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Theofanous T, Kourti M. Abrogating Oxidative Stress as a Therapeutic Strategy against Parkinson’s Disease: A Mini Review of the Recent Advances on Natural Therapeutic Antioxidant and Neuroprotective Agents. Med Chem 2022; 18:772-783. [DOI: 10.2174/1573406418666220304222401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/15/2021] [Accepted: 12/23/2021] [Indexed: 11/22/2022]
Abstract
Background:
Reactive oxygen species (ROS) play a vital role in cell signaling when maintained at low concentrations. However, when ROS production exceeds the neutralizing capacity of endogenous antioxidants, oxidative stress is observed, which has been shown to contribute to neurodegenerative diseases such as Parkinson's disease (PD). PD is a progressive disorder characterized by the loss of dopaminergic neurons from the striatum, which leads to motor and nonmotor symptoms. Although the complex interplay of mechanisms responsible are yet to be fully understood, oxidative stress was found to be positively associated with PD. Despite active research, currently proposed regimens mainly focus on regulating dopamine metabolism within the brain, even though these treatments have shown limited long-term efficacy and several side effects. Due to the implication of oxidative stress in the pathophysiology of PD, natural antioxidant compounds have attracted interest as potential therapeutics over the last years, with a more favorable anticipated safety profile due to their natural origin. Therefore, natural antioxidants are currently being explored as promising anti-PD agents.
Objective:
In this mini review, emphasis was given to presently studied natural antioxidant and neuroprotective agents that have shown positive results in PD animal models.
Methods:
For this purpose, recent scientific articles were reviewed and discussed, with the aim to highlight the most up-to-date advances on PD treatment strategies related to oxidative stress.
Results:
A plethora of natural compounds are actively being explored against PD, including kaemferol, icaritin, artemisinin, and α-bisabolol, with promising results. Most of these compounds have shown adequate neuroprotective ability along with redox balance restoration, normalized mitochondrial function and limitation of the oxidative damage.
Conclusion:
In conclusion, natural antioxidants may be the way forward to novel treatments against PD, when the limitations of correct dosing and appropriate combinations are resolved.
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Affiliation(s)
| | - Malamati Kourti
- Angiogenesis and Cancer Drug discovery group, Basic and Translational Cancer Research Centre, Department of Life Sciences, European University Cyprus, Nicosia, 2404, Cyprus
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2
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Spiers JG, Steinert JR. Nitrergic modulation of ion channel function in regulating neuronal excitability. Channels (Austin) 2021; 15:666-679. [PMID: 34802368 PMCID: PMC8632290 DOI: 10.1080/19336950.2021.2002594] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Nitric oxide (NO) signaling in the brain provides a wide range of functional properties in response to neuronal activity. NO exerts its effects through different signaling pathways, namely, through the canonical soluble guanylyl cyclase-mediated cGMP production route and via post-translational protein modifications. The latter pathways comprise cysteine S-nitrosylation and 3-nitrotyrosination of distinct tyrosine residues. Many ion channels are targeted by one or more of these signaling routes, which leads to their functional regulation under physiological conditions or facilities their dysfunction leading to channelopathies in many pathologies. The resulting alterations in ion channel function changes neuronal excitability, synaptic transmission, and action potential propagation. Transient and activity-dependent NO production mediates reversible ion channel modifications via cGMP and S-nitrosylation signaling, whereas more pronounced and longer-term NO production during conditions of elevated oxidative stress leads to increasingly cumulative and irreversible protein 3-nitrotyrosination. The complexity of this regulation and vast variety of target ion channels and their associated functional alterations presents a challenging task in assessing and understanding the role of NO signaling in physiology and disease.
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Affiliation(s)
- Jereme G Spiers
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - Joern R Steinert
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK
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3
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Zinc in the Brain: Friend or Foe? Int J Mol Sci 2020; 21:ijms21238941. [PMID: 33255662 PMCID: PMC7728061 DOI: 10.3390/ijms21238941] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/22/2020] [Accepted: 11/24/2020] [Indexed: 12/12/2022] Open
Abstract
Zinc is a trace metal ion in the central nervous system that plays important biological roles, such as in catalysis, structure, and regulation. It contributes to antioxidant function and the proper functioning of the immune system. In view of these characteristics of zinc, it plays an important role in neurophysiology, which leads to cell growth and cell proliferation. However, after brain disease, excessively released and accumulated zinc ions cause neurotoxic damage to postsynaptic neurons. On the other hand, zinc deficiency induces degeneration and cognitive decline disorders, such as increased neuronal death and decreased learning and memory. Given the importance of balance in this context, zinc is a biological component that plays an important physiological role in the central nervous system, but a pathophysiological role in major neurological disorders. In this review, we focus on the multiple roles of zinc in the brain.
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Aizenman E, Loring RH, Reynolds IJ, Rosenberg PA. The Redox Biology of Excitotoxic Processes: The NMDA Receptor, TOPA Quinone, and the Oxidative Liberation of Intracellular Zinc. Front Neurosci 2020; 14:778. [PMID: 32792905 PMCID: PMC7393236 DOI: 10.3389/fnins.2020.00778] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 07/02/2020] [Indexed: 12/14/2022] Open
Abstract
This special issue of Frontiers in Neuroscience-Neurodegeneration celebrates the 50th anniversary of John Olney's seminal work introducing the concept of excitotoxicity as a mechanism for neuronal cell death. Since that time, fundamental research on the pathophysiological activation of glutamate receptors has played a central role in our understanding of excitotoxic cellular signaling pathways, leading to the discovery of many potential therapeutic targets in the treatment of acute or chronic/progressive neurodegenerative disorders. Importantly, excitotoxic signaling processes have been found repeatedly to be closely intertwined with oxidative cellular cascades. With this in mind, this review looks back at long-standing collaborative efforts by the authors linking cellular redox status and glutamate neurotoxicity, focusing first on the discovery of the redox modulatory site of the N-methyl-D-aspartate (NMDA) receptor, followed by the study of the oxidative conversion of 3,4-dihydroxyphenylalanine (DOPA) to the non-NMDA receptor agonist and neurotoxin 2,4,5-trihydroxyphenylalanine (TOPA) quinone. Finally, we summarize our work linking oxidative injury to the liberation of zinc from intracellular metal binding proteins, leading to the uncovering of a signaling mechanism connecting excitotoxicity with zinc-activated cell death-signaling cascades.
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Affiliation(s)
- Elias Aizenman
- Department of Neurobiology, Pittsburgh Institute for Neurodegenerative Diseases, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Ralph H. Loring
- Department of Pharmaceutical Sciences, School of Pharmacy, Northeastern University, Boston, MA, United States
| | | | - Paul A. Rosenberg
- Program in Neuroscience, F.M. Kirby Neurobiology Center, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
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5
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How cellular Zn 2+ signaling drives physiological functions. Cell Calcium 2018; 75:53-63. [PMID: 30145429 DOI: 10.1016/j.ceca.2018.08.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 08/16/2018] [Accepted: 08/17/2018] [Indexed: 01/10/2023]
Abstract
Zinc is an essential micronutrient affecting many aspects of human health. Cellular Zn2+ homeostasis is critical for cell function and survival. Zn2+, acting as a first or second messenger, triggers signaling pathways that mediate the physiological roles of Zn2+. Transient changes in Zn2+ concentrations within the cell or in the extracellular region occur following its release from Zn2+ binding metallothioneins, its transport across membranes by the ZnT or ZIP transporters, or release of vesicular Zn2+. These transients activate a distinct Zn2+ sensing receptor, ZnR/GPR39, or modulate numerous proteins and signaling pathways. Importantly, Zn2+ signaling regulates cellular physiological functions such as: proliferation, differentiation, ion transport and secretion. Indeed, novel therapeutic approaches aimed to maintain Zn2+ homeostasis and signaling are evolving. This review focuses on recent findings describing roles of Zn2+ and its transporters in regulating physiological or pathological processes.
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6
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Kang M, Zhao L, Ren M, Deng M, Li C. Reduced metallothionein expression induced by Zinc deficiency results in apoptosis in hepatic stellate cell line LX-2. Int J Clin Exp Med 2015; 8:20603-20609. [PMID: 26884979 PMCID: PMC4723824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 06/04/2015] [Indexed: 06/05/2023]
Abstract
The present study is to investigate the molecular mechanism by which Zinc (Zn) deficiency induces apoptosis in hepatic stellate cells. LX-2 cells were incubated with N,N,N',N'-tetrakis(2-pyridylmethyl)ethane-1,2-diamine (TPEN; 5 μM, 10 μM and 25 μM) for 24 h. MTT assay was used to test the proliferation ability of LX-2 cells. Flow cytometry was performed to detect cell apoptosis. Western blotting assay was employed to determine the expression of metallothionein (MT). Atomic absorption spectroscopy was performed to measure intracellular reactive oxygen species content. To test the activity of mitochondria, respiratory control rate was tested. To investigate the activation of apoptotic signaling pathway, cytochrome C oxidase activity was determined. TPEN effectively decreased the content of Zn in LX-2 cells. Zn deficiency led to the inhibition of proliferation and enhancement of apoptosis of LX-2 cells. Zn deficiency induced the inhibition of MT expression in LX-2 cells. Inhibition of MT expression induced by Zn deficiency resulted in enhanced reactive oxygen species content, impaired mitochondrial function and inhibition of cytochrome C oxidase activity. Intracellular MT content in LX-2 cells is reduced by Zn deficiency. Reduction in MT expression further increases intracellular ROS content, enhances oxidative stress, inhibits cytochrome C oxidase activity, impairs mitochondrial function, and finally leads to cell apoptosis.
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Affiliation(s)
- Min Kang
- Department of Gastroenterology, The Affiliated Hospital of Luzhou Medical CollegeLuzhou City 646000, P.R. China
| | - Lei Zhao
- Department of Gastroenterology, The Second Affiliated Hospital of Harbin Medical UniversityHarbin City 150000, P.R. China
| | - Meiping Ren
- Research Center for Drug and Functional Foods, Luzhou Medical CollegeLuzhou City 646000, P.R. China
| | - Mingming Deng
- Department of Gastroenterology, The Affiliated Hospital of Luzhou Medical CollegeLuzhou City 646000, P.R. China
| | - Changping Li
- Department of Gastroenterology, The Affiliated Hospital of Luzhou Medical CollegeLuzhou City 646000, P.R. China
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Abstract
Cell shrinkage is a hallmark and contributes to signaling of apoptosis. Apoptotic cell shrinkage requires ion transport across the cell membrane involving K(+) channels, Cl(-) or anion channels, Na(+)/H(+) exchange, Na(+),K(+),Cl(-) cotransport, and Na(+)/K(+)ATPase. Activation of K(+) channels fosters K(+) exit with decrease of cytosolic K(+) concentration, activation of anion channels triggers exit of Cl(-), organic osmolytes, and HCO3(-). Cellular loss of K(+) and organic osmolytes as well as cytosolic acidification favor apoptosis. Ca(2+) entry through Ca(2+)-permeable cation channels may result in apoptosis by affecting mitochondrial integrity, stimulating proteinases, inducing cell shrinkage due to activation of Ca(2+)-sensitive K(+) channels, and triggering cell-membrane scrambling. Signaling involved in the modification of cell-volume regulatory ion transport during apoptosis include mitogen-activated kinases p38, JNK, ERK1/2, MEKK1, MKK4, the small G proteins Cdc42, and/or Rac and the transcription factor p53. Osmosensing involves integrin receptors, focal adhesion kinases, and tyrosine kinase receptors. Hyperosmotic shock leads to vesicular acidification followed by activation of acid sphingomyelinase, ceramide formation, release of reactive oxygen species, activation of the tyrosine kinase Yes with subsequent stimulation of CD95 trafficking to the cell membrane. Apoptosis is counteracted by mechanisms involved in regulatory volume increase (RVI), by organic osmolytes, by focal adhesion kinase, and by heat-shock proteins. Clearly, our knowledge on the interplay between cell-volume regulatory mechanisms and suicidal cell death is still far from complete and substantial additional experimental effort is needed to elucidate the role of cell-volume regulatory mechanisms in suicidal cell death.
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Affiliation(s)
- Florian Lang
- Institute of Physiology, University of Tübingen, Tübingen, Germany
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Kaur G, Pandey O, Singh K, Homa D, Scott B, Pickrell G. A review of bioactive glasses: Their structure, properties, fabrication and apatite formation. J Biomed Mater Res A 2013; 102:254-74. [DOI: 10.1002/jbm.a.34690] [Citation(s) in RCA: 358] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 02/14/2013] [Accepted: 02/20/2013] [Indexed: 01/13/2023]
Affiliation(s)
- Gurbinder Kaur
- Department of Material Science and Engineering; Holden Hall, Virginia Tech; Blacksburg-24060 Virginia USA
| | - O.P. Pandey
- School of Physics and Materials Science; Thapar University; Patiala-147004, Punjab India
| | - K. Singh
- School of Physics and Materials Science; Thapar University; Patiala-147004, Punjab India
| | - Dan Homa
- Department of Material Science and Engineering; Holden Hall, Virginia Tech; Blacksburg-24060 Virginia USA
| | - Brian Scott
- Department of Material Science and Engineering; Holden Hall, Virginia Tech; Blacksburg-24060 Virginia USA
| | - Gary Pickrell
- Department of Material Science and Engineering; Holden Hall, Virginia Tech; Blacksburg-24060 Virginia USA
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Neuroprotective effects of Cyperus rotundus on SIN-1 induced nitric oxide generation and protein nitration: ameliorative effect against apoptosis mediated neuronal cell damage. Neurotoxicology 2012; 34:150-9. [PMID: 23174672 DOI: 10.1016/j.neuro.2012.11.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 11/09/2012] [Accepted: 11/09/2012] [Indexed: 11/21/2022]
Abstract
Nitrosylation of tyrosine (3-nitro tyrosine, 3-NT) has been implicated in the pathophysiology of various disorders particularly neurodegenerative conditions and aging. Cyperus rotundus rhizome is being used as a traditional folk medicine to alleviate a variety of disorders including neuronal stress. The herb has recently found applications in food and confectionary industries also. In current study, we have explored the protective effects of C. rotundus rhizome extract (CRE) through its oxido-nitrosative and anti apoptotic mechanism to attenuate peroxynitrite (ONOO(-)) induced neurotoxicity using human neuroblastoma SH-SY5Y cells. Our results elucidate that pre-treatment of neurons with CRE ameliorates the mitochondrial and plasma membrane damage induced by 500 μM SIN-1 to 80% and 24% as evidenced by MTT and LDH assays. CRE inhibited NO generation by downregulating i-NOS expression. SIN-1 induced depletion of antioxidant enzyme status was also replenished by CRE which was confirmed by immunoblot analysis of SOD and CAT. The CRE pre-treatment efficiently potentiated the SIN-1 induced apoptotic biomarkers such as bcl-2 and caspase-3 which orchestrate the proteolytic damage of the cell. The ONOO(-) induced damage to cellular, nuclear and mitochondrial integrity was also restored by CRE. Furthermore, CRE pre-treatment also regulated the 3-NT formation which shows the potential of plant extract against tyrosine nitration. Taken together, our findings suggest that CRE might be developed as a preventive agent against ONOO(-) induced apoptosis.
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Zinc sensing receptor signaling, mediated by GPR39, reduces butyrate-induced cell death in HT29 colonocytes via upregulation of clusterin. PLoS One 2012; 7:e35482. [PMID: 22545109 PMCID: PMC3335870 DOI: 10.1371/journal.pone.0035482] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 03/16/2012] [Indexed: 02/06/2023] Open
Abstract
Zinc enhances epithelial proliferation, protects the digestive epithelial layer and has profound antiulcerative and antidiarrheal roles in the colon. Despite the clinical significance of this ion, the mechanisms linking zinc to these cellular processes are poorly understood. We have previously identified an extracellular Zn2+ sensing G-protein coupled receptor (ZnR) that activates Ca2+ signaling in colonocytes, but its molecular identity as well as its effects on colonocytes' survival remained elusive. Here, we show that Zn2+, by activation of the ZnR, protects HT29 colonocytes from butyrate induced cell death. Silencing of the G-protein coupled receptor GPR39 expression abolished ZnR-dependent Ca2+ release and Zn2+-dependent survival of butyrate-treated colonocytes. Importantly, GPR39 also mediated ZnR-dependent upregulation of Na+/H+ exchange activity as this activity was found in native colon tissue but not in tissue obtained from GPR39 knock-out mice. Although ZnR-dependent upregulation of Na+/H+ exchange reduced the cellular acid load induced by butyrate, it did not rescue HT29 cells from butyrate induced cell death. ZnR/GPR39 activation however, increased the expression of the anti-apoptotic protein clusterin in butyrate-treated cells. Furthermore, silencing of clusterin abolished the Zn2+-dependent survival of HT29 cells. Altogether, our results demonstrate that extracellular Zn2+, acting through ZnR, regulates intracellular pH and clusterin expression thereby enhancing survival of HT29 colonocytes. Moreover, we identify GPR39 as the molecular moiety of ZnR in HT29 and native colonocytes.
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Abstract
Our understanding of the roles played by zinc in the physiological and pathological functioning of the brain is rapidly expanding. The increased availability of genetically modified animal models, selective zinc-sensitive fluorescent probes, and novel chelators is producing a remarkable body of exciting new data that clearly establishes this metal ion as a key modulator of intracellular and intercellular neuronal signaling. In this Mini-Symposium, we will review and discuss the most recent findings that link zinc to synaptic function as well as the injurious effects of zinc dyshomeostasis within the context of neuronal death associated with major human neurological disorders, including stroke, epilepsy, and Alzheimer's disease.
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Fukada T, Yamasaki S, Nishida K, Murakami M, Hirano T. Zinc homeostasis and signaling in health and diseases: Zinc signaling. J Biol Inorg Chem 2011; 16:1123-34. [PMID: 21660546 PMCID: PMC3176402 DOI: 10.1007/s00775-011-0797-4] [Citation(s) in RCA: 390] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 05/09/2011] [Indexed: 11/26/2022]
Abstract
The essential trace element zinc (Zn) is widely required in cellular functions, and abnormal Zn homeostasis causes a variety of health problems that include growth retardation, immunodeficiency, hypogonadism, and neuronal and sensory dysfunctions. Zn homeostasis is regulated through Zn transporters, permeable channels, and metallothioneins. Recent studies highlight Zn's dynamic activity and its role as a signaling mediator. Zn acts as an intracellular signaling molecule, capable of communicating between cells, converting extracellular stimuli to intracellular signals, and controlling intracellular events. We have proposed that intracellular Zn signaling falls into two classes, early and late Zn signaling. This review addresses recent findings regarding Zn signaling and its role in physiological processes and pathogenesis.
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Affiliation(s)
- Toshiyuki Fukada
- Laboratory for Cytokine Signaling, RIKEN Research Center for Allergy and Immunology, Yokohama, Kanagawa 230-0045 Japan
- Laboratory of Allergy and Immunology, Graduate School of Medicine, Osaka University, Osaka, 565-0871 Japan
| | - Satoru Yamasaki
- Laboratory for Cytokine Signaling, RIKEN Research Center for Allergy and Immunology, Yokohama, Kanagawa 230-0045 Japan
| | - Keigo Nishida
- Laboratory for Cytokine Signaling, RIKEN Research Center for Allergy and Immunology, Yokohama, Kanagawa 230-0045 Japan
- Immune System, Cooperation Program, Graduate School of Frontier Biosciences, Osaka University, Osaka, 565-0871 Japan
| | - Masaaki Murakami
- Laboratories of Developmental Immunology, JST-CREST, Graduate School of Frontier Biosciences, Graduate School of Medicine, WPI Immunology Frontier Research Center, Osaka University, Osaka, 565-0871 Japan
| | - Toshio Hirano
- Laboratory for Cytokine Signaling, RIKEN Research Center for Allergy and Immunology, Yokohama, Kanagawa 230-0045 Japan
- Laboratories of Developmental Immunology, JST-CREST, Graduate School of Frontier Biosciences, Graduate School of Medicine, WPI Immunology Frontier Research Center, Osaka University, Osaka, 565-0871 Japan
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Lang F, Ullrich S, Gulbins E. Ceramide formation as a target in beta-cell survival and function. Expert Opin Ther Targets 2011; 15:1061-71. [PMID: 21635197 DOI: 10.1517/14728222.2011.588209] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Ceramide may be synthesized de novo or generated by sphingomyelinase-dependent hydrolysis of sphingomyelin. AREAS COVERED The role of ceramide, ceramide-sensitive signaling and ion channels in β-cell apoptosis, lipotoxicity and amyloid-induced β-cell death. EXPERT OPINION Ceramide participates in β-cell dysfunction and apoptosis after exposure to TNFα, IL-1β and IFN-γ, excessive amyloid and islet amyloid polypeptide or non-esterified fatty acids (lipotoxicity). Knockout of sphingomyelin synthase 1, which converts ceramide to sphingomyelin, leads to impairment of insulin secretion. Increased ceramidase activity or pharmacological inhibition of ceramide synthetase, inhibits β-cell apoptosis. Ceramide contributes to endoplasmatic reticulum (ER) stress, decreased mitochondrial membrane potential in insulin-secreting cells and mitochondrial release of cytochrome c into the cytosol, which are all triggers of apoptotic cell death. Ceramide-dependent signaling involves activation of extracellularly regulated kinases 1 and 2 (ERK1/2), downregulation of Period (Per)-aryl hydrocarbon receptor nuclear translocator (Arnt)-single-minded (Sim) kinase (PASK), activation of okadaic-acid-sensitive protein phosphatase 2A (PP2A) and stimulation of NADPH-oxidase with generation of superoxides and lipid peroxides. Ceramide reduces the activity of voltage gated potassium (Kv)-channels in insulin-secreting cells. The role of ceramide in β-cell survival and function may be therapeutically relevant, because ceramide formation can be suppressed by pharmacological inhibition of ceramide synthetase and/or sphingomyelinase.
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Affiliation(s)
- Florian Lang
- University of Tübingen, Institute of Physiology, Germany.
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14
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Aizenman E, McCord MC, Saadi RA, Hartnett KA, He K. Complex role of zinc in methamphetamine toxicity in vitro. Neuroscience 2010; 171:31-9. [PMID: 20801194 PMCID: PMC2956874 DOI: 10.1016/j.neuroscience.2010.08.049] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 08/19/2010] [Accepted: 08/22/2010] [Indexed: 11/21/2022]
Abstract
Methamphetamine is a drug of abuse that can induce oxidative stress and neurotoxicity to dopaminergic neurons. We have previously reported that oxidative stress promotes the liberation of intracellular Zn(2+) from metal-binding proteins, which, in turn, can initiate neuronal injurious signaling processes. Here, we report that methamphetamine mobilizes Zn(2+) in catecholaminergic rat pheochromocytoma (PC12) cells, as measured by an increase in Zn(2+)-regulated gene expression driven by the metal response element transcription factor-1. Moreover, methamphetamine-liberated Zn(2+) was responsible for a pronounced enhancement in voltage-dependent K(+) currents in these cells, a process that normally accompanies Zn(2+)-dependent cell injury. Overnight exposure to methamphetamine induced PC12 cell death. This toxicity could be prevented by the cell-permeant zinc chelator N,N,N', N'-tetrakis(2-pyridylmethyl)-ethylenediamine (TPEN), and by over-expression of the Zn(2+)-binding protein metallothionein 3 (MT3), but not by tricine, an extracellular Zn(2+) chelator. The toxicity of methamphetamine to PC12 cells was enhanced by the presence of co-cultured microglia. Remarkably, under these conditions, TPEN no longer protected but, in fact, dramatically exacerbated methamphetamine toxicity, tricine again being without effect. Over-expression of MT3 in PC12 cells did not mimic these toxicity-enhancing actions of TPEN, suggesting that the chelator affected microglial function. Interestingly, P2X receptor antagonists reversed the toxicity-enhancing effect of TPEN. As such, endogenous levels of intracellular Zn(2+) may normally interfere with the activation of P2X channels in microglia. We conclude that Zn(2+) plays a significant but complex role in modulating the cellular response of PC12 cells to methamphetamine exposure in both the absence and presence of microglia.
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Affiliation(s)
- E Aizenman
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
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15
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Sheline CT, Cai AL, Zhu J, Shi C. Serum or target deprivation-induced neuronal death causes oxidative neuronal accumulation of Zn2+ and loss of NAD+. Eur J Neurosci 2010; 32:894-904. [PMID: 20722716 DOI: 10.1111/j.1460-9568.2010.07372.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Trophic deprivation-mediated neuronal death is important during development, after acute brain or nerve trauma, and in neurodegeneration. Serum deprivation (SD) approximates trophic deprivation in vitro, and an in vivo model is provided by neuronal death in the mouse dorsal lateral geniculate nucleus (LGNd) after ablation of the visual cortex (VCA). Oxidant-induced intracellular Zn(2+) release ([Zn(2+) ](i) ) from metallothionein-3 (MT-III), mitochondria or 'protein Zn(2+) ', was implicated in trophic deprivation neurotoxicity. We have previously shown that neurotoxicity of extracellular Zn(2+) required entry, increased [Zn(2+) ](i) , and reduction of NAD(+) and ATP levels causing inhibition of glycolysis and cellular metabolism. Exogenous NAD(+) and sirtuin inhibition attenuated Zn(2+) neurotoxicity. Here we show that: (1) Zn(2+) is released intracellularly after oxidant and SD injuries, and that sensitivity to these injuries is proportional to neuronal Zn(2+) content; (2) NAD(+) loss is involved - restoration of NAD(+) using exogenous NAD(+) , pyruvate or nicotinamide attenuated these injuries, and potentiation of NAD(+) loss potentiated injury; (3) neurons from genetically modified mouse strains which reduce intracellular Zn(2+) content (MT-III knockout), reduce NAD(+) catabolism (PARP-1 knockout) or increase expression of an NAD(+) synthetic enzyme (Wld(s) ) each had attenuated SD and oxidant neurotoxicities; (4) sirtuin inhibitors attenuated and sirtuin activators potentiated these neurotoxicities; (5) visual cortex ablation (VCA) induces Zn(2+) staining and death only in ipsilateral LGNd neurons, and a 1 mg/kg Zn(2+) diet attenuated injury; and finally (6) NAD(+) synthesis and levels are involved given that LGNd neuronal death after VCA was dramatically reduced in Wld(s) animals, and by intraperitoneal pyruvate or nicotinamide. Zn(2+) toxicity is involved in serum and trophic deprivation-induced neuronal death.
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Affiliation(s)
- Christian T Sheline
- Department of Ophthalmology and the Neuroscience Center of Excellence, LSU Health Sciences Center, 2020 Gravier Street, Suite D, New Orleans, LA 70112, USA.
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16
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Railey AM, Micheli TL, Wanschura PB, Flinn JM. Alterations in fear response and spatial memory in pre- and post-natal zinc supplemented rats: remediation by copper. Physiol Behav 2010; 100:95-100. [PMID: 20159028 DOI: 10.1016/j.physbeh.2010.01.040] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2009] [Revised: 01/26/2010] [Accepted: 01/29/2010] [Indexed: 01/25/2023]
Abstract
The role of zinc in the nervous system is receiving increased attention. At a time when dietary fortification and supplementation have increased the amount of zinc being consumed, little work has been done on the effects of enhanced zinc on behavior. Both zinc and copper are essential trace minerals that are acquired from the diet; under normal conditions the body protects against zinc overload, but at excessive dosages, copper deficiency has been seen. In order to examine the effect of enhanced metal administration on learning and memory, Sprague Dawley rats were given water supplemented with 10ppm Zn, 10ppm Zn+0.25ppm Cu, or normal lab water, during pre- and post-natal development. Fear conditioning tests at 4months showed significantly higher freezing rates during contextual retention and extinction and cued extinction for rats drinking water supplemented with zinc, suggesting increased anxiety compared to controls raised on lab water. During the MWM task at 9months, zinc-enhanced rats had significantly longer latencies to reach the platform compared to controls. The addition of copper to the zinc supplemented water brought freezing and latency levels closer to that of controls. These data demonstrate the importance of maintaining appropriate intake of both metals simultaneously, and show that long-term supplementation with zinc may cause alterations in memory.
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Affiliation(s)
- Angela M Railey
- George Mason University, Psychology Department, 4400 University Drive, Fairfax, VA 22030, United States
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17
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Sphingomyelinase dependent apoptosis following treatment of pancreatic beta-cells with amyloid peptides Aß1-42 or IAPP. Apoptosis 2009; 14:878-89. [DOI: 10.1007/s10495-009-0364-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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18
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A comparison of Zn2+- and Ca2+-triggered depolarization of liver mitochondria reveals no evidence of Zn2+-induced permeability transition. Cell Calcium 2009; 45:447-55. [PMID: 19349076 DOI: 10.1016/j.ceca.2009.03.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Revised: 02/28/2009] [Accepted: 03/03/2009] [Indexed: 01/27/2023]
Abstract
Intracellular Zn(2+) toxicity is associated with mitochondrial dysfunction. Zn(2+) depolarizes mitochondria in assays using isolated organelles as well as cultured cells. Some reports suggest that Zn(2+)-induced depolarization results from the opening of the mitochondrial permeability transition pore (mPTP). For a more detailed analysis of this relationship, we compared Zn(2+)-induced depolarization with the effects of Ca(2+) in single isolated rat liver mitochondria monitored with the potentiometric probe rhodamine 123. Consistent with previous work, we found that relatively low levels of Ca(2+) caused rapid, complete and irreversible loss of mitochondrial membrane potential, an effect that was diminished by classic inhibitors of mPT, including high Mg(2+), ADP and cyclosporine A. Zn(2+) also depolarized mitochondria, but only at relatively high concentrations. Furthermore Zn(2+)-induced depolarization was slower, partial and sometimes reversible, and was not affected by inhibitors of mPT. We also compared the effects of Ca(2+) and Zn(2+) in a calcein-retention assay. Consistent with the well-documented ability of Ca(2+) to induce mPT, we found that it caused rapid and substantial loss of matrix calcein. In contrast, calcein remained in Zn(2+)-treated mitochondria. Considered together, our results suggest that Ca(2+) and Zn(2+) depolarize mitochondria by considerably different mechanisms, that opening of the mPTP is not a direct consequence of Zn(2+)-induced depolarization, and that Zn(2+) is not a particularly potent mitochondrial inhibitor.
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19
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Shi L, Song N, Jiang H, Wang J, Ma Z, Xie J. Potassium channels are involved in zinc-induced apoptosis in MES23.5 cells. J Neurosci Res 2009; 87:514-21. [DOI: 10.1002/jnr.21854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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20
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Rotenone inhibits delayed rectifier K+ current via a protein kinase A-dependent mechanism. Neuroreport 2008; 19:1401-5. [DOI: 10.1097/wnr.0b013e32830d149e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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21
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Starodubtseva MN, Tattersall AL, Kuznetsova TG, Yegorenkov NI, Ellory JC. Structural and functional changes in the membrane and membrane skeleton of red blood cells induced by peroxynitrite. Bioelectrochemistry 2008; 73:155-62. [DOI: 10.1016/j.bioelechem.2008.01.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2007] [Revised: 12/16/2007] [Accepted: 01/17/2008] [Indexed: 12/15/2022]
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22
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Ho Y, Samarasinghe R, Knoch ME, Lewis M, Aizenman E, DeFranco DB. Selective inhibition of mitogen-activated protein kinase phosphatases by zinc accounts for extracellular signal-regulated kinase 1/2-dependent oxidative neuronal cell death. Mol Pharmacol 2008; 74:1141-51. [PMID: 18635668 DOI: 10.1124/mol.108.049064] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Oxidative stress induced by glutathione depletion in the mouse HT22 neuroblastoma cell line and embryonic rat immature cortical neurons causes a delayed, sustained activation of extracellular signal-regulated kinase (ERK) 1/2, which is required for cell death. This sustained activation of ERK1/2 is mediated primarily by a selective inhibition of distinct ERK1/2-directed phosphatases either by enhanced degradation (i.e., for mitogen-activated protein kinase phosphatase-1) or as shown here by reductions in enzymatic activity (i.e., for protein phosphatase type 2A). The inhibition of ERK1/2 phosphatases in HT22 cells and immature neurons subjected to glutathione depletion results from oxidative stress because phosphatase activity is restored in cells treated with the antioxidant butylated hydroxyanisole. This leads to reduced ERK1/2 activation and neuroprotection. Furthermore, an increase in free intracellular zinc that accompanies glutathione-induced oxidative stress in HT22 cells and immature neurons contributes to selective inhibition of ERK1/2 phosphatase activity and cell death. Finally, ERK1/2 also functions to maintain elevated levels of zinc. Thus, the elevation of intracellular zinc within neurons subjected to oxidative stress can trigger a robust positive feedback loop operating through activated ERK1/2 that rapidly sets into motion a zinc-dependent pathway of cell death.
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Affiliation(s)
- Yeung Ho
- Department of Neuroscience, University of Pittsburgh School of Medicine, 7041 BST 3, 3501 Fifth Ave., Pittsburgh, PA 15261, USA
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23
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Knoch ME, Hartnett KA, Hara H, Kandler K, Aizenman E. Microglia induce neurotoxicity via intraneuronal Zn(2+) release and a K(+) current surge. Glia 2008; 56:89-96. [PMID: 17955552 DOI: 10.1002/glia.20592] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Microglial cells are critical components of the injurious cascade in a large number of neurodegenerative diseases. However, the precise molecular mechanisms by which microglia mediate neuronal cell death have not been fully delineated. We report here that reactive species released from activated microglia induce the liberation of Zn(2+) from intracellular stores in cultured cortical neurons, with a subsequent enhancement in neuronal voltage-gated K(+) currents, two events that have been intimately linked to apoptosis. Both the intraneuronal Zn(2+) release and the K(+) current surge could be prevented by the NADPH oxidase inhibitor apocynin, the free radical scavenging mixture of superoxide dismutase and catalase, as well as by 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrinato iron(III) chloride. The enhancement of K(+) currents was prevented by neuronal overexpression of metallothionein III or by expression of a dominant negative (DN) vector for the upstream mitogen-activated protein kinase apoptosis signal regulating kinase-1 (ASK-1). Importantly, neurons overexpressing metallothionein-III or transfected with DN vectors for ASK-1 or Kv2.1-encoded K(+) channels were resistant to microglial-induced toxicity. These results establish a direct link between microglial-generated oxygen and nitrogen reactive products and neuronal cell death mediated by intracellular Zn(2+) release and a surge in K(+) currents.
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Affiliation(s)
- Megan E Knoch
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA
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24
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Lang F, Gulbins E, Szabo I, Vereninov A, Huber SM. Ion Channels, Cell Volume, Cell Proliferation and Apoptotic Cell Death. SENSING WITH ION CHANNELS 2008. [DOI: 10.1007/978-3-540-72739-2_4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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25
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Sekler I, Sensi SL, Hershfinkel M, Silverman WF. Mechanism and regulation of cellular zinc transport. Mol Med 2007. [PMID: 17622322 DOI: 10.2119/2007-00037.sekler] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Zinc is an essential cofactor for the activity and folding of up to ten percent of mammalian proteins and can modulate the function of many others. Because of the pleiotropic effects of zinc on every aspect of cell physiology, deficits of cellular zinc content, resulting from zinc deficiency or excessive rise in its cellular concentration, can have catastrophic consequences and are linked to major patho-physiologies including diabetes and stroke. Thus, the concentration of cellular zinc requires establishment of discrete, active cellular gradients. The cellular distribution of zinc into organelles is precisely managed to provide the zinc concentration required by each cell compartment. The complexity of zinc homeostasis is reflected by the surprisingly large variety and number of zinc homeostatic proteins found in virtually every cell compartment. Given their ubiquity and importance, it is surprising that many aspects of the function, regulation, and crosstalk by which zinc transporters operate are poorly understood. In this mini-review, we will focus on the mechanisms and players required for generating physiologically appropriate zinc gradients across the plasma membrane and vesicular compartments. We will also highlight some of the unsolved issues regarding their role in cellular zinc homeostasis.
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Affiliation(s)
- Israel Sekler
- Department of Physiology, Faculty of Health Science, and The Zlotowski Center for Neuroscience, Ben Gurion University of the Negev, POB 653, Beer-Sheva, Israel.
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26
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Zhang Y, Aizenman E, DeFranco DB, Rosenberg PA. Intracellular zinc release, 12-lipoxygenase activation and MAPK dependent neuronal and oligodendroglial death. Mol Med 2007. [PMID: 17622306 DOI: 10.2119/2007-00042.zhang] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Zinc translocation from presynaptic nerve terminals to postsynaptic neurons has generally been considered the critical step leading to the accumulation of intracellular free zinc and subsequent neuronal injury. Recent evidence, however, strongly suggests that the liberation of zinc from intracellular stores upon oxidative and nitrative stimulation contributes significantly to the toxicity of this metal not only to neurons, but also to oligodendrocytes. The exact cell death signaling pathways triggered by zinc are beginning to be deciphered. In this review, we describe how the activation of 12-lipoxygenase and mitogen-activated protein kinase (MAPK) contribute to the toxicity of liberated zinc to neurons and oligodendrocytes.
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Affiliation(s)
- Yumin Zhang
- Department of Anatomy, Physiology and Genetics and Program in Neuroscience, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA.
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27
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Föller M, Mahmud H, Koka S, Lang F. Reduced Ca2+ entry and suicidal death of erythrocytes in PDK1 hypomorphic mice. Pflugers Arch 2007; 455:939-49. [PMID: 17899170 DOI: 10.1007/s00424-007-0336-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 08/07/2007] [Accepted: 08/23/2007] [Indexed: 12/16/2022]
Abstract
The phosphoinositide-dependent kinase PDK1 is a key element in the phosphoinositol-3-kinase signalling pathway, which is involved in the regulation of ion channels, transporters, cell volume and cell survival. Eryptosis, the suicidal death of erythrocytes, is characterized by decrease in cell volume, cell membrane blebbing and phospholipids scrambling with phosphatidylserine exposure at the cell surface. Oxidative stress, osmotic shock or Cl- removal trigger eryptosis by activation of Ca2+-permeable cation channels and subsequent increase in cytosolic Ca2+ activity. To explore the impact of PDK1 for erythrocyte survival, eryptosis was analysed in hypomorphic mice (pdk1hm) expressing only some 25% of PDK1 and in their wild-type littermates (pdk1wt). Cell volume was estimated from forward scatter and phosphatidylserine exposure from annexin-V binding in fluorescence activated cell sorter analysis. Forward scatter was smaller in pdk1hm than in pdk1wt erythrocytes. Oxidative stress (100 microM tert-butylhydroperoxide), osmotic shock (+300 mM sucrose) and Cl- removal (replacement of Cl- with gluconate) all decreased forward scatter and increased the percentage of annexin-V-binding erythrocytes from both pdk1hm and pdk1wt mice. After treatment, the forward scatter was similar in both genotypes, but the percentage of annexin-V binding was significantly smaller in pdk1hm than in pdk1wt erythrocytes. According to Fluo-3 fluorescence, cytosolic Ca2+ activity was significantly smaller in pdk1hm than in pdk1wt erythrocytes. Treatment with Ca2+-ionophore ionomycin (1 microM) was followed by an increase in annexin-V binding to similar levels in pdk1hm and pdk1wt erythrocytes. The experiments reveal that PDK1 deficiency is associated with decreased Ca2+ entry into erythrocytes and thus with blunted eryptotic effects of oxidative stress, osmotic shock and Cl- removal.
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Affiliation(s)
- Michael Föller
- Department of Physiology, University of Tuebingen, Gmelinstr. 5, 72076 Tübingen, Germany
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28
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Zhang Y, Aizenman E, DeFranco DB, Rosenberg PA. Intracellular zinc release, 12-lipoxygenase activation and MAPK dependent neuronal and oligodendroglial death. MOLECULAR MEDICINE (CAMBRIDGE, MASS.) 2007; 13:350-5. [PMID: 17622306 PMCID: PMC1952666 DOI: 10.2119/2007–00042.zhang] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Accepted: 06/12/2007] [Indexed: 11/06/2022]
Abstract
Zinc translocation from presynaptic nerve terminals to postsynaptic neurons has generally been considered the critical step leading to the accumulation of intracellular free zinc and subsequent neuronal injury. Recent evidence, however, strongly suggests that the liberation of zinc from intracellular stores upon oxidative and nitrative stimulation contributes significantly to the toxicity of this metal not only to neurons, but also to oligodendrocytes. The exact cell death signaling pathways triggered by zinc are beginning to be deciphered. In this review, we describe how the activation of 12-lipoxygenase and mitogen-activated protein kinase (MAPK) contribute to the toxicity of liberated zinc to neurons and oligodendrocytes.
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Affiliation(s)
- Yumin Zhang
- Department of Anatomy, Physiology and Genetics and Program in Neuroscience, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA.
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29
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Sekler I, Sensi SL, Hershfinkel M, Silverman WF. Mechanism and regulation of cellular zinc transport. MOLECULAR MEDICINE (CAMBRIDGE, MASS.) 2007; 13:337-43. [PMID: 17622322 PMCID: PMC1952664 DOI: 10.2119/2007–00037.sekler] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Accepted: 05/30/2007] [Indexed: 11/06/2022]
Abstract
Zinc is an essential cofactor for the activity and folding of up to ten percent of mammalian proteins and can modulate the function of many others. Because of the pleiotropic effects of zinc on every aspect of cell physiology, deficits of cellular zinc content, resulting from zinc deficiency or excessive rise in its cellular concentration, can have catastrophic consequences and are linked to major patho-physiologies including diabetes and stroke. Thus, the concentration of cellular zinc requires establishment of discrete, active cellular gradients. The cellular distribution of zinc into organelles is precisely managed to provide the zinc concentration required by each cell compartment. The complexity of zinc homeostasis is reflected by the surprisingly large variety and number of zinc homeostatic proteins found in virtually every cell compartment. Given their ubiquity and importance, it is surprising that many aspects of the function, regulation, and crosstalk by which zinc transporters operate are poorly understood. In this mini-review, we will focus on the mechanisms and players required for generating physiologically appropriate zinc gradients across the plasma membrane and vesicular compartments. We will also highlight some of the unsolved issues regarding their role in cellular zinc homeostasis.
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Affiliation(s)
- Israel Sekler
- Department of Physiology, Faculty of Health Science, and The Zlotowski Center for Neuroscience, Ben Gurion University of the Negev, POB 653, Beer-Sheva, Israel.
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30
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Stamoulis I, Kouraklis G, Theocharis S. Zinc and the liver: an active interaction. Dig Dis Sci 2007; 52:1595-612. [PMID: 17415640 DOI: 10.1007/s10620-006-9462-0] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2006] [Accepted: 05/19/2006] [Indexed: 02/06/2023]
Abstract
Zinc is an essential trace element, exerting important antioxidant, anti-inflammatory, and antiapoptotic effects. It affects growth and development and participates in processes such as aging and cancer induction. The liver is important for the regulation of zinc homeostasis, while zinc is necessary for proper liver function. Decreased zinc levels have been implicated in both acute and chronic liver disease states, and zinc deficiency has been implicated in the pathogenesis of liver diseases. Zinc supplementation offers protection in experimental animal models of acute and chronic liver injury, but these hepatoprotective properties have not been fully elucidated. In the present review, data on zinc homeostasis, its implication in the pathogenesis of liver diseases, and its effect on acute and chronic liver diseases are presented. It is concluded that zinc could protect against liver diseases, although up to now the underlying pathophysiology of zinc and liver interactions have not been defined.
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Affiliation(s)
- Ioannis Stamoulis
- Department of Forensic Medicine and Toxicology, University of Athens, Medical School, Goudi, Athens, Greece
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31
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Föller M, Kasinathan RS, Koka S, Huber SM, Schuler B, Vogel J, Gassmann M, Lang F. Enhanced susceptibility to suicidal death of erythrocytes from transgenic mice overexpressing erythropoietin. Am J Physiol Regul Integr Comp Physiol 2007; 293:R1127-34. [PMID: 17567717 DOI: 10.1152/ajpregu.00110.2007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Eryptosis, a suicidal death of mature erythrocytes, is characterized by decrease of cell volume, cell membrane blebbing, and breakdown of cell membrane asymmetry with phosphatidylserine exposure at the cell surface. Triggers of eryptosis include increased cytosolic Ca(2+) activity, which could result from activation of Ca(2+)-permeable cation channels. Ca(2+) triggers phosphatidylserine exposure and activates Ca(2+)-sensitive K(+) channels, leading to cellular K(+) loss and cell shrinkage. The cation channels and thus eryptosis are stimulated by Cl(-) removal and inhibited by erythropoietin. The present experiments explored eryptosis in transgenic mice overexpressing erythropoietin (tg6). Erythrocytes were drawn from tg6 mice and their wild-type littermates (WT). Phosphatidylserine exposure was estimated from annexin binding and cell volume from forward scatter in fluorescence-activated cell sorting (FACS) analysis. The percentage of annexin binding was significantly larger and forward scatter significantly smaller in tg6 than in WT erythrocytes. Transgenic erythrocytes were significantly more resistant to osmotic lysis than WT erythrocytes. Cl(-) removal and exposure to the Ca(2+) ionophore ionomycin (1 microM) increased annexin binding and decreased forward scatter, effects larger in tg6 than in WT erythrocytes. The K(+) ionophore valinomycin (10 nM) triggered eryptosis in both tg6 and WT erythrocytes and abrogated differences between genotypes. An increase of extracellular K(+) concentration to 125 mM blunted the difference between tg6 and WT erythrocytes. Fluo-3 fluorescence reflecting cytosolic Ca(2+) activity was larger in tg6 than in WT erythrocytes. In conclusion, circulating erythrocytes from tg6 mice are sensitized to triggers of eryptosis but more resistant to osmotic lysis, properties at least partially due to enhanced Ca(2+) entry and increased K(+) channel activity.
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Affiliation(s)
- Michael Föller
- Physiologisches Institut, der Universität Tübingen, Gmelinstrasse 5, D 72076 Tübingen, Germany
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32
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Aina V, Perardi A, Bergandi L, Malavasi G, Menabue L, Morterra C, Ghigo D. Cytotoxicity of zinc-containing bioactive glasses in contact with human osteoblasts. Chem Biol Interact 2007; 167:207-18. [PMID: 17399695 DOI: 10.1016/j.cbi.2007.03.002] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2006] [Revised: 02/27/2007] [Accepted: 03/01/2007] [Indexed: 01/08/2023]
Abstract
Bioactive glasses such as Hench's 45S5 have applications to tissue engineering and bone repair: the insertion of zinc has been proposed to improve their bone-bonding ability and to slacken their dissolution in extracellular body fluids. In view of a potential clinical application, we have investigated whether zinc-containing 45S5 (HZ) glasses might be cytotoxic for human MG-63 osteoblasts. In our experimental conditions, after 24h of incubation HZ glasses released significant amounts of Zn(2+) and induced in MG-63 cells release of lactate dehydrogenase (index of cytotoxicity) and the following indexes of oxidative stress: (i) accumulation of intracellular malonyldialdehyde, (ii) increased activity of pentose phosphate pathway, (iii) increased expression of heme oxygenase-1, (iv) increased activity of Cu,Zn-superoxide dismutase, (v) decreased level of intracellular thiols. These effects were inversely related to the zinc content of glass powders, were mimicked by ZnCl(2) solutions and were prevented by either metal chelators (EDTA, NTA) or the antioxidant ascorbate, suggesting that Zn(2+) released fastly from HZ glasses can cause MG-63 cell damage via an oxidative stress. This work highlights the importance of designing Zn-containing bioactive glasses without cytotoxic effects and gives supplementary information about the prooxidant role of zinc in living systems.
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Affiliation(s)
- Valentina Aina
- Department of Chemistry IFM and Centre of Excellence NIS, University of Torino, Via Giuria 7, 10125 Torino, Italy
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33
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Redman PT, He K, Hartnett KA, Jefferson BS, Hu L, Rosenberg PA, Levitan ES, Aizenman E. Apoptotic surge of potassium currents is mediated by p38 phosphorylation of Kv2.1. Proc Natl Acad Sci U S A 2007; 104:3568-73. [PMID: 17360683 PMCID: PMC1805571 DOI: 10.1073/pnas.0610159104] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Kv2.1, the primary delayed rectifying potassium channel in neurons, is extensively regulated by phosphorylation. Previous reports have described Kv2.1 phosphorylation events affecting channel gating and the impact of this process on cellular excitability. Kv2.1, however, also provides the critical exit route for potassium ions during neuronal apoptosis via p38 MAPK-dependent membrane insertion, resulting in a pronounced enhancement of K(+) currents. Here, electrophysiological and viability studies using Kv2.1 channel mutants identify a p38 phosphorylation site at Ser-800 (S800) that is required for Kv2.1 membrane insertion, K(+) current surge, and cell death. In addition, a phospho-specific antibody for S800 detects a p38-dependent increase in Kv2.1 phosphorylation in apoptotic neurons and reveals phosphorylation of S800 in immunopurified channels incubated with active p38. Consequently, phosphorylation of Kv2.1 residue S800 by p38 leads to trafficking and membrane insertion during apoptosis, and remarkably, the absence of S800 phosphorylation is sufficient to prevent completion of the cell death program.
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Affiliation(s)
| | - Kai He
- Departments of *Neurobiology and
| | | | | | - Linda Hu
- Department of Neurology and Program in Neuroscience, Children's Hospital and Harvard Medical School, Boston, MA 02115
| | - Paul A. Rosenberg
- Department of Neurology and Program in Neuroscience, Children's Hospital and Harvard Medical School, Boston, MA 02115
| | - Edwin S. Levitan
- Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261; and
| | - Elias Aizenman
- Departments of *Neurobiology and
- To whom correspondence should be addressed. E-mail:
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34
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Lang F, Huber SM, Szabo I, Gulbins E. Plasma membrane ion channels in suicidal cell death. Arch Biochem Biophys 2007; 462:189-94. [PMID: 17316548 DOI: 10.1016/j.abb.2006.12.028] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Revised: 12/21/2006] [Accepted: 12/28/2006] [Indexed: 02/08/2023]
Abstract
The machinery leading to apoptosis includes altered activity of ion channels. The channels contribute to apoptotic cell shrinkage and modify intracellular ion composition. Cl(-) channels allow the exit of Cl(-), osmolytes and HCO(3)(-) leading to cell shrinkage and cytosolic acidification. K(+) exit through K(+) channels contributes to cell shrinkage and decreases intracellular K(+) concentration, which in turn favours apoptotic cell death. K(+) channel activity further determines the cell membrane potential, a driving force for Ca(2+) entry through Ca(2+) channels. Ca(2+) may enter through unselective cation channels. An increase of cytosolic Ca(2+) may stimulate several enzymes executing apoptosis. Specific ion channel blockers may either promote or counteract suicidal cell death. The present brief review addresses the role of ion channels in the regulation of suicidal cell death with special emphasis on the role of channels in CD95 induced apoptosis of lymphocytes and suicidal death of erythrocytes or eryptosis.
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Affiliation(s)
- Florian Lang
- Department of Physiology, University of Tübingen, Gmelinstrasse 5, D72076 Tuebingen, Germany.
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35
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Lang F, Föller M, Lang K, Lang P, Ritter M, Vereninov A, Szabo I, Huber SM, Gulbins E. Cell volume regulatory ion channels in cell proliferation and cell death. Methods Enzymol 2007; 428:209-25. [PMID: 17875419 DOI: 10.1016/s0076-6879(07)28011-5] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Alterations of cell volume are key events during both cell proliferation and apoptotic cell death. Cell proliferation eventually requires an increase of cell volume, and apoptosis is typically paralleled by cell shrinkage. Alterations of cell volume require the participation of ion transport across the cell membrane, including appropriate activity of Cl(-) and K(+) channels. Cl(-) channels modify cytosolic Cl(-) activity and mediate osmolyte flux, and thus influence cell volume. Most Cl(-) channels allow exit of HCO(3)(-), leading to cytosolic acidification, which in turn inhibits cell proliferation and favors apoptosis. K(+) exit through K(+) channels decreases cytosolic K(+) concentration, which may sensitize the cell for apoptotic cell death. K(+) channel activity further maintains the cell membrane potential, a critical determinant of Ca(2+) entry through Ca(2+) channels. Ca(2+) may, in addition, enter through Ca(2+)-permeable cation channels, which, in some cells, are activated by hyperosmotic shock. Increases of cytosolic Ca(2+) activity may trigger both mechanisms required for cell proliferation and mechanisms, leading to apoptosis. Thereby cell proliferation and apoptosis depend on magnitude and temporal organization of Ca(2+) entry, as well as activity of other signaling pathways. Accordingly, the same ion channels may participate in the stimulation of both cell proliferation and apoptosis. Specific ion channel blockers may thus abrogate both cellular mechanisms, depending on cell type and condition.
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Affiliation(s)
- Florian Lang
- Department of Physiology, University of Tübingen, Germany
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36
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Redman PT, Jefferson BS, Ziegler CB, Mortensen OV, Torres GE, Levitan ES, Aizenman E. A vital role for voltage-dependent potassium channels in dopamine transporter-mediated 6-hydroxydopamine neurotoxicity. Neuroscience 2006; 143:1-6. [PMID: 17027171 PMCID: PMC2673085 DOI: 10.1016/j.neuroscience.2006.08.039] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Revised: 08/09/2006] [Accepted: 08/18/2006] [Indexed: 11/16/2022]
Abstract
6-Hydroxydopamine (6-OHDA), a neurotoxic substrate of the dopamine transporter (DAT), is widely used in Parkinson's disease models. However, the molecular mechanisms underlying 6-OHDA's selectivity for dopamine neurons and the injurious sequelae that it triggers are not well understood. We tested whether ectopic expression of DAT induces sensitivity to 6-OHDA in non-dopaminergic rat cortical neurons and evaluated the contribution of voltage-dependent potassium channel (Kv)-dependent apoptosis to the toxicity of this compound in rat cortical and midbrain dopamine neurons. Cortical neurons expressing DAT accumulated dopamine and were highly vulnerable to 6-OHDA. Pharmacological inhibition of DAT completely blocked this toxicity. We also observed a p38-dependent Kv current surge in DAT-expressing cortical neurons exposed to 6-OHDA, and p38 antagonists and Kv channel blockers were neuroprotective in this model. Thus, DAT-mediated uptake of 6-OHDA recruited the oxidant-induced Kv channel dependent cell death pathway present in cortical neurons. Finally, we report that 6-OHDA also increased Kv currents in cultured midbrain dopamine neurons and this toxicity was blocked with Kv channel antagonists. We conclude that native DAT expression accounts for the dopamine neuron specific toxicity of 6-OHDA. Following uptake, 6-OHDA triggers the oxidant-associated Kv channel-dependent cell death pathway that is conserved in non-dopaminergic cortical neurons and midbrain dopamine neurons.
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Affiliation(s)
- Patrick T. Redman
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Bahiyyah S. Jefferson
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Chandra B. Ziegler
- Department of Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Ole V. Mortensen
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Gonzalo E. Torres
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Edwin S. Levitan
- Department of Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Elias Aizenman
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
- Corresponding author: Dr. Elias Aizenman, Department of Neurobiology, University of Pittsburgh School of Medicine, E1456 BST, Pittsburgh, PA 15261 U.S.A. Tel: (412) 648-9434; fax: (412) 648-1441;
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37
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Abstract
Apoptosis in cortical neurons requires efflux of cytoplasmic potassium mediated by a surge in Kv2.1 channel activity. Pharmacological blockade or molecular disruption of these channels in neurons prevents apoptotic cell death, while ectopic expression of Kv2.1 channels promotes apoptosis in non-neuronal cells. Here, we use a cysteine-containing mutant of Kv2.1 and a thiol-reactive covalent inhibitor to demonstrate that the increase in K+ current during apoptosis is due to de novo insertion of functional channels into the plasma membrane. Biotinylation experiments confirmed the delivery of additional Kv2.1 protein to the cell surface following an apoptotic stimulus. Finally, expression of botulinum neurotoxins that cleave syntaxin and synaptosome-associated protein of 25 kDa (SNAP-25) blocked upregulation of surface Kv2.1 channels in cortical neurons, suggesting that target soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins support proapoptotic delivery of K+ channels. These data indicate that trafficking of Kv2.1 channels to the plasma membrane causes the apoptotic surge in K+ current.
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Affiliation(s)
- SK Pal
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15217, USA
| | - K Takimoto
- Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA 15261, USA
| | - E Aizenman
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15217, USA
- *Corresponding author: E Aizenman, Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15217, USA., Tel: +412-648-9434; Fax: +412-648-1441; E-mail:
| | - ES Levitan
- Department of Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15217, USA
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Zhang Y, Wang H, Li J, Dong L, Xu P, Chen W, Neve RL, Volpe JJ, Rosenberg PA. Intracellular zinc release and ERK phosphorylation are required upstream of 12-lipoxygenase activation in peroxynitrite toxicity to mature rat oligodendrocytes. J Biol Chem 2006; 281:9460-70. [PMID: 16431921 DOI: 10.1074/jbc.m510650200] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Peroxynitrite toxicity has been implicated in the pathogenesis of white matter injury. The mechanisms of peroxynitrite toxicity to oligodendrocytes (OLs), the major cell type of the white matter, are unknown. Using primary cultures of mature OLs that express myelin basic protein, we found that 3-morpholinosydnonimine, a peroxynitrite generator, caused toxicity to OLs. N,N,N',N'-tetrakis (2-pyridylmethyl)ethylenediamine, a zinc chelator, completely blocked peroxynitrite-induced toxicity. Use of FluoZin-3, a specific fluorescence zinc indicator, demonstrated the liberation of zinc from intracellular stores by peroxynitrite. Peroxynitrite caused the sequential activation of extracellular signal-regulated kinase 42/44 (ERK42/44), 12-lipoxygenase, and generation of reactive oxygen species, which were all dependent upon the intracellular release of zinc. The same cell death pathway was also activated when exogenous zinc was used. These results suggest that in addition to preventing the formation of peroxynitrite, useful strategies in preventing disease progression in pathologies in which peroxynitrite toxicity plays a critical role might include maintaining intracellular zinc homeostasis, blocking phosphorylation of ERK42/44, inhibiting activation of 12-lipoxygenase, and eliminating the accumulation of reactive oxygen species.
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Affiliation(s)
- Yumin Zhang
- Department of Neurology and Program in Neuroscience, Children's Hospital and Harvard Medical School, Boston, Mass 02115, USA
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39
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Lang F, Föller M, Lang KS, Lang PA, Ritter M, Gulbins E, Vereninov A, Huber SM. Ion channels in cell proliferation and apoptotic cell death. J Membr Biol 2006; 205:147-57. [PMID: 16362503 DOI: 10.1007/s00232-005-0780-5] [Citation(s) in RCA: 223] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2005] [Indexed: 12/11/2022]
Abstract
Cell proliferation and apoptosis are paralleled by altered regulation of ion channels that play an active part in the signaling of those fundamental cellular mechanisms. Cell proliferation must--at some time point--increase cell volume and apoptosis is typically paralleled by cell shrinkage. Cell volume changes require the participation of ion transport across the cell membrane, including appropriate activity of Cl- and K+ channels. Besides regulating cytosolic Cl- activity, osmolyte flux and, thus, cell volume, most Cl- channels allow HCO3- exit and cytosolic acidification, which inhibits cell proliferation and favors apoptosis. K+ exit through K+ channels may decrease intracellular K+ concentration, which in turn favors apoptotic cell death. K+ channel activity further maintains the cell membrane potential, a critical determinant of Ca2+ entry through Ca2+ channels. Cytosolic Ca2+ may trigger mechanisms required for cell proliferation and stimulate enzymes executing apoptosis. The switch between cell proliferation and apoptosis apparently depends on the magnitude and temporal organization of Ca2+ entry and on the functional state of the cell. Due to complex interaction with other signaling pathways, a given ion channel may play a dual role in both cell proliferation and apoptosis. Thus, specific ion channel blockers may abrogate both fundamental cellular mechanisms, depending on cell type, regulatory environment and condition of the cell. Clearly, considerable further experimental effort is required to fully understand the complex interplay between ion channels, cell proliferation and apoptosis.
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Affiliation(s)
- F Lang
- Department of Physiology, University of Tübingen, Germany.
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40
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Föller M, Kasinathan RS, Duranton C, Wieder T, Huber SM, Lang F. PGE 2-induced Apoptotic Cell Death in K562 Human Leukaemia Cells. Cell Physiol Biochem 2006; 17:201-10. [PMID: 16790996 DOI: 10.1159/000094125] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Prostaglandin-E2 (PGE2) is known to trigger suicidal death of nucleated cells (apoptosis) and enucleated erythrocytes (eryptosis). In erythrocytes PGE2 induced suicidal cell death involves activation of nonselective cation channels leading to Ca2+ entry followed by cell shrinkage and triggering of Ca2+ sensitive cell membrane scrambling with phosphatidylserine (PS) exposure at the cell surface. The present study was performed to explore whether PGE2 induces apoptosis of nucleated cells similarly through cation channel activation and to possibly disclose the molecular identity of the cation channels involved. To this end, Ca2+ activity was estimated from Fluo3 fluorescence, mitochondrial potential from DePsipher fluorescence, phosphatidylserine exposure from annexin binding, caspase activation from caspAce fluorescence, cell volume from FACS forward scatter, and DNA fragmentation utilizing a photometric enzyme immunoassay. Stimulation of K562 human leukaemia cells with PGE2 (50 microM) increased cytosolic Ca2+ activity, decreased forward scatter, depolarized the mitochondrial potential, increased annexin binding, led to caspase activation and resulted in DNA fragmentation. Gene silencing of the Ca2+-permeable transient receptor potential cation channel TRPC7 significantly blunted PGE2-induced triggering of PS exposure and DNA fragmentation. In conclusion, K562 cells express Ca2+-permeable TRPC7 channels, which are activated by PGE2 and participate in the triggering of apoptosis.
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Affiliation(s)
- Michael Föller
- Department of Physiology, University of Tübingen, Germany
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41
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Aras MA, Aizenman E. Obligatory role of ASK1 in the apoptotic surge of K+ currents. Neurosci Lett 2005; 387:136-40. [PMID: 16006035 PMCID: PMC2947746 DOI: 10.1016/j.neulet.2005.06.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2005] [Revised: 06/02/2005] [Accepted: 06/04/2005] [Indexed: 01/26/2023]
Abstract
Apoptosis signal-regulating kinase 1 (ASK1) is a critical component of mitogen-activated protein kinase signaling pathways leading to cell death in response to cytokines and cellular stress. We use a dominant-negative (DN) form of ASK1 to show that this enzyme is necessary for the delayed surge in neuronal K+ channel activity, a required step in apoptosis. Furthermore, expression of ASK1 DN also suppresses the apoptotic increase in Kv2.1 currents transiently expressed in Chinese hamster ovary cells. Finally, over-expression of thioredoxin, an inhibitory binding partner of ASK1, is sufficient to halt the apoptotic current surge in neurons. Thus, ASK1 is an obligatory component of the pro-apoptotic modulation of K+ channels.
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Affiliation(s)
| | - Elias Aizenman
- Corresponding author. Tel.: +1 412 648 9434; fax: +1 412 648 1441. (E. Aizenman)
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42
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Zhang Y, Wang H, Li J, Jimenez DA, Levitan ES, Aizenman E, Rosenberg PA. Peroxynitrite-induced neuronal apoptosis is mediated by intracellular zinc release and 12-lipoxygenase activation. J Neurosci 2005; 24:10616-27. [PMID: 15564577 PMCID: PMC2945223 DOI: 10.1523/jneurosci.2469-04.2004] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Peroxynitrite toxicity is a major cause of neuronal injury in stroke and neurodegenerative disorders. The mechanisms underlying the neurotoxicity induced by peroxynitrite are still unclear. In this study, we observed that TPEN [N,N,N',N'-tetrakis (2-pyridylmethyl)ethylenediamine], a zinc chelator, protected against neurotoxicity induced by exogenous as well as endogenous (coadministration of NMDA and a nitric oxide donor, diethylenetriamine NONOate) peroxynitrite. Two different approaches to detecting intracellular zinc release demonstrated the liberation of zinc from intracellular stores by peroxynitrite. In addition, we found that peroxynitrite toxicity was blocked by inhibitors of 12-lipoxygenase (12-LOX), p38 mitogen-activated protein kinase (MAPK), and caspase-3 and was associated with mitochondrial membrane depolarization. Inhibition of 12-LOX blocked the activation of p38 MAPK and caspase-3. Zinc itself induced the activation of 12-LOX, generation of reactive oxygen species (ROS), and activation of p38 MAPK and caspase-3. These data suggest a cell death pathway triggered by peroxynitrite in which intracellular zinc release leads to activation of 12-LOX, ROS accumulation, p38 activation, and caspase-3 activation. Therefore, therapies aimed at maintaining intracellular zinc homeostasis or blocking activation of 12-LOX may provide a novel avenue for the treatment of inflammation, stroke, and neurodegenerative diseases in which the formation of peroxynitrite is thought to be one of the important causes of cell death.
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Affiliation(s)
- Yumin Zhang
- Department of Neurology and Program in Neuroscience, Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
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Land PW, Aizenman E. Zinc accumulation after target loss: an early event in retrograde degeneration of thalamic neurons. Eur J Neurosci 2005; 21:647-57. [PMID: 15733083 PMCID: PMC2951598 DOI: 10.1111/j.1460-9568.2005.03903.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Accumulation of cytoplasmic zinc is linked with a cascade of events leading to neuronal death. In many in vivo models of zinc-induced cell death, toxic concentrations of synaptically released zinc enter vulnerable neurons via neurotransmitter- or voltage-gated ion channels. In vitro studies demonstrate, in addition, that zinc can be liberated from intracellular stores following oxidative stress and contribute to cell death processes, including apoptosis. Here we describe accumulation of intracellular zinc in an in vivo model of cell death in the absence of presynaptic zinc release. We focused on the lateral geniculate nucleus (LGN) because LGN neurons undergo apoptosis when separated from their target, the primary visual cortex (V1), and the LGN is mostly devoid of zinc-containing presynaptic terminals. Infant and adult rats and adult mice received unilateral ablation of V1, either by aspiration or kainate injection. One to 14 days later, brain sections were stained with selenium autometallography or fluorescently labeled to localize zinc, or stained immunochemically for activated caspase-3. V1 lesions led to zinc accumulation in LGN neurons in infant and adult subjects. Zinc-containing neurons were evident 1-3 days after aspiration lesions, depending on age, but not until 14 days after kainate injection. Zinc accumulation was followed rapidly by immunostaining for activated caspase-3. Our data indicate that like neurotrauma and excitotoxicity, target deprivation leads to accumulation of zinc in apoptotic neurons. Moreover, zinc accumulation in vivo can occur in the absence of presynaptic zinc release. Together these findings suggest that accumulation of intracellular zinc is a ubiquitous component of the cell death cascade in neurons.
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Affiliation(s)
- Peter W Land
- Department of Neurobiology and Center for Neuroscience, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
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