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Ersoy B, Herzog ML, Pan W, Schilling S, Endres M, Göttert R, Kronenberg GD, Gertz K. The atypical antidepressant tianeptine confers neuroprotection against oxygen-glucose deprivation. Eur Arch Psychiatry Clin Neurosci 2024; 274:777-791. [PMID: 37653354 PMCID: PMC11127858 DOI: 10.1007/s00406-023-01685-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Accepted: 08/14/2023] [Indexed: 09/02/2023]
Abstract
Proregenerative and neuroprotective effects of antidepressants are an important topic of inquiry in neuropsychiatric research. Oxygen-glucose deprivation (OGD) mimics key aspects of ischemic injury in vitro. Here, we studied the effects of 24-h pretreatment with serotonin (5-HT), citalopram (CIT), fluoxetine (FLU), and tianeptine (TIA) on primary mouse cortical neurons subjected to transient OGD. 5-HT (50 μM) significantly enhanced neuron viability as measured by MTT assay and reduced cell death and LDH release. CIT (10 μM) and FLU (1 μM) did not increase the effects of 5-HT and neither antidepressant conferred neuroprotection in the absence of supplemental 5-HT in serum-free cell culture medium. By contrast, pre-treatment with TIA (10 μM) resulted in robust neuroprotection, even in the absence of 5-HT. Furthermore, TIA inhibited mRNA transcription of candidate genes related to cell death and hypoxia and attenuated lipid peroxidation, a hallmark of neuronal injury. Finally, deep RNA sequencing of primary neurons subjected to OGD demonstrated that OGD induces many pathways relating to cell survival, the inflammation-immune response, synaptic dysregulation and apoptosis, and that TIA pretreatment counteracted these effects of OGD. In conclusion, this study highlights the comparative strength of the 5-HT independent neuroprotective effects of TIA and identifies the molecular pathways involved.
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Affiliation(s)
- Burcu Ersoy
- Department of Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Center for Stroke Research Berlin, Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Berlin-Brandenburg School for Regenerative Therapies, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Marie-Louise Herzog
- Department of Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Center for Stroke Research Berlin, Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- DZHK (German Center for Cardiovascular Research), Partner site, Berlin, Germany
| | - Wen Pan
- Department of Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Center for Stroke Research Berlin, Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- DZHK (German Center for Cardiovascular Research), Partner site, Berlin, Germany
| | - Simone Schilling
- Department of Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Center for Stroke Research Berlin, Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- DZHK (German Center for Cardiovascular Research), Partner site, Berlin, Germany
- Berlin Institute of Health at Charité, Universitätsmedizin Berlin, Berlin, Germany
| | - Matthias Endres
- Department of Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Center for Stroke Research Berlin, Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- DZHK (German Center for Cardiovascular Research), Partner site, Berlin, Germany
- Einstein Center for Neurosciences, Charité-Universitätsmedizin Berlin, Berlin, Germany
- DZNE (German Center for Neurodegenerative Diseases), Partner site, Berlin, Germany
- DZPG (German Center for Mental Health), Partner site, Berlin, Germany
| | - Ria Göttert
- Department of Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Center for Stroke Research Berlin, Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- DZHK (German Center for Cardiovascular Research), Partner site, Berlin, Germany
| | - Golo D Kronenberg
- Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital of Psychiatry Zürich, Lenggstrasse 31, P.O. Box 363, 8032, Zurich, Switzerland
| | - Karen Gertz
- Department of Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.
- Center for Stroke Research Berlin, Department of Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.
- DZHK (German Center for Cardiovascular Research), Partner site, Berlin, Germany.
- Einstein Center for Neurosciences, Charité-Universitätsmedizin Berlin, Berlin, Germany.
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Kaur J, Mojumdar A. A mechanistic overview of spinal cord injury, oxidative DNA damage repair and neuroprotective therapies. Int J Neurosci 2023; 133:307-321. [PMID: 33789065 DOI: 10.1080/00207454.2021.1912040] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Despite substantial development in medical treatment strategies scientists are struggling to find a cure against spinal cord injury (SCI) which causes long term disability and paralysis. The prime rationale behind it is the enlargement of primary lesion due to an initial trauma to the spinal cord which spreads to the neighbouring spinal tissues It begins from the time of traumatic event happened and extends to hours and even days. It further causes series of biological and functional alterations such as inflammation, excitotoxicity and ischemia, and promotes secondary lesion to the cord which worsens the life of individuals affected by SCI. Oxidative DNA damage is a stern consequence of oxidative stress linked with secondary injury causes oxidative base alterations and strand breaks, which provokes cell death in neurons. It is implausible to stop primary damage however it is credible to halt the secondary lesion and improve the quality of the patient's life to some extent. Therefore it is crucial to understand the hidden perspectives of cell and molecular biology affecting the pathophysiology of SCI. Thus the focus of the review is to connect the missing links and shed light on the oxidative DNA damages and the functional repair mechanisms, as a consequence of the injury in neurons. The review will also probe the significance of neuroprotective strategies in the present scenario. HIGHLIGHTSSpinal cord injury, a pernicious condition, causes excitotoxicity and ischemia, ultimately leading to cell death.Oxidative DNA damage is a consequence of oxidative stress linked with secondary injury, provoking cell death in neurons.Base excision repair (BER) is one of the major repair pathways that plays a crucial role in repairing oxidative DNA damages.Neuroprotective therapies curbing SCI and boosting BER include the usage of pharmacological drugs and other approaches.
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Affiliation(s)
- Jaspreet Kaur
- Department of Neuroscience, University of Copenhagen, Copenhagen N, Denmark
| | - Aditya Mojumdar
- Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada
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Lei L, Lu Q, Ma G, Li T, Deng J, Li W. P53 protein and the diseases in central nervous system. Front Genet 2023; 13:1051395. [PMID: 36712862 PMCID: PMC9880595 DOI: 10.3389/fgene.2022.1051395] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 12/08/2022] [Indexed: 01/11/2023] Open
Abstract
P53 protein is the product of P53 gene, which is a well acknowledged tumor suppressor gene. The function of P53 and the relevant mechanisms of anti-neoplasm have raised the interest of researchers since many years ago. It is demonstrated that P53 is a basic cell cycle regulator and a strong inhibitor for versatile cancers in humans. However, most research focuses on other organs and systems instead of the central nervous system (CNS). In fact, in recent years, more and more studies have been suggesting that P53 plays a significant role in multiple CNS tumors and other diseases and disorders such as cerebral stroke and neurodegenerative diseases. In this work, we mainly reviewed the P53's relationship with CNS tumors, cerebral stroke and neurodegenerative diseases, together with the relevant mechanisms, aiming to summarize the research achievements and providing new insight to the future study on diseases in CNS.
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Affiliation(s)
- Li Lei
- The Affiliated Hospital of Kunming University of Science and Technology, The Department of Neurosurgery, The First People's Hospital of Yunnan Province, Kunming, Yunnan, China
| | - Qixiong Lu
- The Affiliated Hospital of Kunming University of Science and Technology, The Department of Neurosurgery, The First People's Hospital of Yunnan Province, Kunming, Yunnan, China
| | - Guifang Ma
- Department of Ear, Nose and Throat (ENT) and Head and Neck (HN) Surgery, The First People’s Hospital of Yunnan Province, The Affiliated Hospital of Kunming University of Science and Technology, Kunming, China
| | - Tao Li
- The Affiliated Hospital of Kunming University of Science and Technology, The Department of Neurosurgery, The First People's Hospital of Yunnan Province, Kunming, Yunnan, China
| | - Jiahong Deng
- Department of Ear, Nose and Throat (ENT) and Head and Neck (HN) Surgery, The First People’s Hospital of Yunnan Province, The Affiliated Hospital of Kunming University of Science and Technology, Kunming, China,*Correspondence: Jiahong Deng, ; Weijia Li,
| | - Weijia Li
- The Affiliated Hospital of Kunming University of Science and Technology, The Department of Neurosurgery, The First People's Hospital of Yunnan Province, Kunming, Yunnan, China,*Correspondence: Jiahong Deng, ; Weijia Li,
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Jiao M, Dong Q, Zhang Y, Lin M, Zhou W, Liu T, Yuan B, Yin H. Neuroprotection of N-benzyl Eicosapentaenamide in Neonatal Mice Following Hypoxic-Ischemic Brain Injury. Molecules 2021; 26:molecules26113108. [PMID: 34067444 PMCID: PMC8197015 DOI: 10.3390/molecules26113108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 05/18/2021] [Accepted: 05/19/2021] [Indexed: 11/26/2022] Open
Abstract
Maca (Lepidium meyenii) has emerged as a popular functional plant food because of its medicinal properties and nutritional value. Macamides, as the exclusively active ingredients found in maca, are a unique series of non-polar, long-chain fatty acid N-benzylamides with multiple bioactivities such as antifatigue characteristics and improving reproductive health. In this study, a new kind of macamide, N-benzyl eicosapentaenamide (NB-EPA), was identified from maca. We further explore its potential neuroprotective role in hypoxic–ischemic brain injury. Our findings indicated that treatment with biosynthesized NB-EPA significantly alleviates the size of cerebral infarction and improves neurobehavioral disorders after hypoxic–ischemic brain damage in neonatal mice. NB-EPA inhibited the apoptosis of neuronal cells after ischemic challenge. NB-EPA improved neuronal cell survival and proliferation through the activation of phosphorylated AKT signaling. Of note, the protective property of NB-EPA against ischemic neuronal damage was dependent on suppression of the p53–PUMA pathway. Taken together, these findings suggest that NB-EPA may represent a new neuroprotectant for newborns with hypoxic–ischemic encephalopathy.
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Affiliation(s)
- Mengya Jiao
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, China; (M.J.); (Q.D.); (Y.Z.); (W.Z.); (B.Y.)
| | - Qun Dong
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, China; (M.J.); (Q.D.); (Y.Z.); (W.Z.); (B.Y.)
- School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Yiting Zhang
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, China; (M.J.); (Q.D.); (Y.Z.); (W.Z.); (B.Y.)
- Department of Microbiology and Immunology, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Min Lin
- School of Clinical Medicine, Guangdong Pharmaceutical University, Guangzhou 510310, China;
| | - Wan Zhou
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, China; (M.J.); (Q.D.); (Y.Z.); (W.Z.); (B.Y.)
| | - Tao Liu
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, China; (M.J.); (Q.D.); (Y.Z.); (W.Z.); (B.Y.)
- Correspondence: (T.L.); (H.Y.)
| | - Baohong Yuan
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, China; (M.J.); (Q.D.); (Y.Z.); (W.Z.); (B.Y.)
- Department of Microbiology and Immunology, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Hui Yin
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, China; (M.J.); (Q.D.); (Y.Z.); (W.Z.); (B.Y.)
- Department of Microbiology and Immunology, Guangdong Pharmaceutical University, Guangzhou 510006, China
- Correspondence: (T.L.); (H.Y.)
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Lee TK, Park YE, Park CW, Kim B, Lee JC, Park JH, Lee HA, Won MH, Ahn JH. Age-dependent changes of p53 and p63 immunoreactivities in the mouse hippocampus. Lab Anim Res 2019; 35:20. [PMID: 32257908 PMCID: PMC7081572 DOI: 10.1186/s42826-019-0022-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 10/09/2019] [Indexed: 12/31/2022] Open
Abstract
P53 and its family member p63 play important roles in cellular senescence and organismal aging. In this study, p53 and p63 immunoreactivity were examined in the hippocampus of young, adult and aged mice by using immunohistochemistry. In addition, neuronal distribution and degeneration was examined by NeuN immunohistochemistry and fluoro-Jade B fluorescence staining. Strong p53 immunoreactivity was mainly expressed in pyramidal and granule cells of the hippocampus in young mice. p53 immunoreactivity in the pyramidal and granule cells was significantly reduced in the adult mice. In the aged mice, p53 immunoreactivity in the pyramidal and granule cells was more significantly decreased. p63 immunoreactivity was strong in the pyramidal and granule cells in the young mice. p63 immunoreactivity in these cells was apparently and gradually decreased with age, showing that p63 immunoreactivity in the aged granule cells was hardly shown. However, numbers of pyramidal neurons and granule cells were not significantly decreased in the aged mice with normal aging. Taken together, this study indicates that there are no degenerative neurons in the hippocampus during normal aging, showing that p53 and p63 immunoreactivity in hippocampal neurons was progressively reduced during normal aging, which might be closely related to the normal aging processes.
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Affiliation(s)
- Tae-Kyeong Lee
- 1Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon 24341 Republic of Korea
| | - Young Eun Park
- 1Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon 24341 Republic of Korea
| | - Cheol Woo Park
- 1Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon 24341 Republic of Korea
| | - Bora Kim
- 1Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon 24341 Republic of Korea
| | - Jae-Chul Lee
- 1Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon 24341 Republic of Korea
| | - Joon Ha Park
- 2Department of Anatomy, College of Korean Medicine, Dongguk University, Gyeongju, Gyeongbuk 38066 Republic of Korea
| | - Hyang-Ah Lee
- 3Department of Obstetrics and Gynecology, School of Medicine, Kangwon National University, Chuncheon, Gangwon 24341 Republic of Korea
| | - Moo-Ho Won
- 1Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon 24341 Republic of Korea
| | - Ji Hyeon Ahn
- 4Department of Biomedical Science, Research Institute of Bioscience and Biotechnology, Hallym University, Chuncheon, Gangwon 24252 Republic of Korea
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Down-regulation of cyclin-dependent kinase 5 attenuates p53-dependent apoptosis of hippocampal CA1 pyramidal neurons following transient cerebral ischemia. Sci Rep 2019; 9:13032. [PMID: 31506563 PMCID: PMC6737192 DOI: 10.1038/s41598-019-49623-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 07/10/2019] [Indexed: 01/09/2023] Open
Abstract
Abnormal activation of cyclin-dependent kinase 5 (Cdk5) is associated with pathophysiological conditions. Ischemic preconditioning (IPC) can provide neuroprotective effects against subsequent lethal ischemic insult. The objective of this study was to determine how Cdk5 and related molecules could affect neuroprotection in the hippocampus of gerbils after with IPC [a 2-min transient cerebral ischemia (TCI)] followed by 5-min subsequent TCI. Hippocampal CA1 pyramidal neurons were dead at 5 days post-TCI. However, treatment with roscovitine (a potent inhibitor of Cdk5) and IPC protected CA1 pyramidal neurons from TCI. Expression levels of Cdk5, p25, phospho (p)-Rb and p-p53 were increased in nuclei of CA1 pyramidal neurons at 1 and 2 days after TCI. However, these expressions were attenuated by roscovitine treatment and IPC. In particular, Cdk5, p-Rb and p-p53 immunoreactivities in their nuclei were decreased. Furthermore, TUNEL-positive CA1 pyramidal neurons were found at 5 days after TCI with increased expression levels of Bax, PUMA, and activated caspase-3. These TUNEL-positive cells and increased molecules were decreased by roscovitine treatment and IPC. Thus, roscovitine treatment and IPC could protect CA1 pyramidal neurons from TCI through down-regulating Cdk5, p25, and p-p53 in their nuclei. These findings indicate that down-regulating Cdk5 might be a key strategy to attenuate p53-dependent apoptosis of CA1 pyramidal neurons following TCI.
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Notch signaling and neuronal death in stroke. Prog Neurobiol 2018; 165-167:103-116. [PMID: 29574014 DOI: 10.1016/j.pneurobio.2018.03.002] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 02/08/2018] [Accepted: 03/20/2018] [Indexed: 12/18/2022]
Abstract
Ischemic stroke is a leading cause of morbidity and death, with the outcome largely determined by the amount of hypoxia-related neuronal death in the affected brain regions. Cerebral ischemia and hypoxia activate the Notch1 signaling pathway and four prominent interacting pathways (NF-κB, p53, HIF-1α and Pin1) that converge on a conserved DNA-associated nuclear multi-protein complex, which controls the expression of genes that can determine the fate of neurons. When neurons experience a moderate level of ischemic insult, the nuclear multi-protein complex up-regulates adaptive stress response genes encoding proteins that promote neuronal survival, but when ischemia is more severe the nuclear multi-protein complex induces genes encoding proteins that trigger and execute a neuronal death program. We propose that the nuclear multi-protein transcriptional complex is a molecular mediator of neuronal hormesis and a target for therapeutic intervention in stroke.
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The MDM2-p53 pathway is involved in preconditioning-induced neuronal tolerance to ischemia. Sci Rep 2018; 8:1610. [PMID: 29371613 PMCID: PMC5785500 DOI: 10.1038/s41598-018-19921-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 01/10/2018] [Indexed: 01/01/2023] Open
Abstract
Brain preconditioning (PC) refers to a state of transient tolerance against a lethal insult that can be evoked by a prior mild event. It is thought that PC may induce different pathways responsible for neuroprotection, which may involve the attenuation of cell damage pathways, including the apoptotic cell death. In this context, p53 is a stress sensor that accumulates during brain ischemia leading to neuronal death. The murine double minute 2 gene (MDM2), a p53-specific E3 ubiquitin ligase, is the main cellular antagonist of p53, mediating its degradation by the proteasome. Here, we study the role of MDM2-p53 pathway on PC-induced neuroprotection both in cultured neurons (in vitro) and rat brain (in vivo). Our results show that PC increased neuronal MDM2 protein levels, which prevented ischemia-induced p53 stabilization and neuronal death. Indeed, PC attenuated ischemia-induced activation of the p53/PUMA/caspase-3 signaling pathway. Pharmacological inhibition of MDM2-p53 interaction in neurons abrogated PC-induced neuroprotection against ischemia. Finally, the relevance of the MDM2-p53 pathway was confirmed in rat brain using a PC model in vivo. These findings demonstrate the key role of the MDM2-p53 pathway in PC-induced neuroprotection against a subsequent ischemic insult and poses MDM2 as an essential target in ischemic tolerance.
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Peters M, Wielsch B, Boltze J. The role of SUMOylation in cerebral hypoxia and ischemia. Neurochem Int 2017; 107:66-77. [DOI: 10.1016/j.neuint.2017.03.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 03/09/2017] [Accepted: 03/15/2017] [Indexed: 10/19/2022]
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10
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Li J, Chen G, Gao X, Shen C, Zhou P, Wu X, Che X, Xie R. p53 participates in the protective effects of ischemic post-conditioning against OGD-reperfusion injury in primary cultured spinal cord neurons. Neurosci Lett 2017; 638:129-134. [DOI: 10.1016/j.neulet.2016.12.037] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 12/10/2016] [Accepted: 12/15/2016] [Indexed: 12/25/2022]
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Yang LY, Greig NH, Huang YN, Hsieh TH, Tweedie D, Yu QS, Hoffer BJ, Luo Y, Kao YC, Wang JY. Post-traumatic administration of the p53 inactivator pifithrin-α oxygen analogue reduces hippocampal neuronal loss and improves cognitive deficits after experimental traumatic brain injury. Neurobiol Dis 2016; 96:216-226. [PMID: 27553877 DOI: 10.1016/j.nbd.2016.08.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 08/04/2016] [Accepted: 08/18/2016] [Indexed: 01/08/2023] Open
Abstract
Traumatic brain injury (TBI) is a major cause of death and disability worldwide. Neuronal apoptosis in the hippocampus has been detected after TBI. The hippocampal dysfunction may result in cognitive deficits in learning, memory, and spatial information processing. Our previous studies demonstrated that a p53 inhibitor, pifithrin-α oxygen analogue (PFT-α (O)), significantly reduced cortical cell death, which is substantial following controlled cortical impact (CCI) TBI, and improved neurological functional outcomes via anti-apoptotic mechanisms. In the present study, we examined the effect of PFT-α (O) on CCI TBI-induced hippocampal cellular pathophysiology in light of this brain region's role in memory. To investigate whether p53-dependent apoptosis plays a role in hippocampal neuronal loss and associated cognitive deficits and to define underlying mechanisms, SD rats were subjected to experimental CCI TBI followed by the administration of PFT-α or PFT-α (O) (2mg/kg, i.v.) or vehicle at 5h after TBI. Magnetic resonance imaging (MRI) scans were acquired at 24h and 7days post-injury to assess evolving structural hippocampal damage. Fluoro-Jade C was used to stain hippocampal sub-regions, including CA1 and dentate gyrus (DG), for cellular degeneration. Neurological functions, including motor and recognition memory, were assessed by behavioral tests at 7days post injury. p53, p53 upregulated modulator of apoptosis (PUMA), 4-hydroxynonenal (4-HNE), cyclooxygenase-IV (COX IV), annexin V and NeuN were visualized by double immunofluorescence staining with cell-specific markers. Levels of mRNA encoding for caspase-3, p53, PUMA, Bcl-2, Bcl-2-associated X protein (BAX) and superoxide dismutase (SOD) were measured by RT-qPCR. Our results showed that post-injury administration of PFT-α and, particularly, PFT-α (O) at 5h dramatically reduced injury volumes in the ipsilateral hippocampus, improved motor outcomes, and ameliorated cognitive deficits at 7days after TBI, as evaluated by novel object recognition and open-field test. PFT-α and especially PFT-α (O) significantly reduced the number of FJC-positive cells in hippocampus CA1 and DG subregions, versus vehicle treatment, and significantly decreased caspase-3 and PUMA mRNA expression. PFT-α (O), but not PFT-α, treatment significantly lowered p53 and elevated SOD2 mRNA expression. Double immunofluorescence staining demonstrated that PFT-α (O) treatment decreased p53, annexin V and 4-HNE positive neurons in the hippocampal CA1 region. Furthermore, PUMA co-localization with the mitochondrial maker COX IV, and the upregulation of PUMA were inhibited by PFT-α (O) after TBI. Our data suggest that PFT-α and especially PFT-α (O) significantly reduce hippocampal neuronal degeneration, and ameliorate neurological and cognitive deficits in vivo via antiapoptotic and antioxidative properties.
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Affiliation(s)
- Ling-Yu Yang
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Nigel H Greig
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Ya-Ni Huang
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Nursing, Hsin Sheng Junior College of Medical Care and Management, Taoyuan, Taiwan
| | - Tsung-Hsun Hsieh
- Department of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Graduate Institute of Neural Regenerative Medicine, Taipei Medical University, Taipei, Taiwan
| | - David Tweedie
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Qian-Sheng Yu
- Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Barry J Hoffer
- Department of Neurosurgery, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Yu Luo
- Department of Neurosurgery, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Yu-Chieh Kao
- Translational Imaging Research Center and Department of Radiology, School of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Jia-Yi Wang
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
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Regenerative repair of Pifithrin-α in cerebral ischemia via VEGF dependent manner. Sci Rep 2016; 6:26295. [PMID: 27212231 PMCID: PMC4876321 DOI: 10.1038/srep26295] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 04/29/2016] [Indexed: 01/01/2023] Open
Abstract
Promoting regenerative repair, including neurogenesis and angiogenesis, may provide a new therapeutic strategy for treatment of stroke. P53, a well-documented transcription factor, has been reported to be involved in cerebral ischemia and also serves as an important regulator of vascular endothelial growth factor (VEGF). However, the role of p53 in endogenous regenerative repair after brain ischemia is poorly understood. In this study, we investigated the effects of PFT-α, a specific p53 inhibitor on neurogenesis and angiogenesis improvement and associated signal pathways in rats impaired by cerebral artery occlusion (MCAo). PFT-α induced neuroprotection, reduced infarct volume and neurological functional impairment after ischemic stroke. More importantly, neurogenesis and angiogenesis were greatly enhanced by PFT-α, and accompanied by increased expression of VEGF. Moreover, we got consistent results in neural stem cells (NSCs) isolated from fetal rats. In contrast, application of the anti-VEGF neutralizing antibody (RB-222) partially reversed PFT-α-induced neuroprotection and rescued p53 expression. Noteworthily, inhibition of p53 after ischemic stroke in these rats improved their outcomes via promotion of regenerative repair. In conclusion, PFT-α could serve as a promising therapeutic strategy for ischemic stroke by promoting regenerative repair.
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Miyawaki S, Imai H, Hayasaka T, Masaki N, Ono H, Ochi T, Ito A, Nakatomi H, Setou M, Saito N. Imaging mass spectrometry detects dynamic changes of phosphatidylcholine in rat hippocampal CA1 after transient global ischemia. Neuroscience 2016; 322:66-77. [DOI: 10.1016/j.neuroscience.2016.02.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Revised: 02/02/2016] [Accepted: 02/02/2016] [Indexed: 11/16/2022]
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14
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Schmidt-Kastner R. Genomic approach to selective vulnerability of the hippocampus in brain ischemia–hypoxia. Neuroscience 2015; 309:259-79. [DOI: 10.1016/j.neuroscience.2015.08.034] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Revised: 08/12/2015] [Accepted: 08/17/2015] [Indexed: 01/06/2023]
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Pifithrin-α provides neuroprotective effects at the level of mitochondria independently of p53 inhibition. Apoptosis 2015; 19:1665-77. [PMID: 25343947 DOI: 10.1007/s10495-014-1048-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Impaired mitochondrial integrity and function are key features of intrinsic death pathways in neuronal cells. Therefore, key regulators of intrinsic death pathways acting upstream of mitochondria are potential targets for therapeutic approaches of neuroprotection. The tumor suppressor p53 is a well-established regulator of cellular responses towards different kinds of lethal stress, including oxidative stress. Recent reports suggested that p53 may affect mitochondrial integrity and function through both, transcriptional activation of mitochondria-targeted pro-death proteins and direct effects at the mitochondrial membrane. In the present study, we compared the effects of pharmacological inhibition of p53 by pifithrin-α with those of selective p53 gene silencing by RNA interference. Using MTT assay and real-time cell impedance measurements we confirmed the protective effect of both strategies against glutamate-induced oxidative stress in immortalized mouse hippocampal HT-22 neurons. Further, we observed full restoration of mitochondrial membrane potential and inhibition of glutamate-induced mitochondrial fragmentation by pifithrin-α which was, in contrast, not achieved by p53 gene silencing. Downregulation of p53 by siRNA decreased p53 transcriptional activity and reduced expression levels of p21 mRNA, while pifithrin-α did not affect these endpoints. These results suggest a neuroprotective effect of pifithrin-α which occurred at the level of mitochondria and independently of p53 inhibition.
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Dietary flavonoid fisetin regulates aluminium chloride-induced neuronal apoptosis in cortex and hippocampus of mice brain. J Nutr Biochem 2015; 26:1527-39. [PMID: 26411262 DOI: 10.1016/j.jnutbio.2015.07.017] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 06/24/2015] [Accepted: 07/20/2015] [Indexed: 01/14/2023]
Abstract
Dietary flavonoids have been suggested to promote brain health by protecting brain parenchymal cells. Recently, understanding the possible mechanism underlying neuroprotective efficacy of flavonoids is of great interest. Given that fisetin exerts neuroprotection, we have examined the mechanisms underlying fisetin in regulating Aβ aggregation and neuronal apoptosis induced by aluminium chloride (AlCl3) administration in vivo. Male Swiss albino mice were induced orally with AlCl3 (200 mg/kg. b.wt./day/8 weeks). Fisetin (15 mg/Kg. b.wt. orally) was administered for 4 weeks before AlCl3-induction and administered simultaneously for 8 weeks during AlCl3-induction. We found aggregation of Amyloid beta (Aβ 40-42), elevated expressions of Apoptosis stimulating kinase (ASK-1), p-JNK (c-Jun N-terminal Kinase), p53, cytochrome c, caspases-9 and 3, with altered Bax/Bcl-2 ratio in favour of apoptosis in cortex and hippocampus of AlCl3-administered mice. Furthermore, TUNEL and fluoro-jade C staining demonstrate neurodegeneration in cortex and hippocampus. Notably, treatment with fisetin significantly (P<0.05) reduced Aβ aggregation, ASK-1, p-JNK, p53, cytochrome c, caspase-9 and 3 protein expressions and modulated Bax/Bcl-2 ratio. TUNEL-positive and fluoro-jade C stained cells were also significantly reduced upon fisetin treatment. We have identified the involvement of fisetin in regulating ASK-1 and p-JNK as possible mediator of Aβ aggregation and subsequent neuronal apoptosis during AlCl3-induced neurodegeneration. These findings define the possibility that fisetin may slow or prevent neurodegneration and can be utilised as neuroprotective agent against Alzheimer's and Parkinson's disease.
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Endogenous level of TIGAR in brain is associated with vulnerability of neurons to ischemic injury. Neurosci Bull 2015. [PMID: 26219221 DOI: 10.1007/s12264-015-1538-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In previous studies, we showed that TP53-induced glycolysis and apoptosis regulator (TIGAR) protects neurons against ischemic brain injury. In the present study, we investigated the developmental changes of TIGAR level in mouse brain and the correlation of TIGAR expression with the vulnerability of neurons to ischemic injury. We found that the TIGAR level was high in the embryonic stage, dropped at birth, partially recovered in the early postnatal period, and then continued to decline to a lower level in early adult and aged mice. The TIGAR expression was higher after ischemia/reperfusion in mouse brain 8 and 12 weeks after birth. Four-week-old mice had smaller infarct volumes, lower neurological scores, and lower mortality rates after ischemia than 8- and 12-week-old mice. TIGAR expression also increased in response to oxygen glucose deprivation (OGD)/reoxygenation insult or H2O2 treatment in cultured primary neurons from different embryonic stages (E16 and E20). The neurons cultured from the early embryonic period had a greater resistance to OGD and oxidative insult. Higher TIGAR levels correlated with higher pentose phosphate pathway activity and less oxidative stress. Older mice and more mature neurons had more severe DNA and mitochondrial damage than younger mice and less mature neurons in response to ischemia/reperfusion or OGD/reoxygenation insult. Supplementation of cultured neurons with nicotinamide adenine dinuclectide phosphate (NADPH) significantly reduced ischemic injury. These results suggest that TIGAR expression changes during development and its expression level may be correlated with the vulnerability of neurons to ischemic injury.
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Delayed treatment with NSC23766 in streptozotocin-induced diabetic rats ameliorates post-ischemic neuronal apoptosis through suppression of mitochondrial p53 translocation. Neuropharmacology 2014; 85:508-16. [DOI: 10.1016/j.neuropharm.2014.06.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Revised: 06/03/2014] [Accepted: 06/05/2014] [Indexed: 11/19/2022]
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Abstract
TP53-induced glycolysis and apoptosis regulator (TIGAR) inhibits glycolysis and increases the flow of pentose phosphate pathway (PPP), which generates NADPH and pentose. We hypothesized that TIGAR plays a neuroprotective role in brain ischemia as neurons do not rely on glycolysis but are vulnerable to oxidative stress. We found that TIGAR was highly expressed in brain neurons and was rapidly upregulated in response to ischemia/reperfusion insult in a TP53-independent manner. Overexpression of TIGAR in normal mice with lentivirus reduced ischemic neuronal injury, whereas lentivirus-mediated TIGAR knockdown aggravated it. In cultured primary neurons, increasing TIGAR expression reduced oxygen and glucose deprivation (OGD)/reoxygenation-induced injury, whereas decreasing its expression worsened the injury. The glucose 6-phosphate dehydrogenase was upregulated in mouse and cellular models of stroke, and its upregulation was further enhanced by overexpression of TIGAR. Supplementation of NADPH also reduced ischemia/reperfusion brain injury and alleviated TIGAR knockdown-induced aggravation of ischemic injury. In animal and cellular stroke models, ischemia/reperfusion increased mitochondrial localization of TIGAR. OGD/reoxygenation-induced elevation of ROS, reduction of GSH, dysfunction of mitochondria, and activation of caspase-3 were rescued by overexpression of TIGAR or supplementation of NADPH, while knockdown of TIGAR aggravated these changes. Together, our results show that TIGAR protects ischemic brain injury via enhancing PPP flux and preserving mitochondria function, and thus may be a valuable therapeutic target for ischemic brain injury.
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Zhai D, Chin K, Wang M, Liu F. Disruption of the nuclear p53-GAPDH complex protects against ischemia-induced neuronal damage. Mol Brain 2014; 7:20. [PMID: 24670206 PMCID: PMC3986870 DOI: 10.1186/1756-6606-7-20] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 02/28/2014] [Indexed: 12/24/2022] Open
Abstract
Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) is conventionally considered a critical enzyme that involves in glycolysis for energy production. Recent previous studies have suggested that GAPDH is important in glutamate-induced neuronal excitotoxicity, while accumulated evidence also demonstrated that GAPDH nuclear translocation plays a critical role in cell death. However, the molecular mechanisms underlying this process remain largely unknown. In this study, we showed that GAPDH translocates to the nucleus in a Siah1-dependent manner upon glutamate stimulation. The nuclear GAPDH forms a protein complex with p53 and enhances p53 expression and phosphorylation. Disruption of the GAPDH-p53 interaction with an interfering peptide blocks glutamate-induced cell death and GAPDH-mediated up-regulation of p53 expression and phosphorylation. Furthermore, administration of the interfering peptide in vivo protects against ischemia-induced cell death in rats subjected to tMCAo. Our data suggest that the nuclear p53-GAPDH complex is important in regulating glutamate-mediated neuronal death and could serve as a potential therapeutic target for ischemic stroke treatment.
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Affiliation(s)
| | | | | | - Fang Liu
- Department of Neuroscience, Centre for Addiction and Mental Health, Clarke Division, 250 College Street, Toronto, Ontario M5T 1R8, Canada.
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21
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Silveirinha V, Stephens GJ, Cimarosti H. Molecular targets underlying SUMO-mediated neuroprotection in brain ischemia. J Neurochem 2013; 127:580-91. [PMID: 23786482 DOI: 10.1111/jnc.12347] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 06/14/2013] [Accepted: 06/17/2013] [Indexed: 01/11/2023]
Abstract
SUMOylation (small ubiquitin-like modifier conjugation) is an important post-translational modification which is becoming increasingly implicated in the altered protein dynamics associated with brain ischemia. The function of SUMOylation in cells undergoing ischemic stress and the identity of small ubiquitin-like modifier (SUMO) targets remain in most cases unknown. However, the emerging consensus is that SUMOylation of certain proteins might be part of an endogenous neuroprotective response. This review brings together the current understanding of the underlying mechanisms and downstream effects of SUMOylation in brain ischemia, including processes such as autophagy, mitophagy and oxidative stress. We focus on recent advances and controversies regarding key central nervous system proteins, including those associated with the nucleus, cytoplasm and plasma membrane, such as glucose transporters (GLUT1, GLUT4), excitatory amino acid transporter 2 glutamate transporters, K+ channels (K2P1, Kv1.5, Kv2.1), GluK2 kainate receptors, mGluR8 glutamate receptors and CB1 cannabinoid receptors, which are reported to be SUMO-modified. A discussion of the roles of these molecular targets for SUMOylation could play following an ischemic event, particularly with respect to their potential neuroprotective impact in brain ischemia, is proposed.
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Affiliation(s)
- Vasco Silveirinha
- School of Pharmacy, Hopkins Building, University of Reading, Whiteknights, Reading, UK
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Leak RK, Zhang L, Luo Y, Li P, Zhao H, Liu X, Ling F, Jia J, Chen J, Ji X. Peroxiredoxin 2 battles poly(ADP-ribose) polymerase 1- and p53-dependent prodeath pathways after ischemic injury. Stroke 2013; 44:1124-34. [PMID: 23429506 DOI: 10.1161/strokeaha.111.680157] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Ischemic/reperfusion neuronal injury is characterized by accumulation of reactive oxygen species and oxidative DNA damage, which can trigger cell death by various signaling pathways. Two of these modes of death include poly(ADP-ribose) polymerase 1-mediated death or p53- and Bax-mediated apoptosis. The present study tested the hypothesis that peroxiredoxin 2 (PRX2) attenuates DNA damage-mediated prodeath signaling using in vitro and in vivo models of ischemic injury. The impact of this peroxide scavenger on p53- and poly(ADP-ribose) polymerase 1-mediated ischemic death is unknown. METHODS Neuronal PRX2 overexpression in primary cortical cultures and transgenic mice was combined with the poly(ADP-ribose) polymerase 1 inhibitor AG14361. AG14361 was also applied to p53 and Bax knockout cultures and mice and combined with the JNK inhibitor SP600125. DCF fluorescence, apurinic/apyrimidinic sites, single-strand breaks, Comet tail-length, nicotinamide adenine dinucleotide depletion, and viability were assessed in response to oxygen-glucose deprivation in cultures or transient focal cerebral ischemia in mice. RESULTS PRX2 attenuated reactive oxygen species, DNA damage, nicotinamide adenine dinucleotide depletion, and cell death. PRX2 knockdown exacerbated neuronal death after oxygen and glucose deprivation. PRX2 ameliorated poly(ADP-ribose) polymerase 1, p53, Bax, and caspase activation after ischemia. AG14361 reduced ischemic cell death in wild-type and p53 or Bax knockout cultures and animals but had no additional effect in PRX2-overexpressing mice. AG14361 and p53 knockout elicited additive effects with SP600125 on viability in vitro. Our findings support the existence of multiple parallel prodeath pathways with some crosstalk. CONCLUSIONS The promising therapeutic candidate PRX2 can clamp upstream DNA damage and efficiently inhibit multiple prodeath cascades operating in both parallel and interactive fashions.
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Affiliation(s)
- Rehana K Leak
- Department of Neurosurgery, Cerebrovascular Diseases Research Institute, Xuan Wu Hospital, Capital Medical University, Beijing, China
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Smith JA, Park S, Krause JS, Banik NL. Oxidative stress, DNA damage, and the telomeric complex as therapeutic targets in acute neurodegeneration. Neurochem Int 2013; 62:764-75. [PMID: 23422879 DOI: 10.1016/j.neuint.2013.02.013] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 02/04/2013] [Accepted: 02/08/2013] [Indexed: 01/19/2023]
Abstract
Oxidative stress has been identified as an important contributor to neurodegeneration associated with acute CNS injuries and diseases such as spinal cord injury (SCI), traumatic brain injury (TBI), and ischemic stroke. In this review, we briefly detail the damaging effects of oxidative stress (lipid peroxidation, protein oxidation, etc.) with a particular emphasis on DNA damage. Evidence for DNA damage in acute CNS injuries is presented along with its downstream effects on neuronal viability. In particular, unchecked oxidative DNA damage initiates a series of signaling events (e.g. activation of p53 and PARP-1, cell cycle re-activation) which have been shown to promote neuronal loss following CNS injury. These findings suggest that preventing DNA damage might be an effective way to promote neuronal survival and enhance neurological recovery in these conditions. Finally, we identify the telomere and telomere-associated proteins (e.g. telomerase) as novel therapeutic targets in the treatment of neurodegeneration due to their ability to modulate the neuronal response to both oxidative stress and DNA damage.
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Affiliation(s)
- Joshua A Smith
- Division of Neurology, Department of Neurosciences, Medical University of South Carolina, 96 Jonathan Lucas St., Clinical Sciences Building Room 309, Charleston, SC 29425, USA.
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24
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Almeida A. Genetic determinants of neuronal vulnerability to apoptosis. Cell Mol Life Sci 2013; 70:71-88. [PMID: 22695677 PMCID: PMC11113535 DOI: 10.1007/s00018-012-1029-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 04/22/2012] [Accepted: 05/07/2012] [Indexed: 12/18/2022]
Abstract
Apoptosis is a common mode of cell death that contributes to neuronal loss associated with neurodegeneration. Single-nucleotide polymorphisms (SNPs) in chromosomal DNA are contributing factors dictating natural susceptibility of humans to disease. Here, the most common SNPs affecting neuronal vulnerability to apoptosis are reviewed in the context of neurological disorders. Polymorphic variants in genes encoding apoptotic proteins, either from the extrinsic (FAS, TNF-α, CASP8) or the intrinsic (BAX, BCL2, CASP3, CASP9) pathways could be highly valuable in the diagnosis of neurodegenerative diseases and stroke. Interestingly, the Arg72Pro SNP in TP53, the gene encoding tumor suppressor p53, was recently revealed a biomarker of poor prognosis in stroke due to its ability to modulate neuronal apoptotic death. Search for new SNPs responsible for genetic variability to apoptosis will ensure the implementation of novel diagnostic and prognostic tools, as well as therapeutic strategies against neurological diseases.
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Affiliation(s)
- Angeles Almeida
- Instituto de Investigación Biomédica de Salamanca, Hospital Universitario de Salamanca, 37007, Salamanca, Spain.
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25
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Lei XH, Zhao D, Li YL, Li XF, Sun X, Du WZ, Sun Y, Hao ZF, Xin SY, Liu C, Zhang ZR, Jiang CL. Pifithrin-α enhances the survival of transplanted neural stem cells in stroke rats by inhibiting p53 nuclear translocation. CNS Neurosci Ther 2012; 19:109-16. [PMID: 23253187 DOI: 10.1111/cns.12045] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 11/05/2012] [Accepted: 11/09/2012] [Indexed: 12/16/2022] Open
Abstract
AIMS To examine a novel strategy to enhance the survival of grafted neural stem cells (NSCs) in stroke model. METHODS Using a cell counting kit-8 (CCK-8) and TUNEL assay to test the protective effects of p53 inhibitor, pifithrin-α (PFT-α), on oxygen glucose deprivation (OGD) in NSCs. We compared the effects of vehicle + NSCs and FFT-α + NSCs on the efficacy of transplantation in stroke rat model using behavioral analysis, immunohistochemistry, etc. RESULTS Pifithrin-α increased viability and decreased apoptosis in NSCs after OGD in vitro. By in vivo studies, we showed that the best recovery of neurological function in the stroke rats and the maximum survival of grafted NSCs were found in the PFT-α + NSCs group. Twelve hours after cell transplantation, p53 was localized to the nuclei of grafted NSCs in the vehicle + NSCs group but was primarily localized to the cytoplasm in the PFT-α + NSCs group. The p53-upregulated modulator of apoptosis (PUMA) was highly expressed among the grafted cells in the vehicle + NSCs group compared with that in the PFT-α + NSCs group. CONCLUSION Our results indicate that PFT-α enhances the survival of grafted NSCs through the inhibition of p53 translocation into the nucleus.
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Affiliation(s)
- Xu-Hui Lei
- Department of Neurosurgery, The Second Affiliated Hospital of Harbin Medical University, China
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26
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Raz L, Zhang QG, Han D, Dong Y, De Sevilla L, Brann DW. Acetylation of the pro-apoptotic factor, p53 in the hippocampus following cerebral ischemia and modulation by estrogen. PLoS One 2011; 6:e27039. [PMID: 22046440 PMCID: PMC3202599 DOI: 10.1371/journal.pone.0027039] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Accepted: 10/09/2011] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Recent studies demonstrate that acetylation of the transcription factor, p53 on lysine(373) leads to its enhanced stabilization/activity and increased susceptibility of cells to stress. However, it is not known whether acetylation of p53 is altered in the hippocampus following global cerebral ischemia (GCI) or is regulated by the hormone, 17β-estradiol (17β-E(2)), and thus, this study examined these issues. METHODOLOGY/PRINCIPAL FINDINGS The study revealed that Acetyl p53-Lysine(373) levels were markedly increased in the hippocampal CA1 region after GCI at 3 h, 6 h and 24 h after reperfusion, an effect strongly attenuated by 17β-E(2). 17β-E(2) also enhanced interaction of p53 with the ubiquitin ligase, Mdm2, increased ubiquitination of p53, and induced its down-regulation, as well as attenuated elevation of the p53 transcriptional target, Puma. We also observed enhanced acetylation of p53 at a different lysine (Lys(382)) at 3 h after reperfusion, and 17β-E(2) also markedly attenuated this effect. Furthermore, administration of an inhibitor of CBP/p300 acetyltransferase, which acetylates p53, was strongly neuroprotective of the CA1 region following GCI. In long-term estrogen deprived (LTED) animals, the ability of 17β-E(2) to attenuate p53 acetylation was lost, and intriguingly, Acetyl p53-Lysine(373) levels were markedly elevated in sham (non-ischemic) LTED animals. Finally, intracerebroventricular injections of Gp91ds-Tat, a specific NADPH oxidase (NOX2) inhibitor, but not the scrambled tat peptide control (Sc-Tat), attenuated acetylation of p53 and reduced levels of Puma following GCI. CONCLUSIONS/SIGNIFICANCE The studies demonstrate that p53 undergoes enhanced acetylation in the hippocampal CA1 region following global cerebral ischemia, and that the neuroprotective agent, 17β-E(2), markedly attenuates the ischemia-induced p53 acetylation. Furthermore, following LTED, the suppressive effect of 17β-E(2) on p53 acetylation is lost, and p53 acetylation increases in the hippocampus, which may explain previous reports of increased sensitivity of the hippocampus to ischemic stress following LTED.
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Affiliation(s)
- Limor Raz
- Institute of Molecular Medicine and Genetics, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Quan-guang Zhang
- Institute of Molecular Medicine and Genetics, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Dong Han
- Institute of Molecular Medicine and Genetics, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Yan Dong
- Institute of Molecular Medicine and Genetics, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Liesl De Sevilla
- Institute of Molecular Medicine and Genetics, Georgia Health Sciences University, Augusta, Georgia, United States of America
| | - Darrell W. Brann
- Institute of Molecular Medicine and Genetics, Georgia Health Sciences University, Augusta, Georgia, United States of America
- * E-mail:
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Nijboer CH, Heijnen CJ, van der Kooij MA, Zijlstra J, van Velthoven CTJ, Culmsee C, van Bel F, Hagberg H, Kavelaars A. Targeting the p53 pathway to protect the neonatal ischemic brain. Ann Neurol 2011; 70:255-64. [PMID: 21674585 DOI: 10.1002/ana.22413] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 02/06/2011] [Accepted: 02/25/2011] [Indexed: 11/07/2022]
Abstract
OBJECTIVE To investigate whether inhibition of mitochondrial p53 association using pifithrin-μ (PFT-μ) represents a potential novel neuroprotective strategy to combat perinatal hypoxic-ischemic (HI) brain damage. METHODS Seven-day-old rats were subjected to unilateral carotid artery occlusion and hypoxia followed by intraperitoneal treatment with PFT-μ, an inhibitor of p53 mitochondrial association or PFT-α an inhibitor of p53 transcriptional activity. Cerebral damage, sensorimotor and cognitive function, apoptotic pathways (cytosolic cytochrome c, Smac/DIABLO, active caspase 3), and oxidative stress (lipid peroxidation and PARP-1 cleavage) were investigated. RESULTS PFT-μ treatment completely prevented the HI-induced increase in mitochondrial p53 association at 3 hours and reduced neuronal damage at 48 hours post-HI. PFT-μ had long-term (6-10 weeks post-HI) beneficial effects as sensorimotor and cognitive outcome improved and infarct size was reduced by ~79%. Neuroprotection by PFT-μ treatment was associated with strong inhibition of apoptotic pathways and reduced oxidative stress. Unexpectedly, PFT-μ also inhibited HI-induced upregulation of p53 target genes. However, the neuroprotective effect of inhibiting only p53 transcriptional activity by PFT-α was significantly smaller and did not involve reduced oxidative stress. INTERPRETATION We are the first to show that prevention of mitochondrial p53 association by PFT-μ strongly improves functional outcome and decreases lesion size after neonatal HI. PFT-μ not only inhibits mitochondrial release of cytochrome c, but also inhibits oxidative stress. We propose that as a consequence nuclear accumulation of p53 and transcription of proapoptotic target genes are prevented. In conclusion, targeting p53 mitochondrial association by PFT-μ may develop into a novel and powerful neuroprotective strategy.
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Affiliation(s)
- Cora H Nijboer
- Laboratory of Neuroimmunology and Developmental Origins of Disease, University Medical Center Utrecht, Utrecht, The Netherlands
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Li P, Hu X, Gan Y, Gao Y, Liang W, Chen J. Mechanistic insight into DNA damage and repair in ischemic stroke: exploiting the base excision repair pathway as a model of neuroprotection. Antioxid Redox Signal 2011; 14:1905-18. [PMID: 20677909 PMCID: PMC3078503 DOI: 10.1089/ars.2010.3451] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Stroke is a common cause of death and serious long-term adult disability. Oxidative DNA damage is a severe consequence of oxidative stress associated with ischemic stroke. The accumulation of DNA lesions, including oxidative base modifications and strand breaks, triggers cell death in neurons and other vulnerable cell populations in the ischemic brain. DNA repair systems, particularly base excision repair, are endogenous defense mechanisms that combat oxidative DNA damage. The capacity for DNA repair may affect the susceptibility of neurons to ischemic stress and influence the pathological outcome of stroke. This article reviews the accumulated understanding of molecular pathways by which oxidative DNA damage is triggered and repaired in ischemic cells, and the potential impact of these pathways on ischemic neuronal cell death/survival. Genetic or pharmacological strategies that target the signaling molecules in DNA repair responses are promising for potential clinically effective treatment. Further understanding of mechanisms for oxidative DNA damage and its repair processes may lead to new avenues for stroke management.
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Affiliation(s)
- Peiying Li
- Anesthesiology Department of Huashan Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
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29
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Tomasevic G, Raghupathi R, Scherbel U, Wieloch T, McIntosh TK. Deletion of the p53 tumor suppressor gene improves neuromotor function but does not attenuate regional neuronal cell loss following experimental brain trauma in mice. J Neurosci Res 2011; 88:3414-23. [PMID: 20890990 DOI: 10.1002/jnr.22491] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Deletion of the tumor suppressor gene p53 has been shown to improve the outcome in experimental models of focal cerebral ischemia and kainate-induced seizures. To evaluate the potential role of p53 in traumatic brain injury, genetically modified mice lacking a functional p53 gene (p53(-/-), n = 9) and their wild-type littermates (p53(+/+), n = 9) were anesthetized and subjected to controlled cortical impact (CCI) experimental brain trauma. After brain injury, neuromotor function was assessed by using composite neuroscore and rotarod tests. By 7 days posttrauma, p53(-/-) mice exhibited significantly improved neuromotor function, in the composite neuroscore (P = 0.002) as well as in two of three individual tests, when compared with brain-injured p53(+/+) animals. CCI resulted in the formation of a cortical cavity (mean volume = 6.1 mm(3)) 7 days postinjury in p53(+/+) as well as p53(-/-) mice. No difference in lesion volume was detected between the two genotypes (P = 0.95). Although significant cell loss was detected in the ipsilateral hippocampus and thalamus of brain-injured animals, no differences between p53(+/+) and p53(-/-) mice were detected. Although our results suggest that lack of the p53 gene results in augmented recovery of neuromotor function following experimental brain trauma, they do not support a role for p53 acting as a mediator of neuronal death in this context, underscoring the complexity of its role in the injured brain.
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Affiliation(s)
- Gregor Tomasevic
- Division of Experimental Brain Research, Wallenberg Neuroscience Center, Lund University Hospital, Lund, Sweden.
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30
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Abstract
p53 is a key modulator of cellular stress responses. It is activated in the ischemic areas of brain, and contributes to neuronal apoptosis. In various stroke models, p53 deficiency or applications of p53 inhibitors can significantly attenuate brain damage. p53-mediated neuronal apoptosis occurs through various molecular mechanisms. The transcriptional pathway is an important mechanism through which p53 induces neuronal apoptosis by up-regulating the expression of its target gene p21(WAF), Peg3/Pw1 or p53-up-regulated modulator of apoptosis (PUMA). In addition, p53 disrupts NF-kappaB binding to p300 and blocks NF-kappaB-mediated survival signaling. On the other hand, the transcription-independent pathway mechanism is also of great importance. In this pathway, p53 is translocated to mitochondrial and mediates the release of cytochrome c. In both pathways, p53 seems to play a key role in post-ischemic brain damage and has become a therapeutic target against stroke pathology.
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Soustiel JF, Larisch S. Mitochondrial damage: a target for new therapeutic horizons. Neurotherapeutics 2010; 7:13-21. [PMID: 20129493 PMCID: PMC5084108 DOI: 10.1016/j.nurt.2009.11.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 11/04/2009] [Accepted: 11/04/2009] [Indexed: 12/30/2022] Open
Abstract
Traumatic brain injury (TBI) represents a leading cause of death and morbidity, as well as a considerable social and economical burden in western countries, and has thus emerged as a formidable therapeutic challenge. Yet despite tremendous efforts enlightening the mechanisms of neuronal death, hopes for the "magic bullet" have been repeatedly deceived, and TBI management has remained focused on the control of increased intracranial pressure. Indeed, impairment of cerebral metabolism is traditionally attributed to impaired oxygen delivery mediated by reduced cerebral perfusion in the swollen cerebral parenchyma. Although intuitively appealing, this hypothesis is not entirely supported by physiological facts and does not take into consideration mitochondrial dysfunction that has been repeatedly reported in both human and animal TBI. Although the nature and origin of the events leading to mitochondrial damage may be different, most share a permeabilization of mitochondrial membrane, which therefore may represent a logical target for new therapeutic strategies. Therefore, the proteins mediating these events may represent promising targets for new TBI therapies. Furthermore, mimicking anti-apoptotic proteins, such as Bcl-2 or XIAP, or inhibiting mitochondrial pro-apoptotic proteins, such as Smac/DIABLO, Omi/HTRA2, and ARTS (septin 4 isoform 2) may represent useful novel therapeutic strategies. This review focuses on mechanisms of the mitochondrial membrane permeabilization and its consequences and discusses the current and possible future therapeutic implications of this key event of neuronal death.
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Affiliation(s)
- Jean F Soustiel
- Acute Brain Injury Research Laboratory, Faculty of Medicine, Technion-Israel Institute of Technology, 31096 Haifa, Israel.
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Hong X, Lei L, Künert B, Naredla R, Applequist SE, Grandien A, Glas R. Tripeptidyl-peptidase II Controls DNA Damage Responses and In vivo γ-Irradiation Resistance of Tumors. Cancer Res 2007; 67:7165-74. [PMID: 17671184 DOI: 10.1158/0008-5472.can-06-4094] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cellular responses to gamma-irradiation exposure are controlled by phosphatidylinositol 3-kinase-related kinases (PIKK) in the nucleus, and in addition, cytosolic PIKKs may have a role in such responses. Here, we show that the expression of tripeptidyl-peptidase II (TPPII), a high molecular weight cytosolic peptidase, required PIKK signaling and that TPPII was rapidly translocated into the nucleus of gamma-irradiated cells. These events were dependent on mammalian target of rapamycin, a cytosolic/mitochondrial PIKK that is activated by gamma-irradiation. Lymphoma cells with inhibited expression of TPPII failed to efficiently stabilize p53 and had reduced ability to arrest proliferation in response to gamma-irradiation. We observed that TPPII contains a BRCA COOH-terminal-like motif, contained within sequences of several proteins involved in DNA damage signaling pathways, and this motif was important for nuclear translocation of TPPII and stabilization of p53. Novel tripeptide-based inhibitors of TPPII caused complete in vivo tumor regression in mice in response to relatively low doses of gamma-irradiation (3-4 Gy/wk). This was observed with established mouse and human tumors of diverse tissue backgrounds, with no tumor regrowth after cancellation of treatment. These TPPII inhibitors had minor effects on tumor growth as single agent and had low cellular toxicity. Our data indicated that TPPII connects signaling by cytosolic/mitochondrial and nuclear PIKK-dependent pathways and that TPPII can be targeted for inhibition of tumor therapy resistance.
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Affiliation(s)
- Xu Hong
- Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital-Huddinge
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Racay P, Tatarkova Z, Drgova A, Kaplan P, Dobrota D. Effect of ischemic preconditioning on mitochondrial dysfunction and mitochondrial p53 translocation after transient global cerebral ischemia in rats. Neurochem Res 2007; 32:1823-32. [PMID: 17661174 DOI: 10.1007/s11064-007-9437-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Accepted: 04/02/2007] [Indexed: 11/30/2022]
Abstract
Transient global brain ischemia induces dysfunctions of mitochondria including disturbance in mitochondrial protein synthesis and inhibition of respiratory chain complexes. Due to capacity of mitochondria to release apoptogenic proteins, ischemia-induced mitochondrial dysfunction is considered to be a key event coupling cerebral blood flow arrest to neuronal cell death. Ischemic preconditioning (IPC) represents an important phenomenon of adaptation of central nervous system (CNS) to sub-lethal short-term ischemia, which results in increased tolerance of CNS to the lethal ischemia. In this study we have determined the effect of ischemic preconditioning on ischemia/reperfusion-associated inhibition of mitochondrial protein synthesis and activity of mitochondrial respiratory chain complexes I and IV in the hippocampus of rats. Global brain ischemia was induced by 4-vessel occlusion in duration of 15 min. Rats were preconditioned by 5 min of sub-lethal ischemia and 2 days later, 15 min of lethal ischemia was induced. Our results showed that IPC affects ischemia-induced dysfunction of hippocampal mitochondria in two different ways. Repression of mitochondrial translation induced during reperfusion of the ischemic brain is significantly attenuated by IPC. Slight protective effect of IPC was documented for complex IV, but not for complex I. Despite this, protective effect of IPC on ischemia/reperfusion-associated changes in integrity of mitochondrial membrane and membrane proteins were observed. Since IPC exhibited also inhibitory effect on translocation of p53 to mitochondria, our results indicate that IPC affects downstream processes connecting mitochondrial dysfunction to neuronal cell death.
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Affiliation(s)
- Peter Racay
- Institute of Biochemistry, Jessenius Faculty of Medicine, Comenius University, Mala Hora 4, Martin 03601, Slovak Republic.
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Yamashiro K, Liu R, Maeda M, Hattori N, Urabe T. Induction and selective accumulation of mutant ubiquitin in CA1 pyramidal neurons after transient global ischemia. Neuroscience 2007; 147:71-9. [PMID: 17512670 DOI: 10.1016/j.neuroscience.2007.03.048] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2006] [Revised: 03/12/2007] [Accepted: 03/13/2007] [Indexed: 11/18/2022]
Abstract
Accumulation of mutant ubiquitin-B (UBB(+1)) in neurons is considered the hallmark of proteasomal dysfunction in neurodegenerative disorders, however no such evidence in ischemic brain has been reported. We investigated the contribution of UBB(+1) in delayed neuronal death after transient global ischemia. Transient global ischemia was achieved by occlusion of bilateral common carotid arteries for 5 min and reperfusion in male Mongolian gerbils (n=6 per each time point). In the CA1 region, UBB(+1) immunoreactivity appeared in the cytoplasm of pyramidal cells at 30 min post-ischemia, and the density of these neurons increased at day 2 (P<0.001) and further increased at day 4 post-ischemia. Terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL)-positive (apoptotic) cells appeared selectively in the CA1 region at day 3 and their density increased further at day 4 post-ischemia (P<0.001). In contrast, UBB(+1) immunoreactivity was only transiently detected from 30 min to 1 day post-ischemia in CA3, dentate gyrus, and frontal cortex, but disappeared at day 2 post-ischemia. No TUNEL-positive cells were observed in these three regions. UBB(+1) mRNA was detected by reverse transcription-polymerase chain reaction in every region of the hippocampus and frontal cortex of ischemic gerbils and even in the non-ischemic control animals, and its expression level was independent of brain region and time after ischemia. Our results indicate induction and selective accumulation of UBB(+1) protein in dying neurons of the CA1 region and suggest that UBB(+1) expression may be induced by proteasomal dysfunction after transient global ischemia.
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Affiliation(s)
- K Yamashiro
- Department of Neurology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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Endo H, Kamada H, Nito C, Nishi T, Chan PH. Mitochondrial translocation of p53 mediates release of cytochrome c and hippocampal CA1 neuronal death after transient global cerebral ischemia in rats. J Neurosci 2006; 26:7974-83. [PMID: 16870742 PMCID: PMC6674216 DOI: 10.1523/jneurosci.0897-06.2006] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Although p53 is a key modulator of cellular stress responses, the mechanism of p53-mediated apoptosis is ambiguous. p53 can mediate apoptosis in response to death stimuli by transcriptional activation of proapoptotic genes and transcriptional-independent mechanisms. Recent studies have shown that the p53 protein can directly induce permeabilization of the outer mitochondrial membrane by forming a inhibitory complex with a protective Bcl-2 family protein, resulting in cytochrome c release. However, how the mitochondrial p53 pathway mediates neuronal apoptosis after cerebral ischemia remains unclear. We examined the interaction between the mitochondrial p53 pathway and vulnerable hippocampal CA1 neurons in rats using a transient global cerebral ischemia (tGCI) model. Western blot analysis and immunofluorescent staining revealed mitochondrial p53 translocation after tGCI in the hippocampal CA1 neurons. Coimmunoprecipitation revealed that translocated p53 bound to Bcl-X(L) in the mitochondrial fraction. To examine the effect of a specific p53 inhibitor on the mitochondrial p53 pathway and apoptotic cell death after tGCI, we intravenously administered pifithrin-alpha (PFT). Mitochondrial p53 translocation and interaction between p53 and Bcl-X(L) were prevented by treatment with PFT. Moreover, cytochrome c release from mitochondria and subsequent apoptotic CA1 neuronal death were decreased with PFT treatment. These results suggest that the mitochondrial p53 pathway is one of the novel mechanisms mediating delayed death of vulnerable hippocampal CA1 neurons after tGCI.
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