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Park J, An G, Lee H, Park S, Ham J, Bazer FW, Song G, Lim W. Beta-cyfluthrin impairs implantation process by inducing mitochondrial defects and changes in reactive oxygen species-mediated signaling pathways in porcine trophectoderm and uterine luminal epithelial cells. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 934:173097. [PMID: 38729356 DOI: 10.1016/j.scitotenv.2024.173097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 04/22/2024] [Accepted: 05/07/2024] [Indexed: 05/12/2024]
Abstract
Pyrethroid insecticides, such as beta-cyfluthrin, are used extensively globally, including in households and agriculture, and have been detected in the milk and urine of humans and cattle. Beta-cyfluthrin exhibits toxic effects, including neurotoxicity and male reproductive toxicity; however, few studies have investigated female reproductive toxicity despite its wide environmental distribution. The present study investigates effects of beta-cyfluthrin on implantation in porcine cells (pTr from the trophectoderm and pLE from the endometrial luminal epithelium). To identify the various physiological changes induced by beta-cyfluthrin, such as apoptosis and lipid peroxidation, flow cytometry analysis and immunofluorescence were performed with various reagents. In addition, the expression of genes and proteins associated with intracellular changes was confirmed using qRT-PCR and western blotting. Beta-cyfluthrin induced cell-cycle arrest and altered intracellular calcium flux. It also disrupted the mitochondrial function and promoted reactive oxygen species (ROS) production, leading to lipid peroxidation. Moreover, ROS induced by beta-cyfluthrin altered mitogen-activated protein kinase (MAPK) pathways and decreased cell migration capability. The expression levels of genes that are significant during early pregnancy were altered by beta-cyfluthrin in both cell lines. The changes resulted in apoptosis and diminished cell proliferation of pTr and pLE. Collectively, the results imply that beta-cyfluthrin disrupts the implantation process by affecting the physiology of the trophectoderm and endometrial luminal epithelial cells. The present study is the first to reveal the cellular mechanisms of beta-cyfluthrin on the female reproductive system and highlights the need for further in-depth research into its hazards.
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Affiliation(s)
- Junho Park
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Garam An
- Department of Biological Sciences, Institute of Basic Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hojun Lee
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Sunwoo Park
- Department of Plant & Biomaterials Science, Gyeongsang National University, Jinju-si, Gyeongnam 52725, Republic of Korea
| | - Jiyeon Ham
- Division of Animal and Dairy Science, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Fuller W Bazer
- Department of Animal Science, Texas A&M University, College Station, TX 77843-2471, USA
| | - Gwonhwa Song
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea.
| | - Whasun Lim
- Department of Biological Sciences, Institute of Basic Science, Sungkyunkwan University, Suwon 16419, Republic of Korea.
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2
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An G, Park J, Lim W, Song G. Pyridaben impaired cell cycle progression through perturbation of calcium homeostasis and PI3K/Akt pathway in zebrafish hepatocytes. Comp Biochem Physiol C Toxicol Pharmacol 2024; 276:109799. [PMID: 37993010 DOI: 10.1016/j.cbpc.2023.109799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 10/29/2023] [Accepted: 11/15/2023] [Indexed: 11/24/2023]
Abstract
Environmental pollution caused by pesticides is a growing concern. Pyridaben, a widely used organochlorine insecticide, is a representative water pollutant. Owing to its extensive usage, it has been detected in various aquatic ecosystems, including rivers and oceans. Pyridaben is highly toxic to aquatic organisms; however, the mechanism of its toxicity in the liver, which is important in toxicant metabolism, has not been studied. Therefore, we employed zebrafish and its well-characterized liver cell line, ZFL to assess pyridaben hepatotoxicity and explore its potential mechanisms of action. Pyridaben led to reduction of the liver size and fluorescence intensity of dsRed-labeled Tg (fabp10a:dsRed) zebrafish. It reduced the viability and proliferation of ZFL cells in vitro by inducing apoptosis and cell cycle arrest. These changes might be primarily linked to uncontrolled intracellular calcium flow in ZFL cells exposed to pyridaben. Additionally, it also downregulates the PI3K/Akt signaling cascade, leading to the inactivation of Gsk3β and nuclear translocation of β-catenin. Taken together, our findings suggest that pyridaben could have hepatotoxic effects on aquatic organisms. This study is the first to provide insight into the hepatotoxic mechanism of pyridaben using both in vivo and in vitro models.
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Affiliation(s)
- Garam An
- Institute of Animal Molecular Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea; Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Junho Park
- Institute of Animal Molecular Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea; Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Whasun Lim
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea.
| | - Gwonhwa Song
- Institute of Animal Molecular Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea; Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea.
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3
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George LF, Follmer ML, Fontenoy E, Moran HR, Brown JR, Ozekin YH, Bates EA. Endoplasmic Reticulum Calcium Mediates Drosophila Wing Development. Bioelectricity 2023; 5:290-306. [PMID: 38143873 PMCID: PMC10733776 DOI: 10.1089/bioe.2022.0036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2023] Open
Abstract
Background The temporal dynamics of morphogen presentation impacts transcriptional responses and tissue patterning. However, the mechanisms controlling morphogen release are far from clear. We found that inwardly rectifying potassium (Irk) channels regulate endogenous transient increases in intracellular calcium and bone morphogenetic protein (BMP/Dpp) release for Drosophila wing development. Inhibition of Irk channels reduces BMP/Dpp signaling, and ultimately disrupts wing morphology. Ion channels impact development of several tissues and organisms in which BMP signaling is essential. In neurons and pancreatic beta cells, Irk channels modulate membrane potential to affect intracellular Ca++ to control secretion of neurotransmitters and insulin. Based on Irk activity in neurons, we hypothesized that electrical activity controls endoplasmic reticulum (ER) Ca++ release into the cytoplasm to regulate the release of BMP. Materials and Methods To test this hypothesis, we reduced expression of four proteins that control ER calcium, Stromal interaction molecule 1 (Stim), Calcium release-activated calcium channel protein 1 (Orai), SarcoEndoplasmic Reticulum Calcium ATPase (SERCA), small conductance calcium-activated potassium channel (SK), and Bestrophin 2 (Best2) using RNAi and documented wing phenotypes. We use live imaging to study calcium and Dpp release within pupal wings and larval wing discs. Additionally, we employed immunohistochemistry to characterize Small Mothers Against Decapentaplegic (SMAD) phosphorylation downstream of the BMP/Dpp pathway following RNAi knockdown. Results We found that reduced Stim and SERCA function decreases amplitude and frequency of endogenous calcium transients in the wing disc and reduced BMP/Dpp release. Conclusion Our results suggest control of ER calcium homeostasis is required for BMP/Dpp release, and Drosophila wing development.
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Affiliation(s)
- Laura Faith George
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Mikaela Lynn Follmer
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Emily Fontenoy
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Hannah Rose Moran
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Jeremy Ryan Brown
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Yunus H. Ozekin
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Emily Anne Bates
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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4
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George LF, Bates EA. Mechanisms Underlying Influence of Bioelectricity in Development. Front Cell Dev Biol 2022; 10:772230. [PMID: 35237593 PMCID: PMC8883286 DOI: 10.3389/fcell.2022.772230] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 01/07/2022] [Indexed: 12/25/2022] Open
Abstract
To execute the intricate process of development, cells coordinate across tissues and organs to determine where each cell divides and differentiates. This coordination requires complex communication between cells. Growing evidence suggests that bioelectrical signals controlled via ion channels contribute to cell communication during development. Ion channels collectively regulate the transmembrane potential of cells, and their function plays a conserved role in the development of organisms from flies to humans. Spontaneous calcium oscillations can be found in nearly every cell type and tissue, and disruption of these oscillations leads to defects in development. However, the mechanism by which bioelectricity regulates development is still unclear. Ion channels play essential roles in the processes of cell death, proliferation, migration, and in each of the major canonical developmental signaling pathways. Previous reviews focus on evidence for one potential mechanism by which bioelectricity affects morphogenesis, but there is evidence that supports multiple different mechanisms which are not mutually exclusive. Evidence supports bioelectricity contributing to development through multiple different mechanisms. Here, we review evidence for the importance of bioelectricity in morphogenesis and provide a comprehensive review of the evidence for several potential mechanisms by which ion channels may act in developmental processes.
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Affiliation(s)
- Laura Faith George
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States
| | - Emily Anne Bates
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States
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5
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Papp B, Launay S, Gélébart P, Arbabian A, Enyedi A, Brouland JP, Carosella ED, Adle-Biassette H. Endoplasmic Reticulum Calcium Pumps and Tumor Cell Differentiation. Int J Mol Sci 2020; 21:ijms21093351. [PMID: 32397400 PMCID: PMC7247589 DOI: 10.3390/ijms21093351] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 05/01/2020] [Accepted: 05/02/2020] [Indexed: 12/21/2022] Open
Abstract
Endoplasmic reticulum (ER) calcium homeostasis plays an essential role in cellular calcium signaling, intra-ER protein chaperoning and maturation, as well as in the interaction of the ER with other organelles. Calcium is accumulated in the ER by sarco/endoplasmic reticulum calcium ATPases (SERCA enzymes) that generate by active, ATP-dependent transport, a several thousand-fold calcium ion concentration gradient between the cytosol (low nanomolar) and the ER lumen (high micromolar). SERCA enzymes are coded by three genes that by alternative splicing give rise to several isoforms, which can display isoform-specific calcium transport characteristics. SERCA expression levels and isoenzyme composition vary according to cell type, and this constitutes a mechanism whereby ER calcium homeostasis is adapted to the signaling and metabolic needs of the cell, depending on its phenotype, its state of activation and differentiation. As reviewed here, in several normal epithelial cell types including bronchial, mammary, gastric, colonic and choroid plexus epithelium, as well as in mature cells of hematopoietic origin such as pumps are simultaneously expressed, whereas in corresponding tumors and leukemias SERCA3 expression is selectively down-regulated. SERCA3 expression is restored during the pharmacologically induced differentiation of various cancer and leukemia cell types. SERCA3 is a useful marker for the study of cell differentiation, and the loss of SERCA3 expression constitutes a previously unrecognized example of the remodeling of calcium homeostasis in tumors.
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Affiliation(s)
- Bela Papp
- Institut National de la Santé et de la Recherche Médicale, UMR U976, Institut Saint-Louis, 75010 Paris, France
- Institut de Recherche Saint-Louis, Hôpital Saint-Louis, Université de Paris, 75010 Paris, France
- CEA, DRF-Institut Francois Jacob, Department of Hemato-Immunology Research, Hôpital Saint-Louis, 75010 Paris, France;
- Correspondence: or
| | - Sophie Launay
- EA481, UFR Santé, Université de Bourgogne Franche-Comté, 25000 Besançon, France;
| | - Pascal Gélébart
- Department of Clinical Science-Hematology Section, Haukeland University Hospital, University of Bergen, 5021 Bergen, Norway;
| | - Atousa Arbabian
- Laboratoire d’Innovation Vaccins, Institut Pasteur de Paris, 75015 Paris, France;
| | - Agnes Enyedi
- Second Department of Pathology, Semmelweis University, 1091 Budapest, Hungary;
| | - Jean-Philippe Brouland
- Institut Universitaire de Pathologie, Centre Hospitalier Universitaire Vaudois, 1011 Lausanne, Switzerland;
| | - Edgardo D. Carosella
- CEA, DRF-Institut Francois Jacob, Department of Hemato-Immunology Research, Hôpital Saint-Louis, 75010 Paris, France;
| | - Homa Adle-Biassette
- AP-HP, Service d’Anatomie et Cytologie Pathologiques, Hôpital Lariboisière, 75010 Paris, France;
- Université de Paris, NeuroDiderot, Inserm UMR 1141, 75019 Paris, France
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6
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Xiao X, Liu HX, Shen K, Cao W, Li XQ. Canonical Transient Receptor Potential Channels and Their Link with Cardio/Cerebro-Vascular Diseases. Biomol Ther (Seoul) 2017; 25:471-481. [PMID: 28274093 PMCID: PMC5590790 DOI: 10.4062/biomolther.2016.096] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 12/04/2016] [Accepted: 12/27/2016] [Indexed: 12/29/2022] Open
Abstract
The canonical transient receptor potential channels (TRPCs) constitute a series of nonselective cation channels with variable degrees of Ca2+ selectivity. TRPCs consist of seven mammalian members, TRPC1, TRPC2, TRPC3, TRPC4, TRPC5, TRPC6, and TRPC7, which are further divided into four subtypes, TRPC1, TRPC2, TRPC4/5, and TRPC3/6/7. These channels take charge of various essential cell functions such as contraction, relaxation, proliferation, and dysfunction. This review, organized into seven main sections, will provide an overview of current knowledge about the underlying pathogenesis of TRPCs in cardio/cerebrovascular diseases, including hypertension, pulmonary arterial hypertension, cardiac hypertrophy, atherosclerosis, arrhythmia, and cerebrovascular ischemia reperfusion injury. Collectively, TRPCs could become a group of drug targets with important physiological functions for the therapy of human cardio/cerebro-vascular diseases.
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Affiliation(s)
- Xiong Xiao
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an 710032, China
| | - Hui-Xia Liu
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an 710032, China.,Cadet Brigade, Fourth Military Medical University, Xi'an 710032, China
| | - Kuo Shen
- Cadet Brigade, Fourth Military Medical University, Xi'an 710032, China
| | - Wei Cao
- Department of Natural Medicine & Institute of Materia Medica, School of Pharmacy, Fourth Military Medical University, Xi'an 710032, China
| | - Xiao-Qiang Li
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an 710032, China
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7
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Calcium signaling and cell cycle: Progression or death. Cell Calcium 2017; 70:3-15. [PMID: 28801101 DOI: 10.1016/j.ceca.2017.07.006] [Citation(s) in RCA: 132] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 07/23/2017] [Accepted: 07/23/2017] [Indexed: 12/12/2022]
Abstract
Cytosolic Ca2+ concentration levels fluctuate in an ordered manner along the cell cycle, in line with the fact that Ca2+ is involved in the regulation of cell proliferation. Cell proliferation should be an error-free process, yet is endangered by mistakes. In fact, a complex network of proteins ensures that cell cycle does not progress until the previous phase has been successfully completed. Occasionally, errors occur during the cell cycle leading to cell cycle arrest. If the error is severe, and the cell cycle checkpoints work perfectly, this results into cellular demise by activation of apoptotic or non-apoptotic cell death programs. Cancer is characterized by deregulated proliferation and resistance against cell death. Ca2+ is a central key to these phenomena as it modulates signaling pathways that control oncogenesis and cancer progression. Here, we discuss how Ca2+ participates in the exogenous and endogenous signals controlling cell proliferation, as well as in the mechanisms by which cells die if irreparable cell cycle damage occurs. Moreover, we summarize how Ca2+ homeostasis remodeling observed in cancer cells contributes to deregulated cell proliferation and resistance to cell death. Finally, we discuss the possibility to target specific components of Ca2+ signal pathways to obtain cytostatic or cytotoxic effects.
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8
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Verma D, Murmu A, Gourinath S, Bhattacharya A, Chary KVR. Structure of Ca2+-binding protein-6 from Entamoeba histolytica and its involvement in trophozoite proliferation regulation. PLoS Pathog 2017; 13:e1006332. [PMID: 28505197 PMCID: PMC5444848 DOI: 10.1371/journal.ppat.1006332] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 05/25/2017] [Accepted: 04/03/2017] [Indexed: 12/01/2022] Open
Abstract
Cell cycle of Entamoeba histolytica, the etiological agent of amoebiasis, follows a novel pathway, which includes nuclear division without the nuclear membrane disassembly. We report a nuclear localized Ca2+-binding protein from E. histolytica (abbreviated hereafter as EhCaBP6), which is associated with microtubules. We determined the 3D solution NMR structure of EhCaBP6, and identified one unusual, one canonical and two non-canonical cryptic EF-hand motifs. The cryptic EF-II and EF-IV pair with the Ca2+-binding EF-I and EF-III, respectively, to form a two-domain structure similar to Calmodulin and Centrin proteins. Downregulation of EhCaBP6 affects cell proliferation by causing delays in transition from G1 to S phase, and inhibition of DNA synthesis and cytokinesis. We also demonstrate that EhCaBP6 modulates microtubule dynamics by increasing the rate of tubulin polymerization. Our results, including structural inferences, suggest that EhCaBP6 is an unusual CaBP involved in regulating cell proliferation in E. histolytica similar to nuclear Calmodulin. E. histolytica, the etiological agent of amoebiasis, is a protozoan parasite responsible for around 100,000 deaths per year in developing nations. Though the organism has been identified more than 100 years back, there is not much understanding about the biology of this organism. Calcium signaling plays an important role in the biology of this organism. Here we show structure-functional relationship of one of the Ca2+-binding proteins (abbreviated as EhCaBP6) and suggest its involvement in cell division in this parasite. EhCaBP6, a nucleo-cytosolic Ca2+-binding protein, is a microtubule end binding protein and overexpression of its gene induces an increase in number of microtubular assemblies in E. histolytica. Cell division cycle in E. histolytica occurs along the microtubular structures without disruption of nuclear envelope. Occurrence of multinucleated cells in culture suggests duplication and reduplication of nuclear DNA without cytokinesis. Although Kinesin like protein (Klp1), Formin1 and EhCaBP6 were shown to be part of the microtubular assembly, their role in regulation of the cell cycle is not yet documented. Further, E. histolytica does not have a typical CaM like protein. However, the 3D structure of EhCaBP6 with two Ca2+-binding sites is similar to CaM, in spite of their low sequence similarity. Here, we demonstrate that EhCaBP6 regulates cell cycle specifically by facilitating DNA synthesis, transition from G1 to S phase and cytokinesis. The structural and functional similarity between EhCaBP6 and CaM suggests EhCaBP6 to be a functional homologue of nuclear CaM with important roles in regulation of cell cycle.
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Affiliation(s)
- Deepshikha Verma
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, India
- Tata Institute of Fundamental Research, Center for Interdisciplinary Sciences, Hyderabad, India
| | - Aruna Murmu
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | | | - Alok Bhattacharya
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Kandala V. R. Chary
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, India
- Tata Institute of Fundamental Research, Center for Interdisciplinary Sciences, Hyderabad, India
- * E-mail:
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9
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Smith KA, Voiriot G, Tang H, Fraidenburg DR, Song S, Yamamura H, Yamamura A, Guo Q, Wan J, Pohl NM, Tauseef M, Bodmer R, Ocorr K, Thistlethwaite PA, Haddad GG, Powell FL, Makino A, Mehta D, Yuan JXJ. Notch Activation of Ca(2+) Signaling in the Development of Hypoxic Pulmonary Vasoconstriction and Pulmonary Hypertension. Am J Respir Cell Mol Biol 2015; 53:355-67. [PMID: 25569851 DOI: 10.1165/rcmb.2014-0235oc] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Hypoxic pulmonary vasoconstriction (HPV) is an important physiological response that optimizes the ventilation/perfusion ratio. Chronic hypoxia causes vascular remodeling, which is central to the pathogenesis of hypoxia-induced pulmonary hypertension (HPH). We have previously shown that Notch3 is up-regulated in HPH and that activation of Notch signaling enhances store-operated Ca(2+) entry (SOCE), an important mechanism that contributes to pulmonary arterial smooth muscle cell (PASMC) proliferation and contraction. Here, we investigate the role of Notch signaling in HPV and hypoxia-induced enhancement of SOCE. We examined SOCE in human PASMCs exposed to hypoxia and pulmonary arterial pressure in mice using the isolated perfused/ventilated lung method. Wild-type and canonical transient receptor potential (TRPC) 6(-/-) mice were exposed to chronic hypoxia to induce HPH. Inhibition of Notch signaling with a γ-secretase inhibitor attenuates hypoxia-enhanced SOCE in PASMCs and hypoxia-induced increase in pulmonary arterial pressure. Our results demonstrate that hypoxia activates Notch signaling and up-regulates TRPC6 channels. Additionally, treatment with a Notch ligand can mimic hypoxic responses. Finally, inhibition of TRPC6, either pharmacologically or genetically, attenuates HPV, hypoxia-enhanced SOCE, and the development of HPH. These results demonstrate that hypoxia-induced activation of Notch signaling mediates HPV and the development of HPH via functional activation and up-regulation of TRPC6 channels. Understanding the molecular mechanisms that regulate cytosolic free Ca(2+) concentration and PASMC proliferation is critical to elucidation of the pathogenesis of HPH. Targeting Notch regulation of TRPC6 will be beneficial in the development of novel therapies for pulmonary hypertension associated with hypoxia.
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Affiliation(s)
- Kimberly A Smith
- Departments of 1 Medicine and.,2 Pharmacology, University of Illinois at Chicago, Chicago, Illinois
| | - Guillaume Voiriot
- Departments of 1 Medicine and.,2 Pharmacology, University of Illinois at Chicago, Chicago, Illinois
| | - Haiyang Tang
- Departments of 1 Medicine and.,2 Pharmacology, University of Illinois at Chicago, Chicago, Illinois.,3 Division of Translational and Regenerative Medicine, Department of Medicine and
| | - Dustin R Fraidenburg
- Departments of 1 Medicine and.,2 Pharmacology, University of Illinois at Chicago, Chicago, Illinois
| | - Shanshan Song
- Departments of 1 Medicine and.,2 Pharmacology, University of Illinois at Chicago, Chicago, Illinois.,3 Division of Translational and Regenerative Medicine, Department of Medicine and
| | - Hisao Yamamura
- Departments of 1 Medicine and.,2 Pharmacology, University of Illinois at Chicago, Chicago, Illinois.,4 Department of Molecular & Cellular Pharmacology, Nagoya City University, Nagoya, Japan
| | - Aya Yamamura
- Departments of 1 Medicine and.,2 Pharmacology, University of Illinois at Chicago, Chicago, Illinois.,5 Department of Pharmacy, Kinjo Gakuin University, Nagoya, Japan
| | - Qiang Guo
- Departments of 1 Medicine and.,2 Pharmacology, University of Illinois at Chicago, Chicago, Illinois.,6 First Affiliated Hospital, Soochow University, Suzhou, China
| | - Jun Wan
- Departments of 1 Medicine and.,2 Pharmacology, University of Illinois at Chicago, Chicago, Illinois
| | - Nicole M Pohl
- Departments of 1 Medicine and.,2 Pharmacology, University of Illinois at Chicago, Chicago, Illinois
| | - Mohammad Tauseef
- 2 Pharmacology, University of Illinois at Chicago, Chicago, Illinois
| | - Rolf Bodmer
- 7 Development, Aging, and Regeneration Program, Sanford-Burnham Institute for Medical Research, La Jolla, California
| | - Karen Ocorr
- 7 Development, Aging, and Regeneration Program, Sanford-Burnham Institute for Medical Research, La Jolla, California
| | | | | | - Frank L Powell
- 10 Medicine, University of California, San Diego, La Jolla, California; and
| | - Ayako Makino
- Departments of 1 Medicine and.,11 Department of Physiology, The University of Arizona College of Medicine, Tucson, Arizona
| | - Dolly Mehta
- 2 Pharmacology, University of Illinois at Chicago, Chicago, Illinois
| | - Jason X-J Yuan
- Departments of 1 Medicine and.,2 Pharmacology, University of Illinois at Chicago, Chicago, Illinois.,3 Division of Translational and Regenerative Medicine, Department of Medicine and.,11 Department of Physiology, The University of Arizona College of Medicine, Tucson, Arizona
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10
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Guo S, Feng Z. Galectin-3 mediates the effect of PDGF on pulmonary arterial hypertension. Int J Clin Exp Med 2015; 8:15302-7. [PMID: 26629018 PMCID: PMC4658907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Accepted: 09/10/2015] [Indexed: 06/05/2023]
Abstract
AIMS The present study aimed to perform in vitro experiments to investigate whether Galectin-3 (Gal-3) mediates the effect of platelet-derived growth factor (PDGF) on pulmonary arterial smooth muscle cells (PASMC) proliferation, apoptosis and migration, and to reveal the mechanism of how Gal-3 functions in the pathogenesis of pulmonary arterial hypertension (PAH). METHODS Pulmonary arterial smooth muscle cells (PASMC) were treated with various concentration of PDGF for indicated times, and the expression of Gal-3 was analyzed by western blotting. Gal-3 siRNA was transfected into the PASMC to knock down endogenous Gal-3. MTT assay was performed to examine cell proliferation. Transwell-migration assay was used to determine cell migration ability. Cell apoptosis rate was determined by flow cytometric analysis. RESULTS The result showed that the expression of Gal-3 protein was induced by PDGF in a dose- and a time-dependent manner. PDGF contributes to the progression of PAH by inducing cell proliferation and migration, as well as inhibiting cell apoptosis of PASMC. However, these effects of PDGF on PASMC were attenuated by Gal-3 knockdown. CONCLUSION The present study provided potential evidence about the role of Gal-3 in the pathophysiological mechanisms of PAH. This study firstly demonstrated that Gal-3 could be induced by PDGF in PASMC, and mediates the effect of PDGF on PASMC proliferation, apoptosis and migration, thus contributing to the pathogenesis of PAH.
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Affiliation(s)
- Shaomei Guo
- Jiangxi Medical College of Nanchang UniversityNanchang 330031, Jiangxi, P. R. China
- Department of Respiration, Jiangxi Provincial People’s HospitalNanchang 330006, Jiangxi, P. R. China
| | - Ziming Feng
- Jiangxi Medical College of Nanchang UniversityNanchang 330031, Jiangxi, P. R. China
- Department of Orthopaedics, Jiangxi Provincial People’s HospitalNanchang 330006, Jiangxi, P. R. China
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11
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Contreras-Leal E, Hernández-Oliveras A, Flores-Peredo L, Zarain-Herzberg Á, Santiago-García J. Histone deacetylase inhibitors promote the expression of ATP2A3
gene in breast cancer cell lines. Mol Carcinog 2015; 55:1477-85. [DOI: 10.1002/mc.22402] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 07/26/2015] [Accepted: 08/17/2015] [Indexed: 12/31/2022]
Affiliation(s)
- Erika Contreras-Leal
- Programa de Doctorado en Ciencias Biomédicas; Universidad Veracruzana; Veracruz México
- Instituto de Investigaciones Biol; ó; gicas; Universidad Veracruzana; Xalapa Veracruz México
| | | | - Lucía Flores-Peredo
- Departamento de Bioquímica; Facultad de Medicina; Universidad Nacional Autónoma de México; México
| | - Ángel Zarain-Herzberg
- Departamento de Bioquímica; Facultad de Medicina; Universidad Nacional Autónoma de México; México
| | - Juan Santiago-García
- Instituto de Investigaciones Biol; ó; gicas; Universidad Veracruzana; Xalapa Veracruz México
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12
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Modelling cell cycle synchronisation in networks of coupled radial glial cells. J Theor Biol 2015; 377:85-97. [PMID: 25908204 DOI: 10.1016/j.jtbi.2015.04.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 02/26/2015] [Accepted: 04/08/2015] [Indexed: 12/31/2022]
Abstract
Radial glial cells play a crucial role in the embryonic mammalian brain. Their proliferation is thought to be controlled, in part, by ATP mediated calcium signals. It has been hypothesised that these signals act to locally synchronise cell cycles, so that clusters of cells proliferate together, shedding daughter cells in uniform sheets. In this paper we investigate this cell cycle synchronisation by taking an ordinary differential equation model that couples the dynamics of intracellular calcium and the cell cycle and extend it to populations of cells coupled via extracellular ATP signals. Through bifurcation analysis we show that although ATP mediated calcium release can lead to cell cycle synchronisation, a number of other asynchronous oscillatory solutions including torus solutions dominate the parameter space and cell cycle synchronisation is far from guaranteed. Despite this, numerical results indicate that the transient and not the asymptotic behaviour of the system is important in accounting for cell cycle synchronisation. In particular, quiescent cells can be entrained on to the cell cycle via ATP mediated calcium signals initiated by a driving cell and crucially will cycle in near synchrony with the driving cell for the duration of neurogenesis. This behaviour is highly sensitive to the timing of ATP release, with release at the G1/S phase transition of the cell cycle far more likely to lead to near synchrony than release during mid G1 phase. This result, which suggests that ATP release timing is critical to radial glia cell cycle synchronisation, may help us to understand normal and pathological brain development.
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Farrukh MR, Nissar UA, Afnan Q, Rafiq RA, Sharma L, Amin S, Kaiser P, Sharma PR, Tasduq SA. Oxidative stress mediated Ca(2+) release manifests endoplasmic reticulum stress leading to unfolded protein response in UV-B irradiated human skin cells. J Dermatol Sci 2014; 75:24-35. [PMID: 24794973 DOI: 10.1016/j.jdermsci.2014.03.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 02/21/2014] [Accepted: 03/31/2014] [Indexed: 12/13/2022]
Abstract
BACKGROUND Exposure of skin to ultraviolet (UV) radiation, an environmental stressor induces number of adverse biological effects (photodamage), including cancer. The damage induced by UV-irradiation in skin cells is initiated by the photochemical generation of reactive oxygen species (ROS) and induction of endoplasmic reticulum (ER) stress and consequent activation of unfolded protein response (UPR). OBJECTIVE To decipher cellular and molecular events responsible for UV-B mediated ER stress and UPR activation in skin cells. METHODS The study was performed on human skin fibroblast (Hs68) and keratinocyte (HaCaT) cells exposed to UV-B radiations in lab conditions. Different parameters of UVB induced cellular and molecular changes were analyzed using Western-blotting, microscopic studies and flow cytometry. RESULTS Our results depicted that UV-B induces an immediate ROS generation that resulted in emptying of ER Ca(2+) stores inducing ER stress and activation of PERK-peIF2α-CHOP pathway. Quenching ROS generation by anti-oxidants prevented Ca(2+) release and subsequent induction of ER stress and UPR activation. UV-B irradiation induced PERK dependent G2/M phase cell cycle arrest in Hs68 and G1/S phase cell cycle arrest in HaCaT. Also our study reflects that UV-B exposure leads to loss of mitochondrial membrane potential, activation of apoptotic cascade as evident by AnnexinV/PI staining, decreased expression of Bcl-2 and increased cleavage of PARP-1 protein. CONCLUSION UV-B induced Ca(2+) deficit within ER lumen was mediated by immediate ROS generation. Insufficient Ca(2+) concentration within ER lumen developed ER stress leading to UPR activation. These changes were reversed by use of anti-oxidants which quench ROS.
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Affiliation(s)
- Mufti R Farrukh
- PK-PD and Toxicology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu Tawi, Jammu and Kashmir, India
| | - Ul A Nissar
- PK-PD and Toxicology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu Tawi, Jammu and Kashmir, India; Academy of Scientific and Innovative Research (AcSIR), New Delhi, India
| | - Quadri Afnan
- PK-PD and Toxicology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu Tawi, Jammu and Kashmir, India
| | - Rather A Rafiq
- PK-PD and Toxicology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu Tawi, Jammu and Kashmir, India
| | - Love Sharma
- PK-PD and Toxicology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu Tawi, Jammu and Kashmir, India; Academy of Scientific and Innovative Research (AcSIR), New Delhi, India
| | - Shajrul Amin
- Department of Biochemistry, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Peerzada Kaiser
- PK-PD and Toxicology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu Tawi, Jammu and Kashmir, India
| | - Parduman R Sharma
- Cancer Pharmacology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu Tawi, Jammu and Kashmir, India
| | - Sheikh A Tasduq
- PK-PD and Toxicology Division, CSIR-Indian Institute of Integrative Medicine, Canal Road, Jammu Tawi, Jammu and Kashmir, India; Academy of Scientific and Innovative Research (AcSIR), New Delhi, India.
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14
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Revermann M, Neofitidou S, Kirschning T, Schloss M, Brandes RP, Hofstetter C. Inhalation of the BK(Ca)-opener NS1619 attenuates right ventricular pressure and improves oxygenation in the rat monocrotaline model of pulmonary hypertension. PLoS One 2014; 9:e86636. [PMID: 24497961 PMCID: PMC3909005 DOI: 10.1371/journal.pone.0086636] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Accepted: 12/11/2013] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Right heart failure is a fatal consequence of chronic pulmonary hypertension (PH). The development of PH is characterized by increased proliferation of vascular cells, in particular pulmonary artery smooth muscle cells (PASMCs) and pulmonary artery endothelial cells. In the course of PH, an escalated right ventricular (RV) afterload occurs, which leads to increased perioperative morbidity and mortality. BK(Ca) channels are ubiquitously expressed in vascular smooth muscle cells and their opening induces cell membrane hyperpolarization followed by vasodilation. Moreover, BK activation induces anti-proliferative effects in a multitude of cell types. On this basis, we hypothesized that treatment with the nebulized BK channel opener NS1619 might be a therapy option for pulmonary hypertension and tested this in rats. METHODS (1) Rats received monocrotaline injection for PH induction. Twenty-four days later, rats were anesthetized and NS1619 or the solvent was administered by inhalation. Systemic hemodynamic parameters, RV hemodynamic parameters, and blood gas analyses were measured before as well as 30 and 120 minutes after inhalation. (2) Rat PASMCs were stimulated with PDGF-BB in the presence and absence of NS1619. AKT, ERK1 and ERK2 activation were investigated by western blot analyses, and relative cell number was determined 48 hours after stimulation. RESULTS Inhalation of a 12 µM and 100 µM NS1619 solution significantly reduced RV pressure without affecting systemic arterial pressure. Blood gas analyses demonstrated significantly reduced carbon dioxide and improved oxygenation in NS1619-treated animals pointing towards a considerable pulmonary shunt-reducing effect. In PASMC's, NS1619 (100 µM) significantly attenuated PASMC proliferation by a pathway independent of AKT and ERK1/2 activation. CONCLUSION NS1619 inhalation reduces RV pressure and improves oxygen supply and its application inhibits PASMC proliferation in vitro. Hence, BK opening might be a novel option for the treatment of pulmonary hypertension.
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MESH Headings
- Administration, Inhalation
- Animals
- Becaplermin
- Benzimidazoles/administration & dosage
- Benzimidazoles/pharmacology
- Blotting, Western
- Cell Proliferation/drug effects
- Cells, Cultured
- Hemodynamics/drug effects
- Hypertension, Pulmonary/chemically induced
- Hypertension, Pulmonary/physiopathology
- Hypertension, Pulmonary/prevention & control
- Large-Conductance Calcium-Activated Potassium Channels/metabolism
- Male
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3/metabolism
- Monocrotaline
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Oxygen/metabolism
- Proto-Oncogene Proteins c-akt/metabolism
- Proto-Oncogene Proteins c-sis/pharmacology
- Pulmonary Artery/cytology
- Rats
- Rats, Sprague-Dawley
- Ventricular Dysfunction, Right/physiopathology
- Ventricular Dysfunction, Right/prevention & control
- Ventricular Pressure/drug effects
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Affiliation(s)
- Marc Revermann
- Department of Anesthesiology and Critical Care Medicine, University Hospital Mannheim, Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
- Institute for Cardiovascular Physiology, Medical Faculty of the Goethe-University Frankfurt, Frankfurt, Germany
| | - Skevi Neofitidou
- Department of Anesthesiology and Critical Care Medicine, University Hospital Mannheim, Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Thomas Kirschning
- Department of Anesthesiology and Critical Care Medicine, University Hospital Mannheim, Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Manuel Schloss
- Institute for Cardiovascular Physiology, Medical Faculty of the Goethe-University Frankfurt, Frankfurt, Germany
| | - Ralf P. Brandes
- Institute for Cardiovascular Physiology, Medical Faculty of the Goethe-University Frankfurt, Frankfurt, Germany
| | - Christian Hofstetter
- Department of Anesthesiology and Critical Care Medicine, University Hospital Mannheim, Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
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15
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B L, R.K Y, G.S J, H.-R K, H.-J C. The characteristics of Bax inhibitor-1 and its related diseases. Curr Mol Med 2014; 14:603-15. [PMID: 24894176 PMCID: PMC4083451 DOI: 10.2174/1566524014666140603101113] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 10/01/2013] [Accepted: 11/24/2013] [Indexed: 11/28/2022]
Abstract
Bax inhibitor-1 (BI-1) is an evolutionarily-conserved endoplasmic reticulum protein. The expression of BI-1 in mammalian cells suppresses apoptosis induced by Bax, a pro-apoptotic member of the Bcl-2 family. BI-1 has been shown to be associated with calcium (Ca(2+)) levels, reactive oxygen species (ROS) production, cytosolic acidification, and autophagy as well as endoplasmic reticulum stress signaling pathways. According to both in vitro and clinical studies, BI-1 promotes the characteristics of cancers. In other diseases, BI-1 has also been shown to regulate insulin resistance, adipocyte differentiation, hepatic dysfunction and depression. However, the roles of BI-1 in these disease conditions are not fully consistent among studies. Until now, the molecular mechanisms of BI-1 have not directly explained with regard to how these conditions can be regulated. Therefore, this review investigates the physiological role of BI-1 through molecular mechanism studies and its application in various diseases.
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Affiliation(s)
- Li B
- Department of Pharmacology, Medical School, Chonbuk National University, Jeonju, 561-181, Republic of Korea
| | - Yadav R.K
- Department of Pharmacology, Medical School, Chonbuk National University, Jeonju, 561-181, Republic of Korea
| | - Jeong G.S
- Department of Pharmacology, Medical School, Chonbuk National University, Jeonju, 561-181, Republic of Korea
| | - Kim H.-R
- Department of Dental Pharmacology and Wonkwang Dental Research Institute, School of Dentistry, Wonkwang University, Iksan, 570-749, Republic of Korea
| | - Chae H.-J
- Department of Pharmacology, Medical School, Chonbuk National University, Jeonju, 561-181, Republic of Korea
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16
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Borowiec AS, Bidaux G, Tacine R, Dubar P, Pigat N, Delcourt P, Mignen O, Capiod T. Are Orai1 and Orai3 channels more important than calcium influx for cell proliferation? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:464-72. [PMID: 24321771 DOI: 10.1016/j.bbamcr.2013.11.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 11/09/2013] [Accepted: 11/27/2013] [Indexed: 12/19/2022]
Abstract
Transformed and tumoral cells share the characteristic of being able to proliferate even when external calcium concentration is very low. We have investigated whether Human Embryonic Kidney 293 cells, human hepatoma cell Huh-7 and HeLa cells were able to proliferate when kept 72h in complete culture medium without external calcium. Our data showed that cell proliferation rate was similar over a range of external calcium concentration (2μM to 1.8mM). Incubation in the absence of external calcium for 72h had no significant effect on endoplasmic reticulum (ER) Ca(2+) contents but resulted in a significant decrease in cytosolic free calcium concentration in all 3 cell types. Cell proliferation rates were dependent on Orai1 and Orai3 expression levels in HEK293 and HeLa cells. Silencing Orai1 or Orai3 resulted in a 50% reduction in cell proliferation rate. Flow cytometry analysis showed that Orai3 induced a small but significant increase in cell number in G2/M phase. RO-3306, a cdk-1 inhibitor, induced a 90% arrest in G2/M reversible in less than 15min. Our data showed that progression through G2/M phase after release from RO-3306-induced cell cycle arrest was slower in both Orai1 and Orai3 knock-downs. Overexpressing Orai1, Orai3 and the dominant negative non-permeant mutants E106Q-Orai1 and E81Q-Orai3 induced a 50% increase in cell proliferation rate in HEK293 cells. Our data clearly demonstrated that Orai1 and Orai3 proteins are more important than calcium influx to control cell proliferation in some cell lines and that this process is probably independent of ICRAC and Iarc.
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Affiliation(s)
| | - Gabriel Bidaux
- INSERM, U1003, IFR147, Univ Lille 1, Villeneuve d'Ascq F-59655, France
| | - Rachida Tacine
- INSERM U807, Hôpital Necker Enfants Malades, Université Paris 5, 156 rue de Vaugirard, Paris F-75730, France
| | - Pauline Dubar
- INSERM U613, Université Bretagne Occidentale, 46 rue Felix Le Dantec, Brest F-29218, France
| | - Natascha Pigat
- INSERM U845, Growth and Signalling Research Center, Université Paris 5, Bâtiment Leriche, 96 rue Didot, Paris F-75993, France
| | - Philippe Delcourt
- INSERM, U1003, IFR147, Univ Lille 1, Villeneuve d'Ascq F-59655, France
| | - Olivier Mignen
- INSERM U613, Université Bretagne Occidentale, 46 rue Felix Le Dantec, Brest F-29218, France
| | - Thierry Capiod
- INSERM, U1003, IFR147, Univ Lille 1, Villeneuve d'Ascq F-59655, France; INSERM U807, Hôpital Necker Enfants Malades, Université Paris 5, 156 rue de Vaugirard, Paris F-75730, France; INSERM U845, Growth and Signalling Research Center, Université Paris 5, Bâtiment Leriche, 96 rue Didot, Paris F-75993, France.
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17
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Shen B, Zhu J, Zhang J, Jiang F, Wang Z, Zhang Y, Li J, Huang D, Ke D, Ma R, Du J. Attenuated mesangial cell proliferation related to store-operated Ca2+ entry in aged rat: the role of STIM 1 and Orai 1. AGE (DORDRECHT, NETHERLANDS) 2013; 35:2193-2202. [PMID: 23334602 PMCID: PMC3824990 DOI: 10.1007/s11357-013-9511-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 01/09/2013] [Indexed: 06/01/2023]
Abstract
Store-operated Ca(2+) entry (SOCE) is a common and ubiquitous mechanism regulating Ca(2+) influx into cells and participates in numerous biological processes including cell proliferation. Glomerular mesangial cells (GMCs) play a role in the regulation of the glomerular filtration rate. From a clinical point of view, many physiological functions alter with age. In the present study, we used angiotensin II, glucagon, and the sarco/endoplasmic reticulum membrane Ca(2+) pump inhibitor thapsigargin to deplete the internal Ca(2+) stores for the activation of SOCE. We found that SOCE was significantly attenuated in GMCs from aged (22-month-old) rats. The expression of SOCE-related components, stromal interaction molecule 1 (STIM 1) and Orai 1, in freshly isolated glomeruli notably decreased, and STIM 1 and Orai 1 puncta formation significantly reduced in primary-cultured GMCs in aged rats. Moreover, specific knockdown of STIM 1 and Orai 1 by small interfering RNA markedly suppressed SOCE and cell proliferation of GMCs isolated from young (3-month-old) rats. We conclude that the attenuation of GMCs proliferation can be attributed to the decreased SOCE partially caused by reduced expression of STIM 1 and Orai 1.
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Affiliation(s)
- Bing Shen
- />Department of Physiology, Anhui Medical University, Hefei, China
| | - Jinhang Zhu
- />Department of Physiology, Anhui Medical University, Hefei, China
| | - Jin Zhang
- />Department of Physiology, Anhui Medical University, Hefei, China
| | - Feifei Jiang
- />Department of Physiology, Anhui Medical University, Hefei, China
| | - Zhaoyi Wang
- />Department of Physiology, Anhui Medical University, Hefei, China
| | - Yang Zhang
- />Comprehensive Surgery, Anhui Provincial Hospital, Hefei, 230032 China
| | - Jie Li
- />Department of Physiology, Anhui Medical University, Hefei, China
| | - Dake Huang
- />Comprehensive Laboratory of Basic Medical School, Anhui Medical University, Hefei, China
| | - Daoping Ke
- />Department of Physiology, Anhui Medical University, Hefei, China
| | - Rong Ma
- />Department of Integrative Physiology, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX USA
| | - Juan Du
- />Department of Physiology, Anhui Medical University, Hefei, China
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18
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Mallampalli RK, Kaercher L, Snavely C, Pulijala R, Chen BB, Coon T, Zhao J, Agassandian M. Fbxl12 triggers G1 arrest by mediating degradation of calmodulin kinase I. Cell Signal 2013; 25:2047-59. [PMID: 23707388 DOI: 10.1016/j.cellsig.2013.05.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Accepted: 05/07/2013] [Indexed: 12/18/2022]
Abstract
Cell cycle progression through its regulatory control by changes in intracellular Ca(2+) levels at the G1/S transition mediates cellular proliferation and viability. Ca(2+)/CaM-dependent kinase 1 (CaMKI) appears critical in regulating the assembly of the cyclin D1/cdk4 complex essential for G1 progression, but how this occurs is unknown. Cyclin D1/cdk4 assembly in the early G1 phase is also regulated via binding to p27. Here, we show that a ubiquitin E3 ligase component, F-box protein Fbxl12, mediates CaMKI degradation via a proteasome-directed pathway leading to disruption of cyclin D1/cdk4 complex assembly and resultant G1 arrest in lung epithelia. We also demonstrate that i) CaMKI phosphorylates p27 at Thr(157) and Thr(198) in human cells and at Thr(170) and Thr(197) in mouse cells to modulate its subcellular localization; ii) Fbxl12-induced CaMKI degradation attenuates p27 phosphorylation at these sites in early G1 and iii) activation of CaMKI during G1 transition followed by p27 phosphorylation appears to be upstream to other p27 phosphorylation events, an effect abrogated by Fbxl12 overexpression. Lastly, known inducers of G1 arrest significantly increase Fbxl12 levels in cells. Thus, Fbxl12 may be a previously uncharacterized, functional growth inhibitor regulating cell cycle progression that might be used for mechanism-based therapy.
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Affiliation(s)
- Rama K Mallampalli
- Department of Medicine, Acute Lung Injury Center of Excellence, The University of Pittsburgh, Pittsburgh, PA 15213, USA
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19
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Identification and characterization of a kunzeaol synthase from Thapsia garganica: implications for the biosynthesis of the pharmaceutical thapsigargin. Biochem J 2012; 448:261-71. [DOI: 10.1042/bj20120654] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Thapsigargin is a major terpenoid constituent of Thapsia garganica root. Owing to its potent antagonistic effect on the sarcoplasmic/endoplasmic reticulum Ca2+-ATPase, thapsigargin has been widely used to study Ca2+ signalling and is also a potential drug for prostate cancer. Despite its importance, thapsigargin biosynthesis in T. garganica remains unknown. In order to decipher thapsigargin biosynthesis, deep transcript sequencing (454 and Illumina) of the T. garganica root was performed, and two terpene synthases (TgTPS1/2) were identified. Functional characterization of their encoded enzymes in a metabolically engineered yeast revealed that TgTPS1 synthesized δ-cadinene, whereas TgTPS2 produced ten distinct terpenoids. However, cultivation of the TgTPS2-expressing yeast in pH-maintained conditions (pH 6–7) yielded one major oxygenated sesquiterpenoid, suggesting that formation of multiple terpenoids was caused by acidity. The major terpene product from TgTPS2 was identified as 6β-hydroxygermacra-1(10),4-diene (kunzeaol) by mass-fragmentation pattern, retention index, the nature of its acid-induced degradation and NMR. Also, recombinant TgTPS2 efficiently catalysed the synthesis of kunzeaol in vitro from farnesyl diphosphate with a Km of 2.6 μM and a kcat of 0.03 s−1. The present paper is the first report of a kunzeaol synthase, and a mechanism for the transformation of kunzeaol into the thapsigargin backbone is proposed.
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20
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Pathogenic role of store-operated and receptor-operated ca(2+) channels in pulmonary arterial hypertension. JOURNAL OF SIGNAL TRANSDUCTION 2012; 2012:951497. [PMID: 23056939 PMCID: PMC3465915 DOI: 10.1155/2012/951497] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 07/12/2012] [Accepted: 07/16/2012] [Indexed: 12/31/2022]
Abstract
Pulmonary circulation is an important circulatory system in which the body brings in oxygen. Pulmonary arterial hypertension (PAH) is a progressive and fatal disease that predominantly affects women. Sustained pulmonary vasoconstriction, excessive pulmonary vascular remodeling, in situ thrombosis, and increased pulmonary vascular stiffness are the major causes for the elevated pulmonary vascular resistance (PVR) in patients with PAH. The elevated PVR causes an increase in afterload in the right ventricle, leading to right ventricular hypertrophy, right heart failure, and eventually death. Understanding the pathogenic mechanisms of PAH is important for developing more effective therapeutic approach for the disease. An increase in cytosolic free Ca2+ concentration ([Ca2+]cyt) in pulmonary arterial smooth muscle cells (PASMC) is a major trigger for pulmonary vasoconstriction and an important stimulus for PASMC migration and proliferation which lead to pulmonary vascular wall thickening and remodeling. It is thus pertinent to define the pathogenic role of Ca2+ signaling in pulmonary vasoconstriction and PASMC proliferation to develop new therapies for PAH. [Ca2+]cyt in PASMC is increased by Ca2+ influx through Ca2+ channels in the plasma membrane and by Ca2+ release or mobilization from the intracellular stores, such as sarcoplasmic reticulum (SR) or endoplasmic reticulum (ER). There are two Ca2+ entry pathways, voltage-dependent Ca2+ influx through voltage-dependent Ca2+ channels (VDCC) and voltage-independent Ca2+ influx through store-operated Ca2+ channels (SOC) and receptor-operated Ca2+ channels (ROC). This paper will focus on the potential role of VDCC, SOC, and ROC in the development and progression of sustained pulmonary vasoconstriction and excessive pulmonary vascular remodeling in PAH.
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21
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Madsen CP, Klausen TK, Fabian A, Hansen BJ, Pedersen SF, Hoffmann EK. On the role of TRPC1 in control of Ca2+ influx, cell volume, and cell cycle. Am J Physiol Cell Physiol 2012; 303:C625-34. [PMID: 22744003 DOI: 10.1152/ajpcell.00287.2011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ca(+) signaling plays a crucial role in control of cell cycle progression, but the understanding of the dynamics of Ca(2+) influx and release of Ca(2+) from intracellular stores during the cell cycle is far from complete. The aim of the present study was to investigate the role of the free extracellular Ca(2+) concentration ([Ca(2+)](o)) in cell proliferation, the pattern of changes in the free intracellular Ca(2+) concentration ([Ca(2+)](i)) during cell cycle progression, and the role of the transient receptor potential (TRP)C1 in these changes as well as in cell cycle progression and cell volume regulation. In Ehrlich Lettré Ascites (ELA) cells, [Ca(2+)](i) decreased significantly, and the thapsigargin-releasable Ca(2+) pool in the intracellular stores increased in G(1) as compared with G(0). Store-depletion-operated Ca(2+) entry (SOCE) and TRPC1 protein expression level were both higher in G(1) than in G(0) and S phase, in parallel with a more effective volume regulation after swelling [regulatory volume decrease (RVD)] in G(1) as compared with S phase. Furthermore, reduction of [Ca(2+)](o), as well as two unspecific SOCE inhibitors, 2-APB (2-aminoethyldiphenyl borinate) and SKF96365 (1-(β-[3-(4-methoxy-phenyl)propoxyl-4-methoxyphenethyl)1H-imidazole-hydrochloride), inhibited ELA cell proliferation. Finally, Madin-Darby canine kidney cells in which TRPC1 was stably silenced [TRPC1 knockdown (TRPC1-KD) MDCK] exhibited reduced SOCE, slower RVD, and reduced cell proliferation compared with mock controls. In conclusion, in ELA cells, SOCE and TRPC1 both seem to be upregulated in G(1) as compared with S phase, concomitant with an increased rate of RVD. Furthermore, TRPC1-KD MDCK cells exhibit decreased SOCE, decreased RVD, and decreased proliferation, suggesting that, at least in certain cell types, TRPC1 is regulated during cell cycle progression and is involved in SOCE, RVD, and cell proliferation.
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Affiliation(s)
- C P Madsen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
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22
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Kuhr FK, Smith KA, Song MY, Levitan I, Yuan JXJ. New mechanisms of pulmonary arterial hypertension: role of Ca²⁺ signaling. Am J Physiol Heart Circ Physiol 2012; 302:H1546-62. [PMID: 22245772 DOI: 10.1152/ajpheart.00944.2011] [Citation(s) in RCA: 145] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Pulmonary arterial hypertension (PAH) is a severe and progressive disease that usually culminates in right heart failure and death if left untreated. Although there have been substantial improvements in our understanding and significant advances in the management of this disease, there is a grim prognosis for patients in the advanced stages of PAH. A major cause of PAH is increased pulmonary vascular resistance, which results from sustained vasoconstriction, excessive pulmonary vascular remodeling, in situ thrombosis, and increased pulmonary vascular stiffness. In addition to other signal transduction pathways, Ca(2+) signaling in pulmonary artery smooth muscle cells (PASMCs) plays a central role in the development and progression of PAH because of its involvement in both vasoconstriction, through its pivotal effect of PASMC contraction, and vascular remodeling, through its stimulatory effect on PASMC proliferation. Altered expression, function, and regulation of ion channels and transporters in PASMCs contribute to an increased cytosolic Ca(2+) concentration and enhanced Ca(2+) signaling in patients with PAH. This review will focus on the potential pathogenic role of Ca(2+) mobilization, regulation, and signaling in the development and progression of PAH.
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Affiliation(s)
- Frank K Kuhr
- Section of Pulmonary, Critical Care, Sleep, and Allergy, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, USA
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23
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Kim EJ, Kim DK, Kim SH, Lee KM, Park HS, Kim SH. Alteration of Ryanodine-receptors in Cultured Rat Aortic Smooth Muscle Cells. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2011; 15:431-6. [PMID: 22359482 PMCID: PMC3282232 DOI: 10.4196/kjpp.2011.15.6.431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 11/25/2011] [Accepted: 11/25/2011] [Indexed: 12/02/2022]
Abstract
Vascular smooth muscle cells can obtain a proliferative function in environments such as atherosclerosis in vivo or primary culture in vitro. Proliferation of vascular smooth muscle cells is accompanied by changes in ryanodine receptors (RyRs). In several studies, the cytosolic Ca2+ response to caffeine is decreased during smooth muscle cell culture. Although caffeine is commonly used to investigate RyR function because it is difficult to measure Ca2+ release from the sarcoplasmic reticulum (SR) directly, caffeine has additional off-target effects, including blocking inositol trisphosphate receptors and store-operated Ca2+ entry. Using freshly dissociated rat aortic smooth muscle cells (RASMCs) and cultured RASMCs, we sought to provide direct evidence for the operation of RyRs through the Ca2+- induced Ca2+-release pathway by directly measuring Ca2+ release from SR in permeabilized cells. An additional goal was to elucidate alterations of RyRs that occurred during culture. Perfusion of permeabilized, freshly dissociated RASMCs with Ca2+ stimulated Ca2+ release from the SR. Caffeine and ryanodine also induced Ca2+ release from the SR in dissociated RASMCs. In contrast, ryanodine, caffeine and Ca2+ failed to trigger Ca2+ release in cultured RASMCs. These results are consistent with results obtained by immunocytochemistry, which showed that RyRs were expressed in dissociated RASMCs, but not in cultured RASMCs. This study is the first to demonstrate Ca2+ release from the SR by cytosolic Ca2+ elevation in vascular smooth muscle cells, and also supports previous studies on the alterations of RyRs in vascular smooth muscle cells associated with culture.
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Affiliation(s)
- Eun Ji Kim
- Department of Physiology, College of Medicine, Konyang University, Daejeon 302-718, Korea
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Lin YL, Lin RJ, Shen KP, Dai ZK, Chen IJ, Wu JR, Wu BN. Baicalein, isolated from Scutellaria baicalensis, protects against endothelin-1-induced pulmonary artery smooth muscle cell proliferation via inhibition of TRPC1 channel expression. JOURNAL OF ETHNOPHARMACOLOGY 2011; 138:373-381. [PMID: 21963569 DOI: 10.1016/j.jep.2011.09.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 09/14/2011] [Accepted: 09/15/2011] [Indexed: 05/31/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE We investigated the antiproliferative effects of baicalein, isolated from Scutellaria baicalensis (Huang-qin), on ET-1-mediated pulmonary artery smooth muscle cells (PASMCs) proliferation and the mechanisms underlying these effects. MATERIALS AND METHODS Intrapulmonary artery smooth muscle cells were isolated and cultured from female Sprague-Dawley rats and used during passages 3-6. The proliferation of PASMCs was quantified by cell counting and XTT assay. The protein expression of TRPC1 and PKCα were determined by western blotting. The cell cycle pattern was assayed by flow cytometry. The intracellular calcium concentrations ([Ca(2+)](i)) were measured using the fluorescent indicator fura-2-AM and flow cytometry. RESULTS Baicalein (0.3-3 μM) inhibited PASMCs proliferation, promoted cell cycle progression, enhanced [Ca(2+)](i) levels, increased capacitative Ca(2+) entry (CCE), upregulated the canonical transient receptor potential 1 (TRPC1) channel and membrane protein kinase Cα (PKCα) expression induced by ET-1 (0.1 μM). The PKC activator PMA (1 μM) reversed the inhibitory effects of baicalein on ET-1-induced upregulation of TRPC1 expression and S phase accumulation, while the PKC inhibitor chelerythrine (1 μM) potentiated baicalein-mediated G(2)/M phase arrest and TRPC1 channel inhibition. CONCLUSION Our findings suggest that baicalein protects against ET-1-induced PASMCs proliferation via modulation of the PKC-mediated TRPC channel.
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Affiliation(s)
- Yi-Ling Lin
- Department of Pharmacology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
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Zhang J, Webb SE, Ma LH, Chan CM, Miller AL. Necessary role for intracellular Ca2+ transients in initiating the apical-basolateral thinning of enveloping layer cells during the early blastula period of zebrafish development. Dev Growth Differ 2011; 53:679-96. [PMID: 21671916 DOI: 10.1111/j.1440-169x.2011.01275.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
During the early blastula period of zebrafish embryos, the outermost blastomeres begin to undergo a significant thinning in the apical/basolateral dimension to form the first distinct cellular domain of the embryo, the enveloping layer (EVL). During this shape transformation, only the EVL-precursor cells generate a coincidental series of highly restricted Ca(2+) transients. To investigate the role of these localized Ca(2+) transients in this shape-change process, embryos were treated with a Ca(2+) chelator (5,5'-difluoro BAPTA AM; DFB), or the Ca(2+) ionophore (A23187), to downregulate and upregulate the transients, respectively, while the shape-change of the forming EVL cells was measured. DFB was shown to significantly slow, and A23187 to significantly facilitate the shape change of the forming EVL cells. In addition, to investigate the possible involvement of the phosphoinositide and Wnt/Ca(2+) signaling pathways in the Ca(2+) transient generation and/or shape-change processes, embryos were treated with antagonists (thapsigargin, 2-APB and U73122) or an agonist (Wnt-5A) of these pathways. Wnt-5A upregulated the EVL-restricted Ca(2+) transients and facilitated the change in shape of the EVL cells, while 2-APB downregulated the Ca(2+) transients and significantly slowed the cell shape-change process. Furthermore, thapsigargin and U73122 also both inhibited the EVL cell shape-change. We hypothesize, therefore, that the highly localized and coincidental Ca(2+) transients play a necessary role in initiating the shape-change of the EVL cells.
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Affiliation(s)
- Jiao Zhang
- Division of Life Science, and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
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Chang AY, Sliwoski J, Butler S, Hearn G, Lassmann J, Chacko S, Canning DA, Zderic SA. Calcineurin mediates bladder wall remodeling secondary to partial outlet obstruction. Am J Physiol Renal Physiol 2011; 301:F813-22. [PMID: 21775483 DOI: 10.1152/ajprenal.00586.2010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We hypothesized that the calcineurin-nuclear factor of activated T-cells (NFAT) pathway is activated following partial bladder outlet obstruction (pBOO), which would allow for pharmacologic treatment to prevent the ensuing bladder wall hypertrophy. Using a model of pBOO in male mice, we were able to demonstrate increased nuclear importation of the transcription factors NFAT and myocyte enhanching factor 2 both of which are under control of calcineurin in both the whole bladder wall as well as the urothelium. We further confirmed that this pathway was activated using transgenic mice containing an NFAT-luciferase reporter construct. Mice were randomized following pBOO to treatment with or without cyclosporine A (CsA), a known inhibitor of calcineurin. The bladder-to-body mass ratio (mg bladder wt/g body wt) of 0.95 ± 0.03 in shams increased to 3.1 ± 0.35 following pBOO, and it dropped back to 1.7 ± 0.22 in the CsA+ group (P < 0.001). Luciferase values (RLU) of 1,130 ± 133 in shams increased to 2,010 ± 474 following pBOO and were suppressed to 562 ± 177 in the CsA+ group (P < 0.05). The myosin heavy chain mRNA (A/B) isoform ratio of 0.07 ± 0.03 in shams increased to 1.04 ± 0.19 following pBOO but it diminished to 0.24 ± 0.1 in the CsA+ group (P < 0.001). In vitro whole organ physiology studies demonstrated improved responses in those bladders from mice treated with CsA. The mRNAs for all four known calcineurin-responsive NFAT isoforms are expressed in the bladder wall, although NFATc(3) and NFATc(4) predominate. Both NFATc3 and NFATc4 are expressed in urothelial as well as smooth muscle cells. We conclude that pBOO activates the calcineurin-NFAT pathway and that CsA treatment decreased bladder hypertrophy, shifted the pattern of myosin isoform mRNA expression back toward that seen in normal controls, and resulted in improved in vitro whole organ performance.
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Affiliation(s)
- Andy Y Chang
- John W. Duckett Jr. Center for Pediatric Urology at The Children's Hospital of Philadelphia 19104, USA
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Banas A, Banas K, Kwiatek WM, Gajda M, Pawlicki B, Cichocki T. Neoplastic disorders of prostate glands in the light of synchrotron radiation and multivariate statistical analysis. J Biol Inorg Chem 2011; 16:1187-96. [PMID: 21706339 PMCID: PMC3221053 DOI: 10.1007/s00775-011-0807-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 06/12/2011] [Indexed: 11/28/2022]
Abstract
The prostate gland is the most common site of neoplastic disorders in men. The pathogenesis of inflammatory cells, prostatic intraepithelial neoplasia (PIN) lesions, and prostate cancer is still under investigation. Inflammatory cells by producing free radicals are considered as major and universal contributors to cancerogenesis. PIN is regarded as a precursor lesion to prostate cancer or a marker signaling the vulnerability of the epithelium to neoplastic transformation [1]. Differentiation markers that are frequently changed in early invasive carcinoma are also changed in PIN lesions. In this study, prostate tissue samples obtained during surgical operation and classified as various disease states (inflammation, PIN lesions, and cancer) were examined. The samples were measured by means of microbeam synchrotron-radiation-induced X-ray emission (micro-SRIXE). Special attention was paid to examine the relationship between the earlier-mentioned disorders and changes in relative concentrations of S, K, Ca, Fe, Cu, and Zn. Applying the image-processing program ImageJ enabled us to select the areas of interest from two-dimensional maps of various prostate samples according to the histopathologist's evaluation. Detailed analysis of micro-SRIXE spectra based on multivariate methods shows significant differences between elemental concentrations in inflammatory cells, PIN lesions, and cancerous tissues, which confirms that this method can be used to distinguish various pathological states in prostate tissues. Information obtained in this way may provide better understanding of the biochemistry of unhealthy prostate tissues, thus opening the way to find new medicines/treatments to prevent or slow down some harmful intracellular processes.
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Affiliation(s)
- A Banas
- Institute of Nuclear Physics, Polish Academy of Sciences, Kraków, Poland
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Sung JY, Choi HC. Nifedipine inhibits vascular smooth muscle cell proliferation and reactive oxygen species production through AMP-activated protein kinase signaling pathway. Vascul Pharmacol 2011; 56:1-8. [PMID: 21708289 DOI: 10.1016/j.vph.2011.06.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 05/24/2011] [Accepted: 06/13/2011] [Indexed: 12/16/2022]
Abstract
The dihydropyridine calcium channel blocker nifedipine induces specific pharmacological effects by binding to L-type calcium channels, which results in a reduced calcium influx in vascular smooth muscle cells (VSMCs) and is currently employed in antihypertensive drug. Dihydropyridine calcium channel blocker is reported to reduce oxidative stress and exhibits anti-proliferative effect in VSMCs. VSMCs are useful in the study of atherosclerosis because they show cell proliferation and reactive oxygen species (ROS) production with growth factor. To determine the mechanisms involved in these effects, we investigated the influence of nifedipine-induced AMP-activated protein kinase (AMPK) activation on VSMC proliferation and ROS production by using rat aortic VSMCs in vitro and in vivo. Nifedipine induced phosphorylation of AMPK in a dose-and time-dependent manner, and inhibited rat VSMC proliferation and ROS production following stimulation with 15% fetal bovine serum (FBS). Nifedipine also blocked the FBS-stimulated cell cycle progression through the G0/G1 arrest. Compound C, a specific inhibitor of AMPK, or AMPK siRNA reduced the nifedipine-mediated inhibition of VSMC proliferation. As an upstream kinase, LKB1 is required for nifedipine-induced AMPK activation in VSMCs. 7 days oral administration of 1 mg/kg nifedipine resulted in activation of LKB1 and AMPK in vivo. These data suggest that nifedipine suppress the VSMC proliferation and ROS production via activating LKB1-AMPK pathway.
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Affiliation(s)
- Jin Young Sung
- Department of Pharmacology, Aging-associated Vascular Disease Research Center, College of Medicine, Yeungnam University, Daegu 705-717, Republic of Korea
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Firth AL, Remillard CV, Platoshyn O, Fantozzi I, Ko EA, Yuan JXJ. Functional ion channels in human pulmonary artery smooth muscle cells: Voltage-dependent cation channels. Pulm Circ 2011; 1:48-71. [PMID: 21927714 PMCID: PMC3173772 DOI: 10.4103/2045-8932.78103] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The activity of voltage-gated ion channels is critical for the maintenance of cellular membrane potential and generation of action potentials. In turn, membrane potential regulates cellular ion homeostasis, triggering the opening and closing of ion channels in the plasma membrane and, thus, enabling ion transport across the membrane. Such transmembrane ion fluxes are important for excitation–contraction coupling in pulmonary artery smooth muscle cells (PASMC). Families of voltage-dependent cation channels known to be present in PASMC include voltage-gated K+ (Kv) channels, voltage-dependent Ca2+-activated K+ (Kca) channels, L- and T- type voltage-dependent Ca2+ channels, voltage-gated Na+ channels and voltage-gated proton channels. When cells are dialyzed with Ca2+-free K+- solutions, depolarization elicits four components of 4-aminopyridine (4-AP)-sensitive Kvcurrents based on the kinetics of current activation and inactivation. In cell-attached membrane patches, depolarization elicits a wide range of single-channel K+ currents, with conductances ranging between 6 and 290 pS. Macroscopic 4-AP-sensitive Kv currents and iberiotoxin-sensitive Kca currents are also observed. Transcripts of (a) two Na+ channel α-subunit genes (SCN5A and SCN6A), (b) six Ca2+ channel α–subunit genes (α1A, α1B, α1X, α1D, α1Eand α1G) and many regulatory subunits (α2δ1, β1-4, and γ6), (c) 22 Kv channel α–subunit genes (Kv1.1 - Kv1.7, Kv1.10, Kv2.1, Kv3.1, Kv3.3, Kv3.4, Kv4.1, Kv4.2, Kv5.1, Kv 6.1-Kv6.3, Kv9.1, Kv9.3, Kv10.1 and Kv11.1) and three Kv channel β-subunit genes (Kvβ1-3) and (d) four Kca channel α–subunit genes (Sloα1 and SK2-SK4) and four Kca channel β-subunit genes (Kcaβ1-4) have been detected in PASMC. Tetrodotoxin-sensitive and rapidly inactivating Na+ currents have been recorded with properties similar to those in cardiac myocytes. In the presence of 20 mM external Ca2+, membrane depolarization from a holding potential of -100 mV elicits a rapidly inactivating T-type Ca2+ current, while depolarization from a holding potential of -70 mV elicits a slowly inactivating dihydropyridine-sensitive L-type Ca2+ current. This review will focus on describing the electrophysiological properties and molecular identities of these voltage-dependent cation channels in PASMC and their contribution to the regulation of pulmonary vascular function and its potential role in the pathogenesis of pulmonary vascular disease.
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Affiliation(s)
- Amy L Firth
- The Salk Institute for Biological Studies, La Jolla, California, USA
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Ni HM, Baty CJ, Li N, Ding WX, Gao W, Li M, Chen X, Ma J, Michalopoulos GK, Yin XM. Bid agonist regulates murine hepatocyte proliferation by controlling endoplasmic reticulum calcium homeostasis. Hepatology 2010; 52:338-48. [PMID: 20578150 PMCID: PMC2943424 DOI: 10.1002/hep.23672] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
UNLABELLED BH3-interacting domain death agonist (Bid), a BH3-only B cell lymphoma 2 family molecule, is generally known for its importance in activating the mitochondrial apoptosis pathway after death receptor engagement, particularly in hepatocytes. However, Bid also promotes hepatocyte proliferation during liver regeneration and carcinogenesis. This study was designed to examine the hypothesis that Bid regulates endoplasmic reticulum calcium concentration ([Ca(2+)](ER)) homeostasis to affect hepatocyte proliferation. We found that serum-stimulated hepatocyte proliferation was dependent on calcium, and the depletion of calcium with thapsigargin or ethylene glycol tetraacetic acid (EGTA) inhibited the proliferation. Subcellular fractionation showed that a portion of Bid was inserted into the endoplasmic reticulum (ER)-enriched membranes, and single-cell calcium imaging indicated that Bid was important for maintaining the [Ca(2+)](ER) level. Bid-deficient hepatocytes manifested delayed and reduced serum-stimulated proliferation, which was corrected by ionomycin or reconstitution of Bid, particularly an ER-targeted Bid. Finally, B cell lymphoma 2-associated X protein (Bax) could also be found in the ER-enriched membranes, and Bax deficiency caused the same proliferation defect. However, Bid/Bax double deletion in hepatocytes did not further augment the defect, which suggested that Bid and Bax worked by the same regulatory mechanism in [Ca(2+)](ER) control. CONCLUSION Bid regulates hepatocyte proliferation by positively affecting [Ca(2+)](ER) homeostasis, and this could be important for liver regeneration and carcinogenesis.
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Affiliation(s)
- Hong-Min Ni
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Catherine J. Baty
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Na Li
- Department of Physiology and Biophysics, UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ 08854
| | - Wen-Xing Ding
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Wentao Gao
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Min Li
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Xiaoyun Chen
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Jianjie Ma
- Department of Physiology and Biophysics, UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ 08854
| | | | - Xiao-Ming Yin
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
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Henderson K, Stella SL, Kobylewski S, Eckhert CD. Receptor activated Ca(2+) release is inhibited by boric acid in prostate cancer cells. PLoS One 2009; 4:e6009. [PMID: 19554099 PMCID: PMC2698284 DOI: 10.1371/journal.pone.0006009] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Accepted: 05/20/2009] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The global disparity in cancer incidence remains a major public health problem. We focused on prostate cancer since microscopic disease in men is common, but the incidence of clinical disease varies more than 100 fold worldwide. Ca(2+) signaling is a central regulator of cell proliferation, but has received little attention in cancer prevention. We and others have reported a strong dose-dependent reduction in the incidence of prostate and lung cancer within populations exposed to boron (B) in drinking water and food; and in tumor and cell proliferation in animal and cell culture models. METHODS/PRINCIPAL FINDINGS We examined the impact of B on Ca(2+) stores using cancer and non-cancer human prostate cell lines, Ca(2+) indicators Rhod-2 AM and Indo-1 AM and confocal microscopy. In DU-145 cells, inhibition of Ca(2+) release was apparent following treatment with Ringers containing RyR agonists cADPR, 4CmC or caffeine and respective levels of BA (50 microM), (1, 10 microM) or (10, 20, 50,150 microM). Less aggressive LNCaP cancer cells required 20 microM BA and the non-tumor cell line PWR1E required 150 microM BA to significantly inhibit caffeine stimulated Ca(2+) release. BA (10 microM) and the RyR antagonist dantroline (10 microM) were equivalent in their ability to inhibit ER Ca(2+) loss. Flow cytometry and confocal microscopy analysis showed exposure of DU-145 cells to 50 microM BA for 1 hr decreased stored [Ca(2+)] by 32%. CONCLUSION/SIGNIFICANCE We show B causes a dose dependent decrease of Ca(2+) release from ryanodine receptor sensitive stores. This occurred at BA concentrations present in blood of geographically disparate populations. Our results suggest higher BA blood levels lower the risk of prostate cancer by reducing intracellular Ca(2+) signals and storage.
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Affiliation(s)
- Kimberly Henderson
- Molecular Toxicology, School of Public Health, University of California Los Angeles, Los Angeles, California, United States of America
| | - Salvatore L. Stella
- Neurobiology, Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Sarah Kobylewski
- Molecular Toxicology, School of Public Health, University of California Los Angeles, Los Angeles, California, United States of America
| | - Curtis D. Eckhert
- Molecular Toxicology, School of Public Health, University of California Los Angeles, Los Angeles, California, United States of America
- Environmental Health Sciences, School of Public Health, University of California Los Angeles, Los Angeles, California, United States of America
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Begum G, Dube A, Joshi PG, Gupta PK, Joshi NB. Chlorin p6 preferentially localizes in endoplasmic reticulum and Golgi apparatus and inhibits Ca2+ release from intracellular store. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2009; 95:177-84. [DOI: 10.1016/j.jphotobiol.2009.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Revised: 02/28/2009] [Accepted: 03/05/2009] [Indexed: 12/28/2022]
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The role of store-operated Ca2+ channels in adrenocorticotropin release by rat pituitary cells. ACTA ACUST UNITED AC 2009; 156:57-64. [PMID: 19445971 DOI: 10.1016/j.regpep.2009.05.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2008] [Revised: 03/06/2009] [Accepted: 05/06/2009] [Indexed: 11/24/2022]
Abstract
In this study, we investigated the role of store-operated Ca2+ channels (SOCC) on ACTH release using microperifusion system. The SOCC blockers, SKF96365 and MRS1845, did not affect the ACTH response to single AVP stimulation. After the depletion of intracellular Ca2+ stores by treating with ionomycin, SOCC blockers reduced the initial spike phase of ACTH response to AVP, which is mediated by inositol 1,4,5-trisphosphate-induced intracellular Ca2+ release from the endoplasmic reticulum (ER). The sustained plateau phase of ACTH response, which is mediated by protein kinase C leading Ca2+ influx via L-type voltage-dependent Ca2+ channels, was not affected. Addition of L-type voltage-dependent Ca2+ channel blocker nimodipine with the SOCC blockers reduced both the initial spike and sustained phases of ACTH response to AVP. Even after ER Ca2+ depletion, the SOCC blockers did not affect the ACTH response to CRH, which is mediated by cAMP-dependent protein kinase A. Transient receptor potential (TRP) C channel is the strongest candidate for SOCC, and RT-PCR revealed that all types of TRPC homologue mRNA were expressed in rat anterior pituitary cells. In conclusion, the SOCC mediates the initial spike phase of ACTH response to AVP, possibly via ER Ca2+ store refilling to induce maximum response.
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Wang J, Jiang L, Gao X, Ding H, Wang Q, Cheng J, Gao R, Xiao H. Fenvalerate-induced Ca2+ transients via both intracellular and extracellular way in mouse GC-2spd (ts) cells. Toxicology 2009; 259:122-32. [DOI: 10.1016/j.tox.2009.02.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2008] [Revised: 02/19/2009] [Accepted: 02/19/2009] [Indexed: 11/28/2022]
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Lam CMC, Yeung PKK, Lee HC, Wong JTY. Cyclic ADP-ribose links metabolism to multiple fission in the dinoflagellate Crypthecodinium cohnii. Cell Calcium 2009; 45:346-57. [PMID: 19201464 DOI: 10.1016/j.ceca.2008.12.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 11/27/2008] [Accepted: 12/31/2008] [Indexed: 12/19/2022]
Abstract
Cellular metabolism is required for cell proliferation. However, the way in which metabolic signals are conveyed to cell cycle decisions is unclear. Cyclic ADP-ribose (cADPR), the NAD(+) metabolite, mobilizes calcium from calcium stores in many cells. We found that dinoflagellate cells with higher metabolic rate underwent multiple fission (MF), a division mode in which cells can exceed twice their sizes at G1. A temperature shift-down experiment suggested that MF involves a commitment point at late G1. In fast-growing cells, cADPR level peaked in G(1) and increased with increasing concentrations of glucose in the medium. Addition of glycolytic poison iodoacetate inhibited cell growth, reduced cADPR levels as well as the commitment of cell cycles in fast-growing cells. Commitment of MF cell cycles was induced by a cell permeant cADPR agonist, but blocked by a specific antagonist of cADPR-induced Ca(2+) release. Our results establish cADPR as a link between cellular metabolism and cell cycle control.
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Affiliation(s)
- Connie M C Lam
- Department of Biology, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
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Aley PK, Wilkinson JA, Bauer CC, Boyle JP, Porter KE, Peers C. Hypoxic remodelling of Ca(2+) signalling in proliferating human arterial smooth muscle. Mol Cell Biochem 2008; 318:101-8. [PMID: 18636316 DOI: 10.1007/s11010-008-9861-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2008] [Accepted: 06/25/2008] [Indexed: 11/29/2022]
Abstract
Ca(2+) homeostasis in proliferating smooth muscle (SM) cells strongly influences neointima formation, which can cause failure of coronary artery bypass surgery. During surgical procedures and subsequent revascularization, SM cells are also exposed to a period of hypoxia. Problems with bypass surgery in general involve neointima formation which is in turn dependent on SM proliferation and migration. Here, we have directly monitored [Ca(2+)](i) fluorimetrically in proliferating internal mammary artery (IMA) SM cells, and investigated how this is modulated by chronic hypoxia (CH; 24 h, 2.5% O(2)). IMA is the most successful replacement conduit vessel in bypass grafts. Basal [Ca(2+)](i) was unaffected by CH, but removal of extracellular Ca(2+) evoked far smaller reductions in [Ca(2+)](i) than were seen in normoxic cells. Voltage-gated Ca(2+) entry was suppressed in CH cells, and this was attributable to activation of the transcriptional regulator, hypoxia inducible factor. Furthermore, the relative contributions to voltage-gated Ca(2+) entry of L- and T-type Ca(2+) channels was markedly altered, with T-type channels becoming functionally more important in CH cells. Agonist-evoked mobilization of Ca(2+) from intracellular stores was not affected by CH, whilst subsequent capacitative Ca(2+) entry was modestly suppressed. Our data provide novel observations of the remodelling of Ca(2+) homeostasis by CH in IMASM cells which may contribute to their superior patency as coronary bypass grafts.
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Affiliation(s)
- Parvinder K Aley
- Division of Cardiovascular and Neuronal Remodelling, Leeds Institute of Genetics, Health & Therapeutics, University of Leeds, Level 10, Worsley Building, Leeds, LS2 9JT, UK
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Berra-Romani R, Mazzocco-Spezzia A, Pulina MV, Golovina VA. Ca2+ handling is altered when arterial myocytes progress from a contractile to a proliferative phenotype in culture. Am J Physiol Cell Physiol 2008; 295:C779-90. [PMID: 18596214 DOI: 10.1152/ajpcell.00173.2008] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Phenotypic modulation of vascular myocytes is important for vascular development and adaptation. A characteristic feature of this process is alteration in intracellular Ca(2+) handling, which is not completely understood. We studied mechanisms involved in functional changes of inositol 1,4,5-trisphosphate (IP(3))- and ryanodine (Ry)-sensitive Ca(2+) stores, store-operated Ca(2+) entry (SOCE), and receptor-operated Ca(2+) entry (ROCE) associated with arterial myocyte modulation from a contractile to a proliferative phenotype in culture. Proliferating, cultured myocytes from rat mesenteric artery have elevated resting cytosolic Ca(2+) levels and increased IP(3)-sensitive Ca(2+) store content. ATP- and cyclopiazonic acid [CPA; a sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) inhibitor]-induced Ca(2+) transients in Ca(2+)-free medium are significantly larger in proliferating arterial smooth muscle cells (ASMCs) than in freshly dissociated myocytes, whereas caffeine (Caf)-induced Ca(2+) release is much smaller. Moreover, the Caf/Ry-sensitive store gradually loses sensitivity to Caf activation during cell culture. These changes can be explained by increased expression of all three IP(3) receptors and a switch from Ry receptor type II to type III expression during proliferation. SOCE, activated by depletion of the IP(3)/CPA-sensitive store, is greatly increased in proliferating ASMCs. Augmented SOCE and ROCE (activated by the diacylglycerol analog 1-oleoyl-2-acetyl-sn-glycerol) in proliferating myocytes can be attributed to upregulated expression of, respectively, transient receptor potential proteins TRPC1/4/5 and TRPC3/6. Moreover, stromal interacting molecule 1 (STIM1) and Orai proteins are upregulated in proliferating cells. Increased expression of IP(3) receptors, SERCA2b, TRPCs, Orai(s), and STIM1 in proliferating ASMCs suggests that these proteins play a critical role in an altered Ca(2+) handling that occurs during vascular growth and remodeling.
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Affiliation(s)
- Roberto Berra-Romani
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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Wang X, Pluznick JL, Settles DC, Sansom SC. Association of VASP with TRPC4 in PKG-mediated inhibition of the store-operated calcium response in mesangial cells. Am J Physiol Renal Physiol 2007; 293:F1768-76. [PMID: 17913834 DOI: 10.1152/ajprenal.00365.2007] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
We tested the hypotheses that the NO-cGMP-PKG pathway mediates inhibition of the store-operated cation channel (SOC) in human glomerular mesangial cells (HMC) and that TRPC4, a molecular component of SOC in HMC, is associated with PKG-phosphorylated vasodilator-stimulated phosphoprotein (VASP). Using fura 2 ratiometry, we measured intracellular Ca(2+) concentration [Ca(2+)](i) to determine whether sodium nitroprusside (SNP), an NO donor, and 8-Br-cGMP affected SOC-TRPC4 via PKG. We found that the SOC response in HMC was attenuated in the presence of 100 microM SNP, an NO donor, or 100 microM 8-Br-cGMP. Addition of DT-3 (2.5 microM), a specific PKG-1alpha inhibitor, reversed the effects of 8-Br-cGMP on the SOC response. Application of 100 microM cAMP did not significantly inhibit the SOC response. RT-PCR and Western blotting revealed PKG-1alpha transcript and protein in HMC. Immunocytochemical analysis localized PKG-1alpha to the cytoplasm and plasma membrane of HMC. Previous studies have shown that PKG-mediated phosphorylation of VASP attenuates cellular Ca(2+) entry, resulting in altered growth and proliferation. Therefore, we used Western blotting and immunocytochemistry to determine whether PKG-phosphorylated VASP associates with TRPC4. Western blot analysis revealed that 8-Br-cGMP enhanced the phosphorylation of VASP at serine 239 (Ser239), a known PKG phosphorylation site, in HMC within 5 min. Coimmunoprecipitation and coimmunostaining showed that P-Ser239-VASP associated with TRPC4. However, VASP that was unphosphorylated at Ser239 was not associated with TRPC4. These results indicate that VASP has a role in the NO/PKG-1alpha-mediated inhibition of the TRPC4-SOC response in HMC.
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Andrews SP, Ball M, Wierschem F, Cleator E, Oliver S, Högenauer K, Simic O, Antonello A, Hünger U, Smith MD, Ley SV. Total Synthesis of Five Thapsigargins: Guaianolide Natural Products Exhibiting Sub-Nanomolar SERCA Inhibition. Chemistry 2007; 13:5688-712. [PMID: 17508363 DOI: 10.1002/chem.200700302] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Herein we describe the total synthesis of five guaianolide natural products: thapsigargin, thapsivillosin C, thapsivillosin F, trilobolide and nortrilobolide. Prodrug derivatives of thapsigargin have shown selective in vivo cytotoxicity against prostate tumours and the need for further investigation of this phenomenon highlights the importance of these total syntheses. The first absolute stereochemical assignment of thapsivillosin C is also delineated.
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Affiliation(s)
- Stephen P Andrews
- University Chemical Laboratory, Lensifield Road, Cambridge, CB2 1EW, UK
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40
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Martins RAP, Pearson RA. Control of cell proliferation by neurotransmitters in the developing vertebrate retina. Brain Res 2007; 1192:37-60. [PMID: 17597590 DOI: 10.1016/j.brainres.2007.04.076] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Revised: 04/04/2007] [Accepted: 04/20/2007] [Indexed: 01/24/2023]
Abstract
In the developing vertebrate retina, precise coordination of retinal progenitor cell proliferation and cell-cycle exit is essential for the formation of a functionally mature retina. Unregulated or disrupted cell proliferation may lead to dysplasia, retinal degeneration or retinoblastoma. Both cell-intrinsic and -extrinsic factors regulate the proliferation of progenitor cells during CNS development. There is now growing evidence that in the developing vertebrate retina, both slow and fast neurotransmitter systems modulate the proliferation of retinal progenitor cells. Classic neurotransmitters, such as GABA (gamma-amino butyric acid), glycine, glutamate, ACh (acetylcholine) and ATP (adenosine triphosphate) are released, via vesicular or non-vesicular mechanisms, into the immature retinal environment. Furthermore, these neurotransmitters signal through functional receptors even before synapses are formed. Recent evidence indicates that the activation of purinergic and muscarinic receptors may regulate the cell-cycle machinery and consequently the expansion of the retinal progenitor pool. Interestingly, GABA and glutamate appear to have opposing roles, inducing retinal progenitor cell-cycle exit. In this review, we present recent findings that begin to elucidate the roles of neurotransmitters as regulators of progenitor cell proliferation at early stages of retinal development. These studies also raise several new questions, including how these neurotransmitters regulate specific cell-cycle pathways and the mechanisms by which retinal progenitor cells integrate the signals from neurotransmitters and other exogenous factors during vertebrate retina development.
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Affiliation(s)
- Rodrigo A P Martins
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, MS323, Memphis, TN 38105, USA.
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Andrews SP, Tait MM, Ball M, Ley SV. Design and total synthesis of unnatural analogues of the sub-nanomolar SERCA inhibitor thapsigargin. Org Biomol Chem 2007; 5:1427-36. [PMID: 17464412 DOI: 10.1039/b702481a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Thapsigargin is a densely oxygenated guaianolide which displays potent sarco/endoplasmic reticulum Ca(2+) ATPase (SERCA) binding affinities. The total syntheses of designed unnatural analogues of this important natural product are described. This article constitutes the chemical synthesis behind an ongoing project. Rational modifications have been made to the lactone region of thapsigargin in order to obtain derivatives for future structure-activity relationship studies.
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Affiliation(s)
- Stephen P Andrews
- University Chemical Laboratory, Lensfield Road, Cambridge, CB2 1EW, UK
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42
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Afroze T, Sadi AM, Momen MA, Gu S, Heximer S, Husain M. c-Myb-dependent inositol 1,4,5-trisphosphate receptor type-1 expression in vascular smooth muscle cells. Arterioscler Thromb Vasc Biol 2007; 27:1305-11. [PMID: 17363689 DOI: 10.1161/atvbaha.107.142059] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The IP3 receptor-1 (IP3R1) mediates Ca2+ signals critical to vascular smooth muscle cell (VSMC) proliferation. The cell cycle-associated transcription factor c-Myb increases Ca2+ at the G1/S transition. Here we show the mechanism through which c-Myb regulates expression of IP3R1. METHODS & RESULTS Ribonuclease protection confirmed transcriptional start (TS), and qRT-PCR revealed a 6-fold increase in IP3R1 mRNA as immortalized VSMC progress from G0 to G1/S. A c-Myb neutralizing antibody decreased IP3R1 mRNA expression 3-fold, and abolished the 3.4-fold increase in IP3R1 protein observed at G1/S. Primary aortic VSMCs in culture and proliferating carotid VSMCs in vivo showed similar regulation of IP3R1 mRNA and protein. Sequence analysis of a 3.1-Kb mouse IP3R1 promoter revealed 17 putative c-Myb binding sites. Reporter assays demonstrated a 2-fold increase in promoter activity in G1/S- versus G0-synchronized VSMCs, which was abolished by functional c-Myb knockdown or deletion of promoter sequences upstream and downstream of TS. Point mutations in Myb sites-13 or -15 significantly blunted G1/S-specific promoter induction in both immortalized and primary VSMCs. Gel shift and ChIP confirmed binding of c-Myb to sites-13 and -15 in G1/S stage VSMCs. CONCLUSION c-Myb regulates cell cycle-associated IP3R1 transcription in VSMCs via specific highly conserved Myb-binding sites in the IP3R1 promoter.
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MESH Headings
- Animals
- Calcium/metabolism
- Calcium Channels/genetics
- Calcium Channels/metabolism
- Carotid Arteries/surgery
- Carotid Artery Diseases/genetics
- Carotid Artery Diseases/metabolism
- Carotid Artery Diseases/physiopathology
- Cell Cycle/physiology
- Cell Line
- Cell Proliferation
- Chromatin Immunoprecipitation
- Conserved Sequence
- DNA/metabolism
- Disease Models, Animal
- Electrophoretic Mobility Shift Assay
- Genes, Reporter
- Inositol 1,4,5-Trisphosphate Receptors
- Luciferases
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/metabolism
- Mice
- Mice, Inbred C57BL
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Mutation
- Myocytes, Smooth Muscle/metabolism
- Promoter Regions, Genetic
- Proto-Oncogene Proteins c-myb/metabolism
- RNA, Messenger/metabolism
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Sequence Analysis, DNA
- Transcription, Genetic
- Transfection
- Up-Regulation
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Affiliation(s)
- Talat Afroze
- Division of Cell and Molecular Biology, Toronto General Hospital Research Institute, Toronto, Ontario, Canada
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Hiroishi G, Murata T, Ishibashi T. Effect of thiazolidinedione on the proliferation of bovine retinal endothelial cells stimulated by vascular endothelial cell growth factor. Jpn J Ophthalmol 2007; 51:21-6. [PMID: 17295136 DOI: 10.1007/s10384-006-0385-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2005] [Accepted: 05/11/2006] [Indexed: 11/26/2022]
Abstract
PURPOSE To investigate the effect of troglitazone, an antidiabetic drug, on the cytosolic Ca(2+) concentrations ([Ca(2+)]i) and the cell cycles of bovine retinal endothelial cells (RECs) stimulated with vascular endothelial growth factor (VEGF). METHODS The changes in [Ca(2+)]i were monitored using microfluorometry with Fura-2. The phase of the cell cycle was examined by an immunocytochemical analysis using monoclonal antibodies against cell cycle-specific nuclear antigens. RESULTS In the presence of extracellular Ca(2+), VEGF-induced transient [Ca(2+)]i elevation followed by continuous steady-state elevation resulted in cell cycle progression in RECs. The removal of extracellular Ca(2+) inhibited the continuous component, but transient [Ca(2+)]i elevation was still observed. These results are compatible with the hypothesis that a continuous steady-state elevation of [Ca(2+)]i may be mediated mainly through the influx of extracellular Ca(2+). Pretreatment with 10 microM troglitazone prevented the transient and continuous steady-state elevation of [Ca(2+)]i, resulting in an inhibition of the cell cycle in RECs stimulated with VEGF. CONCLUSIONS These data suggest that troglitazone inhibits VEGF-induced cell cycle progression through the inhibition of [Ca(2+)]i in RECs.
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Affiliation(s)
- Goro Hiroishi
- Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
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Crépin A, Bidaux G, Vanden-Abeele F, Dewailly E, Goffin V, Prevarskaya N, Slomianny C. Prolactin stimulates prostate cell proliferation by increasing endoplasmic reticulum content due to SERCA 2b over-expression. Biochem J 2007; 401:49-55. [PMID: 16965263 PMCID: PMC1698681 DOI: 10.1042/bj20060870] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Prolactin (PRL) has been shown to be involved in the differentiation and proliferation of numerous tissues, including the prostate gland. Moreover, variations in [Ca2+]ER (calcium concentration within the endoplasmic reticulum) may play a role in cell growth. However, few studies have focused on the regulation of calcium homoeostasis by prolactin. The present study evaluates the regulation of calcium pools as well as the possible role of [Ca2+]ER variations as a signal for growth modulation by PRL. We show that PRL stimulates the proliferation of normal SV40 immortalized epithelial prostate (PNT1A) cells with a maximum effect at a dose of 100 ng/ml. We also show that 100 ng/ml PRL increases the [Ca2+]ER when measured either by indirect quantification with Fura-2AM after application of 1 mM thapsigargin or by direct quantification with Mag-Fura-2AM within the endoplas-mic reticulum. Western blot analysis shows that the SERCA 2b (sarcoendoplasmic calcium ATPase 2b) is over-expressed in PNT1A cells treated with 100 ng/ml PRL for 24 h. A small inter-fering RNA SERCA 2a/b, used to down-regulate endogenous SERCA 2b expression, reduced both PNT1A cell proliferation and [Ca2+]ER. We thus identify [Ca2+]ER and SERCA 2b as protagonists in PRL-induced proliferation.
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Affiliation(s)
- Alexandre Crépin
- *Inserm, U800, Laboratoire de Physiologie Cellulaire, Équipe Labellisée par la Ligue Contre le Cancer, Villeneuve d'Ascq, F-59655 France; Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, F-59655 France
| | - Gabriel Bidaux
- *Inserm, U800, Laboratoire de Physiologie Cellulaire, Équipe Labellisée par la Ligue Contre le Cancer, Villeneuve d'Ascq, F-59655 France; Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, F-59655 France
| | - Fabien Vanden-Abeele
- *Inserm, U800, Laboratoire de Physiologie Cellulaire, Équipe Labellisée par la Ligue Contre le Cancer, Villeneuve d'Ascq, F-59655 France; Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, F-59655 France
| | - Etienne Dewailly
- *Inserm, U800, Laboratoire de Physiologie Cellulaire, Équipe Labellisée par la Ligue Contre le Cancer, Villeneuve d'Ascq, F-59655 France; Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, F-59655 France
| | - Vincent Goffin
- †Inserm, U808, Faculté de Médecine Necker, Paris, F-75730, France; Université de Paris Descartes, Paris, F-75730, France
| | - Natalia Prevarskaya
- *Inserm, U800, Laboratoire de Physiologie Cellulaire, Équipe Labellisée par la Ligue Contre le Cancer, Villeneuve d'Ascq, F-59655 France; Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, F-59655 France
| | - Christian Slomianny
- *Inserm, U800, Laboratoire de Physiologie Cellulaire, Équipe Labellisée par la Ligue Contre le Cancer, Villeneuve d'Ascq, F-59655 France; Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, F-59655 France
- To whom correspondence should be addressed (email )
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Yoshida J, Ishibashi T, Nishio M. G1 cell cycle arrest by amlodipine, a dihydropyridine Ca2+ channel blocker, in human epidermoid carcinoma A431 cells. Biochem Pharmacol 2006; 73:943-53. [PMID: 17217918 DOI: 10.1016/j.bcp.2006.12.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2006] [Revised: 11/20/2006] [Accepted: 12/11/2006] [Indexed: 01/27/2023]
Abstract
We demonstrated previously that amlodipine, a dihydropyridine Ca(2+) channel blocker, exhibits antitumor effects on human epidermoid carcinoma A431 cells both in vitro and in vivo, in part through inhibition of capacitative Ca(2+) entry. In this study, we examined the effects of amlodipine on cell cycle distribution and cell cycle regulatory molecules in A431 cells, since a rise in intracellular Ca(2+) is required at several points during cell cycle progression. Flow cytometric analysis revealed that treatment with amlodipine (20-30muM, for 24h) induced G1 phase cell accumulation. The amlodipine-induced G1 arrest was associated with a decrease in phosphorylation of retinoblastoma protein (pRB), a regulator of G1 to S phase transition, reduction of protein levels of cyclin D1 and cyclin dependent kinase 4 (CDK4), G1 specific cell cycle proteins, and increased expression of p21(Waf1/Cip1), an inhibitory protein of CDK/cyclin complexes. In vitro kinase assay revealed that amlodipine significantly decreased CDK2-, CDK4-, and their partners cyclin E- and cyclin D1-associated kinase activities. The amlodipine-induced reductions in cyclin D1 protein expression and in CDK2 kinase activity were reproduced by a dihydropyridine derivative, nicardipine, having an inhibitory effect on A431 cell growth, but not by nifedipine, lacking the antiproliferative activity. Our results demonstrate that amlodipine caused G1 cell cycle arrest and growth inhibition in A431 cells through induction of p21(Waf1/Cip1) expression, inhibition of CDK/cyclin-associated kinase activities, and reduced phosphorylation of pRB.
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Affiliation(s)
- Junko Yoshida
- Department of Pharmacology, Kanazawa Medical University, Daigaku 1-1, Uchinada, Ishikawa 920-0293, Japan.
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Nishikawa M, Kira Y, Yabunaka Y, Inoue M. Identification and characterization of endoplasmic reticulum-associated protein, ERp43. Gene 2006; 386:42-51. [PMID: 17020792 DOI: 10.1016/j.gene.2006.06.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2005] [Revised: 06/07/2006] [Accepted: 06/30/2006] [Indexed: 11/28/2022]
Abstract
Disposal of misfolded proteins from the lumen of the endoplasmic reticulum (ER) is one of the quality control mechanisms present in the protein secretory pathway. Through ER-associated degradation, misfolded substrates are targeted to the cytosol where they are degraded by proteasomes. Here we describe the identification of a human ER-associated 43-kD protein (ERp43) by sequencing of the subtraction suppression hybridization cDNA library from ER stress-treated cells. The ERp43 gene encodes a protein of 383 amino acid residues that contains a potential transmembrane domain. Analysis revealed that ERp43 is primarily located in the ER. Quantitative reverse transcriptase-polymerase chain reaction demonstrated that gene expression was relatively high in the neuronal tissues and in the kidney, with ERp43 protein highly expressed in the spinal cord and in the kidney. In cultured cells, overexpression of ERp43 accelerated cell growth and inhibited ER stress-induced cell death, while down-regulation of ERp43 expression decreased proliferation rate and enhanced this type of cell death. These findings indicate that ERp43 plays important roles in cell growth and ER stress-induced cell death.
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Affiliation(s)
- Manabu Nishikawa
- Department of Biochemistry and Molecular Pathology, Osaka City University Medical School, Osaka 545-8585, Japan.
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47
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Chung FY, Lin SR, Lu CY, Yeh CS, Chen FM, Hsieh JS, Huang TJ, Wang JY. Sarco/Endoplasmic Reticulum Calcium-ATPase 2 Expression as a Tumor Marker in Colorectal Cancer. Am J Surg Pathol 2006; 30:969-74. [PMID: 16861967 DOI: 10.1097/00000478-200608000-00006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Maintaining a high calcium concentration in the endoplasmic reticulum through the action of sarco/endoplasmic reticulum calcium-ATPases (SERCAs) is crucial in many cell functions involved in intracellular signal transduction, control of proliferation, programmed cell death, or the synthesis of mature proteins. Recent studies have found that many SERCAs have altered expression patterns in various malignancies. The purpose of the current study was to quantify the expression of SERCA2 in colorectal cancer (CRC) tissues and the corresponding noncancerous tissues, and to statistically analyze whether the SERCA2 expression levels correlate with the clinico-pathologic features and prognosis of CRC patients. Paired colorectal tissue samples from cancerous and the corresponding noncancerous tissues were obtained from 50 patients who underwent surgical resection. Semiquantitative measurements of SERCA2 messenger RNA (mRNA) expression were done using the multiplex reverse transcriptase-polymerase chain reaction. CRC tissues were analyzed through immunohistochemistry for the SERCA2 protein. SERCA2 mRNA overexpression in cancerous tissues compared with normal counterparts was observed in 45 of 50 (90%) patients. The mean expression level of SERCA2 mRNA in cancerous tissues was significantly higher than that in noncancerous tissues (P = 0.01). Increased SERCA2 protein expression was significantly correlated with serosal invasion (P = 0.012), lymph node metastasis (P = 0.009), and advanced tumor stage (P = 0.004). Furthermore, patients with high SERCA2 expression had a significantly poorer overall survival rate than patients with low SERCA2 (P = 0.032). Multivariate analyses indicated that tumor stage (P = 0.015) and SERCA2 expression were independently correlated with overall survival (P = 0.018). The result of this study indicated that SERCA2 may be a molecular determinant in the development and progression of CRC. The molecular mechanisms underlying the SERCA-dependent calcium accumulation and CRC tumorigenesis are worthy of further investigations.
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Affiliation(s)
- Fu-Yen Chung
- Medico Genomic Research Center, Faculty of Medicine, College of Medicine, Kaohsiung Medical University and Chung-Ho Memorial Hospital, Kaohsiung 807, Taiwan
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48
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Devipriya S, Vani G, Ramamurthy N, Shyamaladevi CS. Regulation of Intracellular Calcium Levels and Urokinase Activity in MDA MB 231 Cells by Quercetin. Chemotherapy 2006; 52:60-5. [PMID: 16462139 DOI: 10.1159/000091306] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2004] [Accepted: 05/02/2005] [Indexed: 11/19/2022]
Abstract
BACKGROUND The common plant bioflavonoid, quercetin, is cytotoxic to various tumor cell lines, particularly breast cancer, by affecting the protein-kinase-C-dependent signal pathways and by cell cycle regulation. However, its role in breast cancer metastasis has not been studied so far. Increased uPA activity is evident in highly metastatic breast cancer, which is calcium dependent. METHODS MDA MB 231 cells were treated with various concentrations of quercetin (15-45 microg/ml). The cytotoxic effect of quercetin was assessed by MTT assay and DNA fragmentation analysis. Intracellular calcium levels were measured using Fura-2, a specific Ca2+ fluorescence indicator. Calcium uptake and release in cells treated with quercetin were measured using radioactive 45Ca2+. Urokinase enzyme activity was assayed by a casein zymogram. RESULTS Quercetin elicited dose- and time-dependent cytotoxicity as evidenced by the MTT assay. The maximum effect was observed at 48 h with a quercetin concentration of (45 microg/ml). DNA agarose gel electrophoresis showed dose-dependent DNA fragmentation on quercetin treatment. Quercetin caused significant depletion of cytosolic calcium levels and decreased calcium uptake from the intracellular stores. Casein zymogram showed a marked reduction of urokinase activity as evident by clear lysis bands on a dark background on treatment with quercetin. CONCLUSION Quercetin was found to exhibit cytotoxicity in the highly invasive breast cancer cell line MDA MB 231 in a dose- and time-dependent manner. Quercetin inhibited calcium dependent urokinase activity and hence may prove to be an effective antimetastatic agent.
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Affiliation(s)
- S Devipriya
- Department of Biochemistry, University of Madras, Guindy Campus, Chennai, India
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49
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Choi J, Chiang A, Taulier N, Gros R, Pirani A, Husain M. A calmodulin-binding site on cyclin E mediates Ca2+-sensitive G1/s transitions in vascular smooth muscle cells. Circ Res 2006; 98:1273-81. [PMID: 16627785 DOI: 10.1161/01.res.0000223059.19250.91] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Calcium transients are known to control several transition points in the eukaryotic cell cycle. For example, we have previously shown that a coordinate elevation in the intracellular free calcium ion concentration is required for G1- to S-phase cell cycle progression in vascular smooth muscle cells (VSMC). However, the molecular basis for this Ca2+ sensitivity was not known. Using buffers with differing [Ca2+], we found that the kinase activity of mouse and human cyclin E/CDK2, but not other G1/S-associated cell cycle complexes, was responsive to physiological changes in [Ca2+]. We next determined that this Ca2+-responsive kinase activity was dependent on a direct interaction between calmodulin (CaM), one of the major Ca2+-signal transducers of eukaryotic cells, and cyclin E. Pharmacological inhibition of CaM abrogated the Ca2+ sensitivity of cyclin E/CDK2 and retarded mouse VSMC proliferation by causing G1 arrest. We next defined the presence of a highly conserved 22 amino acid N-terminal CaM-binding motif in mammalian cyclin E genes (dissociation constant, 1.5+/-0.1 micromol/L) and showed its essential role in mediating Ca2+-sensitive kinase activity of cyclin E/CDK2. Mutant human cyclin E protein, lacking this CaM-binding motif, was incapable of binding CaM or responding to [Ca2+]. Taken together, these findings reveal CaM-dependent cyclin E/CDK2 activity as a mediator of the known Ca2+ sensitivity of the G1/S transition of VSMC.
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Affiliation(s)
- Jaehyun Choi
- Heart & Stroke Richard Lewar Centre of Excellence in Cardiovascular Research, Faculty of Medicine, Department of Medicine, University of Toronto, Ontario, Canada
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50
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Kim DH, Hee SQ, Norris AJ, Faull KF, Eckhert CD. Boric acid inhibits adenosine diphosphate-ribosyl cyclase non-competitively. J Chromatogr A 2006; 1115:246-52. [PMID: 16545389 DOI: 10.1016/j.chroma.2006.02.066] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2006] [Revised: 02/15/2006] [Accepted: 02/21/2006] [Indexed: 11/20/2022]
Abstract
Adenosine diphosphate-ribosyl cyclase (ADP-ribosyl cyclase) is a ubiquitous enzyme in eukaryotes that converts NAD+ to cyclic-ADP-ribose (cADPR) and nicotinamide. A quantitative assay for cADPR was developed using capillary electrophoresis to separate NAD+, cADPR, ADP-ribose, and ADP with UV detection (254 nm). Using this assay, the apparent Km and Vmax for Aplysia ADP-ribosyl cyclase were determined to be 1.24+/-0.05 mM and 131.8+/-2.0 microM/min, respectively. Boric acid inhibited ADP-ribosyl cyclase non-competitively with a Ki of 40.5+/-0.5 mM. Boric acid binding to cADPR, determined by electrospray ionization mass spectrometry, was characterized by an apparent binding constant, KA, of 655+/-99 L/mol at pH 10.3.
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Affiliation(s)
- Danny H Kim
- Department of Environmental Health Sciences, Box 951772, University of California, 650 Charles E Young Dr South, Los Angeles, CA 90095-1772, USA
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