1
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Tuncay E, Aktay I, Turan B. Overexpression of Slc30a7/ZnT7 increases the mitochondrial matrix levels of labile Zn 2+ and modifies histone modification in hyperinsulinemic cardiomyoblasts. J Trace Elem Med Biol 2023; 78:127198. [PMID: 37196548 DOI: 10.1016/j.jtemb.2023.127198] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 04/26/2023] [Accepted: 05/11/2023] [Indexed: 05/19/2023]
Abstract
BACKGROUND Cellular free Zn2+ concentrations ([Zn2+]) are primarily coordinated by Zn2+-transporters, although their roles are not well established in cardiomyocytes. Since we previously showed the important contribution of a Zn2+-transporter ZnT7 to [Zn2+]i regulation in hyperglycemic cardiomyocytes, here, we aimed to examine a possible regulatory role of ZnT7 not only on [Zn2+]i but also both the mitochondrial-free Zn2+ and/or Ca2+ in cardiomyocytes, focusing on the contribution of its overexpression to the mitochondrial function. METHODS We mimicked either hyperinsulinemia (by 50-μM palmitic acid, PA-cells, for 24-h) or overexpressed ZnT7 (ZnT7OE-cells) in H9c2 cardiomyoblasts. RESULTS Opposite to PA-cells, the [Zn2+]i in ZnT7OE-cells was not different from untreated H9c2-cells. An investigation of immunofluorescence imaging by confocal microscopy demonstrated a ZnT7 localization on the mitochondrial matrix. We demonstrated the ZnT7 localization on the mitochondrial matrix by using immunofluorescence imaging. Later, we determined the mitochondrial levels of [Zn2+]Mit and [Ca2+]Mit by using the Zn2+ and Ca2+ sensitive FRET probe and a Ca2+-sensitive dye Fluo4, respectively. The [Zn2+]Mit was found to increase significantly in ZnT7OE-cells, similar to the PA-cells while no significant changes in the [Ca2+]Mit in these cells. To examine the contribution of ZnT7 overexpression on the mitochondria function, we determined the level of reactive oxygen species (ROS) and the mitochondrial membrane potential (MMP) in these cells in comparison to the PA-cells. There were significantly increased production of ROS and depolarization in MMP and increases in marker proteins of mitochondria-associated apoptosis and autophagy in ZnT7-OE cells, similar to the PA-cells, parallel to increases in K-acetylation. Moreover, we determined significant increases in trimethylation of histone H3 lysine27, H3K27me3, and the mono-methylation of histone H3 lysine36, H3K36 in the ZnT7OE-cells, demonstrating the role of [Zn2+]Mit in epigenetic regulation of cardiomyocytes under hyperinsulinemia through histone modification. CONCLUSIONS Overall, our data have shown an important contribution of high expression of ZnT7-OE, through its buffering and muffling capacity in cardiomyocytes, on the regulation of not only [Zn2+]i but also both [Zn2+]Mit and [Ca2+]Mit affecting mitochondria function, in part, via histone modification.
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Affiliation(s)
- Erkan Tuncay
- Department of Biophysics, Ankara University, Faculty of Medicine, Ankara, Turkiye
| | - Irem Aktay
- Department of Biophysics, Ankara University, Faculty of Medicine, Ankara, Turkiye
| | - Belma Turan
- Department of Biophysics, Lokman Hekim University, Faculty of Medicine, Ankara, Turkiye.
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2
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Reiche MA, Aaron JS, Boehm U, DeSantis MC, Hobson CM, Khuon S, Lee RM, Chew TL. When light meets biology - how the specimen affects quantitative microscopy. J Cell Sci 2022; 135:274812. [PMID: 35319069 DOI: 10.1242/jcs.259656] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Fluorescence microscopy images should not be treated as perfect representations of biology. Many factors within the biospecimen itself can drastically affect quantitative microscopy data. Whereas some sample-specific considerations, such as photobleaching and autofluorescence, are more commonly discussed, a holistic discussion of sample-related issues (which includes less-routine topics such as quenching, scattering and biological anisotropy) is required to appropriately guide life scientists through the subtleties inherent to bioimaging. Here, we consider how the interplay between light and a sample can cause common experimental pitfalls and unanticipated errors when drawing biological conclusions. Although some of these discrepancies can be minimized or controlled for, others require more pragmatic considerations when interpreting image data. Ultimately, the power lies in the hands of the experimenter. The goal of this Review is therefore to survey how biological samples can skew quantification and interpretation of microscopy data. Furthermore, we offer a perspective on how to manage many of these potential pitfalls.
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Affiliation(s)
- Michael A Reiche
- Advanced Imaging Center, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA 20147, USA
| | - Jesse S Aaron
- Advanced Imaging Center, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA 20147, USA
| | - Ulrike Boehm
- Advanced Imaging Center, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA 20147, USA
| | - Michael C DeSantis
- Light Microscopy Facility, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA 20147,USA
| | - Chad M Hobson
- Advanced Imaging Center, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA 20147, USA
| | - Satya Khuon
- Advanced Imaging Center, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA 20147, USA.,Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA 20147, USA
| | - Rachel M Lee
- Advanced Imaging Center, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA 20147, USA
| | - Teng-Leong Chew
- Advanced Imaging Center, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA 20147, USA.,Light Microscopy Facility, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA 20147,USA
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3
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Biochemical Studies in Perfundates and Homogenates of Isolated Porcine Kidneys after Flushing with Zinc or Zinc-Prolactin Modified Preservation Solution Using a Static Cold Storage Technique. Molecules 2021; 26:molecules26113465. [PMID: 34200394 PMCID: PMC8200954 DOI: 10.3390/molecules26113465] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 06/04/2021] [Accepted: 06/05/2021] [Indexed: 12/22/2022] Open
Abstract
Zinc is an effective anti-inflammatory and antioxidant trace element. The aim of this study was to analyse the protective effect of zinc and zinc–prolactin systems as additives of preservation solutions in the prevention of nephron damage caused during ischemia. The study used a model for storing isolated porcine kidneys in Biolasol®. The solution was modified with the addition of Zn at a dose of 1 µg/L and Zn: 1 µg/L with prolactin (PRL): 0.1 µg/L. After 2 h and 48 h of storage, the levels of alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, sodium, potassium, creatinine and total protein were determined. Zinc added to the Biolasol® composition at a dose of 1 µg/L showed minor effectiveness in the protection of nephrons. In turn, Zn2+ added to Biolasol + PRL (PRL: 0.1 µg/L) acted as a prolactin inhibitor. We do not recommend the addition of Zn(II) (1 µg/L) and Zn(II) (1 µg/L) + PRL (0.1 µg/L) to the Biolasol solution.
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4
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Özgün A, Garipcan B. Magnetic field-induced Ca 2+ intake by mesenchymal stem cells is mediated by intracellular Zn 2+ and accompanied by a Zn 2+ influx. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119062. [PMID: 34033861 DOI: 10.1016/j.bbamcr.2021.119062] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 05/07/2021] [Accepted: 05/12/2021] [Indexed: 01/21/2023]
Abstract
Chronic exposure to magnetic fields (MFs) has a diverse range of effects on biological systems but definitive molecular mechanisms of the interaction remain largely unknown. One of the most frequently reported effects of MF exposure is an elevated concentration of intracellular Ca2+ through disputed pathways. Other prominent effects include increased oxidative stress and upregulation of neural markers through EGFR activation in stem cells. Further characterization of cascades triggered by MF exposure is hindered by the phenotype diversity of biological models used in the literature. In an attempt to reveal more mechanistic data in this field, we combined the most commonly used biological model and MF parameters with the most commonly reported effects of MFs. Based on clues from the pathways previously defined as sensitive to MFs (EGFR and Zn2+-binding enzymes), the roles of different types of channels (voltage gated Ca2+ channels, NMDA receptors, TRP channels) were inquired in the effects of 50 Hz MFs on bone marrow-derived mesenchymal stem cells. We report that, an influx of Zn2+ accompanies MF-induced Ca2+ intake, which is only attenuated by the broad-range inhibitor of TRP channels and store-operated Ca2+ entry (SOCE), 2-Aminoethoxydiphenyl borate (2-APB) among other blockers (memantine, nifedipine, ethosuximide and gabapentin). Interestingly, cation influx completely disappears when intracellular Zn2+ is chelated. Our results rule out voltage gated Ca2+ channels as a gateway to MF-induced Ca2+ intake and suggest Zn2+-related channels as a new focus in the field.
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Affiliation(s)
- Alp Özgün
- Institute of Biomedical Engineering, Boğaziçi University, Istanbul, Turkey
| | - Bora Garipcan
- Institute of Biomedical Engineering, Boğaziçi University, Istanbul, Turkey.
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5
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The Multifaceted Roles of Zinc in Neuronal Mitochondrial Dysfunction. Biomedicines 2021; 9:biomedicines9050489. [PMID: 33946782 PMCID: PMC8145363 DOI: 10.3390/biomedicines9050489] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/05/2021] [Accepted: 03/07/2021] [Indexed: 12/17/2022] Open
Abstract
Zinc is a highly abundant cation in the brain, essential for cellular functions, including transcription, enzymatic activity, and cell signaling. However, zinc can also trigger injurious cascades in neurons, contributing to the pathology of neurodegenerative diseases. Mitochondria, critical for meeting the high energy demands of the central nervous system (CNS), are a principal target of the deleterious actions of zinc. An increasing body of work suggests that intracellular zinc can, under certain circumstances, contribute to neuronal damage by inhibiting mitochondrial energy processes, including dissipation of the mitochondrial membrane potential (MMP), leading to ATP depletion. Additional consequences of zinc-mediated mitochondrial damage include reactive oxygen species (ROS) generation, mitochondrial permeability transition, and excitotoxic calcium deregulation. Zinc can also induce mitochondrial fission, resulting in mitochondrial fragmentation, as well as inhibition of mitochondrial motility. Here, we review the known mechanisms responsible for the deleterious actions of zinc on the organelle, within the context of neuronal injury associated with neurodegenerative processes. Elucidating the critical contributions of zinc-induced mitochondrial defects to neurotoxicity and neurodegeneration may provide insight into novel therapeutic targets in the clinical setting.
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6
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Choi DW. Excitotoxicity: Still Hammering the Ischemic Brain in 2020. Front Neurosci 2020; 14:579953. [PMID: 33192266 PMCID: PMC7649323 DOI: 10.3389/fnins.2020.579953] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/25/2020] [Indexed: 12/13/2022] Open
Abstract
Interest in excitotoxicity expanded following its implication in the pathogenesis of ischemic brain injury in the 1980s, but waned subsequent to the failure of N-methyl-D-aspartate (NMDA) antagonists in high profile clinical stroke trials. Nonetheless there has been steady progress in elucidating underlying mechanisms. This review will outline the historical path to current understandings of excitotoxicity in the ischemic brain, and suggest that this knowledge should be leveraged now to develop neuroprotective treatments for stroke.
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Affiliation(s)
- Dennis W Choi
- Department of Neurology, SUNY Stony Brook, Stony Brook, NY, United States
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7
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Huang Q, Wang X, Lin X, Zhang J, You X, Shao A. The Role of Transient Receptor Potential Channels in Blood-Brain Barrier Dysfunction after Ischemic Stroke. Biomed Pharmacother 2020; 131:110647. [PMID: 32858500 DOI: 10.1016/j.biopha.2020.110647] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 08/11/2020] [Accepted: 08/16/2020] [Indexed: 12/25/2022] Open
Abstract
Stroke is the leading cause of long-term disability, demanding an ever-increasing need to find treatment. Transient receptor potential (TRP) channels are nonselective Ca2+-permeable channels, among which TRPC, TRPM, and TRPV are widely expressed in the brain. Dysfunction of the blood brain barrier (BBB) is a core feature of stroke and is associated with severity of injury. As studies have shown, TRP channels influence various neuronal functions by regulating the BBB. Here, we briefly review the role of TRP channel in the BBB dysfunction after stroke, and explore the therapeutic potential of TRP-targeted therapy.
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Affiliation(s)
- Qingxia Huang
- Department of Echocardiography, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoyu Wang
- Department of Neurosurgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Xianyi Lin
- Department of anesthesiology, Sir run run shaw hospital, school of medicine, zhejiang university, China
| | - Jianmin Zhang
- Department of Neurosurgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China; Brain Research Institute, Zhejiang University, Hangzhou, China; Collaborative Innovation Center for Brain Science, Zhejiang University, Hangzhou, China
| | - Xiangdong You
- Department of Echocardiography, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.
| | - Anwen Shao
- Department of Neurosurgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China.
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8
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Yin HZ, Wang HL, Ji SG, Medvedeva YV, Tian G, Bazrafkan AK, Maki NZ, Akbari Y, Weiss JH. Rapid Intramitochondrial Zn2+ Accumulation in CA1 Hippocampal Pyramidal Neurons After Transient Global Ischemia: A Possible Contributor to Mitochondrial Disruption and Cell Death. J Neuropathol Exp Neurol 2020; 78:655-664. [PMID: 31150090 DOI: 10.1093/jnen/nlz042] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Mitochondrial Zn2+ accumulation, particularly in CA1 neurons, occurs after ischemia and likely contributes to mitochondrial dysfunction and subsequent neurodegeneration. However, the relationship between mitochondrial Zn2+ accumulation and their disruption has not been examined at the ultrastructural level in vivo. We employed a cardiac arrest model of transient global ischemia (TGI), combined with Timm's sulfide silver labeling, which inserts electron dense metallic silver granules at sites of labile Zn2+ accumulation, and used transmission electron microscopy (TEM) to examine subcellular loci of the Zn2+ accumulation. In line with prior studies, TGI-induced damage to CA1 was far greater than to CA3 pyramidal neurons, and was substantially progressive in the hours after reperfusion (being significantly greater after 4- than 1-hour recovery). Intriguingly, TEM examination of Timm's-stained sections revealed substantial Zn2+ accumulation in many postischemic CA1 mitochondria, which was strongly correlated with their swelling and disruption. Furthermore, paralleling the evolution of neuronal injury, both the number of mitochondria containing Zn2+ and the degree of their disruption were far greater at 4- than 1-hour recovery. These data provide the first direct characterization of Zn2+ accumulation in CA1 mitochondria after in vivo TGI, and support the idea that targeting these events could yield therapeutic benefits.
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Affiliation(s)
| | | | - Sung G Ji
- Department of Anatomy & Neurobiology, University of California, Irvine, Irvine, California
| | | | | | | | | | | | - John H Weiss
- Department of Neurology
- Department of Anatomy & Neurobiology, University of California, Irvine, Irvine, California
- Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan
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9
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Noh J, Chung JM. Modulation of Dopaminergic Neuronal Excitability by Zinc through the Regulation of Calcium-related Channels. Exp Neurobiol 2019; 28:578-592. [PMID: 31698550 PMCID: PMC6844832 DOI: 10.5607/en.2019.28.5.578] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 10/28/2019] [Accepted: 10/28/2019] [Indexed: 11/19/2022] Open
Abstract
Depending on the intracellular buffering of calcium by chelation, zinc has the following two apparent effects on neuronal excitability: enhancement or reduction. Zinc increased tonic activity in the depolarized state when neurons were intracellularly dialyzed with EGTA but attenuated the neuronal activity when BAPTA was used as an intracellular calcium buffer. This suggests that neuronal excitability can be modulated by zinc, depending on the internal calcium buffering capacity. In this study, we elucidated the mechanisms of zinc-mediated alterations in neuronal excitability and determined the effect of calcium-related channels on zinc-mediated alterations in excitability. The zinc-induced augmentation of firing activity was mediated via the inhibition of small-conductance calcium-activated potassium (SK) channels with not only the contribution of voltage-gated L-type calcium channels (VGCCs) and ryanodine receptors (RyRs), but also through the activation of VGCCs via melastatin-like transient receptor potential channels. We suggest that zinc modulates the dopaminergic neuronal activity by regulating not only SK channels as calcium sensors, but also VGCCs or RyRs as calcium sources. Our results suggest that the cytosolic calcium-buffering capacity can tightly regulate zinc-induced neuronal firing patterns and that local calcium-signaling domains can determine the physiological and pathological state of synaptic activity in the dopaminergic system.
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Affiliation(s)
- Jihyun Noh
- Department of Science Education, Dankook University, Yongin 16890, Korea
| | - Jun-Mo Chung
- Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul 03760, Korea
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10
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Tuo QZ, Liuyang ZY, Lei P, Yan X, Shentu YP, Liang JW, Zhou H, Pei L, Xiong Y, Hou TY, Zhou XW, Wang Q, Wang JZ, Wang XC, Liu R. Zinc induces CDK5 activation and neuronal death through CDK5-Tyr15 phosphorylation in ischemic stroke. Cell Death Dis 2018; 9:870. [PMID: 30158515 PMCID: PMC6115431 DOI: 10.1038/s41419-018-0929-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 07/09/2018] [Accepted: 07/16/2018] [Indexed: 02/05/2023]
Abstract
CDK5 activation promotes ischemic neuronal death in stroke, with the recognized activation mechanism being calpain-dependent p35 cleavage to p25. Here we reported that CDK5-Tyr15 phosphorylation by zinc induced CDK5 activation in brain ischemic injury. CDK5 activation and CDK5-Tyr15 phosphorylation were observed in the hippocampus of the rats that had been subjected to middle cerebral artery occlusion, both of which were reversed by pretreatment with zinc chelator; while p35 cleavage and calpain activation in ischemia were not reversed. Zinc incubation resulted in CDK5-Tyr15 phosphorylation and CDK5 activation, without increasing p35 cleavage in cultured cells. Site mutation experiment confirmed that zinc-induced CDK5 activation was dependent on Tyr15 phosphorylation. Further exploration showed that Src kinase contributed to zinc-induced Tyr15 phosphorylation and CDK5 activation. Src kinase inhibition or expression of an unphosphorylable mutant Y15F-CDK5 abolished Tyr15 phosphorylation, prevented CDK5 activation and protected hippocampal neurons from ischemic insult in rats. We conclude that zinc-induced CDK5-Tyr15 phosphorylation underlies CDK5 activation and promotes ischemic neuronal death in stroke.
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Affiliation(s)
- Qing-Zhang Tuo
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Neurology and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Sichuan, China
| | - Zhen-Yu Liuyang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Peng Lei
- Department of Neurology and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy, Sichuan, China
| | - Xiong Yan
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yang-Ping Shentu
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jia-Wei Liang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Huan Zhou
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lei Pei
- The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan, China
| | - Yan Xiong
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Tong-Yao Hou
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xin-Wen Zhou
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qun Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jian-Zhi Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiao-Chuan Wang
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Rong Liu
- Department of Pathophysiology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. .,The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan, China.
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11
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Park SE, Song JH, Hong C, Kim DE, Sul JW, Kim TY, Seo BR, So I, Kim SY, Bae DJ, Park MH, Lim HM, Baek IJ, Riccio A, Lee JY, Shim WH, Park B, Koh JY, Hwang JJ. Contribution of Zinc-Dependent Delayed Calcium Influx via TRPC5 in Oxidative Neuronal Death and its Prevention by Novel TRPC Antagonist. Mol Neurobiol 2018; 56:2822-2835. [PMID: 30062674 PMCID: PMC6459797 DOI: 10.1007/s12035-018-1258-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 07/17/2018] [Indexed: 11/29/2022]
Abstract
Oxidative stress is a key mediator of neuronal death in acute brain injuries, such as epilepsy, trauma, and stroke. Although it is accompanied by diverse cellular changes, increases in levels of intracellular zinc ion (Zn2+) and calcium ion (Ca2+) may play a critical causative role in oxidative neuronal death. However, the mechanistic link between Zn2+ and Ca2+ dyshomeostasis in neurons during oxidative stress is not well-understood. Here, we show that the exposure of cortical neurons to H2O2 led to a zinc-triggered calcium influx, which resulted in neuronal death. The cyclin-dependent kinase inhibitor, NU6027, inhibited H2O2-induced Ca2+ increases and subsequent cell death in cortical neurons, without affecting the early increase in Zn2+. Therefore, we attempted to identify the zinc-regulated Ca2+ pathway that was inhibited by NU6027. The expression profile in cortical neurons identified transient receptor potential cation channel 5 (TRPC5) as a candidate that is known to involve in the generation of epileptiform burst firing and epileptic neuronal death (Phelan KD et al. 2012a; Phelan KD et al. 2013b). NU6027 inhibited basal and zinc-augmented TRPC5 currents in TRPC5-overexpressing HEK293 cells. Consistently, cortical neurons from TRPC5 knockout mice were highly resistant to H2O2-induced death. Moreover, NU6027 is neuroprotective in kainate-treated epileptic rats. Our results demonstrate that TRPC5 is a novel therapeutic target against oxidative neuronal injury in prolonged seizures and that NU6027 is a potent inhibitor of TRPC5.
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Affiliation(s)
- Sang Eun Park
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea
| | - Ji Hoon Song
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea
| | - Chansik Hong
- Department of Physiology, Chosun University School of Medicine, Kwangju, 61452, South Korea
| | - Dong Eun Kim
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea
| | - Jee-Won Sul
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea
| | - Tae-Youn Kim
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea.,Neural Injury Research Lab, University of Ulsan College of Medicine, Seoul, 05505, South Korea
| | - Bo-Ra Seo
- Neural Injury Research Lab, University of Ulsan College of Medicine, Seoul, 05505, South Korea
| | - Insuk So
- Department of Physiology and Institute of Dermatological Science, Seoul National University College of Medicine, Seoul, 110-799, South Korea
| | - Sang-Yeob Kim
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea.,Department of Convergence Medicine, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-Gu, Seoul, 05505, South Korea
| | - Dong-Jun Bae
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea
| | - Mi-Ha Park
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea
| | - Hye Min Lim
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea
| | - In-Jeoung Baek
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea.,Department of Convergence Medicine, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-Gu, Seoul, 05505, South Korea
| | - Antonio Riccio
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA.,Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Joo-Yong Lee
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea.,Department of Convergence Medicine, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-Gu, Seoul, 05505, South Korea
| | - Woo Hyun Shim
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea.,Department of Convergence Medicine, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-Gu, Seoul, 05505, South Korea
| | - Bumwoo Park
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea.,Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
| | - Jae-Young Koh
- Neural Injury Research Lab, University of Ulsan College of Medicine, Seoul, 05505, South Korea. .,Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-Gu, Seoul, 05505, South Korea.
| | - Jung Jin Hwang
- Asan Institute for Life Sciences, Asan Medical Center, Seoul, 05505, South Korea. .,Department of Convergence Medicine, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-Gu, Seoul, 05505, South Korea.
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12
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Körschgen H, Kuske M, Karmilin K, Yiallouros I, Balbach M, Floehr J, Wachten D, Jahnen-Dechent W, Stöcker W. Intracellular activation of ovastacin mediates pre-fertilization hardening of the zona pellucida. Mol Hum Reprod 2018; 23:607-616. [PMID: 28911209 DOI: 10.1093/molehr/gax040] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 07/17/2017] [Indexed: 01/07/2023] Open
Abstract
STUDY QUESTION How and where is pro-ovastacin activated and how does active ovastacin regulate zona pellucida hardening (ZPH) and successful fertilization? STUDY FINDING Ovastacin is partially active before exocytosis and pre-hardens the zona pellucida (ZP) before fertilization. WHAT IS KNOWN ALREADY The metalloproteinase ovastacin is stored in cortical granules, it cleaves zona pellucida protein 2 (ZP2) upon fertilization and thereby destroys the ZP sperm ligand and triggers ZPH. Female mice deficient in the extracellular circulating ovastacin-inhibitor fetuin-B are infertile due to pre-mature ZPH. STUDY DESIGN, SAMPLES/MATERIALS, METHODS We isolated oocytes from wild-type and ovastacin-deficient (Astlnull) FVB mice before and after fertilization (in vitro and in vivo) and quantified ovastacin activity and cleavage of ZP2 by immunoblot. We assessed ZPH by measuring ZP digestion time using α-chymotrypsin and by determining ZP2 cleavage. We determined cellular distribution of ovastacin by immunofluorescence using domain-specific ovastacin antibodies. Experiments were performed at least in triplicate with a minimum of 20 oocytes. Data were pre-analyzed using Shapiro-Wilk test. In case of normal distribution, significance was determined via two-sided Student's t-test, whereas in case of non-normal distribution via Mann-Whitney U-test. MAIN RESULTS AND THE ROLE OF CHANCE Metaphase II (MII) oocytes contained both inactive pro-ovastacin and activated ovastacin. Immunoblot and ZP digestion assays revealed a partial cleavage of ZP2 even before fertilization in wild-type mice. Partial cleavage coincided with germinal-vesicle breakdown and MII, despite the presence of fetuin-B protein, an endogenous ovastacin inhibitor, in the follicular and oviductal fluid. Upon exocytosis, part of the C-terminal domain of ovastacin remained attached to the plasmalemma, while the N-terminal active ovastacin domain was secreted. This finding may resolve previously conflicting data showing that ovastacin acts both as an oolemmal receptor termed SAS1B (sperm acrosomal SLLP1 binding protein; SLLP, sperm lysozyme like protein) and a secreted protease mediating ZP2 cleavage. LIMITATIONS, REASONS FOR CAUTION For this study, only oocytes isolated from wild-type and ovastacin-deficient FVB mice were investigated. Some experiments involved oocyte activation by the Ca2+ ionophore A23187 to trigger ZPH. WIDER IMPLICATIONS OF THE FINDINGS This study provides a detailed spatial and temporal view of pre-mature cleavage of ZP2 by ovastacin, which is known to adversely affect IVF rate in mice and humans. LARGE SCALE DATA None. STUDY FUNDING AND COMPETING INTEREST(S) This work was supported by the Center of Natural Sciences and Medicine and by a start-up grant of the Johannes Gutenberg University Mainz to W.S., and by a grant from Deutsche Forschungsgemeinschaft and by the START program of the Medical Faculty of RWTH Aachen University to J.F. and W.J.D. There are no competing interests to declare.
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Affiliation(s)
- Hagen Körschgen
- Institute of Molecular Physiology, Department of Biology, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - Michael Kuske
- Institute of Molecular Physiology, Department of Biology, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - Konstantin Karmilin
- Institute of Molecular Physiology, Department of Biology, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - Irene Yiallouros
- Institute of Molecular Physiology, Department of Biology, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
| | - Melanie Balbach
- Max-Planck Research Group Molecular Physiology, Center of Advanced European Studies And Research (CAESAR), 53175 Bonn, Germany
| | - Julia Floehr
- Biointerface Laboratory, Helmholtz-Institute for Biomedical Engineering, 52074 Aachen, Germany
| | - Dagmar Wachten
- Max-Planck Research Group Molecular Physiology, Center of Advanced European Studies And Research (CAESAR), 53175 Bonn, Germany.,Institute of Innate Immunity, University Hospital, University of Bonn, 53175 Bonn, Germany
| | - Willi Jahnen-Dechent
- Biointerface Laboratory, Helmholtz-Institute for Biomedical Engineering, 52074 Aachen, Germany
| | - Walter Stöcker
- Institute of Molecular Physiology, Department of Biology, Johannes Gutenberg-University Mainz, 55099 Mainz, Germany
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13
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Ji SG, Medvedeva YV, Wang HL, Yin HZ, Weiss JH. Mitochondrial Zn 2+ Accumulation: A Potential Trigger of Hippocampal Ischemic Injury. Neuroscientist 2018; 25:126-138. [PMID: 29742958 DOI: 10.1177/1073858418772548] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Ischemic stroke is a major cause of death and disabilities worldwide, and it has been long hoped that improved understanding of relevant injury mechanisms would yield targeted neuroprotective therapies. While Ca2+ overload during ischemia-induced glutamate excitotoxicity has been identified as a major contributor, failures of glutamate targeted therapies to achieve desired clinical efficacy have dampened early hopes for the development of new treatments. However, additional studies examining possible contributions of Zn2+, a highly prevalent cation in the brain, have provided new insights that may help to rekindle the enthusiasm. In this review, we discuss both old and new findings yielding clues as to sources of the Zn2+ that accumulates in many forebrain neurons after ischemia, and mechanisms through which it mediates injury. Specifically, we highlight the growing evidence of important Zn2+ effects on mitochondria in promoting neuronal injury. A key focus has been to examine Zn2+ contributions to the degeneration of highly susceptible hippocampal pyramidal neurons. Recent studies provide evidence of differences in sources of Zn2+ and its interactions with mitochondria in CA1 versus CA3 neurons that may pertain to their differential vulnerabilities in disease. We propose that Zn2+-induced mitochondrial dysfunction is a critical and potentially targetable early event in the ischemic neuronal injury cascade, providing opportunities for the development of novel neuroprotective strategies to be delivered after transient ischemia.
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Affiliation(s)
- Sung G Ji
- 1 Department of Anatomy & Neurobiology, University of California, Irvine, CA, USA
| | | | - Hwai-Lee Wang
- 2 Department of Neurology, University of California, Irvine, CA, USA.,3 Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan
| | - Hong Z Yin
- 2 Department of Neurology, University of California, Irvine, CA, USA
| | - John H Weiss
- 1 Department of Anatomy & Neurobiology, University of California, Irvine, CA, USA.,2 Department of Neurology, University of California, Irvine, CA, USA
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14
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Ji SG, Weiss JH. Zn 2+-induced disruption of neuronal mitochondrial function: Synergism with Ca 2+, critical dependence upon cytosolic Zn 2+ buffering, and contributions to neuronal injury. Exp Neurol 2018; 302:181-195. [PMID: 29355498 DOI: 10.1016/j.expneurol.2018.01.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 12/15/2017] [Accepted: 01/15/2018] [Indexed: 10/18/2022]
Abstract
Excitotoxic Zn2+ and Ca2+ accumulation contributes to neuronal injury after ischemia or prolonged seizures. Synaptically released Zn2+ can enter postsynaptic neurons via routes including voltage sensitive Ca2+ channels (VSCC), and, more rapidly, through Ca2+ permeable AMPA channels. There are also intracellular Zn2+ binding proteins which can either buffer neuronal Zn2+ influx or release bound Zn2+ into the cytosol during pathologic conditions. Studies in culture highlight mitochondria as possible targets of Zn2+; cytosolic Zn2+ can enter mitochondria and induce effects including loss of mitochondrial membrane potential (ΔΨm), mitochondrial swelling, and reactive oxygen species (ROS) generation. While brief (5 min) neuronal depolarization (to activate VSCC) in the presence of 300 μM Zn2+ causes substantial delayed neurodegeneration, it only mildly impacts acute mitochondrial function, raising questions as to contributions of Zn2+-induced mitochondrial dysfunction to neuronal injury. Using brief high (90 mM) K+/Zn2+ exposures to mimic neuronal depolarization and extracellular Zn2+ accumulation as may accompany ischemia in vivo, we examined effects of disrupted cytosolic Zn2+ buffering and/or the presence of Ca2+, and made several observations: 1. Mild disruption of cytosolic Zn2+ buffering-while having little effects alone-markedly enhanced mitochondrial Zn2+ accumulation and dysfunction (including loss of ∆Ψm, ROS generation, swelling and respiratory inhibition) caused by relatively low (10-50 μM) Zn2+ with high K+. 2. The presence of Ca2+ during the Zn2+ exposure decreased cytosolic and mitochondrial Zn2+ accumulation, but markedly exacerbated the consequent dysfunction. 3. Paralleling effects on mitochondria, disruption of buffering and presence of Ca2+ enhanced Zn2+-induced neurodegeneration. 4. Zn2+ chelation after the high K+/Zn2+ exposure attenuated both ROS production and neurodegeneration, supporting the potential utility of delayed interventions. Taken together, these data lend credence to the idea that in pathologic states that impair cytosolic Zn2+ buffering, slow uptake of Zn2+ along with Ca2+ into neurons via VSCC can disrupt the mitochondria and induce neurodegeneration.
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Affiliation(s)
- Sung G Ji
- Department of Anatomy & Neurobiology, University of California, Irvine, USA
| | - John H Weiss
- Department of Anatomy & Neurobiology, University of California, Irvine, USA; Department of Neurology, University of California, Irvine, USA.
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15
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Takeda A, Tamano H. The Impact of Synaptic Zn 2+ Dynamics on Cognition and Its Decline. Int J Mol Sci 2017; 18:ijms18112411. [PMID: 29135924 PMCID: PMC5713379 DOI: 10.3390/ijms18112411] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 10/31/2017] [Accepted: 11/09/2017] [Indexed: 11/16/2022] Open
Abstract
The basal levels of extracellular Zn2+ are in the range of low nanomolar concentrations and less attention has been paid to Zn2+, compared to Ca2+, for synaptic activity. However, extracellular Zn2+ is necessary for synaptic activity. The basal levels of extracellular zinc are age-dependently increased in the rat hippocampus, implying that the basal levels of extracellular Zn2+ are also increased age-dependently and that extracellular Zn2+ dynamics are linked with age-related cognitive function and dysfunction. In the hippocampus, the influx of extracellular Zn2+ into postsynaptic neurons, which is often linked with Zn2+ release from neuron terminals, is critical for cognitive activity via long-term potentiation (LTP). In contrast, the excess influx of extracellular Zn2+ into postsynaptic neurons induces cognitive decline. Interestingly, the excess influx of extracellular Zn2+ more readily occurs in aged dentate granule cells and intracellular Zn2+-buffering, which is assessed with ZnAF-2DA, is weakened in the aged dentate granule cells. Characteristics (easiness) of extracellular Zn2+ influx seem to be linked with the weakened intracellular Zn2+-buffering in the aged dentate gyrus. This paper deals with the impact of synaptic Zn2+ signaling on cognition and its decline in comparison with synaptic Ca2+ signaling.
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Affiliation(s)
- Atsushi Takeda
- Department of Neurophysiology, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
| | - Hanuna Tamano
- Department of Neurophysiology, School of Pharmaceutical Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan.
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16
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Wang Z, Yu X, Li YV. Zinc chelation promotes streptokinase-induced thrombolysis in vitro. INTERNATIONAL JOURNAL OF PHYSIOLOGY, PATHOPHYSIOLOGY AND PHARMACOLOGY 2017; 9:137-146. [PMID: 29209450 PMCID: PMC5698690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 10/16/2017] [Indexed: 06/07/2023]
Abstract
Cardiovascular disorder occurs when a local blood clot obstructs an artery or a vein to its surround organs, causing related tissues to lose function and die. It is one of the leading causes of mortality and a major cause of disability. The effect of thrombolysis induced by injecting intravenous thrombolytic agents is critical for reducing tissue damages. Streptokinase (SK) is a widely used thrombolytic agent in the treatment of thromboembolism in the blood vessels. A high unit of streptokinase is used in thrombolytic therapies for thrombotic disorders and could improve tissue reperfusion. It is a potent plasminogen activator. However, safety concerns for the usage of a high unit of streptokinase have been raised for the hemorrhagic transformation. In the present study, we studied how zinc would affect streptokinase-induced thrombolysis in vitro, and proposed a strategy to improve streptokinase's effectiveness in promoting thrombolysis. The mice whole blood was used to form the blood clot in vitro by incubating with calcium at 37°C for 30 minutes. Streptokinase was used for inducing thrombolysis measured with the spectrophotometer. Zinc and its chelator, Ca-EDTA, were applied with streptokinase, respectively. Results showed that the co-application zinc inhibited the thrombolytic effect of streptokinase in a dose-dependent manner. Zinc chelator, Ca-EDTA, significantly increased the effect of streptokinase-induced thrombolysis. Our results suggest that zinc chelation improved the efficiency of streptokinase in thrombolysis. The results may have a significant clinical implication by potentially reducing the adverse effect of streptokinase application.
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Affiliation(s)
- Zihui Wang
- Department of Biological Sciences, Ohio UniversityAthens Ohio, USA
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio UniversityAthens Ohio, USA
| | - Xinge Yu
- Department of Biological Sciences, Ohio UniversityAthens Ohio, USA
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio UniversityAthens Ohio, USA
| | - Yang V Li
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio UniversityAthens Ohio, USA
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17
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Zieminska E, Ruszczynska A, Lazarewicz JW. Tetrabromobisphenol A disturbs zinc homeostasis in cultured cerebellar granule cells: A dual role in neurotoxicity. Food Chem Toxicol 2017; 109:363-375. [PMID: 28919410 DOI: 10.1016/j.fct.2017.09.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 09/11/2017] [Accepted: 09/12/2017] [Indexed: 01/15/2023]
Abstract
The brominated flame retardant tetrabromobisphenol A (TBBPA) has recognized neurotoxic properties mediated by intracellular Ca2+ imbalance and oxidative stress. Although these factors are known to trigger the release of Zn2+ from intracellular stores, the effects of TBBPA on Zn2+ homeostasis in neurons and the role of Zn2+in TBBPA neurotoxicity have not yet been studied. Therefore, we investigated zinc transients in primary cultures of rat cerebellar granule cells and assessed their involvement in TBBPA neurotoxicity. The results demonstrate that TBBPA releases Zn2+ from the intracellular stores and increases its intracellular concentration, followed by Zn2+ displacement from the cells. TBBPA-evoked Zn2+ transients are partially mediated by Ca2+ and ROS. Application of TPEN, Zn2+ chelator, potentiates TBBPA- and glutamate-induced 45Ca uptake, enhances TBBPA-induced ROS production and potentiates decreases in the ΔΨm in cells treated with 25 μM TBBPA, revealing the potential neuroprotective capacity of endogenous Zn2+. However, the administration of TPEN does not aggravate TBBPA neurotoxicity, and even slightly decreases neuronal death induced by 25 μM TBBPA. In summary, it was shown for the first time that TBBPA interferes with the cellular Zn2+ homeostasis in neuronal cultures, and we revealed complex roles for endogenous Zn2+ in cytoprotection and TBBPA toxicity in cultured neurons.
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Affiliation(s)
- Elzbieta Zieminska
- Department of Neurochemistry, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.
| | - Anna Ruszczynska
- University of Warsaw, Faculty of Chemistry, Biological and Chemical Research Centre, Warsaw, Poland
| | - Jerzy W Lazarewicz
- Department of Neurochemistry, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
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18
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Differential Vulnerability of CA1 versus CA3 Pyramidal Neurons After Ischemia: Possible Relationship to Sources of Zn2+ Accumulation and Its Entry into and Prolonged Effects on Mitochondria. J Neurosci 2017; 37:726-737. [PMID: 28100752 DOI: 10.1523/jneurosci.3270-16.2016] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 11/23/2016] [Accepted: 11/29/2016] [Indexed: 12/28/2022] Open
Abstract
Excitotoxic mechanisms contribute to the degeneration of hippocampal pyramidal neurons after recurrent seizures and brain ischemia. However, susceptibility differs, with CA1 neurons degenerating preferentially after global ischemia and CA3 neurons after limbic seizures. Whereas most studies address contributions of excitotoxic Ca2+ entry, it is apparent that Zn2+ also contributes, reflecting accumulation in neurons either after synaptic release and entry through postsynaptic channels or upon mobilization from intracellular Zn2+-binding proteins such as metallothionein-III (MT-III). Using mouse hippocampal slices to study acute oxygen glucose deprivation (OGD)-triggered neurodegeneration, we found evidence for early contributions of excitotoxic Ca2+ and Zn2+ accumulation in both CA1 and CA3, as indicated by the ability of Zn2+ chelators or Ca2+ entry blockers to delay pyramidal neuronal death in both regions. However, using knock-out animals (of MT-III and vesicular Zn2+ transporter, ZnT3) and channel blockers revealed substantial differences in relevant Zn2+ sources, with critical contributions of presynaptic release and its permeation through Ca2+- (and Zn2+)-permeable AMPA channels in CA3 and Zn2+ mobilization from MT-III predominating in CA1. To assess the consequences of the intracellular Zn2+ accumulation, we used OGD exposures slightly shorter than those causing acute neuronal death; under these conditions, cytosolic Zn2+ rises persisted for 10-30 min after OGD, followed by recovery over ∼40-60 min. Furthermore, the recovery appeared to be accompanied by mitochondrial Zn2+ accumulation (via the mitochondrial Ca2+ uniporter MCU) in CA1 but not in CA3 neurons and was markedly diminished in MT-III knock-outs, suggesting that it depended upon Zn2+ mobilization from this protein. SIGNIFICANCE STATEMENT The basis for the differential vulnerabilities of CA1 versus CA3 pyramidal neurons is unclear. The present study of events during and after acute oxygen glucose deprivation highlights a possible important difference, with rapid synaptic entry of Ca2+ and Zn2+ contributing more in CA3, but with delayed and long-lasting accumulation of Zn2+ within mitochondria occurring in CA1 but not CA3 pyramidal neurons. These data may be consistent with observations of prominent mitochondrial dysfunction as a critical early event in the delayed degeneration of CA1 neurons after ischemia and support a hypothesis that mitochondrial Zn2+ accumulation in the early reperfusion period may be a critical and targetable upstream event in the injury cascade.
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19
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Slepchenko KG, Lu Q, Li YV. Cross talk between increased intracellular zinc (Zn 2+) and accumulation of reactive oxygen species in chemical ischemia. Am J Physiol Cell Physiol 2017; 313:C448-C459. [PMID: 28747335 DOI: 10.1152/ajpcell.00048.2017] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 07/21/2017] [Accepted: 07/21/2017] [Indexed: 12/16/2022]
Abstract
Both zinc (Zn2+) and reactive oxygen species (ROS) have been shown to accumulate during hypoxic-ischemic stress and play important roles in pathological processes. To understand the cross talk between the two of them, here we studied Zn2+ and ROS accumulation by employing fluorescent probes in HeLa cells to further the understanding of the cause and effect relationship of these two important cellular signaling systems during chemical-ischemia, stimulated by oxygen and glucose deprivation (OGD). We observed two Zn2+ rises that were divided into four phases in the course of 30 min of OGD. The first Zn2+ rise was a transient, which was followed by a latent phase during which Zn2+ levels recovered; however, levels remained above a basal level in most cells. The final phase was the second Zn2+ rise, which reached a sustained plateau called Zn2+ overload. Zn2+ rises were not observed when Zn2+ was removed by TPEN (a Zn2+ chelator) or thapsigargin (depleting Zn2+ from intracellular stores) treatment, indicating that Zn2+ was from intracellular storage. Damaging mitochondria with FCCP significantly reduced the second Zn2+ rise, indicating that the mitochondrial Zn2+ accumulation contributes to Zn2+ overload. We also detected two OGD-induced ROS rises. Two Zn2+ rises preceded two ROS rises. Removal of Zn2+ reduced or delayed OGD- and FCCP-induced ROS generation, indicating that Zn2+ contributes to mitochondrial ROS generation. There was a Zn2+-induced increase in the functional component of NADPH oxidase, p47phox, thus suggesting that NADPH oxidase may mediate Zn2+-induced ROS accumulation. We suggest a new mechanism of cross talk between Zn2+ and mitochondrial ROS through positive feedback processes that eventually causes excessive free Zn2+ and ROS accumulations during the course of ischemic stress.
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Affiliation(s)
- Kira G Slepchenko
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio; and
| | - Qiping Lu
- Department of Biological Sciences, College of Arts and Sciences, Ohio University, Athens, Ohio
| | - Yang V Li
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio; and
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20
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Alaverdashvili M, Paterson PG. Mapping the dynamics of cortical neuroplasticity of skilled motor learning using micro X-ray fluorescence and histofluorescence imaging of zinc in the rat. Behav Brain Res 2016; 318:52-60. [PMID: 27840249 DOI: 10.1016/j.bbr.2016.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 10/26/2016] [Accepted: 11/01/2016] [Indexed: 11/26/2022]
Abstract
Synchrotron-based X-ray fluorescence imaging (XFI) of zinc (Zn) has been recently implemented to understand the efficiency of various therapeutic interventions targeting post-stroke neuroprotection and neuroplasticity. However, it is uncertain if micro XFI can resolve neuroplasticity-induced changes. Thus, we explored if learning-associated behavioral changes would be accompanied by changes in cortical Zn concentration measured by XFI in healthy adult rats. Proficiency in a skilled reach-to-eat task during early and late stages of motor learning served as a functional measure of neuroplasticity. c-Fos protein and vesicular Zn expression were employed as indirect neuronal measures of brain plasticity. A total Zn map (20×20×30μm3 resolution) generated by micro XFI failed to reflect increases in either c-Fos or vesicular Zn in the motor cortex contralateral to the trained forelimb or improved proficiency in the skilled reaching task. Remarkably, vesicular Zn increased in the late stage of motor learning along with a concurrent decrease in the number of c-fos-ip neurons relative to the early stage of motor learning. This inverse dynamics of c-fos and vesicular Zn level as the motor skill advances suggest that a qualitatively different neural population, comprised of fewer active but more efficiently connected neurons, supports a skilled action in the late versus early stage of motor learning. The lack of sensitivity of the XFI-generated Zn map to visualize the plasticity-associated changes in vesicular Zn suggests that the Zn level measured by micro XFI should not be used as a surrogate marker of neuroplasticity in response to the acquisition of skilled motor actions. Nanoscopic XFI could be explored in future as a means of imaging these subtle physiological changes.
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Affiliation(s)
- Mariam Alaverdashvili
- Neuroscience Research Cluster, Saskatoon, SK, S7N 5E5, Canada; College of Pharmacy and Nutrition, Saskatoon, SK, S7N 5E5, Canada; College of Medicine, University of Saskatchewan, Saskatoon, SK, S7N 5E5, Canada.
| | - Phyllis G Paterson
- Neuroscience Research Cluster, Saskatoon, SK, S7N 5E5, Canada; College of Pharmacy and Nutrition, Saskatoon, SK, S7N 5E5, Canada
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21
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Chen X, Lu M, He X, Ma L, Birnbaumer L, Liao Y. TRPC3/6/7 Knockdown Protects the Brain from Cerebral Ischemia Injury via Astrocyte Apoptosis Inhibition and Effects on NF-кB Translocation. Mol Neurobiol 2016; 54:7555-7566. [PMID: 27826749 DOI: 10.1007/s12035-016-0227-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 10/10/2016] [Indexed: 12/23/2022]
Abstract
Ischemia contributes significantly to morbidity and mortality associated with many common neurological diseases. Calcium overload is an important mechanism of cerebral ischemia and reperfusion (I/R) injury. Despite decades of intense research, an effective beneficial treatment of stroke remains limited; few therapeutic strategies exist to combat the consequences of cerebral ischemia. Traditionally, a "neurocentric" view has dominated research in this field. Evidence is now accumulating that glial cells, especially astrocytes, play an important role in the pathophysiology of cerebral ischemia. Here, we show that transient receptor potential (TRP)C3/6/7 knockout (KO) mice subjected to an I/R procedure demonstrate ameliorated brain injury (infract size), compared to wild-type (WT) control animals. This is accompanied by reduction of NF-кB phosphorylation and an increase in protein kinase B (AKT) phosphorylation in I/R-injured brain tissues in TRPC3/6/7 KO mice. Also, the expression of pro-apoptotic protein Bcl-2 associated X (Bax) is down-regulated and that of anti-apoptotic protein Bcl-2 is upregulated in TRPC3/6/7-/- mice. Astrocytes isolated from TRPC3/6/7 KO mice and subjected to oxygen/glucose deprivation and subsequent reoxygenation (OGD-R, mimicking in vivo I/R injury) also exhibit enhanced Bcl-2 expression, reduced Bax expression, enhanced AKT phosphorylation, and reduced NF-кB phosphorylation. Furthermore, apoptotic rates of TRPC3/6/7 KO astrocytes cultured in OGD-R conditions were reduced significantly compared to WT control. These findings suggest TRPC3/6/7 channels play a detrimental role in brain I/R injury. Deletion of these channels can interfere with the activation of NF-кB (pro-apoptotic), promote activation of AKT (anti-apoptotic), and ultimately, ameliorate brain damage via inhibition of astrocyte apoptosis after cerebral ischemia/reperfusion injury.
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Affiliation(s)
- Xiaoyun Chen
- Department of Anatomy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
- Brain Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
| | - Min Lu
- Department of Anatomy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
- Brain Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
| | - Xiju He
- Department of Anatomy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
- Brain Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
| | - Le Ma
- Department of Anatomy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
- Brain Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
| | - Lutz Birnbaumer
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC, 27709, USA
- Institute of Biomedical Research (BIOMED), Catholic University of Argentina, C1107AFF, Buenos Aires, Argentina
| | - Yanhong Liao
- Department of Anatomy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China.
- Brain Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China.
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Slepchenko KG, Lu Q, Li YV. Zinc wave during the treatment of hypoxia is required for initial reactive oxygen species activation in mitochondria. INTERNATIONAL JOURNAL OF PHYSIOLOGY, PATHOPHYSIOLOGY AND PHARMACOLOGY 2016; 8:44-51. [PMID: 27186322 PMCID: PMC4859878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 02/09/2016] [Indexed: 06/05/2023]
Abstract
Mitochondrial reactive oxygen species (ROS) are known to accumulate during chemical hypoxia, causing adverse effects on cell function and survival. Recent studies show important role zinc accumulation plays in dysfunction associated with hypoxia. It is well known that ROS accumulation also plays a major role in cellular damage by hypoxia. In this study, fluorescent imaging and pharmacological methods were used in live HeLa cells to determine role of zinc in initial ROS accumulation in mitochondria during chemical hypoxia (oxygen glucose depravation with 4 mM sodium dithionite). Accumulation of both was observed as a very rapid phenomenon with initial rapid zinc increase (zinc wave) within 60 seconds of hypoxia onset and ROS increase within 4.5 minutes. Zinc chelation with TPEN removed the initial zinc wave which in turn abolished ROS accumulation. Influx of exogenous zinc induced rapid ROS accumulation. Inhibition of NADPH oxidase with apocynin, a NADPH oxidase inhibitor, showed significant and prolonged reduction in zinc induced ROS accumulation. We proposed a novel mechanism of intracellular zinc increase that activates NADPH oxidase which in turn triggers mitochondrial ROS production.
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Affiliation(s)
- Kira G Slepchenko
- Department of Biomedical Science and Biological Science, Ohio Heritage College of Osteopathic Medicine, Ohio University Athens Ohio, USA
| | - Qiping Lu
- Department of Biomedical Science and Biological Science, Ohio Heritage College of Osteopathic Medicine, Ohio University Athens Ohio, USA
| | - Yang V Li
- Department of Biomedical Science and Biological Science, Ohio Heritage College of Osteopathic Medicine, Ohio University Athens Ohio, USA
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TPEN, a Specific Zn 2+ Chelator, Inhibits Sodium Dithionite and Glucose Deprivation (SDGD)-Induced Neuronal Death by Modulating Apoptosis, Glutamate Signaling, and Voltage-Gated K + and Na + Channels. Cell Mol Neurobiol 2016; 37:235-250. [PMID: 26983717 DOI: 10.1007/s10571-016-0364-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 03/08/2016] [Indexed: 02/06/2023]
Abstract
Hypoxia-ischemia-induced neuronal death is an important pathophysiological process that accompanies ischemic stroke and represents a major challenge in preventing ischemic stroke. To elucidate factors related to and a potential preventative mechanism of hypoxia-ischemia-induced neuronal death, primary neurons were exposed to sodium dithionite and glucose deprivation (SDGD) to mimic hypoxic-ischemic conditions. The effects of N,N,N',N'-tetrakis (2-pyridylmethyl) ethylenediamine (TPEN), a specific Zn2+-chelating agent, on SDGD-induced neuronal death, glutamate signaling (including the free glutamate concentration and expression of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptor (GluR2) and N-methyl-D-aspartate (NMDA) receptor subunits (NR2B), and voltage-dependent K+ and Na+ channel currents were also investigated. Our results demonstrated that TPEN significantly suppressed increases in cell death, apoptosis, neuronal glutamate release into the culture medium, NR2B protein expression, and I K as well as decreased GluR2 protein expression and Na+ channel activity in primary cultured neurons exposed to SDGD. These results suggest that TPEN could inhibit SDGD-induced neuronal death by modulating apoptosis, glutamate signaling (via ligand-gated channels such as AMPA and NMDA receptors), and voltage-gated K+ and Na+ channels in neurons. Hence, Zn2+ chelation might be a promising approach for counteracting the neuronal loss caused by transient global ischemia. Moreover, TPEN could represent a potential cell-targeted therapy.
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Kim SW, Lee HK, Kim HJ, Yoon SH, Lee JK. Neuroprotective effect of ethyl pyruvate against Zn(2+) toxicity via NAD replenishment and direct Zn(2+) chelation. Neuropharmacology 2016; 105:411-419. [PMID: 26850126 DOI: 10.1016/j.neuropharm.2016.02.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Revised: 12/31/2015] [Accepted: 02/01/2016] [Indexed: 12/28/2022]
Abstract
Ethyl pyruvate (EP) is a simple aliphatic ester of pyruvic acid and has been shown to have robust protective effect in various pathological conditions. A variety of mechanisms have been reported to underlie the protective effects of EP, which include anti-inflammatory, anti-oxidative, and anti-apoptotic functions. Recently, we reported that EP suppressed high mobility group box 1 (HMGB1) release from primary microglial cells via direct Ca(2+) chelation. In the present study, we investigated whether and how EP chelates Zn(2+) in neurons when it is present at toxic levels. In cortical neurons treated with 40 μM of Zn(2+) for 24 h, both EP and pyruvate significantly suppressed neuronal cell death, although the potency of pyruvate was greater than that of EP, and that NAD replenishment contributed to the neuroprotective effects of both pyruvate and EP. However, when cortical neurons were exposed to acute treatment of Zn(2+) (400 μM, 15 min), EP, but not pyruvate, significantly suppressed neuronal death, despite the fact that NAD replenishment by EP was weaker than that by pyruvate. Spectrophotometric studies revealed that EP directly chelates Zn(2+), and this was confirmed in physiological contexts, such as, NMDA-treated primary cortical cultures and OGD-subjected hippocampal slice cultures, in which EP suppressed intracellular Zn(2+) elevation and neuronal cell death. In addition, EP markedly reduced the expressions of PARP-1 and of the NADPH oxidase subunit in Zn(2+)-treated primary cortical neurons, well known Zn(2+)-induced downstream processes. Together, these results show EP suppresses Zn(2+) induced neurotoxicity via dual functions, chelating Zn(2+) and promoting NAD replenishment.
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Affiliation(s)
- Seung-Woo Kim
- Department of Anatomy, Republic of Korea; Medical Research Center, Inha University School of Medicine Incheon, Republic of Korea
| | - Hye-Kyung Lee
- Department of Anatomy, Republic of Korea; Medical Research Center, Inha University School of Medicine Incheon, Republic of Korea
| | - Hyun-Ji Kim
- Department of Molecular Science and Technology, Ajou University, Suwon, Republic of Korea
| | - Sung-Hwa Yoon
- Department of Molecular Science and Technology, Ajou University, Suwon, Republic of Korea
| | - Ja-Kyeong Lee
- Department of Anatomy, Republic of Korea; Medical Research Center, Inha University School of Medicine Incheon, Republic of Korea.
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Karim MR, Petering DH. Newport Green, a fluorescent sensor of weakly bound cellular Zn(2+): competition with proteome for Zn(2). Metallomics 2016; 8:201-10. [PMID: 26694316 PMCID: PMC4777312 DOI: 10.1039/c5mt00167f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Newport Green (NPG) is a recognized sensor of cellular Zn(2+) that displays fluorescence enhancement upon binding to Zn(2+). Because of its modest affinity for Zn(2+), the extent of its capacity to bind cellular Zn(2+) is unclear. The present study investigated the range of reactivity of NPG(ESTER) with cells, isolated (Zn)-proteome, and model Zn-proteins. The sensor accumulated in pig kidney LLC-PK1 cells and was slowly (>40 min) hydrolyzed to the fluorescent, acid form, NPG(ACID). The powerful, cell permeant Zn(2+) chelator, N,N,N',N'-tetrakis(2-pyridylmethyl)-ethane-1,2-diamine (TPEN) failed to quench the growing fluorescence emission, indicating that Zn-NPG(ACID) had not formed and NPG-Zn-protein adduct species probably were not present. Furthermore, NPG(ACID) did not bind to Zn-carbonic anhydrase or Zn-alcohol dehydrogenase, two proteins that form adducts with some other sensors. Strikingly, most of the NPG(ACID) that had been converted from NPG(ESTER) was detected in the extracellular medium not the cells. As a result, after cells were incubated with NPG(ESTER) and then Zn-pyrithione to raise the internal concentration of mobile Zn(2+), Zn-NPG(ACID) was only observed in the external medium. Residual cellular NPG(ACID) was unable to bind extra intracellular Zn(2+) delivered by pyrithione. Proteome isolated from the sonicated cell supernatant was also unreactive with NPG(ACID). Titration of proteome or glutathione with Zn(2+) in the presence of NPG(ACID) revealed that NPG(ACID) only weakly competes for mobile Zn(2+) in the presence of these cellular components. In addition, when proteomic Zn(2+) was released by a nitric oxide donor or N-ethyl-maleimide, little Zn(2+) was detected by NPG(ACID). However, exposure to nitric oxide independently enhanced the fluorescence properties of NPG(ACID). Thus, the biochemical properties of NPG related to cellular Zn(2+) chelation deepen the question of how it functions as a Zn(2+) sensor.
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Affiliation(s)
- Mohammad Rezaul Karim
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA.
| | - David H Petering
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA.
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Stork CJ, Li YV. Elevated Cytoplasmic Free Zinc and Increased Reactive Oxygen Species Generation in the Context of Brain Injury. ACTA NEUROCHIRURGICA SUPPLEMENT 2016; 121:347-53. [DOI: 10.1007/978-3-319-18497-5_60] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Leal SS, Cristóvão JS, Biesemeier A, Cardoso I, Gomes CM. Aberrant zinc binding to immature conformers of metal-free copper-zinc superoxide dismutase triggers amorphous aggregation. Metallomics 2015; 7:333-46. [PMID: 25554447 DOI: 10.1039/c4mt00278d] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Superoxide dismutase 1 (SOD1) is a Cu/Zn metalloenzyme that aggregates in amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disorder. Correct metal insertion during SOD1 biosynthesis is critical to prevent misfolding; however Zn(2+) can bind to the copper-site leading to an aberrantly metallated protein. These effects of Zn(2+) misligation on SOD1 aggregation remain to be explored, even though Zn(2+) levels are upregulated in ALS motor neurons. Here we use complementary biophysical methods to investigate Zn(2+) binding and its effects on the aggregation of three immature metal-free SOD1 conformers that represent biogenesis intermediates: dimeric, monomeric and reduced monomeric SOD1. Using isothermal titration calorimetry we determined that Zn(2+) binds to all conformers both at the zinc- as well as to the copper-site; however Zn(2+) binding mechanisms to the zinc-site have distinct characteristics across immature conformers. We show that this 'zinc overload' of immature SOD1 promotes intermolecular interactions, as evidenced by dynamic light scattering and ThT fluorescence kinetic studies. Analysis of aged zinc-induced aggregates by energy-dispersive X-ray and electron energy-loss spectroscopy shows that aggregates integrate some Zn(2+). In addition, electron diffraction analysis identifies nano-scaled crystalline materials and amyloid fibril-like reflections. Transmission electron microscopy reveals that Zn(2+) diverts the SOD1 aggregation pathway from fibrils to amorphous aggregate, and electrophoretic analysis evidences an increase in insoluble materials. Overall, we provide evidence that aberrant zinc coordination to immature conformers broadens the population of SOD1 misfolded species at early aggregation stages and provide evidence for a high structural polymorphism and heterogeneity of SOD1 aggregates.
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Affiliation(s)
- Sónia S Leal
- Instituto Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.
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Relationship between Zinc (Zn (2+) ) and Glutamate Receptors in the Processes Underlying Neurodegeneration. Neural Plast 2015; 2015:591563. [PMID: 26106488 PMCID: PMC4461779 DOI: 10.1155/2015/591563] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 05/13/2015] [Indexed: 12/25/2022] Open
Abstract
The results from numerous studies have shown that an imbalance between particular neurotransmitters may lead to brain circuit dysfunction and development of many pathological states. The significance of glutamate pathways for the functioning of the nervous system is equivocal. On the one hand, glutamate transmission is necessary for neuroplasticity, synaptogenesis, or cell survival, but on the other hand an excessive and long-lasting increased level of glutamate in the synapse may lead to cell death. Under clinical conditions, hyperactivity of the glutamate system is associated with ischemia, epilepsy, and neurodegenerative diseases such as Alzheimer's, Huntington's, and many others. The achievement of glutamate activity in the physiological range requires efficient control by endogenous regulatory factors. Due to the fact that the free pool of ion Zn(2+) is a cotransmitter in some glutamate neurons; the role of this element in the pathophysiology of a neurodegenerative diseases has been intensively studied. There is a lot of evidence for Zn(2+) dyshomeostasis and glutamate system abnormalities in ischemic and neurodegenerative disorders. However, the precise interaction between Zn(2+) regulative function and the glutamate system is still not fully understood. This review describes the relationship between Zn(2+) and glutamate dependent signaling pathways under selected pathological central nervous system (CNS) conditions.
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Zinc preconditioning protects against neuronal apoptosis through the mitogen-activated protein kinase-mediated induction of heat shock protein 70. Biochem Biophys Res Commun 2015; 459:220-226. [PMID: 25712525 DOI: 10.1016/j.bbrc.2015.02.068] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 02/16/2015] [Indexed: 02/01/2023]
Abstract
During brain ischemic preconditioning (PC), mild bursts of ischemia render neurons resistant to subsequent strong ischemic injuries. Previously, we reported that zinc plays a key role in PC-induced neuroprotection in vitro and in vivo. Zinc-triggered p75(NTR) induction transiently activates caspase-3, which cleaves poly(ADP-ribose) polymerase-1 (PARP-1). Subsequently, the PARP-1 over-activation-induced depletion of nicotinamide adenine dinucleotide (NAD(+))/adenosine triphosphate (ATP) after exposures to lethal doses of zinc or N-methyl-D-aspartate is significantly attenuated in cortical neuronal cultures. In the present study, zinc-mediated preconditioning (Zn PC) reduced apoptotic neuronal death that was caused by N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), etoposide, or staurosporine in mouse cortical cells. We focused on heat shock protein 70 (HSP70) because NAD(+)/ATP depletion does not directly cause apoptosis, and HSP70 can inhibit the activation of caspase-9 or caspase-3 by preventing apoptosome formation or cytochrome C release. Zn PC-mediated HSP70 induction was required for neuroprotection against neuronal apoptosis, and geldanamycin-induced HSP70 induction sufficiently blocked neuronal apoptotic cell death. Furthermore, Zn PC-mediated HSP70 induction was blocked by chemical inhibitors of extracellular signal-regulated kinase (ERK) or p38 mitogen-activated protein kinase (MAPK) signaling, but not c-Jun N-terminal protein kinase. Similarly, neuroprotection by Zn PC against TPEN-induced apoptosis was almost completely reversed by the blockade of ERK or p38 MAPK signaling. Our findings suggest that the ERK- or p38 MAPK-mediated induction of HSP70 plays a key role in inhibiting caspase-3 activation during Zn PC.
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Inoue K, O'Bryant Z, Xiong ZG. Zinc-permeable ion channels: effects on intracellular zinc dynamics and potential physiological/pathophysiological significance. Curr Med Chem 2015; 22:1248-57. [PMID: 25666796 PMCID: PMC4363167 DOI: 10.2174/0929867322666150209153750] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/14/2014] [Accepted: 02/02/2015] [Indexed: 02/08/2023]
Abstract
Zinc (Zn(2+)) is one of the most important trace metals in the body. It is necessary for the normal function of a large number of protein s including enzymes and transcription factors. While extracellular fluid may contain up to micromolar Zn(2+), intracellular Zn(2+) concentration is generally maintained at a subnanomolar level; this steep gradient across the cell membrane is primarily attributable to Zn(2+) extrusion by Zn(2+) transporting systems. Interestingly, systematic investigation has revealed that activities, previously believed to be dependent on calcium (Ca(2+)), may be partially mediated by Zn(2+). This is also supported by new findings that some Ca(2+)-permeable channels such as voltage-dependent calcium channels (VDCCs), N-methyl-D-aspartate receptors (NMDA), and amino-3- hydroxy-5-methyl-4-isoxazolepropionate receptors (AMPA-Rs) are also permeable to Zn(2+). Thus, the importance of Zn(2+) in physiological and pathophysiological processes is now more widely appreciated. In this review, we describe Zn(2+)- permeable membrane molecules, especially Zn(2+)-permeable ion channels, in intracellular Zn(2+)dynamics and Zn(2+) mediated physiology/pathophysiology.
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Affiliation(s)
- Koichi Inoue
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, USA.
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TRPM2 channel deficiency prevents delayed cytosolic Zn2+ accumulation and CA1 pyramidal neuronal death after transient global ischemia. Cell Death Dis 2014; 5:e1541. [PMID: 25429618 PMCID: PMC4260752 DOI: 10.1038/cddis.2014.494] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 10/02/2014] [Accepted: 10/16/2014] [Indexed: 11/09/2022]
Abstract
Transient ischemia is a leading cause of cognitive dysfunction. Postischemic ROS generation and an increase in the cytosolic Zn2+ level ([Zn2+]c) are critical in delayed CA1 pyramidal neuronal death, but the underlying mechanisms are not fully understood. Here we investigated the role of ROS-sensitive TRPM2 (transient receptor potential melastatin-related 2) channel. Using in vivo and in vitro models of ischemia–reperfusion, we showed that genetic knockout of TRPM2 strongly prohibited the delayed increase in the [Zn2+]c, ROS generation, CA1 pyramidal neuronal death and postischemic memory impairment. Time-lapse imaging revealed that TRPM2 deficiency had no effect on the ischemia-induced increase in the [Zn2+]c but abolished the cytosolic Zn2+ accumulation during reperfusion as well as ROS-elicited increases in the [Zn2+]c. These results provide the first evidence to show a critical role for TRPM2 channel activation during reperfusion in the delayed increase in the [Zn2+]c and CA1 pyramidal neuronal death and identify TRPM2 as a key molecule signaling ROS generation to postischemic brain injury.
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32
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Malairaman U, Dandapani K, Katyal A. Effect of Ca2EDTA on zinc mediated inflammation and neuronal apoptosis in hippocampus of an in vivo mouse model of hypobaric hypoxia. PLoS One 2014; 9:e110253. [PMID: 25340757 PMCID: PMC4207758 DOI: 10.1371/journal.pone.0110253] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 09/16/2014] [Indexed: 12/17/2022] Open
Abstract
Background Calcium overload has been implicated as a critical event in glutamate excitotoxicity associated neurodegeneration. Recently, zinc accumulation and its neurotoxic role similar to calcium has been proposed. Earlier, we reported that free chelatable zinc released during hypobaric hypoxia mediates neuronal damage and memory impairment. The molecular mechanism behind hypobaric hypoxia mediated neuronal damage is obscure. The role of free zinc in such neuropathological condition has not been elucidated. In the present study, we investigated the underlying role of free chelatable zinc in hypobaric hypoxia-induced neuronal inflammation and apoptosis resulting in hippocampal damage. Methods Adult male Balb/c mice were exposed to hypobaric hypoxia and treated with saline or Ca2EDTA (1.25 mM/kg i.p) daily for four days. The effects of Ca2EDTA on apoptosis (caspases activity and DNA fragmentation), pro-inflammatory markers (iNOS, TNF-α and COX-2), NADPH oxidase activity, poly(ADP ribose) polymerase (PARP) activity and expressions of Bax, Bcl-2, HIF-1α, metallothionein-3, ZnT-1 and ZIP-6 were examined in the hippocampal region of brain. Results Hypobaric hypoxia resulted in increased expression of metallothionein-3 and zinc transporters (ZnT-1 and ZIP-6). Hypobaric hypoxia elicited an oxidative stress and inflammatory response characterized by elevated NADPH oxidase activity and up-regulation of iNOS, COX-2 and TNF-α. Furthermore, hypobaric hypoxia induced HIF-1α protein expression, PARP activation and apoptosis in the hippocampus. Administration of Ca2EDTA significantly attenuated the hypobaric hypoxia induced oxidative stress, inflammation and apoptosis in the hippocampus. Conclusion We propose that hypobaric hypoxia/reperfusion instigates free chelatable zinc imbalance in brain associated with neuroinflammation and neuronal apoptosis. Therefore, zinc chelating strategies which block zinc mediated neuronal damage linked with cerebral hypoxia and other neurodegenerative conditions can be designed in future.
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Affiliation(s)
- Udayabanu Malairaman
- Dr.B.R.Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | - Kumaran Dandapani
- Dr.B.R.Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | - Anju Katyal
- Dr.B.R.Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
- * E-mail:
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Alaverdashvili M, Hackett MJ, Pickering IJ, Paterson PG. Laminar-specific distribution of zinc: evidence for presence of layer IV in forelimb motor cortex in the rat. Neuroimage 2014; 103:502-510. [PMID: 25192655 DOI: 10.1016/j.neuroimage.2014.08.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 06/29/2014] [Accepted: 08/24/2014] [Indexed: 10/24/2022] Open
Abstract
The rat is the most widely studied pre-clinical model system of various neurological and neurodegenerative disorders affecting hand function. Although brain injury to the forelimb region of the motor cortex in rats mostly induces behavioral abnormalities in motor control of hand movements, behavioral deficits in the sensory-motor domain are also observed. This questions the prevailing view that cortical layer IV, a recipient of sensory information from the thalamus, is absent in rat motor cortex. Because zinc-containing neurons are generally not found in pathways that run from the thalamus, an absence of zinc (Zn) in a cortical layer would be suggestive of sensory input from the thalamus. To test this hypothesis, we used synchrotron micro X-ray fluorescence imaging to measure Zn distribution across cortical layers. Zn maps revealed a heterogeneous layered Zn distribution in primary and secondary motor cortices of the forelimb region in the adult rat. Two wider bands with elevated Zn content were separated by a narrow band having reduced Zn content, and this was evident in two rat strains. The Zn distribution pattern was comparable to that in sensorimotor cortex, which is known to contain a well demarcated layer IV. Juxtaposition of Zn maps and the images of brain stained for Nissl bodies revealed a "Zn valley" in primary motor cortex, apparently starting at the ventral border of pyramidal layer III and ending at the close vicinity of layer V. This finding indicates the presence of a conspicuous cortical layer between layers III and V, i.e. layer IV, the presence of which previously has been disputed. The results have implications for the use of rat models to investigate human brain function and neuropathology, such as after stroke. The presence of layer IV in the forelimb region of the motor cortex suggests that therapeutic interventions used in rat models of motor cortex injury should target functional abnormalities in both motor and sensory domains. The finding is also critical for future investigation of the biochemical mechanisms through which therapeutic interventions can enhance neural plasticity, particularly through Zn dependent pathways.
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Affiliation(s)
- Mariam Alaverdashvili
- Neuroscience Research Group, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada; College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada.
| | - Mark J Hackett
- Neuroscience Research Group, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada; Department of Geological Sciences, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Ingrid J Pickering
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Phyllis G Paterson
- Neuroscience Research Group, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada; College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
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Medvedeva YV, Weiss JH. Intramitochondrial Zn2+ accumulation via the Ca2+ uniporter contributes to acute ischemic neurodegeneration. Neurobiol Dis 2014; 68:137-44. [PMID: 24787898 DOI: 10.1016/j.nbd.2014.04.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 04/02/2014] [Accepted: 04/21/2014] [Indexed: 01/02/2023] Open
Abstract
Ca(2+) and Zn(2+) have both been implicated in the induction of acute ischemic neurodegeneration. We recently examined changes in intracellular Zn(2+) and Ca(2+) in CA1 pyramidal neurons subjected to oxygen glucose deprivation (OGD), and found that Zn(2+) rises precede and contribute to the onset of terminal Ca(2+) rises ("Ca(2+) deregulation"), which are causatively linked to a lethal loss of membrane integrity. The present study seeks to examine the specific role of intramitochondrial Zn(2+) accumulation in ischemic injury, using blockers of the mitochondrial Ca(2+) uniporter (MCU), through which both Zn(2+) and Ca(2+) appear able to enter the mitochondrial matrix. In physiological extracellular Ca(2+), treatment with the MCU blocker, Ruthenium Red (RR), accelerated the Ca(2+) deregulation, most likely by disrupting mitochondrial Ca(2+) buffering and thus accelerating the lethal cytosolic Ca(2+) overload. However, when intracellular Ca(2+) overload was slowed, either by adding blockers of major Ca(2+) entry channels or by lowering the concentration of Ca(2+) in the extracellular buffer, Ca(2+) deregulation was delayed, and under these conditions either Zn(2+) chelation or MCU blockade resulted in similar further delays of the Ca(2+) deregulation. In parallel studies using the reactive oxygen species (ROS) indicator, hydroethidine, lowering Ca(2+) surprisingly accelerated OGD induced ROS generation, and in these low Ca(2+) conditions, either Zn(2+) chelation or MCU block slowed the ROS generation. These studies suggest that, during acute ischemia, Zn(2+) entry into mitochondria via the MCU induces mitochondrial dysfunction (including ROS generation) that occurs upstream of, and contributes to the terminal Ca(2+) deregulation.
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Affiliation(s)
- Yuliya V Medvedeva
- Department of Neurology, University of California, Irvine, Irvine, CA 92697, USA; Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92697, USA.
| | - John H Weiss
- Department of Neurology, University of California, Irvine, Irvine, CA 92697, USA; Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92697, USA.
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Mechanisms of rapid reactive oxygen species generation in response to cytosolic Ca2+ or Zn2+ loads in cortical neurons. PLoS One 2013; 8:e83347. [PMID: 24340096 PMCID: PMC3858366 DOI: 10.1371/journal.pone.0083347] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Accepted: 11/01/2013] [Indexed: 12/16/2022] Open
Abstract
Excessive “excitotoxic” accumulation of Ca2+ and Zn2+ within neurons contributes to neurodegeneration in pathological conditions including ischemia. Putative early targets of these ions, both of which are linked to increased reactive oxygen species (ROS) generation, are mitochondria and the cytosolic enzyme, NADPH oxidase (NOX). The present study uses primary cortical neuronal cultures to examine respective contributions of mitochondria and NOX to ROS generation in response to Ca2+ or Zn2+ loading. Induction of rapid cytosolic accumulation of either Ca2+ (via NMDA exposure) or Zn2+ (via Zn2+/Pyrithione exposure in 0 Ca2+) caused sharp cytosolic rises in these ions, as well as a strong and rapid increase in ROS generation. Inhibition of NOX activation significantly reduced the Ca2+-induced ROS production with little effect on the Zn2+- triggered ROS generation. Conversely, dissipation of the mitochondrial electrochemical gradient increased the cytosolic Ca2+ or Zn2+ rises caused by these exposures, consistent with inhibition of mitochondrial uptake of these ions. However, such disruption of mitochondrial function markedly suppressed the Zn2+-triggered ROS, while partially attenuating the Ca2+-triggered ROS. Furthermore, block of the mitochondrial Ca2+ uniporter (MCU), through which Zn2+ as well as Ca2+ can enter the mitochondrial matrix, substantially diminished Zn2+ triggered ROS production, suggesting that the ROS generation occurs specifically in response to Zn2+ entry into mitochondria. Finally, in the presence of the sulfhydryl-oxidizing agent 2,2'-dithiodipyridine, which impairs Zn2+ binding to cytosolic metalloproteins, far lower Zn2+ exposures were able to induce mitochondrial Zn2+ uptake and consequent ROS generation. Thus, whereas rapid acute accumulation of Zn2+ and Ca2+ each can trigger injurious ROS generation, Zn2+ entry into mitochondria via the MCU may do so with particular potency. This may be of particular relevance to conditions like ischemia in which cytosolic Zn2+ buffering is impaired due to acidosis and oxidative stress.
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Hyrc KL, Minta A, Escamilla PR, Chan PPL, Meshik XA, Goldberg MP. Synthesis and properties of Asante Calcium Red--a novel family of long excitation wavelength calcium indicators. Cell Calcium 2013; 54:320-33. [PMID: 24017967 DOI: 10.1016/j.ceca.2013.08.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 07/29/2013] [Accepted: 08/01/2013] [Indexed: 10/26/2022]
Abstract
Although many synthetic calcium indicators are available, a search for compounds with improved characteristics continues. Here, we describe the synthesis and properties of Asante Calcium Red-1 (ACR-1) and its low affinity derivative (ACR-1-LA) created by linking BAPTA to seminaphthofluorescein. The indicators combine a visible light (450-540 nm) excitation with deep-red fluorescence (640 nm). Upon Ca2+ binding, the indicators raise their fluorescence with longer excitation wavelengths producing higher responses. Although the changes occur without any spectral shifts, it is possible to ratio Ca(2+)-dependent (640 nm) and quasi-independent (530 nm) emission when using visible (< 490 nm) or multiphoton (∼780 nm) excitation. Therefore, both probes can be used as single wavelength or, less dynamic, ratiometric indicators. Long indicator emission might allow easy [Ca2+]i measurement in GFP expressing cells. The indicators bind Ca2+ with either high (Kd = 0.49 ± 0.07 μM; ACR-1) or low affinity (Kd = 6.65 ± 0.13 μM; ACR-1-LA). Chelating Zn2+ (Kd = 0.38 ± 0.02 nM) or Mg2+ (Kd∼5mM) slightly raises and binding Co2+ quenches dye fluorescence. New indicators are somewhat pH-sensitive (pKa = 6.31 ± 0.07), but fairly resistant to bleaching. The probes are rather dim, which combined with low AM ester loading efficiency, might complicate in situ imaging. Despite potential drawbacks, ACR-1 and ACR-1-LA are promising new calcium indicators.
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Affiliation(s)
- Krzysztof L Hyrc
- The Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO 63110, USA; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO 63110, USA; Alafi Neuroimaging Laboratory, Washington University School of Medicine, St. Louis, MO 63110, USA.
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Convergent Ca2+ and Zn2+ signaling regulates apoptotic Kv2.1 K+ currents. Proc Natl Acad Sci U S A 2013; 110:13988-93. [PMID: 23918396 DOI: 10.1073/pnas.1306238110] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
A simultaneous increase in cytosolic Zn(2+) and Ca(2+) accompanies the initiation of neuronal cell death signaling cascades. However, the molecular convergence points of cellular processes activated by these cations are poorly understood. Here, we show that Ca(2+)-dependent activation of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is required for a cell death-enabling process previously shown to also depend on Zn(2+). We have reported that oxidant-induced intraneuronal Zn(2+) liberation triggers a syntaxin-dependent incorporation of Kv2.1 voltage-gated potassium channels into the plasma membrane. This channel insertion can be detected as a marked enhancement of delayed rectifier K(+) currents in voltage clamp measurements observed at least 3 h following a short exposure to an apoptogenic stimulus. This current increase is the process responsible for the cytoplasmic loss of K(+) that enables protease and nuclease activation during apoptosis. In the present study, we demonstrate that an oxidative stimulus also promotes intracellular Ca(2+) release and activation of CaMKII, which, in turn, modulates the ability of syntaxin to interact with Kv2.1. Pharmacological or molecular inhibition of CaMKII prevents the K(+) current enhancement observed following oxidative injury and, importantly, significantly increases neuronal viability. These findings reveal a previously unrecognized cooperative convergence of Ca(2+)- and Zn(2+)-mediated injurious signaling pathways, providing a potentially unique target for therapeutic intervention in neurodegenerative conditions associated with oxidative stress.
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Yu X, Li YV. Neuroprotective effect of zinc chelator DEDTC in a zebrafish (Danio rerio) Model of Hypoxic Brain Injury. Zebrafish 2013; 10:30-5. [PMID: 23461417 DOI: 10.1089/zeb.2012.0777] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A study was conducted using zebrafish as a model of hypoxic brain injury to investigate the potential neuroprotective effects of zinc (Zn(2+)) chelation. The accumulation of intracellular Zn(2+) is a significant causal factor of the neuronal injury, and has been implicated in cell death followed by ischemic stroke. In this study, the zebrafish was placed in the hypoxia chamber with an extremely low level of dissolved oxygen (less than 0.8 mg/L), which is similar to the conditions in a complete global ischemic stroke. Approximately 50% of zebrafish died after a short period (≈11 min) of hypoxic treatment, suggesting that this is a responsive model system for use in evaluating treatments for hypoxic brain damage. The application of DEDTC reduced intracellular Zn(2+) accumulation and produced a concentration-dependent effect by increasing the survival rate of zebrafish. Zn(2+) chelation also enhanced zebrafish tolerance for hypoxia. When the brain damages were evaluated with TTC staining, the zebrafish that were treated with DEDTC in hypoxic treatment yielded the improvement of TTC staining that was similar to the healthy zebrafish brain. The results support that rising intracellular Zn(2+) plays a critical role in the neuronal damages, and demonstrate the protective effects of Zn(2+) chelation in hypoxic-ischemic brain injury in zebrafish.
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Affiliation(s)
- Xinge Yu
- Program in Biological Sciences, Ohio University, Athens, OH 45701, USA
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Hyman LM, Franz KJ. Probing oxidative stress: Small molecule fluorescent sensors of metal ions, reactive oxygen species, and thiols. Coord Chem Rev 2012; 256:2333-2356. [PMID: 23440254 PMCID: PMC3579673 DOI: 10.1016/j.ccr.2012.03.009] [Citation(s) in RCA: 231] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Oxidative stress is a common feature shared by many diseases, including neurodegenerative diseases. Factors that contribute to cellular oxidative stress include elevated levels of reactive oxygen species, diminished availability of detoxifying thiols, and the misregulation of metal ions (both redox-active iron and copper as well as non-redox active calcium and zinc). Deciphering how each of these components interacts to contribute to oxidative stress presents an interesting challenge. Fluorescent sensors can be powerful tools for detecting specific analytes within a complicated cellular environment. Reviewed here are several classes of small molecule fluorescent sensors designed to detect several molecular participants of oxidative stress. We focus our review on describing the design, function and application of probes to detect metal cations, reactive oxygen species, and intracellular thiol-containing compounds. In addition, we highlight the intricacies and complications that are often faced in sensor design and implementation.
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Affiliation(s)
- Lynne M. Hyman
- Department of Chemistry, Duke University, Durham, NC 27708, USA
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40
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McCranor BJ, Bozym RA, Vitolo MI, Fierke CA, Bambrick L, Polster BM, Fiskum G, Thompson RB. Quantitative imaging of mitochondrial and cytosolic free zinc levels in an in vitro model of ischemia/reperfusion. J Bioenerg Biomembr 2012; 44:253-63. [PMID: 22430627 DOI: 10.1007/s10863-012-9427-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Accepted: 12/17/2011] [Indexed: 01/25/2023]
Abstract
The role of zinc ion in cytotoxicity following ischemic stroke, prolonged status epilepticus, and traumatic brain injury remains controversial, but likely is the result of mitochondrial dysfunction. We describe an excitation ratiometric fluorescence biosensor based on human carbonic anhydrase II variants expressed in the mitochondrial matrix, permitting free zinc levels to be quantitatively imaged therein. We observed an average mitochondrial matrix free zinc concentration of 0.2 pM in the PC12 rat pheochromacytoma cell culture line. Cytoplasmic and mitochondrial free zinc levels were imaged in a cellular oxygen glucose deprivation (OGD) model of ischemia/reperfusion. We observed a significant increase in mitochondrial zinc 1 h following 3 h OGD, at a time point when cytosolic zinc levels were depressed. Following the increase, mitochondrial zinc levels returned to physiological levels, while cytosolic zinc increased gradually over a 24 h time period in viable cells. The increase in intramitochondrial zinc observed during reoxygenation after OGD may contribute to bioenergetic dysfunction and cell death that occurs with both in vitro and in vivo models of reperfusion.
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Affiliation(s)
- Bryan J McCranor
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene St., Baltimore, MD 21201, USA
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41
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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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Udayabanu M, Kumaran D, Katyal A. Free chelatable zinc modulates the cholinergic function during hypobaric hypoxia-induced neuronal damage: an in vivo study. Neuroscience 2012; 202:434-45. [DOI: 10.1016/j.neuroscience.2011.11.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 11/08/2011] [Accepted: 11/08/2011] [Indexed: 10/15/2022]
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43
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Mechanisms underlying interaction of zinc, lead, and cobalt with nonspecific permeability pores in the mitochondrial membranes. NEUROPHYSIOLOGY+ 2011. [DOI: 10.1007/s11062-011-9219-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Aras MA, Aizenman E. Redox regulation of intracellular zinc: molecular signaling in the life and death of neurons. Antioxid Redox Signal 2011; 15:2249-63. [PMID: 20849376 PMCID: PMC3166180 DOI: 10.1089/ars.2010.3607] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Zn(2+) has emerged as a major regulator of neuronal physiology, as well as an important signaling agent in neural injury. The intracellular concentration of this metal is tightly regulated through the actions of Zn(2+) transporters and the thiol-rich metal binding protein metallothionein, closely linking the redox status of the cell to cellular availability of Zn(2+). Accordingly, oxidative and nitrosative stress during ischemic injury leads to an accumulation of neuronal free Zn(2+) and the activation of several downstream cell death processes. While this Zn(2+) rise is an established signaling event in neuronal cell death, recent evidence suggests that a transient, sublethal accumulation of free Zn(2+) can also play a critical role in neuroprotective pathways activated during ischemic preconditioning. Thus, redox-sensitive proteins, like metallothioneins, may play a critical role in determining neuronal cell fate by regulating the localization and concentration of intracellular free Zn(2+).
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Affiliation(s)
- Mandar A Aras
- Department of Neurobiology, University of Pittsburgh School of Medicine, 3500 Terrace St., Pittsburgh, PA 15261, USA.
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Kim AM, Bernhardt ML, Kong BY, Ahn RW, Vogt S, Woodruff TK, O’Halloran TV. Zinc sparks are triggered by fertilization and facilitate cell cycle resumption in mammalian eggs. ACS Chem Biol 2011; 6:716-23. [PMID: 21526836 DOI: 10.1021/cb200084y] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In last few hours of maturation, the mouse oocyte takes up over twenty billion zinc atoms and arrests after the first meiotic division, until fertilization or pharmacological intervention stimulates cell cycle progression toward a new embryo. Using chemical and physical probes, we show that fertilization of the mature, zinc-enriched egg triggers the ejection of zinc into the extracellular milieu in a series of coordinated events termed zinc sparks. These events immediately follow the well-established series of calcium oscillations within the activated egg and are evolutionarily conserved in several mammalian species, including rodents and nonhuman primates. Functionally, the zinc sparks mediate a decrease in intracellular zinc content that is necessary for continued cell cycle progression, as increasing zinc levels within the activated egg results in the reestablishment of cell cycle arrest at metaphase. The mammalian egg thus uses a zinc-dependent switch mechanism to toggle between metaphase arrest and resumption of the meiotic cell cycle at the initiation of embryonic development.
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Affiliation(s)
- Alison M. Kim
- Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, 250 E. Superior St., Suite 3-2303, Chicago, Illinois 60611, United States
| | - Miranda L. Bernhardt
- Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, 250 E. Superior St., Suite 3-2303, Chicago, Illinois 60611, United States
| | - Betty Y. Kong
- Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, 250 E. Superior St., Suite 3-2303, Chicago, Illinois 60611, United States
| | | | - Stefan Vogt
- X-ray Science Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, Illinois 60439, United States
| | - Teresa K. Woodruff
- Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, 250 E. Superior St., Suite 3-2303, Chicago, Illinois 60611, United States
- Department of Molecular Biosciences, Northwestern University, 2205 Tech Drive, Hogan 2-100, Evanston, Illinois 60208, United States
| | - Thomas V. O’Halloran
- Department of Molecular Biosciences, Northwestern University, 2205 Tech Drive, Hogan 2-100, Evanston, Illinois 60208, United States
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Shuttleworth CW, Weiss JH. Zinc: new clues to diverse roles in brain ischemia. Trends Pharmacol Sci 2011; 32:480-6. [PMID: 21621864 DOI: 10.1016/j.tips.2011.04.001] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 04/19/2011] [Accepted: 04/21/2011] [Indexed: 12/22/2022]
Abstract
Cerebral ischemia is a leading cause of morbidity and mortality, reflecting the extraordinary sensitivity of the brain to a brief loss of blood flow. A significant goal has been to identify pathways of neuronal injury that are selectively activated after stroke and may be amenable to drug therapy. An important advance was made nearly 25 years ago when Ca(2+) overload was implicated as a critical link between glutamate excitotoxicity and ischemic neurodegeneration. However, early hope for effective therapies faded as glutamate-targeted trials repeatedly failed to demonstrate efficacy in humans. In a review in 2000 in this journal, we described new evidence linking a related cation, zinc (Zn(2+)), to neuronal injury, emphasizing sources and mechanisms of Zn(2+) toxicity. The current review highlights progress over the last decade, emphasizing mechanisms through which Zn(2+) ions (from multiple sources) participate together with Ca(2+) in different stages of cascades of ischemic injury.
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Affiliation(s)
- C William Shuttleworth
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque NM 87131, USA
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Lavenex P, Sugden SG, Davis RR, Gregg JP, Lavenex PB. Developmental regulation of gene expression and astrocytic processes may explain selective hippocampal vulnerability. Hippocampus 2011; 21:142-9. [PMID: 20014383 DOI: 10.1002/hipo.20730] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The hippocampus plays a central role in the brain network that is essential for memory function. Paradoxically, the hippocampus is also the brain structure that is most sensitive to hypoxic-ischemic episodes. Here, we show that the expression of genes associated with glycolysis and glutamate metabolism in astrocytes and the coverage of excitatory synapses by astrocytic processes undergo significant decreases in the CA1 field of the monkey hippocampus during postnatal development. Given the established role of astrocytes in the regulation of glutamate concentration in the synaptic cleft, our findings suggest that a developmental decrease in astrocytic processes could underlie the selective vulnerability of CA1 during hypoxic-ischemic episodes in adulthood, its decreased susceptibility to febrile seizures with age, as well as contribute to the emergence of selective, adultlike memory function.
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Affiliation(s)
- Pierre Lavenex
- Department of Psychiatry and Behavioral Sciences, UC Davis, Sacramento, California 95817, USA.
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48
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Lee SJ, Koh JY. Roles of zinc and metallothionein-3 in oxidative stress-induced lysosomal dysfunction, cell death, and autophagy in neurons and astrocytes. Mol Brain 2010; 3:30. [PMID: 20974010 PMCID: PMC2988061 DOI: 10.1186/1756-6606-3-30] [Citation(s) in RCA: 169] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Accepted: 10/26/2010] [Indexed: 12/18/2022] Open
Abstract
Zinc dyshomeostasis has been recognized as an important mechanism for cell death in acute brain injury. An increase in the level of free or histochemically reactive zinc in astrocytes and neurons is considered one of the major causes of death of these cells in ischemia and trauma. Although zinc dyshomeostasis can lead to cell death via diverse routes, the major pathway appears to involve oxidative stress. Recently, we found that a rise of zinc in autophagic vacuoles, including autolysosomes, is a prerequisite for lysosomal membrane permeabilization and cell death in cultured brain cells exposed to oxidative stress conditions. The source of zinc in this process is likely redox-sensitive zinc-binding proteins such as metallothioneins, which release zinc under oxidative conditions. Of the metallothioneins, metallothionein-3 is especially enriched in the central nervous system, but its physiologic role in this tissue is not well established. Like other metallothioneins, metallothionein-3 may function as metal detoxicant, but is also known to inhibit neurite outgrowth and, sometimes, promote neuronal death, likely by serving as a source of toxic zinc release. In addition, metallothionein-3 regulates lysosomal functions. In the absence of metallothionein-3, there are changes in lysosome-associated membrane protein-1 and -2, and reductions in certain lysosomal enzymes that result in decreased autophagic flux. This may have dual effects on cell survival. In acute oxidative injury, zinc dyshomeostasis and lysosomal membrane permeabilization are diminished in metallothionein-3 null cells, resulting in less cell death. But over the longer term, diminished lysosomal function may lead to the accumulation of abnormal proteins and cause cytotoxicity. The roles of zinc and metallothionein-3 in autophagy and/or lysosomal function have just begun to be investigated. In light of evidence that autophagy and lysosomes may play significant roles in the pathogenesis of various neurological diseases, further insight into the contribution of zinc dynamics and metallothionein-3 function may help provide ways to effectively regulate these processes in brain cells.
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Affiliation(s)
- Sook-Jeong Lee
- Neural Injury Research Center, Department of Neurology, Asan Institute for Life Science, University of Ulsan, College of Medicine, Seoul 138-736, Korea
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49
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Abstract
Calcium is an extraordinarily versatile signaling ion, encoding cellular responses to a wide variety of external stimuli. In neurons, mitochondria can accumulate enormous amounts of calcium, with the consequence that mitochondrial calcium uptake, sequestration and release play pivotal roles in orchestrating calcium-dependent responses as diverse as gene transcription and cell death. In this review, we consider the basic chemistry of calcium as a 'sticky' cation, which leads to extremely high bound/free ratios, and discuss areas of current interest or controversy. Topics addressed include methodologies for measuring local intracellular calcium, mitochondrial calcium buffering and loading capacity, mitochondrially directed spatial calcium gradients, and the role of calcium overload-dependent mitochondrial dysfunction in glutamate-evoked excitotoxic injury and neurodegeneration. Finally, we consider the relationship between delayed calcium de-regulation, the mitochondrial permeability transition and the generation of reactive oxygen species, and propose a unified view of the 'source specificity' and 'calcium overload' models of N-methyl-d-aspartate (NMDA) receptor-dependent excitotoxicity. Non-NMDA receptor mechanisms of excitotoxicity are discussed briefly.
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Affiliation(s)
- Natalia B Pivovarova
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-4477, USA
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50
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Gibon J, Tu P, Frazzini V, Sensi SL, Bouron A. The thiol-modifying agent N-ethylmaleimide elevates the cytosolic concentration of free Zn(2+) but not of Ca(2+) in murine cortical neurons. Cell Calcium 2010; 48:37-43. [PMID: 20667413 DOI: 10.1016/j.ceca.2010.06.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 06/22/2010] [Accepted: 06/22/2010] [Indexed: 10/19/2022]
Abstract
The membrane permeant alkylating agent N-ethylmaleimide (NEM) regulates numerous biological processes by reacting with thiol groups. Among other actions, NEM influences the cytosolic concentration of free Ca(2+) ([Ca(2+)]i). Depending on the cell type and the concentration used, NEM can promote the release of Ca(2+), affect its extrusion, stimulate or block its entry. However, most of these findings were obtained in experiments that employed fluorescent Ca(2+) probes and one major disadvantage of such experimental setting derives from the lack of specificity of the probes as all the so-called "Ca(2+)-sensitive" indicators also bind metals like Zn(2+) or Mn(2+) with higher affinities than Ca(2+). In this study, we examined the effects of NEM on the [Ca(2+)]i homeostasis of murine cortical neurons. We performed live-cell Ca(2+) and Zn(2+) imaging experiments using the fluorescent probes Fluo-4, FluoZin-3 and RhodZin-3 and found that NEM does not affect the neuronal [Ca(2+)]i homeostasis but specifically increases the cytosolic and mitochondrial concentration of free Zn(2+)([Zn(2+)]i). In addition, NEM triggers some neuronal loss that is prevented by anti-oxidants such as N-acetylcysteine or glutathione. NEM-induced toxicity is dependent on changes in [Zn(2+)]i levels as chelation of the cation with the cell-permeable heavy metal chelator, N,N,N'N'-tetrakis(-)[2-pyridylmethyl]-ethylenediamine (TPEN), promotes neuroprotection of cortical neurons exposed to NEM. Our data indicate that NEM affects [Zn(2+)]i but not [Ca(2+)]i homeostasis and shed new light on the physiological actions of this alkylating agent on central nervous system neurons.
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