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Development of Parvalbumin-Expressing Basket Terminals in Layer II of the Rat Medial Entorhinal Cortex. eNeuro 2018; 5:eN-NWR-0438-17. [PMID: 29951577 PMCID: PMC6019390 DOI: 10.1523/eneuro.0438-17.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 04/06/2018] [Accepted: 05/08/2018] [Indexed: 11/21/2022] Open
Abstract
Grid cells in layer II of the medial entorhinal cortex (MEC LII) generate multiple regular firing fields in response to the position and speed of an individual within the environment. They exhibit a protracted postnatal development and, in the adult, show activity differences along the dorsoventral axis (DVA). Evidence suggests parvalbumin-positive (PV+) interneurons, most of which are perisomatic-targeting cells, play a crucial role in generation of the hexagonal grid cell activity pattern. We therefore hypothesized that the development and organization of PV+ perisomatic terminals in MEC LII reflect the postnatal emergence of the hexagonal firing pattern and dorsoventral differences seen in grid cell activity. We used immuno-electron microscopy to examine the development of PV+ perisomatic terminals and their target somata within dorsal and ventral MEC LII in rats of postnatal day (P)10, P15, and P30. We demonstrate that in dorsal and ventral MEC LII, the cross-sectional area of somata and number and density of perisomatic PV+ terminals increase between P10 and P15. A simultaneous decrease was observed in cross-sectional area of PV+ terminals. Between P15 and P30, both MEC regions showed an increase in PV+ terminal size and percentage of PV+ terminals containing mitochondria, which may enable grid cell activity to emerge and stabilize. We also report that dorsal somata are larger and apposed by more PV+ terminals than ventral somata at all stages, suggesting a protracted maturation in the ventral portion and a possible gradient in soma size and PV+ basket innervation along the DVA in the adult.
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Davis SA, Itaman S, Khalid-Janney CM, Sherard JA, Dowell JA, Cairns NJ, Gitcho MA. TDP-43 interacts with mitochondrial proteins critical for mitophagy and mitochondrial dynamics. Neurosci Lett 2018; 678:8-15. [PMID: 29715546 DOI: 10.1016/j.neulet.2018.04.053] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 03/01/2018] [Accepted: 04/27/2018] [Indexed: 12/14/2022]
Abstract
Transactive response DNA-binding protein of 43 kDa (TDP-43) functions as a heterogeneous nuclear ribonucleoprotein and is the major pathological protein in frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis/motor neuron disease (ALS/MND). TDP-43 pathology may also be present as a comorbidity in approximately 20-50% of sporadic Alzheimer's disease cases. In a mouse model of MND, full-length TDP-43 increases association with the mitochondria and blocking the TDP-43/mitochondria interaction ameliorates motor dysfunction. Utilizing a proteomics screen, several mitochondrial TDP-43-interacting partners were identified, including voltage-gated anion channel 1 (VDAC1) and prohibitin 2 (PHB2), a crucial mitophagy receptor. Overexpression of TDP-43 led to an increase in PHB2 whereas TDP-43 knockdown reduced PHB2 expression in cells treated with carbonyl cyanide m-chlorophenylhydrazone (CCCP), an inducer of mitophagy. These results suggest that TDP-43 expression contributes to metabolism and mitochondrial function however we show no change in bioenergetics when TDP-43 is overexpressed and knocked down in HEK293T cells. Furthermore, the fusion protein mitofusin 2 (MFN2) interacts in complex with TDP-43 and selective expression of human TDP-43 in the hippocampus and cortex induced an age-dependent change in Mfn2 expression. Mitochondria morphology is altered in 9-month-old mice selectively expressing TDP-43 in an APP/PS1 background compared with APP/PS1 littermates. We further confirmed TDP-43 localization to the mitochondria using immunogold labeled TDP-43 transmission electron microscopy (TEM) and mitochondrial isolation methods There was no increase in full-length TDP-43 localized to the mitochondria in APP/PS1 mice compared to wild-type (littermates); however, using C- and N-terminal-specific TDP-43 antibodies, the N-terminal (27 kDa, N27) and C-terminal (30 kDa, C30) fragments of TDP-43 are greatly enriched in mitochondrial fractions. In addition, when the mitochondrial peptidase (PMPCA) is overexpressed there is an increase in the N-terminal fragment (N27). These results suggest that TDP-43 processing may contribute to metabolism and mitochondrial function.
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Affiliation(s)
- Stephani A Davis
- Department of Biological Sciences, Delaware State University, Dover, DE 19901, United States; Delaware Center for Neuroscience Research, Delaware State University, Dover, DE 19901, United States
| | - Sheed Itaman
- Department of Biological Sciences, Delaware State University, Dover, DE 19901, United States
| | | | - Justin A Sherard
- Department of Biological Sciences, Delaware State University, Dover, DE 19901, United States
| | - James A Dowell
- Wisconsin Institutes for Discovery, Madison, WI 53715, United States
| | - Nigel J Cairns
- Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, United States
| | - Michael A Gitcho
- Department of Biological Sciences, Delaware State University, Dover, DE 19901, United States; Delaware Center for Neuroscience Research, Delaware State University, Dover, DE 19901, United States.
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203
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Hung CHL, Cheng SSY, Cheung YT, Wuwongse S, Zhang NQ, Ho YS, Lee SMY, Chang RCC. A reciprocal relationship between reactive oxygen species and mitochondrial dynamics in neurodegeneration. Redox Biol 2018; 14:7-19. [PMID: 28837882 PMCID: PMC5567977 DOI: 10.1016/j.redox.2017.08.010] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 08/03/2017] [Accepted: 08/08/2017] [Indexed: 01/31/2023] Open
Abstract
Mitochondrial fragmentation due to fission/fusion imbalance has often been linked to mitochondrial dysfunction and apoptosis in neurodegeneration. Conventionally, it is believed that once mitochondrial morphology shifts away from its physiological tubular form, mitochondria become defective and downstream apoptotic signaling pathways are triggered. However, our study shows that beta-amyloid (Aβ) induces morphological changes in mitochondria where they become granular-shaped and are distinct from fragmented mitochondria in terms of both morphology and functions. Accumulation of mitochondrial reactive oxygen species triggers granular mitochondria formation, while mitoTEMPO (a mitochondria-targeted superoxide scavenger) restores tubular mitochondrial morphology within Aβ-treated neurons. Interestingly, modulations of mitochondria fission and fusion by genetic and pharmacological tools attenuated not only the induction of granular mitochondria, but also mitochondrial superoxide levels in Aβ-treated neurons. Our study shows a reciprocal relationship between mitochondrial dynamics and reactive oxygen species and provides a new potential therapeutic target at early stages of neurodegenerative disease pathogenesis.
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Affiliation(s)
- Clara Hiu-Ling Hung
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China; Institute of Chinese Medical Sciences, University of Macau, Macau, China
| | - Sally Shuk-Yee Cheng
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Yuen-Ting Cheung
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Suthicha Wuwongse
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Natalie Qishan Zhang
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Yuen-Shan Ho
- School of Nursing, Faculty of Health and Social Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | | | - Raymond Chuen-Chung Chang
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China; State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
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204
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205
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Wang W, Yin J, Ma X, Zhao F, Siedlak SL, Wang Z, Torres S, Fujioka H, Xu Y, Perry G, Zhu X. Inhibition of mitochondrial fragmentation protects against Alzheimer's disease in rodent model. Hum Mol Genet 2018; 26:4118-4131. [PMID: 28973308 DOI: 10.1093/hmg/ddx299] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 07/24/2017] [Indexed: 12/14/2022] Open
Abstract
Mitochondrial dysfunction is an early prominent feature in susceptible neurons in the brain of patients with Alzheimer's disease, which likely plays a critical role in the pathogenesis of disease. Increasing evidence suggests abnormal mitochondrial dynamics as important underlying mechanisms. In this study, we characterized marked mitochondrial fragmentation and abnormal mitochondrial distribution in the pyramidal neurons along with mitochondrial dysfunction in the brain of Alzheimer's disease mouse model CRND8 as early as 3 months of age before the accumulation of amyloid pathology. To establish the pathogenic significance of these abnormalities, we inhibited mitochondrial fragmentation by the treatment of mitochondrial division inhibitor 1 (mdivi-1), a mitochondrial fission inhibitor. Mdivi-1 treatment could rescue both mitochondrial fragmentation and distribution deficits and improve mitochondrial function in the CRND8 neurons both in vitro and in vivo. More importantly, the amelioration of mitochondrial dynamic deficits by mdivi-1 treatment markedly decreased extracellular amyloid deposition and Aβ1-42/Aβ1-40 ratio, prevented the development of cognitive deficits in Y-maze test and improved synaptic parameters. Our findings support the notion that abnormal mitochondrial dynamics plays an early and causal role in mitochondrial dysfunction and Alzheimer's disease-related pathological and cognitive impairments in vivo and indicate the potential value of restoration of mitochondrial dynamics as an innovative therapeutic strategy for Alzheimer's disease.
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Affiliation(s)
- Wenzhang Wang
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Jun Yin
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA.,Department of Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei 430071, China
| | - Xiaopin Ma
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Fanpeng Zhao
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Sandra L Siedlak
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Zhenlian Wang
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA.,School of Pharmaceutical Engineering & Life Sciences, Changzhou University, Changzhou, Jiansu 213164, China
| | - Sandy Torres
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Hisashi Fujioka
- Electron Microscopy Core Facility, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Ying Xu
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, State University of New York at Buffalo, Buffalo, NY 14222, USA
| | - George Perry
- Department of Biology, College of Science, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Xiongwei Zhu
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
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206
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Schmitt K, Grimm A, Dallmann R, Oettinghaus B, Restelli LM, Witzig M, Ishihara N, Mihara K, Ripperger JA, Albrecht U, Frank S, Brown SA, Eckert A. Circadian Control of DRP1 Activity Regulates Mitochondrial Dynamics and Bioenergetics. Cell Metab 2018; 27:657-666.e5. [PMID: 29478834 DOI: 10.1016/j.cmet.2018.01.011] [Citation(s) in RCA: 188] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 01/06/2017] [Accepted: 01/19/2018] [Indexed: 01/20/2023]
Abstract
Mitochondrial fission-fusion dynamics and mitochondrial bioenergetics, including oxidative phosphorylation and generation of ATP, are strongly clock controlled. Here we show that these circadian oscillations depend on circadian modification of dynamin-related protein 1 (DRP1), a key mediator of mitochondrial fission. We used a combination of in vitro and in vivo models, including human skin fibroblasts and DRP1-deficient or clock-deficient mice, to show that these dynamics are clock controlled via circadian regulation of DRP1. Genetic or pharmacological abrogation of DRP1 activity abolished circadian network dynamics and mitochondrial respiratory activity and eliminated circadian ATP production. Pharmacological silencing of pathways regulating circadian metabolism and mitochondrial function (e.g., sirtuins, AMPK) also altered DRP1 phosphorylation, and abrogation of DRP1 activity impaired circadian function. Our findings provide new insight into the crosstalk between the mitochondrial network and circadian cycles.
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Affiliation(s)
- Karen Schmitt
- Neurobiology Lab for Brain Aging and Mental Health, Transfaculty Research Platform, Molecular & Cognitive Neuroscience, University of Basel, Basel, Switzerland; Psychiatric University Clinics, University of Basel, Basel, Switzerland
| | - Amandine Grimm
- Neurobiology Lab for Brain Aging and Mental Health, Transfaculty Research Platform, Molecular & Cognitive Neuroscience, University of Basel, Basel, Switzerland; Psychiatric University Clinics, University of Basel, Basel, Switzerland
| | - Robert Dallmann
- Chronobiology and Sleep Research Group, Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Bjoern Oettinghaus
- Division of Neuropathology, Institute of Pathology, University Hospital Basel, Basel, Switzerland
| | - Lisa Michelle Restelli
- Division of Neuropathology, Institute of Pathology, University Hospital Basel, Basel, Switzerland
| | - Melissa Witzig
- Neurobiology Lab for Brain Aging and Mental Health, Transfaculty Research Platform, Molecular & Cognitive Neuroscience, University of Basel, Basel, Switzerland; Psychiatric University Clinics, University of Basel, Basel, Switzerland
| | - Naotada Ishihara
- Department of Protein Biochemistry, Institute of Life Science, Kurume University, Kurume 839-0864, Japan
| | - Katsuyoshi Mihara
- Department of Molecular Biology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Jürgen A Ripperger
- Department of Biology, Unit of Biochemistry, University of Fribourg, Fribourg, Switzerland
| | - Urs Albrecht
- Department of Biology, Unit of Biochemistry, University of Fribourg, Fribourg, Switzerland
| | - Stephan Frank
- Division of Neuropathology, Institute of Pathology, University Hospital Basel, Basel, Switzerland
| | - Steven A Brown
- Chronobiology and Sleep Research Group, Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.
| | - Anne Eckert
- Neurobiology Lab for Brain Aging and Mental Health, Transfaculty Research Platform, Molecular & Cognitive Neuroscience, University of Basel, Basel, Switzerland; Psychiatric University Clinics, University of Basel, Basel, Switzerland.
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207
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Wilson RJ, Drake JC, Cui D, Lewellen BM, Fisher CC, Zhang M, Kashatus DF, Palmer LA, Murphy MP, Yan Z. Mitochondrial protein S-nitrosation protects against ischemia reperfusion-induced denervation at neuromuscular junction in skeletal muscle. Free Radic Biol Med 2018; 117:180-190. [PMID: 29432799 PMCID: PMC5896769 DOI: 10.1016/j.freeradbiomed.2018.02.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 02/01/2018] [Accepted: 02/03/2018] [Indexed: 01/08/2023]
Abstract
Deterioration of neuromuscular junction (NMJ) integrity and function is causal to muscle atrophy and frailty, ultimately hindering quality of life and increasing the risk of death. In particular, NMJ is vulnerable to ischemia reperfusion (IR) injury when blood flow is restricted followed by restoration. However, little is known about the underlying mechanism(s) and hence the lack of effective interventions. New evidence suggests that mitochondrial oxidative stress plays a causal role in IR injury, which can be precluded by enhancing mitochondrial protein S-nitrosation (SNO). To elucidate the role of IR and mitochondrial protein SNO in skeletal muscle, we utilized a clinically relevant model and showed that IR resulted in significant muscle and motor nerve injuries with evidence of elevated muscle creatine kinase in the serum, denervation at NMJ, myofiber degeneration and regeneration, as well as muscle atrophy. Interestingly, we observed that neuromuscular transmission improved prior to muscle recovery, suggesting the importance of the motor nerve in muscle functional recovery. Injection of a mitochondria-targeted S-nitrosation enhancing agent, MitoSNO, into ischemic muscle prior to reperfusion reduced mitochondrial oxidative stress in the motor nerve and NMJ, attenuated denervation at NMJ, and resulted in accelerated functional recovery of the muscle. These findings demonstrate that enhancing mitochondrial protein SNO protects against IR-induced denervation at NMJ in skeletal muscle and accelerates functional regeneration. This could be an efficacious intervention for protecting neuromuscular injury under the condition of IR and other related pathological conditions.
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Affiliation(s)
- Rebecca J Wilson
- Departments of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Joshua C Drake
- Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Di Cui
- Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Bevan M Lewellen
- Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Carleigh C Fisher
- Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Mei Zhang
- Departments of Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - David F Kashatus
- Departments of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Lisa A Palmer
- Departments of Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Michael P Murphy
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Zhen Yan
- Departments of Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Departments of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Departments of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
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208
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Abstract
Alzheimer's disease (AD) is characterized by brain deposition of amyloid plaques and tau neurofibrillary tangles along with steady cognitive decline. Synaptic damage, an early pathological event, correlates strongly with cognitive deficits and memory loss. Mitochondria are essential organelles for synaptic function. Neurons utilize specialized mechanisms to drive mitochondrial trafficking to synapses in which mitochondria buffer Ca2+ and serve as local energy sources by supplying ATP to sustain neurotransmitter release. Mitochondrial abnormalities are one of the earliest and prominent features in AD patient brains. Amyloid-β (Aβ) and tau both trigger mitochondrial alterations. Accumulating evidence suggests that mitochondrial perturbation acts as a key factor that is involved in synaptic failure and degeneration in AD. The importance of mitochondria in supporting synaptic function has made them a promising target of new therapeutic strategies for AD. Here, we review the molecular mechanisms regulating mitochondrial function at synapses, highlight recent findings on the disturbance of mitochondrial dynamics and transport in AD, and discuss how these alterations impact synaptic vesicle release and thus contribute to synaptic pathology associated with AD.
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209
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Martins IV, Rivers-Auty J, Allan SM, Lawrence CB. Mitochondrial Abnormalities and Synaptic Loss Underlie Memory Deficits Seen in Mouse Models of Obesity and Alzheimer's Disease. J Alzheimers Dis 2018; 55:915-932. [PMID: 27802235 PMCID: PMC5278950 DOI: 10.3233/jad-160640] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Obesity is associated with impaired memory in humans, and obesity induced by high-fat diets leads to cognitive deficits in rodents and in mouse models of Alzheimer's disease (AD). However, it remains unclear how high-fat diets contribute to memory impairment. Therefore, we tested the effect of a high-fat diet on memory in male and female control non-transgenic (Non-Tg) and triple-transgenic AD (3xTgAD) mice and determined if a high-fat diet caused similar ultrastructural abnormalities to those observed in AD. Behavior was assessed in mice on control or high-fat diet at 4, 8, or 14 months of age and ultrastructural analysis at 8 months of age. A high-fat diet increased body weight, fat weight, and insulin levels with some differences in these metabolic responses observed between Non-Tg and 3xTgAD mice. In both sexes, high-fat feeding caused memory impairments in Non-Tg mice and accelerated memory deficits in 3xTgAD mice. In 3xTgAD mice, changes in hippocampal mitochondrial morphology were observed in capillaries and brain neuropil that were accompanied by a reduction in synapse number. A high-fat diet also caused mitochondria abnormalities and a reduction in synapse number in Non-Tg mice, but did not exacerbate the changes seen in 3xTgAD mice. Our data demonstrate that a high-fat diet affected memory in Non-Tg mice and produced similar impairments in mitochondrial morphology and synapse number comparable to those seen in AD mice, suggesting that the detrimental effects of a high-fat diet on memory might be due to changes in mitochondrial morphology leading to a reduction in synaptic number.
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Affiliation(s)
| | | | | | - Catherine B. Lawrence
- Correspondence to: Catherine B. Lawrence, PhD, Faculty of Life Sciences, A.V. Hill Building, University of Manchester, Oxford Road, Manchester, M13 9PT, UK. Tel.: +44 161 275 5253; E-mail:
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210
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Unraveling Synaptic GCaMP Signals: Differential Excitability and Clearance Mechanisms Underlying Distinct Ca 2+ Dynamics in Tonic and Phasic Excitatory, and Aminergic Modulatory Motor Terminals in Drosophila. eNeuro 2018; 5:eN-NWR-0362-17. [PMID: 29464198 PMCID: PMC5818553 DOI: 10.1523/eneuro.0362-17.2018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 01/27/2018] [Accepted: 02/02/2018] [Indexed: 11/21/2022] Open
Abstract
GCaMP is an optogenetic Ca2+ sensor widely used for monitoring neuronal activities but the precise physiological implications of GCaMP signals remain to be further delineated among functionally distinct synapses. The Drosophila neuromuscular junction (NMJ), a powerful genetic system for studying synaptic function and plasticity, consists of tonic and phasic glutamatergic and modulatory aminergic motor terminals of distinct properties. We report a first simultaneous imaging and electric recording study to directly contrast the frequency characteristics of GCaMP signals of the three synapses for physiological implications. Different GCaMP variants were applied in genetic and pharmacological perturbation experiments to examine the Ca2+ influx and clearance processes underlying the GCaMP signal. Distinct mutational and drug effects on GCaMP signals indicate differential roles of Na+ and K+ channels, encoded by genes including paralytic (para), Shaker (Sh), Shab, and ether-a-go-go (eag), in excitability control of different motor terminals. Moreover, the Ca2+ handling properties reflected by the characteristic frequency dependence of the synaptic GCaMP signals were determined to a large extent by differential capacity of mitochondria-powered Ca2+ clearance mechanisms. Simultaneous focal recordings of synaptic activities further revealed that GCaMPs were ineffective in tracking the rapid dynamics of Ca2+ influx that triggers transmitter release, especially during low-frequency activities, but more adequately reflected cytosolic residual Ca2+ accumulation, a major factor governing activity-dependent synaptic plasticity. These results highlight the vast range of GCaMP response patterns in functionally distinct synaptic types and provide relevant information for establishing basic guidelines for the physiological interpretations of presynaptic GCaMP signals from in situ imaging studies.
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211
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Koch RE, Hill GE. Behavioural mating displays depend on mitochondrial function: a potential mechanism for linking behaviour to individual condition. Biol Rev Camb Philos Soc 2018; 93:1387-1398. [DOI: 10.1111/brv.12400] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 01/15/2018] [Accepted: 01/19/2018] [Indexed: 12/22/2022]
Affiliation(s)
- Rebecca E. Koch
- Department of Biological Sciences; Auburn University; Auburn AL 36849 U.S.A
| | - Geoffrey E. Hill
- Department of Biological Sciences; Auburn University; Auburn AL 36849 U.S.A
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212
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Understanding Miro GTPases: Implications in the Treatment of Neurodegenerative Disorders. Mol Neurobiol 2018; 55:7352-7365. [PMID: 29411264 PMCID: PMC6096957 DOI: 10.1007/s12035-018-0927-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 01/24/2018] [Indexed: 12/19/2022]
Abstract
The Miro GTPases represent an unusual subgroup of the Ras superfamily and have recently emerged as important mediators of mitochondrial dynamics and for maintaining neuronal health. It is now well-established that these enzymes act as essential components of a Ca2+-sensitive motor complex, facilitating the transport of mitochondria along microtubules in several cell types, including dopaminergic neurons. The Miros appear to be critical for both anterograde and retrograde mitochondrial transport in axons and dendrites, both of which are considered essential for neuronal health. Furthermore, the Miros may be significantly involved in the development of several serious pathological processes, including the development of neurodegenerative and psychiatric disorders. In this review, we discuss the molecular structure and known mitochondrial functions of the Miro GTPases in humans and other organisms, in the context of neurodegenerative disease. Finally, we consider the potential human Miros hold as novel therapeutic targets for the treatment of such disease.
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213
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Mitochondrial Ultrastructure Is Coupled to Synaptic Performance at Axonal Release Sites. eNeuro 2018; 5:eN-NWR-0390-17. [PMID: 29383328 PMCID: PMC5788698 DOI: 10.1523/eneuro.0390-17.2018] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 12/28/2017] [Accepted: 01/06/2018] [Indexed: 01/08/2023] Open
Abstract
Mitochondrial function in neurons is tightly linked with metabolic and signaling mechanisms that ultimately determine neuronal performance. The subcellular distribution of these organelles is dynamically regulated as they are directed to axonal release sites on demand, but whether mitochondrial internal ultrastructure and molecular properties would reflect the actual performance requirements in a synapse-specific manner, remains to be established. Here, we examined performance-determining ultrastructural features of presynaptic mitochondria in GABAergic and glutamatergic axons of mice and human. Using electron-tomography and super-resolution microscopy we found, that these features were coupled to synaptic strength: mitochondria in boutons with high synaptic activity exhibited an ultrastructure optimized for high rate metabolism and contained higher levels of the respiratory chain protein cytochrome-c (CytC) than mitochondria in boutons with lower activity. The strong, cell type-independent correlation between mitochondrial ultrastructure, molecular fingerprints and synaptic performance suggests that changes in synaptic activity could trigger ultrastructural plasticity of presynaptic mitochondria, likely to adjust their performance to the actual metabolic demand.
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214
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Higuchi-Sanabria R, Frankino PA, Paul JW, Tronnes SU, Dillin A. A Futile Battle? Protein Quality Control and the Stress of Aging. Dev Cell 2018; 44:139-163. [PMID: 29401418 PMCID: PMC5896312 DOI: 10.1016/j.devcel.2017.12.020] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 11/30/2017] [Accepted: 12/20/2017] [Indexed: 12/15/2022]
Abstract
There exists a phenomenon in aging research whereby early life stress can have positive impacts on longevity. The mechanisms underlying these observations suggest a robust, long-lasting induction of cellular defense mechanisms. These include the various unfolded protein responses of the endoplasmic reticulum (ER), cytosol, and mitochondria. Indeed, ectopic induction of these pathways, in the absence of stress, is sufficient to increase lifespan in organisms as diverse as yeast, worms, and flies. Here, we provide an overview of the protein quality control mechanisms that operate in the cytosol, mitochondria, and ER and discuss how they affect cellular health and viability during stress and aging.
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Affiliation(s)
- Ryo Higuchi-Sanabria
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Phillip Andrew Frankino
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Joseph West Paul
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Sarah Uhlein Tronnes
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Andrew Dillin
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA; The Glenn Center for Aging Research, University of California, Berkeley, Berkeley, CA 94720, USA.
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215
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Pesaresi M, Giatti S, Spezzano R, Romano S, Diviccaro S, Borsello T, Mitro N, Caruso D, Garcia-Segura LM, Melcangi RC. Axonal transport in a peripheral diabetic neuropathy model: sex-dimorphic features. Biol Sex Differ 2018; 9:6. [PMID: 29351809 PMCID: PMC5775621 DOI: 10.1186/s13293-018-0164-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 01/02/2018] [Indexed: 02/07/2023] Open
Abstract
Background Disruption of axonal transport plays a pivotal role in diabetic neuropathy. A sex-dimorphism exists in the incidence and symptomatology of diabetic neuropathy; however, no studies so far have addressed sex differences in axonal motor proteins expression in early diabetes as well as the possible involvement of neuroactive steroids. Interestingly, recent data point to a role for mitochondria in the sexual dimorphism of neurodegenerative diseases. Mitochondria have a fundamental role in axonal transport by producing the motors’ energy source, ATP. Moreover, neuroactive steroids can also regulate mitochondrial function. Methods Here, we investigated the impact of short-term diabetes in the peripheral nervous system of male and female rats on key motor proteins important for axonal transport, mitochondrial function, and neuroactive steroids levels. Results We show that short-term diabetes alters mRNA levels and axoplasm protein contents of kinesin family member KIF1A, KIF5B, KIF5A and Myosin Va in male but not in female rats. Similarly, the expression of peroxisome proliferator-activated receptor γ co-activator-1α, a subunit of the respiratory chain complex IV, ATP levels and the key regulators of mitochondrial dynamics were affected in males but not in females. Concomitant analysis of neuroactive steroid levels in sciatic nerve showed an alteration of testosterone, dihydrotestosterone, and allopregnanolone in diabetic males, whereas no changes were observed in female rats. Conclusions These findings suggest that sex-specific decrease in neuroactive steroid levels in male diabetic animals may cause an alteration in their mitochondrial function that in turn might impact in axonal transport, contributing to the sex difference observed in diabetic neuropathy.
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Affiliation(s)
- Marzia Pesaresi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Silvia Giatti
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Roberto Spezzano
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Simone Romano
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Silvia Diviccaro
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Tiziana Borsello
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy.,Department of Neuroscience, IRCCS-Mario Negri Institute for Pharmacological Research, Milano, Italy
| | - Nico Mitro
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Donatella Caruso
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy
| | - Luis Miguel Garcia-Segura
- Instituto Cajal, CSIC, CIBER de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
| | - Roberto Cosimo Melcangi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy.
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216
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Compound heterozygous SPATA5 variants in four families and functional studies of SPATA5 deficiency. Eur J Hum Genet 2018; 26:407-419. [PMID: 29343804 PMCID: PMC5838984 DOI: 10.1038/s41431-017-0001-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 07/17/2017] [Accepted: 08/23/2017] [Indexed: 12/16/2022] Open
Abstract
Variants in the SPATA5 gene were recently described in a cohort of patients with global developmental delay, sensorineural hearing loss, seizures, cortical visual impairment and microcephaly. SPATA5 protein localizes predominantly in the mitochondria and is proposed to be involved in mitochondrial function and brain developmental processes. However no functional studies have been performed. This study describes five patients with psychomotor developmental delay, microcephaly, epilepsy and hearing impairment, who were thought clinically to have a mitochondrial disease with subsequent whole-exome sequencing analysis detecting compound heterozygous variants in the SPATA5 gene. A summary of clinical data of all the SPATA5 patients reported in the literature confirms the characteristic phenotype. To assess SPATA5’s role in mitochondrial dynamics, functional studies were performed on rat cortical neurons. SPATA5-deficient neurons had a significant imbalance in the mitochondrial fusion-fission rate, impaired energy production and short axons. In conclusion, SPATA5 protein has an important role in mitochondrial dynamics and axonal growth. Biallelic variants in the SPATA5 gene can affect mitochondria in cortical neurons and should be considered in patients with a neurodegenerative disorder and/or with clinical presentation resembling a mitochondrial disorder.
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217
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Rzepnikowska W, Kochański A. A role for the GDAP1 gene in the molecular pathogenesis of Charcot-Marie-Tooth disease. Acta Neurobiol Exp (Wars) 2018. [DOI: 10.21307/ane-2018-002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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218
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Yan SF, Akhter F, Sosunov AA, Yan SS. Identification and Characterization of Amyloid-β Accumulation in Synaptic Mitochondria. Methods Mol Biol 2018; 1779:415-433. [PMID: 29886547 DOI: 10.1007/978-1-4939-7816-8_25] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Mitochondrial and synaptic dysfunction is an early pathological feature of Alzheimer's disease (AD). Accumulation of amyloid beta-peptide (Aβ) in mitochondria, particularly in synaptic mitochondria, potentiates and amplifies synaptic injury and disruption of synaptic transmission, leading to synaptic dysfunction and ultimately to synaptic failure. Thus, determination of the presence and levels of Aβ in synaptic mitochondria associated with amyloid pathology is important for studying mitochondrial amyloid pathology. Here, we present a detailed methodology for the isolation of synaptic mitochondria from brain tissues and the determination of Aβ levels in the isolated mitochondria as well as ultrastructural localization of synaptic mitochondrial Aβ. These methods have been used successfully for the identification and characterization of Aβ accumulation in synaptic mitochondria from mouse brains derived from transgenic AD mouse model. Additionally, we comprehensively discuss the sample preparation, experimental details, our unique procedures, optimization of parameters, and troubleshooting.
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Affiliation(s)
- Shi Fang Yan
- Department of Pharmacology and Toxicology, Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS, USA.
| | - Firoz Akhter
- Department of Pharmacology and Toxicology, Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS, USA
| | | | - Shirley ShiDu Yan
- Department of Pharmacology and Toxicology, Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS, USA.
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219
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Yamaguchi M, Takashima H. Drosophila Charcot-Marie-Tooth Disease Models. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1076:97-117. [PMID: 29951817 DOI: 10.1007/978-981-13-0529-0_7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Charcot-Marie-Tooth disease (CMT) was initially described in 1886. It is characterized by defects in the peripheral nervous system, including sensory and motor neurons. Although more than 80 CMT-causing genes have been identified to date, an effective therapy has not yet been developed for this disease. Since Drosophila does not have axons surrounded by myelin sheaths or Schwann cells, the establishment of a demyelinating CMT model is not appropriate. In this chapter, after overviewing CMT, examples of Drosophila CMT models with axonal neuropathy and other animal CMT models are described.
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Affiliation(s)
| | - Hiroshi Takashima
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
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220
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Ordonez DG, Lee MK, Feany MB. α-synuclein Induces Mitochondrial Dysfunction through Spectrin and the Actin Cytoskeleton. Neuron 2017; 97:108-124.e6. [PMID: 29249285 DOI: 10.1016/j.neuron.2017.11.036] [Citation(s) in RCA: 165] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 10/18/2017] [Accepted: 11/21/2017] [Indexed: 01/20/2023]
Abstract
Genetics and neuropathology strongly link α-synuclein aggregation and neurotoxicity to the pathogenesis of Parkinson's disease and related α-synucleinopathies. Here we describe a new Drosophila model of α-synucleinopathy based on widespread expression of wild-type human α-synuclein, which shows robust neurodegeneration, early-onset locomotor deficits, and abundant α-synuclein aggregation. We use results of forward genetic screening and genetic analysis in our new model to demonstrate that α-synuclein expression promotes reorganization of the actin filament network and consequent mitochondrial dysfunction through altered Drp1 localization. Similar changes are present in a mouse α-synucleinopathy model and in postmortem brain tissue from patients with α-synucleinopathy. Importantly, we provide evidence that the interaction of α-synuclein with spectrin initiates pathological alteration of the actin cytoskeleton and downstream neurotoxicity. These findings suggest new therapeutic approaches for α-synuclein induced neurodegeneration.
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Affiliation(s)
- Dalila G Ordonez
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Michael K Lee
- Department of Neuroscience, Institute of Translational Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Mel B Feany
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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221
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Chuang CS, Chang JC, Cheng FC, Liu KH, Su HL, Liu CS. Modulation of mitochondrial dynamics by treadmill training to improve gait and mitochondrial deficiency in a rat model of Parkinson's disease. Life Sci 2017; 191:236-244. [DOI: 10.1016/j.lfs.2017.10.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 09/25/2017] [Accepted: 10/02/2017] [Indexed: 11/16/2022]
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222
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Ebrahimi-Fakhari D, Saffari A, Wahlster L, Di Nardo A, Turner D, Lewis TL, Conrad C, Rothberg JM, Lipton JO, Kölker S, Hoffmann GF, Han MJ, Polleux F, Sahin M. Impaired Mitochondrial Dynamics and Mitophagy in Neuronal Models of Tuberous Sclerosis Complex. Cell Rep 2017; 17:1053-1070. [PMID: 27760312 DOI: 10.1016/j.celrep.2016.09.054] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 07/11/2016] [Accepted: 09/15/2016] [Indexed: 01/08/2023] Open
Abstract
Tuberous sclerosis complex (TSC) is a neurodevelopmental disease caused by TSC1 or TSC2 mutations and subsequent activation of the mTORC1 kinase. Upon mTORC1 activation, anabolic metabolism, which requires mitochondria, is induced, yet at the same time the principal pathway for mitochondrial turnover, autophagy, is compromised. How mTORC1 activation impacts mitochondrial turnover in neurons remains unknown. Here, we demonstrate impaired mitochondrial homeostasis in neuronal in vitro and in vivo models of TSC. We find that Tsc1/2-deficient neurons accumulate mitochondria in cell bodies, but are depleted of axonal mitochondria, including those supporting presynaptic sites. Axonal and global mitophagy of damaged mitochondria is impaired, suggesting that decreased turnover may act upstream of impaired mitochondrial metabolism. Importantly, blocking mTORC1 or inducing mTOR-independent autophagy restores mitochondrial homeostasis. Our study clarifies the complex relationship between the TSC-mTORC1 pathway, autophagy, and mitophagy, and defines mitochondrial homeostasis as a therapeutic target for TSC and related diseases.
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Affiliation(s)
- Darius Ebrahimi-Fakhari
- The F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Afshin Saffari
- The F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Lara Wahlster
- Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany; Division of Hematology and Oncology, Stem Cell Program, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Alessia Di Nardo
- The F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Daria Turner
- The F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Tommy L Lewis
- Department of Neuroscience, Zuckerman Mind Brain Behavior Institute and Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | | | | | - Jonathan O Lipton
- The F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Stefan Kölker
- Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Georg F Hoffmann
- Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Min-Joon Han
- The F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Franck Polleux
- Department of Neuroscience, Zuckerman Mind Brain Behavior Institute and Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Mustafa Sahin
- The F.M. Kirby Neurobiology Center, Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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223
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Misgeld T, Schwarz TL. Mitostasis in Neurons: Maintaining Mitochondria in an Extended Cellular Architecture. Neuron 2017; 96:651-666. [PMID: 29096078 DOI: 10.1016/j.neuron.2017.09.055] [Citation(s) in RCA: 321] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 09/25/2017] [Accepted: 09/28/2017] [Indexed: 02/06/2023]
Abstract
Neurons have more extended and complex shapes than other cells and consequently face a greater challenge in distributing and maintaining mitochondria throughout their arbors. Neurons can last a lifetime, but proteins turn over rapidly. Mitochondria, therefore, need constant rejuvenation no matter how far they are from the soma. Axonal transport of mitochondria and mitochondrial fission and fusion contribute to this rejuvenation, but local protein synthesis is also likely. Maintenance of a healthy mitochondrial population also requires the clearance of damaged proteins and organelles. This involves degradation of individual proteins, sequestration in mitochondria-derived vesicles, organelle degradation by mitophagy and macroautophagy, and in some cases transfer to glial cells. Both long-range transport and local processing are thus at work in achieving neuronal mitostasis-the maintenance of an appropriately distributed pool of healthy mitochondria for the duration of a neuron's life. Accordingly, defects in the processes that support mitostasis are significant contributors to neurodegenerative disorders.
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Affiliation(s)
- Thomas Misgeld
- Technical University of Munich, Institute of Neuronal Cell Biology, Munich, Germany; German Center for Neurodegenerative Diseases, Munich, Germany; Munich Cluster for Systems Neurology, Munich, Germany; Center of Integrated Protein Science, Munich, Germany.
| | - Thomas L Schwarz
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA; F.M. Kirby Neurobiology Center, Children's Hospital, Boston, MA, USA.
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224
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Jackson JG, Robinson MB. Regulation of mitochondrial dynamics in astrocytes: Mechanisms, consequences, and unknowns. Glia 2017; 66:1213-1234. [PMID: 29098734 DOI: 10.1002/glia.23252] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 09/20/2017] [Accepted: 10/09/2017] [Indexed: 12/15/2022]
Abstract
Astrocytes are the major glial cell in the central nervous system. These polarized cells possess numerous processes that ensheath the vasculature and contact synapses. Astrocytes play important roles in synaptic signaling, neurotransmitter synthesis and recycling, control of nutrient uptake, and control of local blood flow. Many of these processes depend on local metabolism and/or energy utilization. While astrocytes respond to increases in neuronal activity and metabolic demand by upregulating glycolysis and glycogenolysis, astrocytes also possess significant capacity for oxidative (mitochondrial) metabolism. Mitochondria mediate energy supply and metabolism, cellular survival, ionic homeostasis, and proliferation. These organelles are dynamic structures undergoing extensive fission and fusion, directed movement along cytoskeletal tracts, and degradation. While many of the mechanisms underlying the dynamics of these organelles and their physiologic roles have been characterized in neurons and other cells, the roles that mitochondrial dynamics play in glial physiology is less well understood. Recent work from several laboratories has demonstrated that mitochondria are present within the fine processes of astrocytes, that their movement is regulated, and that they contribute to local Ca2+ signaling within the astrocyte. They likely play a role in local ATP production and metabolism, particularly that of glutamate. Here we will review these and other findings describing the mechanism by which mitochondrial dynamics are regulated in astrocytes, how mitochondrial dynamics might influence astrocyte and brain metabolism, and draw parallels to mitochondrial dynamics in neurons. Additionally, we present new analyses of the size, distribution, and dynamics of mitochondria in astrocytes performed using in vivo using 2-photon microscopy.
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Affiliation(s)
- Joshua G Jackson
- Children's Hospital of Philadelphia Research Institute, University of Pennsylvania, Philadelphia, PA, 19104.,Departments of Pediatrics, University of Pennsylvania, Philadelphia, PA, 19104
| | - Michael B Robinson
- Children's Hospital of Philadelphia Research Institute, University of Pennsylvania, Philadelphia, PA, 19104.,Departments of Pediatrics, University of Pennsylvania, Philadelphia, PA, 19104.,Department of Pharmacology, University of Pennsylvania, Philadelphia, PA, 19104
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225
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Djeungoue-Petga MA, Hebert-Chatelain E. Linking Mitochondria and Synaptic Transmission: The CB1 Receptor. Bioessays 2017; 39. [PMID: 29058339 DOI: 10.1002/bies.201700126] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 09/19/2017] [Indexed: 12/21/2022]
Abstract
CB1 receptors are functionally present within brain mitochondria (mtCB1), although they are usually considered specifically targeted to plasma membrane. Acute activation of mtCB1 alters mitochondrial ATP generation, synaptic transmission, and memory performance. However, the detailed mechanism linking disrupted mitochondrial metabolism and synaptic transmission is still uncharacterized. CB1 receptors are among the most abundant G protein-coupled receptors in the brain and impact on several processes, including fear coping, anxiety, stress, learning, and memory. Mitochondria perform several key physiological processes for neuronal homeostasis, including production of ATP and reactive oxygen species, calcium buffering, metabolism of neurotransmitters, and apoptosis. It is therefore possible that acute activation of mtCB1 impacts on these different mitochondrial functions to modulate synaptic transmission. In reviewing and integrating across the literature in this area, we describe the possible mechanisms involved in the regulation of brain physiology by mtCB1 receptors.
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Affiliation(s)
| | - Etienne Hebert-Chatelain
- Department of Biology, Université de Moncton, 18 Av Antonine Maillet, Moncton, New Brunswick, Canada
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226
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Napoli E, Song G, Liu S, Espejo A, Perez CJ, Benavides F, Giulivi C. Zdhhc13-dependent Drp1 S-palmitoylation impacts brain bioenergetics, anxiety, coordination and motor skills. Sci Rep 2017; 7:12796. [PMID: 29038583 PMCID: PMC5643561 DOI: 10.1038/s41598-017-12889-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 09/14/2017] [Indexed: 01/14/2023] Open
Abstract
Protein S-palmitoylation is a reversible post-translational modification mediated by palmitoyl acyltransferase enzymes, a group of Zn2+-finger DHHC-domain-containing proteins (ZDHHC). Here, for the first time, we show that Zdhhc13 plays a key role in anxiety-related behaviors and motor function, as well as brain bioenergetics, in a mouse model (luc) carrying a spontaneous Zdhhc13 recessive mutation. At 3 m of age, mutant mice displayed increased sensorimotor gating, anxiety, hypoactivity, and decreased motor coordination, compared to littermate controls. Loss of Zdhhc13 in cortex and cerebellum from 3- and 24 m old hetero- and homozygous male mutant mice resulted in lower levels of Drp1 S-palmitoylation accompanied by altered mitochondrial dynamics, increased glycolysis, glutaminolysis and lactic acidosis, and neurotransmitter imbalances. Employing in vivo and in vitro models, we identified that Zdhhc13-dependent Drp1 S-palmitoylation, which acting alone or in concert, enables the normal occurrence of the fission-fusion process. In vitro and in vivo direct Zdhhc13-Drp1 protein interaction was observed, confirming Drp1 as a substrate of Zdhhc13. Abnormal fission-fusion processes result in disrupted mitochondria morphology and distribution affecting not only mitochondrial ATP output but neurotransmission and integrity of synaptic structures in the brain, setting the basis for the behavioral abnormalities described in the Zdhhc13-deficient mice.
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Affiliation(s)
- Eleonora Napoli
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, 95616, USA
| | - Gyu Song
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, 95616, USA
| | - Siming Liu
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, 95616, USA
| | - Alexsandra Espejo
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, 77030, USA
| | - Carlos J Perez
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, 77030, USA
| | - Fernando Benavides
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, 77030, USA
| | - Cecilia Giulivi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, 95616, USA. .,Medical Investigations of Neurodevelopmental Disorders (MIND) Institute, University of California Davis, Davis, CA, 95817, USA.
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227
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Hyperglycemia exacerbates downregulation of dynamin-like protein 1 in ischemic cerebral injury. Lab Anim Res 2017; 33:202-208. [PMID: 29046694 PMCID: PMC5645597 DOI: 10.5625/lar.2017.33.3.202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 09/06/2017] [Accepted: 09/06/2017] [Indexed: 01/24/2023] Open
Abstract
Ischemic stroke is one of the leading causes of adult disability and death. Hyperglycemia is associated with an increased risk of stroke and poor outcomes after brain injury. Dynamin-like protein I (DLP-1) regulates mitochondrial fission and promotes mitochondrial dynamics. Neurodegenerative diseases are associated with mitochondrial dysfunction, and the downregulation of DLP-1 has been previously identified in a stroke animal model. Here, we investigated the changes in DLP-1 protein expression in an animal model of focal cerebral ischemia with induced hyperglycemia. Streptozotocin (40 mg/kg) was intraperitoneally injected into male rats to induce hyperglycemia, and middle cerebral artery occlusion (MCAO) was surgically induced 4 weeks after streptozotocin treatment. Brain tissue was isolated 24 hours after MCAO, and cerebral cortex samples were used for this study. Proteomics revealed a decrease in DLP-1 expression in MCAO animals when compared with controls, and this downregulation was more prominent in MCAO animals with hyperglycemia. Reverse-transcription polymerase chain reaction and Western blot analyses confirmed that DLP-1 was significantly downregulated in MCAO-injured animals with hyperglycemia compared to those without hyperglycemia. The decrease in DLP-1 indicates mitochondrial morphological changes and dysfunction. Together, these results suggest that the severe decrease of DLP-1 seen after brain injury under hyperglycemic conditions may exacerbate the damage to the brain.
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228
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Amorim JA, Canas PM, Tomé AR, Rolo AP, Agostinho P, Palmeira CM, Cunha RA. Mitochondria in Excitatory and Inhibitory Synapses have Similar Susceptibility to Amyloid-β Peptides Modeling Alzheimer’s Disease. J Alzheimers Dis 2017; 60:525-536. [DOI: 10.3233/jad-170356] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- João A. Amorim
- CNC – Center for Neuroscience and Cell Biology, University of Coimbra, Portugal
| | - Paula M. Canas
- CNC – Center for Neuroscience and Cell Biology, University of Coimbra, Portugal
| | - Angelo R. Tomé
- CNC – Center for Neuroscience and Cell Biology, University of Coimbra, Portugal
- Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Portugal
| | - Anabela P. Rolo
- CNC – Center for Neuroscience and Cell Biology, University of Coimbra, Portugal
- Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Portugal
| | - Paula Agostinho
- CNC – Center for Neuroscience and Cell Biology, University of Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Portugal
| | - Carlos M. Palmeira
- CNC – Center for Neuroscience and Cell Biology, University of Coimbra, Portugal
- Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Portugal
| | - Rodrigo A. Cunha
- CNC – Center for Neuroscience and Cell Biology, University of Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Portugal
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229
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Roberts RC. Postmortem studies on mitochondria in schizophrenia. Schizophr Res 2017; 187:17-25. [PMID: 28189530 PMCID: PMC5550365 DOI: 10.1016/j.schres.2017.01.056] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 01/27/2017] [Accepted: 01/30/2017] [Indexed: 01/02/2023]
Abstract
The aim of this paper is to provide a brief review of mitochondrial structure as it relates to function and then present abnormalities in mitochondria in postmortem schizophrenia with a focus on ultrastructure. Function, morphology, fusion, fission, motility, ΔΨmem, ATP production, mitochondrial derived vesicles, and mitochondria-associated ER membranes will be briefly covered. Pathology in mitochondria has long been implicated in schizophrenia, as shown by genetic, proteomic, enzymatic and anatomical abnormalities. The cortex and basal ganglia will be reviewed. In the anterior cingulate cortex, the number of mitochondria per neuronal somata in layers 5/6 in schizophrenia is decreased by 43%. There are also fewer mitochondria in terminals forming axospinous synapses. In the caudate and putamen the number of mitochondria is abnormal in both glial cells and neurons in schizophrenia subjects, the extent of which depends on treatment, response and predominant lifetime symptoms. Treatment-responsive schizophrenia subjects had about a 40% decrease in the number of mitochondria per synapse in the caudate nucleus and putamen, while treatment resistant cases had normal values. A decrease in mitochondrial density in the neuropil distinguishes paranoid from undifferentiated schizophrenia. The appearance, size and density of mitochondria were normal in the nucleus accumbens. In the substantia nigra, COX subunits were affected in rostral regions. Mitochondrial hyperplasia occurs within axon terminals that synapse onto dopamine neurons, but mitochondria in dopamine neuronal somata are similar in size and number. In schizophrenia, mitochondria are differentially affected depending on the brain region, cell type, subcellular location, treatment status, treatment response and symptoms.
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Affiliation(s)
- Rosalinda C. Roberts
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama, Birmingham, AL 35294
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230
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Bykhovskaia M, Vasin A. Electrophysiological analysis of synaptic transmission in Drosophila. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2017; 6:10.1002/wdev.277. [PMID: 28544556 PMCID: PMC5980642 DOI: 10.1002/wdev.277] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 03/22/2017] [Accepted: 04/14/2017] [Indexed: 01/10/2023]
Abstract
Synaptic transmission is dynamic, plastic, and highly regulated. Drosophila is an advantageous model system for genetic and molecular studies of presynaptic and postsynaptic mechanisms and plasticity. Electrical recordings of synaptic responses represent a wide-spread approach to study neuronal signaling and synaptic transmission. We discuss experimental techniques that allow monitoring synaptic transmission in Drosophila neuromuscular and central systems. Recordings of synaptic potentials or currents at the larval neuromuscular junction (NMJ) are most common and provide numerous technical advantages due to robustness of the preparation, large and identifiable muscles, and synaptic boutons which can be readily visualized. In particular, focal macropatch recordings combined with the analysis of neurosecretory quanta enable rigorous quantification of the magnitude and kinetics of transmitter release. Patch-clamp recordings of synaptic transmission from the embryonic NMJ enable overcoming the problem of lethality in mutant lines. Recordings from the adult NMJ proved instrumental in the studies of temperature-sensitive paralytic mutants. Genetic studies of behavioral learning in Drosophila compel an investigation of synaptic transmission in the central nervous system (CNS), including primary cultured neurons and an intact brain. Cholinergic and GABAergic synaptic transmission has been recorded from the Drosophila CNS both in vitro and in vivo. In vivo patch-clamp recordings of synaptic transmission from the neurons in the olfactory pathway is a very powerful approach, which has a potential to elucidate how synaptic transmission is associated with behavioral learning. WIREs Dev Biol 2017, 6:e277. doi: 10.1002/wdev.277 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
| | - Alexander Vasin
- Department of Neurology, Wayne State University, Detroit, MI, USA
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231
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Han SM, Baig HS, Hammarlund M. Mitochondria Localize to Injured Axons to Support Regeneration. Neuron 2017; 92:1308-1323. [PMID: 28009276 DOI: 10.1016/j.neuron.2016.11.025] [Citation(s) in RCA: 159] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 08/31/2016] [Accepted: 11/08/2016] [Indexed: 12/19/2022]
Abstract
Axon regeneration is essential to restore the nervous system after axon injury. However, the neuronal cell biology that underlies axon regeneration is incompletely understood. Here we use in vivo, single-neuron analysis to investigate the relationship between nerve injury, mitochondrial localization, and axon regeneration. Mitochondria translocate into injured axons so that average mitochondria density increases after injury. Moreover, single-neuron analysis reveals that axons that fail to increase mitochondria have poor regeneration. Experimental alterations to axonal mitochondrial distribution or mitochondrial respiratory chain function result in corresponding changes to regeneration outcomes. Axonal mitochondria are specifically required for growth-cone migration, identifying a key energy challenge for injured neurons. Finally, mitochondrial localization to the axon after injury is regulated in part by dual-leucine zipper kinase 1 (DLK-1), a conserved regulator of axon regeneration. These data identify regulation of axonal mitochondria as a new cell-biological mechanism that helps determine the regenerative response of injured neurons.
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Affiliation(s)
- Sung Min Han
- Departments of Genetics and Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Huma S Baig
- Departments of Genetics and Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Marc Hammarlund
- Departments of Genetics and Neuroscience, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA.
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232
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Compartmentalized Regulation of Parkin-Mediated Mitochondrial Quality Control in the Drosophila Nervous System In Vivo. J Neurosci 2017; 36:7375-91. [PMID: 27413149 DOI: 10.1523/jneurosci.0633-16.2016] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 05/18/2016] [Indexed: 12/14/2022] Open
Abstract
UNLABELLED In neurons, the normal distribution and selective removal of mitochondria are considered essential for maintaining the functions of the large asymmetric cell and its diverse compartments. Parkin, a E3 ubiquitin ligase associated with familial Parkinson's disease, has been implicated in mitochondrial dynamics and removal in cells including neurons. However, it is not clear how Parkin functions in mitochondrial turnover in vivo, or whether Parkin-dependent events of the mitochondrial life cycle occur in all neuronal compartments. Here, using the live Drosophila nervous system, we investigated the involvement of Parkin in mitochondrial dynamics, distribution, morphology, and removal. Contrary to our expectations, we found that Parkin-deficient animals do not accumulate senescent mitochondria in their motor axons or neuromuscular junctions; instead, they contain far fewer axonal mitochondria, and these displayed normal motility behavior, morphology, and metabolic state. However, the loss of Parkin did produce abnormal tubular and reticular mitochondria restricted to the motor cell bodies. In addition, in contrast to drug-treated, immortalized cells in vitro, mature motor neurons rarely displayed Parkin-dependent mitophagy. These data indicate that the cell body is the focus of Parkin-dependent mitochondrial quality control in neurons, and argue that a selection process allows only healthy mitochondria to pass from cell bodies to axons, perhaps to limit the impact of mitochondrial dysfunction. SIGNIFICANCE STATEMENT Parkin has been proposed to police mitochondrial fidelity by binding to dysfunctional mitochondria via PTEN (phosphatase and tensin homolog)-induced putative kinase 1 (PINK1) and targeting them for autophagic degradation. However, it is unknown whether and how the PINK1/Parkin pathway regulates the mitochondrial life cycle in neurons in vivo Using Drosophila motor neurons, we show that parkin disruption generates an abnormal mitochondrial network in cell bodies in vivo and reduces the number of axonal mitochondria without producing any defects in their axonal transport, morphology, or metabolic state. Furthermore, while cultured neurons display Parkin-dependent axonal mitophagy, we find this is vanishingly rare in vivo under normal physiological conditions. Thus, both the spatial distribution and mechanism of mitochondrial quality control in vivo differ substantially from those observed in vitro.
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233
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Phosphorylation of Synaptojanin Differentially Regulates Endocytosis of Functionally Distinct Synaptic Vesicle Pools. J Neurosci 2017; 36:8882-94. [PMID: 27559170 DOI: 10.1523/jneurosci.1470-16.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 07/14/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED The rapid replenishment of synaptic vesicles through endocytosis is crucial for sustaining synaptic transmission during intense neuronal activity. Synaptojanin (Synj), a phosphoinositide phosphatase, is known to play an important role in vesicle recycling by promoting the uncoating of clathrin following synaptic vesicle uptake. Synj has been shown to be a substrate of the minibrain (Mnb) kinase, a fly homolog of the dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A); however, the functional impacts of Synj phosphorylation by Mnb are not well understood. Here we identify that Mnb phosphorylates Synj at S1029 in Drosophila We find that phosphorylation of Synj at S1029 enhances Synj phosphatase activity, alters interaction between Synj and endophilin, and promotes efficient endocytosis of the active cycling vesicle pool (also referred to as exo-endo cycling pool) at the expense of reserve pool vesicle endocytosis. Dephosphorylated Synj, on the other hand, is deficient in the endocytosis of the active recycling pool vesicles but maintains reserve pool vesicle endocytosis to restore total vesicle pool size and sustain synaptic transmission. Together, our findings reveal a novel role for Synj in modulating reserve pool vesicle endocytosis and further indicate that dynamic phosphorylation and dephosphorylation of Synj differentially maintain endocytosis of distinct functional synaptic vesicle pools. SIGNIFICANCE STATEMENT Synaptic vesicle endocytosis sustains communication between neurons during a wide range of neuronal activities by recycling used vesicle membrane and protein components. Here we identify that Synaptojanin, a protein with a known role in synaptic vesicle endocytosis, is phosphorylated at S1029 in vivo by the Minibrain kinase. We further demonstrate that the phosphorylation status of Synaptojanin at S1029 differentially regulates its participation in the recycling of distinct synaptic vesicle pools. Our results reveal a new role for Synaptojanin in maintaining synaptic vesicle pool size and in reserve vesicle endocytosis. As Synaptojanin and Minibrain perturbations are associated with various neurological disorders, such as Parkinson's, autism, and Down syndrome, understanding mechanisms modulating Synaptojanin function provides valuable insights into processes affecting neuronal communication.
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234
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Lavie J, Serrat R, Bellance N, Courtand G, Dupuy JW, Tesson C, Coupry I, Brice A, Lacombe D, Durr A, Stevanin G, Darios F, Rossignol R, Goizet C, Bénard G. Mitochondrial morphology and cellular distribution are altered in SPG31 patients and are linked to DRP1 hyperphosphorylation. Hum Mol Genet 2017; 26:674-685. [PMID: 28007911 DOI: 10.1093/hmg/ddw425] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 12/12/2016] [Indexed: 01/07/2023] Open
Abstract
Hereditary spastic paraplegia, SPG31, is a rare neurological disorder caused by mutations in REEP1 gene encoding the microtubule-interacting protein, REEP1. The mechanism by which REEP1-dependent processes are linked with the disease is unclear. REEP1 regulates the morphology and trafficking of various organelles via interaction with the microtubules. In this study, we collected primary fibroblasts from SPG31 patients to investigate their mitochondrial morphology. We observed that the mitochondrial morphology in patient cells was highly tubular compared with control cells. We provide evidence that these morphological alterations are caused by the inhibition of mitochondrial fission protein, DRP1, due to the hyperphosphorylation of its serine 637 residue. This hyperphosphorylation is caused by impaired interactions between REEP1 and mitochondrial phosphatase PGAM5. Genetically or pharmacologically induced decrease of DRP1-S637 phosphorylation restores mitochondrial morphology in patient cells. Furthermore, ectopic expression of REEP1 carrying pathological mutations in primary neuronal culture targets REEP1 to the mitochondria. Mutated REEP1 proteins sequester mitochondria to the perinuclear region of the neurons and therefore, hamper mitochondrial transport along the axon. Considering the established role of mitochondrial distribution and morphology in neuronal health, our results support the involvement of a mitochondrial dysfunction in SPG31 pathology.
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Affiliation(s)
- Julie Lavie
- INSERM U1211, Laboratoire Maladies Rares: Génétique et Métabolisme. Hôpital Pellegrin, 33000 Bordeaux, France.,University of Bordeaux, 33077 Bordeaux, France
| | - Román Serrat
- University of Bordeaux, 33077 Bordeaux, France.,INSERM U1215, NeuroCentre Magendie, 33077 Bordeaux, France
| | - Nadège Bellance
- INSERM U1211, Laboratoire Maladies Rares: Génétique et Métabolisme. Hôpital Pellegrin, 33000 Bordeaux, France.,University of Bordeaux, 33077 Bordeaux, France
| | - Gilles Courtand
- University of Bordeaux, 33077 Bordeaux, France.,INCIA, Université de Bordeaux, CNRS UMR5287, Bordeaux, France
| | - Jean-William Dupuy
- University of Bordeaux, 33077 Bordeaux, France.,Plateforme Protéome, Centre de Génomique Fonctionnelle, F-33000 Bordeaux, France
| | - Christelle Tesson
- INSERM U1127, CNRS UMR 7225, UPMC Université Paris 06 UMR S1127, Sorbonne Université Institut du Cerveau et de la Moelle épinière, ICM F-75013, Paris, France.,Ecole Pratique des Hautes Etudes, PSL Research University, 75014 Paris, France
| | - Isabelle Coupry
- INSERM U1211, Laboratoire Maladies Rares: Génétique et Métabolisme. Hôpital Pellegrin, 33000 Bordeaux, France.,University of Bordeaux, 33077 Bordeaux, France
| | - Alexis Brice
- INSERM U1127, CNRS UMR 7225, UPMC Université Paris 06 UMR S1127, Sorbonne Université Institut du Cerveau et de la Moelle épinière, ICM F-75013, Paris, France
| | - Didier Lacombe
- INSERM U1211, Laboratoire Maladies Rares: Génétique et Métabolisme. Hôpital Pellegrin, 33000 Bordeaux, France.,University of Bordeaux, 33077 Bordeaux, France
| | - Alexandra Durr
- INSERM U1127, CNRS UMR 7225, UPMC Université Paris 06 UMR S1127, Sorbonne Université Institut du Cerveau et de la Moelle épinière, ICM F-75013, Paris, France
| | - Giovanni Stevanin
- INSERM U1127, CNRS UMR 7225, UPMC Université Paris 06 UMR S1127, Sorbonne Université Institut du Cerveau et de la Moelle épinière, ICM F-75013, Paris, France.,Ecole Pratique des Hautes Etudes, PSL Research University, 75014 Paris, France
| | - Fréderic Darios
- INSERM U1127, CNRS UMR 7225, UPMC Université Paris 06 UMR S1127, Sorbonne Université Institut du Cerveau et de la Moelle épinière, ICM F-75013, Paris, France
| | - Rodrigue Rossignol
- INSERM U1211, Laboratoire Maladies Rares: Génétique et Métabolisme. Hôpital Pellegrin, 33000 Bordeaux, France.,University of Bordeaux, 33077 Bordeaux, France
| | - Cyril Goizet
- INSERM U1211, Laboratoire Maladies Rares: Génétique et Métabolisme. Hôpital Pellegrin, 33000 Bordeaux, France.,University of Bordeaux, 33077 Bordeaux, France
| | - Giovanni Bénard
- INSERM U1211, Laboratoire Maladies Rares: Génétique et Métabolisme. Hôpital Pellegrin, 33000 Bordeaux, France.,University of Bordeaux, 33077 Bordeaux, France
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235
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Tao J, Bulgari D, Deitcher DL, Levitan ES. Limited distal organelles and synaptic function in extensive monoaminergic innervation. J Cell Sci 2017; 130:2520-2529. [PMID: 28600320 DOI: 10.1242/jcs.201111] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 06/05/2017] [Indexed: 12/20/2022] Open
Abstract
Organelles such as neuropeptide-containing dense-core vesicles (DCVs) and mitochondria travel down axons to supply synaptic boutons. DCV distribution among en passant boutons in small axonal arbors is mediated by circulation with bidirectional capture. However, it is not known how organelles are distributed in extensive arbors associated with mammalian dopamine neuron vulnerability, and with volume transmission and neuromodulation by monoamines and neuropeptides. Therefore, we studied presynaptic organelle distribution in Drosophila octopamine neurons that innervate ∼20 muscles with ∼1500 boutons. Unlike in smaller arbors, distal boutons in these arbors contain fewer DCVs and mitochondria, although active zones are present. Absence of vesicle circulation is evident by proximal nascent DCV delivery, limited impact of retrograde transport and older distal DCVs. Traffic studies show that DCV axonal transport and synaptic capture are not scaled for extensive innervation, thus limiting distal delivery. Activity-induced synaptic endocytosis and synaptic neuropeptide release are also reduced distally. We propose that limits in organelle transport and synaptic capture compromise distal synapse maintenance and function in extensive axonal arbors, thereby affecting development, plasticity and vulnerability to neurodegenerative disease.
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Affiliation(s)
- Juan Tao
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Dinara Bulgari
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - David L Deitcher
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - Edwin S Levitan
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
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236
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Srivastav S, Fatima M, Mondal AC. Important medicinal herbs in Parkinson's disease pharmacotherapy. Biomed Pharmacother 2017; 92:856-863. [PMID: 28599249 DOI: 10.1016/j.biopha.2017.05.137] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 05/10/2017] [Accepted: 05/28/2017] [Indexed: 11/28/2022] Open
Abstract
Parkinson's disease (PD) is the most common progressive neurodegenerative movement disorder affecting more than 10 million people worldwide. The characteristic hallmark of PD involves progressive loss of dopaminergic (DA-ergic) neuron in Substantia Nigra pars compacta (SNpc) region of the brain, however, aetiology of the disease still remains unclear. Mitochondrial dysfunction and oxidative insult are considered to be the key culprit. The current therapy available for PD primarily relies on Levodopa that offers the potential of slowing down disease progression to some extent but includes lot of side effects. Any potential drug capable of treating or halting the disease still remains to be identified. It is evident that redox stabilization and replenishment of mitochondrial function seem to be an important therapeutic approach against PD as both are required for optimal neuronal functioning. Enormous research done in this field has shown that some natural and synthetic products exhibit neuroprotective and anti-apoptotic potential by improving mitochondrial function and alleviating oxidative stress. Therefore, the present review aims to discuss some of the important medicinal natural herbs (Bacopa monnieri, Mucuna pruriens, Withania somnifera, Curcuma longa, Gingko Biloba, and Camellia sinensis) in context to their neuroprotective potential and also in the development of novel therapeutic strategies against PD.
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Affiliation(s)
- Saurabh Srivastav
- Laboratory of Cellular & Molecular Neurobiology, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Mahino Fatima
- Laboratory of Cellular & Molecular Neurobiology, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Amal Chandra Mondal
- Laboratory of Cellular & Molecular Neurobiology, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
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237
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Sheng ZH. The Interplay of Axonal Energy Homeostasis and Mitochondrial Trafficking and Anchoring. Trends Cell Biol 2017; 27:403-416. [PMID: 28228333 PMCID: PMC5440189 DOI: 10.1016/j.tcb.2017.01.005] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 01/15/2017] [Accepted: 01/20/2017] [Indexed: 01/02/2023]
Abstract
Mitochondria are key cellular power plants essential for neuronal growth, survival, function, and regeneration after injury. Given their unique morphological features, neurons face exceptional challenges in maintaining energy homeostasis at distal synapses and growth cones where energy is in high demand. Efficient regulation of mitochondrial trafficking and anchoring is critical for neurons to meet altered energy requirements. Mitochondrial dysfunction and impaired transport have been implicated in several major neurological disorders. Thus, research into energy-mediated regulation of mitochondrial recruitment and redistribution is an important emerging frontier. In this review, I discuss new insights into the mechanisms regulating mitochondrial trafficking and anchoring, and provide an updated overview of how mitochondrial motility maintains energy homeostasis in axons, thus contributing to neuronal growth, regeneration, and synaptic function.
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Affiliation(s)
- Zu-Hang Sheng
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Room 2B-215, 35 Convent Drive, Bethesda, MD 20892-3706, USA.
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238
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Fedorovich SV, Waseem TV, Puchkova LV. Biogenetic and morphofunctional heterogeneity of mitochondria: the case of synaptic mitochondria. Rev Neurosci 2017; 28:363-373. [DOI: 10.1515/revneuro-2016-0077] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 12/29/2016] [Indexed: 12/26/2022]
Abstract
AbstractThe mitochondria of different cells are different in their morphological and biochemical properties. These organelles generate free radicals during activity, leading inevitably to mitochondrial DNA damage. It is not clear how this problem is addressed in long-lived cells, such as neurons. We propose the hypothesis that mitochondria within the same cell also differ in lifespan and ability to divide. According to our suggestion, cells have a pool of ‘stem’ mitochondria with low metabolic activity and a pool of ‘differentiated’ mitochondria with significantly shorter lifespans and high metabolic activity. We consider synaptic mitochondria as a possible example of ‘differentiated’ mitochondria. They are significantly smaller than mitochondria from the cell body, and they are different in key enzyme activity levels, proteome, and lipidome. Synaptic mitochondria are more sensitive to different damaging factors. It has been established that neurons have a sorting mechanism that sends mitochondria with high membrane potential to presynaptic endings. This review describes the properties of synaptic mitochondria and their role in the regulation of synaptic transmission.
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Affiliation(s)
- Sergei V. Fedorovich
- Institute of Biophysics and Cell Engineering, Akademicheskaya St., 27, Minsk 220072, Belarus
| | - Tatyana V. Waseem
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Ludmila V. Puchkova
- Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya str., 29, St. Petersburg 195251, Russia
- ITMO University, Kronverksky av., 49, St.Petersburg 197101, Russia
- Institute of Experimental Medicine, Pavlova str., 12, St.Petersburg 197376, Russia
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239
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Improvement of mitochondrial function mediated the neuroprotective effect of 5-(4-hydroxy-3-dimethoxybenzylidene)-2-thioxo-4-thiazolidinone in rats with cerebral ischemia-reperfusion injuries. Oncotarget 2017; 8:61193-61202. [PMID: 28977856 PMCID: PMC5617416 DOI: 10.18632/oncotarget.18048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 04/25/2017] [Indexed: 11/25/2022] Open
Abstract
Deficits in mitochondrial function is a critical inducement in the major pathways that drive neuronal cell death in ischemic process particularly. Drugs target to improve the mitochondrial function may be a feasible therapeutic choice in treatment with ischemic diseases. In the present study, we investigated whether 5-(4-hydroxy-3-dimethoxybenzylidene)-2-thioxo-4-thiazolidinone (RD-1), a compound derived from rhodanine, could protect against ischemic neuronal damage via improving mitochondrial function. We tested the neuroprotective effect of RD-1 both in rats modeled by middle cerebral artery occlusion reperfusion in vivo and in primary cortical neurons subjected to hypoxia/reperfusion injury in vitro. Results showed that treatment with RD-1 for 14 days remarkably reduced infarct size, decreased neurological deficit score and accelerated the recovery of somatosensory function in vivo. Meanwhile, RD-1 also increased the cellular viability after 48 h treatment in vitro. In addition, RD-1 protected the primary cortical neurons against mitochondrial damage as evidenced by stabilizing the mitochondrial membrane potential and reducing the overproduction of reactive oxygen species. Furthermore, hypoxia/reperfusion injury induced damaged mitochondrial axonal transport and consequently neurotransmitter release disorder, which were ameliorated by RD-1 treatment. Besides, RD-1 inhibited the downregulation of proteins related with mitochondrial transport and neurotransmitter release induced by ischemic injury both in vivo and in vitro. The obtained data demonstrated the neuroprotective effect of RD-1 and the involved mechanisms were partially attributed to the improvement in mitochondrial function and the synaptic activity. Our study indicated that RD-1 may be a potential therapeutic drug for the ischemic stroke therapy.
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240
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Liao PC, Tandarich LC, Hollenbeck PJ. ROS regulation of axonal mitochondrial transport is mediated by Ca2+ and JNK in Drosophila. PLoS One 2017; 12:e0178105. [PMID: 28542430 PMCID: PMC5436889 DOI: 10.1371/journal.pone.0178105] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 05/06/2017] [Indexed: 12/31/2022] Open
Abstract
Mitochondria perform critical functions including aerobic ATP production and calcium (Ca2+) homeostasis, but are also a major source of reactive oxygen species (ROS) production. To maintain cellular function and survival in neurons, mitochondria are transported along axons, and accumulate in regions with high demand for their functions. Oxidative stress and abnormal mitochondrial axonal transport are associated with neurodegenerative disorders. However, we know little about the connection between these two. Using the Drosophila third instar larval nervous system as the in vivo model, we found that ROS inhibited mitochondrial axonal transport more specifically, primarily due to reduced flux and velocity, but did not affect transport of other organelles. To understand the mechanisms underlying these effects, we examined Ca2+ levels and the JNK (c-Jun N-terminal Kinase) pathway, which have been shown to regulate mitochondrial transport and general fast axonal transport, respectively. We found that elevated ROS increased Ca2+ levels, and that experimental reduction of Ca2+ to physiological levels rescued ROS-induced defects in mitochondrial transport in primary neuron cell cultures. In addition, in vivo activation of the JNK pathway reduced mitochondrial flux and velocities, while JNK knockdown partially rescued ROS-induced defects in the anterograde direction. We conclude that ROS have the capacity to regulate mitochondrial traffic, and that Ca2+ and JNK signaling play roles in mediating these effects. In addition to transport defects, ROS produces imbalances in mitochondrial fission-fusion and metabolic state, indicating that mitochondrial transport, fission-fusion steady state, and metabolic state are closely interrelated in the response to ROS.
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Affiliation(s)
- Pin-Chao Liao
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - Lauren C. Tandarich
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - Peter J. Hollenbeck
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
- * E-mail:
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241
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Zhou L, McInnes J, Wierda K, Holt M, Herrmann AG, Jackson RJ, Wang YC, Swerts J, Beyens J, Miskiewicz K, Vilain S, Dewachter I, Moechars D, De Strooper B, Spires-Jones TL, De Wit J, Verstreken P. Tau association with synaptic vesicles causes presynaptic dysfunction. Nat Commun 2017; 8:15295. [PMID: 28492240 PMCID: PMC5437271 DOI: 10.1038/ncomms15295] [Citation(s) in RCA: 240] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 03/17/2017] [Indexed: 12/18/2022] Open
Abstract
Tau is implicated in more than 20 neurodegenerative diseases, including Alzheimer's disease. Under pathological conditions, Tau dissociates from axonal microtubules and missorts to pre- and postsynaptic terminals. Patients suffer from early synaptic dysfunction prior to Tau aggregate formation, but the underlying mechanism is unclear. Here we show that pathogenic Tau binds to synaptic vesicles via its N-terminal domain and interferes with presynaptic functions, including synaptic vesicle mobility and release rate, lowering neurotransmission in fly and rat neurons. Pathological Tau mutants lacking the vesicle binding domain still localize to the presynaptic compartment but do not impair synaptic function in fly neurons. Moreover, an exogenously applied membrane-permeable peptide that competes for Tau-vesicle binding suppresses Tau-induced synaptic toxicity in rat neurons. Our work uncovers a presynaptic role of Tau that may be part of the early pathology in various Tauopathies and could be exploited therapeutically.
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Affiliation(s)
- Lujia Zhou
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Joseph McInnes
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Keimpe Wierda
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Matthew Holt
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Abigail G. Herrmann
- University of Edinburgh, Centre for Cognitive and Neural Systems, Center for Dementia Prevention and Euan MacDonald Centre, Edinburgh EH8 9JZ, UK
| | - Rosemary J. Jackson
- University of Edinburgh, Centre for Cognitive and Neural Systems, Center for Dementia Prevention and Euan MacDonald Centre, Edinburgh EH8 9JZ, UK
| | - Yu-Chun Wang
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Jef Swerts
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Jelle Beyens
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Katarzyna Miskiewicz
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Sven Vilain
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Ilse Dewachter
- Catholic University of Louvain, Alzheimer Dementia Group, Institute of Neuroscience, Brussels 1200, Belgium
- University of Hasselt, Biomedical Research Institute, Hasselt 3500, Belgium
| | - Diederik Moechars
- A Division of Janssen Pharmaceutica NV, Neuroscience Department, Janssen Research and Development, Beerse 2340, Belgium
| | - Bart De Strooper
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Tara L. Spires-Jones
- University of Edinburgh, Centre for Cognitive and Neural Systems, Center for Dementia Prevention and Euan MacDonald Centre, Edinburgh EH8 9JZ, UK
| | - Joris De Wit
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Patrik Verstreken
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
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242
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Boyd PJ, Tu WY, Shorrock HK, Groen EJN, Carter RN, Powis RA, Thomson SR, Thomson D, Graham LC, Motyl AAL, Wishart TM, Highley JR, Morton NM, Becker T, Becker CG, Heath PR, Gillingwater TH. Bioenergetic status modulates motor neuron vulnerability and pathogenesis in a zebrafish model of spinal muscular atrophy. PLoS Genet 2017; 13:e1006744. [PMID: 28426667 PMCID: PMC5417717 DOI: 10.1371/journal.pgen.1006744] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 05/04/2017] [Accepted: 04/05/2017] [Indexed: 11/18/2022] Open
Abstract
Degeneration and loss of lower motor neurons is the major pathological hallmark of spinal muscular atrophy (SMA), resulting from low levels of ubiquitously-expressed survival motor neuron (SMN) protein. One remarkable, yet unresolved, feature of SMA is that not all motor neurons are equally affected, with some populations displaying a robust resistance to the disease. Here, we demonstrate that selective vulnerability of distinct motor neuron pools arises from fundamental modifications to their basal molecular profiles. Comparative gene expression profiling of motor neurons innervating the extensor digitorum longus (disease-resistant), gastrocnemius (intermediate vulnerability), and tibialis anterior (vulnerable) muscles in mice revealed that disease susceptibility correlates strongly with a modified bioenergetic profile. Targeting of identified bioenergetic pathways by enhancing mitochondrial biogenesis rescued motor axon defects in SMA zebrafish. Moreover, targeting of a single bioenergetic protein, phosphoglycerate kinase 1 (Pgk1), was found to modulate motor neuron vulnerability in vivo. Knockdown of pgk1 alone was sufficient to partially mimic the SMA phenotype in wild-type zebrafish. Conversely, Pgk1 overexpression, or treatment with terazosin (an FDA-approved small molecule that binds and activates Pgk1), rescued motor axon phenotypes in SMA zebrafish. We conclude that global bioenergetics pathways can be therapeutically manipulated to ameliorate SMA motor neuron phenotypes in vivo.
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Affiliation(s)
- Penelope J. Boyd
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Wen-Yo Tu
- Sheffield Institute for Translation Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Hannah K. Shorrock
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Ewout J. N. Groen
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Roderick N. Carter
- University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Queens Medical Research Institute, Edinburgh, United Kingdom
| | - Rachael A. Powis
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Sophie R. Thomson
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Derek Thomson
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Laura C. Graham
- Division of Neurobiology, Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Anna A. L. Motyl
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Thomas M. Wishart
- Division of Neurobiology, Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - J. Robin Highley
- Sheffield Institute for Translation Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Nicholas M. Morton
- University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Queens Medical Research Institute, Edinburgh, United Kingdom
| | - Thomas Becker
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Neuroregeneration, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Catherina G. Becker
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Neuroregeneration, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Paul R. Heath
- Sheffield Institute for Translation Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Thomas H. Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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243
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Saifetiarova J, Liu X, Taylor AM, Li J, Bhat MA. Axonal domain disorganization in Caspr1 and Caspr2 mutant myelinated axons affects neuromuscular junction integrity, leading to muscle atrophy. J Neurosci Res 2017; 95:1373-1390. [PMID: 28370195 DOI: 10.1002/jnr.24052] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 02/14/2017] [Accepted: 02/24/2017] [Indexed: 12/19/2022]
Abstract
Bidirectional interactions between neurons and myelinating glial cells result in formation of axonal domains along myelinated fibers. Loss of axonal domains leads to detrimental consequences on nerve structure and function, resulting in reduced conductive properties and the diminished ability to reliably transmit signals to the targets they innervate. Thus, impairment of peripheral myelinated axons that project to the surface of muscle fibers and form neuromuscular junction (NMJ) synapses leads to muscle dysfunction. The goal of our studies was to determine how altered electrophysiological properties due to axonal domain disorganization lead to muscle pathology, which is relevant to a variety of peripheral neuropathies, demyelinating diseases, and neurodegenerative disorders. Using conventional Contactin-Associated Protein 1 (Caspr1) and Caspr2 single or double mutants with disrupted paranodal, juxtaparanodal, or both regions, respectively, in peripheral myelinated axons, we correlated defects in NMJ integrity and muscle pathology. Our data show that loss of axonal domains in Caspr1 and Caspr2 single and double mutants primarily alters distal myelinated fibers together with presynaptic terminals, eventually leading to NMJ denervation and reduction in postsynaptic endplate areas. Moreover, reduction in conductive properties of peripheral myelinated fibers together with NMJ disintegration leads to muscle atrophy in Caspr1 mutants or muscle fiber degeneration accompanied by mitochondrial dysfunction in Caspr1/Caspr2 double mutants. Together, our data indicate that proper organization of axonal domains in myelinated fibers is critical for optimal propagation of electrical signals, NMJ integrity, and muscle health, and provide insights into a wide range of pathologies that result in reduced nerve conduction leading to muscle atrophy. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Julia Saifetiarova
- Department of Cellular and Integrative Physiology, Center for Biomedical Neuroscience, School of Medicine, University of Texas Health Science Center, San Antonio, Texas
| | - Xi Liu
- Department of Cellular and Integrative Physiology, Center for Biomedical Neuroscience, School of Medicine, University of Texas Health Science Center, San Antonio, Texas.,Xiangya School of Medicine, Central South University, Changsha, China
| | - Anna M Taylor
- Department of Cellular and Integrative Physiology, Center for Biomedical Neuroscience, School of Medicine, University of Texas Health Science Center, San Antonio, Texas
| | - Jie Li
- Department of Cellular and Integrative Physiology, Center for Biomedical Neuroscience, School of Medicine, University of Texas Health Science Center, San Antonio, Texas
| | - Manzoor A Bhat
- Department of Cellular and Integrative Physiology, Center for Biomedical Neuroscience, School of Medicine, University of Texas Health Science Center, San Antonio, Texas
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244
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Abstract
Mitochondria are organelles that regulate essential eukaryotic functions including generating energy, sequestering excess calcium, and modulating cell survival. In order for neurons to thrive, mitochondria have to be continuously replenished by maintaining autophagic-lysosomal mediated degradation of mitochondria (mitophagy) and mitochondrial biogenesis. While a plethora of image- and biochemical-based techniques have been developed for measuring autophagy (macroautophagy) in eukaryotic cells, the molecular toolbox for quantifying and assessing mitophagy in neurons continues to evolve. Compared to proliferating cells, quantifying mitophagy in neurons poses a technical challenge given that mitochondria are predominantly present in neurites (axons and dendrites) and are highly dynamic. In this chapter, we provide a brief overview on mitophagy and provide a list of validated fluorescence- and biochemistry-based techniques used for assessing mitophagy in neuronal cells and primary neurons. Secondly, we provide comprehensive guidelines for interpreting steady-state levels of mitophagy and mitophagic flux in neurons using modern fluorescence- and biochemistry-based techniques. Finally, we provide a comprehensive list of common pitfalls to avoid when assessing mitophagy and offer practical solutions to overcome technical issues.
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245
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Magdalon J, Sánchez-Sánchez SM, Griesi-Oliveira K, Sertié AL. Dysfunctional mTORC1 Signaling: A Convergent Mechanism between Syndromic and Nonsyndromic Forms of Autism Spectrum Disorder? Int J Mol Sci 2017; 18:ijms18030659. [PMID: 28335463 PMCID: PMC5372671 DOI: 10.3390/ijms18030659] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 03/13/2017] [Accepted: 03/14/2017] [Indexed: 12/28/2022] Open
Abstract
Whereas autism spectrum disorder (ASD) exhibits striking heterogeneity in genetics and clinical presentation, dysfunction of mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway has been identified as a molecular feature common to several well-characterized syndromes with high prevalence of ASD. Additionally, recent findings have also implicated mTORC1 signaling abnormalities in a subset of nonsyndromic ASD, suggesting that defective mTORC1 pathway may be a potential converging mechanism in ASD pathology across different etiologies. However, the mechanistic evidence for a causal link between aberrant mTORC1 pathway activity and ASD neurobehavioral features varies depending on the ASD form involved. In this review, we first discuss six monogenic ASD-related syndromes, including both classical and potentially novel mTORopathies, highlighting their contribution to our understanding of the neurobiological mechanisms underlying ASD, and then we discuss existing evidence suggesting that aberrant mTORC1 signaling may also play a role in nonsyndromic ASD.
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Affiliation(s)
- Juliana Magdalon
- Hospital Israelita Albert Einstein, Centro de Pesquisa Experimental, São Paulo 05652-900, Brazil.
| | - Sandra M Sánchez-Sánchez
- Hospital Israelita Albert Einstein, Centro de Pesquisa Experimental, São Paulo 05652-900, Brazil.
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo 05508-090, Brazil.
| | - Karina Griesi-Oliveira
- Hospital Israelita Albert Einstein, Centro de Pesquisa Experimental, São Paulo 05652-900, Brazil.
| | - Andréa L Sertié
- Hospital Israelita Albert Einstein, Centro de Pesquisa Experimental, São Paulo 05652-900, Brazil.
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246
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Tsuyama T, Tsubouchi A, Usui T, Imamura H, Uemura T. Mitochondrial dysfunction induces dendritic loss via eIF2α phosphorylation. J Cell Biol 2017; 216:815-834. [PMID: 28209644 PMCID: PMC5346966 DOI: 10.1083/jcb.201604065] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 11/30/2016] [Accepted: 01/19/2017] [Indexed: 12/25/2022] Open
Abstract
Mitochondria are key contributors to the etiology of diseases associated with neuromuscular defects or neurodegeneration. How changes in cellular metabolism specifically impact neuronal intracellular processes and cause neuropathological events is still unclear. We here dissect the molecular mechanism by which mitochondrial dysfunction induced by Prel aberrant function mediates selective dendritic loss in Drosophila melanogaster class IV dendritic arborization neurons. Using in vivo ATP imaging, we found that neuronal cellular ATP levels during development are not correlated with the progression of dendritic loss. We searched for mitochondrial stress signaling pathways that induce dendritic loss and found that mitochondrial dysfunction is associated with increased eIF2α phosphorylation, which is sufficient to induce dendritic pathology in class IV arborization neurons. We also observed that eIF2α phosphorylation mediates dendritic loss when mitochondrial dysfunction results from other genetic perturbations. Furthermore, mitochondrial dysfunction induces translation repression in class IV neurons in an eIF2α phosphorylation-dependent manner, suggesting that differential translation attenuation among neuron subtypes is a determinant of preferential vulnerability.
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Affiliation(s)
- Taiichi Tsuyama
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Asako Tsubouchi
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Tadao Usui
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Hiromi Imamura
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Tadashi Uemura
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
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247
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Khalil B, Cabirol-Pol MJ, Miguel L, Whitworth AJ, Lecourtois M, Liévens JC. Enhancing Mitofusin/Marf ameliorates neuromuscular dysfunction in Drosophila models of TDP-43 proteinopathies. Neurobiol Aging 2017; 54:71-83. [PMID: 28324764 DOI: 10.1016/j.neurobiolaging.2017.02.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 02/20/2017] [Accepted: 02/22/2017] [Indexed: 12/14/2022]
Abstract
Transactive response DNA-binding protein 43 kDa (TDP-43) is considered a major pathological protein in amyotrophic lateral sclerosis and frontotemporal lobar degeneration. The precise mechanisms by which TDP-43 dysregulation leads to toxicity in neurons are not fully understood. Using TDP-43-expressing Drosophila, we examined whether mitochondrial dysfunction is a central determinant in TDP-43 pathogenesis. Expression of human wild-type TDP-43 in Drosophila neurons results in abnormally small mitochondria. The mitochondrial fragmentation is correlated with a specific decrease in the mRNA and protein levels of the Drosophila profusion gene mitofusin/marf. Importantly, overexpression of Marf ameliorates defects in spontaneous walking activity and startle-induced climbing response of TDP-43-expressing flies. Partial inactivation of the mitochondrial profission factor, dynamin-related protein 1, also mitigates TDP-43-induced locomotor deficits. Expression of TDP-43 impairs neuromuscular junction transmission upon repetitive stimulation of the giant fiber circuit that controls flight muscles, which is also ameliorated by Marf overexpression. We show here for the first time that enhancing the profusion gene mitofusin/marf is beneficial in an in vivo model of TDP-43 proteinopathies, serving as a potential therapeutic target.
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Affiliation(s)
- Bilal Khalil
- Aix-Marseille Université, CNRS, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille, UMR 7286, Marseille Cedex 15, France
| | - Marie-Jeanne Cabirol-Pol
- Aix-Marseille Université, CNRS, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille, UMR 7286, Marseille Cedex 15, France
| | - Laetitia Miguel
- Inserm, U1079, Rouen, France; IRIB Institute for Research and Innovation in Biomedicine, University of Rouen, Rouen, France
| | | | - Magalie Lecourtois
- Inserm, U1079, Rouen, France; IRIB Institute for Research and Innovation in Biomedicine, University of Rouen, Rouen, France
| | - Jean-Charles Liévens
- Aix-Marseille Université, CNRS, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille, UMR 7286, Marseille Cedex 15, France; MMDN, Université de Montpellier, EPHE, INSERM, U1198, Montpellier, France.
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248
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Todorova V, Blokland A. Mitochondria and Synaptic Plasticity in the Mature and Aging Nervous System. Curr Neuropharmacol 2017; 15:166-173. [PMID: 27075203 PMCID: PMC5327446 DOI: 10.2174/1570159x14666160414111821] [Citation(s) in RCA: 145] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 03/23/2016] [Accepted: 04/11/2016] [Indexed: 01/11/2023] Open
Abstract
Synaptic plasticity in the adult brain is believed to represent the cellular mechanisms of learning and memory. Mitochondria are involved in the regulation of the complex processes of synaptic plasticity. This paper reviews the current knowledge on the regulatory roles of mitochondria in the function and plasticity of synapses and the implications of mitochondrial dysfunctions in synaptic transmission. First, the importance of mitochondrial distribution and motility for maintenance and strengthening of dendritic spines, but also for new spines/synapses formation is presented. Secondly, the major mitochondrial functions as energy supplier and calcium buffer organelles are considered as possible explanation for their essential and regulatory roles in neuronal plasticity processes. Thirdly, the effects of synaptic potentiation on mitochondrial gene expression are discussed. And finally, the relation between age-related alterations in synaptic plasticity and mitochondrial dysfunctions is considered. It appears that memory loss and neurodegeneration during aging are related to mitochondrial (dys)function. Although, it is clear that mitochondria are essential for synaptic plasticity, further studies are indicated to scrutinize the intracellular and molecular processes that regulate the functions of mitochondria in synaptic plasticity.
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Affiliation(s)
- Vyara Todorova
- Institute II for Anatomy, Medical Faculty, University of Cologne, Cologne, Germany
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249
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Du J, Zhu M, Bao H, Li B, Dong Y, Xiao C, Zhang GY, Henter I, Rudorfer M, Vitiello B. The Role of Nutrients in Protecting Mitochondrial Function and Neurotransmitter Signaling: Implications for the Treatment of Depression, PTSD, and Suicidal Behaviors. Crit Rev Food Sci Nutr 2017; 56:2560-2578. [PMID: 25365455 DOI: 10.1080/10408398.2013.876960] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Numerous studies have linked severe stress to the development of major depressive disorder (MDD) and suicidal behaviors. Furthermore, recent preclinical studies from our laboratory and others have demonstrated that in rodents, chronic stress and the stress hormone cortisol cause oxidative damage to mitochondrial function and membrane lipids in the brain. Mitochondria play a key role in synaptic neurotransmitter signaling by providing adenosine triphosphate (ATP), mediating lipid and protein synthesis, buffering intracellular calcium, and regulating apoptotic and resilience pathways. Membrane lipids are similarly essential to central nervous system (CNS) function because cholesterol, polyunsaturated fatty acids, and sphingolipids form a lipid raft region, a special lipid region on the membrane that mediates neurotransmitter signaling through G-protein-coupled receptors and ion channels. Low serum cholesterol levels, low antioxidant capacity, and abnormal early morning cortisol levels are biomarkers consistently associated with both depression and suicidal behaviors. In this review, we summarize the manner in which nutrients can protect against oxidative damage to mitochondria and lipids in the neuronal circuits associated with cognitive and affective behaviors. These nutrients include ω3 fatty acids, antioxidants (vitamin C and zinc), members of the vitamin B family (Vitamin B12 and folic acid), and magnesium. Accumulating data have shown that these nutrients can enhance neurocognitive function, and may have therapeutic benefits for depression and suicidal behaviors. A growing body of studies suggests the intriguing possibility that regular consumption of these nutrients may help prevent the onset of mood disorders and suicidal behaviors in vulnerable individuals, or significantly augment the therapeutic effect of available antidepressants. These findings have important implications for the health of both military and civilian populations.
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Affiliation(s)
- Jing Du
- a School of Medicine, Yunnan University , Kunming , Yunnan , China.,c Laboratory of Molecular Pathophysiology, Intramural Research Program, NIMH, NIH , Bethesda , Maryland , USA
| | - Ming Zhu
- a School of Medicine, Yunnan University , Kunming , Yunnan , China
| | - Hongkun Bao
- a School of Medicine, Yunnan University , Kunming , Yunnan , China
| | - Bai Li
- a School of Medicine, Yunnan University , Kunming , Yunnan , China
| | - Yilong Dong
- a School of Medicine, Yunnan University , Kunming , Yunnan , China
| | - Chunjie Xiao
- a School of Medicine, Yunnan University , Kunming , Yunnan , China
| | - Grace Y Zhang
- c Laboratory of Molecular Pathophysiology, Intramural Research Program, NIMH, NIH , Bethesda , Maryland , USA
| | - Ioline Henter
- d Molecular Imaging Branch, Intramural Research Program, NIMH, NIH , Bethesda , Maryland , USA
| | - Matthew Rudorfer
- b Division of Service and Intervention Research, NIMH, NIH , Rockville , Maryland , USA
| | - Benedetto Vitiello
- b Division of Service and Intervention Research, NIMH, NIH , Rockville , Maryland , USA
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250
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Flippo KH, Strack S. Mitochondrial dynamics in neuronal injury, development and plasticity. J Cell Sci 2017; 130:671-681. [PMID: 28154157 DOI: 10.1242/jcs.171017] [Citation(s) in RCA: 166] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mitochondria fulfill numerous cellular functions including ATP production, Ca2+ buffering, neurotransmitter synthesis and degradation, ROS production and sequestration, apoptosis and intermediate metabolism. Mitochondrial dynamics, a collective term for the processes of mitochondrial fission, fusion and transport, governs mitochondrial function and localization within the cell. Correct balance of mitochondrial dynamics is especially important in neurons as mutations in fission and fusion enzymes cause peripheral neuropathies and impaired development of the nervous system in humans. Regulation of mitochondrial dynamics is partly accomplished through post-translational modification of mitochondrial fission and fusion enzymes, in turn influencing mitochondrial bioenergetics and transport. The importance of post-translational regulation is highlighted by numerous neurodegenerative disorders associated with post-translational modification of the mitochondrial fission enzyme Drp1. Not surprisingly, mitochondrial dynamics also play an important physiological role in the development of the nervous system and synaptic plasticity. Here, we highlight recent findings underlying the mechanisms and regulation of mitochondrial dynamics in relation to neurological disease, as well as the development and plasticity of the nervous system.
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Affiliation(s)
- Kyle H Flippo
- Department of Pharmacology, University of Iowa, Iowa City, USA
| | - Stefan Strack
- Department of Pharmacology, University of Iowa, Iowa City, USA
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