201
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Horn A, Van der Meulen JH, Defour A, Hogarth M, Sreetama SC, Reed A, Scheffer L, Chandel NS, Jaiswal JK. Mitochondrial redox signaling enables repair of injured skeletal muscle cells. Sci Signal 2017; 10:eaaj1978. [PMID: 28874604 PMCID: PMC5949579 DOI: 10.1126/scisignal.aaj1978] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Strain and physical trauma to mechanically active cells, such as skeletal muscle myofibers, injures their plasma membranes, and mitochondrial function is required for their repair. We found that mitochondrial function was also needed for plasma membrane repair in myoblasts as well as nonmuscle cells, which depended on mitochondrial uptake of calcium through the mitochondrial calcium uniporter (MCU). Calcium uptake transiently increased the mitochondrial production of reactive oxygen species (ROS), which locally activated the guanosine triphosphatase (GTPase) RhoA, triggering F-actin accumulation at the site of injury and facilitating membrane repair. Blocking mitochondrial calcium uptake or ROS production prevented injury-triggered RhoA activation, actin polymerization, and plasma membrane repair. This repair mechanism was shared between myoblasts, nonmuscle cells, and mature skeletal myofibers. Quenching mitochondrial ROS in myofibers during eccentric exercise ex vivo caused increased damage to myofibers, resulting in a greater loss of muscle force. These results suggest a physiological role for mitochondria in plasma membrane repair in injured cells, a role that highlights a beneficial effect of ROS.
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Affiliation(s)
- Adam Horn
- Children's National Health System, Center for Genetic Medicine Research, 111 Michigan Avenue Northwest, Washington, DC 20010-2970, USA
- Department of Integrative Systems Biology, George Washington University School of Medicine and Health Sciences, Washington, DC 20010-2970, USA
| | - Jack H Van der Meulen
- Children's National Health System, Center for Genetic Medicine Research, 111 Michigan Avenue Northwest, Washington, DC 20010-2970, USA
| | - Aurelia Defour
- Children's National Health System, Center for Genetic Medicine Research, 111 Michigan Avenue Northwest, Washington, DC 20010-2970, USA
| | - Marshall Hogarth
- Children's National Health System, Center for Genetic Medicine Research, 111 Michigan Avenue Northwest, Washington, DC 20010-2970, USA
| | - Sen Chandra Sreetama
- Children's National Health System, Center for Genetic Medicine Research, 111 Michigan Avenue Northwest, Washington, DC 20010-2970, USA
| | - Aaron Reed
- Children's National Health System, Center for Genetic Medicine Research, 111 Michigan Avenue Northwest, Washington, DC 20010-2970, USA
| | - Luana Scheffer
- Children's National Health System, Center for Genetic Medicine Research, 111 Michigan Avenue Northwest, Washington, DC 20010-2970, USA
| | - Navdeep S Chandel
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Jyoti K Jaiswal
- Children's National Health System, Center for Genetic Medicine Research, 111 Michigan Avenue Northwest, Washington, DC 20010-2970, USA.
- Department of Integrative Systems Biology, George Washington University School of Medicine and Health Sciences, Washington, DC 20010-2970, USA
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202
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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.
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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.
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203
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Prior R, Van Helleputte L, Benoy V, Van Den Bosch L. Defective axonal transport: A common pathological mechanism in inherited and acquired peripheral neuropathies. Neurobiol Dis 2017; 105:300-320. [DOI: 10.1016/j.nbd.2017.02.009] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 01/29/2017] [Accepted: 02/20/2017] [Indexed: 12/29/2022] Open
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204
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Vaur P, Brugg B, Mericskay M, Li Z, Schmidt MS, Vivien D, Orset C, Jacotot E, Brenner C, Duplus E. Nicotinamide riboside, a form of vitamin B 3, protects against excitotoxicity-induced axonal degeneration. FASEB J 2017; 31:5440-5452. [PMID: 28842432 DOI: 10.1096/fj.201700221rr] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 07/31/2017] [Indexed: 11/11/2022]
Abstract
NAD+ depletion is a common phenomenon in neurodegenerative pathologies. Excitotoxicity occurs in multiple neurologic disorders and NAD+ was shown to prevent neuronal degeneration in this process through mechanisms that remained to be determined. The activity of nicotinamide riboside (NR) in neuroprotective models and the recent description of extracellular conversion of NAD+ to NR prompted us to probe the effects of NAD+ and NR in protection against excitotoxicity. Here, we show that intracortical administration of NR but not NAD+ reduces brain damage induced by NMDA injection. Using cortical neurons, we found that provision of extracellular NR delays NMDA-induced axonal degeneration (AxD) much more strongly than extracellular NAD+ Moreover, the stronger effect of NR compared to NAD+ depends of axonal stress since in AxD induced by pharmacological inhibition of nicotinamide salvage, both NAD+ and NR prevent neuronal death and AxD in a manner that depends on internalization of NR. Taken together, our findings demonstrate that NR is a better neuroprotective agent than NAD+ in excitotoxicity-induced AxD and that axonal protection involves defending intracellular NAD+ homeostasis.-Vaur, P., Brugg, B., Mericskay, M., Li, Z., Schmidt, M. S., Vivien, D., Orset, C., Jacotot, E., Brenner, C., Duplus, E. Nicotinamide riboside, a form of vitamin B3, protects against excitotoxicity-induced axonal degeneration.
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Affiliation(s)
- Pauline Vaur
- Unité Mixte de Recherche (UMR) Adaptation Biologique et Vieillissement (UMR 8256), Institut Biologie Paris Seine, Centre National de la Recherche Scientifique (CNRS), INSERM, Université Pierre et Marie Curie (UPMC), Sorbonne Universités, Paris, France
| | - Bernard Brugg
- Unité Mixte de Recherche (UMR) Adaptation Biologique et Vieillissement (UMR 8256), Institut Biologie Paris Seine, Centre National de la Recherche Scientifique (CNRS), INSERM, Université Pierre et Marie Curie (UPMC), Sorbonne Universités, Paris, France
| | - Mathias Mericskay
- Unité Mixte de Recherche (UMR) Adaptation Biologique et Vieillissement (UMR 8256), Institut Biologie Paris Seine, Centre National de la Recherche Scientifique (CNRS), INSERM, Université Pierre et Marie Curie (UPMC), Sorbonne Universités, Paris, France.,Unité Signalisation et Physiopathologie Cardiovasculaire, INSERM, Université Paris-Saclay, Université Paris Sud, Châtenay-Malabry, France
| | - Zhenlin Li
- Unité Mixte de Recherche (UMR) Adaptation Biologique et Vieillissement (UMR 8256), Institut Biologie Paris Seine, Centre National de la Recherche Scientifique (CNRS), INSERM, Université Pierre et Marie Curie (UPMC), Sorbonne Universités, Paris, France.,Equipe de Recherche Labellisée (ERL) U1164, INSERM, Université Paris-Saclay, Université Paris Sud, Châtenay-Malabry, France
| | - Mark S Schmidt
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Denis Vivien
- Unité INSERM 1237, GIP Cycéron, Centre Hospitalier Universitaire de Caen, Université Caen Normandie, Caen, France
| | - Cyrille Orset
- Unité INSERM 1237, GIP Cycéron, Centre Hospitalier Universitaire de Caen, Université Caen Normandie, Caen, France
| | - Etienne Jacotot
- Unité Mixte de Recherche (UMR) Adaptation Biologique et Vieillissement (UMR 8256), Institut Biologie Paris Seine, Centre National de la Recherche Scientifique (CNRS), INSERM, Université Pierre et Marie Curie (UPMC), Sorbonne Universités, Paris, France
| | - Charles Brenner
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Eric Duplus
- Unité Mixte de Recherche (UMR) Adaptation Biologique et Vieillissement (UMR 8256), Institut Biologie Paris Seine, Centre National de la Recherche Scientifique (CNRS), INSERM, Université Pierre et Marie Curie (UPMC), Sorbonne Universités, Paris, France;
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205
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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: 158] [Impact Index Per Article: 22.6] [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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206
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Kraft LM, Lackner LL. Mitochondrial anchors: Positioning mitochondria and more. Biochem Biophys Res Commun 2017; 500:2-8. [PMID: 28676393 DOI: 10.1016/j.bbrc.2017.06.193] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 06/30/2017] [Indexed: 01/08/2023]
Abstract
The shape and position of mitochondria are intimately connected to both mitochondrial and cellular function. Mitochondrial anchors play a central role in mitochondrial positioning by exerting spatial, temporal, and contextual control over the cellular position of the organelle. Investigations into the molecular mechanisms of mitochondrial anchoring are still in the early stages, and we are beginning to appreciate the number and variety of anchors that exist. From the insight gained thus far, it is clear that mitochondrial anchoring has functional and physiological consequences that extend beyond mitochondrial positioning to other critical cellular processes.
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Affiliation(s)
- Lauren M Kraft
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Laura L Lackner
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA.
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207
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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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208
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Knowlton WM, Hubert T, Wu Z, Chisholm AD, Jin Y. A Select Subset of Electron Transport Chain Genes Associated with Optic Atrophy Link Mitochondria to Axon Regeneration in Caenorhabditis elegans. Front Neurosci 2017; 11:263. [PMID: 28539870 PMCID: PMC5423972 DOI: 10.3389/fnins.2017.00263] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 04/24/2017] [Indexed: 12/13/2022] Open
Abstract
The role of mitochondria within injured neurons is an area of active interest since these organelles are vital for the production of cellular energy in the form of ATP. Using mechanosensory neurons of the nematode Caenorhabditis elegans to test regeneration after neuronal injury in vivo, we surveyed genes related to mitochondrial function for effects on axon regrowth after laser axotomy. Genes involved in mitochondrial transport, calcium uptake, mitophagy, or fission and fusion were largely dispensable for axon regrowth, with the exception of eat-3/Opa1. Surprisingly, many genes encoding components of the electron transport chain were dispensable for regrowth, except for the iron-sulfur proteins gas-1, nduf-2.2, nduf-7, and isp-1, and the putative oxidoreductase rad-8. In these mutants, axonal development was essentially normal and axons responded normally to injury by forming regenerative growth cones, but were impaired in subsequent axon extension. Overexpression of nduf-2.2 or isp-1 was sufficient to enhance regrowth, suggesting that mitochondrial function is rate-limiting in axon regeneration. Moreover, loss of function in isp-1 reduced the enhanced regeneration caused by either a gain-of-function mutation in the calcium channel EGL-19 or overexpression of the MAP kinase DLK-1. While the cellular function of RAD-8 remains unclear, our genetic analyses place rad-8 in the same pathway as other electron transport genes in axon regeneration. Unexpectedly, rad-8 regrowth defects were suppressed by altered function in the ubiquinone biosynthesis gene clk-1. Furthermore, we found that inhibition of the mitochondrial unfolded protein response via deletion of atfs-1 suppressed the defective regrowth in nduf-2.2 mutants. Together, our data indicate that while axon regeneration is not significantly affected by general dysfunction of cellular respiration, it is sensitive to the proper functioning of a select subset of electron transport chain genes, or to the cellular adaptations used by neurons under conditions of injury.
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Affiliation(s)
- Wendy M Knowlton
- Section of Neurobiology, Division of Biological Sciences, University of CaliforniaSan Diego, CA, USA
| | - Thomas Hubert
- Section of Neurobiology, Division of Biological Sciences, University of CaliforniaSan Diego, CA, USA
| | - Zilu Wu
- Howard Hughes Medical Institute, University of CaliforniaSan Diego, CA, USA
| | - Andrew D Chisholm
- Section of Neurobiology, Division of Biological Sciences, University of CaliforniaSan Diego, CA, USA
| | - Yishi Jin
- Section of Neurobiology, Division of Biological Sciences, University of CaliforniaSan Diego, CA, USA.,Howard Hughes Medical Institute, University of CaliforniaSan Diego, CA, USA.,Department of Cellular and Molecular Medicine, School of Medicine, University of CaliforniaSan Diego, CA, USA
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209
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Hill LJ, Williams AC. Meat Intake and the Dose of Vitamin B 3 - Nicotinamide: Cause of the Causes of Disease Transitions, Health Divides, and Health Futures? Int J Tryptophan Res 2017; 10:1178646917704662. [PMID: 28579801 PMCID: PMC5419340 DOI: 10.1177/1178646917704662] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 03/15/2017] [Indexed: 12/26/2022] Open
Abstract
Meat and vitamin B3 - nicotinamide - intake was high during hunter-gatherer times. Intake then fell and variances increased during and after the Neolithic agricultural revolution. Health, height, and IQ deteriorated. Low dietary doses are buffered by 'welcoming' gut symbionts and tuberculosis that can supply nicotinamide, but this co-evolved homeostatic metagenomic strategy risks dysbioses and impaired resistance to pathogens. Vitamin B3 deficiency may now be common among the poor billions on a low-meat diet. Disease transitions to non-communicable inflammatory disorders (but longer lives) may be driven by positive 'meat transitions'. High doses of nicotinamide lead to reduced regulatory T cells and immune intolerance. Loss of no longer needed symbiotic 'old friends' compounds immunological over-reactivity to cause allergic and auto-immune diseases. Inhibition of nicotinamide adenine dinucleotide consumers and loss of methyl groups or production of toxins may cause cancers, metabolic toxicity, or neurodegeneration. An optimal dosage of vitamin B3 could lead to better health, but such a preventive approach needs more equitable meat distribution. Some people may require personalised doses depending on genetic make-up or, temporarily, when under stress.
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Affiliation(s)
- Lisa J Hill
- Neuroscience and Ophthalmology Research Group, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
| | - Adrian C Williams
- Department of Neurology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
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210
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Lin MY, Cheng XT, Tammineni P, Xie Y, Zhou B, Cai Q, Sheng ZH. Releasing Syntaphilin Removes Stressed Mitochondria from Axons Independent of Mitophagy under Pathophysiological Conditions. Neuron 2017; 94:595-610.e6. [PMID: 28472658 PMCID: PMC5484086 DOI: 10.1016/j.neuron.2017.04.004] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 02/14/2017] [Accepted: 04/03/2017] [Indexed: 01/12/2023]
Abstract
Chronic mitochondrial stress is a central problem associated with neurodegenerative diseases. Early removal of defective mitochondria from axons constitutes a critical step of mitochondrial quality control. Here we investigate axonal mitochondrial response to mild stress in wild-type neurons and chronic mitochondrial defects in Amytrophic Lateral Sclerosis (ALS)- and Alzheimer's disease (AD)-linked neurons. We show that stressed mitochondria are removed from axons triggered by the bulk release of mitochondrial anchoring protein syntaphilin via a new class of mitochondria-derived cargos independent of Parkin, Drp1, and autophagy. Immuno-electron microscopy and super-resolution imaging show the budding of syntaphilin cargos, which then share a ride on late endosomes for transport toward the soma. Releasing syntaphilin is also activated in the early pathological stages of ALS- and AD-linked mutant neurons. Our study provides new mechanistic insights into the maintenance of axonal mitochondrial quality through SNPH-mediated coordination of mitochondrial stress and motility before activation of Parkin-mediated mitophagy. VIDEO ABSTRACT.
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Affiliation(s)
- Mei-Yao Lin
- 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
| | - Xiu-Tang Cheng
- 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
| | - Prasad Tammineni
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Yuxiang Xie
- 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
| | - Bing Zhou
- 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
| | - Qian Cai
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, 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, MD 20892-3706, USA.
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211
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Inman DM, Harun-Or-Rashid M. Metabolic Vulnerability in the Neurodegenerative Disease Glaucoma. Front Neurosci 2017; 11:146. [PMID: 28424571 PMCID: PMC5371671 DOI: 10.3389/fnins.2017.00146] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 03/08/2017] [Indexed: 12/14/2022] Open
Abstract
Axons can be several orders of magnitude longer than neural somas, presenting logistical difficulties in cargo trafficking and structural maintenance. Keeping the axon compartment well supplied with energy also presents a considerable challenge; even seemingly subtle modifications of metabolism can result in functional deficits and degeneration. Axons require a great deal of energy, up to 70% of all energy used by a neuron, just to maintain the resting membrane potential. Axonal energy, in the form of ATP, is generated primarily through oxidative phosphorylation in the mitochondria. In addition, glial cells contribute metabolic intermediates to axons at moments of high activity or according to need. Recent evidence suggests energy disruption is an early contributor to pathology in a wide variety of neurodegenerative disorders characterized by axonopathy. However, the degree to which the energy disruption is intrinsic to the axon vs. associated glia is not clear. This paper will review the role of energy availability and utilization in axon degeneration in glaucoma, a chronic axonopathy of the retinal projection.
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Affiliation(s)
- Denise M Inman
- Department of Pharmaceutical Sciences, Northeast Ohio Medical UniversityRootstown, OH, USA
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212
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Transcriptomic investigation of wound healing and regeneration in the cnidarian Calliactis polypus. Sci Rep 2017; 7:41458. [PMID: 28150733 PMCID: PMC5288695 DOI: 10.1038/srep41458] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 12/19/2016] [Indexed: 12/11/2022] Open
Abstract
Wound healing and regeneration in cnidarian species, a group that forms the sister phylum to Bilateria, remains poorly characterised despite the ability of many cnidarians to rapidly repair injuries, regenerate lost structures, or re-form whole organisms from small populations of somatic cells. Here we present results from a fully replicated RNA-Seq experiment to identify genes that are differentially expressed in the sea anemone Calliactis polypus following catastrophic injury. We find that a large-scale transcriptomic response is established in C. polypus, comprising an abundance of genes involved in tissue patterning, energy dynamics, immunity, cellular communication, and extracellular matrix remodelling. We also identified a substantial proportion of uncharacterised genes that were differentially expressed during regeneration, that appear to be restricted to cnidarians. Overall, our study serves to both identify the role that conserved genes play in eumetazoan wound healing and regeneration, as well as to highlight the lack of information regarding many genes involved in this process. We suggest that functional analysis of the large group of uncharacterised genes found in our study may contribute to better understanding of the regenerative capacity of cnidarians, as well as provide insight into how wound healing and regeneration has evolved in different lineages.
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213
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Xu Y, Chen M, Hu B, Huang R, Hu B. In vivo Imaging of Mitochondrial Transport in Single-Axon Regeneration of Zebrafish Mauthner Cells. Front Cell Neurosci 2017; 11:4. [PMID: 28174522 PMCID: PMC5258718 DOI: 10.3389/fncel.2017.00004] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 01/09/2017] [Indexed: 12/17/2022] Open
Abstract
Mitochondrial transport is essential for neuronal function, but the evidence of connections between mitochondrial transport and axon regeneration in the central nervous system (CNS) of living vertebrates remains limited. Here, we developed a novel model to explore mitochondrial transport in a single Mauthner axon (M axon) of zebrafish with non-invasive in vivo imaging. To confirm the feasibility of using this model, we treated labeled zebrafish with nocodazole and demonstrated that it could disrupt mitochondrial transport. We also used two-photon laser axotomy to precisely axotomize M axons and simultaneously recorded their regeneration and the process of mitochondrial transport in living zebrafish larvae. The findings showed that the injured axons with stronger regenerative capability maintain greater mitochondrial motility. Furthermore, to stimulate axon regeneration, treatment with dibutyryl cyclic adenosine monophosphate (db-cAMP) could also augment mitochondrial motility. Taken together, our results provide new evidence that mitochondrial motility is positively correlated with axon regeneration in the living vertebrate CNS. This promising model will be useful for further studies on the interaction between axon regeneration and mitochondrial dynamics, using various genetic and pharmacological techniques.
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Affiliation(s)
- Yang Xu
- Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, and School of Life Sciences, University of Science and Technology of China Hefei, China
| | - Min Chen
- Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, and School of Life Sciences, University of Science and Technology of China Hefei, China
| | - Bingbing Hu
- Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, and School of Life Sciences, University of Science and Technology of China Hefei, China
| | - Rongchen Huang
- Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, and School of Life Sciences, University of Science and Technology of China Hefei, China
| | - Bing Hu
- Chinese Academy of Sciences Key Laboratory of Brain Function and Disease, and School of Life Sciences, University of Science and Technology of China Hefei, China
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214
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Calcutt NA, Smith DR, Frizzi K, Sabbir MG, Chowdhury SKR, Mixcoatl-Zecuatl T, Saleh A, Muttalib N, Van der Ploeg R, Ochoa J, Gopaul A, Tessler L, Wess J, Jolivalt CG, Fernyhough P. Selective antagonism of muscarinic receptors is neuroprotective in peripheral neuropathy. J Clin Invest 2017; 127:608-622. [PMID: 28094765 DOI: 10.1172/jci88321] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 11/22/2016] [Indexed: 01/29/2023] Open
Abstract
Sensory neurons have the capacity to produce, release, and respond to acetylcholine (ACh), but the functional role of cholinergic systems in adult mammalian peripheral sensory nerves has not been established. Here, we have reported that neurite outgrowth from adult sensory neurons that were maintained under subsaturating neurotrophic factor conditions operates under cholinergic constraint that is mediated by muscarinic receptor-dependent regulation of mitochondrial function via AMPK. Sensory neurons from mice lacking the muscarinic ACh type 1 receptor (M1R) exhibited enhanced neurite outgrowth, confirming the role of M1R in tonic suppression of axonal plasticity. M1R-deficient mice made diabetic with streptozotocin were protected from physiological and structural indices of sensory neuropathy. Pharmacological blockade of M1R using specific or selective antagonists, pirenzepine, VU0255035, or muscarinic toxin 7 (MT7) activated AMPK and overcame diabetes-induced mitochondrial dysfunction in vitro and in vivo. These antimuscarinic drugs prevented or reversed indices of peripheral neuropathy, such as depletion of sensory nerve terminals, thermal hypoalgesia, and nerve conduction slowing in diverse rodent models of diabetes. Pirenzepine and MT7 also prevented peripheral neuropathy induced by the chemotherapeutic agents dichloroacetate and paclitaxel or HIV envelope protein gp120. As a variety of antimuscarinic drugs are approved for clinical use against other conditions, prompt translation of this therapeutic approach to clinical trials is feasible.
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215
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Tedeschi A, Bradke F. Spatial and temporal arrangement of neuronal intrinsic and extrinsic mechanisms controlling axon regeneration. Curr Opin Neurobiol 2016; 42:118-127. [PMID: 28039763 DOI: 10.1016/j.conb.2016.12.005] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 12/07/2016] [Accepted: 12/08/2016] [Indexed: 01/30/2023]
Abstract
Axon regeneration and neuronal tissue repair varies across animal lineages as well as in the mammalian central and peripheral nervous systems. While the peripheral nervous system retains the ability to self-repair, the majority of axons in the adult mammalian central nervous system (CNS) fail to reactivate intrinsic growth programs after injury. Recent findings, however, suggest that long-distance axon regeneration, neuronal circuit assembly and recovery of functions in the adult mammalian CNS are possible. Here, we discuss our current knowledge of the cell signaling pathways and networks controlling axon regeneration. In addition, we outline a number of combinatorial strategies that include among others microtubule-based treatments to foster regeneration and functional connectivity after CNS trauma.
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Affiliation(s)
- Andrea Tedeschi
- German Center for Neurodegenerative Diseases (DZNE), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany.
| | - Frank Bradke
- German Center for Neurodegenerative Diseases (DZNE), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany.
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216
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Cartoni R, Norsworthy MW, Bei F, Wang C, Li S, Zhang Y, Gabel CV, Schwarz TL, He Z. The Mammalian-Specific Protein Armcx1 Regulates Mitochondrial Transport during Axon Regeneration. Neuron 2016; 92:1294-1307. [PMID: 28009275 PMCID: PMC5189716 DOI: 10.1016/j.neuron.2016.10.060] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 08/14/2016] [Accepted: 10/20/2016] [Indexed: 11/29/2022]
Abstract
Mitochondrial transport is crucial for neuronal and axonal physiology. However, whether and how it impacts neuronal injury responses, such as neuronal survival and axon regeneration, remain largely unknown. In an established mouse model with robust axon regeneration, we show that Armcx1, a mammalian-specific gene encoding a mitochondria-localized protein, is upregulated after axotomy in this high regeneration condition. Armcx1 overexpression enhances mitochondrial transport in adult retinal ganglion cells (RGCs). Importantly, Armcx1 also promotes both neuronal survival and axon regeneration after injury, and these effects depend on its mitochondrial localization. Furthermore, Armcx1 knockdown undermines both neuronal survival and axon regeneration in the high regenerative capacity model, further supporting a key role of Armcx1 in regulating neuronal injury responses in the adult central nervous system (CNS). Our findings suggest that Armcx1 controls mitochondrial transport during neuronal repair.
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Affiliation(s)
- Romain Cartoni
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA.
| | - Michael W Norsworthy
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Fengfeng Bei
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Chen Wang
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Siwei Li
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Yiling Zhang
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Christopher V Gabel
- Department of Physiology and Biophysics, Photonics Center, Boston University School of Medicine, Boston, MA 02118, USA
| | - Thomas L Schwarz
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
| | - Zhigang He
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA.
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217
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Affiliation(s)
- Allen Kaasik
- From the Department of Pharmacology, University of Tartu, Tartu, Estonia
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