151
|
Thomas S, Sharma N, Gonzalez R, Pao PW, Hofman FM, Chen TC, Louie SG, Pirrung MC, Schönthal AH. Repositioning of Verrucosidin, a purported inhibitor of chaperone protein GRP78, as an inhibitor of mitochondrial electron transport chain complex I. PLoS One 2013; 8:e65695. [PMID: 23755268 PMCID: PMC3675020 DOI: 10.1371/journal.pone.0065695] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 05/03/2013] [Indexed: 01/10/2023] Open
Abstract
Verrucosidin (VCD) belongs to a group of fungal metabolites that were identified in screening programs to detect molecules that preferentially kill cancer cells under glucose-deprived conditions. Its mode of action was proposed to involve inhibition of increased GRP78 (glucose regulated protein 78) expression during hypoglycemia. Because GRP78 plays an important role in tumorigenesis, inhibitors such as VCD might harbor cancer therapeutic potential. We therefore sought to characterize VCD's anticancer activity in vitro. Triple-negative breast cancer cell lines MDA-MB-231 and MDA-MB-468 were treated with VCD under different conditions known to trigger increased expression of GRP78, and a variety of cellular processes were analyzed. We show that VCD was highly cytotoxic only under hypoglycemic conditions, but not in the presence of normal glucose levels, and VCD blocked GRP78 expression only when glycolysis was impaired (due to hypoglycemia or the presence of the glycolysis inhibitor 2-deoxyglucose), but not when GRP78 was induced by other means (hypoxia, thapsigargin, tunicamycin). However, VCD's strictly hypoglycemia-specific toxicity was not due to the inhibition of GRP78. Rather, VCD blocked mitochondrial energy production via inhibition of complex I of the electron transport chain. As a result, cellular ATP levels were quickly depleted under hypoglycemic conditions, and common cellular functions, including general protein synthesis, deteriorated and resulted in cell death. Altogether, our study identifies mitochondria as the primary target of VCD. The possibility that other purported GRP78 inhibitors (arctigenin, biguanides, deoxyverrucosidin, efrapeptin, JBIR, piericidin, prunustatin, pyrvinium, rottlerin, valinomycin, versipelostatin) might act in a similar GRP78-independent fashion will be discussed.
Collapse
Affiliation(s)
- Simmy Thomas
- Department of Molecular Microbiology and Immunology, University of Southern California, Los Angeles, California, United States of America
| | - Natasha Sharma
- Department of Pharmaceutical Sciences, University of Southern California, Los Angeles, California, United States of America
| | - Reyna Gonzalez
- Department of Molecular Microbiology and Immunology, University of Southern California, Los Angeles, California, United States of America
| | - Peng-Wen Pao
- Department of Molecular Microbiology and Immunology, University of Southern California, Los Angeles, California, United States of America
| | - Florence M. Hofman
- Department of Pathology, University of Southern California, Los Angeles, California, United States of America
| | - Thomas C. Chen
- Department of Neurosurgery, University of Southern California, Los Angeles, California, United States of America
| | - Stan G. Louie
- Department of Clinical Pharmacy and Pharmaceutical Economics and Policy, University of Southern California, Los Angeles, California, United States of America
| | - Michael C. Pirrung
- Department of Chemistry, University of California Riverside, Riverside, California, United States of America
| | - Axel H. Schönthal
- Department of Molecular Microbiology and Immunology, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
| |
Collapse
|
152
|
Harmatha J, Buděšínský M, Vokáč K, Kostecká P, Kmoníčková E, Zídek Z. Trilobolide and related sesquiterpene lactones from Laser trilobum possessing immunobiological properties. Fitoterapia 2013; 89:157-66. [PMID: 23747321 DOI: 10.1016/j.fitote.2013.05.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 05/23/2013] [Accepted: 05/27/2013] [Indexed: 11/18/2022]
Abstract
Three new and five known sesquiterpene lactones were isolated from the roots of Laser trilobum (L.) Borkh. Chemical identity of the known compounds and structural analysis of the new ones were determined by HR MS and NMR spectroscopy. The two new sesquiterpene lactones: 2-acetoxytrilobolide and 2-hydroxy-10-deacetyltrilobolide belong to the guaianolide type, and the third one, eudeslaserolide, to the biogenetically related eudesmanolide type. Both types, together with their biogenetic precursor of germacranolide type (laserolide) are present in L. trilobum, as well as in the related Laserpitium species. Purposefully selected set of these native sesquiterpene lactones was tested for specific immunobiological properties. The obtained results demonstrate that trilobolide and its acetoxy analog are strong activators of cytokine secretion. On the contrary, the other L. trilobum and Laserpitium siler constituents are only very mild activators, or even inhibitors of the cytokine and nitric oxide production.
Collapse
Affiliation(s)
- Juraj Harmatha
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences, vvi, Prague, Czech Republic.
| | | | | | | | | | | |
Collapse
|
153
|
Xestospongin C induces monocytic differentiation of HL60 cells through activation of the ERK pathway. Food Chem Toxicol 2013; 55:505-12. [DOI: 10.1016/j.fct.2013.01.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 01/14/2013] [Accepted: 01/19/2013] [Indexed: 11/20/2022]
|
154
|
Wang Y, Ma K, Wang P, Baba O, Zhang H, Parent JM, Zheng P, Liu Y, Minassian BA, Liu Y. Laforin prevents stress-induced polyglucosan body formation and Lafora disease progression in neurons. Mol Neurobiol 2013; 48:49-61. [PMID: 23546741 DOI: 10.1007/s12035-013-8438-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 03/04/2013] [Indexed: 11/29/2022]
Abstract
Glycogen, the largest cytosolic macromolecule, is soluble because of intricate construction generating perfect hydrophilic-surfaced spheres. Little is known about neuronal glycogen function and metabolism, though progress is accruing through the neurodegenerative epilepsy Lafora disease (LD) proteins laforin and malin. Neurons in LD exhibit Lafora bodies (LBs), large accumulations of malconstructed insoluble glycogen (polyglucosans). We demonstrated that the laforin-malin complex reduces LBs and protects neuronal cells against endoplasmic reticulum stress-induced apoptosis. We now show that stress induces polyglucosan formation in normal neurons in culture and in the brain. This is mediated by increased glucose-6-phosphate allosterically hyperactivating muscle glycogen synthase (GS1) and is followed by activation of the glycogen digesting enzyme glycogen phosphorylase. In the absence of laforin, stress-induced polyglucosans are undigested and accumulate into massive LBs, and in laforin-deficient mice, stress drastically accelerates LB accumulation and LD. The mechanism through which laforin-malin mediates polyglucosan degradation remains unclear but involves GS1 dephosphorylation by laforin. Our work uncovers the presence of rapid polyglucosan metabolism as part of the normal physiology of neuroprotection. We propose that deficiency in the degradative phase of this metabolism, leading to LB accumulation and resultant seizure predisposition and neurodegeneration, underlies LD.
Collapse
Affiliation(s)
- Yin Wang
- Section of General Surgery, Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI 48109, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
155
|
Schönthal AH. Pharmacological targeting of endoplasmic reticulum stress signaling in cancer. Biochem Pharmacol 2013; 85:653-666. [DOI: 10.1016/j.bcp.2012.09.012] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 09/13/2012] [Accepted: 09/14/2012] [Indexed: 02/08/2023]
|
156
|
Varadarajan S, Tanaka K, Smalley JL, Bampton ETW, Pellecchia M, Dinsdale D, Willars GB, Cohen GM. Endoplasmic reticulum membrane reorganization is regulated by ionic homeostasis. PLoS One 2013; 8:e56603. [PMID: 23457590 PMCID: PMC3574070 DOI: 10.1371/journal.pone.0056603] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 01/14/2013] [Indexed: 01/01/2023] Open
Abstract
Recently we described a new, evolutionarily conserved cellular stress response characterized by a reversible reorganization of endoplasmic reticulum (ER) membranes that is distinct from canonical ER stress and the unfolded protein response (UPR). Apogossypol, a putative broad spectrum BCL-2 family antagonist, was the prototype compound used to induce this ER membrane reorganization. Following microarray analysis of cells treated with apogossypol, we used connectivity mapping to identify a wide range of structurally diverse chemicals from different pharmacological classes and established their ability to induce ER membrane reorganization. Such structural diversity suggests that the mechanisms initiating ER membrane reorganization are also diverse and a major objective of the present study was to identify potentially common features of these mechanisms. In order to explore this, we used hierarchical clustering of transcription profiles for a number of chemicals that induce membrane reorganization and discovered two distinct clusters. One cluster contained chemicals with known effects on Ca2+ homeostasis. Support for this was provided by the findings that ER membrane reorganization was induced by agents that either deplete ER Ca2+ (thapsigargin) or cause an alteration in cellular Ca2+ handling (calmodulin antagonists). Furthermore, overexpression of the ER luminal Ca2+ sensor, STIM1, also evoked ER membrane reorganization. Although perturbation of Ca2+ homeostasis was clearly one mechanism by which some agents induced ER membrane reorganization, influx of extracellular Na+ but not Ca2+ was required for ER membrane reorganization induced by apogossypol and the related BCL-2 family antagonist, TW37, in both human and yeast cells. Not only is this novel, non-canonical ER stress response evolutionary conserved but so also are aspects of the mechanism of formation of ER membrane aggregates. Thus perturbation of ionic homeostasis is important in the regulation of ER membrane reorganization.
Collapse
Affiliation(s)
| | - Kayoko Tanaka
- Department of Biochemistry, University of Leicester, Leicester, United Kingdom
| | - Joshua L. Smalley
- MRC Toxicology Unit, University of Leicester, Leicester, United Kingdom
| | | | | | - David Dinsdale
- MRC Toxicology Unit, University of Leicester, Leicester, United Kingdom
| | - Gary B. Willars
- Department of Cell Physiology and Pharmacology, University of Leicester, Leicester, United Kingdom
| | - Gerald M. Cohen
- MRC Toxicology Unit, University of Leicester, Leicester, United Kingdom
- Department of Biochemistry, University of Leicester, Leicester, United Kingdom
- * E-mail:
| |
Collapse
|
157
|
Grape seed extract enhances eNOS expression and NO production through regulating calcium-mediated AKT phosphorylation in H2O2-treated endothelium. Cell Biol Int 2013; 34:1055-61. [DOI: 10.1042/cbi20100054] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
158
|
4-Phenylbutyric acid reduces endoplasmic reticulum stress, trypsin activation, and acinar cell apoptosis while increasing secretion in rat pancreatic acini. Pancreas 2013; 42:92-101. [PMID: 22889983 DOI: 10.1097/mpa.0b013e318259f6ca] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVES Endoplasmic reticulum (ER) stress leads to misfolded proteins inside the ER and initiates unfolded protein response (UPR). Unfolded protein response components are involved in pancreatic function and activated during pancreatitis. However, the exact role of ER stress in the exocrine pancreas is unclear. The present study examined the effects of 4-phenylbutyric acid (4-PBA), an ER chaperone, on acini and UPR components. METHODS Rat acini were stimulated with cholecystokinin (10 pmol/L to 10 nmol/L) with or without preincubation of 4-PBA. The UPR components were analyzed, including chaperone-binding protein, protein kinaselike ER kinase, X-box-binding protein 1, c-Jun NH(2)-terminal kinase, CCAAT/enhancer-binding protein homologous protein, caspase 3, and apoptosis. Effects of 4-PBA were measured on secretion, calcium, and trypsin activation. RESULTS 4-Phenylbutyric acid led to an increase of secretion, whereas trypsin activation with supraphysiological cholecystokinin was significantly reduced. 4-Phenylbutyric acid prevented chaperone-binding protein up-regulation, diminished protein kinaselike ER kinase, and c-Jun NH2-terminal kinase phosphorylation, prohibited X-box-binding protein 1 splicing and CCAAT/enhancer-binding protein homologous protein expression, caspase 3 activation, and apoptosis caused by supraphysiological cholecystokinin. CONCLUSION By incubation with 4-PBA, beneficial in urea cycle deficiency, it was possible to enhance enzyme secretion to suppress trypsin activation, UPR activation, and proapoptotic pathways. The data hint new perspectives for the use of chemical chaperones in pancreatic diseases.
Collapse
|
159
|
Schönthal AH. Endoplasmic reticulum stress: its role in disease and novel prospects for therapy. SCIENTIFICA 2012; 2012:857516. [PMID: 24278747 PMCID: PMC3820435 DOI: 10.6064/2012/857516] [Citation(s) in RCA: 213] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 11/12/2012] [Indexed: 05/19/2023]
Abstract
The endoplasmic reticulum (ER) is a multifunctional organelle required for lipid biosynthesis, calcium storage, and protein folding and processing. A number of physiological and pathological conditions, as well as a variety of pharmacological agents, are able to disturb proper ER function and thereby cause ER stress, which severely impairs protein folding and therefore poses the risk of proteotoxicity. Specific triggers for ER stress include, for example, particular intracellular alterations (e.g., calcium or redox imbalances), certain microenvironmental conditions (e.g., hypoglycemia, hypoxia, and acidosis), high-fat and high-sugar diet, a variety of natural compounds (e.g., thapsigargin, tunicamycin, and geldanamycin), and several prescription drugs (e.g., bortezomib/Velcade, celecoxib/Celebrex, and nelfinavir/Viracept). The cell reacts to ER stress by initiating a defensive process, called the unfolded protein response (UPR), which is comprised of cellular mechanisms aimed at adaptation and safeguarding cellular survival or, in cases of excessively severe stress, at initiation of apoptosis and elimination of the faulty cell. In recent years, this dichotomic stress response system has been linked to several human diseases, and efforts are underway to develop approaches to exploit ER stress mechanisms for therapy. For example, obesity and type 2 diabetes have been linked to ER stress-induced failure of insulin-producing pancreatic beta cells, and current research efforts are aimed at developing drugs that ameliorate cellular stress and thereby protect beta cell function. Other studies seek to pharmacologically aggravate chronic ER stress in cancer cells in order to enhance apoptosis and achieve tumor cell death. In the following, these principles will be presented and discussed.
Collapse
Affiliation(s)
- Axel H. Schönthal
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, 2011 Zonal Avenue, HMR-405, Los Angeles, CA 90033, USA
| |
Collapse
|
160
|
Mikkelsen MD, Pedas P, Schiller M, Vincze E, Mills RF, Borg S, Møller A, Schjoerring JK, Williams LE, Baekgaard L, Holm PB, Palmgren MG. Barley HvHMA1 is a heavy metal pump involved in mobilizing organellar Zn and Cu and plays a role in metal loading into grains. PLoS One 2012; 7:e49027. [PMID: 23155447 PMCID: PMC3498361 DOI: 10.1371/journal.pone.0049027] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 10/03/2012] [Indexed: 12/11/2022] Open
Abstract
Heavy metal transporters belonging to the P(1B)-ATPase subfamily of P-type ATPases are key players in cellular heavy metal homeostasis. Heavy metal transporters belonging to the P(1B)-ATPase subfamily of P-type ATPases are key players in cellular heavy metal homeostasis. In this study we investigated the properties of HvHMA1, which is a barley orthologue of Arabidopsis thaliana AtHMA1 localized to the chloroplast envelope. HvHMA1 was localized to the periphery of chloroplast of leaves and in intracellular compartments of grain aleurone cells. HvHMA1 expression was significantly higher in grains compared to leaves. In leaves, HvHMA1 expression was moderately induced by Zn deficiency, but reduced by toxic levels of Zn, Cu and Cd. Isolated barley chloroplasts exported Zn and Cu when supplied with Mg-ATP and this transport was inhibited by the AtHMA1 inhibitor thapsigargin. Down-regulation of HvHMA1 by RNA interference did not have an effect on foliar Zn and Cu contents but resulted in a significant increase in grain Zn and Cu content. Heterologous expression of HvHMA1 in heavy metal-sensitive yeast strains increased their sensitivity to Zn, but also to Cu, Co, Cd, Ca, Mn, and Fe. Based on these results, we suggest that HvHMA1 is a broad-specificity exporter of metals from chloroplasts and serve as a scavenging mechanism for mobilizing plastid Zn and Cu when cells become deficient in these elements. In grains, HvHMA1 might be involved in mobilizing Zn and Cu from the aleurone cells during grain filling and germination.
Collapse
Affiliation(s)
- Maria Dalgaard Mikkelsen
- Centre for Membrane Pumps in Cells and Disease (PUMPKIN), Danish National Research Foundation, Frederiksberg, Denmark
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Pai Pedas
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Michaela Schiller
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Eva Vincze
- Department of Molecular Biology and Genetics, Research Centre Flakkebjerg, Aarhus University, Slagelse, Denmark
| | - Rebecca F. Mills
- Centre for Biological Sciences, University of Southampton, Southampton, Hampshire, United Kingdom
| | - Søren Borg
- Department of Molecular Biology and Genetics, Research Centre Flakkebjerg, Aarhus University, Slagelse, Denmark
| | - Annette Møller
- Centre for Membrane Pumps in Cells and Disease (PUMPKIN), Danish National Research Foundation, Frederiksberg, Denmark
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Jan K. Schjoerring
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Lorraine E. Williams
- Centre for Biological Sciences, University of Southampton, Southampton, Hampshire, United Kingdom
| | - Lone Baekgaard
- Centre for Membrane Pumps in Cells and Disease (PUMPKIN), Danish National Research Foundation, Frederiksberg, Denmark
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Preben Bach Holm
- Department of Molecular Biology and Genetics, Research Centre Flakkebjerg, Aarhus University, Slagelse, Denmark
| | - Michael G. Palmgren
- Centre for Membrane Pumps in Cells and Disease (PUMPKIN), Danish National Research Foundation, Frederiksberg, Denmark
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| |
Collapse
|
161
|
Naem E, Haas MJ, Wong NCW, Mooradian AD. Endoplasmic reticulum stress in HepG2 cells inhibits apolipoprotein A-I secretion. Life Sci 2012; 92:72-80. [PMID: 23154241 DOI: 10.1016/j.lfs.2012.11.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 10/03/2012] [Accepted: 10/30/2012] [Indexed: 10/27/2022]
Abstract
AIMS Endoplasmic reticulum (ER) stress modulates gene expression and has been implicated in causing dyslipidemias. To determine if ER stress may contribute to hypoalphalipoproteinemia through suppression of apo A-I gene expression, human hepatoma cell line Hep G2 was treated with ER stress inducers and the changes in apo A-I gene expression were compared to albumin gene expression. MAIN METHODS HepG2 cells were treated with tunicamycin (TM) and thapsigargin (TG), two potent inducers of ER stress, and apo A-I and albumin protein levels, mRNA levels, and promoter activity were measured. ER stress was measured using the ER stress-responsive alkaline phosphatase assay and by Western blot quantitation of ER stress markers such as glucose-regulated protein-78 (GRP-78), phosphorylated Jun N-terminal kinase (phospho-JNK), total JNK, phosphorylated eukaryotic initiation factor 2 alpha (phospho eIF2α), and total eIF2α. KEY FINDINGS TM and TG induced ER stress in HepG2 cells and reduced apo A-I and albumin secretion in a dose-dependent manner. Intracellular albumin levels increased in cells treated with TM and TG while intracellular apo A-I levels decreased. Albumin mRNA and albumin gene promoter activity were reduced in proportion to the decrease in albumin secreted while changes in the apo A-I mRNA levels and promoter activity were modest and did not account for the reduction in apo A-I secretion. SIGNIFICANCE These results indicate that apo A-I secretion is inhibited by ER stress possibly by affecting cellular degradation pathways. However, ER stress does not affect apo A-I secretion by regulating gene expression.
Collapse
Affiliation(s)
- Emad Naem
- The Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Florida, Jacksonville College of Medicine, Jacksonville, FL 32209, USA
| | | | | | | |
Collapse
|
162
|
Novel role for SHP-2 in nutrient-responsive control of S6 kinase 1 signaling. Mol Cell Biol 2012; 33:293-306. [PMID: 23129808 DOI: 10.1128/mcb.01285-12] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Amino acids are required for the activation of the mammalian target of rapamycin complex 1 (mTORC1), which plays a critical role in cell growth, proliferation, and metabolism. The branched-chain amino acid leucine is an essential nutrient that stimulates mTORC1 to promote protein synthesis by activating p70 S6 kinase 1 (S6K1). Here we show that the protein tyrosine phosphatase SHP-2 is required for leucine-induced activation of S6K1 in skeletal myoblasts. In response to leucine, S6K1 activation is inhibited in myoblasts either lacking SHP-2 expression or overexpressing a catalytically inactive mutant of SHP-2. Activation of S6K1 by leucine requires the mobilization of intracellular calcium (Ca(2+)), which we show is mediated by SHP-2 in an inositol-1,4,5-trisphosphate-dependent manner. Ectopic Ca(2+) mobilization rescued the S6K1 activation defect in SHP-2-deficient myoblasts. SHP-2 was identified to act upstream of phospholipase C β4, linking it to the generation of nutrient-induced Ca(2+) release and S6K1 phosphorylation. Consistent with these results, SHP-2-deficient myoblasts exhibited impaired leucine sensing, leading to defective autophagy and reduced myoblast size. These data define a new role for SHP-2 as a nutrient-sensing regulator in skeletal myoblasts that is required for the activation of S6K1.
Collapse
|
163
|
Ordenes VR, Moreno I, Maturana D, Norambuena L, Trewavas AJ, Orellana A. In vivo analysis of the calcium signature in the plant Golgi apparatus reveals unique dynamics. Cell Calcium 2012; 52:397-404. [DOI: 10.1016/j.ceca.2012.06.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Revised: 06/12/2012] [Accepted: 06/23/2012] [Indexed: 12/01/2022]
|
164
|
Li Y, Zhu W, Tao J, Xin P, Liu M, Li J, Wei M. Fasudil protects the heart against ischemia-reperfusion injury by attenuating endoplasmic reticulum stress and modulating SERCA activity: the differential role for PI3K/Akt and JAK2/STAT3 signaling pathways. PLoS One 2012; 7:e48115. [PMID: 23118936 PMCID: PMC3485283 DOI: 10.1371/journal.pone.0048115] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 09/20/2012] [Indexed: 11/22/2022] Open
Abstract
Disordered calcium homeostasis can lead to endoplasmic reticulum (ER) stress. Our previous data showed that time course activation of ER stress contributes to time-related increase in ischemia-reperfusion (I/R) injury. However, it has not been tested whether PI3K/Akt and JAK2/STAT3 pathways play differential roles in reducing ER stress to protect the heart. In the present study, using fasudil which is a specific inhibitor of ROCK, we aimed to investigate whether improved SERCA expression and activity accounts for reduced ER stress by ROCK inhibition, specifically whether PI3K/Akt and JAK2/STAT3 pathways are differentially involved in modulating SERCA activity to reduce ER stress and hence I/R injury. The results showed that during the reperfusion period following 45 min of coronary ligation the infarct size (IS) increased from 3 h of reperfusion (45.4±5.57%) to 24 h reperfusion (64.21±5.43, P<0.05), which was associated with ER stress dependent apoptosis signaling activation including CHOP, Caspase-12 and JNK (P<0.05, respectively).The dynamic ER stress activation was also related to impaired SERCA activity at 24 h of reperfusion. Administration of fasudil at 10 mg/Kg significantly attenuated ROCK activation during reperfusion and resulted in an improved SERCA activity which was closely associated with decreases in temporal activation of ER stress and IS changes. Interestingly, while both PI3K/Akt and JAK2/STAT3 signaling pathways played equal role in the protection offered by ROCK inhibition at 3 h of reperfusion, the rescued SERCA expression and activity at 24 h of reperfusion by fasudil was mainly due to JAK2/STAT3 activation, in which PI3K/Akt signaling shared much less roles.
Collapse
Affiliation(s)
- Yapeng Li
- Division of Cardiology, Shanghai Sixth Hospital, Shanghai Jiao Tong University School of Medicine, State Key Discipline Division, Shanghai, People's of Republic of China
| | - Wei Zhu
- Division of Cardiology, Shanghai Sixth Hospital, Shanghai Jiao Tong University School of Medicine, State Key Discipline Division, Shanghai, People's of Republic of China
- * E-mail: (WZ); (MW)
| | - Jianping Tao
- Division of Cardiology, Shanghai Sixth Hospital, Shanghai Jiao Tong University School of Medicine, State Key Discipline Division, Shanghai, People's of Republic of China
| | - Ping Xin
- Division of Cardiology, Shanghai Sixth Hospital, Shanghai Jiao Tong University School of Medicine, State Key Discipline Division, Shanghai, People's of Republic of China
| | - Mingya Liu
- Division of Cardiology, Shanghai Sixth Hospital, Shanghai Jiao Tong University School of Medicine, State Key Discipline Division, Shanghai, People's of Republic of China
| | - Jingbo Li
- Division of Cardiology, Shanghai Sixth Hospital, Shanghai Jiao Tong University School of Medicine, State Key Discipline Division, Shanghai, People's of Republic of China
| | - Meng Wei
- Division of Cardiology, Shanghai Sixth Hospital, Shanghai Jiao Tong University School of Medicine, State Key Discipline Division, Shanghai, People's of Republic of China
- * E-mail: (WZ); (MW)
| |
Collapse
|
165
|
Andosch A, Affenzeller MJ, Lütz C, Lütz-Meindl U. A freshwater green alga under cadmium stress: ameliorating calcium effects on ultrastructure and photosynthesis in the unicellular model Micrasterias. JOURNAL OF PLANT PHYSIOLOGY 2012; 169:1489-500. [PMID: 22762790 DOI: 10.1016/j.jplph.2012.06.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 06/04/2012] [Accepted: 06/05/2012] [Indexed: 05/23/2023]
Abstract
Cadmium is a highly toxic heavy metal pollutant arising mainly from increasing industrial disposal of electronic components. Due to its high solubility it easily enters soil and aquatic environments. Via its similarity to calcium it may interfere with different kinds of Ca dependent metabolic or developmental processes in biological systems. In the present study we investigate primary cell physiological, morphological and ultrastructural responses of Cd on the unicellular freshwater green alga Micrasterias which has served as a cell biological model system since many years and has proved to be highly sensitive to any kind of abiotic stress. Our results provide evidence that the severe Cd effects in Micrasterias such as unidirectional disintegration of dictyosomes, occurrence of autophagy, decline in photosystem II activity and oxygen production as well as marked structural damage of the chloroplast are based on a disturbance of Ca homeostasis probably by displacement of Ca by Cd. This is indicated by the fact that physiological and structural cadmium effects could be prevented in Micrasterias by pre-treatment with Ca. Additionally, thapsigargin an inhibitor of animal and plant Ca(2+)-ATPase mimicked the adverse Cd induced morphological and functional effects on dictyosomes. Recovery experiments indicated rapid repair mechanisms after Cd stress.
Collapse
Affiliation(s)
- Ancuela Andosch
- Plant Physiology Division, Cell Biology Department, University of Salzburg, Hellbrunnerstraße 34, 5020 Salzburg, Austria
| | | | | | | |
Collapse
|
166
|
Brailoiu GC, Deliu E, Tica AA, Chitravanshi VC, Brailoiu E. Urocortin 3 elevates cytosolic calcium in nucleus ambiguus neurons. J Neurochem 2012; 122:1129-36. [PMID: 22774996 PMCID: PMC3433571 DOI: 10.1111/j.1471-4159.2012.07869.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Urocortin 3 (also known as stresscopin) is an endogenous ligand for the corticotropin-releasing factor receptor 2 (CRF(2)). Despite predominant G(s) coupling of CRF(2), promiscuous coupling with other G proteins has been also associated with the activation of this receptor. As urocortin 3 has been involved in central cardiovascular regulation at hypothalamic and medullary sites, we examined its cellular effects on cardiac vagal neurons of nucleus ambiguus, a key area for the autonomic control of heart rate. Urocortin 3 (1 nM-1000 nM) induced a concentration-dependent increase in cytosolic Ca(2+) concentration that was blocked by the CRF(2) antagonist K41498. In the case of two consecutive treatments with urocortin 3, the second urocortin 3-induced Ca(2+) response was reduced, indicating receptor desensitization. The effect of urocortin 3 was abolished by pre-treatment with pertussis toxin and by inhibition of phospolipase C with U-73122. Urocortin 3 activated Ca(2+) influx via voltage-gated P/Q-type channels as well as Ca(2+) release from endoplasmic reticulum. Urocortin 3 promoted Ca(2+) release via inositol 1,4,5 trisphosphate receptors, but not ryanodine receptors. Our results indicate a novel Ca(2+) -mobilizing effect of urocortin 3 in vagal pre-ganglionic neurons of nucleus ambiguus, providing a cellular mechanism for a previously reported role for this peptide in parasympathetic cardiac regulation.
Collapse
Affiliation(s)
- G Cristina Brailoiu
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, USA.
| | | | | | | | | |
Collapse
|
167
|
Beltran-Parrazal L, Fernandez-Ruiz J, Toledo R, Manzo J, Morgado-Valle C. Inhibition of endoplasmic reticulum Ca²⁺ ATPase in preBötzinger complex of neonatal rat does not affect respiratory rhythm generation. Neuroscience 2012; 224:116-24. [PMID: 22906476 DOI: 10.1016/j.neuroscience.2012.08.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 08/03/2012] [Accepted: 08/13/2012] [Indexed: 10/28/2022]
Abstract
PreBötzinger complex (preBötC) neurons in the brainstem underlie respiratory rhythm generation in vitro. As a result of network interactions, preBötC neurons burst synchronously to produce rhythmic premotor inspiratory activity. Each inspiratory neuron has a characteristic 10-20 mV, 0.3-0.8 s synchronous depolarization known as the inspiratory drive potential or inspiratory envelope, topped by action potentials (APs). Mechanisms involving Ca(2+) fluxes have been proposed to underlie the initiation of the inspiratory drive potential. An important source of intracellular Ca(2+) is the endoplasmic reticulum (ER) in which active Ca(2+) sequestration is mediated by a class of transporters termed sarco/endoplasmic reticulum Ca(2+) ATPases (SERCAs). We aim to test the hypothesis that disruption of Ca(2+) sequestration into the ER affects respiratory rhythm generation. We examined the effect of inhibiting SERCA on respiratory rhythm generation in an in vitro slice preparation. Bath application of the potent SERCA inhibitors thapsigargin or cyclopiazonic acid (CPA) for up to 90 min did not significantly affect the period or amplitude of respiratory-related motor output or integral and duration of inspiratory drive in preBötC neurons. We promoted the depletion of intracellular Ca(2+) stores by a transient bath application of 30 mM K(+) (high K(+)) in the continuous presence of thapsigargin or CPA. After washing out the high K(+), respiratory rhythm period and amplitude returned to baseline values. These results show that after inhibition of SERCA and depletion of intracellular Ca(2+) stores, respiratory rhythm remains substantially the same, suggesting that this source of Ca(2+) does not significantly contribute to rhythm generation in the preBötC in vitro.
Collapse
Affiliation(s)
- L Beltran-Parrazal
- Centro de Investigaciones Cerebrales, Direccion General de Investigaciones, Universidad Veracruzana, Mexico
| | | | | | | | | |
Collapse
|
168
|
Rosa AO, Movafagh S, Cleemann L, Morad M. Hypoxic regulation of cardiac Ca2+ channel: possible role of haem oxygenase. J Physiol 2012; 590:4223-37. [PMID: 22753548 DOI: 10.1113/jphysiol.2012.236570] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Acute and chronic hypoxias are common cardiac diseases that lead often to arrhythmia and impaired contractility. At the cellular level it is unclear whether the suppression of cardiac Ca(2+) channels (Ca(V)1.2) results directly from oxygen deprivation on the channel protein or is mediated by intermediary proteins affecting the channel. To address this question we measured the early effects of hypoxia (5-60 s, P(O(2)) < 5 mmHg) on Ca(2+) current (I(Ca)) and tested the involvement of protein kinase A (PKA) phosphorylation, Ca(2+)/calmodulin-mediated signalling and the haem oxygenase (HO) pathway in the hypoxic regulation of Ca(V)1.2 in rat and cat ventricular myocytes and HEK-293 cells. Hypoxic suppression of ICa) and Ca(2+) transients was significant within 5 s and intensified in the following 50 s, and was reversible. Phosphorylation by cAMP or the phosphatase inhibitor okadaic acid desensitized I(Ca) to hypoxia, while PKA inhibition by H-89 restored the sensitivity of I(Ca) to hypoxia. This phosphorylation effect was specific to Ca(2+), but not Ba(2+) or Na(+), permeating through the channel. CaMKII inhibitory peptide and Bay K8644 reversed the phosphorylation-induced desensitization to hypoxia. Mutation of CAM/CaMKII-binding motifs of the α(1c) subunit of Ca(V)1.2 fully desensitized the Ca(2+) channel to hypoxia. Rapid application of HO inhibitors (zinc protoporphyrin (ZnPP) and tin protoporphyrin (SnPP)) suppressed the channel in a manner similar to acute hypoxia such that: (1) I(Ca) and I(Ba) were suppressed within 5 s of ZnPP application; (2) PKA activation and CaMKII inhibitors desensitized I(Ca), but not I(Ba), to ZnPP; and (3) hypoxia failed to further suppress I(Ca) and I(Ba) in ZnPP-treated myocytes. We propose that the binding of HO to the CaM/CaMKII-specific motifs on Ca(2+) channel may mediate the rapid response of the channel to hypoxia.
Collapse
Affiliation(s)
- Angelo O Rosa
- Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina and Clemson University, Charleston, SC 29245, USA
| | | | | | | |
Collapse
|
169
|
Zeng L, Wang Y, Baba O, Zheng P, Liu Y, Liu Y. Laforin is required for the functional activation of malin in endoplasmic reticulum stress resistance in neuronal cells. FEBS J 2012; 279:2467-78. [PMID: 22578008 DOI: 10.1111/j.1742-4658.2012.08627.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Mutations in either EPM2A, the gene encoding a dual-specificity phosphatase named laforin, or NHLRC1, the gene encoding an E3 ubiquitin ligase named malin, cause Lafora disease in humans. Lafora disease is a fatal neurological disorder characterized by progressive myoclonus epilepsy, severe neurological deterioration and accumulation of poorly branched glycogen inclusions, called Lafora bodies or polyglucosan bodies, within the cell cytoplasm. The molecular mechanism underlying the neuropathogenesis of Lafora disease remains unknown. Here, we present data demonstrating that in the cells expressing low levels of laforin protein, overexpressed malin and its Lafora disease-causing missense mutants are stably polyubiquitinated. Malin and malin mutants form ubiquitin-positive aggregates in or around the nuclei of the cells in which they are expressed. Neither wild-type malin nor its mutants elicit endoplasmic reticulum stress, although the mutants exaggerate the response to endoplasmic reticulum stress. Overexpressed laforin impairs the polyubiquitination of malin while it recruits malin to polyglucosan bodies. The recruitment and activities of laforin and malin are both required for the polyglucosan body disruption. Consistently, targeted deletion of laforin in brain cells from Epm2a knockout mice increases polyubiquitinated proteins. Knockdown of Epm2a or Nhlrc1 in neuronal Neuro2a cells shows that they cooperate to allow cells to resist ER stress and apoptosis. These results reveal that a functional laforin-malin complex plays a critical role in disrupting Lafora bodies and relieving ER stress, implying that a causative pathogenic mechanism underlies their deficiency in Lafora disease.
Collapse
Affiliation(s)
- Li Zeng
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI 48109, USA
| | | | | | | | | | | |
Collapse
|
170
|
Glembotski CC, Thuerauf DJ, Huang C, Vekich JA, Gottlieb RA, Doroudgar S. Mesencephalic astrocyte-derived neurotrophic factor protects the heart from ischemic damage and is selectively secreted upon sarco/endoplasmic reticulum calcium depletion. J Biol Chem 2012; 287:25893-904. [PMID: 22637475 DOI: 10.1074/jbc.m112.356345] [Citation(s) in RCA: 152] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The endoplasmic reticulum (ER) stress protein mesencephalic astrocyte-derived neurotrophic factor (MANF) has been reported to protect cells from stress-induced cell death before and after its secretion; however, the conditions under which it is secreted are not known. Accordingly, we examined the mechanism of MANF release from cultured ventricular myocytes and HeLa cells, both of which secrete proteins via the constitutive pathway. Although the secretion of proteins via the constitutive pathway is not known to increase upon changes in intracellular calcium, MANF secretion was increased within 30 min of treating cells with compounds that deplete sarcoplasmic reticulum (SR)/ER calcium. In contrast, secretion of atrial natriuretic factor from ventricular myocytes was not increased by SR/ER calcium depletion, suggesting that not all secreted proteins exhibit the same characteristics as MANF. We postulated that SR/ER calcium depletion triggered MANF secretion by decreasing its retention. Consistent with this were co-immunoprecipitation and live cell, zero distance, photo affinity cross-linking, demonstrating that, in part, MANF was retained in the SR/ER via its calcium-dependent interaction with the SR/ER-resident protein, GRP78 (glucose-regulated protein 78 kDa). This unusual mechanism of regulating secretion from the constitutive secretory pathway provides a potentially missing link in the mechanism by which extracellular MANF protects cells from stresses that deplete SR/ER calcium. Consistent with this was our finding that administration of recombinant MANF to mice decreased tissue damage in an in vivo model of myocardial infarction, a condition during which ER calcium is known to be dysregulated, and MANF expression is induced.
Collapse
Affiliation(s)
- Christopher C Glembotski
- San Diego State University Heart Institute, and Department of Biology, San Diego State University, San Diego, California 92182, USA.
| | | | | | | | | | | |
Collapse
|
171
|
LIM domain only 4 (LMO4) regulates calcium-induced calcium release and synaptic plasticity in the hippocampus. J Neurosci 2012; 32:4271-83. [PMID: 22442089 DOI: 10.1523/jneurosci.6271-11.2012] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The LIM domain only 4 (LMO4) transcription cofactor activates gene expression in neurons and regulates key aspects of network formation, but the mechanisms are poorly understood. Here, we show that LMO4 positively regulates ryanodine receptor type 2 (RyR2) expression, thereby suggesting that LMO4 regulates calcium-induced calcium release (CICR) in central neurons. We found that CICR modulation of the afterhyperpolarization in CA3 neurons from mice carrying a forebrain-specific deletion of LMO4 (LMO4 KO) was severely compromised but could be restored by single-cell overexpression of LMO4. In line with these findings, two-photon calcium imaging experiments showed that the potentiation of RyR-mediated calcium release from internal stores by caffeine was absent in LMO4 KO neurons. The overall facilitatory effect of CICR on glutamate release induced during trains of action potentials was likewise defective in LMO4 KO, confirming that CICR machinery is severely compromised in these neurons. Moreover, the magnitude of CA3-CA1 long-term potentiation was reduced in LMO4 KO mice, a defect that appears to be secondary to an overall reduced glutamate release probability. These cellular phenotypes in LMO4 KO mice were accompanied with deficits in hippocampus-dependent spatial learning as determined by the Morris water maze test. Thus, our results establish LMO4 as a key regulator of CICR in central neurons, providing a mechanism for LMO4 to modulate a wide range of neuronal functions and behavior.
Collapse
|
172
|
Sato Y, Hatta M, Karim MF, Sawa T, Wei FY, Sato S, Magnuson MA, Gonzalez FJ, Tomizawa K, Akaike T, Yoshizawa T, Yamagata K. Anks4b, a novel target of HNF4α protein, interacts with GRP78 protein and regulates endoplasmic reticulum stress-induced apoptosis in pancreatic β-cells. J Biol Chem 2012; 287:23236-45. [PMID: 22589549 DOI: 10.1074/jbc.m112.368779] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations of the HNF4A gene cause a form of maturity-onset diabetes of the young (MODY1) that is characterized by impairment of pancreatic β-cell function. HNF4α is a transcription factor belonging to the nuclear receptor superfamily (NR2A1), but its target genes in pancreatic β-cells are largely unknown. Here, we report that ankyrin repeat and sterile α motif domain containing 4b (Anks4b) is a target of HNF4α in pancreatic β-cells. Expression of Anks4b was decreased in both βHNF4α KO islets and HNF4α knockdown MIN6 β-cells, and HNF4α activated Anks4b promoter activity. Anks4b bound to glucose-regulated protein 78 (GRP78), a major endoplasmic reticulum (ER) chaperone protein, and overexpression of Anks4b enhanced the ER stress response and ER stress-associated apoptosis of MIN6 cells. Conversely, suppression of Anks4b reduced β-cell susceptibility to ER stress-induced apoptosis. These results indicate that Anks4b is a HNF4α target gene that regulates ER stress in β-cells by interacting with GRP78, thus suggesting that HNF4α is involved in maintenance of the ER.
Collapse
Affiliation(s)
- Yoshifumi Sato
- Department of Medical Biochemistry, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
173
|
West DC, Qin Y, Peterson QP, Thomas DL, Palchaudhuri R, Morrison KC, Lucas PW, Palmer AE, Fan TM, Hergenrother PJ. Differential effects of procaspase-3 activating compounds in the induction of cancer cell death. Mol Pharm 2012; 9:1425-34. [PMID: 22486564 DOI: 10.1021/mp200673n] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The evasion of apoptosis is a key characteristic of cancer, and thus strategies to selectively induce apoptosis in cancer cells hold considerable promise in personalized anticancer therapy. Structurally similar procaspase activating compounds PAC-1 and S-PAC-1 restore procaspase-3 activity through the chelation of inhibitory zinc ions in vitro, induce apoptotic death of cancer cells in culture, and reduce tumor burden in vivo. Ip or iv administrations of high doses of PAC-1 are transiently neurotoxic in vivo, while S-PAC-1 is safe even at very high doses and has been evaluated in a phase I clinical trial of pet dogs with spontaneously occurring lymphoma. Here we show that PAC-1 and S-PAC-1 have similar mechanisms of cell death induction at low concentrations (less than 50 μM), but at high concentrations PAC-1 displays unique cell death induction features. Cells treated with a high concentration of PAC-1 have a distinctive gene expression profile, unusual cellular and mitochondrial morphology, and an altered intracellular Ca(2+) concentration, indicative of endoplasmic reticulum (ER) stress-induced apoptosis. These studies suggest strategies for anticancer clinical development, specifically bolus dosing for PAC-1 and continuous rate infusion for S-PAC-1.
Collapse
Affiliation(s)
- Diana C West
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | | | | | | | | | | | | | | | | | | |
Collapse
|
174
|
McMullen DC, Kean WS, Verma A, Cole JT, Watson WD. A microplate technique to simultaneously assay calcium accumulation in endoplasmic reticulum and SERCA release of inorganic phosphate. Biol Proced Online 2012; 14:4. [PMID: 22472432 PMCID: PMC3388579 DOI: 10.1186/1480-9222-14-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 04/02/2012] [Indexed: 01/02/2023] Open
Abstract
Traditional analyses of calcium homeostasis have separately quantified either calcium accumulation or release mechanisms. To define the system as a whole, however, requires multiple experimental techniques to examine both accumulation and release. Here we describe a technique that couples the simultaneous quantification of radio-labeled calcium accumulation in endoplasmic reticulum (ER) microsomes with the release of inorganic phosphate (Pi) by the hydrolytic activity of sarco-endoplasmic reticulum calcium ATPase (SERCA) all in the convenience of a 96-well format.
Collapse
Affiliation(s)
- David C McMullen
- Department of Neurology, Uniformed Services University of the Health Sciences, B-3059, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
| | | | | | | | | |
Collapse
|
175
|
Nimitvilai S, Arora DS, Brodie MS. Reversal of dopamine inhibition of dopaminergic neurons of the ventral tegmental area is mediated by protein kinase C. Neuropsychopharmacology 2012; 37:543-56. [PMID: 21976045 PMCID: PMC3242316 DOI: 10.1038/npp.2011.222] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Adaptation of putative dopaminergic (pDA) neurons in the ventral tegmental area (VTA) to drugs of abuse may alter information processing related to reward and reinforcement and is an important factor in the development of addiction. We have demonstrated that prolonged increases in the concentration of dopamine (DA) result in a time-dependent decrease in sensitivity of pDA neurons to DA, which we termed DA inhibition reversal (DIR). In this study, we used extracellular recordings to examine factors mediating DIR. A 40 min administration of DA (2.5-10 μM), but not the DA D2 receptor agonist quinpirole (50-200 nM), resulted in inhibition of neuronal firing followed by DIR. In the presence of 100 nM cocaine, inhibition followed by DIR was seen with much lower DA concentrations. Reversal of quinpirole inhibition could be induced by an activator of protein kinase C, but not of protein kinase A. Inhibitors of protein kinase C or phospholipase C blocked the development of DIR. Disruption of intracellular calcium release also prevented DIR. Reduction of extracellular calcium or inhibition of store-operated calcium entry blocked DIR, but the L-type calcium channel blocker nifedipine did not. DIR was age-dependent and not seen in pDA VTA neurons from rat pups younger than 15 days postnatally. Our data indicate that DIR is mediated by protein kinase C, and implicate a conventional protein kinase C. This characterization of DIR gives insight into the regulation of autoinhibition of pDA VTA neurons, and the resulting long-term alteration in information processing related to reward and reinforcement.
Collapse
Affiliation(s)
- Sudarat Nimitvilai
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL, USA
| | - Devinder S Arora
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL, USA
| | - Mark S Brodie
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL, USA,Department of Physiology and Biophysics, University of Illinois at Chicago, 835 South Wolcott, Room E-202, M/C 901, Chicago, IL 60612-7342, USA, Tel: +1 312 996 2373, Fax: +1 312 996 1414, E-mail:
| |
Collapse
|
176
|
Abstract
It has been known for more than 60 years, and suspected for over 100, that alveolar hypoxia causes pulmonary vasoconstriction by means of mechanisms local to the lung. For the last 20 years, it has been clear that the essential sensor, transduction, and effector mechanisms responsible for hypoxic pulmonary vasoconstriction (HPV) reside in the pulmonary arterial smooth muscle cell. The main focus of this review is the cellular and molecular work performed to clarify these intrinsic mechanisms and to determine how they are facilitated and inhibited by the extrinsic influences of other cells. Because the interaction of intrinsic and extrinsic mechanisms is likely to shape expression of HPV in vivo, we relate results obtained in cells to HPV in more intact preparations, such as intact and isolated lungs and isolated pulmonary vessels. Finally, we evaluate evidence regarding the contribution of HPV to the physiological and pathophysiological processes involved in the transition from fetal to neonatal life, pulmonary gas exchange, high-altitude pulmonary edema, and pulmonary hypertension. Although understanding of HPV has advanced significantly, major areas of ignorance and uncertainty await resolution.
Collapse
Affiliation(s)
- J. T. Sylvester
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| | - Larissa A. Shimoda
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| | - Philip I. Aaronson
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| | - Jeremy P. T. Ward
- Division of Pulmonary & Critical Care Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland; and Division of Asthma, Allergy and Lung Biology, School of Medicine, King's College, London, United Kingdom
| |
Collapse
|
177
|
Klüver N, Yang L, Busch W, Scheffler K, Renner P, Strähle U, Scholz S. Transcriptional response of zebrafish embryos exposed to neurotoxic compounds reveals a muscle activity dependent hspb11 expression. PLoS One 2011; 6:e29063. [PMID: 22205996 PMCID: PMC3242778 DOI: 10.1371/journal.pone.0029063] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 11/20/2011] [Indexed: 01/13/2023] Open
Abstract
Acetylcholinesterase (AChE) inhibitors are widely used as pesticides and drugs. Their primary effect is the overstimulation of cholinergic receptors which results in an improper muscular function. During vertebrate embryonic development nerve activity and intracellular downstream events are critical for the regulation of muscle fiber formation. Whether AChE inhibitors and related neurotoxic compounds also provoke specific changes in gene transcription patterns during vertebrate development that allow them to establish a mechanistic link useful for identification of developmental toxicity pathways has, however, yet not been investigated. Therefore we examined the transcriptomic response of a known AChE inhibitor, the organophosphate azinphos-methyl (APM), in zebrafish embryos and compared the response with two non-AChE inhibiting unspecific control compounds, 1,4-dimethoxybenzene (DMB) and 2,4-dinitrophenol (DNP). A highly specific cluster of APM induced gene transcripts was identified and a subset of strongly regulated genes was analyzed in more detail. The small heat shock protein hspb11 was found to be the most sensitive induced gene in response to AChE inhibitors. Comparison of expression in wildtype, ache and sop(fixe) mutant embryos revealed that hspb11 expression was dependent on the nicotinic acetylcholine receptor (nAChR) activity. Furthermore, modulators of intracellular calcium levels within the whole embryo led to a transcriptional up-regulation of hspb11 which suggests that elevated intracellular calcium levels may regulate the expression of this gene. During early zebrafish development, hspb11 was specifically expressed in muscle pioneer cells and Hspb11 morpholino-knockdown resulted in effects on slow muscle myosin organization. Our findings imply that a comparative toxicogenomic approach and functional analysis can lead to the identification of molecular mechanisms and specific marker genes for potential neurotoxic compounds.
Collapse
Affiliation(s)
- Nils Klüver
- Department of Bioanalytical Ecotoxicology, UFZ-Helmholtz Centre for Environmental Research, Leipzig, Germany.
| | | | | | | | | | | | | |
Collapse
|
178
|
Wang Y, Bruce AT, Tu C, Ma K, Zeng L, Zheng P, Liu Y, Liu Y. Protein aggregation of SERCA2 mutants associated with Darier disease elicits ER stress and apoptosis in keratinocytes. J Cell Sci 2011; 124:3568-80. [PMID: 22045735 DOI: 10.1242/jcs.084053] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Mutations in sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA2) underlie Darier disease (DD), a dominantly inherited skin disorder characterized by loss of keratinocyte adhesion (acantholysis) and abnormal keratinization (dyskeratosis) resulting in characteristic mucocutaneous abnormalities. However, the molecular pathogenic mechanism by which these changes influence keratinocyte adhesion and viability remains unknown. We show here that SERCA2 protein is extremely sensitive to endoplasmic reticulum (ER) stress, which typically results in aggregation and insolubility of the protein. Depletion of ER calcium stores is not necessary for the aggregation but accelerates the progression. Systematic analysis of diverse mutants identical to those found in DD patients demonstrated that the ER stress initiator is the SERCA2 mutant protein itself. These SERCA2 proteins were found to be less soluble, to aggregate and to be more polyubiquitinylated. After transduction into primary human epidermal keratinocytes, mutant SERCA2 aggregates elicited ER stress, caused increased numbers of cells to round up and detach from the culture plate, and induced apoptosis. These mutant induced events were exaggerated by increased ER stress. Furthermore, knockdown SERCA2 in keratinocytes rendered the cells resistant to apoptosis induction. These features of SERCA2 and its mutants establish a mechanistic base to further elucidate the molecular pathogenesis underlying acantholysis and dyskeratosis in DD.
Collapse
Affiliation(s)
- Yin Wang
- Department of Surgery, Division of Immunotherapy, Section of General Surgery, University of Michigan Medical Center, Ann Arbor, MI 48109, USA.
| | | | | | | | | | | | | | | |
Collapse
|
179
|
Yoshikawa T, Ogata N, Izuta H, Shimazawa M, Hara H, Takahashi K. Increased Expression of Tight Junctions in ARPE-19 Cells Under Endoplasmic Reticulum Stress. Curr Eye Res 2011; 36:1153-63. [DOI: 10.3109/02713683.2011.606592] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Tadanobu Yoshikawa
- Department of Ophthalmology, Kansai Medical University,
Takii Hospital, Osaka, Japan
| | - Nahoko Ogata
- Department of Ophthalmology, Nara Medical University,
Nara, Japan
| | - Hiroshi Izuta
- Department of Biofunctional Evaluation Molecular Pharmacology, Gifu Pharmaceutical University,
Gifu, Japan
| | - Masamitsu Shimazawa
- Department of Biofunctional Evaluation Molecular Pharmacology, Gifu Pharmaceutical University,
Gifu, Japan
| | - Hideaki Hara
- Department of Biofunctional Evaluation Molecular Pharmacology, Gifu Pharmaceutical University,
Gifu, Japan
| | - Kanji Takahashi
- Department of Ophthalmology, Kansai Medical University,
Hirakata Hospital, Osaka, Japan
| |
Collapse
|
180
|
Haraki T, Yasuda T, Mukaida K, Migita T, Hamada H, Kawamoto M. Mutated p.4894 RyR1 function related to malignant hyperthermia and congenital neuromuscular disease with uniform type 1 fiber (CNMDU1). Anesth Analg 2011; 113:1461-7. [PMID: 21926372 DOI: 10.1213/ane.0b013e318232053e] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Ryanodine receptor 1 (RyR1) is a Ca(2+) release channel located in the sarcoplasmic reticulum membrane of skeletal muscle. More than 200 variants in RyR1 have been identified in DNA from patients with malignant hyperthermia (MH) and congenital myopathies; only 30 have been sufficiently studied so as to be identified as MH-causative mutations. The Ala4894Thr RyR1 variant was found in a Japanese patient with susceptibility to MH, and the Ala4894Pro variant in a rare case of myopathy: congenital neuromuscular disease with uniform type 1 fiber (CNMDU1). We hypothesized that different Ala4894 variants of RyR1 cause different pathophysiological changes that are identifiable by having differing pharmacological sensitivities to RYR1 agonists. METHODS Expression vector with a mutation in RYR1 corresponding to the Ala4894Thr, Ala4894Pro, Ala4894Ser, or Ala 4894Gly variant of human RyR1 was transfected into human embryonic kidney 293 cells. At 72 hours after transfection, we determined the intracellular Ca(2+) changes induced by caffeine and 4-chloro-m-cresol (4CmC), in the presence or absence of dantrolene. RESULTS Ala4894Thr-transfected cells and Ala4894Ser-transfected cells were more sensitive to caffeine than the wild type, and Ala4894Thr-transfected cells were also more sensitive to 4CmC than the wild type, whereas Ala4894Pro-transfected cells had no response to caffeine or 4CmC. Ala4894Gly-transfected cells were significantly less sensitive to caffeine than the wild type. In addition, the responses of Ala4894Thr-transfected cells and Ala4894Ser-transfected cells to caffeine were suppressed by dantrolene. CONCLUSION We concluded that different Ala4894 variants of RyR1 lead to different agonist/antagonist sensitivities, which may predict differing RYR1 functionality during excitation-contraction coupling and sensitivity to MH. The hypersensitive Ala4894Thr-RyR1 is associated with MH and the poorly functional Ala4894Pro-RyR1 with CNMDU1.
Collapse
Affiliation(s)
- Toshiaki Haraki
- Department of Anesthesiology and Critical Care, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
| | | | | | | | | | | |
Collapse
|
181
|
Mahdi SH, Yamasaki H, Otaki JM. Heat-shock-induced color-pattern changes of the blue pansy butterfly Junonia orithya: Physiological and evolutionary implications. J Therm Biol 2011. [DOI: 10.1016/j.jtherbio.2011.06.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
182
|
Zimmerman MC, Takapoo M, Jagadeesha DK, Stanic B, Banfi B, Bhalla RC, Miller FJ. Activation of NADPH oxidase 1 increases intracellular calcium and migration of smooth muscle cells. Hypertension 2011; 58:446-53. [PMID: 21810651 DOI: 10.1161/hypertensionaha.111.177006] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Redox-dependent migration and proliferation of vascular smooth muscle cells (SMCs) are central events in the development of vascular proliferative diseases; however, the underlying intracellular signaling mechanisms are not fully understood. We tested the hypothesis that activation of Nox1 NADPH oxidase modulates intracellular calcium ([Ca(2+)](i)) levels. Using cultured SMCs from wild-type and Nox1 null mice, we confirmed that thrombin-dependent generation of reactive oxygen species requires Nox1. Thrombin rapidly increased [Ca(2+)](i), as measured by fura-2 fluorescence ratio imaging, in wild-type but not Nox1 null SMCs. The increase in [Ca(2+)](i) in wild-type SMCs was inhibited by antisense to Nox1 and restored by expression of Nox1 in Nox1 null SMCs. Investigation into potential mechanisms by which Nox1 modulates [Ca(2+)](i) showed that thrombin-induced inositol triphosphate generation and thapsigargin-induced intracellular calcium mobilization were similar in wild-type and Nox1 null SMCs. To examine the effects of Nox1 on Ca(2+) entry, cells were either bathed in Ca(2+)-free medium or exposed to dihydropyridines to block L-type Ca(2+) channel activity. Treatment with nifedipine or removal of extracellular Ca(2+) reduced the thrombin-mediated increase of [Ca(2+)](i) in wild-type SMCs, whereas the response in Nox1 null SMCs was unchanged. Sodium vanadate, an inhibitor of protein tyrosine phosphatases, restored the thrombin-induced increase of [Ca(2+)](i) in Nox1 null SMCs. Migration of SMCs was impaired with deficiency of Nox1 and restored with expression of Nox1 or the addition of sodium vanadate. In summary, we conclude that Nox1 NADPH oxidase modulates Ca(2+) mobilization in SMCs, in part through regulation of Ca(2+) influx, to thereby promote cell migration.
Collapse
Affiliation(s)
- Matthew C Zimmerman
- Jr, University of Iowa, 285 Newton Rd, Room 2269 CBRB, Iowa City, IA 52242, USA
| | | | | | | | | | | | | |
Collapse
|
183
|
Báez-Ruiz A, Díaz-Muñoz M. Chronic inhibition of endoplasmic reticulum calcium-release channels and calcium-ATPase lengthens the period of hepatic clock gene Per1. J Circadian Rhythms 2011; 9:6. [PMID: 21740569 PMCID: PMC3142245 DOI: 10.1186/1740-3391-9-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 07/08/2011] [Indexed: 11/17/2022] Open
Abstract
Background The role played by calcium as a regulator of circadian rhythms is not well understood. The effect of the pharmacological inhibition of the ryanodine receptor (RyR), inositol 1,4,5-trisphosphate receptor (IP3R), and endoplasmic-reticulum Ca2+-ATPase (SERCA), as well as the intracellular Ca2+-chelator BAPTA-AM was explored on the 24-h rhythmicity of the liver-clock protein PER1 in an experimental model of circadian synchronization by light and restricted-feeding schedules. Methods Liver explants from Period1-luciferase (Per1-luc) transgenic rats with either free food access or with a restricted meal schedule were treated for several days with drugs to inhibit the activity of IP3Rs (2-APB), RyRs (ryanodine), or SERCA (thapsigargin) as well as to suppress intracellular calcium fluctuations (BAPTA-AM). The period of Per1-luc expression was measured during and after drug administration. Results Liver explants from rats fed ad libitum showed a lengthened period in response to all the drugs tested. The pharmacological treatments of the explants from meal-entrained rats induced the same pattern, with the exception of the ryanodine treatment which, unexpectedly, did not modify the Per1-luc period. All effects associated with drug application were reversed after washout, indicating that none of the pharmacological treatments was toxic to the liver cultures. Conclusions Our data suggest that Ca2+ mobilized from internal deposits modulates the molecular circadian clock in the liver of rats entrained by light and by restricted meal access.
Collapse
Affiliation(s)
- Adrián Báez-Ruiz
- Departament de Neurobiología Moleculary Celular, Instituto de Neurobiología, UNAM-Juriquilla, Boulevard Juriquilla #3001, Apdo, Postal 1-1141, Querétaro, QRO, 76230, México.
| | | |
Collapse
|
184
|
Anshu A, Thomas S, Agarwal P, Ibarra-Rivera TR, Pirrung MC, Schönthal AH. Novel proteasome-inhibitory syrbactin analogs inducing endoplasmic reticulum stress and apoptosis in hematological tumor cell lines. Biochem Pharmacol 2011; 82:600-9. [PMID: 21736873 DOI: 10.1016/j.bcp.2011.06.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2011] [Revised: 06/17/2011] [Accepted: 06/20/2011] [Indexed: 12/29/2022]
Abstract
The proteasome has been recognized as a druggable target in cancer cells, and this has led to searches for pharmacologic agents that target this cellular organelle for cancer therapeutic purposes. Syrbactins are a group of microbial metabolites consisting of two related families, the glidobactins and the syringolins. Some members of this group have revealed cytotoxic efficacy in tumor cells, and more recently it was discovered that they exert proteasome-inhibitory function. Based on this therapeutic promise and to gain further understanding of their molecular modes of action, we chemically synthesized de-novo three novel syrbactin analogs and characterized their proteasome-inhibitory and in vitro anti-neoplastic activity in human cell lines representing multiple myeloma, Waldenström's macroglobulinemia, and lymphocytic leukemia. Our results show that two of these novel compounds are able to inhibit proteasome activity in the nanomolar range, reduce the expression of anti-apoptotic proteins survivin and Mcl-1, and cause severe endoplasmic reticulum (ER) stress, resulting in pronounced tumor cell death. These anticancer effects can be synergistically enhanced when the agents are combined with thapsigargin, which further aggravates ER stress by a different mechanism. Taken together, our findings support the notion that syrbactin analogs may provide a structural platform for the development of novel cancer therapeutics, and that their efficacy may be further increased when complemented with other agents that trigger ER stress.
Collapse
Affiliation(s)
- Ashish Anshu
- Department of Molecular Microbiology & Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089-9094, USA
| | | | | | | | | | | |
Collapse
|
185
|
Deldicque L, Bertrand L, Patton A, Francaux M, Baar K. ER stress induces anabolic resistance in muscle cells through PKB-induced blockade of mTORC1. PLoS One 2011; 6:e20993. [PMID: 21698202 PMCID: PMC3116857 DOI: 10.1371/journal.pone.0020993] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 05/17/2011] [Indexed: 12/31/2022] Open
Abstract
Background Anabolic resistance is the inability to increase protein synthesis in response to an increase in amino acids following a meal. One potential mediator of anabolic resistance is endoplasmic reticulum (ER) stress. The purpose of the present study was to test whether ER stress impairs the response to growth factors and leucine in muscle cells. Methods Muscle cells were incubated overnight with tunicamycin or thapsigargin to induce ER stress and the activation of the unfolded protein response, mTORC1 activity at baseline and following insulin and amino acids, as well as amino acid transport were determined. Results ER stress decreased basal phosphorylation of PKB and S6K1 in a dose-dependent manner. In spite of the decrease in basal PKB phosphorylation, insulin (10–50 nM) could still activate both PKB and S6K1. The leucine (2.5–5 mM)-induced phosphorylation of S6K1 on the other hand was repressed by low concentrations of both tunicamycin and thapsigargin. To determine the mechanism underlying this anabolic resistance, several inhibitors of mTORC1 activation were measured. Tunicamycin and thapsigargin did not change the phosphorylation or content of either AMPK or JNK, both increased TRB3 mRNA expression and thapsigargin increased REDD1 mRNA. Tunicamycin and thapsigargin both decreased the basal phosphorylation state of PRAS40. Neither tunicamycin nor thapsigargin prevented phosphorylation of PRAS40 by insulin. However, since PKB is not activated by amino acids, PRAS40 phosphorylation remained low following the addition of leucine. Blocking PKB using a specific inhibitor had the same effect on both PRAS40 and leucine-induced phosphorylation of S6K1. Conclusion ER stress induces anabolic resistance in muscle cells through a PKB/PRAS40-induced blockade of mTORC1.
Collapse
Affiliation(s)
- Louise Deldicque
- Université catholique de Louvain, Institute of Neuroscience, Research Group in Muscle and Exercise Physiology, Louvain-la-Neuve, Belgium
- Research Centre for Exercise and Health, Department of Biomedical Kinesiology, K.U. Leuven, Leuven, Belgium
| | - Luc Bertrand
- Université catholique de Louvain, Institut de Recherche Expérimentale et Clinique, Pole of Cardiovascular Research, Woluwe-Saint-Lambert, Belgium
| | - Amy Patton
- Department of Neurobiology, Physiology and Behaviour, University of California Davis, Davis, California, United States of America
| | - Marc Francaux
- Université catholique de Louvain, Institute of Neuroscience, Research Group in Muscle and Exercise Physiology, Louvain-la-Neuve, Belgium
| | - Keith Baar
- Department of Neurobiology, Physiology and Behaviour, University of California Davis, Davis, California, United States of America
- * E-mail:
| |
Collapse
|
186
|
Tvermoes BE, Bird GS, Freedman JH. Cadmium induces transcription independently of intracellular calcium mobilization. PLoS One 2011; 6:e20542. [PMID: 21694771 PMCID: PMC3111418 DOI: 10.1371/journal.pone.0020542] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 05/05/2011] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Exposure to cadmium is associated with human pathologies and altered gene expression. The molecular mechanisms by which cadmium affects transcription remain unclear. It has been proposed that cadmium activates transcription by altering intracellular calcium concentration ([Ca(2+)](i)) and disrupting calcium-mediated intracellular signaling processes. This hypothesis is based on several studies that may be technically problematic; including the use of BAPTA chelators, BAPTA-based fluorescent sensors, and cytotoxic concentrations of metal. METHODOLOGY/PRINCIPAL FINDING In the present report, the effects of cadmium on [Ca(2+)](i) under non-cytotoxic and cytotoxic conditions was monitored using the protein-based calcium sensor yellow cameleon (YC3.60), which was stably expressed in HEK293 cells. In HEK293 constitutively expressing YC3.60, this calcium sensor was found to be insensitive to cadmium. Exposing HEK293::YC3.60 cells to non-cytotoxic cadmium concentrations was sufficient to induce transcription of cadmium-responsive genes but did not affect [Ca(2+)](i) mobilization or increase steady-state mRNA levels of calcium-responsive genes. In contrast, exposure to cytotoxic concentrations of cadmium significantly reduced intracellular calcium stores and altered calcium-responsive gene expression. CONCLUSIONS/SIGNIFICANCE These data indicate that at low levels, cadmium induces transcription independently of intracellular calcium mobilization. The results also support a model whereby cytotoxic levels of cadmium activate calcium-responsive transcription as a general response to metal-induced intracellular damage and not via a specific mechanism. Thus, the modulation of intracellular calcium may not be a primary mechanism by which cadmium regulates transcription.
Collapse
Affiliation(s)
- Brooke E. Tvermoes
- Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health (NIH), Research Triangle Park, North Carolina, United States of America
- Nicholas School of the Environment, Duke University, Durham, North Carolina, United States of America
| | - Gary S. Bird
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health (NIH), Research Triangle Park, North Carolina, United States of America
| | - Jonathan H. Freedman
- Laboratory of Toxicology and Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health (NIH), Research Triangle Park, North Carolina, United States of America
- * E-mail:
| |
Collapse
|
187
|
Zhang Y, Dong L, Yang X, Shi H, Zhang L. α-Linolenic acid prevents endoplasmic reticulum stress-mediated apoptosis of stearic acid lipotoxicity on primary rat hepatocytes. Lipids Health Dis 2011; 10:81. [PMID: 21592363 PMCID: PMC3112425 DOI: 10.1186/1476-511x-10-81] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Accepted: 05/18/2011] [Indexed: 12/17/2022] Open
Abstract
Aims Lipid accumulation in non-adipose tissues leads to cell dysfunction and apoptosis, a phenomenon known as lipotoxicity. Unsaturated fatty acids may offset the lipotoxicity associated with saturated fatty acids. Stearic acid induced endoplasmic reticulum (ER) stress and caused apoptotic and necrotic cell death in the primary rat hepatocytes. Methods Cell viability was investigated using MTT assay, and apoptosis was evaluated with Hoechst 33342 staining. Western blot analysis was used to examine the changes in the expression levels of glucose regulated protein 78 (GRP78), glucose regulated protein 94 (GRP94), and C/EBP homologous protein (CHOP). Caspase-3 activity was evaluated using a Caspase-3 substrate kit. Results We have studied the ability of α-linolenic acid to prevent endoplasmic reticulum stress-mediated apoptosis of rat hepatocytes elicited by stearic acid and thapsigargin. Incubation of primary rat hepatocytes for 16 h with stearic acid produced a significant increase in cell death. Stearic acid also increased levels of three indicators of ER stress -- GRP78, CHOP, and GRP94. α-Linolenic acid distinctly reduced cell death and levels of all three indicators of ER stress brought about by stearic acid. Thapsigargin, which induces ER stress produced similar effects to those obtained using stearic acid; its effects were partly reversed by α-linolenic acid. Conclusion These results suggest that α-linolenic acid prevents ER stress-mediated apoptosis of stearic acid lipotoxicity on primary rat hepatocytes might become a target to develop new antiapoptotic compounds in nonalcoholic fatty liver disease (NAFLD).
Collapse
Affiliation(s)
- Yong Zhang
- Department of Gastroenterology, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province-710004, China
| | | | | | | | | |
Collapse
|
188
|
Arbabian A, Brouland JP, Gélébart P, Kovàcs T, Bobe R, Enouf J, Papp B. Endoplasmic reticulum calcium pumps and cancer. Biofactors 2011; 37:139-49. [PMID: 21674635 DOI: 10.1002/biof.142] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Accepted: 12/15/2010] [Indexed: 12/11/2022]
Abstract
Endoplasmic reticulum calcium homeostasis is involved in a multitude of signaling, as well as "house-keeping" functions that control cell growth, differentiation or apoptosis in every human/eukaryotic cell. Calcium is actively accumulated in the endoplasmic reticulum by Sarco/Endoplasmic Reticulum Calcium transport ATPases (SERCA enzymes). SERCA-dependent calcium transport is the only calcium uptake mechanism in this organelle, and therefore the regulation of SERCA function by the cell constitutes a key mechanism to adjust calcium homeostasis in the endoplasmic reticulum depending on the cell type and its state of differentiation. The direct pharmacological modulation of SERCA activity affects cell differentiation and survival. SERCA expression levels can undergo significant changes during cell differentiation or tumorigenesis, leading to modified endoplasmic reticulum calcium storage. In several cell types such as cells of hematopoietic origin or various epithelial cells, two SERCA genes (SERCA2 and SERCA3) are simultaneously expressed. Expression levels of SERCA3, a lower calcium affinity calcium pump are highly variable. In several cell systems SERCA3 expression is selectively induced during differentiation, whereas during tumorigenesis and blastic transformation SERCA3 expression is decreased. These observations point at the existence of a cross-talk, via the regulation of SERCA3 levels, between endoplasmic reticulum calcium homeostasis and the control of cell differentiation, and show that endoplasmic reticulum calcium homeostasis itself can undergo remodeling during differentiation. The investigation of the anomalies of endoplasmic reticulum differentiation in tumor and leukemia cells may be useful for a better understanding of the contribution of calcium signaling to the establishment of malignant phenotypes.
Collapse
Affiliation(s)
- Atousa Arbabian
- Institut National de la Santé et de la Recherche Médicale, Inserm UMR-S, Institut Universitaire d'Hématologie, Université Paris Diderot-Paris, France
| | | | | | | | | | | | | |
Collapse
|
189
|
Guerra FM, Moreno-Dorado FJ, Jorge ZD, Massanet GM. Recent Advances in the Synthesis of Sesquiterpenolides from Umbelliferae. Nat Prod Commun 2011. [DOI: 10.1177/1934578x1100600409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
A review of our latest developments in the synthesis of sesquiterpenolides isolated from plants of the Umbelliferae family is presented.
Collapse
Affiliation(s)
- Francisco M. Guerra
- Departamento de Química Orgánica, Universidad de Cádiz, Facultad de Ciencias, Pol. Río San Pedro s/n, 11510 Puerto Real, Cádiz, Spain
| | - F. Javier Moreno-Dorado
- Departamento de Química Orgánica, Universidad de Cádiz, Facultad de Ciencias, Pol. Río San Pedro s/n, 11510 Puerto Real, Cádiz, Spain
| | - Zacarías D. Jorge
- Departamento de Química Orgánica, Universidad de Cádiz, Facultad de Ciencias, Pol. Río San Pedro s/n, 11510 Puerto Real, Cádiz, Spain
| | - Guillermo M. Massanet
- Departamento de Química Orgánica, Universidad de Cádiz, Facultad de Ciencias, Pol. Río San Pedro s/n, 11510 Puerto Real, Cádiz, Spain
| |
Collapse
|
190
|
Nelson HM, Murakami K, Virgil SC, Stoltz BM. A General Approach to the Basiliolide/Transtaganolide Natural Products: Total Syntheses of Basiliolide B, epi-8-Basiliolide B, Transtaganolide C, and Transtaganolide D. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201008003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
191
|
Nelson HM, Murakami K, Virgil SC, Stoltz BM. A general approach to the basiliolide/transtaganolide natural products: total syntheses of basiliolide B, epi-8-basiliolide B, transtaganolide C, and transtaganolide D. Angew Chem Int Ed Engl 2011; 50:3688-91. [PMID: 21442697 DOI: 10.1002/anie.201008003] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2010] [Indexed: 11/06/2022]
Affiliation(s)
- Hosea M Nelson
- Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, Caltech Center for Catalysis and Chemical Synthesis, California Institute of Technology, 1200 E. California Boulevard, MC 101-20, Pasadena, CA 91125, USA
| | | | | | | |
Collapse
|
192
|
Elam C, Lape M, Deye J, Zultowsky J, Stanton DT, Paula S. Discovery of novel SERCA inhibitors by virtual screening of a large compound library. Eur J Med Chem 2011; 46:1512-23. [PMID: 21353727 DOI: 10.1016/j.ejmech.2011.01.069] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 12/10/2010] [Accepted: 01/29/2011] [Indexed: 01/07/2023]
Abstract
Two screening protocols based on recursive partitioning and computational ligand docking methodologies, respectively, were employed for virtual screens of a compound library with 345,000 entries for novel inhibitors of the enzyme sarco/endoplasmic reticulum calcium ATPase (SERCA), a potential target for cancer chemotherapy. A total of 72 compounds that were predicted to be potential inhibitors of SERCA were tested in bioassays and 17 displayed inhibitory potencies at concentrations below 100 μM. The majority of these inhibitors were composed of two phenyl rings tethered to each other by a short link of one to three atoms. Putative interactions between SERCA and the inhibitors were identified by inspection of docking-predicted poses and some of the structural features required for effective SERCA inhibition were determined by analysis of the classification pattern employed by the recursive partitioning models.
Collapse
Affiliation(s)
- Christopher Elam
- Department of Chemistry, Northern Kentucky University, Highland Heights, KY 41099-1905, USA
| | | | | | | | | | | |
Collapse
|
193
|
Li GW, Wang QS, Hao JH, Xing WJ, Guo J, Li HZ, Bai SZ, Li HX, Zhang WH, Yang BF, Yang GD, Wu LY, Wang R, Xu CQ. The functional expression of extracellular calcium-sensing receptor in rat pulmonary artery smooth muscle cells. J Biomed Sci 2011; 18:16. [PMID: 21314926 PMCID: PMC3050794 DOI: 10.1186/1423-0127-18-16] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Accepted: 02/11/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The extracellular calcium-sensing receptor (CaSR) belongs to family C of the G protein coupled receptors. Whether the CaSR is expressed in the pulmonary artery (PA) is unknown. METHODS The expression and distribution of CaSR were detected by RT-PCR, Western blotting and immunofluorescence. PA tension was detected by the pulmonary arterial ring technique, and the intracellular calcium concentration ([Ca2+]i) was detected by a laser-scanning confocal microscope. RESULTS The expressions of CaSR mRNA and protein were found in both rat pulmonary artery smooth muscle cells (PASMCs) and PAs. Increased levels of [Ca2+]o (extracellular calcium concentration) or Gd3+ (an agonist of CaSR) induced an increase of [Ca2+]i and PAs constriction in a concentration-dependent manner. In addition, the above-mentioned effects of Ca2+ and Gd3+ were inhibited by U73122 (specific inhibitor of PLC), 2-APB (specific antagonist of IP3 receptor), and thapsigargin (blocker of sarcoplasmic reticulum calcium ATPase). CONCLUSIONS CaSR is expressed in rat PASMCs, and is involved in regulation of PA tension by increasing [Ca2+]i through G-PLC-IP3 pathway.
Collapse
Affiliation(s)
- Guang-wei Li
- Department of Pathophysiology, Qiqihar Medical University, Qiqihar 161006, PR China
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
194
|
Nejime N, Tada Y, Kagota S, Kubota Y, Shibuichi I, Shinoda Y, Yamamoto T, Watanabe Y, Shinozuka K. Effect of vanadate on ATP-induced increase in intracellular calcium ion levels in human umbilical vein endothelial cells. Biol Pharm Bull 2011; 33:1060-2. [PMID: 20522978 DOI: 10.1248/bpb.33.1060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated the effect of ammonium vanadate (vanadate) on ATP-induced increases in intracellular calcium ion level ([Ca(2+)](i)) of human umbilical vein endothelial cells (HUVEC) by fluorescence confocal microscopic imaging using the Ca(2+)-sensitive probe Calcium Green 1/AM. The ATP analogue 2-methylthio-ATP (2meS-ATP), at 10 microM, significantly increased the [Ca(2+)](i) of HUVEC, and this was abolished by 1 microM thapsigargin (a calcium pump inhibitor), whereas extracellular free calcium had no effect. Vanadate at 10 microM also significantly increased the [Ca(2+)](i) of HUVEC, which was abolished by 1 microM thapsigargin. However, vanadate at 1 microM did not exert such a significant effect. We thus examined the influence of < or =1 microM vanadate for 24 h on 2meS-ATP-induced increase in [Ca(2+)](i). Vanadate significantly reduced the action of 2meS-ATP at 1 microM but not at 0.1 microM. Endogenously released ATP is known to induce various actions on endothelial cells. The present results suggest that vanadate exerts a regulatory influence on the function of vascular endothelial cells.
Collapse
Affiliation(s)
- Namie Nejime
- Department of Pharmacology, School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women's University, Nishinomiya, Hyogo 663-8179, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
195
|
Zhong Q, Zhou B, Ann DK, Minoo P, Liu Y, Banfalvi A, Krishnaveni MS, Dubourd M, Demaio L, Willis BC, Kim KJ, duBois RM, Crandall ED, Beers MF, Borok Z. Role of endoplasmic reticulum stress in epithelial-mesenchymal transition of alveolar epithelial cells: effects of misfolded surfactant protein. Am J Respir Cell Mol Biol 2010; 45:498-509. [PMID: 21169555 DOI: 10.1165/rcmb.2010-0347oc] [Citation(s) in RCA: 149] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Endoplasmic reticulum (ER) stress has been implicated in alveolar epithelial type II (AT2) cell apoptosis in idiopathic pulmonary fibrosis. We hypothesized that ER stress (either chemically induced or due to accumulation of misfolded proteins) is also associated with epithelial-mesenchymal transition (EMT) in alveolar epithelial cells (AECs). ER stress inducers, thapsigargin (TG) or tunicamycin (TN), increased expression of ER chaperone, Grp78, and spliced X-box binding protein 1, decreased epithelial markers, E-cadherin and zonula occludens-1 (ZO-1), increased the myofibroblast marker, α-smooth muscle actin (α-SMA), and induced fibroblast-like morphology in both primary AECs and the AT2 cell line, RLE-6TN, consistent with EMT. Overexpression of the surfactant protein (SP)-C BRICHOS mutant SP-C(ΔExon4) in A549 cells increased Grp78 and α-SMA and disrupted ZO-1 distribution, and, in primary AECs, SP-C(ΔExon4) induced fibroblastic-like morphology, decreased ZO-1 and E-cadherin and increased α-SMA, mechanistically linking ER stress associated with mutant SP to fibrosis through EMT. Whereas EMT was evident at lower concentrations of TG or TN, higher concentrations caused apoptosis. The Src inhibitor, 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4]pyramidine) (PP2), abrogated EMT associated with TN or TG in primary AECs, whereas overexpression of SP-C(ΔExon4) increased Src phosphorylation, suggesting a common mechanism. Furthermore, increased Grp78 immunoreactivity was observed in AT2 cells of mice after bleomycin injury, supporting a role for ER stress in epithelial abnormalities in fibrosis in vivo. These results demonstrate that ER stress induces EMT in AECs, at least in part through Src-dependent pathways, suggesting a novel role for ER stress in fibroblast accumulation in pulmonary fibrosis.
Collapse
Affiliation(s)
- Qian Zhong
- Will Rogers Institute Pulmonary Research Center, Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Southern California, Keck School of Medicine, Los Angeles, CA 90033, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
196
|
Hiratsuka T, Matsuzaki S, Miyata S, Kinoshita M, Kakehi K, Nishida S, Katayama T, Tohyama M. Yokukansan inhibits neuronal death during ER stress by regulating the unfolded protein response. PLoS One 2010; 5:e13280. [PMID: 20967273 PMCID: PMC2953506 DOI: 10.1371/journal.pone.0013280] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Accepted: 09/05/2010] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Recently, several studies have reported Yokukansan (Tsumura TJ-54), a traditional Japanese medicine, as a potential new drug for the treatment of Alzheimer's disease (AD). Endoplasmic reticulum (ER) stress is known to play an important role in the pathogenesis of AD, particularly in neuronal death. Therefore, we examined the effect of Yokukansan on ER stress-induced neurotoxicity and on familial AD-linked presenilin-1 mutation-associated cell death. METHODS We employed the WST-1 assay and monitored morphological changes to evaluate cell viability following Yokukansan treatment or treatment with its components. Western blotting and PCR were used to observe the expression levels of GRP78/BiP, caspase-4 and C/EBP homologous protein. RESULTS Yokukansan inhibited neuronal death during ER stress, with Cnidii Rhizoma (Senkyu), a component of Yokukansan, being particularly effective. We also showed that Yokukansan and Senkyu affect the unfolded protein response following ER stress and that these drugs inhibit the activation of caspase-4, resulting in the inhibition of ER stress-induced neuronal death. Furthermore, we found that the protective effect of Yokukansan and Senkyu against ER stress could be attributed to the ferulic acid content of these two drugs. CONCLUSIONS Our results indicate that Yokukansan, Senkyu and ferulic acid are protective against ER stress-induced neuronal cell death and may provide a possible new treatment for AD.
Collapse
Affiliation(s)
- Toru Hiratsuka
- Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Shinsuke Matsuzaki
- Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, Kanazawa University and Hamamatsu University School of Medicine, Suita, Japan
- The Osaka-Hamamatsu Joint Research Center for Child Mental Development, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Shingo Miyata
- Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
- The Osaka-Hamamatsu Joint Research Center for Child Mental Development, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Mitsuhiro Kinoshita
- Laboratory of Biopharmaco Informatics, School of Pharmaceutical Sciences, Kinki University, Higashiosaka, Japan
| | - Kazuaki Kakehi
- Laboratory of Biopharmaco Informatics, School of Pharmaceutical Sciences, Kinki University, Higashiosaka, Japan
| | - Shinji Nishida
- Department of Kampo Medicine, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Taiichi Katayama
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, Kanazawa University and Hamamatsu University School of Medicine, Suita, Japan
| | - Masaya Tohyama
- Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, Kanazawa University and Hamamatsu University School of Medicine, Suita, Japan
- The Osaka-Hamamatsu Joint Research Center for Child Mental Development, Graduate School of Medicine, Osaka University, Suita, Japan
| |
Collapse
|
197
|
Schwarzer C, Wong S, Shi J, Matthes E, Illek B, Ianowski JP, Arant RJ, Isacoff E, Vais H, Foskett JK, Maiellaro I, Hofer AM, Machen TE. Pseudomonas aeruginosa Homoserine lactone activates store-operated cAMP and cystic fibrosis transmembrane regulator-dependent Cl- secretion by human airway epithelia. J Biol Chem 2010; 285:34850-63. [PMID: 20739289 DOI: 10.1074/jbc.m110.167668] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The ubiquitous bacterium Pseudomonas aeruginosa frequently causes hospital-acquired infections. P. aeruginosa also infects the lungs of cystic fibrosis (CF) patients and secretes N-(3-oxo-dodecanoyl)-S-homoserine lactone (3O-C12) to regulate bacterial gene expression critical for P. aeruginosa persistence. In addition to its effects as a quorum-sensing gene regulator in P. aeruginosa, 3O-C12 elicits cross-kingdom effects on host cell signaling leading to both pro- or anti-inflammatory effects. We find that in addition to these slow effects mediated through changes in gene expression, 3O-C12 also rapidly increases Cl(-) and fluid secretion in the cystic fibrosis transmembrane regulator (CFTR)-expressing airway epithelia. 3O-C12 does not stimulate Cl(-) secretion in CF cells, suggesting that lactone activates the CFTR. 3O-C12 also appears to directly activate the inositol trisphosphate receptor and release Ca(2+) from the endoplasmic reticulum (ER), lowering [Ca(2+)] in the ER and thereby activating the Ca(2+)-sensitive ER signaling protein STIM1. 3O-C12 increases cytosolic [Ca(2+)] and, strikingly, also cytosolic [cAMP], the known activator of CFTR. Activation of Cl(-) current by 3O-C12 was inhibited by a cAMP antagonist and increased by a phosphodiesterase inhibitor. Finally, a Ca(2+) buffer that lowers [Ca(2+)] in the ER similar to the effect of 3O-C12 also increased cAMP and I(Cl). The results suggest that 3O-C12 stimulates CFTR-dependent Cl(-) and fluid secretion in airway epithelial cells by activating the inositol trisphosphate receptor, thus lowering [Ca(2+)] in the ER and activating STIM1 and store-operated cAMP production. In CF airways, where CFTR is absent, the adaptive ability to rapidly flush the bacteria away is compromised because the lactone cannot affect Cl(-) and fluid secretion.
Collapse
Affiliation(s)
- Christian Schwarzer
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3200, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
198
|
An Apparent Paradox: Attenuation of Phenylephrine-mediated Calcium Mobilization and Hyperreactivity to Phenylephrine in Contralateral Carotid After Balloon Injury. J Cardiovasc Pharmacol 2010; 56:162-70. [DOI: 10.1097/fjc.0b013e3181e571cd] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
199
|
Gehrig-Burger K, Slaninova J, Gimpl G. Depletion of calcium stores contributes to progesterone-induced attenuation of calcium signaling of G protein-coupled receptors. Cell Mol Life Sci 2010; 67:2815-24. [PMID: 20376529 PMCID: PMC11115651 DOI: 10.1007/s00018-010-0360-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Revised: 03/15/2010] [Accepted: 03/18/2010] [Indexed: 10/19/2022]
Abstract
Progesterone non-genomically attenuates the calcium signaling of the human oxytocin receptor and several other Galpha(q) protein-coupled receptors. High progesterone concentrations are found in the endometrium during pregnancy opposing the responsiveness of the underlying myometrium to labor-inducing hormones. Here, we demonstrate that within minutes, progesterone inhibits oxytocin- and bradykinin-induced contractions of rat uteri, calcium responses induced by platelet-activating factor in the human endometrial cell line MFE-280, and oxytocin-induced calcium signals in PHM1-31 immortalized pregnant human myometrial cells. Using human embryonic kidney (HEK293) cells as model system, we analyzed the molecular mechanisms underlying these effects. Our data indicate that progesterone rapidly depletes intracellular calcium stores. The resulting desensitization of the cells might contribute to the quiescence of the uterus during pregnancy.
Collapse
Affiliation(s)
- Katja Gehrig-Burger
- Institute of Pharmaceutics and Biochemistry, University of Mainz, 55099 Mainz, Germany.
| | | | | |
Collapse
|
200
|
Comparison of current docking tools for the simulation of inhibitor binding by the transmembrane domain of the sarco/endoplasmic reticulum calcium ATPase. Biophys Chem 2010. [DOI: 10.1016/j.bpc.2010.01.011 pmid: 20167416] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
|