1
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Differential ROS-Mediated Phosphorylation of Drp1 in Mitochondrial Fragmentation Induced by Distinct Cell Death Conditions in Cerebellar Granule Neurons. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:8832863. [PMID: 33936388 PMCID: PMC8060094 DOI: 10.1155/2021/8832863] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 01/08/2021] [Accepted: 03/18/2021] [Indexed: 12/21/2022]
Abstract
Reactive oxygen species (ROS) production has been associated with neuronal death. ROS are also involved in mitochondrial fission, which is mediated by Dynamin-related protein 1 (Drp1). The regulation of mitochondrial fragmentation mediated by Drp1 and its relationship to mitochondrial ROS (mtROS) in neuronal death have not been completely clarified. The aim of this study is to evaluate the role of mtROS in cell death and their involvement in the activation of Drp1 and mitochondrial fission in a model of cell death of cultured cerebellar granule neurons (CGN). Neuronal death of CGN induced by potassium deprivation (K5) and staurosporine (ST) triggers mitochondrial ROS production and mitochondrial fragmentation. K5 condition evoked an increase of Drp1 phosphorylation at Ser616, but ST treatment led to a decrease of Drp1 phosphorylation. Moreover, the death of CGN induced by both K5 and ST was markedly reduced in the presence of MitoTEMPO; however, mitochondrial morphology was not recovered. Here, we show that the mitochondria are the initial source of ROS involved in the neuronal death of CGN and that mitochondrial fragmentation is a common event in cell death; however, this process is not mediated by Drp1 phosphorylation at Ser616.
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2
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Sharipov RR, Krasilnikova IA, Pinelis VG, Gorbacheva LR, Surin AM. Study of the Mechanism of the Neuron Sensitization to the Repeated Glutamate Challenge. BIOCHEMISTRY MOSCOW SUPPLEMENT SERIES A-MEMBRANE AND CELL BIOLOGY 2018. [DOI: 10.1134/s1990747818050057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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3
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Laaper M, Haque T, Slack RS, Jahani-Asl A. Modeling Neuronal Death and Degeneration in Mouse Primary Cerebellar Granule Neurons. J Vis Exp 2017. [PMID: 29155785 DOI: 10.3791/55871] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Cerebellar granule neurons (CGNs) are a commonly used neuronal model, forming an abundant homogeneous population in the cerebellum. In light of their post-natal development, abundance, and accessibility, CGNs are an ideal model to study neuronal processes, including neuronal development, neuronal migration, and physiological neuronal activity stimulation. In addition, CGN cultures provide an excellent model for studying different modes of cell death including excitotoxicity and apoptosis. Within a week in culture, CGNs express N-methyl-D-aspartate (NMDA) receptors, a specific ionotropic glutamate receptor with many critical functions in neuronal health and disease. The addition of low concentrations of NMDA in conjunction with membrane depolarization to rodent primary CGN cultures has been used to model physiological neuronal activity stimulation while the addition of high concentrations of NMDA can be employed to model excitotoxic neuronal injury. Here, a method of isolation and culturing of CGNs from 6 day old pups as well as genetic manipulation of CGNs by adenoviruses and lentiviruses are described. We also present optimized protocols on how to stimulate NMDA-induced excitotoxicity, low-potassium-induced apoptosis, oxidative stress and DNA damage following transduction of these neurons.
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Affiliation(s)
- Matthew Laaper
- Lady Davis Institute for Medical Research, Jewish General Hospital; Integrated Program in Neuroscience, McGill University
| | - Takrima Haque
- Lady Davis Institute for Medical Research, Jewish General Hospital
| | - Ruth S Slack
- Department of Cellular and Molecular Medicine, University of Ottawa
| | - Arezu Jahani-Asl
- Lady Davis Institute for Medical Research, Jewish General Hospital; Integrated Program in Neuroscience, McGill University; Department of Oncology, Faculty of Medicine, McGill University;
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4
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Jiajia L, Shinghung M, Jiacheng Z, Jialing W, Dilin X, Shengquan H, Zaijun Z, Qinwen W, Yifan H, Wei C. Assessment of Neuronal Viability Using Fluorescein Diacetate-Propidium Iodide Double Staining in Cerebellar Granule Neuron Culture. J Vis Exp 2017. [PMID: 28518109 DOI: 10.3791/55442] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Primary cultured Cerebellar Granule Neurons (CGNs) have been widely used as an in vitro model in neuroscience and neuropharmacology research. However, the co-existence of glial cells and neurons in CGN culture might lead to biases in the accurate assessment of neuronal viability. Fluorescein diacetate (FDA) and Propidium Iodide (PI) double staining has been used to measure cell viability by simultaneously evaluating the viable and dead cells. We used FDA-PI double staining to improve the sensitivities of the colorimetric assays and to evaluate neuronal viability in CGNs. Furthermore, we added blue fluorescent DNA stains (e.g., Hoechst) to improve the accuracy. This protocol describes how to improve the accuracy of assessment of neuronal viability by using these methods in CGN culture. Using this protocol, the number of glial cells can be excluded by using fluorescence microscopy. A similar strategy can be applied to distinguish the unwanted glial cells from neurons in various mixed cell cultures, such as primary cortical culture and hippocampal culture.
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Affiliation(s)
- Lin Jiajia
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University
| | - Mak Shinghung
- Department of Applied Biology and Chemistry Technology, Institute of Modern Chinese Medicine, The Hong Kong Polytechnic University
| | - Zheng Jiacheng
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University
| | - Wang Jialing
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University
| | - Xu Dilin
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University
| | - Hu Shengquan
- Department of Applied Biology and Chemistry Technology, Institute of Modern Chinese Medicine, The Hong Kong Polytechnic University
| | - Zhang Zaijun
- Institute of New Drug Research, Guangdong Provincial Key Laboratory of Pharmacodynamic, Constituents of Traditional Chinese Medicine & New Drug Research, College of Pharmacy, Jinan University
| | - Wang Qinwen
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University
| | - Han Yifan
- Department of Applied Biology and Chemistry Technology, Institute of Modern Chinese Medicine, The Hong Kong Polytechnic University; International Joint Laboratory (SYSU-PolyU HK) of Novel Anti-Dementia Drugs of Guangdong
| | - Cui Wei
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University; Department of Applied Biology and Chemistry Technology, Institute of Modern Chinese Medicine, The Hong Kong Polytechnic University;
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5
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Oxaloacetate and adipose stromal cells-conditional medium synergistically protected potassium/serum deprivation-induced neuronal apoptosis. Brain Res Bull 2016; 128:7-12. [PMID: 27816553 DOI: 10.1016/j.brainresbull.2016.11.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 10/17/2016] [Accepted: 11/01/2016] [Indexed: 11/21/2022]
Abstract
Adipose stromal cells conditioned media (ASC-CM) protect neurons in a variety of neuronal death models including potassium/serum deprivation-induced neuronal apoptosis. In this study, we found that ASC-CM contained glutamate oxaloacetate transaminase and its substrate, oxaloacetate (OAA) directly protected cerebellar granule neurons (CGN) from apoptosis induced by serum and potassium deprivation. Additionally, OAA inhibited serum and potassium deprivation-induced caspase 3 activation. ASC-CM and OAA in combination had a synergistic neuroprotective effect. Clearly, different from ASC-CM-induced neuroprotection, OAA-induced neuroprotection was Akt- independent but JNK-dependent. These data establish a mechanistic basis supporting that the application of ASC-CM for neuroprotective treatments could be significantly enhanced by addition of OAA.
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6
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Cheng H, Qiu X, Zhao X, Meng W, Huo D, Wei H. Functional Nucleic Acid Probe for Parallel Monitoring K+ and Protoporphyrin IX in Living Organisms. Anal Chem 2016; 88:2937-43. [DOI: 10.1021/acs.analchem.5b04936] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hanjun Cheng
- Department
of Biomedical Engineering, College of Engineering and Applied Sciences,
Collaborative Innovation Center of Chemistry for Life Sciences, Nanjing National Laboratory of Microstructures, Nanjing, Jiangsu 210093, China
- State
Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing 210093, China
| | - Xuefeng Qiu
- Department
of Urology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, Jiangsu 210008, China
| | - Xiaozhi Zhao
- Department
of Urology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, Jiangsu 210008, China
| | - Wei Meng
- School
of Physics, Collaborative Innovation Center of Advanced Microstructures,
Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing, Jiangsu 210093, China
| | - Da Huo
- Department
of Biomedical Engineering, College of Engineering and Applied Sciences,
Collaborative Innovation Center of Chemistry for Life Sciences, Nanjing National Laboratory of Microstructures, Nanjing, Jiangsu 210093, China
| | - Hui Wei
- Department
of Biomedical Engineering, College of Engineering and Applied Sciences,
Collaborative Innovation Center of Chemistry for Life Sciences, Nanjing National Laboratory of Microstructures, Nanjing, Jiangsu 210093, China
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7
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Gebril HM, Avula B, Wang YH, Khan IA, Jekabsons MB. (13)C metabolic flux analysis in neurons utilizing a model that accounts for hexose phosphate recycling within the pentose phosphate pathway. Neurochem Int 2015; 93:26-39. [PMID: 26723542 DOI: 10.1016/j.neuint.2015.12.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 12/16/2015] [Accepted: 12/18/2015] [Indexed: 11/25/2022]
Abstract
Glycolysis, mitochondrial substrate oxidation, and the pentose phosphate pathway (PPP) are critical for neuronal bioenergetics and oxidation-reduction homeostasis, but quantitating their fluxes remains challenging, especially when processes such as hexose phosphate (i.e., glucose/fructose-6-phosphate) recycling in the PPP are considered. A hexose phosphate recycling model was developed which exploited the rates of glucose consumption, lactate production, and mitochondrial respiration to infer fluxes through the major glucose consuming pathways of adherent cerebellar granule neurons by replicating [(13)C]lactate labeling from metabolism of [1,2-(13)C2]glucose. Flux calculations were predicated on a steady-state system with reactions having known stoichiometries and carbon atom transitions. Non-oxidative PPP activity and consequent hexose phosphate recycling, as well as pyruvate production by cytoplasmic malic enzyme, were optimized by the model and found to account for 28 ± 2% and 7.7 ± 0.2% of hexose phosphate and pyruvate labeling, respectively. From the resulting fluxes, 52 ± 6% of glucose was metabolized by glycolysis, compared to 19 ± 2% by the combined oxidative/non-oxidative pentose cycle that allows for hexose phosphate recycling, and 29 ± 8% by the combined oxidative PPP/de novo nucleotide synthesis reactions. By extension, 62 ± 6% of glucose was converted to pyruvate, the metabolism of which resulted in 16 ± 1% of glucose oxidized by mitochondria and 46 ± 6% exported as lactate. The results indicate a surprisingly high proportion of glucose utilized by the pentose cycle and the reactions synthesizing nucleotides, and exported as lactate. While the in vitro conditions to which the neurons were exposed (high glucose, no lactate or other exogenous substrates) limit extrapolating these results to the in vivo state, the approach provides a means of assessing a number of metabolic fluxes within the context of hexose phosphate recycling in the PPP from a minimal set of measurements.
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Affiliation(s)
- Hoda M Gebril
- Department of Biology, Shoemaker Hall, University of Mississippi, University, MS 38677, USA.
| | - Bharathi Avula
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, MS 38677, USA.
| | - Yan-Hong Wang
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, MS 38677, USA.
| | - Ikhlas A Khan
- Department of Biomedical Sciences and National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, MS 38677, USA.
| | - Mika B Jekabsons
- Department of Biology, Shoemaker Hall, University of Mississippi, University, MS 38677, USA.
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8
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Sahdeo S, Tomilov A, Komachi K, Iwahashi C, Datta S, Hughes O, Hagerman P, Cortopassi G. High-throughput screening of FDA-approved drugs using oxygen biosensor plates reveals secondary mitofunctional effects. Mitochondrion 2014; 17:116-25. [PMID: 25034306 DOI: 10.1016/j.mito.2014.07.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 06/11/2014] [Accepted: 07/01/2014] [Indexed: 10/25/2022]
Abstract
Repurposing of FDA-approved drugs with effects on mitochondrial function might shorten the critical path to mitochondrial disease drug development. We improved a biosensor-based assay of mitochondrial O2 consumption, and identified mitofunctional defects in cell models of LHON and FXTAS. Using this platform, we screened a 1600-compound library of clinically used drugs. The assay identified drugs known to affect mitochondrial function, such as metformin and decoquinate. We also identified several drugs not previously known to affect mitochondrial respiration including acarbose, metaraminol, gallamine triethiodide, and acamprosate. These previously unknown 'mitoactives' represent novel links to targets for mitochondrial regulation and potentially therapy, for mitochondrial disease.
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Affiliation(s)
- Sunil Sahdeo
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, 1089 Veterinary Medicine Drive, Davis, CA 95616, United States
| | - Alexey Tomilov
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, 1089 Veterinary Medicine Drive, Davis, CA 95616, United States
| | - Kelly Komachi
- Eon Research, 707 4th Street, Suite 305, Davis, CA 95616, United States
| | - Christine Iwahashi
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, 4455 Tupper Hall, Davis, CA 95616, United States
| | - Sandipan Datta
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, 1089 Veterinary Medicine Drive, Davis, CA 95616, United States
| | - Owen Hughes
- Eon Research, 707 4th Street, Suite 305, Davis, CA 95616, United States
| | - Paul Hagerman
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, 4455 Tupper Hall, Davis, CA 95616, United States
| | - Gino Cortopassi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, 1089 Veterinary Medicine Drive, Davis, CA 95616, United States
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9
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Abstract
Intracellular calcium dynamics is critical for many functions of cerebellar granule cells (GrCs) including membrane excitability, synaptic plasticity, apoptosis, and regulation of gene transcription. Recent measurements of calcium responses in GrCs to depolarization and synaptic stimulation reveal spatial compartmentalization and heterogeneity within dendrites of these cells. However, the main determinants of local calcium dynamics in GrCs are still poorly understood. One reason is that there have been few published studies of calcium dynamics in intact GrCs in their native environment. In the absence of complete information, biophysically realistic models are useful for testing whether specific Ca(2+) handling mechanisms may account for existing experimental observations. Simulation results can be used to identify critical measurements that would discriminate between different models. In this review, we briefly describe experimental studies and phenomenological models of Ca(2+) signaling in GrC, and then discuss a particular biophysical model, with a special emphasis on an approach for obtaining information regarding the distribution of Ca(2+) handling systems under conditions of incomplete experimental data. Use of this approach suggests that Ca(2+) channels and fixed endogenous Ca(2+) buffers are highly heterogeneously distributed in GrCs. Research avenues for investigating calcium dynamics in GrCs by a combination of experimental and modeling studies are proposed.
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Affiliation(s)
- Elena È Saftenku
- Department of General Physiology of Nervous System, A. A. Bogomoletz Institute of Physiology, 4 Bogomoletz St., Kyiv 01024, Ukraine.
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10
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Samhan-Arias AK, Marques-da-Silva D, Yanamala N, Gutierrez-Merino C. Stimulation and clustering of cytochrome b5 reductase in caveolin-rich lipid microdomains is an early event in oxidative stress-mediated apoptosis of cerebellar granule neurons. J Proteomics 2011; 75:2934-49. [PMID: 22200675 DOI: 10.1016/j.jprot.2011.12.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 12/06/2011] [Accepted: 12/10/2011] [Indexed: 12/30/2022]
Abstract
The apoptosis of cerebellar granule neurons (CGN) induced by low potassium in the extracellular medium is a model of neuronal apoptosis where an overshot of reactive oxygen species (ROS) triggers the neuronal death. In this work, using dihydroethidium and L-012 as specific dyes for superoxide anion detection we show that this ROS overshot can be accounted by an increased release of superoxide anion to the extracellular medium. The amplitude and time course of the increase of superoxide anion observed early during apoptosis correlated with the increase of the content of soluble cytochrome b(5), a substrate of the NADH-dependent oxidase activity of the cytochrome b(5) reductase associated with lipid rafts in CGN. Western blotting and immunofluorescence microscopy approaches, including fluorescence energy transfer, pointed out an enhanced clustering of cytochrome b(5) reductase within caveolins-rich lipid rafts microdomains. Protein/protein docking analysis suggests that cytochrome b(5) reductase can form complexes with caveolins 1α, 1β and 2, playing electrostatic interactions a major role in this association. In conclusion, our results indicate that overstimulation of cytochrome b(5) reductase associated with lipid rafts can account for the overshot of plasma membrane-focalized superoxide anion production that triggers the entry of CGN in the irreversible phase of apoptosis. This article is part of a Special Issue entitled: Proteomics: The clinical link.
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Affiliation(s)
- Alejandro K Samhan-Arias
- Dept. Biochemistry and Molecular Biology, Faculty of Sciences, University of Extremadura, 06006 - Badajoz, Spain
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11
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Abstract
Assessing mitochondrial dysfunction requires definition of the dysfunction to be investigated. Usually, it is the ability of the mitochondria to make ATP appropriately in response to energy demands. Where other functions are of interest, tailored solutions are required. Dysfunction can be assessed in isolated mitochondria, in cells or in vivo, with different balances between precise experimental control and physiological relevance. There are many methods to measure mitochondrial function and dysfunction in these systems. Generally, measurements of fluxes give more information about the ability to make ATP than do measurements of intermediates and potentials. For isolated mitochondria, the best assay is mitochondrial respiratory control: the increase in respiration rate in response to ADP. For intact cells, the best assay is the equivalent measurement of cell respiratory control, which reports the rate of ATP production, the proton leak rate, the coupling efficiency, the maximum respiratory rate, the respiratory control ratio and the spare respiratory capacity. Measurements of membrane potential provide useful additional information. Measurement of both respiration and potential during appropriate titrations enables the identification of the primary sites of effectors and the distribution of control, allowing deeper quantitative analyses. Many other measurements in current use can be more problematic, as discussed in the present review.
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12
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Schuh RA, Clerc P, Hwang H, Mehrabian Z, Bittman K, Chen H, Polster BM. Adaptation of microplate-based respirometry for hippocampal slices and analysis of respiratory capacity. J Neurosci Res 2011; 89:1979-88. [PMID: 21520220 DOI: 10.1002/jnr.22650] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 03/01/2011] [Accepted: 03/01/2011] [Indexed: 01/09/2023]
Abstract
Multiple neurodegenerative disorders are associated with altered mitochondrial bioenergetics. Although mitochondrial O(2) consumption is frequently measured in isolated mitochondria, isolated synaptic nerve terminals (synaptosomes), or cultured cells, the absence of mature brain circuitry is a remaining limitation. Here we describe the development of a method that adapts the Seahorse Extracellular Flux Analyzer (XF24) for the microplate-based measurement of hippocampal slice O(2) consumption. As a first evaluation of the technique, we compared whole-slice bioenergetics with previous measurements made with synaptosomes or cultured neurons. We found that mitochondrial respiratory capacity and O(2) consumption coupled to ATP synthesis could be estimated in cultured or acute hippocampal slices with preserved neural architecture. Mouse organotypic hippocampal slices oxidizing glucose displayed mitochondrial O(2) consumption that was well coupled, as determined by the sensitivity to the ATP synthase inhibitor oligomycin. However, stimulation of respiration by uncoupler was modest (<120% of basal respiration) compared with previous measurements in cells or synaptosomes, though enhanced slightly (to ∼150% of basal respiration) by acute addition of the mitochondrial complex I-linked substrate pyruvate. These findings suggest a high basal utilization of respiratory capacity in slices and a limitation of glucose-derived substrate for maximal respiration. The improved throughput of microplate-based hippocampal respirometry over traditional O(2) electrode-based methods is conducive to neuroprotective drug screening. When coupled with cell type-specific pharmacology or genetic manipulations, the ability to measure O(2) consumption efficiently from whole slices should advance our understanding of mitochondrial roles in physiology and neuropathology.
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Affiliation(s)
- Rosemary A Schuh
- Research Service, Maryland VA Healthcare System, Baltimore, Maryland, USA
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13
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Abstract
Two principal pathways exist by which cells can undergo apoptotic death, known as the extrinsic and the intrinsic pathways. Binding of a ligand to a death receptor activates the extrinsic pathway. In the intrinsic pathway, an apoptotic stimulus, such as neurotrophin withdrawal or exposure to a toxin, causes a proapoptotic member of the Bcl-2 family of proteins, such as Bax, to permeabilize the outer mitochondrial membrane. This allows redistribution of cytochrome c from the mitochondrial intermembrane space into the cytoplasm, where it causes activation of caspase proteases and, subsequently, cell death. A dramatic increase occurs in mitochondria-derived reactive oxygen species (ROS) during the apoptotic death of sympathetic, cerebellar granule, and cortical neurons. These ROS lie downstream of Bax in each cell type. Here I review possible mechanisms by which Bax causes increased ROS during neuronal apoptosis. I also discuss evidence that these ROS are an important part of the apoptotic cascade in these cells. Finally, I discuss evidence that suggests that neurotrophins prevent release of cytochrome c in neurons through activation of an antioxidant pathway.
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Affiliation(s)
- James L Franklin
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 Green St., Athens, GA 30602, USA.
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14
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Isaev NK, Stelmashook EV, Dirnagl U, Plotnikov EY, Kuvshinova EA, Zorov DB. Mitochondrial free radical production induced by glucose deprivation in cerebellar granule neurons. BIOCHEMISTRY (MOSCOW) 2011; 73:149-55. [DOI: 10.1134/s0006297908020053] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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15
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Morgan JB, Mahdi F, Liu Y, Coothankandaswamy V, Jekabsons MB, Johnson TA, Sashidhara KV, Crews P, Nagle DG, Zhou YD. The marine sponge metabolite mycothiazole: a novel prototype mitochondrial complex I inhibitor. Bioorg Med Chem 2010; 18:5988-94. [PMID: 20637638 DOI: 10.1016/j.bmc.2010.06.072] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Revised: 06/18/2010] [Accepted: 06/21/2010] [Indexed: 11/24/2022]
Abstract
A natural product chemistry-based approach was applied to discover small-molecule inhibitors of hypoxia-inducible factor-1 (HIF-1). A Petrosaspongia mycofijiensis marine sponge extract yielded mycothiazole (1), a solid tumor selective compound with no known mechanism for its cell line-dependent cytotoxic activity. Compound 1 inhibited hypoxic HIF-1 signaling in tumor cells (IC(50) 1nM) that correlated with the suppression of hypoxia-stimulated tumor angiogenesis in vitro. However, 1 exhibited pronounced neurotoxicity in vitro. Mechanistic studies revealed that 1 selectively suppresses mitochondrial respiration at complex I (NADH-ubiquinone oxidoreductase). Unlike rotenone, MPP(+), annonaceous acetogenins, piericidin A, and other complex I inhibitors, mycothiazole is a mixed polyketide/peptide-derived compound with a central thiazole moiety. The exquisite potency and structural novelty of 1 suggest that it may serve as a valuable molecular probe for mitochondrial biology and HIF-mediated hypoxic signaling.
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Affiliation(s)
- J Brian Morgan
- Department of Pharmacognosy, School of Pharmacy, University of Mississippi, University, MS 38677, USA
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16
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Brand MD. The sites and topology of mitochondrial superoxide production. Exp Gerontol 2010; 45:466-72. [PMID: 20064600 DOI: 10.1016/j.exger.2010.01.003] [Citation(s) in RCA: 796] [Impact Index Per Article: 56.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2009] [Revised: 12/21/2009] [Accepted: 01/06/2010] [Indexed: 01/12/2023]
Abstract
Mitochondrial superoxide production is an important source of reactive oxygen species in cells, and may cause or contribute to ageing and the diseases of ageing. Seven major sites of superoxide production in mammalian mitochondria are known and widely accepted. In descending order of maximum capacity they are the ubiquinone-binding sites in complex I (site IQ) and complex III (site IIIQo), glycerol 3-phosphate dehydrogenase, the flavin in complex I (site IF), the electron transferring flavoprotein:Q oxidoreductase (ETFQOR) of fatty acid beta-oxidation, and pyruvate and 2-oxoglutarate dehydrogenases. None of these sites is fully characterized and for some we only have sketchy information. The topology of the sites is important because it determines whether or not a site will produce superoxide in the mitochondrial matrix and be able to damage mitochondrial DNA. All sites produce superoxide in the matrix; site IIIQo and glycerol 3-phosphate dehydrogenase also produce superoxide to the intermembrane space. The relative contribution of each site to mitochondrial reactive oxygen species generation in the absence of electron transport inhibitors is unknown in isolated mitochondria, in cells or in vivo, and may vary considerably with species, tissue, substrate, energy demand and oxygen tension.
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Affiliation(s)
- Martin D Brand
- Buck Institute for Age Research, 8001 Redwood Blvd., Novato, CA 94945, USA.
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17
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Gorbacheva L, Davidova O, Sokolova E, Ishiwata S, Pinelis V, Strukova S, Reiser G. Endothelial protein C receptor is expressed in rat cortical and hippocampal neurons and is necessary for protective effect of activated protein C at glutamate excitotoxicity. J Neurochem 2009; 111:967-75. [PMID: 19780891 DOI: 10.1111/j.1471-4159.2009.06380.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Activated protein C (APC) is an anticoagulant and anti-inflammatory factor that acts via endothelial protein C receptor (EPCR). Interestingly, APC also exhibits neuroprotective activities. In the present study, we demonstrate for the first time expression of EPCR, the receptor for APC, in rat cortical and hippocampal neurons. Moreover, exposing the neurons to glutamate excitotoxicity we studied the functional consequence of the expression of EPCR. By cytotoxicity assay we showed that EPCR was necessary for the APC-mediated protective effect in both neuronal cell types in culture. The effect of APC was abrogated in the presence of blocking EPCR antibodies. Analysis of neuronal death by cell labelling with dyes which allow distinguishing living and dead cells confirmed that the anti-apoptotic effect of APC was dependent on both EPCR and protease-activated receptor-1. Thus, we suggest that binding of APC to EPCR on neurons and subsequent activation of protease-activated receptor-1 by the complex of APC-EPCR promotes survival mechanisms after exposure of neurons to damaging factors.
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Affiliation(s)
- Lyubov Gorbacheva
- Department of Human and Animal Physiology, Lomonosov Moscow State University, Moscow, Russia
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18
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Jekabsons MB. A systems biology approach to investigating apoptotic stimuli as effectors of cell metabolism: practical application of top-down control analysis to attached neurons. Int J Mol Sci 2009; 10:702-722. [PMID: 19333429 PMCID: PMC2660658 DOI: 10.3390/ijms10020702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Revised: 02/19/2009] [Accepted: 02/19/2009] [Indexed: 11/16/2022] Open
Abstract
Reduced glycolytic and mitochondrial respiration rates are common features of apoptosis that may reflect key events contributing to cell death. However, it is unclear to what extent the rate changes can be explained by direct alterations in the kinetics of the participating reactions, as changes in the concentrations of intermediates also affect reaction rates. Direct kinetic changes can be identified, ranked, and compared to the indirect effects mediated by the intermediates using top-down control analysis. Flux changes that are explained primarily by direct effects are likely to be prime targets of the pathways that signal death, and thus important contributors to apoptosis. Control analysis concepts relevant to identifying such effects are reviewed. Metabolic flux measurements are essential for this approach, but can be technically difficult, particularly when using adherent cells such as neurons. A simple method is described that renders such measurements feasible.
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Affiliation(s)
- Mika B Jekabsons
- Department of Biology, University of Mississippi / 110 Shoemaker Hall, University, MS 38677 USA
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Gleichmann M, Collis LP, Smith PJS, Mattson MP. Simultaneous single neuron recording of O2 consumption, [Ca2+]i and mitochondrial membrane potential in glutamate toxicity. J Neurochem 2009; 109:644-55. [PMID: 19226367 DOI: 10.1111/j.1471-4159.2009.05997.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In order to determine the sequence of cellular processes in glutamate toxicity, we simultaneously recorded O(2) consumption, cytosolic Ca(2+) concentration ([Ca(2+)](i)), and mitochondrial membrane potential (mDeltapsi) in single cortical neurons. Oxygen consumption was measured using an amperometric self-referencing platinum electrode adjacent to neurons in which [Ca(2+)](i) and mDeltapsi were monitored with Fluo-4 and TMRE(+), respectively, using a spinning disk laser confocal microscope. Excitotoxic doses of glutamate caused an elevation of [Ca(2+)](i) followed seconds afterwards by an increase in O(2) consumption which reached a maximum level within 1-5 min. A modest increase in mDeltapsi occurred during this time period, and then, shortly before maximal O(2) consumption was reached, the mDeltapsi, as indicated by TMRE(+) fluorescence, dissipated. Maximal O(2) consumption lasted up to 5 min and then declined together with mDeltapsi and ATP levels, while [Ca(2+)](i) further increased. mDeltapsi and [Ca(2+)](i) returned to baseline levels when neurons were treated with an NMDA receptor antagonist shortly after the [Ca(2+)](i) increased. Our unprecedented spatial and time resolution revealed that this sequence of events is identical in all neurons, albeit with considerable variability in magnitude and kinetics of changes in O(2) consumption, [Ca(2+)](i), and mDeltapsi. The data obtained using this new method are consistent with a model where Ca(2+) influx causes ATP depletion, despite maximal mitochondrial respiration, minutes after glutamate receptor activation.
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Affiliation(s)
- Marc Gleichmann
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Biomedical Research Center, Baltimore, Maryland, USA
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Jahani-Asl A, Cheung ECC, Neuspiel M, MacLaurin JG, Fortin A, Park DS, McBride HM, Slack RS. Mitofusin 2 Protects Cerebellar Granule Neurons against Injury-induced Cell Death. J Biol Chem 2007; 282:23788-98. [PMID: 17537722 DOI: 10.1074/jbc.m703812200] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Of the GTPases involved in the regulation of the fusion machinery, mitofusin 2 (Mfn2) plays an important role in the nervous system as point mutations of this isoform are associated with Charcot Marie Tooth neuropathy. Here, we investigate whether Mfn2 plays a role in the regulation of neuronal injury. We first examine mitochondrial dynamics following different modes of injury in cerebellar granule neurons. We demonstrate that neurons exposed to DNA damage or oxidative stress exhibit extensive mitochondrial fission, an early event preceding neuronal loss. The extent of mitochondrial fragmentation and remodeling is variable and depends on the mode and the severity of the death stimuli. Interestingly, whereas mitofusin 2 loss of function significantly induces cell death in the absence of any cell death stimuli, expression of mitofusin 2 prevents cell death following DNA damage, oxidative stress, and K+ deprivation induced apoptosis. More importantly, whereas wild-type Mfn2 and the hydrolysis-deficient mutant of Mfn2 (Mfn2(RasG12V)) function equally to promote fusion and lengthening of mitochondria, the activated Mfn2(RasG12V) mutant shows a significant increase in the protection of neurons against cell death and release of proapoptotic factor cytochrome c. These findings highlight a signaling role for Mfn2 in the regulation of apoptosis that extends beyond its role in mitochondrial fusion.
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Affiliation(s)
- Arezu Jahani-Asl
- Department of Cellular and Molecular Medicine, University of Ottawa, Neurosciences Program, Ottawa Health Research Institute, Ottawa, Ontario K1H 8M5, Canada
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Johnson-Cadwell LI, Jekabsons MB, Wang A, Polster BM, Nicholls DG. 'Mild Uncoupling' does not decrease mitochondrial superoxide levels in cultured cerebellar granule neurons but decreases spare respiratory capacity and increases toxicity to glutamate and oxidative stress. J Neurochem 2007; 101:1619-31. [PMID: 17437552 DOI: 10.1111/j.1471-4159.2007.04516.x] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cultured rat cerebellar granule neurons were incubated with low nanomolar concentrations of the protonophore carbonylcyanide-p-trifluoromethoxyphenyl hydrazone (FCCP) to test the hypothesis that 'mild uncoupling' could be neuroprotective by decreasing oxidative stress. To quantify the uncoupling, respiration and mitochondrial membrane potential (Deltapsi(m)) were determined in parallel as a function of FCCP concentration. Deltapsi(m) dropped by less than 10 mV before respiratory control was lost. Conditions for the valid estimation of matrix superoxide levels were determined from the rate of oxidation of the matrix-targeted fluorescent probe MitoSOX. No significant change in the level of matrix superoxide could be detected on addition of FCCP while respiratory control was retained, although cytoplasmic superoxide levels measured by dihydroethidium oxidation increased. 'Mild uncoupling' by 30 nmol/L FCCP did not alleviate neuronal dysregulation induced by glutathione depletion and significantly enhanced that due to menadione-induced oxidative stress. Low protonophore concentrations enhanced N-methyl-d-aspartate receptor-induced delayed calcium deregulation consistent with a decrease in the spare respiratory capacity available to match the bioenergetic demand of chronic receptor activation. It is concluded that the 'mild uncoupling' hypothesis is not supported by this model.
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Nicholls DG, Johnson-Cadwell L, Vesce S, Jekabsons M, Yadava N. Bioenergetics of mitochondria in cultured neurons and their role in glutamate excitotoxicity. J Neurosci Res 2007; 85:3206-12. [PMID: 17455297 DOI: 10.1002/jnr.21290] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The pathologic activation of NMDA receptors by glutamate is a major contributor to neuronal cell death after stroke. Receptor activation causes a massive influx of calcium into the neuron that is accumulated by the mitochondria. The favored hypothesis is that the calcium loaded mitochondria generate reactive oxygen species that damage and ultimately killed the neuron. In this review this hypothesis is critically re-examined with an emphasis on the role played by deficits in ATP generation. Novel techniques are developed to monitor the bioenergetic status of in situ mitochondria in cultured neurons. Applying these techniques to a model of glutamate excitotoxicity suggests that enhanced reactive oxygen species are a consequence rather than a cause of failed cytoplasmic calcium homeostasis (delayed calcium deregulation, [DCD]), but that prior oxidative damage facilitates DCD by damaging mitochondrial ATP generation. This impacts on current hypotheses relating to the neuroprotective effects of mild mitochondrial uncoupling.
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