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Borkar NA, Thompson MA, Bartman CM, Sathish V, Prakash YS, Pabelick CM. Nicotine affects mitochondrial structure and function in human airway smooth muscle cells. Am J Physiol Lung Cell Mol Physiol 2023; 325:L803-L818. [PMID: 37933473 PMCID: PMC11068407 DOI: 10.1152/ajplung.00158.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 09/26/2023] [Accepted: 10/24/2023] [Indexed: 11/08/2023] Open
Abstract
Exposure to cigarette smoke and e-cigarettes, with nicotine as the active constituent, contributes to increased health risks associated with asthma. Nicotine exerts its functional activity via nicotinic acetylcholine receptors (nAChRs), and the alpha7 subtype (α7nAChR) has recently been shown to adversely affect airway dynamics. The mechanisms of α7nAChR action in airways, particularly in the context of airway smooth muscle (ASM), a key cell type in asthma, are still under investigation. Mitochondria have garnered increasing interest for their role in regulating airway tone and adaptations to cellular stress. Here mitochondrial dynamics such as fusion versus fission, and mitochondrial Ca2+ ([Ca2+]m), play an important role in mitochondrial homeostasis. There is currently no information on effects and mechanisms by which nicotine regulates mitochondrial structure and function in ASM in the context of asthma. We hypothesized that nicotine disrupts mitochondrial morphology, fission-fusion balance, and [Ca2+]m regulation, with altered mitochondrial respiration and bioenergetics in the context of asthmatic ASM. Using human ASM (hASM) cells from nonasthmatics, asthmatics, and smokers, we examined the effects of nicotine on mitochondrial dynamics and [Ca2+]m. Fluorescence [Ca2+]m imaging of hASM cells with rhod-2 showed robust responses to 10 μM nicotine, particularly in asthmatics and smokers. In both asthmatics and smokers, nicotine increased the expression of fission proteins while decreasing fusion proteins. Seahorse analysis showed blunted oxidative phosphorylation parameters in response to nicotine in these groups. α7nAChR siRNA blunted nicotine effects, rescuing [Ca2+]m, changes in mitochondrial structural proteins, and mitochondrial dysfunction. These data highlight mitochondria as a target of nicotine effects on ASM, where mitochondrial disruption and impaired buffering could permit downstream effects of nicotine in the context of asthma.NEW & NOTEWORTHY Asthma is a major healthcare burden, which is further exacerbated by smoking. Recognizing the smoking risk of asthma, understanding the effects of nicotine on asthmatic airways becomes critical. Surprisingly, the mechanisms of nicotine action, even in normal and especially asthmatic airways, are understudied. Accordingly, the goal of this research is to investigate how nicotine influences asthmatic airways in terms of mitochondrial structure and function, via the a7nAChR.
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Affiliation(s)
- Niyati A Borkar
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - Michael A Thompson
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - Colleen M Bartman
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
| | - Venkatachalem Sathish
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, North Dakota, United States
| | - Y S Prakash
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
| | - Christina M Pabelick
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, United States
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States
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2
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Acharya TK, Kumar A, Kumar S, Goswami C. TRPV4 interacts with MFN2 and facilitates endoplasmic reticulum-mitochondrial contact points for Ca2+-buffering. Life Sci 2022; 310:121112. [DOI: 10.1016/j.lfs.2022.121112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 10/10/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022]
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3
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Song PP, Wang Y, Hou YP, Mao XW, Liu ZL, Wei M, Yu JP, Wang B, Qian YY, Yan L, Xu S, Jiang YQ, Zhou DQ, Yin M, Dou J. Crucial role of Ca 2+ /CN signalling pathway in the antifungal activity of disenecioyl-cis-khellactone against Botrytis cinerea. PEST MANAGEMENT SCIENCE 2022; 78:4649-4659. [PMID: 35866518 DOI: 10.1002/ps.7085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 06/21/2022] [Accepted: 07/22/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Botrytis cinerea causes grey mould and is one of the most destructive fungal pathogens affecting important fruit and vegetable crops. In preliminary studies, we found that disenecioyl-cis-khellactone (DK) had strong antifungal activity against several fungi species including B. cinerea [half maximal effective concentration (EC50 ) = 11.0 μg mL-1 ]. In this study, we aimed to further evaluate the antifungal activity of DK against B. cinerea and determine the role of calcium ion/calcineurin (Ca2+ /CN) signalling pathway on its antifungal effect. RESULTS DK was effective against B. cinerea in both in vitro and in vivo assays. Exogenous Ca2+ reduced the antifungal activity of DK. The combination of DK and cyclosporine A (CsA) did not exhibit an additive effect against B. cinerea. In contrast to CsA, DK reduced the intracellular Ca2+ concentration in B. cinerea. DK bound to calcineurin A (cnA) and up-regulated the expression of PMC1 and PMR1 genes. Moreover, DK sensitivity of △bccnA significantly decreased compared with that of Bc05.10 strain. CONCLUSION DK is a promising lead compound for developing fungicides against B. cinerea. The Ca2+ /CN signalling pathway plays a crucial role in the DK antifungal activity, and cnA is one of the targets of DK against B. cinerea. DK directly reacts with cnA, which up-regulates the transcription of Ca2+ /CN-dependent target genes PMC1 and PMR1, decreasing the intracellular Ca2+ concentration and disturbing the intracellular Ca2+ balance, leading to cell death. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Ping-Ping Song
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Nanjing, China
| | - Yu Wang
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Nanjing, China
| | - Yi-Ping Hou
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Xue-Wei Mao
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Zong-Liang Liu
- Yantai University, School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Centre of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai, China
| | - Min Wei
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Nanjing, China
| | - Jin-Ping Yu
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Nanjing, China
| | - Bi Wang
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Nanjing, China
| | - Yi-Yun Qian
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Nanjing, China
| | - Lu Yan
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Nanjing, China
| | - Shu Xu
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Nanjing, China
| | - Yan-Qin Jiang
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Nanjing, China
| | - Dong-Qin Zhou
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Nanjing, China
| | - Min Yin
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Nanjing, China
| | - Jian Dou
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Jiangsu Key Laboratory for the Research and Utilization of Plant Resources, Nanjing, China
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Yang M, He Y, Deng S, Xiao L, Tian M, Xin Y, Lu C, Zhao F, Gong Y. Mitochondrial Quality Control: A Pathophysiological Mechanism and Therapeutic Target for Stroke. Front Mol Neurosci 2022; 14:786099. [PMID: 35153669 PMCID: PMC8832032 DOI: 10.3389/fnmol.2021.786099] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 12/21/2021] [Indexed: 12/15/2022] Open
Abstract
Stroke is a devastating disease with high mortality and disability rates. Previous research has established that mitochondria, as major regulators, are both influenced by stroke, and further regulated the development of poststroke injury. Mitochondria are involved in several biological processes such as energy generation, calcium homeostasis, immune response, apoptosis regulation, and reactive oxygen species (ROS) generation. Meanwhile, mitochondria can evolve into various quality control systems, including mitochondrial dynamics (fission and fusion) and mitophagy, to maintain the homeostasis of the mitochondrial network. Various activities of mitochondrial fission and fusion are associated with mitochondrial integrity and neurological injury after stroke. Additionally, proper mitophagy seems to be neuroprotective for its effect on eliminating the damaged mitochondria, while excessive mitophagy disturbs energy generation and mitochondria-associated signal pathways. The balance between mitochondrial dynamics and mitophagy is more crucial than the absolute level of each process. A neurovascular unit (NVU) is a multidimensional system by which cells release multiple mediators and regulate diverse signaling pathways across the whole neurovascular network in a way with a high dynamic interaction. The turbulence of mitochondrial quality control (MQC) could lead to NVU dysfunctions, including neuron death, neuroglial activation, blood–brain barrier (BBB) disruption, and neuroinflammation. However, the exact changes and effects of MQC on the NVU after stroke have yet to be fully illustrated. In this review, we will discuss the updated mechanisms of MQC and the pathophysiology of mitochondrial dynamics and mitophagy after stroke. We highlight the regulation of MQC as a potential therapeutic target for both ischemic and hemorrhagic stroke.
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Affiliation(s)
- Miaoxian Yang
- Department of Critical Care Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Yu He
- Department of Critical Care Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Shuixiang Deng
- Department of Critical Care Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Lei Xiao
- The State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, The Institutes of Brain Science, Fudan University, Shanghai, China
| | - Mi Tian
- Department of Critical Care Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Yuewen Xin
- Department of Critical Care Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Chaocheng Lu
- Department of Critical Care Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Feng Zhao
- Department of Critical Care Medicine, Huashan Hospital, Fudan University, Shanghai, China
- *Correspondence: Feng Zhao,
| | - Ye Gong
- Department of Critical Care Medicine, Huashan Hospital, Fudan University, Shanghai, China
- Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China
- Ye Gong,
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5
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Lurette O, Guedouari H, Morris JL, Martín-Jiménez R, Robichaud JP, Hamel-Côté G, Khan M, Dauphinee N, Pichaud N, Prudent J, Hebert-Chatelain E. Mitochondrial matrix-localized Src kinase regulates mitochondrial morphology. Cell Mol Life Sci 2022; 79:327. [PMID: 35637383 PMCID: PMC9151517 DOI: 10.1007/s00018-022-04325-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 04/19/2022] [Accepted: 04/22/2022] [Indexed: 02/02/2023]
Abstract
The architecture of mitochondria adapts to physiological contexts: while mitochondrial fragmentation is usually associated to quality control and cell death, mitochondrial elongation often enhances cell survival during stress. Understanding how these events are regulated is important to elucidate how mitochondrial dynamics control cell fate. Here, we show that the tyrosine kinase Src regulates mitochondrial morphology. Deletion of Src increased mitochondrial size and reduced cellular respiration independently of mitochondrial mass, mitochondrial membrane potential or ATP levels. Re-expression of Src targeted to the mitochondrial matrix, but not of Src targeted to the plasma membrane, rescued mitochondrial morphology in a kinase activity-dependent manner. These findings highlight a novel function for Src in the control of mitochondrial dynamics.
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Affiliation(s)
- Olivier Lurette
- Canada Research Chair in Mitochondrial Signaling and Physiopathology, Moncton, NB Canada ,Department of Biology, University of Moncton, Moncton, NB Canada
| | - Hala Guedouari
- Canada Research Chair in Mitochondrial Signaling and Physiopathology, Moncton, NB Canada ,Department of Biology, University of Moncton, Moncton, NB Canada
| | - Jordan L. Morris
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XY UK
| | - Rebeca Martín-Jiménez
- Canada Research Chair in Mitochondrial Signaling and Physiopathology, Moncton, NB Canada ,Department of Biology, University of Moncton, Moncton, NB Canada
| | - Julie-Pier Robichaud
- Canada Research Chair in Mitochondrial Signaling and Physiopathology, Moncton, NB Canada ,Department of Biology, University of Moncton, Moncton, NB Canada
| | - Geneviève Hamel-Côté
- Canada Research Chair in Mitochondrial Signaling and Physiopathology, Moncton, NB Canada ,Department of Biology, University of Moncton, Moncton, NB Canada
| | - Mehtab Khan
- Canada Research Chair in Mitochondrial Signaling and Physiopathology, Moncton, NB Canada ,Department of Biology, University of Moncton, Moncton, NB Canada
| | - Nicholas Dauphinee
- Canada Research Chair in Mitochondrial Signaling and Physiopathology, Moncton, NB Canada ,Department of Biology, University of Moncton, Moncton, NB Canada
| | - Nicolas Pichaud
- Department of Chemistry and Biochemistry, University of Moncton, Moncton, NB Canada
| | - Julien Prudent
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XY UK
| | - Etienne Hebert-Chatelain
- Canada Research Chair in Mitochondrial Signaling and Physiopathology, Moncton, NB Canada ,Department of Biology, University of Moncton, Moncton, NB Canada
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6
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Shah SI, Paine JG, Perez C, Ullah G. Mitochondrial fragmentation and network architecture in degenerative diseases. PLoS One 2019; 14:e0223014. [PMID: 31557225 PMCID: PMC6762132 DOI: 10.1371/journal.pone.0223014] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 09/11/2019] [Indexed: 12/13/2022] Open
Abstract
Fragmentation of mitochondrial network has been implicated in many neurodegenerative, renal, and metabolic diseases. However, a quantitative measure of the microscopic parameters resulting in the impaired balance between fission and fusion of mitochondria and consequently the fragmented networks in a wide range of pathological conditions does not exist. Here we present a comprehensive analysis of mitochondrial networks in cells with Alzheimer's disease (AD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), optic neuropathy (OPA), diabetes/cancer, acute kidney injury, Ca2+ overload, and Down Syndrome (DS) pathologies that indicates significant network fragmentation in all these conditions. Furthermore, we found key differences in the way the microscopic rates of fission and fusion are affected in different conditions. The observed fragmentation in cells with AD, HD, DS, kidney injury, Ca2+ overload, and diabetes/cancer pathologies results from the imbalance between the fission and fusion through lateral interactions, whereas that in OPA, PD, and ALS results from impaired balance between fission and fusion arising from longitudinal interactions of mitochondria. Such microscopic difference leads to major disparities in the fine structure and topology of the network that could have significant implications for the way fragmentation affects various cell functions in different diseases.
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Affiliation(s)
- Syed I. Shah
- Department of Physics, University of South Florida, Tampa, FL, United States of America
| | - Johanna G. Paine
- Department of Physics, University of South Florida, Tampa, FL, United States of America
| | - Carlos Perez
- Department of Physics, University of South Florida, Tampa, FL, United States of America
| | - Ghanim Ullah
- Department of Physics, University of South Florida, Tampa, FL, United States of America
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7
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Developmental Axon Degeneration Requires TRPV1-Dependent Ca 2+ Influx. eNeuro 2019; 6:eN-NWR-0019-19. [PMID: 30838324 PMCID: PMC6399429 DOI: 10.1523/eneuro.0019-19.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 01/23/2019] [Accepted: 01/24/2019] [Indexed: 12/16/2022] Open
Abstract
Development of the nervous system relies on a balance between axon and dendrite growth and subsequent pruning and degeneration. The developmental degeneration of dorsal root ganglion (DRG) sensory axons has been well studied in part because it can be readily modeled by removing the trophic support by nerve growth factor (NGF) in vitro. We have recently reported that axonal fragmentation induced by NGF withdrawal is dependent on Ca2+, and here, we address the mechanism of Ca2+ entry required for developmental axon degeneration of mouse embryonic DRG neurons. Our results show that the transient receptor potential vanilloid family member 1 (TRPV1) cation channel plays a critical role mediating Ca2+ influx in DRG axons withdrawn from NGF. We further demonstrate that TRPV1 activation is dependent on reactive oxygen species (ROS) generation that is driven through protein kinase C (PKC) and NADPH oxidase (NOX)-dependent pathways that become active upon NGF withdrawal. These findings demonstrate novel mechanistic links between NGF deprivation, PKC activation, ROS generation, and TRPV1-dependent Ca2+ influx in sensory axon degeneration.
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8
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Mitochondrial uncoupler BAM15 inhibits artery constriction and potently activates AMPK in vascular smooth muscle cells. Acta Pharm Sin B 2018; 8:909-918. [PMID: 30505660 PMCID: PMC6251816 DOI: 10.1016/j.apsb.2018.07.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 07/08/2018] [Accepted: 07/19/2018] [Indexed: 12/15/2022] Open
Abstract
Our previous studies found that mitochondrial uncouplers CCCP and niclosamide inhibited artery constriction and the mechanism involved AMPK activation in vascular smooth muscle cells. BAM15 is a novel type of mitochondrial uncoupler. The aim of the present study is to identify the vasoactivity of BAM15 and characterize the BAM15-induced AMPK activation in vascular smooth muscle cells (A10 cells). BAM15 relaxed phenylephrine (PE)-induced constricted rat mesenteric arteries with intact and denuded endothelium. Pretreatment with BAM15 inhibited PE-induced constriction of rat mesenteric arteries with intact and denuded endothelium. BAM15, CCCP, and niclosamide had the comparable IC50 value of vasorelaxation in PE-induced constriction of rat mesenteric arteries. BAM15 was less cytotoxic in A10 cells compared with CCCP and niclosamide. BAM15 depolarized mitochondrial membrane potential, induced mitochondrial fission, increased mitochondrial ROS production, and increased mitochondrial oxygen consumption rate in A10 cells. BAM15 potently activated AMPK in A10 cells and the efficacy of BAM15 was stronger than that of CCCP, niclosamide, and AMPK positive activators metformin and AICAR. In conclusion, BAM15 activates AMPK in vascular smooth muscle cells with higher potency than that of CCCP, niclosamide and the known AMPK activators metformin and AICAR. The present work indicates that BAM15 is a potent AMPK activator.
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9
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Calcineurin Silencing in Dictyostelium discoideum Leads to Cellular Alterations Affecting Mitochondria, Gene Expression, and Oxidative Stress Response. Protist 2018; 169:584-602. [DOI: 10.1016/j.protis.2018.04.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 04/04/2018] [Accepted: 04/11/2018] [Indexed: 11/18/2022]
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10
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Nemani N, Carvalho E, Tomar D, Dong Z, Ketschek A, Breves SL, Jaña F, Worth AM, Heffler J, Palaniappan P, Tripathi A, Subbiah R, Riitano MF, Seelam A, Manfred T, Itoh K, Meng S, Sesaki H, Craigen WJ, Rajan S, Shanmughapriya S, Caplan J, Prosser BL, Gill DL, Stathopulos PB, Gallo G, Chan DC, Mishra P, Madesh M. MIRO-1 Determines Mitochondrial Shape Transition upon GPCR Activation and Ca 2+ Stress. Cell Rep 2018; 23:1005-1019. [PMID: 29694881 PMCID: PMC5973819 DOI: 10.1016/j.celrep.2018.03.098] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 02/22/2018] [Accepted: 03/21/2018] [Indexed: 01/08/2023] Open
Abstract
Mitochondria shape cytosolic calcium ([Ca2+]c) transients and utilize the mitochondrial Ca2+ ([Ca2+]m) in exchange for bioenergetics output. Conversely, dysregulated [Ca2+]c causes [Ca2+]m overload and induces permeability transition pore and cell death. Ablation of MCU-mediated Ca2+ uptake exhibited elevated [Ca2+]c and failed to prevent stress-induced cell death. The mechanisms for these effects remain elusive. Here, we report that mitochondria undergo a cytosolic Ca2+-induced shape change that is distinct from mitochondrial fission and swelling. [Ca2+]c elevation, but not MCU-mediated Ca2+ uptake, appears to be essential for the process we term mitochondrial shape transition (MiST). MiST is mediated by the mitochondrial protein Miro1 through its EF-hand domain 1 in multiple cell types. Moreover, Ca2+-dependent disruption of Miro1/KIF5B/tubulin complex is determined by Miro1 EF1 domain. Functionally, Miro1-dependent MiST is essential for autophagy/mitophagy that is attenuated in Miro1 EF1 mutants. Thus, Miro1 is a cytosolic Ca2+ sensor that decodes metazoan Ca2+ signals as MiST.
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Affiliation(s)
- Neeharika Nemani
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Edmund Carvalho
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Dhanendra Tomar
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Zhiwei Dong
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Andrea Ketschek
- Department of Anatomy and Cell Biology, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Sarah L Breves
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Fabián Jaña
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Alison M Worth
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Julie Heffler
- Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Palaniappan Palaniappan
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Aparna Tripathi
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Ramasamy Subbiah
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Massimo F Riitano
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Ajay Seelam
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Thomas Manfred
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Kie Itoh
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Shuxia Meng
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Hiromi Sesaki
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - William J Craigen
- Department of Molecular and Human Genetics, The Mitochondrial Diagnostic Laboratory, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sudarsan Rajan
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Santhanam Shanmughapriya
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Jeffrey Caplan
- Department of Biological Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA
| | - Benjamin L Prosser
- Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Donald L Gill
- Department of Cellular and Molecular Physiology, Penn State Hershey College of Medicine, Hershey, PA 17033, USA
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Western University, London, ON N6A 5C1, Canada
| | - Gianluca Gallo
- Department of Anatomy and Cell Biology, Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - David C Chan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Prashant Mishra
- Children's Medical Center Research Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Muniswamy Madesh
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA; Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA.
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11
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Adachi Y, Itoh K, Yamada T, Cerveny KL, Suzuki TL, Macdonald P, Frohman MA, Ramachandran R, Iijima M, Sesaki H. Coincident Phosphatidic Acid Interaction Restrains Drp1 in Mitochondrial Division. Mol Cell 2017; 63:1034-43. [PMID: 27635761 DOI: 10.1016/j.molcel.2016.08.013] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/20/2016] [Accepted: 08/09/2016] [Indexed: 12/31/2022]
Abstract
Mitochondria divide to control their size, distribution, turnover, and function. Dynamin-related protein 1 (Drp1) is a critical mechanochemical GTPase that drives constriction during mitochondrial division. It is generally believed that mitochondrial division is regulated during recruitment of Drp1 to mitochondria and its oligomerization into a division apparatus. Here, we report an unforeseen mechanism that regulates mitochondrial division by coincident interactions of Drp1 with the head group and acyl chains of phospholipids. Drp1 recognizes the head group of phosphatidic acid (PA) and two saturated acyl chains of another phospholipid by penetrating into the hydrophobic core of the membrane. The dual phospholipid interactions restrain Drp1 via inhibition of oligomerization-stimulated GTP hydrolysis that promotes membrane constriction. Moreover, a PA-producing phospholipase, MitoPLD, binds Drp1, creating a PA-rich microenvironment in the vicinity of a division apparatus. Thus, PA controls the activation of Drp1 after the formation of the division apparatus.
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Affiliation(s)
- Yoshihiro Adachi
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Kie Itoh
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Tatsuya Yamada
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Kara L Cerveny
- Department of Biology, Reed College, Portland, OR 97202, USA
| | - Takamichi L Suzuki
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Patrick Macdonald
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Michael A Frohman
- Department of Pharmacological Sciences and Center for Developmental Genetics, Stony Brook University, Stony Brook, NY 11794, USA
| | - Rajesh Ramachandran
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Miho Iijima
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA.
| | - Hiromi Sesaki
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA.
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12
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Spatiotemporal control of mitochondrial network dynamics in astroglial cells. Biochem Biophys Res Commun 2017; 500:17-25. [PMID: 28676398 DOI: 10.1016/j.bbrc.2017.06.191] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/30/2017] [Indexed: 12/17/2022]
Abstract
Mitochondria are increasingly recognized for playing important roles in regulating the evolving metabolic state of mammalian cells. This is particularly true for nerve cells, as dysregulation of mitochondrial dynamics is invariably associated with a number of neuropathies. Accumulating evidence now reveals that changes in mitochondrial dynamics and structure may play equally important roles also in the cell biology of astroglial cells. Astroglial cells display significant heterogeneity in their morphology and specialized functions across different brain regions, however besides fundamental differences they seem to share a surprisingly complex meshwork of mitochondria, which is highly suggestive of tightly regulated mechanisms that contribute to maintain this unique architecture. Here, we summarize recent work performed in astrocytes in situ indicating that this may indeed be the case, with astrocytic mitochondrial networks shown to experience rapid dynamic changes in response to defined external cues. Although the mechanisms underlying this degree of mitochondrial re-shaping are far from being understood, recent data suggest that they may contribute to demarcate astrocyte territories undergoing key signalling and metabolic functions.
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Lee DG, Park J, Lee HS, Lee SR, Lee DS. Iron overload-induced calcium signals modulate mitochondrial fragmentation in HT-22 hippocampal neuron cells. Toxicology 2016; 365:17-24. [PMID: 27481217 DOI: 10.1016/j.tox.2016.07.022] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 07/11/2016] [Accepted: 07/27/2016] [Indexed: 01/20/2023]
Abstract
Iron is necessary for neuronal functions; however, excessive iron accumulation caused by impairment of iron balance could damage neurons. Neuronal iron accumulation has been observed in several neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease. Nevertheless, the precise mechanisms underlying iron toxicity in neuron cells are not fully understood. In this study, we investigated the mechanism underlying iron overload-induced mitochondrial fragmentation in HT-22 hippocampal neuron cells that were incubated with ferric ammonium citrate (FAC). Mitochondrial fragmentation via dephosphorylation of Drp1 (Ser637) and increased apoptotic neuronal death were observed in FAC-stimulated HT-22 cells. Furthermore, the levels of intracellular calcium (Ca(2+)) were increased by iron overload. Notably, chelation of intracellular Ca(2+) rescued mitochondrial fragmentation and neuronal cell death. In addition, iron overload activated calcineurin through the Ca(2+)/calmodulin and Ca(2+)/calpain pathways. Pretreatment with the calmodulin inhibitor W13 and the calpain inhibitor ALLN attenuated iron overload-induced mitochondrial fragmentation and neuronal cell death. Therefore, these findings suggest that Ca(2+)-mediated calcineurin signals are a key player in iron-induced neurotoxicity by regulating mitochondrial dynamics. We believe that our results may contribute to the development of novel therapies for iron toxicity related neurodegenerative disorders.
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Affiliation(s)
- Dong Gil Lee
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Republic of Korea
| | - Junghyung Park
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Republic of Korea
| | - Hyun-Shik Lee
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Republic of Korea
| | - Sang-Rae Lee
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Chungcheonbuk-do, Republic of Korea
| | - Dong-Seok Lee
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Republic of Korea.
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14
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Joshi AU, Kornfeld OS, Mochly-Rosen D. The entangled ER-mitochondrial axis as a potential therapeutic strategy in neurodegeneration: A tangled duo unchained. Cell Calcium 2016; 60:218-34. [PMID: 27212603 DOI: 10.1016/j.ceca.2016.04.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 04/28/2016] [Accepted: 04/28/2016] [Indexed: 12/12/2022]
Abstract
Endoplasmic reticulum (ER) and mitochondrial function have both been shown to be critical events in neurodegenerative diseases. The ER mediates protein folding, maturation, sorting as well acts as calcium storage. The unfolded protein response (UPR) is a stress response of the ER that is activated by the accumulation of misfolded proteins within the ER lumen. Although the molecular mechanisms underlying ER stress-induced apoptosis are not completely understood, increasing evidence suggests that ER and mitochondria cooperate to signal cell death. Similarly, calcium-mediated mitochondrial function and dynamics not only contribute to ATP generation and calcium buffering but are also a linchpin in mediating cell fate. Mitochondria and ER form structural and functional networks (mitochondria-associated ER membranes [MAMs]) essential to maintaining cellular homeostasis and determining cell fate under various pathophysiological conditions. Regulated Ca(2+) transfer from the ER to the mitochondria is important in maintaining control of pro-survival/pro-death pathways. In this review, we summarize the latest therapeutic strategies that target these essential organelles in the context of neurodegenerative diseases.
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Affiliation(s)
- Amit U Joshi
- Department of Chemical & Systems Biology, School of Medicine, Stanford University, CA, USA
| | - Opher S Kornfeld
- Department of Chemical & Systems Biology, School of Medicine, Stanford University, CA, USA
| | - Daria Mochly-Rosen
- Department of Chemical & Systems Biology, School of Medicine, Stanford University, CA, USA.
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15
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Kif5 regulates mitochondrial movement, morphology, function and neuronal survival. Mol Cell Neurosci 2016; 72:22-33. [PMID: 26767417 DOI: 10.1016/j.mcn.2015.12.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 12/15/2015] [Accepted: 12/31/2015] [Indexed: 11/21/2022] Open
Abstract
Due to the unique architecture of neurons, trafficking of mitochondria throughout processes to regions of high energetic demand is critical to sustain neuronal health. It has been suggested that compromised mitochondrial trafficking may play a role in neurodegenerative diseases. We evaluated the consequences of disrupted kif5c-mediated mitochondrial trafficking on mitochondrial form and function in primary rat cortical neurons. Morphological changes in mitochondria appeared to be due to remodelling, a phenomenon distinct from mitochondrial fission, which resulted in punctate-shaped mitochondria. We also demonstrated that neurons displaying punctate mitochondria exhibited relatively decreased ROS and increased cellular ATP levels using ROS-sensitive GFP and ATP FRET probes, respectively. Somewhat unexpectedly, neurons overexpressing the dominant negative form of kif5c exhibited enhanced survival following excitotoxicity, suggesting that the impairment of mitochondrial trafficking conferred some form of neuroprotection. However, when neurons were exposed to H2O2, disruption of kif5c exacerbated cell death indicating that the effect on cell viability was dependent on the mode of toxicity. Our results suggest a novel role of kif5c. In addition to mediating mitochondrial transport, kif5c plays a role in the mechanism of regulating mitochondrial morphology. Our results also suggest that kif5c mediated mitochondrial dynamics may play an important role in regulating mitochondrial function and in turn cellular health. Moreover, our studies demonstrate an interesting interplay between the regulation of mitochondrial motility and morphology.
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16
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Ji WK, Hatch AL, Merrill RA, Strack S, Higgs HN. Actin filaments target the oligomeric maturation of the dynamin GTPase Drp1 to mitochondrial fission sites. eLife 2015; 4:e11553. [PMID: 26609810 PMCID: PMC4755738 DOI: 10.7554/elife.11553] [Citation(s) in RCA: 221] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 11/25/2015] [Indexed: 12/19/2022] Open
Abstract
While the dynamin GTPase Drp1 plays a critical role during mitochondrial fission, mechanisms controlling its recruitment to fission sites are unclear. A current assumption is that cytosolic Drp1 is recruited directly to fission sites immediately prior to fission. Using live-cell microscopy, we find evidence for a different model, progressive maturation of Drp1 oligomers on mitochondria through incorporation of smaller mitochondrially-bound Drp1 units. Maturation of a stable Drp1 oligomer does not forcibly lead to fission. Drp1 oligomers also translocate directionally along mitochondria. Ionomycin, a calcium ionophore, causes rapid mitochondrial accumulation of actin filaments followed by Drp1 accumulation at the fission site, and increases fission rate. Inhibiting actin polymerization, myosin IIA, or the formin INF2 reduces both un-stimulated and ionomycin-induced Drp1 accumulation and mitochondrial fission. Actin filaments bind purified Drp1 and increase GTPase activity in a manner that is synergistic with the mitochondrial protein Mff, suggesting a role for direct Drp1/actin interaction. We propose that Drp1 is in dynamic equilibrium on mitochondria in a fission-independent manner, and that fission factors such as actin filaments target productive oligomerization to fission sites. DOI:http://dx.doi.org/10.7554/eLife.11553.001 Inside cells, structures called mitochondria supply the energy needed to carry out the processes that sustain life. Mitochondria constantly divide (a process known as fission) or fuse together, which helps to keep them in good working condition and well distributed around the cell. Several neurological disorders, including Parkinson’s disease and Alzheimer’s, are associated with problems that affect mitochondrial fission. Many different molecules work together to help mitochondria divide, including a protein called Drp1. A number of Drp1 molecules can associate with each other to form an “oligomer” in the shape of a ring around a mitochondrion. The ring then constricts to split the mitochondrion in two. It is often assumed that Drp1 molecules are recruited to the mitochondria immediately before fission and then form the oligomer ring. However, by using microscopy to track the movement of fluorescently labeled Drp1 molecules in human cells, Ji, Hatch et al. now suggest that Drp1 is continuously binding to and releasing from mitochondria, regardless of the need for fission. The experiments showed that when bound to surface of the mitochondrion, Drp1 switches between assembling and disassembling the oligomer ring. This process of Drp1 assembly and oligomerization on mitochondria is called maturation. Specific signals for fission can push Drp1 toward maturation, which then leads to fission. Ji, Hatch et al. found that one such signal is the assembly of filaments of a protein called actin. Preventing actin filaments from forming reduced the amount of Drp1 that accumulated at mitochondria, and resulted in the mitochondria dividing less frequently. Further biochemical experiments also revealed that actin interacts directly with Drp1 and stimulates Drp1 activity, helping the ring to organize and assist mitochondrial fission. The formation of actin filaments is not the only mechanism that can recruit Drp1 to mitochondria. Future work should investigate whether other mechanisms work with actin to recruit Drp1. As with actin filaments, other signals might be predicted to influence the balance of maturation and disassembly of Drp1 oligomers. DOI:http://dx.doi.org/10.7554/eLife.11553.002
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Affiliation(s)
- Wei-ke Ji
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, United States
| | - Anna L Hatch
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, United States
| | - Ronald A Merrill
- Department of Pharmacology, The University of Iowa, Iowa City, United States
| | - Stefan Strack
- Department of Pharmacology, The University of Iowa, Iowa City, United States
| | - Henry N Higgs
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, United States
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Parameyong A, Govitrapong P, Chetsawang B. Melatonin attenuates the mitochondrial translocation of mitochondrial fission proteins and Bax, cytosolic calcium overload and cell death in methamphetamine-induced toxicity in neuroblastoma SH-SY5Y cells. Mitochondrion 2015; 24:1-8. [PMID: 26176977 DOI: 10.1016/j.mito.2015.07.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 06/09/2015] [Accepted: 07/09/2015] [Indexed: 12/22/2022]
Abstract
Methamphetamine (METH) is an addictive drug that can cause toxicity and degeneration in the brain. Several pieces of evidence have demonstrated that METH toxicity results in increases in oxidative stress that regulate an intracellular signaling cascade that leads to cell death. Recently, several studies have emphasized that the overload of cytosolic calcium levels and mitochondrial fission into a small mitochondrial structure is involved in cell death processes. In the present study, we aimed to investigate the effects of METH toxicity on cytosolic calcium overload and mitochondrial fission in neuroblastoma SH-SY5Y cells. Additionally, the protective effect of melatonin against METH-induced toxicity was also investigated. The results of the present study demonstrated that METH significantly decreases cell viability and increases the levels of mitochondrial fission (Fis1 and Drp1) proteins and pro-apoptotic protein, Bax in isolated mitochondria. The levels of Drp1 in the cytosol of METH-treated cells had no significant differences compared to the control untreated cells. METH also significantly increased the cytosolic calcium levels. Melatonin reversed the toxic effects of METH by restoring cell viability and inhibiting the increase in mitochondrial Fis1 levels and the mitochondrial translocation of Drp1 and Bax. Additionally, melatonin was able to reduce the METH-induced increase in cytosolic calcium levels and fragmented mitochondria into small globular structures in SH-SY5Y cells. The results of the present study demonstrate the potential abilities of melatonin to maintain the homeostasis of mitochondrial dynamics and cytosolic calcium levels in METH-induced toxicity in neuronal cells.
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Affiliation(s)
- Arisa Parameyong
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Salaya, Nakhon Pathom, Thailand
| | - Piyarat Govitrapong
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Salaya, Nakhon Pathom, Thailand; Center for Neuroscience and Department of Pharmacology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Banthit Chetsawang
- Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Salaya, Nakhon Pathom, Thailand.
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18
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Abstract
Astrocytes exhibit cellular excitability through variations in their intracellular calcium (Ca²⁺) levels in response to synaptic activity. Astrocyte Ca²⁺ elevations can trigger the release of neuroactive substances that can modulate synaptic transmission and plasticity, hence promoting bidirectional communication with neurons. Intracellular Ca²⁺ dynamics can be regulated by several proteins located in the plasma membrane, within the cytosol and by intracellular organelles such as mitochondria. Spatial dynamics and strategic positioning of mitochondria are important for matching local energy provision and Ca²⁺ buffering requirements to the demands of neuronal signalling. Although relatively unresolved in astrocytes, further understanding the role of mitochondria in astrocytes may reveal more about the complex bidirectional relationship between astrocytes and neurons in health and disease. In the present review, we discuss some recent insights regarding mitochondrial function, transport and turnover in astrocytes and highlight some important questions that remain to be answered.
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20
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Deheshi S, Dabiri B, Fan S, Tsang M, Rintoul GL. Changes in mitochondrial morphology induced by calcium or rotenone in primary astrocytes occur predominantly through ros-mediated remodeling. J Neurochem 2015; 133:684-99. [PMID: 25761412 DOI: 10.1111/jnc.13090] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 02/12/2015] [Accepted: 02/18/2015] [Indexed: 12/17/2022]
Abstract
Morphological changes in mitochondria have been primarily attributed to fission and fusion, while the more pliable transformations of mitochondria (remodeling, rounding, or stretching) have been largely overlooked. In this study, we quantify the contributions of fission and remodeling to changes in mitochondrial morphology induced by the Ca(2+) ionophore 4Br-A23187 and the metabolic toxin rotenone. We also examine the role of reactive oxygen species (ROS) in the regulation of mitochondrial remodeling. In agreement with our previous studies, mitochondrial remodeling, not fission, is the primary contributor to Ca(2+) -mediated changes in mitochondrial morphology induced by 4Br-A23187 in rat cortical astrocytes. Treatment with rotenone produced similar results. In both paradigms, remodeling was selectively blocked by antioxidants whereas fission was not, suggesting a ROS-mediated mechanism for mitochondrial remodeling. In support of this hypothesis, inhibition of endogenous ROS by overnight incubation in antioxidants resulted in elongated reticular networks of mitochondria. Examination of inner and outer mitochondrial membranes revealed that they largely acted in concert during the remodeling process. While mitochondrial morphology is traditionally ascribed to a net output of fission and fusion processes, in this study we provide evidence that the acute pliability of mitochondria can be a dominant factor in determining their morphology. More importantly, our results suggest that the remodeling process is independently regulated through a ROS-signaling mechanism. Mitochondrial morphology is traditionally ascribed to a balance of fission and fusion processes. We have shown that mitochondria can undergo more pliable transformations; remodeling, rounding, or stretching. We demonstrate that remodeling, not fission, is the primary contributor to calcium mediated changes in mitochondrial morphology in primary astrocytes. Others have shown fission is mediated by calcineurin. Our results suggest the remodeling process distinct from fission and is independently regulated through a ROS-signaling mechanism (CsA: Cyclosporine A; NAC: N-acetyl-l-cysteine; GSH: Reduced-L-Glutathione).
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Affiliation(s)
- Samineh Deheshi
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada
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21
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Alaimo A, Gorojod RM, Beauquis J, Muñoz MJ, Saravia F, Kotler ML. Deregulation of mitochondria-shaping proteins Opa-1 and Drp-1 in manganese-induced apoptosis. PLoS One 2014; 9:e91848. [PMID: 24632637 PMCID: PMC3954806 DOI: 10.1371/journal.pone.0091848] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 02/17/2014] [Indexed: 01/15/2023] Open
Abstract
Mitochondria are dynamic organelles that undergo fusion and fission processes. These events are regulated by mitochondria-shaping proteins. Changes in the expression and/or localization of these proteins lead to a mitochondrial dynamics impairment and may promote apoptosis. Increasing evidence correlates the mitochondrial dynamics disruption with the occurrence of neurodegenerative diseases. Therefore, we focused on this topic in Manganese (Mn)-induced Parkinsonism, a disorder associated with Mn accumulation preferentially in the basal ganglia where mitochondria from astrocytes represent an early target. Using MitoTracker Red staining we observed increased mitochondrial network fission in Mn-exposed rat astrocytoma C6 cells. Moreover, Mn induced a marked decrease in fusion protein Opa-1 levels as well as a dramatic increase in the expression of fission protein Drp-1. Additionally, Mn provoked a significant release of high MW Opa-1 isoforms from the mitochondria to the cytosol as well as an increased Drp-1 translocation to the mitochondria. Both Mdivi-1, a pharmacological Drp-1 inhibitor, and rat Drp-1 siRNA reduced the number of apoptotic nuclei, preserved the mitochondrial network integrity and prevented cell death. CsA, an MPTP opening inhibitor, prevented mitochondrial Δψm disruption, Opa-1 processing and Drp-1 translocation to the mitochondria therefore protecting Mn-exposed cells from mitochondrial disruption and apoptosis. The histological analysis and Hoechst 33258 staining of brain sections of Mn-injected rats in the striatum showed a decrease in cellular mass paralleled with an increase in the occurrence of apoptotic nuclei. Opa-1 and Drp-1 expression levels were also changed by Mn-treatment. Our results demonstrate for the first time that abnormal mitochondrial dynamics is implicated in both in vitro and in vivo Mn toxicity. In addition we show that the imbalance in fusion/fission equilibrium might be involved in Mn-induced apoptosis. This knowledge may provide new therapeutic tools for the treatment of Manganism and other neurodegenerative diseases.
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Affiliation(s)
- Agustina Alaimo
- Laboratorio de Apoptosis en el Sistema Nervioso y Nano-Oncología, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Química Biológica, Ciencias Exactas y Naturales (IQUIBICEN-CONICET), Buenos Aires, Argentina
| | - Roxana M. Gorojod
- Laboratorio de Apoptosis en el Sistema Nervioso y Nano-Oncología, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Química Biológica, Ciencias Exactas y Naturales (IQUIBICEN-CONICET), Buenos Aires, Argentina
| | - Juan Beauquis
- Laboratorio de Neurobiología, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina
| | - Manuel J. Muñoz
- Departamento de Fisiología, Biología Molecular y Celular and Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE-CONICET), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Flavia Saravia
- Laboratorio de Neurobiología, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina
| | - Mónica L. Kotler
- Laboratorio de Apoptosis en el Sistema Nervioso y Nano-Oncología, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and Instituto de Química Biológica, Ciencias Exactas y Naturales (IQUIBICEN-CONICET), Buenos Aires, Argentina
- * E-mail:
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Motility of astrocytic mitochondria is arrested by Ca2+-dependent interaction between mitochondria and actin filaments. Cell Calcium 2012. [PMID: 23177663 DOI: 10.1016/j.ceca.2012.10.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Motility of mitochondria, as well as their activity-dependent immobilization ("trapping"), is essential for neuronal function, but its regulation by cytoskeleton and relevance for glial cell signalling are unknown. Using time-lapse fluorescence imaging in rat cultured astrocytes, we evaluated the role of microtubules and actin filaments in motility of mitochondria in resting cells and during physiological or pathological Ca(2+) elevations. We found that mitochondria were significantly more aligned with microtubules than with actin filaments. Mitochondria were highly mobile under resting conditions at low intracellular free Ca(2+) concentrations ([Ca(2+)](i)). Activation of a moderate increase in [Ca(2+)](i) by either low-dose ionomycin or ATP immobilized mitochondria significantly but reversibly, without affecting mitochondrial morphology. A larger dose of ionomycin caused irreversible arrest and fragmentation of mitochondria. Disruption of microtubules completely arrested mitochondrial motility, while disruption of actin filaments had no effect on the basal mitochondrial motility at resting [Ca(2+)](i) levels but significantly reduced mitochondrial immobilization during [Ca(2+)](i) elevations. These results suggest that: (i) motility of astrocytic mitochondria is inversely related to [Ca(2+)](i), (ii) mitochondria require intact microtubules for their motility, and (iii) elevated [Ca(2+)](i) immobilizes mitochondria by strengthening their interaction with actin filaments.
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Ferree A, Shirihai O. Mitochondrial dynamics: the intersection of form and function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 748:13-40. [PMID: 22729853 DOI: 10.1007/978-1-4614-3573-0_2] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Mitochondria within a cell exist as a population in a dynamic -morphological continuum. The balance of mitochondrial fusion and fission dictates a spectrum of shapes from interconnected networks to fragmented individual units. This plasticity bestows the adaptive flexibility needed to adjust to changing cellular stresses and metabolic demands. The mechanisms that regulate mitochondrial dynamics, their importance in normal cell biology, and the roles they play in disease conditions are only beginning to be understood. Dysfunction of mitochondrial dynamics has been identified as a possible disease mechanism in Parkinson's disease. This chapter will introduce the budding field of mitochondrial dynamics and explore unique characteristics of affected neurons in Parkinson's disease that increase susceptibility to disruptions in mitochondrial dynamics.
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Affiliation(s)
- Andrew Ferree
- Department of Pharmacology, Boston University School of Medicine, Boston, MA, USA
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24
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High cytosolic free calcium level signals apoptosis through mitochondria-caspase mediated pathway in rat eggs cultured in vitro. Apoptosis 2012; 17:439-48. [PMID: 22311472 DOI: 10.1007/s10495-012-0702-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The present study was aimed to find out whether an increase of cytosolic free calcium level induces egg apoptosis through mitochondria-caspase mediated pathway. To increase cytosolic free calcium level and morphological apoptotic changes, ovulated eggs were cultured in Ca(2+)/Mg(2+) free media-199 with or without various concentrations of calcium ionophore (0.5, 1, 2, 3, 4 μM) for 3 h in vitro. The morphological apoptotic changes, cytosolic free calcium level, hydrogen peroxide (H(2)O(2)) concentration, catalase activity, cytochrome c concentration, caspase-9 and caspase-3 activities and DNA fragmentation were analyzed. Calcium ionophore induced morphological apoptotic features in a concentration-dependent manner followed by degeneration at higher concentrations (3 and 4 μM). Calcium ionophore increased cytosolic free calcium level, induced generation of hydrogen peroxide (H(2)O(2)) and inhibited catalase activity in treated eggs. The increased H(2)O(2) concentration was associated with increased cytochrome c concentration, caspase-9 and caspase-3 activities that resulted in the induction of morphological features characteristic of egg apoptosis. The increased caspase-3 activity finally induced DNA fragmentation as evidenced by TUNEL positive staining in calcium ionophore-treated eggs. These findings suggest that high cytosolic free calcium level induces generation of H(2)O(2) that leads to egg apoptosis through mitochondria-caspase mediated pathway.
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25
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Huang CCY, Ko ML, Vernikovskaya DI, Ko GYP. Calcineurin serves in the circadian output pathway to regulate the daily rhythm of L-type voltage-gated calcium channels in the retina. J Cell Biochem 2012; 113:911-22. [PMID: 22371971 DOI: 10.1002/jcb.23419] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The L-type voltage-gated calcium channels (L-VGCCs) in avian retinal cone photoreceptors are under circadian control, in which the protein expression of the α1 subunits and the current density are greater at night than during the day. Both Ras-mitogen-activated protein kinase (MAPK) and Ras-phosphatidylionositol 3 kinase-protein kinase B (PI3K-AKT) signaling pathways are part of the circadian output that regulate the L-VGCC rhythm, while cAMP-dependent signaling is further upstream of Ras to regulate the circadian outputs in photoreceptors. However, there are missing links between cAMP-dependent signaling and Ras in the circadian output regulation of L-VGCCs. In this study, we report that calcineurin, a Ca2+/calmodulin-dependent serine (ser)/threonine (thr) phosphatase, participates in the circadian output pathway to regulate L-VGCCs through modulating both Ras-MAPK and Ras-PI3K-AKT signaling. The activity of calcineurin, but not its protein expression, was under circadian regulation. Application of a calcineurin inhibitor, FK-506 or cyclosporine A, reduced the L-VGCC current density at night with a corresponding decrease in L-VGCCα1D protein expression, but the circadian rhythm of L-VGCCα1D mRNA levels were not affected. Inhibition of calcineurin further reduced the phosphorylation of ERK and AKT (at thr 308) and inhibited the activation of Ras, but inhibitors of MAPK or PI3K signaling did not affect the circadian rhythm of calcineurin activity. However, inhibition of adenylate cyclase significantly dampened the circadian rhythm of calcineurin activity. These results suggest that calcineurin is upstream of MAPK and PI3K-AKT but downstream of cAMP in the circadian regulation of L-VGCCs.
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Affiliation(s)
- Cathy Chia-Yu Huang
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas 77843-4458, USA
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Abstract
Structural changes and abnormal function of mitochondria have been documented in Down's syndrome (DS) cells, patients, and animal models. DS cells in culture exhibit a wide array of functional mitochondrial abnormalities including reduced mitochondrial membrane potential, reduced ATP production, and decreased oxido-reductase activity. New research has also brought to central stage the prominent role of oxidative stress in this condition. This review focuses on recent advances in the field with a particular emphasis on novel translational approaches involving the utilization of coenzyme Q(10) (CoQ(10) ) to treat a variety of clinical phenotypes associated with DS that are linked to increased oxidative stress and energy deficits. CoQ(10) has already provided promising results in several different conditions associated with altered energy metabolism and oxidative stress in the CNS. Two studies conducted in Ancona investigated the effect of CoQ(10) treatment on DNA damage in DS patients. Although the effect of CoQ(10) was evidenced only at single cell level, the treatment affected the distribution of cells according to their content in oxidized bases. In fact, it produced a strong negative correlation linking cellular CoQ(10) content and the amount of oxidized purines. Results suggest that the effect of CoQ(10) treatment in DS not only reflects antioxidant efficacy, but likely modulates DNA repair mechanisms.
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Affiliation(s)
- Luca Tiano
- Department of Biochemistry, Biology and Genetics, Polytechnic University of the Marche, Ancona, Italy.
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Effect of selenite on basic mitochondrial function in human osteosarcoma cells with chronic mitochondrial stress. Mitochondrion 2011; 12:149-55. [PMID: 21742063 DOI: 10.1016/j.mito.2011.06.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 06/20/2011] [Accepted: 06/24/2011] [Indexed: 11/22/2022]
Abstract
Mitochondrial chronic stress that originates from defective mitochondria is implicated in a growing list of human diseases. To enhance understanding of pathophysiology of chronic mitochondrial dysfunction we investigated human osteosarcoma cells with 2 types of chronic stress: corresponding to the mutation in ATP synthase subunit 6 encoded by mtDNA (NARP syndrome-mild stress) and to a total lack of mtDNA (Rho0 cells-heavy stress). We previously found that selenium influenced mitochondrial stress response and lowered ROS production. Therefore, in this study effect of selenite on other mitochondrial parameters was investigated. We showed that presence of selenium improved survival of starved cells, modified organization of mitochondrial network in NARP cybrids and decreased cytosolic calcium level in NARP and Rho0 cells. Selenium did not affect mitochondrial membrane potential, ATP level, activity of ATP synthase and activity of complex II of the respiratory chain.
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