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Zhang Q, Zhang J, Jiang C, Qin J, Ke K, Ding F. Involvement of ERK1/2 pathway in neuroprotective effects of pyrroloquinoline quinine against rotenone-induced SH-SY5Y cell injury. Neuroscience 2014; 270:183-91. [DOI: 10.1016/j.neuroscience.2014.04.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 04/04/2014] [Accepted: 04/08/2014] [Indexed: 11/29/2022]
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102
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Transcriptional and metabolic adaptation of human neurons to the mitochondrial toxicant MPP(+). Cell Death Dis 2014; 5:e1222. [PMID: 24810058 PMCID: PMC4047858 DOI: 10.1038/cddis.2014.166] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 03/13/2014] [Accepted: 03/14/2014] [Indexed: 12/20/2022]
Abstract
Assessment of the network of toxicity pathways by Omics technologies and bioinformatic data processing paves the road toward a new toxicology for the twenty-first century. Especially, the upstream network of responses, taking place in toxicant-treated cells before a point of no return is reached, is still little explored. We studied the effects of the model neurotoxicant 1-methyl-4-phenylpyridinium (MPP+) by a combined metabolomics (mass spectrometry) and transcriptomics (microarrays and deep sequencing) approach to provide unbiased data on earliest cellular adaptations to stress. Neural precursor cells (LUHMES) were differentiated to homogeneous cultures of fully postmitotic human dopaminergic neurons, and then exposed to the mitochondrial respiratory chain inhibitor MPP+ (5 μM). At 18–24 h after treatment, intracellular ATP and mitochondrial integrity were still close to control levels, but pronounced transcriptome and metabolome changes were seen. Data on altered glucose flux, depletion of phosphocreatine and oxidative stress (e.g., methionine sulfoxide formation) confirmed the validity of the approach. New findings were related to nuclear paraspeckle depletion, as well as an early activation of branches of the transsulfuration pathway to increase glutathione. Bioinformatic analysis of our data identified the transcription factor ATF-4 as an upstream regulator of early responses. Findings on this signaling pathway and on adaptive increases of glutathione production were confirmed biochemically. Metabolic and transcriptional profiling contributed complementary information on multiple primary and secondary changes that contribute to the cellular response to MPP+. Thus, combined ‘Omics' analysis is a new unbiased approach to unravel earliest metabolic changes, whose balance decides on the final cell fate.
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103
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Jones BC, Huang X, Mailman RB, Lu L, Williams RW. The perplexing paradox of paraquat: the case for host-based susceptibility and postulated neurodegenerative effects. J Biochem Mol Toxicol 2014; 28:191-7. [PMID: 24599642 PMCID: PMC4677573 DOI: 10.1002/jbt.21552] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 01/20/2014] [Accepted: 02/01/2014] [Indexed: 12/13/2022]
Abstract
Paraquat is an herbicide used extensively in agriculture and has also been proposed to be a risk factor for Parkinson's disease. To date, experimental, clinical, and epidemiological data on paraquat neurotoxicity have been equivocal. In this short review, we discuss some technical and biological mechanisms that contribute to inconsistencies regarding paraquat neurotoxicity. We hypothesize that individual genetic variations in susceptibility generate major differences in neurotoxic risk and functional outcome. Identifying these heritable sources of variation in host susceptibility, and their role in complex gene-environment interactions, is crucial to identify risk biomarkers and to devise better prevention and treatment for those exposed to paraquat and other potential neurotoxicants.
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Affiliation(s)
- Byron C Jones
- Department of Biobehavioral Health, The Pennsylvania State University, University Park, PA, USA; Department of Pharmacology, The Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA, USA.
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104
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Zhou S, Wang Z, Klaunig JE. Caenorhabditis elegans neuron degeneration and mitochondrial suppression caused by selected environmental chemicals. INTERNATIONAL JOURNAL OF BIOCHEMISTRY AND MOLECULAR BIOLOGY 2013; 4:191-200. [PMID: 24380023 PMCID: PMC3867705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 10/26/2013] [Indexed: 06/03/2023]
Abstract
Mitochondrial alterations have been documented for many years in the brains of Parkinson's disease (PD), a disorder that is characterized by the selective loss of dopamine neurons. Recent studies have demonstrated that Parkinson's disease-associated proteins are either present in mitochondria or translocated into mitochondria in response to stress, further reinforcing the importance of the mitochondrial function in the pathogenesis of Parkinson's disease. Exposure to environmental chemicals such as pesticides and heavy metals has been suggested as risk factors in the development of Parkinson's disease. It has been reported that a number of environmental agents including tobacco smoke and perfluorinated compounds, pesticides, as well as metals (Mn(2+) and Pb(2+)) modulate mitochondrial function. However the exact mechanism of mitochondrial alteration has not been defined in the context of the development and progression of Parkinson's disease. The complexity of the mammalian system has made it difficult to dissect the molecular components involved in the pathogenesis of Parkinson's disease. In the present study we used the nematode Caenorhabditis elegans (C. elegans) model of neuron degeneration and investigated the effect of environmental chemicals on mitochondrial biogenesis and mitochondrial gene regulation. Chronic exposure to low concentration (2 or 4 μM) of pesticide rotenone, resulted in significant loss of dopamine neuron in C. elegans, a classic feature of Parkinson's disease. We then determined if the rotenone-induced neuron degeneration is accompanied by a change in mitochondria biogenesis. Analysis of mitochondrial genomic replication by quantitative PCR showed a dramatic decrease in mitochondrial DNA (mtDNA) copies of rotenone-treated C. elegans compared to control. This decreased mitochondrial biogenesis occurred prior to the development of loss of dopamine neurons, and was persistent. The inhibition of mtDNA replication was also found in C. elegans exposed to another neuron toxicant Mn(2+) at the concentration 50 or 100 mM. We further examined the mitochondrial gene expression and found significant lower level of mitochondrial complex IV subunits COI and COII in C. elegans exposed to rotenone. These results demonstrate that environmental chemicals cause persistent suppression of mitochondrial biogenesis and mitochondrial gene expression, and suggest a critical role of modifying mitochondrial biogenesis in toxicants-induced neuron degeneration in C. elegans model.
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Affiliation(s)
- Shaoyu Zhou
- Department of Environmental Health, School of Public Health, Indiana UniversityBloomington, IN, USA
- Primetox TechnologiesWuhan, China
| | - Zemin Wang
- Department of Environmental Health, School of Public Health, Indiana UniversityBloomington, IN, USA
| | - James E Klaunig
- Department of Environmental Health, School of Public Health, Indiana UniversityBloomington, IN, USA
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105
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Choi WS, Kim HW, Xia Z. Preparation of primary cultured dopaminergic neurons from mouse brain. Methods Mol Biol 2013; 1018:61-9. [PMID: 23681617 DOI: 10.1007/978-1-62703-444-9_6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Dopaminergic neurons are involved in a variety of normal brain functions; degenerations of these neurons cause diseases in human. Investigation of how dopaminergic neurons respond to extracellular signals and molecular mechanisms regulating dopaminergic neuron survival and death often requires reliable, reproducible, and high-quality primary cultures of dopaminergic neurons. Here, we described methods to dissect and culture these neurons from embryonic mesencephalon of mouse brain. We utilize coverslips made from Aclar film to maximize the number of surviving dopaminergic neuron in the culture and immunocytochemistry of tyrosine hydroxylase (TH) to identify dopaminergic neuron.
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Affiliation(s)
- Won-Seok Choi
- School of Biological Sciences and Technology, College of Natural Sciences, College of Medicine, Chonnam National University, Gwangju, South Korea
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106
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D’Amico E, Factor-Litvak P, Santella RM, Mitsumoto H. Clinical perspective on oxidative stress in sporadic amyotrophic lateral sclerosis. Free Radic Biol Med 2013; 65:509-527. [PMID: 23797033 PMCID: PMC3859834 DOI: 10.1016/j.freeradbiomed.2013.06.029] [Citation(s) in RCA: 216] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 06/14/2013] [Accepted: 06/14/2013] [Indexed: 12/12/2022]
Abstract
Sporadic amyotrophic lateral sclerosis (ALS) is one of the most devastating neurological diseases; most patients die within 3 to 4 years after symptom onset. Oxidative stress is a disturbance in the pro-oxidative/antioxidative balance favoring the pro-oxidative state. Autopsy and laboratory studies in ALS indicate that oxidative stress plays a major role in motor neuron degeneration and astrocyte dysfunction. Oxidative stress biomarkers in cerebrospinal fluid, plasma, and urine are elevated, suggesting that abnormal oxidative stress is generated outside of the central nervous system. Our review indicates that agricultural chemicals, heavy metals, military service, professional sports, excessive physical exertion, chronic head trauma, and certain foods might be modestly associated with ALS risk, with a stronger association between risk and smoking. At the cellular level, these factors are all involved in generating oxidative stress. Experimental studies indicate that a combination of insults that induce modest oxidative stress can exert additive deleterious effects on motor neurons, suggesting that multiple exposures in real-world environments are important. As the disease progresses, nutritional deficiency, cachexia, psychological stress, and impending respiratory failure may further increase oxidative stress. Moreover, accumulating evidence suggests that ALS is possibly a systemic disease. Laboratory, pathologic, and epidemiologic evidence clearly supports the hypothesis that oxidative stress is central in the pathogenic process, particularly in genetically susceptive individuals. If we are to improve ALS treatment, well-designed biochemical and genetic epidemiological studies, combined with a multidisciplinary research approach, are needed and will provide knowledge crucial to our understanding of ALS etiology, pathophysiology, and prognosis.
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Affiliation(s)
- Emanuele D’Amico
- Eleanor and Lou Gehrig MDA/ALS Research Center, The Neurological Institute of New York, Columbia University Medical Center, 710 West 168th Street (NI-9), New York, NY 10032, ;
| | - Pam Factor-Litvak
- Department of Epidemiology, Mailman School of Public Health, Columbia University Medical Center, 722 West 168th Street, New York, NY 10032,
| | - Regina M. Santella
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University Medical Center, 722 West 168th Street, New York, NY 10032,
| | - Hiroshi Mitsumoto
- Eleanor and Lou Gehrig MDA/ALS Research Center, The Neurological Institute of New York, Columbia University Medical Center, 710 West 168th Street (NI-9), New York, NY 10032
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107
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Dagda RK, Das Banerjee T, Janda E. How Parkinsonian toxins dysregulate the autophagy machinery. Int J Mol Sci 2013; 14:22163-89. [PMID: 24217228 PMCID: PMC3856058 DOI: 10.3390/ijms141122163] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 10/28/2013] [Accepted: 10/28/2013] [Indexed: 12/21/2022] Open
Abstract
Since their discovery, Parkinsonian toxins (6-hydroxydopamine, MPP+, paraquat, and rotenone) have been widely employed as in vivo and in vitro chemical models of Parkinson's disease (PD). Alterations in mitochondrial homeostasis, protein quality control pathways, and more recently, autophagy/mitophagy have been implicated in neurotoxin models of PD. Here, we highlight the molecular mechanisms by which different PD toxins dysregulate autophagy/mitophagy and how alterations of these pathways play beneficial or detrimental roles in dopamine neurons. The convergent and divergent effects of PD toxins on mitochondrial function and autophagy/mitophagy are also discussed in this review. Furthermore, we propose new diagnostic tools and discuss how pharmacological modulators of autophagy/mitophagy can be developed as disease-modifying treatments for PD. Finally, we discuss the critical need to identify endogenous and synthetic forms of PD toxins and develop efficient health preventive programs to mitigate the risk of developing PD.
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Affiliation(s)
- Ruben K. Dagda
- Department of Pharmacology, University of Nevada School of Medicine, Manville Building 18A, Reno, NV 89557, USA; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-775-784-4121; Fax: +1-775-784-1620
| | - Tania Das Banerjee
- Department of Pharmacology, University of Nevada School of Medicine, Manville Building 18A, Reno, NV 89557, USA; E-Mail:
| | - Elzbieta Janda
- Department of Health Sciences, Magna Graecia University, Campus Germaneto, 88100 Cantazaro, Italy; E-Mail:
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108
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Microtubule alterations occur early in experimental parkinsonism and the microtubule stabilizer epothilone D is neuroprotective. Sci Rep 2013; 3:1837. [PMID: 23670541 PMCID: PMC3653217 DOI: 10.1038/srep01837] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 04/16/2013] [Indexed: 12/21/2022] Open
Abstract
The role of microtubule (MT) dysfunction in Parkinson's disease is emerging. It is still unknown whether it is a cause or a consequence of neurodegeneration. Our objective was to assess whether alterations of MT stability precede or follow axonal transport impairment and neurite degeneration in experimental parkinsonism induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in C57Bl mice. MPTP induced a time- and dose-dependent increase in fibres with altered mitochondria distribution, and early changes in cytoskeletal proteins and MT stability. Indeed, we observed significant increases in neuron-specific βIII tubulin and enrichment of deTyr tubulin in dopaminergic neurons. Finally, we showed that repeated daily administrations of the MT stabilizer Epothilone D rescued MT defects and attenuated nigrostriatal degeneration induced by MPTP. These data suggest that alteration of ΜΤs is an early event specifically associated with dopaminergic neuron degeneration. Pharmacological stabilization of MTs may be a viable strategy for the management of parkinsonism.
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109
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Bird MJ, Thorburn DR, Frazier AE. Modelling biochemical features of mitochondrial neuropathology. Biochim Biophys Acta Gen Subj 2013; 1840:1380-92. [PMID: 24161927 DOI: 10.1016/j.bbagen.2013.10.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 08/29/2013] [Accepted: 10/11/2013] [Indexed: 12/20/2022]
Abstract
BACKGROUND The neuropathology of mitochondrial disease is well characterised. However, pathophysiological mechanisms at the level of biochemistry and cell biology are less clear. Progress in this area has been hampered by the limited accessibility of neurologically relevant material for analysis. SCOPE OF REVIEW Here we discuss the recent development of a variety of model systems that have greatly extended our capacity to understand the biochemical features associated with mitochondrial neuropathology. These include animal and cell based models, with mutations in both nuclear and mitochondrial DNA encoded genes, which aim to recapitulate the neuropathology and cellular biochemistry of mitochondrial diseases. MAJOR CONCLUSIONS Analysis of neurological tissue and cells from these models suggests that although there is no unifying mode of pathogenesis, dysfunction of the oxidative phosphorylation (OXPHOS) system is often central. This can be associated with altered reactive oxygen species (ROS) generation, disruption of the mitochondrial membrane potential (ΔΨm) and inadequate ATP synthesis. Thus, other cellular processes such as calcium (Ca(2+)) homeostasis, cellular signaling and mitochondrial morphology could be altered, ultimately compromising viability of neuronal cells. GENERAL SIGNIFICANCE Mechanisms of neuronal dysfunction in mitochondrial disease are only just beginning to be characterised, are system dependent and complex, and not merely driven by energy deficiency. The diversity of pathogenic mechanisms emphasises the need for characterisation in a wide range of models, as different therapeutic strategies are likely to be needed for different diseases. This article is part of a Special Issue entitled Frontiers of Mitochondrial Research.
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Affiliation(s)
- Matthew J Bird
- The Murdoch Childrens Research Institute, The Royal Children's Hospital, Melbourne, Australia; Department of Paediatrics, The University of Melbourne, Melbourne, Australia
| | - David R Thorburn
- The Murdoch Childrens Research Institute, The Royal Children's Hospital, Melbourne, Australia; Department of Paediatrics, The University of Melbourne, Melbourne, Australia; Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, Australia
| | - Ann E Frazier
- The Murdoch Childrens Research Institute, The Royal Children's Hospital, Melbourne, Australia; Department of Paediatrics, The University of Melbourne, Melbourne, Australia.
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110
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Pathak D, Berthet A, Nakamura K. Energy failure: does it contribute to neurodegeneration? Ann Neurol 2013; 74:506-16. [PMID: 24038413 PMCID: PMC4092015 DOI: 10.1002/ana.24014] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 08/09/2013] [Accepted: 08/16/2013] [Indexed: 12/11/2022]
Abstract
Energy failure from mitochondrial dysfunction is proposed to be a central mechanism leading to neuronal death in a range of neurodegenerative diseases. However, energy failure has never been directly demonstrated in affected neurons in these diseases, nor has it been proved to produce degeneration in disease models. Therefore, despite considerable indirect evidence, it is not known whether energy failure truly occurs in susceptible neurons, and whether this failure is responsible for their death. This limited understanding results primarily from a lack of sensitivity and resolution of available tools and assays and the inherent limitations of in vitro model systems. Major advances in these methodologies and approaches should greatly enhance our understanding of the relationship between energy failure, neuronal dysfunction, and death, and help us to determine whether boosting bioenergetic function would be an effective therapeutic approach. Here we review the current evidence that energy failure occurs in and contributes to neurodegenerative disease, and consider new approaches that may allow us to better address this central issue.
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Affiliation(s)
- Divya Pathak
- Gladstone Institute of Neurological Disease, University of California, San Francisco, San Francisco, CA
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111
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Abstract
Parkinson's disease (PD) is a chronic, progressive, disabling neurodegenerative disorder that begins in mid to late life and is characterized by motor impairment, autonomic dysfunction, and, in many, psychological and cognitive changes. Recent advances have helped delineate pathogenetic mechanisms, yet the cause of PD in most individuals is unknown. Although at least 15 genes and genetic loci have been associated with PD, identified genetic causes are responsible for only a few percent of cases. Epidemiologic studies have found increased risk of PD associated with exposure to environmental toxicants such as pesticides, solvents, metals, and other pollutants, and many of these compounds recapitulate PD pathology in animal models. This review summarizes the environmental toxicology of PD, highlighting the consistency of observations across cellular, animal, and human studies of PD pathogenesis.
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112
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Sanders LH, Timothy Greenamyre J. Oxidative damage to macromolecules in human Parkinson disease and the rotenone model. Free Radic Biol Med 2013; 62:111-120. [PMID: 23328732 PMCID: PMC3677955 DOI: 10.1016/j.freeradbiomed.2013.01.003] [Citation(s) in RCA: 416] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Revised: 01/08/2013] [Accepted: 01/08/2013] [Indexed: 11/25/2022]
Abstract
Parkinson disease (PD), the most common neurodegenerative movement disorder, is associated with selective degeneration of nigrostriatal dopamine neurons. Although the underlying mechanisms contributing to neurodegeneration in PD seem to be multifactorial, mitochondrial impairment and oxidative stress are widely considered to be central to many forms of the disease. Whether oxidative stress is a cause or a consequence of dopaminergic death, there is substantial evidence for oxidative stress both in human PD patients and in animal models of PD, especially using rotenone, a complex I inhibitor. There are many indices of oxidative stress, but this review covers the recent evidence for oxidative damage to nucleic acids, lipids, and proteins in both the brain and the peripheral tissues in human PD and in the rotenone model. Limitations of the existing literature and future perspectives are discussed. Understanding how each particular macromolecule is damaged by oxidative stress and the interplay of secondary damage to other biomolecules may help us design better targets for the treatment of PD.
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Affiliation(s)
- Laurie H Sanders
- Pittsburgh Institute for Neurodegenerative Diseases, Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - J Timothy Greenamyre
- Pittsburgh Institute for Neurodegenerative Diseases, Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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113
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Abstract
Alzheimer disease (AD) and Parkinson disease (PD) are the two most common age-related neurodegenerative diseases characterized by prominent neurodegeneration in selective neural systems. Although a small fraction of AD and PD cases exhibit evidence of heritability, among which many genes have been identified, the majority are sporadic without known causes. Molecular mechanisms underlying neurodegeneration and pathogenesis of these diseases remain elusive. Convincing evidence demonstrates oxidative stress as a prominent feature in AD and PD and links oxidative stress to the development of neuronal death and neural dysfunction, which suggests a key pathogenic role for oxidative stress in both AD and PD. Notably, mitochondrial dysfunction is also a prominent feature in these diseases, which is likely to be of critical importance in the genesis and amplification of reactive oxygen species and the pathophysiology of these diseases. In this review, we focus on changes in mitochondrial DNA and mitochondrial dynamics, two aspects critical to the maintenance of mitochondrial homeostasis and function, in relationship with oxidative stress in the pathogenesis of AD and PD.
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Affiliation(s)
| | - Xinglong Wang
- Department of Pathology; Department of Neurology, Case Western Reserve University, Cleveland, OH 44106, USA.
| | - Xiongwei Zhu
- Department of Pathology; Department of Neurology, Case Western Reserve University, Cleveland, OH 44106, USA.
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114
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Rodriguez-Rocha H, Garcia-Garcia A, Pickett C, Li S, Jones J, Chen H, Webb B, Choi J, Zhou Y, Zimmerman MC, Franco R. Compartmentalized oxidative stress in dopaminergic cell death induced by pesticides and complex I inhibitors: distinct roles of superoxide anion and superoxide dismutases. Free Radic Biol Med 2013; 61:370-83. [PMID: 23602909 PMCID: PMC3883883 DOI: 10.1016/j.freeradbiomed.2013.04.021] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 04/11/2013] [Accepted: 04/12/2013] [Indexed: 12/21/2022]
Abstract
The loss of dopaminergic neurons induced by the parkinsonian toxins paraquat, rotenone, and 1-methyl-4-phenylpyridinium (MPP(+)) is associated with oxidative stress. However, controversial reports exist regarding the source/compartmentalization of reactive oxygen species (ROS) generation and its exact role in cell death. We aimed to determine in detail the role of superoxide anion (O2(•-)), oxidative stress, and their subcellular compartmentalization in dopaminergic cell death induced by parkinsonian toxins. Oxidative stress and ROS formation were determined in the cytosol, intermembrane (IMS), and mitochondrial matrix compartments, using dihydroethidine derivatives and the redox sensor roGFP, as well as electron paramagnetic resonance spectroscopy. Paraquat induced an increase in ROS and oxidative stress in both the cytosol and the mitochondrial matrix prior to cell death. MPP(+) and rotenone primarily induced an increase in ROS and oxidative stress in the mitochondrial matrix. No oxidative stress was detected at the level of the IMS. In contrast to previous studies, overexpression of manganese superoxide dismutase (MnSOD) or copper/zinc SOD (CuZnSOD) had no effect on alterations in ROS steady-state levels, lipid peroxidation, loss of mitochondrial membrane potential (ΔΨm), and dopaminergic cell death induced by MPP(+) or rotenone. In contrast, paraquat-induced oxidative stress and cell death were selectively reduced by MnSOD overexpression, but not by CuZnSOD or manganese-porphyrins. However, MnSOD also failed to prevent ΔΨm loss. Finally, paraquat, but not MPP(+) or rotenone, induced the transcriptional activation of the redox-sensitive antioxidant response elements (ARE) and nuclear factor kappa-B (NF-κB). These results demonstrate a selective role of mitochondrial O2(•-) in dopaminergic cell death induced by paraquat, and show that toxicity induced by the complex I inhibitors rotenone and MPP(+) does not depend directly on mitochondrial O2(•-) formation.
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Affiliation(s)
- Humberto Rodriguez-Rocha
- Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA; School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA
| | - Aracely Garcia-Garcia
- Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA; School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA
| | - Chillian Pickett
- Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA; School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA
| | - Sumin Li
- Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA; School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA
| | - Jocelyn Jones
- Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198-5850, USA
| | - Han Chen
- Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA
| | - Brian Webb
- Thermo Scientific, Research and Development, Rockford, IL 61105, USA
| | - Jae Choi
- Thermo Scientific, Research and Development, Rockford, IL 61105, USA
| | - You Zhou
- Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA; School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA; Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA
| | - Matthew C Zimmerman
- Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA; Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198-5850, USA
| | - Rodrigo Franco
- Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA; School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA.
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115
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Emmrich JV, Hornik TC, Neher JJ, Brown GC. Rotenone induces neuronal death by microglial phagocytosis of neurons. FEBS J 2013; 280:5030-8. [PMID: 23789887 DOI: 10.1111/febs.12401] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 06/08/2013] [Accepted: 06/11/2013] [Indexed: 12/21/2022]
Abstract
Rotenone, a common pesticide and inhibitor of mitochondrial complex I, induces microglial activation and loss of dopaminergic neurons in models of Parkinson's disease. However, the mechanisms of rotenone neurotoxicity are still poorly defined. Here, we used primary neuronal/glial cultures prepared from rat cerebella to investigate the contribution of microglia to neuronal cell death induced by low concentrations of rotenone. Rotenone at 2.5 nm induced neuronal loss over several days without increasing the numbers of necrotic or apoptotic neurons, and neuronal loss/death could be prevented by selective removal of microglia. Rotenone increased microglial proliferation and phagocytic activity, without increasing tumour necrosis factor-α release. Rotenone-induced neuronal loss/death could be prevented by inhibition of phagocytic signalling between neurons and microglia with: cyclo(Arg-Gly-Asp-d-Phe-Val) (to block the microglial vitronectin receptor); MRS2578 (to block the microglial P2Y6 receptor); or either annexin V or an antibody against phosphatidylserine (to block exposed phosphatidylserine, a well-characterized neuronal 'eat-me' signal). As inhibition of phagocytosis by five different means prevented neuronal loss without increasing neuronal death, these data indicate that rotenone neurotoxicity is at least partially mediated by microglial phagocytosis of otherwise viable neurons (phagoptosis). Thus, neuronal loss in Parkinson's disease and other neurological diseases might be prevented by blocking phagocytic signalling.
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116
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Subramaniam SR, Chesselet MF. Mitochondrial dysfunction and oxidative stress in Parkinson's disease. Prog Neurobiol 2013; 106-107:17-32. [PMID: 23643800 PMCID: PMC3742021 DOI: 10.1016/j.pneurobio.2013.04.004] [Citation(s) in RCA: 521] [Impact Index Per Article: 47.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 04/13/2013] [Accepted: 04/22/2013] [Indexed: 12/12/2022]
Abstract
Parkinson's disease (PD) is a movement disorder that is characterized by the progressive degeneration of dopaminergic neurons in substantia nigra pars compacta resulting in dopamine deficiency in the striatum. Although majority of the PD cases are sporadic several genetic mutations have also been linked to the disease thus providing new opportunities to study the pathology of the illness. Studies in humans and various animal models of PD reveal that mitochondrial dysfunction might be a defect that occurs early in PD pathogenesis and appears to be a widespread feature in both sporadic and monogenic forms of PD. The general mitochondrial abnormalities linked with the disease include mitochondrial electron transport chain impairment, alterations in mitochondrial morphology and dynamics, mitochondrial DNA mutations and anomaly in calcium homeostasis. Mitochondria are vital organelles with multiple functions and their dysfunction can lead to a decline in energy production, generation of reactive oxygen species and induction of stress-induced apoptosis. In this review, we give an outline of mitochondrial functions that are affected in the pathogenesis of sporadic and familial PD, and hence provide insights that might be valuable for focused future research to exploit possible mitochondrial targets for neuroprotective interventions in PD.
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Affiliation(s)
- Sudhakar Raja Subramaniam
- Department of Neurology, David Geffen School of Medicine, UCLA, 710 Westwood Plaza, Los Angeles, CA 90095-1769, USA
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Essential roles of mitochondrial depolarization in neuron loss through microglial activation and attraction toward neurons. Brain Res 2013; 1505:75-85. [PMID: 23415650 DOI: 10.1016/j.brainres.2013.02.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 02/04/2013] [Accepted: 02/05/2013] [Indexed: 12/17/2022]
Abstract
As life spans increased, neurodegenerative disorders that affect aging populations have also increased. Progressive neuronal loss in specific brain regions is the most common cause of neurodegenerative disease; however, key determinants mediating neuron loss are not fully understood. Using a model of mitochondrial membrane potential (ΔΨm) loss, we found only 25% cell loss in SH-SY5Y (SH) neuronal mono-cultures, but interestingly, 85% neuronal loss occurred when neurons were co-cultured with BV2 microglia. SH neurons overexpressing uncoupling protein 2 exhibited an increase in neuron-microglia interactions, which represent an early step in microglial phagocytosis of neurons. This result indicates that ΔΨm loss in SH neurons is an important contributor to recruitment of BV2 microglia. Notably, we show that ΔΨm loss in BV2 microglia plays a crucial role in microglial activation and phagocytosis of damaged SH neurons. Thus, our study demonstrates that ΔΨm loss in both neurons and microglia is a critical determinant of neuron loss. These findings also offer new insights into neuroimmunological and bioenergetical aspects of neurodegenerative disease.
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118
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Breuer ME, Willems PHGM, Smeitink JAM, Koopman WJH, Nooteboom M. Cellular and animal models for mitochondrial complex I deficiency: a focus on the NDUFS4 subunit. IUBMB Life 2013; 65:202-8. [PMID: 23378164 DOI: 10.1002/iub.1127] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 12/04/2012] [Indexed: 11/07/2022]
Abstract
To allow the rational design of effective treatment strategies for human mitochondrial disorders, a proper understanding of their biochemical and pathophysiological aspects is required. The development and evaluation of these strategies require suitable model systems. In humans, inherited complex I (CI) deficiency is one of the most common deficiencies of the mitochondrial oxidative phosphorylation system. During the last decade, various cellular and animal models of CI deficiency have been presented involving mutations and/or deletion of the Ndufs4 gene, which encodes the NDUFS4 subunit of CI. In this review, we discuss these models and their validity for studying human CI deficiency.
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Affiliation(s)
- Megan E Breuer
- Department of Biochemistry, Nijmegen Centre for Molecular Life Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands
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119
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Jantas D, Roman A, Kuśmierczyk J, Lorenc-Koci E, Konieczny J, Lenda T, Lasoń W. The extent of neurodegeneration and neuroprotection in two chemical in vitro models related to Parkinson's disease is critically dependent on cell culture conditions. Neurotox Res 2013; 24:41-54. [PMID: 23307753 DOI: 10.1007/s12640-012-9374-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 12/27/2012] [Accepted: 12/28/2012] [Indexed: 01/21/2023]
Abstract
The proteasome inhibition and mitochondrial dysfunction are involved in pathomechanism of Parkinson's disease. The main aim of this study was to assess how particular culture conditions of human dopaminergic neuroblastoma SH-SY5Y cells could affect the extent of neurodegeneration induced by proteasome inhibitor-lactacystin (LC) and mitochondrial toxin-rotenone (Rot). This study revealed that induction of neuronal differentiation of SH-SY5Y cells with retinoic acid (RA-SH-SY5Y) caused a higher resistance of these cells to LC-evoked cell death when compared to undifferentiated cells (UN-SH-SY5Y). In contrast, RA-SH-SY5Y cells were more vulnerable than the UN-SH-SY5Y to Rot-induced cell damage. Furthermore, we found that a prolonged incubation of the cells under low serum condition (PLSC) significantly increased the LC toxicity in both differentiated and undifferentiated cells. Next, the effects of combined treatment with LC and Rot on cell viability were studied in RA-SH-SY5Y cells under PLSC and normal low serum condition (NLSC). At a low concentration, Rot (0.001-1 μM) attenuated the LC-evoked cell death in RA-SH-SY5Y cells exposed to NLSC. In contrast, under PLSC low concentrations of Rot lacked neuroprotective action while its higher levels (10 μM) enhanced the LC toxicity. Further, we showed that low concentrations of celastrol (Cel; 0.001 μM), a putative neuroprotective agent with antioxidant and anti-inflammatory properties, were able to partially attenuate the Rot-evoked toxicity under both PLSC and NLSC. On the other hand, Cel (0.001 and 0.01 μM) attenuated the LC-induced cell damage only under PLSC. Interestingly, higher concentrations of Cel (>1 μM) reduced cell viability in both UN- and RA-SH-SY5Y but only in UN-SH-SY5Y cells the effect was enhanced under PLSC. The obtained data indicate that toxicity of LC and Rot in SH-SY5Y cell line depends on the stage of cell differentiation and is enhanced in cells cultured for a longer time in low serum medium. Moreover, the neuroprotective properties of Rot and Cel against the LC-induced cell damage can be observed only under particular low serum conditions.
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Affiliation(s)
- D Jantas
- Department of Experimental Neuroendocrinology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343, Kraków, Poland.
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Abstract
Parkinson's disease (PD) is a neurodegenerative disease, which is characterized by progressive death of dopaminergic neurons in the substantia nigra pars compacta. Although mitochondrial dysfunction and oxidative stress are linked to PD pathogenesis, its etiology and pathology remain to be elucidated. Metabolomics investigates metabolite changes in biofluids, cell lysates, tissues and tumors in order to correlate these metabolomic changes to a disease state. Thus, the application of metabolomics to investigate PD provides a systematic approach to understand the pathology of PD, to identify disease biomarkers, and to complement genomics, transcriptomics and proteomics studies. This review will examine current research into PD mechanisms with a focus on mitochondrial dysfunction and oxidative stress. Neurotoxin-based PD animal models and the rationale for metabolomics studies in PD will also be discussed. The review will also explore the potential of NMR metabolomics to address important issues related to PD treatment and diagnosis.
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Affiliation(s)
- Shulei Lei
- University of Nebraska-Lincoln, Department of Chemistry, 722
Hamilton Hall, Lincoln, NE 68588-0304
| | - Robert Powers
- University of Nebraska-Lincoln, Department of Chemistry, 722
Hamilton Hall, Lincoln, NE 68588-0304
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121
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Papa S, De Rasmo D. Complex I deficiencies in neurological disorders. Trends Mol Med 2012; 19:61-9. [PMID: 23265841 DOI: 10.1016/j.molmed.2012.11.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 10/18/2012] [Accepted: 11/15/2012] [Indexed: 12/14/2022]
Abstract
Complex I is the point of entry in the mitochondrial electron transport chain for NADH reducing equivalents, and it behaves as a regulatable pacemaker of respiratory ATP production in human cells. Defects in complex I are associated with several human neurological disorders, including primary mitochondrial diseases, Parkinson disease (PD), and Down syndrome, and understanding the activity and regulation of complex I may reveal aspects of the underlying pathogenic mechanisms. Complex I is regulated by cyclic AMP (cAMP) and the protein kinase A (PKA) signal transduction pathway, and elucidating the role of the cAMP/PKA system in regulating complex I and oxygen free radical production provides new perspectives for devising therapeutic strategies for neurological diseases.
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Affiliation(s)
- Sergio Papa
- Institute of Biomembranes and Bioenergetics (IBBE), Consiglio Nazionale delle Ricerche, Bari, Italy.
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122
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Garcia-Garcia A, Zavala-Flores L, Rodriguez-Rocha H, Franco R. Thiol-redox signaling, dopaminergic cell death, and Parkinson's disease. Antioxid Redox Signal 2012; 17:1764-84. [PMID: 22369136 PMCID: PMC3474187 DOI: 10.1089/ars.2011.4501] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
SIGNIFICANCE Parkinson's disease (PD) is characterized by the selective loss of dopaminergic neurons of the substantia nigra pars compacta, which has been widely associated with oxidative stress. However, the mechanisms by which redox signaling regulates cell death progression remain elusive. RECENT ADVANCES Early studies demonstrated that depletion of glutathione (GSH), the most abundant low-molecular-weight thiol and major antioxidant defense in cells, is one of the earliest biochemical events associated with PD, prompting researchers to determine the role of oxidative stress in dopaminergic cell death. Since then, the concept of oxidative stress has evolved into redox signaling, and its complexity is highlighted by the discovery of a variety of thiol-based redox-dependent processes regulating not only oxidative damage, but also the activation of a myriad of signaling/enzymatic mechanisms. CRITICAL ISSUES GSH and GSH-based antioxidant systems are important regulators of neurodegeneration associated with PD. In addition, thiol-based redox systems, such as peroxiredoxins, thioredoxins, metallothioneins, methionine sulfoxide reductases, transcription factors, as well as oxidative modifications in protein thiols (cysteines), including cysteine hydroxylation, glutathionylation, and nitrosylation, have been demonstrated to regulate dopaminergic cell loss. FUTURE DIRECTIONS In this review, we summarize major advances in the understanding of the role of thiol-redox signaling in dopaminergic cell death in experimental PD. Future research is still required to clearly understand how integrated thiol-redox signaling regulates the activation of the cell death machinery, and the knowledge generated should open new avenues for the design of novel therapeutic approaches against PD.
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Affiliation(s)
- Aracely Garcia-Garcia
- Redox Biology Center and School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, USA
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123
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Panelli D, Lorusso FP, Papa F, Panelli P, Stella A, Caputi M, Sardanelli AM, Papa S. The mechanism of alternative splicing of the X-linked NDUFB11 gene of the respiratory chain complex I, impact of rotenone treatment in neuroblastoma cells. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:211-8. [PMID: 23246602 DOI: 10.1016/j.bbagrm.2012.12.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 11/12/2012] [Accepted: 12/05/2012] [Indexed: 12/25/2022]
Abstract
A study is presented on the regulation of alternative splicing (AS) of the Ndufb11 gene of complex I of the mitochondrial respiratory chain and the impact on this process of rotenone treatment in neuroblastoma cells. In physiological conditions the Ndufb11 gene produces at high level a short transcript isoform encoding for a 153 aa protein. This subunit is essential for the assembly of a functional and stable mammalian complex I. The gene produces also, at low level, a longer transcript isoform encoding for a 163 aa protein whose role is unknown. Evidence is presented here showing that the level of the two isoforms is regulated by three DGGGD ESS elements located in exon 2 which can bind the hnRNPH1 protein. In neuronal cells rotenone treatment affects the Ndufb11 alternative splicing pathway, with the increase of the 163/153 mRNAs ratio. This effect appears to be due to the down-regulation of the hnRNPH1 protein. Since rotenone induces apoptosis in neuronal cells, the post-transcriptional regulation of the Ndufb11 gene can be involved in the programmed cell death process.
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Affiliation(s)
- Damiano Panelli
- Department of Basic Medical Sciences, University of Bari Aldo Moro, Bari, Italy.
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124
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Polster BM. AIF, reactive oxygen species, and neurodegeneration: a "complex" problem. Neurochem Int 2012; 62:695-702. [PMID: 23246553 DOI: 10.1016/j.neuint.2012.12.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 11/26/2012] [Accepted: 12/05/2012] [Indexed: 12/21/2022]
Abstract
Apoptosis-inducing factor (AIF) is a flavin-binding mitochondrial intermembrane space protein that is implicated in diverse but intertwined processes that include maintenance of electron transport chain function, reactive oxygen species regulation, cell death, and neurodegeneration. In acute brain injury, AIF acquires a pro-death role upon translocation from the mitochondria to the nucleus, where it initiates chromatin condensation and large-scale DNA fragmentation. Although harlequin mice exhibiting an 80-90% global reduction in AIF protein are resistant to numerous forms of acute brain injury, they paradoxically undergo slow, progressive neurodegeneration beginning at three months of age. Brain deterioration, accompanied by markers of oxidative stress, is most pronounced in the cerebellum and retina, although it also occurs in the cortex, striatum, and thalamus. Loss of an AIF pro-survival function linked to assembly or stabilization of electron transport chain complex I underlies chronic neurodegeneration. To date, most studies of neurodegeneration have failed to adequately separate the relative importance of the mitochondrial and nuclear functions of AIF in determining the extent of injury, or whether oxidative stress plays a causative role. This review explores the complicated relationship among AIF, complex I, and the regulation of mitochondrial reactive oxygen species levels. It also discusses the controversial role of complex I deficiency in Parkinson's disease, and what can be learned from the AIF- and complex I-depleted harlequin mouse.
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Affiliation(s)
- Brian M Polster
- Department of Anesthesiology and Center for Shock, Trauma and Anesthesiology Research (STAR), University of Maryland School of Medicine, 685 W. Baltimore St., MSTF 5-34, Baltimore, MD 21201, USA.
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125
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Primary fibroblasts of NDUFS4(-/-) mice display increased ROS levels and aberrant mitochondrial morphology. Mitochondrion 2012; 13:436-43. [PMID: 23234723 DOI: 10.1016/j.mito.2012.12.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 11/28/2012] [Accepted: 12/03/2012] [Indexed: 11/22/2022]
Abstract
The human NDUFS4 gene encodes an accessory subunit of the first mitochondrial oxidative phosphorylation complex (CI) and, when mutated, is associated with progressive neurological disorders. Here we analyzed primary muscle and skin fibroblasts from NDUFS4(-/-) mice with respect to reactive oxygen species (ROS) levels and mitochondrial morphology. NDUFS4(-/-) fibroblasts displayed an inactive CI subcomplex on native gels but proliferated normally and showed no obvious signs of apoptosis. Oxidation of the ROS sensor hydroethidium was increased and mitochondria were less branched and/or shorter in NDUFS4(-/-) fibroblasts. We discuss the relevance of these findings with respect to previous results and therapy development.
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126
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Cabeza-Arvelaiz Y, Schiestl RH. Transcriptome analysis of a rotenone model of parkinsonism reveals complex I-tied and -untied toxicity mechanisms common to neurodegenerative diseases. PLoS One 2012; 7:e44700. [PMID: 22970289 PMCID: PMC3436760 DOI: 10.1371/journal.pone.0044700] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 08/09/2012] [Indexed: 12/21/2022] Open
Abstract
The pesticide rotenone, a neurotoxin that inhibits the mitochondrial complex I, and destabilizes microtubules (MT) has been linked to Parkinson disease (PD) etiology and is often used to model this neurodegenerative disease (ND). Many of the mechanisms of action of rotenone are posited mechanisms of neurodegeneration; however, they are not fully understood. Therefore, the study of rotenone-affected functional pathways is pertinent to the understanding of NDs pathogenesis. This report describes the transcriptome analysis of a neuroblastoma (NB) cell line chronically exposed to marginally toxic and moderately toxic doses of rotenone. The results revealed a complex pleiotropic response to rotenone that impacts a variety of cellular events, including cell cycle, DNA damage response, proliferation, differentiation, senescence and cell death, which could lead to survival or neurodegeneration depending on the dose and time of exposure and cell phenotype. The response encompasses an array of physiological pathways, modulated by transcriptional and epigenetic regulatory networks, likely activated by homeostatic alterations. Pathways that incorporate the contribution of MT destabilization to rotenone toxicity are suggested to explain complex I-independent rotenone-induced alterations of metabolism and redox homeostasis. The postulated mechanisms involve the blockage of mitochondrial voltage-dependent anions channels (VDACs) by tubulin, which coupled with other rotenone-induced organelle dysfunctions may underlie many presumed neurodegeneration mechanisms associated with pathophysiological aspects of various NDs including PD, AD and their variant forms. Thus, further investigation of such pathways may help identify novel therapeutic paths for these NDs.
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Affiliation(s)
- Yofre Cabeza-Arvelaiz
- Department of Pathology and Environmental Health Sciences, David Geffen School of Medicine and School of Public Health, University of California Los Angeles, Los Angeles, California, United States of America.
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127
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Giordano S, Lee J, Darley-Usmar VM, Zhang J. Distinct effects of rotenone, 1-methyl-4-phenylpyridinium and 6-hydroxydopamine on cellular bioenergetics and cell death. PLoS One 2012; 7:e44610. [PMID: 22970265 PMCID: PMC3435291 DOI: 10.1371/journal.pone.0044610] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 08/03/2012] [Indexed: 12/21/2022] Open
Abstract
Parkinson's disease is characterized by dopaminergic neurodegeneration and is associated with mitochondrial dysfunction. The bioenergetic susceptibility of dopaminergic neurons to toxins which induce Parkinson's like syndromes in animal models is then of particular interest. For example, rotenone, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its active metabolite 1-methyl-4-phenylpyridinium (MPP(+)), and 6-hydroxydopamine (6-OHDA), have been shown to induce dopaminergic cell death in vivo and in vitro. Exposure of animals to these compounds induce a range of responses characteristics of Parkinson's disease, including dopaminergic cell death, and Reactive Oxygen Species (ROS) production. Here we test the hypothesis that cellular bioenergetic dysfunction caused by these compounds correlates with induction of cell death in differentiated dopaminergic neuroblastoma SH-SY5Y cells. At increasing doses, rotenone induced significant cell death accompanied with caspase 3 activation. At these concentrations, rotenone had an immediate inhibition of mitochondrial basal oxygen consumption rate (OCR) concomitant with a decrease of ATP-linked OCR and reserve capacity, as well as a stimulation of glycolysis. MPP(+) exhibited a different behavior with less pronounced cell death at doses that nearly eliminated basal and ATP-linked OCR. Interestingly, MPP(+), unlike rotenone, stimulated bioenergetic reserve capacity. The effects of 6-OHDA on bioenergetic function was markedly less than the effects of rotenone or MPP(+) at cytotoxic doses, suggesting a mechanism largely independent of bioenergetic dysfunction. These studies suggest that these dopaminergic neurotoxins induce cell death through distinct mechanisms and differential effects on cellular bioenergetics.
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Affiliation(s)
- Samantha Giordano
- Department of Pathology, Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Jisun Lee
- Department of Pathology, Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Victor M. Darley-Usmar
- Department of Pathology, Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Jianhua Zhang
- Department of Pathology, Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- Department of Veterans Affairs, Birmingham VA Medical Center, Birmingham, Alabama, United States of America
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Joselin AP, Hewitt SJ, Callaghan SM, Kim RH, Chung YH, Mak TW, Shen J, Slack RS, Park DS. ROS-dependent regulation of Parkin and DJ-1 localization during oxidative stress in neurons. Hum Mol Genet 2012; 21:4888-903. [PMID: 22872702 DOI: 10.1093/hmg/dds325] [Citation(s) in RCA: 164] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mutations in several genes, including Parkin, PTEN-induced kinase 1 (Pink1) and DJ-1, are associated with rare inherited forms of Parkinson's disease (PD). Despite recent attention on the function of these genes, the interplay between DJ-1, Pink1 and Parkin in PD pathogenesis remains unclear. In particular, whether these genes regulate mitochondrial control pathways in neurons is highly controversial. Here we report that Pink1-dependent Parkin translocation does occur in mouse cortical neurons in response to a variety of mitochondrial damaging agents. This translocation only occurs in the absence of antioxidants in the neuronal culturing medium, implicating a key role of reactive oxygen species (ROS) in this response. Consistent with these observations, ROS blockers also prevent Parkin recruitment in mouse embryonic fibroblasts. Loss of DJ-1, a gene linked to ROS management, results in increased stress-induced Parkin recruitment and increased mitophagy. Expression of wild-type DJ-1, but not a cysteine-106 mutant associated with defective ROS response, rescues this accelerated Parkin recruitment. Interestingly, DJ-1 levels increase at mitochondria following oxidative damage in both fibroblasts and neurons, and this process also depends on Parkin and possibly Pink1. These results not only highlight the presence of a Parkin/Pink1-mediated pathway of mitochondrial quality control (MQC) in neurons, they also delineate a complex reciprocal relationship between DJ-1 and the Pink1/Parkin pathway of MQC.
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Affiliation(s)
- Alvin P Joselin
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada
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129
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Cho KI, Searle K, Webb M, Yi H, Ferreira PA. Ranbp2 haploinsufficiency mediates distinct cellular and biochemical phenotypes in brain and retinal dopaminergic and glia cells elicited by the Parkinsonian neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Cell Mol Life Sci 2012; 69:3511-27. [PMID: 22821000 PMCID: PMC3445802 DOI: 10.1007/s00018-012-1071-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 06/04/2012] [Accepted: 06/21/2012] [Indexed: 11/25/2022]
Abstract
Many components and pathways transducing multifaceted and deleterious effects of stress stimuli remain ill-defined. The Ran-binding protein 2 (RanBP2) interactome modulates the expression of a range of clinical and cell-context-dependent manifestations upon a variety of stressors. We examined the role of Ranbp2 haploinsufficiency on cellular and metabolic manifestations linked to tyrosine-hydroxylase (TH+) dopaminergic neurons and glial cells of the brain and retina upon acute challenge to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a parkinsonian neurotoxin, which models facets of Parkinson disease. MPTP led to stronger akinetic parkinsonism and slower recovery in Ranbp2+/− than wild-type mice without viability changes of brain TH+-neurons of either genotype, with the exception of transient nuclear atypia via changes in chromatin condensation of Ranbp2+/− TH+-neurons. Conversely, the number of wild-type retinal TH+-amacrine neurons compared to Ranbp2+/− underwent milder declines without apoptosis followed by stronger recoveries without neurogenesis. These phenotypes were accompanied by a stronger rise of EdU+-proliferative cells and non-proliferative gliosis of GFAP+-Müller cells in wild-type than Ranbp2+/− that outlasted the MPTP-insult. Finally, MPTP-treated wild-type and Ranbp2+/− mice present distinct metabolic footprints in the brain or selective regions thereof, such as striatum, that are supportive of RanBP2-mediated regulation of interdependent metabolic pathways of lysine, cholesterol, free-fatty acids, or their β-oxidation. These studies demonstrate contrasting gene-environment phenodeviances and roles of Ranbp2 between dopaminergic and glial cells of the brain and retina upon oxidative stress-elicited signaling and factors triggering a continuum of metabolic and cellular manifestations and proxies linked to oxidative stress, and chorioretinal and neurological disorders such as Parkinson.
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Affiliation(s)
- Kyoung-in Cho
- Department of Ophthalmology, Duke University Medical Center, DUEC 3802, 2351 Erwin Road, Durham, NC 27710 USA
| | - Kelly Searle
- Department of Ophthalmology, Duke University Medical Center, DUEC 3802, 2351 Erwin Road, Durham, NC 27710 USA
- Department of Epidemiology, The Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, 21205 MD
| | - Mason Webb
- Department of Ophthalmology, Duke University Medical Center, DUEC 3802, 2351 Erwin Road, Durham, NC 27710 USA
| | - Haiqing Yi
- Department of Ophthalmology, Duke University Medical Center, DUEC 3802, 2351 Erwin Road, Durham, NC 27710 USA
| | - Paulo A. Ferreira
- Department of Ophthalmology, Duke University Medical Center, DUEC 3802, 2351 Erwin Road, Durham, NC 27710 USA
- Department of Pathology, Duke University Medical Center, Durham, NC 27710 USA
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130
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Mitochondrial dysfunction in Parkinson's disease: molecular mechanisms and pathophysiological consequences. EMBO J 2012; 31:3038-62. [PMID: 22735187 DOI: 10.1038/emboj.2012.170] [Citation(s) in RCA: 411] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 06/01/2012] [Indexed: 12/24/2022] Open
Abstract
Neurons are critically dependent on mitochondrial integrity based on specific morphological, biochemical, and physiological features. They are characterized by high rates of metabolic activity and need to respond promptly to activity-dependent fluctuations in bioenergetic demand. The dimensions and polarity of neurons require efficient transport of mitochondria to hot spots of energy consumption, such as presynaptic and postsynaptic sites. Moreover, the postmitotic state of neurons in combination with their exposure to intrinsic and extrinsic neuronal stress factors call for a high fidelity of mitochondrial quality control systems. Consequently, it is not surprising that mitochondrial alterations can promote neuronal dysfunction and degeneration. In particular, mitochondrial dysfunction has long been implicated in the etiopathogenesis of Parkinson's disease (PD), based on the observation that mitochondrial toxins can cause parkinsonism in humans and animal models. Substantial progress towards understanding the role of mitochondria in the disease process has been made by the identification and characterization of genes causing familial variants of PD. Studies on the function and dysfunction of these genes revealed that various aspects of mitochondrial biology appear to be affected in PD, comprising mitochondrial biogenesis, bioenergetics, dynamics, transport, and quality control.
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131
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Leuner K, Schütt T, Kurz C, Eckert SH, Schiller C, Occhipinti A, Mai S, Jendrach M, Eckert GP, Kruse SE, Palmiter RD, Brandt U, Dröse S, Wittig I, Willem M, Haass C, Reichert AS, Müller WE. Mitochondrion-derived reactive oxygen species lead to enhanced amyloid beta formation. Antioxid Redox Signal 2012; 16:1421-33. [PMID: 22229260 PMCID: PMC3329950 DOI: 10.1089/ars.2011.4173] [Citation(s) in RCA: 236] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
AIMS Intracellular amyloid beta (Aβ) oligomers and extracellular Aβ plaques are key players in the progression of sporadic Alzheimer's disease (AD). Still, the molecular signals triggering Aβ production are largely unclear. We asked whether mitochondrion-derived reactive oxygen species (ROS) are sufficient to increase Aβ generation and thereby initiate a vicious cycle further impairing mitochondrial function. RESULTS Complex I and III dysfunction was induced in a cell model using the respiratory inhibitors rotenone and antimycin, resulting in mitochondrial dysfunction and enhanced ROS levels. Both treatments lead to elevated levels of Aβ. Presence of an antioxidant rescued mitochondrial function and reduced formation of Aβ, demonstrating that the observed effects depended on ROS. Conversely, cells overproducing Aβ showed impairment of mitochondrial function such as comprised mitochondrial respiration, strongly altered morphology, and reduced intracellular mobility of mitochondria. Again, the capability of these cells to generate Aβ was partly reduced by an antioxidant, indicating that Aβ formation was also ROS dependent. Moreover, mice with a genetic defect in complex I, or AD mice treated with a complex I inhibitor, showed enhanced Aβ levels in vivo. INNOVATION We show for the first time that mitochondrion-derived ROS are sufficient to trigger Aβ production in vitro and in vivo. CONCLUSION Several lines of evidence show that mitochondrion-derived ROS result in enhanced amyloidogenic amyloid precursor protein processing, and that Aβ itself leads to mitochondrial dysfunction and increased ROS levels. We propose that starting from mitochondrial dysfunction a vicious cycle is triggered that contributes to the pathogenesis of sporadic AD.
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Affiliation(s)
- Kristina Leuner
- Department of Pharmacology, ZAFES, Biocenter, University of Frankfurt, Frankfurt/Main, Germany.
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132
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Fluazinam targets mitochondrial complex I to induce reactive oxygen species-dependent cytotoxicity in SH-SY5Y cells. Neurochem Int 2012; 60:773-81. [DOI: 10.1016/j.neuint.2012.03.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 03/05/2012] [Accepted: 03/13/2012] [Indexed: 11/17/2022]
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133
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Yoshimoto K, Ueda S, Kitamura Y, Inden M, Hattori H, Ishikawa N, McLean S, Ikegaya H. Administration of rotenone enhanced voluntary alcohol drinking behavior in C57BL/6J mice. Leg Med (Tokyo) 2012; 14:229-38. [PMID: 22546249 DOI: 10.1016/j.legalmed.2012.03.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Revised: 02/13/2012] [Accepted: 03/19/2012] [Indexed: 12/21/2022]
Abstract
Rotenone, a commonly used lipophic pesticide, is a high-affinity mitochondrial complex I inhibitor. The aim of this project is to study the causal relationship between changes of brain monoamine levels and drinking behavior in rotenone-treated mice. In the first experiment, we investigated the effects of acute exposure to rotenone (20 mg/kg, p.o.) on the 8-h time limited-access alcohol drinking behavior and brain monoamine levels in C57BL/6J mice at 0, 2, 8 and 24 h. Dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and 5-hydroxyindoleacetic acid (5HIAA) levels in the nucleus accumbens (ACC), caudate-putamen (C/P) and lateral hypothalamus (LH) of rotenone-treated mice were decreased at 2 and/or 8 h. Rotenone-exposed mice showed a suppression of voluntary alcohol intake at 4 and 8 h, but total daily alcohol intake did not differ significantly between the two groups. The effects of chronic exposure to rotenone (1, 5, 10 and 20 mg/kg, p.o. for 30 days) on the alcohol drinking behavior and monoamine levels of rotenone-exposed mice (10 mg/kg, p.o.) were investigated in the second experiment. The mice treated with rotenone showed increases in alcohol drinking behavior. Levels of DA and 5-HT in the ACC and C/P of chronic rotenone-treated mice were decreased, while the ratios of DOPAC to DA in the ACC and C/P and of 5HIAA to 5-HT in the ACC, C/P and DRN were increased significantly. Tyrosine hydroxylase immunoreactivity of chronic rotenone-treated mice (10 mg/kg, p.o.) slightly were decreased in both the striatum and the substantia nigra. Ethanol and acetaldehyde metabolism was not significantly different between mice treated with rotenone (10 mg/kg, p.o.) and controls. It was suggested that rotenone-treated mice had increased alcohol drinking behavior associated with increases in the DA turnover ratios of ACC and striatum to compensate for the neural degeneration.
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Affiliation(s)
- Kanji Yoshimoto
- Department of Forensic Medicine, Kyoto Prefectural University of Medicine, Kawaramachi, Kamigyo-ku, Kyoto 602-8566, Japan.
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134
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Deshmukh RS, Chaudhary RK, Roy I. Effect of pesticides on the aggregation of mutant huntingtin protein. Mol Neurobiol 2012; 45:405-14. [PMID: 22415443 DOI: 10.1007/s12035-012-8252-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 02/28/2012] [Indexed: 01/08/2023]
Abstract
The classical reports on neurodegeneration concentrate on studying disruption of signalling cascades. Although it is now well recognized that misfolding and aggregation of specific proteins are associated with a majority of these diseases, their role in aggravating the symptoms is not so well understood. Huntington's disease (HD) is a neurodegenerative disorder that results from damage to complex II of mitochondria. In this work, we have studied the effect of mitochondrial complex I inhibitors, viz. 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and rotenone, and complex II inhibitor, viz. 3-nitropropionic acid, on the aggregation of mutant huntingtin (mthtt) protein, whose misfolding and aggregation results in cellular abnormalities characteristic of HD. All three inhibitors were found to accelerate the aggregation of mthtt in vitro, although the amounts of aggregates formed were different in all cases. Thus, apart from their effect on mitochondrial viability, these neurotoxins are capable of interfering with the protein aggregation process and thus, hastening the onset of the disease.
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Affiliation(s)
- Ruhi S Deshmukh
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar, Punjab, 160 062, India
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135
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Breuer ME, Willems PHGM, Russel FGM, Koopman WJH, Smeitink JAM. Modeling mitochondrial dysfunctions in the brain: from mice to men. J Inherit Metab Dis 2012; 35:193-210. [PMID: 21755361 PMCID: PMC3278625 DOI: 10.1007/s10545-011-9375-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 06/20/2011] [Accepted: 06/27/2011] [Indexed: 12/12/2022]
Abstract
The biologist Lewis Thomas once wrote: "my mitochondria comprise a very large proportion of me. I cannot do the calculation, but I suppose there is almost as much of them in sheer dry bulk as there is the rest of me". As humans, or indeed as any mammal, bird, or insect, we contain a specific molecular makeup that is driven by vast numbers of these miniscule powerhouses residing in most of our cells (mature red blood cells notwithstanding), quietly replicating, living independent lives and containing their own DNA. Everything we do, from running a marathon to breathing, is driven by these small batteries, and yet there is evidence that these molecular energy sources were originally bacteria, possibly parasitic, incorporated into our cells through symbiosis. Dysfunctions in these organelles can lead to debilitating, and sometimes fatal, diseases of almost all the bodies' major organs. Mitochondrial dysfunction has been implicated in a wide variety of human disorders either as a primary cause or as a secondary consequence. To better understand the role of mitochondrial dysfunction in human disease, a multitude of pharmacologically induced and genetically manipulated animal models have been developed showing to a greater or lesser extent the clinical symptoms observed in patients with known and unknown causes of the disease. This review will focus on diseases of the brain and spinal cord in which mitochondrial dysfunction has been proven or is suspected and on animal models that are currently used to study the etiology, pathogenesis and treatment of these diseases.
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Affiliation(s)
- Megan E Breuer
- Department of Biochemistry, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
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136
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Axon degeneration in Parkinson's disease. Exp Neurol 2012; 246:72-83. [PMID: 22285449 DOI: 10.1016/j.expneurol.2012.01.011] [Citation(s) in RCA: 332] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 12/08/2011] [Accepted: 01/10/2012] [Indexed: 02/07/2023]
Abstract
Parkinson's disease (PD) is the most common neurodegenerative disease of the basal ganglia. Like other adult-onset neurodegenerative disorders, it is without a treatment that forestalls its chronic progression. Efforts to develop disease-modifying therapies to date have largely focused on the prevention of degeneration of the neuron soma, with the tacit assumption that such approaches will forestall axon degeneration as well. We herein propose that future efforts to develop neuroprotection for PD may benefit from a shift in focus to the distinct mechanisms that underlie axon degeneration. We review evidence from human post-mortem studies, functional neuroimaging, genetic causes of the disease and neurotoxin models that axon degeneration may be the earliest feature of the disease, and it may therefore be the most appropriate target for early intervention. In addition, we present evidence that the molecular mechanisms of degeneration of axons are separate and distinct from those of neuron soma. Progress is being made in understanding these mechanisms, and they provide possible new targets for therapeutic intervention. We also suggest that the potential for axon re-growth in the adult central nervous system has perhaps been underestimated, and it offers new avenues for neurorestoration. In conclusion, we propose that a new focus on the neurobiology of axons, their molecular pathways of degeneration and growth, will offer novel opportunities for neuroprotection and restoration in the treatment of PD and other neurodegenerative diseases.
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137
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Zhou H, Zhang F, Chen SH, Zhang D, Wilson B, Hong JS, Gao HM. Rotenone activates phagocyte NADPH oxidase by binding to its membrane subunit gp91phox. Free Radic Biol Med 2012; 52:303-13. [PMID: 22094225 PMCID: PMC3253173 DOI: 10.1016/j.freeradbiomed.2011.10.488] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 10/18/2011] [Accepted: 10/22/2011] [Indexed: 12/21/2022]
Abstract
Rotenone, a widely used pesticide, reproduces parkinsonism in rodents and associates with increased risk for Parkinson disease. We previously reported that rotenone increased superoxide production by stimulating the microglial phagocyte NADPH oxidase (PHOX). This study identified a novel mechanism by which rotenone activates PHOX. Ligand-binding assay revealed that rotenone directly bound to membrane gp91(phox), the catalytic subunit of PHOX; such binding was inhibited by diphenyleneiodonium, a PHOX inhibitor with a binding site on gp91(phox). Functional studies showed that both membrane and cytosolic subunits were required for rotenone-induced superoxide production in cell-free systems, intact phagocytes, and COS7 cells transfected with membrane subunits (gp91(phox)/p22(phox)) and cytosolic subunits (p67(phox) and p47(phox)). Rotenone-elicited extracellular superoxide release in p47(phox)-deficient macrophages suggested that rotenone enabled activation of PHOX through a p47(phox)-independent mechanism. Increased membrane translocation of p67(phox), elevated binding of p67(phox) to rotenone-treated membrane fractions, and coimmunoprecipitation of p67(phox) and gp91(phox) in rotenone-treated wild-type and p47(phox)-deficient macrophages indicated that p67(phox) played a critical role in rotenone-induced PHOX activation via its direct interaction with gp91(phox). Rac1, a Rho-like small GTPase, enhanced p67(phox)-gp91(phox) interaction; Rac1 inhibition decreased rotenone-elicited superoxide release. In conclusion, rotenone directly interacted with gp91(phox); such an interaction triggered membrane translocation of p67(phox), leading to PHOX activation and superoxide production.
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Affiliation(s)
- Hui Zhou
- Neuropharmacology Section, Laboratory of Toxicology & Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, 27709
| | - Feng Zhang
- Neuropharmacology Section, Laboratory of Toxicology & Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, 27709
| | - Shih-heng Chen
- Neuropharmacology Section, Laboratory of Toxicology & Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, 27709
| | - Dan Zhang
- Neuropharmacology Section, Laboratory of Toxicology & Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, 27709
| | - Belinda Wilson
- Neuropharmacology Section, Laboratory of Toxicology & Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, 27709
| | - Jau-shyong Hong
- Neuropharmacology Section, Laboratory of Toxicology & Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, 27709
| | - Hui-Ming Gao
- Neuropharmacology Section, Laboratory of Toxicology & Pharmacology, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, 27709
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138
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Abstract
Parkinson's disease (PD) is the most common age-related motoric neurodegenerative disease initially described in the 1800's by James Parkinson as the 'Shaking Palsy'. Loss of the neurotransmitter dopamine was recognized as underlying the pathophysiology of the motor dysfunction; subsequently discovery of dopamine replacement therapies brought substantial symptomatic benefit to PD patients. However, these therapies do not fully treat the clinical syndrome nor do they alter the natural history of this disorder motivating clinicians and researchers to further investigate the clinical phenotype, pathophysiology/pathobiology and etiology of this devastating disease. Although the exact cause of sporadic PD remains enigmatic studies of familial and rare toxicant forms of this disorder have laid the foundation for genome wide explorations and environmental studies. The combination of methodical clinical evaluation, systematic pathological studies and detailed genetic analyses have revealed that PD is a multifaceted disorder with a wide-range of clinical symptoms and pathology that include regions outside the dopamine system. One common thread in PD is the presence of intracytoplasmic inclusions that contain the protein, α-synuclein. The presence of toxic aggregated forms of α-synuclein (e.g., amyloid structures) are purported to be a harbinger of subsequent pathology. In fact, PD is both a cerebral amyloid disease and the most common synucleinopathy, that is, diseases that display accumulations of α-synuclein. Here we present our current understanding of PD etiology, pathology, clinical symptoms and therapeutic approaches with an emphasis on misfolded α-synuclein.
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Affiliation(s)
- Timothy R. Mhyre
- Department of Neuroscience, Georgetown University Medical Center, NRB EP08, 3970 Reservoir Road NW, 20057, Washington, DC, USA,
| | - James T. Boyd
- University of Vermont College of Medicine, 1 South Prospect Street, DU-Arnold 4416-UHC, 05401, Burlington, VT, USA,
| | - Robert W. Hamill
- Department of Neurology, University of Vermont College of Medicine, 89 Beaumont Avenue, Given Hall Room C225, 05405, Burlington, VT, USA,
| | - Kathleen A. Maguire-Zeiss
- Department of Neuroscience, Center for Neural Injury and RecoveryGeorgetown University Medical Center, 3970 Reservoir Road, NW NRB EP08, 20057, Washington, DC, USA,
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139
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Uncoupling of ATP-depletion and cell death in human dopaminergic neurons. Neurotoxicology 2011; 33:769-79. [PMID: 22206971 DOI: 10.1016/j.neuro.2011.12.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 12/08/2011] [Indexed: 12/21/2022]
Abstract
The mitochondrial inhibitor 1-methyl-4-phenylpyridinium (MPP(+)) is the toxicologically relevant metabolite of 1-methyl-4-phenyltetrahydropyridine (MPTP), which causes relatively selective degeneration of dopaminergic neurons in the substantia nigra. Dopaminergic LUHMES cells were used to investigate whether ATP-depletion can be uncoupled from cell death as a downstream event in these fully post-mitotic human neurons. Biochemical assays indicated that in the homogeneously differentiated cell cultures, MPP(+) was taken up by the dopamine transporter (DAT). MPP(+) then triggered oxidative stress and caspase activation, as well as ATP-depletion followed by cell death. Enhanced survival of the neurons in the presence of agents interfering with mitochondrial pathology, such as the fission inhibitor Mdivi-1 or a Bax channel blocker suggested a pivotal role of mitochondria in this model. However, these compounds did not prevent cellular ATP-depletion. To further investigate whether cells could be rescued despite respiratory chain inhibition by MPP(+), we have chosen a diverse set of pharmacological inhibitors well-known to interfere with MPP(+) toxicity. The antioxidant ascorbate, the iron chelator desferoxamine, the stress kinase inhibitor CEP1347, and different caspase inhibitors reduced cell death, but allowed ATP-depletion in protected cells. None of these compounds interfered with MPP(+) accumulation in the cells. These findings suggest that ATP-depletion, as the initial mitochondrial effect of MPP(+), requires further downstream processes to result in neuronal death. These processes may form self-enhancing signaling loops, that aggravate an initial energetic impairment and eventually determine cell fate.
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140
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Fluazinam-induced apoptosis of SH-SY5Y cells is mediated by p53 and Bcl-2 family proteins. Neurotoxicology 2011; 32:702-10. [DOI: 10.1016/j.neuro.2011.08.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 07/26/2011] [Accepted: 08/21/2011] [Indexed: 12/25/2022]
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141
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Potts LF, Luzzio FA, Smith SC, Hetman M, Champy P, Litvan I. Annonacin in Asimina triloba fruit: implication for neurotoxicity. Neurotoxicology 2011; 33:53-8. [PMID: 22130466 DOI: 10.1016/j.neuro.2011.10.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 10/25/2011] [Accepted: 10/26/2011] [Indexed: 10/15/2022]
Abstract
INTRODUCTION The acetogenin, annonacin, from the tropical annonaceous plant Annona muricata, is a lipophilic, mitochondrial complex I inhibitor reported to be more toxic than rotenone to mesencephalic neurons. The temperate annonaceous plant Asimina triloba (pawpaw) is native to the Eastern United States and products are available online. This study determined whether annonacin is in the pawpaw fruit pulp and whether it or the crude ethyl acetate extract is toxic to cortical neurons. METHODS Pawpaw extract was prepared by pulp extraction with methanol and liquid-liquid partitioning with ethyl acetate (EtOAc). Annonacin was isolated from the crude EtOAc extract via column chromatography using a gradient solvent system of increasing polarity. Mass spectroscopy, nuclear magnetic resonance and infrared spectroscopy were used to compare isolated material with synthetic annonacin data and a natural annonacin sample. Toxicity of isolated annonacin and the total EtOAc extract was determined in primary rat cortical neurons using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. RESULTS The average concentration of annonacin in the fruit pulp was 0.0701±0.0305mg/g. Purified annonacin (30.07μg/ml) and crude EtOAc extract (47.96μg/ml) induced 50% death of cortical neurons 48h post treatment. Annonacin toxicity was enhanced in the presence of crude extract. DISCUSSION Pawpaw fruit contains a high concentration of annonacin, which is toxic to cortical neurons. Crude fruit extract also induced neurotoxicity, highlighting the need for additional studies to determine the potential risks of neurodegeneration associated with chronic exposure to pawpaw products.
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Affiliation(s)
- Lisa F Potts
- Department of Anatomical Sciences and Neurobiology, University of Louisville, United States
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142
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Sterky FH, Hoffman AF, Milenkovic D, Bao B, Paganelli A, Edgar D, Wibom R, Lupica CR, Olson L, Larsson NG. Altered dopamine metabolism and increased vulnerability to MPTP in mice with partial deficiency of mitochondrial complex I in dopamine neurons. Hum Mol Genet 2011; 21:1078-89. [PMID: 22090423 DOI: 10.1093/hmg/ddr537] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
A variety of observations support the hypothesis that deficiency of complex I [reduced nicotinamide-adenine dinucleotide (NADH):ubiquinone oxidoreductase] of the mitochondrial respiratory chain plays a role in the pathophysiology of Parkinson's disease (PD). However, recent data from a study using mice with knockout of the complex I subunit NADH:ubiquinone oxidoreductase iron-sulfur protein 4 (Ndufs4) has challenged this concept as these mice show degeneration of non-dopamine neurons. In addition, primary dopamine (DA) neurons derived from such mice, reported to lack complex I activity, remain sensitive to toxins believed to act through inhibition of complex I. We tissue-specifically disrupted the Ndufs4 gene in mouse heart and found an apparent severe deficiency of complex I activity in disrupted mitochondria, whereas oxidation of substrates that result in entry of electrons at the level of complex I was only mildly reduced in intact isolated heart mitochondria. Further analyses of detergent-solubilized mitochondria showed the mutant complex I to be unstable but capable of forming supercomplexes with complex I enzyme activity. The loss of Ndufs4 thus causes only a mild complex I deficiency in vivo. We proceeded to disrupt Ndufs4 in midbrain DA neurons and found no overt neurodegeneration, no loss of striatal innervation and no symptoms of Parkinsonism in tissue-specific knockout animals. However, DA homeostasis was abnormal with impaired DA release and increased levels of DA metabolites. Furthermore, Ndufs4 DA neuron knockouts were more vulnerable to the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Taken together, these findings lend in vivo support to the hypothesis that complex I deficiency can contribute to the pathophysiology of PD.
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Affiliation(s)
- Fredrik H Sterky
- Department of Laboratory Medicine, Karolinska Institutet, Retzius väg 8, SE-17177 Stockholm, Sweden
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143
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Akashi S, Kimura T, Takeuchi T, Kuramochi K, Kobayashi S, Sugawara F, Watanabe N, Arai T. Neoechinulin a impedes the progression of rotenone-induced cytotoxicity in PC12 cells. Biol Pharm Bull 2011; 34:243-8. [PMID: 21415535 DOI: 10.1248/bpb.34.243] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Neoechinulin A, an indole alkaloid from marine fungi, can protect PC12 cells from the cytotoxicity of 1-methyl-4-phenylpyridinium (MPP(+)), a Parkinson disease-inducing neurotoxin, by ameliorating downstream events resulting from mitochondrial complex I inactivation. However, the cytoprotective mechanisms remained unclear. In this study, by using rotenone, another parkinsonian-inducing neurotoxin targeting mitochondrial complex I, we investigated the cytoprotective mechanism of neoechinulin A. Rotenone-induced cell death was associated with accelerated glucose consumption, and excess glucose supplementation in the culture medium almost completely suppressed cell death, suggesting that glucose deficiency in the medium is critical for triggering cell death in this model. Co-treatment with neoechinulin A, but not neoechinulin A pre-treatment before rotenone exposure, significantly impeded cell death by rotenone. Although the presence of neoechinulin A did not affect the accelerated glycolytic turnover in rotenone-treated cells, it paradoxically decreased ATP levels in the cells, suggesting increased ATP consumption. Although the link between the decreased ATP levels and cytoprotection is not clear at present, it suggests that neoechinulin A may ameliorate rotenone toxicity by activating a cytoprotective machinery that requires ATP.
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Affiliation(s)
- Soichiro Akashi
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Tokyo University of Science; 2641 Yamazaki, Noda, Chiba 278–8510, Japan
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144
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Basu SS, Blair IA. Rotenone-mediated changes in intracellular coenzyme A thioester levels: implications for mitochondrial dysfunction. Chem Res Toxicol 2011; 24:1630-2. [PMID: 21950265 PMCID: PMC3196242 DOI: 10.1021/tx200366j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Indexed: 02/06/2023]
Abstract
Rotenone, an organic pesticide and potent mitochondrial complex I inhibitor, causes Parkinson-like neurodegeneration in rodents and is implicated in human Parkinson's disease. In this rapid report, rotenone induced a dose-dependent decrease in succinyl-coenzyme A (CoA) and increase in β-hydroxybutyryl-CoA in multiple human cell lines (IC(50) < 100 nM). Rotenone also inhibited [U-(13)C(6)]-glucose-derived [(13)C]-acetyl-CoA and [(13)C]-succinyl-CoA biosynthesis in SH-SY5Y neuroblastoma cells. These changes are compatible with a compensatory metabolic rearrangement. Stable isotope dilution liquid chromatography-mass spectrometry and CoA thioester isotopomer analysis provided insight into mechanisms of rotenone toxicity, which will facilitate the development of new biomarkers of mitochondrial dysfunction.
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Affiliation(s)
- Sankha S. Basu
- Centers for Cancer Pharmacology and Excellence in Environmental Toxicology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104-6160, United States
| | - Ian A. Blair
- Centers for Cancer Pharmacology and Excellence in Environmental Toxicology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104-6160, United States
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145
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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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146
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Saxena S, Caroni P. Selective neuronal vulnerability in neurodegenerative diseases: from stressor thresholds to degeneration. Neuron 2011; 71:35-48. [PMID: 21745636 DOI: 10.1016/j.neuron.2011.06.031] [Citation(s) in RCA: 389] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/27/2011] [Indexed: 12/12/2022]
Abstract
Neurodegenerative diseases selectively target subpopulations of neurons, leading to the progressive failure of defined brain systems, but the basis of such selective neuronal vulnerability has remained elusive. Here, we discuss how a stressor-threshold model of how particular neurons and circuits are selectively vulnerable to disease may underly the etiology of familial and sporadic forms of diseases such as Alzheimer's, Parkinson's, Huntington's, and ALS. According to this model, the intrinsic vulnerabilities of neuronal subpopulations to stressors and specific disease-related misfolding proteins determine neuronal morbidity. Neurodegenerative diseases then involve specific combinations of genetic predispositions and environmental stressors, triggering increasing age-related stress and proteostasis dysfunction in affected vulnerable neurons. Damage to vasculature, immune system, and local glial cells mediates environmental stress, which could drive disease at all stages.
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Affiliation(s)
- Smita Saxena
- Friedrich Miescher Institut, Novartis Research Foundation, CH-4058 Basel, Switzerland
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147
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Synergistic growth inhibition of cancer cells harboring the RET/PTC1 oncogene by staurosporine and rotenone involves enhanced cell death. J Biosci 2011; 36:639-48. [DOI: 10.1007/s12038-011-9100-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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148
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Stoll EA, Cheung W, Mikheev AM, Sweet IR, Bielas JH, Zhang J, Rostomily RC, Horner PJ. Aging neural progenitor cells have decreased mitochondrial content and lower oxidative metabolism. J Biol Chem 2011; 286:38592-38601. [PMID: 21900249 DOI: 10.1074/jbc.m111.252171] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although neurogenesis occurs in discrete areas of the adult mammalian brain, neural progenitor cells (NPCs) produce fewer new neurons with age. To characterize the molecular changes that occur during aging, we performed a proteomic comparison between primary-cultured NPCs from the young adult and aged mouse forebrain. This analysis yielded changes in proteins necessary for cellular metabolism. Mitochondrial quantity and oxygen consumption rates decrease with aging, although mitochondrial DNA in aged NPCs does not have increased mutation rates. In addition, aged cells are resistant to the mitochondrial inhibitor rotenone and proliferate in response to lowered oxygen conditions. These results demonstrate that aging NPCs display an altered metabolic phenotype, characterized by a coordinated shift in protein expression, subcellular structure, and metabolic physiology.
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Affiliation(s)
- Elizabeth A Stoll
- Neurobiology and Behavior Program, University of Washington, Seattle, Washington 98109
| | - Willy Cheung
- Department of Computer Science, University of Washington, Seattle, Washington 98109
| | - Andrei M Mikheev
- Department of Neurological Surgery, University of Washington, Seattle, Washington 98109
| | - Ian R Sweet
- Department of Medicine, University of Washington, Seattle, Washington 98109; Diabetes Endocrine Research Center, University of Washington, Seattle, Washington 98109
| | - Jason H Bielas
- Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, University of Washington, Seattle, Washington 98109; Department of Pathology, University of Washington, Seattle, Washington 98109
| | - Jing Zhang
- Department of Pathology, University of Washington, Seattle, Washington 98109
| | - Robert C Rostomily
- Department of Neurological Surgery, University of Washington, Seattle, Washington 98109
| | - Philip J Horner
- Neurobiology and Behavior Program, University of Washington, Seattle, Washington 98109; Department of Neurological Surgery, University of Washington, Seattle, Washington 98109.
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149
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Choi WS, Palmiter RD, Xia Z. Loss of mitochondrial complex I activity potentiates dopamine neuron death induced by microtubule dysfunction in a Parkinson's disease model. ACTA ACUST UNITED AC 2011; 192:873-82. [PMID: 21383081 PMCID: PMC3051820 DOI: 10.1083/jcb.201009132] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The combination of microtubule depolymerization and the accumulation of cytosolic dopamine and reactive oxygen species selectively affects survival of dopaminergic neurons. Mitochondrial complex I dysfunction is regarded as underlying dopamine neuron death in Parkinson’s disease models. However, inactivation of the Ndufs4 gene, which compromises complex I activity, does not affect the survival of dopamine neurons in culture or in the substantia nigra pars compacta of 5-wk-old mice. Treatment with piericidin A, a complex I inhibitor, does not induce selective dopamine neuron death in either Ndufs4+/+ or Ndufs4−/− mesencephalic cultures. In contrast, rotenone, another complex I inhibitor, causes selective toxicity to dopamine neurons, and Ndufs4 inactivation potentiates this toxicity. We identify microtubule depolymerization and the accumulation of cytosolic dopamine and reactive oxygen species as alternative mechanisms underlying rotenone-induced dopamine neuron death. Enhanced rotenone toxicity to dopamine neurons from Ndufs4 knockout mice may involve enhanced dopamine synthesis caused by the accumulation of nicotinamide adenine dinucleotide reduced. Our results suggest that the combination of disrupting microtubule dynamics and inhibiting complex I, either by mutations or exposure to toxicants, may be a risk factor for Parkinson’s disease.
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Affiliation(s)
- Won-Seok Choi
- Department of Environmental and Occupational Health Sciences, Graduate Program in Neurobiology and Behavior, University of Washington, Seattle, WA 98195, USA
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150
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Wimalasena K. Vesicular monoamine transporters: structure-function, pharmacology, and medicinal chemistry. Med Res Rev 2011; 31:483-519. [PMID: 20135628 PMCID: PMC3019297 DOI: 10.1002/med.20187] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Vesicular monoamine transporters (VMAT) are responsible for the uptake of cytosolic monoamines into synaptic vesicles in monoaminergic neurons. Two closely related VMATs with distinct pharmacological properties and tissue distributions have been characterized. VMAT1 is preferentially expressed in neuroendocrine cells and VMAT2 is primarily expressed in the CNS. The neurotoxicity and addictive properties of various psychostimulants have been attributed, at least partly, to their interference with VMAT2 functions. The quantitative assessment of the VMAT2 density by PET scanning has been clinically useful for early diagnosis and monitoring of the progression of Parkinson's and Alzheimer's diseases and drug addiction. The classical VMAT2 inhibitor, tetrabenazine, has long been used for the treatment of chorea associated with Huntington's disease in the United Kingdom, Canada, and Australia, and recently approved in the United States. The VMAT2 imaging may also be useful for exploiting the onset of diabetes mellitus, as VMAT2 is also expressed in the β-cells of the pancreas. VMAT1 gene SLC18A1 is a locus with strong evidence of linkage with schizophrenia and, thus, the polymorphic forms of the VMAT1 gene may confer susceptibility to schizophrenia. This review summarizes the current understanding of the structure-function relationships of VMAT2, and the role of VMAT2 on addiction and psychostimulant-induced neurotoxicity, and the therapeutic and diagnostic applications of specific VMAT2 ligands. The evidence for the linkage of VMAT1 gene with schizophrenia and bipolar disorder I is also discussed.
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