51
|
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.
Collapse
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.
| |
Collapse
|
52
|
Porat-Shliom N, Harding OJ, Malec L, Narayan K, Weigert R. Mitochondrial Populations Exhibit Differential Dynamic Responses to Increased Energy Demand during Exocytosis In Vivo. iScience 2019; 11:440-449. [PMID: 30661001 PMCID: PMC6355620 DOI: 10.1016/j.isci.2018.12.036] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 10/14/2018] [Accepted: 12/28/2018] [Indexed: 12/15/2022] Open
Abstract
Mitochondria are dynamic organelles undergoing fission, fusion, and translocation. These processes have been studied in cultured cells; however, little is known about their regulation in cells within tissues in vivo. We applied four-dimensional intravital microscopy to address this in secretory cells of the salivary gland. We found that mitochondria are organized in two populations: one juxtaposed to the basolateral plasma membrane and the other dispersed in the cytosol. Under basal conditions, central mitochondria exhibit microtubule-dependent motility and low fusion rate, whereas basolateral mitochondria are static and display high fusion rate. Increasing cellular energy demand by β-adrenergic stimulation of regulated exocytosis selectively enhanced motility and fusion of central mitochondria. Inhibition of microtubule polymerization led to inhibition of central mitochondrial motility and fusion and a marked reduction in exocytosis. This study reveals a conserved heterogeneity in mitochondrial positioning and dynamics in exocrine tissues that may have fundamental implications in organ pathophysiology. In the salivary glands, mitochondria exist in two populations: basolateral and central Basolateral mitochondria are static and frequently fuse Central mitochondria are highly motile and rarely fuse Exocytosis elicits selective, microtubule-dependent response in central mitochondria
Collapse
Affiliation(s)
- Natalie Porat-Shliom
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA; National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA; Cell Biology and Imaging Section, Thoracic and Gastrointestinal Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Olivia J Harding
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lenka Malec
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kedar Narayan
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 8560 Progress Drive, Frederick, MD 21701, USA; Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Roberto Weigert
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA; National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA.
| |
Collapse
|
53
|
Rangaraju V, Lauterbach M, Schuman EM. Spatially Stable Mitochondrial Compartments Fuel Local Translation during Plasticity. Cell 2019; 176:73-84.e15. [PMID: 30612742 DOI: 10.1016/j.cell.2018.12.013] [Citation(s) in RCA: 174] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 09/19/2018] [Accepted: 12/07/2018] [Indexed: 12/11/2022]
Abstract
Local translation meets protein turnover and plasticity demands at synapses, however, the location of its energy supply is unknown. We found that local translation in neurons is powered by mitochondria and not by glycolysis. Super-resolution microscopy revealed that dendritic mitochondria exist as stable compartments of single or multiple filaments. To test if these mitochondrial compartments can serve as local energy supply for synaptic translation, we stimulated individual synapses to induce morphological plasticity and visualized newly synthesized proteins. Depletion of local mitochondrial compartments abolished both the plasticity and the stimulus-induced synaptic translation. These mitochondrial compartments serve as spatially confined energy reserves, as local depletion of a mitochondrial compartment did not affect synaptic translation at remote spines. The length and stability of dendritic mitochondrial compartments and the spatial functional domain were altered by cytoskeletal disruption. These results indicate that cytoskeletally tethered local energy compartments exist in dendrites to fuel local translation during synaptic plasticity.
Collapse
Affiliation(s)
- Vidhya Rangaraju
- Max Planck Institute for Brain Research, Frankfurt 60438, Germany
| | | | - Erin M Schuman
- Max Planck Institute for Brain Research, Frankfurt 60438, Germany.
| |
Collapse
|
54
|
Fletcher LN, Williams SR. Neocortical Topology Governs the Dendritic Integrative Capacity of Layer 5 Pyramidal Neurons. Neuron 2019; 101:76-90.e4. [DOI: 10.1016/j.neuron.2018.10.048] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 08/03/2018] [Accepted: 10/25/2018] [Indexed: 10/27/2022]
|
55
|
Divakaruni SS, Van Dyke AM, Chandra R, LeGates TA, Contreras M, Dharmasri PA, Higgs HN, Lobo MK, Thompson SM, Blanpied TA. Long-Term Potentiation Requires a Rapid Burst of Dendritic Mitochondrial Fission during Induction. Neuron 2018; 100:860-875.e7. [PMID: 30318410 DOI: 10.1016/j.neuron.2018.09.025] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 08/09/2018] [Accepted: 09/14/2018] [Indexed: 12/22/2022]
Abstract
Synaptic transmission is bioenergetically demanding, and the diverse processes underlying synaptic plasticity elevate these demands. Therefore, mitochondrial functions, including ATP synthesis and Ca2+ handling, are likely essential for plasticity. Although axonal mitochondria have been extensively analyzed, LTP is predominantly induced postsynaptically, where mitochondria are understudied. Additionally, though mitochondrial fission is essential for their function, signaling pathways that regulate fission in neurons remain poorly understood. We found that NMDAR-dependent LTP induction prompted a rapid burst of dendritic mitochondrial fission and elevations of mitochondrial matrix Ca2+. The fission burst was triggered by cytosolic Ca2+ elevation and required CaMKII, actin, and Drp1, as well as dynamin 2. Preventing fission impaired mitochondrial matrix Ca2+ elevations, structural LTP in cultured neurons, and electrophysiological LTP in hippocampal slices. These data illustrate a novel pathway whereby synaptic activity controls mitochondrial fission and show that dynamic control of fission regulates plasticity induction, perhaps by modulating mitochondrial Ca2+ handling.
Collapse
Affiliation(s)
- Sai Sachin Divakaruni
- Medical Scientist Training Program, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Adam M Van Dyke
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Ramesh Chandra
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Tara A LeGates
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Minerva Contreras
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Poorna A Dharmasri
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Henry N Higgs
- Department of Biochemistry, Geisel School of Medicine at Dartmouth College, Hanover, NH 03755, USA
| | - Mary Kay Lobo
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Scott M Thompson
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Thomas A Blanpied
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| |
Collapse
|
56
|
Lee A, Hirabayashi Y, Kwon SK, Lewis TL, Polleux F. Emerging roles of mitochondria in synaptic transmission and neurodegeneration. CURRENT OPINION IN PHYSIOLOGY 2018; 3:82-93. [PMID: 30320242 PMCID: PMC6178220 DOI: 10.1016/j.cophys.2018.03.009] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mitochondria play numerous critical physiological functions in neurons including ATP production, Ca2+ regulation, lipid synthesis, ROS signaling, and the ability to trigger apoptosis. Recently developed technologies, including in vivo 2-photon imaging in awake behaving mice revealed that unlike in the peripheral nervous system (PNS), mitochondrial transport decreases strikingly along the axons of adult neurons of the central nervous system (CNS). Furthermore, the improvements of genetically-encoded biosensors have enabled precise monitoring of the spatial and temporal impact of mitochondria on Ca2+, ATP and ROS homeostasis in a compartment-specific manner. Here, we discuss recent findings that begin to unravel novel physiological and pathophysiological properties of neuronal mitochondria at synapses. We also suggest new directions in the exploration of mitochondrial function in synaptic transmission, plasticity and neurodegeneration.
Collapse
Affiliation(s)
- Annie Lee
- Department of Neuroscience, Columbia University, New York, NY 10032, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute
| | - Yusuke Hirabayashi
- Department of Neuroscience, Columbia University, New York, NY 10032, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute
| | - Seok-Kyu Kwon
- Department of Neuroscience, Columbia University, New York, NY 10032, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute
| | - Tommy L. Lewis
- Department of Neuroscience, Columbia University, New York, NY 10032, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute
| | - Franck Polleux
- Department of Neuroscience, Columbia University, New York, NY 10032, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute
- Kavli Institute for Brain Science at Columbia University
| |
Collapse
|
57
|
MCU Interacts with Miro1 to Modulate Mitochondrial Functions in Neurons. J Neurosci 2018; 38:4666-4677. [PMID: 29686046 DOI: 10.1523/jneurosci.0504-18.2018] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 04/11/2018] [Accepted: 04/17/2018] [Indexed: 11/21/2022] Open
Abstract
Mitochondrial Ca2+ uptake is gated by the mitochondrial calcium uniplex, which is comprised of mitochondrial calcium uniporter (MCU), the Ca2+ pore-forming subunit of the complex, and its regulators. Ca2+ influx through MCU affects both mitochondrial function and movement in neurons, but its direct role in mitochondrial movement has not been explored. In this report, we show a link between MCU and Miro1, a membrane protein known to regulate mitochondrial movement. We find that MCU interacts with Miro1 through MCU's N-terminal domain, previously thought to be the mitochondrial targeting sequence. Our results show that the N-terminus of MCU has a transmembrane domain that traverses the outer mitochondrial membrane, which is dispensable for MCU localization into mitochondria. However, this domain is required for Miro1 interaction and is critical for Miro1 directed movement. Together, our findings reveal Miro1 as a new component of the MCU complex, and that MCU is an important regulator of mitochondrial transport.SIGNIFICANCE STATEMENT Mitochondrial calcium level is critical for mitochondrial metabolic activity and mitochondrial transport in neurons. While it has been established that calcium influx into mitochondria is modulated by mitochondrial calcium uniporter (MCU) complex, how MCU regulates mitochondrial movement still remains unclear. Here, we discover that the N-terminus of MCU plays a different role than previously thought; it is not required for mitochondrial targeting but is essential for interaction with Miro1, an outer mitochondrial membrane protein important for mitochondrial movement. Furthermore, we show that MCU-Miro1 interaction is required to maintain mitochondrial transport. Our data identify that Miro1 is a novel component of the mitochondrial calcium uniplex and demonstrate that coupling between MCU and Miro1 as a novel mechanism modulating both mitochondrial Ca2+ uptake and mitochondrial transport.
Collapse
|
58
|
Vagnoni A, Bullock SL. A cAMP/PKA/Kinesin-1 Axis Promotes the Axonal Transport of Mitochondria in Aging Drosophila Neurons. Curr Biol 2018; 28:1265-1272.e4. [PMID: 29606421 PMCID: PMC5912900 DOI: 10.1016/j.cub.2018.02.048] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 01/10/2018] [Accepted: 02/19/2018] [Indexed: 11/15/2022]
Abstract
Mitochondria play fundamental roles within cells, including energy provision, calcium homeostasis, and the regulation of apoptosis. The transport of mitochondria by microtubule-based motors is critical for neuronal structure and function. This process allows local requirements for mitochondrial functions to be met and also facilitates recycling of these organelles [1, 2]. An age-related reduction in mitochondrial transport has been observed in neurons of mammalian and non-mammalian organisms [3, 4, 5, 6], and has been proposed to contribute to the broader decline in neuronal function that occurs during aging [3, 5, 6, 7]. However, the factors that influence mitochondrial transport in aging neurons are poorly understood. Here we provide evidence using the tractable Drosophila wing nerve system that the cyclic AMP/protein kinase A (cAMP/PKA) pathway promotes the axonal transport of mitochondria in adult neurons. The level of the catalytic subunit of PKA decreases during aging, and acute activation of the cAMP/PKA pathway in aged flies strongly stimulates mitochondrial motility. Thus, the age-related impairment of transport is reversible. The expression of many genes is increased by PKA activation in aged flies. However, our results indicate that elevated mitochondrial transport is due in part to upregulation of the heavy chain of the kinesin-1 motor, the level of which declines during aging. Our study identifies evolutionarily conserved factors that can strongly influence mitochondrial motility in aging neurons. cAMP/PKA pathway promotes mitochondrial transport in adult Drosophila wing neurons Pathway activation in aged flies suppresses age-related reduction in transport Levels of PKAc and kinesin-1 motor decline during aging Kinesin-1 upregulation is an important output of PKA activation in aged flies
Collapse
Affiliation(s)
- Alessio Vagnoni
- Division of Cell Biology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK; Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, King's College London, London SE5 9RX, UK.
| | - Simon L Bullock
- Division of Cell Biology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
| |
Collapse
|
59
|
Carelli V, La Morgia C, Ross-Cisneros FN, Sadun AA. Optic neuropathies: the tip of the neurodegeneration iceberg. Hum Mol Genet 2018; 26:R139-R150. [PMID: 28977448 PMCID: PMC5886475 DOI: 10.1093/hmg/ddx273] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 07/10/2017] [Indexed: 01/06/2023] Open
Abstract
The optic nerve and the cells that give origin to its 1.2 million axons, the retinal ganglion cells (RGCs), are particularly vulnerable to neurodegeneration related to mitochondrial dysfunction. Optic neuropathies may range from non-syndromic genetic entities, to rare syndromic multisystem diseases with optic atrophy such as mitochondrial encephalomyopathies, to age-related neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease where optic nerve involvement has, until recently, been a relatively overlooked feature. New tools are available to thoroughly investigate optic nerve function, allowing unparalleled access to this part of the central nervous system. Understanding the molecular pathophysiology of RGC neurodegeneration and optic atrophy, is key to broadly understanding the pathogenesis of neurodegenerative disorders, for monitoring their progression in describing the natural history, and ultimately as outcome measures to evaluate therapies. In this review, the different layers, from molecular to anatomical, that may contribute to RGC neurodegeneration and optic atrophy are tackled in an integrated way, considering all relevant players. These include RGC dendrites, cell bodies and axons, the unmyelinated retinal nerve fiber layer and the myelinated post-laminar axons, as well as olygodendrocytes and astrocytes, looked for unconventional functions. Dysfunctional mitochondrial dynamics, transport, homeostatic control of mitobiogenesis and mitophagic removal, as well as specific propensity to apoptosis may target differently cell types and anatomical settings. Ultimately, we can envisage new investigative approaches and therapeutic options that will speed the early diagnosis of neurodegenerative diseases and their cure.
Collapse
Affiliation(s)
- Valerio Carelli
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy.,Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | - Chiara La Morgia
- IRCCS Institute of Neurological Sciences of Bologna, Bellaria Hospital, Bologna, Italy.,Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
| | | | - Alfredo A Sadun
- Doheny Eye Institute, Los Angeles, CA 90033, USA.,Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| |
Collapse
|
60
|
Misgeld T, Schwarz TL. Mitostasis in Neurons: Maintaining Mitochondria in an Extended Cellular Architecture. Neuron 2017; 96:651-666. [PMID: 29096078 DOI: 10.1016/j.neuron.2017.09.055] [Citation(s) in RCA: 321] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 09/25/2017] [Accepted: 09/28/2017] [Indexed: 02/06/2023]
Abstract
Neurons have more extended and complex shapes than other cells and consequently face a greater challenge in distributing and maintaining mitochondria throughout their arbors. Neurons can last a lifetime, but proteins turn over rapidly. Mitochondria, therefore, need constant rejuvenation no matter how far they are from the soma. Axonal transport of mitochondria and mitochondrial fission and fusion contribute to this rejuvenation, but local protein synthesis is also likely. Maintenance of a healthy mitochondrial population also requires the clearance of damaged proteins and organelles. This involves degradation of individual proteins, sequestration in mitochondria-derived vesicles, organelle degradation by mitophagy and macroautophagy, and in some cases transfer to glial cells. Both long-range transport and local processing are thus at work in achieving neuronal mitostasis-the maintenance of an appropriately distributed pool of healthy mitochondria for the duration of a neuron's life. Accordingly, defects in the processes that support mitostasis are significant contributors to neurodegenerative disorders.
Collapse
Affiliation(s)
- Thomas Misgeld
- Technical University of Munich, Institute of Neuronal Cell Biology, Munich, Germany; German Center for Neurodegenerative Diseases, Munich, Germany; Munich Cluster for Systems Neurology, Munich, Germany; Center of Integrated Protein Science, Munich, Germany.
| | - Thomas L Schwarz
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA; F.M. Kirby Neurobiology Center, Children's Hospital, Boston, MA, USA.
| |
Collapse
|
61
|
Ito YA, Di Polo A. Mitochondrial dynamics, transport, and quality control: A bottleneck for retinal ganglion cell viability in optic neuropathies. Mitochondrion 2017; 36:186-192. [PMID: 28866056 DOI: 10.1016/j.mito.2017.08.014] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 08/11/2017] [Accepted: 08/29/2017] [Indexed: 01/03/2023]
Abstract
Retinal ganglion cells, the neurons that selectively die in glaucoma and other optic neuropathies, are endowed with an exceedingly active metabolism and display a particular vulnerability to mitochondrial dysfunction. Mitochondria are exquisitely dynamic organelles that are continually responding to endogenous and environmental cues to readily meet the energy demand of neuronal networks. The highly orchestrated regulation of mitochondrial biogenesis, fusion, fission, transport and degradation is paramount for the maintenance of energy-expensive synapses at RGC dendrites and axon terminals geared for optimal neurotransmission. The present review focuses on the progress made to date on understanding the biology of mitochondrial dynamics and quality control and how dysregulation of these processes can profoundly affect retinal ganglion cell viability and function in optic nerve diseases.
Collapse
Affiliation(s)
- Yoko A Ito
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Department of Neuroscience, Université de Montréal, Montreal, Quebec H2X 1R9, Canada
| | - Adriana Di Polo
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Department of Neuroscience, Université de Montréal, Montreal, Quebec H2X 1R9, Canada.
| |
Collapse
|
62
|
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.
Collapse
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.
| |
Collapse
|
63
|
Konietzny A, Bär J, Mikhaylova M. Dendritic Actin Cytoskeleton: Structure, Functions, and Regulations. Front Cell Neurosci 2017; 11:147. [PMID: 28572759 PMCID: PMC5435805 DOI: 10.3389/fncel.2017.00147] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/05/2017] [Indexed: 12/28/2022] Open
Abstract
Actin is a versatile and ubiquitous cytoskeletal protein that plays a major role in both the establishment and the maintenance of neuronal polarity. For a long time, the most prominent roles that were attributed to actin in neurons were the movement of growth cones, polarized cargo sorting at the axon initial segment, and the dynamic plasticity of dendritic spines, since those compartments contain large accumulations of actin filaments (F-actin) that can be readily visualized using electron- and fluorescence microscopy. With the development of super-resolution microscopy in the past few years, previously unknown structures of the actin cytoskeleton have been uncovered: a periodic lattice consisting of actin and spectrin seems to pervade not only the whole axon, but also dendrites and even the necks of dendritic spines. Apart from that striking feature, patches of F-actin and deep actin filament bundles have been described along the lengths of neurites. So far, research has been focused on the specific roles of actin in the axon, while it is becoming more and more apparent that in the dendrite, actin is not only confined to dendritic spines, but serves many additional and important functions. In this review, we focus on recent developments regarding the role of actin in dendrite morphology, the regulation of actin dynamics by internal and external factors, and the role of F-actin in dendritic protein trafficking.
Collapse
Affiliation(s)
- Anja Konietzny
- DFG Emmy Noether Group 'Neuronal Protein Transport,' Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-EppendorfHamburg, Germany
| | - Julia Bär
- DFG Emmy Noether Group 'Neuronal Protein Transport,' Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-EppendorfHamburg, Germany
| | - Marina Mikhaylova
- DFG Emmy Noether Group 'Neuronal Protein Transport,' Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-EppendorfHamburg, Germany
| |
Collapse
|
64
|
ZBP1 phosphorylation at serine 181 regulates its dendritic transport and the development of dendritic trees of hippocampal neurons. Sci Rep 2017; 7:1876. [PMID: 28500298 PMCID: PMC5431813 DOI: 10.1038/s41598-017-01963-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 04/07/2017] [Indexed: 11/23/2022] Open
Abstract
Local protein synthesis occurs in axons and dendrites of neurons, enabling fast and spatially restricted responses to a dynamically changing extracellular environment. Prior to local translation, mRNA that is to be translated is packed into ribonucleoprotein particles (RNPs) where RNA binding proteins ensure mRNA silencing and provide a link to molecular motors. ZBP1 is a component of RNP transport particles and is known for its role in the local translation of β-actin mRNA. Its binding to mRNA is regulated by tyrosine 396 phosphorylation, and this particular modification was shown to be vital for axonal growth and dendritic branching. Recently, additional phosphorylation of ZBP1 at serine 181 (Ser181) was described in non-neuronal cells. In the present study, we found that ZBP1 is also phosphorylated at Ser181 in neurons in a mammalian/mechanistic target of rapamycin complex 2-, Src kinase-, and mRNA binding-dependent manner. Furthermore, Ser181 ZBP1 phosphorylation was essential for the proper dendritic branching of hippocampal neurons that were cultured in vitro and for the proper ZBP1 dendritic distribution and motility.
Collapse
|
65
|
Lutter M, Khan MZ, Satio K, Davis KC, Kidder IJ, McDaniel L, Darbro BW, Pieper AA, Cui H. The Eating-Disorder Associated HDAC4 A778T Mutation Alters Feeding Behaviors in Female Mice. Biol Psychiatry 2017; 81:770-777. [PMID: 27884425 PMCID: PMC5386818 DOI: 10.1016/j.biopsych.2016.09.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 09/02/2016] [Accepted: 09/26/2016] [Indexed: 12/21/2022]
Abstract
BACKGROUND While eating disorders (EDs) are thought to result from a combination of environmental and psychological stressors superimposed on genetic vulnerability, the neurobiological basis of EDs remains incompletely understood. We recently reported that a rare missense mutation in the gene for the transcriptional repressor histone deacetylase 4 (HDAC4) is associated with the risk of developing an ED in humans. METHODS To understand the biological consequences of this missense mutation, we created transgenic mice carrying this mutation by introducing the alanine to threonine mutation at position 778 of mouse Hdac4 (corresponding to position 786 of the human protein). Bioinformatic analysis to identify Hdac4-regulated genes was performed using available databases. RESULTS Male mice heterozygous for HDAC4A778T did not show any metabolic or behavioral differences. In contrast, female mice heterozygous for HDAC4A778T display several ED-related feeding and behavioral deficits depending on housing condition. Individually housed HDAC4A778T female mice exhibit reduced effortful responding for high-fat diet and compulsive grooming, whereas group-housed female mice display increased weight gain on high-fat diet, reduced behavioral despair, and increased anxiety-like behaviors. Bioinformatic analysis identifies mitochondrial biogenesis including synthesis of glutamate/gamma-aminobutyric acid as a potential transcriptional target of HDAC4A778T activity relevant to the behavioral deficits identified in this new mouse model of disordered eating. CONCLUSIONS The HDAC4A778T mouse line is a novel model of ED-related behaviors and identifies mitochondrial biogenesis as a potential molecular pathway contributing to behavioral deficits.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | - Huxing Cui
- Pharmacology, University of Iowa, Carver College of Medicine, Iowa City, Iowa.
| |
Collapse
|
66
|
Rangaraju V, Tom Dieck S, Schuman EM. Local translation in neuronal compartments: how local is local? EMBO Rep 2017; 18:693-711. [PMID: 28404606 DOI: 10.15252/embr.201744045] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/15/2017] [Accepted: 03/15/2017] [Indexed: 12/18/2022] Open
Abstract
Efficient neuronal function depends on the continued modulation of the local neuronal proteome. Local protein synthesis plays a central role in tuning the neuronal proteome at specific neuronal regions. Various aspects of translation such as the localization of translational machinery, spatial spread of the newly translated proteins, and their site of action are carried out in specialized neuronal subcompartments to result in a localized functional outcome. In this review, we focus on the various aspects of these local translation compartments such as size, biochemical and organelle composition, structural boundaries, and temporal dynamics. We also discuss the apparent absence of definitive components of translation in these local compartments and the emerging state-of-the-art tools that could help dissecting these conundrums in greater detail in the future.
Collapse
Affiliation(s)
- Vidhya Rangaraju
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany
| | | | - Erin M Schuman
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany
| |
Collapse
|
67
|
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.
Collapse
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.
| |
Collapse
|
68
|
Lewis TL, Turi GF, Kwon SK, Losonczy A, Polleux F. Progressive Decrease of Mitochondrial Motility during Maturation of Cortical Axons In Vitro and In Vivo. Curr Biol 2016; 26:2602-2608. [PMID: 27641765 DOI: 10.1016/j.cub.2016.07.064] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 07/21/2016] [Accepted: 07/26/2016] [Indexed: 10/21/2022]
Abstract
The importance of mitochondria for neuronal function is evident by the large number of neurodegenerative diseases that have been associated with a disruption of mitochondrial function or transport (reviewed in [1, 2]). Mitochondria are essential for proper biological function as a result of their ability to produce ATP through oxidative phosphorylation, buffer cytoplasmic calcium, regulate lipid biosynthesis, and trigger apoptosis (reviewed in [2]). Efficient transport of mitochondria is thought to be particularly important in neurons in light of their compartmentalization, length of axonal processes, and high-energy requirements (reviewed in [3]). However, the majority of these results were obtained using short-term, in vitro neuronal culture models, and very little is currently known about mitochondrial dynamics in mature axons of the mammalian CNS in vitro or in vivo. Furthermore, recent evidence has demonstrated that mitochondrial immobilization at specific points along the axon, such as presynaptic boutons, play critical roles in axon morphogenesis [4, 5]. We report that as cortical axons mature, motility of mitochondria (but not other cargoes) is dramatically reduced and this coincides with increased localization to presynaptic sites. We also demonstrate using photo-conversion that in vitro mature axons display surprisingly limited long-range mitochondrial transport. Finally, using in vivo two-photon microscopy in anesthetized or awake-behaving mice, we document for the first time that mitochondrial motility is also remarkably low in distal cortical axons in vivo. These results argue that mitochondrial immobilization and presynaptic localization are important hallmarks of mature CNS axons both in vitro and in vivo.
Collapse
Affiliation(s)
- Tommy L Lewis
- Department of Neuroscience, Columbia University Medical Center, Mortimer B. Zuckerman Mind Brain Behavior Institute, Kavli Institute for Brain Science, 550 West 120(th) Street, 1103 NWC Building, New York, NY 10027, USA
| | - Gergely F Turi
- Department of Neuroscience, Columbia University Medical Center, Mortimer B. Zuckerman Mind Brain Behavior Institute, Kavli Institute for Brain Science, 550 West 120(th) Street, 1103 NWC Building, New York, NY 10027, USA
| | - Seok-Kyu Kwon
- Department of Neuroscience, Columbia University Medical Center, Mortimer B. Zuckerman Mind Brain Behavior Institute, Kavli Institute for Brain Science, 550 West 120(th) Street, 1103 NWC Building, New York, NY 10027, USA
| | - Attila Losonczy
- Department of Neuroscience, Columbia University Medical Center, Mortimer B. Zuckerman Mind Brain Behavior Institute, Kavli Institute for Brain Science, 550 West 120(th) Street, 1103 NWC Building, New York, NY 10027, USA
| | - Franck Polleux
- Department of Neuroscience, Columbia University Medical Center, Mortimer B. Zuckerman Mind Brain Behavior Institute, Kavli Institute for Brain Science, 550 West 120(th) Street, 1103 NWC Building, New York, NY 10027, USA.
| |
Collapse
|
69
|
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.
Collapse
|