout, and age were inversely associated, with urinary calcium. After multivariate adjustment, participants in the highest quartiles of urinary magnesium, sodium, sulfate, citrate, phosphorus, and volume excreted 71 mg/d, 37 mg/d, 44 mg/d, 61 mg/d, 37 mg/d, and 24 mg/d more urinary calcium, respectively, than participants in the lowest (P values trend ≤0.01). Conclusions: Intestinal calcium absorption and/or negative calcium balance is greater in SF than NSF. Higher calcium intakes at levels typically observed in free-living individuals are associated with only small increases in urinary calcium. PMID:19820135

  5. Usefulness of cardiotoxicity assessment using calcium transient in human induced pluripotent stem cell-derived cardiomyocytes.

    PubMed

    Watanabe, Hitoshi; Honda, Yayoi; Deguchi, Jiro; Yamada, Toru; Bando, Kiyoko

    2017-01-01

    Monitoring dramatic changes in intracellular calcium ion levels during cardiac contraction and relaxation, known as calcium transient, in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) would be an attractive strategy for assessing compounds on cardiac contractility. In addition, as arrhythmogenic compounds are known to induce characteristic waveform changes in hiPSC-CMs, it is expected that calcium transient would allow evaluation of not only compound-induced effects on cardiac contractility, but also compound arrhythmogenic potential. Using a combination of calcium transient in hiPSC-CMs and a fast kinetic fluorescence imaging detection system, we examined in this study changes in calcium transient waveforms induced by a series of 17 compounds that include positive/negative inotropic agents as well as cardiac ion channel activators/inhibitors. We found that all positive inotropic compounds induced an increase in peak frequency and/or peak amplitude. The effects of a negative inotropic compound could clearly be detected in the presence of a β-adrenergic receptor agonist. Furthermore, most arrhythmogenic compounds raised the ratio of peak decay time to peak rise time (D/R ratio) in calcium transient waveforms. Compound concentrations at which these parameters exceeded cutoff values correlated well with systemic exposure levels at which arrhythmias were reported to be evoked. In conclusion, we believe that peak analysis of calcium transient and determination of D/R ratio are reliable methods for assessing compounds' cardiac contractility and arrhythmogenic potential, respectively. Using these approaches would allow selection of compounds with low cardiotoxic potential at the early stage of drug discovery.

  6. Isoflurane-Induced Caspase-3 Activation Is Dependent on Cytosolic Calcium and Can Be Attenuated by Memantine

    PubMed Central

    Zhang, Guohua; Dong, Yuanlin; Zhang, Bin; Ichinose, Fumito; Wu, Xu; Culley, Deborah J.; Crosby, Gregory

    2008-01-01

    Increasing evidence indicates that caspase activation and apoptosis are associated with a variety of neurodegenerative disorders, including Alzheimer's disease. We reported that anesthetic isoflurane can induce apoptosis, alter processing of the amyloid precursor protein (APP), and increase amyloid-β protein (Aβ) generation. However, the mechanism by which isoflurane induces apoptosis is primarily unknown. We therefore set out to assess effects of extracellular calcium concentration on isoflurane-induced caspase-3 activation in H4 human neuroglioma cells stably transfected to express human full-length APP (H4-APP cells). In addition, we tested effects of RNA interference (RNAi) silencing of IP3 receptor, NMDA receptor, and endoplasmic reticulum (ER) calcium pump, sacro-/ER calcium ATPase (SERCA1). Finally, we examined the effects of the NMDA receptor partial antagonist, memantine, in H4-APP cells and brain tissue of naive mice. EDTA (10 mm), BAPTA (10 μm), and RNAi silencing of IP3 receptor, NMDA receptor, or SERCA1 attenuated capase-3 activation. Memantine (4 μm) inhibited isoflurane-induced elevations in cytosolic calcium levels and attenuated isoflurane-induced caspase-3 activation, apoptosis, and cell viability. Memantine (20 mg/kg, i.p.) reduced isoflurane-induced caspase-3 activation in brain tissue of naive mice. These results suggest that disruption of calcium homeostasis underlies isoflurane-induced caspase activation and apoptosis. We also show for the first time that the NMDA receptor partial antagonist, memantine, can prevent isoflurane-induced caspase-3 activation and apoptosis in vivo and in vitro. These findings, indicating that isoflurane-induced caspase activation and apoptosis are dependent on cytosolic calcium levels, should facilitate the provision of safer anesthesia care, especially for Alzheimer's disease and elderly patients. PMID:18434534

  7. Platelet-independent adhesion of calcium-loaded erythrocytes to von Willebrand factor

    PubMed Central

    Bierings, Ruben; Meems, Henriet; Mul, Frederik P. J.; Geerts, Dirk; Vlaar, Alexander P. J.; Voorberg, Jan; Hordijk, Peter L.

    2017-01-01

    Adhesion of erythrocytes to endothelial cells lining the vascular wall can cause vaso-occlusive events that impair blood flow which in turn may result in ischemia and tissue damage. Adhesion of erythrocytes to vascular endothelial cells has been described in multiple hemolytic disorders, especially in sickle cell disease, but the adhesion of normal erythrocytes to endothelial cells has hardly been described. It was shown that calcium-loaded erythrocytes can adhere to endothelial cells. Because sickle erythrocyte adhesion to ECs can be enhanced by ultra-large von Willebrand factor multimers, we investigated whether calcium loading of erythrocytes could promote binding to endothelial cells via ultra-large von Willebrand factor multimers. We used (immunofluorescent) live-cell imaging of washed erythrocytes perfused over primary endothelial cells at venular flow rate. Using this approach, we show that calcium-loaded erythrocytes strongly adhere to histamine-stimulated primary human endothelial cells. This adhesion is mediated by ultra-large von Willebrand factor multimers. Von Willebrand factor knockdown or ADAMTS13 cleavage abolished the binding of erythrocytes to activated endothelial cells under flow. Platelet depletion did not interfere with erythrocyte binding to von Willebrand factor. Our results reveal platelet-independent adhesion of calcium-loaded erythrocytes to endothelium-derived von Willebrand factor. Erythrocyte adhesion to von Willebrand factor may be particularly relevant for venous thrombosis, which is characterized by the formation of erythrocyte-rich thrombi. PMID:28249049

  8. Importance of mitochondrial calcium uniporter in high glucose-induced endothelial cell dysfunction.

    PubMed

    Chen, Wei; Yang, Jie; Chen, Shuhua; Xiang, Hong; Liu, Hengdao; Lin, Dan; Zhao, Shaoli; Peng, Hui; Chen, Pan; Chen, Alex F; Lu, Hongwei

    2017-11-01

    Mitochondrial Ca 2+ overload is implicated in hyperglycaemia-induced endothelial cell dysfunction, but the key molecular events responsible remain unclear. We examined the involvement of mitochondrial calcium uniporter, which mediates mitochondrial Ca 2+ uptake, in endothelial cell dysfunction resulting from high-glucose treatment. Human umbilical vein endothelial cells were exposed to various glucose concentrations and to high glucose (30 mM) following mitochondrial calcium uniporter inhibition or activation with ruthenium red and spermine, respectively. Subsequently, mitochondrial calcium uniporter and mitochondrial calcium uniporter regulator 1 messenger RNA and protein expression was measured by real-time polymerase chain reaction and western blotting. Ca 2+ concentrations were analysed by laser confocal microscopy, and cytoplasmic and mitochondrial oxidative stress was detected using 2',7'-dichlorofluorescein diacetate and MitoSOX Red, respectively. Apoptosis was assessed by annexin V-fluorescein isothiocyanate/propidium iodide staining, and a wound-healing assay was performed using an in vitro model. High glucose markedly upregulated mitochondrial calcium uniporter and mitochondrial calcium uniporter regulator 1 messenger RNA expression, as well as protein production, in a dose- and time-dependent manner with a maximum effect demonstrated at 72 h and 30 mM glucose concentration. Moreover, high-glucose treatment significantly raised both mitochondrial and cytoplasmic Ca 2+ and reactive oxygen species levels, increased apoptosis and compromised wound healing (all p < 0.05). These effects were enhanced by spermine and completely negated by ruthenium red, which are known to activate and inhibit mitochondrial calcium uniporter, respectively. Mitochondrial calcium uniporter plays an important role in hyperglycaemia-induced endothelial cell dysfunction and may constitute a therapeutic target to reduce vascular complications in diabetes.

  9. Putting out the fire: what terminates calcium-induced calcium release in cardiac muscle?

    PubMed

    Stern, Michael D; Cheng, Heping

    2004-06-01

    The majority of contractile calcium in cardiac muscle is released from stores in the sarcoplasmic reticulum (SR), by a process of calcium-induced calcium release (CICR) through ryanodine receptors. Because CICR is intrinsically self-reinforcing, the stability of and graded regulation of cardiac EC coupling appear paradoxical. It is now well established that this gradation results from the stochastic recruitment of varying numbers of elementary local release events, which may themselves be regenerative, and which can be directly observed as calcium sparks. Ryanodine receptors (RyRs) are clustered in dense lattices, and most calcium sparks are now believed to involve activation of multiple RyRs. This implies that local CICR is regenerative, requiring a mechanism to terminate it. It was initially assumed that this mechanism was inactivation of the RyR, but during the decade since the discovery of sparks, no sufficiently strong inactivation mechanism has been demonstrated in vitro and all empirically determined gating schemes for the RyR give unstable EC coupling in Monte Carlo simulations. We consider here possible release termination mechanisms. Stochastic attrition is the spontaneous decay of active clusters due to random channel closure; calculations show that it is much too slow unless assisted by another process. Calcium-dependent RyR inactivation involving third-party proteins remains a viable but speculative mechanism; current candidates include calmodulin and sorcin. Local depletion of SR release terminal calcium could terminate release, however calculations and measurements leave it uncertain whether a sufficient diffusion resistance exists within the SR to sustain such depletion. Depletion could be assisted by dependence of RyR activity on SR lumenal [Ca(2+)]. There is substantial evidence for such lumenal activation, but it is not clear if it is a strong enough effect to account for the robust termination of sparks. The existence of direct interactions

  10. Hyperuricemia induces endothelial dysfunction via mitochondrial Na+/Ca2+ exchanger-mediated mitochondrial calcium overload.

    PubMed

    Hong, Quan; Qi, Ka; Feng, Zhe; Huang, Zhiyong; Cui, Shaoyuan; Wang, Liyuan; Fu, Bo; Ding, Rui; Yang, Jurong; Chen, Xiangmei; Wu, Di

    2012-05-01

    Uric acid (UA) has proven to be a causal agent in endothelial dysfunction in which ROS production plays an important role. Calcium overload in mitochondria can promote the mitochondrial production of ROS. We hypothesize that calcium transduction in mitochondria contributes to UA-induced endothelial dysfunction. We first demonstrated that high concentrations of UA cause endothelial dysfunction, marked by a reduction in eNOS protein expression and NO release in vitro. We further found that a high concentration of UA increased levels of [Ca2+]mito, total intracellular ROS, H2O2, and mitochondrial O2·-, and Δψmito but not the [Ca2+]cyt level. When the mitochondrial calcium channels NCXmito and MCU were blocked by CGP-37157 and Ru360, respectively, the UA-induced increases in the levels of [Ca2+]mito and total intracellular ROS were significantly reduced. Mitochondrial levels of O2·- and Δψmito were reduced by inhibition of NCXmito but not of MCU. Moreover, inhibition of NCXmito, but not of MCU, blocked the UA-induced reductions in eNOS protein expression and NO release. The increased generation of mitochondrial O2·- induced by a high concentration of UA is triggered by mitochondrial calcium overload and ultimately leads to endothelial dysfunction. In this process, the activation of NCXmito is the major cause of the influx of calcium into mitochondria. Our results provide a new pathophysiological mechanism for UA-induced endothelial dysfunction and may offer a new therapeutic target for clinicians. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Image-based Modeling of Biofilm-induced Calcium Carbonate Precipitation

    NASA Astrophysics Data System (ADS)

    Connolly, J. M.; Rothman, A.; Jackson, B.; Klapper, I.; Cunningham, A. B.; Gerlach, R.

    2013-12-01

    Pore scale biological processes in the subsurface environment are important to understand in relation to many engineering applications including environmental contaminant remediation, geologic carbon sequestration, and petroleum production. Specifically, biofilm induced calcium carbonate precipitation has been identified as an attractive option to reduce permeability in a lasting way in the subsurface. This technology may be able to replace typical cement-based grouting in some circumstances; however, pore-scale processes must be better understood for it to be applied in a controlled manor. The work presented will focus on efforts to observe biofilm growth and ureolysis-induced mineral precipitation in micro-fabricated flow cells combined with finite element modelling as a tool to predict local chemical gradients of interest (see figure). We have been able to observe this phenomenon over time using a novel model organism that is able to hydrolyse urea and express a fluorescent protein allowing for non-invasive observation over time with confocal microscopy. The results of this study show the likely existence of a wide range of local saturation indices even in a small (1 cm length scale) experimental system. Interestingly, the locations of high predicted index do not correspond to the locations of higher precipitation density, highlighting the need for further understanding. Figure 1 - A micro-fabricated flow cell containing biofilm-induced calcium carbonate precipitation. (A) Experimental results: Active biofilm is in green and dark circles are calcium carbonate crystals. Note the channeling behavior in the top of the image, leaving a large hydraulically inactive area in the biofilm mass. (B) Finite element model: The prediction of relative saturation of calcium carbonate (as calcite). Fluid enters the system at a low saturation state (blue) but areas of high supersaturation (red) are predicted within the hydraulically inactive area in the biofilm. If only effluent

  12. Dibenzoylmethane Protects Against CCl4-Induced Acute Liver Injury by Activating Nrf2 via JNK, AMPK, and Calcium Signaling.

    PubMed

    Cao, Mingnan; Wang, Huixia; Guo, Limei; Yang, Simin; Liu, Chun; Khor, Tin Oo; Yu, Siwang; Kong, Ah-Ng

    2017-11-01

    Oxidative stress is an important pathogenic factor in various hepatic diseases. Nuclear factor-erythroid 2-related factor-2 (Nrf2), which coordinates the expression of an array of antioxidant and detoxifying genes, has been proposed as a potential target for prevention and treatment of liver disease. Dibenzoylmethane (DBM) is a minor ingredient in licorice that activates Nrf2 and prevents various cancers and oxidative damage. In the present study, the mechanisms by which DBM activates Nrf2 signaling were delineated, and its protective effect against carbon tetrachloride (CCl 4 )-induced liver injury was examined. DBM potently induced the expression of HO-1 in cells and in the livers of mice, but this induction was diminished in Nrf2-deficient mice and cells. Overexpression of Nrf2 enhanced DBM-induced HO-1 expression, while overexpression of a dominant-negative fragment of Nrf2 inhibited this induction. DBM treatment resulted in dissociation from Keap1 and nuclear translocation of Nrf2. Moreover, DBM activated Akt/protein kinase B, mitogen-activated protein kinases, and AMP-activated protein kinase and increased intracellular calcium levels. Inhibition of JNK, AMPK, or intracellular calcium signaling significantly suppressed the induction of HO-1 expression by DBM. Finally, DBM treatment significantly inhibited CCl 4 -induced acute liver injury in wild-type but not in Nrf2-deficient mice. Taken together, our results revealed the mechanisms by which DBM activates Nrf2 and induces HO-1 expression, and provide molecular basis for the design and development of DBM and its derivatives for prevention or treatment of liver diseases by targeting Nrf2.

  13. Glutathione homeostasis as an important and novel factor controlling blossom-end rot development in calcium-deficient tomato fruits.

    PubMed

    Mestre, Teresa C; Garcia-Sanchez, Francisco; Rubio, Francisco; Martinez, Vicente; Rivero, Rosa M

    2012-11-15

    Based on previous results in which oxidative metabolism was suggested as a possible inducer of blossom-end rot (BER), the main questions addressed here were whether calcium deficiency is the main factor that induces BER or whether this physiological disorder a general stress-related phenomenon? Tomato plants were grown under optimal or deficient calcium concentrations. Only the application of 0.1mM calcium resulted in BER induction, although only half of the fruits grown under this treatment had this disorder. Having fruits showing or not showing BER in the same plant and treatment provided us with a powerful tool that we used to investigate whether calcium deficiency operates alongside another mechanism in the induction of BER. Whether or not this other mechanism was the one controlling BER incidence was also investigated. We performed a complete study of the oxidative metabolism in the pericarp of healthy fruits and in the healthy portion of BER-affected fruits. Calcium deficiency led to an induction of NADPH oxidase, superoxide dismutase, dehydro- and monodehydroascorbate reductase, and to an inhibition of catalase, ascorbate peroxidase and glutathione reductase, with a concomitant accumulation of hydrogen peroxide and an increase in lipid peroxidation. While the ascorbate redox state was not affected by calcium deficiency, the glutathione redox state was markedly reduced. We conclude that calcium deficiency fundamentally affected the activity of the ascorbate-glutathione enzymes, with special importance to the inhibition of GR, which lead to a reduction of the glutathione redox state. This could cause the breakdown of cellular homeostasis, the inhibition of other enzymes responsible for H(2)O(2) detoxification, and ultimately an increase of lipid peroxidation. Therefore, BER is defined here as the visual symptom of a massive lipid peroxidation event caused by the breakdown of cellular glutathione homeostasis. Copyright © 2012 Elsevier GmbH. All rights reserved.

  14. Phosphorylation of a NAC Transcription Factor by a Calcium/Calmodulin-Dependent Protein Kinase Regulates Abscisic Acid-Induced Antioxidant Defense in Maize [Phosphorylation of a NAC Transcription Factor by ZmCCaMK Regulates Abscisic Acid-Induced Antioxidant Defense in Maize

    DOE PAGES

    Zhu, Yuan; Yan, Jingwei; Liu, Weijuan; ...

    2016-05-10

    Calcium/calmodulin-dependent protein kinase (CCaMK) has been shown to play an important role in abscisic acid (ABA)-induced antioxidant defense and enhance the tolerance of plants to drought stress. However, its downstream molecular events are poorly understood. Here, we identify a NAC transcription factor, ZmNAC84, in maize, which physically interacts with ZmCCaMK in vitro and in vivo. ZmNAC84 display a partially overlapping expression pattern with ZmCCaMK after ABA treatment and H 2O 2 is required for ABA-induced ZmNAC84 expression. Functional analysis reveals that ZmNAC84 is essential for ABA-induced antioxidant defense in a ZmCCaMK-dependent manner. Furthermore, ZmCCaMK directly phosphorylates S113 of ZmNAC84 inmore » vitro, and S113 is essential for the ABA-induced stimulation of antioxidant defense by ZmCCaMK. Moreover, overexpression of ZmNAC84 in tobacco can improve drought tolerance, and alleviate drought-induced oxidative damage of transgenic plants. These results define a mechanism for ZmCCaMK function in ABA-induced antioxidant defense, where ABA-produced H 2O 2 first induces expression of ZmCCaMK and ZmNAC84 and activates ZmCCaMK, and subsequently the activated ZmCCaMK phosphorylates ZmNAC84 at S113, thereby inducing antioxidant defense by activating downstream genes.« less

  15. Phosphorylation of a NAC Transcription Factor by a Calcium/Calmodulin-Dependent Protein Kinase Regulates Abscisic Acid-Induced Antioxidant Defense in Maize [Phosphorylation of a NAC Transcription Factor by ZmCCaMK Regulates Abscisic Acid-Induced Antioxidant Defense in Maize

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

    Zhu, Yuan; Yan, Jingwei; Liu, Weijuan

    Calcium/calmodulin-dependent protein kinase (CCaMK) has been shown to play an important role in abscisic acid (ABA)-induced antioxidant defense and enhance the tolerance of plants to drought stress. However, its downstream molecular events are poorly understood. Here, we identify a NAC transcription factor, ZmNAC84, in maize, which physically interacts with ZmCCaMK in vitro and in vivo. ZmNAC84 display a partially overlapping expression pattern with ZmCCaMK after ABA treatment and H 2O 2 is required for ABA-induced ZmNAC84 expression. Functional analysis reveals that ZmNAC84 is essential for ABA-induced antioxidant defense in a ZmCCaMK-dependent manner. Furthermore, ZmCCaMK directly phosphorylates S113 of ZmNAC84 inmore » vitro, and S113 is essential for the ABA-induced stimulation of antioxidant defense by ZmCCaMK. Moreover, overexpression of ZmNAC84 in tobacco can improve drought tolerance, and alleviate drought-induced oxidative damage of transgenic plants. These results define a mechanism for ZmCCaMK function in ABA-induced antioxidant defense, where ABA-produced H 2O 2 first induces expression of ZmCCaMK and ZmNAC84 and activates ZmCCaMK, and subsequently the activated ZmCCaMK phosphorylates ZmNAC84 at S113, thereby inducing antioxidant defense by activating downstream genes.« less

  16. The beneficial effect of the sap of Acer mono in an animal with low-calcium diet-induced osteoporosis-like symptoms.

    PubMed

    Lee, Geun-Shik; Byun, Hyuk-Soo; Kim, Man-Hee; Lee, Bo-Mi; Ko, Sang-Hwan; Jung, Eui-Man; Gwak, Ki-Seob; Choi, In-Gyu; Kang, Ha-Young; Jo, Hyun-Jin; Lee, Hak-Ju; Jeung, Eui-Bae

    2008-11-01

    The sap of Acer mono has been called 'bone-benefit-water' in Korea because of its mineral and sugar content. In particular, the calcium concentration of the sap of A. mono is 37.5 times higher than commercial spring water. In the current study, we examined whether A. mono sap could improve or prevent osteoporosis-like symptoms in a mouse model. Male mice (3 weeks old) were fed a low-calcium diet supplemented with 25, 50 or 100 % A. mono sap, commercial spring water or a high calcium-containing solution as a beverage for 7 weeks. There were no differences in weekly weight gain and food intake among all the groups. Mice that were given a low-calcium diet supplemented with commercial spring water developed osteoporosis-like symptoms. To assess the effect of sap on osteoporosis-like symptoms, we examined serum calcium concentration, and femur density and length, and carried out a histological examination. Serum calcium levels were significantly lower in mice that received a low-calcium diet supplemented with commercial spring water (the negative control group), and in the 25 % sap group compared to mice fed a normal diet, but were normal in the 50 and 100 % sap and high-calcium solution groups. Femur density and length were significantly reduced in the negative control and 25 % sap groups. These results indicate that a 50 % sap solution can mitigate osteoporosis-like symptoms induced by a low-calcium diet. We also examined the regulation of expression of calcium-processing genes in the duodenum and kidney. Duodenal TRPV6 and renal calbindin-D9k were up-regulated dose-dependently by sap, and the levels of these factors were higher than those attained in the spring water-treated control. The results demonstrate that the sap of A. mono ameliorates the low bone density induced by a low-calcium diet, most likely by increasing calcium ion absorption.

  17. Potassium Inhibits Dietary Salt-Induced Transforming Growth Factor-β Production

    PubMed Central

    Ying, Wei-Zhong; Aaron, Kristal; Wang, Pei-Xuan; Sanders, Paul W.

    2009-01-01

    Human and animal studies demonstrate an untoward effect of excess dietary NaCl (salt) intake on cardiovascular function and life span. The endothelium in particular augments the production of transforming growth factor (TGF)-β, a fibrogenic growth factor, in response to excess dietary salt intake. This study explored the initiating mechanism that regulates salt-induced endothelial cell production of TGF-β. Male Sprague-Dawley rats were given diets containing different amounts of NaCl and potassium for 4 days. A bioassay for TGF-β demonstrated increased (35.2%) amounts of active TGF-β in the medium of aortic ring segments from rats on the high-salt diet compared with rats maintained on a 0.3% NaCl diet. Inhibition of the large-conductance, calcium-activated potassium channel inhibited dietary salt-induced vascular production of TGF-β but did not affect production of TGF-β by ring segments from rats on the low-salt diet. Immunohistochemical and Western analyses demonstrated the α subunit of the calcium-activated potassium channel in endothelial cells. Increasing medium [K+] inhibited production of dietary salt-induced vascular production levels of total and active TGF-β but did not alter TGF-β production by aortic rings from rats on the 0.3% NaCl diet. Increasing dietary potassium content decreased urinary active TGF-β in animals receiving the high-salt diet but did not change urinary active TGF-β in animals receiving the low-salt diet. The findings demonstrated an interesting interaction between the dietary intake of potassium and excess NaCl and further showed the fundamental role of the endothelial calcium-activated potassium channel in the vascular response to excess salt intake. PMID:19738156

  18. Shock-induced devolatilization of calcium sulfate and implications for K-T extinctions

    NASA Technical Reports Server (NTRS)

    Chen, Guangqing; Tyburczy, James A.; Ahrens, Thomas J.

    1994-01-01

    The devolatilization of calcium sulfate, which is present in the target rock of the Chicxulub, Mexico impact structure, and dispersal in the stratosphere of the resultant sulfuric acid aerosol have been suggested as a possible mechanism for the Cretaceous-Tertiary extinctions. We measured the amount of SO2 produced from two shock-induced devolatilization reactions of calcium sulfate up to 42 GPa in the laboratory. We found both to proceed to a much lower extent than calculated by equilibrium thermodynamic calculations. Reaction products are found to be approx. 10(exp -2) times those calculated for equilibrium. Upon modeling the quantity of sulfur oxides degassed into the atmosphere from shock devolatilization of CaSO4 in the Chicxulub lithographic section, the resulting 9 x 10(exp 16) to 6 x 10(exp 17) g (in sulfur mass) is lower by a factor of 10-100 than previous upper limit estimates, the related environmental stress arising from the resultant global cooling and fallout of acid rain is insufficient to explain the widespread K-T extinctions.

  19. Proteinaceous and oligosaccharidic elicitors induce different calcium signatures in the nucleus of tobacco cells.

    PubMed

    Lecourieux, David; Lamotte, Olivier; Bourque, Stéphane; Wendehenne, David; Mazars, Christian; Ranjeva, Raoul; Pugin, Alain

    2005-12-01

    We previously reported elevated cytosolic calcium levels in tobacco cells in response to elicitors [D. Lecourieux, C. Mazars, N. Pauly, R. Ranjeva, A. Pugin, Analysis and effects of cytosolic free calcium elevations in response to elicitors in Nicotiana plumbaginifolia cells, Plant Cell 14 (2002) 2627-2641]. These data suggested that in response to elicitors, Ca2+, as a second messenger, was involved in both systemic acquired resistance (RSA) and/or hypersensitive response (HR) depending on calcium signature. Here, we used transformed tobacco cells with apoaequorin expressed in the nucleus to monitor changes in free nuclear calcium concentrations ([Ca2+](nuc)) in response to elicitors. Two types of elicitors are compared: proteins leading to necrosis including four elicitins and harpin, and non-necrotic elicitors including flagellin (flg22) and two oligosaccharidic elicitors, namely the oligogalacturonides (OGs) and the beta-1,3-glucan laminarin. Our data indicate that the proteinaceous elicitors induced a pronounced and sustainable [Ca2+](nuc) elevation, relative to the small effects of oligosaccharidic elicitors. This [Ca2+](nuc) elevation, which seems insufficient to induce cell death, is unlikely to result directly from the diffusion of calcium from the cytosol. The [Ca2+](nuc) rise depends on free cytosolic calcium, IP3, and active oxygen species (AOS) but is independent of nitric oxide.

  20. Iron Mediates N-Methyl-d-aspartate Receptor-dependent Stimulation of Calcium-induced Pathways and Hippocampal Synaptic Plasticity*

    PubMed Central

    Muñoz, Pablo; Humeres, Alexis; Elgueta, Claudio; Kirkwood, Alfredo; Hidalgo, Cecilia; Núñez, Marco T.

    2011-01-01

    Iron deficiency hinders hippocampus-dependent learning processes and impairs cognitive performance, but current knowledge on the molecular mechanisms underlying the unique role of iron in neuronal function is sparse. Here, we investigated the participation of iron on calcium signal generation and ERK1/2 stimulation induced by the glutamate agonist N-methyl-d-aspartate (NMDA), and the effects of iron addition/chelation on hippocampal basal synaptic transmission and long-term potentiation (LTP). Addition of NMDA to primary hippocampal cultures elicited persistent calcium signals that required functional NMDA receptors and were independent of calcium influx through L-type calcium channels or α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors; NMDA also promoted ERK1/2 phosphorylation and nuclear translocation. Iron chelation with desferrioxamine or inhibition of ryanodine receptor (RyR)-mediated calcium release with ryanodine-reduced calcium signal duration and prevented NMDA-induced ERK1/2 activation. Iron addition to hippocampal neurons readily increased the intracellular labile iron pool and stimulated reactive oxygen species production; the antioxidant N-acetylcysteine or the hydroxyl radical trapper MCI-186 prevented these responses. Iron addition to primary hippocampal cultures kept in calcium-free medium elicited calcium signals and stimulated ERK1/2 phosphorylation; RyR inhibition abolished these effects. Iron chelation decreased basal synaptic transmission in hippocampal slices, inhibited iron-induced synaptic stimulation, and impaired sustained LTP in hippocampal CA1 neurons induced by strong stimulation. In contrast, iron addition facilitated sustained LTP induction after suboptimal tetanic stimulation. Together, these results suggest that hippocampal neurons require iron to generate RyR-mediated calcium signals after NMDA receptor stimulation, which in turn promotes ERK1/2 activation, an essential step of sustained LTP. PMID:21296883

  1. Endothelin induces two types of contractions of rat uterus: phasic contractions by way of voltage-dependent calcium channels and developing contractions through a second type of calcium channels

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

    Kozuka, M.; Ito, T.; Hirose, S.

    1989-02-28

    Effects of endothelin on nonvascular smooth muscle have been examined using rat uterine horns and two modes of endothelin action have been revealed. Endothelin (0.3 nM) caused rhythmic contractions of isolated uterus in the presence of extracellular calcium. The rhythmic contractions were completely inhibited by calcium channel antagonists. These characteristics of endothelin-induced contractions were very similar to those induced by oxytocin. Binding assays using /sup 125/I-endothelin showed that endothelin and the calcium channel blockers did not compete for the binding sites. However, endothelin was unique in that it caused, in addition to rhythmic contractions, a slowly developing monophasic contraction thatmore » was insensitive to calcium channel blockers. This developing contraction became dominant at higher concentrations of endothelin and was also calcium dependent.« less

  2. Cilnidipine, an L/N-type calcium channel blocker prevents acquisition and expression of ethanol-induced locomotor sensitization in mice.

    PubMed

    Bhutada, Pravinkumar; Mundhada, Yogita; Patil, Jayshree; Rahigude, Anand; Zambare, Krushna; Deshmukh, Prashant; Tanwar, Dhanshree; Jain, Kishor

    2012-04-11

    Several evidences indicated the involvement of L- and N-type calcium channels in behavioral effects of drugs of abuse, including ethanol. Calcium channels are implicated in ethanol-induced behaviors and neurochemical responses. Calcium channel antagonists block the psychostimulants induced behavioral sensitization. Recently, it is demonstrated that L-, N- and T-type calcium channel blockers attenuate the acute locomotor stimulant effects of ethanol. However, no evidence indicated the role of calcium channels in ethanol-induced psychomotor sensitization. Therefore, present study evaluated the influence of cilnidipine, an L/N-type calcium channel blocker on acquisition and expression of ethanol-induced locomotor sensitization. The results revealed that cilnidipine (0.1 and 1.0μg/mouse, i.c.v.) attenuates the expression of sensitization to locomotor stimulant effect of ethanol (2.0g/kg, i.p.), whereas pre- treatment of cilnidipine (0.1 and 1.0μg/mouse, i.c.v.) during development of sensitization blocks acquisition and attenuates expression of sensitization to locomotor stimulant effect of ethanol. Cilnidipine per se did not influence locomotor activity in tested doses. Further, cilnidipine had no influence on effect of ethanol on rotarod performance. These results support the hypothesis that neuroadaptive changes in calcium channels participate in the acquisition and the expression of ethanol-induced locomotor sensitization. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  3. The antidepressant fluoxetine induces necrosis by energy depletion and mitochondrial calcium overload.

    PubMed

    Charles, Emilie; Hammadi, Mehdi; Kischel, Philippe; Delcroix, Vanessa; Demaurex, Nicolas; Castelbou, Cyril; Vacher, Anne-Marie; Devin, Anne; Ducret, Thomas; Nunes, Paula; Vacher, Pierre

    2017-01-10

    Selective Serotonin Reuptake Inhibitor antidepressants, such as fluoxetine (Prozac), have been shown to induce cell death in cancer cells, paving the way for their potential use as cancer therapy. These compounds are able to increase cytosolic calcium concentration ([Ca2+]cyt), but the involved mechanisms and their physiological consequences are still not well understood. Here, we show that fluoxetine induces an increase in [Ca2+]cyt by emptying the endoplasmic reticulum (ER) through the translocon, an ER Ca2+ leakage structure. Our data also show that fluoxetine inhibits oxygen consumption and lowers mitochondrial ATP. This latter is essential for Ca2+ reuptake into the ER, and we postulated therefore that the fluoxetine-induced decrease in mitochondrial ATP production results in the emptying of the ER, leading to capacitative calcium entry. Furthermore, Ca2+ quickly accumulated in the mitochondria, leading to mitochondrial Ca2+ overload and cell death. We found that fluoxetine could induce an early necrosis in human peripheral blood lymphocytes and Jurkat cells, and could also induce late apoptosis, especially in the tumor cell line. These results shed light on fluoxetine-induced cell death and its potential use in cancer treatment.

  4. The antidepressant fluoxetine induces necrosis by energy depletion and mitochondrial calcium overload

    PubMed Central

    Kischel, Philippe; Delcroix, Vanessa; Demaurex, Nicolas; Castelbou, Cyril; Vacher, Anne-Marie; Devin, Anne; Ducret, Thomas; Nunes, Paula; Vacher, Pierre

    2017-01-01

    Selective Serotonin Reuptake Inhibitor antidepressants, such as fluoxetine (Prozac), have been shown to induce cell death in cancer cells, paving the way for their potential use as cancer therapy. These compounds are able to increase cytosolic calcium concentration ([Ca2+]cyt), but the involved mechanisms and their physiological consequences are still not well understood. Here, we show that fluoxetine induces an increase in [Ca2+]cyt by emptying the endoplasmic reticulum (ER) through the translocon, an ER Ca2+ leakage structure. Our data also show that fluoxetine inhibits oxygen consumption and lowers mitochondrial ATP. This latter is essential for Ca2+ reuptake into the ER, and we postulated therefore that the fluoxetine-induced decrease in mitochondrial ATP production results in the emptying of the ER, leading to capacitative calcium entry. Furthermore, Ca2+ quickly accumulated in the mitochondria, leading to mitochondrial Ca2+ overload and cell death. We found that fluoxetine could induce an early necrosis in human peripheral blood lymphocytes and Jurkat cells, and could also induce late apoptosis, especially in the tumor cell line. These results shed light on fluoxetine-induced cell death and its potential use in cancer treatment. PMID:27911858

  5. Protective effect of T-type calcium channel blocker flunarizine on cisplatin-induced death of auditory cells.

    PubMed

    So, Hong-Seob; Park, Channy; Kim, Hyung-Jin; Lee, Jung-Han; Park, Sung-Yeol; Lee, Jai-Hyung; Lee, Zee-Won; Kim, Hyung-Min; Kalinec, Federico; Lim, David J; Park, Raekil

    2005-06-01

    Changes in intracellular Ca2+ level are involved in a number of intracellular events, including triggering of apoptosis. The role of intracellular calcium mobilization in cisplatin-induced hair cell death, however, is still unknown. In this study, the effect of calcium channel blocker flunarizine (Sibelium), which is used to prescribe for vertigo and tinnitus, on cisplatin-induced hair cell death was investigated in a cochlear organ of Corti-derived cell line, HEI-OC1, and the neonatal (P2) rat organ of Corti explant. Cisplatin induced apoptotic cell death showing nuclear fragmentation, DNA ladder, and TUNEL positive in both HEI-OC1 and primary organ of Corti explant. Flunarizine significantly inhibited the cisplatin-induced apoptosis. Unexpectedly, flunarizine increased the intracellular calcium ([Ca2+]i) levels of HEI-OC1. However, the protective effect of flunarizine against cisplatin was not mediated by modulation of intracellular calcium level. Treatment of cisplatin resulted in ROS generation and lipid peroxidation in HEI-OC1. Flunarizine did not attenuate ROS production but inhibited lipid peroxidation and mitochondrial permeability transition in cisplatin-treated cells. This result suggests that the protective mechanism of flunarizine on cisplatin-induced cytotoxicity is associated with direct inhibition of lipid peroxidation and mitochondrial permeability transition.

  6. The Role of Calcium in Osteoporosis

    NASA Technical Reports Server (NTRS)

    Arnaud, C. D.; Sanchez, S. D.

    1991-01-01

    Calcium requirements may vary throughout the lifespan. During the growth years and up to age 25 to 30, it is important to maximize dietary intake of calcium to maintain positive calcium balance and achieve peak bone mass, thereby possibly decreasing the risk of fracture when bone is subsequently lost. Calcium intake need not be greater than 800 mg/day during the relatively short period of time between the end of bone building and the onset of bone loss (30 to 40 years). Starting at age 40 to 50, both men and women lose bone slowly, but women lose bone more rapidly around the menopause and for about 10 years after. Intestinal calcium absorption and the ability to adapt to low calcium diets are impaired in many postmenopausal women and elderly persons owing to a suspected functional or absolute decrease in the ability of the kidney to produce 1,25(OH)2D2. The bones then become more and more a source of calcium to maintain critical extracellular fluid calcium levels. Excessive dietary intake of protein and fiber may induce significant negative calcium balance and thus increase dietary calcium requirements. Generally, the strongest risk factors for osteoporosis are uncontrollable (e.g., sex, age, and race) or less controllable (e.g., disease and medications). However, several factors such as diet, physical activity, cigarette smoking, and alcohol use are lifestyle related and can be modified to help reduce the risk of osteoporosis.

  7. Intracellular sphingosine releases calcium from lysosomes.

    PubMed

    Höglinger, Doris; Haberkant, Per; Aguilera-Romero, Auxiliadora; Riezman, Howard; Porter, Forbes D; Platt, Frances M; Galione, Antony; Schultz, Carsten

    2015-11-27

    To elucidate new functions of sphingosine (Sph), we demonstrate that the spontaneous elevation of intracellular Sph levels via caged Sph leads to a significant and transient calcium release from acidic stores that is independent of sphingosine 1-phosphate, extracellular and ER calcium levels. This photo-induced Sph-driven calcium release requires the two-pore channel 1 (TPC1) residing on endosomes and lysosomes. Further, uncaging of Sph leads to the translocation of the autophagy-relevant transcription factor EB (TFEB) to the nucleus specifically after lysosomal calcium release. We confirm that Sph accumulates in late endosomes and lysosomes of cells derived from Niemann-Pick disease type C (NPC) patients and demonstrate a greatly reduced calcium release upon Sph uncaging. We conclude that sphingosine is a positive regulator of calcium release from acidic stores and that understanding the interplay between Sph homeostasis, calcium signaling and autophagy will be crucial in developing new therapies for lipid storage disorders such as NPC.

  8. SaRNA-mediated activation of TRPV5 reduces renal calcium oxalate deposition in rat via decreasing urinary calcium excretion.

    PubMed

    Zeng, Tao; Duan, Xiaolu; Zhu, Wei; Liu, Yang; Wu, Wenqi; Zeng, Guohua

    2018-06-01

    Hypercalciuria is a main risk factor for kidney stone  formation. TRPV5 is the gatekeeper protein for mediating calcium transport and reabsorption in the kidney. In the present study, we tested the effect of TRPV5 activation with small activating RNA (saRNA), which could induce gene expression by targeting the promoter of the gene, on ethylene glycol (EG)-induced calcium oxalate (CaOx) crystals formation in rat kidney. Five pairs of RNA activation sequences targeting the promoter of rat TRPV5 were designed and synthesized. The synthesized saRNA with the strongest activating effect was selected, and transcellular calcium transportation was tested by Fura-2 analysis. Subsequently, Sprague-Dawley rats were equally divided into three groups and fed with water, 1% EG for 28 days after injecting the negative control saRNA, 1% EG for 28 days after injecting the selected TRPV5-saRNA, respectively. The CaOx crystal formation and the 24-h urine components were assessed. In vitro study, saRNA ds-320 could significantly activate the expression of TRPV5 and transcellular calcium transportation. In vivo study, after 28 days treatment of EG, rats pre-infected with saRNA ds-320 had lower urinary calcium excretion and renal CaOx crystals formation as compared to that pre-infected with negative control saRNA. Activation of TRVP5 with saRNA ds-320 could inhibit EG-induced calcium oxalate crystals formation via promoting urine calcium reabsorption and decreasing urine calcium excretion in rats.

  9. Calcium signals and caspase-12 participated in paraoxon-induced apoptosis in EL4 cells.

    PubMed

    Li, Lan; Cao, Zhiheng; Jia, Pengfei; Wang, Ziren

    2010-04-01

    In order to investigate whether calcium signals participate in paraoxon (POX)-induced apoptosis in EL4 cells, real-time laser scanning confocal microscopy (LSCM) was used to detect Ca(2+) changes during the POX application. Apoptotic rates of EL4 cells and caspase-12 expression were also evaluated. POX (1-10nM) increased intracellular calcium concentration ([Ca(2+)]i) in EL4 cells in a dose-dependent manner at early stage (0-2h) of POX application, and apoptotic rates of EL4 cells after treatment with POX for 16h were also increased in a dose-dependent manner. Pre-treatment with EGTA, heparin or procaine attenuated POX-induced [Ca(2+)]i elevation and apoptosis. Additionally, POX up-regulated caspase-12 expression in a dose-dependent manner, and pre-treatment with EGTA, heparin or procaine significantly inhibited POX-induced increase of caspase-12 expression. Our results suggested that POX induced [Ca(2+)]i elevation in EL4 cells at the early stage of POX-induced apoptosis, which might involve Ca(2+) efflux from the endoplasmic reticulum (ER) and Ca(2+) influx from extracellular medium. Calcium signals and caspase-12 were important upstream messengers in POX-induced apoptosis in EL4 cells. The ER-associated pathway possibly operated in this apoptosis. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  10. Single Low-Dose Radiation Induced Regulation of Keratinocyte Differentiation in Calcium-Induced HaCaT Cells.

    PubMed

    Hahn, Hyung Jin; Youn, Hae Jeong; Cha, Hwa Jun; Kim, Karam; An, Sungkwan; Ahn, Kyu Joong

    2016-08-01

    We are continually exposed to low-dose radiation (LDR) in the range 0.1 Gy from natural sources, medical devices, nuclear energy plants, and other industrial sources of ionizing radiation. There are three models for the biological mechanism of LDR: the linear no-threshold model, the hormetic model, and the threshold model. We used keratinocytes as a model system to investigate the molecular genetic effects of LDR on epidermal cell differentiation. To identify keratinocyte differentiation, we performed western blots using a specific antibody for involucrin, which is a precursor protein of the keratinocyte cornified envelope and a marker for keratinocyte terminal differentiation. We also performed quantitative polymerase chain reaction. We examined whether LDR induces changes in involucrin messenger RNA (mRNA) and protein levels in calcium-induced keratinocyte differentiation. Exposure of HaCaT cells to LDR (0.1 Gy) induced p21 expression. p21 is a key regulator that induces growth arrest and represses stemness, which accelerates keratinocyte differentiation. We correlated involucrin expression with keratinocyte differentiation, and examined the effects of LDR on involucrin levels and keratinocyte development. LDR significantly increased involucrin mRNA and protein levels during calcium-induced keratinocyte differentiation. These studies provide new evidence for the biological role of LDR, and identify the potential to utilize LDR to regulate or induce keratinocyte differentiation.

  11. Single Low-Dose Radiation Induced Regulation of Keratinocyte Differentiation in Calcium-Induced HaCaT Cells

    PubMed Central

    Hahn, Hyung Jin; Youn, Hae Jeong; Cha, Hwa Jun; Kim, Karam; An, Sungkwan

    2016-01-01

    Background We are continually exposed to low-dose radiation (LDR) in the range 0.1 Gy from natural sources, medical devices, nuclear energy plants, and other industrial sources of ionizing radiation. There are three models for the biological mechanism of LDR: the linear no-threshold model, the hormetic model, and the threshold model. Objective We used keratinocytes as a model system to investigate the molecular genetic effects of LDR on epidermal cell differentiation. Methods To identify keratinocyte differentiation, we performed western blots using a specific antibody for involucrin, which is a precursor protein of the keratinocyte cornified envelope and a marker for keratinocyte terminal differentiation. We also performed quantitative polymerase chain reaction. We examined whether LDR induces changes in involucrin messenger RNA (mRNA) and protein levels in calcium-induced keratinocyte differentiation. Results Exposure of HaCaT cells to LDR (0.1 Gy) induced p21 expression. p21 is a key regulator that induces growth arrest and represses stemness, which accelerates keratinocyte differentiation. We correlated involucrin expression with keratinocyte differentiation, and examined the effects of LDR on involucrin levels and keratinocyte development. LDR significantly increased involucrin mRNA and protein levels during calcium-induced keratinocyte differentiation. Conclusion These studies provide new evidence for the biological role of LDR, and identify the potential to utilize LDR to regulate or induce keratinocyte differentiation. PMID:27489424

  12. Relationship of calcium and membrane guanylate cyclase in adrenocorticotropin-induced steroidogenesis.

    PubMed

    Nambi, P; Aiyar, N V; Roberts, A N; Sharma, R K

    1982-07-01

    Chlorpromazine, when incubated with isolated adrenal cells, inhibited the ACTH-stimulated formation of cGMP and corticosterone production. It also inhibited the ACTH-stimulated membrane guanylate cyclase, but did not affect the binding of ACTH to the membrane receptors. cGMP-induced steroidogenesis was not affected by the drug. These data indicate that chlorpromazine interferes with adrenal steroid metabolism at a site between the hormone receptor and guanylate cyclase and also show that guanylate cyclase is composed of separate receptor and catalytic components. Furthermore, based on the premise that chlorpromazine exerts its inhibitory action by blocking the binding of a calcium receptor protein, such as calmodulin, to the receptor-coupled guanylate cyclase, it is proposed that the interaction of calcium, presumably through a calcium-binding protein, is essential for ACTH-dependent guanylate cyclase.

  13. P2X1 Receptor-Mediated Ca2+ Influx Triggered by DA-9801 Potentiates Nerve Growth Factor-Induced Neurite Outgrowth.

    PubMed

    Back, Moon Jung; Lee, Hae Kyung; Lee, Joo Hyun; Fu, Zhicheng; Son, Mi Won; Choi, Sang Zin; Go, Hyo Sang; Yoo, Sungjae; Hwang, Sun Wook; Kim, Dae Kyong

    2016-11-16

    Nerve growth factor (NGF)-induced neuronal regeneration has emerged as a strategy to treat neuronal degeneration-associated disorders. However, direct NGF administration is limited by the occurrence of adverse effects at high doses of NGF. Therefore, development of a therapeutic strategy to promote the NGF trophic effect is required. In view of the lack of understanding of the mechanism for potentiating the NGF effect, this study investigated molecular targets of DA-9801, a well-standardized Dioscorea rhizome extract, which has a promoting effect on NGF. An increase in intracellular calcium ion level was induced by DA-9801, and chelation of extracellular calcium ions with ethylene-bis(oxyethylenenitrilo)tetraacetic acid (EGTA) suppressed the potentiating effect of DA-9801 on NGF-induced neurite outgrowth. In addition, EGTA treatment reduced the DA-9801-induced phosphorylation of extracellular signal-regulated kinase1/2 (ERK1/2), the major mediators of neurite outgrowth. To find which calcium ion-permeable channel contributes to the calcium ion influx induced by DA-9801, we treated PC12 cells with various inhibitors of calcium ion-permeable channels. NF449, a P2X1 receptor selective antagonist, significantly abolished the potentiating effect of DA-9801 on NGF-induced neurite outgrowth and abrogated the DA-9801-induced ERK1/2 phosphorylation. In addition, transfection with siRNA of P2X1 receptor significantly reduced the DA-9801-enhanced neurite outgrowth. In conclusion, calcium ion influx through P2X1 receptor mediated the promoting effect of DA-9801 on NGF-induced neurite outgrowth via ERK1/2 phosphorylation.

  14. High dietary calcium intake does not counteract disuse-induced bone loss

    NASA Astrophysics Data System (ADS)

    Baecker, N.; Boese, A.; Smith, S. M.; Heer, M.

    Reduction of mechanical stress on bone inhibits osteoblast-mediated bone formation, increases osteoclast-mediated bone resorption, and leads to what has been called disuse osteoporosis. Prolonged therapeutic bed rest, immobilization and space flight are common causes of disuse osteoporosis. There are sufficient data supporting the use of calcium in combination with vitamin D in the prevention and treatment of postmenopausal osteoporosis. In our study we examined the potential of high dietary calcium intake as a nutrition therapy for disuse-induced bone loss during head-down bed rest in healthy young men. In 2 identical metabolic ward, head-down bed rest (HDBR) experiments (crossover design), we studied the effect of high dietary calcium intake (2000 mg/d) in comparison to the recommended calcium intake of 1000 mg/d on markers of bone turnover. Experiment A (EA) was a 6-day randomized, controlled HDBR study. Experiment B (EB) was a 14-day randomized, controlled HDBR study. In both experiments, the test subjects stayed under well-controlled environmental conditions in our metabolic ward. Subjects' diets in the relevant study phases (HDBR versus Ambulatory Control) of EA and EB were identical except for the calcium intake. The subjects obtained 2000 mg/d Calcium in EA and 2000 mg/d in EB. Blood was drawn at baseline, before entering the relevant intervention period, on day 5 in study EA, and on days 6, 11 and 14 in study EB. Serum calcium, bone formation markers - Procollagen-I-C-Propeptide (PICP) and bone alkaline phosphatase (bAP) were analyzed in serum. 24h-urine was collected throughout the studies for determination of the excretion of calcium (UCaV) and a bone resorption marker, C-terminal telopeptide of collagen type I (UCTX). In both studies, serum calcium levels were unchanged. PICP tended to decrease in EA (p=0.08). In EB PICP decreased significantly over time (p=0.003) in both the control and HDBR periods, and tended to further decrease in the HDBR period (p

  15. Cameleon calcium indicator reports cytoplasmic calcium dynamics in Arabidopsis guard cells

    NASA Technical Reports Server (NTRS)

    Allen, G. J.; Kwak, J. M.; Chu, S. P.; Llopis, J.; Tsien, R. Y.; Harper, J. F.; Schroeder, J. I.; Evans, M. L. (Principal Investigator)

    1999-01-01

    Cytoplasmic free calcium ([Ca2+]cyt) acts as a stimulus-induced second messenger in plant cells and multiple signal transduction pathways regulate [Ca2+]cyt in stomatal guard cells. Measuring [Ca2+]cyt in guard cells has previously required loading of calcium-sensitive dyes using invasive and technically difficult micro-injection techniques. To circumvent these problems, we have constitutively expressed the pH-independent, green fluorescent protein-based calcium indicator yellow cameleon 2.1 in Arabidopsis thaliana (Miyawaki et al. 1999; Proc. Natl. Acad. Sci. USA 96, 2135-2140). This yellow cameleon calcium indicator was expressed in guard cells and accumulated predominantly in the cytoplasm. Fluorescence ratio imaging of yellow cameleon 2.1 allowed time-dependent measurements of [Ca2+]cyt in Arabidopsis guard cells. Application of extracellular calcium or the hormone abscisic acid (ABA) induced repetitive [Ca2+]cyt transients in guard cells. [Ca2+]cyt changes could be semi-quantitatively determined following correction of the calibration procedure for chloroplast autofluorescence. Extracellular calcium induced repetitive [Ca2+]cyt transients with peak values of up to approximately 1.5 microM, whereas ABA-induced [Ca2+]cyt transients had peak values up to approximately 0.6 microM. These values are similar to stimulus-induced [Ca2+]cyt changes previously reported in plant cells using ratiometric dyes or aequorin. In some guard cells perfused with low extracellular KCl concentrations, spontaneous calcium transients were observed. As yellow cameleon 2.1 was expressed in all guard cells, [Ca2+]cyt was measured independently in the two guard cells of single stomates for the first time. ABA-induced, calcium-induced or spontaneous [Ca2+]cyt increases were not necessarily synchronized in the two guard cells. Overall, these data demonstrate that that GFP-based cameleon calcium indicators are suitable to measure [Ca2+]cyt changes in guard cells and enable the pattern of [Ca

  16. Shock-induced devolatization of calcium sulfate and implications for K-T extinctions

    NASA Technical Reports Server (NTRS)

    Chen, Guangqing; Tyburczy, James A.; Ahrens, Thomas J.

    1993-01-01

    Calcium sulfate devolatization during the impact at Chicxulub, Mexico and dispersal in the stratosphere of the resultant sulfuric acid aerosol have been suggested as a possible mechanism for the Cretaceous-Tertiary extinctions. In this paper, we investigated two shock-induced devolatization reactions of calcium sulfate up to 42 GPa in the laboratory: CaSO4 + SiO2 yields CaSiO3 + SO3(degassed) and CaSO4 yields CaO + SO2(degassed) + 1/2 O2(degassed). We found both to proceed to a much less extent than calculated by equilibrium thermodynamic calculations. Reaction products are found to be 10(exp -2) times those calculated for equilibrium. Consequently our estimate of the amount of sulfur oxides degassed into the atmosphere from shock devolatization of CaS04 in the Chicxulub lithographic section (6x10(exp 15)-2x10(exp 16)g in sulfur mass) is lower by a factor of 70 to 400 than previous estimates; the related environmental stress arising from the resultant global cooling of approximately 4 K and fallout of acid rain does not appear to suffice to explain the widespread K-T extinctions.

  17. Derangement of calcium metabolism in diabetes mellitus: negative outcome from the synergy between impaired bone turnover and intestinal calcium absorption.

    PubMed

    Wongdee, Kannikar; Krishnamra, Nateetip; Charoenphandhu, Narattaphol

    2017-01-01

    Both types 1 and 2 diabetes mellitus (T1DM and T2DM) are associated with profound deterioration of calcium and bone metabolism, partly from impaired intestinal calcium absorption, leading to a reduction in calcium uptake into the body. T1DM is associated with low bone mineral density (BMD) and osteoporosis, whereas the skeletal changes in T2DM are variable, ranging from normal to increased and to decreased BMD. However, both types of DM eventually compromise bone quality through production of advanced glycation end products and misalignment of collagen fibrils (so-called matrix failure), thereby culminating in a reduction of bone strength. The underlying cellular mechanisms (cellular failure) are related to suppression of osteoblast-induced bone formation and bone calcium accretion, as well as to enhancement of osteoclast-induced bone resorption. Several other T2DM-related pathophysiological changes, e.g., osteoblast insulin resistance, impaired productions of osteogenic growth factors (particularly insulin-like growth factor 1 and bone morphogenetic proteins), overproduction of pro-inflammatory cytokines, hyperglycemia, and dyslipidemia, also aggravate diabetic osteopathy. In the kidney, DM and the resultant hyperglycemia lead to calciuresis and hypercalciuria in both humans and rodents. Furthermore, DM causes deranged functions of endocrine factors related to mineral metabolism, e.g., parathyroid hormone, 1,25-dihydroxyvitamin D 3 , and fibroblast growth factor-23. Despite the wealth of information regarding impaired bone remodeling in DM, the long-lasting effects of DM on calcium metabolism in young growing individuals, pregnant women, and neonates born to women with gestational DM have received scant attention, and their underlying mechanisms are almost unknown and worth exploring.

  18. Genetic Ablation of Calcium-independent Phospholipase A2γ (iPLA2γ) Attenuates Calcium-induced Opening of the Mitochondrial Permeability Transition Pore and Resultant Cytochrome c Release*

    PubMed Central

    Moon, Sung Ho; Jenkins, Christopher M.; Kiebish, Michael A.; Sims, Harold F.; Mancuso, David J.; Gross, Richard W.

    2012-01-01

    Herein, we demonstrate that calcium-independent phospholipase A2γ (iPLA2γ) is a critical mechanistic participant in the calcium-induced opening of the mitochondrial permeability transition pore (mPTP). Liver mitochondria from iPLA2γ−/− mice were markedly resistant to calcium-induced swelling in the presence or absence of phosphate in comparison with wild-type littermates. Furthermore, the iPLA2γ enantioselective inhibitor (R)-(E)-6-(bromomethylene)-3-(1-naphthalenyl)-2H-tetrahydropyran-2-one ((R)-BEL) was markedly more potent than (S)-BEL in inhibiting mPTP opening in mitochondria from wild-type liver in comparison with hepatic mitochondria from iPLA2γ−/− mice. Intriguingly, low micromolar concentrations of long chain fatty acyl-CoAs and the non-hydrolyzable thioether analog of palmitoyl-CoA markedly accelerated Ca2+-induced mPTP opening in liver mitochondria from wild-type mice. The addition of l-carnitine enabled the metabolic channeling of acyl-CoA through carnitine palmitoyltransferases (CPT-1/2) and attenuated the palmitoyl-CoA-mediated amplification of calcium-induced mPTP opening. In contrast, mitochondria from iPLA2γ−/− mice were insensitive to fatty acyl-CoA-mediated augmentation of calcium-induced mPTP opening. Moreover, mitochondria from iPLA2γ−/− mouse liver were resistant to Ca2+/t-butyl hydroperoxide-induced mPTP opening in comparison with wild-type littermates. In support of these findings, cytochrome c release from iPLA2γ−/− mitochondria was dramatically decreased in response to calcium in the presence or absence of either t-butyl hydroperoxide or phenylarsine oxide in comparison with wild-type littermates. Collectively, these results identify iPLA2γ as an important mechanistic component of the mPTP, define its downstream products as potent regulators of mPTP opening, and demonstrate the integrated roles of mitochondrial bioenergetics and lipidomic flux in modulating mPTP opening promoting the activation of necrotic and

  19. Neurotoxicity Induced by Bupivacaine via T-Type Calcium Channels in SH-SY5Y Cells

    PubMed Central

    Wen, Xianjie; Xu, Shiyuan; Liu, Hongzhen; Zhang, Quinguo; Liang, Hua; Yang, Chenxiang; Wang, Hanbing

    2013-01-01

    There is concern regarding neurotoxicity induced by the use of local anesthetics. A previous study showed that an overload of intracellular calcium is involved in the neurotoxic effect of some anesthetics. T-type calcium channels, which lower the threshold of action potentials, can regulate the influx of calcium ions. We hypothesized that T-type calcium channels are involved in bupivacaine-induced neurotoxicity. In this study, we first investigated the effects of different concentrations of bupivacaine on SH-SY5Y cell viability, and established a cell injury model with 1 mM bupivacaine. The cell viability of SH-SY5Y cells was measured following treatment with 1 mM bupivacaine and/or different dosages (10, 50, or 100 µM) of NNC 55-0396 dihydrochloride, an antagonist of T-type calcium channels for 24 h. In addition, we monitored the release of lactate dehydrogenase, cytosolic Ca2+ ([Ca2+]i), cell apoptosis and caspase-3 expression. SH-SY5Y cells pretreated with different dosages (10, 50, or 100 µM) of NNC 55-0396 dihydrochloride improved cell viability, reduced lactate dehydrogenase release, inhibited apoptosis, and reduced caspase-3 expression following bupivacaine exposure. However, the protective effect of NNC 55-0396 dihydrochloride plateaued. Overall, our results suggest that T-type calcium channels may be involved in bupivacaine neurotoxicity. However, identification of the specific subtype of T calcium channels involved requires further investigation. PMID:23658789

  20. Protective effects of resveratrol on calcium-induced oxidative stress in rat heart mitochondria.

    PubMed

    Gutiérrez-Pérez, Areli; Cortés-Rojo, Christian; Noriega-Cisneros, Ruth; Calderón-Cortés, Elizabeth; Manzo-Avalos, Salvador; Clemente-Guerrero, Mónica; Godínez-Hernández, Daniel; Boldogh, Istvan; Saavedra-Molina, Alfredo

    2011-04-01

    Trans-resveratrol is a nutraceutical with known antioxidant, anti-inflammatory, cardioprotective, and anti-apoptotic properties. The aim of this study was to evaluate the effects of resveratrol on heart mitochondria. Resveratrol significantly decreased Fe(2+) + ascorbate oxidant system-induced lipid peroxide levels, preserved physiological levels of glutathione, and increased nitric oxide (NO) levels in mitochondria. Under calcium-mediated stress, there was a 2.7-fold increase in the NO levels, and a mild decoupling in the mitochondrial respiratory chain. These results provide a mechanism for and support the beneficial effects of resveratrol under pathological conditions induced by oxidative stress and calcium overload. In addition, these findings underscore the usefulness of resveratrol in the prevention of cardiovascular diseases.

  1. Depletion of intracellular calcium stores facilitates the influx of extracellular calcium in platelet derived growth factor stimulated A172 glioblastoma cells.

    PubMed

    Vereb, G; Szöllösi, J; Mátyus, L; Balázs, M; Hyun, W C; Feuerstein, B G

    1996-05-01

    Calcium signaling in non-excitable cells is the consequence of calcium release from intracellular stores, at times followed by entry of extracellular calcium through the plasma membrane. To study whether entry of calcium depends upon the level of saturation of intracellular stores, we measured calcium channel opening in the plasma membrane of single confluent A172 glioblastoma cells stimulated with platelet derived growth factor (PDGF) and/or bradykinin (BK). We monitored the entry of extracellular calcium by measuring manganese quenching of Indo-1 fluorescence. PDGF raised intracellular calcium concentration ([Ca2+]i) after a dose-dependent delay (tdel) and then opened calcium channels after a dose-independent delay (tch). At higher doses (> 3 nM), BK increased [Ca2+]i after a tdel approximately 0 s, and tch decreased inversely with both dose and peak [Ca2+]i. Experiments with thapsigargin (TG), BK, and PDGF indicated that BK and PDGF share intracellular Ca2+ pools that are sensitive to TG. When these stores were depleted by treatment with BK and intracellular BAPTA, tdel did not change, but tch fell to almost 0 s in PDGF stimulated cells, indicating that depletion of calcium stores affects calcium channel opening in the plasma membrane. Our data support the capacitative model for calcium channel opening and the steady-state model describing quantal Ca2+ release from intracellular stores.

  2. Intracellular sphingosine releases calcium from lysosomes

    PubMed Central

    Höglinger, Doris; Haberkant, Per; Aguilera-Romero, Auxiliadora; Riezman, Howard; Porter, Forbes D; Platt, Frances M; Galione, Antony; Schultz, Carsten

    2015-01-01

    To elucidate new functions of sphingosine (Sph), we demonstrate that the spontaneous elevation of intracellular Sph levels via caged Sph leads to a significant and transient calcium release from acidic stores that is independent of sphingosine 1-phosphate, extracellular and ER calcium levels. This photo-induced Sph-driven calcium release requires the two-pore channel 1 (TPC1) residing on endosomes and lysosomes. Further, uncaging of Sph leads to the translocation of the autophagy-relevant transcription factor EB (TFEB) to the nucleus specifically after lysosomal calcium release. We confirm that Sph accumulates in late endosomes and lysosomes of cells derived from Niemann-Pick disease type C (NPC) patients and demonstrate a greatly reduced calcium release upon Sph uncaging. We conclude that sphingosine is a positive regulator of calcium release from acidic stores and that understanding the interplay between Sph homeostasis, calcium signaling and autophagy will be crucial in developing new therapies for lipid storage disorders such as NPC. DOI: http://dx.doi.org/10.7554/eLife.10616.001 PMID:26613410

  3. Urine risk factors in children with calcium kidney stones and their siblings

    PubMed Central

    Bergsland, Kristin J.; Coe, Fredric L.; White, Mark D.; Erhard, Michael J.; DeFoor, William R.; Mahan, John D.; Schwaderer, Andrew L.; Asplin, John R.

    2012-01-01

    Calcium nephrolithiasis in children is increasing in prevalence and tends to be recurrent. Although children have a lower incidence of nephrolithiasis than adults, its etiology in children is less well understood; hence treatments targeted for adults may not be optimal in children. To better understand metabolic abnormalities in stone forming children, we compared chemical measurements and the crystallization properties of 24-hour urine collections from 129 stone formers matched to 105 non-stone forming siblings and 183 normal, healthy children with no family history of stones; all aged 6 to 17 years. The principal risk factor for calcium stone formation was hypercalciuria. Stone formers have strikingly higher calcium excretion along with high supersaturation for calcium oxalate and calcium phosphate, and a reduced distance between the upper limit of metastability and supersaturation for calcium phosphate, indicating increased risk of calcium phosphate crystallization. Other differences in urine chemistry that exist between adult stone formers and normal individuals such as hyperoxaluria, hypocitraturia, abnormal urine pH and low urine volume were not found in these children. Hence, hypercalciuria and a reduction in the gap between calcium phosphate upper limit of metastability and supersaturation are crucial determinants of stone risk. This highlights the importance of managing hypercalciuria in children with calcium stones. PMID:22358148

  4. Urine risk factors in children with calcium kidney stones and their siblings.

    PubMed

    Bergsland, Kristin J; Coe, Fredric L; White, Mark D; Erhard, Michael J; DeFoor, William R; Mahan, John D; Schwaderer, Andrew L; Asplin, John R

    2012-06-01

    Calcium nephrolithiasis in children is increasing in prevalence and tends to be recurrent. Although children have a lower incidence of nephrolithiasis than adults, its etiology in children is less well understood; hence, treatments targeted for adults may not be optimal in children. To better understand metabolic abnormalities in stone-forming children, we compared chemical measurements and the crystallization properties of 24-h urine collections from 129 stone formers matched to 105 non-stone-forming siblings and 183 normal, healthy children with no family history of stones, all aged 6 to 17 years. The principal risk factor for calcium stone formation was hypercalciuria. Stone formers have strikingly higher calcium excretion along with high supersaturation for calcium oxalate and calcium phosphate, and a reduced distance between the upper limit of metastability and supersaturation for calcium phosphate, indicating increased risk of calcium phosphate crystallization. Other differences in urine chemistry that exist between adult stone formers and normal individuals such as hyperoxaluria, hypocitraturia, abnormal urine pH, and low urine volume were not found in these children. Hence, hypercalciuria and a reduction in the gap between calcium phosphate upper limit of metastability and supersaturation are crucial determinants of stone risk. This highlights the importance of managing hypercalciuria in children with calcium stones.

  5. Blockade of store-operated calcium entry alleviates high glucose-induced neurotoxicity via inhibiting apoptosis in rat neurons.

    PubMed

    Xu, Zhenkuan; Xu, Wenzhe; Song, Yan; Zhang, Bin; Li, Feng; Liu, Yuguang

    2016-07-25

    Altered store-operated calcium entry (SOCE) has been suggested to be involved in many diabetic complications. However, the association of altered SOCE and diabetic neuronal damage remains unclear. This study aimed to investigate the effects of altered SOCE on primary cultured rat neuron injury induced by high glucose. Our data demonstrated that high glucose increased rat neuron injury and upregulated the expression of store-operated calcium channel (SOC). Inhibition of SOCE by a pharmacological inhibitor and siRNA knockdown of stromal interaction molecule 1 weakened the intracellular calcium overload, restored mitochondrial membrane potential, downregulated cytochrome C release and inhibited cell apoptosis. As well, treatment with the calcium chelator BAPTA-AM prevented cell apoptosis by ameliorating the high glucose-increased intracellular calcium level. These findings suggest that SOCE blockade may alleviate high glucose-induced neuronal damage by inhibiting apoptosis. SOCE might be a promising therapeutic target in diabetic neurotoxicity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. Octopamine and Dopamine differentially modulate the nicotine-induced calcium response in Drosophila Mushroom Body Kenyon Cells.

    PubMed

    Leyton, V; Goles, N I; Fuenzalida-Uribe, N; Campusano, J M

    2014-02-07

    In Drosophila associative olfactory learning, an odor, the conditioned stimulus (CS), is paired to an unconditioned stimulus (US). The CS and US information arrive at the Mushroom Bodies (MB), a Drosophila brain region that processes the information to generate new memories. It has been shown that olfactory information is conveyed through cholinergic inputs that activate nicotinic acetylcholine receptors (nAChRs) in the MB, while the US is coded by biogenic amine (BA) systems that innervate the MB. In this regard, the MB acts as a coincidence detector. A better understanding of the properties of the responses gated by nicotinic and BA receptors is required to get insights on the cellular and molecular mechanisms responsible for memory formation. In recent years, information has become available on the properties of the responses induced by nAChR activation in Kenyon Cells (KCs), the main neuronal MB population. However, very little information exists on the responses induced by aminergic systems in fly MB. Here we have evaluated some of the properties of the calcium responses gated by Dopamine (DA) and Octopamine (Oct) in identified KCs in culture. We report that exposure to BAs induces a fast but rather modest increase in intracellular calcium levels in cultured KCs. The responses to Oct and DA are fully blocked by a VGCC blocker, while they are differentially modulated by cAMP. Moreover, co-application of BAs and nicotine has different effects on intracellular calcium levels: while DA and nicotine effects are additive, Oct and nicotine induce a synergistic increase in calcium levels. These results suggest that a differential modulation of nicotine-induced calcium increase by DA and Oct could contribute to the events leading to learning and memory in flies. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  7. Nicotine-Induced Airway Smooth Muscle Cell Proliferation Involves TRPC6-Dependent Calcium Influx Via α7 nAChR.

    PubMed

    Hong, Wei; Peng, Gongyong; Hao, Binwei; Liao, Baoling; Zhao, Zhuxiang; Zhou, Yumin; Peng, Fang; Ye, Xiuqin; Huang, Lingmei; Zheng, Mengning; Pu, Jinding; Liang, Chunxiao; Yi, Erkang; Peng, Huanhuan; Li, Bing; Ran, Pixin

    2017-01-01

    The proliferation of human bronchial smooth muscle cells (HBSMCs) is a key pathophysiological component of airway remodeling in chronic obstructive pulmonary disease (COPD) for which pharmacotherapy is limited, and only slight improvements in survival have been achieved in recent decades. Cigarette smoke is a well-recognized risk factor for COPD; however, the pathogenesis of cigarette smoke-induced COPD remains incompletely understood. This study aimed to investigate the mechanisms by which nicotine affects HBSMC proliferation. Cell viability was assessed with a CCK-8 assay. Proliferation was measured by cell counting and EdU immunostaining. Fluorescence calcium imaging was performed to measure intracellular Ca2+ concentration ([Ca2+]i). The results showed that nicotine promotes HBSMC proliferation, which is accompanied by elevated store-operated calcium entry (SOCE), receptor-operated calcium entry (ROCE) and basal [Ca2+]i in HBSMCs. Moreover, we also confirmed that canonical transient receptor potential protein 6 (TRPC6) and α7 nicotinic acetylcholine receptor (α7 nAChR) are involved in nicotine-induced upregulation of cell proliferation. Furthermore, we verified that activation of the PI3K/Akt signaling pathway plays a pivotal role in nicotine-enhanced proliferation and calcium influx in HBSMCs. Inhibition of α7 nAChR significantly decreased Akt phosphorylation levels, and LY294002 inhibited the protein expression levels of TRPC6. Herein, these data provide compelling evidence that calcium entry via the α7 nAChR-PI3K/Akt-TRPC6 signaling pathway plays an important role in the physiological regulation of airway smooth muscle cell proliferation, representing an important target for augmenting airway remodeling. © 2017 The Author(s). Published by S. Karger AG, Basel.

  8. Genetically Encoded Calcium Indicators For Studying Long-Term Calcium Dynamics During Apoptosis

    PubMed Central

    Garcia, M. Iveth; Chen, Jessica J.; Boehning, Darren

    2017-01-01

    Intracellular calcium release is essential for regulating almost all cellular functions. Specific spatio-temporal patterns of cytosolic calcium elevations are critical determinants of cell fate in response to pro-apoptotic cellular stressors. As the apoptotic program can take hours or days, measurement of long-term calcium dynamics are essential for understanding the mechanistic role of calcium in apoptotic cell death. Due to the technical limitations of using calcium-sensitive dyes to measure cytosolic calcium little is known about long-term calcium dynamics in living cells after treatment with apoptosis-inducing drugs. Genetically encoded calcium indicators could potentially overcome some of the limitations of calcium-sensitive dyes. Here, we compared the performance of the genetically encoded calcium indicators GCaMP6s and GCaMP6f with the ratiometric dye Fura-2. GCaMP6s performed as well or better than Fura-2 in detecting agonist-induced calcium transients. We then examined the utility of GCaMP6s for continuously measuring apoptotic calcium release over the course of ten hours after treatment with staurosporine. We found that GCaMP6s was suitable for measuring apoptotic calcium release over long time courses and revealed significant heterogeneity in calcium release dynamics in individual cells challenged with staurosporine. Our results suggest GCaMP6s is an excellent indicator for monitoring long-term changes cytosolic calcium during apoptosis. PMID:28073595

  9. Effect of neurotrophin-3 precursor on glutamate-induced calcium homeostasis deregulation in rat cerebellum granule cells.

    PubMed

    Safina, Dina R; Surin, Alexander M; Pinelis, Vsevolod G; Kostrov, Sergey V

    2015-12-01

    Neurotrophin-3 (NT-3) belongs to the family of highly conserved dimeric growth factors that controls the differentiation and activity of various neuronal populations. Mammals contain both the mature (NT-3) and the precursor (pro-NT-3) forms of neurotrophin. Members of the neurotrophin family are involved in the regulation of calcium homeostasis in neurons; however, the role of NT-3 and pro-NT-3 in this process remains unclear. The current study explores the effects of NT-3 and pro-NT-3 on disturbed calcium homeostasis and decline of mitochondrial potential induced by a neurotoxic concentration of glutamate (Glu; 100 µM) in the primary culture of rat cerebellar granule cells. In this Glu excitotoxicity model, mature NT-3 had no effect on the induced changes in Ca²⁺ homeostasis. In contrast, pro-NT-3 decreased the period of delayed calcium deregulation (DCD) and concurrent strong mitochondrial depolarization. According to the amplitude of the increase in the intracellular free Ca²⁺ concentration ([Ca²⁺]i ) and Fura-2 fluorescence quenching by Mn²⁺ within the first 20 sec of exposure to Glu, pro-NT-3 had no effect on the initial rate of Ca²⁺ entry into neurons. During the lag period preceding DCD, the mean amplitude of [Ca²⁺]i rise was 1.2-fold greater in the presence of pro-NT-3 than in the presence of Glu alone (1.67 ±  0.07 and 1.39 ± 0.04, respectively, P < 0.05). The Glu-induced changes in Са²⁺ homeostasis in the presence of pro-NT-3 likely are due to the decreased rate of Са²⁺ removal from the cytosol during the DCD latency period. © 2015 Wiley Periodicals, Inc.

  10. Calcium as a cardiovascular toxin in CKD-MBD.

    PubMed

    Moe, Sharon M

    2017-07-01

    Disordered calcium balance and homeostasis are common in patients with chronic kidney disease. Such alterations are commonly associated with abnormal bone remodeling, directly and indirectly. Similarly, positive calcium balance may also be a factor in the pathogenesis of extra skeletal soft tissue and arterial calcification. Calcium may directly affect cardiac structure and function through direct effects to alter cell signaling due to abnormal intracellular calcium homeostasis 2) extra-skeletal deposition of calcium and phosphate in the myocardium and small cardiac arterioles, 3) inducing cardiomyocyte hypertrophy through calcium and hormone activation of NFAT signaling mechanisms, and 4) increased aorta calcification resulting in chronic increased afterload leading to hypertrophy. Similarly, calcium may alter vascular smooth muscle cell function and affect cell signaling which may predispose to a proliferative phenotype important in arteriosclerosis and arterial calcification. Thus, disorders of calcium balance and homeostasis due to CKD-MBD may play a role in the high cardiovascular burden observed in patients with CKD. Published by Elsevier Inc.

  11. Atorvastatin calcium inhibits phenotypic modulation of PDGF-BB-induced VSMCs via down-regulation the Akt signaling pathway.

    PubMed

    Chen, Shuang; Liu, Baoqin; Kong, Dehui; Li, Si; Li, Chao; Wang, Huaqin; Sun, Yingxian

    2015-01-01

    Plasticity of vascular smooth muscle cells (VSMCs) plays a central role in the onset and progression of proliferative vascular diseases. In adult tissue, VSMCs exist in a physiological contractile-quiescent phenotype, which is defined by lack of the ability of proliferation and migration, while high expression of contractile marker proteins. After injury to the vessel, VSMC shifts from a contractile phenotype to a pathological synthetic phenotype, associated with increased proliferation, migration and matrix secretion. It has been demonstrated that PDGF-BB is a critical mediator of VSMCs phenotypic switch. Atorvastatin calcium, a selective inhibitor of 3-hydroxy-3-methyl-glutaryl l coenzyme A (HMG-CoA) reductase, exhibits various protective effects against VSMCs. In this study, we investigated the effects of atorvastatin calcium on phenotype modulation of PDGF-BB-induced VSMCs and the related intracellular signal transduction pathways. Treatment of VSMCs with atorvastatin calcium showed dose-dependent inhibition of PDGF-BB-induced proliferation. Atorvastatin calcium co-treatment inhibited the phenotype modulation and cytoskeleton rearrangements and improved the expression of contractile phenotype marker proteins such as α-SM actin, SM22α and calponin in comparison with PDGF-BB alone stimulated VSMCs. Although Akt phosphorylation was strongly elicited by PDGF-BB, Akt activation was attenuated when PDGF-BB was co-administrated with atorvastatin calcium. In conclusion, atorvastatin calcium inhibits phenotype modulation of PDGF-BB-induced VSMCs and activation of the Akt signaling pathway, indicating that Akt might play a vital role in the modulation of phenotype.

  12. Atorvastatin Calcium Inhibits Phenotypic Modulation of PDGF-BB-Induced VSMCs via Down-Regulation the Akt Signaling Pathway

    PubMed Central

    Chen, Shuang; Liu, Baoqin; Kong, Dehui; Li, Si; Li, Chao; Wang, Huaqin; Sun, Yingxian

    2015-01-01

    Plasticity of vascular smooth muscle cells (VSMCs) plays a central role in the onset and progression of proliferative vascular diseases. In adult tissue, VSMCs exist in a physiological contractile-quiescent phenotype, which is defined by lack of the ability of proliferation and migration, while high expression of contractile marker proteins. After injury to the vessel, VSMC shifts from a contractile phenotype to a pathological synthetic phenotype, associated with increased proliferation, migration and matrix secretion. It has been demonstrated that PDGF-BB is a critical mediator of VSMCs phenotypic switch. Atorvastatin calcium, a selective inhibitor of 3-hydroxy-3-methyl-glutaryl l coenzyme A (HMG-CoA) reductase, exhibits various protective effects against VSMCs. In this study, we investigated the effects of atorvastatin calcium on phenotype modulation of PDGF-BB-induced VSMCs and the related intracellular signal transduction pathways. Treatment of VSMCs with atorvastatin calcium showed dose-dependent inhibition of PDGF-BB-induced proliferation. Atorvastatin calcium co-treatment inhibited the phenotype modulation and cytoskeleton rearrangements and improved the expression of contractile phenotype marker proteins such as α-SM actin, SM22α and calponin in comparison with PDGF-BB alone stimulated VSMCs. Although Akt phosphorylation was strongly elicited by PDGF-BB, Akt activation was attenuated when PDGF-BB was co-administrated with atorvastatin calcium. In conclusion, atorvastatin calcium inhibits phenotype modulation of PDGF-BB-induced VSMCs and activation of the Akt signaling pathway, indicating that Akt might play a vital role in the modulation of phenotype. PMID:25874930

  13. [Effect of 2,3-butanedione monoxime on calcium paradox-induced heart injury in rats].

    PubMed

    Kong, Ling-Heng; Gu, Xiao-Ming; Su, Xing-Li; Sun, Na; Wei, Ming; Zhu, Juan-Xia; Chang, Pan; Zhou, Jing-Jun

    2016-05-01

    To investigate the Effect of 2,3-butanedione monoxime (BDM) on calcium paradox-induced heart injury and its underlying mechanisms. Thirty-two adult male SD rats were randomized into 4 groups, namely the control group, BDM treatment control group, calcium paradox group, and BDM treatment group. Isolated Sprague Dawley male rat hearts underwent Langendorff perfusion and the left ventricular pressure (LVP) and left ventricular end-diastolic pressure (LVEDP) were monitored. Left ventricular developed pressure (LVDP) was calculated to evaluate the myocardial performance. Lactate dehydrogenase (LDH) content in the coronary flow was determined. Triphenyltetrazolium chloride staining was used to measure the infarct size, and myocardial cell apoptosis was tested with TUNEL method. Western blotting was used to determine the expression of cleaved caspase-3 and cytochrome c. Compared with the control group, BDM at 20 mmol/L had no effect on cardiac performance, cell death, apoptotic index or the content of LDH, cleaved caspase-3 and cytochrome c at the end of perfusion under control conditions (P>0.05). Calcium paradox treatment significantly decreased the cardiac function and the level of LVDP and induced a larger infarct size (P<0.01), an increased myocardial apoptosis index (P<0.01), and up-regulated expressions of cleaved caspase-3 and cytochrome c (P<0.01). BDM (20 mmol/L) significantly attenuated these effects induced by calcium paradox, and markedly down-regulated the levels of LVEDP and LDH (P<0.01), lowered myocardial apoptosis index, decreased the content of cleaved caspase-3 and cytochrome c (P<0.01), increased LVDP, and reduced the infarct size (P<0.01). BDM suppresses cell apoptosis and contracture and improves heart function and cell survival in rat hearts exposed to calcium paradox, suggesting the value of BDM as an potential drug for myocardial ischemia reperfusion injur.

  14. Activation of the edema factor of Bacillus anthracis by calmodulin: evidence of an interplay between the EF-calmodulin interaction and calcium binding.

    PubMed

    Laine, Elodie; Martínez, Leandro; Blondel, Arnaud; Malliavin, Thérèse E

    2010-10-06

    Calmodulin (CaM) is a remarkably flexible protein which can bind multiple targets in response to changes in intracellular calcium concentration. It contains four calcium-binding sites, arranged in two globular domains. The calcium affinity of CaM N-terminal domain (N-CaM) is dramatically reduced when the complex with the edema factor (EF) of Bacillus anthracis is formed. Here, an atomic explanation for this reduced affinity is proposed through molecular dynamics simulations and free energy perturbation calculations of the EF-CaM complex starting from different crystallographic models. The simulations show that electrostatic interactions between CaM and EF disfavor the opening of N-CaM domains usually induced by calcium binding. Relative calcium affinities of the N-CaM binding sites are probed by free energy perturbation, and dissociation probabilities are evaluated with locally enhanced sampling simulations. We show that EF impairs calcium binding on N-CaM through a direct conformational restraint on Site 1, by an indirect destabilization of Site 2, and by reducing the cooperativity between the two sites. Copyright © 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  15. Acute administration of tumour necrosis factorinduces spontaneous calcium release via the reactive oxygen species pathway in atrial myocytes.

    PubMed

    Zuo, Song; Li, Lin-Ling; Ruan, Yan-Fei; Jiang, Le; Li, Xin; Li, Song-Nan; Wen, Song-Nan; Bai, Rong; Liu, Nian; Du, Xin; Dong, Jian-Zeng; Ma, Chang-Sheng

    2017-10-17

    The arrhythmogenic mechanisms of atrial fibrillation (AF) that are induced by acute inflammation, such as postoperative AF, are not well understood. We investigated the acute effects of tumour necrosis factor-α (TNF-α) that mimic acute inflammation on Ca2+ handling in isolated atrial myocytes and its underlying mechanisms. Cytosol Ca2+ handling and mitochondrial reactive oxygen species (ROS) production were studied in freshly isolated atrial myocytes of wild-type mice that were exposed to TNF-α (0.05 ng/mL) for 2 h by Ionoptix and confocal microscopy. The acute effects of TNF-α on Ca2+ handling were decreased amplitudes and prolonged decay times of Ca2+ transients in isolated atrial myocytes. A significant reduction in the sarcoplasmic reticulum (SR) Ca2+ content was detected in TNF-α treated cells, which was associated with increased spontaneous Ca2+ release events. In particular, physiological concentrations of TNF-α dramatically promoted the frequency of spontaneous Ca2+ waves and Ca2+ sparks, while the spark mass presented with reduced amplitudes and prolonged durations. The underlying mechanisms of pro-arrhythmic effects of TNF-α were further investigated. Acute exposure to TNF-α rapidly promoted mitochondrial ROS production that was correlated with the acute effect of TNF-α on Ca2+ handling, and enhanced the oxidation of calcium/calmodulin-dependent protein kinase II (CaMKII) and the phosphorylation of RyR2. However, the performance of ROS inhibitor, DL-Dithiothreitol (DTT), reversed Ca2+ handling disorders induced by TNF-α. Tumour necrosis factor-α rapidly increases spontaneous Ca2+ release and promotes atrial arrhythmogenesis via the ROS pathway, which suggests that antioxidant therapy is a promising strategy for acute inflammation related AF. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions, please email: journals.permissions@oup.com.

  16. Genetically encoded calcium indicators for studying long-term calcium dynamics during apoptosis.

    PubMed

    Garcia, M Iveth; Chen, Jessica J; Boehning, Darren

    2017-01-01

    Intracellular calcium release is essential for regulating almost all cellular functions. Specific spatio-temporal patterns of cytosolic calcium elevations are critical determinants of cell fate in response to pro-apoptotic cellular stressors. As the apoptotic program can take hours or days, measurement of long-term calcium dynamics are essential for understanding the mechanistic role of calcium in apoptotic cell death. Due to the technical limitations of using calcium-sensitive dyes to measure cytosolic calcium little is known about long-term calcium dynamics in living cells after treatment with apoptosis-inducing drugs. Genetically encoded calcium indicators could potentially overcome some of the limitations of calcium-sensitive dyes. Here, we compared the performance of the genetically encoded calcium indicators GCaMP6s and GCaMP6f with the ratiometric dye Fura-2. GCaMP6s performed as well or better than Fura-2 in detecting agonist-induced calcium transients. We then examined the utility of GCaMP6s for continuously measuring apoptotic calcium release over the course of ten hours after treatment with staurosporine. We found that GCaMP6s was suitable for measuring apoptotic calcium release over long time courses and revealed significant heterogeneity in calcium release dynamics in individual cells challenged with staurosporine. Our results suggest GCaMP6s is an excellent indicator for monitoring long-term changes cytosolic calcium during apoptosis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Assessment of fluoride-induced changes on physicochemical and structural properties of bone and the impact of calcium on its control in rabbits.

    PubMed

    Gopalakrishnan, Subarayan Bothi; Viswanathan, Gopalan

    2012-03-01

    Bone deformities caused by the chronic intake of large quantities of fluoride and the beneficial effect of calcium on its control have been studied for many years, but only limited data are available on the quantitative effect of fluoride intake and the beneficial impact of calcium on fluoride-induced changes in bone at the molecular level. It is necessary to determine the degree of fluoride-induced changes in bone at different levels of fluoride intake to evaluate the optimum safe intake level of fluoride for maintaining bone health and quality. The ameliorative effect of calcium at different dose levels on minimizing fluoride-induced changes in bone is important to quantify the amount of calcium intake necessary for reducing fluoride toxicity. Thirty rabbits, 2 months old, were divided into five groups. Group I animals received 1 mg/l fluoride and 0.11% calcium diet; groups II and III received 10 mg/l fluoride and diet with 0.11% or 2.11% calcium, respectively; and groups IV and V received 150 mg/l fluoride and diet with 2.11% or 0.11% calcium, respectively. Analysis of bone density, ash content, fluoride, calcium, phosphorus, and Ca:P molar ratio levels after 6 months of treatment indicated that animals that received high fluoride with low-calcium diet showed significant detrimental changes in physicochemical properties of bone. Animals that received fluoride with high calcium intake showed notable amelioration of the impact of calcium on fluoride-induced changes in bone. The degree of fluoride-induced characteristic changes in structural properties such as crystalline size, crystallinity, and crystallographic "c"-axis length of bone apatite cells was also assessed by X-ray diffraction and Fourier transform infrared studies. X-ray images showed bone deformity changes such as transverse stress growth lines, soft tissue ossification, and calcification in different parts of bones as a result of high fluoride accumulation and the beneficial role of calcium

  18. Growth hormone secretagogues prevent dysregulation of skeletal muscle calcium homeostasis in a rat model of cisplatin‐induced cachexia

    PubMed Central

    Conte, Elena; Camerino, Giulia Maria; Mele, Antonietta; De Bellis, Michela; Pierno, Sabata; Rana, Francesco; Fonzino, Adriano; Caloiero, Roberta; Rizzi, Laura; Bresciani, Elena; Ben Haj Salah, Khoubaib; Fehrentz, Jean‐Alain; Martinez, Jean; Giustino, Arcangela; Mariggiò, Maria Addolorata; Coluccia, Mauro; Tricarico, Domenico; Lograno, Marcello Diego; De Luca, Annamaria; Torsello, Antonio; Conte, Diana

    2017-01-01

    Abstract Background Cachexia is a wasting condition associated with cancer types and, at the same time, is a serious and dose‐limiting side effect of cancer chemotherapy. Skeletal muscle loss is one of the main characteristics of cachexia that significantly contributes to the functional muscle impairment. Calcium‐dependent signaling pathways are believed to play an important role in skeletal muscle decline observed in cachexia, but whether intracellular calcium homeostasis is affected in this situation remains uncertain. Growth hormone secretagogues (GHS), a family of synthetic agonists of ghrelin receptor (GHS‐R1a), are being developed as a therapeutic option for cancer cachexia syndrome; however, the exact mechanism by which GHS interfere with skeletal muscle is not fully understood. Methods By a multidisciplinary approach ranging from cytofluorometry and electrophysiology to gene expression and histology, we characterized the calcium homeostasis in fast‐twitch extensor digitorum longus (EDL) muscle of adult rats with cisplatin‐induced cachexia and established the potential beneficial effects of two GHS (hexarelin and JMV2894) at this level. Additionally, in vivo measures of grip strength and of ultrasonography recordings allowed us to evaluate the functional impact of GHS therapeutic intervention. Results Cisplatin‐treated EDL muscle fibres were characterized by a ~18% significant reduction of the muscle weight and fibre diameter together with an up‐regulation of atrogin1/Murf‐1 genes and a down‐regulation of Pgc1‐a gene, all indexes of muscle atrophy, and by a two‐fold increase in resting intracellular calcium, [Ca2+]i, compared with control rats. Moreover, the amplitude of the calcium transient induced by caffeine or depolarizing high potassium solution as well as the store‐operated calcium entry were ~50% significantly reduced in cisplatin‐treated rats. Calcium homeostasis dysregulation parallels with changes of functional ex vivo

  19. Curcumin induces endoplasmic reticulum stress-associated apoptosis in human papillary thyroid carcinoma BCPAP cells via disruption of intracellular calcium homeostasis.

    PubMed

    Zhang, Li; Cheng, Xian; Xu, Shichen; Bao, Jiandong; Yu, Huixin

    2018-06-01

    Thyroid cancer is the most common endocrine tumor. Our previous studies have demonstrated that curcumin can induce apoptosis in human papillary thyroid carcinoma BCPAP cells. However, the underlined mechanism has not been clearly elucidated. Endoplasmic reticulum (ER) is a major organelle for synthesis, maturation, and folding proteins as well as a large store for Ca. Overcoming chronically activated ER stress by triggering pro-apoptotic pathways of the unfolded protein response (UPR) is a novel strategy for cancer therapeutics. Our study aimed to uncover the ER stress pathway involved in the apoptosis caused by curcumin. BCPAP cells were treated with different doses of curcumin (12.5-50 μM). Annexin V/PI double staining was used to determine cell apoptosis. Rhod-2/AM calcium fluorescence probe assay was performed to measure the calcium level of endoplasmic reticulum. Western blot was used to examine the expression of ER stress marker C/EBP homologous protein 10 (CHOP) and glucose-regulated protein 78 (GRP78). X-box binding protein1 (XBP-1) spliced form was examined by reverse transcriptase-polymerase chain reaction (RT-PCR). Curcumin significantly inhibited anchorage-independent cell growth and induced apoptosis in BCPAP cells. Curcumin induced ER stress and UPR responses in a dose- and time-dependent manner, and the chemical chaperone 4-phenylbutyrate (4-PBA) partially reversed the antigrowth activity of curcumin. Moreover, curcumin significantly increased inositol-requiring enzyme 1α (IRE1α) phosphorylation and XBP-1 mRNA splicing to induce a subsets of ER chaperones. Increased cleavage of activating transcription factor 6 (ATF6), which enhances expression of its downstream target CHOP was also observed. Furthermore, curcumin induced intracellular Ca influx through inhibition of the sarco-endoplasmic reticulum ATPase 2A (SERCA2) pump. The increased cytosolic Ca then bound to calmodulin to activate calcium/calmodulin-dependent protein kinase II (Ca

  20. Biofilm-induced calcium carbonate precipitation: application in the subsurface

    NASA Astrophysics Data System (ADS)

    Phillips, A. J.; Eldring, J.; Lauchnor, E.; Hiebert, R.; Gerlach, R.; Mitchell, A. C.; Esposito, R.; Cunningham, A. B.; Spangler, L.

    2012-12-01

    We have investigated mitigation strategies for sealing high permeability regions, like fractures, in the subsurface. This technology has the potential to, for example, improve the long-term security of geologically-stored carbon dioxide (CO2) by sealing fractures in cap rocks or to mitigate leakage pathways to prevent contamination of overlying aquifers from hydraulic fracturing fluids. Sealing technologies using low-viscosity fluids are advantageous since they potentially reduce the necessary injection pressures and increase the radius of influence around injection wells. In this technology, aqueous solutions and suspensions are used to promote microbially-induced mineral precipitation which can be applied in subsurface environments. To this end, a strategy was developed to twice seal a hydraulically fractured, 74 cm (2.4') diameter Boyles Sandstone core, collected in North-Central Alabama, with biofilm-induced calcium carbonate (CaCO3) precipitates under ambient pressures. Sporosarcina pasteurii biofilms were established and calcium and urea containing reagents were injected to promote saturation conditions favorable for CaCO3 precipitation followed by growth reagents to resuscitate the biofilm's ureolytic activity. Then, in order to evaluate this process at relevant deep subsurface pressures, a novel high pressure test vessel was developed to house the 74 cm diameter core under pressures as high as 96 bar (1,400 psi). After determining that no impact to the fracture permeability occurred due to increasing overburden pressure, the fractured core was sealed under subsurface relevant pressures relating to 457 meters (1,500 feet) below ground surface (44 bar (650 psi) overburden pressure). After fracture sealing under both ambient and subsurface relevant pressure conditions, the sandstone core withstood three times higher well bore pressure than during the initial fracturing event, which occurred prior to biofilm-induced CaCO3 mineralization. These studies suggest

  1. Growth hormone secretagogues prevent dysregulation of skeletal muscle calcium homeostasis in a rat model of cisplatin-induced cachexia.

    PubMed

    Conte, Elena; Camerino, Giulia Maria; Mele, Antonietta; De Bellis, Michela; Pierno, Sabata; Rana, Francesco; Fonzino, Adriano; Caloiero, Roberta; Rizzi, Laura; Bresciani, Elena; Ben Haj Salah, Khoubaib; Fehrentz, Jean-Alain; Martinez, Jean; Giustino, Arcangela; Mariggiò, Maria Addolorata; Coluccia, Mauro; Tricarico, Domenico; Lograno, Marcello Diego; De Luca, Annamaria; Torsello, Antonio; Conte, Diana; Liantonio, Antonella

    2017-06-01

    Cachexia is a wasting condition associated with cancer types and, at the same time, is a serious and dose-limiting side effect of cancer chemotherapy. Skeletal muscle loss is one of the main characteristics of cachexia that significantly contributes to the functional muscle impairment. Calcium-dependent signaling pathways are believed to play an important role in skeletal muscle decline observed in cachexia, but whether intracellular calcium homeostasis is affected in this situation remains uncertain. Growth hormone secretagogues (GHS), a family of synthetic agonists of ghrelin receptor (GHS-R1a), are being developed as a therapeutic option for cancer cachexia syndrome; however, the exact mechanism by which GHS interfere with skeletal muscle is not fully understood. By a multidisciplinary approach ranging from cytofluorometry and electrophysiology to gene expression and histology, we characterized the calcium homeostasis in fast-twitch extensor digitorum longus (EDL) muscle of adult rats with cisplatin-induced cachexia and established the potential beneficial effects of two GHS (hexarelin and JMV2894) at this level. Additionally, in vivo measures of grip strength and of ultrasonography recordings allowed us to evaluate the functional impact of GHS therapeutic intervention. Cisplatin-treated EDL muscle fibres were characterized by a ~18% significant reduction of the muscle weight and fibre diameter together with an up-regulation of atrogin1/Murf-1 genes and a down-regulation of Pgc1-a gene, all indexes of muscle atrophy, and by a two-fold increase in resting intracellular calcium, [Ca 2+ ] i , compared with control rats. Moreover, the amplitude of the calcium transient induced by caffeine or depolarizing high potassium solution as well as the store-operated calcium entry were ~50% significantly reduced in cisplatin-treated rats. Calcium homeostasis dysregulation parallels with changes of functional ex vivo (excitability and resting macroscopic conductance) and in

  2. Selective dopamine receptor 4 activation mediates the hippocampal neuronal calcium response via IP3 and ryanodine receptors.

    PubMed

    Wang, Ya-Li; Wang, Jian-Gang; Guo, Fang-Li; Gao, Xia-Huan; Zhao, Dan-Dan; Zhang, Lin; Wang, Jian-Zhi; Lu, Cheng-Biao

    2017-09-01

    Intracellular calcium is a key factor in most cellular processes, including cell growth, differentiation, proliferation and neurotransmitter release. Dopamine (DA) mediates synaptic transmission by regulating the intracellular calcium content. It is not clear, however, which specific subunit of the DA receptor contributes to DA modulation of intracellular calcium content changes. Through the traditional technique of Fura-2 calcium imaging, this study demonstrated that the DA can induce transient calcium in cultured hippocampal neurons and that this response can be mimicked by a selective dopamine receptor 4 (DR4) agonist PD168077 (PD). PD-induced calcium transience can be blocked by a calcium chelator, such as BAPTA-AM, or by pre-treatment of neurons with thapsigargin, a IP 3 receptor antagonist, or a micromolar concentration of ryanodine, a ryanodine receptor (RyR) antagonist. However PD-induced calcium transience cannot be blocked by pre-treatment of neurons with a free-calcium medium or a cocktail of NMDA receptor, L-type calcium channel and alpha7 nicotinic acetylcholine receptor blockers. These results indicate that the calcium response induced by DR4 activation is mainly through activation of IP 3 receptor in internal stores, which is likely to contribute to the DA modulation of synaptic transmission and cognitive function. Copyright © 2017. Published by Elsevier B.V.

  3. Mutant SOD1-expressing astrocytes release toxic factors that trigger motoneuron death by inducing hyperexcitability

    PubMed Central

    Fritz, Elsa; Izaurieta, Pamela; Weiss, Alexandra; Mir, Franco R.; Rojas, Patricio; Gonzalez, David; Rojas, Fabiola; Brown, Robert H.; Madrid, Rodolfo

    2013-01-01

    Amyotrophic lateral sclerosis (ALS) is a devastating paralytic disorder caused by dysfunction and degeneration of motoneurons starting in adulthood. Recent studies using cell or animal models document that astrocytes expressing disease-causing mutations of human superoxide dismutase 1 (hSOD1) contribute to the pathogenesis of ALS by releasing a neurotoxic factor(s). Neither the mechanism by which this neurotoxic factor induces motoneuron death nor its cellular site of action has been elucidated. Here we show that acute exposure of primary wild-type spinal cord cultures to conditioned medium derived from astrocytes expressing mutant SOD1 (ACM-hSOD1G93A) increases persistent sodium inward currents (PCNa), repetitive firing, and intracellular calcium transients, leading to specific motoneuron death days later. In contrast to TTX, which paradoxically increased twofold the amplitude of calcium transients and killed motoneurons, reduction of hyperexcitability by other specific (mexiletine) and nonspecific (spermidine and riluzole) blockers of voltage-sensitive sodium (Nav) channels restored basal calcium transients and prevented motoneuron death induced by ACM-hSOD1G93A. These findings suggest that riluzole, the only FDA-approved drug with known benefits for ALS patients, acts by inhibiting hyperexcitability. Together, our data document that a critical element mediating the non-cell-autonomous toxicity of ACM-hSOD1G93A on motoneurons is increased excitability, an observation with direct implications for therapy of ALS. PMID:23486205

  4. Pulsed electromagnetic fields promote the proliferation and differentiation of osteoblasts by reinforcing intracellular calcium transients.

    PubMed

    Tong, Jie; Sun, Lijun; Zhu, Bin; Fan, Yun; Ma, Xingfeng; Yu, Liyin; Zhang, Jianbao

    2017-10-01

    Pulsed electromagnetic fields (PEMF) can be used to treat bone-related diseases, but the underlying mechanism remains unclear, especially the process by which PEMFs initiate biological effects. In this study, we demonstrated the effects of PEMF on proliferation and differentiation of osteoblasts using the model of calcium transients induced by high extracellular calcium. Our results showed that PEMF can increase both the percentage of responding cells and amplitude of intracellular calcium transients induced by high extracellular calcium stimulation. Compared with corresponding extracellular calcium levels, PEMF stimulation increased proliferation and differentiation of osteoblasts and related gene expressions, such as insulin-like growth factor 1 (IGF-1), alkaline phosphatase (ALP), runt-related transcription factor 2 (Runx2), and osteocalcin (OCN), which can be completely abolished by BAPTA-AM. Moreover, PEMF did not affect proliferation and differentiation of osteoblasts if no intracellular calcium transient was present in osteoblasts during PEMF exposure. Our results revealed that PEMF affects osteoblast proliferation and differentiation through enhanced intracellular calcium transients, which provided a cue to treat bone-related diseases with PEMF. Bioelectromagnetics. 38:541-549, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  5. Heteromerization of G2A and OGR1 enhances proton sensitivity and proton-induced calcium signals.

    PubMed

    Huang, Ya-Han; Su, Yeu-Shiuan; Chang, Chung-Jen; Sun, Wei-Hsin

    2016-12-01

    Proton-sensing G-protein-coupled receptors (GPCRs; OGR1, GPR4, G2A, TDAG8), with full activation at pH 6.4 ∼ 6.8, are important to pH homeostasis, immune responses and acid-induced pain. Although G2A mediates the G13-Rho pathway in response to acid, whether G2A activates Gs, Gi or Gq proteins remains debated. In this study, we examined the response of this fluorescence protein-tagged OGR1 family to acid stimulation in HEK293T cells. G2A did not generate detectable intracellular calcium or cAMP signals or show apparent receptor redistribution with moderate acid (pH ≥ 6.0) stimulation but reduced cAMP accumulation under strong acid stimulation (pH ≤ 5.5). Surprisingly, coexpression of OGR1- and G2A-enhanced proton sensitivity and proton-induced calcium signals. This alteration is attributed to oligomerization of OGR1 and G2A. The oligomeric potential locates receptors at a specific site, which leads to enhanced proton-induced calcium signals through channels.

  6. Glycine Receptor Activation Impairs ATP-Induced Calcium Transients in Cultured Cortical Astrocytes

    PubMed Central

    Morais, Tatiana P.; Coelho, David; Vaz, Sandra H.; Sebastião, Ana M.; Valente, Cláudia A.

    2018-01-01

    In central nervous system, glycine receptor (GlyR) is mostly expressed in the spinal cord and brainstem, but glycinergic transmission related elements have also been identified in the brain. Astrocytes are active elements at the tripartite synapse, being responsible for the maintenance of brain homeostasis and for the fine-tuning of synaptic activity. These cells communicate, spontaneously or in response to a stimulus, by elevations in their cytosolic calcium (calcium transients, Ca2+T) that can be propagated to other cells. How these Ca2+T are negatively modulated is yet poorly understood. In this work, we evaluated GlyR expression and its role on calcium signaling modulation in rat brain astrocytes. We first proved that GlyR, predominantly subunits α2 and β, was expressed in brain astrocytes and its localization was confirmed in the cytoplasm and astrocytic processes by immunohistochemistry assays. Calcium imaging experiments in cultured astrocytes showed that glycine (500 μM), a GlyR agonist, caused a concentration-dependent reduction in ATP-induced Ca2+T, an effect abolished by the GlyR antagonist, strychnine (0.8 μM), as well as by nocodazole (1 μM), known to impair GlyR anchorage to the plasma membrane. This effect was mimicked by activation of GABAAR, another Cl--permeable channel. In summary, we demonstrated that GlyR activation in astrocytes mediates an inhibitory effect upon ATP induced Ca2+T, which most probably involves changes in membrane permeability to Cl- and requires GlyR anchorage at the plasma membrane. GlyR in astrocytes may thus be part of a mechanism to modulate astrocyte-to-neuron communication. PMID:29386993

  7. Hyperkalemia induced by the calcium channel blocker, benidipine.

    PubMed

    Imamura, Takuroh; Matsuura, Yunosuke; Nagoshi, Toshiro; Ishikawa, Tetsunori; Date, Haruhiko; Kita, Toshihiro; Matsuyama, Akihiko; Matsuo, Takeshi; Eto, Tanenao

    2003-06-01

    A 73-year-old hypertensive, non-diabetic woman without obvious renal dysfunction had frequently been hyperkalemic over four years after receiving antihypertensive drugs including the calcium channel blocker (CCB) benidipine. One week after all medications were accidentally discontinued, the serum potassium level returned to normal. After we obtained the informed consent of the patient, benidipine alone was administered again for over two weeks and hyperkalemia developed once more. This previously uncommon side effect of hyperkalemia induced by benidipine is not very serious but it is apt to be overlooked. Since CCBs are now widely prescribed, the development of hyperkalemia should be considered.

  8. Zinc oxide nanoparticles decrease the expression and activity of plasma membrane calcium ATPase, disrupt the intracellular calcium homeostasis in rat retinal ganglion cells.

    PubMed

    Guo, Dadong; Bi, Hongsheng; Wang, Daoguang; Wu, Qiuxin

    2013-08-01

    Zinc oxide nanoparticle is one of the most important materials with diverse applications. However, it has been reported that zinc oxide nanoparticles are toxic to organisms, and that oxidative stress is often hypothesized to be an important factor in cytotoxicity mediated by zinc oxide nanoparticles. Nevertheless, the mechanism of toxicity of zinc oxide nanoparticles has not been completely understood. In this study, we investigated the cytotoxic effect of zinc oxide nanoparticles and the possible molecular mechanism involved in calcium homeostasis mediated by plasma membrane calcium ATPase in rat retinal ganglion cells. Real-time cell electronic sensing assay showed that zinc oxide nanoparticles could exert cytotoxic effect on rat retinal ganglion cells in a concentration-dependent manner; flow cytometric analysis indicated that zinc oxide nanoparticles could lead to cell damage by inducing the overproduction of reactive oxygen species. Furthermore, zinc oxide nanoparticles could also apparently decrease the expression level and their activity of plasma membrane calcium ATPase, which finally disrupt the intracellular calcium homeostasis and result in cell death. Taken together, zinc oxide nanoparticles could apparently decrease the plasma membrane calcium ATPase expression, inhibit their activity, cause the elevated intracellular calcium ion level and disrupt the intracellular calcium homeostasis. Further, the disrupted calcium homeostasis will trigger mitochondrial dysfunction, generate excessive reactive oxygen species, and finally initiate cell death. Thus, the disrupted calcium homeostasis is involved in the zinc oxide nanoparticle-induced rat retinal ganglion cell death. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Calcium supplementation decreases BCP-induced inflammatory processes in blood cells through the NLRP3 inflammasome down-regulation.

    PubMed

    Lagadec, Patricia; Balaguer, Thierry; Boukhechba, Florian; Michel, Grégory; Bouvet-Gerbettaz, Sébastien; Bouler, Jean-Michel; Scimeca, Jean-Claude; Rochet, Nathalie

    2017-07-15

    Interaction of host blood with biomaterials is the first event occurring after implantation in a bone defect. This study aimed at investigating the cellular and molecular consequences arising at the interface between whole blood and biphasic calcium phosphate (BCP) particles. We observed that, due to calcium capture, BCP inhibited blood coagulation, and that this inhibition was reversed by calcium supplementation. Therefore, we studied the impact of calcium supplementation on BCP effects on blood cells. Comparative analysis of BCP and calcium supplemented-BCP (BCP/Ca) effects on blood cells showed that BCP as well as BCP/Ca induced monocyte proliferation, as well as a weak but significant hemolysis. Our data showed for the first time that calcium supplementation of BCP microparticles had anti-inflammatory properties compared to BCP alone that induced an inflammatory response in blood cells. Our results strongly suggest that the anti-inflammatory property of calcium supplemented-BCP results from its down-modulating effect on P2X7R gene expression and its capacity to inhibit ATP/P2X7R interactions, decreasing the NLRP3 inflammasome activation. Considering that monocytes have a vast regenerative potential, and since the excessive inflammation often observed after bone substitutes implantation limits their performance, our results might have great implications in terms of understanding the mechanisms leading to an efficient bone reconstruction. Although scaffolds and biomaterials unavoidably come into direct contact with blood during bone defect filling, whole blood-biomaterials interactions have been poorly explored. By studying in 3D the interactions between biphasic calcium phosphate (BCP) in microparticulate form and blood, we showed for the first time that calcium supplementation of BCP microparticles (BCP/Ca) has anti-inflammatory properties compared to BCP-induced inflammation in whole blood cells and provided information related to the molecular mechanisms

  10. Kinetic Studies of Calcium-Induced Calcium Release in Cardiac Sarcoplasmic Reticulum Vesicles

    PubMed Central

    Sánchez, Gina; Hidalgo, Cecilia; Donoso, Paulina

    2003-01-01

    Fast Ca2+ release kinetics were measured in cardiac sarcoplasmic reticulum vesicles actively loaded with Ca2+. Release was induced in solutions containing 1.2 mM free ATP and variable free [Ca2+] and [Mg2+]. Release rate constants (k) were 10-fold higher at pCa 6 than at pCa 5 whereas Ryanodine binding was highest at pCa ≤5. These results suggest that channels respond differently when exposed to sudden [Ca2+] changes than when exposed to Ca2+ for longer periods. Vesicles with severalfold different luminal calcium contents exhibited double exponential release kinetics at pCa 6, suggesting that channels undergo time-dependent activity changes. Addition of Mg2+ produced a marked inhibition of release kinetics at pCa 6 (K0.5 = 63 μM) but not at pCa 5. Coexistence of calcium activation and inhibition sites with equally fast binding kinetics is proposed to explain this behavior. Thimerosal activated release kinetics at pCa 5 at all [Mg2+] tested and increased at pCa 6 the K0.5 for Mg2+ inhibition, from 63 μM to 136 μM. We discuss the possible relevance of these results, which suggest release through RyR2 channels is subject to fast regulation by Ca2+ and Mg2+ followed by time-dependent regulation, to the physiological mechanisms of cardiac channel opening and closing. PMID:12668440

  11. Calcium-induced conformational changes of Thrombospondin-1 signature domain: implications for vascular disease.

    PubMed

    Gupta, Akanksha; Agarwal, Rahul; Singh, Ashutosh; Bhatnagar, Sonika

    2017-06-01

    Thrombospondin1 (TSP1) participates in numerous signaling pathways critical for vascular physiology and disease. The conserved signature domain of thrombospondin 1 (TSP1-Sig1) comprises three epidermal growth factor (EGF), 13 calcium-binding type 3 thrombospondin (T3) repeats, and one lectin-like module arranged in a stalk-wire-globe topology. TSP1 is known to be present in both calcium-replete (Holo-) and calcium-depleted (Apo-) state, each with distinct downstream signaling effects. To prepare a homology model of TSP1-Sig1 and investigate the effect of calcium on its dynamic structure and interactions. A homology model of Holo-TSP1-Sig1 was prepared with TSP2 as template in Swissmodel workspace. The Apo-form of the model was obtained by omitting the bound calcium ions from the homology model. Molecular dynamics (MD) simulation studies (100 ns) were performed on the Holo- and Apo- forms of TSP1 using Gromacs4.6.5. After simulation, Holo-TSP1-Sig1 showed significant reorientation at the interface of the EGF1-2 and EGF2-3 modules. The T3 wire is predicted to show the maximum mobility and deviation from the initial model. In Apo-TSP1-Sig1 model, the T3 repeats unfolded and formed coils with predicted increase in flexibility. Apo-TSP1-Sig1model also predicted the exposure of the binding sites for neutrophil elastase, integrin and fibroblast growth factor 2. We present a structural model and hypothesis for the role of TSP1-Sig1 interactions in the development of vascular disorders. The simulated model of the fully calcium-loaded and calcium-depleted TSP1-Sig1 may enable the development of its interactions as a novel therapeutic target for the treatment of vascular diseases.

  12. Determining attitudinal and behavioral factors concerning milk and dairy intake and their association with calcium intake in college students

    PubMed Central

    2018-01-01

    BACKGROUND/OBJECTIVES Average intake of calcium among college students is below the recommended intake, and knowledge surrounding the attitudinal and behavioral factors that influence milk and dairy intake, a primary food source of calcium, is limited. The purpose of this study was to evaluate college students' attitudes and behaviors concerning milk and dairy consumption and their association with calcium intake. SUBJECTS/METHODS Participants were 1,730 undergraduate students who completed an online survey (SurveyMonkey) as part of baseline data collection for a social marketing dairy campaign. The online survey assessed attitudes and behaviors concerning milk and dairy intake, and calcium intake. Questions about milk- and dairy-related attitudes and behaviors were grouped into 14 factors using factor analysis. Predictors of calcium intake were then evaluated. RESULTS Median calcium intake across all participants was 928.6 mg/day, with males consuming higher calcium intakes than females (P < 0.001). Adjusted for gender, calcium intakes were most strongly (and positively) correlated with associating milk with specific eating occasions and availability (i.e., storing calcium-rich foods in one's dorm or apartment) (both P < 0.001). Other correlates of calcium intake included: positive-viewing milk as healthy (P = 0.039), having family members who drink milk) (P = 0.039), and taking calcium supplements (P = 0.056); and negative-parent rules concerning milk (P = 0.031) and viewing milk in dining halls negatively (P = 0.05). CONCLUSIONS Calcium intakes among college students enrolled in the current study was below the recommended dietary allowance of 1,000 mg/day, reinforcing the need for dietary interventions in this target population, especially females. Practitioners and researchers should consider the factors found here to impact calcium intake, particularly associating milk with specific eating occasions (e.g., milk with breakfast) and having calcium-rich foods

  13. Determining attitudinal and behavioral factors concerning milk and dairy intake and their association with calcium intake in college students.

    PubMed

    Rose, Angela M; Williams, Rachel A; Rengers, Brooke; Kennel, Julie A; Gunther, Carolyn

    2018-04-01

    Average intake of calcium among college students is below the recommended intake, and knowledge surrounding the attitudinal and behavioral factors that influence milk and dairy intake, a primary food source of calcium, is limited. The purpose of this study was to evaluate college students' attitudes and behaviors concerning milk and dairy consumption and their association with calcium intake. Participants were 1,730 undergraduate students who completed an online survey (SurveyMonkey) as part of baseline data collection for a social marketing dairy campaign. The online survey assessed attitudes and behaviors concerning milk and dairy intake, and calcium intake. Questions about milk- and dairy-related attitudes and behaviors were grouped into 14 factors using factor analysis. Predictors of calcium intake were then evaluated. Median calcium intake across all participants was 928.6 mg/day, with males consuming higher calcium intakes than females ( P < 0.001). Adjusted for gender, calcium intakes were most strongly (and positively) correlated with associating milk with specific eating occasions and availability (i.e., storing calcium-rich foods in one's dorm or apartment) (both P < 0.001). Other correlates of calcium intake included: positive-viewing milk as healthy ( P = 0.039), having family members who drink milk) ( P = 0.039), and taking calcium supplements ( P = 0.056); and negative-parent rules concerning milk ( P = 0.031) and viewing milk in dining halls negatively ( P = 0.05). Calcium intakes among college students enrolled in the current study was below the recommended dietary allowance of 1,000 mg/day, reinforcing the need for dietary interventions in this target population, especially females. Practitioners and researchers should consider the factors found here to impact calcium intake, particularly associating milk with specific eating occasions (e.g., milk with breakfast) and having calcium-rich foods available in the dorm room or apartment, as intervention

  14. Calcium metabolism and cardiovascular function after spaceflight

    NASA Technical Reports Server (NTRS)

    Hatton, Daniel C.; Yue, Qi; Dierickx, Jacqueline; Roullet, Chantal; Otsuka, Keiichi; Watanabe, Mitsuaki; Coste, Sarah; Roullet, Jean Baptiste; Phanouvang, Thongchan; Orwoll, Eric; hide

    2002-01-01

    To determine the influence of dietary calcium on spaceflight-induced alterations in calcium metabolism and blood pressure (BP), 9-wk-old spontaneously hypertensive rats, fed either high- (2%) or low-calcium (0.02%) diets, were flown on an 18-day shuttle flight. On landing, flight animals had increased ionized calcium (P < 0.001), elevated parathyroid hormone levels (P < 0.001), reduced calcitonin levels (P < 0.05), unchanged 1,25(OH)(2)D(3) levels, and elevated skull (P < 0.01) and reduced femur bone mineral density. Basal and thrombin-stimulated platelet free calcium (intracellular calcium concentration) were also reduced (P < 0.05). There was a tendency for indirect systolic BP to be reduced in conscious flight animals (P = 0.057). However, mean arterial pressure was elevated (P < 0.001) after anesthesia. Dietary calcium altered all aspects of calcium metabolism (P < 0.001), as well as BP (P < 0.001), but the only interaction with flight was a relatively greater increase in ionized calcium in flight animals fed low- compared with high-calcium diets (P < 0.05). The results indicate that 1) flight-induced disruptions of calcium metabolism are relatively impervious to dietary calcium in the short term, 2) increased ionized calcium did not normalize low-calcium-induced elevations of BP, and 3) parathyroid hormone was paradoxically increased in the high-calcium-fed flight animals after landing.

  15. xCT expression reduces the early cell cycle requirement for calcium signaling

    PubMed Central

    Lastro, Michele; Kourtidis, Antonis; Farley, Kate; Conklin, Douglas S.

    2009-01-01

    Calcium has long been recognized as an important regulator of cell cycle transitions although the mechanisms are largely unknown. A functional genomic screen has identified genes involved in the regulation of early cell cycle progression by calcium. These genes when overexpressed confer the ability to bypass the G1/S arrest induced by Ca2+- channel antagonists in mouse fibroblasts. Overexpression of the cystine-glutamate exchanger, xCT, had the greatest ability to evade calcium antagonist-induced cell cycle arrest. xCT carries out the rate limiting step of glutathione synthesis in many cell types and is responsible for the uptake of cystine in most human cancer cell lines. Functional analysis indicates that the cystine uptake activity of xCT overcomes the G1/S arrest induced by Ca2+- channel antagonists by bypassing the requirement for calcium signaling. Since cells overexpressing xCT were found to have increased levels and activity of the AP-1 transcription factor in G1, redox stimulation of AP-1 activity accounts for the observed growth of these cells in the presence of calcium channel antagonists. These results suggest that reduced calcium signaling impairs AP-1 activation and that xCT expression may directly affect cell proliferation. PMID:18054200

  16. Calcium-Induced Conformational Transition of Trout Ependymins Monitored by Tryptophan Fluorescence

    PubMed Central

    Ganss, Bernhard; Hoffmann, Werner

    2009-01-01

    Ependymins are secretory, calcium-binding sialoproteins which are the predominant constituents of the cerebrospinal fluid of many teleost fish. A bound form of these regeneration-responsive glycoproteins is associated with collagen fibrils of the extracellular matrix. Here, the tryptophan fluorescence of ependymins was monitored at various Ca2+ concentrations. Two distinct states were identified with a relatively sharp transition at about 1 mM Ca2+. In agreement with previous circular dichroism measurements, this strongly supports the hypothesis that a calcium-induced conformational change is important for the interaction of ependymins with components of the extracellular matrix. Such interactions with constituents of various basal laminae would also explain the important roles of piscine ependymins as well as invertebrate and mammalian ependymin-related proteins for cell adhesion processes and cell migration. PMID:19401757

  17. Calcium-induced conformational transition of trout ependymins monitored by tryptophan fluorescence.

    PubMed

    Ganss, Bernhard; Hoffmann, Werner

    2009-01-01

    Ependymins are secretory, calcium-binding sialoproteins which are the predominant constituents of the cerebrospinal fluid of many teleost fish. A bound form of these regeneration-responsive glycoproteins is associated with collagen fibrils of the extracellular matrix. Here, the tryptophan fluorescence of ependymins was monitored at various Ca(2+) concentrations. Two distinct states were identified with a relatively sharp transition at about 1 mM Ca(2+). In agreement with previous circular dichroism measurements, this strongly supports the hypothesis that a calcium-induced conformational change is important for the interaction of ependymins with components of the extracellular matrix. Such interactions with constituents of various basal laminae would also explain the important roles of piscine ependymins as well as invertebrate and mammalian ependymin-related proteins for cell adhesion processes and cell migration.

  18. Nonlinear Time Series Analysis of Nodulation Factor Induced Calcium Oscillations: Evidence for Deterministic Chaos?

    PubMed Central

    Hazledine, Saul; Sun, Jongho; Wysham, Derin; Downie, J. Allan; Oldroyd, Giles E. D.; Morris, Richard J.

    2009-01-01

    Legume plants form beneficial symbiotic interactions with nitrogen fixing bacteria (called rhizobia), with the rhizobia being accommodated in unique structures on the roots of the host plant. The legume/rhizobial symbiosis is responsible for a significant proportion of the global biologically available nitrogen. The initiation of this symbiosis is governed by a characteristic calcium oscillation within the plant root hair cells and this signal is activated by the rhizobia. Recent analyses on calcium time series data have suggested that stochastic effects have a large role to play in defining the nature of the oscillations. The use of multiple nonlinear time series techniques, however, suggests an alternative interpretation, namely deterministic chaos. We provide an extensive, nonlinear time series analysis on the nature of this calcium oscillation response. We build up evidence through a series of techniques that test for determinism, quantify linear and nonlinear components, and measure the local divergence of the system. Chaos is common in nature and it seems plausible that properties of chaotic dynamics might be exploited by biological systems to control processes within the cell. Systems possessing chaotic control mechanisms are more robust in the sense that the enhanced flexibility allows more rapid response to environmental changes with less energetic costs. The desired behaviour could be most efficiently targeted in this manner, supporting some intriguing speculations about nonlinear mechanisms in biological signaling. PMID:19675679

  19. [Intracellular free calcium changes of mouse oocytes during activation induced by ethanol or electrical stimulations and parthenogenetic development].

    PubMed

    Deng, M Q; Fan, B Q

    1994-09-01

    Oocytes collected 18-19 h after HCG injection were stimulated with 7-8% ethanol or electrical pulses (1.7 KV/cm field strength, 80-100 microseconds duration, 3-4 times, 5-6 min interval). The parthenogenetic embryos derived from the above-mentioned methods developed to blastocyst stage just like those developed from fertilized eggs. Mouse oocytes were rather sensitive to ethanol stimulation. More than 95% of the treated oocytes were activated after stimulation of 7-8% ethanol for 5 min. Multiple electrical stimulations induced higher activation percentages of oocytes than only single electrical stimulation (71.5% vs. 63.6%). Intact oocytes were loaded with fluorescent Ca2+ indicator fura-2 and intracellular free calcium changes during artificial activation were measured by fluorescence detector. The results showed that ethanol could induce repetitive transient Ca2+ concentration increase in activated oocytes. Single electrical stimulation only induced single free calcium concentration elevation in oocyte while multiple electrical pulses could induce repetitive Ca2+ increase (each electrical pulse elicited the corresponding Ca2+ concentration peak). The pronuclei were not observed in the oocytes which had not exhibited calcium concentration rise during activation. Apart from electrical stimulation parameter, sufficient amount of Ca2+ in electric medium was crucial to mouse oocyte activation when stimulated with electrical pulses. The oocytes were hardly activated by electrical stimulations in a medium without Ca2+ even with longer pulse duration and the intracellular free calcium concentration in the oocytes showed no elevation. This indicates that the inflow of extracellular Ca2+ from tiny pores across the oocyte membrane caused by electrical stimulation is the main source of intracellular free calcium increase.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Pseudomonas, Pantoea and Cupriavidus isolates induce calcium carbonate precipitation for biorestoration of ornamental stone.

    PubMed

    Daskalakis, M I; Magoulas, A; Kotoulas, G; Catsikis, I; Bakolas, A; Karageorgis, A P; Mavridou, A; Doulia, D; Rigas, F

    2013-08-01

    Bacterially induced calcium carbonate precipitation from various isolates was investigated aiming at developing an environmentally friendly technique for ornamental stone protection and restoration. Micro-organisms isolated from stone samples and identified using 16S rDNA and biochemical tests promoted calcium carbonate precipitation in solid and novel liquid growth media. Biomineral morphology was studied on marble samples with scanning electron microscopy. Most isolates demonstrated specimen weight increase, covering partially or even completely the marble surfaces mainly with vaterite. The conditions under which vaterite precipitated and its stability throughout the experimental runs are presented. A growth medium that facilitated bacterial growth of different species and promoted biomineralization was formulated. Most isolates induced biomineralization of CaCO3 . Micro-organisms may actually be a milestone in the investigation of vaterite formation facilitating our understanding of geomicrobiological interactions. Pseudomonas, Pantoea and Cupriavidus strains could be candidates for bioconsolidation of ornamental stone protection. Characterization of biomineralization capacity of different bacterial species improves understanding of the bacterially induced mineralization processes and enriches the list of candidates for biorestoration applications. Knowledge of biomineral morphology assists in differentiating mineral from biologically induced precipitates. © 2013 The Society for Applied Microbiology.

  1. Calcium: A novel and efficient inducer of differentiation of adipose-derived stem cells into neuron-like cells.

    PubMed

    Goudarzi, Farjam; Tayebinia, Heidar; Karimi, Jamshid; Habibitabar, Elahe; Khodadadi, Iraj

    2018-06-05

    This study comparatively investigated the effectiveness of calcium and other well-known inducers such as isobutylmethylxanthine (IBMX) and insulin in differentiating human adipose-derived stem cells (ADSCs) into neuronal-like cells. ADSCs were immunophenotyped and differentiated into neuron-like cells with different combinations of calcium, IBMX, and insulin. Calcium mobilization across the membrane was determined. Differentiated cells were characterized by cell cycle profiling, staining of Nissl bodies, detecting the gene expression level of markers such as neuronal nuclear antigen (NeuN), microtubule associated protein 2 (MAP2), neuron-specific enolase (NSE), doublecortin, synapsin I, glial fibrillary acidic protein (GFAP), and myelin basic protein (MBP) by quantitative real-time polymerase chain reaction (quantitative real-time polymerase chain reaction (qRT-PCR) and protein level by the immunofluorescence technique. Treatment with Ca + IBMX + Ins induced neuronal appearance and projection of neurite-like processes in the cells, accompanied with inhibition of proliferation and halt in the cell cycle. A significantly higher expression of MBP, GFAP, NeuN, NSE, synapsin 1, doublecortin, and MAP2 was detected in differentiated cells, confirming the advantages of Ca + IBMX + Ins to the other combinations of inducers. Here, we showed an efficient protocol for neuronal differentiation of ADSCs, and calcium fostered differentiation by augmenting the number of neuron-like cells and instantaneous increase in the expression of neuronal markers. © 2018 Wiley Periodicals, Inc.

  2. Blocking Cyclic Adenosine Diphosphate Ribose-mediated Calcium Overload Attenuates Sepsis-induced Acute Lung Injury in Rats

    PubMed Central

    Peng, Qian-Yi; Zou, Yu; Zhang, Li-Na; Ai, Mei-Lin; Liu, Wei; Ai, Yu-Hang

    2016-01-01

    Background: Acute lung injury (ALI) is a common complication of sepsis that is associated with high mortality. Intracellular Ca2+ overload plays an important role in the pathophysiology of sepsis-induced ALI, and cyclic adenosine diphosphate ribose (cADPR) is an important regulator of intracellular Ca2+ mobilization. The cluster of differentiation 38 (CD38)/cADPR pathway has been found to play roles in multiple inflammatory processes but its role in sepsis-induced ALI is still unknown. This study aimed to investigate whether the CD38/cADPR signaling pathway is activated in sepsis-induced ALI and whether blocking cADPR-mediated calcium overload attenuates ALI. Methods: Septic rat models were established by cecal ligation and puncture (CLP). Rats were divided into the sham group, the CLP group, and the CLP+ 8-bromo-cyclic adenosine diphosphate ribose (8-Br-cADPR) group. Nicotinamide adenine dinucleotide (NAD+), cADPR, CD38, and intracellular Ca2+ levels in the lung tissues were measured at 6, 12, 24, and 48 h after CLP surgery. Lung histologic injury, tumor necrosis factor (TNF)-α, malondialdehyde (MDA) levels, and superoxide dismutase (SOD) activities were measured. Results: NAD+, cADPR, CD38, and intracellular Ca2+ levels in the lungs of septic rats increased significantly at 24 h after CLP surgery. Treatment with 8-Br-cADPR, a specific inhibitor of cADPR, significantly reduced intracellular Ca2+ levels (P = 0.007), attenuated lung histological injury (P = 0.023), reduced TNF-α and MDA levels (P < 0.001 and P = 0.002, respectively) and recovered SOD activity (P = 0.031) in the lungs of septic rats. Conclusions: The CD38/cADPR pathway is activated in the lungs of septic rats, and blocking cADPR-mediated calcium overload with 8-Br-cADPR protects against sepsis-induced ALI. PMID:27411462

  3. Alcohol enhances oxysterol-induced apoptosis in human endothelial cells by a calcium-dependent mechanism.

    PubMed

    Spyridopoulos, I; Wischhusen, J; Rabenstein, B; Mayer, P; Axel, D I; Fröhlich, K U; Karsch, K R

    2001-03-01

    Controversy exists about the net effect of alcohol on atherogenesis. A protective effect is assumed, especially from the tannins and phenolic compounds in red wine, owing to their inhibition of low density lipoprotein (LDL) oxidation. However, increased atherogenesis occurs in subjects with moderate to heavy drinking habits. The purpose of this study was to investigate the influence of alcohol in combination with oxysterols on the endothelium. Cultured human arterial endothelial cells (HAECs) served as an in vitro model to test the cellular effects of various oxysterols. Oxysterols (7beta-hydroxycholesterol, 7-ketocholesterol, and cholesterol-5,6-epoxides), which are assumed to be the most toxic constituents of oxidized LDL, induced apoptosis in HAECs through calcium mobilization followed by activation of caspase-3. Ethanol, methanol, isopropanol, tert-butanol, and red wine all potentiated oxysterol-induced cell death up to 5-fold, paralleled by further induction of caspase-3. The alcohol effect occurred in a dose-dependent manner and reached a plateau at 0.05% concentration. Alcohol itself did not affect endothelial cell viability, nor did other solvents such as dimethyl sulfoxide mimic the alcohol effect. So far as the physiologically occurring oxysterols are concerned, this effect was apparent only for oxysterols oxidized at the steran ring. The possibility of alcohol facilitating the uptake of oxysterols into the cell was not supported by the data from an uptake study with radiolabeled compounds. Finally, alcohol in combination with oxysterols did cause a dramatic increase in cytosolic calcium influx. Blockage of calcium influx by the calcium channel blocker aurintricarboxylic acid or the calcium chelator ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid abrogated the alcohol-mediated enhancement of oxysterol toxicity. We describe for the first time a mechanistic concept explaining possible adverse effects of alcohol in conjunction with

  4. On the effect of the injection of potassium phosphate in vivo inducing the precipitation of serum calcium with inorganic phosphate

    PubMed Central

    Soares, Alcimar B; Ticianeli, José G; Soares, Letícia B M; Amaro, George

    2013-01-01

    High concentrations of inorganic phosphate (Pi) resulted from the hydrolysis of ATP is strongly associated to the weakness of the contractile mechanism of muscles due to its attractiveness to calcium. The majority of the experiments to study such effect are conducted in vitro. This work investigates the effects of different concentrations of Pi, induced by the injection of potassium phosphate in live animals, in the precipitation with serum calcium and the generation of calcium phosphate composites. The experiments were also designed to find out the ideal amount of potassium phosphate to induce an effective reaction. Potassium phosphate was injected in Wistar rats, randomly separated and distributed into seven groups. Group I was injected with 0.5 ml of saline solution (control) and groups II through VII were injected with 0.5, 1.5, 2.5, 5.0, 7.5 and 10.0 mg/kg of potassium phosphate, respectively. Blood collected from the inferior vena cava was submitted to biochemical analyses to measure the concentrations of calcium, Pi, urea and creatinine. The results showed that Pi, induced by the injection of potassium phosphate in live animals, causes precipitation with serum calcium, with statistically significant differences between the control and the treatment groups for doses up to 5.0 mg/kg. No statistically significant differences were found between the different doses and the concentration of urea and creatinine in the plasma. We conclude that potassium phosphate can be used to induce serum calcium precipitation in-vivo, with minor effects on other physiological variables, and the ideal dose to do so is 5.0 mg/kg. PMID:24379908

  5. Role of the JAKs/STATs pathway in the intracellular calcium changes induced by interleukin-6 in hippocampal neurons.

    PubMed

    Orellana, D I; Quintanilla, R A; Gonzalez-Billault, C; Maccioni, R B

    2005-11-01

    Recent studies show that inflammation has an active role in the onset of neurodegenerative diseases. It is known that in response to extracellular insults microglia and/or astrocytes produce inflammatory agents. These contribute to the neuropathological events in the aging process and neuronal degeneration. Interleukin-6 (IL-6) has been involved in the pathogenesis of neurodegenerative disorders, such as Alzheimer's and Parkinson's diseases. Here, we show that IL-6 treatment of rat hippocampal neurons increases the calcium influx via NMDA-receptor, an effect that is prevented by the specific NMDA receptor antagonist MK-801 (dizocilpine). We also show that this calcium influx is mediated by the JAKs/STATs pathway, since the inhibitor of JAKs/STATs pathway, JAK 3 inhibitor, blocks calcium influx even in the presence of IL-6. This increase in calcium signal was dependent on external sources, since this signal was not observed in the presence of EGTA. Additional studies indicate that the increase in cytosolic calcium induces tau protein hyperphosphorylation, as revealed by using specific antibodies against Alzheimer phosphoepitopes. This anomalous tau hyperphosphorylation was dependent on both the JAKs/STATs pathway and NMDA receptor. These results suggest that IL-6 would induce a cascade of molecular events that produce a calcium influx through NMDA receptors, mediated by the JAKs/STATs pathway, which subsequently modifies the tau hyperphosphorylation patterns.

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

    PubMed

    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.

  7. Extracellular calcium antagonizes forskolin-induced aquaporin 2 trafficking in collecting duct cells.

    PubMed

    Procino, Giuseppe; Carmosino, Monica; Tamma, Grazia; Gouraud, Sabine; Laera, Antonia; Riccardi, Daniela; Svelto, Maria; Valenti, Giovanna

    2004-12-01

    Urinary concentrating defects and polyuria are the most important renal manifestations of hypercalcemia and the resulting hypercalciuria. In this study, we tested the hypothesis that hypercalciuria-associated polyuria in kidney collecting duct occurs through an impairment of the vasopressin-dependent aquaporin 2 (AQP2) water channel targeting to the apical membrane possibly involving calcium-sensing receptor (CaR) signaling. AQP2-transfected collecting duct CD8 cells were used as experimental model. Quantitation of cell surface AQP2 immunoreactivity was performed using an antibody recognizing the extracellular AQP2 C loop. Intracellular cyclic adenosine monophosphate (cAMP) accumulation was measured in CD8 cells using a cAMP enzyme immunoassay kit. To study the translocation of protein kinase C (PKC), membranes or cytosol fractions from CD8 cells were subjected to Western blotting using anti-PKC isozymes antibodies. The amount of F-actin was determined by spectrofluorometric techniques. Intracellular calcium measurements were performed by spectrofluorometric analysis with Fura-2/AM. We demonstrated that extracellular calcium (Ca2+ o) (5 mmol/L) strongly inhibited forskolin-stimulated increase in AQP2 expression in the apical plasma membrane. At least three intracellular pathways activated by extracellular calcium were found to contribute to this effect. Firstly, the increase in cAMP levels in response to forskolin stimulation was drastically reduced in cells pretreated with Ca2+ o compared to untreated cells. Second, Ca2+ o activated PKC, known to counteract vasopressin response. Third, quantification of F-actin demonstrated that Ca2+ o caused a nearly twofold increase in F-actin content compared with basal conditions. All these effects were mimicked by a nonmembrane permeable agonist of the extracellular CaR, Gd3+. Together, these data demonstrate that extracellular calcium, possibly acting through the endogenous CaR, antagonizes forskolin-induced AQP2

  8. Direct Imaging of ER Calcium with Targeted-Esterase Induced Dye Loading (TED)

    PubMed Central

    Samtleben, Samira; Jaepel, Juliane; Fecher, Caroline; Andreska, Thomas; Rehberg, Markus; Blum, Robert

    2013-01-01

    Visualization of calcium dynamics is important to understand the role of calcium in cell physiology. To examine calcium dynamics, synthetic fluorescent Ca2+ indictors have become popular. Here we demonstrate TED (= targeted-esterase induced dye loading), a method to improve the release of Ca2+ indicator dyes in the ER lumen of different cell types. To date, TED was used in cell lines, glial cells, and neurons in vitro. TED bases on efficient, recombinant targeting of a high carboxylesterase activity to the ER lumen using vector-constructs that express Carboxylesterases (CES). The latest TED vectors contain a core element of CES2 fused to a red fluorescent protein, thus enabling simultaneous two-color imaging. The dynamics of free calcium in the ER are imaged in one color, while the corresponding ER structure appears in red. At the beginning of the procedure, cells are transduced with a lentivirus. Subsequently, the infected cells are seeded on coverslips to finally enable live cell imaging. Then, living cells are incubated with the acetoxymethyl ester (AM-ester) form of low-affinity Ca2+ indicators, for instance Fluo5N-AM, Mag-Fluo4-AM, or Mag-Fura2-AM. The esterase activity in the ER cleaves off hydrophobic side chains from the AM form of the Ca2+ indicator and a hydrophilic fluorescent dye/Ca2+ complex is formed and trapped in the ER lumen. After dye loading, the cells are analyzed at an inverted confocal laser scanning microscope. Cells are continuously perfused with Ringer-like solutions and the ER calcium dynamics are directly visualized by time-lapse imaging. Calcium release from the ER is identified by a decrease in fluorescence intensity in regions of interest, whereas the refilling of the ER calcium store produces an increase in fluorescence intensity. Finally, the change in fluorescent intensity over time is determined by calculation of ΔF/F0. PMID:23685703

  9. Direct imaging of ER calcium with targeted-esterase induced dye loading (TED).

    PubMed

    Samtleben, Samira; Jaepel, Juliane; Fecher, Caroline; Andreska, Thomas; Rehberg, Markus; Blum, Robert

    2013-05-07

    Visualization of calcium dynamics is important to understand the role of calcium in cell physiology. To examine calcium dynamics, synthetic fluorescent Ca(2+) indictors have become popular. Here we demonstrate TED (= targeted-esterase induced dye loading), a method to improve the release of Ca(2+) indicator dyes in the ER lumen of different cell types. To date, TED was used in cell lines, glial cells, and neurons in vitro. TED bases on efficient, recombinant targeting of a high carboxylesterase activity to the ER lumen using vector-constructs that express Carboxylesterases (CES). The latest TED vectors contain a core element of CES2 fused to a red fluorescent protein, thus enabling simultaneous two-color imaging. The dynamics of free calcium in the ER are imaged in one color, while the corresponding ER structure appears in red. At the beginning of the procedure, cells are transduced with a lentivirus. Subsequently, the infected cells are seeded on coverslips to finally enable live cell imaging. Then, living cells are incubated with the acetoxymethyl ester (AM-ester) form of low-affinity Ca(2+) indicators, for instance Fluo5N-AM, Mag-Fluo4-AM, or Mag-Fura2-AM. The esterase activity in the ER cleaves off hydrophobic side chains from the AM form of the Ca(2+) indicator and a hydrophilic fluorescent dye/Ca(2+) complex is formed and trapped in the ER lumen. After dye loading, the cells are analyzed at an inverted confocal laser scanning microscope. Cells are continuously perfused with Ringer-like solutions and the ER calcium dynamics are directly visualized by time-lapse imaging. Calcium release from the ER is identified by a decrease in fluorescence intensity in regions of interest, whereas the refilling of the ER calcium store produces an increase in fluorescence intensity. Finally, the change in fluorescent intensity over time is determined by calculation of ΔF/F0.

  10. Hydrogen sulfide-induced itch requires activation of Cav3.2 T-type calcium channel in mice

    PubMed Central

    Wang, Xue-Long; Tian, Bin; Huang, Ya; Peng, Xiao-Yan; Chen, Li-Hua; Li, Jun-Cheng; Liu, Tong

    2015-01-01

    The contributions of gasotransmitters to itch sensation are largely unknown. In this study, we aimed to investigate the roles of hydrogen sulfide (H2S), a ubiquitous gasotransmitter, in itch signaling. We found that intradermal injection of H2S donors NaHS or Na2S, but not GYY4137 (a slow-releasing H2S donor), dose-dependently induced scratching behavior in a μ-opioid receptor-dependent and histamine-independent manner in mice. Interestingly, NaHS induced itch via unique mechanisms that involved capsaicin-insensitive A-fibers, but not TRPV1-expressing C-fibers that are traditionally considered for mediating itch, revealed by depletion of TRPV1-expressing C-fibers by systemic resiniferatoxin treatment. Moreover, local application of capsaizapine (TRPV1 blocker) or HC-030031 (TRPA1 blocker) had no effects on NaHS-evoked scratching. Strikingly, pharmacological blockade and silencing of Cav3.2 T-type calcium channel by mibefradil, ascorbic acid, zinc chloride or Cav3.2 siRNA dramatically decreased NaHS-evoked scratching. NaHS induced robust alloknesis (touch-evoked itch), which was inhibited by T-type calcium channels blocker mibefradil. Compound 48/80-induced itch was enhanced by an endogenous precursor of H2S (L-cysteine) but attenuated by inhibitors of H2S-producing enzymes cystathionine γ-lyase and cystathionine β-synthase. These results indicated that H2S, as a novel nonhistaminergic itch mediator, may activates Cav3.2 T-type calcium channel, probably located at A-fibers, to induce scratching and alloknesis in mice. PMID:26602811

  11. The role of calcium in osteoporosis.

    PubMed

    Arnaud, C D; Sanchez, S D

    1990-01-01

    Calcium requirements may vary throughout the lifespan. During the growth years and up to age 25-30, it is important to maximize dietary intake of calcium to maintain positive calcium balance and achieve peak bone mass, thereby possibly decreasing the risk of fracture when bone is subsequently lost. The RDA for age 10-25 is 1200 mg/day. Calcium intake need not be greater than 800 mg/day during the relatively short period of time between the end of bone building and the onset of bone loss (30 to 40 years old). Starting at age 40-45, both men and women lose bone slowly, but women lose bone more rapidly around the menopause and for about 10 years after. Intestinal calcium absorption and the ability to adapt to low calcium diets are impaired in many postmenopausal women and elderly persons owing to a suspected functional or absolute decrease in the ability of the kidney to produce 1,25(OH)2D3. The bones then become more and more a source of calcium to maintain critical extracellular fluid calcium levels. Available evidence suggests that the impairments of intestinal calcium absorption observed during the menopause and aging can be overcome only by inordinately large calcium intakes (1500 to 2500 mg/day). Since this amount is difficult to derive from the diet, can cause constipation, and may not prevent trabecular bone loss, it should not be used as a substitute for sex hormone replacement. Women taking estrogen replacement should be provided the RDA for calcium of 800 mg/day at a minimum. Those who cannot or will not take estrogen should be asked to ingest at least 1000 to 1500 mg/day of calcium to delay cortical bone loss and prevent secondary hyperparathyroidism. It should be emphasized that up to 2000 mg/day of calcium is safe in teenaged children and adults. Excessive dietary intake of protein and fiber may induce significant negative calcium balance and thus increase dietary calcium requirements. It is also possible that excessive intakes of phosphate could have a

  12. Calcium Hydroxide-induced Proliferation, Migration, Osteogenic Differentiation, and Mineralization via the Mitogen-activated Protein Kinase Pathway in Human Dental Pulp Stem Cells.

    PubMed

    Chen, Luoping; Zheng, Lisha; Jiang, Jingyi; Gui, Jinpeng; Zhang, Lingyu; Huang, Yan; Chen, Xiaofang; Ji, Jing; Fan, Yubo

    2016-09-01

    Calcium hydroxide has been extensively used as the gold standard for direct pulp capping in clinical dentistry. It induces proliferation, migration, and mineralization in dental pulp stem cells (DPSCs), but the underlying mechanisms are still unclear. The aim of this study was to investigate the role of the mitogen-activated protein (MAP) kinase pathway in calcium hydroxide-induced proliferation, migration, osteogenic differentiation, and mineralization in human DPSCs. Human DPSCs between passages 3 and 6 were used. DPSCs were preincubated with inhibitors of MAP kinases and cultured with calcium hydroxide. The phosphorylated MAP kinases were detected by Western blot analysis. Cell viability was analyzed via the methylthiazol tetrazolium assay. Cell migration was estimated using the wound healing assay. Alkaline phosphatase (ALP) expression was analyzed using the ALP staining assay. Mineralization was studied by alizarin red staining analysis. Calcium hydroxide significantly promoted the phosphorylation of the c-Jun N-terminal kinase (JNK), p38, and extracellular signal-regulated kinase. The inhibition of JNK and p38 signaling abolished calcium hydroxide-induced proliferation of DPSCs. The inhibition of JNK, p38, and extracellular signal-regulated kinase signaling suppressed the migration, ALP expression, and mineralization of DPSCs. Our study showed that the MAP kinase pathway was involved in calcium hydroxide-induced proliferation, migration, osteogenic differentiation, and mineralization in human DPSCs. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  13. The effects of crustacean cardioactive peptide on locust oviducts are calcium-dependent.

    PubMed

    Donini, Andrew; Lange, Angela B

    2002-04-01

    The role of calcium as a second messenger in the crustacean cardioactive peptide (CCAP)-induced contractions of the locust oviducts was investigated. Incubation of the oviducts in a calcium-free saline containing, a preferential calcium cation chelator, or an extracellular calcium channel blocker, abolished CCAP-induced contractions, indicating that the effects of CCAP on the oviducts are calcium-dependent. In contrast, sodium free saline did not affect CCAP-induced contractions. Co-application of CCAP to the oviducts with preferential L-type voltage-dependent calcium channel blockers reduced CCAP-induced contractions by 32-54%. Two preferential T-type voltage-dependent calcium channel blockers both inhibited CCAP-induced oviduct contractions although affecting different components of the contractions. Amiloride decreased the tonic component of CCAP-induced contractions by 40-55% and flunarizine dihydrochloride decreased the frequency of CCAP-induced phasic contractions by as much as 65%, without affecting tonus. Flunarizine dihydrochloride did not alter the proctolin-induced contractions of the oviducts. Results suggest that the actions of CCAP are partially mediated by voltage-dependent calcium channels similar to vertebrate L-type and T-type channels. High-potassium saline does not abolish CCAP-induced contractions indicating the presence of receptor-operated calcium channels that mediate the actions of CCAP on the oviducts. The involvement of calcium from intracellular stores in CCAP-induced contractions of the oviducts is likely since, an intracellular calcium antagonist decreased CCAP-induced contractions by 30-35%.

  14. The interplay between HIF-1 and calcium signalling in cancer.

    PubMed

    Azimi, Iman

    2018-04-01

    The interplay between hypoxia-inducible factor-1 (HIF-1) and calcium in cancer has begun to be unravelled with recent findings demonstrating the relationships between the two in different cancer types. This is an area of significance considering the crucial roles of both HIF-1 and calcium signalling in cancer progression and metastasis. This review summarises the experimental evidence of the crosstalk between HIF-1 and specific calcium channels, pumps and regulators in the context of cancer. HIF-1 as a master regulator of hypoxic transcriptional responses, mediates transcription of several calcium modulators. On the other hand, specific calcium channels and pumps regulate HIF-1 activity through controlling its transcription, translation, stabilisation, or nuclear translocation. Identifying the interplay between HIF-1 and components of the calcium signal will give new insights into mechanisms underlying cellular responses to physiological and pathophysiological cues, and may provide novel and more efficient therapeutic strategies for the control of cancer progression. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Alleviation of ascorbic acid-induced gastric high acidity by calcium ascorbate in vitro and in vivo.

    PubMed

    Lee, Joon-Kyung; Jung, Sang-Hyuk; Lee, Sang-Eun; Han, Joo-Hui; Jo, Eunji; Park, Hyun-Soo; Heo, Kyung-Sun; Kim, Deasun; Park, Jeong-Sook; Myung, Chang-Seon

    2018-01-01

    Ascorbic acid is one of the most well-known nutritional supplement and antioxidant found in fruits and vegetables. Calcium ascorbate has been developed to mitigate the gastric irritation caused by the acidity of ascorbic acid. The aim of this study was to compare calcium ascorbate and ascorbic acid, focusing on their antioxidant activity and effects on gastric juice pH, total acid output, and pepsin secretion in an in vivo rat model, as well as pharmacokinetic parameters. Calcium ascorbate and ascorbic acid had similar antioxidant activity. However, the gastric fluid pH was increased by calcium ascorbate, whereas total acid output was increased by ascorbic acid. In the rat pylorus ligation-induced ulcer model, calcium ascorbate increased the gastric fluid pH without changing the total acid output. Administration of calcium ascorbate to rats given a single oral dose of 100 mg/kg as ascorbic acid resulted in higher plasma concentrations than that from ascorbic acid alone. The area under the curve (AUC) values of calcium ascorbate were 1.5-fold higher than those of ascorbic acid, and the C max value of calcium ascorbate (91.0 ng/ml) was higher than that of ascorbic acid (74.8 ng/ml). However, their T max values were similar. Thus, although calcium ascorbate showed equivalent antioxidant activity to ascorbic acid, it could attenuate the gastric high acidity caused by ascorbic acid, making it suitable for consideration of use to improve the side effects of ascorbic acid. Furthermore, calcium ascorbate could be an appropriate antioxidant substrate, with increased oral bioavailability, for patients with gastrointestinal disorders.

  16. Alleviation of ascorbic acid-induced gastric high acidity by calcium ascorbate in vitro and in vivo

    PubMed Central

    Lee, Joon-Kyung; Jung, Sang-Hyuk; Lee, Sang-Eun; Han, Joo-Hui; Jo, Eunji; Park, Hyun-Soo; Heo, Kyung-Sun; Kim, Deasun

    2018-01-01

    Ascorbic acid is one of the most well-known nutritional supplement and antioxidant found in fruits and vegetables. Calcium ascorbate has been developed to mitigate the gastric irritation caused by the acidity of ascorbic acid. The aim of this study was to compare calcium ascorbate and ascorbic acid, focusing on their antioxidant activity and effects on gastric juice pH, total acid output, and pepsin secretion in an in vivo rat model, as well as pharmacokinetic parameters. Calcium ascorbate and ascorbic acid had similar antioxidant activity. However, the gastric fluid pH was increased by calcium ascorbate, whereas total acid output was increased by ascorbic acid. In the rat pylorus ligation-induced ulcer model, calcium ascorbate increased the gastric fluid pH without changing the total acid output. Administration of calcium ascorbate to rats given a single oral dose of 100 mg/kg as ascorbic acid resulted in higher plasma concentrations than that from ascorbic acid alone. The area under the curve (AUC) values of calcium ascorbate were 1.5-fold higher than those of ascorbic acid, and the Cmax value of calcium ascorbate (91.0 ng/ml) was higher than that of ascorbic acid (74.8 ng/ml). However, their Tmax values were similar. Thus, although calcium ascorbate showed equivalent antioxidant activity to ascorbic acid, it could attenuate the gastric high acidity caused by ascorbic acid, making it suitable for consideration of use to improve the side effects of ascorbic acid. Furthermore, calcium ascorbate could be an appropriate antioxidant substrate, with increased oral bioavailability, for patients with gastrointestinal disorders. PMID:29302210

  17. A light- and calcium-gated transcription factor for imaging and manipulating activated neurons

    PubMed Central

    Wang, W.; Wildes, C. P.; Pattarabanjird, T.; Sanchez, M. I.; Glober, G.F.; Matthews, G. A.; Tye, K. M.; Ting, A. Y

    2017-01-01

    Activity remodels neurons, altering their molecular, structural, and electrical characteristics. To enable the selective characterization and manipulation of these neurons, we present FLARE, an engineered transcription factor that drives expression of fluorescent proteins, opsins, and other genetically-encoded tools only in the subset of neurons that experienced activity during a user-defined time window. FLARE senses the coincidence of elevated cytosolic calcium and externally-applied blue light, which together produce translocation of a membrane-anchored transcription factor to the nucleus to drive expression of any transgene. In cultured rat neurons, FLARE gives a light-to-dark signal ratio of 120 and a high-to-low calcium signal ratio of 10 after 10 minutes of stimulation. Channelrhodopsin expression permitted functional manipulation of FLARE-marked neurons. In adult mice, FLARE also gave light- and motor activity-dependent transcription in the cortex. Due to its modular design, minute-scale temporal resolution, and minimal dark-state leak, FLARE should be useful for the study of activity-dependent processes in neurons and other cells that signal with calcium. PMID:28650461

  18. A light- and calcium-gated transcription factor for imaging and manipulating activated neurons.

    PubMed

    Wang, Wenjing; Wildes, Craig P; Pattarabanjird, Tanyaporn; Sanchez, Mateo I; Glober, Gordon F; Matthews, Gillian A; Tye, Kay M; Ting, Alice Y

    2017-09-01

    Activity remodels neurons, altering their molecular, structural, and electrical characteristics. To enable the selective characterization and manipulation of these neurons, we present FLARE, an engineered transcription factor that drives expression of fluorescent proteins, opsins, and other genetically encoded tools only in the subset of neurons that experienced activity during a user-defined time window. FLARE senses the coincidence of elevated cytosolic calcium and externally applied blue light, which together produce translocation of a membrane-anchored transcription factor to the nucleus to drive expression of any transgene. In cultured rat neurons, FLARE gives a light-to-dark signal ratio of 120 and a high- to low-calcium signal ratio of 10 after 10 min of stimulation. Opsin expression permitted functional manipulation of FLARE-marked neurons. In adult mice, FLARE also gave light- and motor-activity-dependent transcription in the cortex. Due to its modular design, minute-scale temporal resolution, and minimal dark-state leak, FLARE should be useful for the study of activity-dependent processes in neurons and other cells that signal with calcium.

  19. Dysregulation of cellular calcium homeostasis in Alzheimer's disease: bad genes and bad habits.

    PubMed

    Mattson, M P; Chan, S L

    2001-10-01

    Calcium is one of the most important intracellular messengers in the brain, being essential for neuronal development, synaptic transmission and plasticity, and the regulation of various metabolic pathways. The findings reviewed in the present article suggest that calcium also plays a prominent role in the pathogenesis of Alzheimer's disease (AD). Associations between the pathological hallmarks ofAD (neurofibrillary tangles [NFT] and amyloid plaques) and perturbed cellular calcium homeostasis have been established in studies of patients, and in animal and cell culture models of AD. Studies of the effects of mutations in the beta-amyloid precursor protein (APP) and presenilins on neuronal plasticity and survival have provided insight into the molecular cascades that result in synaptic dysfunction and neuronal degeneration in AD. Central to the neurodegenerative process is the inability of neurons to properly regulate intracellular calcium levels. Increased levels of amyloid beta-peptide (Abeta) induce oxidative stress, which impairs cellular ion homeostasis and energy metabolism and renders neurons vulnerable to apoptosis and excitotoxicity. Subtoxic levels of Abeta may induce synaptic dysfunction by impairing multiple signal transduction pathways. Presenilin mutations perturb calcium homeostasis in the endoplasmic reticulum in a way that sensitizes neurons to apoptosis and excitotoxicity; links between aberrant calcium regulation and altered APP processing are emerging. Environmental risk factors for AD are being identified and may include high calorie diets, folic acid insufficiency, and a low level of intellectual activity (bad habits); in each case, the environmental factor impacts on neuronal calcium homeostasis. Low calorie diets and intellectual activity may guard against AD by stimulating production of neurotrophic factors and chaperone proteins. The emerging picture of the cell and molecular biology of AD is revealing novel preventative and therapeutic

  20. Effect of Topical Calcium Channel Blockers on Intraocular Pressure in Steroid-induced Glaucoma.

    PubMed

    Ganekal, Sunil; Dorairaj, Syril; Jhanji, Vishal; Kudlu, Krishnaprasad

    2014-01-01

    To evaluate the effect of 0.125% verapamil and 0.5% diltiazem eye drops on intraocular pressure (IOP) in steroid-induced glaucoma in rabbit eyes. A total of 18 rabbits with steroid-induced glaucoma were divided into three groups (A, B and C; n = 6 each). Right eyes in groups A, B and C received 0.5% diltiazem, 0.125% verapamil and 0.5% timolol eye drops twice daily for 12 days, respectively; whereas, left eyes received distilled water. IOP was measured with Tono-pen XL at baseline, day 4, day 8, and day 12 of treatment. Both 0.5% diltiazem and 0.125% verapamil eye drops significantly reduced IOP compared to control eyes (p < 0.05). Reduction of IOP by 0.5% diltiazem, 0.125% verapamil eye drops were comparable to 0.5% timolol. No surface toxicity or systemic side effects were noted during the study period. Calcium channel blockers, verapamil, and diltia-zem significantly reduced IOP in rabbiteyes. This group of drugs may have a potential role in treatment of glaucoma How to cite this article: Ganekal S, Dorairaj S, Jhanji V, Kudlu K. Effect of Topical Calcium Channel Blockers on Intraocular Pressure in Steroid-induced Glaucoma. J Current Glau Prac 2014;8(1):15-19.

  1. The protective effect of supplemental calcium on colonic permeability depends on a calcium phosphate-induced increase in luminal buffering capacity.

    PubMed

    Schepens, Marloes A A; ten Bruggencate, Sandra J M; Schonewille, Arjan J; Brummer, Robert-Jan M; van der Meer, Roelof; Bovee-Oudenhoven, Ingeborg M J

    2012-04-01

    An increased intestinal permeability is associated with several diseases. Previously, we have shown that dietary Ca decreases colonic permeability in rats. This might be explained by a calcium-phosphate-induced increase in luminal buffering capacity, which protects against an acidic pH due to microbial fermentation. Therefore, we investigated whether dietary phosphate is a co-player in the effect of Ca on permeability. Rats were fed a humanised low-Ca diet, or a similar diet supplemented with Ca and containing either high, medium or low phosphate concentrations. Chromium-EDTA was added as an inert dietary intestinal permeability marker. After dietary adaptation, short-chain fructo-oligosaccharides (scFOS) were added to all diets to stimulate fermentation, acidify the colonic contents and induce an increase in permeability. Dietary Ca prevented the scFOS-induced increase in intestinal permeability in rats fed medium- and high-phosphate diets but not in those fed the low-phosphate diet. This was associated with higher faecal water cytotoxicity and higher caecal lactate levels in the latter group. Moreover, food intake and body weight during scFOS supplementation were adversely affected by the low-phosphate diet. Importantly, luminal buffering capacity was higher in rats fed the medium- and high-phosphate diets compared with those fed the low-phosphate diet. The protective effect of dietary Ca on intestinal permeability is impaired if dietary phosphate is low. This is associated with a calcium phosphate-induced increase in luminal buffering capacity. Dragging phosphate into the colon and thereby increasing the colonic phosphate concentration is at least part of the mechanism behind the protective effect of Ca on intestinal permeability.

  2. The Sleep-inducing Lipid Oleamide Deconvolutes Gap Junction Communication and Calcium Wave Transmission in Glial Cells

    PubMed Central

    Guan, Xiaojun; Cravatt, Benjamin F.; Ehring, George R.; Hall, James E.; Boger, Dale L.; Lerner, Richard A.; Gilula, Norton B.

    1997-01-01

    Oleamide is a sleep-inducing lipid originally isolated from the cerebrospinal fluid of sleep-deprived cats. Oleamide was found to potently and selectively inactivate gap junction–mediated communication between rat glial cells. In contrast, oleamide had no effect on mechanically stimulated calcium wave transmission in this same cell type. Other chemical compounds traditionally used as inhibitors of gap junctional communication, like heptanol and 18β-glycyrrhetinic acid, blocked not only gap junctional communication but also intercellular calcium signaling. Given the central role for intercellular small molecule and electrical signaling in central nervous system function, oleamide- induced inactivation of glial cell gap junction channels may serve to regulate communication between brain cells, and in doing so, may influence higher order neuronal events like sleep induction. PMID:9412472

  3. Calcium waves.

    PubMed

    Jaffe, Lionel F

    2008-04-12

    Waves through living systems are best characterized by their speeds at 20 degrees C. These speeds vary from those of calcium action potentials to those of ultraslow ones which move at 1-10 and/or 10-20 nm s(-1). All such waves are known or inferred to be calcium waves. The two classes of calcium waves which include ones with important morphogenetic effects are slow waves that move at 0.2-2 microm s(-1) and ultraslow ones. Both may be propagated by cycles in which the entry of calcium through the plasma membrane induces subsurface contraction. This contraction opens nearby stretch-sensitive calcium channels. Calcium entry through these channels propagates the calcium wave. Many slow waves are seen as waves of indentation. Some are considered to act via cellular peristalsis; for example, those which seem to drive the germ plasm to the vegetal pole of the Xenopus egg. Other good examples of morphogenetic slow waves are ones through fertilizing maize eggs, through developing barnacle eggs and through axolotl embryos during neural induction. Good examples of ultraslow morphogenetic waves are ones during inversion in developing Volvox embryos and across developing Drosophila eye discs. Morphogenetic waves may be best pursued by imaging their calcium with aequorins.

  4. 6-OHDA induced calcium influx through N-type calcium channel alters membrane properties via PKA pathway in substantia nigra pars compacta dopaminergic neurons.

    PubMed

    Qu, Liang; Wang, Yuan; Zhang, Hai-Tao; Li, Nan; Wang, Qiang; Yang, Qian; Gao, Guo-Dong; Wang, Xue-Lian

    2014-07-11

    Voltage gated calcium channels (VGCC) are sensitive to oxidative stress, and their activation or inactivation can impact cell death. Although these channels have been extensively studied in expression systems, their role in the brain, particularly in the substantia nigra pars compacta (SNc), remain controversial. In this study, we assessed 6-hydroxydopamine (6-OHDA) induced transformation of firing pattern and functional changes of calcium channels in SNc dopaminergic neurons. Application of 6-OHDA (0.5-2mM) evoked a dose-dependent, desensitizing inward current and intracellular free calcium concentration ([Ca(2+)]i) rise. In voltage clamp, ω-conotoxin-sensitive Ca(2+) current modulation mediated by 6-OHDA reflected an altered sensitivity. Furthermore, we found that 6-OHDA modulated Ca(2+) currents through PKA pathway. These results provided evidence for the potential role of VGCCs and PKA involved in oxidative stress in degeneration of SNc neurons in Parkinson's disease (PD). Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  5. Comparison of Clinical Factors Between Patients With Angiotensin-Converting Enzyme Inhibitor-Induced Angioedema and Cough.

    PubMed

    Hallberg, Pär; Nagy, Julia; Karawajczyk, Malgorzata; Nordang, Leif; Islander, Gunilla; Norling, Pia; Johansson, Hans-Erik; Kämpe, Mary; Hugosson, Svante; Yue, Qun-Ying; Wadelius, Mia

    2017-04-01

    Angioedema is a rare and serious adverse drug reaction (ADR) to angiotensin-converting enzyme (ACE) inhibitor treatment. Dry cough is a common side effect of ACE inhibitors and has been identified as a possible risk factor for angioedema. We compared characteristics between patients with ACE inhibitor-induced angioedema and cough with the aim of identifying risk factors that differ between these adverse events. Data on patients with angioedema or cough induced by ACE inhibitors were collected from the Swedish database of spontaneously reported ADRs or from collaborating clinicians. Wilcoxon rank sum test, Fisher's exact test, and odds ratios (ORs) with 95% CIs were used to test for between-group differences. The significance threshold was set to P <0.00128 to correct for multiple comparisons. Clinical characteristics were compared between 168 patients with angioedema and 121 with cough only. Smoking and concomitant selective calcium channel blocker treatment were more frequent among patients with angioedema than cough: OR = 4.3, 95% CI = 2.1-8.9, P = 2.2 × 10 -5 , and OR = 3.7, 95% CI = 2.0-7.0, P = 1.7 × 10 -5 . Angioedema cases were seen more often in male patients (OR = 2.2, 95% CI = 1.4-3.6, P = 1.3 × 10 -4 ) and had longer time to onset and higher doses than those with cough ( P = 3.2 × 10 -10 and P = 2.6 × 10 -4 ). A multiple model containing the variables smoking, concurrent calcium channel blocker treatment, male sex, and time to onset accounted for 26% of the variance between the groups. Smoking, comedication with selective calcium channel blockers, male sex, and longer treatment time were associated with ACE inhibitor-induced angioedema rather than cough.

  6. Calcium-containing scaffolds induce bone regeneration by regulating mesenchymal stem cell differentiation and migration.

    PubMed

    Aquino-Martínez, Rubén; Angelo, Alcira P; Pujol, Francesc Ventura

    2017-11-16

    Osteoinduction and subsequent bone formation rely on efficient mesenchymal stem cell (MSC) recruitment. It is also known that migration is induced by gradients of growth factors and cytokines. Degradation of Ca 2+ -containing biomaterials mimics the bone remodeling compartment producing a localized calcium-rich osteoinductive microenvironment. The aim of our study was to determine the effect of calcium sulfate (CaSO 4 ) on MSC migration. In addition, to evaluate the influence of CaSO 4 on MSC differentiation and the potential molecular mechanisms involved. A circular calvarial bone defect (5 mm diameter) was created in the parietal bone of 35 Balb-C mice. We prepared and implanted a cell-free agarose/gelatin scaffold alone or in combination with different CaSO 4 concentrations into the bone defects. After 7 weeks, we determined the new bone regenerated by micro-CT and histological analysis. In vitro, we evaluated the CaSO 4 effects on MSC migration by both wound healing and agarose spot assays. Osteoblastic gene expression after BMP-2 and CaSO 4 treatment was also evaluated by qPCR. CaSO 4 increased MSC migration and bone formation in a concentration-dependent manner. Micro-CT analysis showed that the addition of CaSO 4 significantly enhanced bone regeneration compared to the scaffold alone. The histological evaluation confirmed an increased number of endogenous cells recruited into the cell-free CaSO 4 -containing scaffolds. Furthermore, MSC migration in vitro and active AKT levels were attenuated when CaSO 4 and BMP-2 were in combination. Addition of LY294002 and Wortmannin abrogated the CaSO 4 effects on MSC migration. Specific CaSO 4 concentrations induce bone regeneration of calvarial defects in part by acting on the host's undifferentiated MSCs and promoting their migration. Progenitor cell recruitment is followed by a gradual increment in osteoblast gene expression. Moreover, CaSO 4 regulates BMP-2-induced MSC migration by differentially activating the PI3

  7. Analysis and prediction of calcium-binding pockets from apo-protein structures exhibiting calcium-induced localized conformational changes

    PubMed Central

    Wang, Xue; Zhao, Kun; Kirberger, Michael; Wong, Hing; Chen, Guantao; Yang, Jenny J

    2010-01-01

    Calcium binding in proteins exhibits a wide range of polygonal geometries that relate directly to an equally diverse set of biological functions. The binding process stabilizes protein structures and typically results in local conformational change and/or global restructuring of the backbone. Previously, we established the MUG program, which utilized multiple geometries in the Ca2+-binding pockets of holoproteins to identify such pockets, ignoring possible Ca2+-induced conformational change. In this article, we first report our progress in the analysis of Ca2+-induced conformational changes followed by improved prediction of Ca2+-binding sites in the large group of Ca2+-binding proteins that exhibit only localized conformational changes. The MUGSR algorithm was devised to incorporate side chain torsional rotation as a predictor. The output from MUGSR presents groups of residues where each group, typically containing two to five residues, is a potential binding pocket. MUGSR was applied to both X-ray apo structures and NMR holo structures, which did not use calcium distance constraints in structure calculations. Predicted pockets were validated by comparison with homologous holo structures. Defining a “correct hit” as a group of residues containing at least two true ligand residues, the sensitivity was at least 90%; whereas for a “correct hit” defined as a group of residues containing at least three true ligand residues, the sensitivity was at least 78%. These data suggest that Ca2+-binding pockets are at least partially prepositioned to chelate the ion in the apo form of the protein. PMID:20512971

  8. Predictive factor and antihypertensive usage of tyrosine kinase inhibitor-induced hypertension in kidney cancer patients

    PubMed Central

    IZUMI, KOUJI; ITAI, SHINGO; TAKAHASHI, YOSHIKO; MAOLAKE, AERKEN; NAMIKI, MIKIO

    2014-01-01

    Hypertension (HT) is the common adverse event associated with vascular endothelial growth factor receptor-tyrosine kinase inhibitors (VEGFR-TKI). The present study was performed to identify the predictive factors of TKI-induced HT and to determine the classes of antihypertensive agents (AHTA) that demonstrate optimal efficacy against this type of HT. The charts of 50 cases of patients that had received VEGFR-TKI treatment were retrospectively examined. The association between patient background and TKI-induced HT, and the effect of administering AHTA were analyzed. High systolic blood pressure at baseline was identified to be a predictive factor for HT. In addition, there was no difference observed between calcium channel blockers (CCBs) and angiotensin receptor II blockers (ARBs) as first-line AHTA for the control of HT. The findings of the present study may aid with predicting the onset of TKI-induced HT, as well as for its management via the primary use of either CCBs or ARBs. PMID:24959266

  9. Spine Calcium Transients Induced by Synaptically-Evoked Action Potentials Can Predict Synapse Location and Establish Synaptic Democracy

    PubMed Central

    Meredith, Rhiannon M.; van Ooyen, Arjen

    2012-01-01

    CA1 pyramidal neurons receive hundreds of synaptic inputs at different distances from the soma. Distance-dependent synaptic scaling enables distal and proximal synapses to influence the somatic membrane equally, a phenomenon called “synaptic democracy”. How this is established is unclear. The backpropagating action potential (BAP) is hypothesised to provide distance-dependent information to synapses, allowing synaptic strengths to scale accordingly. Experimental measurements show that a BAP evoked by current injection at the soma causes calcium currents in the apical shaft whose amplitudes decay with distance from the soma. However, in vivo action potentials are not induced by somatic current injection but by synaptic inputs along the dendrites, which creates a different excitable state of the dendrites. Due to technical limitations, it is not possible to study experimentally whether distance information can also be provided by synaptically-evoked BAPs. Therefore we adapted a realistic morphological and electrophysiological model to measure BAP-induced voltage and calcium signals in spines after Schaffer collateral synapse stimulation. We show that peak calcium concentration is highly correlated with soma-synapse distance under a number of physiologically-realistic suprathreshold stimulation regimes and for a range of dendritic morphologies. Peak calcium levels also predicted the attenuation of the EPSP across the dendritic tree. Furthermore, we show that peak calcium can be used to set up a synaptic democracy in a homeostatic manner, whereby synapses regulate their synaptic strength on the basis of the difference between peak calcium and a uniform target value. We conclude that information derived from synaptically-generated BAPs can indicate synapse location and can subsequently be utilised to implement a synaptic democracy. PMID:22719238

  10. Mitochondrial impairment increases FL-PINK1 levels by calcium-dependent gene expression☆

    PubMed Central

    Gómez-Sánchez, Rubén; Gegg, Matthew E.; Bravo-San Pedro, José M.; Niso-Santano, Mireia; Alvarez-Erviti, Lydia; Pizarro-Estrella, Elisa; Gutiérrez-Martín, Yolanda; Alvarez-Barrientos, Alberto; Fuentes, José M.; González-Polo, Rosa Ana; Schapira, Anthony H.V.

    2014-01-01

    Mutations of the PTEN-induced kinase 1 (PINK1) gene are a cause of autosomal recessive Parkinson's disease (PD). This gene encodes a mitochondrial serine/threonine kinase, which is partly localized to mitochondria, and has been shown to play a role in protecting neuronal cells from oxidative stress and cell death, perhaps related to its role in mitochondrial dynamics and mitophagy. In this study, we report that increased mitochondrial PINK1 levels observed in human neuroblastoma SH-SY5Y cells after carbonyl cyanide m-chlorophelyhydrazone (CCCP) treatment were due to de novo protein synthesis, and not just increased stabilization of full length PINK1 (FL-PINK1). PINK1 mRNA levels were significantly increased by 4-fold after 24 h. FL-PINK1 protein levels at this time point were significantly higher than vehicle-treated, or cells treated with CCCP for 3 h, despite mitochondrial content being decreased by 29%. We have also shown that CCCP dissipated the mitochondrial membrane potential (Δψm) and induced entry of extracellular calcium through L/N-type calcium channels. The calcium chelating agent BAPTA-AM impaired the CCCP-induced PINK1 mRNA and protein expression. Furthermore, CCCP treatment activated the transcription factor c-Fos in a calcium-dependent manner. These data indicate that PINK1 expression is significantly increased upon CCCP-induced mitophagy in a calcium-dependent manner. This increase in expression continues after peak Parkin mitochondrial translocation, suggesting a role for PINK1 in mitophagy that is downstream of ubiquitination of mitochondrial substrates. This sensitivity to intracellular calcium levels supports the hypothesis that PINK1 may also play a role in cellular calcium homeostasis and neuroprotection. PMID:24184327

  11. Detection of light-induced changes of intracellular ionized calcium concentration in Limulus ventral photoreceptors using arsenazo III

    PubMed Central

    Brown, J. E.; Brown, P. K.; Pinto, L. H.

    1977-01-01

    1. The metallochromic indicator dye, arsenazo III, was injected intracellularly into Limulus ventral photoreceptor cells to concentrations greater than 1 mM. 2. The absorption spectrum (450-750 nm) of the dye in single dark-adapted cells was measured by a scanning microspectrophotometer. When a cell was light-adapted, the absorption of the dye changed; the difference spectrum had two maxima at about 610 and 660 nm, a broad minimum at about 540 nm and an isosbestic point at about 585 nm. 3. When intracellular calcium concentration was raised in dark-adapted cells previously injected with arsenazo III, the difference spectum had two maxima at about 610 and 660 nm, a broad minimum at about 530 nm and an isosbestic point at about 585 nm. The injection of Mg2+ into dark-adapted cells previously injected with the dye induced a difference spectrum that had a single maximum at about 620 nm. Also, decreasing the intracellular pH of cells previously injected with the dye induced a difference spectrum that had a minimum at about 620 nm. The evidence suggests that there is a rise of intracellular ionized calcium when a Limulus ventral photoreceptor is light-adapted. 4. The intracellular calcium concentration, [Ca2+]1, in light-adapted photoreceptors was estimated to reach at least 10-4 M by compaing the light-induced difference spectra measured in ventral photoreceptors with a standard curve determined in microcuvettes containing 2mM arsenazo III in 400 mM-KCl, 1 mM-MgCl2 and 25 mM MOPS at pH 7·0. 5. In cells injected to less than 3 mM arsenazo III, light induced a transient decrease in optical transmission at 660 nm (T660). This decrease in T660 indicates that illumination of a ventral photoreceptor normally causes a transient increase of [Ca2+]1. 6. Arsenazo III was found to be sensitive, selective and rapid enough to measure light-induced changes of intracellular ionized calcium in Limulus ventral photoreceptor cells. PMID:17732

  12. Factors to consider in the selection of a calcium supplement.

    PubMed Central

    Shangraw, R F

    1989-01-01

    Calcium supplements are widely used, yet many questions remain as to the absorption of various calcium salts. Because the solubility of many calcium salts is dependent upon pH, the type of salt used, the condition of the patient, and the time of administration should be considered. Studies show that many calcium supplements on the market today do not meet standards of quality established in the "U.S. Pharmacopeia" (USP). Consumers must be discerning about the products they purchase. Calcium supplements should be taken with meals to ensure solubility. Calcium carbonate, and particularly tribasic calcium phosphate tablets, are not recommended for patients with achlorhydria. Calcium tablets, like almost all drugs, should be taken with 8 ounces of water or other liquid. PMID:2517700

  13. Biotic and abiotic effects on CO2 sequestration during microbially-induced calcium carbonate precipitation.

    PubMed

    Okyay, Tugba Onal; Rodrigues, Debora F

    2015-03-01

    In this study, CO2 sequestration was investigated through the microbially-induced calcium carbonate precipitation (MICP) process with isolates obtained from a cave called 'Cave Without A Name' (Boerne, TX, USA) and the Pamukkale travertines (Denizli, Turkey). The majority of the bacterial isolates obtained from these habitats belonged to the genera Sporosarcina, Brevundimonas, Sphingobacterium and Acinetobacter. The isolates were investigated for their capability to precipitate calcium carbonate and sequester CO2. Biotic and abiotic effects of CO2 sequestration during MICP were also investigated. In the biotic effect, we observed that the rate and concentration of CO2 sequestered was dependent on the species or strains. The main abiotic factors affecting CO2 sequestration during MICP were the pH and medium components. The increase in pH led to enhanced CO2 sequestration by the growth medium. The growth medium components, on the other hand, were shown to affect both the urease activity and CO2 sequestration. Through the Plackett-Burman experimental design, the most important growth medium component involved in CO2 sequestration was determined to be urea. The optimized medium composition by the Plackett-Burman design for each isolate led to a statistically significant increase, of up to 148.9%, in CO2 uptake through calcification mechanisms. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. Inhibition of Sphingosine Kinase 1 Ameliorates Angiotensin II-Induced Hypertension and Inhibits Transmembrane Calcium Entry via Store-Operated Calcium Channel

    PubMed Central

    Wilson, Parker C.; Fitzgibbon, Wayne R.; Garrett, Sara M.; Jaffa, Ayad A.; Luttrell, Louis M.; Brands, Michael W.

    2015-01-01

    Angiotensin II (AngII) plays a critical role in the regulation of vascular tone and blood pressure mainly via regulation of Ca2+ mobilization. Several reports have implicated sphingosine kinase 1 (SK1)/sphingosine 1-phosphate (S1P) in the mobilization of intracellular Ca2+ through a yet-undefined mechanism. Here we demonstrate that AngII-induces biphasic calcium entry in vascular smooth muscle cells, consisting of an immediate peak due to inositol tris-phosphate-dependent release of intracellular calcium, followed by a sustained transmembrane Ca2+ influx through store-operated calcium channels (SOCs). Inhibition of SK1 attenuates the second phase of transmembrane Ca2+ influx, suggesting a role for SK1 in AngII-dependent activation of SOC. Intracellular S1P triggers SOC-dependent Ca2+ influx independent of S1P receptors, whereas external application of S1P stimulated S1P receptor-dependent Ca2+ influx that is insensitive to inhibitors of SOCs, suggesting that the SK1/S1P axis regulates store-operated calcium entry via intracellular rather than extracellular actions. Genetic deletion of SK1 significantly inhibits both the acute hypertensive response to AngII in anaesthetized SK1 knockout mice and the sustained hypertensive response to continuous infusion of AngII in conscious animals. Collectively these data implicate SK1 as the missing link that connects the angiotensin AT1A receptor to transmembrane Ca2+ influx and identify SOCs as a potential intracellular target for SK1. PMID:25871850

  15. Calcium plays a key role in paraoxon-induced apoptosis in EL4 cells by regulating both endoplasmic reticulum- and mitochondria-associated pathways.

    PubMed

    Li, Lan; Du, Yi; Ju, Furong; Ma, Shunxiang; Zhang, Shengxiang

    2016-01-01

    Paraoxon (POX) is one of the most toxic organophosphorus pesticides, but its toxic mechanisms associated with apoptosis remain unclear. The aim of this study was to investigate calcium-associated mechanisms in POX-induced apoptosis in EL4 cells. EL4 cells were exposed to POX for 0-16 h. EGTA was used to chelate Ca(2+ ) in extracellular medium, and heparin and procaine were used to inhibit Ca(2+ )efflux from the endoplasmic reticulum (ER). Z-ATAD-FMK was used to inhibit caspase-12 activity. The apoptotic rate assay, western blotting and immunocytochemistry (ICC) were used to reveal the mechanisms of POX-induced apoptosis. POX significantly increased the expression and activation of caspase-12 and caspase-3, enhanced expression of calpain 1 and calpain 2, and induced the release of cyt c, but did not change the expression of Grp 78. Inhibiting caspase-12 activity alleviated POX-induced upregulation of calpain 1 and caspase-3, promoted POX-induced upregulation of calpain 2, and reduced POX-induced cyt c release, suggesting that there was a cross-talk between the ER-associated pathway and mitochondria-associated apoptotic signals. Attenuating intracellular calcium concentration with EGTA, heparin or procaine decreased POX-induced upregulation of calpain 1, calpain 2, caspase-12 and caspase-3, and reduced POX-induced cyt c release. After pretreatment with EGTA or procaine, POX significantly promoted expression of Grp 78. Calcium played a key role in POX-induced apoptosis in EL4 cells by regulating both ER- and mitochondria-associated pathways. The cross-talk of ER- and mitochondria-associated pathways was accomplished through calcium signal.

  16. ATP release due to Thy-1–integrin binding induces P2X7-mediated calcium entry required for focal adhesion formation

    PubMed Central

    Henríquez, Mauricio; Herrera-Molina, Rodrigo; Valdivia, Alejandra; Alvarez, Alvaro; Kong, Milene; Muñoz, Nicolás; Eisner, Verónica; Jaimovich, Enrique; Schneider, Pascal; Quest, Andrew F. G.; Leyton, Lisette

    2011-01-01

    Thy-1, an abundant mammalian glycoprotein, interacts with αvβ3 integrin and syndecan-4 in astrocytes and thus triggers signaling events that involve RhoA and its effector p160ROCK, thereby increasing astrocyte adhesion to the extracellular matrix. The signaling cascade includes calcium-dependent activation of protein kinase Cα upstream of Rho; however, what causes the intracellular calcium transients required to promote adhesion remains unclear. Purinergic P2X7 receptors are important for astrocyte function and form large non-selective cation pores upon binding to their ligand, ATP. Thus, we evaluated whether the intracellular calcium required for Thy-1-induced cell adhesion stems from influx mediated by ATP-activated P2X7 receptors. Results show that adhesion induced by the fusion protein Thy-1-Fc was preceded by both ATP release and sustained intracellular calcium elevation. Elimination of extracellular ATP with Apyrase, chelation of extracellular calcium with EGTA, or inhibition of P2X7 with oxidized ATP, all individually blocked intracellular calcium increase and Thy-1-stimulated adhesion. Moreover, Thy-1 mutated in the integrin-binding site did not trigger ATP release, and silencing of P2X7 with specific siRNA blocked Thy-1-induced adhesion. This study is the first to demonstrate a functional link between αvβ3 integrin and P2X7 receptors, and to reveal an important, hitherto unanticipated, role for P2X7 in calcium-dependent signaling required for Thy-1-stimulated astrocyte adhesion. PMID:21502139

  17. Differential effects of the steaming time and frequency for manufactured red Liriope platyphylla on nerve growth factor secretion ability, nerve growth factor receptor signaling pathway and regulation of calcium concentration.

    PubMed

    Choi, Sun Il; Goo, Jun Seo; Kim, Ji Eun; Nam, So Hee; Hwang, In Sik; Lee, Hye Ryun; Lee, Young Ju; Son, Hong Joo; Lee, Hee Seob; Lee, Jong Sup; Kim, Hak Jin; Hwang, Dae Youn

    2012-11-01

    The herb Liriope platyphylla (LP) has been considered to have curative properties for diabetes, asthma and neurodegenerative disorders. To examine the effects of steaming time and frequency of manufactured red LP (RLP) on the nerve growth factor (NGF) secretion ability and NGF receptor signaling pathway, the NGF concentration, cell differentiation, NGF signaling pathway and calcium concentration were analyzed in neuronal cells treated with several types of LPs manufactured under different conditions. The maximum NGF secretion was observed in B35 cells treated with 50 µg/ml LP extract steamed for 9 h (9-SLP) and with two repeated steps (3 h steaming and 24 h air-dried) carried out 7 times (7-SALP). No significant changes in viability were detected in any of the cells treated with the various LPs, with the exception of 0-SLP and 0-SALP. In addition, PC12 cell differentiation was induced by treatment with the NGF-containing conditional medium (CM) collected from the RLP-treated cells. The levels of TrkA and extracellular signal-regulated kinase (ERK) phosphorylation in the high affinity NGF receptor signaling pathway were significantly higher in the cells treated with 3-SLP or 1-SALP/3-SALP CM compared with those treated with the vehicle CM. In the low affinity NGF receptor pathway, the expression levels of most components were higher in the 9-, 15- and 24-SALP CM-treated cells compared with the vehicle CM-treated cells. However, this level was significantly altered in cells treated with 3-SALP CM. Furthermore, an examination of the RLP function on calcium regulation revealed that only the LP- or RLP-treated cells exhibited changes in intracellular and extracellular calcium levels. RLP induced a significant decrease in the intracellular calcium levels and an increase in the extracellular calcium levels. These results suggest the possibility that steaming-processed LP may aid in the relief of neurodegenerative diseases through the NGF secretion ability and NGF

  18. Mechanisms of Pyrethroid Insecticide-Induced Stimulation of Calcium Influx in Neocortical Neurons

    PubMed Central

    Cao, Zhengyu; Shafer, Timothy J.

    2011-01-01

    Pyrethroid insecticides bind to voltage-gated sodium channels (VGSCs) and modify their gating kinetics, thereby disrupting neuronal function. Pyrethroids have also been reported to alter the function of other channel types, including activation of voltage-gated calcium channels. Therefore, the present study compared the ability of 11 structurally diverse pyrethroids to evoke Ca2+ influx in primary cultures of mouse neocortical neurons. Nine pyrethroids (tefluthrin, deltamethrin, λ-cyhalothrin, β-cyfluthrin, esfenvalerate, S-bioallethrin, fenpropathrin, cypermethrin, and bifenthrin) produced concentration-dependent elevations in intracellular calcium concentration ([Ca2+]i) in neocortical neurons. Permethrin and resmethrin were without effect on [Ca2+]i. These pyrethroids displayed a range of efficacies on Ca2+ influx; however, the EC50 values for active pyrethroids all were within one order of magnitude. Tetrodotoxin blocked increases in [Ca2+]i caused by all nine active pyrethroids, indicating that the effects depended on VGSC activation. The pathways for deltamethrin- and tefluthrin-induced Ca2+ influx include N-methyl-d-aspartic acid receptors, L-type Ca2+ channels, and reverse mode of operation of the Na+/Ca2+ exchanger inasmuch as antagonists of these sites blocked deltamethrin-induced Ca2+ influx. These data demonstrate that pyrethroids stimulate Ca2+ entry into neurons subsequent to their actions on VGSCs. PMID:20881019

  19. Voltage-gated calcium flux mediates Escherichia coli mechanosensation.

    PubMed

    Bruni, Giancarlo N; Weekley, R Andrew; Dodd, Benjamin J T; Kralj, Joel M

    2017-08-29

    Electrically excitable cells harness voltage-coupled calcium influx to transmit intracellular signals, typically studied in neurons and cardiomyocytes. Despite intense study in higher organisms, investigations of voltage and calcium signaling in bacteria have lagged due to their small size and a lack of sensitive tools. Only recently were bacteria shown to modulate their membrane potential on the timescale of seconds, and little is known about the downstream effects from this modulation. In this paper, we report on the effects of electrophysiology in individual bacteria. A genetically encoded calcium sensor expressed in Escherichia coli revealed calcium transients in single cells. A fusion sensor that simultaneously reports voltage and calcium indicated that calcium influx is induced by voltage depolarizations, similar to metazoan action potentials. Cytoplasmic calcium levels and transients increased upon mechanical stimulation with a hydrogel, and single cells altered protein concentrations dependent on the mechanical environment. Blocking voltage and calcium flux altered mechanically induced changes in protein concentration, while inducing calcium flux reproduced these changes. Thus, voltage and calcium relay a bacterial sense of touch and alter cellular lifestyle. Although the calcium effectors remain unknown, these data open a host of new questions about E. coli , including the identity of the underlying molecular players, as well as other signals conveyed by voltage and calcium. These data also provide evidence that dynamic voltage and calcium exists as a signaling modality in the oldest domain of life, and therefore studying electrophysiology beyond canonical electrically excitable cells could yield exciting new findings.

  20. Voltage-gated calcium flux mediates Escherichia coli mechanosensation

    PubMed Central

    Weekley, R. Andrew; Dodd, Benjamin J. T.

    2017-01-01

    Electrically excitable cells harness voltage-coupled calcium influx to transmit intracellular signals, typically studied in neurons and cardiomyocytes. Despite intense study in higher organisms, investigations of voltage and calcium signaling in bacteria have lagged due to their small size and a lack of sensitive tools. Only recently were bacteria shown to modulate their membrane potential on the timescale of seconds, and little is known about the downstream effects from this modulation. In this paper, we report on the effects of electrophysiology in individual bacteria. A genetically encoded calcium sensor expressed in Escherichia coli revealed calcium transients in single cells. A fusion sensor that simultaneously reports voltage and calcium indicated that calcium influx is induced by voltage depolarizations, similar to metazoan action potentials. Cytoplasmic calcium levels and transients increased upon mechanical stimulation with a hydrogel, and single cells altered protein concentrations dependent on the mechanical environment. Blocking voltage and calcium flux altered mechanically induced changes in protein concentration, while inducing calcium flux reproduced these changes. Thus, voltage and calcium relay a bacterial sense of touch and alter cellular lifestyle. Although the calcium effectors remain unknown, these data open a host of new questions about E. coli, including the identity of the underlying molecular players, as well as other signals conveyed by voltage and calcium. These data also provide evidence that dynamic voltage and calcium exists as a signaling modality in the oldest domain of life, and therefore studying electrophysiology beyond canonical electrically excitable cells could yield exciting new findings. PMID:28808010

  1. Transglutaminase-induced crosslinking of gelatin-calcium carbonate composite films.

    PubMed

    Wang, Yuemeng; Liu, Anjun; Ye, Ran; Wang, Wenhang; Li, Xin

    2015-01-01

    The effects of transglutaminase (TGase) on the rheological profiles and interactions of gelatin-calcium carbonate solutions were studied. In addition, mechanical properties, water vapour permeability and microstructures of gelatin-calcium carbonate films were also investigated and compared. Fluorescence data suggested that the interaction of TGase and gelation-calcium carbonate belonged to a static quenching mechanism, and merely one binding site between TGase and gelatin-calcium carbonate was identified. Moreover, differential scanning calorimetry (DSC), the mechanical properties and the water vapour permeability studies revealed that TGase favoured the strong intramolecular polymerisation of the peptides in gelatin. The microstructures of the surfaces and cross sections in gelatin-calcium carbonate films were shown by scanning electron microscope (SEM) micrographs. The results of the fourier transform infrared spectroscopy (FTIR) indicated that TGase caused conformational changes in the proteins films. Therefore, TGase successfully facilitated the formation of gelatin-calcium carbonate composite films. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Lipid effects on neutrophil calcium signaling induced by opsonized particles: platelet activating factor is only part of the story.

    PubMed

    Wanten, Geert; Kusters, Anneke; van Emst-de Vries, Sjenet E; Tool, Anton; Roos, Dirk; Naber, Ton; Willems, Peter

    2004-08-01

    Total parenteral nutrition is frequently used in clinical practice to improve the nutritional status of patients. However, the risk for infectious complications remains a drawback in which immune-modulating effects of the lipid component may play a role. To characterize these lipid effects we investigated neutrophil activation by opsonized yeast particles under influence of lipid emulsions derived from fish oil (VLCT), olive oil (LCT-MUFA), soybean oil (LCT), and a physical mixture of coconut and soybean oil (LCT-MCT). Serum-treated zymosan (STZ) evoked a biphasic increase in cytosolic Ca2+ concentration ([Ca2+]c) with an initial slow rise that turned into a second fast rise until a plateau was reached. LCT-MCT (5 mM) pretreatment markedly increased the rate of [Ca2+]c rise during the initial phase, abolished the second phase and lowered the plateau. These effects of LCT-MCT were mimicked by the protein kinase C (PKC) activating phorbol ester PMA. LCT, LCT-MUFA and VLCT, on the other hand, decreased the rate of [Ca2+]c rise during both phases and lowered the plateau. The platelet-activating factor (PAF) receptor antagonist WEB 2086 inhibited the second phase, demonstrating that PAF acts as an intercellular messenger in STZ-induced Ca2+ mobilization, but did not interfere with the stimulatory effect of LCT-MCT or PMA on the initial rate of [Ca2+]c rise. Structurally different lipids act only in part through PAF to distinctively modulate neutrophil calcium signaling in response to activation by opsonized particles. Copyright 2003 Elsevier Ltd.

  3. Sperm chemotaxis in siphonophores. II. Calcium-dependent asymmetrical movement of spermatozoa induced by the attractant.

    PubMed

    Cosson, M P; Carré, D; Cosson, J

    1984-06-01

    Spermatozoa from siphonophores have been shown to be attracted towards an extracellular structure, the cupule, which covers the predetermined site of fertilization of the egg. Observations on sperm behaviour during the chemotactic response show that spermatozoa describe trajectories of large diameter (700-1000 micron) while far from the cupule, and of smaller diameter (200 micron) in the cupule area. The transition between the two types of swimming occurs progressively when spermatozoa cross a 3 mm wide area around the cupule. After a few minutes 99% of the spermatozoa keep swimming around the attractant source, following circular paths 150-200 micron in diameter. In the absence of the attractant, comparable modifications of sperm trajectories are observed in the presence of the ionophore A23187 and high calcium concentrations. In the presence of 10(-2) M calcium ions, A23187-treated spermatozoa describe trajectories 200 micron in diameter, which increase up to 800 micron at lower calcium concentrations (10(-6) M). In the absence of calcium ions, spermatozoa swim across the cupule area without modification of their trajectories and no sperm accumulation can be detected. This requirement of the chemotactic response for calcium ions is observed either with fresh cupules stuck on the eggs, with cupules separated from the eggs, or with cupule extracts. Moreover, a soluble component fractionated from the cupule induces, when diluted in sea water, a reduction in the size of the sperm trajectories and this also requires calcium ions. The present data show that the chemotactic response of siphonophore sperm, which requires millimolar concentrations of calcium ions, occurs through a non-transient induction of increased asymmetry of the flagellar waveform. It is proposed that the natural attractant operates to produce an increase in the intraaxonemal calcium concentration.

  4. The structural alteration and aggregation propensity of glycated lens crystallins in the presence of calcium: Importance of lens calcium homeostasis in development of diabetic cataracts

    NASA Astrophysics Data System (ADS)

    ZM, Sara Zafaranchi; Khoshaman, Kazem; Masoudi, Raheleh; Hemmateenejad, Bahram; Yousefi, Reza

    2017-01-01

    The imbalance of the calcium homeostasis in the lenticular tissues of diabetic patients is an important risk factor for development of cataract diseases. In the current study, the impact of elevated levels of calcium ions were investigated on structure and aggregation propensity of glycated lens crystallins using gel electrophoresis and spectroscopic assessments. The glycated proteins indicated significant resistance against calcium-induced structural insults and aggregation. While, glycated crystallins revealed an increased conformational stability; a slight instability was observed for these proteins upon interaction with calcium ions. Also, in the presence of calcium, the proteolytic pattern of native crystallins was altered and that of glycated protein counterparts remained almost unchanged. According to results of this study it is suggested that the structural alteration of lens crystallins upon glycation may significantly reduce their calcium buffering capacity in eye lenses. Therefore, under chronic hyperglycemia accumulation of this cataractogenic metal ion in the lenticular tissues may subsequently culminate in activation of different pathogenic pathways, leading to development of lens opacity and cataract diseases.

  5. Calcium Supplements: A Risk Factor for Heart Attack?

    MedlinePlus

    ... increased risk of heart attack, stroke or other cardiovascular diseases from taking calcium supplements for men only. Other ... et al. Calcium supplement intake and risk of cardiovascular disease in women. Osteoporosis International. 2014;25:2047. Waldman ...

  6. Calcium and ZmCCaMK are involved in brassinosteroid-induced antioxidant defense in maize leaves.

    PubMed

    Yan, Jingwei; Guan, Li; Sun, Yue; Zhu, Yuan; Liu, Lei; Lu, Rui; Jiang, Mingyi; Tan, Mingpu; Zhang, Aying

    2015-05-01

    Brassinosteroids (BRs) have been shown to enhance stress tolerance by inducing antioxidant defense systems. However, the mechanisms of BR-induced antioxidant defense in plants remain to be determined. In this study, the role of calcium (Ca(2+)) and maize calcium/calmodulin-dependent protein kinase (CCaMK), ZmCCaMK, in BR-induced antioxidant defense, and the relationship between ZmCCaMK and Ca(2+) in BR signaling were investigated. BR treatment led to a significant increase in cytosolic Ca(2+) concentration in protoplasts from maize mesophyll, and Ca(2+) was shown to be required for BR-induced antioxidant defense. Treatment with BR induced increases in gene expression and enzyme activity of ZmCCaMK in maize leaves. Transient overexpression and silencing of ZmCCaMK in maize protoplasts demonstrated that ZmCCaMK was required for BR-induced antioxidant defense. The requirement for CCaMK was further investigated using a loss-of-function mutant of OsCCaMK, the orthologous gene of ZmCCaMK in rice. Consistent with the findings in maize, BR treatment could not induce antioxidant defense in the rice OsCCAMK mutant. Furthermore, Ca(2+) was required for BR-induced gene expression and activation of ZmCCaMK, while ZmCCaMK was shown to enhance the BR-induced increase in cytosolic Ca(2+) concentration. Moreover, our results also showed that ZmCCaMK and H2O2 influenced each other. These results indicate that Ca(2+) works together with ZmCCaMK in BR-induced antioxidant defense, and there are two positive feedback loops between Ca(2+) or H2O2 and ZmCCaMK in BR signaling in maize. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  7. Stretch induced endothelin-1 secretion by adult rat astrocytes involves calcium influx via stretch-activated ion channels (SACs)

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

    Ostrow, Lyle W., E-mail: lostrow1@jhmi.edu; Suchyna, Thomas M.; Sachs, Frederick

    2011-06-24

    Highlights: {yields} Endothelin-1 expression by adult rat astrocytes correlates with cell proliferation. {yields} Stretch-induced ET-1 is inhibited by GsMtx-4, a specific inhibitor of Ca{sup 2+} permeant SACs. {yields} The less specific SAC inhibitor streptomycin also inhibits ET-1 secretion. {yields} Stretch-induced ET-1 production depends on a calcium influx. {yields} SAC pharmacology may provide a new class of therapeutic agents for CNS pathology. -- Abstract: The expression of endothelins (ETs) and ET-receptors is often upregulated in brain pathology. ET-1, a potent vasoconstrictor, also inhibits the expression of astrocyte glutamate transporters and is mitogenic for astrocytes, glioma cells, neurons, and brain capillary endothelia.more » We have previously shown that mechanical stress stimulates ET-1 production by adult rat astrocytes. We now show in adult astrocytes that ET-1 production is driven by calcium influx through stretch-activated ion channels (SACs) and the ET-1 production correlates with cell proliferation. Mechanical stimulation using biaxial stretch (<20%) of a rubber substrate increased ET-1 secretion, and 4 {mu}M GsMTx-4 (a specific inhibitor of SACs) inhibited secretion by 30%. GsMTx-4 did not alter basal ET-1 levels in the absence of stretch. Decreasing the calcium influx by lowering extracellular calcium also inhibited stretch-induced ET-1 secretion without effecting ET-1 secretion in unstretched controls. Furthermore, inhibiting SACs with the less specific inhibitor streptomycin also inhibited stretch-induced ET-1 secretion. The data can be explained with a simple model in which ET-1 secretion depends on an internal Ca{sup 2+} threshold. This coupling of mechanical stress to the astrocyte endothelin system through SACs has treatment implications, since all pathology deforms the surrounding parenchyma.« less

  8. Spermidine-Induced Improvement of Reconsolidation of Memory Involves Calcium-Dependent Protein Kinase in Rats

    ERIC Educational Resources Information Center

    Girardi, Bruna Amanda; Ribeiro, Daniela Aymone; Signor, Cristiane; Muller, Michele; Gais, Mayara Ana; Mello, Carlos Fernando; Rubin, Maribel Antonello

    2016-01-01

    In this study, we determined whether the calcium-dependent protein kinase (PKC) signaling pathway is involved in the improvement of fear memory reconsolidation induced by the intrahippocampal administration of spermidine in rats. Male Wistar rats were trained in a fear conditioning apparatus using a 0.4-mA footshock as an unconditioned stimulus.…

  9. The homing of bone marrow MSCs to non-osseous sites for ectopic bone formation induced by osteoinductive calcium phosphate

    PubMed Central

    Song, Guodong; Habibovic, Pamela; Bao, Chongyun; Hu, Jing; van Blitterswijk, Clemens A.; Yuan, Huipin; Chen, Wenchuan; Xu, Hockin H.K.

    2013-01-01

    Osteoinductive biomaterials are promising for bone repair. There is no direct proof that bone marrow mesenchymal stem cells (BMSCs) home to non-osseous sites and participate in ectopic bone formation induced by osteoinductive bioceramics. The objective of this study was to use a sex-mismatched beagle dog model to investigate BMSC homing via blood circulation to participate in ectopic bone formation via osteoinductive biomaterial. BMSCs of male dogs were injected into female femoral marrow cavity. The survival and stable chimerism of donor BMSCs in recipients were confirmed with polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH). Biphasic calcium phosphate (BCP) granules were implanted in dorsal muscles of female dogs. Y chromosomes were detected in samples harvested from female dogs which had received male BMSCs. At 4 weeks, cells with Y-chromosomes were distributed in the new bone matrix throughout the BCP granule implant. At 6 weeks, cells with Y chromosomes were present in newly mineralized woven bone. TRAP positive osteoclast-like cells were observed in 4-week implants, and the number of such cells decreased from 4 to 6 weeks. These results show that osteoprogenitors were recruited from bone marrow and homed to ectopic site to serve as a cell source for calcium phosphate-induced bone formation. In conclusion, BMSCs were demonstrated to migrate from bone marrow through blood circulation to non-osseous bioceramic implant site to contribute to ectopic bone formation in a canine model. BCP induced new bone in muscles without growth factor delivery, showing excellent osteoinductivity that could be useful for bone tissue engineering. PMID:23298780

  10. A role for calcium in the regulation of ATP-binding cassette, sub-family C, member 3 (ABCC3) gene expression in a model of epidermal growth factor-mediated breast cancer epithelial-mesenchymal transition.

    PubMed

    Stewart, Teneale A; Azimi, Iman; Thompson, Erik W; Roberts-Thomson, Sarah J; Monteith, Gregory R

    2015-03-13

    Epithelial-mesenchymal transition (EMT), a process implicated in cancer metastasis, is associated with the transcriptional regulation of members of the ATP-binding cassette superfamily of efflux pumps, and drug resistance in breast cancer cells. Epidermal growth factor (EGF)-induced EMT in MDA-MB-468 breast cancer cells is calcium signal dependent. In this study induction of EMT was shown to result in the transcriptional up-regulation of ATP-binding cassette, subfamily C, member 3 (ABCC3), a member of the ABC transporter superfamily, which has a recognized role in multidrug resistance. Buffering of cytosolic free calcium inhibited EGF-mediated ABCC3 increases, indicating a calcium-dependent mode of regulation. Silencing of TRPM7 (an ion channel involved in EMT associated vimentin induction) did not inhibit ABCC3 up-regulation. Silencing of the store operated calcium entry (SOCE) pathway components ORAI1 and STIM1 also did not alter ABCC3 induction by EGF. However, the calcium permeable ion channel transient receptor potential cation channel, subfamily C, member 1 (TRPC1) appears to contribute to the regulation of both basal and EGF-induced ABCC3 mRNA. Improved understanding of the relationship between calcium signaling, EMT and the regulation of genes important in therapeutic resistance may help identify novel therapeutic targets for breast cancer. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Bilirubin induces a calcium-dependent inhibition of multifunctional Ca2+/calmodulin-dependent kinase II activity in vitro.

    PubMed

    Churn, S B; DeLorenzo, R J; Shapiro, S M

    1995-12-01

    Excessive bilirubin levels in newborn infants result in long-term neurologic deficits that remain after bilirubin levels return to normal. Much of the observed neurologic deficits can be attributed to bilirubin-induced, delayed neuronal cell death. Inhibition of calcium/calmodulin-dependent kinase II (CaM kinase II) activity that precedes cell death is observed in conditions such as seizure activity, stroke, and glutamate excitotoxicity. Because neonatal bilirubin exposure results in neuronal loss in developing brain systems, we tested whether bilirubin exposure would induce an immediate inhibition of CaM activity, in vitro. P-81 filtration assay of basal and calcium-stimulated kinase activity was performed under standard kinase assay conditions. Bilirubin and/or albumin was added to the reaction vessels to determine the effect of these agents on kinase activity. Bilirubin exposure resulted in a concentration-dependent inhibition of CaM kinase II activity (IC50 = 16.78 microM). At concentrations above 50 microM, bilirubin exposure resulted in a 71 +/- 8% (mean +/- SD) inhibition of kinase activity (p < 0.001, t test, n = 10). Bilirubin exposure did not result in kinase inhibition if excessive bilirubin was removed by albumin binding before stimulation of kinase activity (106.9 +/- 9.6% control activity, n = 5). However, removal of bilirubin by binding with albumin after calcium addition did not restore kinase activity. (36.1 +/- 3.8% control activity, n = 5). Thus, once inhibition was observed, the activity could not be restored by addition of albumin. The data suggest that bilirubin exposure resulted in a calcium-dependent inhibition of CaM kinase II activity that, once induced, was not reversible by removing bilirubin by the addition of albumin. Because inhibition of CaM kinase II activity has been correlated with delayed neuronal cell death in many neuropathologic conditions, bilirubin-induced inhibition of this enzyme may be a cellular mechanism by which

  12. Changes in calcium and iron levels in the brains of rats during kainate induced epilepsy

    NASA Astrophysics Data System (ADS)

    Ren, Min-Qin; Ong, Wei-Yi; Makjanic, Jagoda; Watt, Frank

    1999-10-01

    Epilepsy is a recurrent disorder of cerebral function characterised by sudden brief attacks of altered consciousness, motor activity or sensory phenomena, and affects approximately 1% of the population. Kainic acid injection induces neuronal degeneration in rats, is associated with glial hypertrophy and proliferation in the CA3-CA4 fields of hippocampal complex, and is a model for temporal lobe epilepsy. In this study we have applied Nuclear Microscopy to the investigation of the elemental changes within the hippocampus and the cortex areas of the rat brain following kainate injection. Analyses of unstained freeze dried tissue sections taken at 1 day and 1, 2, 3 and 4 weeks following injection were carried out using the Nuclear Microscopy facility at the Research Centre for Nuclear Microscopy, National University of Singapore. Quantitative analysis and elemental mapping indicates that there are significant changes in the calcium levels and distributions in the hippocampus as early as 1 day following injection. Preliminary results indicate a rapid increase in cellular calcium. High levels of calcium can activate calcium dependent proteins and phospholipases. Activation of phospholipase A 2 can be harmful to surrounding neurons through free radical damage. In addition to observed increases in calcium, there was evidence of increases in iron levels. This is consistent with measurements in other degenerative brain disorders, and may signal a late surge in free radical production.

  13. Calcium Orthophosphate-Based Bioceramics

    PubMed Central

    Dorozhkin, Sergey V.

    2013-01-01

    Various types of grafts have been traditionally used to restore damaged bones. In the late 1960s, a strong interest was raised in studying ceramics as potential bone grafts due to their biomechanical properties. A bit later, such synthetic biomaterials were called bioceramics. In principle, bioceramics can be prepared from diverse materials but this review is limited to calcium orthophosphate-based formulations only, which possess the specific advantages due to the chemical similarity to mammalian bones and teeth. During the past 40 years, there have been a number of important achievements in this field. Namely, after the initial development of bioceramics that was just tolerated in the physiological environment, an emphasis was shifted towards the formulations able to form direct chemical bonds with the adjacent bones. Afterwards, by the structural and compositional controls, it became possible to choose whether the calcium orthophosphate-based implants remain biologically stable once incorporated into the skeletal structure or whether they were resorbed over time. At the turn of the millennium, a new concept of regenerative bioceramics was developed and such formulations became an integrated part of the tissue engineering approach. Now calcium orthophosphate scaffolds are designed to induce bone formation and vascularization. These scaffolds are often porous and harbor different biomolecules and/or cells. Therefore, current biomedical applications of calcium orthophosphate bioceramics include bone augmentations, artificial bone grafts, maxillofacial reconstruction, spinal fusion, periodontal disease repairs and bone fillers after tumor surgery. Perspective future applications comprise drug delivery and tissue engineering purposes because calcium orthophosphates appear to be promising carriers of growth factors, bioactive peptides and various types of cells. PMID:28788309

  14. Piperine, a component of black pepper, decreases eugenol-induced cAMP and calcium levels in non-chemosensory 3T3-L1 cells.

    PubMed

    Yoon, Yeo Cho; Kim, Sung-Hee; Kim, Min Jung; Yang, Hye Jeong; Rhyu, Mee-Ra; Park, Jae-Ho

    2015-01-01

    This study investigated the effects of an ethanol extract of black pepper and its constituent, piperine, on odorant-induced signal transduction in non-chemosensory cells. An ethanol extract of black pepper decreased eugenol-induced cAMP and calcium levels in preadipocyte 3T3-L1 cells with no toxicity. Phosphorylation of CREB (cAMP response element-binding protein) was down-regulated by the black pepper extract. The concentration (133.8 mg/g) and retention time (5.5 min) of piperine in the ethanol extract were quantified using UPLC-MS/MS. Pretreatment with piperine decreased eugenol-induced cAMP and calcium levels in 3T3-L1 cells. Piperine also decreased the phosphorylation of CREB, which is up-regulated by eugenol. These results suggest that piperine inhibits the eugenol-induced signal transduction pathway through modulation of cAMP and calcium levels and phosphorylation of CREB in non-chemosensory cells.

  15. Bisphenol A stimulates human prostate cancer cell migration via remodelling of calcium signalling.

    PubMed

    Derouiche, Sandra; Warnier, Marine; Mariot, Pascal; Gosset, Pierre; Mauroy, Brigitte; Bonnal, Jean-Louis; Slomianny, Christian; Delcourt, Philippe; Prevarskaya, Natalia; Roudbaraki, Morad

    2013-12-01

    Bisphenol A (BPA), the principal constituent of reusable water bottles, metal cans, and plastic food containers, has been shown to be involved in human prostate cancer (PCa) cell proliferation. The aim of the present study was to explore the effect of BPA on PCa cell migration and the pathways involved in these processes. Using the transwell technique, we clearly show for the first time that the pre-treatment of the cells with BPA (1-10 nM) induces human PCa cell migration. Using a calcium imaging technique, we show that BPA pre-treatment induces an amplification of Store-Operated Calcium Entry (SOCE) in LNCaP cells. RT-PCR and Western blot experiments allowed the identification of the ion channel proteins which are up-regulated by BPA pre-treatments. These include the Orai1 protein, which is known as an important SOCE actor in various cell systems, including human PCa cells. Using a siRNA strategy, we observed that BPA-induced amplification of SOCE was Orai1-dependent. Interestingly, the BPA-induced PCa cell migration was suppressed when the calcium entry was impaired by the use of SOCE inhibitors (SKF96365, BTP2), or when the extracellular calcium was chelated. Taken together, the results presented here show that BPA induces PCa cells migration via a modulation of the ion channel protein expression involved in calcium entry and in cancer cell migration. The present data provide novel insights into the molecular mechanisms involved in the effects of an environmental factor on cancer cells and suggest both the necessity of preventive measures and the possibility of targeting ion channels in the treatment of PCa cell metastasis.

  16. Live Imaging of Calcium Dynamics during Axon Degeneration Reveals Two Functionally Distinct Phases of Calcium Influx

    PubMed Central

    Yamagishi, Yuya; Tessier-Lavigne, Marc

    2015-01-01

    Calcium is a key regulator of axon degeneration caused by trauma and disease, but its specific spatial and temporal dynamics in injured axons remain unclear. To clarify the function of calcium in axon degeneration, we observed calcium dynamics in single injured neurons in live zebrafish larvae and tested the temporal requirement for calcium in zebrafish neurons and cultured mouse DRG neurons. Using laser axotomy to induce Wallerian degeneration (WD) in zebrafish peripheral sensory axons, we monitored calcium dynamics from injury to fragmentation, revealing two stereotyped phases of axonal calcium influx. First, axotomy triggered a transient local calcium wave originating at the injury site. This initial calcium wave only disrupted mitochondria near the injury site and was not altered by expression of the protective WD slow (WldS) protein. Inducing multiple waves with additional axotomies did not change the kinetics of degeneration. In contrast, a second phase of calcium influx occurring minutes before fragmentation spread as a wave throughout the axon, entered mitochondria, and was abolished by WldS expression. In live zebrafish, chelating calcium after the first wave, but before the second wave, delayed the progress of fragmentation. In cultured DRG neurons, chelating calcium early in the process of WD did not alter degeneration, but chelating calcium late in WD delayed fragmentation. We propose that a terminal calcium wave is a key instructive component of the axon degeneration program. SIGNIFICANCE STATEMENT Axon degeneration resulting from trauma or neurodegenerative disease can cause devastating deficits in neural function. Understanding the molecular and cellular events that execute axon degeneration is essential for developing treatments to address these conditions. Calcium is known to contribute to axon degeneration, but its temporal requirements in this process have been unclear. Live calcium imaging in severed zebrafish neurons and temporally controlled

  17. The influence of phosphate, calcium and magnesium on matrix Gla-protein and vascular calcification: a systematic review.

    PubMed

    Houben, E; Neradova, A; Schurgers, L J; Vervloet, Marc

    2016-01-01

    Vitamin K-dependent matrix Gla protein (MGP) is a key inhibitor of vascular calcification (VC). MGP is synthesized by chondrocytes and vascular smooth muscle cells (VSMC) and the absence or inactivity of MGP results in excessive calcification of both growth plate and vasculature. Apart from its vitamin K dependency little is known about other factors that influence MGP metabolism. Phosphate, calcium and magnesium are involved in bone mineralization and play an important role in VC. In this review we provide a summary of the effect of phosphate, calcium, and magnesium on MGP metabolism. Elevated phosphate and calcium levels promote VC, in part by increasing the release of matrix vesicles (MV) that under the influence of calcium and phosphate become calcification competent. Phosphate and calcium simultaneously induce an upregulation of MGP protein and gene expression, which possibly inhibits calcification. Elevated phosphate levels did not change MGP protein levels in MV. On the contrary, elevated calcium concentrations caused a decrease of MGPloading in MV, which might in part explainthe calcifying effects of MV. Magnesium is a known inhibitor of VC. However, magnesium has been shown to have an inhibitory effect on MGP synthesis induced through downregulation of the calcium-sensing receptor and hereby causing a decrease in calcium induced MGP upregulation. There might also be stimulatory effect of magnesium on MGP in which the TRPM7 channel is involved. In conclusion there is a clear interaction between MGP and phosphate, calcium and magnesium. The upregulation of MGP by phosphate and calcium might be a cellular response that possibly results in the mitigation of VC.

  18. Atorvastatin Calcium Inhibits PDGF-ββ-Induced Proliferation and Migration of VSMCs Through the G0/G1 Cell Cycle Arrest and Suppression of Activated PDGFRβ-PI3K-Akt Signaling Cascade.

    PubMed

    Chen, Shuang; Dong, Siyuan; Li, Zhao; Guo, Xiaofan; Zhang, Naijin; Yu, Bo; Sun, Yingxian

    2017-01-01

    Abnormal proliferation of vascular smooth muscle cells (VSMCs) is a hallmark of vascular lesions, such as atherosclerosis and restenosis. PDGF-ββ, an isoform of PDGF (platelet-derived growth factor), has been demonstrated to induce proliferation and migration of VSMCs. Atorvastatin calcium, a selective inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, has favorable protective effects on VSMCs. This study examined the effects of atorvastatin calcium on the proliferation and migration of PDGF-ββ-treated VSMCs, as well as its underlying mechanisms. MTT assays, Edu imaging, cell cycle analysis, wound healing assays, transwell migration assays, and western blot analysis were performed. Atorvastatin calcium significantly inhibited cell proliferation, DNA synthesis and cell migration of PDGF-ββ-treated VSMCs. We demonstrated that atorvastatin calcium induced cell cycle arrest in the G0/G1 phase in response to PDGF-ββ stimulation and decreased the expression of G0/G1-specific regulatory proteins, including proliferating cell nuclear antigen (PCNA), CDK2, cyclin D1, cyclin E and CDK4 in PDGF-ββ-treated VSMCs. Moreover, pretreatment with atorvastatin calcium inhibited the PDGF-ββ-treated phosphorylation of PDGFRβ and Akt, whereas atorvastatin calcium did not affect the phosphorylation of PLC-γ1 or (ERK) 1/2. Our data suggested that atorvastatin calcium inhibited abnormal proliferation and migration of VSMCs through G0/G1 cell cycle arrest and suppression of the PDGFRβ-Akt signaling cascade. © 2017 The Author(s). Published by S. Karger AG, Basel.

  19. Calcium-regulated nuclear enzymes: potential mediators of phytochrome-induced changes in nuclear metabolism?

    NASA Technical Reports Server (NTRS)

    Roux, S. J.

    1992-01-01

    Calcium ions have been proposed to serve as important regulatory elements in stimulus-response coupling for phytochrome responses. An important test of this hypothesis will be to identify specific targets of calcium action that are required for some growth or development process induced by the photoactivated form of phytochrome (Pfr). Initial studies have revealed that there are at least two enzymes in pea nuclei that are stimulated by Pfr in a Ca(2+)-dependent fashion, a calmodulin-regulated nucleoside triphosphatase and a calmodulin-independent but Ca(2+)-dependent protein kinase. The nucleoside triphosphatase appears to be associated with the nuclear envelope, while the protein kinase co-purifies with a nuclear fraction highly enriched for chromatin. This short review summarizes the latest findings on these enzymes and relates them to what is known about Pfr-regulated nuclear metabolism.

  20. Effects of calcium dobesilate on the synthesis of endothelium-dependent relaxing factors in rabbit isolated aorta

    PubMed Central

    Ruiz, E; Lorente, R; Tejerina, T

    1997-01-01

    Some cardiovascular disturbances which occur in diabetics are a consequence of alterations in vascular contractility as well as in endothelium-dependent relaxation. Calcium dobesilate (DOBE) is a drug used in diabetic retinopathy and its mechanism of action is not yet understood. The aim of this study was to investigate the effects of DOBE on synthesis and release of endothelium-dependent relaxing factor (EDRF) and endothelium-dependent hyperpolarizing factor (EDHF) in rabbit isolated aorta. Endothelium-dependent relaxation induced by acetylcholine (ACh) (10−8–10−5 M) increased in the presence of DOBE 10−5 M only when vascular endothelium was kept intact. NG-nitro-L-arginine methyl ester (L-NAME; 10−8–10−4 M progressively decreased the enhancing effect of DOBE on endothelium-dependent relaxation whereas it was progressively increased by L-Arg. DOBE 10−5 M increased in a non-significant manner endothelium-dependent relaxation induced by ACh when the arteries were incubated with both L-NAME 10−4 M and indomethacin 10−6 M. DOBE (10−6 M and 10−5 M) was able to scavenge superoxide anion radicals generated by the hypoxanthine/xanthine oxidase reaction. These results provide evidence that DOBE is able to affect the vascular disorders associated with diabetes mellitus since it enhances the synthesis of endothelium-dependent relaxing factors. PMID:9208138

  1. Calcium dobesilate may alleviate diabetes-induced endothelial dysfunction and inflammation

    PubMed Central

    Zhou, Yijun; Yuan, Jiangzi; Qi, Chaojun; Shao, Xinghua; Mou, Shan; Ni, Zhaohui

    2017-01-01

    Diabetic kidney disease (DKD) is a leading cause of end-stage renal disease. However, the pathogenesis of DKD remains unclear, and no effective treatments for the disease are available. Thus, there is an urgent need to elucidate the pathogenic mechanisms of DKD and to develop more effective therapies for this disease. Human umbilical vein endothelial cells (HUVECs) were cultured using different D-glucose concentrations to determine the effect of high glucose (HG) on the cells. Alternatively, HUVECs were incubated with 100 µmol/l calcium dobesilate (CaD) to detect its effects. The authors subsequently measured HUVEC proliferation via cell counting kit-8 assays. In addition, HUVEC angiogenesis was investigated via migration assays and fluorescein isothiocyanate (FITC)-labelled bovine serum albumin (BSA) permeability assays. The content or distribution of markers of endothelial dysfunction [vascular endothelial growth factor (VEGF), VEGF receptor (R) and endocan) or inflammation [intercellular adhesion molecule (ICAM)-1, monocyte chemotactic protein (MCP)-1 and pentraxin-related protein (PTX3)] was evaluated via reverse transcription-quantitative polymerase chain reaction and western blotting. HG treatment induced increased in VEGF, VEGFR, endocan, ICAM-1, MCP-1 and PTX3 mRNA and protein expression in HUVECs. HG treatment for 24 to 48 h increased cell proliferation in a time-dependent manner, but the cell proliferation rate was decreased at 72 h of HG treatment. Conversely, CaD inhibited abnormal cell proliferation. HG treatment also significantly enhanced HVUEC migration compared to the control treatment. In contrast, CaD treatment partially inhibited HUVEC migration compared to HG exposure. HG-treated HUVECs exhibited increased FITC-BSA permeability compared to control cells cultured in medium alone; however, CaD application prevented the HG-induced increase in FITC-BSA permeability and suppressed HG-induced overexpression of endothelial markers (VEGF, VEGFR-2

  2. Calcium-pH crosstalks in rat mast cells: cytosolic alkalinization, but not intracellular calcium release, is a sufficient signal for degranulation

    PubMed Central

    Alfonso, A; Cabado, A G; Vieytes, M R; Botana, L M

    2000-01-01

    The aim of this work was to study the relationship between intracellular alkalinization, calcium fluxes and histamine release in rat mast cells. Intracellular alkalinization was induced by nigericin, a monovalent cation ionophore, and by NH4Cl (ammonium chloride). Calcium cytosolic and intracellular pH were measured by fluorescence digital imaging using Fura-2-AM and BCECF-AM.In rat mast cells, nigericin and NH4Cl induce a dose-dependent intracellular alkalinization, a dose-dependent increase in intracellular calcium levels by releasing calcium from intracellular pools, and an activation of capacitative calcium influx.The increase in both intracellular calcium and pH activates exocytosis (histamine release) in the absence of external calcium. Under the same conditions, thapsigargin does not activate exocytosis, the main difference being that thapsigargin does not alkalinize the cytosol.After alkalinization, histamine release is intracellular-calcium dependent. With 2.5 mM EGTA and thapsigargin the cell response decreases by 62%.The cytosolic alkalinization, in addition to the calcium increase it is enough signal to elicit the exocytotic process in rat mast cells. PMID:10952669

  3. Investigations of calcium spectral lines in laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Ching, Sim Yit; Tariq, Usman; Haider, Zuhaib; Tufail, Kashif; Sabri, Salwanie; Imran, Muhammad; Ali, Jalil

    2017-03-01

    Laser-induced breakdown spectroscopy (LIBS) is a direct and versatile analytical technique that performs the elemental composition analysis based on optical emission produced by laser induced-plasma, with a little or no sample preparation. The performance of the LIBS technique relies on the choice of experimental conditions which must be thoroughly explored and optimized for each application. The main parameters affecting the LIBS performance are the laser energy, laser wavelength, pulse duration, gate delay, geometrical set-up of the focusing and collecting optics. In LIBS quantitative analysis, the gate delay and laser energy are very important parameters that have pronounced impact on the accuracy of the elemental composition information of the materials. The determination of calcium elements in the pelletized samples was investigated and served for the purpose of optimizing the gate delay and laser energy by studying and analyzing the results from emission intensities collected and signal to background ratio (S/B) for the specified wavelengths.

  4. Therapeutic role of calcium and vitamin K3 in chemically induced hepatocarcinogenesis - new tools for cancer treatment.

    PubMed

    Anwar, Firoz; Khan, Ruqaiyah; Sachan, Richa; Kazmi, Imran; Rawat, Alisha; Sabih, Abdullah; Singh, Rajbala; Afzal, Muhammad; Ahmad, Aftab; Al-Orab, Abdulaziz S; Al-Abbasi, F A; Bhatt, Prakash Chandra; Kumar, Vikas

    2018-04-17

    HCC has been reported to be immensely occurring carcinoma worldwide. Recent days the mortality occurred due to liver cancer has also been found to be increased at an alarming speed affecting mostly the young patients. The aim of the current study was to decipher the role of calcium and vitamin K3 in the treatment of chemically induced hepatocarcinogenesis in the male Wistar rats. Liver cancer was induced via a subnecrogenic dose of 160 mg/kg body weight, diethylnitrosamine (DENA) when associated with fasting/refeeding in male Wistar rats. It elevated the serum glutamate oxaloacetate (SGOT), serum glutamate pyruvate transaminase (SGPT), alkaline phosphatase (ALP), bilirubin, total cholesterol (CH), triglycerides (TG), alfa-fetoprotein (AFP) and reduced high-density lipoprotein (HDL). Histopathological examination of liver tissue showed marked carcinogenicity of the chemical carcinogen. Food, water intake and animal weights were also assessed, respectively. The animals exposed to DENA showed a significant decrease in the body weight. The elevated levels of serum SGOT, SGPT, ALP, AFP, TC and TG were restored by administration of calcium and Vit K (ad libitum) combination at higher dose than the normal dietary requirement (3 mg/kg) daily for 12 weeks p.o. Physiological and biochemical analysis showed the beneficial effects of calcium and vitamin K3 combination in the animals exposed to DENA. The results deciphered the beneficial effects of calcium and vitamin K3 in combination.

  5. Distant homologs of anti-apoptotic factor HAX1 encode parvalbumin-like calcium binding proteins.

    PubMed

    Kokoszyńska, Katarzyna; Rychlewski, Leszek; Wyrwicz, Lucjan S

    2010-07-15

    Apoptosis is a highly ordered and orchestrated multiphase process controlled by the numerous cellular and extra-cellular signals, which executes the programmed cell death via release of cytochrome c alterations in calcium signaling, caspase-dependent limited proteolysis and DNA fragmentation. Besides the general modifiers of apoptosis, several tissue-specific regulators of this process were identified including HAX1 (HS-1 associated protein X-1) - an anti-apoptotic factor active in myeloid cells. Although HAX1 was the subject of various experimental studies, the mechanisms of its action and a functional link connected with the regulation of apoptosis still remains highly speculative. Here we provide the data which suggests that HAX1 may act as a regulator or as a sensor of calcium. On the basis of iterative similarity searches, we identified a set of distant homologs of HAX1 in insects. The applied fold recognition protocol gives us strong evidence that the distant insects' homologs of HAX1 are novel parvalbumin-like calcium binding proteins. Although the whole three EF-hands fold is not preserved in vertebrate our analysis suggests that there is an existence of a potential single EF-hand calcium binding site in HAX1. The molecular mechanism of its action remains to be identified, but the risen hypothesis easily translates into previously reported lines of various data on the HAX1 biology as well as, provides us a direct link to the regulation of apoptosis. Moreover, we also report that other family of myeloid specific apoptosis regulators - myeloid leukemia factors (MLF1, MLF2) share the homologous C-terminal domain and taxonomic distribution with HAX1. Performed structural and active sites analyses gave new insights into mechanisms of HAX1 and MLF families in apoptosis process and suggested possible role of HAX1 in calcium-binding, still the analyses require further experimental verification.

  6. Distant homologs of anti-apoptotic factor HAX1 encode parvalbumin-like calcium binding proteins

    PubMed Central

    2010-01-01

    Background Apoptosis is a highly ordered and orchestrated multiphase process controlled by the numerous cellular and extra-cellular signals, which executes the programmed cell death via release of cytochrome c alterations in calcium signaling, caspase-dependent limited proteolysis and DNA fragmentation. Besides the general modifiers of apoptosis, several tissue-specific regulators of this process were identified including HAX1 (HS-1 associated protein X-1) - an anti-apoptotic factor active in myeloid cells. Although HAX1 was the subject of various experimental studies, the mechanisms of its action and a functional link connected with the regulation of apoptosis still remains highly speculative. Findings Here we provide the data which suggests that HAX1 may act as a regulator or as a sensor of calcium. On the basis of iterative similarity searches, we identified a set of distant homologs of HAX1 in insects. The applied fold recognition protocol gives us strong evidence that the distant insects' homologs of HAX1 are novel parvalbumin-like calcium binding proteins. Although the whole three EF-hands fold is not preserved in vertebrate our analysis suggests that there is an existence of a potential single EF-hand calcium binding site in HAX1. The molecular mechanism of its action remains to be identified, but the risen hypothesis easily translates into previously reported lines of various data on the HAX1 biology as well as, provides us a direct link to the regulation of apoptosis. Moreover, we also report that other family of myeloid specific apoptosis regulators - myeloid leukemia factors (MLF1, MLF2) share the homologous C-terminal domain and taxonomic distribution with HAX1. Conclusions Performed structural and active sites analyses gave new insights into mechanisms of HAX1 and MLF families in apoptosis process and suggested possible role of HAX1 in calcium-binding, still the analyses require further experimental verification. PMID:20633251

  7. Cytosolic calcium rises and related events in ergosterol-treated Nicotiana cells.

    PubMed

    Vatsa, Parul; Chiltz, Annick; Luini, Estelle; Vandelle, Elodie; Pugin, Alain; Roblin, Gabriel

    2011-07-01

    The typical fungal membrane component ergosterol was previously shown to trigger defence responses and protect plants against pathogens. Most of the elicitors mobilize the second messenger calcium, to trigger plant defences. We checked the involvement of calcium in response to ergosterol using Nicotiana plumbaginifolia and Nicotiana tabacum cv Xanthi cells expressing apoaequorin in the cytosol. First, it was verified if ergosterol was efficient in these cells inducing modifications of proton fluxes and increased expression of defence-related genes. Then, it was shown that ergosterol induced a rapid and transient biphasic increase of free [Ca²⁺](cyt) which intensity depends on ergosterol concentration in the range 0.002-10 μM. Among sterols, this calcium mobilization was specific for ergosterol and, ergosterol-induced pH and [Ca²⁺](cyt) changes were specifically desensitized after two subsequent applications of ergosterol. Specific modulators allowed elucidating some events in the signalling pathway triggered by ergosterol. The action of BAPTA, LaCl₃, nifedipine, verapamil, neomycin, U73122 and ruthenium red suggested that the first phase was linked to calcium influx from external medium which subsequently triggered the second phase linked to calcium release from internal stores. The calcium influx and the [Ca²⁺](cyt) increase depended on upstream protein phosphorylation. The extracellular alkalinization and ROS production depended on calcium influx but, the ergosterol-induced MAPK activation was calcium-independent. ROS were not involved in cytosolic calcium rise as described in other models, indicating that ROS do not systematically participate in the amplification of calcium signalling. Interestingly, ergosterol-induced ROS production is not linked to cell death and ergosterol does not induce any calcium elevation in the nucleus. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  8. Multiple receptors mobilize calcium through a pertussis toxin (PT) sensitive GTP-binding protein in human neutrophils (PMN's)

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

    Lad, P.M.; Olson, C.V.; Grewal, I.S.

    1986-03-05

    Treatment of PMN's with PT causes an abolition of chemotaxis, enzyme release, superoxide generation and aggregation caused by f-met-leu-phe (FMLP),C5a and platelet activating factor (PAF). Lectin (Con-A) induced capping and receptor induced shape change are abolished, but phagocytosis is unaltered. In whole cells, calcium mobilization induced by FMLP, PAF and Con-A inhibited by PT although the FMLP-mediated effect is more susceptible to PT's effects. Treatment of PMN's with phorbol 12-myristate 13 acetate (PMA) causes an abolition of calcium mobilization by all agents in a range which also inhibits cap formation. Investigation of calcium uptake reveals PT sensitive and insensitive components.more » Reciprocal interactions between Ns and Ni proteins are also observed since pretreatment with FMLP and PAF causes a stimulation of Ns-mediated cyclic AMP enhancement while pretreatment with Ns linked receptors (PGE/sub 1/ and beta receptor agonists) inhibits calcium mobilization. Comparative peptide mapping studies indicate substantial similarity between Ni proteins in PMN's, platelets and human erythrocytes. The authors results suggest that the Ni linked calcium mobilization sensitive to PMA is important to the regulation of the human neutrophil.« less

  9. Real-time scratch assay reveals mechanisms of early calcium signaling in breast cancer cells in response to wounding

    PubMed Central

    Pratt, Stephen J.P.; Hernández-Ochoa, Erick O.; Lee, Rachel M.; Ory, Eleanor C.; Lyons, James S.; Joca, Humberto C.; Johnson, Ashley; Thompson, Keyata; Bailey, Patrick; Lee, Cornell J.; Mathias, Trevor; Vitolo, Michele I.; Trudeau, Matt; Stains, Joseph P.; Ward, Christopher W.; Schneider, Martin F.; Martin, Stuart S.

    2018-01-01

    Aggressive cellular phenotypes such as uncontrolled proliferation and increased migration capacity engender cellular transformation, malignancy and metastasis. While genetic mutations are undisputed drivers of cancer initiation and progression, it is increasingly accepted that external factors are also playing a major role. Two recently studied modulators of breast cancer are changes in the cellular mechanical microenvironment and alterations in calcium homeostasis. While many studies investigate these factors separately in breast cancer cells, very few do so in combination. This current work sets a foundation to explore mechano-calcium relationships driving malignant progression in breast cancer. Utilizing real-time imaging of an in vitro scratch assay, we were able to resolve mechanically-sensitive calcium signaling in human breast cancer cells. We observed rapid initiation of intracellular calcium elevations within seconds in cells at the immediate wound edge, followed by a time-dependent increase in calcium in cells at distances up to 500μm from the scratch wound. Calcium signaling to neighboring cells away from the wound edge returned to baseline within seconds. Calcium elevations at the wound edge however, persisted for up to 50 minutes. Rigorous quantification showed that extracellular calcium was necessary for persistent calcium elevation at the wound edge, but intercellular signal propagation was dependent on internal calcium stores. In addition, intercellular signaling required extracellular ATP and activation of P2Y2 receptors. Through comparison of scratch-induced signaling from multiple cell lines, we report drastic reductions in response from aggressively tumorigenic and metastatic cells. The real-time scratch assay established here provides quantitative data on the molecular mechanisms that support rapid scratch-induced calcium signaling in breast cancer cells. These mechanisms now provide a clear framework for investigating which short-term calcium

  10. Characterization of L-type calcium channel activity in atrioventricular nodal myocytes from rats with streptozotocin-induced Diabetes mellitus

    PubMed Central

    Yuill, Kathryn H; Al Kury, Lina T; Howarth, Frank Christopher

    2015-01-01

    Cardiovascular complications are common in patients with Diabetes mellitus (DM). In addition to changes in cardiac muscle inotropy, electrical abnormalities are also commonly observed in these patients. We have previously shown that spontaneous cellular electrical activity is altered in atrioventricular nodal (AVN) myocytes, isolated from the streptozotocin (STZ) rat model of type-1 DM. In this study, utilizing the same model, we have characterized the changes in L-type calcium channel activity in single AVN myocytes. Ionic currents were recorded from AVN myocytes isolated from the hearts of control rats and from those with STZ-induced diabetes. Patch-clamp recordings were used to assess the changes in cellular electrical activity in individual myocytes. Type-1 DM significantly altered the cellular characteristics of L-type calcium current. A reduction in peak ICaL density was observed, with no corresponding changes in the activation parameters of the current. L-type calcium channel current also exhibited faster time-dependent inactivation in AVN myocytes from diabetic rats. A negative shift in the voltage dependence of inactivation was also evident, and a slowing of restitution parameters. These findings demonstrate that experimentally induced type-1 DM significantly alters AVN L-type calcium channel cellular electrophysiology. These changes in ion channel activity may contribute to the abnormalities in cardiac electrical function that are associated with high mortality levels in patients with DM. PMID:26603460

  11. Calcium-mediated responses and glutamine synthetase expression in greater duckweed (Spirodela polyrhiza L.) under diethyl phthalate-induced stress.

    PubMed

    Cheng, Lee-Ju; Hung, Meng-Ju; Cheng, Yen-I; Cheng, Tai-Sheng

    2013-11-15

    This study was carried out to assess the influence of diethyl phthalate (DEP) alone or associated with calcium chloride (CaCl2) on greater duckweed plants, emphasizing the implications of calcium in amelioration of DEP-induced stress on plant growth. Greater duckweed were treated with DEP in variable concentrations, as 0, 0.25, 0.5, 1.0 and 2.0mM for 7 days, or treated with the same concentration either 2mM DEP or 2mM DEP plus 10mM CaCl2·2H2O in different duration 0-7 days. Treatment with 2mM DEP resulted in increasing proline content, protease activity, and ammonia accumulation in duckweed tissues. NADH-glutamate dehydrogenase (NADH-GDH; EC 1.4.1.2) and Δ(1)-pyrroline-5-carboxylate reductase (P5CR; EC 1.5.1.2), two key enzymes in the glutamate pathway of proline synthesis, showed increase in activity with DEP treatment and positively correlated with proline accumulation. No further increase in proline accumulation was observed with addition of calcium chloride to the DEP-treated cultures. However, supplementation of Ca(2+) can mitigate the adverse effect of DEP, at least in part to decrease the DEP-induced superoxide accumulation and increase in GDH activity for ammonia assimilation in duckweed fronds. In addition, effects of calcium on mitigation of DEP injury were also observed in glutamine synthetase (GS; EC 6.3.1.2) expression. Both GS1 and GS2 polypeptide accumulation and the level of total GS activity were nearly equivalent to the control. Exogenous proline protects GS2 from DEP-modulated redox damage in the chloroplast lysates but there is no remarkable protection effects on D1 (the 32kDa protein in photosystem II reaction center) degradation. In conclusion, the glutamate pathway of proline synthesis might be involved in mitigation of DEP-induced injury, and calcium plays an important role in increasing GDH, P5CR, and GS expression. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Aphanomyces euteiches cell wall fractions containing novel glucan-chitosaccharides induce defense genes and nuclear calcium oscillations in the plant host Medicago truncatula.

    PubMed

    Nars, Amaury; Lafitte, Claude; Chabaud, Mireille; Drouillard, Sophie; Mélida, Hugo; Danoun, Saïda; Le Costaouëc, Tinaig; Rey, Thomas; Benedetti, Julie; Bulone, Vincent; Barker, David George; Bono, Jean-Jacques; Dumas, Bernard; Jacquet, Christophe; Heux, Laurent; Fliegmann, Judith; Bottin, Arnaud

    2013-01-01

    N-acetylglucosamine-based saccharides (chitosaccharides) are components of microbial cell walls and act as molecular signals during host-microbe interactions. In the legume plant Medicago truncatula, the perception of lipochitooligosaccharide signals produced by symbiotic rhizobia and arbuscular mycorrhizal fungi involves the Nod Factor Perception (NFP) lysin motif receptor-like protein and leads to the activation of the so-called common symbiotic pathway. In rice and Arabidopsis, lysin motif receptors are involved in the perception of chitooligosaccharides released by pathogenic fungi, resulting in the activation of plant immunity. Here we report the structural characterization of atypical chitosaccharides from the oomycete pathogen Aphanomyces euteiches, and their biological activity on the host Medicago truncatula. Using a combination of biochemical and biophysical approaches, we show that these chitosaccharides are linked to β-1,6-glucans, and contain a β-(1,3;1,4)-glucan backbone whose β-1,3-linked glucose units are substituted on their C-6 carbon by either glucose or N-acetylglucosamine residues. This is the first description of this type of structural motif in eukaryotic cell walls. Glucan-chitosaccharide fractions of A. euteiches induced the expression of defense marker genes in Medicago truncatula seedlings independently from the presence of a functional Nod Factor Perception protein. Furthermore, one of the glucan-chitosaccharide fractions elicited calcium oscillations in the nucleus of root cells. In contrast to the asymmetric oscillatory calcium spiking induced by symbiotic lipochitooligosaccharides, this response depends neither on the Nod Factor Perception protein nor on the common symbiotic pathway. These findings open new perspectives in oomycete cell wall biology and elicitor recognition and signaling in legumes.

  13. Aphanomyces euteiches Cell Wall Fractions Containing Novel Glucan-Chitosaccharides Induce Defense Genes and Nuclear Calcium Oscillations in the Plant Host Medicago truncatula

    PubMed Central

    Nars, Amaury; Lafitte, Claude; Chabaud, Mireille; Drouillard, Sophie; Mélida, Hugo; Danoun, Saïda; Le Costaouëc, Tinaig; Rey, Thomas; Benedetti, Julie; Bulone, Vincent; Barker, David George; Bono, Jean-Jacques; Dumas, Bernard; Jacquet, Christophe; Heux, Laurent; Fliegmann, Judith; Bottin, Arnaud

    2013-01-01

    N-acetylglucosamine-based saccharides (chitosaccharides) are components of microbial cell walls and act as molecular signals during host-microbe interactions. In the legume plant Medicago truncatula, the perception of lipochitooligosaccharide signals produced by symbiotic rhizobia and arbuscular mycorrhizal fungi involves the Nod Factor Perception (NFP) lysin motif receptor-like protein and leads to the activation of the so-called common symbiotic pathway. In rice and Arabidopsis, lysin motif receptors are involved in the perception of chitooligosaccharides released by pathogenic fungi, resulting in the activation of plant immunity. Here we report the structural characterization of atypical chitosaccharides from the oomycete pathogen Aphanomyces euteiches, and their biological activity on the host Medicago truncatula. Using a combination of biochemical and biophysical approaches, we show that these chitosaccharides are linked to β-1,6-glucans, and contain a β-(1,3;1,4)-glucan backbone whose β-1,3-linked glucose units are substituted on their C-6 carbon by either glucose or N-acetylglucosamine residues. This is the first description of this type of structural motif in eukaryotic cell walls. Glucan-chitosaccharide fractions of A. euteiches induced the expression of defense marker genes in Medicago truncatula seedlings independently from the presence of a functional Nod Factor Perception protein. Furthermore, one of the glucan-chitosaccharide fractions elicited calcium oscillations in the nucleus of root cells. In contrast to the asymmetric oscillatory calcium spiking induced by symbiotic lipochitooligosaccharides, this response depends neither on the Nod Factor Perception protein nor on the common symbiotic pathway. These findings open new perspectives in oomycete cell wall biology and elicitor recognition and signaling in legumes. PMID:24086432

  14. Effects of Orthosiphon grandiflorus, Hibiscus sabdariffa and Phyllanthus amarus extracts on risk factors for urinary calcium oxalate stones in rats.

    PubMed

    Woottisin, Surachet; Hossain, Rayhan Zubair; Yachantha, Chatchai; Sriboonlue, Pote; Ogawa, Yoshihide; Saito, Seiichi

    2011-01-01

    We evaluated the antilithic effect of Orthosiphon grandiflorus, Hibiscus sabdariffa and Phyllanthus amarus extracts on known risk factors for calcium oxalate stones in rats. We divided 30 male Wistar rats into 5 equal groups. Controls were fed a standard diet and the remaining groups received a 3% glycolate diet for 4 weeks to induce hyperoxaluria. One glycolate fed group served as the untreated group and the others were given oral extracts of Orthosiphon grandiflorus, Hibiscus sabdariffa or Phyllanthus amarus at a dose of 3.5 mg daily. We collected 24-hour urine and blood samples. Kidneys were harvested for histological examination. We measured the renal tissue content of calcium and oxalate. The Hibiscus sabdariffa group showed significantly decreased serum oxalate and glycolate, and higher oxalate urinary excretion. The Phyllanthus amarus group showed significantly increased urinary citrate vs the untreated group. Histological examination revealed less CaOx crystal deposition in the kidneys of Hibiscus sabdariffa and Phyllanthus amarus treated rats than in untreated rats. Those rats also had significantly lower renal tissue calcium content than untreated rats. All parameters in the Orthosiphon grandiflorus treated group were comparable to those in the untreated group. Hibiscus sabdariffa and Phyllanthus amarus decreased calcium crystal deposition in the kidneys. The antilithic effect of Hibiscus sabdariffa may be related to decreased oxalate retention in the kidney and more excretion into urine while that of Phyllanthus amarus may depend on increased urinary citrate. In contrast, administering Orthosiphon grandiflorus had no antilithic effect. Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  15. Complete genome sequence of Lysinibacillus sphaericus LMG 22257, a strain with ureolytic activity inducing calcium carbonate precipitation.

    PubMed

    Yan, Wenkai; Xiao, Xiang; Zhang, Yu

    2017-03-20

    Microbiologically induced calcium carbonate precipitation shows the potential for use in bioremediation and construction consolidation, but the efficiency of this process must be improved. Lysinibacillus sphaericus LMG 22257 is a gram-positive ureolytic strain that has recently been applied for consolidating construction by mediating calcium carbonate precipitation. The complete genome sequence of L. sphaericus LMG 22257 is 3,436,578 base pairs with a GC content of 38.99%. The urea degradation pathway and genes related to extracellular polymeric substance biosynthesis were also identified. The strain can tolerate high alkalinity (pH up to 10) and high urea concentration (up to 3M). These findings provide insights into the microbiologically induced carbonate precipitation and extend the application of the metabolic potential of L. sphaericus LMG 22257 for bioremediation. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Aberrant Splicing Induced by Dysregulated Rbfox2 Produces Enhanced Function of CaV1.2 Calcium Channel and Vascular Myogenic Tone in Hypertension.

    PubMed

    Zhou, Yingying; Fan, Jia; Zhu, Huayuan; Ji, Li; Fan, Wenyong; Kapoor, Isha; Wang, Yue; Wang, Yuan; Zhu, Guoqing; Wang, Juejin

    2017-12-01

    Calcium influx from activated voltage-gated calcium channel Ca V 1.2 in vascular smooth muscle cells is indispensable for maintaining myogenic tone and blood pressure. The function of Ca V 1.2 channel can be optimized by alternative splicing, one of post-transcriptional modification mechanisms. The splicing factor Rbfox2 is known to regulate the Ca V 1.2 pre-mRNA alternative splicing events during neuronal development. However, Rbfox2's roles in modulating the key function of vascular Ca V 1.2 channel and in the pathogenesis of hypertension remain elusive. Here, we report that the proportion of Ca V 1.2 channels with alternative exon 9* is increased by 10.3%, whereas that with alternative exon 33 is decreased by 10.5% in hypertensive arteries. Surprisingly, the expression level of Rbfox2 is increased ≈3-folds, presumably because of the upregulation of a dominant-negative isoform of Rbfox2. In vascular smooth muscle cells, we find that knockdown of Rbfox2 dynamically increases alternative exon 9*, whereas decreases exon 33 inclusion of Ca V 1.2 channels. By patch-clamp studies, we show that diminished Rbfox2-induced alternative splicing shifts the steady-state activation and inactivation curves of vascular Ca V 1.2 calcium channel to hyperpolarization, which makes the window current potential to more negative. Moreover, siRNA-mediated knockdown of Rbfox2 increases the pressure-induced vascular myogenic tone of rat mesenteric artery. Taken together, our data indicate that Rbfox2 modulates the functions of vascular Ca V 1.2 calcium channel by dynamically regulating the expressions of alternative exons 9* and 33, which in turn affects the vascular myogenic tone. Therefore, our work suggests a key role for Rbfox2 in hypertension, which provides a rational basis for designing antihypertensive therapies. © 2017 American Heart Association, Inc.

  17. Supplemental calcium and risk reduction of hypertension, pregnancy-induced hypertension, and preeclampsia: an evidence-based review by the US Food and Drug Administration.

    PubMed

    Trumbo, Paula R; Ellwood, Kathleen C

    2007-02-01

    The labeling of health claims that meet the significant scientific agreement (SSA) standard (authorized health claims) and qualified health claims on conventional foods and dietary supplements requires premarket approval by the US Food and Drug Administration (FDA). FDA conducts an evidence-based review to determine whether there is sufficient evidence to support an authorized or qualified health claim. An evidence-based review was conducted on the human intervention and observational studies evaluating the role of supplemental calcium in reducing the risk of hypertension, pregnancy-induced hypertension, and preeclampsia. This review provides FDA's evaluation of the current scientific evidence on the role of supplemental calcium in reducing the risk of these three end points. Based on this evidence-based review, the agency concluded that the relationship between calcium and risk of hypertension is inconsistent and inconclusive, and the relationship between calcium and risk of pregnancy-induced hypertension and preeclampsia is highly unlikely.

  18. Effect of oral calcium and calcium + fluoride treatments on mouse bone properties during suspension

    NASA Technical Reports Server (NTRS)

    Simske, S. J.; Luttges, M. W.; Allen, K. A.; Spooner, B. S. (Principal Investigator)

    1992-01-01

    The bone effects of oral dosages of calcium chloride with or without supplementary sodium fluoride were assessed in antiorthostatically suspended mice. Two calcium dosages were used to replace half (3.1 mM) or all(6.3 mM) of the dietary calcium lost due to reduced food intake by the suspended mice. Two groups of 6.3 mM CaCl2-treated mice were additionally treated with 0.25 or 2.5 mM NaF. The results indicate that supplementation of the mouse drinking water with calcium salts prevents bone changes induced by short-term suspension, while calcium salts in combination with fluoride are less effective as fluoride dosage increases. However, the calcium supplements change the relationship between the femur mechanical properties and the mineral composition of the bone. Because of this, it appears that oral calcium supplements are effective through a mechanism other than simple dietary supplementation and may indicate a dependence of bone consistency on systemic and local fluid conditions.

  19. Autophagy inhibition attenuates hyperoxaluria-induced renal tubular oxidative injury and calcium oxalate crystal depositions in the rat kidney.

    PubMed

    Duan, Xiaolu; Kong, Zhenzhen; Mai, Xin; Lan, Yu; Liu, Yang; Yang, Zhou; Zhao, Zhijian; Deng, Tuo; Zeng, Tao; Cai, Chao; Li, Shujue; Zhong, Wen; Wu, Wenqi; Zeng, Guohua

    2018-06-01

    Hyperoxaluria-induced oxidative injury of renal tubular epithelial cell is a casual and essential factor in kidney calcium oxalate (CaOx) stone formation. Autophagy has been shown to be critical for the regulation of oxidative stress-induced renal tubular injury; however, little is known about its role in kidney CaOx stone formation. In the present study, we found that the autophagy antagonist chloroquine could significantly attenuate oxalate-induced autophagy activation, oxidative injury and mitochondrial damage of renal tubular cells in vitro and in vivo, as well as hyperoxaluria-induced CaOx crystals depositions in rat kidney, whereas the autophagy agonist rapamycin exerted contrasting effects. In addition, oxalate-induced p38 phosphorylation was significantly attenuated by chloroquine pretreatment but was markedly enhanced by rapamycin pretreatment, whereas the protective effect of chloroquine on rat renal tubular cell oxidative injury was partly reversed by a p38 protein kinase activator anisomycin. Furthermore, the knockdown of Beclin1 represented similar effects to chloroquine on oxalate-induced cell oxidative injury and p38 phosphorylation in vitro. Taken together, our results revealed that autophagy inhibition could attenuate oxalate-induced oxidative injury of renal tubular cell and CaOx crystal depositions in the rat kidney via, at least in part, inhibiting the activation of p38 signaling pathway, thus representing a novel role of autophagy in the regulation of oxalate-induced renal oxidative injury and CaOx crystal depositions for the first time. Copyright © 2018. Published by Elsevier B.V.

  20. Construction of two ureolytic model organisms for the study of microbially induced calcium carbonate precipitation.

    PubMed

    Connolly, James; Kaufman, Megan; Rothman, Adam; Gupta, Rashmi; Redden, George; Schuster, Martin; Colwell, Frederick; Gerlach, Robin

    2013-09-01

    Two bacterial strains, Pseudomonas aeruginosa MJK1 and Escherichia coli MJK2, were constructed that both express green fluorescent protein (GFP) and carry out ureolysis. These two novel model organisms are useful for studying bacterial carbonate mineral precipitation processes and specifically ureolysis-driven microbially induced calcium carbonate precipitation (MICP). The strains were constructed by adding plasmid-borne urease genes (ureABC, ureD and ureFG) to the strains P. aeruginosa AH298 and E. coli AF504gfp, both of which already carried unstable GFP derivatives. The ureolytic activities of the two new strains were compared to the common, non-GFP expressing, model organism Sporosarcina pasteurii in planktonic culture under standard laboratory growth conditions. It was found that the engineered strains exhibited a lower ureolysis rate per cell but were able to grow faster and to a higher population density under the conditions of this study. Both engineered strains were successfully grown as biofilms in capillary flow cell reactors and ureolysis-induced calcium carbonate mineral precipitation was observed microscopically. The undisturbed spatiotemporal distribution of biomass and calcium carbonate minerals were successfully resolved in 3D using confocal laser scanning microscopy. Observations of this nature were not possible previously because no obligate urease producer that expresses GFP had been available. Future observations using these organisms will allow researchers to further improve engineered application of MICP as well as study natural mineralization processes in model systems. © 2013.

  1. Calcium antagonists and deep gingival pockets in the population-based SHIP study

    PubMed Central

    Meisel, Peter; Schwahn, Christian; John, Ulrich; Kroemer, Heyo K; Kocher, Thomas

    2005-01-01

    Aim Gingival overgrowth is a common undesired side-effect in patients taking calcium channel blockers. Different reports have suggested that the drug-induced gingival hyperplasia may aggravate inflammatory periodontal disease. However, representative epidemiological data are lacking. We investigated the association between the intake of calcium antagonists and periodontitis in a population-based analysis including the most important risk factors of periodontitis. Methods In a cross-sectional epidemiological investigation involving 4290 subjects aged 20–80 years, we recorded periodontal risk factors and identified participants using calcium antagonists. Periodontal parameters, attachment loss, probing depth and number of teeth were assessed. In a subgroup analysis with matched pairs, 456 subjects using calcium antagonists and 456 without were compared for periodontal status. Results Subjects treated with calcium antagonistic drugs had significantly deeper gingival pockets than their drug-free counterparts. This was observed in the total population of 4290 and confirmed by logistic regression analyses (P < 0.001) controlled for the known risk factors of periodontitis (age, sex, smoking, education). In the matched-pair analysis only the probing depth was increased: extent probing depth ≥4 mm median 23.5 vs. 17.0% (P < 0.001); mean probing depth 3.0 ± 0.8 vs. 2.7 ± 0.9 mm (P < 0.001). No differences were found in extent and severity of clinical attachment loss and in the number of teeth. The risk of gingival overgrowth was aggravated in smokers. Conclusion In the general population, treatment with calcium antagonists leads to gingival overgrowth without an aggravation of periodontal disease. Interaction with smoking indicates the multifactorial background of the undesired effect of calcium antagonists. PMID:16236046

  2. Calcium Nutrition and Extracellular Calcium Sensing: Relevance for the Pathogenesis of Osteoporosis, Cancer and Cardiovascular Diseases

    PubMed Central

    Peterlik, Meinrad; Kállay, Enikoe; Cross, Heide S.

    2013-01-01

    Through a systematic search in Pubmed for literature, on links between calcium malnutrition and risk of chronic diseases, we found the highest degree of evidence for osteoporosis, colorectal and breast cancer, as well as for hypertension, as the only major cardiovascular risk factor. Low calcium intake apparently has some impact also on cardiovascular events and disease outcome. Calcium malnutrition can causally be related to low activity of the extracellular calcium-sensing receptor (CaSR). This member of the family of 7-TM G-protein coupled receptors allows extracellular Ca2+ to function as a “first messenger” for various intracellular signaling cascades. Evidence demonstrates that Ca2+/CaSR signaling in functional linkage with vitamin D receptor (VDR)-activated pathways (i) promotes osteoblast differentiation and formation of mineralized bone; (ii) targets downstream effectors of the canonical and non-canonical Wnt pathway to inhibit proliferation and induce differentiation of colorectal cancer cells; (iii) evokes Ca2+ influx into breast cancer cells, thereby activating pro-apoptotic intracellular signaling. Furthermore, Ca2+/CaSR signaling opens Ca2+-sensitive K+ conductance channels in vascular endothelial cells, and also participates in IP3-dependent regulation of cytoplasmic Ca2+, the key intermediate of cardiomyocyte functions. Consequently, impairment of Ca2+/CaSR signaling may contribute to inadequate bone formation, tumor progression, hypertension, vascular calcification and, probably, cardiovascular disease. PMID:23340319

  3. Nuclear Calcium Signaling Controls Expression of a Large Gene Pool: Identification of a Gene Program for Acquired Neuroprotection Induced by Synaptic Activity

    PubMed Central

    Zhang, Sheng-Jia; Zou, Ming; Lu, Li; Lau, David; Ditzel, Désirée A. W.; Delucinge-Vivier, Celine; Aso, Yoshinori; Descombes, Patrick; Bading, Hilmar

    2009-01-01

    Synaptic activity can boost neuroprotection through a mechanism that requires synapse-to-nucleus communication and calcium signals in the cell nucleus. Here we show that in hippocampal neurons nuclear calcium is one of the most potent signals in neuronal gene expression. The induction or repression of 185 neuronal activity-regulated genes is dependent upon nuclear calcium signaling. The nuclear calcium-regulated gene pool contains a genomic program that mediates synaptic activity-induced, acquired neuroprotection. The core set of neuroprotective genes consists of 9 principal components, termed Activity-regulated Inhibitor of Death (AID) genes, and includes Atf3, Btg2, GADD45β, GADD45γ, Inhibin β-A, Interferon activated gene 202B, Npas4, Nr4a1, and Serpinb2, which strongly promote survival of cultured hippocampal neurons. Several AID genes provide neuroprotection through a common process that renders mitochondria more resistant to cellular stress and toxic insults. Stereotaxic delivery of AID gene-expressing recombinant adeno-associated viruses to the hippocampus confers protection in vivo against seizure-induced brain damage. Thus, treatments that enhance nuclear calcium signaling or supplement AID genes represent novel therapies to combat neurodegenerative conditions and neuronal cell loss caused by synaptic dysfunction, which may be accompanied by a deregulation of calcium signal initiation and/or propagation to the cell nucleus. PMID:19680447

  4. High dietary calcium to phosphorus ratio and alkali-forming potential as factors promoting silica urolithiasis in sheep.

    PubMed

    Stewart, S R; Emerick, R J; Pritchard, R H

    1990-02-01

    Sheep were used to study factors previously found to promote silica urolithiasis in a rat model. In addition to high silica, these dietary factors included elevated calcium, a high calcium to phosphorus ratio and alkali-forming effects. Wether lambs had ad libitum access to a diet of 50% of grass hay and 50% ground oats plus supplement. Diet analysis was 3.4% total SiO2, .29% calcium, .25% phosphorus, 11.3% CP and 28% ADF. Treatments (40 lambs/treatment) consisted of a control (C), limestone to increase dietary calcium to .6% (L), L + 1% sodium bicarbonate (LS) and L + 1% ammonium chloride (LA). After a 91-d experimental period followed by a 56-d postexperimental finishing period, silica kidney deposits were found in all treatments, and SiO2 made up 74% to 97% of the urolithic ash. Kidney urolith incidences in the four treatments were C, 7/40; L, 12/40; LS, 20/40; and LA, 9/40. A higher urolith incidence in LS (LS vs C, P less than .05) and a trend toward a higher incidence in L (L vs C, P less than .2), accompanied by elevated urine pH (L = LS greater than C greater than LA, P less than .01), lend support to the concept that high-silica diets having high calcium to phosphorus ratios and alkali-forming potentials contribute to silica urolithiasis.

  5. Action of aluminum, novel TPC1-type channel inhibitor, against salicylate-induced and cold-shock-induced calcium influx in tobacco BY-2 cells.

    PubMed

    Lin, Cun; Yu, Yawei; Kadono, Takashi; Iwata, Michiaki; Umemura, Kenji; Furuichi, Takuya; Kuse, Masaki; Isobe, Minoru; Yamamoto, Yoko; Matsumoto, Hideaki; Yoshizuka, Kazuharu; Kawano, Tomonori

    2005-07-08

    Previously, effect of Al ions on calcium signaling was assessed in tobacco cells expressing a Ca2+-monitoring luminescent protein, aequorin and a newly isolated putative plant Ca2+ channel protein from Arabidopsis thaliana, AtTPC1 (two-pore channel 1). TPC1 channels were shown to be the only channel known to be sensitive to Al and they are responsive to reactive oxygen species and cryptogein, a fungal elicitor protein. Thus, involvement of TPC1 channels in calcium signaling leading to development of plant defense mechanism has been suggested. Then, the use of Al as a specific inhibitor of TPC1-type plant calcium channels has been proposed. Here, using transgenic tobacco BY-2 cells expressing aequorin, we report on the evidence in support of the involvement of Al-sensitive signaling pathway requiring TPC1-type channel-dependent Ca2+ influx in response to salicylic acid, a key plant defense-inducing agent, but not to an elicitor prepared from the cell wall of rice blast disease fungus Magnaporthe grisea. In addition, involvement of Al-sensitive Ca2+ channels in response to cold shock was also tested. The data suggested that the elicitor used here induces the Ca2+ influx via Al-insensitive path, while salicylic acid and cold-shock-stimulate the influx of Ca2+ via Al-sensitive mechanism.

  6. A new synthetic granular calcium phosphate compound induces new bone in a sinus lift rabbit model.

    PubMed

    Trbakovic, Amela; Hedenqvist, Patricia; Mellgren, Torbjörn; Ley, Cecilia; Hilborn, Jöns; Ossipov, Dmitri; Ekman, Stina; Johansson, Carina B; Jensen-Waern, Marianne; Thor, Andreas

    2018-03-01

    The aim of this study was to investigate if a synthetic granular calcium phosphate compound (CPC) and a composite bisphosphonate-linked hyaluronic acid-calcium phosphate hydrogel (HABP·CaP) induced similar or more amount of bone as bovine mineral in a modified sinus lift rabbit model. Eighteen adult male New Zeeland White rabbits, received randomly one of the two test materials on a random side of the face, and bovine mineral as control on the contralateral side. In a sinus lift, the sinus mucosa was elevated and a titanium mini-implant was placed in the alveolar bone. Augmentation material (CPC, HABP·CaP or bovine bone) was applied in the space around the implant. The rabbits were euthanized three months after surgery and qualitative and histomorphometric evaluation were conducted. Histomorphometric evaluation included three different regions of interest (ROIs) and the bone to implant contact on each installed implant. Qualitative assessment (p = <.05), histomorphometric evaluations (p = < .01), and implant incorporation (p = <.05) showed that CPC and bovine mineral induced similar amount of bone and more than the HABP·CaP hydrogel. CPC induced similar amount of bone as bovine mineral and both materials induced more bone than HABP·CaP hydrogel. The CPC is suggested as a synthetic alternative for augmentations in the maxillofacial area. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Air bubble contact with endothelial cells in vitro induces calcium influx and IP3-dependent release of calcium stores

    PubMed Central

    Sobolewski, Peter; Kandel, Judith; Klinger, Alexandra L.

    2011-01-01

    Gas embolism is a serious complication of decompression events and clinical procedures, but the mechanism of resulting injury remains unclear. Previous work has demonstrated that contact between air microbubbles and endothelial cells causes a rapid intracellular calcium transient and can lead to cell death. Here we examined the mechanism responsible for the calcium rise. Single air microbubbles (50–150 μm), trapped at the tip of a micropipette, were micromanipulated into contact with individual human umbilical vein endothelial cells (HUVECs) loaded with Fluo-4 (a fluorescent calcium indicator). Changes in intracellular calcium were then recorded via epifluorescence microscopy. First, we confirmed that HUVECs rapidly respond to air bubble contact with a calcium transient. Next, we examined the involvement of extracellular calcium influx by conducting experiments in low calcium buffer, which markedly attenuated the response, or by pretreating cells with stretch-activated channel blockers (gadolinium chloride or ruthenium red), which abolished the response. Finally, we tested the role of intracellular calcium release by pretreating cells with an inositol 1,4,5-trisphosphate (IP3) receptor blocker (xestospongin C) or phospholipase C inhibitor (neomycin sulfate), which eliminated the response in 64% and 67% of cases, respectively. Collectively, our results lead us to conclude that air bubble contact with endothelial cells causes an influx of calcium through a stretch-activated channel, such as a transient receptor potential vanilloid family member, triggering the release of calcium from intracellular stores via the IP3 pathway. PMID:21633077

  8. Sphingomyelin-induced inhibition of the plasma membrane calcium ATPase causes neurodegeneration in type A Niemann-Pick disease.

    PubMed

    Pérez-Cañamás, A; Benvegnù, S; Rueda, C B; Rábano, A; Satrústegui, J; Ledesma, M D

    2017-05-01

    Niemann-Pick disease type A (NPA) is a rare lysosomal storage disorder characterized by severe neurological alterations that leads to death in childhood. Loss-of-function mutations in the acid sphingomyelinase (ASM) gene cause NPA, and result in the accumulation of sphingomyelin (SM) in lysosomes and plasma membrane of neurons. Using ASM knockout (ASMko) mice as a NPA disease model, we investigated how high SM levels contribute to neural pathology in NPA. We found high levels of oxidative stress both in neurons from these mice and a NPA patient. Impaired activity of the plasma membrane calcium ATPase (PMCA) increases intracellular calcium. SM induces PMCA decreased activity, which causes oxidative stress. Incubating ASMko-cultured neurons in the histone deacetylase inhibitor, SAHA, restores PMCA activity and calcium homeostasis and, consequently, reduces the increased levels of oxidative stress. No recovery occurs when PMCA activity is pharmacologically impaired or genetically inhibited in vitro. Oral administration of SAHA prevents oxidative stress and neurodegeneration, and improves behavioral performance in ASMko mice. These results demonstrate a critical role for plasma membrane SM in neuronal calcium regulation. Thus, we identify changes in PMCA-triggered calcium homeostasis as an upstream mediator for NPA pathology. These findings can stimulate new approaches for pharmacological remediation in a disease with no current clinical treatments.

  9. Dietary calcium induced cytological and biochemical changes in thyroid.

    PubMed

    Chandra, Amar K; Goswami, Haimanti; Sengupta, Pallav

    2012-09-01

    Certain epidemiological studies revealed correlation between hard water consumption (with high calcium) and thyroid size of the population, though the possible alterations in thyroid physiology upon calcium exposure are still inconclusive. Adult male Wistar strain rats were subjected to calcium treatment at the doses of 0.5g%, 1.0g% and 1.5g% calcium chloride (CaCl(2)) for 60 days. The parameters studied were - thyroid gland weight, histopathology, histomorphometry; thyroid peroxidase (TPO), 5'-deiodinase I (DI), sodium-potassium adenosine triphosphatase (Na(+)-K(+)-ATPase) activities; serum total and free thyroxine (tT4, fT4), total and free triiodothyronine (tT3, fT3), thyroid stimulating hormone (TSH) levels. Enlargement of thyroid with hypertrophic and hyperplastic changes, retarded TPO and 5'-DI but enhanced Na(+)-K(+)-ATPase activities, augmented serum total and free T4 and TSH but decreased total and free T3 levels and low T3/T4 ratio (T3:T4) were observed in the treated groups. All these findings indicate development of goitrogenesis upon exposure to excessive dietary calcium. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Prevention and treatment of glucocorticoid-induced osteoporosis: a comparison of calcitriol, vitamin D plus calcium, and alendronate plus calcium.

    PubMed

    Sambrook, Philip N; Kotowicz, Mark; Nash, Peter; Styles, Colin B; Naganathan, Vasi; Henderson-Briffa, Kathy N; Eisman, John A; Nicholson, Geoff C

    2003-05-01

    High-dose corticosteroids, used for many medical conditions, are associated with rapid bone loss from sites such as the vertebrae, and compression fractures can be observed within months. Recent trials suggest treatment with bisphosphonates or active vitamin D analogs can reduce bone loss and the risk of fracture associated with glucocorticoids, but few studies have directly compared such agents. We conducted a randomized, multicenter, open-label trial to compare the efficacy of alendronate, calcitriol, and simple vitamin D in prevention and treatment of glucocorticoid-induced bone loss. A total of 195 subjects (134 females and 61 males) commencing or already taking glucocorticoids were randomized to one of three groups: calcitriol, 0.5 to 0.75 microg/day; simple vitamin D (ergocalciferol, 30,000 IU weekly) plus calcium carbonate (600 mg daily); or alendronate, 10 mg/day plus calcium carbonate (600 mg daily). Over 2 years, mean lumbar bone mineral density change was +5.9% with alendronate, -0.5% with ergocalciferol, and -0.7% with calcitriol (p < 0.001). At the femoral neck, there was no significant difference in bone mineral density change between the treatments over 2 years: alendronate (+0.9%), ergocalciferol (-3.2%), and calcitriol (-2.2%). Lumbar bone loss varied according to whether patients were starting or receiving chronic glucocorticoids, and there was a significant treatment x prior glucocorticoid use interaction effect. Six of 66 calcitriol subjects, 1 of 61 ergocalciferol subjects, and 0 of 64 alendronate subjects sustained new vertebral fractures. These data do not suggest any difference between simple vitamin D and calcitriol but do show that alendronate was superior to either treatment for glucocorticoid induced bone loss.

  11. Visualization of Calcium Dynamics in Kidney Proximal Tubules

    PubMed Central

    Szebényi, Kornélia; Füredi, András; Kolacsek, Orsolya; Csohány, Rózsa; Prókai, Ágnes; Kis-Petik, Katalin; Szabó, Attila; Bősze, Zsuzsanna; Bender, Balázs; Tóvári, József; Enyedi, Ágnes; Orbán, Tamás I.

    2015-01-01

    Intrarenal changes in cytoplasmic calcium levels have a key role in determining pathologic and pharmacologic responses in major kidney diseases. However, cell-specific delivery of calcium-sensitive probes in vivo remains problematic. We generated a transgenic rat stably expressing the green fluorescent protein-calmodulin–based genetically encoded calcium indicator (GCaMP2) predominantly in the kidney proximal tubules. The transposon-based method used allowed the generation of homozygous transgenic rats containing one copy of the transgene per allele with a defined insertion pattern, without genetic or phenotypic alterations. We applied in vitro confocal and in vivo two-photon microscopy to examine basal calcium levels and ligand- and drug-induced alterations in these levels in proximal tubular epithelial cells. Notably, renal ischemia induced a transient increase in cellular calcium, and reperfusion resulted in a secondary calcium load, which was significantly decreased by systemic administration of specific blockers of the angiotensin receptor and the Na-Ca exchanger. The parallel examination of in vivo cellular calcium dynamics and renal circulation by fluorescent probes opens new possibilities for physiologic and pharmacologic investigations. PMID:25788535

  12. One nuclear calcium transient induced by a single burst of action potentials represents the minimum signal strength in activity-dependent transcription in hippocampal neurons.

    PubMed

    Yu, Yan; Oberlaender, Kristin; Bengtson, C Peter; Bading, Hilmar

    2017-07-01

    Neurons undergo dramatic changes in their gene expression profiles in response to synaptic stimulation. The coupling of neuronal excitation to gene transcription is well studied and is mediated by signaling pathways activated by cytoplasmic and nuclear calcium transients. Despite this, the minimum synaptic activity required to induce gene expression remains unknown. To address this, we used cultured hippocampal neurons and cellular compartment analysis of temporal activity by fluorescence in situ hybridization (catFISH) that allows detection of nascent transcripts in the cell nucleus. We found that a single burst of action potentials, consisting of 24.4±5.1 action potentials during a 6.7±1.9s depolarization of 19.5±2.0mV causing a 9.3±0.9s somatic calcium transient, is sufficient to activate transcription of the immediate early gene arc (also known as Arg3.1). The total arc mRNA yield produced after a single burst-induced nuclear calcium transient was very small and, compared to unstimulated control neurons, did not lead to a significant increase in arc mRNA levels measured using quantitative reverse transcriptase PCR (qRT-PCR) of cell lysates. Significantly increased arc mRNA levels became detectable in hippocampal neurons that had undergone 5-8 consecutive burst-induced nuclear calcium transients at 0.05-0.15Hz. These results indicate that a single burst-induced nuclear calcium transient can activate gene expression and that transcription is rapidly shut off after synaptic stimulation has ceased. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Platelet factor 4/CXCL4 induces phagocytosis and the generation of reactive oxygen metabolites in mononuclear phagocytes independently of Gi protein activation or intracellular calcium transients.

    PubMed

    Pervushina, Olga; Scheuerer, Barbara; Reiling, Norbert; Behnke, Lars; Schröder, Jens-M; Kasper, Brigitte; Brandt, Ernst; Bulfone-Paus, Silvia; Petersen, Frank

    2004-08-01

    Platelet factor 4 (PF-4), a platelet-derived CXC chemokine, is known to prevent human monocytes from apoptosis and to promote differentiation of these cells into HLA-DR(-) macrophages. In this study, we investigated the role of PF-4 in the control of acute monocyte proinflammatory responses involved in the direct combat of microbial invaders. We show that PF-4 increases monocyte phagocytosis and provokes a strong formation of oxygen radicals but lacks a chemotactic activity in these cells. Compared with FMLP, PF-4-induced oxidative burst was later in its onset but was remarkably longer in its duration (lasting for up to 60 min). Furthermore, in PF-4-prestimulated cells, FMLP- as well as RANTES-induced burst responses became synergistically enhanced. As we could show, PF-4-mediated oxidative burst in monocytes does not involve Gi proteins, elevation of intracellular free calcium concentrations, or binding to CXCR3B, a novel PF-4 receptor recently discovered on endothelial cells. Moreover, we found that PF-4 acts on macrophages in a dual manner. On the one hand, very similar to GM-CSF or M-CSF, PF-4 treatment of monocytes generates macrophages with a high capacity for unspecific phagocytosis. On the other hand, short term priming of GM-CSF-induced human macrophages with PF-4 substantially increases their capability for particle ingestion and oxidative burst. A comparable effect was also observed in murine bone marrow-derived macrophages, indicating cross-reactivity of human PF-4 between both species. Taken together, PF-4 may play a crucial role in the induction and maintenance of an unspecific immune response.

  14. Energetics of discrete selectivity bands and mutation-induced transitions in the calcium-sodium ion channels family

    NASA Astrophysics Data System (ADS)

    Kaufman, I.; Luchinsky, D. G.; Tindjong, R.; McClintock, P. V. E.; Eisenberg, R. S.

    2013-11-01

    We use Brownian dynamics (BD) simulations to study the ionic conduction and valence selectivity of a generic electrostatic model of a biological ion channel as functions of the fixed charge Qf at its selectivity filter. We are thus able to reconcile the discrete calcium conduction bands recently revealed in our BD simulations, M0 (Qf=1e), M1 (3e), M2 (5e), with a set of sodium conduction bands L0 (0.5e), L1 (1.5e), thereby obtaining a completed pattern of conduction and selectivity bands vs Qf for the sodium-calcium channels family. An increase of Qf leads to an increase of calcium selectivity: L0 (sodium-selective, nonblocking channel) → M0 (nonselective channel) → L1 (sodium-selective channel with divalent block) → M1 (calcium-selective channel exhibiting the anomalous mole fraction effect). We create a consistent identification scheme where the L0 band is putatively identified with the eukaryotic sodium channel The scheme created is able to account for the experimentally observed mutation-induced transformations between nonselective channels, sodium-selective channels, and calcium-selective channels, which we interpret as transitions between different rows of the identification table. By considering the potential energy changes during permeation, we show explicitly that the multi-ion conduction bands of calcium and sodium channels arise as the result of resonant barrierless conduction. The pattern of periodic conduction bands is explained on the basis of sequential neutralization taking account of self-energy, as Qf(z,i)=ze(1/2+i), where i is the order of the band and z is the valence of the ion. Our results confirm the crucial influence of electrostatic interactions on conduction and on the Ca2+/Na+ valence selectivity of calcium and sodium ion channels. The model and results could be also applicable to biomimetic nanopores with charged walls.

  15. Why Calcium? How Calcium Became the Best Communicator*

    PubMed Central

    Carafoli, Ernesto; Krebs, Joachim

    2016-01-01

    Calcium carries messages to virtually all important functions of cells. Although it was already active in unicellular organisms, its role became universally important after the transition to multicellular life. In this Minireview, we explore how calcium ended up in this privileged position. Most likely its unique coordination chemistry was a decisive factor as it makes its binding by complex molecules particularly easy even in the presence of large excesses of other cations, e.g. magnesium. Its free concentration within cells can thus be maintained at the very low levels demanded by the signaling function. A large cadre of proteins has evolved to bind or transport calcium. They all contribute to buffer it within cells, but a number of them also decode its message for the benefit of the target. The most important of these “calcium sensors” are the EF-hand proteins. Calcium is an ambivalent messenger. Although essential to the correct functioning of cell processes, if not carefully controlled spatially and temporally within cells, it generates variously severe cell dysfunctions, and even cell death. PMID:27462077

  16. Organic Selenium Alleviated the Formation of Ethylene Glycol-Induced Calcium Oxalate Renal Calculi by Improving Osteopontin Expression and Antioxidant Capability in Dogs.

    PubMed

    Liu, Yongwang; Xu, Haibin; Zhong, Wenting; Shen, Qingpeng; Zhuang, Tenghan; Huang, Kehe

    2015-12-01

    Twenty one-year-old local male dogs were randomly assigned into four groups (five dogs per group). The control and the ethylene glycol (EG) groups were fed basal diets without and with EG, and the EG+sodium selenite (EG+SS) and EG+selenium yeast (EG+SY) groups were fed basal diets with EG containing SS and SY, respectively. Blood, urine, and renal samples were taken after 18 weeks of feeding. The results showed that compared with the control group, the serum calcium levels and antioxidase activities significantly decreased in the EG group. Serum creatinine, urea nitrogen, and malondialdehyde (MDA) levels and urine calcium and oxalate levels significantly increased. Calcium oxalate crystal deposition and osteopontin (OPN) messenger RNA and protein expression in the renal tissues significantly increased. These changes above in the EG group were reversed within limits by adding selenium in the diets (both EG+SS and EG+SY groups). Further, compared with the EG+SS group, the EG+SY group showed better effects in decreasing the formation of EG-induced calcium oxalate renal calculi and OPN expression and improving antioxidant capability in dogs. It indicates that organic selenium has the potential value to alleviate the formation of EG-induced calcium oxalate renal calculi.

  17. Rapid Electrical Stimulation Increased Cardiac Apoptosis Through Disturbance of Calcium Homeostasis and Mitochondrial Dysfunction in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes.

    PubMed

    Geng, Le; Wang, Zidun; Cui, Chang; Zhu, Yue; Shi, Jiaojiao; Wang, Jiaxian; Chen, Minglong

    2018-06-15

    Heart failure induced by tachycardia, the most common arrhythmia, is frequently observed in clinical practice. This study was designed to investigate the underlying mechanisms. Rapid electrical stimulation (RES) at a frequency of 3 Hz was applied on human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) for 7 days, with 8 h/day and 24 h/day set to represent short-term and long-term tachycardia, respectively. Age-matched hiPSC-CMs without electrical stimulation or with slow electrical stimulation (1 Hz) were set as no electrical stimulation (NES) control or low-frequency electrical stimulation (LES) control. Following stimulation, JC-1 staining flow cytometry analysis was performed to examine mitochondrial conditions. Apoptosis in hiPSC-CMs was evaluated using Hoechst staining and Annexin V/propidium iodide (AV/PI) staining flow cytometry analysis. Calcium transients and L-type calcium currents were recorded to evaluate calcium homeostasis. Western blotting and qPCR were performed to evaluate the protein and mRNA expression levels of apoptosis-related genes and calcium homeostasis-regulated genes. Compared to the controls, hiPSC-CMs following RES presented mitochondrial dysfunction and an increased apoptotic percentage. Amplitudes of calcium transients and L-type calcium currents were significantly decreased in hiPSC-CMs with RES. Molecular analysis demonstrated upregulated expression of Caspase3 and increased Bax/Bcl-2 ratio. Genes related to calcium re-sequence were downregulated, while phosphorylated Ca2+/calmodulin-dependent protein kinase II (CaMKII) was significantly upregulated following RES. There was no significant difference between the NES control and LES control groups in these aspects. Inhibition of CaMKII with 1 µM KN93 partly reversed these adverse effects of RES. RES on hiPSC-CMs disturbed calcium homeostasis, which led to mitochondrial stress, promoted cell apoptosis and caused electrophysiological remodeling in a time

  18. Calcium Activates Nedd4 E3 Ubiquitin Ligases by Releasing the C2 Domain-mediated Auto-inhibition*

    PubMed Central

    Wang, Jian; Peng, Qisheng; Lin, Qiong; Childress, Chandra; Carey, David; Yang, Wannian

    2010-01-01

    Nedd4 E3 ligases are members of the HECT E3 ubiquitin ligase family and regulate ubiquitination-mediated protein degradation. In this report, we demonstrate that calcium releases the C2 domain-mediated auto-inhibition in both Nedd4-1 and Nedd4-2. Calcium disrupts binding of the C2 domain to the HECT domain. Consistent with this, calcium activates the E3 ubiquitin ligase activity of Nedd4. Elevation of intracellular calcium by ionomycin treatment, or activation of acetylcholine receptor or epidermal growth factor receptor by carbachol or epidermal growth factor stimulation induced activation of endogenous Nedd4 in vivo evaluated by assays of either Nedd4 E3 ligase activity or ubiquitination of Nedd4 substrate ENaC-β. The activation effect of calcium on Nedd4 E3 ligase activity was dramatically enhanced by a membrane-rich fraction, suggesting that calcium-mediated membrane translocation through the C2 domain might be an activation mechanism of Nedd4 in vivo. Our studies have revealed an activation mechanism of Nedd4 E3 ubiquitin ligases and established a connection of intracellular calcium signaling to regulation of protein ubiquitination. PMID:20172859

  19. Transforming growth factor-beta1 accelerates resorption of a calcium carbonate biomaterial in periodontal defects.

    PubMed

    Koo, Ki-Tae; Susin, Cristiano; Wikesjö, Ulf M E; Choi, Seong-Ho; Kim, Chong-Kwan

    2007-04-01

    In a previous study, recombinant human transforming growth factor-beta1 (rhTGF-beta(1)) in a calcium carbonate carrier was implanted into critical-size, supraalveolar periodontal defects under conditions for guided tissue regeneration (GTR) to study whether rhTGF-beta(1) would enhance or accelerate periodontal regeneration. The results showed minimal benefits of rhTGF-beta(1), and a clear account for this could not be offered. One potential cause may be that the rhTGF-beta(1) formulation was biologically inactive. Several growth or differentiation factors have been suggested to accelerate degradation of biomaterials used as carriers. The objective of this study was to evaluate possible activity of rhTGF-beta(1) on biodegradation of the calcium carbonate carrier. rhTGF-beta(1) in a putty-formulated particulate calcium carbonate carrier was implanted into critical-size, supraalveolar periodontal defects under conditions for GTR in five beagle dogs. Contralateral defects received the calcium carbonate carrier combined with GTR without rhTGF-beta(1) (control). The animals were euthanized at week 4 post-surgery and block biopsies of the defect sites were collected for histologic and histometric analysis. Radiographs were obtained at defect creation and weeks 2 and 4 after defect creation. No statistically significant differences were observed in new bone formation (bone height and area) among the treatments. However, total residual carrier was significantly reduced in sites receiving rhTGF-beta(1) compared to control (P = 0.04). Similarly, carrier density was considerably reduced in sites receiving rhTGF-beta(1) compared to control; the difference was borderline statistically significant (P = 0.06). Within the limitations of the study, it may be concluded that rhTGF-beta(1) accelerates biodegradation of a particulate calcium carbonate biomaterial, indicating a biologic activity of the rhTGF-beta(1) formulation apparently not encompassing enhanced or accelerated

  20. 3D plotting of growth factor loaded calcium phosphate cement scaffolds.

    PubMed

    Akkineni, Ashwini Rahul; Luo, Yongxiang; Schumacher, Matthias; Nies, Berthold; Lode, Anja; Gelinsky, Michael

    2015-11-01

    Additive manufacturing allows to widely control the geometrical features of implants. Recently, we described the fabrication of calcium phosphate cement (CPC) scaffolds by 3D plotting of a storable CPC paste based on water-immiscible carrier liquid. Plotting and hardening is conducted under mild conditions allowing the (precise and local) integration of biological components. In this study, we have developed a procedure for efficient loading of growth factors in the CPC scaffolds during plotting and demonstrated the feasibility of this approach. Bovine serum albumin (BSA) or vascular endothelial growth factor (VEGF), used as model proteins, were encapsulated in chitosan/dextran sulphate microparticles which could be easily mixed into the CPC paste in freeze-dried state. In order to prevent leaching of the proteins during cement setting, usually carried out by immersion in aqueous solutions, the plotted scaffolds were aged in water-saturated atmosphere (humidity). Setting in humidity avoided early loss of loaded proteins but provided sufficient amount of water to allow cement setting, as indicated by XRD analysis and mechanical testing in comparison to scaffolds set in water. Moreover, humidity-set scaffolds were characterised by altered, even improved properties: no swelling or crack formation was observed and accordingly, surface topography, total porosity and compressive modulus of the humidity-set scaffolds differed from those of the water-set counterparts. Direct cultivation of mesenchymal stem cells on the humidity-set scaffolds over 21days revealed their cytocompatibility. Maintenance of the bioactivity of VEGF during the fabrication procedure was proven in indirect and direct culture experiments with endothelial cells. Additive manufacturing techniques allow the fabrication of implants with defined architecture (inner pore structure and outer shape). Especially printing technologies conducted under mild conditions allow additionally the (spatially controlled

  1. Hyperglycemia Suppresses Calcium Phosphate-Induced Aneurysm Formation Through Inhibition of Macrophage Activation.

    PubMed

    Tanaka, Teruyoshi; Takei, Yuichiro; Yamanouchi, Dai

    2016-03-28

    The aim of this study was to elucidate aspects of diabetes mellitus-induced suppression of aneurysm. We hypothesized that high glucose suppresses aneurysm by inhibiting macrophage activation via activation of Nr1h2 (also known as liver X receptor β), recently characterized as a glucose-sensing nuclear receptor. Calcium phosphate (CaPO4)-induced aneurysm formation was significantly suppressed in the arterial wall in type 1 and 2 diabetic mice. A murine macrophage cell line, RAW264.7, was treated with tumor necrosis factor α (TNF-α) plus CaPO4 and showed a significant increase in matrix metalloproteinase 9 (Mmp9) mRNA and secreted protein expression compared with TNF-α alone. Elevated Mmp9 expression was significantly suppressed by hyperglycemic conditions (15.5 mmol/L glucose) compared with normoglycemic conditions (5.5 mmol/L glucose) or normoglycemic conditions with high osmotic pressure (5.5 mmol/L glucose +10.0 mmol/L mannitol). Nr1h2 mRNA and protein expression were suppressed by treatment with TNF-α plus CaPO4 but were restored by hyperglycemic conditions. Activation of Nr1h2 by the antagonist GW3965 during stimulation with TNF-α plus CaPO4 mimicked hyperglycemic conditions and inhibited Mmp9 upregulation, whereas the deactivation of Nr1h2 by small interfering RNA (siRNA) under hyperglycemic conditions canceled the suppressive effect and restored Mmp9 expression induced by TNF-α plus CaPO4. Moreover, Nr1h2 activation with GW3965 significantly suppressed CaPO4-induced aneurysm in mice compared with vehicle-injected control mice. Our results show that hyperglycemia suppresses macrophage activation and aneurysmal degeneration through the activation of Nr1h2. Although further validation of the underlying pathway is necessary, targeting Nr1h2 is a potential therapeutic approach to treating aneurysm. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  2. Hypochlorhydria-induced calcium malabsorption does not affect fracture healing but increases post-traumatic bone loss in the intact skeleton.

    PubMed

    Haffner-Luntzer, Melanie; Heilmann, Aline; Heidler, Verena; Liedert, Astrid; Schinke, Thorsten; Amling, Michael; Yorgan, Timur Alexander; Vom Scheidt, Annika; Ignatius, Anita

    2016-11-01

    Efficient calcium absorption is essential for skeletal health. Patients with impaired gastric acidification display low bone mass and increased fracture risk because calcium absorption is dependent on gastric pH. We investigated fracture healing and post-traumatic bone turnover in mice deficient in Cckbr, encoding a gastrin receptor that affects acid secretion by parietal cells. Cckbr-/- mice display hypochlorhydria, calcium malabsorption, and osteopenia. Cckbr-/- and wildtype (WT) mice received a femur osteotomy and were fed either a standard or calcium-enriched diet. Healed and intact bones were assessed by biomechanical testing, histomorphometry, micro-computed tomography, and quantitative backscattering. Parathyroid hormone (PTH) serum levels were determined by enzyme-linked immunosorbent assay. Fracture healing was unaffected in Cckbr-/- mice. However, Cckbr-/- mice displayed increased calcium mobilization from the intact skeleton during bone healing, confirmed by significantly elevated PTH levels and osteoclast numbers compared to WT mice. Calcium supplementation significantly reduced secondary hyperparathyroidism and bone resorption in the intact skeleton in both genotypes, but more efficiently in WT mice. Furthermore, calcium administration improved bone healing in WT mice, indicated by significantly increased mechanical properties and bone mineral density of the fracture callus, whereas it had no significant effect in Cckbr-/- mice. Therefore, under conditions of hypochlorhydria-induced calcium malabsorption, calcium, which is essential for callus mineralization, appears to be increasingly mobilized from the intact skeleton in favor of fracture healing. Calcium supplementation during fracture healing prevented systemic calcium mobilization, thereby maintaining bone mass and improving fracture healing in healthy individuals whereas the effect was limited by gastric hypochlorhydria. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J

  3. UCP1 deficiency causes brown fat respiratory chain depletion and sensitizes mitochondria to calcium overload-induced dysfunction

    PubMed Central

    Kazak, Lawrence; Chouchani, Edward T.; Stavrovskaya, Irina G.; Lu, Gina Z.; Jedrychowski, Mark P.; Egan, Daniel F.; Kumari, Manju; Kong, Xingxing; Erickson, Brian K.; Szpyt, John; Rosen, Evan D.; Murphy, Michael P.; Kristal, Bruce S.; Gygi, Steven P.; Spiegelman, Bruce M.

    2017-01-01

    Brown adipose tissue (BAT) mitochondria exhibit high oxidative capacity and abundant expression of both electron transport chain components and uncoupling protein 1 (UCP1). UCP1 dissipates the mitochondrial proton motive force (Δp) generated by the respiratory chain and increases thermogenesis. Here we find that in mice genetically lacking UCP1, cold-induced activation of metabolism triggers innate immune signaling and markers of cell death in BAT. Moreover, global proteomic analysis reveals that this cascade induced by UCP1 deletion is associated with a dramatic reduction in electron transport chain abundance. UCP1-deficient BAT mitochondria exhibit reduced mitochondrial calcium buffering capacity and are highly sensitive to mitochondrial permeability transition induced by reactive oxygen species (ROS) and calcium overload. This dysfunction depends on ROS production by reverse electron transport through mitochondrial complex I, and can be rescued by inhibition of electron transfer through complex I or pharmacologic depletion of ROS levels. Our findings indicate that the interscapular BAT of Ucp1 knockout mice exhibits mitochondrial disruptions that extend well beyond the deletion of UCP1 itself. This finding should be carefully considered when using this mouse model to examine the role of UCP1 in physiology. PMID:28630339

  4. UCP1 deficiency causes brown fat respiratory chain depletion and sensitizes mitochondria to calcium overload-induced dysfunction.

    PubMed

    Kazak, Lawrence; Chouchani, Edward T; Stavrovskaya, Irina G; Lu, Gina Z; Jedrychowski, Mark P; Egan, Daniel F; Kumari, Manju; Kong, Xingxing; Erickson, Brian K; Szpyt, John; Rosen, Evan D; Murphy, Michael P; Kristal, Bruce S; Gygi, Steven P; Spiegelman, Bruce M

    2017-07-25

    Brown adipose tissue (BAT) mitochondria exhibit high oxidative capacity and abundant expression of both electron transport chain components and uncoupling protein 1 (UCP1). UCP1 dissipates the mitochondrial proton motive force (Δp) generated by the respiratory chain and increases thermogenesis. Here we find that in mice genetically lacking UCP1, cold-induced activation of metabolism triggers innate immune signaling and markers of cell death in BAT. Moreover, global proteomic analysis reveals that this cascade induced by UCP1 deletion is associated with a dramatic reduction in electron transport chain abundance. UCP1-deficient BAT mitochondria exhibit reduced mitochondrial calcium buffering capacity and are highly sensitive to mitochondrial permeability transition induced by reactive oxygen species (ROS) and calcium overload. This dysfunction depends on ROS production by reverse electron transport through mitochondrial complex I, and can be rescued by inhibition of electron transfer through complex I or pharmacologic depletion of ROS levels. Our findings indicate that the interscapular BAT of Ucp1 knockout mice exhibits mitochondrial disruptions that extend well beyond the deletion of UCP1 itself. This finding should be carefully considered when using this mouse model to examine the role of UCP1 in physiology.

  5. Chiral acidic amino acids induce chiral hierarchical structure in calcium carbonate

    PubMed Central

    Jiang, Wenge; Pacella, Michael S.; Athanasiadou, Dimitra; Nelea, Valentin; Vali, Hojatollah; Hazen, Robert M.; Gray, Jeffrey J.; McKee, Marc D.

    2017-01-01

    Chirality is ubiquitous in biology, including in biomineralization, where it is found in many hardened structures of invertebrate marine and terrestrial organisms (for example, spiralling gastropod shells). Here we show that chiral, hierarchically organized architectures for calcium carbonate (vaterite) can be controlled simply by adding chiral acidic amino acids (Asp and Glu). Chiral, vaterite toroidal suprastructure having a ‘right-handed' (counterclockwise) spiralling morphology is induced by L-enantiomers of Asp and Glu, whereas ‘left-handed' (clockwise) morphology is induced by D-enantiomers, and sequentially switching between amino-acid enantiomers causes a switch in chirality. Nanoparticle tilting after binding of chiral amino acids is proposed as a chiral growth mechanism, where a ‘mother' subunit nanoparticle spawns a slightly tilted, consequential ‘daughter' nanoparticle, which by amplification over various length scales creates oriented mineral platelets and chiral vaterite suprastructures. These findings suggest a molecular mechanism for how biomineralization-related enantiomers might exert hierarchical control to form extended chiral suprastructures. PMID:28406143

  6. Signaling complexes of voltage-gated calcium channels

    PubMed Central

    Turner, Ray W; Anderson, Dustin

    2011-01-01

    Voltage-gated calcium channels are key mediators of depolarization induced calcium entry into electrically excitable cells. There is increasing evidence that voltage-gated calcium channels, like many other types of ionic channels, do not operate in isolation, but instead form complexes with signaling molecules, G protein coupled receptors, and other types of ion channels. Furthermore, there appears to be bidirectional signaling within these protein complexes, thus allowing not only for efficient translation of calcium signals into cellular responses, but also for tight control of calcium entry per se. In this review, we will focus predominantly on signaling complexes between G protein-coupled receptors and high voltage activated calcium channels, and on complexes of voltage-gated calcium channels and members of the potassium channel superfamily. PMID:21832880

  7. Lead-induced ER calcium release and inhibitory effects of methionine choline in cultured rat hippocampal neurons.

    PubMed

    Fan, Guangqin; Zhou, Fankun; Feng, Chang; Wu, Fengyun; Ye, Weiwei; Wang, Chunhong; Lin, Fen; Yan, Ji; Li, Yanshu; Chen, Ying; Bi, Yongyi

    2013-02-01

    Lead, a ubiquitous neurotoxicant, can result in learning and memory dysfunction. Long term potentiation in the hippocampus, a potential neural substrate for learning and memory, is thought to be linked to calcium-triggered intracellular events. In this study, laser scanning confocal microscopy was used to examine the effects of Pb(2+) on intracellular and endoplasmic reticulum free calcium concentration ([Ca(2+)](i) and [Ca(2+)](ER)) in cultured neonatal rat hippocampal neurons and their possible antagonism by methionine choline; understanding these effects would help explain the lead-induced cognitive and learning dysfunction and explore efficient safety and relief strategies. The results showed that Pb(2+) increased [Ca(2+)](i) and decreased [Ca(2+)](ER) linearly in a time- and concentration-dependant manner, and Pb(2+) addition after the applying of a ryanodine receptor (RyR) antagonist and an inositol-1,4,5-triphosphate receptor (IP(3)R) antagonist did not increase [Ca(2+)](i). The addition of 10, 20, or 40 mmol/L methionine choline simultaneously with addition of 10 μmol/L Pb(2+) decreased [Ca(2+)](i) in Ca(2+)-free culture medium by 39.0%, 66.0%, and 61.6%, respectively, in a concentration-dependant manner in a certain dose range. Our results suggest that Pb(2+) induces ER calcium release to increase the resting [Ca(2+)](i); and methionine choline inhibit this increase in [Ca(2+)](i). Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Kokumi Substances, Enhancers of Basic Tastes, Induce Responses in Calcium-Sensing Receptor Expressing Taste Cells

    PubMed Central

    Maruyama, Yutaka; Yasuda, Reiko; Kuroda, Motonaka; Eto, Yuzuru

    2012-01-01

    Recently, we reported that calcium-sensing receptor (CaSR) is a receptor for kokumi substances, which enhance the intensities of salty, sweet and umami tastes. Furthermore, we found that several γ-glutamyl peptides, which are CaSR agonists, are kokumi substances. In this study, we elucidated the receptor cells for kokumi substances, and their physiological properties. For this purpose, we used Calcium Green-1 loaded mouse taste cells in lingual tissue slices and confocal microscopy. Kokumi substances, applied focally around taste pores, induced an increase in the intracellular Ca2+ concentration ([Ca2+]i) in a subset of taste cells. These responses were inhibited by pretreatment with the CaSR inhibitor, NPS2143. However, the kokumi substance-induced responses did not require extracellular Ca2+. CaSR-expressing taste cells are a different subset of cells from the T1R3-expressing umami or sweet taste receptor cells. These observations indicate that CaSR-expressing taste cells are the primary detectors of kokumi substances, and that they are an independent population from the influenced basic taste receptor cells, at least in the case of sweet and umami. PMID:22511946

  9. The Role of Calcium in Prevention and Treatment of Osteoporosis.

    ERIC Educational Resources Information Center

    Heaney, Robert P.

    1987-01-01

    Osteoporosis results from several factors. Calcium deficiency is only one, and high calcium intake will prevent only those cases in which calcium is the limiting factor. Calcium cannot reverse, but only arrest, bone loss. A high calcium intake for every member of the population is advocated. (Author/MT)

  10. [The anti-tumour effect of Wuxing soup and its mechanism in inducing apoptosis of tumour cells mediated by calcium].

    PubMed

    Mo, Fei; Hu, Jing-Ying; Gan, Yu; Zhao, Yang-Xing; Zhao, Xin-Tai

    2008-09-01

    To confirm the anti-cancer effect and mechanism of Wuxing soup. Inhibition of cellular growth under Wuxing soup treatment was observed by MTT; Apoptosis was detected by gel electrophoresis, transmission electron microscopy and FACS; The concentration of calcium was measured by fluorescence probe. After SGC-7901 cell being treated by Wuxing soup, it showed that: 1) Wuxing soup could specifically inhibit cancer cells proliferation in a time and dose dependent manner; 2) Typical apoptotic morphological changes and DNA ladder of SGC-7901 cells were observed; 3) calcium inhibitor Bapta AM could reduce the apoptotic rate and protect SGC-7901 cells in a dose dependent manner. Wuxing soup has an effective inhibition on cancer cells, and can induce SGC-7901 cells to apoptosis by calcium.

  11. Calcium movements and the cellular basis of gravitropism

    NASA Astrophysics Data System (ADS)

    Roux, S. J.; Biro, R. L.; Hale, C. C.

    An early gravity-transduction event in oat coleoptiles which precedes any noticeable bending is the accumulation of calcium on their prospective slower-growing side. Sub-cellular calcium localization studies indicate that the gravity-stimulated redistribution of calcium results in an increased concentration of calcium in the walls of responding cells. Since calcium can inhibit the extension growth of plant cell walls, this selective accumulation of calcium in walls may play a role in inducing the asymmetry of growth which characterizes gravitropism. The active transport of calcium from cells into walls is performed by a calcium-dependent ATPase localized in the plasma membrane. Evidence is presented in support of the hypothesis that this calcium pump is regulated by a feed-back mechanism which includes the participation of calmodulin.

  12. Sound Waves Induce Neural Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells via Ryanodine Receptor-Induced Calcium Release and Pyk2 Activation.

    PubMed

    Choi, Yura; Park, Jeong-Eun; Jeong, Jong Seob; Park, Jung-Keug; Kim, Jongpil; Jeon, Songhee

    2016-10-01

    Mesenchymal stem cells (MSCs) have shown considerable promise as an adaptable cell source for use in tissue engineering and other therapeutic applications. The aims of this study were to develop methods to test the hypothesis that human MSCs could be differentiated using sound wave stimulation alone and to find the underlying mechanism. Human bone marrow (hBM)-MSCs were stimulated with sound waves (1 kHz, 81 dB) for 7 days and the expression of neural markers were analyzed. Sound waves induced neural differentiation of hBM-MSC at 1 kHz and 81 dB but not at 1 kHz and 100 dB. To determine the signaling pathways involved in the neural differentiation of hBM-MSCs by sound wave stimulation, we examined the Pyk2 and CREB phosphorylation. Sound wave induced an increase in the phosphorylation of Pyk2 and CREB at 45 min and 90 min, respectively, in hBM-MSCs. To find out the upstream activator of Pyk2, we examined the intracellular calcium source that was released by sound wave stimulation. When we used ryanodine as a ryanodine receptor antagonist, sound wave-induced calcium release was suppressed. Moreover, pre-treatment with a Pyk2 inhibitor, PF431396, prevented the phosphorylation of Pyk2 and suppressed sound wave-induced neural differentiation in hBM-MSCs. These results suggest that specific sound wave stimulation could be used as a neural differentiation inducer of hBM-MSCs.

  13. Calcium Signaling and Meiotic Exit at Fertilization in Xenopus Egg

    PubMed Central

    Tokmakov, Alexander A.; Stefanov, Vasily E.; Iwasaki, Tetsushi; Sato, Ken-Ichi; Fukami, Yasuo

    2014-01-01

    Calcium is a universal messenger that mediates egg activation at fertilization in all sexually reproducing species studied. However, signaling pathways leading to calcium generation and the mechanisms of calcium-induced exit from meiotic arrest vary substantially among species. Here, we review the pathways of calcium signaling and the mechanisms of meiotic exit at fertilization in the eggs of the established developmental model, African clawed frog, Xenopus laevis. We also discuss calcium involvement in the early fertilization-induced events in Xenopus egg, such as membrane depolarization, the increase in intracellular pH, cortical granule exocytosis, cortical contraction, contraction wave, cortical rotation, reformation of the nuclear envelope, sperm chromatin decondensation and sister chromatid segregation. PMID:25322156

  14. The Marine Guanidine Alkaloid Crambescidin 816 Induces Calcium Influx and Cytotoxicity in Primary Cultures of Cortical Neurons through Glutamate Receptors.

    PubMed

    Mendez, Aida G; Juncal, Andrea Boente; Silva, Siguara B L; Thomas, Olivier P; Martín Vázquez, Víctor; Alfonso, Amparo; Vieytes, Mercedes R; Vale, Carmen; Botana, Luís M

    2017-07-19

    Crambescidin 816 is a guanidine alkaloid produced by the sponge Crambe crambe with known antitumoral activity. While the information describing the effects of this alkaloid in central neurons is scarce, Cramb816 is known to block voltage dependent calcium channels being selective for L-type channels. Moreover, Cramb816 reduced neuronal viability through an unknown mechanism. Here, we aimed to describe the toxic activity of Cramb816 in cortical neurons. Since calcium influx is considered the main mechanism responsible for neuronal cell death, the effects of Cramb816 in the cytosolic calcium concentration of cortical neurons were studied. The alkaloid decreased neuronal viability and induced a dose-dependent increase in cytosolic calcium that was also related to the presence of calcium in the extracellular media. The increase in calcium influx was age dependent, being higher in younger neurons. Moreover, this effect was prevented by glutamate receptor antagonists, which did not fully block the cytotoxic effect of Cramb816 after 24 h of treatment but completely prevented Cramb816 cytotoxicity after 10 min exposure. Therefore, the findings presented herein provide new insights into the cytotoxic effect of Cramb816 in cortical neurons.

  15. Calcium homeostasis and protein kinase/phosphatase balance participate in nicotine-induced memory improvement in passive avoidance task in mice.

    PubMed

    Michalak, Agnieszka; Biala, Grazyna

    2017-01-15

    Long-term potentiation (LTP) and long-term depression (LTD) depend on specific postsynaptic Ca 2+ /calmodulin concentration. LTP results from Ca 2+ influx through the activated NMDA receptors or voltage-gated calcium channels (VGCCs) and is linked with activation of protein kinases including mitogen-activated protein kinase (MAPK). Weaker synaptic stimulation, as a result of low Ca 2+ influx, leads to activation of Ca 2+ /calmodulin-dependent phosphatase (calcineurin - CaN) and triggers LTD. Interestingly, both memory formation and drug addiction share similar neuroplastic changes. Nicotine, which is one of the most common addictive drugs, manifests its memory effects through nicotinic acetylcholine receptors (nAChRs). Because nAChRs may also gate Ca 2+ , it is suggested that calcium signaling pathways are involved in nicotine-induced memory effects. Within the scope of the study was to evaluate the importance of calcium homeostasis and protein kinase/phosphatase balance in nicotine-induced short- and long-term memory effects. To assess memory function in mice passive avoidance test was used. The presented results confirm that acute nicotine (0.1mg/kg) improves short- and long-term memory. Pretreatment with L-type VGCC blockers (amlodipine, nicardipine verapamil) increased nicotine-induced memory improvement in the context of short- and long-term memory. Pretreatment with FK-506 (a potent CaN inhibitor) enhanced short- but not long-term memory effects of nicotine, while SL-327 (a selective MAPK/ERK kinase inhibitor) attenuated both nicotine-induced short- and long-term memory improvement. Acute nicotine enhances both types of memory via L-type VGCC blockade and via ERK1/2 activation. Only short- but not long-term memory enhancement induced by nicotine is dependent on CaN inhibition. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Dopamine Induces LTP Differentially in Apical and Basal Dendrites through BDNF and Voltage-Dependent Calcium Channels

    ERIC Educational Resources Information Center

    Navakkode, Sheeja; Sajikumar, Sreedharan; Korte, Martin; Soong, Tuck Wah

    2012-01-01

    The dopaminergic modulation of long-term potentiation (LTP) has been studied well, but the mechanism by which dopamine induces LTP (DA-LTP) in CA1 pyramidal neurons is unknown. Here, we report that DA-LTP in basal dendrites is dependent while in apical dendrites it is independent of activation of L-type voltage-gated calcium channels (VDCC).…

  17. POWER DENSITY, FIELD INTENSITY, AND CARRIER FREQUENCY DETERMINANTS OF RF-ENERGY-INDUCED CALCIUM-ION EFFLUX FROM BRAIN TISSUE

    EPA Science Inventory

    To explain a carrier frequency dependence reported for radiofrequency (RF)-induced calcium-ion efflux from brain tissue, a chick-brain hemisphere bathed in buffer solution is modeled as a sphere within the uniform field of the incident electromagnetic wave. Calculations on a sphe...

  18. Why Calcium? How Calcium Became the Best Communicator.

    PubMed

    Carafoli, Ernesto; Krebs, Joachim

    2016-09-30

    Calcium carries messages to virtually all important functions of cells. Although it was already active in unicellular organisms, its role became universally important after the transition to multicellular life. In this Minireview, we explore how calcium ended up in this privileged position. Most likely its unique coordination chemistry was a decisive factor as it makes its binding by complex molecules particularly easy even in the presence of large excesses of other cations, e.g. magnesium. Its free concentration within cells can thus be maintained at the very low levels demanded by the signaling function. A large cadre of proteins has evolved to bind or transport calcium. They all contribute to buffer it within cells, but a number of them also decode its message for the benefit of the target. The most important of these "calcium sensors" are the EF-hand proteins. Calcium is an ambivalent messenger. Although essential to the correct functioning of cell processes, if not carefully controlled spatially and temporally within cells, it generates variously severe cell dysfunctions, and even cell death. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. Decreased contraction induced by endothelium-derived contracting factor in prolonged treatment of rat renal artery with endoplasmic reticulum stress inducer.

    PubMed

    Ando, Makoto; Matsumoto, Takayuki; Taguchi, Kumiko; Kobayashi, Tsuneo

    2018-05-04

    Recent evidence suggests that endoplasmic reticulum (ER) stress is involved in the regulation of various physiological functions, including those of the vascular system. However, the relationship between ER stress and vascular function is poorly understood. The endothelial cells control the vascular tone by releasing endothelium-derived relaxing factors and contracting factors (EDCFs). We hypothesized that tunicamycin, an inducer of ER stress, modifies endothelium-dependent contraction and prostaglandins (PGs), a major class of EDCFs, induced contractions in the rat renal artery in rats. An organ-culture technique was used to purely investigate the effects of ER stress on the vascular tissue. We observed that tunicamycin treatment (20 μg/mL for 23 ± 1 h) did not affect acetylcholine (ACh)-induced relaxation and decreased EDCF-mediated contractions under nitric oxide synthase (NOS) inhibition induced by ACh, ATP, or A23187 (a calcium ionophore) in the renal arteries. Under NOS inhibition, U46619 (a thromboxane A 2 mimetic)- and beraprost (a prostacyclin analog)-induced contractions were also decreased in the renal arteries of the tunicamycin-treated group (vs. vehicle), while PGE 2 - and PGF 2α -induced contractions were similar between the groups. Tunicamycin treatment slightly enhanced the contractions induced by phenylephrine, an α 1 adrenoceptor ligand. Isotonic high-K + -induced contractions were similar between the vehicle- and tunicamycin-treated groups. Another ER stress inducer, thapsigargin (4 μmol/L for 23 ± 1 h), also caused substantial reduction of ACh-induced EDCF-mediated contraction (vs. vehicle-treated group). In the cultured renal arteries, tunicamycin and thapsigargin increased the expression of binding immunoglobulin protein (BiP), an ER stress marker. In conclusion, ER stress induction directly affects renal arterial function, especially in reducing EDCF-mediated contractions.

  20. Characterization of postsynaptic calcium signals in the pyramidal neurons of anterior cingulate cortex

    PubMed Central

    Li, Xu-Hui; Song, Qian; Chen, Tao; Zhuo, Min

    2017-01-01

    Calcium signaling is critical for synaptic transmission and plasticity. N-methyl-D-aspartic acid (NMDA) receptors play a key role in synaptic potentiation in the anterior cingulate cortex. Most previous studies of calcium signaling focus on hippocampal neurons, little is known about the activity-induced calcium signals in the anterior cingulate cortex. In the present study, we show that NMDA receptor-mediated postsynaptic calcium signals induced by different synaptic stimulation in anterior cingulate cortex pyramidal neurons. Single and multi-action potentials evoked significant suprathreshold Ca2+ increases in somas and spines. Both NMDA receptors and voltage-gated calcium channels contributed to this increase. Postsynaptic Ca2+signals were induced by puff-application of glutamate, and a NMDA receptor antagonist AP5 blocked these signals in both somas and spines. Finally, long-term potentiation inducing protocols triggered postsynaptic Ca2+ influx, and these influx were NMDA receptor dependent. Our results provide the first study of calcium signals in the anterior cingulate cortex and demonstrate that NMDA receptors play important roles in postsynaptic calcium signals in anterior cingulate cortex pyramidal neurons. PMID:28726541

  1. Calcium signaling in immune cells

    PubMed Central

    Vig, Monika; Kinet, Jean-Pierre

    2010-01-01

    Calcium acts as a second messenger in many cell types, including lymphocytes. Resting lymphocytes maintain a low concentration of Ca2+. However, engagement of antigen receptors induces calcium influx from the extracellular space by several routes. A chief mechanism of Ca2+ entry in lymphocytes is through store-operated calcium (SOC) channels. The identification of two important molecular components of SOC channels, CRACM1 (the pore-forming subunit) and STIM1 (the sensor of stored calcium), has allowed genetic and molecular manipulation of the SOC entry pathway. In this review, we highlight advances in the understanding of Ca2+ signaling in lymphocytes with special emphasis on SOC entry. We also discuss outstanding questions and probable future directions of the field. PMID:19088738

  2. Energetics of discrete selectivity bands and mutation-induced transitions in the calcium-sodium ion channels family.

    PubMed

    Kaufman, I; Luchinsky, D G; Tindjong, R; McClintock, P V E; Eisenberg, R S

    2013-11-01

    We use Brownian dynamics (BD) simulations to study the ionic conduction and valence selectivity of a generic electrostatic model of a biological ion channel as functions of the fixed charge Q(f) at its selectivity filter. We are thus able to reconcile the discrete calcium conduction bands recently revealed in our BD simulations, M0 (Q(f)=1e), M1 (3e), M2 (5e), with a set of sodium conduction bands L0 (0.5e), L1 (1.5e), thereby obtaining a completed pattern of conduction and selectivity bands vs Q(f) for the sodium-calcium channels family. An increase of Q(f) leads to an increase of calcium selectivity: L0 (sodium-selective, nonblocking channel) → M0 (nonselective channel) → L1 (sodium-selective channel with divalent block) → M1 (calcium-selective channel exhibiting the anomalous mole fraction effect). We create a consistent identification scheme where the L0 band is putatively identified with the eukaryotic sodium channel The scheme created is able to account for the experimentally observed mutation-induced transformations between nonselective channels, sodium-selective channels, and calcium-selective channels, which we interpret as transitions between different rows of the identification table. By considering the potential energy changes during permeation, we show explicitly that the multi-ion conduction bands of calcium and sodium channels arise as the result of resonant barrierless conduction. The pattern of periodic conduction bands is explained on the basis of sequential neutralization taking account of self-energy, as Q(f)(z,i)=ze(1/2+i), where i is the order of the band and z is the valence of the ion. Our results confirm the crucial influence of electrostatic interactions on conduction and on the Ca(2+)/Na(+) valence selectivity of calcium and sodium ion channels. The model and results could be also applicable to biomimetic nanopores with charged walls.

  3. Effect of mood stabilizing agents on agonist-induced calcium mobilization in human platelets.

    PubMed Central

    Kusumi, I; Koyama, T; Yamashita, I

    1994-01-01

    The effect of mood stabilizing agents such as lithium, carbamazepine, valproic acid and clonazepam on serotonin(5-HT)- or thrombin-induced intracellular calcium (Ca) mobilization was studied in the platelets of healthy subjects using the fluorescent Ca indicator fura-2. After incubating platelet-rich plasma with these drugs for one or four hours, there was no significant difference in either basal Ca2+ concentration or 5-HT-stimulated Ca response between each agent treatment and control. 5-HT- or thrombin-induced Ca mobilization was not altered by four weeks of lithium carbonate administration in healthy volunteers. These results indicate that these mood stabilizers fail to affect the agonist-stimulated intracellular Ca mobilizing pathway either in vitro or ex vivo in the platelets of healthy subjects. Images Fig. 1 PMID:8031747

  4. Micropore-induced capillarity enhances bone distribution in vivo in biphasic calcium phosphate scaffolds.

    PubMed

    Rustom, Laurence E; Boudou, Thomas; Lou, Siyu; Pignot-Paintrand, Isabelle; Nemke, Brett W; Lu, Yan; Markel, Mark D; Picart, Catherine; Wagoner Johnson, Amy J

    2016-10-15

    The increasing demand for bone repair solutions calls for the development of efficacious bone scaffolds. Biphasic calcium phosphate (BCP) scaffolds with both macropores and micropores (MP) have improved healing compared to those with macropores and no micropores (NMP), but the role of micropores is unclear. Here, we evaluate capillarity induced by micropores as a mechanism that can affect bone growth in vivo. Three groups of cylindrical scaffolds were implanted in pig mandibles for three weeks: MP were implanted either dry (MP-Dry), or after submersion in phosphate buffered saline, which fills pores with fluid and therefore suppresses micropore-induced capillarity (MP-Wet); NMP were implanted dry. The amount and distribution of bone in the scaffolds were quantified using micro-computed tomography. MP-Dry had a more homogeneous bone distribution than MP-Wet, although the average bone volume fraction, BVF‾, was not significantly different for these two groups (0.45±0.03 and 0.37±0.03, respectively). There was no significant difference in the radial bone distribution of NMP and MP-Wet, but the BVF‾, of NMP was significantly lower among the three groups (0.25±0.02). These results suggest that micropore-induced capillarity enhances bone regeneration by improving the homogeneity of bone distribution in BCP scaffolds. The explicit design and use of capillarity in bone scaffolds may lead to more effective treatments of large and complex bone defects. The increasing demand for bone repair calls for more efficacious bone scaffolds and calcium phosphate-based materials are considered suitable for this application. Macropores (>100μm) are necessary for bone ingrowth and vascularization. However, studies have shown that microporosity (<20μm) also enhances growth, but there is no consensus on the controlling mechanisms. In previous in vitro work, we suggested that micropore-induced capillarity had the potential to enhance bone growth in vivo. This work illustrates the

  5. L-Histidine sensing by calcium sensing receptor inhibits voltage-dependent calcium channel activity and insulin secretion in β-cells

    PubMed Central

    Parkash, Jai; Asotra, Kamlesh

    2011-01-01

    Aims Our goal was to test the hypothesis that the histidine-induced activation of calcium sensing receptor (CaR) can regulate calcium channel activity of L-type voltage dependent calcium channel (VDCC) due to increased spatial interaction between CaR and VDCC in β-cells and thus modulate glucose-induced insulin secretion. Main methods Rat insulinoma (RINr1046-38) insulin-producing β-cells were cultured in RPMI-1640 medium on 25 mm diameter glass coverslips in six-well culture plates in a 5% CO2 incubator at 37°C. The intracellular calcium concentration, [Ca2+]i, was determined by ratio fluorescence microscopy using Fura-2AM. The spatial interactions between CaR and L-type VDCC in β-cells were measured by immunofluorescence confocal microscopy using a Nikon C1 laser scanning confocal microscope. The insulin release was determined by enzyme-linked immunosorbent assay (ELISA). Key findings The additions of increasing concentrations of L-histidine along with 10 mM glucose resulted in 57% decrease in [Ca2+]i. The confocal fluorescence imaging data showed 5.59 to 8.62-fold increase in colocalization correlation coefficient between CaR and VDCC in β-cells exposed to L-histidine thereby indicating increased membrane delimited spatial interactions between these two membrane proteins. The insulin ELISA data showed 54% decrease in 1st phase of glucose-induced insulin secretion in β-cells exposed to increasing concentrations of L-histidine. Significance L-histidine-induced increased spatial interaction of CaR with VDCC can inhibit calcium channel activity of VDCC and consequently regulate glucose-induced insulin secretion by β-cells. The L-type VDCC could therefore be potential therapeutic target in diabetes. PMID:21219913

  6. Transforming Growth Factor-β1 Accelerates Resorption of a Calcium Carbonate Biomaterial in Periodontal Defects.

    PubMed

    Koo, Ki-Tae; Susin, Cristiano; Wikesjö, Ulf M E; Choi, Seong-Ho; Kim, Chong-Kwan

    2007-04-01

    In a previous study, recombinant human transforming growth factor-beta1 (rhTGF-β 1 ) in a calcium carbonate carrier was implanted into critical-size, supraalveolar periodontal defects under conditions for guided tissue regeneration (GTR) to study whether rhTGF-β 1 would enhance or accelerate periodontal regeneration. The results showed minimal benefits of rhTGF-β 1 , and a clear account for this could not be offered. One potential cause may be that the rhTGF-β 1 formulation was biologically inactive. Several growth or differentiation factors have been suggested to accelerate degradation of biomaterials used as carriers. The objective of this study was to evaluate possible activity of rhTGF-β 1 on biodegradation of the calcium carbonate carrier. rhTGF-β 1 in a putty-formulated particulate calcium carbonate carrier was implanted into critical-size, supraalveolar periodontal defects under conditions for GTR in five beagle dogs. Contralateral defects received the calcium carbonate carrier combined with GTR without rhTGF-β 1 (control). The animals were euthanized at week 4 post-surgery and block biopsies of the defect sites were collected for histologic and histometric analysis. Radiographs were obtained at defect creation and weeks 2 and 4 after defect creation. No statistically significant differences were observed in new bone formation (bone height and area) among the treatments. However, total residual carrier was significantly reduced in sites receiving rhTGF-β 1 compared to control (P = 0.04). Similarly, carrier density was considerably reduced in sites receiving rhTGF-β 1 compared to control; the difference was borderline statistically significant (P = 0.06). Within the limitations of the study, it may be concluded that rhTGF-β 1 accelerates biodegradation of a particulate calcium carbonate biomaterial, indicating a biologic activity of the rhTGF-β 1 formulation apparently not encompassing enhanced or accelerated periodontal regeneration. © 2007

  7. Pre-electroconvulsive shock administration of calcium channel blockers reduces retrograde amnesia induced by ECS.

    PubMed

    Sushma, M; Sudha, S; Guido, S

    2004-11-01

    Effect of pre-electroconvulsive shock (ECS) administration of calcium channel blockers (CCBs) like verapamil, diltiazem, nifedipine, nimodipine, flunarizine and cinnarizine on retrograde amnesia induced by ECS was examined using passive avoidance paradigm in rats. The groups (Gr 1-7) of adult, male Wistar rats received true ECS with CCBs (5mg/kg; i.p) or vehicle (10 ml/kg; ip) and other groups (Gr 8-14) received sham ECS with CCBs (5mg/kg; i.p) or vehicle (10 ml/kg; i.p). The anti-amnestic activity of CCBs were evaluated using the passive avoidance paradigm in rats. Results showed that, the baseline latencies for all the groups did not differ significantly. Rats receiving true ECS produced significantly lower latencies. There was increase in the post ECS step through latencies of the rats administered CCBs before ECS. Therefore, pre-ECS administration of calcium channel blockers might reduce retrograde amnesia produced by ECS without altering seizure duration.

  8. Analysis of calcium-induced conformational changes in calcium-binding allergens and quantitative determination of their IgE binding properties.

    PubMed

    Parody, Nuria; Fuertes, Miguel Angel; Alonso, Carlos; Pico de Coaña, Yago

    2013-01-01

    The polcalcin family is one of the most epidemiologically relevant families of calcium-binding allergens. Polcalcins are potent plant allergens that contain one or several EF-hand motifs and their allergenicity is primarily associated with the Ca(2+)-bound form of the protein. Conformation, stability, as well as IgE recognition of calcium-binding allergens greatly depend on the presence of protein-bound calcium ions. We describe a protocol that uses three techniques (SDS-PAGE, circular dichroism spectroscopy, and ELISA) to describe the effects that calcium has on the structural changes in an allergen and its IgE binding properties.

  9. Effect of calcium, bicarbonate, and albumin on capacitation-related events in equine sperm.

    PubMed

    Macías-García, B; González-Fernández, L; Loux, S C; Rocha, A M; Guimarães, T; Peña, F J; Varner, D D; Hinrichs, K

    2015-01-01

    Repeatable methods for IVF have not been established in the horse, reflecting the failure of standard capacitating media to induce changes required for fertilization capacity in equine sperm. One important step in capacitation is membrane cholesterol efflux, which in other species is triggered by cholesterol oxidation and is typically enhanced using albumin as a sterol acceptor. We incubated equine sperm in the presence of calcium, BSA, and bicarbonate, alone or in combination. Bicarbonate induced an increase in reactive oxygen species (ROS) that was abolished by the addition of calcium or BSA. Bicarbonate induced protein tyrosine phosphorylation (PY), even in the presence of calcium or BSA. Incubation at high pH enhanced PY but did not increase ROS production. Notably, no combination of these factors was associated with significant cholesterol efflux, as assessed by fluorescent quantitative cholesterol assay and confirmed by filipin staining. By contrast, sperm treated with methyl-β-cyclodextrin showed a significant reduction in cholesterol levels, but no significant increase in PY or ROS. Presence of BSA increased sperm binding to bovine zonae pellucidae in all three stallions. These results show that presence of serum albumin is not associated with a reduction in membrane cholesterol levels in equine sperm, highlighting the failure of equine sperm to exhibit core capacitation-related changes in a standard capacitating medium. These data indicate an atypical relationship among cholesterol efflux, ROS production, and PY in equine sperm. Our findings may help to elucidate factors affecting failure of equine IVF under standard conditions. © 2015 Society for Reproduction and Fertility.

  10. Increased calcium deposits and decreased Ca2+ -ATPase in erythrocytes of ascitic broiler chickens.

    PubMed

    Li, Kai; Zhao, Lihong; Geng, Guangrui; Ma, Liqin; Dong, Shishan; Xu, Tong; Wang, Jianlin; Wang, Huiyu; Tian, Yong; Qiao, Jian

    2011-06-01

    The decrease of erythrocyte deformability may be one of the predisposing factors for pulmonary hypertension and ascites in broiler chickens. In mammals, the cytoplasmic calcium is a major regulator of erythrocyte deformability. In this study, the erythrocyte deformability was measured, and the precise locations of Ca2+ and Ca2+ -ATPase in the erythrocytes were investigated in chickens with ascites syndrome induced by low ambient temperature. The results showed that ascitic broilers had higher filtration index of erythrocyte compared with control groups, indicating a decrease in erythrocyte deformability in ascitic broilers. The more calcium deposits were observed in the erythrocytes of ascitic broilers compared with those of the age-matched control birds. The Ca2+ -ATPase reactive grains were significantly decreased on the erythrocyte membranes of ascitic broilers. Our data suggest that accumulation of intracellular calcium and inhibition of Ca2+ -ATPase might be important factors for the reduced deformability of the erythrocytes of ascitic broilers. Copyright © 2010 Elsevier Ltd. All rights reserved.

  11. Calcium Signaling in Taste Cells

    PubMed Central

    Medler, Kathryn F.

    2014-01-01

    The sense of taste is a common ability shared by all organisms and is used to detect nutrients as well as potentially harmful compounds. Thus taste is critical to survival. Despite its importance, surprisingly little is known about the mechanisms generating and regulating responses to taste stimuli. All taste responses depend on calcium signals to generate appropriate responses which are relayed to the brain. Some taste cells have conventional synapses and rely on calcium influx through voltage-gated calcium channels. Other taste cells lack these synapses and depend on calcium release to formulate an output signal through a hemichannel. Beyond establishing these characteristics, few studies have focused on understanding how these calcium signals are formed. We identified multiple calcium clearance mechanisms that regulate calcium levels in taste cells as well as a calcium influx that contributes to maintaining appropriate calcium homeostasis in these cells. Multiple factors regulate the evoked taste signals with varying roles in different cell populations. Clearly, calcium signaling is a dynamic process in taste cells and is more complex than has previously been appreciated. PMID:25450977

  12. Inhibition of polar calcium movement and gravitropism in roots treated with auxin-transport inhibitors

    NASA Technical Reports Server (NTRS)

    Lee, J. S.; Mulkey, T. J.; Evans, M. L.

    1984-01-01

    Primary roots of maize (Zea mays L.) and pea (Pisum sativum L.) exhibit strong positive gravitropism. In both species, gravistimulation induces polar movement of calcium across the root tip from the upper side to the lower side. Roots of onion (Allium cepa L.) are not responsive to gravity and gravistimulation induces little or no polar movement of calcium across the root tip. Treatment of maize or pea roots with inhibitors of auxin transport (morphactin, naphthylphthalamic acid, 2,3,5-triiodobenzoic acid) prevents both gravitropism and gravity-induced polar movement of calcium across the root tip. The results indicate that calcium movement and auxin movement are closely linked in roots and that gravity-induced redistribution of calcium across the root cap may play an important role in the development of gravitropic curvature.

  13. Calcium Input Frequency, Duration and Amplitude Differentially Modulate the Relative Activation of Calcineurin and CaMKII

    PubMed Central

    Li, Lu; Stefan, Melanie I.; Le Novère, Nicolas

    2012-01-01

    NMDA receptor dependent long-term potentiation (LTP) and long-term depression (LTD) are two prominent forms of synaptic plasticity, both of which are triggered by post-synaptic calcium elevation. To understand how calcium selectively stimulates two opposing processes, we developed a detailed computational model and performed simulations with different calcium input frequencies, amplitudes, and durations. We show that with a total amount of calcium ions kept constant, high frequencies of calcium pulses stimulate calmodulin more efficiently. Calcium input activates both calcineurin and Ca2+/calmodulin-dependent protein kinase II (CaMKII) at all frequencies, but increased frequencies shift the relative activation from calcineurin to CaMKII. Irrespective of amplitude and duration of the inputs, the total amount of calcium ions injected adjusts the sensitivity of the system to calcium input frequencies. At a given frequency, the quantity of CaMKII activated is proportional to the total amount of calcium. Thus, an input of a small amount of calcium at high frequencies can induce the same activation of CaMKII as a larger amount, at lower frequencies. Finally, the extent of activation of CaMKII signals with high calcium frequency is further controlled by other factors, including the availability of calmodulin, and by the potency of phosphatase inhibitors. PMID:22962589

  14. Copper-induced activation of TRP channels promotes extracellular calcium entry and activation of CaMK, PKA, PKC, PKG and CBLPK leading to increased expression of antioxidant enzymes in Ectocarpus siliculosus.

    PubMed

    González, Alberto; Sáez, Claudio A; Morales, Bernardo; Moenne, Alejandra

    2018-05-01

    The existence of functional Transient Receptor Potential (TRP) channels was analyzed in Ectocarpus siliculosus using agonists of human TRPs and specific antagonists of TRPA1, TRPC5, TRPM8 and TRPV; intracellular calcium was detected for 60 min. Increases in intracellular calcium were observed at 13, 29, 39 and 50-52 min, which appeared to be mediated by the activation of TRPM8/V1 at 13 min, TRPV1 at 29 min, TRPA1/V1 at 39 min and TRPA1/C5 at 50-52 min. In addition, intracellular calcium increases appear to be due to extracellular calcium entry, not requiring protein kinase activation. On the other hand, 2.5 μM copper exposure induced increased intracellular calcium at 13, 29, 39 and 51 min, likely due to the activation of a TRPA1/V1 at 13 min, TRPA1/C5/M8 at 29 min, TRPC5/M8 at 39 min, and a TRPC5/V1 at 51 min. The increases in intracellular calcium induced by copper were due to extracellular calcium entry and required protein kinase activation. Furthermore, from 3 to 24 h, copper exposure induced an increase in the level of transcripts encoding antioxidant enzymes such as superoxide dismutase, ascorbate peroxidase, glutathione reductase and peroxiredoxin. The described upregulation decreased with inhibitors of CaMK, PKA, PKC, PKG and CBLPK, as well as with a mixture of TRP inhibitors. Thus, copper induces the activation of TRP channels allowing extracellular calcium entry as well as the activation of CaMK, PKA, PKC, PKG and CBLPK leading to increased expression of genes encoding antioxidant enzymes in E. siliculosus. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  15. Effects of Human Mesenchymal Stem Cells Coculture on Calcium-Induced Differentiation of Normal Human Keratinocytes.

    PubMed

    Sah, Shyam Kishor; Kim, Hae Young; Lee, Ji Hae; Lee, Seong-Wook; Kim, Hyung-Sik; Kim, Yeon-Soo; Kang, Kyung-Sun; Kim, Tae-Yoon

    2017-06-01

    The influence of mesenchymal stem cells (MSCs) on keratinocytes in altered microenvironments is poorly understood. Here, we cocultured umbilical cord blood-derived MSCs with normal human epidermal keratinocytes to evaluate their paracrine effect in the presence of high extracellular calcium (Ca 2+ ) concentration. High Ca 2+ environment to keratinocytes can disrupt normal skin barrier function due to abnormal/premature differentiation of keratinocytes. Surprisingly, we found that MSCs suppress both proliferation and differentiation of keratinocytes under a high Ca 2+ environment in transforming growth factors β1 (TGFβ1)-dependent manner. Furthermore, we determined that MSCs can regulate the mitogen-activated protein kinases, phosphatidylinositol 3-kinase/protein kinase B, and protein kinase C pathways in Ca 2+ -induced differentiated keratinocytes. Knockdown of TGFβ1 from MSCs results in decreased suppression of differentiation with significantly increased proliferation of keratinocytes compared with control MSCs. MSCs-derived TGFβ1 further induced growth inhibition of keratinocyte in high extracellular Ca 2+ environment as analyzed by a decrease in DNA synthesis, accumulation of phosphorylated retinoblastoma protein, cdc2, and increased mRNA level of p21, and independent of TGFβ1/SMAD pathway. Taken together, we found that MSCs-derived TGFβ1 is a critical regulator of keratinocyte function, and involves multiple proximal signaling cascades. Stem Cells 2017;35:1592-1602. © 2017 AlphaMed Press.

  16. Can atorvastatin calcium cause asymptomatic hypercalcemia?

    PubMed

    Ipekçi, Süleyman Hilmi; Baldane, Süleyman; Sözen, Mehmet; Kebapçılar, Levent

    2014-10-01

    The use of statins may have unnatural effects. A 54-year-old woman was admitted to the hospital with an incidental finding of hypercalcemia (10.8 mg/dL). There was no disease other than hyperlipidemia, and the patient had been on a course of atorvastatin calcium 10 mg for 1.5 years. A workup investigation to diagnose the cause of hypercalcemia was completed. The investigation did not reveal any pathological diseases that may have caused the hypercalcemia. The hypercalcemia resolved after atorvastatin-calcium was stopped, and the patient developed hypercalcemia shortly after the initiation of the atorvastatin calcium. Here, we report a clinical case of recurrent hypercalcemia possibly induced by atorvastatin calcium administration.

  17. Calcium mobilization and phosphoinositide turnover in fluoride-activated human neutrophils

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

    Strnad, C.F.; Wong, K.

    1986-05-01

    Fluoride ion, at concentrations above 10 mM, has been found to activate a superoxide production response in human neutrophils which is strongly dependent on the presence of extracellular calcium. In an attempt to further explore the calcium requirement of fluoride-induced neutrophil activation, intracellular calcium concentrations were monitored through use of the fluorescent calcium probe, Quin 2. Fluoride ion, at concentrations between 10 and 20 mM, was found to elicit a rise in intracellular calcium levels which was characterized by a lag period of 4 to 10 min and a prolonged duration of action (greater than 20 min). In contrast, themore » chemotactic peptide, formylmethionyl-leucyl-phenylalanine (FMLP), induced a rise in intracellular calcium concentration which peaked within 1 min. Preincubation of cells with 1 ..mu..g/ml pertussis toxin resulted in inhibition of the FMLP-induced response, but not that elicited by fluoride. Furthermore, anion exchange chromatography indicated that inositol phosphate accumulation occurred in fluoride-treated cells in association with calcium mobilization. Recent evidence suggests that the FMLP receptor is coupled to phospholipase C and phosphoinositide turnover through a guanine nucleotide binding protein susceptible to inhibition by pertussis toxin. Present results suggest that fluoride ion may serve to activate this protein in a manner resistant to inhibition by pertussis toxin.« less

  18. Factors affecting calcium oxalate dihydrate fragmented calculi regrowth

    PubMed Central

    Costa-Bauzá, A; Perelló, J; Isern, B; Sanchis, P; Grases, F

    2006-01-01

    Background The use of extracorporeal shock wave lithotripsy (ESWL) to treat calcium oxalate dihydrate (COD) renal calculi gives excellent fragmentation results. However, the retention of post-ESWL fragments within the kidney remains an important health problem. This study examined the effect of various urinary conditions and crystallization inhibitors on the regrowth of spontaneously-passed post-ESWL COD calculi fragments. Methods Post-ESWL COD calculi fragments were incubated in chambers containing synthetic urine varying in pH and calcium concentration: pH = 5.5 normocalciuria (3.75 mM), pH = 5.5 hypercalciuria (6.25 mM), pH = 6.5 normocalciuria (3.75 mM) or pH = 6.5 hypercalciuria (6.25 mM). Fragment growth was evaluated by measuring increases in weight. Fragment growth was standardized by calculating the relative mass increase. Results Calcium oxalate monohydrate (COM) crystals formed on COD renal calculi fragments under all conditions. Under pH = 5.5 normocalciuria conditions, only COM crystals formed (growth rate = 0.22 ± 0.04 μg/mg·h). Under pH = 5.5 hypercalciuria and under pH = 6.5 normocalciuria conditions, COM crystals and a small number of new COD crystals formed (growth rate = 0.32 ± 0.03 μg/mg·h and 0.35 ± 0.05 μg/mg·h, respectively). Under pH = 6.5 hypercalciuria conditions, large amounts of COD, COM, hydroxyapatite and brushite crystals formed (growth rate = 3.87 ± 0. 34 μg/mg·h). A study of three crystallization inhibitors demonstrated that phytate completely inhibited fragment growth (2.27 μM at pH = 5.5 and 4.55 μM at pH = 6.5, both under hypercalciuria conditions), while 69.0 μM pyrophosphate caused an 87% reduction in mass under pH = 6.5 hypercalciuria conditions. In contrast, 5.29 mM citrate did not inhibit fragment mass increase under pH = 6.5 hypercalciuria conditions. Conclusion The growth rate of COD calculi fragments under pH = 6.5 hypercalciuria conditions was approximately ten times that observed under the other three

  19. Demonstration of the existence of receptor-dependent calcium channels in the platelets

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

    Avdonin, P.V.; Bugrii, E.M.; Cheglakov, I.B.

    1987-01-01

    Recently, with the new methodology of measuring calcium ion concentration in the cytoplasm with the aid of the fluorescent indicator, it has been shown that calcium is a second messenger, mediating the action of many hormones, neuromediators, and other extracellular factors. Another argument in support of the existence of receptor-dependent calcium channels is provided by data on the activation by agonists of the uptake of /sup 45/Ca by the cells. In all the studies cited, the conditions were such that the passage of Ca/sup 2 +/ through the potential-dependent channels was excluded. In this paper, evidence is presented for themore » existence of receptor-dependent calcium channels in the plasma membrane using human platelets as the objects. Two approaches were used. First, the authors determined the binding of /sup 45/Ca by the platelets. In this case, to determine whether /sup 45/Ca passes into the cytoplasm or is adsorbed on the membrane, the authors compared its uptake by simply washed platelets and by platelets in whose cytoplasm buffer capacity for calcium was artificially created with quin 2. The second approach was based on the data of Hallam and Rink, who showed that agonists that increase the calcium level in the platelets induce an intake of Mn/sup 2 +/ ions into the cell in a calcium-free medium.« less

  20. Synergistic Effect of Transient Receptor Potential Antagonist and Amiloride against Maitotoxin Induced Calcium Increase and Cytotoxicity in Human Neuronal Stem Cells.

    PubMed

    Boente-Juncal, Andrea; Vale, Carmen; Alfonso, Amparo; Botana, Luis M

    2018-05-16

    Maitotoxins (MTX) are among the most potent marine toxins identified to date causing cell death trough massive calcium influx. However, the exact mechanism for the MTX-induced calcium entry and cytotoxicity is still unknown. In this work, the effect of MTX-1 on the cytosolic free calcium concentration and cellular viability of human neuronal stem cells was evaluated. MTX elicited a concentration-dependent decrease in cell viability which was already evident after 1 h of treatment with 0.25 nM MTX; however, at a concentration of 0.1 nM, the toxin did not cause cell death even after 14 days of exposure. Moreover, the toxin caused a concentration dependent rise in the cytosolic calcium concentration which was maximal at toxin concentrations of 1 nM and dependent on the presence of extracellular calcium on the bathing solution. Several pharmacological approaches were employed to evaluate the role of canonical transient potential receptor channels (TRPC) on the MTX effects. The results presented here lead to the identification of the TRPC4 channels as contributors to the MTX effects in human neuronal cells. Both, the calcium increase and the cytotoxicity of MTX were either fully (for the calcium increase) or partially (in the case of cytotoxicity) reverted by the blockade of canonical TRPC4 receptors with the selective antagonist ML204. Furthermore, the sodium proton exchanger blocker amiloride also partially inhibited the calcium rise and the cell death elicited by MTX while the combination of amiloride and ML204 fully prevented both the cytotoxicity and the calcium rise elicited by the toxin.

  1. The Roles of Fibroblast Growth Factor (FGF)-23, α-Klotho and Furin Protease in Calcium and Phosphate Homeostasis : A Mini-Review.

    PubMed

    Mattoo, Roshan L

    2014-01-01

    The roles of calcitonin, parathormone and calcitriol in the regulation of plasma calcium and phosphate are well-established. However, in autosomal-dominant hypophosphatemic rickety patients, studies have revealed normal plasma levels of calcium, associated with normal thyroid and parathyroid functions, but decreased levels of phosphate and calcitriol despite adequate reserves of vitamin D. Also, in tumoral calcinosis, persistent hyperphosphatemia with increased levels of 1,25(OH)2D3 have been observed. These studies indicate the involvement of factors other than the ones already known. The first decade of this century/millennium has led to the discovery of the involvement of fibroblast growth factor-23, furin protease and α-klotho in the homeostasis of calcium and phosphate, which is the subject of this mini-review.

  2. Calcium requirements for Asian children and adolescents.

    PubMed

    Lee, Warren Tak Keung; Jiang, Ji

    2008-01-01

    Calcium is important for bone health. Over the last 15 years, reference calcium intakes in Western countries have been revised upwards for maximizing bone mass at skeletal maturity and for prevention of osteoporotic fractures. Some of these reference figures have also been adopted for use in Asian countries. However, the scientific data based on for revising reference calcium intakes in the West was largely based on Caucasians. Limited human studies relating to calcium requirements and bone mineralization have been conducted in Asians in Asia. In children and adolescents, a trial has confirmed no effects of calcium supplementation on bone gains in adolescent girls after 7 years. A meta-analysis has also revealed that calcium supplementation has little beneficial effects on bone gain. Given that genetic factors, hormonal status, body size, bone structure, diets, physical activity, vitamin D status and adaptation could modify calcium retention and bone integrity, these factors need to be considered collectively to promote bone health in Asian populations. Furthermore, studies to identify indigenous foods rich in calcium and high in bioavailability are needed to widen sources of dietary calcium. Ethnic differences in calcium retention, hormonal status, bone structure, bone mineral accretion and peak bone mass are evident among Asians, Caucasians and Blacks in USA. Hence, reference calcium intakes for Asians are likely to be unique and different from those of Caucasians. More research has to be conducted in Asian populations in order to develop appropriate reference calcium intakes for the region.

  3. Role of calcium signaling in epithelial bicarbonate secretion.

    PubMed

    Jung, Jinsei; Lee, Min Goo

    2014-06-01

    Transepithelial bicarbonate secretion plays a key role in the maintenance of fluid and protein secretion from epithelial cells and the protection of the epithelial cell surface from various pathogens. Epithelial bicarbonate secretion is mainly under the control of cAMP and calcium signaling. While the physiological roles and molecular mechanisms of cAMP-induced bicarbonate secretion are relatively well defined, those induced by calcium signaling remain poorly understood in most epithelia. The present review summarizes the current status of knowledge on the role of calcium signaling in epithelial bicarbonate secretion. Specifically, this review introduces how cytosolic calcium signaling can increase bicarbonate secretion by regulating membrane transport proteins and how it synergizes with cAMP-induced mechanisms in epithelial cells. In addition, tissue-specific variations in the pancreas, salivary glands, intestines, bile ducts, and airways are discussed. We hope that the present report will stimulate further research into this important topic. These studies will provide the basis for future medicines for a wide spectrum of epithelial disorders including cystic fibrosis, Sjögren's syndrome, and chronic pancreatitis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Growth Control in Colon Epithelial Cells: Gadolinium Enhances Calcium-Mediated Growth Regulation

    PubMed Central

    Attili, Durga; Jenkins, Brian; Aslam, Muhammad Nadeem; Dame, Michael K.

    2013-01-01

    Gadolinium, a member of the lanthanoid family of transition metals, interacts with calcium-binding sites on proteins and other biological molecules. The overall goal of the present investigation was to determine if gadolinium could enhance calcium-induced epithelial cell growth inhibition in the colon. Gadolinium at concentrations as low as 1–5 µM combined with calcium inhibits proliferation of human colonic epithelial cells more effectively than calcium alone. Gadolinium had no detectable effect on calcium-induced differentiation in the same cells based on change in cell morphology, induction of E-cadherin synthesis, and translocation of E-cadherin from the cytosol to the cell surface. When the colon epithelial cells were treated with gadolinium and then exposed to increased calcium concentrations, movement of extracellular calcium into the cell was suppressed. In contrast, gadolinium treatment had no effect on ionomycin-induced release of stored intracellular calcium into the cytoplasm. Whether these in vitro observations can be translated into an approach for reducing abnormal proliferation in the colonic mucosa (including polyp formation) is not known. These results do, however, provide an explanation for our recent findings that a multi-mineral supplement containing all of the naturally occurring lanthanoid metals including gadolinium are more effective than calcium alone in preventing colon polyp formation in mice on a high-fat diet. PMID:23008064

  5. Growth control in colon epithelial cells: gadolinium enhances calcium-mediated growth regulation.

    PubMed

    Attili, Durga; Jenkins, Brian; Aslam, Muhammad Nadeem; Dame, Michael K; Varani, James

    2012-12-01

    Gadolinium, a member of the lanthanoid family of transition metals, interacts with calcium-binding sites on proteins and other biological molecules. The overall goal of the present investigation was to determine if gadolinium could enhance calcium-induced epithelial cell growth inhibition in the colon. Gadolinium at concentrations as low as 1-5 μM combined with calcium inhibits proliferation of human colonic epithelial cells more effectively than calcium alone. Gadolinium had no detectable effect on calcium-induced differentiation in the same cells based on change in cell morphology, induction of E-cadherin synthesis, and translocation of E-cadherin from the cytosol to the cell surface. When the colon epithelial cells were treated with gadolinium and then exposed to increased calcium concentrations, movement of extracellular calcium into the cell was suppressed. In contrast, gadolinium treatment had no effect on ionomycin-induced release of stored intracellular calcium into the cytoplasm. Whether these in vitro observations can be translated into an approach for reducing abnormal proliferation in the colonic mucosa (including polyp formation) is not known. These results do, however, provide an explanation for our recent findings that a multi-mineral supplement containing all of the naturally occurring lanthanoid metals including gadolinium are more effective than calcium alone in preventing colon polyp formation in mice on a high-fat diet.

  6. Exacerbated immune stress response during experimental magnesium deficiency results from abnormal cell calcium homeostasis.

    PubMed

    Malpuech-Brugère, C; Rock, E; Astier, C; Nowacki, W; Mazur, A; Rayssiguier, Y

    1998-01-01

    The aim of this study was to assess the potential mechanism underlying the enhanced inflammatory processes during magnesium deficit. In this study, exacerbated response to live bacteria and platelet activating factors was shown in rats fed a magnesium-deficient diet. Peritoneal cells from these animals also showed enhanced superoxide anion production and calcium mobilising potency following in vitro stimulation. The latter effect occurred very early in the course of magnesium deficiency. These studies first showed that an abnormal calcium handling induced by extracellular magnesium depression in vivo may be at the origin of exacerbated inflammatory response.

  7. Diagram of Calcium Movement in the Human Body

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This diagram shows the normal pathways of calcium movement in the body and indicates changes (green arrows) seen during preliminary space flight experiments. Calcium plays a central role because 1) it gives strength and structure to bone and 2) all types of cells require it to function normally. To better understand how and why weightlessness induces bone loss, astronauts have participated in a study of calcium kinetics -- that is, the movement of calcium through the body, including absorption from food, and its role in the formation and breakdown of bone.

  8. Calcium Induces Long-Term Legacy Effects in a Subalpine Ecosystem

    PubMed Central

    Schaffner, Urs; Alewell, Christine; Eschen, René; Matthies, Diethart; Spiegelberger, Thomas; Hegg, Otto

    2012-01-01

    Human activities have transformed a significant proportion of the world’s land surface, with profound effects on ecosystem processes. Soil applications of macronutrients such as nitrate, phosphorus, potassium or calcium are routinely used in the management of croplands, grasslands and forests to improve plant health or increase productivity. However, while the effects of continuous fertilization and liming on terrestrial ecosystems are well documented, remarkably little is known about the legacy effect of historical fertilization and liming events in terrestrial ecosystems and of the mechanisms involved. Here, we show that more than 70 years after the last application of lime on a subalpine grassland, all major soil and plant calcium pools were still significantly larger in limed than in unlimed plots, and that the resulting shift in the soil calcium/aluminium ratio continues to affect ecosystem services such as primary production. The difference in the calcium content of the vegetation and the topmost 10 cm of the soil in limed vs. unlimed plots amounts to approximately 19.5 g m−2, equivalent to 16.3% of the amount that was added to the plots some 70 years ago. In contrast, plots that were treated with nitrogen-phosphorus-potassium fertilizer in the 1930s did not differ from unfertilized plots in any of the soil and vegetation characteristics measured. Our findings suggest that the long-term legacy effect of historical liming is due to long-term storage of added calcium in stable soil pools, rather than a general increase in nutrient availability. Our results demonstrate that single applications of calcium in its carbonated form can profoundly and persistently alter ecosystem processes and services in mountain ecosystems. PMID:23284779

  9. Electrophoretic mobility shift in native gels indicates calcium-dependent structural changes of neuronal calcium sensor proteins.

    PubMed

    Viviano, Jeffrey; Krishnan, Anuradha; Wu, Hao; Venkataraman, Venkat

    2016-02-01

    In proteins of the neuronal calcium sensor (NCS) family, changes in structure as well as function are brought about by the binding of calcium. In this article, we demonstrate that these structural changes, solely due to calcium binding, can be assessed through electrophoresis in native gels. The results demonstrate that the NCS proteins undergo ligand-dependent conformational changes that are detectable in native gels as a gradual decrease in mobility with increasing calcium but not other tested divalent cations such as magnesium, strontium, and barium. Surprisingly, such a gradual change over the entire tested range is exhibited only by the NCS proteins but not by other tested calcium-binding proteins such as calmodulin and S100B, indicating that the change in mobility may be linked to a unique NCS family feature--the calcium-myristoyl switch. Even within the NCS family, the changes in mobility are characteristic of the protein, indicating that the technique is sensitive to the individual features of the protein. Thus, electrophoretic mobility on native gels provides a simple and elegant method to investigate calcium (small ligand)-induced structural changes at least in the superfamily of NCS proteins. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Formate oxidation-driven calcium carbonate precipitation by Methylocystis parvus OBBP.

    PubMed

    Ganendra, Giovanni; De Muynck, Willem; Ho, Adrian; Arvaniti, Eleni Charalampous; Hosseinkhani, Baharak; Ramos, Jose Angel; Rahier, Hubert; Boon, Nico

    2014-08-01

    Microbially induced carbonate precipitation (MICP) applied in the construction industry poses several disadvantages such asammonia release to the air and nitric acid production. An alternative MICP from calcium formate by Methylocystis parvus OBBP is presented here to overcome these disadvantages. To induce calcium carbonate precipitation, M. parvus was incubated at different calcium formate concentrations and starting culture densities. Up to 91.4% ± 1.6% of the initial calcium was precipitated in the methane-amended cultures compared to 35.1% ± 11.9% when methane was not added. Because the bacteria could only utilize methane for growth, higher culture densities and subsequently calcium removals were exhibited in the cultures when methane was added. A higher calcium carbonate precipitate yield was obtained when higher culture densities were used but not necessarily when more calcium formate was added. This was mainly due to salt inhibition of the bacterial activity at a high calcium formate concentration. A maximum 0.67 ± 0.03 g of CaCO3 g of Ca(CHOOH)2(-1) calcium carbonate precipitate yield was obtained when a culture of 10(9) cells ml(-1) and 5 g of calcium formate liter(-)1 were used. Compared to the current strategy employing biogenic urea degradation as the basis for MICP, our approach presents significant improvements in the environmental sustainability of the application in the construction industry.

  11. Formate Oxidation-Driven Calcium Carbonate Precipitation by Methylocystis parvus OBBP

    PubMed Central

    Ganendra, Giovanni; De Muynck, Willem; Ho, Adrian; Arvaniti, Eleni Charalampous; Hosseinkhani, Baharak; Ramos, Jose Angel; Rahier, Hubert

    2014-01-01

    Microbially induced carbonate precipitation (MICP) applied in the construction industry poses several disadvantages such as ammonia release to the air and nitric acid production. An alternative MICP from calcium formate by Methylocystis parvus OBBP is presented here to overcome these disadvantages. To induce calcium carbonate precipitation, M. parvus was incubated at different calcium formate concentrations and starting culture densities. Up to 91.4% ± 1.6% of the initial calcium was precipitated in the methane-amended cultures compared to 35.1% ± 11.9% when methane was not added. Because the bacteria could only utilize methane for growth, higher culture densities and subsequently calcium removals were exhibited in the cultures when methane was added. A higher calcium carbonate precipitate yield was obtained when higher culture densities were used but not necessarily when more calcium formate was added. This was mainly due to salt inhibition of the bacterial activity at a high calcium formate concentration. A maximum 0.67 ± 0.03 g of CaCO3 g of Ca(CHOOH)2−1 calcium carbonate precipitate yield was obtained when a culture of 109 cells ml−1 and 5 g of calcium formate liter−1 were used. Compared to the current strategy employing biogenic urea degradation as the basis for MICP, our approach presents significant improvements in the environmental sustainability of the application in the construction industry. PMID:24837386

  12. Calcium Supplements and Cardiovascular Disease: A Review.

    PubMed

    Waldman, Talya; Sarbaziha, Raheleh; Merz, C Noel Bairey; Shufelt, Chrisandra

    2015-07-01

    Dietary or supplemental calcium intake has long been encouraged for optimal bone health. However, more recently, the safety of calcium supplementation has been questioned because of a possible association between supplemental calcium and cardiovascular risk. Whereas calcium may have a beneficial or neutral effect on cardiovascular risk factors such as blood pressure, cholesterol, weight, and diabetes, available evidence does not provide a definitive answer for an association with cardiovascular disease (CVD). To date, no calcium trials have studied cardiovascular disease as a primary end point, and larger trials with longer follow-up are needed. In this review, we present results from observational studies and randomized controlled trials (RCTs) that have evaluated calcium intake (dietary or supplemental) in relation to cardiovascular risk factors and cardiovascular disease as a secondary outcome. Results from RCTs are mixed regarding CVD risk in those using supplemental calcium with or without vitamin D, and more large-scale randomized trials designed specifically with CVD as the primary end point are needed. Evidence suggests that it is reasonable to encourage adequate dietary calcium intake, especially for postmenopausal women who are at greatest risk for osteoporotic fracture.

  13. Simvastatin Potently Induces Calcium-dependent Apoptosis of Human Leiomyoma Cells*

    PubMed Central

    Borahay, Mostafa A.; Kilic, Gokhan S.; Yallampalli, Chandrasekha; Snyder, Russell R.; Hankins, Gary D. V.; Al-Hendy, Ayman; Boehning, Darren

    2014-01-01

    Statins are drugs commonly used for the treatment of high plasma cholesterol levels. Beyond these well known lipid-lowering properties, they possess broad-reaching effects in vivo, including antitumor effects. Statins inhibit the growth of multiple tumors. However, the mechanisms remain incompletely understood. Here we show that simvastatin inhibits the proliferation of human leiomyoma cells. This was associated with decreased mitogen-activated protein kinase signaling and multiple changes in cell cycle progression. Simvastatin potently stimulated leiomyoma cell apoptosis in a manner mechanistically dependent upon apoptotic calcium release from voltage-gated calcium channels. Therefore, simvastatin possesses antitumor effects that are dependent upon the apoptotic calcium release machinery. PMID:25359773

  14. Comparison of the adjuvant activity of aluminum hydroxide and calcium phosphate on the antibody response towards Bothrops asper snake venom.

    PubMed

    Olmedo, Hidekel; Herrera, María; Rojas, Leonardo; Villalta, Mauren; Vargas, Mariángela; Leiguez, Elbio; Teixeira, Catarina; Estrada, Ricardo; Gutiérrez, José María; León, Guillermo; Montero, Mavis L

    2014-01-01

    The adjuvanticity of aluminum hydroxide and calcium phosphate on the antibody response in mice towards the venom of the snake Bothrops asper was studied. It was found that, in vitro, most of the venom proteins are similarly adsorbed by both mineral salts, with the exception of some basic phospholipases A2, which are better adsorbed by calcium phosphate. After injection, the adjuvants promoted a slow release of the venom, as judged by the lack of acute toxicity when lethal doses of venom were administered to mice. Leukocyte recruitment induced by the venom was enhanced when it was adsorbed on both mineral salts; however, venom adsorbed on calcium phosphate induced a higher antibody response towards all tested HPLC fractions of the venom. On the other hand, co-precipitation of venom with calcium phosphate was the best strategy for increasing: (1) the capacity of the salt to couple venom proteins in vitro; (2) the venom ability to induce leukocyte recruitment; (3) phagocytosis by macrophages; and (4) a host antibody response. These findings suggest that the chemical nature is not the only one determining factor of the adjuvant activity of mineral salts.

  15. The tobacco-specific carcinogen-operated calcium channel promotes lung tumorigenesis via IGF2 exocytosis in lung epithelial cells.

    PubMed

    Boo, Hye-Jin; Min, Hye-Young; Jang, Hyun-Ji; Yun, Hye Jeong; Smith, John Kendal; Jin, Quanri; Lee, Hyo-Jong; Liu, Diane; Kweon, Hee-Seok; Behrens, Carmen; Lee, J Jack; Wistuba, Ignacio I; Lee, Euni; Hong, Waun Ki; Lee, Ho-Young

    2016-09-26

    Nicotinic acetylcholine receptors (nAChRs) binding to the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) induces Ca 2+ signalling, a mechanism that is implicated in various human cancers. In this study, we investigated the role of NNK-mediated Ca 2+ signalling in lung cancer formation. We show significant overexpression of insulin-like growth factors (IGFs) in association with IGF-1R activation in human preneoplastic lung lesions in smokers. NNK induces voltage-dependent calcium channel (VDCC)-intervened calcium influx in airway epithelial cells, resulting in a rapid IGF2 secretion via the regulated pathway and thus IGF-1R activation. Silencing nAChR, α1 subunit of L-type VDCC, or various vesicular trafficking curators, including synaptotagmins and Rabs, or blockade of nAChR/VDCC-mediated Ca 2+ influx significantly suppresses NNK-induced IGF2 exocytosis, transformation and tumorigenesis of lung epithelial cells. Publicly available database reveals inverse correlation between use of calcium channel blockers and lung cancer diagnosis. Our data indicate that NNK disrupts the regulated pathway of IGF2 exocytosis and promotes lung tumorigenesis.

  16. Glycolytic intermediates induce amorphous calcium carbonate formation in crustaceans.

    PubMed

    Sato, Ai; Nagasaka, Seiji; Furihata, Kazuo; Nagata, Shinji; Arai, Isao; Saruwatari, Kazuko; Kogure, Toshihiro; Sakuda, Shohei; Nagasawa, Hiromichi

    2011-04-01

    It has been thought that phosphorus in biominerals made of amorphous calcium carbonate (ACC) might be related to ACC formation, but no such phosphorus-containing compounds have ever been identified. Crustaceans use ACC biominerals in exoskeleton and gastroliths so that they will have easy access to calcium carbonate inside the body before and after molting. We have identified phosphoenolpyruvate and 3-phosphoglycerate, intermediates of the glycolytic pathway, in exoskeleton and gastroliths and found them important for stabilizing ACC.

  17. Tetany: quantitative interrelationships between calcium and alkalosis.

    PubMed

    Edmondson, J W; Brashear, R E; Li, T K

    1975-04-01

    Tetany occurs with hypocalcemia and alkalosis or both. The interrelationship of calcium and acid-base balance necessary for inducing tetany, the role of the central nervous system, and the rate of development of hypocalcemia have been investigated. Tetany occurred in less than 50 percent of one group of dogs made alkalotic by hyperventilation or made hypocalcemic by infusion of ethylene glycol-bis(beta-amino ethyl ether) N, N'-tetraacetate. In contrast, hypocalcemia combined with hypocapnic alkalosis always produced tetany. Slowly evolving hypocalcemia was achieved inanother group of dogs by thyroparathyroidectomy, and tetany was induced postoperatively by hypocapnic alkalosis. An identical relationship between serum calcium ion concentration and arterial pH or CO2 tension was found in both groups. Tetany could not be related to the cerebrospinal fluid (CSF) calcium ion content in either group. Hypocalcemia and alkalosis are therefore coparticipants in the development of tetany and are independent of the rate of development of hypocalcemia and of CSF calcium ion concentration. The importance of alkalosis in tetany with hypoparathyroidism is emphasized.

  18. Inhibition of 4NQO-Induced Oral Carcinogenesis by Dietary Oyster Shell Calcium

    PubMed Central

    Chen, Ying; Jiang, Yi; Liao, Liyan; Zhu, Xiaoxin; Tang, Shengan; Yang, Qing; Sun, Lihua; Li, Yujie; Gao, Shuangrong; Xie, Zhongjian

    2015-01-01

    Oyster has gained much attention recently for its anticancer activity but it is unclear whether calcium, the major antitumor ingredient in oyster shell, is responsible for the anticarcinogenic role of the oyster. To address this issue, C57BL/6 mice were fed with the carcinogen 4-nitroquinoline-1-oxide (4NQO, 50 µg/mL) and normal diet or a diet containing oyster powder, oyster calcium, or calcium depleted oyster powder. The tongue tissue specimens isolated from these mice were histologically evaluated for hyperplasia, dysplasia, and papillary lesions, and then analyzed for proliferation and differentiation markers by immunohistochemistry. The results showed that mice on the diet containing oyster calcium significantly reduced rates of tumors in the tongue and proliferation and enhanced differentiation in the oral epithelium compared with the diet containing calcium depleted oyster powder. These results suggest that calcium in oyster plays a critical role in suppressing formation of oral squamous cell carcinoma and proliferation and promoting differentiation of the oral epithelium. PMID:26293805

  19. Amyotrophic lateral sclerosis immunoglobulins increase intracellular calcium in a motoneuron cell line.

    PubMed

    Colom, L V; Alexianu, M E; Mosier, D R; Smith, R G; Appel, S H

    1997-08-01

    A hybrid motoneuron cell line (VSC4.1) was used as a model system to study the relationship between alterations in intracellular calcium and subsequent cell death induced by immunoglobulin fractions purified from sera of patients with ALS. Using fluo-3 fluorescence imaging, immunoglobulins from 8 of 10 patients with ALS were found to induce transient increases in intracellular calcium ([Ca2+]i) in differentiated VSC4.1 cells. These transient [Ca2+]i increases required extracellular calcium entry through voltage-gated calcium channels sensitive to synthetic FTX and to high concentrations (>1 microM) of omega-agatoxin IVa. The incidence of transient [Ca2+]i increases induced by ALS immunoglobulins correlated with the extent of cytotoxicity induced by the same ALS immunoglobulins in parallel cultures of VSC4.1 cells. Furthermore, manipulations which blocked transient [Ca2+]i increases (addition of synthetic FTX or omega-agatoxin IVa) also inhibited the cytotoxic effects of ALS immunoglobulins. No transient calcium increases were observed in VSC4.1 cells following addition of immunoglobulins from 7 neurologic disease control patients. However, transient [Ca2+]i increases were observed following addition of immunoglobulins from 4 of 5 patients with myasthenia gravis (MG). The [Ca2+]i changes induced by MG immunoglobulins were not blocked by s-FTX, suggesting that they result from a different mechanism than those induced by ALS immunoglobulins. These results suggest that immunoglobulins from patients with ALS can induce transient increases in intracellular calcium in a motoneuron cell line, which may represent early events in the cascade of processes leading to injury and death of susceptible cells.

  20. The influence of calcium and magnesium in drinking water and diet on cardiovascular risk factors in individuals living in hard and soft water areas with differences in cardiovascular mortality

    PubMed Central

    Nerbrand, Christina; Agréus, Lars; Lenner, Ragnhild Arvidsson; Nyberg, Per; Svärdsudd, Kurt

    2003-01-01

    Background The role of water hardness as a risk factor for cardiovascular disease has been widely investigated and evaluated as regards regional differences in cardiovascular disease. This study was performed to evaluate the relation between calcium and magnesium in drinking water and diet and risk factors for cardiovascular disease in individuals living in hard and soft water areas with considerable differences in cardiovascular mortality. Methods A random sample of 207 individuals living in two municipalities characterised by differences in cardiovascular mortality and water hardness was invited for an examination including a questionnaire about health, social and living conditions and diet. Intake of magnesium and calcium was calculated from the diet questionnaire with special consideration to the use of local water. Household water samples were delivered by each individual and were analysed for magnesium and calcium. Results In the total sample, there were positive correlations between the calcium content in household water and systolic blood pressure (SBP) and negative correlations with s-cholesterol and s-LDL-cholesterol. No correlation was seen with magnesium content in household water to any of the risk factors. Calcium content in diet showed no correlation to cardiovascular risk factors. Magnesium in diet was positively correlated to diastolic blood pressure (DBP). In regression analyses controlled for age and sex 18.5% of the variation in SBP was explained by the variation in BMI, HbA1c and calcium content in water. Some 27.9% of the variation in s-cholesterol could be explained by the variation in s-triglycerides (TG), and calcium content in water. Conclusions This study of individuals living in soft and hard water areas showed significant correlations between the content of calcium in water and major cardiovascular risk factors. This was not found for magnesium in water or calcium or magnesium in diet. Regression analyses indicated that calcium content

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

    PubMed

    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

  2. Nimodipine, an L-type calcium channel blocker attenuates mitochondrial dysfunctions to protect against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinsonism in mice.

    PubMed

    Singh, Alpana; Verma, Poonam; Balaji, Gillela; Samantaray, Supriti; Mohanakumar, Kochupurackal P

    2016-10-01

    Parkinson's disease (PD), the most common progressive neurodegenerative movement disorder, results from loss of dopaminergic neurons of substantia nigra pars compacta. These neurons exhibit Cav1.3 channel-dependent pacemaking activity. Epidemiological studies suggest reduced risk for PD in population under long-term antihypertensive therapy with L-type calcium channel antagonists. These prompted us to investigate nimodipine, an L-type calcium channel blocker for neuroprotective effect in cellular and animal models of PD. Nimodipine (0.1-10 μM) significantly attenuated 1-methyl-4-phenyl pyridinium ion-induced loss in mitochondrial morphology, mitochondrial membrane potential and increases in intracellular calcium levels in SH-SY5Y neuroblastoma cell line as measured respectively employing Mitotracker green staining, TMRM, and Fura-2 fluorescence, but only a feeble neuroprotective effect was observed in MTT assay. Nimodipine dose-dependently reduced 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonian syndromes (akinesia and catalepsy) and loss in swimming ability in Balb/c mice. It attenuated MPTP-induced loss of dopaminergic tyrosine hydroxylase positive neurons in substantia nigra, improved mitochondrial oxygen consumption and inhibited reactive oxygen species production in the striatal mitochondria measured using dichlorodihydrofluorescein fluorescence, but failed to block striatal dopamine depletion. These results point to an involvement of L-type calcium channels in MPTP-induced dopaminergic neuronal death in experimental parkinsonism and more importantly provide evidences for nimodipine to improve mitochondrial integrity and function. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Antenatal calcium intake in Malaysia.

    PubMed

    Mahdy, Zaleha Abdullah; Basri, Hashimah; Md Isa, Zaleha; Ahmad, Shuhaila; Shamsuddin, Khadijah; Mohd Amin, Rahmah

    2014-04-01

    To determine the adequacy of antenatal calcium intake in Malaysia, and the influencing factors. A cross-sectional study was conducted among postnatal women who delivered in two tertiary hospitals. Data were collected from antenatal cards, hospital documents and diet recall on daily milk and calcium intake during pregnancy. SPSS version 19.0 was used for statistical analyses. A total of 150 women were studied. The total daily calcium intake was 834 ± 43 mg (mean ± standard error of the mean), but the calcium intake distribution curve was skewed to the right with a median intake of 725 mg daily. When calcium intake from milk and calcium supplements was excluded, the daily dietary calcium intake was only 478 ± 25 mg. Even with inclusion of milk and calcium supplements, more than a third (n=55 or 36.7%) of the women consumed less than 600 mg calcium in their daily diet. The adequacy of daily calcium intake was not influenced by maternal age, ethnicity, income or maternal job or educational status as well as parity. The daily dietary calcium intake of the Malaysian antenatal population is far from adequate without the addition of calcium supplements and milk. © 2013 The Authors. Journal of Obstetrics and Gynaecology Research © 2013 Japan Society of Obstetrics and Gynecology.

  4. Hyperthyroidism enhances 5-HT-induced contraction of the rat pulmonary artery: role of calcium-activated chloride channel activation.

    PubMed

    Oriowo, Mabayoje A; Oommen, Elsie; Khan, Islam

    2011-11-01

    Experimentally-induced hyperthyroidism in rodents is associated with signs and symptoms of pulmonary hypertension. The main objective of the present study was to investigate the effect of thyroxine-induced pulmonary hypertension on the contractile response of the pulmonary artery to 5-HT and the possible underlying signaling pathway. 5-HT concentration-dependently contracted artery segments from control and thyroxine-treated rats with pD(2) values of 5.04 ± 0.19 and 5.34 ± 0.14, respectively. The maximum response was significantly greater in artery segments from thyroxine-treated rats. Neither BW 723C86 (5-HT(2B)-receptor agonist) nor CP 93129 (5-HT(1B)-receptor agonist) contracted ring segments of the pulmonary artery from control and thyroxine-treated rats at concentrations up to 10(-4)M. There was no significant difference in the level of expression of 5-HT(2A)-receptor protein between the two groups. Ketanserin (3 × 10(-8)M) produced a rightward shift of the concentration-response curve to 5-HT in both groups with equal potency (-logK(B) values were 8.1 ± 0.2 and 7.9 ± 0.1 in control and thyroxine-treated rats, respectively). Nifedipine (10(-6)M) inhibited 5-HT-induced contractions in artery segments from control and thyroxine-treated rats and was more effective against 5-HT-induced contraction in artery segments for thyroxine-treated rats. The calcium-activated chloride channel blocker, niflumic acid (10(-4)M) also inhibited 5-HT-induced contractions in artery segments from control and thyroxine-treated rats and was more effective against 5-HT-induced contraction in artery segments for thyroxine-treated rats. It was concluded that hyperthyroidism enhanced 5-HT-induced contractions of the rat pulmonary artery by a mechanism involving increased activity of calcium-activated chloride channels. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Stimulation of fibroblast growth factor 23 by metabolic acidosis requires osteoblastic intracellular calcium signaling and prostaglandin synthesis.

    PubMed

    Krieger, Nancy S; Bushinsky, David A

    2017-10-01

    Serum fibroblast growth factor 23 (FGF23) increases progressively in chronic kidney disease (CKD) and is associated with increased mortality. FGF23 is synthesized in osteoblasts and osteocytes; however, the factors regulating its production are not clear. Patients with CKD have decreased renal acid excretion leading to metabolic acidosis (MET). During MET, acid is buffered by bone with release of mineral calcium (Ca) and phosphate (P). MET increases intracellular Ca signaling and cyclooxygenase 2 (COX2)-induced prostaglandin production in the osteoblast, leading to decreased bone formation and increased bone resorption. We found that MET directly stimulates FGF23 in mouse bone organ cultures and primary osteoblasts. We hypothesized that MET increases FGF23 through similar pathways that lead to bone resorption. Neonatal mouse calvariae were incubated in neutral (NTL, pH = 7.44, Pco 2 = 38 mmHg, [HCO 3 - ] = 27 mM) or acid (MET, pH = 7.18, Pco 2 = 37 mmHg, [HCO 3 - ] = 13 mM) medium without or with 2-APB (50 μM), an inhibitor of intracellular Ca signaling or NS-398 (1 μM), an inhibitor of COX2. Each agent significantly inhibited MET stimulation of medium FGF23 protein and calvarial FGF23 RNA as well as bone resorption at 48 h. To exclude the potential contribution of MET-induced bone P release, we utilized primary calvarial osteoblasts. In these cells each agent inhibited MET stimulation of FGF23 RNA expression at 6 h. Thus stimulation of FGF23 by MET in mouse osteoblasts utilizes the same initial signaling pathways as MET-induced bone resorption. Therapeutic interventions directed toward correction of MET, especially in CKD, have the potential to not only prevent bone resorption but also lower FGF23 and perhaps decrease mortality. Copyright © 2017 the American Physiological Society.

  6. Calcium metabolism in health and disease.

    PubMed

    Peacock, Munro

    2010-01-01

    This brief review focuses on calcium balance and homeostasis and their relationship to dietary calcium intake and calcium supplementation in healthy subjects and patients with chronic kidney disease and mineral bone disorders (CKD-MBD). Calcium balance refers to the state of the calcium body stores, primarily in bone, which are largely a function of dietary intake, intestinal absorption, renal excretion, and bone remodeling. Bone calcium balance can be positive, neutral, or negative, depending on a number of factors, including growth, aging, and acquired or inherited disorders. Calcium homeostasis refers to the hormonal regulation of serum ionized calcium by parathyroid hormone, 1,25-dihydroxyvitamin D, and serum ionized calcium itself, which together regulate calcium transport at the gut, kidney, and bone. Hypercalcemia and hypocalcemia indicate serious disruption of calcium homeostasis but do not reflect calcium balance on their own. Calcium balance studies have determined the dietary and supplemental calcium requirements needed to optimize bone mass in healthy subjects. However, similar studies are needed in CKD-MBD, which disrupts both calcium balance and homeostasis, because these data in healthy subjects may not be generalizable to this patient group. Importantly, increasing evidence suggests that calcium supplementation may enhance soft tissue calcification and cardiovascular disease in CKD-MBD. Further research is needed to elucidate the risks and mechanisms of soft tissue calcification with calcium supplementation in both healthy subjects and CKD-MBD patients.

  7. Carbachol induces burst firing of dopamine cells in the ventral tegmental area by promoting calcium entry through L-type channels in the rat

    PubMed Central

    Zhang, Lei; Liu, Yudan; Chen, Xihua

    2005-01-01

    Enhanced activity of the central dopamine system has been implicated in many psychiatric disorders including schizophrenia and addiction. Besides terminal mechanisms that boost dopamine levels at the synapse, the cell body of dopamine cells enhances terminal dopamine concentration through encoding action potentials in bursts. This paper presents evidence that burst firing of dopamine cells in the ventral tegmental area was under cholinergic control using nystatin-perforated patch clamp recording from slice preparations. The non-selective cholinergic agonist carbachol excited the majority of recorded neurones, an action that was not affected by blocking glutamate and GABA ionotropic receptors. Twenty per cent of dopamine cells responded to carbachol with robust bursting, an effect mediated by both muscarinic and nicotinic cholinoceptors postsynaptically. Burst firing induced as such was completely dependent on calcium entry as it could be blocked by cadmium and more specifically the L-type blocker nifedipine. In the presence of the sodium channel blocker tetrodotoxin, carbachol induced membrane potential oscillation that had similar kinetics and frequency as burst firing cycles and could also be blocked by cadmium and nifedipine. Direct activation of the L-type channel with Bay K8644 induced strong bursting which could be blocked by nifedipine but not by depleting internal calcium stores. These results indicate that carbachol increases calcium entry into the postsynaptic cell through L-type channels to generate calcium-dependent membrane potential oscillation and burst firing. This could establish the L-type channel as a target for modulating the function of the central dopamine system in disease conditions. PMID:16081481

  8. Aminoglycoside antibiotics as a tool for the study of the biological role of calcium ions. Historical overview.

    PubMed

    Corrado, A P; de Morais, I P; Prado, W A

    1989-01-01

    Beginning with the pioneering work of Vital-Brazil and Corrado (1957), which suggested a possible interaction between aminoglycoside antibiotics (AGA) and calcium ions at the neuromuscular junction, the authors review the studies that demonstrated the existence of a competitive antagonism between AGA and calcium ions. In view of the low liposolubility of AGA and their inability to cross biological membranes, this antagonism seems to occur exclusively at calcium-binding sites at the level of the outer opening of calcium channels of the N-subtype, which are also the sites of interaction of omega-conotoxin. Being highly water soluble, AGA are easily removed from their binding sites with a consequent rapid reversal of their effects, a factor of primary importance to explain their wide use as tools in the pharmacological analysis of the study of the biological role of calcium ion on the membrane's outer surface. This use has advantages over the use of inorganic di- and trivalent cations such as Mg2+, Mn2+, Cd2+, Ni2+, La3+, etc., since the latter, though they are considered to be the most specific competitive antagonists of calcium ions, may induce biphasic effects due to their ability to cross the membranes and replace calcium and/or increase intracellular calcium concentration. The performance of AGA is also superior when compared with the so-called "specific" organic calcium antagonists--verapamil and nifedipine derivatives--since the latter, in addition to inducing possible biphasic effects, antagonize calcium in a non-competitive manner. Finally, the authors remark that AGA-Ca2+ antagonism relevance is not limited only to basic aspects and that it may have therapeutic implications since it provides alternatives for reducing the toxic adverse effects of this important group of antibiotics.

  9. Analysis of calcium-induced effects on the conformation of fengycin.

    PubMed

    Nasir, Mehmet Nail; Laurent, Pascal; Flore, Christelle; Lins, Laurence; Ongena, Marc; Deleu, Magali

    2013-06-01

    Fengycin is a natural lipopeptide with antifungal and eliciting properties and able to inhibit the activity of phospholipase A2. A combination of CD, FT-IR, NMR and fluorescence spectroscopic techniques was applied to elucidate its conformation in a membrane-mimicking environment and to investigate the effect of calcium ions on it. We mainly observed that fengycin adopts a turn conformation. Our results showed that calcium ions are bound by the two charged glutamates. The calcium binding has an influence on the fengycin conformation and more particularly, on the environment of the tyrosine residues. The modulation of the fengycin conformation by the environmental conditions may influence its biological properties. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Kit W-sh Mutation Prevents Cancellous Bone Loss during Calcium Deprivation.

    PubMed

    Lotinun, Sutada; Suwanwela, Jaijam; Poolthong, Suchit; Baron, Roland

    2018-01-01

    Calcium is essential for normal bone growth and development. Inadequate calcium intake increases the risk of osteoporosis and fractures. Kit ligand/c-Kit signaling plays an important role in regulating bone homeostasis. Mice with c-Kit mutations are osteopenic. The present study aimed to investigate whether impairment of or reduction in c-Kit signaling affects bone turnover during calcium deprivation. Three-week-old male WBB6F1/J-Kit W /Kit W-v /J (W/W v ) mice with c-Kit point mutation, Kit W-sh /HNihrJaeBsmJ (W sh /W sh ) mice with an inversion mutation in the regulatory elements upstream of the c-Kit promoter region, and their wild-type controls (WT) were fed either a normal (0.6% calcium) or a low calcium diet (0.02% calcium) for 3 weeks. μCT analysis indicated that both mutants fed normal calcium diet had significantly decreased cortical thickness and cancellous bone volume compared to WT. The low calcium diet resulted in a comparable reduction in cortical bone volume and cortical thickness in the W/W v and W sh /W sh mice, and their corresponding controls. As expected, the low calcium diet induced cancellous bone loss in the W/W v mice. In contrast, W sh /W sh cancellous bone did not respond to this diet. This c-Kit mutation prevented cancellous bone loss by antagonizing the low calcium diet-induced increase in osteoblast and osteoclast numbers in the W sh /W sh mice. Gene expression profiling showed that calcium deficiency increased Osx, Ocn, Alp, type I collagen, c-Fms, M-CSF, and RANKL/OPG mRNA expression in controls; however, the W sh mutation suppressed these effects. Our findings indicate that although calcium restriction increased bone turnover, leading to osteopenia, the decreased c-Kit expression levels in the W sh /W sh mice prevented the low calcium diet-induced increase in cancellous bone turnover and bone loss but not the cortical bone loss.

  11. Calcium Intake: A Lifelong Proposition.

    ERIC Educational Resources Information Center

    Amschler, Denise H.

    1985-01-01

    This article reviews the current problem of low calcium intake in the United States among all age groups, the role of calcium in the formation and maintenance of bone mass, and major factors influencing absorption. Osteoporosis is discussed, and current recommendations for Recommended Dietary allowance are provided. (Author/MT)

  12. Autophagy degrades hypoxia inducible factors

    PubMed Central

    DePavia, Adela; Jonasch, Eric; Liu, Xian-De

    2016-01-01

    ABSTRACT Hypoxia inducible factors are subjected to degradation by the ubiquitin-proteasome system (UPS), macroautophagy, and chaperone-mediated autophagy. The E3 ligases, ubiquitination, autophagy receptor proteins, and oxygen are determinants that direct hypoxia-inducible factors to different degradation pathways. PMID:27308629

  13. Altered elementary calcium release events and enhanced calcium release by thymol in rat skeletal muscle.

    PubMed

    Szentesi, Péter; Szappanos, Henrietta; Szegedi, Csaba; Gönczi, Monika; Jona, István; Cseri, Julianna; Kovács, László; Csernoch, László

    2004-03-01

    The effects of thymol on steps of excitation-contraction coupling were studied on fast-twitch muscles of rodents. Thymol was found to increase the depolarization-induced release of calcium from the sarcoplasmic reticulum, which could not be attributed to a decreased calcium-dependent inactivation of calcium release channels/ryanodine receptors or altered intramembrane charge movement, but rather to a more efficient coupling of depolarization to channel opening. Thymol increased ryanodine binding to heavy sarcoplasmic reticulum vesicles, with a half-activating concentration of 144 micro M and a Hill coefficient of 1.89, and the open probability of the isolated and reconstituted ryanodine receptors, from 0.09 +/- 0.03 to 0.22 +/- 0.04 at 30 micro M. At higher concentrations the drug induced long-lasting open events on a full conducting state. Elementary calcium release events imaged using laser scanning confocal microscopy in the line-scan mode were reduced in size, 0.92 +/- 0.01 vs. 0.70 +/- 0.01, but increased in duration, 56 +/- 1 vs. 79 +/- 1 ms, by 30 micro M thymol, with an increase in the relative proportion of lone embers. Higher concentrations favored long events, resembling embers in control, with duration often exceeding 500 ms. These findings provide direct experimental evidence that the opening of a single release channel will generate an ember, rather than a spark, in mammalian skeletal muscle.

  14. Space flight calcium: implications for astronaut health, spacecraft operations, and Earth.

    PubMed

    Smith, Scott M; McCoy, Torin; Gazda, Daniel; Morgan, Jennifer L L; Heer, Martina; Zwart, Sara R

    2012-12-18

    The space flight environment is known to induce bone loss and, subsequently, calcium loss. The longer the mission, generally the more bone and calcium are lost. This review provides a history of bone and calcium studies related to space flight and highlights issues related to calcium excretion that the space program must consider so that urine can be recycled. It also discusses a novel technique using natural stable isotopes of calcium that will be helpful in the future to determine calcium and bone balance during space flight.

  15. The interactive roles of zinc and calcium in mitochondrial dysfunction and neurodegeneration.

    PubMed

    Pivovarova, Natalia B; Stanika, Ruslan I; Kazanina, Galina; Villanueva, Idalis; Andrews, S Brian

    2014-02-01

    Zinc has been implicated in neurodegeneration following ischemia. In analogy with calcium, zinc has been proposed to induce toxicity via mitochondrial dysfunction, but the relative role of each cation in mitochondrial damage remains unclear. Here, we report that under conditions mimicking ischemia in hippocampal neurons - normal (2 mM) calcium plus elevated (> 100 μM) exogenous zinc - mitochondrial dysfunction evoked by glutamate, kainate or direct depolarization is, despite significant zinc uptake, primarily governed by calcium. Thus, robust mitochondrial ion accumulation, swelling, depolarization, and reactive oxygen species generation were only observed after toxic stimulation in calcium-containing media. This contrasts with the lack of any mitochondrial response in zinc-containing but calcium-free medium, even though zinc uptake and toxicity were strong under these conditions. Indeed, abnormally high, ionophore-induced zinc uptake was necessary to elicit any mitochondrial depolarization. In calcium- and zinc-containing media, depolarization-induced zinc uptake facilitated cell death and enhanced accumulation of mitochondrial calcium, which localized to characteristic matrix precipitates. Some of these contained detectable amounts of zinc. Together these data indicate that zinc uptake is generally insufficient to trigger mitochondrial dysfunction, so that mechanism(s) of zinc toxicity must be different from that of calcium. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  16. Ozone-Induced Responses in Croton floribundus Spreng. (Euphorbiaceae): Metabolic Cross-Talk between Volatile Organic Compounds and Calcium Oxalate Crystal Formation

    PubMed Central

    Cardoso-Gustavson, Poliana; Bolsoni, Vanessa Palermo; de Oliveira, Debora Pinheiro; Guaratini, Maria Tereza Gromboni; Aidar, Marcos Pereira Marinho; Marabesi, Mauro Alexandre; Alves, Edenise Segala; de Souza, Silvia Ribeiro

    2014-01-01

    Here, we proposed that volatile organic compounds (VOC), specifically methyl salicylate (MeSA), mediate the formation of calcium oxalate crystals (COC) in the defence against ozone (O3) oxidative damage. We performed experiments using Croton floribundus, a pioneer tree species that is tolerant to O3 and widely distributed in the Brazilian forest. This species constitutively produces COC. We exposed plants to a controlled fumigation experiment and assessed biochemical, physiological, and morphological parameters. O3 induced a significant increase in the concentrations of constitutive oxygenated compounds, MeSA and terpenoids as well as in COC number. Our analysis supported the hypothesis that ozone-induced VOC (mainly MeSA) regulate ROS formation in a way that promotes the opening of calcium channels and the subsequent formation of COC in a fast and stable manner to stop the consequences of the reactive oxygen species in the tissue, indeed immobilising the excess calcium (caused by acute exposition to O3) that can be dangerous to the plant. To test this hypothesis, we performed an independent experiment spraying MeSA over C. floribundus plants and observed an increase in the number of COC, indicating that this compound has a potential to directly induce their formation. Thus, the tolerance of C. floribundus to O3 oxidative stress could be a consequence of a higher capacity for the production of VOC and COC rather than the modulation of antioxidant balance. We also present some insights into constitutive morphological features that may be related to the tolerance that this species exhibits to O3. PMID:25165889

  17. Association of Urinary Calcium Excretion with Serum Calcium and Vitamin D Levels

    PubMed Central

    Rathod, Anita; Bonny, Olivier; Guessous, Idris; Suter, Paolo M.; Conen, David; Erne, Paul; Binet, Isabelle; Gabutti, Luca; Gallino, Augusto; Muggli, Franco; Hayoz, Daniel; Péchère-Bertschi, Antoinette; Paccaud, Fred

    2015-01-01

    Background and objectives Population-based data on urinary calcium excretion are scarce. The association of serum calcium and circulating levels of vitamin D [25(OH)D2 or D3] with urinary calcium excretion in men and women from a population-based study was explored. Design, settings, participants, & measurements Multivariable linear regression was used to explore factors associated with square root–transformed 24-hour urinary calcium excretion (milligrams per 24 hours) taken as the dependent variable with a focus on month-specific vitamin D tertiles and serum calcium in the Swiss Survey on Salt Study. Results In total, 624 men and 669 women were studied with mean ages of 49.2 and 47.0 years, respectively (age range=15–95 years). Mean urinary calcium excretion was higher in men than in women (183.05 versus 144.60 mg/24 h; P<0.001). In adjusted models, the association (95% confidence interval) of square root urinary calcium excretion with protein–corrected serum calcium was 1.78 (95% confidence interval, 1.21 to 2.34) mg/24 h per milligram per deciliter in women and 0.59 (95% confidence interval, −0.11 to 1.29) mg/24 h per milligram per deciliter in men. Men in the third 25(OH)D3 tertile had higher square root urinary calcium excretion than men in the first tertile (0.99; 95% confidence interval, 0.36 to 1.63 mg/24 h per nanogram per milliliter), and the corresponding association was 0.32 (95% confidence interval, −0.22 to 0.85) mg/24 h per nanogram per milliliter in women. These sex differences were more marked under conditions of high urinary sodium or urea excretions. Conclusions There was a positive association of serum calcium with urinary calcium excretion in women but not men. Vitamin 25(OH)D3 was associated with urinary calcium excretion in men but not women. These results suggest important sex differences in the hormonal and dietary control of urinary calcium excretion. PMID:25518946

  18. Association of urinary calcium excretion with serum calcium and vitamin D levels.

    PubMed

    Rathod, Anita; Bonny, Olivier; Guessous, Idris; Suter, Paolo M; Conen, David; Erne, Paul; Binet, Isabelle; Gabutti, Luca; Gallino, Augusto; Muggli, Franco; Hayoz, Daniel; Péchère-Bertschi, Antoinette; Paccaud, Fred; Burnier, Michel; Bochud, Murielle

    2015-03-06

    Population-based data on urinary calcium excretion are scarce. The association of serum calcium and circulating levels of vitamin D [25(OH)D2 or D3] with urinary calcium excretion in men and women from a population-based study was explored. Multivariable linear regression was used to explore factors associated with square root-transformed 24-hour urinary calcium excretion (milligrams per 24 hours) taken as the dependent variable with a focus on month-specific vitamin D tertiles and serum calcium in the Swiss Survey on Salt Study. In total, 624 men and 669 women were studied with mean ages of 49.2 and 47.0 years, respectively (age range=15-95 years). Mean urinary calcium excretion was higher in men than in women (183.05 versus 144.60 mg/24 h; P<0.001). In adjusted models, the association (95% confidence interval) of square root urinary calcium excretion with protein-corrected serum calcium was 1.78 (95% confidence interval, 1.21 to 2.34) mg/24 h per milligram per deciliter in women and 0.59 (95% confidence interval, -0.11 to 1.29) mg/24 h per milligram per deciliter in men. Men in the third 25(OH)D3 tertile had higher square root urinary calcium excretion than men in the first tertile (0.99; 95% confidence interval, 0.36 to 1.63 mg/24 h per nanogram per milliliter), and the corresponding association was 0.32 (95% confidence interval, -0.22 to 0.85) mg/24 h per nanogram per milliliter in women. These sex differences were more marked under conditions of high urinary sodium or urea excretions. There was a positive association of serum calcium with urinary calcium excretion in women but not men. Vitamin 25(OH)D3 was associated with urinary calcium excretion in men but not women. These results suggest important sex differences in the hormonal and dietary control of urinary calcium excretion. Copyright © 2015 by the American Society of Nephrology.

  19. Calcium binding properties of calcium dependent protein kinase 1 (CaCDPK1) from Cicer arietinum.

    PubMed

    Dixit, Ajay Kumar; Jayabaskaran, Chelliah

    2015-05-01

    Calcium plays a crucial role as a secondary messenger in all aspects of plant growth, development and survival. Calcium dependent protein kinases (CDPKs) are the major calcium decoders, which couple the changes in calcium level to an appropriate physiological response. The mechanism by which calcium regulates CDPK protein is not well understood. In this study, we investigated the interactions of Ca(2+) ions with the CDPK1 isoform of Cicer arietinum (CaCDPK1) using a combination of biophysical tools. CaCDPK1 has four different EF hands as predicted by protein sequence analysis. The fluorescence emission spectrum of CaCDPK1 showed quenching with a 5 nm red shift upon addition of calcium, indicating conformational changes in the tertiary structure. The plot of changes in intensity against calcium concentrations showed a biphasic curve with binding constants of 1.29 μM and 120 μM indicating two kinds of binding sites. Isothermal calorimetric (ITC) titration with CaCl2 also showed a biphasic curve with two binding constants of 0.027 μM and 1.7 μM. Circular dichroism (CD) spectra showed two prominent peaks at 208 and 222 nm indicating that CaCDPK1 is a α-helical rich protein. Calcium binding further increased the α-helical content of CaCDPK1 from 75 to 81%. Addition of calcium to CaCDPK1 also increased fluorescence of 8-anilinonaphthalene-1-sulfonic acid (ANS) indicating exposure of hydrophobic surfaces. Thus, on the whole this study provides evidence for calcium induced conformational changes, exposure of hydrophobic surfaces and heterogeneity of EF hands in CaCDPK1. Copyright © 2015 Elsevier GmbH. All rights reserved.

  20. Skin Barrier and Calcium.

    PubMed

    Lee, Sang Eun; Lee, Seung Hun

    2018-06-01

    Epidermal barrier formation and the maintenance of barrier homeostasis are essential to protect us from the external environments and organisms. Moreover, impaired keratinocytes differentiation and dysfunctional skin barrier can be the primary causes or aggravating factors for many inflammatory skin diseases including atopic dermatitis and psoriasis. Therefore, understanding the regulation mechanisms of keratinocytes differentiation and skin barrier homeostasis is important to understand many skin diseases and establish an effective treatment strategy. Calcium ions (Ca 2+ ) and their concentration gradient in the epidermis are essential in regulating many skin functions, including keratinocyte differentiation, skin barrier formation, and permeability barrier homeostasis. Recent studies have suggested that the intracellular Ca 2+ stores such as the endoplasmic reticulum (ER) are the major components that form the epidermal calcium gradient and the ER calcium homeostasis is crucial for regulating keratinocytes differentiation, intercellular junction formation, antimicrobial barrier, and permeability barrier homeostasis. Thus, both Ca 2+ release from intracellular stores, such as the ER and Ca 2+ influx mechanisms are important in skin barrier. In addition, growing evidences identified the functional existence and the role of many types of calcium channels which mediate calcium flux in keratinocytes. In this review, the origin of epidermal calcium gradient and their role in the formation and regulation of skin barrier are focused. We also focus on the role of ER calcium homeostasis in skin barrier. Furthermore, the distribution and role of epidermal calcium channels, including transient receptor potential channels, store-operated calcium entry channel Orai1, and voltage-gated calcium channels in skin barrier are discussed.

  1. Space Flight Calcium: Implications for Astronaut Health, Spacecraft Operations, and Earth

    PubMed Central

    Smith, Scott M.; McCoy, Torin; Gazda, Daniel; Morgan, Jennifer L. L.; Heer, Martina; Zwart, Sara R.

    2012-01-01

    The space flight environment is known to induce bone loss and, subsequently, calcium loss. The longer the mission, generally the more bone and calcium are lost. This review provides a history of bone and calcium studies related to space flight and highlights issues related to calcium excretion that the space program must consider so that urine can be recycled. It also discusses a novel technique using natural stable isotopes of calcium that will be helpful in the future to determine calcium and bone balance during space flight. PMID:23250146

  2. The Function of the Mitochondrial Calcium Uniporter in Neurodegenerative Disorders

    PubMed Central

    Liao, Yajin; Dong, Yuan; Cheng, Jinbo

    2017-01-01

    The mitochondrial calcium uniporter (MCU)—a calcium uniporter on the inner membrane of mitochondria—controls the mitochondrial calcium uptake in normal and abnormal situations. Mitochondrial calcium is essential for the production of adenosine triphosphate (ATP); however, excessive calcium will induce mitochondrial dysfunction. Calcium homeostasis disruption and mitochondrial dysfunction is observed in many neurodegenerative disorders. However, the role and regulatory mechanism of the MCU in the development of these diseases are obscure. In this review, we summarize the role of the MCU in controlling oxidative stress-elevated mitochondrial calcium and its function in neurodegenerative disorders. Inhibition of the MCU signaling pathway might be a new target for the treatment of neurodegenerative disorders. PMID:28208618

  3. Effects of luteolin on regulatory proteins and enzymes for myocyte calcium circulation in hypothermic preserved rat heart

    PubMed Central

    Yan, Qingfeng; Li, Yueping; Yan, Jia; Zhao, Ying; Liu, Yunzhong; Liu, Su

    2018-01-01

    Heart transplantation has been applied in the clinic as an optimal solution for patients with end stage cardiac failure for a number of years. However, hypothermic preservation of the heart remains limited to 4–6 h and calcium accumulation over time is an important factor resulting in cell death. To provide longer and safer storage for donor hearts, it was demonstrated in our previous study that luteolin, a traditional Chinese medicine used to treat cardiovascular diseases, inhibits cell death and L-type calcium currents during hypothermic preservation. In the current study, the protective role of luteolin in modulating cardiomyocyte calcium cycling was further investigated. Intracellular calcium overload has already been implicated in hypothermia-induced dysfunction of cardiomyocytes. University of Wisconsin (UW) solution supplemented with 7.5, 15 or 30 µmol/l luteolin was used to preserve fresh isolated cardiomyocytes at 4°C. The results demonstrated that all three doses of luteolin supplementation attenuated calcium overload over a 6 h preservation period. Luteolin also suppressed the accumulation of important regulatory proteins and enzymes for cardiomyocyte calcium circulation, mitochondria Ca2+ uniporter and calmodulin, which are normally induced by cold storage in UW solution. Protein Kinase A activity was also suppressed in cardiomyocytes preserved in luteolin supplemented UW solution, while Ca2+-Mg2+-ATPase activity was increased. The results demonstrated that luteolin confers a cardioprotective effect through inhibiting the changes of calcium regulators during cold storage and therefore ameliorates Ca2+ overload in rat cardiomyocytes. PMID:29399124

  4. Hydrogen-enriched water restoration of impaired calcium propagation by arsenic in primary keratinocytes

    NASA Astrophysics Data System (ADS)

    Yu, Wei-Tai; Chiu, Yi-Ching; Lee, Chih-Hung; Yoshioka, Tohru; Yu, Hsin-Su

    2013-11-01

    Endemic contamination of artesian water for drinking by arsenic is known to cause several human cancers, including cancers of the skin, bladder, and lungs. In skin, multiple arsenic-induced Bowen's disease (As-BD) can develop into invasive cancers after decades of arsenic exposure. The characteristic histological features of As-BD include full-layer epidermal dysplasia, apoptosis, and abnormal proliferation. Calcium propagation is an essential cellular event contributing to keratinocyte differentiation, proliferation, and apoptosis, all of which occur in As-BD. This study investigated how arsenic interferes calcium propagation of skin keratinocytes through ROS production and whether hydrogen-enriched water would restore arsenic-impaired calcium propagation. Arsenic was found to induce oxidative stress and inhibit ATP- and thapsigaragin-induced calcium propagation. Pretreatment of arsenic-treated keratinocytes by hydrogen-enriched water or beta-mercaptoethanol with potent anti-oxidative effects partially restored the propagation of calcium by ATP and by thapsigaragin. It was concluded that arsenic may impair calcium propagation, likely through oxidative stress and interactions with thiol groups in membrane proteins.

  5. Calcium and α-tocopherol suppress cured-meat promotion of chemically induced colon carcinogenesis in rats and reduce associated biomarkers in human volunteers123

    PubMed Central

    Martin, Océane CB; Santarelli, Raphaelle L; Taché, Sylviane; Naud, Nathalie; Guéraud, Françoise; Audebert, Marc; Dupuy, Jacques; Meunier, Nathalie; Attaix, Didier; Vendeuvre, Jean-Luc; Mirvish, Sidney S; Kuhnle, Gunter CG; Cano, Noel; Corpet, Denis E

    2013-01-01

    Background: Processed meat intake has been associated with increased colorectal cancer risk. We have shown that cured meat promotes carcinogen-induced preneoplastic lesions and increases specific biomarkers in the colon of rats. Objectives: We investigated whether cured meat modulates biomarkers of cancer risk in human volunteers and whether specific agents can suppress cured meat–induced preneoplastic lesions in rats and associated biomarkers in rats and humans. Design: Six additives (calcium carbonate, inulin, rutin, carnosol, α-tocopherol, and trisodium pyrophosphate) were added to cured meat given to groups of rats for 14 d, and fecal biomarkers were measured. On the basis of these results, calcium and tocopherol were kept for the following additional experiments: cured meat, with or without calcium or tocopherol, was given to dimethylhydrazine-initiated rats (47% meat diet for 100 d) and to human volunteers in a crossover study (180 g/d for 4 d). Rat colons were scored for mucin-depleted foci, putative precancer lesions. Biomarkers of nitrosation, lipoperoxidation, and cytotoxicity were measured in the urine and feces of rats and volunteers. Results: Cured meat increased nitroso compounds and lipoperoxidation in human stools (both P < 0.05). Calcium normalized both biomarkers in rats and human feces, whereas tocopherol only decreased nitro compounds in rats and lipoperoxidation in feces of volunteers (all P < 0.05). Last, calcium and tocopherol reduced the number of mucin-depleted foci per colon in rats compared with nonsupplemented cured meat (P = 0.01). Conclusion: Data suggest that the addition of calcium carbonate to the diet or α-tocopherol to cured meat may reduce colorectal cancer risk associated with cured-meat intake. This trial was registered at clinicaltrials.gov as NCT00994526. PMID:24025632

  6. Exopolysaccharides regulate calcium flow in cariogenic biofilms

    PubMed Central

    Varenganayil, Muth M.; Decho, Alan W.

    2017-01-01

    Caries-associated biofilms induce loss of calcium from tooth surfaces in the presence of dietary carbohydrates. Exopolysaccharides (EPS) provide a matrix scaffold and an abundance of primary binding sites within biofilms. The role of EPS in binding calcium in cariogenic biofilms is only partially understood. Thus, the aim of the present study is to investigate the relationship between the calcium dissolution rates and calcium tolerance of caries-associated bacteria and yeast as well as to examine the properties of EPS to quantify its binding affinity for dissolved calcium. Calcium dissolution was measured by dissolution zones on Pikovskaya’s agar. Calcium tolerance was assessed by isothermal microcalorimetry (IMC) by adding CaCl2 to the bacterial cultures. Acid-base titration and Fourier transform infrared (FTIR) spectroscopy were used to identify possible functional groups responsible for calcium binding, which was assessed by isothermal titration calorimetry (ITC). Lactobacillus spp. and mutans streptococci demonstrated calcium dissolution in the presence of different carbohydrates. All strains that demonstrated high dissolution rates also revealed higher rates of calcium tolerance by IMC. In addition, acidic functional groups were predominantly identified as possible binding sites for calcium ions by acid-base titration and FTIR. Finally, ITC revealed EPS to have a higher binding affinity for calcium compared, for example, to lactic acid. In conclusion, this study illustrates the role of EPS in terms of the calcium tolerance of cariogenic microbiota by determining the ability of EPS to control free calcium concentrations within the biofilms as a self-regulating mode of action in the pathogenesis of dental caries. PMID:29023506

  7. Acidosis and Urinary Calcium Excretion: Insights from Genetic Disorders

    PubMed Central

    Cordat, Emmanuelle; Chambrey, Régine; Dimke, Henrik; Eladari, Dominique

    2016-01-01

    Metabolic acidosis is associated with increased urinary calcium excretion and related sequelae, including nephrocalcinosis and nephrolithiasis. The increased urinary calcium excretion induced by metabolic acidosis predominantly results from increased mobilization of calcium out of bone and inhibition of calcium transport processes within the renal tubule. The mechanisms whereby acid alters the integrity and stability of bone have been examined extensively in the published literature. Here, after briefly reviewing this literature, we consider the effects of acid on calcium transport in the renal tubule and then discuss why not all gene defects that cause renal tubular acidosis are associated with hypercalciuria and nephrocalcinosis. PMID:27468975

  8. Modulation of CaV2.1 channels by neuronal calcium sensor-1 induces short-term synaptic facilitation.

    PubMed

    Yan, Jin; Leal, Karina; Magupalli, Venkat G; Nanou, Evanthia; Martinez, Gilbert Q; Scheuer, Todd; Catterall, William A

    2014-11-01

    Facilitation and inactivation of P/Q-type Ca2+ currents mediated by Ca2+/calmodulin binding to Ca(V)2.1 channels contribute to facilitation and rapid depression of synaptic transmission, respectively. Other calcium sensor proteins displace calmodulin from its binding site and differentially modulate P/Q-type Ca2 + currents, resulting in diverse patterns of short-term synaptic plasticity. Neuronal calcium sensor-1 (NCS-1, frequenin) has been shown to enhance synaptic facilitation, but the underlying mechanism is unclear. We report here that NCS-1 directly interacts with IQ-like motif and calmodulin-binding domain in the C-terminal domain of Ca(V)2.1 channel. NCS-1 reduces Ca2 +-dependent inactivation of P/Q-type Ca2+ current through interaction with the IQ-like motif and calmodulin-binding domain without affecting peak current or activation kinetics. Expression of NCS-1 in presynaptic superior cervical ganglion neurons has no effect on synaptic transmission, eliminating effects of this calcium sensor protein on endogenous N-type Ca2+ currents and the endogenous neurotransmitter release machinery. However, in superior cervical ganglion neurons expressing wild-type Ca(V)2.1 channels, co-expression of NCS-1 induces facilitation of synaptic transmission in response to paired pulses and trains of depolarizing stimuli, and this effect is lost in Ca(V)2.1 channels with mutations in the IQ-like motif and calmodulin-binding domain. These results reveal that NCS-1 directly modulates Ca(V)2.1 channels to induce short-term synaptic facilitation and further demonstrate that CaS proteins are crucial in fine-tuning short-term synaptic plasticity.

  9. Coronary calcium in systemic lupus erythematosus is associated with traditional cardiovascular risk factors, but not with disease activity.

    PubMed

    Kiani, Adnan N; Magder, Laurence; Petri, Michelle

    2008-07-01

    Cardiovascular disease is a major cause of morbidity and mortality in systemic lupus erythematosus (SLE). The frequency of both subclinical and clinically evident atherosclerosis is greatly increased over healthy controls. We assessed cardiovascular risk factors present in patients with SLE at the baseline visit in a statin intervention trial and their correlation with coronary calcium. Coronary calcium was measured by helical computed tomography (continuous volumetric data acquisition in a single breath-hold) in 200 patients with SLE enrolled in the Lupus Atherosclerosis Prevention Study. Patients had a mean age of 44.3 +/- 11.4 years and were 92% women, 61% Caucasian, 34% African American, 2% Asian, and 2% Hispanic. Coronary calcium was found in 43%. In univariate analysis, coronary calcification was associated with age (p = 0.0001), hypertension (p = 0.0008), body mass index (BMI; p = 0.03), erythrocyte sedimentation rate (ESR; p = 0.03), anti-dsDNA (p = 0.067), and lipoprotein(a) (p = 0.03). Homocysteine (p = 0.050), high-sensitivity C-reactive protein (hsCRP; p = 0.053), and LDL (p = 0.048) had a stronger association when considered as quantitative predictors. In a multiple logistic regression model, only age (p calcium. We also examined variables independently predictive of a coronary calcium score > 100. Based on a multiple logistic regression model, only age (p = 0.0017) and diabetes mellitus (p = 0.019) remained significant independent predictors of coronary calcium > 100. Inflammation, measured as ESR or hsCRP, is associated with coronary calcium only in univariate analyses. Age, BMI, and diabetes mellitus are more important associates of coronary calcium in SLE than inflammatory markers and SLE clinical activity.

  10. The effect of ascorbic acid ingestion on the biochemical and physicochemical risk factors associated with calcium oxalate kidney stone formation.

    PubMed

    Auer, B L; Auer, D; Rodgers, A L

    1998-03-01

    The present study was undertaken to determine the effect of ingestion of large doses of vitamin C on urinary oxalate excretion and on a number of other biochemical and physicochemical risk factors associated with calcium oxalate urolithiasis. A further objective was to determine urinary ascorbate excretion and to relate it qualitatively to ingested levels of the vitamin and oxalate excretion. Ten healthy males participated in a protocol in which 4 g ascorbic acid was ingested for 5 days. Urines (24 h) were collected prior to, during and after the protocol. The urine collection procedure was designed to allow for the analysis of oxalate in the presence and absence of an EDTA preservative and for the analysis of ascorbic acid by manual titration using 2,6 dichlorophenolindophenol. Physicochemical risk factors such as the calcium oxalate relative supersaturation and Tiselius risk index were calculated from urine composition. The results showed that erroneously high analytical oxalate levels occur in the asence of preservative. In the preserved samples there was no significant increase in oxalate excretion at any stage of the protocol. Ascorbate excretion increased when vitamin C ingestion commenced but levelled out after 24 hours suggesting that saturation of the metabolic pool is reached within 24 hours after which ingested ascorbic acid is excreted unmetabolized in the urine. While transient statistically significant changes occurred in some of the biochemical risk factors, they were not regarded as being clinically significant. There were no changes in either the calcium oxalate relative supersaturation or Tiselius risk index. It is concluded that ingestion of large doses of ascorbic acid does not affect the principal risk factors associated with calcium oxalate kidney stone formation.

  11. T-type calcium channel antagonism decreases motivation for nicotine and blocks nicotine- and cue-induced reinstatement for a response previously reinforced with nicotine.

    PubMed

    Uslaner, Jason M; Vardigan, Joshua D; Drott, Jason M; Uebele, Victor N; Renger, John J; Lee, Ariel; Li, Zhaoxia; Lê, A D; Hutson, Pete H

    2010-10-15

    Recent evidence suggests an involvement of T-type calcium channels in the effects of drugs of abuse. We examined the influence of the novel, potent, and selective T-type calcium channel antagonist [2-(4-cyclopropylphenyl)-N-((1R)-1-{5-[2,2,2-trifluoroethyl]oxo}pyridine-2-yl)ethyl]acetamide] (TTA-A2) (.3, 1, or 3 mg/kg) on motivation for nicotine, as measured by nicotine self-administration on a progressive ratio (PR) schedule, and nicotine- and cue-induced reinstatement for a response previously reinforced with nicotine delivery (n = 11 or 12 Long Evans rats/group). Furthermore, we examined the specificity of the TTA-A2 effects by characterizing its influence on PR responding for food (in the absence or presence of nicotine-potentiated responding), food- versus nicotine-induced cue-potentiated reinstatement for a response previously reinforced by food administration (n = 11 or 12 Wistar Hannover rats/group), and its ability to induce a conditioned place aversion. TTA-A2 dose-dependently decreased self-administration of nicotine on a PR schedule and the ability of both nicotine and a cue paired with nicotine to reinstate responding. The effects were specific for nicotine's incentive motivational properties, as TTA-A2 did not influence responding for food on a PR schedule but did attenuate the ability of nicotine to potentiate responding for food. Likewise, TTA-A2 did not alter food-induced cue-potentiated reinstatement for a response previously reinforced by food but did decrease nicotine-induced cue-potentiated reinstatement. Finally, TTA-A2 did not produce an aversive state, as indicated by a lack of ability to induce conditioned place aversion. These data suggest that T-type calcium channel antagonists have potential for alleviating nicotine addiction by selectively decreasing the incentive motivational properties of nicotine. Copyright © 2010 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  12. Rhesus rotavirus VP6 regulates ERK-dependent calcium influx in cholangiocytes.

    PubMed

    Lobeck, Inna; Donnelly, Bryan; Dupree, Phylicia; Mahe, Maxime M; McNeal, Monica; Mohanty, Sujit K; Tiao, Greg

    2016-12-01

    The Rhesus rotavirus (RRV) induced murine model of biliary atresia (BA) is a useful tool in studying the pathogenesis of this neonatal biliary obstructive disease. In this model, the mitogen associated protein kinase pathway is involved in RRV infection of biliary epithelial cells (cholangiocytes). We hypothesized that extracellular signal-related kinase (ERK) phosphorylation is integral to calcium influx, allowing for viral replication within the cholangiocyte. Utilizing ERK and calcium inhibitors in immortalized cholangiocytes and BALB/c pups, we determined that ERK inhibition resulted in reduced viral yield and subsequent decreased symptomatology in mice. In vitro, the RRV VP6 protein induced ERK phosphorylation, leading to cellular calcium influx. Pre-treatment with an ERK inhibitor or Verapamil resulted in lower viral yields. We conclude that the pathogenesis of RRV-induced murine BA is dependent on the VP6 protein causing ERK phosphorylation and triggering calcium influx allowing replication in cholangiocytes. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Effects of calcium dobesilate on Nrf2, Keap1 and HO-1 in the lenses of D-galactose-induced cataracts in rats

    PubMed Central

    Sun, Jinfeng; Wang, Bin; Hao, Youjuan; Yang, Xueli

    2018-01-01

    This study investigated the effects of calcium dobesilate on Nrf2, Keap1 and HO-1 in the lenses of D-galactose-induced cataracts in rats. Thirty Sprague-Dawley rats were randomly divided into three groups: a blank control group, a model control group and a model administration group. A normal diet was given to the rats in the blank control group and the rats with D-galactose-induced cataracts of the model control group. Calcium dobesilate was also given to the rats with D-galactose-induced cataracts of the model administration group. A slit lamp microscope was used to check the degree of lens opacity. RT-PCR and western blot analysis were used to detect the mRNA and protein expression of Nrf2, Keap1 and HO-1 in the lenses of the three groups. There was a significant difference in the degree of lens opacity among the three groups (P<0.05). The model control group was the most turbid of the three groups, followed by the model administration group. Moreover, the mRNA and protein expression of Nrf2, Keap1 and HO-1 in the lenses of the three groups were also significantly different (P<0.05). The mRNA levels of Nrf2 and HO-1 were the highest in the model control group, followed by the model administration group, and were the lowest in the blank control group. However, the mRNA expression level of Keap1 among the three groups had an opposite trend. In conclusion, calcium dobesilate can effectively increase the levels of Nrf2 and HO-1 in the lenses of diabetic cataract rats and inhibit the level of Keap1. Therefore, the therapeutic effect of calcium dobesilate against cataracts is related to the improvement of the Nrf2-Keap1 signaling pathway. PMID:29399076

  14. Dietary protein, calcium metabolism, and skeletal homeostasis revisited.

    PubMed

    Kerstetter, Jane E; O'Brien, Kimberly O; Insogna, Karl L

    2003-09-01

    High dietary protein intakes are known to increase urinary calcium excretion and, if maintained, will result in sustained hypercalciuria. To date, the majority of calcium balance studies in humans have not detected an effect of dietary protein on intestinal calcium absorption or serum parathyroid hormone. Therefore, it is commonly concluded that the source of the excess urinary calcium is increased bone resorption. Recent studies from our laboratory indicate that alterations in dietary protein can, in fact, profoundly affect intestinal calcium absorption. In short-term dietary trials in healthy adults, we fixed calcium intake at 20 mmol/d while dietary protein was increased from 0.7 to 2.1 g/kg. Increasing dietary protein induced hypercalciuria in 20 women [from 3.4 +/- 0.3 ( +/- SE) during the low-protein to 5.4 +/- 0.4 mmol/d during the high-protein diet]. The increased dietary protein was accompanied by a significant increase in intestinal calcium absorption from 18.4 +/- 1.3% to 26.3 +/- 1.5% (as determined by dual stable isotopic methodology). Dietary protein intakes at and below 0.8 g/kg were associated with a probable reduction in intestinal calcium absorption sufficient to cause secondary hyperparathyroidism. The long-term consequences of these low-protein diet-induced changes in mineral metabolism are not known, but the diet could be detrimental to skeletal health. Of concern are several recent epidemiologic studies that demonstrate reduced bone density and increased rates of bone loss in individuals habitually consuming low-protein diets. Studies are needed to determine whether low protein intakes directly affect rates of bone resorption, bone formation, or both.

  15. Multiparameter imaging of calcium and abscisic acid and high-resolution quantitative calcium measurements using R-GECO1-mTurquoise in Arabidopsis.

    PubMed

    Waadt, Rainer; Krebs, Melanie; Kudla, Jörg; Schumacher, Karin

    2017-10-01

    Calcium signals occur in specific spatio-temporal patterns in response to various stimuli and are coordinated with, for example, hormonal signals, for physiological and developmental adaptations. Quantification of calcium together with other signalling molecules is required for correlative analyses and to decipher downstream calcium-decoding mechanisms. Simultaneous in vivo imaging of calcium and abscisic acid has been performed here to investigate the interdependence of the respective signalling processes in Arabidopsis thaliana roots. Advanced ratiometric genetically encoded calcium indicators have been generated and in vivo calcium calibration protocols were established to determine absolute calcium concentration changes in response to auxin and ATP. In roots, abscisic acid induced long-term basal calcium concentration increases, while auxin triggered rapid signals in the elongation zone. The advanced ratiometric calcium indicator R-GECO1-mTurquoise exhibited an increased calcium signal resolution compared to commonly used Förster resonance energy transfer-based indicators. Quantitative calcium measurements in Arabidopsis root tips using R-GECO1-mTurquoise revealed detailed maps of absolute calcium concentration changes in response to auxin and ATP. Calcium calibration protocols using R-GECO1-mTurquoise enabled high-resolution quantitative imaging of resting cytosolic calcium concentrations and their dynamic changes that revealed distinct hormonal and ATP responses in roots. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  16. Calcium Channels, Rho-Kinase, Protein Kinase-C, and Phospholipase-C Pathways Mediate Mercury Chloride-Induced Myometrial Contractions in Rats.

    PubMed

    Koli, Swati; Prakash, Atul; Choudhury, Soumen; Mandil, Rajesh; Garg, Satish K

    2018-05-21

    Adverse effects of mercury on female reproduction are reported; however, its effect on myogenic activity of uterus and mechanism thereof is obscure. Present study was undertaken to unravel the mechanistic pathways of mercuric chloride (HgCl 2 )-induced myometrial contraction in rats. Isometric tension in myometrial strips of rats following in vitro exposure to HgCl 2 was recorded using data acquisition system-based physiograph. HgCl 2 produced concentration-dependent (10 nM-100 μM) uterotonic effect which was significantly (p < 0.05) reduced in Ca 2+ -free solution and inhibited in the presence of nifedipine (1 μM), a L-type Ca 2+ channel blocker, thus suggesting the importance of extracellular Ca 2+ and its entry through L-type calcium channels in HgCl 2 -induced myometrial contractions in rats. Cumulative concentration-response curve of HgCl 2 was significantly (p < 0.05) shifted towards right in the presence of Y-27632 (10 μM), a Rho-kinase inhibitor, suggesting the involvement of Ca 2+ -sensitization pathway in mediating HgCl 2 -induced myometrial contraction. HgCl 2 -induced myometrial contraction was also significantly (p < 0.05) inhibited in the presence of methoctramine or para-fluoro-hexahydro-siladifenidol, a selective M 2 and M 3 receptor antagonists, respectively, which evidently suggest that mercury also interacts with M 2 and M 3 muscarinic receptors to produce myometrial contractions. U-73122 and GF-109203X, the respective inhibitors of PLC and PKC-dependent pathways, downstream to the receptor activation, also significantly (p < 0.05) attenuated the uterotonic effect of HgCl 2 on rat uterus. Taken together, present study evidently reveals that HgCl 2 interacts with muscarinic receptors and activates calcium signaling cascades involving calcium channels, Rho-kinase, protein kinase-C, and phospholipase-C pathways to exert uterotonic effect in rats. Graphical Abstract Graphical abstract depicting the mechanism of mercury-induced

  17. Letrozole induced low estrogen levels affected the expressions of duodenal and renal calcium-processing gene in laying hens.

    PubMed

    Li, Qiao; Zhao, Xingkai; Wang, Shujie; Zhou, Zhenlei

    2018-01-01

    Estrogen regulates the calcium homeostasis in hens, but the mechanisms involved are still unclear fully. In this study, we investigated whether letrozole (LZ) induced low estrogen levels affected the calcium absorption and transport in layers. In the duodenum, we observed a significant decrease of mRNA expressions of Calbindin-28k (CaBP-28k) and plasma membrane Ca 2+ -ATPase (PMCA 1b) while CaBP-28k protein expression was declined in birds with LZ treatment, and the mRNA levels of duodenal transient receptor potential vanilloid 6 (TRPV6) and Na + /Ca 2+ exchanger 1 (NCX1) were not affected. Interestingly, we observed the different changes in the kidney. The renal mRNA expressions of TRPV6 and NCX1 were unregulated while the PMCA1b was down-regulated in low estrogen layers, however, the CaBP-28k gene and protein expressions were no changed in the kidney. Furthermore, it showed that the duodenal estradiol receptor 2 (ESR2) transcripts rather than parathyroid hormone 1 receptor (PTH1R) and calcitonin receptor (CALCR) played key roles to down-regulate calcium transport in LZ-treated birds. In conclusion, CaBP-28k, PMCA 1b and ESR2 genes in the duodenum may be primary targets for estrogen regulation in order to control calcium homeostasis in hens. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Bacterially induced mineralization of calcium carbonate: the role of exopolysaccharides and capsular polysaccharides.

    PubMed

    Ercole, Claudia; Cacchio, Paola; Botta, Anna Lucia; Centi, Valeria; Lepidi, Aldo

    2007-02-01

    Bacterially induced carbonate mineralization has been proposed as a new method for the restoration of limestones in historic buildings and monuments. We describe here the formation of calcite crystals by extracellular polymeric substances isolated from Bacillus firmus and Bacillus sphaericus. We isolated bacterial outer structures (glycocalix and parietal polymers), such as exopolysaccharides (EPS) and capsular polysaccharides (CPS) and checked for their influence on calcite precipitation. CPS and EPS extracted from both B. firmus and B. sphaericus were able to mediate CaCO3 precipitation in vitro. X-ray microanalysis showed that in all cases the formed crystals were calcite. Scanning electron microscopy showed that the shape of the crystals depended on the fractions utilized. These results suggest the possibility that biochemical composition of CPS or EPS influences the resulting morphology of CaCO3. There were no precipitates in the blank samples. CPS and EPS comprised of proteins and glycoproteins. Positive alcian blue staining also reveals acidic polysaccharides in CPS and EPS fractions. Proteins with molecular masses of 25-40 kDa and 70 kDa in the CPS fraction were highly expressed in the presence of calcium oxalate. This high level of synthesis could be related to the binding of calcium ions and carbonate deposition.

  19. Effects of soaking and acidification on physicochemical properties of calcium-fortified rice.

    PubMed

    Sirisoontaralak, Porntip; Limboon, Pailin; Jatuwong, Sujitra; Chavanalikit, Arusa

    2016-06-01

    Calcium-fortified rice was prepared by soaking milled rice in calcium lactate solution, steaming and drying, and physicochemical properties were determined to evaluate effects of calcium concentration (0, 30, 50 g L(-1) ), soaking temperature (ambient temperature, 40 °C, 60 °C) and acidification. Calcium-fortified rice had less lightness. More total solid loss was observed, especially at high soaking temperature. Harder texture was detected with increased calcium concentration. Calcium fortification lowered pasting viscosity of milled rice. Panelists accepted all fortified rice; however, only rice soaked at 50 g L(-1) concentration could be claimed as a good source of calcium. Increasing of soaking temperature induced more penetration of calcium to rice kernels but calcium was lost more easily after washing. With addition of acetic acid to the soaking solution, enriched calcium content was comparable to that of high soaking temperature but with better retention after washing and calcium solubility was improved. Acid induced reduction of lightness and cooked rice hardness but increased total solid loss and pasting viscosity. Although the taste of acetic acid remained, panelists still accepted the fortified rice. Calcium-fortified rice (190.47-194.3 mg 100 g(-1) ) could be successfully produced by soaking milled rice in 50 g L(-1) calcium lactate solution at 40 °C or at ambient temperature with acidification. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  20. Calcium supplementation prevents endothelial cell activation: possible relevance to preeclampsia.

    PubMed

    Chen, Qi; Tong, Mancy; Wu, Man; Stone, Peter R; Snowise, Saul; Chamley, Lawrence W

    2013-09-01

    Preeclampsia is a leading cause of maternal and fetal mortality and morbidity. A hallmark of preeclampsia is endothelial cell dysfunction/activation in response to 'toxins' from the placenta. Necrotic trophoblastic debris (NTD) is one possible placental toxin and other activators of endothelial cells include inflammatory cytokines. Calcium supplementation appears to protect 'at-risk' women from developing preeclampsia but how is unclear. Placental explants were cultured with interleukin-6 (IL-6) in varied concentrations of calcium. The resultant trophoblastic debris was exposed to endothelial cells. Endothelial cells were exposed to activators including NTD, IL-6, and preeclamptic sera in the presence of varied concentrations of calcium and activation monitored by quantifying cell surface markers by ELISA. Raising the levels of calcium did not prevent the IL-6-induced shedding of NTD from placental explants but did prevent the activation of endothelial cells in response to IL-6, preeclamptic sera, or NTD. Reducing the level of calcium directly induced the activation of endothelial cells. Inhibiting nitric oxide synthetase ablated the ability of high calcium levels to protect endothelial cell activation. The activity of endothelial cell nitric oxide synthetase was blocked with L-N-nitroarginine methyl ester. Our results demonstrate calcium levels do not affect the shedding of trophoblastic debris but are important to endothelial cell activation and supplemental calcium may reverse the activation of the endothelium in preeclamptic women. These results may in part explain the benefits of calcium supplementation in the reduction of risk for developing preeclampsia and provide in-vitro mechanistic support for the use of calcium supplementation in at-risk women.

  1. A review on the kinetics of microbially induced calcium carbonate precipitation by urea hydrolysis

    NASA Astrophysics Data System (ADS)

    van Paassen, L. A.

    2017-12-01

    In this study the kinetics of calcium carbonate precipitation induced by the ureolytic bacteria are reviewed based on experiments and mathematical modelling. The study shows how urea hydrolysis rate depends on the amount of bacteria and the conditions during growth, storage, hydrolysis and precipitation. The dynamics of Microbially Induced Carbonate Precipitation has been monitored in non-seeded liquid batch experiments. Results show that particulary for a fast hydrolysis of urea (>1 M-urea day-1) in a highly concentrated equimolar solution with calcium chloride (>0.25 M) the solubility product of CaCO3 is exceeded within a short period (less than 30 minutes), the supersaturation remains high for an exended period, resulting in prolonged periods of nucleation and crystal growth and extended growth of metastable precursor mineral phases. The pH, being a result of the speciation, quickly rises until critical supersaturation is reached and precipitation is initiated. Then pH drops (sometimes showing oscillating behaviour) to about neutral where it stays until all substrates are depleted. Higher hydrolysis rates lead to higher supersaturation and pH and relatively many small crystals, whereas higher concentrations of urea and calcium chloride mainly lead to lower pH values. The conversion can be reasonably monitored by electrical conductivity and reasonably predicted, using a simplified model based on a single reaction as long as the urea hydrolysis rate is known. Complex geochemical models, which include chemical speciciation through acid-base equilibria and kinetic equations to describe mineral precipitation, do not show significant difference from the simplified model regarding the bulk chemistry and the total amount of precipitates. However, experiments show that ureolytic MICP can result in a highly variable crystal morphologies with large variation in the affected hydraulic properties when applied in a porous medium. In order to calculate the number, size and

  2. Exogenous polyamines elicit herbivore-induced volatiles in lima bean leaves: involvement of calcium, H2O2 and Jasmonic acid.

    PubMed

    Ozawa, Rika; Bertea, Cinzia M; Foti, Maria; Narayana, Ravishankar; Arimura, Gen-Ichiro; Muroi, Atsushi; Horiuchi, Jun-Ichiro; Nishioka, Takaaki; Maffei, Massimo E; Takabayashi, Junji

    2009-12-01

    We investigated the role of polyamines (PAs) in lima bean (Phaseolus lunatus) leaves on the production of herbivorous mite (Tetranychus urticae)-induced plant volatiles that attract carnivorous natural enemies of the herbivores. To do this, we focused on the effects of the exogenous PAs [cadaverine, putrescine, spermidine and spermine (Spm)] on the production of volatiles, H(2)O(2) and jasmonic acid (JA) and the levels of defensive genes, cytosolic calcium and reactive oxygen species (ROS). Among the tested PAs, Spm was the most active in inducing the production of volatile terpenoids known to be induced by T. urticae. An increase in JA levels was also found after Spm treatment, indicating that Spm induces the biosynthesis of JA, which has been shown elsewhere to regulate the production of some volatile terpenoids. Further, treatment with JA and Spm together resulted in greater volatile emission than that with JA alone. In a Y-tube olfactometer, leaves treated with Spm + JA attracted more predatory mites (Phytoseiulus persimilis) than those treated with JA alone. After treatment with Spm + JA, no effects were found on the enzyme activity of polyamine oxidase and copper amine oxidase. However, induction of calcium influx and ROS production, and increased enzyme activities and gene expression for NADPH oxidase complex, superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase and glutathione peroxidase were found after treatment with Spm + JA. These results indicate that Spm plays an important role in the production of T. urticae-induced lima bean leaf volatiles.

  3. Activation of L-type calcium channels is required for gap junction-mediated intercellular calcium signaling in osteoblastic cells

    NASA Technical Reports Server (NTRS)

    Jorgensen, Niklas Rye; Teilmann, Stefan Cuoni; Henriksen, Zanne; Civitelli, Roberto; Sorensen, Ole Helmer; Steinberg, Thomas H.

    2003-01-01

    The propagation of mechanically induced intercellular calcium waves (ICW) among osteoblastic cells occurs both by activation of P2Y (purinergic) receptors by extracellular nucleotides, resulting in "fast" ICW, and by gap junctional communication in cells that express connexin43 (Cx43), resulting in "slow" ICW. Human osteoblastic cells transmit intercellular calcium signals by both of these mechanisms. In the current studies we have examined the mechanism of slow gap junction-dependent ICW in osteoblastic cells. In ROS rat osteoblastic cells, gap junction-dependent ICW were inhibited by removal of extracellular calcium, plasma membrane depolarization by high extracellular potassium, and the L-type voltage-operated calcium channel inhibitor, nifedipine. In contrast, all these treatments enhanced the spread of P2 receptor-mediated ICW in UMR rat osteoblastic cells. Using UMR cells transfected to express Cx43 (UMR/Cx43) we confirmed that nifedipine sensitivity of ICW required Cx43 expression. In human osteoblastic cells, gap junction-dependent ICW also required activation of L-type calcium channels and influx of extracellular calcium.

  4. Tumour necrosis factor α secretion induces protease activation and acinar cell necrosis in acute experimental pancreatitis in mice.

    PubMed

    Sendler, Matthias; Dummer, Annegret; Weiss, Frank U; Krüger, Burkhard; Wartmann, Thomas; Scharffetter-Kochanek, Karin; van Rooijen, Nico; Malla, Sudarshan Ravi; Aghdassi, Ali; Halangk, Walter; Lerch, Markus M; Mayerle, Julia

    2013-03-01

    Acute pancreatitis has long been considered a disorder of pancreatic self-digestion, in which intracellular activation of digestive proteases induces tissue injury. Chemokines, released from damaged pancreatic cells then attract inflammatory cells, whose systemic action ultimately determines the disease severity. In the present work the opposite mechanism is investigated; that is, whether and how inflammatory cells can activate intracellular proteases. Using mice either deficient for the CD18-α subunit of the membrane attack complex-1 (MAC-1) complex or tumour necrosis factor (TNF)α, as well as after depletion of leucocyte subpopulations, pancreatitis was induced by 7-hourly caerulein injections (50 μg/kg, intraperitoneally). Pancreatic acini were coincubated in vitro from wild-type and cathepsin-B-deficient animals with phorbol-12-myristate-13-acetate (PMA)-activated neutrophils and macrophages, caerulein or TNFα, and activities of trypsin, cathepsin-B and caspase-3 were measured, as well as necrosis using fluorogenic substrates. TNFα was inhibited with monospecific antibodies. Deletion of CD18 prevented transmigration of leucocytes into the pancreas during pancreatitis, greatly reduced disease severity and abolished digestive protease activation. Depletion of neutrophils and macrophages equally reduced premature trypsinogen activation and disease severity. In vitro activated neutrophils and macrophages directly induced premature protease activation and cell death in pancreatic acini and stimulation of acini with TNFα induced caspase-3 activation and necrosis via a cathepsin-B and calcium-dependent mechanism. Neutralising antibodies against TNFα and genetic deletion of TNFα prevented leucocyte-induced trypsin activity and necrosis in isolated acini. The soluble inflammatory cell mediator TNFα directly induces premature protease activation and necrosis in pancreatic acinar cells. This activation depends on calcium and cathepsin-B activity. The findings

  5. Calcium Pumps and Interacting BON1 Protein Modulate Calcium Signature, Stomatal Closure, and Plant Immunity1[OPEN

    PubMed Central

    Bao, Yongmei; Yang, Ziyuan; Yu, Huiyun; Li, Yun; Wang, Shu; Zou, Baohong; Xu, Dachao; Ma, Zhiqi

    2017-01-01

    Calcium signaling is essential for environmental responses including immune responses. Here, we provide evidence that the evolutionarily conserved protein BONZAI1 (BON1) functions together with autoinhibited calcium ATPase10 (ACA10) and ACA8 to regulate calcium signals in Arabidopsis. BON1 is a plasma membrane localized protein that negatively regulates the expression of immune receptor genes and positively regulates stomatal closure. We found that BON1 interacts with the autoinhibitory domains of ACA10 and ACA8, and the aca10 loss-of-function (LOF) mutants have an autoimmune phenotype similar to that of the bon1 LOF mutants. Genetic evidences indicate that BON1 positively regulates the activities of ACA10 and ACA8. Consistent with this idea, the steady level of calcium concentration is increased in both aca10 and bon1 mutants. Most strikingly, cytosolic calcium oscillation imposed by external calcium treatment was altered in aca10, aca8, and bon1 mutants in guard cells. In addition, calcium- and pathogen-induced stomatal closure was compromised in the aca10 and bon1 mutants. Taken together, this study indicates that ACA10/8 and BON1 physically interact on plasma membrane and function in the generation of cytosol calcium signatures that are critical for stomatal movement and impact plant immunity. PMID:28701352

  6. Dehydration-induced amorphous phases of calcium carbonate.

    PubMed

    Saharay, Moumita; Yazaydin, A Ozgur; Kirkpatrick, R James

    2013-03-28

    Amorphous calcium carbonate (ACC) is a critical transient phase in the inorganic precipitation of CaCO3 and in biomineralization. The calcium carbonate crystallization pathway is thought to involve dehydration of more hydrated ACC to less hydrated ACC followed by the formation of anhydrous ACC. We present here computational studies of the transition of a hydrated ACC with a H2O/CaCO3 ratio of 1.0 to anhydrous ACC. During dehydration, ACC undergoes reorganization to a more ordered structure with a significant increase in density. The computed density of anhydrous ACC is similar to that of calcite, the stable crystalline phase. Compared to the crystalline CaCO3 phases, calcite, vaterite, and aragonite, the computed local structure of anhydrous ACC is most-similar to those of calcite and vaterite, but the overall structure is not well described by either. The strong hydrogen bond interaction between the carbonate ions and water molecules plays a crucial role in stabilizing the less hydrated ACC compositions compared to the more hydrated ones, leading to a progressively increasing hydration energy with decreasing water content.

  7. The tobacco-specific carcinogen-operated calcium channel promotes lung tumorigenesis via IGF2 exocytosis in lung epithelial cells

    PubMed Central

    Boo, Hye-Jin; Min, Hye-Young; Jang, Hyun-Ji; Yun, Hye Jeong; Smith, John Kendal; Jin, Quanri; Lee, Hyo-Jong; Liu, Diane; Kweon, Hee-Seok; Behrens, Carmen; Lee, J. Jack; Wistuba, Ignacio I.; Lee, Euni; Hong, Waun Ki; Lee, Ho-Young

    2016-01-01

    Nicotinic acetylcholine receptors (nAChRs) binding to the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) induces Ca2+ signalling, a mechanism that is implicated in various human cancers. In this study, we investigated the role of NNK-mediated Ca2+ signalling in lung cancer formation. We show significant overexpression of insulin-like growth factors (IGFs) in association with IGF-1R activation in human preneoplastic lung lesions in smokers. NNK induces voltage-dependent calcium channel (VDCC)-intervened calcium influx in airway epithelial cells, resulting in a rapid IGF2 secretion via the regulated pathway and thus IGF-1R activation. Silencing nAChR, α1 subunit of L-type VDCC, or various vesicular trafficking curators, including synaptotagmins and Rabs, or blockade of nAChR/VDCC-mediated Ca2+ influx significantly suppresses NNK-induced IGF2 exocytosis, transformation and tumorigenesis of lung epithelial cells. Publicly available database reveals inverse correlation between use of calcium channel blockers and lung cancer diagnosis. Our data indicate that NNK disrupts the regulated pathway of IGF2 exocytosis and promotes lung tumorigenesis. PMID:27666821

  8. (-) Epicatechin attenuates mitochondrial damage by enhancing mitochondrial multi-marker enzymes, adenosine triphosphate and lowering calcium in isoproterenol induced myocardial infarcted rats.

    PubMed

    Stanely Mainzen Prince, P

    2013-03-01

    Cardiac mitochondrial damage plays an important role in the pathology of myocardial infarction. The protective effects of (-) epicatechin on cardiac mitochondrial damage in isoproterenol induced myocardial infarction were evaluated in rats. Rats were pretreated with (-) epicatechin (20 mg/kg body weight) daily for a period of 21 days. After the pretreatment period, isoproterenol (100 mg/kg body weight) was injected subcutaneously into rats twice at an interval of 24 h to induce myocardial infarction. Isoproterenol induced myocardial infarcted rats showed a significant increase in the levels of cardiac diagnostic markers, heart mitochondrial lipid peroxidation, calcium, and a significant decrease in the activities/levels of heart mitochondrial glutathione peroxidase, glutathione reductase, reduced glutathione, isocitrate, succinate, malate, α-ketoglutarate and NADH-dehydrogenases, cytochrome-C-oxidase and adenosine triphosphate. (-) Epicatechin pretreatment showed significant protective effects on all the biochemical parameters evaluated. The in vitro study revealed the superoxide and hydroxyl radical scavenging activity of (-) epicatechin. The possible mechanisms for the beneficial effects of (-) epicatechin on cardiac mitochondria could be attributed to scavenging of free radicals, decreasing calcium, increasing multi-enzymes (antioxidant, tricarboxylic acid cycle and respiratory chain enzymes), reduced glutathione and adenosine triphosphate. Thus, (-) epicatechin attenuated mitochondrial damage in isoproterenol induced myocardial infarcted rats. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Low-level laser irradiation modulates brain-derived neurotrophic factor mRNA transcription through calcium-dependent activation of the ERK/CREB pathway.

    PubMed

    Yan, Xiaodong; Liu, Juanfang; Zhang, Zhengping; Li, Wenhao; Sun, Siguo; Zhao, Jian; Dong, Xin; Qian, Jixian; Sun, Honghui

    2017-01-01

    Low-level laser (LLL) irradiation has been reported to promote neuronal differentiation, but the mechanism remains unclear. Brain-derived neurotrophic factor (BDNF) has been confirmed to be one of the most important neurotrophic factors because it is critical for the differentiation and survival of neurons during development. Thus, this study aimed to investigate the effects of LLL irradiation on Bdnf messenger RNA (mRNA) transcription and the molecular pathway involved in LLL-induced Bdnf mRNA transcription in cultured dorsal root ganglion neurons (DRGNs) using Ca 2+ imaging, pharmacological detections, RNA interference, immunocytochemistry assay, Western blot, and qPCR analysis. We show here that LLL induced increases in the [Ca 2+ ] i level, Bdnf mRNA transcription, cAMP-response element-binding protein (CREB) phosphorylation, and extracellular signal-regulated kinase (ERK) phosphorylation, mediated by Ca 2+ release via inositol triphosphate receptor (IP3R)-sensitive calcium (Ca 2+ ) stores. Blockade of Ca 2+ increase suppressed Bdnf mRNA transcription, CREB phosphorylation, and ERK phosphorylation. Downregulation of phosphorylated (p)-CREB reduced Bdnf mRNA transcription triggered by LLL. Furthermore, blockade of ERK using PD98059 inhibitor reduced p-CREB and Bdnf mRNA transcription induced by LLL. Taken together, these findings establish the Ca 2+ -ERK-CREB cascade as a potential signaling pathway involved in LLL-induced Bdnf mRNA transcription. To our knowledge, this is the first report of the mechanisms of Ca 2+ -dependent Bdnf mRNA transcription triggered by LLL. These findings may help further explore the complex molecular signaling networks in LLL-triggered nerve regeneration in vivo and may also provide experimental evidence for the development of LLL for clinical applications.

  10. Nitroprusside inhibits calcium-induced impairment of red blood cell deformability.

    PubMed

    Barodka, Viachaslau; Mohanty, Joy G; Mustafa, Asif K; Santhanam, Lakshmi; Nyhan, Aoibhinn; Bhunia, Anil K; Sikka, Gautam; Nyhan, Daniel; Berkowitz, Dan E; Rifkind, Joseph M

    2014-02-01

    Red blood cell (RBC) deformation is critical for microvascular perfusion and oxygen delivery to tissues. Abnormalities in RBC deformability have been observed in aging, sickle cell disease, diabetes, and preeclampsia. Although nitric oxide (NO) prevents decreases in RBC deformability, the underlying mechanism is unknown. As an experimental model, we used ionophore A23187-mediated calcium influx in RBCs to reduce their deformability and investigated the role of NO donor sodium nitroprusside (SNP) and KCa3.1 (Gardos) channel blockers on RBC deformability (measured as elongation index [EI] by microfluidic ektacytometry). RBC intracellular Ca(2+) and extracellular K(+) were measured by inductively coupled plasma mass spectrometry and potassium ion selective electrode, respectively. SNP treatment of RBCs blocked the Ca(2+) (approx. 10 μmol/L)-induced decrease in RBC deformability (EI 0.34 ± 0.02 vs. 0.09 ± 0.01, control vs. Ca(2+) loaded, p < 0.001; and EI 0.37 ± 0.02 vs. 0.30 ± 0.01, SNP vs. SNP plus Ca(2+) loaded) as well as Ca(2+) influx and K(+) efflux. The SNP effect was similar to that observed after pharmacologic blockade of the KCa3.1 channel (with charybdotoxin or extracellular medium containing isotonic K(+) concentration). In RBCs from KCa3.1(-/-) mice, 10 μmol/L Ca(2+) loading did not decrease cellular deformability. A preliminary attempt to address the molecular mechanism of SNP protection suggests the involvement of cell surface thiols. Our results suggest that nitroprusside treatment of RBCs may protect them from intracellular calcium increase-mediated stiffness, which may occur during microvascular perfusion in diseased states, as well as during RBC storage. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  11. Proteomic Analysis of Calcium Effects on Soybean Root Tip under Flooding and Drought Stresses.

    PubMed

    Wang, Xin; Komatsu, Setsuko

    2017-08-01

    Flooding and drought are disadvantageous environmental conditions that induce cytosolic calcium in soybean. To explore the effects of flooding- and drought-induced increases in calcium, a gel-free/label-free proteomic analysis was performed. Cytosolic calcium was decreased by blocking calcium channels in the endoplasmic reticulum (ER) and plasma membrane under both stresses. Calnexin, protein disulfide isomerase, heat shock proteins and thioredoxin were predominantly affected as the ER proteins in response to calcium, and ER-associated degradation-related proteins of HCP-like superfamily protein were up-regulated under stress exposure and then down-regulated. Glycolysis, fermentation, the tricarboxylic acid cycle and amino acid metabolism were mainly induced as the types of cellular metabolism in response to calcium under both stresses. Pyruvate decarboxylase was increased and decreased under flooding and drought, respectively, and was further decreased by the reduction of cytosolic calcium; however, it was recovered by exogenous calcium under both stresses. Furthermore, pyruvate decarboxylase activity was increased under flooding, but decreased under drought. These results suggest that calcium is involved in protein folding in the ER, and ER-associated degradation might alleviate ER stress during the early stage of both stresses. Furthermore, calcium appears to modify energy metabolism, and pyruvate decarboxylase may be a key enzyme in this process under flooding and drought. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  12. Modulation of polyepoxysuccinic acid on crystallization of calcium oxalate

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

    Zhang, Yanqing; Tang, Yongming, E-mail: tangym@njtech.edu.cn; Xu, Jinqiu

    The influence of polyepoxysuccinic acid (PESA) on the phase composition and crystal morphology of calcium oxalate was investigated in this paper. It was found that the presence of PESA inhibited the growth of the monoclinic calcium oxalate monohydrate (COM) crystal and promoted the nucleation of the tetragonal calcium oxalate dihydrate (COD). In addition, with the increase in PESA concentration, the aggregation of COD crystals was reduced but the particle size was increased. Under the conditions of low calcium-to-oxalate ratio and high CaOx concentration, PESA could not effectively stabilize the formation of COD. Based on molecular dynamic simulations, the adsorption ofmore » PESA on CaOx crystal faces was confirmed. - Graphical abstract: Introduction of PESA into crystallization solutions promotes the formation of calcium oxalate dehydrate and modifies the morphology of crystals. - Highlights: • PESA induces the formation of COD at low supersaturation. • Establishment of Ca-rich surface augments the adsorption of PESA. • At Ca/Ox=0.5 PESA cannot induce the formation of COD compared with Ca/Ox=2. • Interaction of PESA with COM faces is stronger than that with COD faces.« less

  13. Increase in cytosolic calcium maintains plasma membrane integrity through the formation of microtubule ring structure in apoptotic cervical cancer cells induced by trichosanthin.

    PubMed

    Wang, Ping; Xu, Shujun; Zhao, Kai; Xiao, Bingxiu; Guo, Junming

    2009-11-01

    This study investigates the role of dysregulated cytosolic free calcium ([Ca(2+)]c) homeostasis on microtubule (MT) ring structure in apoptotic cervical cancer (HeLa) cells induced by trichosanthin (TCS), a type I ribosome inactivating protein (RIP). The TCS-induced decrease in cell viability was significantly enhanced in combination with the specific calcium chelator, EGTA-AM. Sequestration of [Ca(2+)]c markedly disrupted the special MT ring structure. Furthermore, TCS tended to increase LDH release, whereas no significant differences were observed until 48 h of the treatment. In contrast, combined addition of EGTA-AM or colchicine (an inhibitor of tubulin polymerization) significantly reinforced LDH release. The data suggest that TCS-elevated [Ca(2+)]c maintains plasma membrane integrity via the formation of the MT ring structure in apoptotic HeLa cells.

  14. Calcium induced ATP synthesis: Isotope effect, magnetic parameters and mechanism

    NASA Astrophysics Data System (ADS)

    Buchachenko, A. L.; Kuznetsov, D. A.; Breslavskaya, N. N.; Shchegoleva, L. N.; Arkhangelsky, S. E.

    2011-03-01

    ATP synthesis by creatine kinase with calcium ions is accompanied by 43Ca/ 40Ca isotope effect: the enzyme with 43Ca 2+ was found to be 2.0 ± 0.3 times more active than enzymes, in which Ca 2+ ions have nonmagnetic nuclei 40Ca. The effect demonstrates that primary reaction in ATP synthesis is electron transfer between reaction partners, Сa( HO)n2+ ( n ⩽ 3) and Ca 2+(ADP) 3-. It generates ion-radical pair, in which spin conversion results in the isotope effect. Magnetic parameters (g-factors and HFC constants a( 43Ca) and a( 31P)) confirm that namely terminal oxygen atom of the ADP ligand in the complex Ca 2+(ADP) 3- donates electron to the Ca( HO)n2+ ion.

  15. Study on ATP concentration changes in cytosol of individual cultured neurons during glutamate-induced deregulation of calcium homeostasis.

    PubMed

    Surin, A M; Gorbacheva, L R; Savinkova, I G; Sharipov, R R; Khodorov, B I; Pinelis, V G

    2014-02-01

    For the first time, simultaneous monitoring of changes in the concentration of cytosolic ATP ([ATP]c), pH (pHc), and intracellular free Ca2+ concentration ([Ca2+]i) of the individual neurons challenged with toxic glutamate (Glu) concentrations was performed. To this end, the ATP-sensor AT1.03, which binds to ATP and therefore enhances the efficiency of resonance energy transfer between blue fluorescent protein (energy donor) and yellow-green fluorescent protein (energy acceptor), was expressed in cultured hippocampal neurons isolated from 1-2-day-old rat pups. Excitation of fluorescence in the acceptor protein allowed monitoring changes in pHc. Cells were loaded with fluorescent low-affinity Ca2+ indicators Fura-FF or X-rhod-FF to register [Ca2+]i. It was shown that Glu (20 µM, glycine 10 µM, Mg2+-free) produced a rapid acidification of the cytosol and decrease in [ATP]c. An approximately linear relationship (r(2) = 0.56) between the rate of [ATP]c decline and latency of glutamate-induced delayed calcium deregulation (DCD) was observed: higher rate of [ATP]c decrease corresponded to shorter DCD latency period. DCD began with a decrease in [ATP]c of as much as 15.9%. In the phase of high [Ca2+]i, the plateau of [ATP]c dropped to 10.4% compared to [ATP]c in resting neurons (100%). In the presence of the Na+/K+-ATPase inhibitor ouabain (0.5 mM), glutamate-induced reduction in [ATP]c in the phase of the high [Ca2+]i plateau was only 36.6%. Changes in [ATP]c, [Ca2+]i, mitochondrial potential, and pHc in calcium-free or sodium-free buffers, as well as in the presence of the inhibitor of Na+/K+-ATPase ouabain (0.5 mM), led us to suggest that in addition to increase in proton conductivity and decline in [ATP]c, one of the triggering factors of DCD might be a reversion of the neuronal plasma membrane Na+/Ca2+ exchange.

  16. Nuclear Calcium Buffering Capacity Shapes Neuronal Architecture*

    PubMed Central

    Mauceri, Daniela; Hagenston, Anna M.; Schramm, Kathrin; Weiss, Ursula; Bading, Hilmar

    2015-01-01

    Calcium-binding proteins (CaBPs) such as parvalbumin are part of the cellular calcium buffering system that determines intracellular calcium diffusion and influences the spatiotemporal dynamics of calcium signals. In neurons, CaBPs are primarily localized to the cytosol and function, for example, in nerve terminals in short-term synaptic plasticity. However, CaBPs are also expressed in the cell nucleus, suggesting that they modulate nuclear calcium signals, which are key regulators of neuronal gene expression. Here we show that the calcium buffering capacity of the cell nucleus in mouse hippocampal neurons regulates neuronal architecture by modulating the expression levels of VEGFD and the complement factor C1q-c, two nuclear calcium-regulated genes that control dendrite geometry and spine density, respectively. Increasing the levels of nuclear calcium buffers by means of expression of a nuclearly targeted form of parvalbumin fused to mCherry (PV.NLS-mC) led to a reduction in VEGFD expression and, as a result, to a decrease in total dendritic length and complexity. In contrast, mRNA levels of the synapse pruning factor C1q-c were increased in neurons expressing PV.NLS-mC, causing a reduction in the density and size of dendritic spines. Our results establish a close link between nuclear calcium buffering capacity and the transcription of genes that determine neuronal structure. They suggest that the development of cognitive deficits observed in neurological conditions associated with CaBP deregulation may reflect the loss of necessary structural features of dendrites and spines. PMID:26231212

  17. Physiology of Calcium, Phosphate, Magnesium and Vitamin D.

    PubMed

    Allgrove, Jeremy

    2015-01-01

    The physiology of calcium and the other minerals involved in its metabolism is complex and intimately linked to the physiology of bone. Five principal humoral factors are involved in maintaining plasma concentrations of calcium, magnesium and phosphate and in coordinating the balance between their content in bone. The transmembrane transport of these elements is dependent on a series of complex mechanisms that are partly controlled by these hormones. The plasma concentration of calcium is initially sensed by a calcium-sensing receptor, which then sets up a cascade of events that initially determines parathyroid hormone secretion and eventually results in a specific action within the target organs, mainly bone and kidney. This chapter describes the physiology of these humoral factors and relates them to the pathological processes that give rise to disorders of calcium, phosphate and magnesium metabolism as well as of bone metabolism. This chapter also details the stages in the calcium cascade, describes the effects of calcium on the various target organs, gives details of the processes by which phosphate and magnesium are controlled and summarises the metabolism of vitamin D. The pathology of disorders of bone and calcium metabolism is described in detail in the relevant chapters. © 2015 S. Karger AG, Basel.

  18. Influence of betel quid on effect of calcium channel blockers on isoprenaline induced myocardial necrosis in mice.

    PubMed

    Kumar, Vinod; Asdaq, Syed Mohammed Basheeruddin; Asad, Mohammed

    2009-09-01

    It is known that chewing Betel quid with tobacco (BQT) or without tobacco (BQ) is a major etiological factor for cardiovascular complications and calcium channel blockers (CCBs) are the major class of drugs prescribed widely for myocardial disturbances. The possible pharmacodynamic interaction between CCBs (verapamil, amlodipine and diltiazem) and BQ/BQT was studied on isoproterenol (ISO)-induced myocardial necrosis in mice. Influence of (CCBs) therapy on pretreated animals at times of myocardial stress were determined by estimating diagnostic marker enzymes such as lactate dehydrogenase (LDH) and creatine phosphokinase isoenzyme (CK-MB) in serum and heart tissue homogenate (HTH). Administration of CCBs to mice pretreated with BQ produced a significant decrease and increase in biomarker enzyme levels in serum and HTH respectively. Further, incorporation of diltiazem and amlodipine in BQT pretreated mice significantly elevated enzyme levels in HTH, whereas, amlodipine administration during BQT treatment showed significant fall in enzyme levels in serum. The results indicated that BQT is cardiotoxic and its effect cannot be reversed using CCBs while BQ is cardioprotective, whose activity was further augmented by amlodipine. Histopathological studies confirmed the biochemical findings.

  19. Role of calcium activated kinases and phosphatases in heat shock factor-1 activation.

    PubMed

    Soncin, F; Asea, A; Zhang, X; Stevenson, M A; Calderwood, S K

    2000-12-01

    HSF-1 is regulated at multiple molecular levels through intra- and intermolecular protein-protein interactions as well as by post-translational modification through phosphorylation. We have found that elevating intracellular calcium ion levels by exposure to the ionophore A23187 or thapsigargin inhibits the conversion of HSF-1 from a latent cytoplasmic form to its nuclear/DNA binding form. To examine a role for calcium/calmodulin regulated enzymes in this process, we examined the ability of specific inhibitors to abrogate the effects of calcium elevation. While the inhibitor of calmodulin dependent kinase II, KCN62 enhanced activation of HSF-1 during heat shock, it failed to block the inhibitory effects of calcium increase. By contrast, the immunosuppresant drugs cyclosporin A and FK506 abolished the effects of calcium elevation on HSF-1 activation. As the biological effects of the drugs are effected through inhibition of the calcium/calmodulin regulated phosphatase calcineurin, this suggests a role for calcineurin in antagonizing HSF-1 activity. The experiments suggest the existence of phosphorylated residue(s) in HSF-1 important in one or more of the processes that lead to activation (trimerization, nuclear localization, DNA binding) and which becomes dephosphorylated due to the activation of a calcium/calmodulin/calcineurin complex.

  20. Impaired Compensation for Salt-Induced Urinary Calcium Loss in a Space Flight Model

    NASA Technical Reports Server (NTRS)

    Navidi, Meena; Harper, J. S.; Evans, J.; Fung, P.; Wolinsky, I.; Arnaud, S. B.; Wade, Charles E. (Technical Monitor)

    1994-01-01

    The loss of urinary calcium (UCa) induced by high sodium (HiNa) diets is compensated for by an increase in net intestinal Ca absorption (abs.). To determine the capacity of the intestine to absorb Ca in a space flight model in which the formation of 1,25-dihydroxyvitamin D (1,25-D) is suppressed, we induced Ca loss with HiNa diets (8%) and restricted dietary Ca (0.2%). In 200 g rats with hind limbs unloaded by tail suspension (S), we examined intestinal Ca abs. by direct measurement in the duodenum (everted gut sac or S/M), vitamin D receptors (VDR) and Ca balance. We also measured serum ionized calcium (ICa), pH, parathyroid hormone (PTH) and 1,25D. PTH was related to ICa (r = -0.44, p is less than 0.02), pH (r = -0.47, p is less than 0.02) and %Ca abs. (r = -0.40, p is less than 0.05). 1,25-D was related to %Ca abs. (r = 0.60, p is less than 0.001) but not VDR or S/M. Effects of the model were lower serum 1,25-D (110 +/- 59 vs. 199 +/- 80 pg/ml, p is less than 0.005), %Ca abs. (83 +/- 6.9 vs. 93 +/- 3.2, p is less than 0.03) and Ca balance (27 +/- 0.2 vs. 30 +/- 0.3 mg/d, p is less than 0.001) in S than controls (C). The HiNa diet increased UCa excretion from 2 to 13% of dietary Ca. Responses to HiNa diets, compared to normal Na, revealed no differences in 1,25-D, Ca abs. or VDR. Ca balances were lower in HiNa (27 +/- 0.3 vs. 30 +/- 0.4 mg/d, p is less than 0.001) in spite of higher Ca intakes. The failure of S rats fed HiNa diets to increase Ca abs. in response to Na-induced Ca loss appears to be related to suppressed 1,25-D in the space flight model, the cause of which remains obscure.

  1. Omega-conotoxin- and nifedipine-insensitive voltage-operated calcium channels mediate K(+)-induced release of pro-thyrotropin-releasing hormone-connecting peptides Ps4 and Ps5 from perifused rat hypothalamic slices.

    PubMed

    Valentijn, K; Tranchand Bunel, D; Vaudry, H

    1992-07-01

    The rat thyrotropin-releasing hormone (TRH) precursor (prepro-TRH) contains five copies of the TRH progenitor sequence linked together by intervening sequences. Recently, we have shown that the connecting peptides prepro-TRH-(160-169) (Ps4) and prepro-TRH-(178-199) (Ps5) are released from rat hypothalamic neurones in response to elevated potassium concentrations, in a calcium-dependent manner. In the present study, the role of voltage-operated calcium channels in potassium-induced release of Ps4 and Ps5 was investigated, using a perifusion system for rat hypothalamic slices. The release of Ps4 and Ps5 stimulated by potassium (70 mM) was blocked by the inorganic ions Co2+ (2.6 mM) and Ni2+ (5 mM). In contrast, the stimulatory effect of KCl was insensitive to Cd2+ (100 microM). The dihydropyridine antagonist nifedipine (10 microM) had no effect on K(+)-evoked release of Ps4 and Ps5. Furthermore, the response to KCl was not affected by nifedipine (10 microM) in combination with diltiazem (1 microM), a benzothiazepine which increases the affinity of dihydropyridine antagonists for their receptor. The dihydropyridine agonist BAY K 8644, at concentrations as high as 1 mM, did not stimulate the basal secretion of Ps4 and Ps5. In addition, BAY K 8644 had no potentiating effect on K(+)-induced release of Ps4 and Ps5. The marine cone snail toxin omega-conotoxin, a blocker of both L- and N-type calcium channels had no effect on the release of Ps4 and Ps5 stimulated by potassium. Similarly, the omega-conopeptide SNX-111, a selective blocker of N-type calcium channels, did not inhibit the stimulatory effect of potassium. The release of Ps4 and Ps5 evoked by high K+ was insensitive to the non-selective calcium channel blocker verapamil (20 microM). Amiloride (1 microM), a putative blocker of T-type calcium channels, did not affect KCl-induced secretion of the two connecting peptides. Taken together, these results indicate that two connecting peptides derived from the pro-TRH, Ps

  2. Effect of ticlopidine ex vivo on platelet intracellular calcium mobilization

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

    Derian, C.K.; Friedman, P.A.

    1988-04-01

    The antiplatelet compound ticlopidine exerts its potent inhibitory activity through an as yet undetermined mechanism(s). The goal of this study was to determine the effect, if any, of ticlopidine ex vivo on platelet calcium mobilization. Ticlopidine inhibited ADP-induced platelet aggregation by 50-80%. In the presence of 1 mM EGTA, ticlopidine inhibited ADP- and thrombin-stimulated increases in (Ca2+)i in fura-2 loaded platelets. We evaluated further the effect of ticlopidine on calcium mobilization by examining both agonist-stimulated formation of inositol trisphosphate in intact platelets and the ability of inositol trisphosphate to release /sup 45/Ca from intracellular sites in permeabilized cells. We showmore » here that while ticlopidine significantly affected agonist-induced intracellular calcium mobilization in intact platelets, the drug was without effect on agonist-stimulated formation of inositol trisphosphate in intact platelets and on inositol trisphosphate-induced /sup 45/Ca release in saponin-permeabilized platelets. Our study demonstrates that ticlopidine exerts at least part of its effect via inhibition of intracellular calcium mobilization but that its site of action remains to be determined.« less

  3. Ferulic acid prevents cerebral ischemic injury-induced reduction of hippocalcin expression.

    PubMed

    Koh, Phil-Ok

    2013-07-01

    Intracellular calcium overload is a critical pathophysiological factor in ischemic injury. Hippocalcin is a neuronal calcium sensor protein that buffers intracellular calcium levels and protects cells from apoptotic stimuli. Ferulic acid exerts a neuroprotective effect in cerebral ischemia through its anti-oxidant and anti-inflammation activity. This study investigated whether ferulic acid contributes to hippocalcin expression during cerebral ischemia and glutamate exposure-induced neuronal cell death. Rats were immediately treated with vehicle or ferulic acid (100 mg/kg, i.v.) after middle cerebral artery occlusion (MCAO). Brain tissues were collected 24 h after MCAO and followed by assessment of cerebral infarct. Ferulic acid reduced MCAO-induced infarct regions. A proteomics approach elucidated a decrease in hippocalcin in MCAO-operated animals, ferulic acid attenuates the injury-induced decrease in hippocalcin expression. Reverse transcription-polymerase chain reaction and Western blot analyses confirmed that ferulic acid prevents the injury-induced decrease in hippocalcin. In cultured HT22 hippocampal cells, glutamate exposure increased the intracellular Ca(2+) levels, whereas ferulic acid attenuated this increase. Moreover, ferulic acid attenuated the glutamate toxicity-induced decrease in hippocalcin expression. These findings can suggest the possibility that ferulic acid exerts a neuroprotective effect through modulating hippocalcine expression and regulating intracellular calcium levels. Copyright © 2013 Wiley Periodicals, Inc.

  4. Relationship between ketamine-induced developmental neurotoxicity and NMDA receptor-mediated calcium influx in neural stem cell-derived neurons.

    PubMed

    Wang, Cheng; Liu, Fang; Patterson, Tucker A; Paule, Merle G; Slikker, William

    2017-05-01

    Ketamine, a noncompetitive NMDA receptor antagonist, is used as a general anesthetic and recent data suggest that general anesthetics can cause neuronal damage when exposure occurs during early brain development. To elucidate the underlying mechanisms associated with ketamine-induced neurotoxicity, stem cell-derived models, such as rodent neural stem cells harvested from rat fetuses and/or neural stem cells derived from human induced pluripotent stem cells (iPSC) can be utilized. Prolonged exposure of rodent neural stem cells to clinically-relevant concentrations of ketamine resulted in elevated NMDA receptor levels as indicated by NR1subunit over-expression in neurons. This was associated with enhanced damage in neurons. In contrast, the viability and proliferation rate of undifferentiated neural stem cells were not significantly affected after ketamine exposure. Calcium imaging data indicated that 50μM NMDA did not cause a significant influx of calcium in typical undifferentiated neural stem cells; however, it did produce an immediate elevation of intracellular free Ca 2+ [Ca 2+ ] i in differentiated neurons derived from the same neural stem cells. This paper reviews the literature on this subject and previous findings suggest that prolonged exposure of developing neurons to ketamine produces an increase in NMDA receptor expression (compensatory up-regulation) which allows for a higher/toxic influx of calcium into neurons once ketamine is removed from the system, leading to neuronal cell death likely due to elevated reactive oxygen species generation. The absence of functional NMDA receptors in cultured neural stem cells likely explains why clinically-relevant concentrations of ketamine did not affect undifferentiated neural stem cell viability. Published by Elsevier B.V.

  5. Hypoxia inducible factors in hepatocellular carcinoma

    PubMed Central

    Chen, Chu; Lou, Tao

    2017-01-01

    Hepatocellular carcinoma is one of the most prevalent and lethal cancers with limited therapeutic options. Pathogenesis of this disease involves tumor hypoxia and the activation of hypoxia inducible factors. In this review, we describe the current understanding of hypoxia signaling pathway and summarize the expression, function and target genes of hypoxia inducible factors in hepatocellular carcinoma. We also highlight the recent progress in hypoxia-targeted therapeutic strategies in hepatocellular carcinoma and discuss further the future efforts for the study of hypoxia and/or hypoxia inducible factors in this deadly disease. PMID:28493839

  6. Lipopolysaccharide-induced innate immune factors in the bottlenose dolphin (Tursiops truncatus) detected in expression sequence tag analysis.

    PubMed

    Ohishi, Kazue; Shishido, Reiko; Iwata, Yasunao; Saitoh, Masafumi; Takenaka, Ryota; Ohtsu, Dai; Okutsu, Kenji; Maruyama, Tadashi

    2011-11-01

    EST analysis based on the megaclone-megasorting method was performed using leukocytes from the bottlenose dolphin (Tursiops truncatus) with or without LPS stimulation. A total of 849 upregulated and 384 downregulated EST clones were sequenced, annotated, and functionally classified. Ferritin heavy peptide I was the most abundant upregulated transcript, suggesting that LPS stimulation induced high production of reactive oxygen species, which were sequestered in ferritin. Among the immune factors, the transcripts coding for an IL-1Ra, homologs to bovine serum amyloid A3, and canine intercellular adhesion molecule-1 were highly expressed. Markedly downregulated transcripts of immune factors were those for homologs of calcium-binding proteins belonging to the S100 family, S100A12, S100A8, and S100A6. Time-course experiments on the expression of some immune factors including IL-1Ra suggested that these factors interact and control cetacean innate immunity. © 2011 The Societies and Blackwell Publishing Asia Pty Ltd.

  7. Apical closure of mature molar roots with the use of calcium hydroxide.

    PubMed

    Rotstein, I; Friedman, S; Katz, J

    1990-11-01

    Calcium hydroxide may induce apical root closure in affected mature teeth as well as in immature teeth. Once an apical hard tissue barrier is formed, a permanent root canal filling can be safely condensed. Two cases are described in which calcium hydroxide induced apical root closure in mature molar teeth where the apical constriction was lost because of chronic inflammatory process.

  8. Malignant hyperthermia and calcium-induced heat production.

    PubMed

    Ueda, I; Shinoda, F; Kamaya, H; Krishna, P R

    1994-05-01

    The abnormal increase in intracellular Ca++ in malignant hyperthermia (MH) is well documented, but the link between the increased Ca++ concentration and high temperature remains speculative. We investigated the possibility that the Ca(++)-induced change in the state of cell membranes may contribute to the temperature elevation. Calcium ion transforms phospholipid membranes from the fluid to solid state. This is analogous to the freezing of water, and liberates latent heat. Differential titration calorimetry (DTC) measures heat production or absorption during ligand binding to macromolecules. When CaCl2 solution was added to anionic dimyristoylphosphatidic acid (DMPA) and dimyristoylphosphatidylglycerol (DMPG) vesicle membranes in incremental doses, DTC showed that the heat production suddenly increased when the Ca++ concentration exceeded about 120 microM. At this Ca++ concentration range, these lipid membranes underwent phase transition. The latent heat of transition was measured by differential scanning calorimetry (DSC). The values were 7.1 +/- 0.7 (SD, n = 4) kcal.mol-1 of DMPA and 6.8 +/- 0.7 (SD, n = 4) kcal.mol-1 of DMPG. The study shows that Ca++ produces heat when bound to lipid membranes. We are not proposing, however, that this is the sole source of heat. We contend that the lipid phase transition is one of the heat sources and it may trigger a hypermetabolic state by elevating the temperature of cell membranes. Because Ca++ is implicated as the second messenger in signal transduction, multiple systems may be involved. More studies are needed to clarify how Ca++ increases body temperature.

  9. Optimization of Direct Fibroblast Reprogramming to Cardiomyocytes Using Calcium Activity as a Functional Measure of Success

    PubMed Central

    Addis, Russell C.; Ifkovits, Jamie L.; Pinto, Filipa; Kellam, Lori D.; Esteso, Paul; Rentschler, Stacey; Christoforou, Nicolas; Epstein, Jonathan A.; Gearhart, John D.

    2013-01-01

    Direct conversion of fibroblasts to induced cardiomyocytes (iCMs) has great potential for regenerative medicine. Recent publications have reported significant progress, but the evaluation of reprogramming has relied upon non-functional measures such as flow cytometry for cardiomyocyte markers or GFP expression driven by a cardiomyocyte-specific promoter. The issue is one of practicality: the most stringent measures - electrophysiology to detect cell excitation and the presence of spontaneously contracting myocytes - are not readily quantifiable in the large numbers of cells screened in reprogramming experiments. However, excitation and contraction are linked by a third functional characteristic of cardiomyocytes: the rhythmic oscillation of intracellular calcium levels. We set out to optimize direct conversion of fibroblasts to iCMs with a quantifiable calcium reporter to rapidly assess functional transdifferentiation. We constructed a reporter system in which the calcium indicator GCaMP is driven by the cardiomyocyte-specific Troponin T promoter. Using calcium activity as our primary outcome measure, we compared several published combinations of transcription factors along with novel combinations in mouse embryonic fibroblasts. The most effective combination consisted of Hand2, Nkx2.5, Gata4, Mef2c, and Tbx5 (HNGMT). This combination is >50-fold more efficient than GMT alone and produces iCMs with cardiomyocyte marker expression, robust calcium oscillation, and spontaneous beating that persists for weeks following inactivation of reprogramming factors. HNGMT is also significantly more effective than previously published factor combinations for the transdifferentiation of adult mouse cardiac fibroblasts to iCMs. Quantification of calcium function is a convenient and effective means for the identification and evaluation of cardiomyocytes generated by direct reprogramming. Using this stringent outcome measure, we conclude that HNGMT produces iCMs more efficiently

  10. Optimization of direct fibroblast reprogramming to cardiomyocytes using calcium activity as a functional measure of success.

    PubMed

    Addis, Russell C; Ifkovits, Jamie L; Pinto, Filipa; Kellam, Lori D; Esteso, Paul; Rentschler, Stacey; Christoforou, Nicolas; Epstein, Jonathan A; Gearhart, John D

    2013-07-01

    Direct conversion of fibroblasts to induced cardiomyocytes (iCMs) has great potential for regenerative medicine. Recent publications have reported significant progress, but the evaluation of reprogramming has relied upon non-functional measures such as flow cytometry for cardiomyocyte markers or GFP expression driven by a cardiomyocyte-specific promoter. The issue is one of practicality: the most stringent measures - electrophysiology to detect cell excitation and the presence of spontaneously contracting myocytes - are not readily quantifiable in the large numbers of cells screened in reprogramming experiments. However, excitation and contraction are linked by a third functional characteristic of cardiomyocytes: the rhythmic oscillation of intracellular calcium levels. We set out to optimize direct conversion of fibroblasts to iCMs with a quantifiable calcium reporter to rapidly assess functional transdifferentiation. We constructed a reporter system in which the calcium indicator GCaMP is driven by the cardiomyocyte-specific Troponin T promoter. Using calcium activity as our primary outcome measure, we compared several published combinations of transcription factors along with novel combinations in mouse embryonic fibroblasts. The most effective combination consisted of Hand2, Nkx2.5, Gata4, Mef2c, and Tbx5 (HNGMT). This combination is >50-fold more efficient than GMT alone and produces iCMs with cardiomyocyte marker expression, robust calcium oscillation, and spontaneous beating that persist for weeks following inactivation of reprogramming factors. HNGMT is also significantly more effective than previously published factor combinations for the transdifferentiation of adult mouse cardiac fibroblasts to iCMs. Quantification of calcium function is a convenient and effective means for the identification and evaluation of cardiomyocytes generated by direct reprogramming. Using this stringent outcome measure, we conclude that HNGMT produces iCMs more efficiently than

  11. Mechanisms of arrhythmogenesis related to calcium-driven alternans in a model of human atrial fibrillation

    NASA Astrophysics Data System (ADS)

    Chang, Kelly C.; Trayanova, Natalia A.

    2016-11-01

    The occurrence of atrial fibrillation (AF) is associated with progressive changes in the calcium handling system of atrial myocytes. Calcium cycling instability has been implicated as an underlying mechanism of electrical alternans observed in patients who experience AF. However, the extent to which calcium-induced alternation of electrical activity in the atria contributes to arrhythmogenesis is unknown. In this study, we investigated the effects of calcium-driven alternans (CDA) on arrhythmia susceptibility in a biophysically detailed, 3D computer model of the human atria representing electrical and structural remodeling secondary to chronic AF. We found that elevated propensity to CDA rendered the atria vulnerable to ectopy-induced arrhythmia. It also increased the complexity and persistence of arrhythmias induced by fast pacing, with unstable scroll waves meandering and frequently breaking up to produce multiple wavelets. Our results suggest that calcium-induced electrical instability may increase arrhythmia vulnerability and promote increasing disorganization of arrhythmias in the chronic AF-remodeled atria, thus playing an important role in the progression of the disease.

  12. Hematological changes in nephritis in poultry induced by diets high in protein, high in calcium, containing urea, or deficient in vitamin A.

    PubMed

    Chandra, M; Singh, B; Singh, N; Ahuja, S P

    1984-04-01

    Nephritis was induced in 300, 18-day-old male Arbor Acre broiler chicks by feeding diets high (42.28%) in protein, high (3.27%) in calcium, containing urea (5%), or deficient in vitamin A. Various hematological parameters were studied at weekly intervals. Normocytic-normochromic anemia, characterized by a decrease in total erythrocyte counts, hemoglobin, packed cell volume, and an increase in erythrocyte sedimentation rate, was evident in the birds kept on diets high in protein, high in calcium, or deficient in vitamin A. Increased total erythrocytes, hemoglobin packed cell volume, and erythrocyte sedimentation rate was observed in birds fed urea. Differential leucocyte counts revealed lymphopenia, heterophilia and monocytosis in birds kept on diets high in protein, containing urea, or deficient in vitamin A. However, lymphocytosis, heteropenia , and monocytosis were recorded in birds fed the high calcium diet.

  13. Calcium bioavailability and kinetics of calcium ascorbate and calcium acetate in rats.

    PubMed

    Cai, Jianwei; Zhang, Qinmin; Wastney, Meryl E; Weaver, Connie M

    2004-01-01

    The objective was to investigate the bioavailability and mechanism of calcium absorption of calcium ascorbate (ASC) and calcium acetate (AC). A series of studies was performed in adult Sprague-Dawley male rats. In the first study, each group of rats (n = 10/group) was assigned to one of the five test meals labeled with (45)Ca: (i) 25 mg calcium as heated ASC or (ii) unheated ASC, (iii) 25 mg calcium as unheated AC, (iv) 3.6 mg Ca as unheated ASC, or (v) unheated AC. Femur uptake indicated better calcium bioavailability from ASC than AC at both calcium loads. A 5-min heat treatment partly reduced bioavailability of ASC. Kinetic studies were performed to further investigate the mechanism of superior calcium bioavailability from ASC. Two groups of rats (n = 10/group) received oral doses of 25 mg Ca as ASC or AC. Each dose contained 20 micro Ci (45)Ca. Two additional groups of rats (n = 10/group) received an intravenous injection (iv) of 10 micro Ci (45)Ca after receiving an unlabeled oral dose of 25 mg calcium as ASC or AC. Sequential blood samples were collected over 48 hrs. Urine and fecal samples were collected every 12 hrs for 48 hrs and were analyzed for total calcium and (45)Ca content. Total calcium and (45)Ca from serum, urine, and feces were fitted by a compartment kinetics model with saturable and nonsaturable absorption pathways by WinSAAM (Windows-based Simulation Analysis and Modeling). The difference in calcium bioavailability between the two salts was due to differences in saturable rather than passive intestinal absorption and not to endogenous secretion or calcium deposition rate. The higher bioavailability of calcium ascorbate was due to a longer transit time in the small intestine compared with ASC.

  14. Kidney stone matrix proteins ameliorate calcium oxalate monohydrate induced apoptotic injury to renal epithelial cells.

    PubMed

    Narula, Shifa; Tandon, Simran; Singh, Shrawan Kumar; Tandon, Chanderdeep

    2016-11-01

    Kidney stone formation is a highly prevalent disease, affecting 8-10% of the human population worldwide. Proteins are the major constituents of human kidney stone's organic matrix and considered to play critical role in the pathogenesis of disease but their mechanism of modulation still needs to be explicated. Therefore, in this study we investigated the effect of human kidney stone matrix proteins on the calcium oxalate monohydrate (COM) mediated cellular injury. The renal epithelial cells (MDCK) were exposed to 200μg/ml COM crystals to induce injury. The effect of proteins isolated from human kidney stone was studied on COM injured cells. The alterations in cell-crystal interactions were examined by phase contrast, polarizing, fluorescence and scanning electron microscopy. Moreover, its effect on the extent of COM induced cell injury, was quantified by flow cytometric analysis. Our study indicated the antilithiatic potential of human kidney stone proteins on COM injured MDCK cells. Flow cytometric analysis and fluorescence imaging ascertained that matrix proteins decreased the extent of apoptotic injury caused by COM crystals on MDCK cells. Moreover, the electron microscopic studies of MDCK cells revealed that matrix proteins caused significant dissolution of COM crystals, indicating cytoprotection against the impact of calcium oxalate injury. The present study gives insights into the mechanism implied by urinary proteins to restrain the pathogenesis of kidney stone disease. This will provide a better understanding of the formation of kidney stones which can be useful for the proper management of the disease. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Field testing a questionnaire assessing parental psychosocial factors related to consumption of calcium-rich foods by Hispanic, Asian, and Non-Hispanic white young adolescent children.

    PubMed

    Vyduna, Jennifer L; Boushey, Carol J; Bruhn, Christine M; Reicks, Marla; Auld, Garry W; Cluskey, Mary; Edlefsen, Miriam; Misner, Scottie; Olson, Beth; Schram, Jessica; Zaghloul, Sahar

    2016-01-01

    Intervention strategies to increase calcium intake of parents and young adolescent children could be improved by identifying psychosocial factors influencing intake. The objective was to develop a tool to assess factors related to calcium intake among parents and Hispanic, Asian, and non-Hispanic white young adolescent children (10-13 years) meeting acceptable standards for psychometric properties. A parent questionnaire was constructed from interviews conducted to identify factors. Parents (n = 166) in the United States completed the questionnaire, with seventy-one completing it twice. Two constructs (Attitudes/Preferences and Social/Environmental) were identified and described by eighteen subscales with Cronbach's alpha levels from .50 to .79. Test-retest coefficients ranged from .68 to .85 (p < .001). Several subscales were statistically significantly associated with parent characteristics consistent with theory and published literature. This tool shows promise as a valid and reliable measure of factors associated with calcium-rich food intake among parents and young adolescent children.

  16. Morphine protects SH-SY5Y human neuroblastoma cells against 6-hydroxydopamine-induced cell damage: involvement of anti-oxidant, calcium blocking, and anti-apoptotic properties.

    PubMed

    Elyasi, Leila; Eftekhar-Vaghefi, Seyed Hassan; Esmaeili-Mahani, Saeed

    2014-06-01

    Parkinson's disease is a neurodegenerative disorder characterized by progressive and selective death of dopaminergic neurons. Understanding the neuroprotective effects of chemical reagents has attracted increasing attention. The μ opioid agonist morphine exerts both toxic and protective effects. However, until recently, the neuroprotective role of morphine against 6-hydroxydopamine (6-OHDA)-induced cell death has not been studied. Here, we investigated the effects of morphine on 6-OHDA-induced neurotoxicity in human neuroblastoma SH-SY5Y cell line as an in vitro model of Parkinson's disease. Cell damage was induced by 150 μM 6-OHDA, and the cells' viability was examined by MTT assay. Intracellular calcium, reactive oxygen species (ROS), and mitochondrial membrane potential were determined by the fluorescence spectrophotometry method. Fragmented DNA and biochemical markers of apoptosis were also determined by gel electrophoresis and immunoblotting, respectively. The data showed that 6-OHDA caused a loss of cell viability and mitochondrial membrane potential. In addition, intracellular ROS and calcium levels, activated caspase-3, Bax:Bcl-2 ratio, cytochrome c release, as well as DNA fragmentation were significantly increased in 6-OHDA-treated cells. Incubation of SH-SY5Y cells with morphine (100 μM) elicited a protective effect and reduced biochemical markers of cell damage and death. These results suggest that morphine has neuroprotective effects against 6-OHDA-induced neurotoxicity, and such effects are accompanied by its anti-oxidant, calcium blocking, and anti-apoptotic properties.

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

    PubMed Central

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

    2014-01-01

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

  18. Clarification of serotonin-induced effects in peripheral artery disease observed through the femoral artery response in models of diabetes and vascular occlusion: The role of calcium ions.

    PubMed

    Stojanović, Marko; Prostran, Milica; Janković, Radmila; Radenković, Miroslav

    2017-07-01

    Recent findings have demonstrated that serotonin is an important participant in the development and progression of peripheral artery diseases. Taking this into consideration, the goals of this study were to investigate the effects of serotonin on isolated Wistar rat femoral arteries in both healthy and diabetic animals, with and without artery occlusion, with a particular focus on determining the role of calcium in this process. Contraction experiments with serotonin on intact and denuded femoral artery rings, in the presence or absence of nifedipine and ouabain (both separately, or in combination), as well as Ca 2+ -free Krebs-Ringer bicarbonate solution were performed. The serotonin-induced results were concentration dependent, but only in healthy animals. The endothelium-dependent contraction of the femoral artery was assessed. In healthy animals, the endothelium-reliant part of contraction was dependent on the extracellular calcium, while the smooth muscle-related part was instead dependent on the intracellular calcium. In diabetic animals, both nifedipine and ouabain influenced serotonin-induced vascular effects by blocking intracellular calcium pathways. However, this was diminished after the simultaneous administration of both blockers. © 2017 John Wiley & Sons Australia, Ltd.

  19. Altering calcium influx for selective destruction of breast tumor.

    PubMed

    Yu, Han-Gang; McLaughlin, Sarah; Newman, Mackenzie; Brundage, Kathleen; Ammer, Amanda; Martin, Karen; Coad, James

    2017-03-04

    Human triple-negative breast cancer has limited therapeutic choices. Breast tumor cells have depolarized plasma membrane potential. Using this unique electrical property, we aim to develop an effective selective killing of triple-negative breast cancer. We used an engineered L-type voltage-gated calcium channel (Cec), activated by membrane depolarization without inactivation, to induce excessive calcium influx in breast tumor cells. Patch clamp and flow cytometry were used in testing the killing selectivity and efficiency of human breast tumor cells in vitro. Bioluminescence and ultrasound imaging were used in studies of human triple-negative breast cancer cell MDA-MB-231 xenograft in mice. Histological staining, immunoblotting and immunohistochemistry were used to investigate mechanism that mediates Cec-induced cell death. Activating Cec channels expressed in human breast cancer MCF7 cells produced enormous calcium influx at depolarized membrane. Activating the wild-type Cav1.2 channels expressed in MCF7 cells also produced a large calcium influx at depolarized membrane, but this calcium influx was diminished at the sustained membrane depolarization due to channel inactivation. MCF7 cells expressing Cec died when the membrane potential was held at -10 mV for 1 hr, while non-Cec-expressing MCF7 cells were alive. MCF7 cell death was 8-fold higher in Cec-expressing cells than in non-Cec-expressing cells. Direct injection of lentivirus containing Cec into MDA-MB-231 xenograft in mice inhibited tumor growth. Activated caspase-3 protein was detected only in MDA-MB-231 cells expressing Cec, along with a significantly increased expression of activated caspase-3 in xenograft tumor treated with Cec. We demonstrated a novel strategy to induce constant calcium influx that selectively kills human triple-negative breast tumor cells.

  20. Nuclear Calcium Buffering Capacity Shapes Neuronal Architecture.

    PubMed

    Mauceri, Daniela; Hagenston, Anna M; Schramm, Kathrin; Weiss, Ursula; Bading, Hilmar

    2015-09-18

    Calcium-binding proteins (CaBPs) such as parvalbumin are part of the cellular calcium buffering system that determines intracellular calcium diffusion and influences the spatiotemporal dynamics of calcium signals. In neurons, CaBPs are primarily localized to the cytosol and function, for example, in nerve terminals in short-term synaptic plasticity. However, CaBPs are also expressed in the cell nucleus, suggesting that they modulate nuclear calcium signals, which are key regulators of neuronal gene expression. Here we show that the calcium buffering capacity of the cell nucleus in mouse hippocampal neurons regulates neuronal architecture by modulating the expression levels of VEGFD and the complement factor C1q-c, two nuclear calcium-regulated genes that control dendrite geometry and spine density, respectively. Increasing the levels of nuclear calcium buffers by means of expression of a nuclearly targeted form of parvalbumin fused to mCherry (PV.NLS-mC) led to a reduction in VEGFD expression and, as a result, to a decrease in total dendritic length and complexity. In contrast, mRNA levels of the synapse pruning factor C1q-c were increased in neurons expressing PV.NLS-mC, causing a reduction in the density and size of dendritic spines. Our results establish a close link between nuclear calcium buffering capacity and the transcription of genes that determine neuronal structure. They suggest that the development of cognitive deficits observed in neurological conditions associated with CaBP deregulation may reflect the loss of necessary structural features of dendrites and spines. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. The group VIA calcium-independent phospholipase A2 and NFATc4 pathway mediates IL-1β-induced expression of chemokines CCL2 and CXCL10 in rat fibroblasts.

    PubMed

    Kuwata, Hiroshi; Yuzurihara, Chihiro; Kinoshita, Natsumi; Taki, Yuki; Ikegami, Yuki; Washio, Sana; Hirakawa, Yushi; Yoda, Emiko; Aiuchi, Toshihiro; Itabe, Hiroyuki; Nakatani, Yoshihito; Hara, Shuntaro

    2018-06-01

    Chemokines are secreted proteins that regulate cell migration and are involved in inflammatory and immune responses. Here, we sought to define the functional crosstalk between the lipid signaling and chemokine signaling. We obtained evidence that the induction of some chemokines is regulated by group VIA calcium-independent phospholipase A 2 β (iPLA 2 β) in IL-1β-stimulated rat fibroblastic 3Y1 cells. Treatment of 3Y1 cells with IL-1β elicited an increased release of chemotactic factor(s) for monocytic THP-1 cells into culture medium in a time-dependent manner. Inhibitor studies revealed that an intracellular PLA 2 inhibitor, arachidonoyl trifluoromethyl ketone (AACOCF 3 ), but not the cyclooxygenase inhibitor indomethacin, attenuated the release of chemotactic factor(s). The chemotactic activity was inactivated by treatment with either heat or proteinase K, suggesting this chemotactic factor(s) is a proteinaceous factor(s). We purified the chemotactic factor(s) from the conditioned medium of IL-1β-stimulated 3Y1 cells using a heparin column and identified several chemokines, including CCL2 and CXCL10. The inducible expressions of CCL2 and CXCL10 were significantly attenuated by pretreatment with AACOCF 3 . Gene silencing using siRNA revealed that the inductions of CCL2 and CXCL10 were attenuated by iPLA 2 β knockdown. Additionally, the transcriptional activation of nuclear factor of activated T-cell proteins (NFATs), but not nuclear factor-κB, by IL-1β stimulation was markedly attenuated by the iPLA 2 inhibitor bromoenol lactone, and NFATc4 knockdown markedly attenuated the IL-1β-induced expression of both CCL2 and CXCL10. Collectively, these results indicated that iPLA 2 β plays roles in IL-1β-induced chemokine expression, in part via NFATc4 signaling. © 2018 Federation of European Biochemical Societies.

  2. TRIENNIAL LACTATION SYMPOSIUM/BOLFA: Serotonin and the regulation of calcium transport in dairy cows.

    PubMed

    Hernandez, L L

    2017-12-01

    The mammary gland regulates maternal metabolism during lactation. Numerous factors within the tissue send signals to shift nutrients to the mammary gland for milk synthesis. Serotonin is a monoamine that has been well documented to regulate several aspects of lactation among species. Maintenance of maternal calcium homeostasis during lactation is a highly evolved process that is elegantly regulated by the interaction of the mammary gland with the bone, gut, and kidney tissues. It is well documented that dietary calcium is insufficient to maintain maternal calcium concentrations during lactation, and mammals must rely on bone resorption to maintain normocalcemia. Our recent work focused on the ability of the mammary gland to function as an accessory parathyroid gland during lactation. It was demonstrated that serotonin acts to stimulate parathyroid hormone-related protein (PTHrP) in the mammary gland during lactation. The main role of mammary-derived PTHrP during mammalian lactation is to stimulate bone resorption to maintain maternal calcium homeostasis during lactation. In addition to regulating PTHrP, it was shown that serotonin appears to directly affect calcium transporters and pumps in the mammary gland. Our current working hypothesis regarding the control of calcium during lactation is as follows: serotonin directly stimulates PTHrP production in the mammary gland through interaction with the sonic hedgehog signaling pathway. Simultaneously, serotonin directly increases calcium movement into the mammary gland and, subsequently, milk. These 2 direct actions of serotonin combine to induce a transient maternal hypocalcemia required to further stimulate PTHrP production and calcium mobilization from bone. Through these 2 routes, serotonin is able to improve maternal calcium concentrations. Furthermore, we have shown that Holstein and Jersey cows appear to regulate calcium in different manners and also respond differently to serotonergic stimulation of the calcium

  3. Calcium movements during pigment aggregation in freshwater shrimp chromatophores.

    PubMed

    Ribeiro, Márcia; McNamara, John Campbell

    2007-02-01

    Pigment granule migration within crustacean chromatophores provides an excellent model with which to investigate cytoplasmic movements, given the antagonistic, neurosecretory peptide regulation of granule translocation, and the absence of innervation in these large, brightly colored cells. Red pigment-concentrating hormone (RPCH) induces pigment aggregation in shrimp chromatophores via an increase in intracellular Ca2+; however, how this increase is brought about is not known. To examine the putative Ca2+ movements leading to pigment translocation in red, ovarian chromatophores of the freshwater shrimp, Macrobrachium olfersii, this study manipulates intra- and extracellular Ca2+ employing ER Ca2+-ATPase inhibitors, ryanodine-sensitive, ER Ca2+ channel blockers, and EDTA/EGTA-buffered A23187/Ca2+-containing salines. Our findings reveal that during pigment aggregation, cytosolic Ca2+ apparently increases from an intracellular source, the abundant SER, loaded by the SERCA and released through ryanodine-sensitive receptor/channels, triggered by capacitative calcium influx and/or calcium-induced calcium release mechanisms. Aggregation also depends on external calcium, which may modulate RPCH/receptor coupling. Such calcium-regulated pigment movements form the basis of a complex system of chromatic adaptation, which confers selective advantages like camouflage and protection against ultra-violet radiation to this palaemonid shrimp.

  4. N-acetyl-l-cysteine and Mn2+ attenuate Cd2+-induced disturbance of the intracellular free calcium homeostasis in cultured cerebellar granule neurons.

    PubMed

    Isaev, Nickolay K; Avilkina, Svetlana; Golyshev, Sergey A; Genrikhs, Elisaveta E; Alexandrova, Olga P; Kapkaeva, Marina R; Stelmashook, Elena V

    2018-01-15

    Cadmium is a highly toxic heavy metal that is capable of accumulating in the body via direct exposure or through the alimentary and respiratory tract, leading to neurodegeneration. In this article, we show that the application of CdCl 2 (0.001-0.005mM) for 48h induced high dose-dependent death rate of cultured cerebellar granule neurons (CGNs). Unlike Trolox or vitamin E, antioxidant N-acetyl-l-cysteine (NAC, 1mM) and Mn 2+ (0.0025-0.005mM) significantly protected CGNs from this toxic effect. Using Fluo-4 AM, measurements of intracellular calcium ions demonstrated that 24h-exposure to Cd 2+ induced intensive increase of Fluo-4 fluorescence in neurons accompanied by mitochondria swelling. These data imply that the cadmium-induced Ca 2+ increase is an important element in the death of neurons due to toxic effect of cadmium and the mechanism of protective action of manganese and NAC is mediated by the prevention of increase in calcium levels. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Role of Ca2+-independent phospholipase A2 and cytochrome P-450 in store-operated calcium entry in 3T6 fibroblasts.

    PubMed

    Martínez, Javier; Moreno, Juan J

    2005-09-01

    Store-operated calcium (SOC) channels and capacitative Ca2+ entry play a key role in cellular functions, but their mechanism of activation remains unclear. Here, we show that thapsigargin induces [3H] arachidonic acid (AA) release, 45Ca2+ influx and a subsequent enhancement of intracellular calcium concentration ([Ca2+]i. Thapsigargin-induced elevation of [Ca2+]i was inhibited by cytochrome P-450 inhibitors and by cytochrome P-450 epoxygenase inhibitor and was reverted by 11,12 EET addition. However, cyclooxygenase and lipoxygenase inhibitors have no effect. Moreover, we observed that four EETs were able to induce 45Ca2+ influx. Finally, we reported that the effect of 11,12 EET on 45Ca2+ influx was sensible to receptor-operated Ca2+ channel blockers (NiCl2, LaCl3) but not to voltage-dependent Ca2+ channel blocker as verapamil. Thus, AA released by Ca2+-independent phospholipase A2 and AA metabolism through cytochrome P-450 pathway may be crucial molecular determinant in thapsigargin activation of SOC channels and store-operated Ca2+ entry pathway in 3T6 fibroblasts. Moreover, EETs, the main cytochrome P-450 epoxygenase metabolites of AA, are involved in thapsigargin-stimulated Ca2+ influx. In summary, our results suggest that EETs are components of calcium influx factor(s).

  6. Mechanism regulating nuclear calcium signaling.

    PubMed

    Malviya, Anant N; Klein, Christian

    2006-01-01

    Although the outer nuclear membrane is continuous with the endoplasmic reticulum, it is possible to isolate nuclei both intact and free from endoplasmic reticulum contaminants. The outer and the inner nuclear membranes can be purified free from cross-contamination. Evidence in support of autonomous regulation of nuclear calcium signaling relies upon the investigations with isolated nuclei. Mechanisms for generating calcium signaling in the nucleus have been identified. Two calcium transporting systems, an ATP-dependant nuclear Ca(2+)-ATPase and an IP4-mediated inositol 1,3,4,5-tetrakisphosphate receptor, are located on the outer nuclear membrane. Thus, ATP and IP4, depending on external free calcium concentrations, are responsible for filling the nuclear envelope calcium pool. The inositol 1,4,5-trisphosphate receptor is located on the inner nuclear membrane with its ligand binding domain facing toward the nucleoplasm. Likewise, the ryanodine receptor is located on the inner nuclear membrane and its ligand cADP-ribose is generated within the nucleus. A 120 kDa protein fragment of nuclear PLC-gamma1 is stimulated in vivo by epidermal growth factor nuclear signaling coincident with the time course of nuclear membrane epidermal growth factor receptor activation. Stimulated 120 kDa protein fragment interacts with PIKE, a nuclear GTPase, and together they form a complex with PI[3]kinase serving as a module for nuclear PI[3]K stimulation. Thus, the nucleus has its own IP(3) generating system.

  7. Space-flight simulations of calcium metabolism using a mathematical model of calcium regulation

    NASA Technical Reports Server (NTRS)

    Brand, S. N.

    1985-01-01

    The results of a series of simulation studies of calcium matabolic changes which have been recorded during human exposure to bed rest and space flight are presented. Space flight and bed rest data demonstrate losses of total body calcium during exposure to hypogravic environments. These losses are evidenced by higher than normal rates of urine calcium excretion and by negative calcium balances. In addition, intestinal absorption rates and bone mineral content are assumed to decrease. The bed rest and space flight simulations were executed on a mathematical model of the calcium metabolic system. The purpose of the simulations is to theoretically test hypotheses and predict system responses which are occurring during given experimental stresses. In this case, hypogravity occurs through the comparison of simulation and experimental data and through the analysis of model structure and system responses. The model reliably simulates the responses of selected bed rest and space flight parameters. When experimental data are available, the simulated skeletal responses and regulatory factors involved in the responses agree with space flight data collected on rodents. In addition, areas within the model that need improvement are identified.

  8. Impact of calcium intake and intestinal calcium absorption on kidney stones in older women: the study of osteoporotic fractures.

    PubMed

    Sorensen, Mathew D; Eisner, Brian H; Stone, Katie L; Kahn, Arnold J; Lui, Li-Yung; Sadetsky, Natalia; Stoller, Marshall L

    2012-04-01

    Intestinal calcium absorption is thought to have a critical role in nephrolithiasis. However, to our knowledge no study has directly assessed this association. Therefore, we explored the relationship among intestinal fractional calcium absorption, calcium intake and nephrolithiasis. The Study of Osteoporotic Fractures is a prospective cohort of 9,704 postmenopausal women recruited from population based listings in 1986 and followed for more than 20 years. Secondary analyses were performed of 7,982 women who reported their history of nephrolithiasis, of which 5,452 (68%) underwent an oral radioactive calcium assay (45Ca). The impact of dietary and supplemental calcium on intestinal fractional calcium absorption was evaluated, and factors independently associated with nephrolithiasis were determined. Fractional calcium absorption decreased with increased calcium intake, with no difference between dietary and supplemental calcium. Fractional calcium absorption was higher in women with a nephrolithiasis history among all calcium intake groups. Increased dietary calcium intake reduced the likelihood of nephrolithiasis by 45% to 54% (p=0.03). Women with a history of nephrolithiasis were less likely to supplement calcium (p<0.001). In adjusted analyses women who supplemented calcium were 21% to 38% less likely to have a nephrolithiasis history (p=0.007) and there was a 24% increased risk of kidney stones for each 10% increase in fractional calcium absorption (p=0.008). Fractional calcium absorption is higher in women with a history of nephrolithiasis. Higher intestinal fractional calcium absorption is associated with a greater risk of historical nephrolithiasis. Dietary and supplemental calcium decrease fractional calcium absorption, and may protect against nephrolithiasis. Copyright © 2012 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  9. [Effects of intermediate conductance calcium-activated potassium channel blocker TARAM-34 on β-glycerophosphate induced vascular smooth muscle cells calcification].

    PubMed

    Zhang, S L; Xu, J S; Yang, S; Bai, Y L; Zhang, J X; Cui, L W; Yu, Q Y

    2016-06-24

    To observe the role of TRAM-34 (1-((2-chlorophenyl)diphenylmethyl)-1H-pyrazole), the blocker of intermediate conductance calcium-activated potassium channel (KCa3.1), on β-glycerophosphate induced vascular calcification in vitro. Vascular smooth muscle cells(VSMCs) were obtained from rat thoracic aorta, and VSMCs after the fourth passage and aortic rings were divided into control group (cultured in DMEM with 10% fetal bovine serum), high phosphorus group (cultured in DMEM with 10% fetal bovine serum and 10% β-glycerophosphate) and TRAM-34 group(20 nmol/L TRAM-34 was added into high phosphorus DMEM). Calcium deposition of VSMCs and aortic rings were measured by o-cresolphthalein complexone method.Calcium influx of VSMCs was measured by immunofluorescence probe Fluo-3 AM.The expression of runt-related transcription factor 2(Runx2)was detected by RT-PCR and Western blot for cells and immunohistochemistry for aortic rings.ALP activity was measured by alkaline phosphatase activity detection kit. (1) Compared with control group, calcification was significantly increased in high phosphorus group ((121.67±6.17) mg/g vs. (84.38±8.17) mg/g, P<0.05) and this effect could be attenuated by TRAM-34 ((93.31±11.36) mg/g, P<0.05 vs. high phosphorus group) after 12 days culture. Similar results were found in aortic rings cultured for 12 days-high phosphorus group: (7.17±0.57) mg/g vs. (1.18±0.13) mg/g (P<0.05) and TRAM-34: (4.71±0.42) mg/g, P<0.05 vs. high phosphorus group.(2) Compared with control group, the calcium influx was higher in high phosphorus group (349.22±40.47 vs. 151.67±16.94, P<0.05) and reduced in TRAM-34 group (194.67±22.21, P<0.05 vs. high phosphorus group) in VSMCs simulated for 4 days. (3) Both mRNA and protein expressions of Runx2 in high phosphorus groups were higher than in control group (0.630±0.033 vs.0.340±0.058 and 0.865±0.031 vs.0.414±0.011, both P<0.05) and lower in TRAM-34 group (0.399±0.023 and 0.575±0.014, both P<0.05 vs. high

  10. Relation of thoracic aortic and aortic valve calcium to coronary artery calcium and risk assessment.

    PubMed

    Wong, Nathan D; Sciammarella, Maria; Arad, Yadon; Miranda-Peats, Romalisa; Polk, Donna; Hachamovich, Rory; Friedman, John; Hayes, Sean; Daniell, Anthony; Berman, Daniel S

    2003-10-15

    Aortic calcium, aortic valve calcium (AVC), and coronary artery calcium (CAC) have been associated with cardiovascular event risk. We examined the prevalence of thoracic aortic calcium (TAC) and AVC in relation to the presence and extent of CAC, cardiovascular risk factors, and estimated risk of coronary heart disease (CHD). In 2,740 persons without known CHD aged 20 to 79 years, CAC was assessed by electron beam- or multidetector-computed tomography. We determined the prevalence of TAC and AVC in relation to CAC, CHD risk factors, and predicted 10-year risk of CHD. A close correspondence of TAC and AVC was observed with CAC. TAC and AVC increased with age; by the eighth decade of life, the prevalence of TAC was similar to that of CAC (>80%), and 36% of men and 24% of women had AVC. Age, male gender, and low-density lipoprotein cholesterol were directly related to the likelihood of CAC, TAC, and AVC; higher diastolic blood pressure and cigarette smoking additionally predicted CAC. Body mass index and higher systolic and lower diastolic blood pressures were also related to TAC, and higher body mass index and lower diastolic blood pressure were related to AVC. Calculated risk of CHD increased with the presence of AVC and TAC across levels of CAC. TAC and AVC provided incremental value over CAC in association with the 10-year calculated risk of CHD. If longitudinal studies show an incremental value of aortic and aortic valve calcium over that of CAC for prediction of cardiovascular events, future guidelines for risk assessment incorporating CAC assessment may additionally incorporate the measurement of aortic and/or aortic valve calcium.

  11. Carbon monoxide releasing molecule induces endothelial nitric oxide synthase activation through a calcium and phosphatidylinositol 3-kinase/Akt mechanism.

    PubMed

    Yang, Po-Min; Huang, Yu-Ting; Zhang, Yu-Qi; Hsieh, Chia-Wen; Wung, Being-Sun

    2016-12-01

    The production of nitric oxide (NO) by endothelial NO synthase (eNOS) plays a major role in maintaining vascular homeostasis. This study elucidated the potential role of carbon monoxide (CO)-releasing molecules (CORMs) in NO production and explored the underlying mechanisms in endothelial cells. We observed that 25μM CORM-2 could increase NO production and stimulate an increase in the intracellular Ca 2+ level. Furthermore, ethylene glycol-bis(β-aminoethyl ether)-N,N,N',N'-tetra acetic acid caused CORM-2-induced NO production, which was abolished by 1,2-bis(2-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid tetraacetoxy-methyl ester (BAPTA-AM), indicating that intracellular Ca 2+ release plays a major role in eNOS activation. The inhibition of the IP3 receptor diminished the CORM-2-induced intracellular Ca 2+ increase and NO production. Furthermore, CORM-2 induced eNOS Ser 1179 phosphorylation and eNOS dimerization, but it did not alter eNOS expression. CORM-2 (25μM) also prolonged Akt phosphorylation, lasting for at least 12h. Pretreatment with phosphatidylinositol 3-kinase inhibitors (wortmannin or LY294002) inhibited the increases in NO production and phosphorylation but did not affect eNOS dimerization. CORM-2-induced eNOS Ser 1179 phosphorylation was intracellularly calcium-dependent, because pretreatment with an intracellular Ca 2+ chelator (BAPTA-AM) inhibited this process. Although CORM-2 increases intracellular reactive oxygen species (ROS), pretreatment with antioxidant enzyme catalase and N-acetyl-cysteine did not abolish the CORM-2-induced eNOS activity or phosphorylation, signifying that ROS is not involved in this activity. Hence, CORM-2 enhances eNOS activation through intracellular calcium release, Akt phosphorylation, and eNOS dimerization. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Dependency of Calcium Alternans on Ryanodine Receptor Refractoriness

    PubMed Central

    Alvarez-Lacalle, Enric; Cantalapiedra, Inma R.; Peñaranda, Angelina; Cinca, Juan; Hove-Madsen, Leif; Echebarria, Blas

    2013-01-01

    Background Rapid pacing rates induce alternations in the cytosolic calcium concentration caused by fluctuations in calcium released from the sarcoplasmic reticulum (SR). However, the relationship between calcium alternans and refractoriness of the SR calcium release channel (RyR2) remains elusive. Methodology/Principal Findings To investigate how ryanodine receptor (RyR2) refractoriness modulates calcium handling on a beat-to-beat basis using a numerical rabbit cardiomyocyte model. We used a mathematical rabbit cardiomyocyte model to study the beat-to-beat calcium response as a function of RyR2 activation and inactivation. Bi-dimensional maps were constructed depicting the beat-to-beat response. When alternans was observed, a novel numerical clamping protocol was used to determine whether alternans was caused by oscillations in SR calcium loading or by RyR2 refractoriness. Using this protocol, we identified regions of RyR2 gating parameters where SR calcium loading or RyR2 refractoriness underlie the induction of calcium alternans, and we found that at the onset of alternans both mechanisms contribute. At low inactivation rates of the RyR2, calcium alternans was caused by alternation in SR calcium loading, while at low activation rates it was caused by alternation in the level of available RyR2s. Conclusions/Significance We have mapped cardiomyocyte beat-to-beat responses as a function of RyR2 activation and inactivation, identifying domains where SR calcium load or RyR2 refractoriness underlie the induction of calcium alternans. A corollary of this work is that RyR2 refractoriness due to slow recovery from inactivation can be the cause of calcium alternans even when alternation in SR calcium load is present. PMID:23390511

  13. Sleep-inducing factors.

    PubMed

    García-García, Fabio; Acosta-Peña, Eva; Venebra-Muñoz, Arturo; Murillo-Rodríguez, Eric

    2009-08-01

    Kuniomi Ishimori and Henri Piéron were the first researchers to introduce the concept and experimental evidence for a chemical factor that would presumably accumulate in the brain during waking and eventually induce sleep. This substance was named hypnotoxin. Currently, the variety of substances which have been shown to alter sleep includes peptides, cytokines, neurotransmitters and some substances of lipidic nature, many of which are well known for their involvement in other biological activities. In this chapter, we describe the sleep-inducing properties of the vasoactive intestinal peptide, prolactin, adenosine and anandamide.

  14. Calcium signaling properties of a thyrotroph cell line, mouse TαT1 cells.

    PubMed

    Tomić, Melanija; Bargi-Souza, Paula; Leiva-Salcedo, Elias; Nunes, Maria Tereza; Stojilkovic, Stanko S

    2015-12-01

    TαT1 cells are mouse thyrotroph cell line frequently used for studies on thyroid-stimulating hormone beta subunit gene expression and other cellular functions. Here we have characterized calcium-signaling pathways in TαT1 cells, an issue not previously addressed in these cells and incompletely described in native thyrotrophs. TαT1 cells are excitable and fire action potentials spontaneously and in response to application of thyrotropin-releasing hormone (TRH), the native hypothalamic agonist for thyrotrophs. Spontaneous electrical activity is coupled to small amplitude fluctuations in intracellular calcium, whereas TRH stimulates both calcium mobilization from intracellular pools and calcium influx. Non-receptor-mediated depletion of intracellular pool also leads to a prominent facilitation of calcium influx. Both receptor and non-receptor stimulated calcium influx is substantially attenuated but not completely abolished by inhibition of voltage-gated calcium channels, suggesting that depletion of intracellular calcium pool in these cells provides a signal for both voltage-independent and -dependent calcium influx, the latter by facilitating the pacemaking activity. These cells also express purinergic P2Y1 receptors and their activation by extracellular ATP mimics TRH action on calcium mobilization and influx. The thyroid hormone triiodothyronine prolongs duration of TRH-induced calcium spikes during 30-min exposure. These data indicate that TαT1 cells are capable of responding to natively feed-forward TRH signaling and intrapituitary ATP signaling with acute calcium mobilization and sustained calcium influx. Amplification of TRH-induced calcium signaling by triiodothyronine further suggests the existence of a pathway for positive feedback effects of thyroid hormones probably in a non-genomic manner. Published by Elsevier Ltd.

  15. Increased LDL electronegativity in chronic kidney disease disrupts calcium homeostasis resulting in cardiac dysfunction.

    PubMed

    Chang, Kuan-Cheng; Lee, An-Sheng; Chen, Wei-Yu; Lin, Yen-Nien; Hsu, Jing-Fang; Chan, Hua-Chen; Chang, Chia-Ming; Chang, Shih-Sheng; Pan, Chia-Chi; Sawamura, Tatsuya; Chang, Chi-Tzong; Su, Ming-Jai; Chen, Chu-Huang

    2015-07-01

    Chronic kidney disease (CKD), an independent risk factor for cardiovascular disease, is associated with abnormal lipoprotein metabolism. We examined whether electronegative low-density lipoprotein (LDL) is mechanistically linked to cardiac dysfunction in patients with early CKD. We compared echocardiographic parameters between patients with stage 2 CKD (n = 88) and normal controls (n = 89) and found that impaired relaxation was more common in CKD patients. Reduction in estimated glomerular filtration rate was an independent predictor of left ventricular relaxation dysfunction. We then examined cardiac function in a rat model of early CKD induced by unilateral nephrectomy (UNx) by analyzing pressure-volume loop data. The time constant of isovolumic pressure decay was longer and the maximal velocity of pressure fall was slower in UNx rats than in controls. When we investigated the mechanisms underlying relaxation dysfunction, we found that LDL from CKD patients and UNx rats was more electronegative than LDL from their respective controls and that LDL from UNx rats induced intracellular calcium overload in H9c2 cardiomyocytes in vitro. Furthermore, chronic administration of electronegative LDL, which signals through lectin-like oxidized LDL receptor-1 (LOX-1), induced relaxation dysfunction in wild-type but not LOX-1(-/-) mice. In in vitro and in vivo experiments, impaired cardiac relaxation was associated with increased calcium transient resulting from nitric oxide (NO)-dependent nitrosylation of SERCA2a due to increases in inducible NO synthase expression and endothelial NO synthase uncoupling. In conclusion, LDL becomes more electronegative in early CKD. This change disrupts SERCA2a-regulated calcium homeostasis, which may be the mechanism underlying cardiorenal syndrome. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Analysis of Spontaneous and Nerve-Evoked Calcium Transients in Intact Extraocular Muscles in Vitro

    PubMed Central

    Feng, Cheng-Yuan; Hennig, Grant W.; Corrigan, Robert D.; Smith, Terence K.; von Bartheld, Christopher S.

    2012-01-01

    Extraocular muscles (EOMs) have unique calcium handling properties, yet little is known about the dynamics of calcium events underlying ultrafast and tonic contractions in myofibers of intact EOMs. Superior oblique EOMs of juvenile chickens were dissected with their nerve attached, maintained in oxygenated Krebs buffer, and loaded with fluo-4. Spontaneous and nerve stimulation-evoked calcium transients were recorded and, following calcium imaging, some EOMs were double-labeled with rhodamine-conjugated alpha-bungarotoxin (rhBTX) to identify EOM myofiber types. EOMs showed two main types of spontaneous calcium transients, one slow type (calcium waves with 1/2max duration of 2–12 s, velocity of 25–50 μm/s) and two fast “flash-like” types (Type 1, 30–90 ms; Type 2, 90–150 ms 1/2max duration). Single pulse nerve stimulation evoked fast calcium transients identical to the fast (Type 1) calcium transients. Calcium waves were accompanied by a local myofiber contraction that followed the calcium transient wavefront. The magnitude of calcium-wave induced myofiber contraction far exceeded those of movement induced by nerve stimulation and associated fast calcium transients. Tetrodotoxin eliminated nerve-evoked transients, but not spontaneous transients. Alpha-bungarotoxin eliminated both spontaneous and nerve-evoked fast calcium transients, but not calcium waves, and caffeine increased wave activity. Calcium waves were observed in myofibers lacking spontaneous or evoked fast transients, suggestive of multiply-innervated myofibers, and this was confirmed by double-labeling with rhBTX. We propose that the abundant spontaneous calcium transients and calcium waves with localized contractions that do not depend on innervation may contribute to intrinsic generation of tonic functions of EOMs. PMID:22579493

  17. Elemental calcium intake associated with calcium acetate/calcium carbonate in the treatment of hyperphosphatemia

    PubMed Central

    Wilson, Rosamund J; Copley, J Brian

    2017-01-01

    Background Calcium-based and non-calcium-based phosphate binders have similar efficacy in the treatment of hyperphosphatemia; however, calcium-based binders may be associated with hypercalcemia, vascular calcification, and adynamic bone disease. Scope A post hoc analysis was carried out of data from a 16-week, Phase IV study of patients with end-stage renal disease (ESRD) who switched to lanthanum carbonate monotherapy from baseline calcium acetate/calcium carbonate monotherapy. Of the intent-to-treat population (N=2520), 752 patients with recorded dose data for calcium acetate (n=551)/calcium carbonate (n=201) at baseline and lanthanum carbonate at week 16 were studied. Elemental calcium intake, serum phosphate, corrected serum calcium, and serum intact parathyroid hormone levels were analyzed. Findings Of the 551 patients with calcium acetate dose data, 271 (49.2%) had an elemental calcium intake of at least 1.5 g/day at baseline, and 142 (25.8%) had an intake of at least 2.0 g/day. Mean (95% confidence interval [CI]) serum phosphate levels were 6.1 (5.89, 6.21) mg/dL at baseline and 6.2 (6.04, 6.38) mg/dL at 16 weeks; mean (95% CI) corrected serum calcium levels were 9.3 (9.16, 9.44) mg/dL and 9.2 (9.06, 9.34) mg/dL, respectively. Of the 201 patients with calcium carbonate dose data, 117 (58.2%) had an elemental calcium intake of at least 1.5 g/day, and 76 (37.8%) had an intake of at least 2.0 g/day. Mean (95% CI) serum phosphate levels were 5.8 (5.52, 6.06) mg/dL at baseline and 5.8 (5.53, 6.05) mg/dL at week 16; mean (95% CI) corrected serum calcium levels were 9.7 (9.15, 10.25) mg/dL and 9.2 (9.06, 9.34) mg/dL, respectively. Conclusion Calcium acetate/calcium carbonate phosphate binders, taken to control serum phosphate levels, may result in high levels of elemental calcium intake. This may lead to complications related to calcium balance. PMID:28182142

  18. Calcium signal communication in the central nervous system.

    PubMed

    Braet, Katleen; Cabooter, Liesbet; Paemeleire, Koen; Leybaert, Luc

    2004-02-01

    The communication of calcium signals between cells is known to be operative between neurons where these signals integrate intimately with electrical and chemical signal communication at synapses. Recently, it has become clear that glial cells also exchange calcium signals between each other in cultures and in brain slices. This communication pathway has received utmost attention since it is known that astrocytic calcium signals can be induced by neuronal stimulation and can be communicated back to the neurons to modulate synaptic transmission. In addition to this, cells that are generally not considered as brain cells become progressively incorporated in the picture, as astrocytic calcium signals are reported to be communicated to endothelial cells of the vessel wall and can affect smooth muscle cell tone to influence the vessel diameter and thus blood flow. We review the available evidence for calcium signal communication in the central nervous system, taking into account a basic functional unit -the brain cell tripartite- consisting of neurons, glial cells and vascular cells and with emphasis on glial-vascular calcium signaling aspects.

  19. Calcium and bone health in children: a review.

    PubMed

    Stallings, V A

    1997-01-01

    The recent national survey shows that dietary calcium intake is variable in children and adolescents, with about half consuming less than the intake recommended by the Recommended Dietary Allowances or the National Institutes of Health Consensus Panel on Optimal Calcium Intake. Osteoporosis is a major disease in adults, resulting in 1.5 million fractures and over $10 billion in medical expenditures annually. Osteoporosis is of growing interest in the research, public health, and health consumer-lay communities and to the many primary care and specialty physicians and other health care professionals who work directly with patients with osteoporosis. Treatment of osteoporosis to prevent fracture is improving with newly introduced medications and approaches, but it is not as effective as needed. Effective prevention strategies are critical to decreasing the morbidity and mortality of the disease. Peak bone mass, obtained during childhood and adolescent growth, is one of the major determinants for the risk of developing osteoporosis and fracture. Genetic potential, gender, ethnic origins, nutritional factors such as calcium and vitamin D intake, growth patterns, and physical activity influence the accretion of bone mineral during childhood and determine the peak bone mass. Randomized, placebo-controlled intervention trials conducted in healthy children who are consuming amounts of dietary calcium in accordance with the US recommendations show that bone mass can be increased by calcium supplementation. Retrospective studies in adults suggest that childhood calcium intake is associated with risk of later osteoporosis and fracture. In addition, common childhood clinical conditions, such as low calcium intake related to lactose intolerance or the use of glucocorticoid medications for chronic illness, are risk factors for the development of osteoporosis in childhood, not just in adulthood. An approach for physicians and other pediatric care providers for screening children

  20. Desalted Duck Egg White Peptides Promote Calcium Uptake and Modulate Bone Formation in the Retinoic Acid-Induced Bone Loss Rat and Caco-2 Cell Model.

    PubMed

    Hou, Tao; Liu, Yanshuang; Kolba, Nikolai; Guo, Danjun; He, Hui

    2017-05-12

    Desalted duck egg white peptides (DPs) have been proven to promote calcium uptake in Caco-2 cells and rats treated with a calcium-deficient diet. The retinoic acid-induced bone loss model was used to evaluate the effect of DPs on calcium absorption and bone formation. Three-month-old Wistar female rats were treated with 0.9% saline, DPs (800 mg/kg), or alendronate (5 mg/kg) for three weeks immediately after retinoic acid treatment (80 mg/kg) once daily for two weeks. The model group was significantly higher in serum bone alkaline phosphatase than the other three groups ( p < 0.05), but lower in calcium absorption rate, serum osteocalcin, bone weight index, bone calcium content, bone mineral density, and bone max load. After treatment with DPs or alendronate, the absorption rate increased and some serum and bone indices recovered. The morphology results indicated bone tissue form were ameliorated and numbers of osteoclasts decreased after supplementation with DPs or alendronate. The in vitro study showed that the transient receptor potential vanilloid 6 (TRPV6) calcium channel was the main transport pathway of both DPs and Val-Ser-Glu-Glu peptitde (VSEE), which was identified from DPs. Our results indicated that DPs could be a promising alternative to current therapeutic agents for bone loss because of the promotion of calcium uptake and regulation of bone formation.

  1. Nuclear Membranes ETB Receptors Mediate ET-1-induced Increase of Nuclear Calcium in Human Left Ventricular Endocardial Endothelial Cells.

    PubMed

    Jules, Farah; Avedanian, Levon; Al-Khoury, Johny; Keita, Ramatoulaye; Normand, Alexandre; Bkaily, Ghassan; Jacques, Danielle

    2015-07-01

    In fetal human left ventricular endocardial endothelial cells (EECLs), both plasma membrane (PM) ET(A)R and ET(B)R were reported to mediate ET-1-induced increase of intracellular calcium [Ca](i); however, this effect was mediated by ET(A)R in right EECs (EECRs). In this study, we verified whether, as for the PM, nuclear membranes (NMs) ET-1 receptors activation in EECLs and EECRs induce an increase of nuclear calcium ([Ca](n)) and if this effect is mediated through the same receptor type as in PM. Using a plasmalemma-perforated technique and 3D confocal microscopy, our results showed that, as in PM intact cells, superfusion of nuclei of both cell types with cytosolic ET-1 induced a concentration-dependent sustained increase of [Ca](n). In EECRs, the ET(A)R antagonist prevented the effect of ET-1 on [Ca](n) without affecting EECLs. However, in both cell types, the effect of cytosolic ET-1 on [Ca](n) was prevented by the ETBR antagonist. In conclusion, both NMs' ET(A)R and ET(B)R mediated the effect of cytosolic ET-1 on [Ca](n) in EECRs. In contrast, only NMs' ET(B)R activation mediated the effect of cytosolic ET-1 in EECLs. Hence, the type of NMs' receptors mediating the effect of ET-1 on [Ca](n) are different from those of PM mediating the increase in [Ca](i).

  2. Ionotropic and Metabotropic Mechanisms of Allosteric Modulation of α7 Nicotinic Receptor Intracellular Calcium.

    PubMed

    King, Justin R; Ullah, Aman; Bak, Ellen; Jafri, M Saleet; Kabbani, Nadine

    2018-06-01

    The pharmacological targeting of the α 7 nicotinic acetylcholine receptor ( α 7) is a promising strategy in the development of new drugs for neurologic diseases. Because α 7 receptors regulate cellular calcium, we investigated how the prototypical type II-positive allosteric modulator PNU120596 affects α 7-mediated calcium signaling. Live imaging experiments show that PNU120596 augments ryanodine receptor-driven calcium-induced calcium release (CICR), inositol-induced calcium release (IICR), and phospholipase C activation by the α 7 receptor. Both influx of calcium through the α 7 nicotinic acetylcholine receptor (nAChR) channel as well as the binding of intracellular G proteins were involved in the effect of PNU120596 on intracellular calcium. This is evidenced by the findings that chelation of extracellular calcium, expression of α 7 D44A or α 7 345-348A mutant subunits, or blockade of calcium store release compromised the ability of PNU120596 to increase intracellular calcium transients generated by α 7 ligand activation. Spatiotemporal stochastic modeling of calcium transient responses corroborates these results and indicates that α 7 receptor activation enables calcium microdomains locally and to lesser extent in the distant cytosol. From the model, allosteric modulation of the receptor activates CICR locally via ryanodine receptors and augments IICR through enhanced calcium influx due to prolonged α 7 nAChR opening. These findings provide a new mechanistic framework for understanding the effect of α 7 receptor allosteric modulation on both local and global calcium dynamics. Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.

  3. Mammary-Specific Ablation of the Calcium-Sensing Receptor During Lactation Alters Maternal Calcium Metabolism, Milk Calcium Transport, and Neonatal Calcium Accrual

    PubMed Central

    Mamillapalli, Ramanaiah; VanHouten, Joshua; Dann, Pamela; Bikle, Daniel; Chang, Wenhan; Brown, Edward

    2013-01-01

    To meet the demands for milk calcium, the lactating mother adjusts systemic calcium and bone metabolism by increasing dietary calcium intake, increasing bone resorption, and reducing renal calcium excretion. As part of this adaptation, the lactating mammary gland secretes PTHrP into the maternal circulation to increase bone turnover and mobilize skeletal calcium stores. Previous data have suggested that, during lactation, the breast relies on the calcium-sensing receptor (CaSR) to coordinate PTHrP secretion and milk calcium transport with calcium availability. To test this idea genetically, we bred BLG-Cre mice with CaSR-floxed mice to ablate the CaSR specifically from mammary epithelial cells only at the onset of lactation (CaSR-cKO mice). Loss of the CaSR in the lactating mammary gland did not disrupt alveolar differentiation or milk production. However, it did increase the secretion of PTHrP into milk and decreased the transport of calcium from the circulation into milk. CaSR-cKO mice did not show accelerated bone resorption, but they did have a decrease in bone formation. Loss of the mammary gland CaSR resulted in hypercalcemia, decreased PTH secretion, and increased renal calcium excretion in lactating mothers. Finally, loss of the mammary gland CaSR resulted in decreased calcium accrual by suckling neonates, likely due to the combination of increased milk PTHrP and decreased milk calcium. These results demonstrate that the mammary gland CaSR coordinates maternal bone and calcium metabolism, calcium transport into milk, and neonatal calcium accrual during lactation. PMID:23782944

  4. Osteocyte-derived RANKL is a critical mediator of the increased bone resorption caused by dietary calcium deficiency

    PubMed Central

    Xiong, Jinhu; Piemontese, Marilina; Thostenson, Jeff D.; Weinstein, Robert S.; Manolagas, Stavros C.; O’Brien, Charles A.

    2014-01-01

    Parathyroid hormone (PTH) excess stimulates bone resorption. This effect is associated with increased expression of the osteoclastogenic cytokine receptor activator of nuclear factor кB ligand (RANKL) in bone. However, several different cell types, including bone marrow stromal cells, osteocytes, and T lymphocytes, express both RANKL and the PTH receptor and it is unclear whether RANKL expression by any of these cell types is required for PTH-induced bone loss. Here we have used mice lacking the RANKL gene in osteocytes to determine whether RANKL produced by this cell type is required for the bone loss caused by secondary hyperparathyroidism induced by dietary calcium deficiency in adult mice. Thirty days of dietary calcium deficiency caused bone loss in control mice, but this effect was blunted in mice lacking RANKL in osteocytes. The increase in RANKL expression in bone and the increase in osteoclast number caused by dietary calcium deficiency were also blunted in mice lacking RANKL in osteocytes. These results demonstrate that RANKL produced by osteocytes contributes to the increased bone resorption and the bone loss caused by secondary hyperparathyroidism, strengthening the evidence that osteocytes are an important target cell for hormonal control of bone remodeling. PMID:24933342

  5. Is excess calcium harmful to health?

    PubMed

    Daly, Robin M; Ebeling, Peter R

    2010-05-01

    Most current guidelines recommend that older adults and the elderly strive for a total calcium intake (diet and supplements) of 1,000 to 1,300 mg/day to prevent osteoporosis and fractures. Traditionally, calcium supplements have been considered safe, effective and well tolerated, but their safety has recently been questioned due to potential adverse effects on vascular disease which may increase mortality. For example, the findings from a meta-analysis of randomized controlled trials (currently published in abstract form only) revealed that the use of calcium supplements was associated with an ~30% increased risk of myocardial infarction. If high levels of calcium are harmful to health, this may alter current public health recommendations with regard to the use of calcium supplements for preventing osteoporosis. In this review, we provide an overview of the latest information from human observational and prospective studies, randomized controlled trials and meta-analyses related to the effects of calcium supplementation on vascular disease and related risk factors, including blood pressure, lipid and lipoprotein levels and vascular calcification.

  6. Is Excess Calcium Harmful to Health?

    PubMed Central

    Daly, Robin M.; Ebeling, Peter R.

    2010-01-01

    Most current guidelines recommend that older adults and the elderly strive for a total calcium intake (diet and supplements) of 1,000 to 1,300 mg/day to prevent osteoporosis and fractures. Traditionally, calcium supplements have been considered safe, effective and well tolerated, but their safety has recently been questioned due to potential adverse effects on vascular disease which may increase mortality. For example, the findings from a meta-analysis of randomized controlled trials (currently published in abstract form only) revealed that the use of calcium supplements was associated with an ~30% increased risk of myocardial infarction. If high levels of calcium are harmful to health, this may alter current public health recommendations with regard to the use of calcium supplements for preventing osteoporosis. In this review, we provide an overview of the latest information from human observational and prospective studies, randomized controlled trials and meta-analyses related to the effects of calcium supplementation on vascular disease and related risk factors, including blood pressure, lipid and lipoprotein levels and vascular calcification. PMID:22254038

  7. Inhibition of endogenous heat shock protein 70 attenuates inducible nitric oxide synthase induction via disruption of heat shock protein 70/Na(+) /H(+) exchanger 1-Ca(2+) -calcium-calmodulin-dependent protein kinase II/transforming growth factor β-activated kinase 1-nuclear factor-κB signals in BV-2 microglia.

    PubMed

    Huang, Chao; Lu, Xu; Wang, Jia; Tong, Lijuan; Jiang, Bo; Zhang, Wei

    2015-08-01

    Inducible nitric oxide synthase (iNOS) critically contributes to inflammation and host defense. The inhibition of heat shock protein 70 (Hsp70) prevents iNOS induction in lipopolysaccharide (LPS)-stimulated macrophages. However, the role and mechanism of endogenous Hsp70 in iNOS induction in microglia remains unclear. This study addresses this issue in BV-2 microglia, showing that Hsp70 inhibition or knockdown prevents LPS-induced iNOS protein expression and nitric oxide production. Real-time PCR experiments showed that LPS-induced iNOS mRNA transcription was blocked by Hsp70 inhibition. Further studies revealed that the inhibition of Hsp70 attenuated LPS-stimulated nuclear translocation and phosphorylation of nuclear factor (NF)-κB as well as the degradation of inhibitor of κB (IκB)-α and phosphorylation of IκB kinase β (IKKβ). This prevention effect of Hsp70 inhibition on IKKβ-NF-κB activation was found to be dependent on the Ca(2+) /calcium-calmodulin-dependent protein kinase II (CaMKII)/transforming growth factor β-activated kinase 1 (TAK1) signals based on the following observations: 1) chelation of intracellular Ca(2+) or inhibition of CaMKII reduced LPS-induced increases in TAK1 phosphorylation and 2) Hsp70 inhibition reduced LPS-induced increases in CaMKII/TAK1 phosphorylation, intracellular pH value, [Ca(2+) ]i , and CaMKII/TAK1 association. Mechanistic studies showed that Hsp70 inhibition disrupted the association between Hsp70 and Na(+) /H(+) exchanger 1 (NHE1), which is an important exchanger responsible for Ca(2+) influx in LPS-stimulated cells. These studies demonstrate that the inhibition of endogenous Hsp70 attenuates the induction of iNOS, which likely occurs through the disruption of NHE1/Hsp70-Ca(2+) -CaMKII/TAK1-NF-κB signals in BV-2 microglia, providing further insight into the functions of Hsp70 in the CNS. © 2015 Wiley Periodicals, Inc.

  8. Impact of Calcium Intake and Intestinal Calcium Absorption on Kidney Stones in Older Women: The Study of Osteoporotic Fractures (SOF)

    PubMed Central

    Sorensen, Mathew D.; Eisner, Brian H.; Stone, Katie L.; Kahn, Arnold J.; Lui, Li-Yung; Sadetsky, Natalia; Stoller, Marshall L.

    2013-01-01

    Purpose Intestinal calcium absorption is thought to play a critical role in nephrolithiasis; however, no study has directly assessed this association. The purpose of this study was to explore the relationship between intestinal fractional calcium absorption, calcium intake, and nephrolithiasis. Materials and Methods The Study of Osteoporotic Fractures is a prospective cohort of 9704 post-menopausal women recruited from population-based listings in 1986 and followed for more than 20 years. Secondary analyses were performed of 7982 women who reported their history of nephrolithiasis, of which 5452 (68%) underwent oral radioactive calcium assay (45Ca). The impact of dietary and supplemental calcium on intestinal fractional calcium absorption was evaluated and factors independently associated with nephrolithiasis were determined. Results Fractional calcium absorption decreased with increased calcium intake, with no difference between dietary and supplemental calcium. Fractional calcium absorption was higher in women with a nephrolithiasis history among all calcium intake groups. Increased dietary calcium intake reduced the likelihood of nephrolithiasis by 45–54% (p=0.03). Women with a history of nephrolithiasis were less likely to supplement calcium (p<0.001). In adjusted analyses, women who supplemented calcium were 21–38% less likely to have a nephrolithiasis history (p=0.007) and there was a 24% increased risk of kidney stones for each 10% increase in fractional calcium absorption (p=0.008). Conclusions Fractional calcium absorption is higher in women with a history of nephrolithiasis. Higher intestinal fractional calcium absorption is associated with a greater risk of historic nephrolithiasis. Dietary and supplemental calcium decrease fractional calcium absorption and may protect against nephrolithiasis. PMID:22341269

  9. From Milk to Bones, Moving Calcium Through the Body: Calcium Kinetics During Space Flight

    NASA Technical Reports Server (NTRS)

    Smith, Scott; Bloomberg, Jacob; Lee, Angie (Technical Monitor)

    2002-01-01

    Did you know that when astronauts are in space, their height increases about two inches? This happens because the weightlessness of space allows the spine, usually compressed in Earth's gravity, to expand. While this change is relatively harmless, other more serious things can happen with extended stays in weightlessness, notably bone loss. From previous experiments, scientists have observed that astronauts lose bone mass at a rate of about one percent per month during flight. Scientists know that bone is a dynamic tissue - continually being made and repaired by specialized bone cells throughout life. Certain cells produce new bone, while other cells are responsible for removing and replacing old bone. Research on the mechanisms of bone metabolism and the effects of space flight on its formation and repair are part of the exciting studies that will be performed during STS-107. Calcium plays a central role because 1) it gives strength and structure to bone and 2) all types of cells require it to function normally. Ninety-nine percent of calcium in the body is stored in the skeleton. However, calcium may be released, or resorbed, from bone to provide for other tissues when you are not eating. To better understand how and why weightlessness induces bone loss, astronauts will participate in a study of calcium kinetics - that is, the movement of calcium through the body, including absorption from food, and its role in the formation and breakdown of bone.

  10. PYK2: A Calcium-sensitive Protein Tyrosine Kinase Activated in Response to Fertilization of the Zebrafish Oocyte

    PubMed Central

    Sharma, Dipika; Kinsey, William H.

    2012-01-01

    Fertilization begins with binding and fusion of a sperm with the oocyte, a process that triggers a high amplitude calcium transient which propagates through the oocyte and stimulates a series of preprogrammed signal transduction events critical for zygote development. Identification of the pathways downstream of this calcium transient remains an important step in understanding the basis of zygote quality. The present study demonstrates that the calcium-calmodulin sensitive protein tyrosine kinase PYK2 is a target of the fertilization-induced calcium transient in the zebrafish oocyte and that it plays an important role in actin-mediated events critical for sperm incorporation. At fertilization, PYK2 was activated initially at the site of sperm-oocyte interaction and was closely associated with actin filaments forming the fertilization cone. Later PYK2 activation was evident throughout the entire oocyte cortex, however activation was most intense over the animal hemisphere. Fertilization-induced PYK2 activation could be blocked by suppressing calcium transients in the ooplasm via injection of BAPTA as a calcium chelator. PYK2 activation could be artificially induced in unfertilized oocytes by injection of IP3 at concentrations sufficient to induce calcium release. Functionally, suppression of PYK2 activity by chemical inhibition or by injection of a dominant-negative construct encoding the N-terminal ERM domain of PKY2 inhibited formation of an organized fertilization cone and reduced the frequency of successful sperm incorporation. Together, the above findings support a model in which PYK2 responds to the fertilization-induced calcium transient by promoting reorganization of the cortical actin cytoskeleton to form the fertilization cone. PMID:23084926

  11. Prostaglandins induce vascular endothelial growth factor in a human monocytic cell line and rat lungs via cAMP.

    PubMed

    Höper, M M; Voelkel, N F; Bates, T O; Allard, J D; Horan, M; Shepherd, D; Tuder, R M

    1997-12-01

    Prostaglandins have emerged as a therapeutic option for patients with peripheral vascular disease as well as pulmonary hypertension as a means to increase blood flow. We tested the hypothesis that prostaglandins regulate vascular endothelial growth factor (VEGF) expression in the human monocytic THP-1 cell line and in isolated perfused rat lungs. Our data show that the stable PGI2-analogue iloprost induces VEGF gene expression (predominantly VEGF121, but also VEGF165 isoforms) and VEGF protein synthesis in THP-1 cells. This effect is abolished by dexamethasone and by Rp-cAMP, a specific inhibitor of cAMP-dependent protein kinase (PKA) activation. The calcium channel blocker diltiazem has no effect on the iloprost-induced VEGF gene expression, and depletion of intracellular Ca2+ stores by long-term exposure (16 h) of THP-1 cells to thapsigargin does not inhibit iloprost-induced VEGF gene expression, suggesting that an increase in intracellular Ca2+ is not essential for VEGF gene induction by iloprost. However, an increase of intracellular Ca2+ by a short-term (2 h) exposure of THP-1 cells to thapsigargin or to the calcium-ionophore A23187 increases VEGF mRNA levels, indicating that a change in intracellular Ca2+ by itself can alter VEGF gene expression. The effects of thapsigargin or A23187 on VEGF gene expression are also mediated via cAMP-PKA since they are inhibited by Rp-cAMP. In isolated perfused rat lungs, PGI2 and PGE2 increases VEGF mRNA abundance whereas Rp-cAMP inhibits the prostaglandin-induced VEGF gene activation. Thus, our data suggest that prostaglandins stimulate VEGF gene expression in monocytic cells and in rat lungs via a cAMP-dependent mechanism.

  12. Shear stress-induced calcium transients in endothelial cells from human umbilical cord veins.

    PubMed Central

    Schwarz, G; Callewaert, G; Droogmans, G; Nilius, B

    1992-01-01

    1. Changes of the free cytosolic Ca2+ concentration induced by shear stress were measured in Fura-2 acetoxymethyl ester-loaded endothelial cells from human umbilical cord veins. 2. We were able to induce Ca2+ transients in almost every cell by blowing a stream of physiological solution onto a single endothelial cell thereby inducing shear stress between 0 and 50 dyn cm-2. The Ca2+ response could be graded by varying the shear stress, and reached a half-maximal value at a shear stress of 30 dyn cm-2. 3. The shear stress responses critically depended on the extracellular Ca2+ concentration and were absent in a Ca(2+)-free solution. Repetitive application of short pulses of shear stress induced cumulative effects because of the slow decay of the shear stress Ca2+ responses (time constants 82.3 +/- 17.8 s from twenty-five cells). Application of a depolarizing high potassium solution to reduce the driving force for Ca2+ entry decreased the Ca2+ transients in some of the cells. 4. Application of shear stress in the presence of other divalent cations, such as nickel, cobalt or barium, always produced substantial changes in the ratio of the 390/360 nm fluorescence signal, indicating influx of these cations and subsequent quenching of the Fura-2 fluorescence. 5. Shear stress responses in the presence of 10 mM Ca2+ were completely blocked by application of 1 mM La3+. 6. Incubation of the cells with the phorbol ester 12-O-tetradecanoyl phorbol-13-acetate (TPA) did not alter the shear stress response, but completely blocked histamine-induced Ca2+ transients. 7. Small submaximal shear stress potentiated the Ca2+ transients induced by histamine. 8. We conclude that shear stress-dependent Ca2+ signals are induced by an influx of calcium that is not modulated via protein kinase C and not activated by membrane depolarization. The influx pathway is also permeable to divalent cations such as Ni2+, Co2+ and Ba2+, but is blocked by La3+. PMID:1338792

  13. Growth differentiation factor-15 promotes glutamate release in medial prefrontal cortex of mice through upregulation of T-type calcium channels.

    PubMed

    Liu, Dong-Dong; Lu, Jun-Mei; Zhao, Qian-Ru; Hu, Changlong; Mei, Yan-Ai

    2016-06-29

    Growth differentiation factor-15 (GDF-15) has been implicated in ischemic brain injury and synapse development, but its involvement in modulating neuronal excitability and synaptic transmission remain poorly understood. In this study, we investigated the effects of GDF-15 on non-evoked miniature excitatory post-synaptic currents (mEPSCs) and neurotransmitter release in the medial prefrontal cortex (mPFC) in mice. Incubation of mPFC slices with GDF-15 for 60 min significantly increased the frequency of mEPSCs without effect on their amplitude. GDF-15 also significantly elevated presynaptic glutamate release, as shown by HPLC. These effects were blocked by dual TGF-β type I receptor (TβRI) and TGF-β type II receptor (TβRII) antagonists, but not by a TβRI antagonist alone. Meanwhile, GDF-15 enhanced pERK level, and inhibition of MAPK/ERK activity attenuated the GDF-15-induced increases in mEPSC and glutamate release. Blocking T-type calcium channels reduced the GDF-15 induced up-regulation of synaptic transmission. Membrane-protein extraction and use of an intracellular protein-transport inhibitor showed that GDF-15 promoted CaV3.1 and CaV3.3 α-subunit expression by trafficking to the membrane. These results confirm previous findings in cerebellar granule neurons, in which GDF-15 induces its neurobiological effects via TβRII and activation of the ERK pathway, providing novel insights into the mechanism of GDF-15 function in cortical neurons.

  14. Induction of curvature in maize roots by calcium or by thigmostimulation: role of the postmitotic isodiametric growth zone

    NASA Technical Reports Server (NTRS)

    Ishikawa, H.; Evans, M. L.

    1992-01-01

    We examined the response of primary roots of maize (Zea mays L. cv Merit) to unilateral application of calcium with particular attention to the site of application, the dependence on growth rate, and possible contributions of thigmotropic stimulation during application. Unilateral application of agar to the root cap induced negative curvature whether or not the agar contained calcium. This apparent thigmotropic response was enhanced by including calcium in the agar. Curvature away from objects applied unilaterally to the extreme root tip occurred both in intact and detipped roots. When agar containing calcium chloride was applied to one side of the postmitotic isodiametric growth zone ( a region between the apical meristem and the elongation zone), the root curved toward the side of application. This response could not be induced by plain agar. We conclude that curvature away from calcium applied to the root tip results from a thigmotropic response to stimulation during application. In contrast, curvature toward the calcium applied to the postmitotic isodiametric growth zone results from direct calcium-induced inhibition of growth.

  15. An integrated platform for simultaneous multi-well field potential recording and Fura-2-based calcium transient ratiometry in human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes.

    PubMed

    Rast, Georg; Weber, Jürgen; Disch, Christoph; Schuck, Elmar; Ittrich, Carina; Guth, Brian D

    2015-01-01

    Human induced pluripotent stem cell-derived cardiomyocytes are available from various sources and they are being evaluated for safety testing. Several platforms are available offering different assay principles and read-out parameters: patch-clamp and field potential recording, imaging or photometry, impedance measurement, and recording of contractile force. Routine use will establish which assay principle and which parameters best serve the intended purpose. We introduce a combination of field potential recording and calcium ratiometry from spontaneously beating cardiomyocytes as a novel assay providing a complementary read-out parameter set. Field potential recording is performed using a commercial multi-well multi-electrode array platform. Calcium ratiometry is performed using a fiber optic illumination and silicon avalanche photodetectors. Data condensation and statistical analysis are designed to enable statistical inference of differences and equivalence with regard to a solvent control. Simultaneous recording of field potentials and calcium transients from spontaneously beating monolayers was done in a nine-well format. Calcium channel blockers (e.g. nifedipine) and a blocker of calcium store release (ryanodine) can be recognized and discriminated based on the calcium transient signal. An agonist of L-type calcium channels, FPL 64176, increased and prolonged the calcium transient, whereas BAY K 8644, another L-type calcium channel agonist, had no effect. Both FPL 64176 and various calcium channel antagonists have chronotropic effects, which can be discriminated from typical "chronotropic" compounds, like (±)isoprenaline (positive) and arecaidine propargyl ester (negative), based on their effects on the calcium transient. Despite technical limitations in temporal resolution and exact matching of composite calcium transient with the field potential of a subset of cells, the combined recording platform enables a refined interpretation of the field potential

  16. Hypoxia-inducible factor 1α is a critical downstream mediator for hypoxia-induced mitogenic factor (FIZZ1/RELMα)-induced pulmonary hypertension

    PubMed Central

    Johns, Roger A.; Takimoto, Eiki; Meuchel, Lucas W.; Elsaigh, Esra; Zhang, Ailan; Heller, Nicola M.; Semenza, Gregg L.; Yamaji-Kegan, Kazuyo

    2017-01-01

    Objective Pulmonary hypertension (PH) is characterized by progressive elevation of pulmonary vascular resistance, right ventricular failure, and ultimately death. We have shown that in rodents, hypoxia-induced mitogenic factor (HIMF; also known as FIZZ1 or RELMα) causes PH by initiating lung vascular inflammation. We hypothesized that hypoxia-inducible factor-1 (HIF-1) is a critical downstream signal mediator of HIMF during PH development. Approach and Results In this study, we compared the degree of HIMF-induced pulmonary vascular remodeling and PH development in wild-type (HIF-1α+/+) and HIF-1α heterozygous null (HIF-1α+/−) mice. HIMF-induced PH was significantly diminished in HIF-1α+/− mice and was accompanied by a dysregulated VEGF-A–VEGF receptor 2 pathway. HIF-1α was critical for bone marrow-derived cell migration and vascular tube formation in response to HIMF. Furthermore, HIMF and its human homolog, resistin-like molecule-β (RELMβ), significantly increased IL-6 in macrophages and lung resident cells through a mechanism dependent on HIF-1α and, at least to some extent, on nuclear factor κB. Conclusions Our results suggest that HIF-1α is a critical downstream transcription factor for HIMF-induced pulmonary vascular remodeling and PH development. Importantly, both HIMF and human RELMβ significantly increased IL-6 in lung resident cells and increased perivascular accumulation of IL-6–expressing macrophages in the lungs of mice. These data suggest that HIMF can induce HIF-1, VEGF-A, and interleukin-6, which are critical mediators of both hypoxic inflammation and PH pathophysiology. PMID:26586659

  17. Involvement of mitochondrial proteins in calcium signaling and cell death induced by staurosporine in Neurospora crassa.

    PubMed

    Gonçalves, A Pedro; Cordeiro, J Miguel; Monteiro, João; Lucchi, Chiara; Correia-de-Sá, Paulo; Videira, Arnaldo

    2015-10-01

    Staurosporine-induced cell death in Neurospora crassa includes a well defined sequence of alterations in cytosolic calcium levels, comprising extracellular Ca(2+) influx and mobilization of Ca(2+) from internal stores. Here, we show that cells undergoing respiratory stress due to the lack of certain components of the mitochondrial complex I (like the 51kDa and 14kDa subunits) or the Ca(2+)-binding alternative NADPH dehydrogenase NDE-1 are hypersensitive to staurosporine and incapable of setting up a proper intracellular Ca(2+) response. Cells expressing mutant forms of NUO51 that mimic human metabolic diseases also presented Ca(2+) signaling deficiencies. Accumulation of reactive oxygen species is increased in cells lacking NDE-1 and seems to be required for Ca(2+) oscillations in response to staurosporine. Measurement of the mitochondrial levels of Ca(2+) further supported the involvement of these organelles in staurosporine-induced Ca(2+) signaling. In summary, our data indicate that staurosporine-induced fungal cell death involves a sophisticated response linking Ca(2+) dynamics and bioenergetics. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Extracellular calcium regulates protein tyrosine phosphorylation through calcium-sensing receptor (CaSR) in stallion sperm.

    PubMed

    Macías-García, Beatriz; Rocha, Antonio; González-Fernández, Lauro

    2016-03-01

    Protein tyrosine phosphorylation (PY), a hallmark of sperm capacitation, is inhibited by extracellular calcium in stallion sperm. The objective of this study was to determine the presence and influence of the calcium-sensing receptor (CaSR) in this phenomenon. First, the presence of the CaSR was demonstrated in stallion sperm. We then tested its function in these gametes using its inhibitor NPS2143 or its agonist AC34356. Sperm were capacitated for 4 hr in modified Whitten's medium with 25 mM bicarbonate plus NPS2143 and 2.4 mM calcium or AC34356 alone, followed by analysis of PY. Inhibition of CaSR with NPS2143 prevented the calcium-dependent PY inhibition in a dose-dependent manner (5, 10, and 15 μM) whereas AC34356 (100 μM) inhibited PY similarly to calcium. Stallion sperm motility and viability significantly decreased in presence of 15 μM of NPS2143 whereas only sperm motility decreased with 100 μM of AC34356. CaSR function was also studied in the complete absence of calcium by including 2 mM ethylene glycol tetraacetic acid (EGTA); under these conditions, AC34356 again inhibited PY, but this time induced a significant increase in sperm motility. Inhibition of calmodulin by W-7 did not recover the AC34356-mediated PY inhibition. When stallion sperm were incubated under capacitating conditions (calcium, bicarbonate, plus bovine serum albumin) at elevated pH (7.9 or 8.5) AC34356 did not block PY. These results thus elucidate the effect of extracellular conditions on the regulation of CaSR, and point to its modulatory role on stallion sperm PY, motility, and viability. Mol. Reprod. Dev. 83: 236-245, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  19. Timing of the calcium intake and effect of calcium deficiency on behaviour and egg laying in captive great tits, Parus major.

    PubMed

    Graveland, J; Berends, A E

    1997-01-01

    The calcium demand of egg-laying birds is much higher than in other vertebrates during reproduction. We showed elsewhere that a low level of calcium availability can greatly affect the eggshell quality and reproduction of free-living passerines. However, there are few data on calcium demand and calcium intake in relation to egg laying and behaviour and egg-laying performance under conditions of calcium shortage in nondomesticated birds. We examined these aspects in an experiment with captive great tits, Parus major, on a diet deficient in calcium, with or without snail shells as an additional calcium source. More than 90% of the calcium intake for egg production took place during the egg-laying period. Females ingested about 1.7 times as much calcium as they deposited in eggshells. Removing the snail shells after the first egg resulted in eggshell defects and interruptions of laying after 1-3 d. Females without snail shells doubled their searching effort and started to burrow in the soil and to eat sand, small stones, and their own eggs. Most calcium was consumed in the evening, probably to supplement the calcium available from the medullary bone with an additional calcium source in the gut during eggshell formation. The results demonstrated that eggshell formation requires accurate timing of the calcium intake and that obtaining sufficient calcium is time-consuming, even in calcium-rich environments. These factors pertaining to calcium intake greatly affect the ability of birds to collect sufficient calcium for eggshell formation in calcium-poor areas.

  20. Gc-protein-derived macrophage activating factor counteracts the neuronal damage induced by oxaliplatin.

    PubMed

    Morucci, Gabriele; Branca, Jacopo J V; Gulisano, Massimo; Ruggiero, Marco; Paternostro, Ferdinando; Pacini, Alessandra; Di Cesare Mannelli, Lorenzo; Pacini, Stefania

    2015-02-01

    Oxaliplatin-based regimens are effective in metastasized advanced cancers. However, a major limitation to their widespread use is represented by neurotoxicity that leads to peripheral neuropathy. In this study we evaluated the roles of a proven immunotherapeutic agent [Gc-protein-derived macrophage activating factor (GcMAF)] in preventing or decreasing oxaliplatin-induced neuronal damage and in modulating microglia activation following oxaliplatin-induced damage. The effects of oxaliplatin and of a commercially available formula of GcMAF [oleic acid-GcMAF (OA-GcMAF)] were studied in human neurons (SH-SY5Y cells) and in human microglial cells (C13NJ). Cell density, morphology and viability, as well as production of cAMP and expression of vascular endothelial growth factor (VEGF), markers of neuron regeneration [neuromodulin or growth associated protein-43 (Gap-43)] and markers of microglia activation [ionized calcium binding adaptor molecule 1 (Iba1) and B7-2], were determined. OA-GcMAF reverted the damage inflicted by oxaliplatin on human neurons and preserved their viability. The neuroprotective effect was accompanied by increased intracellular cAMP production, as well as by increased expression of VEGF and neuromodulin. OA-GcMAF did not revert the effects of oxaliplatin on microglial cell viability. However, it increased microglial activation following oxaliplatin-induced damage, resulting in an increased expression of the markers Iba1 and B7-2 without any concomitant increase in cell number. When neurons and microglial cells were co-cultured, the presence of OA-GcMAF significantly counteracted the toxic effects of oxaliplatin. Our results demonstrate that OA-GcMAF, already used in the immunotherapy of advanced cancers, may significantly contribute to neutralizing the neurotoxicity induced by oxaliplatin, at the same time possibly concurring to an integrated anticancer effect. The association between these two powerful anticancer molecules would probably produce

  1. Involvement of the cervical sympathetic nervous system in the changes of calcium homeostasis during turpentine oil-induced stress in rats.

    PubMed

    Stern, J E; Ladizesky, M G; Keller Sarmiento, M I; Cardinali, D P

    1993-03-01

    Hypocalcemia is a common finding during stress. The objective of this study was to examine: (a) the changes in circulating calcium, parathyroid hormone (PTH) and calcitonin (CT) concentration in rats stressed by being given a subcutaneous injection of turpentine oil, and (b) the involvement of the sympathetic cervical pathway in stress-induced changes of calcium homeostasis. Four hours after receiving turpentine oil or vehicle, rats were subjected either to hypocalcemia, by being given EDTA intraperitoneally, or to hypercalcemia, by being injected CaCl2 intraperitoneally. Significant changes in serum calcium (10% decrease), serum PTH (28% increase) and CT levels (40% decrease) were observed in stressed rats. EDTA administration brought about a significantly greater hypocalcemia, and a higher PTH secretory response in turpentine oil-stressed rats. During stress, the increase of serum calcium after CaCl2 was significantly smaller, and the rise of CT was greater than in controls. In the case of CT the changes were still observed in rats subjected to superior cervical ganglionectomy (SCGx) 14 days earlier. In the case of PTH, the increase found in stressed rats, but not the augmented response after EDTA, was blunted by SCGx. The potentiation of hypocalcemia brought about by turpentine oil was no longer observed in SCGx rats. In vehicle-treated controls, SCGx delayed PTH response to hypocalcemia, but did not affect the increased response of CT to CaCl2 challenge. The results indicate that a number of changes in calcium homeostasis arise during turpentine oil stress in rats. SCGx was effective to modify the set point for PTH release, but played a minor role in affecting the augmentation of CT release during stress.

  2. Nanouric acid or nanocalcium phosphate as central nidus to induce calcium oxalate stone formation: a high-resolution transmission electron microscopy study on urinary nanocrystallites

    PubMed Central

    Gao, Jie; Xue, Jun-Fa; Xu, Meng; Gui, Bao-Song; Wang, Feng-Xin; Ouyang, Jian-Ming

    2014-01-01

    Purpose This study aimed to accurately analyze the relationship between calcium oxalate (CaOx) stone formation and the components of urinary nanocrystallites. Method High-resolution transmission electron microscopy (HRTEM), selected area electron diffraction, fast Fourier transformation of HRTEM, and energy dispersive X-ray spectroscopy were performed to analyze the components of these nanocrystallites. Results The main components of CaOx stones are calcium oxalate monohydrate and a small amount of dehydrate, while those of urinary nanocrystallites are calcium oxalate monohydrate, uric acid, and calcium phosphate. The mechanism of formation of CaOx stones was discussed based on the components of urinary nanocrystallites. Conclusion The formation of CaOx stones is closely related both to the properties of urinary nanocrystallites and to the urinary components. The combination of HRTEM, fast Fourier transformation, selected area electron diffraction, and energy dispersive X-ray spectroscopy could be accurately performed to analyze the components of single urinary nanocrystallites. This result provides evidence for nanouric acid and/or nanocalcium phosphate crystallites as the central nidus to induce CaOx stone formation. PMID:25258530

  3. Regulation of calcium signals in the nucleus by a nucleoplasmic reticulum

    PubMed Central

    Echevarría, Wihelma; Leite, M. Fatima; Guerra, Mateus T.; Zipfel, Warren R.; Nathanson, Michael H.

    2013-01-01

    Calcium is a second messenger in virtually all cells and tissues1. Calcium signals in the nucleus have effects on gene transcription and cell growth that are distinct from those of cytosolic calcium signals; however, it is unknown how nuclear calcium signals are regulated. Here we identify a reticular network of nuclear calcium stores that is continuous with the endoplasmic reticulum and the nuclear envelope. This network expresses inositol 1,4,5-trisphosphate (InsP3) receptors, and the nuclear component of InsP3-mediated calcium signals begins in its locality. Stimulation of these receptors with a little InsP3 results in small calcium signals that are initiated in this region of the nucleus. Localized release of calcium in the nucleus causes nuclear protein kinase C (PKC) to translocate to the region of the nuclear envelope, whereas release of calcium in the cytosol induces translocation of cytosolic PKC to the plasma membrane. Our findings show that the nucleus contains a nucleoplasmic reticulum with the capacity to regulate calcium signals in localized subnuclear regions. The presence of such machinery provides a potential mechanism by which calcium can simultaneously regulate many independent processes in the nucleus. PMID:12717445

  4. The Yin and Yang of Calcium Effects on Synaptic Vesicle Endocytosis

    PubMed Central

    Wu, Xin-Sheng

    2014-01-01

    A large number of studies suggest that calcium triggers and accelerates vesicle endocytosis at many synapses and non-neuronal secretory cells. However, many studies show that prolonging the duration of the stimulation train, which induces more calcium influx, slows down endocytosis; and several studies suggest that instead of triggering endocytosis, calcium actually inhibits endocytosis. Here we addressed this apparent conflict at a large nerve terminal, the calyx of Held in rat brainstem, in which recent studies suggest that transient calcium increase up to tens of micromolar concentration at the micro/nano domain triggers endocytosis. By dialyzing 0–1 μm calcium into the calyx via a whole-cell pipette, we found that slow endocytosis was inhibited by calcium dialysis in a concentration-dependent manner. Thus, prolonged, small, and global calcium increase inhibits endocytosis, whereas transient and large calcium increase at the micro/nano domain triggers endocytosis and facilitates endocytosis. This yin and yang effect of calcium may reconcile apparent conflicts regarding whether calcium accelerates or inhibits endocytosis. Whether endocytosis is fast or slow depends on the net outcome between the yin and yang effect of calcium. PMID:24523554

  5. The FGF-2-triggered protection of cardiac subsarcolemmal mitochondria from calcium overload is mitochondrial connexin 43-dependent.

    PubMed

    Srisakuldee, Wattamon; Makazan, Zhanna; Nickel, Barbara E; Zhang, Feixiong; Thliveris, James A; Pasumarthi, Kishore B S; Kardami, Elissavet

    2014-07-01

    Fibroblast growth factor 2 (FGF-2) protects the heart from ischaemia- and reperfusion-induced cell death by a mechanism linked to protein kinase C (PKC)ε-mediated connexin 43 (Cx43) phosphorylation. Cx43 localizes predominantly to gap junctions, but has also been detected at subsarcolemmal (SSM), but not interfibrillar (IFM), mitochondria, where it is considered important for cardioprotection. We have now examined the effect of FGF-2 administration to the heart on resistance to calcium-induced permeability transition (mPTP) of isolated SSM vs. IFM suspensions, in relation to mitochondrial PKCε/Cx43 levels, phosphorylation, and the presence of peptide Gap27, a Cx43 channel blocker. FGF-2 perfusion increased resistance to calcium-induced mPTP in SSM and IFM suspensions by 2.9- and 1.7-fold, respectively, compared with their counterparts from vehicle-perfused hearts, assessed spectrophotometrically as cyclosporine A-inhibitable swelling. The salutary effect of FGF-2 was lost in SSM, but not in IFM, in the presence of Gap27. FGF-2 perfusion increased relative levels of PKCε, phospho(p) PKCε, and Tom-20 translocase in SSM and IFM, and of Cx43 in SSM. Phospho-serine (pS) 262- and pS368-Cx43 showed a 30- and 8-fold increase, respectively, in SSM from FGF-2-treated, compared with untreated, hearts. Stimulation of control SSM with phorbol 12-myristate 13-acetate (PMA), a PKC activator, increased both calcium tolerance and mitochondrial Cx43 phosphorylation at S262 and S368. The PMA-induced phosphorylation of mitochondrial Cx43 was prevented by εV1-2, a PKCε-inhibiting peptide. SSM are more responsive than IFM to FGF-2-triggered protection from calcium-induced mPTP, by a mitochondrial Cx43 channel-mediated pathway, associated with mitochondrial Cx43 phosphorylation at PKCε target sites. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

  6. Calcium

    MedlinePlus

    ... You'll also find calcium in broccoli and dark green, leafy vegetables (especially collard and turnip greens, ... can enjoy good sources of calcium such as dark green, leafy vegetables, broccoli, chickpeas, and calcium-fortified ...

  7. Magnolol and honokiol regulate the calcium-activated potassium channels signaling pathway in Enterotoxigenic Escherichia coli-induced diarrhea mice.

    PubMed

    Deng, Yanli; Han, Xuefeng; Tang, Shaoxun; Xiao, Wenjun; Tan, Zhiliang; Zhou, Chuanshe; Wang, Min; Kang, Jinghe

    2015-05-15

    To explore the regulatory mechanisms of magnolol and honokiol on calcium-activated potassium channels signaling pathway in Enterotoxigenic Escherichia coli (ETEC)-induced diarrhea mice, the concentrations of serum chloride ion (Cl(-)), sodium ion (Na(+)), potassium ion (K(+)) and calcium ion (Ca(2+)) were measured. Additionally, the mRNA expressions of calmodulin 1 (CaM), calcium/calmodulin-dependent protein kinase II alpha subunit (CaMKIIα) and beta subunit (CaMKIIβ), ryanodine receptor 1, inositol 1,4,5-trisphosphate receptors (IP3 receptors), protein kinases C (PKC), potassium intermediate/small conductance calcium-activated channels (SK) and potassium large conductance calcium-activated channels(BK)were determined. A diarrhea mouse model was established using ETEC suspensions (3.29×10(9)CFU/ml) at a dosage of 0.02ml/g live body weight (BW). Magnolol or honokiol was intragastrically administered at dosages of 100 (M100 or H100), 300 (M300 or H300) and 500 (M500 or H500) mg/kg BW according to a 3×3 factorial arrangement. Magnolol and honokiol increased the Cl(-) and K(+) concentrations, further, upregulated the CaM, BKα1 and BKβ3 mRNA levels but downregulated the IP3 receptors 1, PKC, SK1, SK2, SK3, SK4 and BKβ4 mRNA expressions. Magnolol and honokiol did not alter the CaMKIIα, CaMKIIβ, ryanodine receptor 1, IP3 receptor 2, IP3 receptor 3, BKβ1 and BKβ2 mRNA expressions. These results clarify that magnolol and honokiol, acting through Ca(2+) channel blockade, inhibit the activation of IP3 receptor 1 to regulate the IP3-Ca(2+) store release, activate CaM to inhibit SK channels, and effectively suppress PKC kinases to promote BKα1 and BKβ3 channels opening and BKβ4 channel closing, which modulates the intestinal ion secretion. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Fibromodulin modulates myoblast differentiation by controlling calcium channel.

    PubMed

    Lee, Eun Ju; Nam, Joo Hyun; Choi, Inho

    2018-06-16

    Fibromodulin (FMOD) is a proteoglycan present in extracellular matrix (ECM). Based on our previous findings that FMOD controls myoblast differentiation by regulating the gene expressions of collagen type I alpha 1 (COL1α1) and integral membrane protein 2 A (Itm2a), we undertook this study to investigate relationships between FMOD and calcium channels and to understand further the mechanism by which they control myoblast differentiation. Gene expression studies and luciferase reporter assays showed FMOD affected calcium channel gene expressions by regulating calcium channel gene promoter, and patch-clamp experiments showed both L- and T-type calcium channel currents were almost undetectable in FMOD knocked down cells. In addition, gene knock-down studies demonstrated the COL1α1 and Itm2a genes both regulate the expressions of calcium channel genes. Studies using a cardiotoxin-induced mouse muscle injury model demonstrated calcium channels play important roles in the regeneration of muscle tissue, possibly by promoting the differentiation of muscle stem cells (MSCs). Summarizing, the study demonstrates ECM components secreted by myoblasts during differentiation provide an essential environment for muscle differentiation and regeneration. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. Implication of the ryanodine receptor in TRPV4-induced calcium response in pulmonary arterial smooth muscle cells from normoxic and chronically hypoxic rats.

    PubMed

    Dahan, Diana; Ducret, Thomas; Quignard, Jean-François; Marthan, Roger; Savineau, Jean-Pierre; Estève, Eric

    2012-11-01

    There is a growing body of evidence indicating that transient receptor potential (TRP) channels are implicated in calcium signaling and various cellular functions in the pulmonary vasculature. The aim of this study was to investigate the expression, functional role, and coupling to reticulum calcium channels of the type 4 vanilloid TRP subfamily (TRPV4) in the pulmonary artery from both normoxic (Nx) and chronically hypoxic (CH) rats. Activation of TRPV4 with the specific agonist 4α-phorbol-12,13-didecanoate (4α-PDD, 5 μM) increased the intracellular calcium concentration ([Ca(2+)](i)). This effect was significantly reduced by a high concentration of ryanodine (100 μM) or chronic caffeine (5 mM) that blocked ryanodine receptor (RyR) but was insensitive to xestospongin C (10 μM), an inositol trisphosphate receptor antagonist. Inhibition of RyR1 and RyR3 only with 10 μM of dantrolene did not attenuate the 4α-PDD-induced [Ca(2+)](i) increase. Western blotting experiments revealed the expression of TRPV4 and RyR2 with an increase in both receptors in pulmonary arteries from CH rats vs. Nx rats. Accordingly, the 4α-PDD-activated current, measured with patch-clamp technique, was increased in pulmonary artery smooth muscle cells (PASMC) from CH rats vs. Nx rats. 4α-PDD increased isometric tension in artery rings, and this response was also potentiated under chronic hypoxia conditions. 4α-PDD-induced calcium response, current, and contraction were all inhibited by the selective TRPV4 blocker HC-067047. Collectively, our findings provide evidence of the interplay between TRPV4 and RyR2 in the Ca(2+) release mechanism and contraction in PASMC. This study provides new insights onto the complex calcium signaling in PASMC and point out the importance of the TRPV4-RyR2 signaling pathway under hypoxic conditions that may lead to pulmonary hypertension.

  10. Calcium/calmodulin-mediated signal network in plants

    NASA Technical Reports Server (NTRS)

    Yang, Tianbao; Poovaiah, B. W.

    2003-01-01

    Various extracellular stimuli elicit specific calcium signatures that can be recognized by different calcium sensors. Calmodulin, the predominant calcium receptor, is one of the best-characterized calcium sensors in eukaryotes. In recent years, completion of the Arabidopsis genome project and advances in functional genomics have helped to identify and characterize numerous calmodulin-binding proteins in plants. There are some similarities in Ca(2+)/calmodulin-mediated signaling in plants and animals. However, plants possess multiple calmodulin genes and many calmodulin target proteins, including unique protein kinases and transcription factors. Some of these proteins are likely to act as "hubs" during calcium signal transduction. Hence, a better understanding of the function of these calmodulin target proteins should help in deciphering the Ca(2+)/calmodulin-mediated signal network and its role in plant growth, development and response to environmental stimuli.

  11. Plasma membrane calcium ATPase 4b inhibits nitric oxide generation through calcium-induced dynamic interaction with neuronal nitric oxide synthase.

    PubMed

    Duan, Wenjuan; Zhou, Juefei; Li, Wei; Zhou, Teng; Chen, Qianqian; Yang, Fuyu; Wei, Taotao

    2013-04-01

    The activation and deactivation of Ca(2+)- and calmodulindependent neuronal nitric oxide synthase (nNOS) in the central nervous system must be tightly controlled to prevent excessive nitric oxide (NO) generation. Considering plasma membrane calcium ATPase (PMCA) is a key deactivator of nNOS, the present investigation aims to determine the key events involved in nNOS deactivation of by PMCA in living cells to maintain its cellular context. Using time-resolved Förster resonance energy transfer (FRET), we determined the occurrence of Ca(2+)-induced protein-protein interactions between plasma membrane calcium ATPase 4b (PMCA4b) and nNOS in living cells. PMCA activation significantly decreased the intracellular Ca(2+) concentrations ([Ca(2+)]i), which deactivates nNOS and slowdowns NO synthesis. Under the basal [Ca(2+)]i caused by PMCA activation, no protein-protein interactions were observed between PMCA4b and nNOS. Furthermore, both the PDZ domain of nNOS and the PDZ-binding motif of PMCA4b were essential for the protein-protein interaction. The involvement of lipid raft microdomains on the activity of PMCA4b and nNOS was also investigated. Unlike other PMCA isoforms, PMCA4 was relatively more concentrated in the raft fractions. Disruption of lipid rafts altered the intracellular localization of PMCA4b and affected the interaction between PMCA4b and nNOS, which suggest that the unique lipid raft distribution of PMCA4 may be responsible for its regulation of nNOS activity. In summary, lipid rafts may act as platforms for the PMCA4b regulation of nNOS activity and the transient tethering of nNOS to PMCA4b is responsible for rapid nNOS deactivation.

  12. Medical therapy, calcium oxalate urolithiasis

    NASA Technical Reports Server (NTRS)

    Ruml, L. A.; Pearle, M. S.; Pak, C. Y.

    1997-01-01

    The development of diagnostic protocols that identify specific risk factors for calcium oxalate nephrolithiasis has led to the formulation of directed medical regimens that are aimed at correcting the underlying metabolic disturbances. Initiation of these treatment programs has reduced markedly the rate of stone formation in the majority of patients who form stones. This article discusses the rationale that underlies the choice of medical therapy for the various pathophysiologic causes of calcium oxalate nephrolithiasis and the appropriate use of available medications.

  13. Protection of Dentate Hilar Cells from Prolonged Stimulation by Intracellular Calcium Chelation

    NASA Astrophysics Data System (ADS)

    Scharfman, Helen E.; Schwartzkroin, Philip A.

    1989-10-01

    Prolonged afferent stimulation of the rat dentate gyrus in vivo leads to degeneration only of those cells that lack immunoreactivity for the calcium binding proteins parvalbumin and calbindin. In order to test the hypothesis that calcium binding proteins protect against the effects of prolonged stimulation, intracellular recordings were made in hippocampal slices from cells that lack immunoreactivity for calcium binding proteins. Calcium binding protein--negative cells showed electrophysiological signs of deterioration during prolonged stimulation; cells containing calcium binding protein did not. When neurons without calcium binding proteins were impaled with microelectrodes containing the calcium chelator BAPTA, and BAPTA was allowed to diffuse into the cells, these cells showed no deterioration. These results indicate that, in a complex tissue of the central nervous system, an activity-induced increase in intracellular calcium can trigger processes leading to cell deterioration, and that increasing the calcium binding capacity of a cell decreases its vulnerability to damage.

  14. Sclerostin alters serum vitamin D metabolite and fibroblast growth factor 23 concentrations and the urinary excretion of calcium

    PubMed Central

    Ryan, Zachary C.; Ketha, Hemamalini; McNulty, Melissa S.; McGee-Lawrence, Meghan; Craig, Theodore A.; Grande, Joseph P.; Westendorf, Jennifer J.; Singh, Ravinder J.; Kumar, Rajiv

    2013-01-01

    Inactivating mutations of the SOST (sclerostin) gene are associated with overgrowth and sclerosis of the skeleton. To determine mechanisms by which increased amounts of calcium and phosphorus are accreted to enable enhanced bone mineralization in the absence of sclerostin, we measured concentrations of calciotropic and phosphaturic hormones, and urine and serum calcium and inorganic phosphorus in mice in which the sclerostin (sost) gene was replaced by the β-D-galactosidase (lacZ) gene in the germ line. Knockout (KO) (sost−/−) mice had increased bone mineral density and content, increased cortical and trabecular bone thickness, and greater net bone formation as a result of increased osteoblast and decreased osteoclast surfaces compared with wild-type (WT) mice. β-Galactosidase activity was detected in osteocytes of sost KO mice but was undetectable in WT mice. Eight-week-old, male sost KO mice had increased serum 1α,25-dihydroxyvitamin D, decreased 24,25-dihydroxyvitamin D, decreased intact fibroblast growth factor 23, and elevated inorganic phosphorus concentrations compared with age-matched WT mice. 25-Hydroxyvitamin D 1α-hydroxylase cytochrome P450 (cyp27B1) mRNA was increased in kidneys of sost KO mice compared with WT mice. Treatment of cultured proximal tubule cells with mouse recombinant sclerostin decreased cyp27B1 mRNA transcripts. Urinary calcium and renal fractional excretion of calcium were decreased in sost KO mice compared with WT mice. Sost KO and WT mice had similar serum calcium and parathyroid hormone concentrations. The data show that sclerostin not only alters bone mineralization, but also influences mineral metabolism by altering concentrations of hormones that regulate mineral accretion. PMID:23530237

  15. Sclerostin alters serum vitamin D metabolite and fibroblast growth factor 23 concentrations and the urinary excretion of calcium.

    PubMed

    Ryan, Zachary C; Ketha, Hemamalini; McNulty, Melissa S; McGee-Lawrence, Meghan; Craig, Theodore A; Grande, Joseph P; Westendorf, Jennifer J; Singh, Ravinder J; Kumar, Rajiv

    2013-04-09

    Inactivating mutations of the SOST (sclerostin) gene are associated with overgrowth and sclerosis of the skeleton. To determine mechanisms by which increased amounts of calcium and phosphorus are accreted to enable enhanced bone mineralization in the absence of sclerostin, we measured concentrations of calciotropic and phosphaturic hormones, and urine and serum calcium and inorganic phosphorus in mice in which the sclerostin (sost) gene was replaced by the β-D-galactosidase (lacZ) gene in the germ line. Knockout (KO) (sost(-/-)) mice had increased bone mineral density and content, increased cortical and trabecular bone thickness, and greater net bone formation as a result of increased osteoblast and decreased osteoclast surfaces compared with wild-type (WT) mice. β-Galactosidase activity was detected in osteocytes of sost KO mice but was undetectable in WT mice. Eight-week-old, male sost KO mice had increased serum 1α,25-dihydroxyvitamin D, decreased 24,25-dihydroxyvitamin D, decreased intact fibroblast growth factor 23, and elevated inorganic phosphorus concentrations compared with age-matched WT mice. 25-Hydroxyvitamin D 1α-hydroxylase cytochrome P450 (cyp27B1) mRNA was increased in kidneys of sost KO mice compared with WT mice. Treatment of cultured proximal tubule cells with mouse recombinant sclerostin decreased cyp27B1 mRNA transcripts. Urinary calcium and renal fractional excretion of calcium were decreased in sost KO mice compared with WT mice. Sost KO and WT mice had similar serum calcium and parathyroid hormone concentrations. The data show that sclerostin not only alters bone mineralization, but also influences mineral metabolism by altering concentrations of hormones that regulate mineral accretion.

  16. Oxidized Low-density Lipoprotein (ox-LDL) Cholesterol Induces the Expression of miRNA-223 and L-type Calcium Channel Protein in Atrial Fibrillation

    PubMed Central

    He, Fengping; Xu, Xin; Yuan, Shuguo; Tan, Liangqiu; Gao, Lingjun; Ma, Shaochun; Zhang, Shebin; Ma, Zhanzhong; Jiang, Wei; Liu, Fenglian; Chen, Baofeng; Zhang, Beibei; Pang, Jungang; Huang, Xiuyan; Weng, Jiaqiang

    2016-01-01

    Atrial fibrillation (AF) is the most common sustained arrhythmia causing high morbidity and mortality. While changing of the cellular calcium homeostasis plays a critical role in AF, the L-type calcium channel α1c protein has suggested as an important regulator of reentrant spiral dynamics and is a major component of AF-related electrical remodeling. Our computational modeling predicted that miRNA-223 may regulate the CACNA1C gene which encodes the cardiac L-type calcium channel α1c subunit. We found that oxidized low-density lipoprotein (ox-LDL) cholesterol significantly up-regulates both the expression of miRNA-223 and L-type calcium channel protein. In contrast, knockdown of miRNA-223 reduced L-type calcium channel protein expression, while genetic knockdown of endogenous miRNA-223 dampened AF vulnerability. Transfection of miRNA-223 by adenovirus-mediated expression enhanced L-type calcium currents and promoted AF in mice while co-injection of a CACNA1C-specific miR-mimic counteracted the effect. Taken together, ox-LDL, as a known factor in AF-associated remodeling, positively regulates miRNA-223 transcription and L-type calcium channel protein expression. Our results implicate a new molecular mechanism for AF in which miRNA-223 can be used as an biomarker of AF rheumatic heart disease. PMID:27488468

  17. Oxidized Low-density Lipoprotein (ox-LDL) Cholesterol Induces the Expression of miRNA-223 and L-type Calcium Channel Protein in Atrial Fibrillation

    NASA Astrophysics Data System (ADS)

    He, Fengping; Xu, Xin; Yuan, Shuguo; Tan, Liangqiu; Gao, Lingjun; Ma, Shaochun; Zhang, Shebin; Ma, Zhanzhong; Jiang, Wei; Liu, Fenglian; Chen, Baofeng; Zhang, Beibei; Pang, Jungang; Huang, Xiuyan; Weng, Jiaqiang

    2016-08-01

    Atrial fibrillation (AF) is the most common sustained arrhythmia causing high morbidity and mortality. While changing of the cellular calcium homeostasis plays a critical role in AF, the L-type calcium channel α1c protein has suggested as an important regulator of reentrant spiral dynamics and is a major component of AF-related electrical remodeling. Our computational modeling predicted that miRNA-223 may regulate the CACNA1C gene which encodes the cardiac L-type calcium channel α1c subunit. We found that oxidized low-density lipoprotein (ox-LDL) cholesterol significantly up-regulates both the expression of miRNA-223 and L-type calcium channel protein. In contrast, knockdown of miRNA-223 reduced L-type calcium channel protein expression, while genetic knockdown of endogenous miRNA-223 dampened AF vulnerability. Transfection of miRNA-223 by adenovirus-mediated expression enhanced L-type calcium currents and promoted AF in mice while co-injection of a CACNA1C-specific miR-mimic counteracted the effect. Taken together, ox-LDL, as a known factor in AF-associated remodeling, positively regulates miRNA-223 transcription and L-type calcium channel protein expression. Our results implicate a new molecular mechanism for AF in which miRNA-223 can be used as an biomarker of AF rheumatic heart disease.

  18. Curcumin induces crosstalk between autophagy and apoptosis mediated by calcium release from the endoplasmic reticulum, lysosomal destabilization and mitochondrial events

    PubMed Central

    Moustapha, A; Pérétout, PA; Rainey, NE; Sureau, F; Geze, M; Petit, J-M; Dewailly, E; Slomianny, C; Petit, PX

    2015-01-01

    Curcumin, a major active component of turmeric (Curcuma longa, L.), has anticancer effects. In vitro studies suggest that curcumin inhibits cancer cell growth by activating apoptosis, but the mechanism underlying these effects is still unclear. Here, we investigated the mechanisms leading to apoptosis in curcumin-treated cells. Curcumin induced endoplasmic reticulum stress causing calcium release, with a destabilization of the mitochondrial compartment resulting in apoptosis. These events were also associated with lysosomal membrane permeabilization and of caspase-8 activation, mediated by cathepsins and calpains, leading to Bid cleavage. Truncated tBid disrupts mitochondrial homeostasis and enhance apoptosis. We followed the induction of autophagy, marked by the formation of autophagosomes, by staining with acridine orange in cells exposed curcumin. At this concentration, only the early events of apoptosis (initial mitochondrial destabilization with any other manifestations) were detectable. Western blotting demonstrated the conversion of LC3-I to LC3-II (light chain 3), a marker of active autophagosome formation. We also found that the production of reactive oxygen species and formation of autophagosomes following curcumin treatment was almost completely blocked by N-acetylcystein, the mitochondrial specific antioxidants MitoQ10 and SKQ1, the calcium chelators, EGTA-AM or BAPTA-AM, and the mitochondrial calcium uniporter inhibitor, ruthenium red. Curcumin-induced autophagy failed to rescue all cells and most cells underwent type II cell death following the initial autophagic processes. All together, these data imply a fail-secure mechanism regulated by autophagy in the action of curcumin, suggesting a therapeutic potential for curcumin. Offering a novel and effective strategy for the treatment of malignant cells. PMID:27551451

  19. Calcium-Mediated Apoptosis and Apoptotic Sensitization in Prostate Cancer

    DTIC Science & Technology

    2003-06-01

    tyrosine phosphatase, PTP1B . To study their direct involvement in apoptosis and signaling, PC cells were transfected with dominant negative caspase 7...and inducible constructs of activated PTP1B B. Dominant negative caspase 7 suppressed activation of endogenous caspase 7 by calcium ionophore...supporting a role for its recruitment into the calcium initiated apoptotic process. Activated PTP1B expression (but not a phosphatase-dead mutant

  20. [Calcium kidney stones. Diagnostic and preventive prospects].

    PubMed

    Arcidiacono, T; Terranegra, A; Biasion, R; Soldati, L; Vezzoli, G

    2007-01-01

    Kidney stone disease is one of the main causes of hospitalization in Italy. Its prevalence increased in the last century and is probably still increasing. The pathogenesis of the disease is not known, although two main theories have been elaborated. The first hypothesizes that hydroxyapatite deposition in the interstitium of the renal papillae (Randall's plaque) precedes urinary calcium oxalate precipitation on the ulcered surface of the papilla to form a stone. The second presumes the tubular lumen of Bellini's duct to be the site where calcium-oxalate salts precipitate to form the nucleus for stone formation within the urinary tract. These pathogenetic processes may be favored by different dietary and genetic factors. The genes involved are not known, although many studies have been performed. Polymorphisms of genes coding for the vitamin D receptor, calcium-sensing receptor, interleukin-1 receptor antagonist, and urokinase were found to be associated with kidney stones, but these results have not been replicated. Different nutrients are suspected to predispose patients to calcium kidney stone disease. A high intake of animal proteins, sodium, vitamin C and oxalate has been implicated in stone formation, whereas calcium, alkalis and phytate may have a protective effect. The prevention of calcium stone formation is based on the recognition of risk factors like those already mentioned here. Furthermore, a family history of kidney stones may be useful in identifying subjects predisposed to become calcium stone formers. However, the expectations of the scientific community are turned to the advances in genetics and to the findings of genetic studies, which may provide diagnostic tools and criteria to define the risk profile of the single individual.

  1. Micropore-induced Capillarity Enhances Bone Distribution in vivo in Biphasic Calcium Phosphate Scaffolds

    PubMed Central

    Rustom, Laurence E.; Boudou, Thomas; Lou, Siyu; Pignot-Paintrand, Isabelle; Nemke, Brett W.; Lu, Yan; Markel, Mark D.; Picart, Catherine; Wagoner Johnson, Amy J.

    2016-01-01

    The increasing demand for bone repair solutions calls for the development of efficacious bone scaffolds. Biphasic calcium phosphate (BCP) scaffolds with both macropores and micropores (MP) have improved healing compared to those with macropores and no micropores (NMP), but the role of micropores is unclear. Here, we evaluate capillarity induced by micropores as a mechanism that can affect bone growth in vivo. Three groups of cylindrical scaffolds were implanted in pig mandibles for three weeks: MP were implanted either dry (MP-Dry), or after submersion in phosphate buffered saline, which fills pores with fluid and therefore suppresses micropore-induced capillarity (MP-Wet); NMP were implanted dry. The amount and distribution of bone in the scaffolds were quantified using micro-computed tomography. MP-Dry had a more homogeneous bone distribution than MP-Wet, although the average bone volume fraction, BVF¯, was not significantly different for these two groups (0.45±0.03 and 0.37±0.03, respectively). There was no significant difference in the radial bone distribution of NMP and MP-Wet, but the BVF¯ of NMP was significantly lower among the three groups (0.25±0.02). These results suggest that micropore-induced capillarity enhances bone regeneration by improving the homogeneity of bone distribution in BCP scaffolds. The explicit design and use of capillarity in bone scaffolds may lead to more effective treatments of large and complex bone defects. PMID:27544807

  2. Influence of whole-body irradiation on calcium and phosphate homeostasis in the rat

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

    Pento, J.T.; Kenny, A.D.

    1975-09-01

    Previous irradiation studies have revealed marked alterations in calcium metabolism. Moreover, the maintenance of calcium homeostasis with parathyroid hormone or calcium salts has been reported to reduce radiation lethality. Therefore, the present study was designed to evaluate the influence of irradiation on calcium homeostasis in the rat. Nine hundred rad of whole-body irradiation produced a significant depression of both plasma calcium and phosphate at 4 days postirradiation. This effect of irradiation was observed to be dose-dependent over a range of 600 to 1200 rad, and possibly related to irradiation-induced anorexia. The physiological significance of these observations is discussed. (auth)

  3. Exogenous calcium induces tolerance to atrazine stress in Pennisetum seedlings and promotes photosynthetic activity, antioxidant enzymes and psbA gene transcripts.

    PubMed

    Erinle, Kehinde Olajide; Jiang, Zhao; Ma, Bingbing; Li, Jinmei; Chen, Yukun; Ur-Rehman, Khalil; Shahla, Andleeb; Zhang, Ying

    2016-10-01

    Calcium (Ca) has been reported to lessen oxidative damages in plants by upregulating the activities of antioxidant enzymes. However, atrazine mediated reactive oxygen species (ROS) reduction by Ca is limited. This study therefore investigated the effect of exogenously applied Ca on ROS, antioxidants activity and gene transcripts, the D1 protein (psbA gene), and chlorophyll contents in Pennisetum seedlings pre-treated with atrazine. Atrazine toxicity increased ROS production and enzyme activities (ascorbate peroxidase APX, peroxidase POD, Superoxide dismutase SOD, glutathione-S-transferase GST); but decreased antioxidants (APX, POD, and Cu/Zn SOD) and psbA gene transcripts. Atrazine also decreased the chlorophyll contents, but increased chlorophyll (a/b) ratio. Contrarily, Ca application to atrazine pre-treated seedlings lowered the harmful effects of atrazine by reducing ROS levels, but enhancing the accumulation of total chlorophyll contents. Ca-protected seedlings in the presence of atrazine manifested reduced APX and POD activity, whereas SOD and GST activity was further increased with Ca application. Antioxidant gene transcripts that were down-regulated by atrazine toxicity were up-regulated with the application of Ca. Calcium application also resulted in up-regulation of the D1 protein. In conclusion, ability of calcium to reverse atrazine-induced oxidative damage and calcium regulatory role on GST in Pennisetum was presented. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Calcium intake trends and health consequences from childhood through adulthood.

    PubMed

    Nicklas, Theresa A

    2003-10-01

    Issues involving low calcium intake and dairy product consumption are currently the focus of much debate and discussion at both the scientific and lay community levels. In this review, we examine the following major areas of interest: (1). the role of calcium intake and dairy product consumption in chronic diseases, (2). nutritional qualities of milk and other dairy products, (3). trends in calcium intake and dairy product consumption, (4). current status of calcium intakes and dairy product consumption in children, (5). tracking of calcium intake and diary product consumption, (6). the impact of school meal participation on calcium intake and dairy product consumption, (7). concerns related to calcium-fortified foods and beverages and (8). factors influencing children's milk consumption. To date, the findings indicate that calcium intake and dairy product consumption have beneficial roles in a variety of chronic diseases; dairy products provide an abundant source of vitamins and minerals; calcium intakes of children have increased over time, yet intakes are not meeting the current adequate intake (AI) calcium recommendations; dairy consumption has decreased, and soft drink consumption and, possibly, consumption of calcium-fortified products have increased; consumption of dairy products have a positive nutritional impact on diets of children, particularly from school meals, and there are many factors which influence children's milk consumption, all of which need to be considered in our efforts to promote adequate calcium intakes by children. Based on this review, areas that need immediate attention and future research imperatives are summarized in an effort to further our understanding on what we already know and what we need to know to promote healthier eating habits early in life.

  5. Arsenic-induced alteration in intracellular calcium homeostasis induces head kidney macrophage apoptosis involving the activation of calpain-2 and ERK in Clarias batrachus

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

    Banerjee, Chaitali; Goswami, Ramansu; Centre for Environmental Studies, Visva-Bharati University, Santiniketan 731 235

    2011-10-01

    We had earlier shown that exposure to arsenic (0.50 {mu}M) caused caspase-3 mediated head kidney macrophage (HKM) apoptosis involving the p38-JNK pathway in Clarias batrachus. Here we examined the roles of calcium (Ca{sup 2+}) and extra-cellular signal-regulated protein kinase (ERK), the other member of MAPK-pathway on arsenic-induced HKM apoptosis. Arsenic-induced HKM apoptosis involved increased expression of ERK and calpain-2. Nifedipine, verapamil and EGTA pre-treatment inhibited the activation of calpain-2, ERK and reduced arsenic-induced HKM apoptosis as evidenced from reduced caspase-3 activity, Annexin V-FITC-propidium iodide and Hoechst 33342 staining. Pre-incubation with ERK inhibitor U 0126 inhibited the activation of calpain-2 andmore » interfered with arsenic-induced HKM apoptosis. Additionally, pre-incubation with calpain-2 inhibitor also interfered with the activation of ERK and inhibited arsenic-induced HKM apoptosis. The NADPH oxidase inhibitor apocynin and diphenyleneiodonium chloride also inhibited ERK activation indicating activation of ERK in arsenic-exposed HKM also depends on signals from NADPH oxidase pathway. Our study demonstrates the critical role of Ca{sup 2+} homeostasis on arsenic-induced HKM apoptosis. We suggest that arsenic-induced alteration in intracellular Ca{sup 2+} levels initiates pro-apoptotic ERK and calpain-2; the two pathways influence each other positively and induce caspase-3 mediated HKM apoptosis. Besides, our study also indicates the role of ROS in the activation of ERK pathway in arsenic-induced HKM apoptosis in C. batrachus. - Highlights: > Altered Ca{sup 2+} homeostasis leads to arsenic-induced HKM apoptosis. > Calpain-2 plays a critical role in the process. > ERK is pro-apoptotic in arsenic-induced HKM apoptosis. > Arsenic-induced HKM apoptosis involves cross talk between calpain-2 and ERK.« less

  6. Calcium oxalate monohydrate aggregation induced by aggregation of desialylated Tamm-Horsfall protein

    PubMed Central

    Viswanathan, Pragasam; Rimer, Jeffrey D.; Kolbach, Ann M.; Kleinman, Jack G.

    2011-01-01

    Tamm-Horsfall protein (THP) is thought to protect against calcium oxalate monohydrate (COM) stone formation by inhibiting COM aggregation. Several studies reported that stone formers produce THP with reduced levels of glycosylation, particularly sialic acid levels, which leads to reduced negative charge. In this study, normal THP was treated with neuraminidase to remove sialic acid residues, confirmed by an isoelectric point shift to higher pH. COM aggregation assays revealed that desialylated THP (ds-THP) promoted COM aggregation, while normal THP inhibited aggregation. The appearance of protein aggregates in solutions at ds-THP concentrations ≥1 µg/mL in 150 mM NaCl correlated with COM aggregation promotion, implying that ds-THP aggregation induced COM aggregation. The aggregation-promoting effect of the ds-THP was independent of pH above its isoelectric point, but was substantially reduced at low ionic strength, where protein aggregation was much reduced. COM aggregation promotion was maximized at a ds-THP to COM mass ratio of ~0.025, which can be explained by a model wherein partial COM surface coverage by ds-THP aggregates promotes crystal aggregation by bridging opposing COM surfaces, whereas higher surface coverage leads to repulsion between adsorbed ds-THP aggregates. Thus, desialylation of THP apparently abrogates a normal defensive action of THP by inducing protein aggregation, and subsequently COM aggregation, a condition that favors kidney stone formation. PMID:21229239

  7. Biomineralization of calcium carbonates and their engineered applications: a review

    PubMed Central

    Dhami, Navdeep K.; Reddy, M. Sudhakara; Mukherjee, Abhijit

    2013-01-01

    Microbially induced calcium carbonate precipitation (MICCP) is a naturally occurring biological process in which microbes produce inorganic materials as part of their basic metabolic activities. This technology has been widely explored and promising with potential in various technical applications. In the present review, the detailed mechanism of production of calcium carbonate biominerals by ureolytic bacteria has been discussed along with role of bacteria and the sectors where these biominerals are being used. The applications of bacterially produced carbonate biominerals for improving the durability of buildings, remediation of environment (water and soil), sequestration of atmospheric CO2 filler material in rubbers and plastics etc. are discussed. The study also sheds light on benefits of bacterial biominerals over traditional agents and also the issues that lie in the path of successful commercialization of the technology of microbially induced calcium carbonate precipitation from lab to field scale. PMID:24194735

  8. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium pantothenate, calcium chloride double salt... FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.330 Calcium pantothenate, calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may...

  9. Intracellular calcium buffering capacity in isolated squid axons

    PubMed Central

    Brinley, FJ; Tiffert, T; Scarpa, A; Mullins, LJ

    1977-01-01

    Changes in ionized calcium were studied in axons isolated from living squid by measuring absorbance of the Ca binding dye Arsenazo III using multiwavelength differential absorption spectroscopy. Absorption changes measured in situ were calibrated in vitro with media of ionic composition similar to axoplasm containing CaEGTA buffers. Calcium loads of 50-2,500 μmol/kg axoplasm were induced by microinjection, by stimulation in 112 mM Ca seawater, or by soaking in choline saline with 1-10 mM Ca. Over this range of calcium loading of intact axoplasm, the ionized calcium in the axoplasm rose about 0.6 nM/μM load. Similar loading in axons preteated with carbonyl cyanide 4- trifluoromethoxyphenylhydrazone (FCCP) to inhibit the mitochondrial proton gradient increased ionized calcium by 5-7 percent of the imposed load, i.e. 93-95 percent of the calcium load was buffered by a process insensitive to FCCP. This FCCP- insensitive buffer system was not saturated by the largest calcium loads imposed, indicating a capacity of at least several millimolar. Treatment of previously loaded axons with FCCP or apyrase plus cyanide produced rises in ionized calcium which could be correlated with the extent of the load. Analysis of results indicated that, whereas only 6 percent of the endogenous calcium in fresh axons is stored in the FCCP-sensitive (presumably mitochondrial) buffer system, about 30 percent of an imposed exogenous load in the range of 50-2,500 μM is taken up by this system. PMID:894260

  10. Dietary calcium attenuates platelet aggregation and intracellular Ca2+ mobilization in spontaneously hypertensive rats

    NASA Technical Reports Server (NTRS)

    Otsuka, K.; Watanabe, M.; Yue, Q.; McCarron, D. A.; Hatton, D.

    1997-01-01

    Spontaneously hypertensive rats (SHR) are known to be blood pressure sensitive to dietary calcium. The effects of dietary calcium on platelet aggregation and intracellular Ca2+ mobilization were assessed by turbidimetric methods and fura-2 methods, respectively, in washed platelets of SHR. Ca2+ ATPase activity was examined in aortic membrane fractions. Six weeks of dietary calcium supplementation attenuated the increase of systolic blood pressure (SBP 199 +/- 16 v 170 +/- 9 mm Hg, P < .001) and thrombin-induced platelet aggregation (84.5 +/- 3.7 v 73.7 +/- 7.4%, P < .004) at 9 weeks of age. The ionomycin-induced intracellular calcium ([Ca2+]i) peak in the absence of external Ca2+, which reflects [Ca2+]i storage size, and thrombin-evoked [Ca2+]i release from [Ca2+]i storage were decreased by 2.0% Ca diet (472 +/- 55 v 370 +/- 23 nmol/L, P < .001, 339 +/- 29 v 278 +/- 33 nmol/L, P < .002). In addition, SBP was positively correlated with platelet aggregation (r = 0.703, P = .0088), thrombin-evoked [Ca2+]i (r = 0.739, P = .0044), and ionomycin-induced [Ca2+]i (r = 0.591, P = .0415), respectively. However, there was no significant effect of dietary calcium on Ca2+-ATPase activity in aortic membranes. These results suggest that dietary calcium supplementation had a beneficial effect on platelets of SHR by attenuating [Ca2+]i mobilization from [Ca2+]i storage. The hypotensive effect of dietary calcium might be associated with attenuated [Ca2+]i mobilization in SHR.

  11. Relationship between nutritional habits and hair calcium levels in young women.

    PubMed

    Jeruszka-Bielak, Marta; Brzozowska, Anna

    2011-12-01

    The present study was conducted to investigate whether hair calcium levels are related to nutritional habits, selected status parameters, and life-style factors in young women. Eighty-five healthy female students neither pregnant nor lactating, using no hair dyes or permanents were recruited for the study. Food consumption data, including fortified products and dietary supplements were collected with 4-day records. The calcium levels in hair and serum were analyzed by atomic absorption spectroscopy. Serum osteocalcin and the C-terminal telopeptide of type I collagen were assayed by ELISA. The women were divided into four groups according to their total vitamin D and calcium intakes and hair calcium levels. At adequate calcium intake and comparable serum bone biomarker levels, supplemental vitamin D increased the hair calcium levels. On the other hand, at lower than estimated adequate requirement of vitamin D intake the hair calcium levels were comparable in women with low calcium intakes but consuming high amounts of meat products or those whose diets were rich in dairy products, possibly due to homeostatic mechanisms. Elevated hair calcium was seen in 25% of subjects and could not be related to nutritional or life-style factors. The results show that the hair calcium levels were weakly related to the quality of diet, with some synergistic interactions between nutrients, especially vitamin D and magnesium.

  12. Calcium phosphates: what is the evidence?

    PubMed

    Larsson, Sune

    2010-03-01

    A number of different calcium phosphate compounds such as calcium phosphate cements and solid beta-tricalcium phosphate products have been introduced during the last decade. The chemical composition mimics the mineral phase of bone and as a result of this likeness, the materials seem to be remodeled as for normal bone through a cell-mediated process that involves osteoclastic activity. This is a major difference when compared with, for instance, calcium sulphate compounds that after implantation dissolve irrespective of the new bone formation rate. Calcium phosphates are highly biocompatible and in addition, they act as synthetic osteoconductive scaffolds after implantation in bone. When placed adjacent to bone, osteoid is formed directly on the surface of the calcium phosphate with no soft tissue interposed. Remodeling is slow and incomplete, but by adding more and larger pores, like in ultraporous beta-tricalcium phosphate, complete or nearly complete resorption can be achieved. The indications explored so far include filling of metaphyseal fracture voids or bone cysts, a volume expander in conjunction with inductive products, and as a carrier for various growth factors and antibiotics. Calcium phosphate compounds such as calcium phosphate cement and beta-tricalcium phosphate will most certainly be part of the future armamentarium when dealing with fracture treatment. It is reasonable to believe that we have so far only seen the beginning when it comes to clinical applications.

  13. Despite differences in cytosolic calcium regulation, lidocaine toxicity is similar in adult and neonatal rat dorsal root ganglia in vitro.

    PubMed

    Doan, Lisa V; Eydlin, Olga; Piskoun, Boris; Kline, Richard P; Recio-Pinto, Esperanza; Rosenberg, Andrew D; Blanck, Thomas J J; Xu, Fang

    2014-01-01

    Neuraxial local anesthetics may have neurological complications thought to be due to neurotoxicity. A primary site of action of local anesthetics is the dorsal root ganglia (DRG) neuron. Physiologic differences have been noted between young and adult DRG neurons; hence, the authors examined whether there were any differences in lidocaine-induced changes in calcium and lidocaine toxicity in neonatal and adult rat DRG neurons. DRG neurons were cultured from postnatal day 7 (P7) and adult rats. Lidocaine-induced changes in cytosolic calcium were examined with the calcium indicator Fluo-4. Cells were incubated with varying concentrations of lidocaine and examined for viability using calcein AM and ethidium homodimer-1 staining. Live imaging of caspase-3/7 activation was performed after incubation with lidocaine. The mean KCl-induced calcium transient was greater in P7 neurons (P < 0.05), and lidocaine significantly inhibited KCl-induced calcium responses in both ages (P < 0.05). Frequency distribution histograms of KCl-evoked calcium increases were more heterogeneous in P7 than in adult neurons. With lidocaine, KCl-induced calcium transients in both ages became more homogeneous but remained different between the groups. Interestingly, cell viability was decreased by lidocaine in a dose-dependent manner similarly in both ages. Lidocaine treatment also activated caspase-3/7 in a dose- and time-dependent manner similarly in both ages. Despite physiological differences in P7 and adult DRG neurons, lidocaine cytotoxicity is similar in P7 and adult DRG neurons in vitro. Differences in lidocaine- and KCl-evoked calcium responses suggest the similarity in lidocaine cytotoxicity involves other actions in addition to lidocaine-evoked effects on cytosolic calcium responses.

  14. Despite Differences in Cytosolic Calcium Regulation, Lidocaine Toxicity Is Similar in Adult and Neonatal Rat Dorsal Root Ganglia in Vitro

    PubMed Central

    Doan, Lisa V.; Eydlin, Olga; Piskoun, Boris; Kline, Richard P; Recio-Pinto, Esperanza; Rosenberg, Andrew D; Blanck, Thomas JJ; Xu, Fang

    2013-01-01

    Background Neuraxial local anesthetics may have neurological complications thought to be due to neurotoxicity. A primary site of action for local anesthetics is the dorsal root ganglia (DRG) neuron. Physiologic differences have been noted between young and adult DRG neurons; hence, we examined whether there were differences in lidocaine-induced changes in calcium and lidocaine toxicity in neonatal and adult rat DRG neurons. Methods DRG neurons were cultured from postnatal day 7 (P7) and adult rats. Lidocaine-induced changes in cytosolic calcium were examined with the calcium indicator Fluo-4. Cells were incubated with varying concentrations of lidocaine and examined for viability using calcein AM and ethidium homodimer-1 staining. Live imaging of caspase-3/7 activation was performed after incubation with lidocaine. Results The mean KCl-induced calcium transient was greater in P7 neurons (p < 0.05), and lidocaine significantly inhibited KCl-induced calcium responses in both ages (p < 0.05). Frequency distribution histograms of KCl-evoked calcium increases were more heterogeneous in P7 than in adult neurons. With lidocaine, KCl-induced calcium transients in both ages became more homogeneous but remained different between the groups. Interestingly cell viability was decreased by lidocaine in a dose-dependent manner similarly in both ages. Lidocaine treatment also activated caspase-3/7 in a dose- and time-dependent manner similarly in both ages. Conclusions Despite physiological differences in P7 and adult DRG neurons, lidocaine cytotoxicity is similar in P7 and adult DRG neurons in vitro. Differences in lidocaine- and KCl-evoked calcium responses suggest the similarity in lidocaine cytotoxicity involves other actions in addition to lidocaine-evoked effects on cytosolic calcium responses. PMID:23851347

  15. Attenuating effect of Acorus calamus extract in chronic constriction injury induced neuropathic pain in rats: an evidence of anti-oxidative, anti-inflammatory, neuroprotective and calcium inhibitory effects

    PubMed Central

    2011-01-01

    Background Acorus calamus (family: Araceae), is an indigenous plant, traditionally it is used as an ingredient of various cocktail preparations and for the management of severe inflammatory disorders in Indian system of medicine. Present study investigated the attenuating role of Acorus calamus plant extract in chronic constriction injury (CCI) of sciatic nerve induced peripheral neuropathy in rats. Methods Hot plate, plantar, Randall Selitto, Von Frey Hair, pin prick, acetone drop, photoactometer and rota-rod tests were performed to assess degree of thermal, radiant, mechanical, chemical sensation, spontaneous motor activity and motor co-ordination changes respectively, at different time intervals i.e., day 0, 1, 3, 6, 9, 12, 15, 18 and 21. Tissue myeloperoxidase, superoxide anion and total calcium levels were determined after 21st day to assess biochemical alterations. Histopathological evaluations were also performed. Hydroalcoholic extract of Acorus calamus (HAE-AC, 100 and 200 mg/kg, p.o.) and pregabalin (10 mg/kg, p.o.) were administered from the day of surgery for 14 days. Results CCI of sciatic nerve significantly induced thermal, radiant, mechanical hyperalgesia and thermal, chemical, tactile allodynia, along with increase in the levels of superoxide anion, total calcium and myeloperoxidase activity. Moreover significant histological changes were also observed. HAE-AC attenuated CCI induced development of painful behavioural, biochemical and histological changes in a dose dependent manner similar to that of pregabalin serving as positive control. Conclusions Acorus calamus prevented CCI induced neuropathy which may be attributed to its multiple actions including anti-oxidative, anti-inflammatory, neuroprotective and calcium inhibitory actions. PMID:21426568

  16. The role of calcium in the nuclear maturation of Bufo arenarum oocytes.

    PubMed

    Zelarayán, Liliana I; Toranzo, Graciela Sánchez; Oterino, Julia M; Bühler, Marta I

    2004-02-01

    In Bufo arenarum, progesterone is the physiological maturation inducer. However, in this species, oocytes reinitiate meiosis with no need of an exogenous hormonal stimulus when deprived of their enveloping cell, a phenomenon called spontaneous maturation. We demonstrated that in Bufo arenarum spontaneous maturation occurs only in oocytes obtained during the reproductive period, which can be considered competent to mature spontaneously, in contrast to those in the non-reproductive period, which are incompetent. Interestingly, full-grown Bufo arenarum oocytes always respond to progesterone regardless of the season in which they are obtained. There is a general consensus that both a transient increase in intracellular calcium and a decrease in cAMP-dependent protein kinase activity are the first steps in the mechanisms by which progesterone induces maturation in amphibians. In the present work we analysed the role of calcium in the spontaneous and progesterone-induced maturation of Bufo arenarum oocytes. Results demonstrated that the absence of calcium in the incubation medium or the prevention of Ca(2+) influx by channel blockers such as CdCl2 or NiCl2 did not prevent meiosis reinitiation in either type of maturation. The inhibition of the Ca(2+)-calmodulin complex in no case affected the maturation of the treated oocytes. However, when the oocytes were deprived of calcium by incubation in Ca(2+)-free AR + A23187, meiosis resumption was inhibited. In brief, we demonstrated that in Bufo arenarum the reinitiation of meiosis is a process independent of extracellular calcium at any period of the year and that oocytes require adequate levels of intracellular calcium for germinal vesicle breakdown to occur.

  17. Biotic Nitrogen Enrichment Regulates Calcium Sources to Forests

    NASA Astrophysics Data System (ADS)

    Pett-Ridge, J. C.; Perakis, S. S.; Hynicka, J. D.

    2015-12-01

    Calcium is an essential nutrient in forest ecosystems that is susceptible to leaching loss and depletion. Calcium depletion can affect plant and animal productivity, soil acid buffering capacity, and fluxes of carbon and water. Excess nitrogen supply and associated soil acidification are often implicated in short-term calcium loss from soils, but the long-term role of nitrogen enrichment on calcium sources and resupply is unknown. Here we use strontium isotopes (87Sr/86Sr) as a proxy for calcium to investigate how soil nitrogen enrichment from biological nitrogen fixation interacts with bedrock calcium to regulate both short-term available supplies and the long-term sources of calcium in montane conifer forests. Our study examines 22 sites in western Oregon, spanning a 20-fold range of bedrock calcium on sedimentary and basaltic lithologies. In contrast to previous studies emphasizing abiotic control of weathering as a determinant of long-term ecosystem calcium dynamics and sources (via bedrock fertility, climate, or topographic/tectonic controls) we find instead that that biotic nitrogen enrichment of soil can strongly regulate calcium sources and supplies in forest ecosystems. For forests on calcium-rich basaltic bedrock, increasing nitrogen enrichment causes calcium sources to shift from rock-weathering to atmospheric dominance, with minimal influence from other major soil forming factors, despite regionally high rates of tectonic uplift and erosion that can rejuvenate weathering supply of soil minerals. For forests on calcium-poor sedimentary bedrock, we find that atmospheric inputs dominate regardless of degree of nitrogen enrichment. Short-term measures of soil and ecosystem calcium fertility are decoupled from calcium source sustainability, with fundamental implications for understanding nitrogen impacts, both in natural ecosystems and in the context of global change. Our finding that long-term nitrogen enrichment increases forest reliance on atmospheric

  18. Bone Markers, Calcium Metabolism, and Calcium Kinetics During Extended-Duration Space Flight on the Mir Space Station

    NASA Technical Reports Server (NTRS)

    Smith, Scott M.; Wastney, Meryl E.; O'Brien, Kimberly O.; Morukov, Boris V.; Larina, Irina M.; Abrams, Steven A.; Davis-Street, Janis E.; Oganov, Victor; Shackelford, Linda C.

    2005-01-01

    Bone loss is a current limitation for long-term space exploration. Bone markers, calcitropic hormones, and calcium kinetics of crew members on space missions of 4-6 months were evaluated. Spaceflight-induced bone loss was associated with increased bone resorption and decreased calcium absorption. INTRODUCTION: Bone loss is a significant concern for the health of astronauts on long-duration missions. Defining the time course and mechanism of these changes will aid in developing means to counteract these losses during space flight and will have relevance for other clinical situations that impair weight-bearing activity. MATERIALS AND METHODS: We report here results from two studies conducted during the Shuttle-Mir Science Program. Study 1 was an evaluation of bone and calcium biochemical markers of 13 subjects before and after long-duration (4-6 months) space missions. In study 2, stable calcium isotopes were used to evaluate calcium metabolism in six subjects before, during, and after flight. Relationships between measures of bone turnover, biochemical markers, and calcium kinetics were examined. RESULTS: Pre- and postflight study results confirmed that, after landing, bone resorption was increased, as indicated by increases in urinary calcium (p < 0.05) and collagen cross-links (N-telopeptide, pyridinoline, and deoxypyridinoline were all increased >55% above preflight levels, p < 0.001). Parathyroid hormone and vitamin D metabolites were unchanged at landing. Biochemical markers of bone formation were unchanged at landing, but 2-3 weeks later, both bone-specific alkaline phosphatase and osteocalcin were significantly (p < 0.01) increased above preflight levels. In studies conducted during flight, bone resorption markers were also significantly higher than before flight. The calcium kinetic data also validated that bone resorption was increased during flight compared with preflight values (668 +/- 130 versus 427 +/- 153 mg/day; p < 0.001) and clearly documented that

  19. Cross talk among calcium, hydrogen peroxide, and nitric oxide and activation of gene expression involving calmodulins and calcium-dependent protein kinases in Ulva compressa exposed to copper excess.

    PubMed

    González, Alberto; Cabrera, M de Los Ángeles; Henríquez, M Josefa; Contreras, Rodrigo A; Morales, Bernardo; Moenne, Alejandra

    2012-03-01

    To analyze the copper-induced cross talk among calcium, nitric oxide (NO), and hydrogen peroxide (H(2)O(2)) and the calcium-dependent activation of gene expression, the marine alga Ulva compressa was treated with the inhibitors of calcium channels, ned-19, ryanodine, and xestospongin C, of chloroplasts and mitochondrial electron transport chains, 3-(3,4-dichlorophenyl)-1,1-dimethylurea and antimycin A, of pyruvate dehydrogenase, moniliformin, of calmodulins, N-(6-aminohexyl)-5-chloro-1-naphtalene sulfonamide, and of calcium-dependent protein kinases, staurosporine, as well as with the scavengers of NO, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, and of H(2)O(2), ascorbate, and exposed to a sublethal concentration of copper (10 μm) for 24 h. The level of NO increased at 2 and 12 h. The first peak was inhibited by ned-19 and 3-(2,3-dichlorophenyl)-1,1-dimethylurea and the second peak by ned-19 and antimycin A, indicating that NO synthesis is dependent on calcium release and occurs in organelles. The level of H(2)O(2) increased at 2, 3, and 12 h and was inhibited by ned-19, ryanodine, xestospongin C, and moniliformin, indicating that H(2)O(2) accumulation is dependent on calcium release and Krebs cycle activity. In addition, pyruvate dehydrogenase, 2-oxoxglutarate dehydrogenase, and isocitrate dehydrogenase activities of the Krebs cycle increased at 2, 3, 12, and/or 14 h, and these increases were inhibited in vitro by EGTA, a calcium chelating agent. Calcium release at 2, 3, and 12 h was inhibited by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide and ascorbate, indicating activation by NO and H(2)O(2). In addition, the level of antioxidant protein gene transcripts decreased with N-(6-aminohexyl)-5-chloro-1-naphtalene sulfonamide and staurosporine. Thus, there is a copper-induced cross talk among calcium, H(2)O(2), and NO and a calcium-dependent activation of gene expression involving calmodulins and calcium-dependent protein

  20. (−)-Epicatechin induces calcium and translocation independent eNOS activation in arterial endothelial cells

    PubMed Central

    Ramirez-Sanchez, Israel; Maya, Lisandro; Ceballos, Guillermo

    2011-01-01

    The consumption of cacao-derived (i.e., cocoa) products provides beneficial cardiovascular effects in healthy subjects as well as individuals with endothelial dysfunction such as smokers, diabetics, and postmenopausal women. The vascular actions of cocoa are related to enhanced nitric oxide (NO) production. These actions can be reproduced by the administration of the cacao flavanol (−)-epicatechin (EPI). To further understand the mechanisms behind the vascular action of EPI, we investigated the effects of Ca2+ depletion on endothelial nitric oxide (NO) synthase (eNOS) activation/phosphorylation and translocation. Human coronary artery endothelial cells were treated with EPI or with bradykinin (BK), a well-known Ca2+-dependent eNOS activator. Results demonstrate that both EPI and BK induce increases in intracellular calcium and NO levels. However, under Ca2+-free conditions, EPI (but not BK) is still capable of inducing NO production through eNOS phosphorylation at serine 615, 633, and 1177. Interestingly, EPI-induced translocation of eNOS from the plasmalemma was abolished upon Ca2+ depletion. Thus, under Ca2+-free conditions, EPI can stimulate NO synthesis independent of calmodulin binding to eNOS and of its translocation into the cytoplasm. We also examined the effect of EPI on the NO/cGMP/vasodilator-stimulated phosphoprotein (VASP) pathway activation in isolated Ca2+-deprived canine mesenteric arteries. Results demonstrate that under these conditions, EPI induces the activation of this vasorelaxation-related pathway and that this effect is inhibited by pretreatment with nitro-l-arginine methyl ester, suggesting a functional relevance for this phenomenon. PMID:21209365

  1. Hysteresis effect implicates calcium cycling as a mechanism of repolarization alternans.

    PubMed

    Walker, Mariah L; Wan, Xiaoping; Kirsch, Glenn E; Rosenbaum, David S

    2003-11-25

    T-wave alternans is due to alternation of membrane repolarization at the cellular level and is a risk factor for sudden cardiac death. Recently, a hysteresis effect has been reported in patients whereby T-wave alternans, once induced by rapid heart rate, persists even when heart rate is subsequently slowed. We hypothesized that alternans hysteresis is an intrinsic property of cardiac myocytes, directly related to an underlying mechanism for repolarization alternans that involves intracellular calcium cycling. Stepwise pacing was used to induce alternans in Langendorff-perfused guinea pig hearts from which optical action potentials were recorded simultaneously at 256 ventricular sites with voltage-sensitive dyes and in whole-cell patch-clamped cardiac myocytes treated with or without BAPTA-AM (1,2-bis[2-aminophenoxy]ethane-N,N,N',N'-tetraacetic acid tetrakis [acetoxymethyl ester]). Alternans hysteresis was observed in every isolated heart: threshold heart rate for alternans was 280+/-12 bpm, but during subsequent deceleration of pacing, alternans persisted to significantly slower heart rates (238+/-5 bpm, P<0.05). Optical mapping showed that this effect also applied to the threshold for spatially discordant alternans (313+/-2.2 bpm during acceleration versus 250+/-6.6 bpm during deceleration, P<0.05). Alternans hysteresis was also observed in isolated cardiac myocytes. Moreover, calcium chelation by BAPTA-AM raised the threshold for alternans and inhibited hysteresis in a dose-dependent manner with no effect on baseline action potential duration. Alternans hysteresis is an intrinsic property of cardiac myocytes that can lead to persistence of arrhythmogenic discordant alternans even after heart rate is slowed. These results also support an important underlying role of calcium cycling in the mechanism of alternans.

  2. Calcium dependent and independent cytokine synthesis by air pollution particle-exposed human bronchial epithelial cells

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

    Sakamoto, Noriho; Hayashi, Shizu; Gosselink, John

    2007-12-01

    Exposure to ambient air pollution particles with a diameter of < 10 {mu}m (PM{sub 10}) has been associated with increased cardiopulmonary morbidity and mortality. We have shown that human bronchial epithelial cells (HBECs) exposed to PM{sub 10} produce pro-inflammatory mediators that contribute to a local and systemic inflammatory response. Changes in intracellular calcium concentrations ([Ca{sup 2+}]{sub i}) have been demonstrated to regulate several functions of the airway epithelium including the production of pro-inflammatory mediators. The aim of the present study was to determine the nature and mechanism of calcium responses induced by PM{sub 10} in HBECs and its relationship tomore » cytokine synthesis. Methods: Primary HBECs were exposed to urban air pollution particles (EHC-93) and [Ca{sup 2+}]{sub i} responses were measured using the fluoroprobe (Fura-2). Cytokine levels were measured at mRNA and protein levels using real-time PCR and ELISA. Results: PM{sub 10} increased [Ca{sup 2+}]{sub i} in a dose-dependent manner. This calcium response was reduced by blocking the influx of calcium into cells (i.e. calcium-free medium, NiCl{sub 2}, LaCl{sub 3}). PM{sub 10} also decreased the activity of calcium pumps. PM{sub 10} increased the production of IL-1{beta}, IL-8, GM-CSF and LIF. Preincubation with intracellular calcium chelator (BAPTA-AM) attenuated IL-1{beta} and IL-8 production, but not GM-CSF and LIF production. Conclusion: We conclude that exposure to PM{sub 10} induces an increase in cytosolic calcium and cytokine production in bronchial epithelial cells. Our results also suggest that PM{sub 10} induces the production of pro-inflammatory mediators via either intracellular calcium-dependent (IL-1{beta}, IL-8) or -independent (GM-CSF, LIF) pathways.« less

  3. Dysbalance of Astrocyte Calcium under Hyperammonemic Conditions

    PubMed Central

    Haack, Nicole; Dublin, Pavel; Rose, Christine R.

    2014-01-01

    Increased brain ammonium (NH4 +/NH3) plays a central role in the manifestation of hepatic encephalopathy (HE), a complex syndrome associated with neurological and psychiatric alterations, which is primarily a disorder of astrocytes. Here, we analysed the influence of NH4 +/NH3 on the calcium concentration of astrocytes in situ and studied the underlying mechanisms of NH4 +/NH3-evoked calcium changes, employing fluorescence imaging with Fura-2 in acute tissue slices derived from different regions of the mouse brain. In the hippocampal stratum radiatum, perfusion with 5 mM NH4 +/NH3 for 30 minutes caused a transient calcium increase in about 40% of astrocytes lasting about 10 minutes. Furthermore, the vast majority of astrocytes (∼90%) experienced a persistent calcium increase by ∼50 nM. This persistent increase was already evoked at concentrations of 1–2 mM NH4 +/NH3, developed within 10–20 minutes and was maintained as long as the NH4 +/NH3 was present. Qualitatively similar changes were observed in astrocytes of different neocortical regions as well as in cerebellar Bergmann glia. Inhibition of glutamine synthetase resulted in significantly larger calcium increases in response to NH4 +/NH3, indicating that glutamine accumulation was not a primary cause. Calcium increases were not mimicked by changes in intracellular pH. Pharmacological inhibition of voltage-gated sodium channels, sodium-potassium-chloride-cotransporters (NKCC), the reverse mode of sodium/calcium exchange (NCX), AMPA- or mGluR5-receptors did not dampen NH4 +/NH3-induced calcium increases. They were, however, significantly reduced by inhibition of NMDA receptors and depletion of intracellular calcium stores. Taken together, our measurements show that sustained exposure to NH4 +/NH3 causes a sustained increase in intracellular calcium in astrocytes in situ, which is partly dependent on NMDA receptor activation and on release of calcium from intracellular stores. Our study furthermore suggests

  4. Calcium signaling in neuronal cells exposed to the munitions compound Cyclotrimethylenetrinitramine (RDX).

    PubMed

    Ehrich, Marion; Wu, Xiaohua; Werre, Stephen R; Major, Michael A; McCain, Wilfred C; Reddy, Gunda

    2009-01-01

    Cyclotrimethylenetrinitramine (RDX) has been used extensively as an explosive in military munitions. Mechanisms for seizure production, seen in past animal studies, have not been described. Increased calcium levels contribute to excitotoxicity, so in this study neuroblastoma cells are loaded with calcium-indicating dye before application of 1.5 microM to 7.5 mM RDX, with fluorescence recorded for 30 cycles of 11 seconds each. The lowest concentration of RDX increases calcium fluorescence significantly above baseline for cycles 2 to 8; millimolar concentrations increase calcium fluorescence significantly above baseline for cycles 2 to 30. Increases in calcium, like those of 200 nM carbachol, are prevented with 10 mM of calcium chelator ethylene glycol-bis(beta-aminoethyl ether)-N,N,N,N tetra-acetic acid (EGTA, tetrasodium salt). Calcium channel blocker verapamil (20 microM), Ca(2+)-ATPase inhibitor thapsigargin (5 microM), and general membrane stabilizer lidocaine (10 mM) partially attenuate carbachol- and RDX-induced increases in calcium, suggesting that RDX transiently increases intracellular calcium by multiple mechanisms.

  5. Calcium homeostasis during oral glucose load in healthy women.

    PubMed

    D'Erasmo, E; Pisani, D; Ragno, A; Raejntroph, N; Vecci, E; Acca, M

    1999-04-01

    It has been demonstrated that in healthy subjects during oral glucose tolerance test, serum calcium declines, while urinary calcium excretion increases, even if there is not a general agreement in this regard. The study was carried out in order to evaluate the effects of glucose oral load on calcium homeostasis in eight healthy adult women, also considering ionized calcium, plasma insulin and parathyroid hormone changes. The results showed a decline of total and ionized serum calcium (p < 0.05 and p < 0.01, respectively; maximum of the decrease at time 120'), in parallel with the increase of urinary calcium/ creatinine ratio (p < 0.05). Serum glucose and insulin increase (p < 0.0001 and p < 0.0005 respectively; maximum value at time 60'), while the parathyroid hormone level decreases (maximum decline at time 120', p < 0.01). No changes were observed in fasting control subjects for all parameters considered. The changes of these parameters with time suggest that the effects of glucose oral load on calcium metabolism in healthy adult women may be the consequence of parathyroid hormone suppression induced by acute hyperglycemia/hyperinsulinemia. The results confirm in vivo the PTH behaviour in vitro, on cultured bovine parathyroid cells, with high glucose concentration.

  6. Identification of a Calcium Signalling Pathway of S-[6]-Gingerol in HuH-7 Cells.

    PubMed

    Li, Xiao-Hong; McGrath, Kristine C Y; Tran, Van H; Li, Yi-Ming; Mandadi, Sravan; Duke, Colin C; Heather, Alison K; Roufogalis, Basil D

    2013-01-01

    Calcium signals in hepatocytes control cell growth, proliferation, and death. Members of the transient receptor potential (TRP) cation channel superfamily are candidate calcium influx channels. NF κ B activation strictly depends on calcium influx and often induces antiapoptotic genes favouring cell survival. Previously, we reported that S-[6]-gingerol is an efficacious agonist of the transient receptor potential cation channel subfamily V member 1 (TRPV1) in neurones. In this study, we tested the effect of S-[6]-gingerol on HuH-7 cells using the Fluo-4 calcium assay, RT-qPCR, transient cell transfection, and luciferase measurements. We found that S-[6]-gingerol induced a transient rise in [Ca(2+)] i in HuH-7 cells. The increase in [Ca(2+)] i induced by S-[6]-gingerol was abolished by preincubation with EGTA and was also inhibited by the TRPV1 channel antagonist capsazepine. Expression of TRPV1 in HuH-7 cells was confirmed by mRNA analysis as well as a test for increase of [Ca(2+)] i by TRPV1 agonist capsaicin and its inhibition by capsazepine. We found that S-[6]-gingerol induced rapid NF κ B activation through TRPV1 in HuH-7 cells. Furthermore, S-[6]-gingerol-induced NF κ B activation was dependent on the calcium gradient and TRPV1. The rapid NF κ B activation by S-[6]-gingerol was associated with an increase in mRNA levels of NF κ B-target genes: cIAP-2, XIAP, and Bcl-2 that encode antiapoptotic proteins.

  7. The effect of radiopacifiers agents on pH, calcium release, radiopacity, and antimicrobial properties of different calcium hydroxide dressings.

    PubMed

    Ordinola-Zapata, Ronald; Bramante, Clovis Monteiro; García-Godoy, Franklin; Moldauer, Bertram Ivan; Gagliardi Minotti, Paloma; Tercília Grizzo, Larissa; Duarte, Marco Antonio Hungaro

    2015-07-01

    The aim of this study was to evaluate the antimicrobial activity, pH level, calcium ion release, and radiopacity of calcium hydroxide pastes associated with three radiopacifying agents (iodoform, zinc oxide, and barium sulfate). For the pH and calcium release tests, 45 acrylic teeth were utilized and immersed in ultrapure water. After 24 h, 72 h, and 7 days the solution was analyzed by using a pH meter and an atomic absorption spectrophotometer. Polyethylene tubes filled with the pastes were used to perform the radiopacity test. For the antimicrobial test, 25 dentin specimens were infected intraorally in order to induce the biofilm colonization and treated with the pastes for 7 days. The Live/Dead technique and a confocal microscope were used to obtain the ratio of live cells. Parametric and nonparametric statistical tests were performed to show differences among the groups (P < 0.05). The pH analysis at 7 days showed significant differences (P < 0.05) among the groups. No differences among the pastes were found in the calcium release test on the 7th day (P > 0.05). The calcium hydroxide/iodoform samples had the highest radiopacity and antimicrobial activity against the biofilm-infected dentin in comparison to the other pastes (P < 0.05). Calcium hydroxide mixed with 17% iodoform and 35% propylene glycol into a paste had the highest pH, calcium ion release, radiopacity, and the greatest antimicrobial action versus similar samples mixed with BaSO4 or ZnO. © 2015 Wiley Periodicals, Inc.

  8. Application of factor analysis of infrared spectra for quantitative determination of beta-tricalcium phosphate in calcium hydroxylapatite.

    PubMed

    Arsenyev, P A; Trezvov, V V; Saratovskaya, N V

    1997-01-01

    This work represents a method, which allows to determine phase composition of calcium hydroxylapatite basing on its infrared spectrum. The method uses factor analysis of the spectral data of calibration set of samples to determine minimal number of factors required to reproduce the spectra within experimental error. Multiple linear regression is applied to establish correlation between factor scores of calibration standards and their properties. The regression equations can be used to predict the property value of unknown sample. The regression model was built for determination of beta-tricalcium phosphate content in hydroxylapatite. Statistical estimation of quality of the model was carried out. Application of the factor analysis on spectral data allows to increase accuracy of beta-tricalcium phosphate determination and expand the range of determination towards its less concentration. Reproducibility of results is retained.

  9. PCV2 induces apoptosis and modulates calcium homeostasis in piglet lymphocytes in vitro.

    PubMed

    Lv, Yingjun; Dai, Lei; Han, Huili; Zhang, Shuxia

    2012-12-01

    This study investigated the process of PCV2-induced apoptosis and the effect of PCV2 inoculation on calcium homeostasis in piglet lymphocytes in vitro. PCV2-inoculated lymphocytes exhibited chromatin condensation, chromatin segregation, the appearance of membrane-enclosed apoptotic bodies, and DNA fragmentation. Moreover, the proportion of apoptotic cells increased significantly in PCV2-inoculated lymphocytes compared with controls. These results demonstrate that PCV2 induces lymphocyte apoptosis. Some evidence suggests that an alteration in the intracellular free Ca2+ concentration ([Ca2+]i) could cause apoptosis. We measured elevated [Ca2+]i in PCV2-inoculated lymphocytes for 12 or 24 h compared with controls. Our results support that PCV2-induced apoptosis may be relative to [Ca2+]i. In addition, calmodulin (CaM) was increased in PCV2-inoculated lymphocytes for 12 h compared with controls. The amount of CaM-dependent protein kinase II (CaMKII) did not change with PCV2 inoculation. We infer that the increased [Ca2+]i can bind CaM protein, but functions independently of CaMKII. Inositol 1,4,5-trisphosphate receptor (IP3R)-1 mRNA expression increased with PCV2 inoculation, whereas plasma Ca2+-ATP4 mRNA expression decreased. A decreased Ca2+-ATP4 level may inhibit Ca2+ efflux, and the increased IP3R-1 may trigger Ca2+ release from the endoplasmic reticulum. Both of these changes may contribute to increased [Ca2+]i. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. L-type calcium channel blockade attenuates morphine withdrawal: in vivo interaction between L-type calcium channels and corticosterone.

    PubMed

    Esmaeili-Mahani, Saeed; Fathi, Yadollah; Motamedi, Fereshteh; Hosseinpanah, Farhad; Ahmadiani, Abolhassan

    2008-02-01

    Both opioids and calcium channel blockers could affect hypothalamic-pituitary-adrenal (HPA) axis function. Nifedipine, as a calcium channel blocker, can attenuate the development of morphine dependence; however, the role of the HPA axis in this effect has not been elucidated. We examined the effect of nifedipine on the induction of morphine dependency in intact and adrenalectomized (ADX) male rats, as assessed by the naloxone precipitation test. We also evaluated the effect of this drug on HPA activity induced by naloxone. Our results showed that despite the demonstration of dependence in both groups of rats, nifedipine is more effective in preventing of withdrawal signs in ADX rats than in sham-operated rats. In groups that received morphine and nifedipine concomitantly, naloxone-induced corticosterone secretion was attenuated. Thus, we have shown the involvement of the HPA axis in the effect of nifedipine on the development of morphine dependency and additionally demonstrated an in vivo interaction between the L-type Ca2+ channels and corticosterone.

  11. Generation of a Homozygous Transgenic Rat Strain Stably Expressing a Calcium Sensor Protein for Direct Examination of Calcium Signaling.

    PubMed

    Szebényi, Kornélia; Füredi, András; Kolacsek, Orsolya; Pergel, Enikő; Bősze, Zsuzsanna; Bender, Balázs; Vajdovich, Péter; Tóvári, József; Homolya, László; Szakács, Gergely; Héja, László; Enyedi, Ágnes; Sarkadi, Balázs; Apáti, Ágota; Orbán, Tamás I

    2015-08-03

    In drug discovery, prediction of selectivity and toxicity require the evaluation of cellular calcium homeostasis. The rat is a preferred laboratory animal for pharmacology and toxicology studies, while currently no calcium indicator protein expressing rat model is available. We established a transgenic rat strain stably expressing the GCaMP2 fluorescent calcium sensor by a transposon-based methodology. Zygotes were co-injected with mRNA of transposase and a CAG-GCaMP2 expressing construct, and animals with one transgene copy were pre-selected by measuring fluorescence in blood cells. A homozygous rat strain was generated with high sensor protein expression in the heart, kidney, liver, and blood cells. No pathological alterations were found in these animals, and fluorescence measurements in cardiac tissue slices and primary cultures demonstrated the applicability of this system for studying calcium signaling. We show here that the GCaMP2 expressing rat cardiomyocytes allow the prediction of cardiotoxic drug side-effects, and provide evidence for the role of Na(+)/Ca(2+) exchanger and its beneficial pharmacological modulation in cardiac reperfusion. Our data indicate that drug-induced alterations and pathological processes can be followed by using this rat model, suggesting that transgenic rats expressing a calcium-sensitive protein provide a valuable system for pharmacological and toxicological studies.

  12. Generation of a Homozygous Transgenic Rat Strain Stably Expressing a Calcium Sensor Protein for Direct Examination of Calcium Signaling

    PubMed Central

    Szebényi, Kornélia; Füredi, András; Kolacsek, Orsolya; Pergel, Enikő; Bősze, Zsuzsanna; Bender, Balázs; Vajdovich, Péter; Tóvári, József; Homolya, László; Szakács, Gergely; Héja, László; Enyedi, Ágnes; Sarkadi, Balázs; Apáti, Ágota; Orbán, Tamás I.

    2015-01-01

    In drug discovery, prediction of selectivity and toxicity require the evaluation of cellular calcium homeostasis. The rat is a preferred laboratory animal for pharmacology and toxicology studies, while currently no calcium indicator protein expressing rat model is available. We established a transgenic rat strain stably expressing the GCaMP2 fluorescent calcium sensor by a transposon-based methodology. Zygotes were co-injected with mRNA of transposase and a CAG-GCaMP2 expressing construct, and animals with one transgene copy were pre-selected by measuring fluorescence in blood cells. A homozygous rat strain was generated with high sensor protein expression in the heart, kidney, liver, and blood cells. No pathological alterations were found in these animals, and fluorescence measurements in cardiac tissue slices and primary cultures demonstrated the applicability of this system for studying calcium signaling. We show here that the GCaMP2 expressing rat cardiomyocytes allow the prediction of cardiotoxic drug side-effects, and provide evidence for the role of Na+/Ca2+ exchanger and its beneficial pharmacological modulation in cardiac reperfusion. Our data indicate that drug-induced alterations and pathological processes can be followed by using this rat model, suggesting that transgenic rats expressing a calcium-sensitive protein provide a valuable system for pharmacological and toxicological studies. PMID:26234466

  13. Hydrogen peroxide homeostasis: activation of plant catalase by calcium/calmodulin

    NASA Technical Reports Server (NTRS)

    Yang, T.; Poovaiah, B. W.

    2002-01-01

    Environmental stimuli such as UV, pathogen attack, and gravity can induce rapid changes in hydrogen peroxide (H(2)O(2)) levels, leading to a variety of physiological responses in plants. Catalase, which is involved in the degradation of H(2)O(2) into water and oxygen, is the major H(2)O(2)-scavenging enzyme in all aerobic organisms. A close interaction exists between intracellular H(2)O(2) and cytosolic calcium in response to biotic and abiotic stresses. Studies indicate that an increase in cytosolic calcium boosts the generation of H(2)O(2). Here we report that calmodulin (CaM), a ubiquitous calcium-binding protein, binds to and activates some plant catalases in the presence of calcium, but calcium/CaM does not have any effect on bacterial, fungal, bovine, or human catalase. These results document that calcium/CaM can down-regulate H(2)O(2) levels in plants by stimulating the catalytic activity of plant catalase. Furthermore, these results provide evidence indicating that calcium has dual functions in regulating H(2)O(2) homeostasis, which in turn influences redox signaling in response to environmental signals in plants.

  14. Mechanics regulates ATP-stimulated collective calcium response in fibroblast cells

    PubMed Central

    Lembong, Josephine; Sabass, Benedikt; Sun, Bo; Rogers, Matthew E.; Stone, Howard A.

    2015-01-01

    Cells constantly sense their chemical and mechanical environments. We study the effect of mechanics on the ATP-induced collective calcium response of fibroblast cells in experiments that mimic various tissue environments. We find that closely packed two-dimensional cell cultures on a soft polyacrylamide gel (Young's modulus E = 690 Pa) contain more cells exhibiting calcium oscillations than cultures on a rigid substrate (E = 36 000 Pa). Calcium responses of cells on soft substrates show a slower decay of calcium level relative to those on rigid substrates. Actin enhancement and disruption experiments for the cell cultures allow us to conclude that actin filaments determine the collective Ca2+ oscillatory behaviour in the culture. Inhibition of gap junctions results in a decrease of the oscillation period and reduced correlation of calcium responses, which suggests additional complexity of signalling upon cell–cell contact. Moreover, the frequency of calcium oscillations is independent of the rigidity of the substrate but depends on ATP concentration. We compare our results with those from similar experiments on individual cells. Overall, our observations show that collective chemical signalling in cell cultures via calcium depends critically on the mechanical environment. PMID:26063818

  15. Calcium deprivation increases the palatability of calcium solutions in rats.

    PubMed

    McCaughey, Stuart A; Forestell, Catherine A; Tordoff, Michael G

    2005-02-15

    Calcium-deprived rats have elevated intakes of CaCl2, other calcium salts, and some non-calcium compounds. We used taste reactivity to examine the effects of calcium deprivation on the palatability of CaCl2 and other solutions. Nine male Sprague-Dawley rats were calcium-deprived by maintenance on a low-calcium diet, and eight replete rats were used as controls. All rats were videotaped during intraoral infusion of the following solutions: 30 and 300 mM CaCl2, 30 mM calcium lactate, 100 and 600 mM NaCl, 30 mM MgCl2, 1 mM quinine.HCl, 2.5 mM sodium saccharin, and deionized water. We counted individual orofacial and somatic movements elicited by the infusions and used them to calculate total ingestive and aversive scores. Relative to controls, calcium-deprived rats gave a significantly larger number of tongue protrusions and had higher total ingestive scores for CaCl2, calcium lactate, NaCl, and MgCl2. Our results suggest that CaCl2, calcium lactate, NaCl, and MgCl2 taste more palatable to rats when they are calcium-deprived than replete, and this may be responsible for the increased intake of these solutions following calcium deprivation.

  16. Calcium and cAMP directly modulate the speed of the Drosophila circadian clock.

    PubMed

    Palacios-Muñoz, Angelina; Ewer, John

    2018-06-01

    Circadian clocks impose daily periodicities to animal behavior and physiology. At their core, circadian rhythms are produced by intracellular transcriptional/translational feedback loops (TTFL). TTFLs may be altered by extracellular signals whose actions are mediated intracellularly by calcium and cAMP. In mammals these messengers act directly on TTFLs via the calcium/cAMP-dependent transcription factor, CREB. In the fruit fly, Drosophila melanogaster, calcium and cAMP also regulate the periodicity of circadian locomotor activity rhythmicity, but whether this is due to direct actions on the TTFLs themselves or are a consequence of changes induced to the complex interrelationship between different classes of central pacemaker neurons is unclear. Here we investigated this question focusing on the peripheral clock housed in the non-neuronal prothoracic gland (PG), which, together with the central pacemaker in the brain, controls the timing of adult emergence. We show that genetic manipulations that increased and decreased the levels of calcium and cAMP in the PG caused, respectively, a shortening and a lengthening of the periodicity of emergence. Importantly, knockdown of CREB in the PG caused an arrhythmic pattern of eclosion. Interestingly, the same manipulations directed at central pacemaker neurons caused arrhythmicity of eclosion and of adult locomotor activity, suggesting a common mechanism. Our results reveal that the calcium and cAMP pathways can alter the functioning of the clock itself. In the PG, these messengers, acting as outputs of the clock or as second messengers for stimuli external to the PG, could also contribute to the circadian gating of adult emergence.

  17. Phototropins function in high-intensity blue light-induced hypocotyl phototropism in Arabidopsis by altering cytosolic calcium.

    PubMed

    Zhao, Xiang; Wang, Yan-Liang; Qiao, Xin-Rong; Wang, Jin; Wang, Lin-Dan; Xu, Chang-Shui; Zhang, Xiao

    2013-07-01

    Phototropins (phot1 and phot2), the blue light receptors in plants, regulate hypocotyl phototropism in a fluence-dependent manner. Especially under high fluence rates of blue light (HBL), the redundant function mediated by both phot1 and phot2 drastically restricts the understanding of the roles of phot2. Here, systematic analysis of phototropin-related mutants and overexpression transgenic lines revealed that HBL specifically induced a transient increase in cytosolic Ca(2+) concentration ([Ca(2+)]cyt) in Arabidopsis (Arabidopsis thaliana) hypocotyls and that the increase in [Ca(2+)]cyt was primarily attributed to phot2. Pharmacological and genetic experiments illustrated that HBL-induced Ca(2+) increases were modulated differently by phot1 and phot2. Phot2 mediated the HBL-induced increase in [Ca(2+)]cyt mainly by an inner store-dependent Ca(2+)-release pathway, not by activating plasma membrane Ca(2+) channels. Further analysis showed that the increase in [Ca(2+)]cyt was possibly responsible for HBL-induced hypocotyl phototropism. An inhibitor of auxin efflux carrier exhibited significant inhibitions of both phototropism and increases in [Ca(2+)]cyt, which indicates that polar auxin transport is possibly involved in HBL-induced responses. Moreover, PHYTOCHROME KINASE SUBSTRATE1 (PKS1), the phototropin-related signaling element identified, interacted physically with phototropins, auxin efflux carrier PIN-FORMED1 and calcium-binding protein CALMODULIN4, in vitro and in vivo, respectively, and HBL-induced phototropism was impaired in pks multiple mutants, indicating the role of the PKS family in HBL-induced phototropism. Together, these results provide new insights into the functions of phototropins and highlight a potential integration point through which Ca(2+) signaling-related HBL modulates hypocotyl phototropic responses.

  18. Dispersed-Fluorescence Spectroscopy of Jet-Cooled Calcium Ethoxide Radical (CaOC_2H_5)

    NASA Astrophysics Data System (ADS)

    Paul, Anam C.; Reza, Md Asmaul; Liu, Jinjun

    2016-06-01

    Metal-containing free radicals are important intermediates in metal-surface reactions and in the interaction between metals and organic molecules. In the present work, dispersed fluorescence (DF) spectra of the calcium ethoxide radical (CaOC_2H_5) have been obtained by pumping the {tilde A^2}{A}' ← {tilde X^2}{A}' and the {tilde B^2}{A}'' ← {tilde X^2}{A}' origin bands in its laser-induced fluorescence (LIF) spectrum. CaOC_2H_5 radicals were produced by 1064 nm laser ablation of calcium grains in the presence of ethanol under jet-cooled conditions. Dominant transitions in the vibrationally resolved DF spectra are well reproduced using Franck-Condon factors predicted by complete active space self-consistent (CASSCF) calculations. Differences in transition intensities between the {tilde A^2}{A}' → {tilde X^2}{A}' and the {tilde B^2}{A}'' → {tilde X^2}{A}' DF spectra are attributed to the pseudo-Jahn-Teller interaction between the tilde A ^2 A' and the tilde B ^2 A'' states. Collision-induced population transfer between these two excited electronic states results in additional peaks in the DF spectra.

  19. Calcium-activated potassium channels in insect pacemaker neurons as unexpected target site for the novel fumigant dimethyl disulfide.

    PubMed

    Gautier, Hélène; Auger, Jacques; Legros, Christian; Lapied, Bruno

    2008-01-01

    Dimethyl disulfide (DMDS), a plant-derived insecticide, is a promising fumigant as a substitute for methyl bromide. To further understand the mode of action of DMDS, we examined its effect on cockroach octopaminergic neurosecretory cells, called dorsal unpaired median (DUM) neurons, using whole-cell patch-clamp technique, calcium imaging and antisense oligonucleotide strategy. At low concentration (1 microM), DMDS modified spontaneous regular spike discharge into clear bursting activity associated with a decrease of the amplitude of the afterhyperpolarization. This effect led us to suspect alterations of calcium-activated potassium currents (IKCa) and [Ca(2+)](i) changes. We showed that DMDS reduced amplitudes of both peak transient and sustained components of the total potassium current. IKCa was confirmed as a target of DMDS by using iberiotoxin, cadmium chloride, and pSlo antisense oligonucleotide. In addition, we showed that DMDS induced [Ca(2+)](i) rise in Fura-2-loaded DUM neurons. Using calcium-free solution, and (R,S)-(3,4-dihydro-6,7-dimethoxy-isoquinoline-1-yl)-2-phenyl-N,N-di-[2-(2,3,4-trimethoxy-phenyl)ethyl]-acetamide (LOE 908) [an inhibitor of transient receptor potential (TRP)gamma], we demonstrated that TRPgamma initiated calcium influx. By contrast, omega-conotoxin GVIA (an inhibitor of N-type high-voltage-activated calcium channels), did not affect the DMDS-induced [Ca(2+)](i) rise. Finally, the participation of the calcium-induced calcium release mechanism was investigated using thapsigargin, caffeine, and ryanodine. Our study revealed that DMDS-induced elevation in [Ca(2+)](i) modulated IKCa in an unexpected bell-shaped manner via intracellular calcium. In conclusion, DMDS affects multiple targets, which could be an effective way to improve pest control efficacy of fumigation.

  20. Phenylethylamine induces an increase in cytosolic Ca2+ in yeast.

    PubMed

    Pinontoan, Reinhard; Krystofova, Svetlana; Kawano, Tomonori; Mori, Izumi C; Tsuji, Frederick I; Iida, Hidetoshi; Muto, Shoshi

    2002-05-01

    Beta-phenylethylamine (PEA) induced an increase in cytosolic free calcium ion concentration ([Ca2+]c) in Saccharomyces cerevisiae cells monitored with transgenic aequorin, a Ca2+-dependent photoprotein. The PEA-induced [Ca2+]c increase was dependent on the concentrations of PEA applied, and the Ca2+ mostly originated from an extracellular source. Preceding the Ca2+ influx, H2O2 was generated in the cells by the addition of PEA. Externally added H2O2 also induced a [Ca2+]c increase. These results suggest that PEA induces the [Ca2+]c increase via H2O2 generation. The PEA-induced [Ca2+]c increase occurred in the mid1 mutant with a slightly smaller peak than in the wild-type strain, indicating that Mid1, a stretch-activated nonselective cation channel, may not be mainly involved in the PEA-induced Ca2+ influx. When PEA was applied, the MATa mid1 mutant was rescued from alpha-factor-induced death in a Ca2+-limited medium, suggesting that the PEA-induced [Ca2+]c increase can reinforce calcium signaling in the mating pheromone response pathway.

  1. Calcium ionization balance and argon/calcium abundance in solar flares

    NASA Astrophysics Data System (ADS)

    Antonucci, E.; Marocchi, D.; Gabriel, A. H.; Doschek, G. A.

    1987-12-01

    An earlier analysis of solar flare calcium spectra from XRP and P78-1 aimed at measuring the calcium ionization balance resulted in an ambiguity due to a line blend between the calcium q line and an Ar XVII line. In the present work the calcium line 'r' is included in the analysis in order to resolve this problem. It is shown that the correct calcium ionization balance is that indicated in the earlier paper as corresponding to an argon/calcium abundance ratio of 0.2. The argon/calcium abundance ratio in the group of solar flares studied is shown to be 0.2 + or - 0.2. It is further argued that while the abundance of heavy elements may be enhanced in energetic flare events, this enhancement is less for argon than for calcium, leading to an argon/calcium ratio smaller than that present in the quiet sun.

  2. Calcium sulphate in ammonium sulphate solution

    USGS Publications Warehouse

    Sullivan, E.C.

    1905-01-01

    Calcium sulphate, at 25?? C., is two-thirds as soluble in dilute (o.i mol per liter) and twice as soluble in concentrated (3 mois per liter) ammonium sulphate solution as in water. The specific electric conductivity of concentrated ammonium sulphate solutions is lessened by saturating with calcium sulphate. Assuming that dissociation of ammonium sulphate takes place into 2NH4?? and SO4" and of calcium sulphate into Ca and SO4" only, and that the conductivity is a measure of such dissociation, the solubility of calcium sulphate in dilute ammonium sulphate solutions is greater than required by the mass-law. The conductivity of the dilute mixtures may be accurately calculated by means of Arrhenius' principle of isohydric solutions. In the data obtained in these calculations, the concentration of non-dissociated calcium sulphate decreases with increasing ammonium sulphate. The work as a whole is additional evidence of the fact that we are not yet in possession of all the factors necessary for reconciling the mass-law to the behavior of electrolytes. The measurements above described were made in the chemical laboratory of the University of Michigan.

  3. Calcium Carbonate

    MedlinePlus

    ... Maalox® (as a combination product containing Calcium Carbonate, Simethicone) ... Relief (as a combination product containing Calcium Carbonate, Simethicone) ... Plus (as a combination product containing Calcium Carbonate, Simethicone)

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

    PubMed Central

    Kinsey, William H.

    2012-01-01

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

  5. Impact of calcium signaling during infection of Neisseria meningitidis to human brain microvascular endothelial cells.

    PubMed

    Asmat, Tauseef M; Tenenbaum, Tobias; Jonsson, Ann-Beth; Schwerk, Christian; Schroten, Horst

    2014-01-01

    The pili and outer membrane proteins of Neisseria meningitidis (meningococci) facilitate bacterial adhesion and invasion into host cells. In this context expression of meningococcal PilC1 protein has been reported to play a crucial role. Intracellular calcium mobilization has been implicated as an important signaling event during internalization of several bacterial pathogens. Here we employed time lapse calcium-imaging and demonstrated that PilC1 of meningococci triggered a significant increase in cytoplasmic calcium in human brain microvascular endothelial cells, whereas PilC1-deficient meningococci could not initiate this signaling process. The increase in cytosolic calcium in response to PilC1-expressing meningococci was due to efflux of calcium from host intracellular stores as demonstrated by using 2-APB, which inhibits the release of calcium from the endoplasmic reticulum. Moreover, pre-treatment of host cells with U73122 (phospholipase C inhibitor) abolished the cytosolic calcium increase caused by PilC1-expressing meningococci demonstrating that active phospholipase C (PLC) is required to induce calcium transients in host cells. Furthermore, the role of cytosolic calcium on meningococcal adherence and internalization was documented by gentamicin protection assay and double immunofluorescence (DIF) staining. Results indicated that chelation of intracellular calcium by using BAPTA-AM significantly impaired PilC1-mediated meningococcal adherence to and invasion into host endothelial cells. However, buffering of extracellular calcium by BAPTA or EGTA demonstrated no significant effect on meningococcal adherence to and invasion into host cells. Taken together, these results indicate that meningococci induce calcium release from intracellular stores of host endothelial cells via PilC1 and cytoplasmic calcium concentrations play a critical role during PilC1 mediated meningococcal adherence to and subsequent invasion into host endothelial cells.

  6. Quantification of alginate by aggregation induced by calcium ions and fluorescent polycations.

    PubMed

    Zheng, Hewen; Korendovych, Ivan V; Luk, Yan-Yeung

    2016-01-01

    For quantification of polysaccharides, including heparins and alginates, the commonly used carbazole assay involves hydrolysis of the polysaccharide to form a mixture of UV-active dye conjugate products. Here, we describe two efficient detection and quantification methods that make use of the negative charges of the alginate polymer and do not involve degradation of the targeted polysaccharide. The first method utilizes calcium ions to induce formation of hydrogel-like aggregates with alginate polymer; the aggregates can be quantified readily by staining with a crystal violet dye. This method does not require purification of alginate from the culture medium and can measure the large amount of alginate that is produced by a mucoid Pseudomonas aeruginosa culture. The second method employs polycations tethering a fluorescent dye to form suspension aggregates with the alginate polyanion. Encasing the fluorescent dye in the aggregates provides an increased scattering intensity with a sensitivity comparable to that of the conventional carbazole assay. Both approaches provide efficient methods for monitoring alginate production by mucoid P. aeruginosa. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Seizure activity results in calcium- and mitochondria-independent ROS production via NADPH and xanthine oxidase activation

    PubMed Central

    Kovac, S; Domijan, A-M; Walker, M C; Abramov, A Y

    2014-01-01

    Seizure activity has been proposed to result in the generation of reactive oxygen species (ROS), which then contribute to seizure-induced neuronal damage and eventually cell death. Although the mechanisms of seizure-induced ROS generation are unclear, mitochondria and cellular calcium overload have been proposed to have a crucial role. We aim to determine the sources of seizure-induced ROS and their contribution to seizure-induced cell death. Using live cell imaging techniques in glioneuronal cultures, we show that prolonged seizure-like activity increases ROS production in an NMDA receptor-dependent manner. Unexpectedly, however, mitochondria did not contribute to ROS production during seizure-like activity. ROS were generated primarily by NADPH oxidase and later by xanthine oxidase (XO) activity in a calcium-independent manner. This calcium-independent neuronal ROS production was accompanied by an increase in intracellular [Na+] through NMDA receptor activation. Inhibition of NADPH or XO markedly reduced seizure-like activity-induced neuronal apoptosis. These findings demonstrate a critical role for ROS in seizure-induced neuronal cell death and identify novel therapeutic targets. PMID:25275601

  8. Risk of calcium oxalate nephrolithiasis in postmenopausal women supplemented with calcium or combined calcium and estrogen.

    PubMed

    Domrongkitchaiporn, Somnuek; Ongphiphadhanakul, Boonsong; Stitchantrakul, Wasana; Chansirikarn, Sirinthorn; Puavilai, Gobchai; Rajatanavin, Rajata

    2002-02-26

    Recent studies showed that postmenopausal women lost less bone mass when supplemented with calcium or estrogen therapy. However, the safety of the treatments in terms of the risk of calcium oxalate stone formation is unknown. We therefore conducted this study to determine the alteration in calcium oxalate supersaturation after calcium supplement or after combined calcium and estrogen therapy in postmenopausal osteoporotic women. Fifty-six postmenopausal women were enrolled in this study. All subjects were more than 10 years postmenopausal with vertebral or femoral osteoporosis by bone mineral density criteria. They were randomly allocated to receive either 625 mg of calcium carbonate (250 mg of elemental calcium) at the end of a meal three times a day (group A, n=26) or calcium carbonate in the same manner plus 0.625 mg/day of conjugated equine estrogen and 5 mg medrogestone acetate from day 1-12 each month (group B, n=30). The age (mean +/- S.E.M.) was 66.3 +/- 1.2 and 65.1 +/- 1.1 years, weight 54.1 +/- 1.2 and 55.3 +/- 2.1 kg, in group A and group B, respectively. Urine specimens (24-h) were collected at baseline and 3 months after treatment for the determination of calcium oxalate saturation by using Tiselius's index (AP(CaOx)) and calcium/citrate ratio. After 3 months of treatment, there was no significant alteration from baseline for urinary excretion of calcium, citrate and oxalate. Urinary phosphate excretion was significantly reduced (6.3 +/- 0.7 vs. 5.1 +/- 0.7 mmol/day for group A and 8.2 +/- 0.9 vs. 5.8 +/- 0.7 mmol/day for group B, P<0.05), whereas net alkaline absorption was significantly elevated (10.1 +/- 3.6 vs. 20.1 +/- 4.4 meq/day for group A and 4.8 +/- 3.2 vs. 19.9 +/- 3.6 meq/day for group B, P<0.05). Calcium/citrate ratio and AP(CaOx) determined at baseline were not different from the corresponding values after treatment in both groups; calcium/citrate: 10.1 +/- 3.1 vs. 10.1 +/- 2.5 for group A and 9.3 +/- 1.8 vs. 11.9 +/- 2.5 for group B and

  9. Synthetic peptides corresponding to human follicle-stimulating hormone (hFSH)-beta-(1-15) and hFSH-beta-(51-65) induce uptake of 45Ca++ by liposomes: evidence for calcium-conducting transmembrane channel formation

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

    Grasso, P.; Santa-Coloma, T.A.; Reichert, L.E. Jr.

    1991-06-01

    We have previously described FSH receptor-mediated influx of 45Ca++ in cultured Sertoli cells from immature rats and receptor-enriched proteoliposomes via activation of voltage-sensitive and voltage-independent calcium channels. We have further shown that this effect of FSH does not require cholera toxin- or pertussis toxin-sensitive guanine nucleotide binding protein or activation of adenylate cyclase. In the present study, we have identified regions of human FSH-beta-subunit which appear to be involved in mediating calcium influx. We screened 11 overlapping peptide amides representing the entire primary structure of hFSH-beta-subunit for their effects on 45Ca++ flux in FSH receptor-enriched proteoliposomes. hFSH-beta-(1-15) and hFSH-beta-(51-65) inducedmore » uptake of 45Ca++ in a concentration-related manner. This effect of hFSH-beta-(1-15) and hFSH-beta-(51-65) was also observed in liposomes lacking incorporated FSH receptor. Reducing membrane fluidity by incubating liposomes (containing no receptor) with hFSH-beta-(1-15) or hFSH-beta-(51-65) at temperatures lower than the transition temperatures of their constituent phospholipids resulted in no significant (P greater than 0.05) difference in 45Ca++ uptake. The effectiveness of the calcium ionophore A23187, however, was abolished. Ruthenium red, a voltage-independent calcium channel antagonist, was able to completely block uptake of 45Ca++ induced by hFSH-beta-(1-15) and hFSH-beta-(51-65) whereas nifedipine, a calcium channel blocker specific for L-type voltage-sensitive calcium channels, was without effect. These results suggest that in addition to its effect on voltage-sensitive calcium channel activity, interaction of FSH with its receptor may induce formation of transmembrane aqueous channels which also facilitate influx of extracellular calcium.« less

  10. RGDC Peptide-Induced Biomimetic Calcium Phosphate Coating Formed on AZ31 Magnesium Alloy

    PubMed Central

    Cao, Lin; Wang, Lina; Fan, Lingying; Xiao, Wenjun; Lin, Bingpeng; Xu, Yimeng; Liang, Jun; Cao, Baocheng

    2017-01-01

    Magnesium alloys as biodegradable metal implants have received a lot of interest in biomedical applications. However, magnesium alloys have extremely high corrosion rates a in physiological environment, which have limited their application in the orthopedic field. In this study, calcium phosphate compounds (Ca–P) coating was prepared by arginine–glycine–aspartic acid–cysteine (RGDC) peptide-induced mineralization in 1.5 simulated body fluid (SBF) to improve the corrosion resistance and biocompatibility of the AZ31 magnesium alloys. The adhesion of Ca–P coating to the AZ31 substrates was evaluated by a scratch test. Corrosion resistance and cytocompatibility of the Ca–P coating were investigated. The results showed that the RGDC could effectively promote the nucleation and crystallization of the Ca–P coating and the Ca–P coating had poor adhesion to the AZ31 substrates. The corrosion resistance and biocompatibility of the biomimetic Ca–P coating Mg alloys were greatly improved compared with that of the uncoated sample. PMID:28772717

  11. Role of calcium in the regulation of theca cell androstenedione production in the domestic hen.

    PubMed

    Levorse, J M; Tilly, J L; Johnson, A L

    1991-05-01

    Theca cells were collected from the second largest preovulatory follicle. Chelation of extracellular calcium with EGTA attenuated LH (10 ng)-induced androstenedione production by theca cells, and this effect was more pronounced in calcium-deficient than in calcium-replete incubation medium. Incubation of theca cells with steroidogenic agonists in the presence of the calcium channel blocker verapamil (100 microM) suppressed androstenedione production stimulated by LH (a 57% decrease), the adenylate cyclase activator forskolin (a 59% decrease) and the cyclic adenosine monophosphate (cAMP) analog 8-bromo-cAMP (a 61% decrease). Furthermore, 3,4,5-trimethoxybenzoic acid 8-(diethylamino)octyl ester (TMB-8), a putative inhibitor of intracellular calcium mobilization, suppressed LH-induced androstenedione production in a dose-dependent fashion. The calmodulin inhibitors trifluoperazine (100 microM) and R24571 (50 microM) inhibited androstenedione production stimulated by hormonal (LH) and non-hormonal (forskolin, 8-bromo-cAMP) agonists (decreases ranging from 76 to 98%). While increasing the intracellular calcium ion concentrations with the calcium ionophore A23187 did not affect basal concentrations of androstenedione, treatment of LH-stimulated cells with the ionophore caused dose-dependent inhibition of androstenedione production; these effects were enhanced by coincubation with phorbol 12-myristate 13-acetate (a known activator of protein kinase C). We conclude that the mobilization of calcium is critical for agonist-stimulated steroidogenesis in hen theca cells, apparently requiring the interaction of calcium with its binding protein, calmodulin. Furthermore, increased cytosolic calcium concentrations may be involved in the suppression of androstenedione production, possibly as a result of an interaction with protein kinase C.

  12. Modulation of the activity of midbrain central gray substance neurons by calcium channel agonists and antagonists in vitro.

    PubMed

    Yakhnitsa, V A; Pilyavskii, A I; Limansky, Y P; Bulgakova, N V

    1996-01-01

    Changes in the background impulse activity of midbrain central gray substance neurons have been studied on slice preparations from the rat midbrain upon application of calcium-free solution, an activator of calcium channels, BAY-K 8644 (10 nM), organic (verapamil, 40 microM; D600, 10 microM; nifedipine, 1-10 microM; amiloride, 1 microM) and inorganic (Co2+, 1.5 mM) calcium channel blockers. Besides BAY-K 8644, all the substances inhibited most of the neurons studied. Verapamil, BAY-K 8644 and Co2+ also revealed facilitatory effects. Facilitatory action of BAY-K was most effective in silent neurons and in those previously inhibited by amiloride. Latent period values of inhibition in calcium-free solution and upon application of organic and inorganic blockers have the following sequence: D600 > amiloride > verapamil > Co2+ > nifedipine > calcium-free solution. Maximum rise time had the following order: amiloride > D600 > nifedipine > verapamil > Co2+ > calcium-free solution. Complete suppression of the neuronal activity induced by amiloride lasted twice as long as that induced by calcium-free solution, Co2+ and nifedipine, and six times as long as verapamil-induced suppression. Preliminary application of calcium channel blockers reduced facilitatory and increased inhibitory effects of serotonin and substance P. Data obtained are discussed with the supposition in mind that inhibition of the function of calcium channels in central gray substance neurons could be one of the mechanisms underlying the analgesic effect of a series of neurotropic agents after their introduction into this structure.

  13. Normocalcemia is maintained in mice under conditions of calcium malabsorption by vitamin D–induced inhibition of bone mineralization

    PubMed Central

    Lieben, Liesbet; Masuyama, Ritsuko; Torrekens, Sophie; Van Looveren, Riet; Schrooten, Jan; Baatsen, Pieter; Lafage-Proust, Marie-Hélène; Dresselaers, Tom; Feng, Jian Q.; Bonewald, Lynda F.; Meyer, Mark B.; Pike, J. Wesley; Bouillon, Roger; Carmeliet, Geert

    2012-01-01

    Serum calcium levels are tightly controlled by an integrated hormone-controlled system that involves active vitamin D [1,25(OH)2D], which can elicit calcium mobilization from bone when intestinal calcium absorption is decreased. The skeletal adaptations, however, are still poorly characterized. To gain insight into these issues, we analyzed the consequences of specific vitamin D receptor (Vdr) inactivation in the intestine and in mature osteoblasts on calcium and bone homeostasis. We report here that decreased intestinal calcium absorption in intestine-specific Vdr knockout mice resulted in severely reduced skeletal calcium levels so as to ensure normal levels of calcium in the serum. Furthermore, increased 1,25(OH)2D levels not only stimulated bone turnover, leading to osteopenia, but also suppressed bone matrix mineralization. This resulted in extensive hyperosteoidosis, also surrounding the osteocytes, and hypomineralization of the entire bone cortex, which may have contributed to the increase in bone fractures. Mechanistically, osteoblastic VDR signaling suppressed calcium incorporation in bone by directly stimulating the transcription of genes encoding mineralization inhibitors. Ablation of skeletal Vdr signaling precluded this calcium transfer from bone to serum, leading to better preservation of bone mass and mineralization. These findings indicate that in mice, maintaining normocalcemia has priority over skeletal integrity, and that to minimize skeletal calcium storage, 1,25(OH)2D not only increases calcium release from bone, but also inhibits calcium incorporation in bone. PMID:22523068

  14. CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING IN CENTER, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING IN CENTER, CALCIUM CHLORIDE STORAGE BUILDING ON RIGHT WITH SA (SODA ASH) BUILDING IN RIGHT BACKGROUND. - Solvay Process Company, Calcium Chloride Plant, Between Willis & Milton Avenues, Solvay, Onondaga County, NY

  15. Individual and family correlates of calcium-rich food intake among parents of early adolescent children.

    PubMed

    Reicks, Marla; Ballejos, Miriam Edlefsen; Goodell, L Suzanne; Gunther, Carolyn; Richards, Rickelle; Wong, Siew Sun; Auld, Garry; Boushey, Carol J; Bruhn, Christine; Cluskey, Mary; Misner, Scottie; Olson, Beth; Zaghloul, Sahar

    2011-03-01

    Most adults do not meet calcium intake recommendations. Little is known about how individual and family factors, including parenting practices that influence early adolescents' intake of calcium-rich foods, affect calcium intake of parents. This information could inform the development of effective nutrition education programs. To identify individual and family factors associated with intake of calcium-rich foods among parents of early adolescents (aged 10 to 13 years). A cross-sectional survey was used with 14 scales to assess attitudes/preferences and parenting practices regarding calcium-rich foods and a calcium-specific food frequency questionnaire (2006-2007). A convenience sample of self-reporting non-Hispanic white, Hispanic, and Asian (n=661) parents was recruited in nine states. Parents were the primary meal planner/preparer and completed questionnaires in homes or community settings. Predictors of calcium intake from three food groupings-all food sources, dairy foods, and milk. Multivariate regression analyses identified demographic, attitude/preference, and behavioral factors associated with calcium intake. Most respondents were women (∼90%) and 38% had a college degree. Education was positively associated with calcium intake from all three food groupings, whereas having an Asian spouse compared to a non-Hispanic white spouse was negatively associated with calcium intake only from all food sources and from dairy foods. Expectations for and encouragement of healthy beverage intake for early adolescents were positively associated with calcium intake from dairy foods and milk, respectively. Parental concern regarding adequacy of intake was negatively associated, whereas perception of health benefits from calcium-rich foods was positively associated with calcium intake from all food sources and from dairy foods. Between 20% and 32% of the variance in calcium intake from all food groupings was explained in these models. Individual factors and positive

  16. Effects of calcium and vitamin D3 on transforming growth factors in rectal mucosa of sporadic colorectal adenoma patients: a randomized controlled trial.

    PubMed

    Tu, Huakang; Flanders, W Dana; Ahearn, Thomas U; Daniel, Carrie R; Gonzalez-Feliciano, Amparo G; Long, Qi; Rutherford, Robin E; Bostick, Roberd M

    2015-04-01

    Transforming growth factor alpha (TGFα) and TGFβ1 are growth-promoting and -inhibiting autocrine/paracrine growth factors, respectively, that may (1) affect risk for colorectal cancer and (2) be modifiable by anti-proliferative exposures. The effects of supplemental calcium and vitamin D3 on these two markers in the normal-appearing colorectal mucosa in humans are unknown. We conducted a pilot, randomized, double-blind, placebo-controlled, 2 × 2 factorial clinical trial (n = 92; 23/treatment group) of calcium 2 g and/or vitamin D3 800 IU/d versus placebo over 6 mo. TGFα and TGFβ1 expression was measured in biopsies of normal-appearing rectal mucosa using automated immunohistochemistry and quantitative image analysis at baseline and 6-mo follow-up. In the calcium, vitamin D3 , and calcium plus vitamin D3 groups relative to the placebo group (1) the mean overall expression of TGFβ1 increased by 14% (P= 0.25), 19% (P = 0.17), and 22% (P = 0.09); (2) the ratio of TGFα expression in the upper 40% (differentiation zone) to that in the lower 60 (proliferation zone) of the crypts decreased by 34% (P = 0.11), 31% (P = 0.22), and 26% (P = 0.33); and (3) the TGFα/TGFβ1 ratio in the upper 40% of the crypts decreased by 28% (P = 0.09), 14% (P = 0.41), and 22% (P = 0.24), respectively. These preliminary results, although not statistically significant, suggest that supplemental calcium and vitamin D3 may increase TGFβ1 expression and shift TGFα expression downward from the differentiation to the proliferation zone in the crypts in the normal-appearing colorectal mucosa of sporadic colorectal adenoma patients, and support further investigation in a larger clinical trial. © 2013 Wiley Periodicals, Inc.

  17. Properties of calcium silicate-monobasic calcium phosphate materials for endodontics containing tantalum pentoxide and zirconium oxide.

    PubMed

    Zamparini, Fausto; Siboni, Francesco; Prati, Carlo; Taddei, Paola; Gandolfi, Maria Giovanna

    2018-05-08

    The aim of the study was to evaluate chemical-physical properties and apatite-forming ability of three premixed calcium silicate materials containing monobasic calcium phosphate (CaH 4 P 2 O 8 ) bioceramic, tantalum pentoxide and zirconium oxide, recently marketed for endodontics (TotalFill BC-Sealer, BC-RRM-Paste, BC-RRM-Putty). Microchemical and micromorphological analyses, radiopacity, initial and final setting times, calcium release and alkalising activity were tested. The nucleation of calcium phosphates (CaPs) and/or apatite after 28 days ageing was evaluated by ESEM-EDX and micro-Raman spectroscopy. BC-Sealer and BC-RRM-Paste showed similar initial (23 h), prolonged final (52 h) setting times and good radiopacity (> 7 mm Al); BC-RRM-Putty showed fast initial (2 h) and final setting times (27 h) and excellent radiopacity (> 9 mm Al). All materials induced a marked alkalisation (pH 11-12) up to 28 days and showed the release of calcium ions throughout the entire test period (cumulative calcium release 641-806 ppm). After 28 days ageing, a well-distributed mineral layer was present on all samples surface; EDX demonstrated relevant calcium and phosphorous peaks. B-type carbonated apatite and calcite deposits were identified by micro-Raman spectroscopy on all the 28-day-aged samples; the deposit thickness was higher on BC-RRM-Paste and BC-RRM-Putty, in agreement with calcium release data. These materials met the required chemical and physical standards and released biologically relevant ions. The CaSi-CaH 4 P 2 O 8 system present in the materials provided Ca and OH ions release with marked abilities to nucleate a layer of B-type carbonated apatite favoured/accelerated by the bioceramic presence. The ability to nucleate apatite may lead many clinical advantages: In orthograde endodontics, it may improve the sealing ability by the deposition of CaPs at the material-root dentine interface, and in endodontic surgery, it could promote bone and

  18. Capsaicin sensitizes TRAIL-induced apoptosis through Sp1-mediated DR5 up-regulation: Involvement of Ca{sup 2+} influx

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

    Moon, Dong-Oh; Kang, Chang-Hee; Kang, Sang-Hyuck

    2012-02-15

    Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in various malignant cells, several cancers including human hepatocellular carcinoma (HCC) exhibit potent resistance to TRAIL-induced cell death. The aim of this study is to evaluate the anti-cancer potential of capsaicin in TRAIL-induced cancer cell death. As indicated by assays that measure phosphatidylserine exposure, mitochondrial activity and activation of caspases, capsaicin potentiated TRAIL-resistant cells to lead to cell death. In addition, we found that capsaicin induces the cell surface expression of TRAIL receptor DR5, but not DR4 through the activation Sp1 on its promoter region. Furthermore, we investigated that capsaicin-induced DR5more » expression and apoptosis are inhibited by calcium chelator or inhibitors for calmodulin-dependent protein kinase. Taken together, our data suggest that capsaicin sensitizes TRAIL-mediated HCC cell apoptosis by DR5 up-regulation via calcium influx-dependent Sp1 activation. Highlights: ► Capsaicin sensitizes TRAIL-induced apoptosis through activation of caspases. ► Capsaicin induces expression of DR5 through Sp1 activation. ► Capsaicin activates calcium signaling pathway.« less

  19. Nitric oxide-activated calcium/calmodulin-dependent protein kinase regulates the abscisic acid-induced antioxidant defence in maize

    PubMed Central

    Zhang, Aying; Jiang, Mingyi

    2012-01-01

    Nitric oxide (NO), hydrogen peroxide (H2O2), and calcium (Ca2+)/calmodulin (CaM) are all required for abscisic acid (ABA)-induced antioxidant defence. Ca2+/CaM-dependent protein kinase (CCaMK) is a strong candidate for the decoder of Ca2+ signals. However, whether CCaMK is involved in ABA-induced antioxidant defence is unknown. The results of the present study show that exogenous and endogenous ABA induced increases in the activity of ZmCCaMK and the expression of ZmCCaMK in leaves of maize. Subcellular localization analysis showed that ZmCCaMK is located in the nucleus, the cytoplasm, and the plasma membrane. The transient expression of ZmCCaMK and the RNA interference (RNAi) silencing of ZmCCaMK analysis in maize protoplasts revealed that ZmCCaMK is required for ABA-induced antioxidant defence. Moreover, treatment with the NO donor sodium nitroprusside (SNP) induced the activation of ZmCCaMK and the expression of ZmCCaMK. Pre-treatments with an NO scavenger and inhibitor blocked the ABA-induced increases in the activity and the transcript level of ZmCCaMK. Conversely, RNAi silencing of ZmCCaMK in maize protoplasts did not affect the ABA-induced NO production, which was further confirmed using a mutant of OsCCaMK, the homologous gene of ZmCCaMK in rice. Moreover, H2O2 was also required for the ABA activation of ZmCCaMK, and pre-treatments with an NO scavenger and inhibitor inhibited the H2O2-induced increase in the activity of ZmCCaMK. Taken together, the data clearly suggest that ZmCCaMK is required for ABA-induced antioxidant defence, and H2O2-dependent NO production plays an important role in the ABA-induced activation of ZmCCaMK. PMID:22865912

  20. Plasma oxalic acid and calcium levels in oxalate poisoning

    PubMed Central

    Zarembski, P. M.; Hodgkinson, A.

    1967-01-01

    Observations are reported on five cases of suicide or attempted suicide by poisoning with oxalic acid or ethylene glycol. Elevated oxalic acid levels were observed in the plasma, stomach contents, and a number of tissues. Raised oxalic acid levels in plasma were associated with reduced total and ultrafilterable calcium levels. It is suggested that the reduction in plasma total calcium level is due mainly to the deposition of calcium oxalate in the soft tissues, but inhibition of the parathyroid glands may be a contributory factor. Microscopic examination of various tissues indicated that oxalic acid is deposited in the tissues in two forms: (1) crystalline calcium oxalate dihydrate in the kidney and (2) a non-crystalline complex of calcium oxalate and lipid in liver and other tissues. PMID:5602563

  1. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.330 Calcium pantothenate, calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may...

  2. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.330 Calcium pantothenate, calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may...

  3. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.330 Calcium pantothenate, calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may...

  4. CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING ON LEFT, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING ON LEFT, CALCIUM CHLORIDE STORAGE BUILDING ON RIGHT OF CENTER WITH TOP OF SA (SODA ASH) BUILDING IN RIGHT BACKGROUND. - Solvay Process Company, Calcium Chloride Plant, Between Willis & Milton Avenues, Solvay, Onondaga County, NY

  5. Increased calcium deposits and decreased Ca2+-ATPase in right ventricular myocardium of ascitic broiler chickens.

    PubMed

    Li, K; Qiao, J; Zhao, L; Dong, S; Ou, D; Wang, J; Wang, H; Xu, T

    2006-11-01

    Right ventricular hypertrophy and failure is an important step in the development of ascites syndrome (AS) in broiler chickens. Cytoplasmic calcium concentration is a major regulator of cardiac contractile function and various physiological processes in cardiac muscle cells. The purpose of this study was to measure the right ventricular pressure and investigate the precise ultrastructural location of Ca(2+) and Ca(2+)-ATPase in the right ventricular myocardium of chickens with AS induced by low ambient temperature. The results showed that the right ventricular diastolic pressure of ascitic broilers was significantly higher than that of control broilers (P < 0.01), and the maximum change ratio of right intraventricular pressure (RV +/- dp/dt(max)) of ascitic broilers was significantly lower than that of the controls (P < 0.01). Extensively increased calcium deposits were observed in the right ventricular myocardium of ascitic broilers, whereas in the age-matched control broilers, calcium deposits were much less. The Ca(2+)-ATPase reactive products were obviously found on the sarcoplasmic reticulum and mitochondrial membrane of the control right ventricular myocardium, but rarely observed in the ascitic broilers. The data suggest that in ascitic broilers there is the right ventricular diastolic dysfunction, in which the overload of intracellular calcium and the decreased Ca(2+)-ATPase activity might be the important factors.

  6. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... SERVICES (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.330 Calcium pantothenate, calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may be safely used in foods for special...

  7. Calcium regulates FGF-23 expression in bone.

    PubMed

    David, Valentin; Dai, Bing; Martin, Aline; Huang, Jinsong; Han, Xiaobin; Quarles, L Darryl

    2013-12-01

    Calcium has recently been shown to regulate fibroblast growth factor 23 (FGF-23), a bone-derived phosphate and vitamin D-regulating hormone. To better understand the regulation of FGF-23 by calcium, phosphorus, 1,25 dihydroxyvitamin D3 [1,25(OH)2D], and PTH, we examined FGF-23 expression under basal conditions and in response to PTH, doxercalciferol, or high-calcium diet treatment in Gcm2(-/-) and Cyp27b1(-/-) mutant mice. Gcm2(-/-) mice exhibited low serum PTH and 1,25(OH)2D concentrations, hypocalcemia, and hyperphosphatemia, whereas Cyp27b1(-/-) mice had high PTH, undetectable 1,25(OH)2D, hypocalcemia, and hypophosphatemia. Serum FGF-23 levels were decreased in both mutant models. Doxercalciferol administration increased serum FGF-23 levels in both mutant models. PTH administration to Gcm2(-/-) mice also increased serum FGF-23 levels, in association with an increase in both 1,25(OH)2D and calcium concentrations. Multiple regression analysis of pooled data indicated that changes in FGF-23 were positively correlated with serum calcium and 1,25(OH)2D but not related to changes in serum phosphate concentrations. A high-calcium diet also increased serum FGF-23 concentrations in Cyp27b1(-/-) mice in the absence of 1,25(OH)2D and in Gcm2(-/-) mice with low PTH. The addition of calcium to the culture media also stimulated FGF-23 message expression in MC3T3-E1 osteoblasts. In addition, FGF-23 promoter activity in cultured osteoblasts was inhibited by the L-calcium-channel inhibitor nifedipine and stimulated by calcium ionophores. The effects of chronic low calcium to prevent 1,25(OH)2D and PTH stimulation of FGF-23 in these mutant mouse models suggest that suppression of FGF-23 plays an important physiological adaptive response to hypocalcemia.

  8. Neuroprotective effect of gadolinium: a stretch-activated calcium channel blocker in mouse model of ischemia-reperfusion injury.

    PubMed

    Gulati, Puja; Muthuraman, Arunachalam; Jaggi, Amteshwar S; Singh, Nirmal

    2013-03-01

    The present study was designed to investigate the potential of gadolinium, a stretch-activated calcium channel blocker in ischemic reperfusion (I/R)-induced brain injury in mice. Bilateral carotid artery occlusion of 12 min followed by reperfusion for 24 h was given to induce cerebral injury in male Swiss mice. Cerebral infarct size was measured using triphenyltetrazolium chloride staining. Memory was assessed using Morris water maze test and motor incoordination was evaluated using rota-rod, lateral push, and inclined beam walking tests. In addition, total calcium, thiobarbituric acid reactive substance (TBARS), reduced glutathione (GSH), and acetylcholinesterase (AChE) activity were also estimated in brain tissue. I/R injury produced a significant increase in cerebral infarct size. A significant loss of memory along with impairment of motor performance was also noted. Furthermore, I/R injury also produced a significant increase in levels of TBARS, total calcium, AChE activity, and a decrease in GSH levels. Pretreatment of gadolinium significantly attenuated I/R-induced infarct size, behavioral and biochemical changes. On the basis of the present findings, we can suggest that opening of stretch-activated calcium channel may play a critical role in ischemic reperfusion-induced brain injury and that gadolinium has neuroprotective potential in I/R-induced injury.

  9. Calcium responses to synaptically activated bursts of action potentials and their synapse-independent replay in cultured networks of hippocampal neurons.

    PubMed

    Bengtson, C Peter; Kaiser, Martin; Obermayer, Joshua; Bading, Hilmar

    2013-07-01

    Both synaptic N-methyl-d-aspartate (NMDA) receptors and voltage-operated calcium channels (VOCCs) have been shown to be critical for nuclear calcium signals associated with transcriptional responses to bursts of synaptic input. However the direct contribution to nuclear calcium signals from calcium influx through NMDA receptors and VOCCs has been obscured by their concurrent roles in action potential generation and synaptic transmission. Here we compare calcium responses to synaptically induced bursts of action potentials with identical bursts devoid of any synaptic contribution generated using the pre-recorded burst as the voltage clamp command input to replay the burst in the presence of blockers of action potentials or ionotropic glutamate receptors. Synapse independent replays of bursts produced nuclear calcium responses with amplitudes around 70% of their original synaptically generated signals and were abolished by the L-type VOCC blocker, verapamil. These results identify a major direct source of nuclear calcium from local L-type VOCCs whose activation is boosted by NMDA receptor dependent depolarization. The residual component of synaptically induced nuclear calcium signals which was both VOCC independent and NMDA receptor dependent showed delayed kinetics consistent with a more distal source such as synaptic NMDA receptors or internal stores. The dual requirement of NMDA receptors and L-type VOCCs for synaptic activity-induced nuclear calcium dependent transcriptional responses most likely reflects a direct somatic calcium influx from VOCCs whose activation is amplified by synaptic NMDA receptor-mediated depolarization and whose calcium signal is boosted by a delayed input from distal calcium sources mostly likely entry through NMDA receptors and release from internal stores. This article is part of a Special Issue entitled: 12th European Symposium on Calcium. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Calcium and nitrogen balance, experiment M007

    NASA Technical Reports Server (NTRS)

    Whedon, G. D.; Lutwak, L.; Neuman, W. F.; Lachance, P. A.

    1971-01-01

    The collection of data on the response of the skeletal and muscular systems to 14-day space flights was evaluated for loss of calcium, nitrogen, and other metabolically related elements. Considerable interindividual variability was demonstrated in all experimental factors that were measured. Calcium balance became less positive and urinary phosphate excretion increased substantially in flight despite a reduction in phosphate intake. Patterns of excretion of magnesium, sodium, potassium, and chloride were different for each subject, and, in part, could be correlated with changes in adrenocortical steroid production. The principal hormonal change was a striking decrease during flight in the urinary excretion of 17-hydroxycortocosteroids. Dermal losses of calcium, magnesium, sulfate, and phosphate were insignificant during all three phases.

  11. Ryanodine receptor gating controls generation of diastolic calcium waves in cardiac myocytes

    PubMed Central

    Petrovič, Pavol; Valent, Ivan; Cocherová, Elena; Pavelková, Jana

    2015-01-01

    The role of cardiac ryanodine receptor (RyR) gating in the initiation and propagation of calcium waves was investigated using a mathematical model comprising a stochastic description of RyR gating and a deterministic description of calcium diffusion and sequestration. We used a one-dimensional array of equidistantly spaced RyR clusters, representing the confocal scanning line, to simulate the formation of calcium sparks. Our model provided an excellent description of the calcium dependence of the frequency of diastolic calcium sparks and of the increased tendency for the production of calcium waves after a decrease in cytosolic calcium buffering. We developed a hypothesis relating changes in the propensity to form calcium waves to changes of RyR gating and tested it by simulation. With a realistic RyR gating model, increased ability of RyR to be activated by Ca2+ strongly increased the propensity for generation of calcium waves at low (0.05–0.1-µM) calcium concentrations but only slightly at high (0.2–0.4-µM) calcium concentrations. Changes in RyR gating altered calcium wave formation by changing the calcium sensitivity of spontaneous calcium spark activation and/or the average number of open RyRs in spontaneous calcium sparks. Gating changes that did not affect RyR activation by Ca2+ had only a weak effect on the propensity to form calcium waves, even if they strongly increased calcium spark frequency. Calcium waves induced by modulating the properties of the RyR activation site could be suppressed by inhibiting the spontaneous opening of the RyR. These data can explain the increased tendency for production of calcium waves under conditions when RyR gating is altered in cardiac diseases. PMID:26009544

  12. Comparative evaluation of different forms of calcium hydroxide in apexification.

    PubMed

    Ghosh, Subhankar; Mazumdar, Dibyendu; Ray, Pradip Kumar; Bhattacharya, Bhaswar

    2014-01-01

    One out of every two children sustains a dental injury most often between 8 and 10 years of age. Majority of these teeth subsequently become non-vital and most often with immature apex. Management of these teeth is an enormous challenge for lack of apical stop. Calcium hydroxide in various formulations has maximum literature support in favor of successful apexification or induced apical closure. The aim of the following study is to determine the efficacy of calcium hydroxide in a different formulation to induce apexification. The present study was undertaken on 51 children of 8-10 years of age (both sexes) at Dr. R Ahmed Dental College and Hospital from April 2006 to March 2007. All children had one or two maxillary permanent central incisor (s), non-vital and apices open. In all the cases, apexification was attempted with either calcium hydroxide mixed with sterile distilled water, or calcium hydroxide plus iodoform in methyl cellulose base, or calcium hydroxide plus iodoform in polysilicone oil base. The success of apexification was determined on the basis of clinical and radiographic criteria. In the pre-operative asymptomatic cases (72.55%), failure occurred in only 5.45% cases and pre-operative symptomatic cases failure rate was as high as 35.71%. Success rate was 94.6% in cases with narrow open apices, whereas 64.28% in wide open apices. In cases with pre-existing apical radiolucencies, successful apexification occurred in 63.63% and success rate was 92.5% in the cases without pre-existing apical radiolucencies. Average time consumed for apexification was minimum with calcium hydroxide plus iodoform in polysilicone oil base. The overall success rate observed to be 86.27%, which is in close proximity to the findings of most of the previous studies across the globe.

  13. Aluminum Citrate Prevents Renal Injury from Calcium Oxalate Crystal Deposition

    PubMed Central

    Besenhofer, Lauren M.; Cain, Marie C.; Dunning, Cody

    2012-01-01

    Calcium oxalate monohydrate crystals are responsible for the kidney injury associated with exposure to ethylene glycol or severe hyperoxaluria. Current treatment strategies target the formation of calcium oxalate but not its interaction with kidney tissue. Because aluminum citrate blocks calcium oxalate binding and toxicity in human kidney cells, it may provide a different therapeutic approach to calcium oxalate-induced injury. Here, we tested the effects of aluminum citrate and sodium citrate in a Wistar rat model of acute high-dose ethylene glycol exposure. Aluminum citrate, but not sodium citrate, attenuated increases in urea nitrogen, creatinine, and the ratio of kidney to body weight in ethylene glycol–treated rats. Compared with ethylene glycol alone, the addition of aluminum citrate significantly increased the urinary excretion of both crystalline calcium and crystalline oxalate and decreased the deposition of crystals in renal tissue. In vitro, aluminum citrate interacted directly with oxalate crystals to inhibit their uptake by proximal tubule cells. These results suggest that treating with aluminum citrate attenuates renal injury in rats with severe ethylene glycol toxicity, apparently by inhibiting calcium oxalate’s interaction with, and retention by, the kidney epithelium. PMID:23138489

  14. Hydrogen peroxide-induced DNA damage is independent of nuclear calcium but dependent on redox-active ions.

    PubMed Central

    Jornot, L; Petersen, H; Junod, A F

    1998-01-01

    In cells undergoing oxidative stress, DNA damage may result from attack by .OH radicals produced by the Fenton reaction, and/or by nucleases activated by nuclear calcium. In the present study, the participation of these two mechanisms was investigated in HeLa cells. Nuclear-targeted aequorin was used for selectively monitoring Ca2+ concentrations within the nuclei ([Ca2+]n), in conjunction with the cell-permeant calcium chelator bis-(o-aminophenoxy)ethane-N,N,N', N'-tetraacetic acid acetoxymethyl ester (BAPTA/AM), the lipid-soluble broad-spectrum metal chelator with low affinity for Ca2+ and Mg2+ N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), and the high-affinity iron/copper chelator 1, 10-phenanthroline (PHE). In Ca2+-containing medium, H2O2 induced extensive DNA strand breaks and an increase in [Ca2+]n that was almost identical to that observed in the cytosol ([Ca2+]c). In cells bathed in Ca2+-free/EGTA medium, in which the increases in [Ca2+]n and [Ca2+]c due to H2O2 were significantly reduced, similar levels of DNA fragmentation also occurred. In cells preloaded with BAPTA/AM or TPEN, the small increase of [Ca2+]n normally elicited by H2O2 in Ca2+-free medium was completely buffered, and DNA damage was largely prevented. On the other hand, pretreatment with PHE did not affect the calcium response in the nuclei, but completely prevented DNA strand breakage induced by H2O2. Re-addition of 100 microM CuSO4 and 100 microM FeSO4 to TPEN- and PHE-treated cells prior to H2O2 challenge reversed the effect of TPEN and PHE, whereas 1 mM was necessary to negate the effect of BAPTA/AM. The levels of DNA strand breakage observed, however, did not correlate with the amounts of 8-hydroxy 2'-deoxyguanosine (8-OHdG): H2O2 did not produce 8-OHdG, whereas PHE alone slightly increased 8-OHdG levels. CuSO4 and FeSO4 enhanced the effects of PHE, particularly in the presence of H2O2. Exposure of cells to a mixture of CuSO4/FeSO4 also resulted in a significant increase in

  15. Targeting Cellular Calcium Homeostasis to Prevent Cytokine-Mediated Beta Cell Death.

    PubMed

    Clark, Amy L; Kanekura, Kohsuke; Lavagnino, Zeno; Spears, Larry D; Abreu, Damien; Mahadevan, Jana; Yagi, Takuya; Semenkovich, Clay F; Piston, David W; Urano, Fumihiko

    2017-07-17

    Pro-inflammatory cytokines are important mediators of islet inflammation, leading to beta cell death in type 1 diabetes. Although alterations in both endoplasmic reticulum (ER) and cytosolic free calcium levels are known to play a role in cytokine-mediated beta cell death, there are currently no treatments targeting cellular calcium homeostasis to combat type 1 diabetes. Here we show that modulation of cellular calcium homeostasis can mitigate cytokine- and ER stress-mediated beta cell death. The calcium modulating compounds, dantrolene and sitagliptin, both prevent cytokine and ER stress-induced activation of the pro-apoptotic calcium-dependent enzyme, calpain, and partly suppress beta cell death in INS1E cells and human primary islets. These agents are also able to restore cytokine-mediated suppression of functional ER calcium release. In addition, sitagliptin preserves function of the ER calcium pump, sarco-endoplasmic reticulum Ca 2+ -ATPase (SERCA), and decreases levels of the pro-apoptotic protein thioredoxin-interacting protein (TXNIP). Supporting the role of TXNIP in cytokine-mediated cell death, knock down of TXNIP in INS1-E cells prevents cytokine-mediated beta cell death. Our findings demonstrate that modulation of dynamic cellular calcium homeostasis and TXNIP suppression present viable pharmacologic targets to prevent cytokine-mediated beta cell loss in diabetes.

  16. Calcium - urine

    MedlinePlus

    Urinary Ca+2; Kidney stones - calcium in urine; Renal calculi - calcium in your urine; Parathyroid - calcium in urine ... A 24-hour urine sample is most often needed: On day 1, urinate into the toilet when you wake up in the morning. ...

  17. Calcium/Vitamin D Supplementation and Coronary Artery Calcification

    PubMed Central

    Manson, JoAnn E.; Allison, Matthew A.; Carr, J. Jeffrey; Langer, Robert D.; Cochrane, Barbara B.; Hendrix, Susan L.; Hsia, Judith; Hunt, Julie R.; Lewis, Cora E.; Margolis, Karen L.; Robinson, Jennifer G.; Rodabough, Rebecca J.; Thomas, Asha M.

    2010-01-01

    Objectives Coronary artery calcified plaque is a marker for atheromatous plaque burden and predicts future risk of cardiovascular events. The relationship between calcium plus vitamin D supplementation and coronary artery calcium (CAC) has not been previously assessed in a randomized trial setting. We compared coronary artery calcium scores among women randomized to calcium/vitamin D supplementation versus placebo following trial completion. Methods In an ancillary substudy of women randomized to calcium carbonate (1000 mg of elemental calcium daily) plus vitamin D3 (400 IU daily) versus placebo, nested within the Women’s Health Initiative trial of estrogen among women with hysterectomy, we measured CAC with cardiac computed tomography in 754 women aged 50–59 years at randomization. Imaging for CAC was performed at 28 of 40 centers following a mean of 7 years of treatment and scans were read centrally. Coronary artery calcium scores were measured by a central reading center with masking to randomization assignments. Results Post-trial CAC measurements were similar in women randomized to calcium/vitamin D supplementation (calcium/D) and those receiving placebo. The mean CAC score was 91.6 for calcium/D and 100.5 for placebo (rank test p-value=0.74). After adjustment for coronary risk factors, multivariate odds ratios for increasing CAC score cutpoints (CAC >0, ≥10, and ≥100) for calcium/D vs placebo were 0.92 (95% confidence interval, 0.64–1.34), 1.29 (0.88–1.87), and 0.90 (0.56–1.44), respectively. Corresponding odds ratios among women with >50% adherence to study pills and for higher levels of CAC (>300), were similar. Conclusions Treatment with moderate doses of calcium plus vitamin D3 did not appear to alter coronary artery calcified plaque burden among postmenopausal women. PMID:20551849

  18. PeakCaller: an automated graphical interface for the quantification of intracellular calcium obtained by high-content screening.

    PubMed

    Artimovich, Elena; Jackson, Russell K; Kilander, Michaela B C; Lin, Yu-Chih; Nestor, Michael W

    2017-10-16

    Intracellular calcium is an important ion involved in the regulation and modulation of many neuronal functions. From regulating cell cycle and proliferation to initiating signaling cascades and regulating presynaptic neurotransmitter release, the concentration and timing of calcium activity governs the function and fate of neurons. Changes in calcium transients can be used in high-throughput screening applications as a basic measure of neuronal maturity, especially in developing or immature neuronal cultures derived from stem cells. Using human induced pluripotent stem cell derived neurons and dissociated mouse cortical neurons combined with the calcium indicator Fluo-4, we demonstrate that PeakCaller reduces type I and type II error in automated peak calling when compared to the oft-used PeakFinder algorithm under both basal and pharmacologically induced conditions. Here we describe PeakCaller, a novel MATLAB script and graphical user interface for the quantification of intracellular calcium transients in neuronal cultures. PeakCaller allows the user to set peak parameters and smoothing algorithms to best fit their data set. This new analysis script will allow for automation of calcium measurements and is a powerful software tool for researchers interested in high-throughput measurements of intracellular calcium.

  19. Soil-calcium depletion linked to acid rain and forest growth in the eastern United States

    USGS Publications Warehouse

    Lawrence, Gregory B.; Huntington, T.G.

    1999-01-01

    Since the discovery of acid rain in the 1970's, scientists have been concerned that deposition of acids could cause depletion of calcium in forest soils. Research in the 1980's showed that the amount of calcium in forest soils is controlled by several factors that are difficult to measure. Further research in the 1990's, including several studies by the U.S. Geological Survey, has shown that (1) calcium in forest soils has decreased at locations in the northeastern and southeastern U.S., and (2) acid rain and forest growth (uptake of calcium from the soil by roots) are both factors contributing to calcium depletion.

  20. Salicylic acid and calcium-induced protection of wheat against salinity.

    PubMed

    Al-Whaibi, Mohamed H; Siddiqui, Manzer H; Basalah, Mohammed O

    2012-07-01

    Soil salinity is one of the important environmental factors that produce serious agricultural problems. The objective of the present study was to determine the interactive effect of salicylic acid (SA) and calcium (Ca) on plant growth, photosynthetic pigments, proline (Pro) concentration, carbonic anhydrase (CA) activity and activities of antioxidant enzymes of Triticum aestivum L. (cv. Samma) under salt stress. Application of 90 mM of NaCl reduced plant growth (plant height, fresh weight (FW) and dry weight (DW), chlorophyll (Chl) a, Chl b, CA activity) and enhanced malondialdehyde (MDA) and Pro concentration. However, the application of SA or Ca alone as well as in combination markedly improved plant growth, photosynthetic pigments, Pro concentration, CA activity and activities of antioxidant enzymes peroxidase (POD), catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR) and ascorbate peroxidase (APX) under salt stress. It was, therefore, concluded that application of SA and Ca alone as well as in combination ameliorated the adverse effect of salinity, while combined application proved more effective to reduce the oxidative stress generated by NaCl through reduced MDA accumulation, Chl a/b ratio and Chls degradation and enhanced activities of antioxidant enzymes.