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Choi ML, Chappard A, Singh BP, Maclachlan C, Rodrigues M, Fedotova EI, Berezhnov AV, De S, Peddie CJ, Athauda D, Virdi GS, Zhang W, Evans JR, Wernick AI, Zanjani ZS, Angelova PR, Esteras N, Vinokurov AY, Morris K, Jeacock K, Tosatto L, Little D, Gissen P, Clarke DJ, Kunath T, Collinson L, Klenerman D, Abramov AY, Horrocks MH, Gandhi S. Pathological structural conversion of α-synuclein at the mitochondria induces neuronal toxicity. Nat Neurosci 2022; 25:1134-1148. [PMID: 36042314 PMCID: PMC9448679 DOI: 10.1038/s41593-022-01140-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 07/12/2022] [Indexed: 11/08/2022]
Abstract
Aggregation of alpha-synuclein (α-Syn) drives Parkinson's disease (PD), although the initial stages of self-assembly and structural conversion have not been directly observed inside neurons. In this study, we tracked the intracellular conformational states of α-Syn using a single-molecule Förster resonance energy transfer (smFRET) biosensor, and we show here that α-Syn converts from a monomeric state into two distinct oligomeric states in neurons in a concentration-dependent and sequence-specific manner. Three-dimensional FRET-correlative light and electron microscopy (FRET-CLEM) revealed that intracellular seeding events occur preferentially on membrane surfaces, especially at mitochondrial membranes. The mitochondrial lipid cardiolipin triggers rapid oligomerization of A53T α-Syn, and cardiolipin is sequestered within aggregating lipid-protein complexes. Mitochondrial aggregates impair complex I activity and increase mitochondrial reactive oxygen species (ROS) generation, which accelerates the oligomerization of A53T α-Syn and causes permeabilization of mitochondrial membranes and cell death. These processes were also observed in induced pluripotent stem cell (iPSC)-derived neurons harboring A53T mutations from patients with PD. Our study highlights a mechanism of de novo α-Syn oligomerization at mitochondrial membranes and subsequent neuronal toxicity.
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Affiliation(s)
- Minee L Choi
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
- The Francis Crick Institute, London, UK
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
| | | | - Bhanu P Singh
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, UK
- School of Physics, University of Edinburgh, Edinburgh, UK
| | | | - Margarida Rodrigues
- Department of Chemistry, University of Cambridge, Cambridge, UK
- Dementia Research institute at University of Cambridge, Cambridge, UK
| | - Evgeniya I Fedotova
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Russia
- Cell Physiology and Pathology Laboratory, Orel State University, Orel, Russia
| | - Alexey V Berezhnov
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Russia
- Cell Physiology and Pathology Laboratory, Orel State University, Orel, Russia
| | - Suman De
- Department of Chemistry, University of Cambridge, Cambridge, UK
- Dementia Research institute at University of Cambridge, Cambridge, UK
| | | | - Dilan Athauda
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
- The Francis Crick Institute, London, UK
| | - Gurvir S Virdi
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
- The Francis Crick Institute, London, UK
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
| | - Weijia Zhang
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
- The Francis Crick Institute, London, UK
| | - James R Evans
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
- The Francis Crick Institute, London, UK
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
| | - Anna I Wernick
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
- The Francis Crick Institute, London, UK
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
| | - Zeinab Shadman Zanjani
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
- The Francis Crick Institute, London, UK
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
| | - Plamena R Angelova
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
| | - Noemi Esteras
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK
| | - Andrey Y Vinokurov
- Cell Physiology and Pathology Laboratory, Orel State University, Orel, Russia
| | - Katie Morris
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, UK
| | - Kiani Jeacock
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, UK
| | - Laura Tosatto
- Department of Chemistry, University of Cambridge, Cambridge, UK
- Istituto di Biofisica, National Council of Research, Trento, Italy
| | - Daniel Little
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
- NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
| | - Paul Gissen
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
- NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
| | - David J Clarke
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, UK
| | - Tilo Kunath
- Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | | | - David Klenerman
- Department of Chemistry, University of Cambridge, Cambridge, UK
- Dementia Research institute at University of Cambridge, Cambridge, UK
| | - Andrey Y Abramov
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK.
- Cell Physiology and Pathology Laboratory, Orel State University, Orel, Russia.
| | - Mathew H Horrocks
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, UK.
| | - Sonia Gandhi
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London, UK.
- The Francis Crick Institute, London, UK.
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA.
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Veuthey L, Aliotta A, Bertaggia Calderara D, Pereira Portela C, Alberio L. Mechanisms Underlying Dichotomous Procoagulant COAT Platelet Generation-A Conceptual Review Summarizing Current Knowledge. Int J Mol Sci 2022; 23:ijms23052536. [PMID: 35269679 PMCID: PMC8910683 DOI: 10.3390/ijms23052536] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/19/2022] [Accepted: 02/21/2022] [Indexed: 12/23/2022] Open
Abstract
Procoagulant platelets are a subtype of activated platelets that sustains thrombin generation in order to consolidate the clot and stop bleeding. This aspect of platelet activation is gaining more and more recognition and interest. In fact, next to aggregating platelets, procoagulant platelets are key regulators of thrombus formation. Imbalance of both subpopulations can lead to undesired thrombotic or bleeding events. COAT platelets derive from a common pro-aggregatory phenotype in cells capable of accumulating enough cytosolic calcium to trigger specific pathways that mediate the loss of their aggregating properties and the development of new adhesive and procoagulant characteristics. Complex cascades of signaling events are involved and this may explain why an inter-individual variability exists in procoagulant potential. Nowadays, we know the key agonists and mediators underlying the generation of a procoagulant platelet response. However, we still lack insight into the actual mechanisms controlling this dichotomous pattern (i.e., procoagulant versus aggregating phenotype). In this review, we describe the phenotypic characteristics of procoagulant COAT platelets, we detail the current knowledge on the mechanisms of the procoagulant response, and discuss possible drivers of this dichotomous diversification, in particular addressing the impact of the platelet environment during in vivo thrombus formation.
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Odiase E, Zhang X, Chang Y, Nelson M, Balaji U, Gu J, Zhang Q, Pan Z, Jon Spechler S, Souza RF. In Esophageal Squamous Cells From Eosinophilic Esophagitis Patients, Th2 Cytokines Increase Eotaxin-3 Secretion Through Effects on Intracellular Calcium and a Non-Gastric Proton Pump. Gastroenterology 2021; 160:2072-2088.e6. [PMID: 33581123 PMCID: PMC9013281 DOI: 10.1053/j.gastro.2021.02.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS In upper airway cells, T helper 2 cytokines that signal through interleukin-4 (IL-4) receptor-α have been shown to stimulate eotaxin-3 secretion via a nongastric proton pump (ngH+,K+ATPase). To seek novel targets for eosinophilic esophagitis (EoE) treatments, we evaluated ngH+,K+ATPase expression in EoE squamous cells, and explored molecular pathways involved in eotaxin-3 secretion by IL-4 receptor-α signaling. METHODS ngH+,K+ATPase expression in EoE cells was evaluated by quantitative real-time polymerase chain reaction and Western blotting. IL-4-stimulated eotaxin-3 secretion was measured by enzyme-linked immunosorbent assay after treatment with omeprazole, SCH 28080 (potassium-competitive acid blocker), ethylene glycol-bis(β-aminoethyl)-N,N,N',N'-tetraacetoxymethyl ester (calcium chelator), 2-aminoethoxydiphenyl borate (inhibitor of endoplasmic reticulum calcium release), verapamil, and diltiazem (L-type calcium channel inhibitors). Intracellular calcium transients were measured by Fluo-4 fluorescence. Key experiments were confirmed in EoE primary cells and in RNA sequencing datasets from mucosal biopsies of patients with EoE and controls. RESULTS EoE cells expressed ngH+,K+ATPase messenger RNA and protein. Omeprazole and SCH 28080 decreased IL-4-stimulated eotaxin-3 secretion. IL-4 increased intracellular calcium transients, and IL-4-stimulated eotaxin-3 secretion was blocked by ethylene glycol-bis(β-aminoethyl)-N,N,N',N'-tetraacetoxymethyl ester, 2-aminoethoxydiphenyl borate, verapamil, and diltiazem. The combination of omeprazole and verapamil suppressed IL-4-stimulated eotaxin-3 secretion more than either agent alone. EoE biopsies expressed higher ngH+,K+ATPase and exhibited more calcium signaling than controls. CONCLUSIONS EoE cells express a nongastric proton pump that mediates T helper 2 cytokine-stimulated eotaxin-3 secretion. IL-4 induces calcium release from the endoplasmic reticulum and calcium entry via L-type calcium channels, increasing intracellular calcium that contributes to eotaxin-3 secretion by EoE cells. L-type calcium channel inhibitors block T helper 2 cytokine-stimulated eotaxin-3 secretion, suggesting a potential role for these agents in EoE treatment.
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Affiliation(s)
- Eunice Odiase
- Department of Medicine, Center for Esophageal Diseases, Baylor University Medical Center and Center for Esophageal Research, Baylor Scott & White Research Institute, Dallas, Texas,Department of Pediatrics, Children’s Hospital of Colorado, Aurora, Colorado
| | - Xi Zhang
- Department of Medicine, Center for Esophageal Diseases, Baylor University Medical Center and Center for Esophageal Research, Baylor Scott & White Research Institute, Dallas, Texas
| | - Yan Chang
- College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, Texas
| | - Melissa Nelson
- Department of Medicine, Center for Esophageal Diseases, Baylor University Medical Center and Center for Esophageal Research, Baylor Scott & White Research Institute, Dallas, Texas
| | - Uthra Balaji
- Biostatistics Core, Baylor Scott & White Research Institute, Dallas, Texas
| | - Jinghua Gu
- Biostatistics Core, Baylor Scott & White Research Institute, Dallas, Texas
| | - Qiuyang Zhang
- Department of Medicine, Center for Esophageal Diseases, Baylor University Medical Center and Center for Esophageal Research, Baylor Scott & White Research Institute, Dallas, Texas
| | - Zui Pan
- College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, Texas
| | - Stuart Jon Spechler
- Department of Medicine, Center for Esophageal Diseases, Baylor University Medical Center and Center for Esophageal Research, Baylor Scott & White Research Institute, Dallas, Texas
| | - Rhonda F. Souza
- Department of Medicine, Center for Esophageal Diseases, Baylor University Medical Center and Center for Esophageal Research, Baylor Scott & White Research Institute, Dallas, Texas
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Mishra PK, Adameova A, Hill JA, Baines CP, Kang PM, Downey JM, Narula J, Takahashi M, Abbate A, Piristine HC, Kar S, Su S, Higa JK, Kawasaki NK, Matsui T. Guidelines for evaluating myocardial cell death. Am J Physiol Heart Circ Physiol 2019; 317:H891-H922. [PMID: 31418596 DOI: 10.1152/ajpheart.00259.2019] [Citation(s) in RCA: 135] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cell death is a fundamental process in cardiac pathologies. Recent studies have revealed multiple forms of cell death, and several of them have been demonstrated to underlie adverse cardiac remodeling and heart failure. With the expansion in the area of myocardial cell death and increasing concerns over rigor and reproducibility, it is important and timely to set a guideline for the best practices of evaluating myocardial cell death. There are six major forms of regulated cell death observed in cardiac pathologies, namely apoptosis, necroptosis, mitochondrial-mediated necrosis, pyroptosis, ferroptosis, and autophagic cell death. In this article, we describe the best methods to identify, measure, and evaluate these modes of myocardial cell death. In addition, we discuss the limitations of currently practiced myocardial cell death mechanisms.
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Affiliation(s)
- Paras K Mishra
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Adriana Adameova
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Comenius University of Bratislava, Bratislava, Slovakia
| | - Joseph A Hill
- Departments of Medicine (Cardiology) and Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Christopher P Baines
- Department of Biomedical Sciences, Dalton Cardiovascular Research Center, University of Missouri-Columbia, Columbia, Missouri
| | - Peter M Kang
- Cardiovascular Division, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - James M Downey
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, Alabama
| | - Jagat Narula
- Mount Sinai Heart, Icahn School of Medicine at Mount Sinai Hospital, New York, New York
| | - Masafumi Takahashi
- Division of Inflammation Research, Center of Molecular Medicine, Jichi Medical University, Tochigi, Japan
| | - Antonio Abbate
- Virginia Commonwealth University, Pauley Heart Center, Richmond, Virginia
| | - Hande C Piristine
- Department of Medicine (Cardiology), University of Texas Southwestern Medical Center, Dallas, Texas
| | - Sumit Kar
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska
| | - Shi Su
- Cardiovascular Division, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Jason K Higa
- Department of Anatomy, Biochemistry, and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii
| | - Nicholas K Kawasaki
- Department of Anatomy, Biochemistry, and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii
| | - Takashi Matsui
- Department of Anatomy, Biochemistry, and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii
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Angelova PR, Vinogradova D, Neganova ME, Serkova TP, Sokolov VV, Bachurin SO, Shevtsova EF, Abramov AY. Pharmacological Sequestration of Mitochondrial Calcium Uptake Protects Neurons Against Glutamate Excitotoxicity. Mol Neurobiol 2018; 56:2244-2255. [PMID: 30008072 PMCID: PMC6394642 DOI: 10.1007/s12035-018-1204-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 06/26/2018] [Indexed: 12/14/2022]
Abstract
Neuronal excitotoxicity which is induced by exposure to excessive extracellular glutamate is shown to be involved in neuronal cell death in acute brain injury and a number of neurological diseases. High concentration of glutamate induces calcium deregulation which results in mitochondrial calcium overload and mitochondrial depolarization that triggers the mechanism of cell death. Inhibition of mitochondrial calcium uptake could be potentially neuroprotective but complete inhibition of mitochondrial calcium uniporter could result in the loss of some physiological processes linked to Ca2+ in mitochondria. Here, we found that a novel compound, TG-2112x, can inhibit only the lower concentrations mitochondrial calcium uptake (induced by 100 nM-5 μM) but not the uptake induced by higher concentrations of calcium (10 μM and higher). This effect was not associated with changes in mitochondrial membrane potential and cellular respiration. However, a pre-treatment of neurons with TG-2112x protected the neurons against calcium overload upon application of toxic concentrations of glutamate. Thus, sequestration of mitochondrial calcium uptake protected the neurons against glutamate-induced mitochondrial depolarization and cell death. In our hands, TG-2112x was also protective against ionomycin-induced cell death. Hence, low rate mitochondrial calcium uptake plays an underestimated role in mitochondrial function, and its inhibition could protect neurons against calcium overload and cell death in glutamate excitotoxicity.
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Affiliation(s)
- Plamena R Angelova
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Darya Vinogradova
- Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka, 142432, Russia
| | - Margarita E Neganova
- Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka, 142432, Russia
| | - Tatiana P Serkova
- Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka, 142432, Russia
| | - Vladimir V Sokolov
- Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka, 142432, Russia
| | - Sergey O Bachurin
- Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka, 142432, Russia
| | - Elena F Shevtsova
- Institute of Physiologically Active Compounds Russian Academy of Sciences, Chernogolovka, 142432, Russia.
| | - Andrey Y Abramov
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK.
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Mitochondrial calcium imbalance in Parkinson’s disease. Neurosci Lett 2018; 663:86-90. [DOI: 10.1016/j.neulet.2017.08.044] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 08/11/2017] [Accepted: 08/16/2017] [Indexed: 12/22/2022]
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Abstract
Neurohormonal activation with attendant aldosteronism contributes to the clinical appearance of congestive heart failure (CHF). Aldosteronism is intrinsically coupled to Zn and Ca dyshomeostasis, in which consequent hypozincemia compromises Zn homeostasis and Zn-based antioxidant defenses that contribute to the CHF prooxidant phenotype. Ionized hypocalcemia leads to secondary hyperparathyroidism with parathyroid hormone-mediated Ca overloading of diverse cells, including cardiomyocytes. When mitochondrial Ca overload exceeds a threshold, myocyte necrosis follows. The reciprocal regulation involving cytosolic free [Zn]i as antioxidant and [Ca]i as prooxidant can be uncoupled in favor of Zn-based antioxidant defenses. Increased [Zn]i acts as a multifaceted antioxidant by: (1) inhibiting Ca entry through L-type channels and hence cardioprotectant from the Ca-driven mitochondriocentric signal-transducer effector pathway to nonischemic necrosis, (2) serving as catalytic regulator of Cu/Zn-superoxide dismutase, and (3) activating its cytosolic sensor, metal-responsive transcription factor that regulates the expression of relevant antioxidant defense genes. Albeit present in subnanomolar range, increased cytosolic free [Zn]i enhances antioxidant capacity that confers cardioprotection. It can be achieved exogenously by ZnSO4 supplementation or endogenously using a β3-receptor agonist (eg, nebivolol) that enhances NO generation to release inactive cytosolic Zn bound to metallothionein. By recognizing the pathophysiologic relevance of Zn dyshomeostasis in the prooxidant CHF phenotype and by exploiting the pharmacophysiologic potential of [Zn]i as antioxidant, vulnerable cardiomyocytes under assault from neurohormonal activation can be protected and the myocardium spared from adverse structural remodeling.
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Holmes S, Abbassi B, Su C, Singh M, Cunningham RL. Oxidative stress defines the neuroprotective or neurotoxic properties of androgens in immortalized female rat dopaminergic neuronal cells. Endocrinology 2013; 154:4281-92. [PMID: 23959938 PMCID: PMC3800758 DOI: 10.1210/en.2013-1242] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Males have a higher risk for developing Parkinson's disease and parkinsonism after ischemic stroke than females. Although estrogens have been shown to play a neuroprotective role in Parkinson's disease, there is little information on androgens' actions on dopamine neurons. In this study, we examined the effects of androgens under conditions of oxidative stress to determine whether androgens play a neuroprotective or neurotoxic role in dopamine neuronal function. Mitochondrial function, cell viability, intracellular calcium levels, and mitochondrial calcium influx were examined in response to androgens under both nonoxidative and oxidative stress conditions. Briefly, N27 dopaminergic cells were exposed to the oxidative stressor, hydrogen peroxide, and physiologically relevant levels of testosterone or dihydrotestosterone, applied either before or after oxidative stress exposure. Androgens, alone, increased mitochondrial function via a calcium-dependent mechanism. Androgen pretreatment protected cells from oxidative stress-induced cell death. However, treatment with androgens after the oxidative insult increased cell death, and these effects were, in part, mediated by calcium influx into the mitochondria. Interestingly, the negative effects of androgens were not blocked by either androgen or estrogen receptor antagonists. Instead, a putative membrane-associated androgen receptor was implicated. Overall, our results indicate that androgens are neuroprotective when oxidative stress levels are minimal, but when oxidative stress levels are elevated, androgens exacerbate oxidative stress damage.
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Affiliation(s)
- Shaletha Holmes
- PhD, Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, 3400 Camp Bowie Boulevard, Fort Worth, Texas 76107-2699.
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Almassy J, Yule DI. Photolysis of caged compounds: studying Ca(2+) signaling and activation of Ca(2+)-dependent ion channels. Cold Spring Harb Protoc 2013; 2013:2013/1/pdb.top066076. [PMID: 23282631 DOI: 10.1101/pdb.top066076] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
A wide variety of signaling molecules have been chemically modified by conjugation to a photolabile chromophore to render the substance temporarily biologically inert. Subsequent exposure to ultraviolet (UV) light can release the active moiety from the "caged" precursor in an experimentally controlled manner. This allows the concentration of active molecule to be precisely manipulated in both time and space. These techniques are particularly useful in experimental protocols designed to investigate the mechanisms underlying Ca(2+) signaling and the activation of Ca(2+)-dependent effectors.
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Affiliation(s)
- Janos Almassy
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642, USA
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Polysaccharides of Dendrobium officinale inhibit TNF-α-induced apoptosis in A-253 cell line. Inflamm Res 2012; 62:313-24. [DOI: 10.1007/s00011-012-0584-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 12/05/2012] [Accepted: 12/10/2012] [Indexed: 01/10/2023] Open
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