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Adomako-Bonsu AG, Jacobsen J, Maser E. Metabolic activation of 2,4,6-trinitrotoluene; a case for ROS-induced cell damage. Redox Biol 2024; 72:103082. [PMID: 38527399 PMCID: PMC10979124 DOI: 10.1016/j.redox.2024.103082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/07/2024] [Accepted: 02/08/2024] [Indexed: 03/27/2024] Open
Abstract
The explosive compound 2,4,6-trinitrotoluene (TNT) is well known as a major component of munitions. In addition to its potential carcinogenicity and mutagenicity in humans, recent reports have highlighted TNT toxicities in diverse organisms due to its occurrence in the environment. These toxic effects have been linked to the intracellular metabolism of TNT, which is generally characterised by redox cycling and the generation of noxious reactive molecules. The reactive intermediates formed, such as nitroso and hydroxylamine compounds, also interact with oxygen molecules and cellular components to cause macromolecular damage and oxidative stress. The current review aims to highlight the crucial role of TNT metabolism in mediating TNT toxicity, via increased generation of reactive oxygen species. Cellular proliferation of reactive species results in depletion of cellular antioxidant enzymes, DNA and protein adduct formation, and oxidative stress. While TNT toxicity is well known, its ability to induce oxidative stress, resulting from its reductive activation, suggests that some of its toxic effects may be caused by its reactive metabolites. Hence, further research on TNT metabolism is imperative to elucidate TNT-induced toxicities.
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Affiliation(s)
- Amma Gyapomah Adomako-Bonsu
- Institute of Toxicology and Pharmacology for Natural Scientists, University Medical School Schleswig-Holstein Campus Kiel, Brunswiker Str. 10, 24105, Kiel, Germany
| | - Jana Jacobsen
- Institute of Toxicology and Pharmacology for Natural Scientists, University Medical School Schleswig-Holstein Campus Kiel, Brunswiker Str. 10, 24105, Kiel, Germany
| | - Edmund Maser
- Institute of Toxicology and Pharmacology for Natural Scientists, University Medical School Schleswig-Holstein Campus Kiel, Brunswiker Str. 10, 24105, Kiel, Germany.
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Negri S, Faris P, Moccia F. Reactive Oxygen Species and Endothelial Ca 2+ Signaling: Brothers in Arms or Partners in Crime? Int J Mol Sci 2021; 22:ijms22189821. [PMID: 34575985 PMCID: PMC8465413 DOI: 10.3390/ijms22189821] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/08/2021] [Accepted: 09/08/2021] [Indexed: 12/20/2022] Open
Abstract
An increase in intracellular Ca2+ concentration ([Ca2+]i) controls virtually all endothelial cell functions and is, therefore, crucial to maintain cardiovascular homeostasis. An aberrant elevation in endothelial can indeed lead to severe cardiovascular disorders. Likewise, moderate amounts of reactive oxygen species (ROS) induce intracellular Ca2+ signals to regulate vascular functions, while excessive ROS production may exploit dysregulated Ca2+ dynamics to induce endothelial injury. Herein, we survey how ROS induce endothelial Ca2+ signals to regulate vascular functions and, vice versa, how aberrant ROS generation may exploit the Ca2+ handling machinery to promote endothelial dysfunction. ROS elicit endothelial Ca2+ signals by regulating inositol-1,4,5-trisphosphate receptors, sarco-endoplasmic reticulum Ca2+-ATPase 2B, two-pore channels, store-operated Ca2+ entry (SOCE), and multiple isoforms of transient receptor potential (TRP) channels. ROS-induced endothelial Ca2+ signals regulate endothelial permeability, angiogenesis, and generation of vasorelaxing mediators and can be exploited to induce therapeutic angiogenesis, rescue neurovascular coupling, and induce cancer regression. However, an increase in endothelial [Ca2+]i induced by aberrant ROS formation may result in endothelial dysfunction, inflammatory diseases, metabolic disorders, and pulmonary artery hypertension. This information could pave the way to design alternative treatments to interfere with the life-threatening interconnection between endothelial ROS and Ca2+ signaling under multiple pathological conditions.
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Bae H, You S, Lim W, Song G. Pyridaben leads to inhibition of cell growth and induction of cell death through intracellular mechanisms in early pregnancy. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2021; 171:104733. [PMID: 33357555 DOI: 10.1016/j.pestbp.2020.104733] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 09/08/2020] [Accepted: 10/12/2020] [Indexed: 06/12/2023]
Abstract
Recently, infertility has become a major global issue. It is crucial to identify environmental factors that lead to infertility. The prevalent use of pesticides in agriculture results in the exposure of livestock and humans to these pesticides. Studies have reported the harmful effects of pesticides on pregnancy. Pyridaben, a pesticide that inhibits mitochondrial complex 1, has been reported to have detrimental effects on neurons, spermatogenesis, hormonal balance, and embryonic development. However, the effect of pyridaben on the female reproductive system has not yet been studied. Therefore, in this study, we evaluated the effects of pyridaben on early pregnancy in porcine reproductive cell lines, which are known to mimic the female reproductive system. Results demonstrated that pyridaben decreased cell growth in porcine endometrial luminal epithelial and porcine trophectoderm cell lines through inhibition of cell signal transduction. Further, pyridaben increased subG1 phase and late apoptosis through the induction of reactive oxygen species production, mitochondrial dysfunction, calcium unbalances, pro-apoptotic signals, and endoplasmic reticulum (ER) stress. Moreover, we found that pyridaben induced autophagy and inhibition of placentation through the regulation of ER-mitochondria axis proteins. Overall, pyridaben was found to be harmful in early pregnancy in pigs and may have similar effects in human pregnancy.
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Affiliation(s)
- Hyocheol Bae
- Institute of Animal Molecular Biotechnology and Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Seungkwon You
- Institute of Animal Molecular Biotechnology and Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea.
| | - Whasun Lim
- Department of Food and Nutrition, Kookmin University, Seoul 02707, Republic of Korea.
| | - Gwonhwa Song
- Institute of Animal Molecular Biotechnology and Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea.
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4
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He P, Talukder MAH, Gao F. Oxidative Stress and Microvessel Barrier Dysfunction. Front Physiol 2020; 11:472. [PMID: 32536875 PMCID: PMC7268512 DOI: 10.3389/fphys.2020.00472] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Accepted: 04/17/2020] [Indexed: 12/11/2022] Open
Abstract
Clinical and experimental evidence indicate that increased vascular permeability contributes to many disease-associated vascular complications. Oxidative stress with increased production of reactive oxygen species (ROS) has been implicated in a wide variety of pathological conditions, including inflammation and many cardiovascular diseases. It is thus important to identify the role of ROS and their mechanistic significance in microvessel barrier dysfunction under pathological conditions. The role of specific ROS and their cross talk in pathological processes is complex. The mechanisms of ROS-induced increases in vascular permeability remain poorly understood. The sources of ROS in diseases have been extensively reviewed at enzyme levels. This review will instead focus on the underlying mechanisms of ROS release by leukocytes, the differentiate effects and signaling mechanisms of individual ROS on endothelial cells, pericytes and microvessel barrier function, as well as the interplay of reactive oxygen species, nitric oxide, and nitrogen species in ROS-mediated vascular barrier dysfunction. As a counter balance of excessive ROS, nuclear factor erythroid 2 related factor 2 (Nrf2), a redox-sensitive cell-protective transcription factor, will be highlighted as a potential therapeutic target for antioxidant defenses. The advantages and limitations of different experimental approaches used for the study of ROS-induced endothelial barrier function are also discussed. This article will outline the advances emerged mainly from in vivo and ex vivo studies and attempt to consolidate some of the opposing views in the field, and hence provide a better understanding of ROS-mediated microvessel barrier dysfunction and benefit the development of therapeutic strategies.
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Affiliation(s)
- Pingnian He
- Department of Cellular and Molecular Physiology, College of Medicine, The Pennsylvania State University, Hershey, PA, United States
| | - M A Hassan Talukder
- Department of Cellular and Molecular Physiology, College of Medicine, The Pennsylvania State University, Hershey, PA, United States
| | - Feng Gao
- Department of Cellular and Molecular Physiology, College of Medicine, The Pennsylvania State University, Hershey, PA, United States
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5
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Zhang X, Lee MD, Wilson C, McCarron JG. Hydrogen peroxide depolarizes mitochondria and inhibits IP 3-evoked Ca 2+ release in the endothelium of intact arteries. Cell Calcium 2019; 84:102108. [PMID: 31715384 PMCID: PMC6891240 DOI: 10.1016/j.ceca.2019.102108] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 08/30/2019] [Accepted: 10/30/2019] [Indexed: 12/30/2022]
Abstract
H2O2 is produced by several cell processes including mitochondria and may act as an intracellular messenger and cell-cell signalling molecule. Spontaneous local Ca2+ signals and IP3-evoked Ca2+ increases were inhibited by H2O2. H2O2 suppression of IP3-evoked Ca2+ signalling may be mediated by mitochondria via a decrease in the mitochondrial membrane potential. H2O2-induced mitochondrial depolarization and inhibition of IP3-evoked Ca2+ release, may protect mitochondria from Ca2+ overload during IP3-linked Ca2+ signals.
Hydrogen peroxide (H2O2) is a mitochondrial-derived reactive oxygen species (ROS) that regulates vascular signalling transduction, vasocontraction and vasodilation. Although the physiological role of ROS in endothelial cells is acknowledged, the mechanisms underlying H2O2 regulation of signalling in native, fully-differentiated endothelial cells is unresolved. In the present study, the effects of H2O2 on Ca2+ signalling were investigated in the endothelium of intact rat mesenteric arteries. Spontaneous local Ca2+ signals and acetylcholine evoked Ca2+ increases were inhibited by H2O2. H2O2 inhibition of acetylcholine-evoked Ca2+ signals was reversed by catalase. H2O2 exerts its inhibition on the IP3 receptor as Ca2+ release evoked by photolysis of caged IP3 was supressed by H2O2. H2O2 suppression of IP3-evoked Ca2+ signalling may be mediated by mitochondria. H2O2 depolarized mitochondria membrane potential. Acetylcholine-evoked Ca2+ release was inhibited by depolarisation of the mitochondrial membrane potential by the uncoupler carbonyl cyanide 3-chlorophenylhydrazone (CCCP) or complex 1 inhibitor, rotenone. We propose that the suppression of IP3-evoked Ca2+ release by H2O2 arises from the decrease in mitochondrial membrane potential. These results suggest that mitochondria may protect themselves against Ca2+ overload during IP3-linked Ca2+ signals by a H2O2 mediated negative feedback depolarization of the organelle and inhibition of IP3-evoked Ca2+ release.
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Affiliation(s)
- Xun Zhang
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK
| | - Matthew D Lee
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK
| | - Calum Wilson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK
| | - John G McCarron
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK.
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Park H, Lim W, You S, Song G. Fenbendazole induces apoptosis of porcine uterine luminal epithelial and trophoblast cells during early pregnancy. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 681:28-38. [PMID: 31102815 DOI: 10.1016/j.scitotenv.2019.05.116] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/07/2019] [Accepted: 05/08/2019] [Indexed: 06/09/2023]
Abstract
Fenbendazole, is an effective benzimidazole anthelmintic that prevents parasite infection in both human and veterinary health care. Although the well-known and effect of benzimidazole was recently shown to have a broad spectrum of biological abilities, such as anticancer and anti-inflammation activities, the mechanism of benzimidazole's antiproliferative effect via cell signaling pathways and its role in preimplantation has not been studied. Therefore, the purpose of this study was to determine the effects of fenbendazole on porcine trophectoderm and luminal epithelial cells. First, we investigated cell viability in response to a low dose of fenbendazole, which highly inhibited cell proliferation. In addition, we investigated apoptotic molecules in the mitochondria, imbalanced intracellular calcium homeostasis, and the expression of some genes involved in apoptosis to explain the decrease in proliferation. Finally, we examined the intracellular mechanisms of fenbendazole by measuring the extracellular signal-regulated kinase, PI3K/AKT, and c-Jun N-terminal kinase signaling proteins by western blot analysis. Our findings suggest that fenbendazole functions as an effective anti-proliferative molecule that induces critical apoptosis in the porcine trophectoderm and uterine luminal epithelial cells by disrupting the mitochondria membrane potential during early pregnancy.
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Affiliation(s)
- Hahyun Park
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Whasun Lim
- Department of Food and Nutrition, Kookmin University, Seoul 02707, Republic of Korea
| | - Seungkwon You
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea.
| | - Gwonhwa Song
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea.
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VAS2870 Inhibits Histamine-Induced Calcium Signaling and vWF Secretion in Human Umbilical Vein Endothelial Cells. Cells 2019; 8:cells8020196. [PMID: 30813397 PMCID: PMC6406370 DOI: 10.3390/cells8020196] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 02/15/2019] [Accepted: 02/22/2019] [Indexed: 12/15/2022] Open
Abstract
In this study, we investigated the effects of NAD(P)H oxidase (NOX) inhibitor VAS2870 (3-benzyl-7-(2-benzoxazolyl)thio-1,2,3-triazolo[4,5-d]pyrimidine) on the histamine-induced elevation of free cytoplasmic calcium concentration ([Ca2+]i) and the secretion of von Willebrand factor (vWF) in human umbilical vein endothelial cells (HUVECs) and on relaxation of rat aorta in response to histamine. At 10 μM concentration, VAS2870 suppressed the [Ca2+]i rise induced by histamine. Inhibition was not competitive, with IC50 3.64 and 3.22 μM at 1 and 100 μM concentrations of histamine, respectively. There was no inhibition of [Ca2+]i elevation by VAS2870 in HUVECs in response to the agonist of type 1 protease-activated receptor SFLLRN. VAS2870 attenuated histamine-induced secretion of vWF and did not inhibit basal secretion. VAS2870 did not change the degree of histamine-induced relaxation of rat aortic rings constricted by norepinephrine. We suggest that NOX inhibitors might be used as a tool for preventing thrombosis induced by histamine release from mast cells without affecting vasorelaxation.
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Enhancement by Hydrogen Peroxide of Calcium Signals in Endothelial Cells Induced by 5-HT1B and 5-HT2B Receptor Agonists. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:1701478. [PMID: 30886671 PMCID: PMC6388333 DOI: 10.1155/2019/1701478] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 11/29/2018] [Accepted: 12/10/2018] [Indexed: 01/06/2023]
Abstract
Hydrogen peroxide, formed in the endothelium, acts as a factor contributing to the relaxation of blood vessels. The reason for this vasodilatory effect could be modulation by H2O2 of calcium metabolism, since mobilization of calcium ions in endothelial cells is a trigger of endothelium-dependent relaxation. The aim of this work was to investigate the influence of H2O2 on the effects of Ca2+-mobilizing agonists in human umbilical vein endothelial cells (HUVEC). We have found that H2O2 in concentration range 10-100 μM increases the rise of [Ca2+]i induced by 5-hydroxytryptamine (5-HT) and carbachol and does not affect the calcium signals of ATP, agonist of type 1 protease-activated receptor SFLLRN, histamine and bradykinin. Using specific agonists of 5-HT1B and 5-HT2B receptors CGS12066B and BW723C86, we have demonstrated that H2O2 potentiates the effects mediated by these types of 5-HT receptors. Potentiation of the effect of BW723C86 can be produced by the induction of endogenous oxidative stress in HUVEC. We have shown that the activation of 5-HT2B receptor by BW723C86 causes production of reactive oxygen species (ROS). Inhibitor of NADPH oxidases VAS2870 suppressed formation of ROS and partially inhibited [Ca2+]i rise induced by BW723C86. Thus, it can be assumed that vasorelaxation induced by endogenous H2O2 in endothelial cells partially occurs due to the potentiation of the agonist-induced calcium signaling.
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Choi S, Quan X, Bang S, Yoo H, Kim J, Park J, Park KS, Chung J. Mitochondrial calcium uniporter in Drosophila transfers calcium between the endoplasmic reticulum and mitochondria in oxidative stress-induced cell death. J Biol Chem 2017; 292:14473-14485. [PMID: 28726639 DOI: 10.1074/jbc.m116.765578] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 07/13/2017] [Indexed: 12/16/2022] Open
Abstract
Mitochondrial calcium plays critical roles in diverse cellular processes ranging from energy metabolism to cell death. Previous studies have demonstrated that mitochondrial calcium uptake is mainly mediated by the mitochondrial calcium uniporter (MCU) complex. However, the roles of the MCU complex in calcium transport, signaling, and dysregulation by oxidative stress still remain unclear. Here, we confirmed that Drosophila MCU contains evolutionarily conserved structures and requires essential MCU regulator (EMRE) for its calcium channel activities. We generated Drosophila MCU loss-of-function mutants, which lacked mitochondrial calcium uptake in response to caffeine stimulation. Basal metabolic activities were not significantly affected in these MCU mutants, as observed in examinations of body weight, food intake, body sugar level, and starvation-induced autophagy. However, oxidative stress-induced increases in mitochondrial calcium, mitochondrial membrane potential depolarization, and cell death were prevented in these mutants. We also found that inositol 1,4,5-trisphosphate receptor genetically interacts with Drosophila MCU and effectively modulates mitochondrial calcium uptake upon oxidative stress. Taken together, these results support the idea that Drosophila MCU is responsible for endoplasmic reticulum-to-mitochondrial calcium transfer and for cell death due to mitochondrial dysfunction under oxidative stress.
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Affiliation(s)
- Sekyu Choi
- From the National Creative Research Initiatives Center for Energy Homeostasis Regulation, Institute of Molecular Biology and Genetics and School of Biological Sciences, Seoul National University, Seoul 08826, Korea and
| | - Xianglan Quan
- the Department of Physiology, Yonsei University Wonju College of Medicine, Wonju, Gangwon-Do 26426, Korea
| | - Sunhoe Bang
- From the National Creative Research Initiatives Center for Energy Homeostasis Regulation, Institute of Molecular Biology and Genetics and School of Biological Sciences, Seoul National University, Seoul 08826, Korea and
| | - Heesuk Yoo
- From the National Creative Research Initiatives Center for Energy Homeostasis Regulation, Institute of Molecular Biology and Genetics and School of Biological Sciences, Seoul National University, Seoul 08826, Korea and
| | - Jiyoung Kim
- From the National Creative Research Initiatives Center for Energy Homeostasis Regulation, Institute of Molecular Biology and Genetics and School of Biological Sciences, Seoul National University, Seoul 08826, Korea and
| | - Jiwon Park
- From the National Creative Research Initiatives Center for Energy Homeostasis Regulation, Institute of Molecular Biology and Genetics and School of Biological Sciences, Seoul National University, Seoul 08826, Korea and
| | - Kyu-Sang Park
- the Department of Physiology, Yonsei University Wonju College of Medicine, Wonju, Gangwon-Do 26426, Korea
| | - Jongkyeong Chung
- From the National Creative Research Initiatives Center for Energy Homeostasis Regulation, Institute of Molecular Biology and Genetics and School of Biological Sciences, Seoul National University, Seoul 08826, Korea and
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Blatter LA. Tissue Specificity: SOCE: Implications for Ca 2+ Handling in Endothelial Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 993:343-361. [PMID: 28900923 DOI: 10.1007/978-3-319-57732-6_18] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Many cellular functions of the vascular endothelium are regulated by fine-tuned global and local, microdomain-confined changes of cytosolic free Ca2+ ([Ca2+]i). Vasoactive agonist-induced stimulation of vascular endothelial cells (VECs) typically induces Ca2+ release through IP3 receptor Ca2+ release channels embedded in the membrane of the endoplasmic reticulum (ER) Ca2+ store, followed by Ca2+ entry from the extracellular space elicited by Ca2+ store depletion and referred to as capacitative or store-operated Ca2+ entry (SOCE). In vascular endothelial cells, SOCE is graded with the degree of store depletion and controlled locally in the subcellular microdomain where depletion occurs. SOCE provides distinct Ca2+ signals that selectively control specific endothelial functions: in calf pulmonary artery endothelial cells, the SOCE Ca2+ signal drives nitric oxide (an endothelium-derived relaxing factor of the vascular smooth muscle) production and controls activation and nuclear translocation of the transcription factor NFAT. Both cellular events are not affected by Ca2+ signals of comparable magnitude arising directly from Ca2+ release from intracellular stores, clearly indicating that SOCE regulates specific Ca2+-dependent cellular tasks by a unique and exclusive mechanism. This review discusses the mechanisms of intracellular Ca2+ regulation in vascular endothelial cells and the role of store-operated Ca2+ entry for endothelium-dependent smooth muscle relaxation and nitric oxide signaling, endothelial oxidative stress response, and excitation-transcription coupling in the vascular endothelium.
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Affiliation(s)
- Lothar A Blatter
- Department of Physiology and Biophysics, Rush University Medical Center, 1750 W. Harrison St., Chicago, IL, 60612, USA.
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Bollimuntha S, Pani B, Singh BB. Neurological and Motor Disorders: Neuronal Store-Operated Ca 2+ Signaling: An Overview and Its Function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 993:535-556. [PMID: 28900932 PMCID: PMC5821072 DOI: 10.1007/978-3-319-57732-6_27] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Calcium (Ca2+) is a ubiquitous second messenger that performs significant physiological task such as neurosecretion, exocytosis, neuronal growth/differentiation, and the development and/or maintenance of neural circuits. An important regulatory aspect of neuronal Ca2+ homeostasis is store-operated Ca2+ entry (SOCE) which, in recent years, has gained much attention for influencing a variety of nerve cell responses. Essentially, activation of SOCE ensues following the activation of the plasma membrane (PM) store-operated Ca2+ channels (SOCC) triggered by the depletion of endoplasmic reticulum (ER) Ca2+ stores. In addition to the TRPC (transient receptor potential canonical) and the Orai family of ion channels, STIM (stromal interacting molecule) proteins have been baptized as key molecular regulators of SOCE. Functional significance of the TRPC channels in neurons has been elaborately studied; however, information on Orai and STIM components of SOCE, although seems imminent, is currently limited. Importantly, perturbations in SOCE have been implicated in a spectrum of neuropathological conditions. Hence, understanding the precise involvement of SOCC in neurodegeneration would presumably unveil avenues for plausible therapeutic interventions. We thus review the role of SOCE-regulated neuronal Ca2+ signaling in selecting neurodegenerative conditions.
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Affiliation(s)
- Sunitha Bollimuntha
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58202, USA.
| | - Biswaranjan Pani
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58202, USA
| | - Brij B Singh
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58202, USA.
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Hippophae salicifolia D.Don berries attenuate cerebral ischemia reperfusion injury in a rat model of middle cerebral artery occlusion. JOURNAL OF ACUTE DISEASE 2015. [DOI: 10.1016/s2221-6189(15)30021-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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13
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Kaur G, Bali A, Singh N, Jaggi AS. Ameliorative potential of Ocimum sanctum in chronic constriction injury-induced neuropathic pain in rats. AN ACAD BRAS CIENC 2015; 87:417-29. [PMID: 25673470 DOI: 10.1590/0001-3765201520130008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Accepted: 02/18/2013] [Indexed: 01/23/2023] Open
Abstract
The present study was designed to investigate the ameliorative potential of Ocimum sanctum and its saponin rich fraction in chronic constriction injury-induced neuropathic pain in rats. The chronic constriction injury was induced by placing four loose ligatures around the sciatic nerve, proximal to its trifurcation. The mechanical hyperalgesia, cold allodynia, paw heat hyperalgesia and cold tail hyperalgesia were assessed by performing the pinprick, acetone, hot plate and cold tail immersion tests, respectively. Biochemically, the tissue thio-barbituric acid reactive species, super-oxide anion content (markers of oxidative stress) and total calcium levels were measured. Chronic constriction injury was associated with the development of mechanical hyperalgesia, cold allodynia, heat and cold hyperalgesia along with an increase in oxidative stress and calcium levels. However, administration of Ocimum sanctum (100 and 200 mg/kg p.o.) and its saponin rich fraction (100 and 200 mg/kg p.o.) for 14 days significantly attenuated chronic constriction injury-induced neuropathic pain as well as decrease the oxidative stress and calcium levels. It may be concluded that saponin rich fraction of Ocimum sanctum has ameliorative potential in attenuating painful neuropathic state, which may be attributed to a decrease in oxidative stress and calcium levels.
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Affiliation(s)
- Gurpreet Kaur
- Department of Pharmaceutical Sciences, Punjabi University, Punjab, India
| | - Anjana Bali
- Department of Pharmaceutical Sciences, Punjabi University, Punjab, India
| | - Nirmal Singh
- Department of Pharmaceutical Sciences, Punjabi University, Punjab, India
| | - Amteshwar S Jaggi
- Department of Pharmaceutical Sciences, Punjabi University, Punjab, India
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Abstract
With extended periods of time following ovulation, the metaphase II stage oocyte experiences deterioration in quality referred to as post-ovulatory oocyte ageing. Post-ovulatory ageing occurs both in vivo and in vitro and has been associated with reduced fertilization rates, poor embryo quality, post-implantation errors and abnormalities in the offspring. Although the physiological consequences of post-ovulatory oocyte ageing have largely been established, the molecular mechanisms controlling this process are not well defined. This review analyses the relationships between biochemical changes exhibited by the ageing oocyte and the symptoms associated with the ageing phenotype. We also discuss molecular events that are potentially involved in orchestrating post-ovulatory ageing with a particular focus on the role of oxidative stress. We propose that oxidative stress may act as the initiator for a cascade of events that create the aged oocyte phenotype. Specifically, oxidative stress has the capacity to cause a decline in levels of critical cell cycle factors such as maturation-promoting factor, impair calcium homoeostasis, induce mitochondrial dysfunction and directly damage multiple intracellular components of the oocyte such as lipids, proteins and DNA. Finally, this review addresses current strategies for delaying post-ovulatory oocyte ageing with a particular focus on the potential use of compounds such as caffeine or selected antioxidants in the development of more refined media for the preservation of oocyte integrity during IVF procedures.
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Abstract
With extended periods of time following ovulation, the metaphase II stage oocyte experiences deterioration in quality referred to as post-ovulatory oocyte ageing. Post-ovulatory ageing occurs both in vivo and in vitro and has been associated with reduced fertilization rates, poor embryo quality, post-implantation errors and abnormalities in the offspring. Although the physiological consequences of post-ovulatory oocyte ageing have largely been established, the molecular mechanisms controlling this process are not well defined. This review analyses the relationships between biochemical changes exhibited by the ageing oocyte and the symptoms associated with the ageing phenotype. We also discuss molecular events that are potentially involved in orchestrating post-ovulatory ageing with a particular focus on the role of oxidative stress. We propose that oxidative stress may act as the initiator for a cascade of events that create the aged oocyte phenotype. Specifically, oxidative stress has the capacity to cause a decline in levels of critical cell cycle factors such as maturation-promoting factor, impair calcium homoeostasis, induce mitochondrial dysfunction and directly damage multiple intracellular components of the oocyte such as lipids, proteins and DNA. Finally, this review addresses current strategies for delaying post-ovulatory oocyte ageing with a particular focus on the potential use of compounds such as caffeine or selected antioxidants in the development of more refined media for the preservation of oocyte integrity during IVF procedures.
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Choi S, Na HY, Kim JA, Cho SE, Suh SH. Contradictory Effects of Superoxide and Hydrogen Peroxide on KCa3.1 in Human Endothelial Cells. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2013; 17:181-7. [PMID: 23776393 PMCID: PMC3682077 DOI: 10.4196/kjpp.2013.17.3.181] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 05/15/2013] [Accepted: 05/20/2013] [Indexed: 01/18/2023]
Abstract
Reactive oxygen species (ROS) are generated in various cells, including vascular smooth muscle and endothelial cells, and regulate ion channel functions. KCa3.1 plays an important role in endothelial functions. However, the effects of superoxide and hydrogen peroxide radicals on the expression of this ion channel in the endothelium remain unclear. In this study, we examined the effects of ROS donors on KCa3.1 expression and the K+ current in primary cultured human umbilical vein endothelial cells (HUVECs). The hydrogen peroxide donor, tert-butyl hydroperoxide (TBHP), upregulated KCa3.1 expression, while the superoxide donors, xanthine/xanthine oxidase mixture (X/XO) and lysopho-sphatidylcholine (LPC), downregulated its expression, in a concentration-dependent manner. These ROS donor effects were prevented by antioxidants or superoxide dismustase. Phosphorylated extracellular signal-regulated kinase (pERK) was upregulated by TBHP and downregulated by X/XO. In addition, repressor element-1-silencing transcription factor (REST) was downregulated by TBHP, and upregulated by X/XO. Furthermore, KCa3.1 current, which was activated by clamping cells with 1 µM Ca2+ and applying the KCa3.1 activator 1-ethyl-2-benzimidazolinone, was further augmented by TBHP, and inhibited by X/XO. These effects were prevented by antioxidants. The results suggest that hydrogen peroxide increases KCa3.1 expression by upregulating pERK and downregulating REST, and augments the K+ current. On the other hand, superoxide reduces KCa3.1 expression by downregulating pERK and upregulating REST, and inhibits the K+ current. ROS thereby play a key role in both physiological and pathological processes in endothelial cells by regulating KCa3.1 and endothelial function.
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Affiliation(s)
- Shinkyu Choi
- Department of Physiology and Medical Research Institute, School of Medicine, Ewha Womans University, Seoul 158-710, Korea
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17
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Xian JA, Miao YT, Li B, Guo H, Wang AL. Apoptosis of tiger shrimp (Penaeus monodon) haemocytes induced by Escherichia coli lipopolysaccharide. Comp Biochem Physiol A Mol Integr Physiol 2013; 164:301-6. [DOI: 10.1016/j.cbpa.2012.10.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 10/07/2012] [Accepted: 10/08/2012] [Indexed: 10/27/2022]
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18
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Sun L, Yau HY, Wong WY, Li RA, Huang Y, Yao X. Role of TRPM2 in H(2)O(2)-induced cell apoptosis in endothelial cells. PLoS One 2012; 7:e43186. [PMID: 22916222 PMCID: PMC3423428 DOI: 10.1371/journal.pone.0043186] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 07/18/2012] [Indexed: 01/21/2023] Open
Abstract
Melastatin-like transient receptor potential channel 2 (TRPM2) is an oxidant-sensitive and cationic non-selective channel that is expressed in mammalian vascular endothelium. Here we investigated the functional role of TRPM2 channels in hydrogen peroxide (H(2)O(2))-induced cytosolic Ca(2+) ([Ca(2+)](i)) elavation, whole-cell current increase, and apoptotic cell death in murine heart microvessel endothelial cell line H5V. A TRPM2 blocking antibody (TM2E3), which targets the E3 region near the ion permeation pore of TRPM2, was developed. Treatment of H5V cells with TM2E3 reduced the [Ca(2+)](i) rise and whole-cell current change in response to H(2)O(2). Suppressing TRPM2 expression using TRPM2-specific short hairpin RNA (shRNA) had similar inhibitory effect. H(2)O(2)-induced apoptotic cell death in H5V cells was examined using MTT assay, DNA ladder formation analysis, and DAPI-based nuclear DNA condensation assay. Based on these assays, TM2E3 and TRPM2-specific shRNA both showed protective effect against H(2)O(2)-induced apoptotic cell death. TM2E3 and TRPM2-specific shRNA also protect the cells from tumor necrosis factor (TNF)-α-induced cell death in MTT assay. In contrast, overexpression of TRPM2 in H5V cells resulted in an increased response in [Ca(2+)](i) and whole-cell currents to H(2)O(2). TRPM2 overexpression also aggravated the H(2)O(2)-induced apoptotic cell death. Downstream pathways following TRPM2 activation was examined. Results showed that TRPM2 activity stimulated caspase-8, caspase-9 and caspase-3. These findings strongly suggest that TRPM2 channel mediates cellular Ca(2+) overload in response to H(2)O(2) and contribute to oxidant-induced apoptotic cell death in vascular endothelial cells. Down-regulating endogenous TRPM2 could be a means to protect the vascular endothelial cells from apoptotic cell death.
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Affiliation(s)
- Lei Sun
- Li Ka Shing Institute of Health Sciences and School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
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19
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Jiménez-Corona AE, Damián-Zamacona S, Pérez-Torres A, Moreno A, Mas-Oliva J. Osteopontin Upregulation in Atherogenesis Is Associated with Cellular Oxidative Stress Triggered by the Activation of Scavenger Receptors. Arch Med Res 2012; 43:102-11. [DOI: 10.1016/j.arcmed.2012.03.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 02/10/2012] [Indexed: 10/28/2022]
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20
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Chiurchiù V, Maccarrone M. Chronic inflammatory disorders and their redox control: from molecular mechanisms to therapeutic opportunities. Antioxid Redox Signal 2011; 15:2605-41. [PMID: 21391902 DOI: 10.1089/ars.2010.3547] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A chronic inflammatory disease is a condition characterized by persistent inflammation. A number of human pathologies fall into this category, and a great deal of research has been conducted to learn more about their characteristics and underlying mechanisms. In many cases, a genetic component has been identified, but also external factors like food, smoke, or environmental pollutants can significantly contribute to worsen their symptoms. Accumulated evidence clearly shows that chronic inflammatory diseases are subjected to a redox control. Here, we shall review the identity, source, regulation, and biological activity of redox molecules, to put in a better perspective their key-role in cancer, diabetes, cardiovascular diseases, atherosclerosis, chronic obstructive pulmonary diseases, and inflammatory bowel diseases. In addition, the impact of redox species on autoimmune disorders (rheumatoid arthritis, systemic lupus erythematosus, psoriasis, and celiac disease) and neurodegenerative diseases (Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and multiple sclerosis) will be discussed, along with their potential therapeutic implications as novel drugs to combat chronic inflammatory disorders.
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Affiliation(s)
- Valerio Chiurchiù
- European Center for Brain Research/Santa Lucia Foundation, Rome, Italy
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21
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Sun L, Yau HY, Lau OC, Huang Y, Yao X. Effect of hydrogen peroxide and superoxide anions on cytosolic Ca2+: comparison of endothelial cells from large-sized and small-sized arteries. PLoS One 2011; 6:e25432. [PMID: 21966527 PMCID: PMC3180448 DOI: 10.1371/journal.pone.0025432] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Accepted: 09/05/2011] [Indexed: 11/18/2022] Open
Abstract
We compared the Ca2+ responses to reactive oxygen species (ROS) between mouse endothelial cells derived from large-sized arteries, aortas (aortic ECs), and small-sized arteries, mesenteric arteries (MAECs). Application of hydrogen peroxide (H2O2) caused an increase in cytosolic Ca2+ levels ([Ca2+]i) in both cell types. The [Ca2+]i rises diminished in the presence of U73122, a phospholipase C inhibitor, or Xestospongin C (XeC), an inhibitor for inositol-1,4,5-trisphosphate (IP3) receptors. Removal of Ca2+ from the bath also decreased the [Ca2+]i rises in response to H2O2. In addition, treatment of endothelial cells with H2O2 reduced the [Ca2+]i responses to subsequent challenge of ATP. The decreased [Ca2+]i responses to ATP were resulted from a pre-depletion of intracellular Ca2+ stores by H2O2. Interestingly, we also found that Ca2+ store depletion was more sensitive to H2O2 treatment in endothelial cells of mesenteric arteries than those of aortas. Hypoxanthine-xanthine oxidase (HX-XO) was also found to induce [Ca2+]i rises in both types of endothelial cells, the effect of which was mediated by superoxide anions and H2O2 but not by hydroxyl radical. H2O2 contribution in HX-XO-induced [Ca2+]i rises were more significant in endothelial cells from mesenteric arteries than those from aortas. In summary, H2O2 could induce store Ca2+ release via phospholipase C-IP3 pathway in endothelial cells. Resultant emptying of intracellular Ca2+ stores contributed to the reduced [Ca2+]i responses to subsequent ATP challenge. The [Ca2+]i responses were more sensitive to H2O2 in endothelial cells of small-sized arteries than those of large-sized arteries.
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Affiliation(s)
- Lei Sun
- School of Biomedical Sciences and Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Ho-Yan Yau
- School of Biomedical Sciences and Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - On-Chai Lau
- School of Biomedical Sciences and Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Yu Huang
- School of Biomedical Sciences and Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Xiaoqiang Yao
- School of Biomedical Sciences and Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China
- * E-mail:
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22
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Jiang Z, Hu Z, Zeng L, Lu W, Zhang H, Li T, Xiao H. The role of the Golgi apparatus in oxidative stress: is this organelle less significant than mitochondria? Free Radic Biol Med 2011; 50:907-17. [PMID: 21241794 DOI: 10.1016/j.freeradbiomed.2011.01.011] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Revised: 12/30/2010] [Accepted: 01/08/2011] [Indexed: 10/18/2022]
Abstract
Reactive oxygen species (ROS)/reactive nitrogen species (RNS) and ROS/RNS-mediated oxidative stress have well-established roles in many physiological and pathological processes and are associated with the pathogenesis of many diseases, such as hypertension, ischemia/reperfusion injury, diabetes mellitus, atherosclerosis, stroke, cancer, and neurodegenerative disorders. It is generally accepted that mitochondria play an essential role in oxidative stress because they are responsible for the primary generation of superoxide radicals. Little attention, however, has been paid to the importance of the Golgi apparatus (GA) in this process. The GA is a pivotal organelle in cell metabolism and participates in modifying, sorting, and packaging macromolecules for cell secretion or use within the cell. It is inevitably involved in the process of oxidative stress, which can cause modification and damage of lipids, proteins, DNA, and other structural constituents. Here we discuss the connections between the GA and oxidative stress and highlight the role of the GA in oxidative stress-related Ca(2+)/Mn(2+) homeostasis, cell apoptosis, sphingolipid metabolism, signal transduction, and antioxidation. We also provide a novel perspective on the subcellular significance of oxidative stress and its pathological implications and present "GA stress" as a new concept to explain the GA-specific stress response.
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Affiliation(s)
- Zheng Jiang
- Department of Neurology, Second Xiangya Hospital, Central South University, Changsha 410011, China
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23
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Li W, Shi YH, Yang RL, Cui J, Xiao Y, Le GW. Reactive oxygen species serve as signals mediating glucose-stimulated somatostatin secretion from cultured rat gastric primary D-cells. Free Radic Res 2010; 44:614-23. [PMID: 20370561 DOI: 10.3109/10715761003713549] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Somatostatin plays an important role in glucose homeostasis. It is normally secreted in response to glucose and ATP generation is believed to be the key transduction signal of glucose-stimulated somatostatin secretion (GSSS). However, in the present study, in cultured rat gastric primary D-cells, GSSS was accompanied by increases in cellular reactive oxygen species (ROS). GSSS is dependent on the cellular ROS and independently of the ATP production linked to glucose metabolism. The antioxidant, alpha-lipoic acid or catalase inhibitor, 3-aminotriazole can influence the intracellular calcium concentration and abolish or further elevate GSSS. It is suggested that ROS production may serve as a signal modulating the necessary Ca(2+) recruitment for GSSS. Since somatostatin is thought to exert broad regulatory functions on gastrointestinal physiology and nutrient intake, the interaction with ROS may lead to potential targets for mediating nutrition and energy homeostasis.
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Affiliation(s)
- Wu Li
- State Key Lab of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu Province, PR China
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24
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Khoo NKH, White CR, Pozzo-Miller L, Zhou F, Constance C, Inoue T, Patel RP, Parks DA. Dietary flavonoid quercetin stimulates vasorelaxation in aortic vessels. Free Radic Biol Med 2010; 49:339-47. [PMID: 20423726 PMCID: PMC2900862 DOI: 10.1016/j.freeradbiomed.2010.04.022] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 03/16/2010] [Accepted: 04/16/2010] [Indexed: 12/26/2022]
Abstract
Considerable epidemiological evidence indicates that dietary consumption of moderate levels of polyphenols decreases both the incidence of cardiovascular disease and the mortality associated with myocardial infarction. Molecular mechanisms of this cardiovascular protection remain uncertain but can involve changes in rates of nitric oxide (NO) generation by endothelial nitric oxide synthase (eNOS). We examined the vascular responses to quercetin using a combination of biochemical and vessel function criteria. Quercetin treatment for 30min enhanced relaxation of rat aortic ring segments. Moreover, the addition of L-NAME (100muM) or charybdotoxin (ChTx) blocked quercetin-mediated vasorelaxation thus demonstrating the effect was partially dependent on NOS and endothelium-derived hyperpolarizing factor (EDHF). Additionally, bovine aortic endothelial cells (BAEC) treated with quercetin showed a rapid increase of intracellular Ca(2+) concentrations as well as a dose- and time-dependent stimulation of eNOS phosphorylation with a concomitant increase in NO production. These results demonstrate that quercetin-mediated stimulation of eNOS phosphorylation increases NO bioavailability in endothelial cells and can thus play a role in the vascular protective effects associated with improved endothelial cell function.
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Affiliation(s)
- Nicholas K H Khoo
- Department of Anesthesiology, The University of Alabama at Birmingham, Birmingham, AL 35294-2172, USA.
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25
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Kaur G, Jaggi AS, Singh N. Exploring the potential effect of Ocimum sanctum in vincristine-induced neuropathic pain in rats. J Brachial Plex Peripher Nerve Inj 2010; 5:3. [PMID: 20181005 PMCID: PMC2832770 DOI: 10.1186/1749-7221-5-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Accepted: 01/25/2010] [Indexed: 12/29/2022] Open
Abstract
The present study was designed to investigate the ameliorative potential of Ocimum sanctum and its saponin rich fraction in vincristine-induced peripheral neuropathic pain in rats. Peripheral neuropathy was induced in rats by administration of vincristine sulfate (50 mug/kg i.p.) for 10 consecutive days. The mechanical hyperalgesia, cold allodynia, paw heat hyperalgesia and cold tail hyperalgesia were assessed by performing the pinprick, acetone, hot plate and cold tail immersion tests, respectively. Biochemically, the tissue thio-barbituric acid reactive species (TBARS), super-oxide anion content (markers of oxidative stress) and total calcium levels were measured. Vincristine administration was associated with the development of mechanical hyperalgesia, cold allodynia, heat and cold hyperalgesia. Furthermore, vincristine administration was also associated with an increase in oxidative stress and calcium levels. However, administration of Ocimum sanctum (100 and 200 mg/kg p.o.) and its saponin rich fraction (100 and 200 mg/kg p.o.) for 14 days significantly attenuated vincristine-induced neuropathic pain along with decrease in oxidative stress and calcium levels. It may be concluded that Ocimum sanctum has ameliorative potential in attenuating chemotherapy induced-painful neuropathic state, which may be attributed to decrease in oxidative stress and calcium levels. Furthermore, saponin rich fraction of Ocimum sanctum may be responsible for its noted beneficial effect in neuropathic pain in rats.
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Affiliation(s)
- Gurpreet Kaur
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, India
| | - Amteshwar Singh Jaggi
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, India
| | - Nirmal Singh
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, India
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26
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Dejeans N, Tajeddine N, Beck R, Verrax J, Taper H, Gailly P, Calderon PB. Endoplasmic reticulum calcium release potentiates the ER stress and cell death caused by an oxidative stress in MCF-7 cells. Biochem Pharmacol 2009; 79:1221-30. [PMID: 20006589 DOI: 10.1016/j.bcp.2009.12.009] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Revised: 12/04/2009] [Accepted: 12/07/2009] [Indexed: 02/01/2023]
Abstract
Increase in cytosolic calcium concentration ([Ca2+](c)), release of endoplasmic reticulum (ER) calcium ([Ca2+](er)) and ER stress have been proposed to be involved in oxidative toxicity. Nevertheless, their relative involvements in the processes leading to cell death are not well defined. In this study, we investigated whether oxidative stress generated during ascorbate-driven menadione redox cycling (Asc/Men) could trigger these three events, and, if so, whether they contributed to Asc/Men cytoxicity in MCF-7 cells. Using microspectrofluorimetry, we demonstrated that Asc/Men-generated oxidative stress was associated with a slow and moderate increase in [Ca2+](c), largely preceding permeation of propidium iodide, and thus cell death. Asc/Men treatment was shown to partially deplete ER calcium stores after 90 min (decrease by 45% compared to control). This event was associated with ER stress activation, as shown by analysis of eIF2 phosphorylation and expression of the molecular chaperone GRP94. Thapsigargin (TG) was then used to study the effect of complete [Ca2+](er) emptying during the oxidative stress generated by Asc/Men. Surprisingly, the combination of TG and Asc/Men increased ER stress to a level considerably higher than that observed for either treatment alone, suggesting that [Ca2+](er) release alone is not sufficient to explain ER stress activation during oxidative stress. Finally, TG-mediated [Ca2+](er) release largely potentiated ER stress, DNA fragmentation and cell death caused by Asc/Men, supporting a role of ER stress in the process of Asc/Men cytotoxicity. Taken together, our results highlight the involvement of ER stress and [Ca2+](er) decrease in the process of oxidative stress-induced cell death in MCF-7 cells.
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Affiliation(s)
- Nicolas Dejeans
- Université Catholique de Louvain, Louvain Drug Research Institute, Toxicology and Cancer Biology Research Group, PMNT Unit, Belgium
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27
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Juffermans LJM, van Dijk A, Jongenelen CAM, Drukarch B, Reijerkerk A, de Vries HE, Kamp O, Musters RJP. Ultrasound and microbubble-induced intra- and intercellular bioeffects in primary endothelial cells. ULTRASOUND IN MEDICINE & BIOLOGY 2009; 35:1917-27. [PMID: 19766381 DOI: 10.1016/j.ultrasmedbio.2009.06.1091] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Revised: 05/27/2009] [Accepted: 06/08/2009] [Indexed: 05/05/2023]
Abstract
Recent developments in the field of ultrasound (US) contrast agents have demonstrated that these encapsulated microbubbles can not only be used for diagnostic imaging but may also be employed as therapeutic carriers for localized, targeted drug or gene delivery. The exact mechanisms behind increased uptake of therapeutic compounds by US-exposed microbubbles are still not fully understood. Therefore, we studied the effects of stably oscillating SonoVue microbubbles on relevant parameters of cellular and intercellular permeability, i.e., reactive oxygen species (ROS) homeostasis, calcium permeability, F-actin cytoskeleton, monolayer integrity and cell viability using live-cell fluorescence microscopy. US was applied at 1-MHz, 0.1MPa peak-negative pressure, 0.2% duty cycle and 20Hz pulse repetition frequency to primary endothelial cells. We demonstrated increased membrane permeability for calcium ions, with an important role for H(2)O(2). Catalase, an extracellular H(2)O(2) scavenger, significantly blocked the influx of calcium ions. Further changes in ROS homeostasis involved an increase in intracellular H(2)O(2) levels, protein nitrosylation and a decrease in total endogenous glutathione levels. In addition, an increase in the number of F-actin stress fibers and F-actin cytoskeletal rearrangement were observed. Furthermore, US-exposed microbubbles significantly affected endothelial monolayer integrity, but importantly, disrupted cell-cell interactions were restored within 30min. Finally, cell viability was not affected. In conclusion, these data provide more insight in the interactions between US, microbubbles and endothelial cells, which is important for understanding the mechanisms behind US and microbubble-enhanced uptake of drugs or genes.
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Affiliation(s)
- Lynda J M Juffermans
- Department of Physiology, VU University Medical Center, 1081 BT Amsterdam, The Netherlands.
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28
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Krasowska M, Grzywna ZJ, Mycielska ME, Djamgoz MBA. Fractal analysis and ionic dependence of endocytotic membrane activity of human breast cancer cells. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2009; 38:1115-25. [PMID: 19618177 DOI: 10.1007/s00249-009-0516-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Revised: 06/24/2009] [Accepted: 06/29/2009] [Indexed: 10/20/2022]
Abstract
The endocytic membrane activities of two human breast cancer cell lines (MDA-MB-231 and MCF-7) of strong and weak metastatic potential, respectively, were studied in a comparative approach. Uptake of horseradish peroxidase was used to follow endocytosis. Dependence on ionic conditions and voltage-gated sodium channel (VGSC) activity were characterized. Fractal methods were used to analyze quantitative differences in vesicular patterning. Digital quantification showed that MDA-MB-231 cells took up more tracer (i.e., were more endocytic) than MCF-7 cells. For the former, uptake was totally dependent on extracellular Na(+) and partially dependent on extracellular and intracellular Ca(2+) and protein kinase activity. Analyzing the generalized fractal dimension (D(q )) and its Legendre transform f(alpha) revealed that under control conditions, all multifractal parameters determined had values greater for MDA-MB-231 compared with MCF-7 cells, consistent with endocytic/vesicular activity being more developed in the strongly metastatic cells. All fractal parameters studied were sensitive to the VGSC blocker tetrodotoxin (TTX). Some of the parameters had a "simple" dependence on VGSC activity, if present, whereby pretreatment with TTX reduced the values for the MDA-MB-231 cells and eliminated the differences between the two cell lines. For other parameters, however, there was a "complex" dependence on VGSC activity. The possible physical/physiological meaning of the mathematical parameters studied and the nature of involvement of VGSC activity in control of endocytosis/secretion are discussed.
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Affiliation(s)
- Monika Krasowska
- Division of Cell and Molecular Biology, Neuroscience Solutions to Cancer Research Group, Imperial College London, Sir Alexander Fleming Building, South Kensington Campus, London SW7 2AZ, UK.
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29
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Zhou X, Wen K, Yuan D, Ai L, He P. Calcium influx-dependent differential actions of superoxide and hydrogen peroxide on microvessel permeability. Am J Physiol Heart Circ Physiol 2009; 296:H1096-107. [PMID: 19201997 DOI: 10.1152/ajpheart.01037.2008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Our previous study demonstrated that reactive oxygen species (ROS) released from activated blood cells contribute significantly to the increased microvessel permeability during inflammation. This study aims to define the individual roles of hydrogen peroxide (H(2)O(2)) and superoxide in ROS-induced increases in permeability and endothelial intracellular Ca(2+) concentration ([Ca(2+)](i)) in individually perfused rat mesenteric venules. Microvessel permeability was determined by measuring hydraulic conductivity (L(p)). Endothelial [Ca(2+)](i) was measured in fura-2 AM-loaded microvessels. Perfusing microvessels with superoxide generated by hypoxanthine and xanthine oxidase (HX/XO) induced immediate and transient increases in L(p). The mean peak value, which occurred within 5 min of HX/XO exposure, was 4.3 +/- 0.6 times that of the control. In contrast, the perfusion of H(2)O(2) (100 and 500 microM) caused no immediate increases in L(p). A significant L(p) increase, 3.6 +/- 0.6 times the control value, occurred 30 min after the perfusion of H(2)O(2) at 500 microM. The perfusion of H(2)O(2) at 100 or 500 microM for 1 h increased L(p) to 6.6 +/- 0.9 and 11.3 +/- 3.6 times the control value, respectively. The increased endothelial [Ca(2+)](i) in HX/XO or H(2)O(2) perfused vessels was correlated with the time course of the increases in L(p). Inhibiting Ca(2+) influx by LaCl(3) prevented the permeability increase induced by HX/XO or H(2)O(2). These results demonstrated differential actions of superoxide and H(2)O(2) on microvessel permeability and endothelial [Ca(2+)](i). Superoxide-induced permeability increases were immediate and transient, whereas H(2)O(2)-induced permeability increases were progressive, demonstrating concentration and time dependence. Ca(2+) influx plays an essential role in both superoxide and H(2)O(2)-induced permeability increases.
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Affiliation(s)
- Xueping Zhou
- Dept. of Physiology and Pharmacology, School of Medicine, West Virginia Univ., Morgantown, WV 26506-9229, USA
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30
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Ricono JM, Wagner B, Gorin Y, Arar M, Kazlauskas A, Choudhury GG, Abboud HE. PDGF receptor-{beta} modulates metanephric mesenchyme chemotaxis induced by PDGF AA. Am J Physiol Renal Physiol 2008; 296:F406-17. [PMID: 19019919 DOI: 10.1152/ajprenal.90368.2008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
PDGF B chain or PDGF receptor (PDGFR)-beta-deficient (-/-) mice lack mesangial cells. To study responses of alpha- and beta-receptor activation to PDGF ligands, metanephric mesenchymal cells (MMCs) were established from embryonic day E11.5 wild-type (+/+) and -/- mouse embryos. PDGF BB stimulated cell migration in +/+ cells, whereas PDGF AA did not. Conversely, PDGF AA was chemotactic for -/- MMCs. The mechanism by which PDGFR-beta inhibited AA-induced migration was investigated. PDGF BB, but not PDGF AA, increased intracellular Ca(2+) and the production of reactive oxygen species (ROS) in +/+ cells. Transfection of -/- MMCs with the wild-type beta-receptor restored cell migration and ROS generation in response to PDGF BB and inhibited AA-induced migration. Inhibition of Ca(2+) signaling facilitated PDGF AA-induced chemotaxis in the wild-type cells. The antioxidant N-acetyl-l-cysteine (NAC) or the NADPH oxidase inhibitor diphenyleneiodonium (DPI) abolished the BB-induced increase in intracellular Ca(2+) concentration, suggesting that ROS act as upstream mediators of Ca(2+) in suppressing PDGF AA-induced migration. These data indicate that ROS and Ca(2+) generated by active PDGFR-beta play an essential role in suppressing PDGF AA-induced migration in +/+ MMCs. During kidney development, PDGFR beta-mediated ROS generation and Ca(2+) influx suppress PDGF AA-induced chemotaxis in metanephric mesenchyme.
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Affiliation(s)
- Jill M Ricono
- Department of Molecular Medicine, Institute of Biotechnology, Univ. of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900, USA
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Muthuraman A, Diwan V, Jaggi AS, Singh N, Singh D. Ameliorative effects of Ocimum sanctum in sciatic nerve transection-induced neuropathy in rats. JOURNAL OF ETHNOPHARMACOLOGY 2008; 120:56-62. [PMID: 18762236 DOI: 10.1016/j.jep.2008.07.049] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 07/04/2008] [Accepted: 07/28/2008] [Indexed: 05/26/2023]
Abstract
OBJECTIVES The present study was aimed at investigating the ameliorative effect of Ocimum sanctum in sciatic nerve transection (axotomy)-induced peripheral neuropathy in rats. MATERIALS AND METHODS Sciatic nerve transection-induced axonal degeneration was assessed histopathologically. Paw pressure, Von Frey Hair, tail cold-hyperalgesia, motor in-coordination tests were performed to assess the extent of neuropathy. Biochemical estimations of thiobarbituric acid reactive species (TBARS), reduced glutathione (GSH), and total calcium levels were also performed. Methanolic extract of Ocimum sanctum at different doses (50, 100 and 200mg/kg p.o.) was administered for 10 consecutive days starting from the day of surgery. RESULTS Administration of Ocimum sanctum attenuated sciatic nerve transection-induced axonal degeneration, reduction of nociceptive threshold and motor in-coordination. Moreover, it also attenuated axotomy-induced rise in TBARS, total calcium and decrease in GSH levels in a dose-dependent manner. CONCLUSION Anti-oxidant and calcium attenuating actions may be responsible for observed ameliorative effects of Ocimum sanctum in axotomy-induced neuropathy.
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Affiliation(s)
- A Muthuraman
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala 147002, India
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Comparative study of hydrogen peroxide- and 4-hydroxy-2-nonenal-induced cell death in HT22 cells. Neurochem Int 2008; 52:776-85. [DOI: 10.1016/j.neuint.2007.09.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2007] [Revised: 08/22/2007] [Accepted: 09/13/2007] [Indexed: 11/18/2022]
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Florea SM, Blatter LA. The effect of oxidative stress on Ca2+ release and capacitative Ca2+ entry in vascular endothelial cells. Cell Calcium 2007; 43:405-15. [PMID: 17767954 DOI: 10.1016/j.ceca.2007.07.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Revised: 06/19/2007] [Accepted: 07/15/2007] [Indexed: 01/24/2023]
Abstract
Oxidative stress imposed by the accumulation of oxygen free radicals (reactive oxygen species, ROS) has profound effects on Ca2+ homeostasis in the vascular endothelium, leading to endothelial dysfunctions and the development of cardiovascular pathologies. We tested the effect of the oxidant and ROS generator tert-butyl-hydroperoxide (tBuOOH) on Ca2+ signaling in single cultured calf pulmonary artery endothelial (CPAE) cells loaded with the fluorescent Ca2+ indicator indo-1. Acute brief (5 min) exposures to tBuOOH had no effect on basal cytosolic free Ca2+ ([Ca2+](i)), agonist (ATP)-induced Ca2+ release from the endoplasmic reticulum (ER) and on Ca(2+) store depletion-dependent capacitative Ca2+ entry (CCE). Prolonged (60 min) exposure to tBuOOH did not affect intracellular Ca2+ release, but caused a profound inhibition of CCE. After 120 min of treatment with tBuOOH not only was CCE further reduced, but also ATP-induced Ca2+ release due to a slow depletion of the stores that resulted from CCE inhibition. The antioxidant Trolox (synthetic vitamin E analog) prevented the inhibition of CCE by tBuOOH and attenuated the increase of [ROS](i), indicating that inhibition of CCE was due to the oxidant effects of tBuOOH. The data suggest that in vascular endothelial cells oxidative stress primarily affects Ca2+ influx in response to Ca2+ loss from internal stores. [Ca2+](i) is an important signal for the production and release of endothelium-derived factors such as nitric oxide (NO). Since CCE is the preferential Ca2+ source for NO synthase activation, the finding that oxidative stress inhibits CCE may explain how oxidative stress contributes to endothelial dysfunction-related cardiovascular pathologies.
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Affiliation(s)
- Stela M Florea
- Department of Physiology, Loyola University Chicago, 2160 S. First Avenue, Maywood, IL 60153, USA
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Elahi MM, Naseem KM, Matata BM. Nitric oxide in blood. The nitrosative-oxidative disequilibrium hypothesis on the pathogenesis of cardiovascular disease. FEBS J 2007; 274:906-23. [PMID: 17244198 DOI: 10.1111/j.1742-4658.2007.05660.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
There is growing evidence that altered production and/or spatio-temporal distribution of reactive oxidant species and reactive nitrosative species in blood creates oxidative and/or nitrosative stresses in the failing myocardium and endothelium. This contributes to the abnormal cardiac and vascular phenotypes that characterize cardiovascular disease. These derangements at the system level can now be interpreted at the integrated cellular and molecular levels in terms of effects on signaling elements in the heart and vasculature. The end results of nitric oxide/redox disequilibrium have implications for cardiac and vascular homeostasis and may result in the development of atherosclerosis, myocardial tissue remodelling and hypertrophy. Reactive oxygen species/reactive nitrogen species generation is also attributed to the transit from hypertrophic to apoptotic phenotypes, a possible mechanism of myocardial failure. In this review, we highlight the possible roles of altered production and/or spatio-temporal distribution of reactive oxidant species and reactive nitrosative species in blood on the pathogenesis of the failing cardiovascular system.
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Martínez-Burgos MA, Granados MP, González A, Rosado JA, Yago MD, Salido GM, Martínez-Victoria E, Mañas M, Pariente JA. Involvement of ryanodine-operated channels in tert-butylhydroperoxide-evoked Ca2+ mobilisation in pancreatic acinar cells. ACTA ACUST UNITED AC 2006; 209:2156-64. [PMID: 16709917 DOI: 10.1242/jeb.02250] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Reactive oxygen species and related oxidative damage have been implicated in the initiation of acute pancreatitis, a disease characterised in its earliest stages by disruption of intracellular Ca2+ homeostasis. The present study was carried out in order to establish the effect of the organic pro-oxidant, tert-butylhydroperoxide (tBHP), on the mobilisation of intracellular Ca2+ stores in isolated rat pancreatic acinar cells and the mechanisms underlying this effect. Cytosolic free Ca2+ concentrations ([Ca2+]c) were monitored using a digital microspectrofluorimetric system in fura-2 loaded cells. In the presence of normal extracellular Ca2+ concentrations ([Ca2+]o), perfusion of pancreatic acinar cells with 1 mmol l-1 tBHP caused a slow sustained increase in [Ca2+]c. This increase was also observed in a nominally Ca2+-free medium, indicating a release of Ca2+ from intracellular stores. Pretreatment of cells with tBHP abolished the typical Ca2+ response of both the physiological agonist CCK-8 (1 nmol l-1) and thapsigargin (TPS, 1 micromol l-1), an inhibitor of the SERCA pump, in the absence of extracellular Ca2+. Similar results were observed with carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP, 0.5 micromol l-1), a mitochondrial uncoupler. In addition, depletion of either agonist-sensitive Ca2+ pools by CCK-8 or TPS or mitochondrial Ca2+ pools by FCCP were unable to prevent the tBHP-induced Ca2+ release. By contrast, simultaneous administration of TPS and FCCP clearly abolished the tBHP-induced Ca2+ release. These results show that tBHP releases Ca2+ from agonist-sensitive intracellular stores and from mitochondria. On the other hand, simultaneous application of FCCP and of 2-aminoethoxydiphenylborane (2-APB), a blocker of IP3-mediated Ca2+ release, was unable to suppress the increase in [Ca2+]c induced by tBHP, while the application of 50 micromol l-1 of ryanodine (which is able to block the ryanodine channels) inhibits tBHP-evoked Ca2+ mobilisation. These findings indicate that tBHP releases Ca2+ from non-mitochondrial Ca2+ pools through ryanodine channels.
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Affiliation(s)
- María A Martínez-Burgos
- Institute of Nutrition and Food Technology, Department of Physiology, University of Granada, C/Ramón y Cajal, 4. 18071, Granada, Spain.
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36
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Yan Y, Wei CL, Zhang WR, Cheng HP, Liu J. Cross-talk between calcium and reactive oxygen species signaling. Acta Pharmacol Sin 2006; 27:821-6. [PMID: 16787564 DOI: 10.1111/j.1745-7254.2006.00390.x] [Citation(s) in RCA: 178] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Calcium [Ca2+] and reactive oxygen species (ROS) constitute the most important intracellular signaling molecules participating in the regulation and integration of diverse cellular functions. Here we briefly review cross-talk between the two prominent signaling systems that finely tune the homeostasis and integrate functionality of Ca2+ and ROS in different types of cells. Ca2+ modulates ROS homeostasis by regulating ROS generation and annihilation mechanisms in both the mitochondria and the cytosol. Reciprocal redox regulation of Ca2+ homeostasis occurs in different physiological and pathological processes, by modulating components of the Ca2+ signaling toolkit and altering characteristics of local and global Ca2+ signals. Functionally, interactions between Ca2+ and ROS signaling systems can be both stimulatory and inhibitory, depending on the type of target proteins, the ROS species, the dose, duration of exposure, and the cell contexts. Such extensive and complex cross-talk might enhance signaling coordination and integration, whereas abnormalities in either system might propagate into the other system and undermine the stability of both systems.
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Affiliation(s)
- Yuan Yan
- Laboratory of Calcium Signaling, Institute of Molecular Medicine, Peking University, Beijing 100871, China
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37
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Rojas A, Figueroa H, Re L, Morales MA. Oxidative stress at the vascular wall. Mechanistic and pharmacological aspects. Arch Med Res 2006; 37:436-48. [PMID: 16624640 DOI: 10.1016/j.arcmed.2005.11.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2005] [Accepted: 11/14/2005] [Indexed: 02/07/2023]
Abstract
During the process of energy production in aerobic respiration, vascular cells produce reactive oxygen species (ROS). A growing body of evidence indicates that oxidative stress refers to a condition in which cells are subjected to excessive levels of ROS. Overall vascular function is dependent upon a fine balance of oxidant and antioxidant mechanisms, which determine endothelial functions. Considerable experimental and clinical data indicate that intracellular oxidant milieu is also involved in several redox-sensitive cellular signaling pathways such as ion transport systems, protein phosphorylation, and gene expression and thus also plays important roles as modulator of vascular cell functions such as cell growth, apoptosis, migration, angiogenesis and cell adhesion. Overproduction of ROS under pathophysiologic conditions is integral in the development of cardiovascular diseases. This fact has raised an intensive search of new pharmacological approaches to improve vascular hemostasis and particularly those intended to decrease oxidative stress or augment the antioxidant defense mechanisms.
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Affiliation(s)
- Armando Rojas
- Escuela de Medicina, Facultad de Ciencias de la Salud, Universidad Católica del Maule, Talca, Chile.
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38
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Simm A, Brömme HJ. Reactive oxygen species (ROS) and aging: Do we need them — can we measure them — should we block them? ACTA ACUST UNITED AC 2005. [DOI: 10.1002/sita.200400053] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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39
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Mandal A, Chakraborti T, Choudhury R, Ghosh B, Ghosh AN, Das S, Chakraborti S. Role of MMP-2 in inhibiting Na+ dependent Ca2+ uptake by H2O2 in microsomes isolated from pulmonary smooth muscle. Mol Cell Biochem 2005; 270:79-87. [PMID: 15792356 DOI: 10.1007/s11010-005-5260-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Treatment of microsomes (preferentially enriched with endoplasmic reticulum) isolated from bovine pulmonary artery smooth muscle tissue with H2O2 (1 mM) markedly stimulated matrix metalloproteinase activity and also inhibited Na+ dependent Ca2+ uptake. Electron micrograph revealed that H2O2 (1 mM) does not cause any damage to the microsomes. MMP-2 and TIMP-2 were determined to be the ambient protease and corresponding antiprotease of the microsomes. Pretreatment with vitamin E (1 mM) and TIMP-2 (50 microg/ml) reversed the effect produced by H2O2 (1 mM) on Na+ dependent Ca2+ uptake in the microsomes. However, H2O2 (1 mM) caused changes in MMP-2 activity and Na+ dependent Ca2+ uptake were not reversed upon pretreatment of the microsomes with a low concentration of 5 microg/ml of TIMP-2 which otherwise reversed MMP-2 (1 microg/ml) mediated increase in 14C-gelatin degradation and inhibition of Na+ dependent Ca2+ uptake. Combined treatment of the microsomes with a low dose of MMP-2 (0.5 microg/ml) and H2O2 (0.5 mM) inhibited Na+ dependent Ca2+ uptake in the microsomes compared to the respective low dose of either of them. Direct treatment of TIMP-2 (5 microg/ml) with H2O2 (1 mM) abolished the inhibitory effect of the inhibitor on 14C-gelatinolytic activity elicited by 1 microg/ml of MMP-2. Thus, one of the mechanisms by which H2O2 activates MMP-2 could be due to inactivation of TIMP-2 by the oxidant. The resulting activation of MMP-2 subsequently inhibits Na+ dependent Ca2+ uptake in the microsomes.
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Affiliation(s)
- Amritlal Mandal
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, West Bengal, India
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40
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Munns SE, Lui JKC, Arthur PG. Mitochondrial hydrogen peroxide production alters oxygen consumption in an oxygen-concentration-dependent manner. Free Radic Biol Med 2005; 38:1594-603. [PMID: 15917188 DOI: 10.1016/j.freeradbiomed.2005.02.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2004] [Revised: 02/02/2005] [Accepted: 02/22/2005] [Indexed: 10/25/2022]
Abstract
Metabolic responses of mammalian cells toward declining oxygen concentration are generally thought to occur when oxygen limits mitochondrial ATP production. However, at oxygen concentrations markedly above those limiting to mitochondria, several mammalian cell types display reduced rates of oxygen consumption without energy stress or compensatory increases in glycolytic ATP production. We used mammalian Jurkat T cells as a model system to identify mechanisms responsible for these changes in metabolic rate. Oxygen consumption was 31% greater at high oxygen (150-200 microM) compared to low oxygen (5-10 microM). Hydrogen peroxide was implicated in the response as catalase prevented the increase in oxygen consumption normally associated with high oxygen. Cell-derived hydrogen peroxide, predominately from the mitochondria, was elevated with high oxygen. Oxygen consumption related to intracellular calcium turnover was shown, through EDTA chelation and dantrolene antagonism of the ryanodine receptor, to account for 70% of the response. Oligomycin inhibition of oxygen consumption indicated that mitochondrial proton leak was also sensitive to changes in oxygen concentration. Our results point toward a mechanism in which changes in oxygen concentration influence the rate of hydrogen peroxide production by mitochondria, which, in turn, alters cellular ATP use associated with intracellular calcium turnover and energy wastage through mitochondrial proton leak.
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Affiliation(s)
- Shane E Munns
- School of Biomedical & Chemical Sciences, M310, University of Western Australia, Crawley, WA 6009, Australia
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41
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Haskew-Layton RE, Mongin AA, Kimelberg HK. Hydrogen peroxide potentiates volume-sensitive excitatory amino acid release via a mechanism involving Ca2+/calmodulin-dependent protein kinase II. J Biol Chem 2004; 280:3548-54. [PMID: 15569671 DOI: 10.1074/jbc.m409803200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Excessive excitatory amino acid (EAA) release in cerebral ischemia is a major mechanism responsible for neuronal damage and death. A substantial fraction of ischemic EAA release occurs via volume-regulated anion channels (VRACs). Hydrogen peroxide (H2O2), which is abundantly produced during ischemia and reperfusion, activates a number of protein kinases critical for VRAC functioning and has recently been reported to activate VRACs. In the present study, we explored the effects of H2O2 on volume-dependent EAA release in cultured astrocytes, measured as the release of preloaded D-[3H]aspartate. 100-1,000 microm H2O2 enhanced swelling-induced EAA release by approximately 2.5-3-fold (EC50 approximately 10 microM). The VRAC blockers ATP, phloretin, and 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB) potently inhibited both control swelling-induced and the H2O2-potentiated release, suggesting a role for VRACs. The H2O2-induced component of EAA release was attenuated by the Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester (BAPTA-AM) and completely eliminated by the calmodulin antagonists trifluoperazine and W-7 and the Ca2+/calmodulin-dependent protein kinase II (CaMKII) inhibitor KN-93. Inhibitors of tyrosine kinases, protein kinase C, and the myosin light chain kinase were ineffective in blocking the H2O2 response. H2O2 treatment of swollen astrocytes, but not swelling alone, resulted in CaMKII activation that was inhibited by KN-93, as determined by a phospho-Thr286 CaMKII antibody. These data demonstrate that H2O2 strongly up-regulates astrocytic volume-sensitive EAA release via a CaMKII-dependent mechanism and in this way may potently promote pathological EAA release and brain damage in ischemia.
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Affiliation(s)
- Renée E Haskew-Layton
- Center for Neuropharmacology and Neuroscience, Albany Medical College, Albany, New York 12208, USA
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42
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Castro J, Bittner CX, Humeres A, Montecinos VP, Vera JC, Barros LF. A cytosolic source of calcium unveiled by hydrogen peroxide with relevance for epithelial cell death. Cell Death Differ 2004; 11:468-78. [PMID: 14726961 DOI: 10.1038/sj.cdd.4401372] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Oxidative stress releases intracellular calcium, which plays a pathogenic role in mammalian cell death. Here we report a search for the source of oxidative calcium in HeLa cells based on confocal epifluorescence microscopy. H(2)O(2) caused a rapid increase in cytosolic calcium, which was followed by mitochondrial Ca(2+) loading. Combined mitochondrial uncoupling with full depletion of thapsigargin-sensitive stores abrogated inositol 1,4,5-trisphosphate-mediated calcium release but failed to inhibit H(2)O(2)-induced calcium release, observation that was confirmed in MDCK cells. Prevention of peroxide-induced acidification with a pH clamp was also ineffective, discarding a role for endosomal/lysosomal Ca(2+)/H(+) exchange. Lysosomal integrity was not affected by H(2)O(2). Mature human erythrocytes also reacted to peroxide by releasing intracellular calcium, thus directly demonstrating the cytosolic source. Glutathione depletion markedly sensitized cells to H(2)O(2), an effect opposite to that achieved by DTT. Iron chelation was ineffective. In summary, our results show the existence of a previously unrecognized sulfhydryl-sensitive source of pathogenic calcium in the cytosol of mammalian cells.
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Affiliation(s)
- J Castro
- Centro de Estudios Científicos (CECS), Av. Arturo Prat 514, Casilla 1469, Valdivia, Chile
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43
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Cook-Mills JM, Johnson JD, Deem TL, Ochi A, Wang L, Zheng Y. Calcium mobilization and Rac1 activation are required for VCAM-1 (vascular cell adhesion molecule-1) stimulation of NADPH oxidase activity. Biochem J 2004; 378:539-47. [PMID: 14594451 PMCID: PMC1223954 DOI: 10.1042/bj20030794] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2003] [Revised: 10/23/2003] [Accepted: 10/31/2003] [Indexed: 01/12/2023]
Abstract
VCAM-1 (vascular cell adhesion molecule-1) plays an important role in the regulation of inflammation in atherosclerosis, asthma, inflammatory bowel disease and transplantation. VCAM-1 activates endothelial cell NADPH oxidase, and this oxidase activity is required for VCAM-1-dependent lymphocyte migration. We reported previously that a mouse microvascular endothelial cell line promotes lymphocyte migration that is dependent on VCAM-1, but not on other known adhesion molecules. Here we have investigated the signalling mechanisms underlying VCAM-1 function. Lymphocyte binding to VCAM-1 on the endothelial cell surface activated an endothelial cell calcium flux that could be inhibited with anti-alpha4-integrin and mimicked by anti-VCAM-1-coated beads. VCAM-1 stimulation of calcium responses could be blocked by an inhibitor of intracellular calcium mobilization, a calcium channel inhibitor or a calcium chelator, resulting in the inhibition of NADPH oxidase activity. Addition of ionomycin overcame the calcium channel blocker suppression of VCAM-1-stimulated NADPH oxidase activity, but could not reverse the inhibitory effect imposed by intracellular calcium blockage, indicating that both intracellular and extracellular calcium mobilization are required for VCAM-1-mediated activation of NADPH oxidase. Furthermore, VCAM-1 specifically activated the Rho-family GTPase Rac1, and VCAM-1 activation of NADPH oxidase was blocked by a dominant negative Rac1. Thus VCAM-1 stimulates the mobilization of intracellular and extracellular calcium and Rac1 activity that are required for the activation of NADPH oxidase.
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Affiliation(s)
- Joan M Cook-Mills
- Department of Pathology, University of Cincinnati, Cincinnati, OH 45267-0529, USA.
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44
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Meng Z, Nie A. Effects of hydrogen peroxide on sodium current in acutely isolated rat hippocampal CA1 neurons. Toxicol Lett 2004; 147:45-52. [PMID: 14700527 DOI: 10.1016/j.toxlet.2003.10.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The effects of hydrogen peroxide (H2O2) on sodium currents (Na+ currents) in freshly dissociated rat hippocampal neurons were studied using the whole-cell patch-clamp techniques. H2O2 caused a reversible increase of the voltage-activated Na+ currents in a concentration- and voltage-dependent manner. The half-increasing concentration (EC50) of H2O2 on Na+ currents was 10.79 microM. In addition, 10 microM H2O2 shifted the steady-state inactivation curve of Na+ currents toward positive potential (control Vh = -64.58 +/- 1.22 mV, H2O2 Vh = -53.55 +/- 0.94 mV, n = 10, P < 0.01 without changing the slope factor). However, the steady-state activation curve was not affected. These results indicated that H2O2 could increase the amplitudes of Na+ currents and change the inactivation properties of Na+ channels even in very low concentration.
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Affiliation(s)
- Ziqiang Meng
- Institute of Environmental Medicine and Toxicology, Shanxi University, Wucheng Road 36, Taiyuan 030006, PR China.
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Takahashi T, Takahashi E, Igarashi H, Tezuka N, Kurachi H. Impact of oxidative stress in aged mouse oocytes on calcium oscillations at fertilization. Mol Reprod Dev 2003; 66:143-52. [PMID: 12950101 DOI: 10.1002/mrd.10341] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In vivo post-ovulatory aging of oocytes significantly affects the development of oocytes and embryos. Also, oocyte aging alters the regulation of the intracellular calcium concentration, thus affecting Ca(2+) oscillations in fertilized oocytes. Because reactive oxygen species (ROS) are known to significantly perturb Ca(2+) homeostasis mainly through direct effects on the machinery involved in intracellular Ca(2+) storage, we hypothesized that the poor development of aged oocytes that may have been exposed to oxidative stress for a prolonged time might arise from impaired Ca(2+)-oscillation-dependent signaling. The fertilization rates of aged oocytes and of fresh oocytes treated with 100 microM hydrogen peroxide (H(2)O(2)) for 10 min were significantly lower than that of fresh oocytes. Comparing within the fertilized oocytes, blastocyst formation was decreased while embryo fragmentation was increased similarly in the aged and H(2)O(2)-treated fresh oocytes. The frequency of Ca(2+) oscillations was significantly increased whereas the amplitude of individual Ca(2+) transients was lowered in the aged and H(2)O(2)-treated fresh oocytes. The rates of rise and decline in individual Ca(2+) transients were decreased in these oocytes, indicating impaired Ca(2+) handling. When lipid peroxidation was assessed using 4,4-difluoro-5-(4-phenyl-1,3-buttadienyl)-4-bora-3a, 4a-diaza-s-indacene-3-undecanoic acid (C11-BODIPY) in unfertilized oocytes placed in a 5% CO(2) in air atmosphere, the green fluorescence (indicating lipid peroxidation) increased faster in the aged oocytes than in the fresh oocytes. Furthermore, the green fluorescence in the aged oocytes was already approximately 20 times higher than that in the fresh oocytes at the beginning of the measurements. These findings support the idea that Ca(2+) oscillations play a key role in the development of fertilized aged oocytes.
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Affiliation(s)
- Toshifumi Takahashi
- Department of Obstetrics and Gynecology, Yamagata University School of Medicine, Yamagata, Japan
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Yang H, Shi M, Richardson A, Vijg J, Guo Z. Attenuation of leukocyte-endothelium interaction by antioxidant enzymes. Free Radic Biol Med 2003; 35:266-76. [PMID: 12885588 DOI: 10.1016/s0891-5849(03)00277-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This report assessed the effect of overexpressing Cu,Zn superoxide dismutase (SOD) and/or catalase on the interaction of mononuclear cells (MNCs) and endothelial cells (ECs). ECs were obtained from the aorta of wild-type mice and transgenic mice overexpressing Cu,ZnSOD and/or catalase. MNCs were obtained from wild-type mice. Treatment of wild-type ECs with CuSO4-oxidized low-density lipoprotein (oxLDL) significantly elevated the expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) and increased the adherence of MNCs. Overexpression of Cu,ZnSOD and/or catalase in ECs attenuated the adherence of MNCs and the expression of cell adhesion molecules induced by oxLDL. For example, ECs overexpressing Cu,ZnSOD and/or catalase showed significantly less expression of VCAM-1 and ICAM-1 and less number of adherent MNCs than wild-type ECs. Moreover, ECs overexpressing Cu,ZnSOD and catalase in combination showed significantly less expression of VCAM-1 and ICAM-1 and less number of adherent MNCs than those overexpressing either Cu,ZnSOD or catalase alone. These results suggest that combinational overexpression of Cu,ZnSOD and catalase can reduce the expression of cell adhesion molecules and inhibit the adherence of leukocyte to ECs more efficiently than overexpression of Cu,ZnSOD or catalase alone.
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Affiliation(s)
- Hong Yang
- Department of Anatomy and Physiology, Meharry Medical College, Nashville, TN 37208, USA
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47
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Schaeffer G, Levak-Frank S, Spitaler MM, Fleischhacker E, Esenabhalu VE, Wagner AH, Hecker M, Graier WF. Intercellular signalling within vascular cells under high D-glucose involves free radical-triggered tyrosine kinase activation. Diabetologia 2003; 46:773-83. [PMID: 12811469 DOI: 10.1007/s00125-003-1091-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2002] [Revised: 01/14/2003] [Indexed: 11/27/2022]
Abstract
AIMS/HYPOTHESIS Diabetes mellitus is associated with endothelial dysfunction in human arteries due to the release of superoxide anions (*O(2)(-)) that was found to occur predominantly in smooth muscle cells (SMC). This study was designed to elucidate the impact of high glucose concentration mediated radical production in SMC on EC. Pre-treatment of vascular SMC with increased D-glucose enhanced release of *O(2)(-). METHODS Microscope-based analyses of intracellular free Ca(2+) concentration (fura-2), immunohistochemistry (f-actin) and tyrosine kinase activity were performed. Furthermore, RT-PCR and Western blots were carried out. RESULTS Interaction of EC with SMC pre-exposed to high glucose concentration yielded changes in endothelial Ca(2+) signalling and polymerization of f-actin in a concentration-dependent and superoxide dismutase (SOD) sensitive manner. This interaction activated endothelial tyrosine kinase(s) but not NFkappaB and AP-1, while SOD prevented tyrosine kinase stimulation but facilitated NFkappaB and AP-1 activation. Erbstatin, herbimycin A and the src family specific kinase inhibitor PP-1 but not the protein kinase C inhibitor GF109203X prevented changes in endothelial Ca(2+) signalling and cytoskeleton organization induced by pre-exposure of SMC to high glucose concentration. Adenovirus-mediated expression of kinase-inactive c-src blunted the effect of pre-exposure of SMC to high glucose concentration on EC. CONCLUSIONS/INTERPRETATION These data suggest that SMC-derived *O(2)(-) alter endothelial cytoskeleton organization and Ca(2+) signalling via activation of c-src. The activation of c-src by SMC-derived radicals is a new concept of the mechanisms underlying vascular dysfunction in diabetes.
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Affiliation(s)
- G Schaeffer
- Department of Medical Biochemistry and Medical Molecular Biology, University of Graz, Harrachgasse 21/III, 8010 Graz, Austria
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48
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Monnier V, Girardot F, Audin W, Tricoire H. Control of oxidative stress resistance by IP3 kinase in Drosophila melanogaster. Free Radic Biol Med 2002; 33:1250-9. [PMID: 12398933 DOI: 10.1016/s0891-5849(02)01019-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oxidative damage is thought to be a major causal factor of aging, and is implicated in several human pathologies such as Alzheimer's and Parkinson's diseases. Nevertheless the genetical determinants of in vivo oxidative stress response are still poorly understood. To identify cellular components whose deregulation leads to oxidative stress resistance, we performed a genetic screen in Drosophila melanogaster. We thus identified in this screen Drosophila Inositol 1,4,5-triphosphate kinase I (D-IP3K1), a Drosophila gene homologous to mammalian IP3Ks. In vertebrates, IP3Ks phosphorylate the second messenger Inositol 1,4,5-triphosphate (IP3) to produce Inositol 1,3,4,5 tetrakiphosphate (IP4). IP3 binding to its receptor (IP3R) triggers Ca(2+) release from the endoplasmic reticulum (ER) to the cytosol, whereas IP4 physiological role remains elusive. We show here that ubiquitous overexpression of D-IP3K1 confers resistance of flies to H(2)O(2)- but not to paraquat-induced oxidative stress. Additional genetic analysis with other members of IP3 and IP4 signaling pathways led us to propose that the D-IP3K1 protective effect is mainly mediated through the reduction of IP3 level (which probably results in reduced Ca(2+) release from internal stores), rather than through the rise of IP4 level.
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49
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Hurne AM, Chai CLL, Moerman K, Waring P. Influx of calcium through a redox-sensitive plasma membrane channel in thymocytes causes early necrotic cell death induced by the epipolythiodioxopiperazine toxins. J Biol Chem 2002; 277:31631-8. [PMID: 12063251 DOI: 10.1074/jbc.m201699200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Gliotoxin, a member of the epipolythiodioxopiperazine (ETP) class of toxins, induces both apoptotic and necrotic cell death in a concentration-dependent manner. Whereas the specific trigger for apoptotic death caused by these toxins is unclear, the reactive disulfide bond in the ETP toxins is required for biological activity. Thus it is likely that it is the interaction of this disulfide moiety with macromolecules in cells that was responsible for activity of ETP toxins. Here we present evidence that necrosis induced by gliotoxin and a simple synthetic ETP toxin is largely because of an influx of extracellular calcium through a redox-sensitive calcium channel in the plasma membrane of murine thymocytes. The calcium rises are strongly dependent on the pH of the external medium and the presence of external calcium and are abrogated and/or reversed by the presence of dithiothreitol, cell impermeant glutathione, and the calcium channel blocker Ni(2+). Comparisons with thapsigargin, which indirectly causes release of calcium from internal stores, indicates that ETP toxins do not provoke calcium rises by store depletion. A mechanism of oxidation by ETP toxins of cell surface thiol groups resulting in direct entry of calcium through a redox active channel in the plasma membrane is proposed. Necrotic but not apoptotic cell death was abrogated by inhibition of calcium entry.
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Affiliation(s)
- Alanna M Hurne
- Division of Immunology and Cell Biology, John Curtin School of Medical Research, Australian National University, Canberra 0200, Australian Capital Territory, Australia
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50
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Shimoda LA, Welsh LE, Pearse DB. Inhibition of inwardly rectifying K(+) channels by cGMP in pulmonary vascular endothelial cells. Am J Physiol Lung Cell Mol Physiol 2002; 283:L297-304. [PMID: 12114190 DOI: 10.1152/ajplung.00469.2001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Endothelial barrier dysfunction is typically triggered by increased intracellular Ca(2+) concentration. Membrane-permeable analogs of guanosine 3',5'-cyclic monophosphate (cGMP) prevent disruption of endothelial cell integrity. Because membrane potential (E(m)), which influences the electrochemical gradient for Ca(2+) influx, is regulated by K(+) channels, we investigated the effect of 8-bromo-cGMP on E(m) and inwardly rectifying K(+) (K(IR)) currents in bovine pulmonary artery and microvascular endothelial cells (BPAEC and BMVEC), using whole cell patch-clamp techniques. Both cell types exhibited inward currents at potentials negative to -50 mV that were abolished by application of 10 microM Ba(2+), consistent with K(IR) current. Ba(2+) also depolarized both cell types. 8-Bromo-cGMP (10(-3) M) depolarized BPAEC and BMVEC and inhibited K(IR) current. Pretreatment with Rp-8-cPCT-cGMPS or KT-5823, protein kinase G (PKG) antagonists, did not prevent current inhibition by 8-bromo-cGMP. These data suggest that 8-bromo-cGMP induces depolarization in BPAEC and BMVEC due, in part, to PKG-independent inhibition of K(IR) current. The depolarization could be a protective mechanism that prevents endothelial cell barrier dysfunction by reducing the driving force for Ca(2+) entry.
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Affiliation(s)
- Larissa A Shimoda
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland 21224, USA.
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