1
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Yuan J, Mo L, Mo Y, Zhang Y, Zhang Y, Zhang Q. A protective role of autophagy in fine airborne particulate matter-induced apoptosis in LN-229 cells. Toxicology 2022; 477:153271. [PMID: 35872226 PMCID: PMC10825875 DOI: 10.1016/j.tox.2022.153271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/15/2022] [Accepted: 07/20/2022] [Indexed: 01/16/2023]
Abstract
Air pollution is a public health threat and global epidemiological studies have shown that ambient air pollutants are closely related to various poor health conditions, including neurodegenerative diseases. Here, we evaluated the toxic effects and the underlying mechanisms of fine airborne particulate matter (PM2.5) on human glioblastoma LN-229 cells. Our results showed that exposure of LN-229 cells to PM2.5 (≥ 200 μg/mL) significantly reduced cell viability. PM2.5 exposure increased autophagy, apoptosis, and ROS production in the cells. Pre-treatment with a ROS scavenger, catalase, or depletion of mtDNA (ρ0 cells) abolished PM2.5-induced autophagy and apoptosis. PM2.5 exposure also activated MAPK signals in cells, which were blocked by catalase pre-treatment or mtDNA depletion. Furthermore, inhibition of JNK, but not ERK1/2 or p38, attenuated PM2.5-induced autophagy and apoptosis in cells. Finally, suppression of autophagy with Bafilomycin A1 or Beclin 1 siRNA exacerbated PM2.5-induced apoptosis, indicating a protective role of autophagy against PM2.5-induced apoptosis. Our results demonstrated that exposure of LN-229 cells to PM2.5 caused autophagy and apoptosis through PM2.5-induced ROS generation, mainly by mitochondria, and JNK activation. Autophagy may have a transient protective response in PM2.5-induced apoptosis. These findings have important implications for understanding the potential neurotoxicity of PM2.5.
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Affiliation(s)
- Jiali Yuan
- Department of Epidemiology & Population Health, School of Public Health and Information Sciences, University of Louisville, Louisville, KY, USA
| | - Luke Mo
- duPont Manual High School, Louisville, KY, USA
| | - Yiqun Mo
- Department of Epidemiology & Population Health, School of Public Health and Information Sciences, University of Louisville, Louisville, KY, USA
| | - Yuanbao Zhang
- Department of Epidemiology & Population Health, School of Public Health and Information Sciences, University of Louisville, Louisville, KY, USA
| | - Yue Zhang
- Department of Epidemiology & Population Health, School of Public Health and Information Sciences, University of Louisville, Louisville, KY, USA
| | - Qunwei Zhang
- Department of Epidemiology & Population Health, School of Public Health and Information Sciences, University of Louisville, Louisville, KY, USA.
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2
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Correia SC, Moreira PI. Oxygen Sensing and Signaling in Alzheimer's Disease: A Breathtaking Story! Cell Mol Neurobiol 2021; 42:3-21. [PMID: 34510330 DOI: 10.1007/s10571-021-01148-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 09/07/2021] [Indexed: 10/20/2022]
Abstract
Oxygen sensing and homeostasis is indispensable for the maintenance of brain structural and functional integrity. Under low-oxygen tension, the non-diseased brain has the ability to cope with hypoxia by triggering a homeostatic response governed by the highly conserved hypoxia-inducible family (HIF) of transcription factors. With the advent of advanced neuroimaging tools, it is now recognized that cerebral hypoperfusion, and consequently hypoxia, is a consistent feature along the Alzheimer's disease (AD) continuum. Of note, the reduction in cerebral blood flow and tissue oxygenation detected during the prodromal phases of AD, drastically aggravates as disease progresses. Within this scenario a fundamental question arises: How HIF-driven homeostatic brain response to hypoxia "behaves" during the AD continuum? In this sense, the present review is aimed to critically discuss and summarize the current knowledge regarding the involvement of hypoxia and HIF signaling in the onset and progression of AD pathology. Importantly, the promises and challenges of non-pharmacological and pharmacological strategies aimed to target hypoxia will be discussed as a new "hope" to prevent and/or postpone the neurodegenerative events that occur in the AD brain.
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Affiliation(s)
- Sónia C Correia
- CNC - Center for Neuroscience and Cell Biology, Faculty of Medicine, University of Coimbra, Rua Larga, Polo I, 1st Floor, 3004-504, Coimbra, Portugal. .,CIBB - Center for Innovative Biomedicine and Biotechnology, University of Coimbra, Coimbra, Portugal. .,Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal.
| | - Paula I Moreira
- CNC - Center for Neuroscience and Cell Biology, Faculty of Medicine, University of Coimbra, Rua Larga, Polo I, 1st Floor, 3004-504, Coimbra, Portugal.,CIBB - Center for Innovative Biomedicine and Biotechnology, University of Coimbra, Coimbra, Portugal.,Laboratory of Physiology, Faculty of Medicine, University of Coimbra, 3000-548, Coimbra, Portugal
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3
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Prommahom A, Dharmasaroja P. Effects of eEF1A2 knockdown on autophagy in an MPP +-induced cellular model of Parkinson's disease. Neurosci Res 2020; 164:55-69. [PMID: 32275913 DOI: 10.1016/j.neures.2020.03.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 03/16/2020] [Accepted: 03/30/2020] [Indexed: 11/17/2022]
Abstract
1-Methyl-4-phenylpyridinium ion (MPP+) is widely used to induce a cellular model of Parkinson's disease (PD) in dopaminergic cell lines. Downregulation of the protein translation elongation factor 1 alpha (eEF1A) has been reported in the brain tissue of PD patients. eEF1A2, an isoform of eEF1A, is associated with lysosome biogenesis that involves the autophagy process. However, the role of eEF1A2 on autophagic activity in PD has not been elucidated. In this work, we investigated the role of eEF1A2 on autophagy using eEF1A2 siRNA knockdown in differentiated SH-SY5Y neuronal cells treated with MPP+. We found that eEF1A2 was upregulated in differentiated cells, which could be silenced by eEF1A2 siRNA. Significantly, cells treated with MPP+ after eEF1A2 knockdown showed a decreased number of LC3 puncta, decreased LC3-II/LC3-I ratio, and decreased phospho-Beclin-1, compared to the MPP+ alone group. These cells showed extensive areas of mitochondria damage, with a reduction of mitochondrial membrane potential, but reduced mitophagy as indicated by the reduced colocalization of LC3 puncta with damaged mitochondria. Cells with eEF1A2 siRNA plus MPP+ treatment aggravated α-synuclein accumulation but reduced colocalization with LC3. As a result, eEF1A2 knockdown decreased viability, increased apoptotic nuclei, increased caspase-3/7 activation and increased cleaved caspase-3 when cells were treated with MPP+. These results suggest that eEF1A2 is essential for dopaminergic neuron survival against MPP+, in part through autophagy regulation.
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Affiliation(s)
- Athinan Prommahom
- Department of Anatomy, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Permphan Dharmasaroja
- Department of Anatomy, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.
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4
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Autophagy as a Homeostatic Mechanism in Response to Stress Conditions in the Central Nervous System. Mol Neurobiol 2019; 56:6594-6608. [DOI: 10.1007/s12035-019-1546-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 03/12/2019] [Indexed: 12/11/2022]
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5
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Lu N, Li X, Tan R, An J, Cai Z, Hu X, Wang F, Wang H, Lu C, Lu H. HIF-1α/Beclin1-Mediated Autophagy Is Involved in Neuroprotection Induced by Hypoxic Preconditioning. J Mol Neurosci 2018; 66:238-250. [PMID: 30203298 PMCID: PMC6182618 DOI: 10.1007/s12031-018-1162-7] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 08/20/2018] [Indexed: 02/07/2023]
Abstract
Hypoxic preconditioning (HPC) exerts a protective effect against hypoxic/ischemic brain injury, and one mechanism explaining this effect may involve the upregulation of hypoxia-inducible factor-1 (HIF-1). Autophagy, an endogenous protective mechanism against hypoxic/ischemic injury, is correlated with the activation of the HIF-1α/Beclin1 signaling pathway. Based on previous studies, we hypothesize that the protective role of HPC may involve autophagy occurring via activation of the HIF-1α/Beclin1 signaling pathway. To test this hypothesis, we evaluated the effects of HPC on oxygen-glucose deprivation/reperfusion (OGD/R)-induced apoptosis and autophagy in SH-SY5Y cells. HPC significantly attenuated OGD/R-induced apoptosis, and this effect was suppressed by the autophagy inhibitor 3-methyladenine and mimicked by the autophagy agonist rapamycin. In control SH-SY5Y cells, HPC upregulated the expression of HIF-1α and downstream molecules such as BNIP3 and Beclin1. Additionally, HPC increased the LC3-II/LC3-I ratio and decreased p62 levels. The increase in the LC3-II/LC3-I ratio was inhibited by the HIF-1α inhibitor YC-1 or by Beclin1-short hairpin RNA (shRNA). In OGD/R-treated SH-SY5Y cells, HPC also upregulated the expression levels of HIF-1α, BNIP3, and Beclin1, as well as the LC3-II/LC3-I ratio. Furthermore, YC-1 or Beclin1-shRNA attenuated the HPC-mediated cell viability in OGD/R-treated cells. Taken together, our results demonstrate that HPC protects SH-SY5Y cells against OGD/R via HIF-1α/Beclin1-regulated autophagy.
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Affiliation(s)
- Na Lu
- Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China
- Key Laboratory for the Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, 453003, Henan, People's Republic of China
| | - Xingxing Li
- Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Ruolan Tan
- Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Jing An
- Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Zhenlu Cai
- Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Xiaoxuan Hu
- Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Feidi Wang
- Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Haoruo Wang
- Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Chengbiao Lu
- Key Laboratory for the Brain Research of Henan Province, Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, 453003, Henan, People's Republic of China
| | - Haixia Lu
- Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, 710061, Shaanxi, People's Republic of China.
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6
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Tan X, Azad S, Ji X. Hypoxic Preconditioning Protects SH-SY5Y Cell against Oxidative Stress through Activation of Autophagy. Cell Transplant 2018; 27:1753-1762. [PMID: 29871517 PMCID: PMC6300772 DOI: 10.1177/0963689718760486] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Oxidative stress plays a role in many neurological diseases. Hypoxic preconditioning (HPC) has been proposed as an intervention that protects neurons from damage by altering their response to oxidative stress. The aim of this study was to investigate the mechanisms by which HPC results in neuroprotection in cultured SH-SY5Y cells subjected to oxidative stress to provide a guide for future investigation and targeted interventions. SH-SY5Y cells were subjected to HPC protocols or control conditions. Oxidative stress was induced by H2O2. Cell viability was determined via adenosine triphosphate assay. Rapamycin and 3-methyxanthine (3-MA) were used to induce and inhibit autophagy, respectively. Monodansylcadaverine staining was used to observe the formation of autophagosomes. Levels of Microtubule-associated protein light chain 3 B (LC3B), Beclin 1, and p53 were measured by Western blot. Reactive oxygen species (ROS) were also determined. Cell viability in the HPC group following 24-h exposure to 600 μM H2O2 was 65.04 ± 12.91% versus 33.14 ± 5.55% in the control group. LC3B, Beclin 1, and autophagosomes were increased in the HPC group compared with controls. Rapamycin mimicked the protection and 3-MA decreased the protection. There was a moderate increase in ROS after HPC, but rapamycin can abolish the increase and 3-MA can enhance the increase. p53 accumulated in a manner consistent with cell death, and HPC-treated cells showed reduced accumulation of p53 as compared with controls. Treatment with rapamycin decreased p53 accumulation, and 3-MA inhibited the decrease in p53 induced by HPC. HPC protects against oxidative stress in SH-SY5Y cells. Mechanisms of protection may involve the activation of autophagy induced by ROS generated from HPC and the following decline in p53 level caused by activated autophagy in oxidative stress state. This is in line with recent findings in nonneuronal cell populations and may represent an important advance in understanding how HPC protects neurons from oxidative stress.
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Affiliation(s)
- Xiaomu Tan
- 1 Beijing Key Laboratory of Hypoxia Conditioning Translational Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China.,2 Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China.,3 Department of Neurology, Beijing Luhe Hospital, Capital Medical University, Beijing, China
| | - Sherwin Azad
- 4 Department of Neurosurgery, Wayne State University School of Medicine, Detroit, MI, USA
| | - Xunming Ji
- 2 Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
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7
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Codrich M, Bertuzzi M, Russo R, Francescatto M, Espinoza S, Zentilin L, Giacca M, Cesselli D, Beltrami AP, Ascenzi P, Zucchelli S, Persichetti F, Leanza G, Gustincich S. Neuronal hemoglobin affects dopaminergic cells' response to stress. Cell Death Dis 2017; 8:e2538. [PMID: 28055011 PMCID: PMC5386368 DOI: 10.1038/cddis.2016.458] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 11/21/2016] [Accepted: 12/05/2016] [Indexed: 11/14/2022]
Abstract
Hemoglobin (Hb) is the major protein in erythrocytes and carries oxygen (O2) throughout the body. Recently, Hb has been found synthesized in atypical sites, including the brain. Hb is highly expressed in A9 dopaminergic (DA) neurons of the substantia nigra (SN), whose selective degeneration leads to Parkinson's disease (PD). Here we show that Hb confers DA cells' susceptibility to 1-methyl-4-phenylpyridinium (MPP+) and rotenone, neurochemical cellular models of PD. The toxic property of Hb does not depend on O2 binding and is associated with insoluble aggregate formation in the nucleolus. Neurochemical stress induces epigenetic modifications, nucleolar alterations and autophagy inhibition that depend on Hb expression. When adeno-associated viruses carrying α- and β-chains of Hb are stereotaxically injected into mouse SN, Hb forms aggregates and causes motor learning impairment. These results position Hb as a potential player in DA cells' homeostasis and dysfunction in PD.
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Affiliation(s)
- Marta Codrich
- Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), via Bonomea 265, Trieste 34136, Italy
- Department of Health Sciences, University of Eastern Piedmont ‘A. Avogadro', via Solaroli 17, 28100 Novara, Italy
| | - Maria Bertuzzi
- Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), via Bonomea 265, Trieste 34136, Italy
| | - Roberta Russo
- Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), via Bonomea 265, Trieste 34136, Italy
| | - Margherita Francescatto
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia (IIT), via Morego 30, Genova 16163, Italy
| | - Stefano Espinoza
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia (IIT), via Morego 30, Genova 16163, Italy
| | | | | | - Daniela Cesselli
- Department of Medical and Biological Sciences, University of Udine, Piazzale Kolbe 4, Udine, 33100, Italy
| | - Antonio Paolo Beltrami
- Department of Medical and Biological Sciences, University of Udine, Piazzale Kolbe 4, Udine, 33100, Italy
| | - Paolo Ascenzi
- Department of Sciences, University of Roma Tre, viale G. Marconi 446, Roma 00146, Italy
| | - Silvia Zucchelli
- Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), via Bonomea 265, Trieste 34136, Italy
- Department of Health Sciences, University of Eastern Piedmont ‘A. Avogadro', via Solaroli 17, 28100 Novara, Italy
| | - Francesca Persichetti
- Department of Health Sciences, University of Eastern Piedmont ‘A. Avogadro', via Solaroli 17, 28100 Novara, Italy
| | - Giampiero Leanza
- Department of Life Sciences, University of Trieste, via Fleming 22, Trieste 34127, Italy
| | - Stefano Gustincich
- Area of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), via Bonomea 265, Trieste 34136, Italy
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia (IIT), via Morego 30, Genova 16163, Italy
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8
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Shibata S, Ishitobi H, Miyaki S, Kawaoka T, Kayashima T, Matsubara K. Carnosic acid protects starvation-induced SH-SY5Y cell death through Erk1/2 and Akt pathways, autophagy, and FoxO3a. Int J Food Sci Nutr 2016; 67:977-82. [PMID: 27435046 DOI: 10.1080/09637486.2016.1208734] [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] [Indexed: 01/07/2023]
Abstract
Carnosic acid (CA) is recognized as a unique neuroprotective compound in the herb rosemary, since it induces expression of antioxidant enzymes including heme oxygenase-1 (HO-1), γ-glutamylcysteine synthase (γ-GCS), and glutathione S-transferase (GST) via activation of nuclear factor erythroid 2-related factor 2 (Nrf2), which is a nuclear transcription factor. In this study, we examined the cytoprotective effects of CA against starvation. We found that CA protected starvation-induced SH-SY5Y cell death by activating Akt and extracellular signal-regulated kinase 1/2 (Erk1/2). Interestingly, CA induced moderate autophagy and dephosphorylation of a transcriptional factor, the forkhead box protein O3a (FoxO3a). These effects of CA play an important role in cytoprotection.
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Affiliation(s)
- Sachi Shibata
- a Department of Human Life Science Education, Graduate School of Education , Hiroshima University , Hiroshima , Japan
| | - Hiroyuki Ishitobi
- b Department of Regenerative Medicine , Medical Center for Translational and Clinical Research, Hiroshima University Hospital , Hiroshima , Japan
| | - Shigeru Miyaki
- b Department of Regenerative Medicine , Medical Center for Translational and Clinical Research, Hiroshima University Hospital , Hiroshima , Japan
| | | | | | - Kiminori Matsubara
- a Department of Human Life Science Education, Graduate School of Education , Hiroshima University , Hiroshima , Japan
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9
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Enhanced nitric oxide-mediated autophagy contributes to the hepatoprotective effects of ischemic preconditioning during ischemia and reperfusion. Nitric Oxide 2016; 58:10-9. [PMID: 27246638 DOI: 10.1016/j.niox.2016.05.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 05/25/2016] [Accepted: 05/27/2016] [Indexed: 12/19/2022]
Abstract
Ischemic preconditioning (IPC) protects against liver ischemia/reperfusion (I/R) injury. Autophagy is an essential cytoprotective system that is rapidly activated by multiple stressors. Nitric oxide (NO) acts as an inducer of IPC. We examined the impact of autophagy in liver IPC and its regulation by NO. Male C57BL/6 mice were subjected to 60 min of hepatic ischemia followed by 6 h of reperfusion. IPC was achieved for 10 min of ischemia followed by 10 min of reperfusion prior to sustained ischemia. N(ω)-Nitro-l-arginine methyl ester (L-NAME, 15 mg/kg, i.v., all NOS inhibitor) and aminoguanidine (AG, 10 mg/kg, i.v., iNOS inhibitor) were injected 10 min before IPC. SB203580 (10 mg/kg, i.p., p38 inhibitor) was injected 30 min before IPC. I/R increased serum alanine aminotransferase activity. IPC attenuated this increase, which was abolished by L-NAME, but not AG. Microtubule-associated protein-1 light chain 3-II levels increased and p62 protein levels decreased after I/R; these changes were augmented by IPC and abolished by L-NAME. I/R increased liver protein expression of autophagy-related protein (Atg)12-Atg5 complex and lysosome-associated membrane protein-2. IPC augmented the expression of these proteins, which were abolished by L-NAME, but not AG. IPC also augmented the level of phosphorylated p38 MAPK induced by I/R and this phosphorylation was abolished by L-NAME. Our findings suggest that IPC-mediated NO protects against I/R-induced liver injury by enhancing autophagic flux.
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10
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Lamine-Ajili A, Fahmy AM, Létourneau M, Chatenet D, Labonté P, Vaudry D, Fournier A. Effect of the pituitary adenylate cyclase-activating polypeptide on the autophagic activation observed in in vitro and in vivo models of Parkinson's disease. Biochim Biophys Acta Mol Basis Dis 2016; 1862:688-695. [PMID: 26769362 DOI: 10.1016/j.bbadis.2016.01.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 12/10/2015] [Accepted: 01/04/2016] [Indexed: 01/09/2023]
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder that leads to destruction of the midbrain dopaminergic (DA) neurons. This phenomenon is related to apoptosis and its activation can be blocked by the pituitary adenylate cyclase-activating polypeptide (PACAP). Growing evidence indicates that autophagy, a self-degradation activity that cleans up the cell, is induced during the course of neurodegenerative diseases. However, the role of autophagy in the pathogenesis of neuronal disorders is yet poorly understood and the potential ability of PACAP to modulate the related autophagic activation has never been significantly investigated. Hence, we explored the putative autophagy-modulating properties of PACAP in in vitro and in vivo models of PD, using the neurotoxic agents 1-methyl-4-phenylpyridinium (MPP(+)) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), respectively, to trigger alterations of DA neurons. In both models, following the toxin exposure, PACAP reduced the autophagic activity as evaluated by the production of LC3 II, the modulation of the p62 protein levels, and the formation of autophagic vacuoles. The ability of PACAP to inhibit autophagy was also observed in an in vitro cell assay by the blocking of the p62-sequestration activity produced with the autophagy inducer rapamycin. Thus, the results demonstrated that autophagy is induced in PD experimental models and that PACAP exhibits not only anti-apoptotic but also anti-autophagic properties.
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Affiliation(s)
- Asma Lamine-Ajili
- INRS, Institut Armand-Frappier, 531 boul. des Prairies, Laval, QC, Canada H7V 1B7; INSERM-U982, Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, IRIB, Université de Rouen, 76821, Mont-Saint-Aignan, France; Laboratoire Samuel-de-Champlain, Université de Rouen, France/INRS, Canada
| | - Ahmed M Fahmy
- INRS, Institut Armand-Frappier, 531 boul. des Prairies, Laval, QC, Canada H7V 1B7
| | - Myriam Létourneau
- INRS, Institut Armand-Frappier, 531 boul. des Prairies, Laval, QC, Canada H7V 1B7; Laboratoire Samuel-de-Champlain, Université de Rouen, France/INRS, Canada
| | - David Chatenet
- INRS, Institut Armand-Frappier, 531 boul. des Prairies, Laval, QC, Canada H7V 1B7
| | - Patrick Labonté
- INRS, Institut Armand-Frappier, 531 boul. des Prairies, Laval, QC, Canada H7V 1B7
| | - David Vaudry
- INSERM-U982, Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, IRIB, Université de Rouen, 76821, Mont-Saint-Aignan, France; Laboratoire Samuel-de-Champlain, Université de Rouen, France/INRS, Canada
| | - Alain Fournier
- INRS, Institut Armand-Frappier, 531 boul. des Prairies, Laval, QC, Canada H7V 1B7; Laboratoire Samuel-de-Champlain, Université de Rouen, France/INRS, Canada.
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11
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Teng YC, Tai YI, Huang HJ, Lin AMY. Melatonin Ameliorates Arsenite-Induced Neurotoxicity: Involvement of Autophagy and Mitochondria. Mol Neurobiol 2015; 52:1015-22. [DOI: 10.1007/s12035-015-9250-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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12
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Teng YC, Jeng CJ, Huang HJ, Lin AMY. Role of autophagy in arsenite-induced neurotoxicity: The involvement of α-synuclein. Toxicol Lett 2015; 233:239-45. [DOI: 10.1016/j.toxlet.2015.01.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 01/26/2015] [Accepted: 01/28/2015] [Indexed: 11/28/2022]
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13
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Corsetti V, Florenzano F, Atlante A, Bobba A, Ciotti MT, Natale F, Della Valle F, Borreca A, Manca A, Meli G, Ferraina C, Feligioni M, D'Aguanno S, Bussani R, Ammassari-Teule M, Nicolin V, Calissano P, Amadoro G. NH2-truncated human tau induces deregulated mitophagy in neurons by aberrant recruitment of Parkin and UCHL-1: implications in Alzheimer's disease. Hum Mol Genet 2015; 24:3058-81. [PMID: 25687137 DOI: 10.1093/hmg/ddv059] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 02/10/2015] [Indexed: 01/26/2023] Open
Abstract
Disarrangement in functions and quality control of mitochondria at synapses are early events in Alzheimer's disease (AD) pathobiology. We reported that a 20-22 kDa NH2-tau fragment mapping between 26 and 230 amino acids of the longest human tau isoform (aka NH2htau): (i) is detectable in cellular and animal AD models, as well in synaptic mitochondria and cerebrospinal fluids (CSF) from human AD subjects; (ii) is neurotoxic in primary hippocampal neurons; (iii) compromises the mitochondrial biology both directly, by inhibiting the ANT-1-dependent ADP/ATP exchange, and indirectly, by impairing their selective autophagic clearance (mitophagy). Here, we show that the extensive Parkin-dependent turnover of mitochondria occurring in NH2htau-expressing post-mitotic neurons plays a pro-death role and that UCHL-1, the cytosolic Ubiquitin-C-terminal hydrolase L1 which directs the physiological remodeling of synapses by controlling ubiquitin homeostasis, critically contributes to mitochondrial and synaptic failure in this in vitro AD model. Pharmacological or genetic suppression of improper mitophagy, either by inhibition of mitochondrial targeting to autophagosomes or by shRNA-mediated silencing of Parkin or UCHL-1 gene expression, restores synaptic and mitochondrial content providing partial but significant protection against the NH2htau-induced neuronal death. Moreover, in mitochondria from human AD synapses, the endogenous NH2htau is stably associated with Parkin and with UCHL-1. Taken together, our studies show a causative link between the excessive mitochondrial turnover and the NH2htau-induced in vitro neuronal death, suggesting that pathogenetic tau truncation may contribute to synaptic deterioration in AD by aberrant recruitment of Parkin and UCHL-1 to mitochondria making them more prone to detrimental autophagic clearance.
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Affiliation(s)
- V Corsetti
- Institute of Translational Pharmacology (IFT) - National Research Council (CNR), Via Fosso del Cavaliere 100-00133, Rome, Italy
| | - F Florenzano
- European Brain Research Institute (EBRI), Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - A Atlante
- Institute of Biomembranes and Bioenergetics (IBBE)-CNR, Via Amendola 165/A, 70126 Bari, Italy
| | - A Bobba
- Institute of Biomembranes and Bioenergetics (IBBE)-CNR, Via Amendola 165/A, 70126 Bari, Italy
| | - M T Ciotti
- Institute of Cellular Biology and Neuroscience (IBCN)-CNR, IRCSS Santa Lucia Foundation Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - F Natale
- Institute of Cellular Biology and Neuroscience (IBCN)-CNR, IRCSS Santa Lucia Foundation Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - F Della Valle
- Institute of Cellular Biology and Neuroscience (IBCN)-CNR, IRCSS Santa Lucia Foundation Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - A Borreca
- Institute of Cellular Biology and Neuroscience (IBCN)-CNR, IRCSS Santa Lucia Foundation Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - A Manca
- European Brain Research Institute (EBRI), Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - G Meli
- European Brain Research Institute (EBRI), Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - C Ferraina
- European Brain Research Institute (EBRI), Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - M Feligioni
- European Brain Research Institute (EBRI), Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - S D'Aguanno
- Institute of Cellular Biology and Neuroscience (IBCN)-CNR, IRCSS Santa Lucia Foundation Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - R Bussani
- UCO Pathological Anatomy and Histopathology Unit, Cattinara Hospital Strada di Fiume 447, 34149 Trieste, Italy and
| | - M Ammassari-Teule
- Institute of Cellular Biology and Neuroscience (IBCN)-CNR, IRCSS Santa Lucia Foundation Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - V Nicolin
- Department of Medical, Surgical and Health Science, University of Trieste, Strada di Fiume 449, 34149 Trieste, Italy
| | - P Calissano
- European Brain Research Institute (EBRI), Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - G Amadoro
- Institute of Translational Pharmacology (IFT) - National Research Council (CNR), Via Fosso del Cavaliere 100-00133, Rome, Italy European Brain Research Institute (EBRI), Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
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14
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Golpich M, Rahmani B, Mohamed Ibrahim N, Dargahi L, Mohamed Z, Raymond AA, Ahmadiani A. Preconditioning as a potential strategy for the prevention of Parkinson's disease. Mol Neurobiol 2014; 51:313-30. [PMID: 24696268 DOI: 10.1007/s12035-014-8689-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Accepted: 03/23/2014] [Indexed: 12/16/2022]
Abstract
Parkinson's disease (PD) is a chronic neurodegenerative movement disorder characterized by the progressive and massive loss of dopaminergic neurons by neuronal apoptosis in the substantia nigra pars compacta and depletion of dopamine in the striatum, which lead to pathological and clinical abnormalities. A numerous of cellular processes including oxidative stress, mitochondrial dysfunction, and accumulation of α-synuclein aggregates are considered to contribute to the pathogenesis of Parkinson's disease. A further understanding of the cellular and molecular mechanisms involved in the pathophysiology of PD is crucial for developing effective diagnostic, preventative, and therapeutic strategies to cure this devastating disorder. Preconditioning (PC) is assumed as a natural adaptive process whereby a subthreshold stimulus can promote protection against a subsequent lethal stimulus in the brain as well as in other tissues that affords robust brain tolerance facing neurodegenerative insults. Multiple lines of evidence have demonstrated that preconditioning as a possible neuroprotective technique may reduce the neural deficits associated with neurodegenerative diseases such as PD. Throughout the last few decades, a lot of efforts have been made to discover the molecular determinants involved in preconditioning-induced protective responses; although, the accurate mechanisms underlying this "tolerance" phenomenon are not fully understood in PD. In this review, we will summarize pathophysiology and current therapeutic approaches in PD and discuss about preconditioning in PD as a potential neuroprotective strategy. Also the role of gene reprogramming and mitochondrial biogenesis involved in the preconditioning-mediated neuroprotective events will be highlighted. Preconditioning may represent a promising therapeutic weapon to combat neurodegeneration.
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Affiliation(s)
- Mojtaba Golpich
- Department of Medicine, Universiti Kebangsaan Malaysia Medical Centre, Cheras, Kuala Lumpur, Malaysia
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15
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Hung KC, Huang HJ, Lin MW, Lei YP, Lin AMY. Roles of autophagy in MPP+-induced neurotoxicity in vivo: the involvement of mitochondria and α-synuclein aggregation. PLoS One 2014; 9:e91074. [PMID: 24646838 PMCID: PMC3960112 DOI: 10.1371/journal.pone.0091074] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 02/07/2014] [Indexed: 12/18/2022] Open
Abstract
Macroautophagy (also known as autophagy) is an intracellular self-eating mechanism and has been proposed as both neuroprotective and neurodestructive in the central nervous system (CNS) neurodegenerative diseases. In the present study, the role of autophagy involving mitochondria and α-synuclein was investigated in MPP+ (1-methyl-4-phenylpyridinium)-induced oxidative injury in chloral hydrate-anesthetized rats in vivo. The oxidative mechanism underlying MPP+-induced neurotoxicity was identified by elevated lipid peroxidation and heme oxygenase-1 levels, a redox-regulated protein in MPP+-infused substantia nigra (SN). At the same time, MPP+ significantly increased LC3-II levels, a hallmark protein of autophagy. To block MPP+-induced autophagy in rat brain, Atg7siRNA was intranigrally infused 4 d prior to MPP+ infusion. Western blot assay showed that in vivo Atg7siRNA transfection not only reduced Atg7 levels in the MPP+-infused SN but attenuated MPP+-induced elevation in LC3-II levels, activation of caspase 9 and reduction in tyrosine hydroxylase levels, indicating that autophagy is pro-death. The immunostaining study demonstrated co-localization of LC3 and succinate dehydrogenase (a mitochondrial complex II) as well as LC3 and α-synuclein, suggesting that autophagy may engulf mitochondria and α-synuclein. Indeed, in vivo Atg7siRNA transfection mitigated MPP+-induced reduction in cytochrome c oxidase. In addition, MPP+-induced autophagy differentially altered the α-synuclein aggregates in the infused SN. In conclusion, autophagy plays a prodeath role in the MPP+-induced oxidative injury by sequestering mitochondria in the rat brain. Moreover, our data suggest that the benefits of autophagy depend on the levels of α-synuclein aggregates in the nigrostriatal dopaminergic system of the rat brain.
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Affiliation(s)
- Kai-Chih Hung
- Department of Physiology, National Yang-Ming University, Taipei, Taiwan
| | - Hui-Ju Huang
- Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Ming-Wei Lin
- Institute of Public Health, National Yang-Ming University, Taipei, Taiwan
| | - Yen-Ping Lei
- Department of Nursing, National Yang-Ming University, Taipei, Taiwan
| | - Anya Maan-yuh Lin
- Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Pharmacology, National Yang-Ming University, Taipei, Taiwan
- * E-mail:
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16
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Competitive HIF Prolyl Hydroxylase Inhibitors Show Protection against Oxidative Stress by a Mechanism Partially Dependent on Glycolysis. ISRN NEUROSCIENCE 2013; 2013:598587. [PMID: 25006572 PMCID: PMC4061615 DOI: 10.1155/2013/598587] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 09/04/2012] [Indexed: 01/20/2023]
Abstract
The hypoxia inducible factor 1 (HIF-1) is a central transcription factor involved in the cellular and molecular adaptation to hypoxia and low glucose supply. The level of HIF-1 is to a large degree regulated by the HIF prolyl hydroxylase enzymes (HPHs) belonging to the Fe(II) and 2-oxoglutarate-dependent dioxygenase superfamily. In the present study, we compared competitive and noncompetitive HPH-inhibitor compounds in two different cell types (SH-SY5Y and PC12). Although the competitive HPH-inhibitor compounds were found to be pharmacologically more potent than the non-competitive compounds at inhibiting HPH2 and HPH1, this was not translated into the cellular effects of the compounds, where the non-competitive inhibitors were actually more potent than the competitive in stabilizing and translocatingHIF1αto the nucleus (quantified with Cellomics ArrayScan technology). This could be explained by the high cellular concentrations of the cofactor 2-oxoglutarate (2-OG) as the competitive inhibitors act by binding to the 2-OG site of the HPH enzymes. Both competitive and non-competitive HPH inhibitors protected the cells against 6-OHDA induced oxidative stress. In addition, the protective effect of a specific HPH inhibitor was partially preserved when the cells were serum starved and exposed to 2-deoxyglucose, an inhibitor of glycolysis, indicating that other processes than restoring energy supply could be important for the HIF-mediated cytoprotection.
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17
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Dodson M, Darley-Usmar V, Zhang J. Cellular metabolic and autophagic pathways: traffic control by redox signaling. Free Radic Biol Med 2013; 63:207-21. [PMID: 23702245 PMCID: PMC3729625 DOI: 10.1016/j.freeradbiomed.2013.05.014] [Citation(s) in RCA: 427] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 05/08/2013] [Accepted: 05/09/2013] [Indexed: 11/16/2022]
Abstract
It has been established that the key metabolic pathways of glycolysis and oxidative phosphorylation are intimately related to redox biology through control of cell signaling. Under physiological conditions glucose metabolism is linked to control of the NADH/NAD redox couple, as well as providing the major reductant, NADPH, for thiol-dependent antioxidant defenses. Retrograde signaling from the mitochondrion to the nucleus or cytosol controls cell growth and differentiation. Under pathological conditions mitochondria are targets for reactive oxygen and nitrogen species and are critical in controlling apoptotic cell death. At the interface of these metabolic pathways, the autophagy-lysosomal pathway functions to maintain mitochondrial quality and generally serves an important cytoprotective function. In this review we will discuss the autophagic response to reactive oxygen and nitrogen species that are generated from perturbations of cellular glucose metabolism and bioenergetic function.
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Affiliation(s)
- Matthew Dodson
- Center for Free Radical Biology, University of Alabama at Birmingham
- Department of Pathology, University of Alabama at Birmingham
| | - Victor Darley-Usmar
- Center for Free Radical Biology, University of Alabama at Birmingham
- Department of Pathology, University of Alabama at Birmingham
| | - Jianhua Zhang
- Center for Free Radical Biology, University of Alabama at Birmingham
- Department of Pathology, University of Alabama at Birmingham
- Department of Veterans Affairs, Birmingham VA Medical Center
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18
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Wang H, Bower KA, Frank JA, Xu M, Luo J. Hypoxic preconditioning alleviates ethanol neurotoxicity: the involvement of autophagy. Neurotox Res 2013; 24:472-7. [PMID: 23568540 DOI: 10.1007/s12640-013-9390-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 03/27/2013] [Accepted: 04/01/2013] [Indexed: 12/11/2022]
Abstract
Ethanol is a neuroteratogen and neurodegeneration is the most devastating consequence of developmental exposure to ethanol. A sublethal preconditioning has been proposed as a neuroprotective strategy against several central nervous system neurodegenerative diseases. We have recently demonstrated that autophagy is a protective response to alleviate ethanol toxicity. A modest hypoxic preconditioning (1 % oxygen) did not cause neurotoxicity but induced autophagy (Tzeng et al. Free Radic Biol Med 49: 839-846, 2010). We, therefore, hypothesize that the modest hypoxic preconditioning may offer a protection against ethanol-induced neurotoxicity. We showed here that the modest hypoxic preconditioning (1 % oxygen) for 8 h significantly alleviated ethanol-induced death of SH-SY5Y neuroblastoma cells. Under the normoxia condition, cell viability in ethanol-exposed cultures (316 mg/dl for 48 h) was 49 ± 6 % of untreated controls; however, with hypoxic preconditioning, cell viability in the ethanol-exposed group increased to 78 ± 7 % of the controls (p < 0.05; n = 3). Bafilomycin A1, an inhibitor of autophagosome and lysosome fusion, blocked hypoxic preconditioning-mediated protection. Similarly, inhibition of autophagic initiation by wortmannin also eliminated hypoxic preconditioning-mediated protection. In contrast, activation of autophagy by rapamycin further enhanced neuroprotection caused by hypoxic preconditioning. Taken together, the results confirm that autophagy is a protective response against ethanol neurotoxicity and the modest hypoxic preconditioning can offer neuroprotection by activating autophagic pathways.
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Affiliation(s)
- Haiping Wang
- Department of Molecular and Biochemical Pharmacology, University of Kentucky College of Medicine, 132 Health Sciences Research Building, 1095 Veterans Drive, Lexington, KY, 40536, USA
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19
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Naves T, Jawhari S, Jauberteau MO, Ratinaud MH, Verdier M. Autophagy takes place in mutated p53 neuroblastoma cells in response to hypoxia mimetic CoCl(2). Biochem Pharmacol 2013; 85:1153-61. [PMID: 23380477 DOI: 10.1016/j.bcp.2013.01.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 01/25/2013] [Accepted: 01/25/2013] [Indexed: 12/19/2022]
Abstract
Solid tumors like neuroblastoma exhibit hypoxic areas, which can lead both to cell death or aggressiveness increase. Hypoxia is a known stress able to induce stabilization of p53, implicated in cell fate regulation. Recently, p53 appeared to be involved in autophagy in an opposite manner, depending on its location: when nuclear, it enhanced transcription of pro-autophagic genes whereas when cytoplasmic, it inhibited the autophagic process. Today, we used cobalt chloride, a hypoxia mimetic that inhibits proteasomal HIF-1 degradation and generates reactive oxygen species (ROS). We focused on CoCl2-induced cell death in a DNA-binding mutated p53 neuroblastoma cell line (SKNBE(2c)). An autophagic signaling was evidenced by an increase of Beclin-1, ATG 5-12, and LC3-II expression whereas the p53(mut) presence decreased with CoCl2 time exposure. Activation of the pathway seemed to protect cells from ROS production and, at least in part, from death. The autophagic inhibitors activated the apoptotic signaling and the death was enhanced. To delineate the eventual implication of the p53(mut) in the autophagic process in response to hypoxia, we monitored signaling in p53(WT)SHSY5Y cells, after either shRNA-p53 down-regulation or transcriptional activity inhibition by pifithrin alpha. We did not detect autophagy neither with p53(wt) nor when p53 was lacking whereas such a response was effective with a mutated or inactivated p53. To conclude, mutated p53 in neuroblastoma cells could be linked with the switch between apoptotic response and cell death by autophagy in response to hypoxic mimetic stress.
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Affiliation(s)
- Thomas Naves
- EA 3842, Université de Limoges, Faculté de Médecine, 2, rue du Docteur Marcland, 87025 Limoges cedex, France
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20
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Chang CF, Huang HJ, Lee HC, Hung KC, Wu RT, Lin AMY. Melatonin attenuates kainic acid-induced neurotoxicity in mouse hippocampus via inhibition of autophagy and α-synuclein aggregation. J Pineal Res 2012; 52:312-21. [PMID: 22212051 DOI: 10.1111/j.1600-079x.2011.00945.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In this study, the protective effect of melatonin on kainic acid (KA)-induced neurotoxicity involving autophagy and α-synuclein aggregation was investigated in the hippocampus of C57/BL6 mice. Our data showed that intraperitoneal injection of KA (20 mg/kg) increased LC3-II levels (a hallmark protein of autophagy) and reduced mitochondrial DNA content and cytochrome c oxidase levels (a protein marker of mitochondria). Atg7 siRNA transfection prevented KA-induced LC3-II elevations and mitochondria loss. Furthermore, Atg7 siRNA attenuated KA-induced activation of caspases 3/12 (biomarkers of apoptosis) and hippocampal neuronal loss, suggesting a pro-apoptotic role of autophagy in the KA-induced neurotoxicity. Nevertheless, KA-induced α-synuclein aggregation was not affected in the Atg7 siRNA-transfected hippocampus. The neuroprotective effect of melatonin (50 mg/kg) orally administered 1 hr prior to KA injection was studied. Melatonin was found to inhibit KA-induced autophagy-lysosomal activation by reducing KA-induced increases in LC3-II, lysosomal-associated membrane protein 2 (a biomarker of lysosomes) and cathepsin B (a lysosomal cysteine protease). Subsequently, KA-induced mitochondria loss was prevented in the melatonin-treated mice. At the same time, melatonin reduced KA-increased HO-1 levels and α-synuclein aggregation. Our immunoprecipitation study showed that melatonin enhanced ubiquitination of α-synuclein monomers and aggregates. The anti-apoptotic effect of melatonin was demonstrated by attenuating KA-induced DNA fragmentation, activation of caspases 3/12, and neuronal loss. Taken together, our study suggests that KA-induced neurotoxicity may be mediated by autophagy and α-synuclein aggregation. Moreover, melatonin may exert its neuroprotection via inhibiting KA-induced autophagy and a subsequent mitochondrial loss as well as reducing α-synuclein aggregation by enhancing α-synuclein ubiquitination in the CNS.
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Affiliation(s)
- Chia-Fu Chang
- Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan
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21
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Zheng F, Yang WJ, Sun KJ, Wan XM, Man N, Wen LP. Hoechst 33342-induced autophagy protected HeLa cells from caspase-independent cell death with the participation of ROS. Free Radic Res 2012; 46:740-9. [PMID: 22375792 DOI: 10.3109/10715762.2012.670701] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Autophagy, an evolutionarily-conserved intracellular organelle and protein degradation process, may exhibit drastically different effects on cell survival depending on the particular environmental and culturing conditions. Hoechst 33342 (HO), a fluorescent dye widely used for staining DNA, has been reported to induce apoptosis in mammalian cells. Here we showed that, in addition to caspase-independent cell death, HO also induced autophagy in HeLa cells, as evidenced by the accumulation of autophagosomes, LC3 form conversion and LC3 puncta formation in a cell line stably expressing GFP-LC3. HO treatment led to generation of reactive oxygen species (ROS), and inhibition of ROS with N-acetyl-l-cysteine (NAC) abrogated both autophagy and caspase-independent cell death. Finally, autophagy played a protective role against caspase-independent cell death, as cell death induced by HO was enhanced under pharmacological and siRNA-mediated genetic inhibition of autophagy.
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Affiliation(s)
- Fang Zheng
- Hefei National Laboratory for Physical Sciences at Microscale & School of Life Sciences, University of Science and Technology of China, Anhui, China
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22
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Dong XX, Wang YR, Qin S, Liang ZQ, Liu BH, Qin ZH, Wang Y. p53 mediates autophagy activation and mitochondria dysfunction in kainic acid-induced excitotoxicity in primary striatal neurons. Neuroscience 2012; 207:52-64. [PMID: 22330834 DOI: 10.1016/j.neuroscience.2012.01.018] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 01/03/2012] [Accepted: 01/11/2012] [Indexed: 12/24/2022]
Abstract
The present study sought to investigate if p53 mediates autophagy activation and mitochondria dysfunction in primary striatal neurons in kainic acid (KA)-induced excitotoxicity. The excitotoxic model of primary striatal neurons was established with KA. The levels of p53, microtubule-associated protein 1 light chain 3 (LC3), Beclin1, and p62 were examined by Western blot and immunostaining. Autophagy activation was also determined with electron microscope. To evaluate the contribution of p53 to autophagy activation and mitochondria dysfunction in KA-induced excitotoxicity, the protein levels of LC3, Beclin1, and p62, the mitochondrial transmembrane potential and the mitochondrial Reactive oxygen species (ROS) after pretreatment with the p53 inhibitor pifithrin-alpha (PFT-α) and the autophagy inhibitor 3-methyladenine (3-MA) were analyzed. Excitotoxic neuronal injury was induced after KA treatment as demonstrated by increases in lactate dehydrogenase (LDH) leakage and was significantly inhibited by PFT-α. Western blot and immunostaining showed that the induction of p53 protein occurred in the cytosol and the nucleus. Increases in autophagic proteins LC3 and Beclin1 were observed, whereas the protein levels of p62 decreased after KA treatment. Electron microscope analysis showed increased autophagosomes in the cytoplasm. The changes in LC3, Beclin1, and p62 levels were blocked by PFT-α, PFT-μ, 3-MA, and E64d but not Z-DEVD-FMK. JC-1 staining showed the depolarization of mitochondrial membrane potential after excitotoxic insult. Mito-tracker and RedoxSensor Red CC-1 staining showed an increased production of mitochondrial ROS after excitotoxic insult. These effects were significantly suppressed after pretreatment with PFT-α and 3-MA. This study suggests that p53 mediates KA-induced autophagy activation and mitochondrial dysfunction in striatal neurons.
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Affiliation(s)
- X X Dong
- Department of Pharmacology and Laboratory of Aging and Nervous Diseases (SZS0703), Soochow University, School of Pharmaceutical Science, Wen Jing Road, Suzhou 215123, China
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Wang X, Su B, Liu W, He X, Gao Y, Castellani RJ, Perry G, Smith MA, Zhu X. DLP1-dependent mitochondrial fragmentation mediates 1-methyl-4-phenylpyridinium toxicity in neurons: implications for Parkinson's disease. Aging Cell 2011; 10:807-23. [PMID: 21615675 DOI: 10.1111/j.1474-9726.2011.00721.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Selective degeneration of nigrostriatal dopaminergic neurons in Parkinson's disease (PD) can be modeled by the administration of the neurotoxin 1-methyl-4-phenylpyridinium (MPP(+) ). Because abnormal mitochondrial dynamics are increasingly implicated in the pathogenesis of PD, in this study, we investigated the effect of MPP(+) on mitochondrial dynamics and assessed temporal and causal relationship with other toxic effects induced by MPP(+) in neuronal cells. In SH-SY5Y cells, MPP(+) causes a rapid increase in mitochondrial fragmentation followed by a second wave of increase in mitochondrial fragmentation, along with increased DLP1 expression and mitochondrial translocation. Genetic inactivation of DLP1 completely blocks MPP(+) -induced mitochondrial fragmentation. Notably, this approach partially rescues MPP(+) -induced decline in ATP levels and ATP/ADP ratio and increased [Ca(2+) ](i) and almost completely prevents increased reactive oxygen species production, loss of mitochondrial membrane potential, enhanced autophagy and cell death, suggesting that mitochondria fragmentation is an upstream event that mediates MPP(+) -induced toxicity. On the other hand, thiol antioxidant N-acetylcysteine or glutamate receptor antagonist D-AP5 also partially alleviates MPP(+) -induced mitochondrial fragmentation, suggesting a vicious spiral of events contributes to MPP(+) -induced toxicity. We further validated our findings in primary rat midbrain dopaminergic neurons that 0.5 μm MPP(+) induced mitochondrial fragmentation only in tyrosine hydroxylase (TH)-positive dopaminergic neurons in a similar pattern to that in SH-SY5Y cells but had no effects on these mitochondrial parameters in TH-negative neurons. Overall, these findings suggest that DLP1-dependent mitochondrial fragmentation plays a crucial role in mediating MPP(+) -induced mitochondria abnormalities and cellular dysfunction and may represent a novel therapeutic target for PD.
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Affiliation(s)
- Xinglong Wang
- Department of Pathology, Case Western Reserve University, 2103 Connell Road, Cleveland, OH 44106, USA
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