101
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Lees RM, Johnson JD, Ashby MC. Presynaptic Boutons That Contain Mitochondria Are More Stable. Front Synaptic Neurosci 2020; 11:37. [PMID: 31998110 PMCID: PMC6966497 DOI: 10.3389/fnsyn.2019.00037] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 12/18/2019] [Indexed: 01/04/2023] Open
Abstract
The addition and removal of presynaptic terminals reconfigures neuronal circuits of the mammalian neocortex, but little is known about how this presynaptic structural plasticity is controlled. Since mitochondria can regulate presynaptic function, we investigated whether the presence of axonal mitochondria relates to the structural plasticity of presynaptic boutons in mouse neocortex. We found that the overall density of axonal mitochondria did not appear to influence the loss and gain of boutons. However, positioning of mitochondria at individual presynaptic sites did relate to increased stability of those boutons. In line with this, synaptic localization of mitochondria increased as boutons aged and showed differing patterns of localization at en passant and terminaux boutons. These results suggest that mitochondria accumulate locally at boutons over time to increase bouton stability.
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Affiliation(s)
| | | | - Michael C. Ashby
- School of Physiology, Pharmacology, and Neuroscience, Faculty of Biomedical Sciences, University of Bristol, Bristol, United Kingdom
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102
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Clarke RA, Furlong TM, Eapen V. Tourette Syndrome Risk Genes Regulate Mitochondrial Dynamics, Structure, and Function. Front Psychiatry 2020; 11:556803. [PMID: 33776808 PMCID: PMC7987655 DOI: 10.3389/fpsyt.2020.556803] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 11/23/2020] [Indexed: 11/13/2022] Open
Abstract
Gilles de la Tourette syndrome (GTS) is a neurodevelopmental disorder characterized by motor and vocal tics with an estimated prevalence of 1% in children and adolescents. GTS has high rates of inheritance with many rare mutations identified. Apart from the role of the neurexin trans-synaptic connexus (NTSC) little has been confirmed regarding the molecular basis of GTS. The NTSC pathway regulates neuronal circuitry development, synaptic connectivity and neurotransmission. In this study we integrate GTS mutations into mitochondrial pathways that also regulate neuronal circuitry development, synaptic connectivity and neurotransmission. Many deleterious mutations in GTS occur in genes with complementary and consecutive roles in mitochondrial dynamics, structure and function (MDSF) pathways. These genes include those involved in mitochondrial transport (NDE1, DISC1, OPA1), mitochondrial fusion (OPA1), fission (ADCY2, DGKB, AMPK/PKA, RCAN1, PKC), mitochondrial metabolic and bio-energetic optimization (IMMP2L, MPV17, MRPL3, MRPL44). This study is the first to develop and describe an integrated mitochondrial pathway in the pathogenesis of GTS. The evidence from this study and our earlier modeling of GTS molecular pathways provides compounding support for a GTS deficit in mitochondrial supply affecting neurotransmission.
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Affiliation(s)
- Raymond A Clarke
- School of Psychiatry, University of New South Wales, Sydney, NSW, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia
| | - Teri M Furlong
- School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Valsamma Eapen
- School of Psychiatry, University of New South Wales, Sydney, NSW, Australia.,Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia.,South West Sydney Local Health District, Liverpool Hospital, Liverpool, NSW, Australia
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103
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Kim Y, Zheng X, Ansari Z, Bunnell MC, Herdy JR, Traxler L, Lee H, Paquola ACM, Blithikioti C, Ku M, Schlachetzki JCM, Winkler J, Edenhofer F, Glass CK, Paucar AA, Jaeger BN, Pham S, Boyer L, Campbell BC, Hunter T, Mertens J, Gage FH. Mitochondrial Aging Defects Emerge in Directly Reprogrammed Human Neurons due to Their Metabolic Profile. Cell Rep 2019; 23:2550-2558. [PMID: 29847787 DOI: 10.1016/j.celrep.2018.04.105] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 01/19/2018] [Accepted: 04/19/2018] [Indexed: 12/11/2022] Open
Abstract
Mitochondria are a major target for aging and are instrumental in the age-dependent deterioration of the human brain, but studying mitochondria in aging human neurons has been challenging. Direct fibroblast-to-induced neuron (iN) conversion yields functional neurons that retain important signs of aging, in contrast to iPSC differentiation. Here, we analyzed mitochondrial features in iNs from individuals of different ages. iNs from old donors display decreased oxidative phosphorylation (OXPHOS)-related gene expression, impaired axonal mitochondrial morphologies, lower mitochondrial membrane potentials, reduced energy production, and increased oxidized proteins levels. In contrast, the fibroblasts from which iNs were generated show only mild age-dependent changes, consistent with a metabolic shift from glycolysis-dependent fibroblasts to OXPHOS-dependent iNs. Indeed, OXPHOS-induced old fibroblasts show increased mitochondrial aging features similar to iNs. Our data indicate that iNs are a valuable tool for studying mitochondrial aging and support a bioenergetic explanation for the high susceptibility of the brain to aging.
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Affiliation(s)
- Yongsung Kim
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Xinde Zheng
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Zoya Ansari
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Mark C Bunnell
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Joseph R Herdy
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Larissa Traxler
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA; Institute of Molecular Biology, Leopold-Franzens-University Innsbruck, Technikerstraβe 25, 6020 Innsbruck, Austria
| | - Hyungjun Lee
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Apua C M Paquola
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA; Lieber Institute for Brain Development, 855 North Wolfe Street, Suite 300, Baltimore, MD 21205, USA
| | - Chrysanthi Blithikioti
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Manching Ku
- Next Generation Sequencing Core, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA; Clinic for Pediatric Hematology and Oncology, Center for Pediatrics and Adolescent Medicine, University of Freiburg Medical Center, Mathildenstraβe 1, 79106 Freiburg im Breisgau, Germany
| | - Johannes C M Schlachetzki
- Department of Molecular Neurology, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany; Department of Cellular and Molecular Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0651, USA
| | - Jürgen Winkler
- Department of Molecular Neurology, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Frank Edenhofer
- Institute of Molecular Biology, Leopold-Franzens-University Innsbruck, Technikerstraβe 25, 6020 Innsbruck, Austria
| | - Christopher K Glass
- Department of Cellular and Molecular Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0651, USA
| | - Andres A Paucar
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Baptiste N Jaeger
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Son Pham
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Leah Boyer
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Benjamin C Campbell
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Tony Hunter
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Jerome Mertens
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA; Institute of Molecular Biology, Leopold-Franzens-University Innsbruck, Technikerstraβe 25, 6020 Innsbruck, Austria.
| | - Fred H Gage
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
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104
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Puertas-Frías G, Del Arco A, Pardo B, Satrústegui J, Contreras L. Mitochondrial movement in Aralar/Slc25a12/AGC1 deficient cortical neurons. Neurochem Int 2019; 131:104541. [PMID: 31472174 DOI: 10.1016/j.neuint.2019.104541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 07/25/2019] [Accepted: 08/28/2019] [Indexed: 12/12/2022]
Abstract
The elevated energy demands in the brain are fulfilled mainly by glucose catabolism. In highly polarized neurons, about 10-50% of mitochondria are transported along microtubules using mitochondrial-born ATP to locations with high energy requirements. In this report, we have investigated the impact of Aralar deficiency on mitochondrial transport in cultured cortical neurons. Aralar/slc25a12/AGC1 is the neuronal isoform of the aspartate-glutamate mitochondrial carrier, a component of the malate-aspartate shuttle (MAS) which plays an important role in redox balance, which is essential to maintain glycolytic pyruvate supply to neuronal mitochondria. Using live imaging microscopy we observed that the lack of Aralar does not affect the number of moving mitochondria nor the Ca2+-induced stop, the only difference being a 10% increase in mitochondrial velocity in Aralar deficient neurons. Therefore, we evaluated the possible fuels used in each case by studying the relative contribution of oxidative phosphorylation and glycolysis to mitochondrial movement using specific inhibitors. We found that the ATP synthase inhibitor oligomycin caused a smaller inhibition of mitochondrial movement in Aralar-KO than control neurons, whereas the glycolysis inhibitor iodoacetate had similar effects in neurons from both genotypes. In line with these findings, the decrease in cytosolic ATP/ADP ratio caused by oligomycin was more pronounced in control than in Aralar-KO neurons, but no differences were observed with iodoacetate. Oligomycin effect was reverted by aralar re-expression in knock out cultures. As mitochondrial movement is not reduced in Aralar-KO neurons, these results suggest that these neurons may use an additional pathway for mitochondria movement and ATP/ADP ratio maintenance.
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Affiliation(s)
- Guillermo Puertas-Frías
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa UAM-CSIC, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049, Madrid, Spain
| | - Araceli Del Arco
- Facultad de Ciencias Ambientales y Bioquímica, Centro Regional de Investigaciones Biomédicas, Universidad de Castilla La Mancha, 45071, Toledo, Spain; Instituto de Investigación Sanitaria Fundación Jiménez Díaz (IISFJD), 28049, Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28049, Madrid, Spain
| | - Beatriz Pardo
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa UAM-CSIC, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049, Madrid, Spain; Instituto de Investigación Sanitaria Fundación Jiménez Díaz (IISFJD), 28049, Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28049, Madrid, Spain
| | - Jorgina Satrústegui
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa UAM-CSIC, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049, Madrid, Spain; Instituto de Investigación Sanitaria Fundación Jiménez Díaz (IISFJD), 28049, Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28049, Madrid, Spain
| | - Laura Contreras
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa UAM-CSIC, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049, Madrid, Spain; Instituto de Investigación Sanitaria Fundación Jiménez Díaz (IISFJD), 28049, Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28049, Madrid, Spain.
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105
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Chamberlain KA, Sheng ZH. Mechanisms for the maintenance and regulation of axonal energy supply. J Neurosci Res 2019; 97:897-913. [PMID: 30883896 PMCID: PMC6565461 DOI: 10.1002/jnr.24411] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 02/04/2019] [Accepted: 02/18/2019] [Indexed: 12/25/2022]
Abstract
The unique polarization and high-energy demand of neurons necessitates specialized mechanisms to maintain energy homeostasis throughout the cell, particularly in the distal axon. Mitochondria play a key role in meeting axonal energy demand by generating adenosine triphosphate through oxidative phosphorylation. Recent evidence demonstrates how axonal mitochondrial trafficking and anchoring are coordinated to sense and respond to altered energy requirements. If and when these mechanisms are impacted in pathological conditions, such as injury and neurodegenerative disease, is an emerging research frontier. Recent evidence also suggests that axonal energy demand may be supplemented by local glial cells, including astrocytes and oligodendrocytes. In this review, we provide an updated discussion of how oxidative phosphorylation, aerobic glycolysis, and oligodendrocyte-derived metabolic support contribute to the maintenance of axonal energy homeostasis.
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Affiliation(s)
- Kelly Anne Chamberlain
- 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, Maryland 20892-3706, USA
| | - 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, Maryland 20892-3706, USA
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106
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Devine MJ, Kittler JT. Mitochondria at the neuronal presynapse in health and disease. Nat Rev Neurosci 2019; 19:63-80. [PMID: 29348666 DOI: 10.1038/nrn.2017.170] [Citation(s) in RCA: 344] [Impact Index Per Article: 68.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Synapses enable neurons to communicate with each other and are therefore a prerequisite for normal brain function. Presynaptically, this communication requires energy and generates large fluctuations in calcium concentrations. Mitochondria are optimized for supplying energy and buffering calcium, and they are actively recruited to presynapses. However, not all presynapses contain mitochondria; thus, how might synapses with and without mitochondria differ? Mitochondria are also increasingly recognized to serve additional functions at the presynapse. Here, we discuss the importance of presynaptic mitochondria in maintaining neuronal homeostasis and how dysfunctional presynaptic mitochondria might contribute to the development of disease.
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Affiliation(s)
- Michael J Devine
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Josef T Kittler
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
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107
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Cao J, Zhong MB, Toro CA, Zhang L, Cai D. Endo-lysosomal pathway and ubiquitin-proteasome system dysfunction in Alzheimer's disease pathogenesis. Neurosci Lett 2019; 703:68-78. [PMID: 30890471 PMCID: PMC6760990 DOI: 10.1016/j.neulet.2019.03.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 02/19/2019] [Accepted: 03/11/2019] [Indexed: 01/04/2023]
Abstract
Several lines of evidence have shown that defects in the endo-lysosomal autophagy degradation pathway and the ubiquitin-proteasome system play a role in Alzheimer's Disease (AD) pathogenesis and pathophysiology. Early pathological changes, such as marked enlargement of endosomal compartments, gradual accumulation of autophagic vacuoles (AVs) and lysosome dyshomeostasis, are well-recognized in AD. In addition to these pathological indicators, many genetic variants of key regulators in the endo-lysosomal autophagy networks and the ubiquitin-proteasome system have been found to be associated with AD. Furthermore, altered expression levels of key proteins in these pathways have been found in AD human brain tissues, primary cells and AD mouse models. In this review, we discuss potential disease mechanisms underlying the dysregulation of protein homeostasis governing systems. While the importance of two major protein degradation pathways in AD pathogenesis has been highlighted, targeted therapy at key components of these pathways has great potential in developing novel therapeutic interventions for AD. Future investigations are needed to define molecular mechanisms by which these complex regulatory systems become malfunctional at specific stages of AD development and progression, which will facilitate future development of novel therapeutic interventions. It is also critical to investigate all key components of the protein degradation pathways, both upstream and downstream, to improve our abilities to manipulate transport pathways with higher efficacy and less side effects.
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Affiliation(s)
- Jiqing Cao
- Research and Development, James J Peters VA Medical Center, Bronx, NY 10468, United States; Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; The Central Hospital of The Hua Zhong University of Science and Technology, Wuhan, China.
| | - Margaret B Zhong
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; Barnard College of Columbia University, New York, NY 10027, United States.
| | - Carlos A Toro
- Research and Development, James J Peters VA Medical Center, Bronx, NY 10468, United States; National Center for the Medical Consequences of Spinal Cord Injury, James J Peters VA Medical Center, Bronx, NY 10468, United States; Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
| | - Larry Zhang
- Research and Development, James J Peters VA Medical Center, Bronx, NY 10468, United States; Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
| | - Dongming Cai
- Research and Development, James J Peters VA Medical Center, Bronx, NY 10468, United States; Neurology Section, James J Peters VA Medical Center, Bronx, NY 10468, United States; Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States; The Central Hospital of The Hua Zhong University of Science and Technology, Wuhan, China.
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108
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Padamsey Z, Foster WJ, Emptage NJ. Intracellular Ca 2+ Release and Synaptic Plasticity: A Tale of Many Stores. Neuroscientist 2019; 25:208-226. [PMID: 30014771 DOI: 10.1177/1073858418785334] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ca2+ is an essential trigger for most forms of synaptic plasticity. Ca2+ signaling occurs not only by Ca2+ entry via plasma membrane channels but also via Ca2+ signals generated by intracellular organelles. These organelles, by dynamically regulating the spatial and temporal extent of Ca2+ elevations within neurons, play a pivotal role in determining the downstream consequences of neural signaling on synaptic function. Here, we review the role of three major intracellular stores: the endoplasmic reticulum, mitochondria, and acidic Ca2+ stores, such as lysosomes, in neuronal Ca2+ signaling and plasticity. We provide a comprehensive account of how Ca2+ release from these stores regulates short- and long-term plasticity at the pre- and postsynaptic terminals of central synapses.
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Affiliation(s)
- Zahid Padamsey
- 1 Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, 15 George Square, Edinburgh, UK
| | - William J Foster
- 2 Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, Oxfordshire, UK
| | - Nigel J Emptage
- 2 Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, Oxfordshire, UK
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109
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Reichart G, Mayer J, Zehm C, Kirschstein T, Tokay T, Lange F, Baltrusch S, Tiedge M, Fuellen G, Ibrahim S, Köhling R. Mitochondrial complex IV mutation increases reactive oxygen species production and reduces lifespan in aged mice. Acta Physiol (Oxf) 2019; 225:e13214. [PMID: 30376218 DOI: 10.1111/apha.13214] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 10/18/2018] [Accepted: 10/24/2018] [Indexed: 12/17/2022]
Abstract
AIM Mitochondrial DNA (mtDNA) mutations can negatively influence lifespan and organ function. More than 250 pathogenic mtDNA mutations are known, often involving neurological symptoms. Major neurodegenerative diseases share key etiopathogenetic components ie mtDNA mutations, mitochondrial dysfunction and oxidative stress. METHODS Here, we characterized a conplastic mouse strain (C57BL/6 J-mtNOD) carrying an electron transport chain complex IV mutation that leads to an altered cytochrome c oxidase subunit III. Since this mouse also harbours adenine insertions in the mitochondrial tRNA for arginine, we chose the C57BL/6 J-mtMRL as control strain which also carries a heteroplasmic stretch of adenine repetitions in this tRNA isoform. RESULTS Using MitoSOX fluorescence, we observed an elevated mitochondrial superoxide production and a reduced gene expression of superoxide dismutase 2 in the 24-month-old mtNOD mouse as compared to control. Together with the decreased expression of the fission-relevant gene Fis1, these data confirmed that the ageing mtNOD mouse had a mitochondrial dysfunctional phenotype. On the functional level, we could not detect significant differences in synaptic long-term potentiation, but found a markedly poor physical constitution to perform the Morris water maze task at the age of 24 months. Moreover, the median lifespan of mtNOD mice was significantly shorter than of control animals. CONCLUSION Our findings demonstrate that a complex IV mutation leads to mitochondrial dysfunction that translates into survival.
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Affiliation(s)
- Gesine Reichart
- Oscar Langendorff Institute of Physiology Rostock University Medical Center Rostock Germany
| | - Johannes Mayer
- Oscar Langendorff Institute of Physiology Rostock University Medical Center Rostock Germany
| | - Cindy Zehm
- Institute of Medical Biochemistry and Molecular Biology Rostock University Medical Center Rostock Germany
| | - Timo Kirschstein
- Oscar Langendorff Institute of Physiology Rostock University Medical Center Rostock Germany
| | - Tursonjan Tokay
- Oscar Langendorff Institute of Physiology Rostock University Medical Center Rostock Germany
- Center for Life Sciences Nazarbayev University Astana Kazakhstan
| | - Falko Lange
- Oscar Langendorff Institute of Physiology Rostock University Medical Center Rostock Germany
| | - Simone Baltrusch
- Institute of Medical Biochemistry and Molecular Biology Rostock University Medical Center Rostock Germany
| | - Markus Tiedge
- Institute of Medical Biochemistry and Molecular Biology Rostock University Medical Center Rostock Germany
| | - Georg Fuellen
- Institute for Biostatistics and Informatics in Medicine and Ageing Research Rostock Germany
- Interdisciplinary Faculty University of Rostock Rostock Germany
| | - Saleh Ibrahim
- Department of Dermatology Lübeck University Medical Center Lübeck Germany
| | - Rüdiger Köhling
- Oscar Langendorff Institute of Physiology Rostock University Medical Center Rostock Germany
- Interdisciplinary Faculty University of Rostock Rostock Germany
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110
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Musazzi L, Sala N, Tornese P, Gallivanone F, Belloli S, Conte A, Di Grigoli G, Chen F, Ikinci A, Treccani G, Bazzini C, Castiglioni I, Nyengaard JR, Wegener G, Moresco RM, Popoli M. Acute Inescapable Stress Rapidly Increases Synaptic Energy Metabolism in Prefrontal Cortex and Alters Working Memory Performance. Cereb Cortex 2019; 29:4948-4957. [DOI: 10.1093/cercor/bhz034] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 01/15/2019] [Accepted: 02/08/2019] [Indexed: 12/19/2022] Open
Abstract
Abstract
Brain energy metabolism actively regulates synaptic transmission and activity. We have previously shown that acute footshock (FS)-stress induces fast and long-lasting functional and morphological changes at excitatory synapses in prefrontal cortex (PFC). Here, we asked whether FS-stress increased energy metabolism in PFC, and modified related cognitive functions. Using positron emission tomography (PET), we found that FS-stress induced a redistribution of glucose metabolism in the brain, with relative decrease of [18F]FDG uptake in ventro-caudal regions and increase in dorso-rostral ones. Absolute [18F]FDG uptake was inversely correlated with serum corticosterone. Increased specific hexokinase activity was also measured in purified PFC synaptosomes (but not in total extract) of FS-stressed rats, which positively correlated with 2-Deoxy [3H] glucose uptake by synaptosomes. In line with increased synaptic energy demand, using an electron microscopy-based stereological approach, we found that acute stress induced a redistribution of mitochondria at excitatory synapses, together with an increase in their volume. The fast functional and metabolic activation of PFC induced by acute stress, was accompanied by rapid and sustained alterations of working memory performance in delayed response to T-maze test. Taken together, the present data suggest that acute stress increases energy consumption at PFC synaptic terminals and alters working memory.
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Affiliation(s)
- Laura Musazzi
- Laboratory of Neuropsychopharmacology and Functional Neurogenomics, Dipartimento di Scienze Farmacologiche e Biomolecolari and CEND, Università degli Studi di Milano, Milano, Italy
| | - Nathalie Sala
- Laboratory of Neuropsychopharmacology and Functional Neurogenomics, Dipartimento di Scienze Farmacologiche e Biomolecolari and CEND, Università degli Studi di Milano, Milano, Italy
| | - Paolo Tornese
- Laboratory of Neuropsychopharmacology and Functional Neurogenomics, Dipartimento di Scienze Farmacologiche e Biomolecolari and CEND, Università degli Studi di Milano, Milano, Italy
| | - Francesca Gallivanone
- Institute of Molecular Bioimaging and Physiology (IBFM), Milan Center for Neuroscience (NeuroMi) CNR, Segrate, Italy
| | - Sara Belloli
- Institute of Molecular Bioimaging and Physiology (IBFM), Milan Center for Neuroscience (NeuroMi) CNR, Segrate, Italy
| | - Alessandra Conte
- Laboratory of Neuropsychopharmacology and Functional Neurogenomics, Dipartimento di Scienze Farmacologiche e Biomolecolari and CEND, Università degli Studi di Milano, Milano, Italy
| | - Giuseppe Di Grigoli
- Institute of Molecular Bioimaging and Physiology (IBFM), Milan Center for Neuroscience (NeuroMi) CNR, Segrate, Italy
| | - Fengua Chen
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Risskov, Denmark
| | - Ayşe Ikinci
- Department of Clinical Medicine, Core Centre for Molecular Morphology, Section for Stereology and Microscopy, Aarhus University Hospital, Aarhus C, Denmark
| | - Giulia Treccani
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Risskov, Denmark
| | - Chiara Bazzini
- Laboratory of Neuropsychopharmacology and Functional Neurogenomics, Dipartimento di Scienze Farmacologiche e Biomolecolari and CEND, Università degli Studi di Milano, Milano, Italy
| | - Isabella Castiglioni
- Institute of Molecular Bioimaging and Physiology (IBFM), Milan Center for Neuroscience (NeuroMi) CNR, Segrate, Italy
| | - Jens R Nyengaard
- Department of Clinical Medicine, Core Centre for Molecular Morphology, Section for Stereology and Microscopy, Aarhus University Hospital, Aarhus C, Denmark
| | - Gregers Wegener
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Risskov, Denmark
| | - Rosa M Moresco
- Nuclear Medicine Department, IRCCS San Raffaele Scientific Institute, Milan, Italy
- Department of Medicine and Surgery, University of Milan Bicocca, Monza, Italy
| | - Maurizio Popoli
- Laboratory of Neuropsychopharmacology and Functional Neurogenomics, Dipartimento di Scienze Farmacologiche e Biomolecolari and CEND, Università degli Studi di Milano, Milano, Italy
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111
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Petersen MH, Willert CW, Andersen JV, Waagepetersen HS, Skotte NH, Nørremølle A. Functional Differences between Synaptic Mitochondria from the Striatum and the Cerebral Cortex. Neuroscience 2019; 406:432-443. [PMID: 30876983 DOI: 10.1016/j.neuroscience.2019.02.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 02/08/2019] [Accepted: 02/28/2019] [Indexed: 12/16/2022]
Abstract
Mitochondrial dysfunction has been shown to play a major role in neurodegenerative disorders such as Huntington's disease, Alzheimer's disease and Parkinson's disease. In these and other neurodegenerative disorders, disruption of synaptic connectivity and impaired neuronal signaling are among the early signs. When looking for potential causes of neurodegeneration, specific attention is drawn to the function of synaptic mitochondria, as the energy supply from mitochondria is crucial for normal synaptic function. Mitochondrial heterogeneity between synaptic and non-synaptic mitochondria has been described, but very little is known about possible differences between synaptic mitochondria from different brain regions. The striatum and the cerebral cortex are often affected in neurodegenerative disorders. In this study we therefore used isolated nerve terminals (synaptosomes) from female mice, striatum and cerebral cortex, to investigate differences in synaptic mitochondrial function between these two brain regions. We analyzed mitochondrial mass, citrate synthase activity, general metabolic activity and mitochondrial respiration in resting as well as veratridine-activated synaptosomes using glucose and/or pyruvate as substrate. We found higher mitochondrial oxygen consumption rate in both resting and activated cortical synaptosomes compared to striatal synaptosomes, especially when using pyruvate as a substrate. The higher oxygen consumption rate was not caused by differences in mitochondrial content, but instead corresponded with a higher proton leak in the cortical synaptic mitochondria compared to the striatal synaptic mitochondria. Our results show that the synaptic mitochondria of the striatum and cortex differently regulate respiration both in response to activation and variations in substrate conditions.
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Affiliation(s)
- Maria Hvidberg Petersen
- Department of Cellular and Molecular Medicine, University of Copenhagen, 2200 Copenhagen N, Denmark
| | | | - Jens Velde Andersen
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen Ø, Denmark
| | | | - Niels Henning Skotte
- Proteomics Program, The Novo Nordisk Foundation Centre for Protein Research, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Anne Nørremølle
- Department of Cellular and Molecular Medicine, University of Copenhagen, 2200 Copenhagen N, Denmark.
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112
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Rossi MJ, Pekkurnaz G. Powerhouse of the mind: mitochondrial plasticity at the synapse. Curr Opin Neurobiol 2019; 57:149-155. [PMID: 30875521 DOI: 10.1016/j.conb.2019.02.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 02/05/2019] [Indexed: 12/16/2022]
Abstract
Neurons are highly polarized cells with extraordinary energy demands, which are mainly fulfilled by mitochondria. In response to altered neuronal energy state, mitochondria adapt to enable energy homeostasis and nervous system function. This adaptation, also called mitochondrial plasticity, can be observed as alterations in the form, function and position. The primary site of energy consumption in neurons is localized at the synapse, where mitochondria are critical for both pre- and postsynaptic functions. In this review, we will discuss molecular mechanisms regulating mitochondrial plasticity at the synapse and how they contribute to information processing within neurons.
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Affiliation(s)
- Meghan J Rossi
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States
| | - Gulcin Pekkurnaz
- Neurobiology Section, Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States.
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113
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Dysfunctional Mitochondrial Bioenergetics and Synaptic Degeneration in Alzheimer Disease. Int Neurourol J 2019; 23:S5-10. [PMID: 30832462 PMCID: PMC6433209 DOI: 10.5213/inj.1938036.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 02/15/2019] [Indexed: 12/21/2022] Open
Abstract
Synapses are sites of high energy demand which are dependent on high levels of mitochondrial derived adenosine triphosphate. Mitochondria within synaptic structures are key for maintenance of functional neurotransmission and this critical biological process is modulated by energy metabolism, mitochondrial distribution, mitochondrial trafficking, and cellular synaptic calcium flux. Synapse loss is presumed to be an early yet progressive pathological event in Alzheimer disease (AD), resulting in impaired cognitive function and memory loss which is particularly prevalent at later stages of disease. Supporting evidence from AD patients and animal models suggests that pathological mitochondrial dynamics indeed occurs early and is highly associated with synaptic lesions and degeneration in AD neurons. This review comprehensively highlights recent findings that describe how synaptic mitochondria pathology involves dysfunctional trafficking of this organelle, to maladaptive epigenetic contributions affecting mitochondrial function in AD. We further discuss how these negative, dynamic alterations impact synaptic function associated with AD. Finally, this review explores how antioxidant therapeutic approaches targeting mitochondria in AD can further clinical research and basic science investigations to advance our in-depth understanding of the pathogenesis of AD.
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114
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Abstract
Glucose is the long-established, obligatory fuel for brain that fulfills many critical functions, including ATP production, oxidative stress management, and synthesis of neurotransmitters, neuromodulators, and structural components. Neuronal glucose oxidation exceeds that in astrocytes, but both rates increase in direct proportion to excitatory neurotransmission; signaling and metabolism are closely coupled at the local level. Exact details of neuron-astrocyte glutamate-glutamine cycling remain to be established, and the specific roles of glucose and lactate in the cellular energetics of these processes are debated. Glycolysis is preferentially upregulated during brain activation even though oxygen availability is sufficient (aerobic glycolysis). Three major pathways, glycolysis, pentose phosphate shunt, and glycogen turnover, contribute to utilization of glucose in excess of oxygen, and adrenergic regulation of aerobic glycolysis draws attention to astrocytic metabolism, particularly glycogen turnover, which has a high impact on the oxygen-carbohydrate mismatch. Aerobic glycolysis is proposed to be predominant in young children and specific brain regions, but re-evaluation of data is necessary. Shuttling of glucose- and glycogen-derived lactate from astrocytes to neurons during activation, neurotransmission, and memory consolidation are controversial topics for which alternative mechanisms are proposed. Nutritional therapy and vagus nerve stimulation are translational bridges from metabolism to clinical treatment of diverse brain disorders.
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Affiliation(s)
- Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences , Little Rock, Arkansas ; and Department of Cell Biology and Physiology, University of New Mexico , Albuquerque, New Mexico
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115
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Sui Y, Nguyen HB, Thai TQ, Ikenaka K, Ohno N. Mitochondrial Dynamics in Physiology and Pathology of Myelinated Axons. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1190:145-163. [PMID: 31760643 DOI: 10.1007/978-981-32-9636-7_10] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mitochondria play essential roles in neurons and abnormal functions of mitochondria have been implicated in neurological disorders including myelin diseases. Since mitochondrial functions are regulated and maintained by their dynamic behavior involving localization, transport, and fusion/fission, modulation of mitochondrial dynamics would be involved in physiology and pathology of myelinated axons. In fact, the integration of multimodal imaging in vivo and in vitro revealed that mitochondrial localization and transport are differentially regulated in nodal and internodal regions in response to the changes of metabolic demand in myelinated axons. In addition, the mitochondrial behavior in axons is modulated as adaptive responses to demyelination irrespective of the cause of myelin loss, and the behavioral modulation is partly through interactions with cytoskeletons and closely associated with the pathophysiology of demyelinating diseases. Furthermore, the behavior and functions of axonal mitochondria are modulated in congenital myelin disorders involving impaired interactions between axons and myelin-forming cells, and, together with the inflammatory environment, implicated in axonal degeneration and disease phenotypes. Further studies on the regulatory mechanisms of the mitochondrial dynamics in myelinated axons would provide deeper insights into axo-glial interactions mediated through myelin ensheathment, and effective manipulations of the dynamics may lead to novel therapeutic strategies protecting axonal and neuronal functions and survival in primary diseases of myelin.
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Affiliation(s)
- Yang Sui
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Aichi, Japan.,Departments of Anatomy and Structural Biology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Yamanashi, Japan
| | - Huy Bang Nguyen
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Aichi, Japan.,Departments of Anatomy and Structural Biology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Yamanashi, Japan
| | - Truc Quynh Thai
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Aichi, Japan.,Departments of Anatomy and Structural Biology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Yamanashi, Japan
| | - Kazuhiro Ikenaka
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
| | - Nobuhiko Ohno
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Aichi, Japan. .,Department of Anatomy, Division of Histology and Cell Biology, Jichi Medical University, School of Medicine, Shimotsuke, Japan.
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116
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Kang JJ, Guo B, Liang WH, Lam CS, Wu SX, Huang XF, Wong-Riley MTT, Fung ML, Liu YY. Daily acute intermittent hypoxia induced dynamic changes in dendritic mitochondrial ultrastructure and cytochrome oxidase activity in the pre-Bötzinger complex of rats. Exp Neurol 2018; 313:124-134. [PMID: 30586594 DOI: 10.1016/j.expneurol.2018.12.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 12/18/2018] [Indexed: 12/29/2022]
Abstract
Mitochondria, as primary energy generators and Ca2+ biosensor, are dynamically coupled to neuronal activities, and thus play a role in neuroplasticity. Here we report that respiratory neuroplasticity induced by daily acute intermittent hypoxia (dAIH) evoked adaptive changes in the ultrastructure and postsynaptic distribution of mitochondria in the pre-Bötzinger complex (pre-BötC). The metabolic marker of neuronal activity, cytochrome c oxidase (CO), and dendritic mitochondria were examined in pre-BötC neurons of adult Sprague-Dawley rats preconditioned with dAIH, which is known to induce long-term facilitation (LTF) in respiratory neural activities. We performed neurokinin 1 receptor (NK1R) pre-embedding immunocytochemistry to define pre-BötC neurons, in combination with CO histochemistry, to depict ultrastructural alterations and CO activity in dendritic mitochondria. We found that the dAIH challenge significantly increased CO activity in pre-BötC neurons. Darkly CO-reactive mitochondria at postsynaptic sites in the dAIH group were much more prevalent than those in the normoxic control. In addition, the length and area of mitochondria were significantly increased in the dAIH group, implying a larger surface area of cristae for ATP generation. There was a fine, structural remodeling, notably enlarged and branching mitochondria or tapered mitochondria extending into dendritic spines. Mitochondrial cristae were mainly in parallel-lamellar arrangement, indicating a high efficiency of energy generation. Moreover, flocculent or filament-like elements were noted between the mitochondria and the postsynaptic membrane. These morphological evidences, together with increased CO activity, demonstrate that dendritic mitochondria in the pre-BötC responded dynamically to respiratory plasticity. Hence, plastic neuronal changes are closely coupled to active mitochondrial bioenergetics, leading to enhanced energy production and Ca2+ buffering that may drive the LTF expression.
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Affiliation(s)
- Jun-Jun Kang
- Department of Neurobiology, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Baolin Guo
- Department of Neurobiology, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Wei-Hua Liang
- Department of Pathology and Pathophysiology, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Chun-Sing Lam
- School of Biomedical Sciences, The University of Hong Kong, PR China
| | - Sheng-Xi Wu
- Department of Neurobiology, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Xiao-Feng Huang
- Department of Pathology and Pathophysiology, The Fourth Military Medical University, Xi'an 710032, PR China
| | - Margaret T T Wong-Riley
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Man-Lung Fung
- School of Biomedical Sciences, The University of Hong Kong, PR China.
| | - Ying-Ying Liu
- Department of Neurobiology, The Fourth Military Medical University, Xi'an 710032, PR China.
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117
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Region-specific depletion of synaptic mitochondria in the brains of patients with Alzheimer's disease. Acta Neuropathol 2018; 136:747-757. [PMID: 30191401 PMCID: PMC6208730 DOI: 10.1007/s00401-018-1903-2] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 08/22/2018] [Accepted: 08/22/2018] [Indexed: 01/04/2023]
Abstract
Of all of the neuropathological changes observed in Alzheimer’s disease (AD), the loss of synapses correlates most strongly with cognitive decline. The precise mechanisms of synapse degeneration in AD remain unclear, although strong evidence indicates that pathological forms of both amyloid beta and tau contribute to synaptic dysfunction and loss. Synaptic mitochondria play a potentially important role in synapse degeneration in AD. Many studies in model systems indicate that amyloid beta and tau both impair mitochondrial function and impair transport of mitochondria to synapses. To date, much less is known about whether synaptic mitochondria are affected in human AD brain. Here, we used transmission electron microscopy to examine synapses and synaptic mitochondria in two cortical regions (BA41/42 and BA46) from eight AD and nine control cases. In this study, we observed 3000 synapses and find region-specific differences in synaptic mitochondria in AD cases compared to controls. In BA41/42, we observe a fourfold reduction in the proportion of presynaptic terminals that contain multiple mitochondria profiles in AD. We also observe ultrastructural changes including abnormal mitochondrial morphology, the presence of multivesicular bodies in synapses, and reduced synapse apposition length near plaques in AD. Together, our data show region-specific changes in synaptic mitochondria in AD and support the idea that the transport of mitochondria to presynaptic terminals or synaptic mitochondrial dynamics may be altered in AD.
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118
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Fischer TD, Dash PK, Liu J, Waxham MN. Morphology of mitochondria in spatially restricted axons revealed by cryo-electron tomography. PLoS Biol 2018; 16:e2006169. [PMID: 30222729 PMCID: PMC6160218 DOI: 10.1371/journal.pbio.2006169] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 09/27/2018] [Accepted: 09/05/2018] [Indexed: 11/25/2022] Open
Abstract
Neurons project axons to local and distal sites and can display heterogeneous morphologies with limited physical dimensions that may influence the structure of large organelles such as mitochondria. Using cryo-electron tomography (cryo-ET), we characterized native environments within axons and presynaptic varicosities to examine whether spatial restrictions within these compartments influence the morphology of mitochondria. Segmented tomographic reconstructions revealed distinctive morphological characteristics of mitochondria residing at the narrowed boundary between presynaptic varicosities and axons with limited physical dimensions (approximately 80 nm), compared to mitochondria in nonspatially restricted environments. Furthermore, segmentation of the tomograms revealed discrete organizations between the inner and outer membranes, suggesting possible independent remodeling of each membrane in mitochondria at spatially restricted axonal/varicosity boundaries. Thus, cryo-ET of mitochondria within axonal subcompartments reveals that spatial restrictions do not obstruct mitochondria from residing within them, but limited available space can influence their gross morphology and the organization of the inner and outer membranes. These findings offer new perspectives on the influence of physical and spatial characteristics of cellular environments on mitochondrial morphology and highlight the potential for remarkable structural plasticity of mitochondria to adapt to spatial restrictions within axons. Neurons are complex cells that communicate with each other via axons that can extend over distances of a meter or longer. Axons place enormous demands on neuronal energy production, and to maintain connections with local and distal targets, neurons have efficient systems that transport mitochondria to areas of high energy consumption. However, axons show variable dimensions, sometimes thinning to a diameter significantly smaller than the standard diameter of mitochondria, raising the question of how mitochondrial structures can adapt to the local spatial environment. In the present study, we employed electron tomography to investigate the physical and structural relationships between thin axons and the mitochondria that reside within them. We discovered that mitochondria exhibit a remarkable constriction of outer and inner membrane structure in regions of restricted physical dimensions of the axonal space. These findings highlight the remarkable structural plasticity of mitochondria and the potential influence of available space within cells on the structure of mitochondria. Given that maintaining a population of properly localized mitochondria is necessary to support synaptic function, the findings also suggest an adaptive role for mitochondrial structure in facilitating efficient axonal transport.
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Affiliation(s)
- Tara D. Fischer
- Department of Neurobiology and Anatomy, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, The University of Texas Health Science Center at Houston, Houston, Texas, United States America
| | - Pramod K. Dash
- Department of Neurobiology and Anatomy, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- Vivian L. Smith Department of Neurosurgery, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Jun Liu
- Department of Pathology and Laboratory Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - M. Neal Waxham
- Department of Neurobiology and Anatomy, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- * E-mail:
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119
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Kiryu-Seo S, Kiyama H. Mitochondrial behavior during axon regeneration/degeneration in vivo. Neurosci Res 2018; 139:42-47. [PMID: 30179641 DOI: 10.1016/j.neures.2018.08.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 07/31/2018] [Accepted: 08/22/2018] [Indexed: 01/25/2023]
Abstract
Over the last decade, mitochondrial dynamics beyond function during axon regeneration/degeneration have received attention. Axons have an effective delivery system of mitochondria shuttling between soma and axonal terminals, due to their polarized structure. The proper axonal transport of mitochondria, coordinated with mitochondrial fission/fusion and clearance, is vital for supplying high power energy in injured axons. Many researchers have studied mitochondrial dynamics using in vitro cultured cells with significant progress reported. However, the in vitro culture system is missing a physiological environment including glial cells, immune cells, and endothelial cells, whose communications are indispensable to nerve regeneration/degeneration. In line with this, the understanding of mitochondrial behavior in injured axon in vivo is necessary for promoting the physiological understanding of damaged axons and the development of a therapeutic strategy. In this review, we focus on recent insights into in vivo mitochondrial dynamics during axonal regeneration/degeneration, and introduce the advances of mouse strains to visualize mitochondria in a neuron-specific or an injury-specific manner, which are extremely useful for nerve regeneration/degeneration studies.
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Affiliation(s)
- Sumiko Kiryu-Seo
- Department of Functional Anatomy and Neuroscience, Graduate School of Medicine, Nagoya University. 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Hiroshi Kiyama
- Department of Functional Anatomy and Neuroscience, Graduate School of Medicine, Nagoya University. 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
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120
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Nguyen HB, Sui Y, Thai TQ, Ikenaka K, Oda T, Ohno N. Decreased number and increased volume with mitochondrial enlargement of cerebellar synaptic terminals in a mouse model of chronic demyelination. Med Mol Morphol 2018; 51:208-216. [PMID: 29796936 DOI: 10.1007/s00795-018-0193-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 05/15/2018] [Indexed: 01/02/2023]
Abstract
Impaired nerve conduction, axonal degeneration, and synaptic alterations contribute to neurological disabilities in inflammatory demyelinating diseases. Cerebellar dysfunction is associated with demyelinating disorders, but the alterations of axon terminals in cerebellar gray matter during chronic demyelination are still unclear. We analyzed the morphological and ultrastructural changes of climbing fiber terminals in a mouse model of hereditary chronic demyelination. Three-dimensional ultrastructural analyses using serial block-face scanning electron microscopy and immunostaining for synaptic markers were performed in a demyelination mouse model caused by extra copies of myelin gene (PLP4e). At 1 month old, many myelinated axons were observed in PLP4e and wild-type mice, but demyelinated axons and axons with abnormally thin myelin were prominent in PLP4e mice at 5 months old. The density of climbing fiber terminals was significantly reduced in PLP4e mice at 5 months old. Reconstruction of climbing fiber terminals revealed that PLP4e climbing fibers had increased varicosity volume and enlarged mitochondria in the varicosities at 5-month-old mice. These results suggest that chronic demyelination is associated with alterations and loss of climbing fiber terminals in the cerebellar cortex, and that synaptic changes may contribute to cerebellar phenotypes observed in hereditary demyelinating disorders.
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Affiliation(s)
- Huy Bang Nguyen
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Japan.,Department of Anatomy and Structural Biology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Japan
| | - Yang Sui
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Japan.,Department of Anatomy and Structural Biology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Japan
| | - Truc Quynh Thai
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Japan.,Department of Anatomy and Structural Biology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Japan
| | - Kazuhiro Ikenaka
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Japan
| | - Toshiyuki Oda
- Department of Anatomy and Structural Biology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Japan
| | - Nobuhiko Ohno
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Japan. .,Department of Anatomy, Division of Histology and Cell Biology, School of Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke-shi, Tochigi, 329-0498, Japan.
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121
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Yellen G. Fueling thought: Management of glycolysis and oxidative phosphorylation in neuronal metabolism. J Cell Biol 2018; 217:2235-2246. [PMID: 29752396 PMCID: PMC6028533 DOI: 10.1083/jcb.201803152] [Citation(s) in RCA: 213] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 04/30/2018] [Accepted: 05/02/2018] [Indexed: 01/02/2023] Open
Abstract
Yellen reviews how cellular metabolism responds acutely to the intense energy requirements of neurons when they are stimulated. The brain’s energy demands are remarkable both in their intensity and in their moment-to-moment dynamic range. This perspective considers the evidence for Warburg-like aerobic glycolysis during the transient metabolic response of the brain to acute activation, and it particularly addresses the cellular mechanisms that underlie this metabolic response. The temporary uncoupling between glycolysis and oxidative phosphorylation led to the proposal of an astrocyte-to-neuron lactate shuttle whereby during stimulation, lactate produced by increased glycolysis in astrocytes is taken up by neurons as their primary energy source. However, direct evidence for this idea is lacking, and evidence rather supports that neurons have the capacity to increase their own glycolysis in response to stimulation; furthermore, neurons may export rather than import lactate in response to stimulation. The possible cellular mechanisms for invoking metabolic resupply of energy in neurons are also discussed, in particular the roles of feedback signaling via adenosine diphosphate and feedforward signaling by calcium ions.
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Affiliation(s)
- Gary Yellen
- Department of Neurobiology, Harvard Medical School, Boston, MA
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122
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Lieberman OJ, McGuirt AF, Tang G, Sulzer D. Roles for neuronal and glial autophagy in synaptic pruning during development. Neurobiol Dis 2018; 122:49-63. [PMID: 29709573 DOI: 10.1016/j.nbd.2018.04.017] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 03/22/2018] [Accepted: 04/24/2018] [Indexed: 12/29/2022] Open
Abstract
The dendritic protrusions known as spines represent the primary postsynaptic location for excitatory synapses. Dendritic spines are critical for many synaptic functions, and their formation, modification, and turnover are thought to be important for mechanisms of learning and memory. At many excitatory synapses, dendritic spines form during the early postnatal period, and while many spines are likely being formed and removed throughout life, the net number are often gradually "pruned" during adolescence to reach a stable level in the adult. In neurodevelopmental disorders, spine pruning is disrupted, emphasizing the importance of understanding its governing processes. Autophagy, a process through which cytosolic components and organelles are degraded, has recently been shown to control spine pruning in the mouse cortex, but the mechanisms through which autophagy acts remain obscure. Here, we draw on three widely studied prototypical synaptic pruning events to focus on two governing principles of spine pruning: 1) activity-dependent synaptic competition and 2) non-neuronal contributions. We briefly review what is known about autophagy in the central nervous system and its regulation by metabolic kinases. We propose a model in which autophagy in both neurons and non-neuronal cells contributes to spine pruning, and how other processes that regulate spine pruning could intersect with autophagy. We further outline future research directions to address outstanding questions on the role of autophagy in synaptic pruning.
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Affiliation(s)
- Ori J Lieberman
- Department of Psychiatry, Columbia University Medical Center, New York, NY 10032, United States
| | - Avery F McGuirt
- Department of Psychiatry, Columbia University Medical Center, New York, NY 10032, United States
| | - Guomei Tang
- Department of Neurology, Columbia University Medical Center, New York, NY 10032, United States
| | - David Sulzer
- Department of Psychiatry, Columbia University Medical Center, New York, NY 10032, United States; Department of Neurology, Columbia University Medical Center, New York, NY 10032, United States; Department of Pharmacology, Columbia University Medical Center, New York, NY 10032, United States; Research Foundation for Mental Hygiene, New York State Psychiatric Institute, New York, NY 10032, United States.
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123
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Monday HR, Younts TJ, Castillo PE. Long-Term Plasticity of Neurotransmitter Release: Emerging Mechanisms and Contributions to Brain Function and Disease. Annu Rev Neurosci 2018; 41:299-322. [PMID: 29709205 DOI: 10.1146/annurev-neuro-080317-062155] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Long-lasting changes of brain function in response to experience rely on diverse forms of activity-dependent synaptic plasticity. Chief among them are long-term potentiation and long-term depression of neurotransmitter release, which are widely expressed by excitatory and inhibitory synapses throughout the central nervous system and can dynamically regulate information flow in neural circuits. This review article explores recent advances in presynaptic long-term plasticity mechanisms and contributions to circuit function. Growing evidence indicates that presynaptic plasticity may involve structural changes, presynaptic protein synthesis, and transsynaptic signaling. Presynaptic long-term plasticity can alter the short-term dynamics of neurotransmitter release, thereby contributing to circuit computations such as novelty detection, modifications of the excitatory/inhibitory balance, and sensory adaptation. In addition, presynaptic long-term plasticity underlies forms of learning and its dysregulation participates in several neuropsychiatric conditions, including schizophrenia, autism, intellectual disabilities, neurodegenerative diseases, and drug abuse.
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Affiliation(s)
- Hannah R Monday
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461, USA;
| | - Thomas J Younts
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, United Kingdom
| | - Pablo E Castillo
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461, USA;
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124
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Picard M, McEwen BS, Epel ES, Sandi C. An energetic view of stress: Focus on mitochondria. Front Neuroendocrinol 2018; 49:72-85. [PMID: 29339091 PMCID: PMC5964020 DOI: 10.1016/j.yfrne.2018.01.001] [Citation(s) in RCA: 278] [Impact Index Per Article: 46.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 01/09/2018] [Accepted: 01/10/2018] [Indexed: 12/19/2022]
Abstract
Energy is required to sustain life and enable stress adaptation. At the cellular level, energy is largely derived from mitochondria - unique multifunctional organelles with their own genome. Four main elements connect mitochondria to stress: (1) Energy is required at the molecular, (epi)genetic, cellular, organellar, and systemic levels to sustain components of stress responses; (2) Glucocorticoids and other steroid hormones are produced and metabolized by mitochondria; (3) Reciprocally, mitochondria respond to neuroendocrine and metabolic stress mediators; and (4) Experimentally manipulating mitochondrial functions alters physiological and behavioral responses to psychological stress. Thus, mitochondria are endocrine organelles that provide both the energy and signals that enable and direct stress adaptation. Neural circuits regulating social behavior - as well as psychopathological processes - are also influenced by mitochondrial energetics. An integrative view of stress as an energy-driven process opens new opportunities to study mechanisms of adaptation and regulation across the lifespan.
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Affiliation(s)
- Martin Picard
- Department of Psychiatry, Division of Behavioral Medicine, Columbia University, Medical Center, New York, NY 10032, USA; Department of Neurology, The H. Houston Merritt Center, Columbia Translational Neuroscience Initiative, Columbia University Medical Center, New York, NY 10032, USA; Columbia Aging Center, Columbia University, New York, NY 10032, USA.
| | - Bruce S McEwen
- Laboratory for Neuroendocrinology, The Rockefeller University, New York, NY 10065, USA
| | - Elissa S Epel
- Department of Psychiatry, University of California, San Francisco, San Francisco, CA, USA
| | - Carmen Sandi
- Brain Mind Institute, Ecole Polytechnique Federale de Lausanne, EPFL, 1015 Lausanne, Switzerland
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125
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Zimin PI, Woods CB, Kayser EB, Ramirez JM, Morgan PG, Sedensky MM. Isoflurane disrupts excitatory neurotransmitter dynamics via inhibition of mitochondrial complex I. Br J Anaesth 2018; 120:1019-1032. [PMID: 29661379 DOI: 10.1016/j.bja.2018.01.036] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 01/08/2018] [Accepted: 02/09/2018] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The mechanisms of action of volatile anaesthetics are unclear. Volatile anaesthetics selectively inhibit complex I in the mitochondrial respiratory chain. Mice in which the mitochondrial complex I subunit NDUFS4 is knocked out [Ndufs4(KO)] either globally or in glutamatergic neurons are hypersensitive to volatile anaesthetics. The volatile anaesthetic isoflurane selectively decreases the frequency of spontaneous excitatory events in hippocampal slices from Ndufs4(KO) mice. METHODS Complex I inhibition by isoflurane was assessed with a Clark electrode. Synaptic function was measured by stimulating Schaffer collateral fibres and recording field potentials in the hippocampus CA1 region. RESULTS Isoflurane specifically inhibits complex I dependent respiration at lower concentrations in mitochondria from Ndufs4(KO) than from wild-type mice. In hippocampal slices, after high frequency stimulation to increase energetic demand, short-term synaptic potentiation is less in KO compared with wild-type mice. After high frequency stimulation, both Ndufs4(KO) and wild-type hippocampal slices exhibit striking synaptic depression in isoflurane at twice the 50% effective concentrations (EC50). The pattern of synaptic depression by isoflurane indicates a failure in synaptic vesicle recycling. Application of a selective A1 adenosine receptor antagonist partially eliminates isoflurane-induced short-term depression in both wild-type and Ndufs4(KO) slices, implicating an additional mitochondria-dependent effect on exocytosis. When mitochondria are the sole energy source, isoflurane completely eliminates synaptic output in both mutant and wild-type mice at twice the (EC50) for anaesthesia. CONCLUSIONS Volatile anaesthetics directly inhibit mitochondrial complex I as a primary target, limiting synaptic ATP production, and excitatory vesicle endocytosis and exocytosis.
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Affiliation(s)
- P I Zimin
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA.
| | - C B Woods
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - E B Kayser
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - J M Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Neurological Surgery, University of Washington, Seattle, WA, USA
| | - P G Morgan
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA
| | - M M Sedensky
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA
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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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127
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Robicsek O, Ene HM, Karry R, Ytzhaki O, Asor E, McPhie D, Cohen BM, Ben-Yehuda R, Weiner I, Ben-Shachar D. Isolated Mitochondria Transfer Improves Neuronal Differentiation of Schizophrenia-Derived Induced Pluripotent Stem Cells and Rescues Deficits in a Rat Model of the Disorder. Schizophr Bull 2018; 44:432-442. [PMID: 28586483 PMCID: PMC5814822 DOI: 10.1093/schbul/sbx077] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Dysfunction of mitochondria, key players in various essential cell processes, has been repeatedly reported in schizophrenia (SZ). Recently, several studies have reported functional recovery and cellular viability following mitochondrial transplantation, mostly in ischemia experimental models. Here, we aimed to demonstrate beneficial effects of isolated active normal mitochondria (IAN-MIT) transfer in vitro and in vivo, using SZ-derived induced pluripotent stem cells (iPSCs) differentiating into glutamatergic neuron, as well as a rodent model of SZ. First, we show that IAN-MIT enter various cell types without manipulation. Next, we show that IAN-MIT transfer into SZ-derived lymphoblasts induces long-lasting improvement in various mitochondrial functions including cellular oxygen consumption and mitochondrial membrane potential (Δ ψ m). We also demonstrate improved differentiation of SZ-derived iPSCs into neurons, by increased expression of neuronal and glutamatergic markers β3-tubulin, synapsin1, and Tbr1 and by an activation of the glutamate-glutamine cycle. In the animal model, we show that intra-prefrontal cortex injection of IAN-MIT in adolescent rats exposed prenatally to a viral mimic prevents mitochondrial Δ ψ m and attentional deficit at adulthood. Our results provide evidence for a direct link between mitochondrial function and SZ-related deficits both in vitro and in vivo and suggest a therapeutic potential for IAN-MIT transfer in diseases with bioenergetic and neurodevelopmental abnormalities such as SZ.
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Affiliation(s)
- Odile Robicsek
- Laboratory of Psychobiology, Department of Psychiatry, Rambam Health Care Campus, B. Rappaport Faculty of Medicine and Rappaport Family Institute for Research in Medical Sciences, Technion IIT, Haifa, Israel
| | - Hila M Ene
- Laboratory of Psychobiology, Department of Psychiatry, Rambam Health Care Campus, B. Rappaport Faculty of Medicine and Rappaport Family Institute for Research in Medical Sciences, Technion IIT, Haifa, Israel
| | - Rachel Karry
- Laboratory of Psychobiology, Department of Psychiatry, Rambam Health Care Campus, B. Rappaport Faculty of Medicine and Rappaport Family Institute for Research in Medical Sciences, Technion IIT, Haifa, Israel
| | - Ofer Ytzhaki
- Laboratory of Psychobiology, Department of Psychiatry, Rambam Health Care Campus, B. Rappaport Faculty of Medicine and Rappaport Family Institute for Research in Medical Sciences, Technion IIT, Haifa, Israel
| | - Eyal Asor
- Laboratory of Psychobiology, Department of Psychiatry, Rambam Health Care Campus, B. Rappaport Faculty of Medicine and Rappaport Family Institute for Research in Medical Sciences, Technion IIT, Haifa, Israel
| | - Donna McPhie
- Department of Psychiatry, Harvard Medical School, Boston, McLean Hospital, Belmont, MA
| | - Bruce M Cohen
- Department of Psychiatry, Harvard Medical School, Boston, McLean Hospital, Belmont, MA
| | - Rotem Ben-Yehuda
- School of Psychological Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Ina Weiner
- School of Psychological Sciences, Tel Aviv University, Tel Aviv, Israel,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Dorit Ben-Shachar
- Laboratory of Psychobiology, Department of Psychiatry, Rambam Health Care Campus, B. Rappaport Faculty of Medicine and Rappaport Family Institute for Research in Medical Sciences, Technion IIT, Haifa, Israel,To whom correspondence should be addressed; Laboratory of Psychobiology, Department of Psychiatry, Rambam Health Care Campus and B. Rappaport Faculty of Medicine, Technion ITT, POB 9649, Haifa 31096, Israel; tel: +972-4-8295224, fax: +972-4-8295220, e-mail:
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128
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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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129
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Chen F, Ardalan M, Elfving B, Wegener G, Madsen TM, Nyengaard JR. Mitochondria Are Critical for BDNF-Mediated Synaptic and Vascular Plasticity of Hippocampus following Repeated Electroconvulsive Seizures. Int J Neuropsychopharmacol 2017; 21:291-304. [PMID: 29228215 PMCID: PMC5838811 DOI: 10.1093/ijnp/pyx115] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 12/05/2017] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Electroconvulsive therapy is a fast-acting and efficient treatment of depression used in the clinic. The underlying mechanism of its therapeutic effect is still unclear. However, recovery of synaptic connections and synaptic remodeling is thought to play a critical role for the clinical efficacy obtained from a rapid antidepressant response. Here, we investigated the relationship between synaptic changes and concomitant nonneuronal changes in microvasculature and mitochondria and its relationship to brain-derived neurotrophic factor level changes after repeated electroconvulsive seizures, an animal model of electroconvulsive therapy. METHODS Electroconvulsive seizures or sham treatment was given daily for 10 days to rats displaying a genetically driven phenotype modelling clinical depression: the Flinders Sensitive and Resistant Line rats. Stereological principles were employed to quantify numbers of synapses and mitochondria, and the length of microvessels in the hippocampus. The brain-derived neurotrophic factor protein levels were quantified with immunohistochemistry. RESULTS In untreated controls, a lower number of synapses and mitochondria was accompanied by shorter microvessels of the hippocampus in "depressive" phenotype (Flinders Sensitive Line) compared with the "nondepressed" phenotype (Flinders Resistant Line). Electroconvulsive seizure administration significantly increased the number of synapses and mitochondria, and length of microvessels both in Flinders Sensitive Line-electroconvulsive seizures and Flinders Resistant Line-electroconvulsive seizures rats. In addition, the amount of brain-derived neurotrophic factor protein was significantly increased in Flinders Sensitive Line and Flinders Resistant Line rats after electroconvulsive seizures. Furthermore, there was a significant positive correlation between brain-derived neurotrophic factor level and mitochondria/synapses. CONCLUSION Our results indicate that rapid and efficient therapeutic effect of electroconvulsive seizures may be related to synaptic plasticity, accompanied by brain-derived neurotrophic factor protein level elevation and mitochondrial and vascular support.
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Affiliation(s)
- Fenghua Chen
- Core Center for Molecular Morphology, Section for Stereology and Microscopy, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark,Correspondence: Fenghua Chen, MD, PhD, Department of Clinical Medicine, Translational Neuropsychiatry Unit, Skovagervej 2, building 14K, 0.15, 8240 Risskov, Denmark ()
| | - Maryam Ardalan
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Risskov, Denmark,Center of Excellence for Pharmaceutical Sciences, North-West University, Potchefstroom, South Africa,Department of Clinical Medicine, Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | - Betina Elfving
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Risskov, Denmark
| | - Gregers Wegener
- AUGUST Centre, Department of Clinical Medicine, Aarhus University, Risskov, Denmark
| | | | - Jens R Nyengaard
- Core Center for Molecular Morphology, Section for Stereology and Microscopy, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark,Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University, Aarhus, Denmark
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130
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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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131
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DiNuzzo M, Nedergaard M. Brain energetics during the sleep-wake cycle. Curr Opin Neurobiol 2017; 47:65-72. [PMID: 29024871 PMCID: PMC5732842 DOI: 10.1016/j.conb.2017.09.010] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 09/06/2017] [Accepted: 09/16/2017] [Indexed: 12/11/2022]
Abstract
Brain activity during wakefulness is associated with high metabolic rates that are believed to support information processing and memory encoding. In spite of loss of consciousness, sleep still carries a substantial energy cost. Experimental evidence supports a cerebral metabolic shift taking place during sleep that suppresses aerobic glycolysis, a hallmark of environment-oriented waking behavior and synaptic plasticity. Recent studies reveal that glial astrocytes respond to the reduction of wake-promoting neuromodulators by regulating volume, composition and glymphatic drainage of interstitial fluid. These events are accompanied by changes in neuronal discharge patterns, astrocyte-neuron interactions, synaptic transactions and underlying metabolic features. Internally-generated neuronal activity and network homeostasis are proposed to account for the high sleep-related energy demand.
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Affiliation(s)
- Mauro DiNuzzo
- Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Maiken Nedergaard
- Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Center for Translational Neuromedicine, University of Rochester Medical School, Rochester, NY 14640, USA
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132
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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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133
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Allostatic load and comorbidities: A mitochondrial, epigenetic, and evolutionary perspective. Dev Psychopathol 2017; 28:1117-1146. [PMID: 27739386 DOI: 10.1017/s0954579416000730] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Stress-related pathophysiology drives comorbid trajectories that elude precise prediction. Allostatic load algorithms that quantify biological "wear and tear" represent a comprehensive approach to detect multisystemic disease processes of the mind and body. However, the multiple morbidities directly or indirectly related to stress physiology remain enigmatic. Our aim in this article is to propose that biological comorbidities represent discrete pathophysiological processes captured by measuring allostatic load. This has applications in research and clinical settings to predict physical and psychiatric comorbidities alike. The reader will be introduced to the concepts of allostasis, allostasic states, allostatic load, and allostatic overload as they relate to stress-related diseases and the proposed prediction of biological comorbidities that extend rather to understanding psychopathologies. In our transdisciplinary discussion, we will integrate perspectives related to (a) mitochondrial biology as a key player in the allostatic load time course toward diseases that "get under the skin and skull"; (b) epigenetics related to child maltreatment and biological embedding that shapes stress perception throughout lifespan development; and
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134
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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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136
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Cwerman-Thibault H, Lechauve C, Augustin S, Roussel D, Reboussin É, Mohammad A, Degardin-Chicaud J, Simonutti M, Liang H, Brignole-Baudouin F, Maron A, Debeir T, Corral-Debrinski M. Neuroglobin Can Prevent or Reverse Glaucomatous Progression in DBA/2J Mice. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2017; 5:200-220. [PMID: 28540323 PMCID: PMC5430497 DOI: 10.1016/j.omtm.2017.04.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 04/21/2017] [Indexed: 01/12/2023]
Abstract
Mitochondrial dysfunction is responsible for hereditary optic neuropathies. We wished to determine whether preserving mitochondrial bioenergetics could prevent optic neuropathy in a reliable model of glaucoma. DBA/2J mice exhibit elevated intraocular pressure, progressive degeneration of their retinal ganglion cells, and optic neuropathy that resembles glaucoma. We established that glaucoma in these mice is directly associated with mitochondrial dysfunction: respiratory chain activity was compromised in optic nerves 5 months before neuronal loss began, and the amounts of some mitochondrial proteins were reduced in retinas of glaucomatous mice. One of these proteins is neuroglobin, which has a neuroprotective function. Therefore, we investigated whether gene therapy aimed at restoring neuroglobin levels in the retina via ocular administration of an adeno-associated viral vector could reduce neuronal degeneration. The approach of treating 2-month-old mice impeded glaucoma development: few neurons died and respiratory chain activity and visual cortex activity were comparable to those in young, asymptomatic mice. When the treatment was performed in 8-month-old mice, the surviving neurons acquired new morphologic and functional properties, leading to the preservation of visual cortex activity and respiratory chain activity. The beneficial effects of neuroglobin in DBA/2J retinas confirm this protein to be a promising candidate for treating glaucoma.
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Affiliation(s)
- Hélène Cwerman-Thibault
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
- PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, 75019 Paris, France
| | - Christophe Lechauve
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
- Department of Hematology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Sébastien Augustin
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
| | - Delphine Roussel
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
- Institut du Cerveau et de la Moelle Épinière, Hôpital Pitié Salpêtrière, 75013 Paris, France
| | - Élodie Reboussin
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
| | - Ammara Mohammad
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
- Genomic Paris Centre, Institut de Biologie de l’Ecole normale supérieure, 46 rue d’Ulm, 75230 Paris, France
| | - Julie Degardin-Chicaud
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
| | - Manuel Simonutti
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
| | - Hong Liang
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
- CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC, 28 rue de Charenton, 75012 Paris, France
| | - Françoise Brignole-Baudouin
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
| | - Anne Maron
- Sanofi-Aventis, 94400 Vitry-sur-Seine, France
| | - Thomas Debeir
- Departments of Evaluation and Expertise Strategy, Science Policy and External Innovation, Sanofi, 75008 Paris, France
| | - Marisol Corral-Debrinski
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, 75012 Paris, France
- PROTECT, INSERM, Université Paris Diderot, Sorbonne Paris Cité, 75019 Paris, France
- Corresponding author: Marisol Corral-Debrinski, PROTECT, INSERM (UMR1141), Université Paris Diderot, Sorbonne Paris Cité, 48 Boulevard Sérurier, 75019 Paris, France.
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137
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Differential Presynaptic ATP Supply for Basal and High-Demand Transmission. J Neurosci 2017; 37:1888-1899. [PMID: 28093477 DOI: 10.1523/jneurosci.2712-16.2017] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Revised: 01/10/2017] [Accepted: 01/13/2017] [Indexed: 11/21/2022] Open
Abstract
The relative contributions of glycolysis and oxidative phosphorylation to neuronal presynaptic energy demands are unclear. In rat hippocampal neurons, ATP production by either glycolysis or oxidative phosphorylation alone sustained basal evoked synaptic transmission for up to 20 min. However, combined inhibition of both ATP sources abolished evoked transmission. Neither action potential propagation failure nor depressed Ca2+ influx explained loss of evoked synaptic transmission. Rather, inhibition of ATP synthesis caused massive spontaneous vesicle exocytosis, followed by arrested endocytosis, accounting for the disappearance of evoked postsynaptic currents. In contrast to its weak effects on basal transmission, inhibition of oxidative phosphorylation alone depressed recovery from vesicle depletion. Local astrocytic lactate shuttling was not required. Instead, either ambient monocarboxylates or neuronal glycolysis was sufficient to supply requisite substrate. In summary, basal transmission can be sustained by glycolysis, but strong presynaptic demands are met preferentially by oxidative phosphorylation, which can be maintained by bulk but not local monocarboxylates or by neuronal glycolysis.SIGNIFICANCE STATEMENT Neuronal energy levels are critical for proper CNS function, but the relative roles for the two main sources of ATP production, glycolysis and oxidative phosphorylation, in fueling presynaptic function in unclear. Either glycolysis or oxidative phosphorylation can fuel low-frequency synaptic function and inhibiting both underlies loss of synaptic transmission via massive vesicle release and subsequent failure to endocytose lost vesicles. Oxidative phosphorylation, fueled by either glycolysis or endogenously released monocarboxylates, can fuel more metabolically demanding tasks such as vesicle recovery after depletion. Our work demonstrates the flexible nature of fueling presynaptic function to maintain synaptic function.
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138
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Raefsky SM, Mattson MP. Adaptive responses of neuronal mitochondria to bioenergetic challenges: Roles in neuroplasticity and disease resistance. Free Radic Biol Med 2017; 102:203-216. [PMID: 27908782 PMCID: PMC5209274 DOI: 10.1016/j.freeradbiomed.2016.11.045] [Citation(s) in RCA: 157] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Accepted: 11/27/2016] [Indexed: 01/04/2023]
Abstract
An important concept in neurobiology is "neurons that fire together, wire together" which means that the formation and maintenance of synapses is promoted by activation of those synapses. Very similar to the effects of the stress of exercise on muscle cells, emerging findings suggest that neurons respond to activity by activating signaling pathways (e.g., Ca2+, CREB, PGC-1α, NF-κB) that stimulate mitochondrial biogenesis and cellular stress resistance. These pathways are also activated by aerobic exercise and food deprivation, two bioenergetic challenges of fundamental importance in the evolution of the brains of all mammals, including humans. The metabolic 'switch' in fuel source from liver glycogen store-derived glucose to adipose cell-derived fatty acids and their ketone metabolites during fasting and sustained exercise, appears to be a pivotal trigger of both brain-intrinsic and peripheral organ-derived signals that enhance learning and memory and underlying synaptic plasticity and neurogenesis. Brain-intrinsic extracellular signals include the excitatory neurotransmitter glutamate and the neurotrophic factor BDNF, and peripheral signals may include the liver-derived ketone 3-hydroxybutyrate and the muscle cell-derived protein irisin. Emerging findings suggest that fasting, exercise and an intellectually challenging lifestyle can protect neurons against the dysfunction and degeneration that they would otherwise suffer in acute brain injuries (stroke and head trauma) and neurodegenerative disorders including Alzheimer's, Parkinson's and Huntington's disease. Among the prominent intracellular responses of neurons to these bioenergetic challenges are up-regulation of antioxidant defenses, autophagy/mitophagy and DNA repair. A better understanding of such fundamental hormesis-based adaptive neuronal response mechanisms is expected to result in the development and implementation of novel interventions to promote optimal brain function and healthy brain aging.
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Affiliation(s)
- Sophia M Raefsky
- Laboratory of Neurosciences, National Institute on Aging, Baltimore, MD 21224, United States
| | - Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging, Baltimore, MD 21224, United States; Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, United States.
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139
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Vaccaro V, Devine MJ, Higgs NF, Kittler JT. Miro1-dependent mitochondrial positioning drives the rescaling of presynaptic Ca2+ signals during homeostatic plasticity. EMBO Rep 2016; 18:231-240. [PMID: 28039205 PMCID: PMC5286383 DOI: 10.15252/embr.201642710] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 11/16/2016] [Accepted: 11/28/2016] [Indexed: 11/27/2022] Open
Abstract
Mitochondrial trafficking is influenced by neuronal activity, but it remains unclear how mitochondrial positioning influences neuronal transmission and plasticity. Here, we use live cell imaging with the genetically encoded presynaptically targeted Ca2+ indicator, SyGCaMP5, to address whether presynaptic Ca2+ responses are altered by mitochondria in synaptic terminals. We find that presynaptic Ca2+ signals, as well as neurotransmitter release, are significantly decreased in terminals containing mitochondria. Moreover, the localisation of mitochondria at presynaptic sites can be altered during long‐term activity changes, dependent on the Ca2+‐sensing function of the mitochondrial trafficking protein, Miro1. In addition, we find that Miro1‐mediated activity‐dependent synaptic repositioning of mitochondria allows neurons to homeostatically alter the strength of presynaptic Ca2+ signals in response to prolonged changes in neuronal activity. Our results support a model in which mitochondria are recruited to presynaptic terminals during periods of raised neuronal activity and are involved in rescaling synaptic signals during homeostatic plasticity.
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Affiliation(s)
- Victoria Vaccaro
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Michael J Devine
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Nathalie F Higgs
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Josef T Kittler
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
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140
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Smith HL, Bourne JN, Cao G, Chirillo MA, Ostroff LE, Watson DJ, Harris KM. Mitochondrial support of persistent presynaptic vesicle mobilization with age-dependent synaptic growth after LTP. eLife 2016; 5. [PMID: 27991850 PMCID: PMC5235352 DOI: 10.7554/elife.15275] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 12/16/2016] [Indexed: 12/22/2022] Open
Abstract
Mitochondria support synaptic transmission through production of ATP, sequestration of calcium, synthesis of glutamate, and other vital functions. Surprisingly, less than 50% of hippocampal CA1 presynaptic boutons contain mitochondria, raising the question of whether synapses without mitochondria can sustain changes in efficacy. To address this question, we analyzed synapses from postnatal day 15 (P15) and adult rat hippocampus that had undergone theta-burst stimulation to produce long-term potentiation (TBS-LTP) and compared them to control or no stimulation. At 30 and 120 min after TBS-LTP, vesicles were decreased only in presynaptic boutons that contained mitochondria at P15, and vesicle decrement was greatest in adult boutons containing mitochondria. Presynaptic mitochondrial cristae were widened, suggesting a sustained energy demand. Thus, mitochondrial proximity reflected enhanced vesicle mobilization well after potentiation reached asymptote, in parallel with the apparently silent addition of new dendritic spines at P15 or the silent enlargement of synapses in adults. DOI:http://dx.doi.org/10.7554/eLife.15275.001
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Affiliation(s)
- Heather L Smith
- Department of Neuroscience, Center for Learning and Memory, Institute for Neuroscience, University of Texas at Austin, Austin, United States
| | - Jennifer N Bourne
- Department of Cell and Developmental Biology, University of Colorado Denver - Anschutz Medical Campus, Aurora, United States
| | - Guan Cao
- Department of Neuroscience, Center for Learning and Memory, Institute for Neuroscience, University of Texas at Austin, Austin, United States
| | - Michael A Chirillo
- Department of Neuroscience, Center for Learning and Memory, Institute for Neuroscience, University of Texas at Austin, Austin, United States
| | - Linnaea E Ostroff
- Center for Neural Science, New York University, Washington, New York
| | - Deborah J Watson
- Department of Neuroscience, Center for Learning and Memory, Institute for Neuroscience, University of Texas at Austin, Austin, United States
| | - Kristen M Harris
- Department of Neuroscience, Center for Learning and Memory, Institute for Neuroscience, University of Texas at Austin, Austin, United States
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141
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Kitahara Y, Nishi A. Antidepressant-induced changes in synaptic morphology in the mouse dentate gyrus. Nihon Yakurigaku Zasshi 2016; 148:180-184. [PMID: 27725565 DOI: 10.1254/fpj.148.180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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142
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Smit-Rigter L, Rajendran R, Silva CAP, Spierenburg L, Groeneweg F, Ruimschotel EM, van Versendaal D, van der Togt C, Eysel UT, Heimel JA, Lohmann C, Levelt CN. Mitochondrial Dynamics in Visual Cortex Are Limited In Vivo and Not Affected by Axonal Structural Plasticity. Curr Biol 2016; 26:2609-2616. [PMID: 27641766 DOI: 10.1016/j.cub.2016.07.033] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 06/30/2016] [Accepted: 07/13/2016] [Indexed: 12/30/2022]
Abstract
Mitochondria buffer intracellular Ca2+ and provide energy [1]. Because synaptic structures with high Ca2+ buffering [2-4] or energy demand [5] are often localized far away from the soma, mitochondria are actively transported to these sites [6-11]. Also, the removal and degradation of mitochondria are tightly regulated [9, 12, 13], because dysfunctional mitochondria are a source of reactive oxygen species, which can damage the cell [14]. Deficits in mitochondrial trafficking have been proposed to contribute to the pathogenesis of Parkinson's disease, schizophrenia, amyotrophic lateral sclerosis, optic atrophy, and Alzheimer's disease [13, 15-19]. In neuronal cultures, about a third of mitochondria are motile, whereas the majority remains stationary for several days [8, 20]. Activity-dependent mechanisms cause mitochondria to stop at synaptic sites [7, 8, 20, 21], which affects synapse function and maintenance. Reducing mitochondrial content in dendrites decreases spine density [22, 23], whereas increasing mitochondrial content or activity increases it [7]. These bidirectional interactions between synaptic activity and mitochondrial trafficking suggest that mitochondria may regulate synaptic plasticity. Here we investigated the dynamics of mitochondria in relation to axonal boutons of neocortical pyramidal neurons for the first time in vivo. We find that under these circumstances practically all mitochondria are stationary, both during development and in adulthood. In adult visual cortex, mitochondria are preferentially localized at putative boutons, where they remain for several days. Retinal-lesion-induced cortical plasticity increases turnover of putative boutons but leaves mitochondrial turnover unaffected. We conclude that in visual cortex in vivo, mitochondria are less dynamic than in vitro, and that structural plasticity does not affect mitochondrial dynamics.
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Affiliation(s)
- Laura Smit-Rigter
- Department of Molecular Visual Plasticity, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, the Netherlands
| | - Rajeev Rajendran
- Department of Molecular Visual Plasticity, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, the Netherlands
| | - Catia A P Silva
- Department of Synapse and Network Development, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, the Netherlands
| | - Liselot Spierenburg
- Department of Molecular Visual Plasticity, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, the Netherlands
| | - Femke Groeneweg
- Department of Synapse and Network Development, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, the Netherlands
| | - Emma M Ruimschotel
- Department of Molecular Visual Plasticity, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, the Netherlands
| | - Danielle van Versendaal
- Department of Molecular Visual Plasticity, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, the Netherlands
| | - Chris van der Togt
- Department of Molecular Visual Plasticity, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, the Netherlands
| | - Ulf T Eysel
- Department of Neurophysiology, Faculty of Medicine, Ruhr University Bochum, Universitätsstrasse 150, 44801 Bochum, Germany
| | - J Alexander Heimel
- Department of Cortical Structure and Function, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, the Netherlands
| | - Christian Lohmann
- Department of Synapse and Network Development, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, the Netherlands
| | - Christiaan N Levelt
- Department of Molecular Visual Plasticity, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, the Netherlands; Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, de Boelelaan 1085, 1081 HV, the Netherlands.
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143
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Lujan B, Kushmerick C, Banerjee TD, Dagda RK, Renden R. Glycolysis selectively shapes the presynaptic action potential waveform. J Neurophysiol 2016; 116:2523-2540. [PMID: 27605535 DOI: 10.1152/jn.00629.2016] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 09/05/2016] [Indexed: 11/22/2022] Open
Abstract
Mitochondria are major suppliers of cellular energy in neurons; however, utilization of energy from glycolysis vs. mitochondrial oxidative phosphorylation (OxPhos) in the presynaptic compartment during neurotransmission is largely unknown. Using presynaptic and postsynaptic recordings from the mouse calyx of Held, we examined the effect of acute selective pharmacological inhibition of glycolysis or mitochondrial OxPhos on multiple mechanisms regulating presynaptic function. Inhibition of glycolysis via glucose depletion and iodoacetic acid (1 mM) treatment, but not mitochondrial OxPhos, rapidly altered transmission, resulting in highly variable, oscillating responses. At reduced temperature, this same treatment attenuated synaptic transmission because of a smaller and broader presynaptic action potential (AP) waveform. We show via experimental manipulation and ion channel modeling that the altered AP waveform results in smaller Ca2+ influx, resulting in attenuated excitatory postsynaptic currents (EPSCs). In contrast, inhibition of mitochondria-derived ATP production via extracellular pyruvate depletion and bath-applied oligomycin (1 μM) had no significant effect on Ca2+ influx and did not alter the AP waveform within the same time frame (up to 30 min), and the resultant EPSC remained unaffected. Glycolysis, but not mitochondrial OxPhos, is thus required to maintain basal synaptic transmission at the presynaptic terminal. We propose that glycolytic enzymes are closely apposed to ATP-dependent ion pumps on the presynaptic membrane. Our results indicate a novel mechanism for the effect of hypoglycemia on neurotransmission. Attenuated transmission likely results from a single presynaptic mechanism at reduced temperature: a slower, smaller AP, before and independent of any effect on synaptic vesicle release or receptor activity.
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Affiliation(s)
- Brendan Lujan
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, Nevada
| | - Christopher Kushmerick
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Minas Gerais, Brazil; and
| | - Tania Das Banerjee
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, Nevada
| | - Ruben K Dagda
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, Nevada
| | - Robert Renden
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, Nevada;
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144
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Picard M, Wallace DC, Burelle Y. The rise of mitochondria in medicine. Mitochondrion 2016; 30:105-16. [PMID: 27423788 PMCID: PMC5023480 DOI: 10.1016/j.mito.2016.07.003] [Citation(s) in RCA: 300] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 07/04/2016] [Accepted: 07/12/2016] [Indexed: 12/11/2022]
Abstract
Once considered exclusively the cell's powerhouse, mitochondria are now recognized to perform multiple essential functions beyond energy production, impacting most areas of cell biology and medicine. Since the emergence of molecular biology and the discovery of pathogenic mitochondrial DNA defects in the 1980's, research advances have revealed a number of common human diseases which share an underlying pathogenesis involving mitochondrial dysfunction. Mitochondria undergo function-defining dynamic shape changes, communicate with each other, regulate gene expression within the nucleus, modulate synaptic transmission within the brain, release molecules that contribute to oncogenic transformation and trigger inflammatory responses systemically, and influence the regulation of complex physiological systems. Novel mitopathogenic mechanisms are thus being uncovered across a number of medical disciplines including genetics, oncology, neurology, immunology, and critical care medicine. Increasing knowledge of the bioenergetic aspects of human disease has provided new opportunities for diagnosis, therapy, prevention, and in connecting various domains of medicine. In this article, we overview specific aspects of mitochondrial biology that have contributed to - and likely will continue to enhance the progress of modern medicine.
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Affiliation(s)
- Martin Picard
- Department of Psychiatry, Division of Behavioral Medicine, Columbia University Medical Center, New York, NY, USA; Department of Neurology and CTNI, H Houston Merritt Center, Columbia University Medical Center, New York, NY, USA.
| | - Douglas C Wallace
- The Center for Mitochondrial and Epigenomic Medicine, Children's Hospital of Philadelphia and Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yan Burelle
- Faculty of Pharmacy, Université de Montreal, Montreal, QC, Canada
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145
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Drago I, Davis RL. Inhibiting the Mitochondrial Calcium Uniporter during Development Impairs Memory in Adult Drosophila. Cell Rep 2016; 16:2763-2776. [PMID: 27568554 DOI: 10.1016/j.celrep.2016.08.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/01/2016] [Accepted: 08/03/2016] [Indexed: 01/25/2023] Open
Abstract
The uptake of cytoplasmic calcium into mitochondria is critical for a variety of physiological processes, including calcium buffering, metabolism, and cell survival. Here, we demonstrate that inhibiting the mitochondrial calcium uniporter in the Drosophila mushroom body neurons (MBn)-a brain region critical for olfactory memory formation-causes memory impairment without altering the capacity to learn. Inhibiting uniporter activity only during pupation impaired adult memory, whereas the same inhibition during adulthood was without effect. The behavioral impairment was associated with structural defects in MBn, including a decrease in synaptic vesicles and an increased length in the axons of the αβ MBn. Our results reveal an in vivo developmental role for the mitochondrial uniporter complex in establishing the necessary structural and functional neuronal substrates for normal memory formation in the adult organism.
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Affiliation(s)
- Ilaria Drago
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, FL 33458, USA
| | - Ronald L Davis
- Department of Neuroscience, The Scripps Research Institute Florida, Jupiter, FL 33458, USA.
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146
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Imaging of neuronal mitochondria in situ. Curr Opin Neurobiol 2016; 39:152-63. [PMID: 27454347 DOI: 10.1016/j.conb.2016.06.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 06/04/2016] [Accepted: 06/07/2016] [Indexed: 11/21/2022]
Abstract
Neuronal mitochondria are receiving a rapidly increasing level of attention. This is to a significant part due to the ability to visualize neuronal mitochondria in novel ways, especially in vivo. Such an approach allows studying neuronal mitochondria in an intact tissue context, during different developmental states and in various genetic backgrounds and disease conditions. Hence, in vivo imaging of mitochondria in the nervous system can reveal aspects of the 'mitochondrial life cycle' in neurons that hitherto have remained obscure or could only be inferred indirectly. In this survey of the current literature, we review the new insights that have emerged from studies using mitochondrial imaging in intact neural preparations ranging from worms to mice.
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147
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Kwon SK, Sando R, Lewis TL, Hirabayashi Y, Maximov A, Polleux F. LKB1 Regulates Mitochondria-Dependent Presynaptic Calcium Clearance and Neurotransmitter Release Properties at Excitatory Synapses along Cortical Axons. PLoS Biol 2016; 14:e1002516. [PMID: 27429220 PMCID: PMC4948842 DOI: 10.1371/journal.pbio.1002516] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 06/21/2016] [Indexed: 12/24/2022] Open
Abstract
Individual synapses vary significantly in their neurotransmitter release properties, which underlie complex information processing in neural circuits. Presynaptic Ca2+ homeostasis plays a critical role in specifying neurotransmitter release properties, but the mechanisms regulating synapse-specific Ca2+ homeostasis in the mammalian brain are still poorly understood. Using electrophysiology and genetically encoded Ca2+ sensors targeted to the mitochondrial matrix or to presynaptic boutons of cortical pyramidal neurons, we demonstrate that the presence or absence of mitochondria at presynaptic boutons dictates neurotransmitter release properties through Mitochondrial Calcium Uniporter (MCU)-dependent Ca2+ clearance. We demonstrate that the serine/threonine kinase LKB1 regulates MCU expression, mitochondria-dependent Ca2+ clearance, and thereby, presynaptic release properties. Re-establishment of MCU-dependent mitochondrial Ca2+ uptake at glutamatergic synapses rescues the altered neurotransmitter release properties characterizing LKB1-null cortical axons. Our results provide novel insights into the cellular and molecular mechanisms whereby mitochondria control neurotransmitter release properties in a bouton-specific way through presynaptic Ca2+ clearance.
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Affiliation(s)
- Seok-Kyu Kwon
- Columbia University Medical Center, Department of Neuroscience, Mortimer B. Zuckerman Mind Brain Behavior Institute, Kavli Institute for Brain Science, New York, New York, United States of America
| | - Richard Sando
- The Scripps Research Institute, Dorris Neuroscience Center, La Jolla, California, United States of America
| | - Tommy L. Lewis
- Columbia University Medical Center, Department of Neuroscience, Mortimer B. Zuckerman Mind Brain Behavior Institute, Kavli Institute for Brain Science, New York, New York, United States of America
| | - Yusuke Hirabayashi
- Columbia University Medical Center, Department of Neuroscience, Mortimer B. Zuckerman Mind Brain Behavior Institute, Kavli Institute for Brain Science, New York, New York, United States of America
| | - Anton Maximov
- The Scripps Research Institute, Dorris Neuroscience Center, La Jolla, California, United States of America
| | - Franck Polleux
- Columbia University Medical Center, Department of Neuroscience, Mortimer B. Zuckerman Mind Brain Behavior Institute, Kavli Institute for Brain Science, New York, New York, United States of America
- * E-mail:
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148
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Disrupted-in-schizophrenia 1 (DISC1) and Syntaphilin collaborate to modulate axonal mitochondrial anchoring. Mol Brain 2016; 9:69. [PMID: 27370822 PMCID: PMC4930613 DOI: 10.1186/s13041-016-0250-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 06/24/2016] [Indexed: 01/28/2023] Open
Abstract
In neuronal axons, the ratio of motile-to-stationary mitochondria is tightly regulated by neuronal activation, thereby meeting the need for local calcium buffering and maintaining the ATP supply. However, the molecular players and detailed regulatory mechanisms behind neuronal mitochondrial movement are not completely understood. Here, we found that neuronal activation-induced mitochondrial anchoring is regulated by Disrupted-in-schizophrenia 1 (DISC1), which is accomplished by functional association with Syntaphilin (SNPH). DISC1 deficiency resulted in reduced axonal mitochondrial movement, which was partially reversed by concomitant SNPH depletion. In addition, a SNPH deletion mutant lacking the sequence for interaction with DISC1 exhibited an enhanced mitochondrial anchoring effect than wild-type SNPH. Moreover, upon neuronal activation, mitochondrial movement was preserved by DISC1 overexpression, not showing immobilized response of mitochondria. Taken together, we propose that DISC1 in association with SNPH is a component of a modulatory complex that determines mitochondrial anchoring in response to neuronal activation.
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149
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Kiryu-Seo S, Tamada H, Kato Y, Yasuda K, Ishihara N, Nomura M, Mihara K, Kiyama H. Mitochondrial fission is an acute and adaptive response in injured motor neurons. Sci Rep 2016; 6:28331. [PMID: 27319806 PMCID: PMC4913268 DOI: 10.1038/srep28331] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 06/02/2016] [Indexed: 12/03/2022] Open
Abstract
Successful recovery from neuronal damage requires a huge energy supply, which is provided by mitochondria. However, the physiological relevance of mitochondrial dynamics in damaged neurons in vivo is poorly understood. To address this issue, we established unique bacterial artificial chromosome transgenic (BAC Tg) mice, which develop and function normally, but in which neuronal injury induces labelling of mitochondria with green fluorescent protein (GFP) and expression of cre recombinase. GFP-labelled mitochondria in BAC Tg mice appear shorter in regenerating motor axons soon after nerve injury compared with mitochondria in non-injured axons, suggesting the importance of increased mitochondrial fission during the early phase of nerve regeneration. Crossing the BAC Tg mice with mice carrying a floxed dynamin-related protein 1 gene (Drp1), which is necessary for mitochondrial fission, ablates mitochondrial fission specifically in injured neurons. Injury-induced Drp1-deficient motor neurons show elongated or abnormally gigantic mitochondria, which have impaired membrane potential and axonal transport velocity during the early phase after injury, and eventually promote neuronal death. Our in vivo data suggest that acute and prominent mitochondrial fission during the early stage after nerve injury is an adaptive response and is involved in the maintenance of mitochondrial and neuronal integrity to prevent neurodegeneration.
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Affiliation(s)
- Sumiko Kiryu-Seo
- Department of Functional Anatomy and Neuroscience, Graduate School of Medicine, Nagoya University, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.,CREST, JST, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Hiromi Tamada
- Department of Functional Anatomy and Neuroscience, Graduate School of Medicine, Nagoya University, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Yukina Kato
- Department of Functional Anatomy and Neuroscience, Graduate School of Medicine, Nagoya University, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Katsura Yasuda
- Department of Functional Anatomy and Neuroscience, Graduate School of Medicine, Nagoya University, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Naotada Ishihara
- Department of Protein Biochemistry, Institute of Life Science, Kurume University, Kurume 839-0864, Japan
| | - Masatoshi Nomura
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Science, Kyushu University,Fukuoka 812-8382, Japan
| | - Katsuyoshi Mihara
- Department of Molecular Biology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8382, Japan
| | - Hiroshi Kiyama
- Department of Functional Anatomy and Neuroscience, Graduate School of Medicine, Nagoya University, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.,CREST, JST, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
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150
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Mitochondrial function in hypoxic ischemic injury and influence of aging. Prog Neurobiol 2016; 157:92-116. [PMID: 27321753 DOI: 10.1016/j.pneurobio.2016.06.006] [Citation(s) in RCA: 242] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 03/30/2016] [Accepted: 06/12/2016] [Indexed: 12/11/2022]
Abstract
Mitochondria are a major target in hypoxic/ischemic injury. Mitochondrial impairment increases with age leading to dysregulation of molecular pathways linked to mitochondria. The perturbation of mitochondrial homeostasis and cellular energetics worsens outcome following hypoxic-ischemic insults in elderly individuals. In response to acute injury conditions, cellular machinery relies on rapid adaptations by modulating posttranslational modifications. Therefore, post-translational regulation of molecular mediators such as hypoxia-inducible factor 1α (HIF-1α), peroxisome proliferator-activated receptor γ coactivator α (PGC-1α), c-MYC, SIRT1 and AMPK play a critical role in the control of the glycolytic-mitochondrial energy axis in response to hypoxic-ischemic conditions. The deficiency of oxygen and nutrients leads to decreased energetic reliance on mitochondria, promoting glycolysis. The combination of pseudohypoxia, declining autophagy, and dysregulation of stress responses with aging adds to impaired host response to hypoxic-ischemic injury. Furthermore, intermitochondrial signal propagation and tissue wide oscillations in mitochondrial metabolism in response to oxidative stress are emerging as vital to cellular energetics. Recently reported intercellular transport of mitochondria through tunneling nanotubes also play a role in the response to and treatments for ischemic injury. In this review we attempt to provide an overview of some of the molecular mechanisms and potential therapies involved in the alteration of cellular energetics with aging and injury with a neurobiological perspective.
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