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Heckman CA, Ademuyiwa OM, Cayer ML. How filopodia respond to calcium in the absence of a calcium-binding structural protein: non-channel functions of TRP. Cell Commun Signal 2022; 20:130. [PMID: 36028898 PMCID: PMC9414478 DOI: 10.1186/s12964-022-00927-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Accepted: 06/21/2022] [Indexed: 11/18/2022] Open
Abstract
Background For many cell types, directional locomotion depends on their maintaining filopodia at the leading edge. Filopodia lack any Ca2+-binding structural protein but respond to store-operated Ca2+ entry (SOCE). Methods SOCE was induced by first replacing the medium with Ca2+-free salt solution with cyclopiazonic acid (CPA). This lowers Ca2+ in the ER and causes stromal interacting molecule (STIM) to be translocated to the cell surface. After this priming step, CPA was washed out, and Ca2+ influx restored by addition of extracellular Ca2+. Intracellular Ca2+ levels were measured by calcium orange fluorescence. Regulatory mechanisms were identified by pharmacological treatments. Proteins mediating SOCE were localized by immunofluorescence and analyzed after image processing. Results Depletion of the ER Ca2+ increased filopodia prevalence briefly, followed by a spontaneous decline that was blocked by inhibitors of endocytosis. Intracellular Ca2+ increased continuously for ~ 50 min. STIM and a transient receptor potential canonical (TRPC) protein were found in separate compartments, but an aquaporin unrelated to SOCE was present in both. STIM1- and TRPC1-bearing vesicles were trafficked on microtubules. During depletion, STIM1 migrated to the surface where it coincided with Orai in punctae, as expected. TRPC1 was partially colocalized with Vamp2, a rapidly releasable pool marker, and with phospholipases (PLCs). TRPC1 retreated to internal compartments during ER depletion. Replenishment of extracellular Ca2+ altered the STIM1 distribution, which came to resemble that of untreated cells. Vamp2 and TRPC1 underwent exocytosis and became homogeneously distributed on the cell surface. This was accompanied by an increased prevalence of filopodia, which was blocked by inhibitors of TRPC1/4/5 and endocytosis. Conclusions Because the media were devoid of ligands that activate receptors during depletion and Ca2+ replenishment, we could attribute filopodia extension to SOCE. We propose that the Orai current stimulates exocytosis of TRPC-bearing vesicles, and that Ca2+ influx through TRPC inhibits PLC activity. This allows regeneration of the substrate, phosphatidylinositol 4,5 bisphosphate (PIP2), a platform for assembling proteins, e. g. Enabled and IRSp53. TRPC contact with PLC is required but is broken by TRPC dissemination. This explains how STIM1 regulates the cell’s ability to orient itself in response to attractive or repulsive cues. Video Abstract
Supplementary Information The online version contains supplementary material available at 10.1186/s12964-022-00927-y.
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Affiliation(s)
- C A Heckman
- Department of Biological Sciences, 217 Life Science Building, Bowling Green State University, Bowling Green, OH, 43403-0001, USA.
| | - O M Ademuyiwa
- Department of Biological Sciences, 217 Life Science Building, Bowling Green State University, Bowling Green, OH, 43403-0001, USA
| | - M L Cayer
- Center for Microscopy and Microanalysis, Bowling Green State University, Bowling Green, OH, 43403, USA
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Alphonse N, Wanford JJ, Voak AA, Gay J, Venkhaya S, Burroughs O, Mathew S, Lee T, Evans SL, Zhao W, Frowde K, Alrehaili A, Dickenson RE, Munk M, Panina S, Mahmood IF, Llorian M, Stanifer ML, Boulant S, Berchtold MW, Bergeron JRC, Wack A, Lesser CF, Odendall C. A family of conserved bacterial virulence factors dampens interferon responses by blocking calcium signaling. Cell 2022; 185:2354-2369.e17. [PMID: 35568036 PMCID: PMC9596379 DOI: 10.1016/j.cell.2022.04.028] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 03/22/2022] [Accepted: 04/20/2022] [Indexed: 02/06/2023]
Abstract
Interferons (IFNs) induce an antimicrobial state, protecting tissues from infection. Many viruses inhibit IFN signaling, but whether bacterial pathogens evade IFN responses remains unclear. Here, we demonstrate that the Shigella OspC family of type-III-secreted effectors blocks IFN signaling independently of its cell death inhibitory activity. Rather, IFN inhibition was mediated by the binding of OspC1 and OspC3 to the Ca2+ sensor calmodulin (CaM), blocking CaM kinase II and downstream JAK/STAT signaling. The growth of Shigella lacking OspC1 and OspC3 was attenuated in epithelial cells and in a murine model of infection. This phenotype was rescued in both models by the depletion of IFN receptors. OspC homologs conserved in additional pathogens not only bound CaM but also inhibited IFN, suggesting a widespread virulence strategy. These findings reveal a conserved but previously undescribed molecular mechanism of IFN inhibition and demonstrate the critical role of Ca2+ and IFN targeting in bacterial pathogenesis.
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Affiliation(s)
- Noémie Alphonse
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King's College London, London, UK; Immunoregulation Laboratory, Francis Crick Institute, London, UK
| | - Joseph J Wanford
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King's College London, London, UK
| | - Andrew A Voak
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King's College London, London, UK
| | - Jack Gay
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King's College London, London, UK
| | - Shayla Venkhaya
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King's College London, London, UK
| | - Owen Burroughs
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King's College London, London, UK
| | - Sanjana Mathew
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King's College London, London, UK
| | - Truelian Lee
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Sasha L Evans
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | - Weiting Zhao
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King's College London, London, UK
| | - Kyle Frowde
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King's College London, London, UK
| | - Abrar Alrehaili
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King's College London, London, UK
| | - Ruth E Dickenson
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King's College London, London, UK
| | - Mads Munk
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Svetlana Panina
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Ishraque F Mahmood
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King's College London, London, UK
| | - Miriam Llorian
- Bioinformatics and Biostatistics, The Francis Crick Institute, London, UK
| | - Megan L Stanifer
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, FL, USA
| | - Steeve Boulant
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, FL, USA
| | | | - Julien R C Bergeron
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | - Andreas Wack
- Immunoregulation Laboratory, Francis Crick Institute, London, UK
| | - Cammie F Lesser
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA, USA; Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Charlotte Odendall
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King's College London, London, UK.
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Fredriksson MI. Effect of Priming in Subpopulations of Peripheral Neutrophils From Patients with Chronic Periodontitis. J Periodontol 2012; 83:1192-9. [DOI: 10.1902/jop.2012.110584] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Hamanaka K, Jian MY, Townsley MI, King JA, Liedtke W, Weber DS, Eyal FG, Clapp MM, Parker JC. TRPV4 channels augment macrophage activation and ventilator-induced lung injury. Am J Physiol Lung Cell Mol Physiol 2010; 299:L353-62. [PMID: 20562229 PMCID: PMC2951075 DOI: 10.1152/ajplung.00315.2009] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Accepted: 06/11/2010] [Indexed: 12/24/2022] Open
Abstract
We have previously implicated transient receptor potential vanilloid 4 (TRPV4) channels and alveolar macrophages in initiating the permeability increase in response to high peak inflation pressure (PIP) ventilation. Alveolar macrophages were harvested from TRPV4(-/-) and TRPV4(+/+) mice and instilled in the lungs of mice of the opposite genotype. Filtration coefficients (K(f)) measured in isolated perfused lungs after ventilation with successive 30-min periods of 9, 25, and 35 cmH(2)O PIP did not significantly increase in lungs from TRPV4(-/-) mice but increased >2.2-fold in TRPV4(+/+) lungs, TRPV4(+/+) lungs instilled with TRPV4(-/-) macrophages, and TRPV4(-/-) lungs instilled with TRPV4(+/+) macrophages after ventilation with 35 cmH(2)O PIP. Activation of TRPV4 with 4-alpha-phorbol didecanoate (4alphaPDD) significantly increased intracellular calcium, superoxide, and nitric oxide production in TRPV4(+/+) macrophages but not TRPV4(-/-) macrophages. Cross-sectional areas increased nearly 3-fold in TRPV4(+/+) macrophages compared with TRPV4(-/-) macrophages after 4alphaPDD. Immunohistochemistry staining of lung tissue for nitrotyrosine revealed increased amounts in high PIP ventilated TRPV4(+/+) lungs compared with low PIP ventilated TRPV4(+/+) or high PIP ventilated TRPV4(-/-) lungs. Thus TRPV4(+/+) macrophages restored susceptibility of TRPV4(-/-) lungs to mechanical injury. A TRPV4 agonist increased intracellular calcium and reactive oxygen and nitrogen species in harvested TRPV4(+/+) macrophages but not TRPV4(-/-) macrophages. K(f) increases correlated with tissue nitrotyrosine, a marker of peroxynitrite production.
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Affiliation(s)
- Kazutoshi Hamanaka
- Department of Physiology, University of South Alabama, Mobile, Alabama 36688, USA
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5
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Local control of mitochondrial membrane potential, permeability transition pore and reactive oxygen species by calcium and calmodulin in rat ventricular myocytes. J Mol Cell Cardiol 2009; 46:989-97. [PMID: 19318235 DOI: 10.1016/j.yjmcc.2008.12.022] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 12/24/2008] [Accepted: 12/30/2008] [Indexed: 11/21/2022]
Abstract
Calmodulin (CaM) and Ca(2+)/CaM-dependent protein kinase II (CaMKII) play important roles in the development of heart failure. In this study, we evaluated the effects of CaM on mitochondrial membrane potential (DeltaPsi(m)), permeability transition pore (mPTP) and the production of reactive oxygen species (ROS) in permeabilized myocytes; our findings are as follows. (1) CaM depolarized DeltaPsi(m) dose-dependently, but this was prevented by an inhibitor of CaM (W-7) or CaMKII (autocamtide 2-related inhibitory peptide (AIP)). (2) CaM accelerated calcein leakage from mitochondria, indicating the opening of mPTP, however this was prevented by AIP. (3) Cyclosporin A (an inhibitor of the mPTP) inhibited both CaM-induced DeltaPsi(m) depolarization and calcein leakage. (4) CaM increased mitochondrial ROS, which was related to DeltaPsi(m) depolarization and the opening of mPTP. (5) Chelating of cytosolic Ca(2+) by BAPTA, the depletion of SR Ca(2+) by thapsigargin (an inhibitor of SERCA) and the inhibition of mitochondrial Ca(2+) uniporter by Ru360 attenuated the effects of CaM on mitochondrial function. (6) CaM accelerated Ca(2+) extrusion from mitochondria. We conclude that CaM/CaMKII depolarized DeltaPsi(m) and opened mPTP by increasing ROS production, and these effects were strictly regulated by the local increase in cytosolic Ca(2+) concentration, initiated by Ca(2+) releases from the SR. In addition, CaM was involved in the regulation of mitochondrial Ca(2+) homeostasis.
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Han JH, Kim YJ, Han ES, Lee CS. Prevention of 7-ketocholesterol-induced mitochondrial damage and cell death by calmodulin inhibition. Brain Res 2006; 1137:11-9. [PMID: 17224136 DOI: 10.1016/j.brainres.2006.12.041] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2006] [Revised: 11/26/2006] [Accepted: 12/14/2006] [Indexed: 12/31/2022]
Abstract
Oxysterols such as 7-ketocholesterol and 25-hydroxycholesterol formed under enhanced oxidative stress in the brain are suggested to induce neuronal cell death. The present study investigated the effect of calmodulin antagonists (trifluoperazine, W-7 and calmidazolium) against the cytotoxicity of 7-ketocholesterol in relation to the mitochondria-mediated cell death process and oxidative stress. PC12 cells exposed to 7-ketocholesterol revealed nuclear damage, decrease in the mitochondrial transmembrane potential, cytosolic accumulation of cytochrome c, activation of caspase-3, increase in the formation of reactive oxygen species and depletion of GSH. N-Acetylcysteine, trolox, carboxy-PTIO and Mn-TBAP reduced the cytotoxic effect of 7-ketocholesterol. Calmodulin antagonists attenuated the 7-ketocholesterol-induced nuclear damage, formation of the mitochondrial permeability transition and cell viability loss in PC12 cells. The results suggest that calmodulin antagonists may prevent the 7-ketocholesterol-induced viability loss in PC12 cells by suppressing formation of the mitochondrial permeability transition, leading to the release of cytochrome c and subsequent activation of caspase-3. The effects seem to be ascribed to their depressant action on the formation of reactive oxygen species and depletion of GSH. The findings suggest that calmodulin inhibition may exhibit a protective effect against the neurotoxicity of 7-ketocholesterol.
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Affiliation(s)
- Jeong Ho Han
- Department of Neurology, Seoul Veterans Hospital, Seoul 134-791, South Korea
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Lee CS, Park WJ, Han ES, Bang H. Differential Modulation of 7-Ketocholesterol Toxicity Against PC12 Cells by Calmodulin Antagonists and Ca2+ Channel Blockers. Neurochem Res 2006; 32:87-98. [PMID: 17151911 DOI: 10.1007/s11064-006-9230-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2006] [Accepted: 11/16/2006] [Indexed: 12/24/2022]
Abstract
The present study assessed the influence of intracellular Ca2+ and calmodulin against the neurotoxicity of oxysterol 7-ketocholesterol in relation to the mitochondria-mediated cell death process and oxidative stress in PC12 cells. Calmodulin antagonists calmidazolium and W-7 prevented the 7-ketocholesterol-induced mitochondrial damage, leading to caspase-3 activation and cell death, whereas Ca2+ channel blocker nicardipine, mitochondrial Ca2+ uptake inhibitor ruthenium red, and cell permeable Ca2+ chelator BAPTA-AM did not reduce it. Exposure of PC12 cells to 7-ketocholesterol caused elevation of intracellular Ca2+ levels. Unlike cell injury, calmodulin antagonists, nicardipine, and BAPTA-AM prevented the 7-ketocholesterol-induced elevations of intracellular Ca2+ levels. The results show that the cytotoxicity of 7-ketocholesterol seems to be modulated by calmodulin rather than changes in intracellular Ca2+ levels. Calmodulin antagonists may prevent the cytotoxicity of 7-ketocholesterol by suppressing the mitochondrial permeability transition formation, which is associated with the increased formation of reactive oxygen species and the depletion of GSH.
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Affiliation(s)
- Chung Soo Lee
- Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul 156-756, South Korea.
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Smallwood HS, Shi L, Squier TC. Increases in calmodulin abundance and stabilization of activated inducible nitric oxide synthase mediate bacterial killing in RAW 264.7 macrophages. Biochemistry 2006; 45:9717-26. [PMID: 16893173 DOI: 10.1021/bi060485p] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The rapid activation of macrophages in response to bacterial antigens is central to the innate immune system that permits the recognition and killing of pathogens to limit infection. To understand regulatory mechanisms underlying macrophage activation, we have investigated changes in the abundance of calmodulin (CaM) and iNOS in response to the bacterial cell wall component lipopolysaccharide (LPS) using RAW 264.7 macrophages. Critical to these measurements was the ability to differentiate free iNOS from the CaM-bound (active) form of iNOS associated with nitric oxide generation. We observe a rapid 2-fold increase in CaM abundance during the first 30 min that is blocked by inhibition of either NFkappaB nuclear translocation or protein synthesis. A similar 2-fold increase in the abundance of the complex between CaM and iNOS is observed with the same time dependence. In contrast, there are no detectable increases in the CaM-free (i.e., inactive) form of iNOS within the first 2 h; it remains at a very low abundance during the initial phase of macrophage activation. Increasing cellular CaM levels in stably transfected macrophages results in a corresponding increase in the abundance of the CaM/iNOS complex that promotes effective bacterial killing following infection by Salmonella typhimurium. Thus, LPS-dependent increases in CaM abundance function in the stabilization and activation of iNOS on the rapid time scale associated with macrophage activation and bacterial killing. These results explain how CaM and iNOS coordinately function to form a stable complex that is part of a rapid host response that functions within the first 30 min following bacterial infection to upregulate the innate immune system involving macrophage activation.
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Affiliation(s)
- Heather S Smallwood
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, USA
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Weber TJ, Smallwood HS, Kathmann LE, Markillie LM, Squier TC, Thrall BD. Functional link between TNF biosynthesis and CaM-dependent activation of inducible nitric oxide synthase in RAW 264.7 macrophages. Am J Physiol Cell Physiol 2006; 290:C1512-20. [PMID: 16421203 DOI: 10.1152/ajpcell.00527.2005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Inflammatory responses stimulated by bacterial endotoxin LPS involve Ca2+-mediated signaling, yet the cellular sensors that determine cell fate in response to LPS remain poorly understood. We report that exposure of RAW 264.7 macrophage-like cells to LPS induces a rapid increase in CaM abundance, which is associated with the modulation of the inflammatory response. Increases in CaM abundance precede nuclear localization of key transcription factors (i.e., NF-κB p65 subunit, phospho-c-Jun, Sp1) and subsequent increases in the proinflammatory cytokine TNF-α and inducible nitric oxide synthase (iNOS). Cellular apoptosis after LPS challenge is blocked upon inhibition of iNOS activity using the pharmacological inhibitor 1400W. LPS-mediated iNOS expression and apoptosis also were inhibited by siRNA-mediated silencing of TNF induction, indicating TNF induction both precedes and is necessary for subsequent regulation of iNOS expression. Increasing the level of cellular CaM by stable transfection results in reductions in LPS-induced expression of TNF and iNOS, along with reduced activation of their transcriptional regulators and concomitant protection against apoptosis. Thus the level of CaM available for Ca2+-dependent signaling regulation plays a key role in determining the expression of the proinflammatory and proapoptotic cascade during cellular activation by LPS. These results indicate a previously unrecognized central role for CaM in maintaining cellular homeostasis in response to LPS such that, under resting conditions, cellular concentrations of CaM are sufficient to inhibit the biosynthesis of proinflammatory mediators associated with macrophage activation. Although CaM and iNOS protein levels are coordinately increased as part of the oxidative burst, limiting cellular concentrations of CaM due to association with iNOS (and other high-affinity binders) commit the cell to an unchecked inflammatory cascade leading to apoptosis.
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Affiliation(s)
- Thomas J Weber
- Cell Biology and Biochemistry Group, Pacific Northwest National Laboratory, 790 Sixth St., Richland, WA 99354, USA
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Talati M, Meyrick B, Peebles RS, Davies SS, Dworski R, Mernaugh R, Mitchell D, Boothby M, Roberts LJ, Sheller JR. Oxidant stress modulates murine allergic airway responses. Free Radic Biol Med 2006; 40:1210-9. [PMID: 16545689 DOI: 10.1016/j.freeradbiomed.2005.11.012] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2005] [Accepted: 11/11/2005] [Indexed: 10/25/2022]
Abstract
The allergic inflammation occurring in asthma is believed to be accompanied by the production of free radicals. To investigate the role of free radicals and the cells affected we turned to a murine model of allergic inflammation produced by sensitization to ovalbumin with subsequent aerosol challenge. We examined oxidant stress by measuring and localizing the sensitive and specific marker of lipid peroxidation, the F2-isoprostanes. F2-isoprostanes in whole lung increased from 0.30 +/- 0.08 ng/lung at baseline to a peak of 0.061 +/- 0.09 ng/lung on the ninth day of daily aerosol allergen challenge. Increased immunoreactivity to 15-F2t-IsoP (8-iso-PGF2alpha) or to isoketal protein adducts was found in epithelial cells 24 h after the first aerosol challenge and at 5 days in macrophages. Collagen surrounding airways and blood vessels, and airway and vascular smooth muscle, also exhibited increased immunoreactivity after ovalbumin challenge. Dietary vitamin E restriction in conjunction with allergic inflammation led to increased whole lung F2-isoprostanes while supplemental vitamin E suppressed their formation. Similar changes in immunoreactivity to F2-isoprostanes were seen. Airway responsiveness to methacholine was also increased by vitamin E depletion and decreased slightly by supplementation with the antioxidant. Our findings indicate that allergic airway inflammation in mice is associated with an increase in oxidant stress, which is most striking in airway epithelial cells and macrophages. Oxidant stress plays a role in the production of airway responsiveness.
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Affiliation(s)
- Megha Talati
- Department of Medicine, T 1217 MCN, Vanderbilt University, Nashville, TN 37232, USA
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Ori Y, Herman M, Chagnac A, Malachi T, Gafter U, Korzets A. Spontaneous DNA repair in human mononuclear cells is calcium-dependent. Biochem Biophys Res Commun 2005; 336:842-6. [PMID: 16157301 DOI: 10.1016/j.bbrc.2005.08.186] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2005] [Accepted: 08/24/2005] [Indexed: 11/28/2022]
Abstract
Spontaneous DNA repair in peripheral blood mononuclear cells (PBMC) has been recently described. The aim of this study was to evaluate whether spontaneous DNA repair is Ca(2+)-dependent, as in vitro-stimulated DNA repair. Spontaneous DNA repair in PBMC was measured in a 1mM Ca2+ medium. The effect of extracellular Ca2+ chelation by EGTA, intracellular Ca2+ chelation by bapta-AM, and Ca2+ loading by the ionophore A23187 was examined. The signal transduction pathway was evaluated by inhibiting protein tyrosine kinase with genistein, calmodulin with W7, and calcineurin with cyclosporin A and tacrolimus. Extracellular Ca2+ chelation had no effect on spontaneous DNA repair, while both intracellular chelation and calcium overloading inhibited the DNA repair. Inhibition of protein tyrosine kinase, calmodulin or calcineurin reduced DNA repair. In conclusion, spontaneous DNA repair is mainly Ca(2+)-dependent at a narrow range of intracellular Ca2+ concentrations. The signal transduction cascade includes protein tyrosine kinase, calmodulin, and calcineurin.
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Affiliation(s)
- Yaacov Ori
- Department of Nephrology and Hypertension, Rabin Medical Center, Petah-Tikva, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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Ten Broeke R, Blalock JE, Nijkamp FP, Folkerts G. Calcium sensors as new therapeutic targets for asthma and chronic obstructive pulmonary disease. Clin Exp Allergy 2004; 34:170-6. [PMID: 14987293 DOI: 10.1111/j.1365-2222.2004.01908.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- R Ten Broeke
- Department of Pharmacology and Pathophysiology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands.
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