1
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Nheu D, Petratos S. How does Nogo-A signalling influence mitochondrial function during multiple sclerosis pathogenesis? Neurosci Biobehav Rev 2024; 163:105767. [PMID: 38885889 DOI: 10.1016/j.neubiorev.2024.105767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 05/30/2024] [Accepted: 06/08/2024] [Indexed: 06/20/2024]
Abstract
Multiple sclerosis (MS) is a severe neurological disorder that involves inflammation in the brain, spinal cord and optic nerve with key disabling neuropathological outcomes being axonal damage and demyelination. When degeneration of the axo-glial union occurs, a consequence of inflammatory damage to central nervous system (CNS) myelin, dystrophy and death can lead to large membranous structures from dead oligodendrocytes and degenerative myelin deposited in the extracellular milieu. For the first time, this review covers mitochondrial mechanisms that may be operative during MS-related neurodegenerative changes directly activated during accumulating extracellular deposits of myelin associated inhibitory factors (MAIFs), that include the potent inhibitor of neurite outgrowth, Nogo-A. Axonal damage may occur when Nogo-A binds to and signals through its cognate receptor, NgR1, a multimeric complex, to initially stall axonal transport and limit the delivery of important growth-dependent cargo and subcellular organelles such as mitochondria for metabolic efficiency at sites of axo-glial disintegration as a consequence of inflammation. Metabolic efficiency in axons fails during active demyelination and progressive neurodegeneration, preceded by stalled transport of functional mitochondria to fuel axo-glial integrity.
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Affiliation(s)
- Danica Nheu
- Department of Neuroscience, School of Translational Medicine, Monash University, Prahran, VIC 3004, Australia
| | - Steven Petratos
- Department of Neuroscience, School of Translational Medicine, Monash University, Prahran, VIC 3004, Australia.
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2
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Gallo G. The Axonal Actin Filament Cytoskeleton: Structure, Function, and Relevance to Injury and Degeneration. Mol Neurobiol 2024; 61:5646-5664. [PMID: 38216856 DOI: 10.1007/s12035-023-03879-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 12/13/2023] [Indexed: 01/14/2024]
Abstract
Early investigations of the neuronal actin filament cytoskeleton gave rise to the notion that, although growth cones exhibit high levels of actin filaments, the axon shaft exhibits low levels of actin filaments. With the development of new tools and imaging techniques, the axonal actin filament cytoskeleton has undergone a renaissance and is now an active field of research. This article reviews the current state of knowledge about the actin cytoskeleton of the axon shaft. The best understood forms of actin filament organization along axons are axonal actin patches and a submembranous system of rings that endow the axon with protrusive competency and structural integrity, respectively. Additional forms of actin filament organization along the axon have also been described and their roles are being elucidated. Extracellular signals regulate the axonal actin filament cytoskeleton and our understanding of the signaling mechanisms involved is being elaborated. Finally, recent years have seen advances in our perspective on how the axonal actin cytoskeleton is impacted by, and contributes to, axon injury and degeneration. The work to date has opened new venues and future research will undoubtedly continue to provide a richer understanding of the axonal actin filament cytoskeleton.
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Affiliation(s)
- Gianluca Gallo
- Department of Neural Sciences, Shriners Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 North Broad St, Philadelphia, PA, 19140, USA.
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3
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Gallo G. Neuronal glycolysis: focus on developmental morphogenesis and localized subcellular functions. Commun Integr Biol 2024; 17:2343532. [PMID: 38655369 PMCID: PMC11037282 DOI: 10.1080/19420889.2024.2343532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 02/27/2024] [Indexed: 04/26/2024] Open
Abstract
Glycolysis is a metabolic pathway that directly generates adenosine triphosphate (ATP), provides metabolic intermediates for anabolism, and supports mitochondrial oxidative phosphorylation. This review addresses recent advances in our understanding of the functions of neuronal glycolysis during the development of neuronal morphogenesis, focusing on the emergent concept that neuronal glycolysis serves local subcellular bioenergetic roles in maintaining neuronal function. The current evidence indicates that glycolysis is subcellularly targeted to specific organelles and molecular machinery to locally supply bioenergetic support for defined subcellular mechanisms underlying neuronal morphogenesis (i.e. axon extension, axon retraction and axonal transport). Thus, the concept of glycolysis as a "housekeeping" mechanism in neurons would benefit revision and future work aim to further define its subcellular functions at varied developmental stages.
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Affiliation(s)
- Gianluca Gallo
- Department of Neural Sciences, Shriners Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
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4
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Chouhan D, Gordián Vélez WJ, Struzyna LA, Adewole DO, Cullen ER, Burrell JC, O’Donnell JC, Cullen DK. Generation of contractile forces by three-dimensional bundled axonal tracts in micro-tissue engineered neural networks. Front Mol Neurosci 2024; 17:1346696. [PMID: 38590432 PMCID: PMC10999686 DOI: 10.3389/fnmol.2024.1346696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 02/28/2024] [Indexed: 04/10/2024] Open
Abstract
Axonal extension and retraction are ongoing processes that occur throughout all developmental stages of an organism. The ability of axons to produce mechanical forces internally and respond to externally generated forces is crucial for nervous system development, maintenance, and plasticity. Such axonal mechanobiological phenomena have typically been evaluated in vitro at a single-cell level, but these mechanisms have not been studied when axons are present in a bundled three-dimensional (3D) form like in native tissue. In an attempt to emulate native cortico-cortical interactions under in vitro conditions, we present our approach to utilize previously described micro-tissue engineered neural networks (micro-TENNs). Here, micro-TENNs were comprised of discrete populations of rat cortical neurons that were spanned by 3D bundled axonal tracts and physically integrated with each other. We found that these bundled axonal tracts inherently exhibited an ability to generate contractile forces as the microtissue matured. We therefore utilized this micro-TENN testbed to characterize the intrinsic contractile forces generated by the integrated axonal tracts in the absence of any external force. We found that contractile forces generated by bundled axons were dependent on microtubule stability. Moreover, these intra-axonal contractile forces could simultaneously generate tensile forces to induce so-called axonal "stretch-growth" in different axonal tracts within the same microtissue. The culmination of axonal contraction generally occurred with the fusion of both the neuronal somatic regions along the axonal tracts, therefore perhaps showing the innate tendency of cortical neurons to minimize their wiring distance, a phenomenon also perceived during brain morphogenesis. In future applications, this testbed may be used to investigate mechanisms of neuroanatomical development and those underlying certain neurodevelopmental disorders.
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Affiliation(s)
- Dimple Chouhan
- Department of Neurosurgery, Center for Brain Injury and Repair, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Center for Neurotrauma, Neurodegeneration and Restoration, Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
| | - Wisberty J. Gordián Vélez
- Department of Neurosurgery, Center for Brain Injury and Repair, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Center for Neurotrauma, Neurodegeneration and Restoration, Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, United States
| | - Laura A. Struzyna
- Department of Neurosurgery, Center for Brain Injury and Repair, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Center for Neurotrauma, Neurodegeneration and Restoration, Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, United States
| | - Dayo O. Adewole
- Department of Neurosurgery, Center for Brain Injury and Repair, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Center for Neurotrauma, Neurodegeneration and Restoration, Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, United States
| | - Erin R. Cullen
- Department of Neurosurgery, Center for Brain Injury and Repair, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Center for Neurotrauma, Neurodegeneration and Restoration, Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
| | - Justin C. Burrell
- Department of Neurosurgery, Center for Brain Injury and Repair, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Center for Neurotrauma, Neurodegeneration and Restoration, Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
| | - John C. O’Donnell
- Department of Neurosurgery, Center for Brain Injury and Repair, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Center for Neurotrauma, Neurodegeneration and Restoration, Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
| | - D. Kacy Cullen
- Department of Neurosurgery, Center for Brain Injury and Repair, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Center for Neurotrauma, Neurodegeneration and Restoration, Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, United States
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, United States
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5
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Aydın MŞ, Bay S, Yiğit EN, Özgül C, Oğuz EK, Konuk EY, Ayşit N, Cengiz N, Erdoğan E, Him A, Koçak M, Eroglu E, Öztürk G. Active shrinkage protects neurons following axonal transection. iScience 2023; 26:107715. [PMID: 37701578 PMCID: PMC10493506 DOI: 10.1016/j.isci.2023.107715] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 07/31/2023] [Accepted: 08/22/2023] [Indexed: 09/14/2023] Open
Abstract
Trauma, vascular events, or neurodegenerative processes can lead to axonal injury and eventual transection (axotomy). Neurons can survive axotomy, yet the underlying mechanisms are not fully understood. Excessive water entry into injured neurons poses a particular risk due to swelling and subsequent death. Using in vitro and in vivo neurotrauma model systems based on laser transection and surgical nerve cut, we demonstrated that axotomy triggers actomyosin contraction coupled with calpain activity. As a consequence, neurons shrink acutely to force water out through aquaporin channels preventing swelling and bursting. Inhibiting shrinkage increased the probability of neuronal cell death by about 3-fold. These studies reveal a previously unrecognized cytoprotective response mechanism to neurotrauma and offer a fresh perspective on pathophysiological processes in the nervous system.
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Affiliation(s)
- Mehmet Şerif Aydın
- Regenerative and Restorative Medicine Research Center (REMER), Research Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol University, Istanbul 34810, Türkiye
| | - Sadık Bay
- Regenerative and Restorative Medicine Research Center (REMER), Research Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol University, Istanbul 34810, Türkiye
| | - Esra Nur Yiğit
- Regenerative and Restorative Medicine Research Center (REMER), Research Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol University, Istanbul 34810, Türkiye
| | - Cemil Özgül
- Regenerative and Restorative Medicine Research Center (REMER), Research Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol University, Istanbul 34810, Türkiye
| | - Elif Kaval Oğuz
- Department of Science Education, Faculty of Education, Yüzüncü Yıl University, Van 65080, Türkiye
| | - Elçin Yenidünya Konuk
- Department of Medical Biology, School of Medicine, Bakırçay University, İzmir 35665, Türkiye
| | - Neşe Ayşit
- Regenerative and Restorative Medicine Research Center (REMER), Research Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol University, Istanbul 34810, Türkiye
- Department of Medical Biology and Genetics, School of Medicine, Istanbul Medipol University, Istanbul 34810, Türkiye
| | - Nureddin Cengiz
- Department of Histology and Embryology, School of Medicine, Bandırma Onyedi Eylül University, Bandırma, Balıkesir 10200, Türkiye
| | - Ender Erdoğan
- Department of Histology and Embryology, School of Medicine, Selçuk University, Konya 42130, Türkiye
| | - Aydın Him
- Department of Physiology, School of Medicine, Bolu Abant İzzet Baysal University, Bolu 14030, Türkiye
| | - Mehmet Koçak
- Biostatistics and Bioinformatics Analysis Unit, Research Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol University, Istanbul 34810, Türkiye
- Department of Biostatistics and Medical Informatics, International School of Medicine, Istanbul Medipol University, Istanbul 34810, Türkiye
| | - Emrah Eroglu
- Regenerative and Restorative Medicine Research Center (REMER), Research Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol University, Istanbul 34810, Türkiye
| | - Gürkan Öztürk
- Regenerative and Restorative Medicine Research Center (REMER), Research Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol University, Istanbul 34810, Türkiye
- Department of Physiology, International School of Medicine, Istanbul Medipol University, Istanbul 34810, Türkiye
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6
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Ghose A, Pullarkat P. The role of mechanics in axonal stability and development. Semin Cell Dev Biol 2023; 140:22-34. [PMID: 35786351 PMCID: PMC7615100 DOI: 10.1016/j.semcdb.2022.06.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 06/05/2022] [Accepted: 06/13/2022] [Indexed: 01/28/2023]
Abstract
Much of the focus of neuronal cell biology has been devoted to growth cone guidance, synaptogenesis, synaptic activity, plasticity, etc. The axonal shaft too has received much attention, mainly for its astounding ability to transmit action potentials and the transport of material over long distances. For these functions, the axonal cytoskeleton and membrane have been often assumed to play static structural roles. Recent experiments have changed this view by revealing an ultrastructure much richer in features than previously perceived and one that seems to be maintained at a dynamic steady state. The role of mechanics in this is only beginning to be broadly appreciated and appears to involve passive and active modes of coupling different biopolymer filaments, filament turnover dynamics and membrane biophysics. Axons, being unique cellular processes in terms of high aspect ratios and often extreme lengths, also exhibit unique passive mechanical properties that might have evolved to stabilize them under mechanical stress. In this review, we summarize the experiments that have exposed some of these features. It is our view that axonal mechanics deserves much more attention not only due to its significance in the development and maintenance of the nervous system but also due to the susceptibility of axons to injury and neurodegeneration.
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Affiliation(s)
- Aurnab Ghose
- Indian Institute of Science Education and Research, Pune 411 008, India.
| | - Pramod Pullarkat
- Raman Research Institute, C. V. Raman Avenue, Bengaluru 560 080, India.
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7
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Kedra J, Lin S, Pacheco A, Gallo G, Smith GM. Axotomy Induces Drp1-Dependent Fragmentation of Axonal Mitochondria. Front Mol Neurosci 2021; 14:668670. [PMID: 34149354 PMCID: PMC8209475 DOI: 10.3389/fnmol.2021.668670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 05/07/2021] [Indexed: 02/02/2023] Open
Abstract
It is well established that CNS axons fail to regenerate, undergo retrograde dieback, and form dystrophic growth cones due to both intrinsic and extrinsic factors. We sought to investigate the role of axonal mitochondria in the axonal response to injury. A viral vector (AAV) containing a mitochondrially targeted fluorescent protein (mitoDsRed) as well as fluorescently tagged LC3 (GFP-LC3), an autophagosomal marker, was injected into the primary motor cortex, to label the corticospinal tract (CST), of adult rats. The axons of the CST were then injured by dorsal column lesion at C4-C5. We found that mitochondria in injured CST axons near the injury site are fragmented and fragmentation of mitochondria persists for 2 weeks before returning to pre-injury lengths. Fragmented mitochondria have consistently been shown to be dysfunctional and detrimental to cellular health. Inhibition of Drp1, the GTPase responsible for mitochondrial fission, using a specific pharmacological inhibitor (mDivi-1) blocked fragmentation. Additionally, it was determined that there is increased mitophagy in CST axons following Spinal cord injury (SCI) based on increased colocalization of mitochondria and LC3. In vitro models revealed that mitochondrial divalent ion uptake is necessary for injury-induced mitochondrial fission, as inhibiting the mitochondrial calcium uniporter (MCU) using RU360 prevented injury-induced fission. This phenomenon was also observed in vivo. These studies indicate that following the injury, both in vivo and in vitro, axonal mitochondria undergo increased fission, which may contribute to the lack of regeneration seen in CNS neurons.
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Affiliation(s)
- Joseph Kedra
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Shen Lin
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Almudena Pacheco
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Gianluca Gallo
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States.,Department of Anatomy and Cell Biology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - George M Smith
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States.,Department of Neuroscience, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
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8
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Zhang J, Liu W, Zhang X, Lin S, Yan J, Ye J. Sema3A inhibits axonal regeneration of retinal ganglion cells via ROCK2. Brain Res 2019; 1727:146555. [PMID: 31733191 DOI: 10.1016/j.brainres.2019.146555] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 11/03/2019] [Accepted: 11/12/2019] [Indexed: 01/04/2023]
Abstract
Successful regeneration of injured axons in the adult mammalian central nervous system (CNS) is mainly limited by lesion-induced neuronal apoptosis and the inhibitory environment consisting of numerous extrinsic and intrinsic factors. Semaphorin 3A (Sema3A), a classic axonal guidance cue, contributes to the failure of axonal regeneration and can be neutralized to enhance axonal regeneration. Previous studies have suggested that blockage of rho-associated protein kinase 2 (ROCK2) also exerts a protective effect on the survival and axonal regeneration of retinal ganglion cells (RGC, RGCs) after injury. Yet unresolved question is the interaction between the two factors. We thus evaluated the role of Sema3A and ROCK2 in RGC axonal regeneration. In this study, we first examined the expression of Sema3A and ROCK2 against optic nerve crush in vivo and oxygen-glucose deprivation insult to RGCs in vitro at different time points. Then Sema3A, ROCK2 inhibitor Y-27632, combination of both and phosphate-buffered saline (PBS) only were injected into the vitreous cavity after optic nerve crush at various times in different experiments. In order to assess axonal regeneration, we detected the mRNA levels of small proline-rich protein 1A (Sprr1A) and growth-associated protein 43 (GAP43) by quantitative real time-polymerase chain reaction (RT-qPCR), evaluated visual function by Flash Visual Evoked Potentials (F-VEPs), and checked the protein level of GAP43 by immunofluorescent staining. Our results demonstrated that Sema3A significantly suppressed optic nerve regeneration and this effect can be attenuated via blocking ROCK2. Moreover, Sema3A promoted the phosphorylation of myosin light chain 2 (MLC2) (specific downstream effector of ROCK2 concerning neurite growth). Collectively, Sema3A may negatively regulate axonal regeneration through ROCK2 in RGCs.
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Affiliation(s)
- Jieqiong Zhang
- Department of Ophthalmology, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing 400042, China
| | - Wenyi Liu
- Department of Ophthalmology, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing 400042, China
| | - Xi Zhang
- Department of Ophthalmology, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing 400042, China
| | - Sen Lin
- Department of Ophthalmology, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing 400042, China
| | - Jun Yan
- Department 1, State Key Laboratory of Trauma, Burns and Combined Injury, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing 400042, China.
| | - Jian Ye
- Department of Ophthalmology, Research Institute of Surgery, Daping Hospital, Army Medical University, Chongqing 400042, China.
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9
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Boucher E, Goldin-Blais L, Basiren Q, Mandato CA. Actin dynamics and myosin contractility during plasma membrane repair and restoration: Does one ring really heal them all? CURRENT TOPICS IN MEMBRANES 2019; 84:17-41. [PMID: 31610862 DOI: 10.1016/bs.ctm.2019.07.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In order to survive daily insults, cells have evolved various mechanisms that detect, stabilize and repair damages done to their plasma membrane and cytoskeletal structures. Damage to the PM endangers wounded cells by exposing them to uncontrolled exchanges with the extracellular milieu. The processes and molecular machinery enabling PM repair are therefore at the center of the bulk of the investigations into single-cell repair program. Wounds are repaired by dynamically remodeling the composition and shape of the injured area through exocytosis-mediated release of intracellular membrane components to the wounded area, endocytosis-mediated removal of the injured area, or the shedding of the injury. The wound healing program of Xenopus oocytes and early Drosophila embryos is by contrast, mostly characterized by the rapid formation of a large membrane patch over the wound that eventually fuse with the plasma membrane which restores plasma membrane continuity and lead to the shedding of patch material into the extracellular space. Formation and contraction of actomyosin ring restores normal plasma membrane composition and organizes cytoskeletal repairs. The extend of the contributions of the cytoskeleton to the wound healing program of somatic cells have comparatively received little attention. This review offers a survey of the current knowledge on how actin dynamics, myosin-based contraction and other cytoskeletal structures affects PM and cortical cytoskeleton repair of somatic cells.
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Affiliation(s)
- Eric Boucher
- Department of Anatomy and Cell Biology, Faculty of Medicine, McGill University, Montreal, QC, Canada
| | - Laurence Goldin-Blais
- Department of Anatomy and Cell Biology, Faculty of Medicine, McGill University, Montreal, QC, Canada
| | - Quentin Basiren
- Department of Anatomy and Cell Biology, Faculty of Medicine, McGill University, Montreal, QC, Canada
| | - Craig A Mandato
- Department of Anatomy and Cell Biology, Faculty of Medicine, McGill University, Montreal, QC, Canada.
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10
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Gujar MR, Stricker AM, Lundquist EA. RHO-1 and the Rho GEF RHGF-1 interact with UNC-6/Netrin signaling to regulate growth cone protrusion and microtubule organization in Caenorhabditis elegans. PLoS Genet 2019; 15:e1007960. [PMID: 31233487 PMCID: PMC6611649 DOI: 10.1371/journal.pgen.1007960] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 07/05/2019] [Accepted: 05/31/2019] [Indexed: 01/02/2023] Open
Abstract
UNC-6/Netrin is a conserved axon guidance cue that directs growth cone migrations in the dorsal-ventral axis of C. elegans and in the vertebrate spinal cord. UNC-6/Netrin is expressed in ventral cells, and growth cones migrate ventrally toward or dorsally away from UNC-6/Netrin. Recent studies of growth cone behavior during outgrowth in vivo in C. elegans have led to a polarity/protrusion model in directed growth cone migration away from UNC-6/Netrin. In this model, UNC-6/Netrin first polarizes the growth cone via the UNC-5 receptor, leading to dorsally biased protrusion and F-actin accumulation. UNC-6/Netrin then regulates protrusion based on this polarity. The receptor UNC-40/DCC drives protrusion dorsally, away from the UNC-6/Netrin source, and the UNC-5 receptor inhibits protrusion ventrally, near the UNC-6/Netrin source, resulting in dorsal migration. UNC-5 inhibits protrusion in part by excluding microtubules from the growth cone, which are pro-protrusive. Here we report that the RHO-1/RhoA GTPase and its activator GEF RHGF-1 inhibit growth cone protrusion and MT accumulation in growth cones, similar to UNC-5. However, growth cone polarity of protrusion and F-actin were unaffected by RHO-1 and RHGF-1. Thus, RHO-1 signaling acts specifically as a negative regulator of protrusion and MT accumulation, and not polarity. Genetic interactions are consistent with RHO-1 and RHGF-1 acting with UNC-5, as well as with a parallel pathway, to regulate protrusion. The cytoskeletal interacting molecule UNC-33/CRMP was required for RHO-1 activity to inhibit MT accumulation, suggesting that UNC-33/CRMP might act downstream of RHO-1. In sum, these studies describe a new role of RHO-1 and RHGF-1 in regulation of growth cone protrusion by UNC-6/Netrin.
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Affiliation(s)
- Mahekta R. Gujar
- Department of Molecular Biosciences, Program in Molecular, Cellular, and Developmental Biology, University of Kansas, Lawrence, KS, United States of America
| | - Aubrie M. Stricker
- Department of Molecular Biosciences, Program in Molecular, Cellular, and Developmental Biology, University of Kansas, Lawrence, KS, United States of America
| | - Erik A. Lundquist
- Department of Molecular Biosciences, Program in Molecular, Cellular, and Developmental Biology, University of Kansas, Lawrence, KS, United States of America
- * E-mail:
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11
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Shao X, You R, Hui TH, Fang C, Gong Z, Yan Z, Chang RCC, Shenoy VB, Lin Y. Tension- and Adhesion-Regulated Retraction of Injured Axons. Biophys J 2019; 117:193-202. [PMID: 31278003 DOI: 10.1016/j.bpj.2019.06.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 05/27/2019] [Accepted: 06/14/2019] [Indexed: 12/16/2022] Open
Abstract
Damage-induced retraction of axons during traumatic brain injury is believed to play a key role in the disintegration of the neural network and to eventually lead to severe symptoms such as permanent memory loss and emotional disturbances. However, fundamental questions such as how axon retraction progresses and what physical factors govern this process still remain unclear. Here, we report a combined experimental and modeling study to address these questions. Specifically, a sharp atomic force microscope probe was used to transect axons and trigger their retraction in a precisely controlled manner. Interestingly, we showed that the retracting motion of a well-developed axon can be arrested by strong cell-substrate attachment. However, axon retraction was found to be retriggered if a second transection was conducted, albeit with a lower shrinking amplitude. Furthermore, disruption of the actin cytoskeleton or cell-substrate adhesion significantly altered the retracting dynamics of injured axons. Finally, a mathematical model was developed to explain the observed injury response of neural cells in which the retracting motion was assumed to be driven by the pre-tension in the axon and progress against neuron-substrate adhesion as well as the viscous resistance of the cell. Using realistic parameters, model predictions were found to be in good agreement with our observations under a variety of experimental conditions. By revealing the essential physics behind traumatic axon retraction, findings here could provide insights on the development of treatment strategies for axonal injury as well as its possible interplay with other neurodegenerative diseases.
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Affiliation(s)
- Xueying Shao
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China; HKU-Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong, China
| | - Ran You
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Tsz Hin Hui
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China; HKU-Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong, China
| | - Chao Fang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China; HKU-Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong, China
| | - Ze Gong
- Center for Engineering Mechanobiology and Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Zishen Yan
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China; HKU-Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong, China
| | - Raymond Chuen Chung Chang
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Vivek B Shenoy
- Center for Engineering Mechanobiology and Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania.
| | - Yuan Lin
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China; HKU-Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong, China.
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12
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Burger J, van Vliet N, van Heijningen P, Kumra H, Kremers GJ, Alves M, van Cappellen G, Yanagisawa H, Reinhardt DP, Kanaar R, van der Pluijm I, Essers J. Fibulin-4 deficiency differentially affects cytoskeleton structure and dynamics as well as TGFβ signaling. Cell Signal 2019; 58:65-78. [DOI: 10.1016/j.cellsig.2019.02.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 02/28/2019] [Accepted: 02/28/2019] [Indexed: 12/27/2022]
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13
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Characterization of neurite dystrophy after trauma by high speed structured illumination microscopy and lattice light sheet microscopy. J Neurosci Methods 2018; 312:154-161. [PMID: 30529411 DOI: 10.1016/j.jneumeth.2018.12.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 12/04/2018] [Accepted: 12/05/2018] [Indexed: 12/27/2022]
Abstract
BACKGROUND Unbiased screening studies have repeatedly identified actin-related proteins as one of the families of proteins most influenced by neurotrauma. Nevertheless, the status quo model of cytoskeletal reorganization after neurotrauma excludes actin and incorporates only changes in microtubules and intermediate filaments. Actin is excluded in part because it is difficult to image with conventional techniques. However, recent innovations in fluorescent microscopy provide an opportunity to image the actin cytoskeleton at super-resolution resolution in living cells. This study applied these innovations to an in vitro model of neurotrauma. NEW METHOD New methods are introduced for traumatizing neurons before imaging them with high speed structured illumination microscopy or lattice light sheet microscopy. Also, methods for analyzing structured illumination microscopy images to quantify post-traumatic neurite dystrophy are presented. RESULTS Human induced pluripotent stem cell-derived neurons exhibited actin organization typical of immature neurons. Neurite dystrophy increased after trauma but was not influenced by jasplakinolide treatment. The F-actin content of dystrophies varied greatly from one dystrophy to another. COMPARISON WITH EXISTING METHODS In contrast to fixation dependent methods, these methods capture the evolution of the actin cytoskeleton over time in a living cell. In contrast to prior methods based on counting dystrophies, this quantification scheme parameterizes the severity of a given dystrophy as it evolves from a local swelling to an almost-perfect spheroid that threatens to transect the neurite. CONCLUSIONS These methods can be used to investigate genetic factors and therapeutic interventions that modulate the course of neurite dystrophy after trauma.
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14
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Costa AR, Pinto-Costa R, Sousa SC, Sousa MM. The Regulation of Axon Diameter: From Axonal Circumferential Contractility to Activity-Dependent Axon Swelling. Front Mol Neurosci 2018; 11:319. [PMID: 30233318 PMCID: PMC6131297 DOI: 10.3389/fnmol.2018.00319] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 08/17/2018] [Indexed: 01/08/2023] Open
Abstract
In the adult nervous system axon caliber varies widely amongst different tracts. When considering a given axon, its diameter can further fluctuate in space and time, according to processes including the distribution of organelles and activity-dependent mechanisms. In addition, evidence is emerging supporting that in axons circumferential tension/contractility is present. Axonal diameter is generically regarded as being regulated by neurofilaments. When neurofilaments are absent or low, microtubule-dependent mechanisms can also contribute to the regulation of axon caliber. Despite this knowledge, the fine-tune mechanisms controlling diameter and circumferential tension throughout the lifetime of an axon, remain largely elusive. Recent data supports the role of the actin-spectrin-based membrane periodic skeleton and of non-muscle myosin II in the control of axon diameter. However, the cytoskeletal arrangement that underlies circumferential axonal contraction and expansion is still to be discovered. Here, we discuss in a critical viewpoint the existing knowledge on the regulation of axon diameter, with a specific focus on the possible role played by the axonal actin cytoskeleton.
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Affiliation(s)
- Ana Rita Costa
- Nerve Regeneration Group, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, University of Porto, Porto, Portugal
| | - Rita Pinto-Costa
- Nerve Regeneration Group, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, University of Porto, Porto, Portugal.,Instituto de Ciências Biomédicas Abel Salazar (ICBAS), University of Porto, Porto, Portugal
| | - Sara Castro Sousa
- Nerve Regeneration Group, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, University of Porto, Porto, Portugal
| | - Mónica Mendes Sousa
- Nerve Regeneration Group, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, University of Porto, Porto, Portugal
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15
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Mutalik SP, Joseph J, Pullarkat PA, Ghose A. Cytoskeletal Mechanisms of Axonal Contractility. Biophys J 2018; 115:713-724. [PMID: 30054033 DOI: 10.1016/j.bpj.2018.07.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 04/13/2018] [Accepted: 07/06/2018] [Indexed: 11/18/2022] Open
Abstract
Mechanotransduction is likely to be an important mechanism of signaling in thin, elongated cells such as neurons. Maintenance of prestress or rest tension may facilitate mechanotransduction in these cells. In recent years, functional roles for mechanical tension in neuronal development and physiology are beginning to emerge, but the cellular mechanisms regulating neurite tension remain poorly understood. Active contraction of neurites is a potential mechanism of tension regulation. In this study, we have explored cytoskeletal mechanisms mediating active contractility of neuronal axons. We have developed a simple assay in which we evaluate contraction of curved axons upon trypsin-mediated detachment. We show that curved axons undergo contraction and straighten upon deadhesion. Axonal straightening was found to be actively driven by actomyosin contractility, whereas microtubules may subserve a secondary role. We find that although axons show a monotonous decrease in length upon contraction, subcellularly, the cytoskeleton shows a heterogeneous contractile response. Further, using an assay for spontaneous development of tension without trypsin-induced deadhesion, we show that axons are intrinsically contractile. These experiments, using novel experimental approaches, implicate the axonal cytoskeleton in tension homeostasis. Our data suggest that although globally, the axon behaves as a mechanical continuum, locally, the cytoskeleton is remodeled heterogeneously.
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Affiliation(s)
- Sampada P Mutalik
- Indian Institute of Science Education and Research Pune, Pune, Maharashtra, India
| | - Joby Joseph
- Center for Neural and Cognitive Sciences, University of Hyderabad, Hyderabad, Telangana, India
| | | | - Aurnab Ghose
- Indian Institute of Science Education and Research Pune, Pune, Maharashtra, India.
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16
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Abstract
During the process of neurogenesis, the stem cell committed to the neuronal cell fate starts a series of molecular and morphological changes. The understanding of the physio-pathology of mechanisms controlling the molecular and morphological changes occurring during neuronal differentiation is fundamental to the development of effective therapies for many neurologic diseases. Unfortunately, our knowledge of the biological events occurring in the cell during neuronal differentiation is still poor. In this study, we focus preliminarily on the relevance of the cytoskeletal rearrangements, which earlier drive the morphology of the neuronal precursors, and later the migrating/mature neurons. In fact, neuritogenesis, neurite branching, outgrowth and retraction are seminal to the development of a fully functional nervous system. With this in mind, we highlight the importance of iPSC technology to study the processes of cytoskeletal-driven morphological changes during neuronal differentiation.
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17
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Mechanism of Axonal Contractility in Embryonic Drosophila Motor Neurons In Vivo. Biophys J 2017; 111:1519-1527. [PMID: 27705774 PMCID: PMC5052456 DOI: 10.1016/j.bpj.2016.08.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 08/15/2016] [Accepted: 08/18/2016] [Indexed: 11/24/2022] Open
Abstract
Several in vitro and limited in vivo experiments have shown that neurons maintain a rest tension along their axons intrinsically. They grow in response to stretch but contract in response to loss of tension. This contraction eventually leads to the restoration of the rest tension in axons. However, the mechanism by which axons maintain tension in vivo remains elusive. The objective of this work is to elucidate the key cytoskeletal components responsible for generating tension in axons. Toward this goal, in vivo experiments were conducted on single axons of embryonic Drosophila motor neurons in the presence of various drugs. Each axon was slackened mechanically by bringing the neuromuscular junction toward the central nervous system multiple times. In the absence of any drug, axons shortened and restored the straight configuration within 2–4 min of slackening. The total shortening was ∼40% of the original length. The recovery rate in each cycle, but not the recovery magnitude, was dependent on the axon’s prior contraction history. For example, the contraction time of a previously slackened axon may be twice its first-time contraction. This recovery was significantly hampered with the depletion of ATP, inhibition of myosin motors, and disruption of actin filaments. The disruption of microtubules did not affect the recovery magnitude, but, on the contrary, led to an enhanced recovery rate compared to control cases. These results suggest that the actomyosin machinery is the major active element in axonal contraction, whereas microtubules contribute as resistive/dissipative elements.
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18
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Wang J, Zarbin M, Sugino I, Whitehead I, Townes-Anderson E. RhoA Signaling and Synaptic Damage Occur Within Hours in a Live Pig Model of CNS Injury, Retinal Detachment. Invest Ophthalmol Vis Sci 2017; 57:3892-906. [PMID: 27472075 PMCID: PMC4974026 DOI: 10.1167/iovs.16-19447] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
PURPOSE The RhoA pathway is activated after retinal injury. However, the time of onset and consequences of activation are unknown in vivo. Based on in vitro studies we focused on a period 2 hours after retinal detachment, in pig, an animal whose retina is holangiotic and contains cones. METHODS Under anesthesia, retinal detachments were created by subretinal injection of a balanced salt solution. Two hours later, animals were sacrificed and enucleated for GTPase activity assays and quantitative Western blot and confocal microscopy analyses. RESULTS RhoA activity with detachment was increased 1.5-fold compared to that in normal eyes or in eyes that had undergone vitrectomy only. Increased phosphorylation of myosin light chain, a RhoA effector, also occurred. By 2 hours, rod cells had retracted their terminals toward their cell bodies, disrupting the photoreceptor-to-bipolar synapse and producing significant numbers of spherules with SV2 immunolabel in the outer nuclear layer of the retina. In eyes with detachment, distant retina that remained attached also showed significant increases in RhoA activity and synaptic disjunction. Increases in RAC1 activity and glial fibrillary acidic protein (GFAP) were not specific for detachment, and sprouting of bipolar dendrites, reported for longer detachments, was not seen. The RhoA kinase inhibitor Y27632 significantly reduced axonal retraction by rod cells. CONCLUSIONS Activation of the RhoA pathway occurs quickly after injury and promotes synaptic damage that can be controlled by RhoA kinase inhibition. We suggest that retinal detachment joins the list of central nervous system injuries, such as stroke and spinal cord injury, that should be considered for rapid therapeutic intervention.
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Affiliation(s)
- Jianfeng Wang
- Department of Pharmacology Physiology, and Neuroscience, New Jersey Medical School-Rutgers Biomedical Health Sciences, Rutgers University, Newark, New Jersey, United States
| | - Marco Zarbin
- Institute of Ophthalmology and Visual Science, New Jersey Medical School-Rutgers Biomedical Health Sciences, Rutgers University, Newark, New Jersey, United States
| | - Ilene Sugino
- Institute of Ophthalmology and Visual Science, New Jersey Medical School-Rutgers Biomedical Health Sciences, Rutgers University, Newark, New Jersey, United States
| | - Ian Whitehead
- Department of Microbiology, Biochemistry, and Medical Genetics, New Jersey Medical School-Rutgers Biomedical Health Sciences, Rutgers University, Newark, New Jersey, United States
| | - Ellen Townes-Anderson
- Department of Pharmacology Physiology, and Neuroscience, New Jersey Medical School-Rutgers Biomedical Health Sciences, Rutgers University, Newark, New Jersey, United States
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19
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Hu J, Zhang G, Rodemer W, Jin LQ, Shifman M, Selzer ME. The role of RhoA in retrograde neuronal death and axon regeneration after spinal cord injury. Neurobiol Dis 2016; 98:25-35. [PMID: 27888137 DOI: 10.1016/j.nbd.2016.11.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 10/24/2016] [Accepted: 11/20/2016] [Indexed: 01/13/2023] Open
Abstract
Paralysis following spinal cord injury (SCI) is due to interruption of axons and their failure to regenerate. It has been suggested that the small GTPase RhoA may be an intracellular signaling convergence point for several types of growth-inhibiting extracellular molecules. Even if this is true in vitro, it is not clear from studies in mammalian SCI, whether the effects of RhoA manipulations on axon growth in vivo are due to a RhoA-mediated inhibition of true regeneration or only of collateral sprouting from spared axons, since work on SCI generally is performed with partial injury models. RhoA also has been implicated in local neuronal apoptosis after SCI, but whether this reflects an effect on axotomy-induced cell death or an effect on other pathological mechanisms is not known. In order to resolve these ambiguities, we studied the effects of RhoA knockdown in the sea lamprey central nervous system (CNS), where after complete spinal cord transection (TX), robust but incomplete regeneration of large axons belonging to individually identified reticulospinal (RS) neurons occurs, and where some RS neurons show unambiguous delayed retrograde apoptosis after axotomy. RhoA protein was detected in neurons and axons of the lamprey brain and spinal cord, and its expression was increased post-TX. Knockdown of RhoA in vivo by retrogradely-delivered morpholino antisense oligonucleotides (MOs) to the RS neurons significantly reduced retrograde apoptosis signaling in identified RS neurons post-SCI, as indicated by Fluorochrome Labeled Inhibitor of Caspases (FLICA) in brain wholemounts. In individual RS neurons, the reduction of caspase activation by RhoA knockdown began at 2weeks post-TX and was still seen at 8weeks. RhoA knockdown slowed axon retraction and possibly increased early axon regeneration in the proximal stump. The number of axons regenerating beyond the lesion more than 5mm at 10weeks post-TX also was increased. Thus RhoA knockdown both enhanced true axon regeneration and inhibited retrograde apoptosis signaling after SCI.
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Affiliation(s)
- Jianli Hu
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA 19140, USA
| | - Guixin Zhang
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA 19140, USA
| | - William Rodemer
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA 19140, USA
| | - Li-Qing Jin
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA 19140, USA
| | - Michael Shifman
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA 19140, USA
| | - Michael E Selzer
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA 19140, USA; Dept. of Neurology, Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA 19140, USA.
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20
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Rodriguez-Pallares J, Rodriguez-Perez AI, Muñoz A, Parga JA, Toledo-Aral JJ, Labandeira-Garcia JL. Effects of Rho Kinase Inhibitors on Grafts of Dopaminergic Cell Precursors in a Rat Model of Parkinson's Disease. Stem Cells Transl Med 2016; 5:804-15. [PMID: 27075764 DOI: 10.5966/sctm.2015-0182] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 01/25/2016] [Indexed: 01/29/2023] Open
Abstract
UNLABELLED In models of Parkinson's disease (PD), Rho kinase (ROCK) inhibitors have antiapoptotic and axon-stabilizing effects on damaged neurons, decrease the neuroinflammatory response, and protect against dopaminergic neuron death and axonal retraction. ROCK inhibitors have also shown protective effects against apoptosis induced by handling and dissociation of several types of stem cells. However, the effect of ROCK inhibitors on dopaminergic cell grafts has not been investigated. In the present study, treatment of dopaminergic cell suspension with ROCK inhibitors yielded significant decreases in the number of surviving dopaminergic neurons, in the density of graft-derived dopaminergic fibers, and in graft vascularization. Dopaminergic neuron death also markedly increased in primary mesencephalic cultures when the cell suspension was treated with ROCK inhibitors before plating, which suggests that decreased angiogenesis is not the only factor leading to cell death in grafts. Interestingly, treatment of the host 6-hydroxydopamine-lesioned rats with ROCK inhibitors induced a slight, nonsignificant increase in the number of surviving neurons, as well as marked increases in the density of graft-derived dopaminergic fibers and the size of the striatal reinnervated area. The study findings discourage treatment of cell suspensions before grafting. However, treatment of the host induces a marked increase in graft-derived striatal reinnervation. Because ROCK inhibitors have also exerted neuroprotective effects in several models of PD, treatment of the host with ROCK inhibitors, currently used against vascular diseases in clinical practice, before and after grafting may be a useful adjuvant to cell therapy in PD. SIGNIFICANCE Cell-replacement therapy is one promising therapy for Parkinson's disease (PD). However, many questions must be addressed before widespread application. Rho kinase (ROCK) inhibitors have been used in a variety of applications associated with stem cell research and may be an excellent strategy for improving survival of grafted neurons and graft-derived dopaminergic innervation. The present results discourage the treatment of suspensions of dopaminergic precursors with ROCK inhibitors in the pregrafting period. However, treatment of the host (patients with PD) with ROCK inhibitors, currently used against vascular diseases, may be a useful adjuvant to cell therapy in PD.
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Affiliation(s)
- Jannette Rodriguez-Pallares
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, Center for Research in Molecular Medicine and Chronic Diseases, University of Santiago de Compostela, Santiago de Compostela, Spain Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Ana I Rodriguez-Perez
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, Center for Research in Molecular Medicine and Chronic Diseases, University of Santiago de Compostela, Santiago de Compostela, Spain Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Ana Muñoz
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, Center for Research in Molecular Medicine and Chronic Diseases, University of Santiago de Compostela, Santiago de Compostela, Spain Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Juan A Parga
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, Center for Research in Molecular Medicine and Chronic Diseases, University of Santiago de Compostela, Santiago de Compostela, Spain Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Juan J Toledo-Aral
- Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain Instituto de Biomedicina de Sevilla (IBIS), Department de Fisiología Médica y Biofísica, Hospital Virgen del Rocío/Spanish National Research Council (CSIC)/Universidad de Sevilla, Seville, Spain
| | - Jose L Labandeira-Garcia
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, Center for Research in Molecular Medicine and Chronic Diseases, University of Santiago de Compostela, Santiago de Compostela, Spain Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
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21
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Ketschek A, Spillane M, Dun XP, Hardy H, Chilton J, Gallo G. Drebrin coordinates the actin and microtubule cytoskeleton during the initiation of axon collateral branches. Dev Neurobiol 2016; 76:1092-110. [PMID: 26731339 DOI: 10.1002/dneu.22377] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 12/07/2015] [Accepted: 01/01/2016] [Indexed: 11/10/2022]
Abstract
Drebrin is a cytoskeleton-associated protein which can interact with both actin filaments and the tips of microtubules. Its roles have been studied mostly in dendrites, and the functions of drebrin in axons are less well understood. In this study, we analyzed the role of drebrin, through shRNA-mediated depletion and overexpression, in the collateral branching of chicken embryonic sensory axons. We report that drebrin promotes the formation of axonal filopodia and collateral branches in vivo and in vitro. Live imaging of cytoskeletal dynamics revealed that drebrin promotes the formation of filopodia from precursor structures termed axonal actin patches. Endogenous drebrin localizes to actin patches and depletion studies indicate that drebrin contributes to the development of patches. In filopodia, endogenous drebrin localizes to the proximal portion of the filopodium. Drebrin was found to promote the stability of axonal filopodia and the entry of microtubule plus tips into axonal filopodia. The effects of drebrin on the stabilization of filopodia are independent of its effects on promoting microtubule targeting to filopodia. Inhibition of myosin II induces a redistribution of endogenous drebrin distally into filopodia, and further increases branching in drebrin overexpressing neurons. Finally, a 30 min treatment with the branch-inducing signal nerve growth factor increases the levels of axonal drebrin. This study determines the specific roles of drebrin in the regulation of the axonal cytoskeleton, and provides evidence that drebrin contributes to the coordination of the actin and microtubule cytoskeleton during the initial stages of axon branching. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 76: 1092-1110, 2016.
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Affiliation(s)
- Andrea Ketschek
- Department of Anatomy and Cell Biology, Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, 3500 N. Broad St, Philadelphia, Pennsylvania, 19140
| | - Mirela Spillane
- Department of Anatomy and Cell Biology, Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, 3500 N. Broad St, Philadelphia, Pennsylvania, 19140
| | - Xin-Peng Dun
- Peninsula Schools of Medicine and Dentistry, University of Plymouth, Plymouth Science Park, Research Way, Plymouth, PL6 8BU, United Kingdom
| | - Holly Hardy
- RILD Building, University of Exeter Medical School, Wellcome Wolfson Medical Research Centre, Barrack Road, Exeter, EX2 5DW, United Kingdom
| | - John Chilton
- RILD Building, University of Exeter Medical School, Wellcome Wolfson Medical Research Centre, Barrack Road, Exeter, EX2 5DW, United Kingdom
| | - Gianluca Gallo
- Department of Anatomy and Cell Biology, Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, 3500 N. Broad St, Philadelphia, Pennsylvania, 19140
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22
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Jacob RS, George E, Singh PK, Salot S, Anoop A, Jha NN, Sen S, Maji SK. Cell Adhesion on Amyloid Fibrils Lacking Integrin Recognition Motif. J Biol Chem 2016; 291:5278-98. [PMID: 26742841 DOI: 10.1074/jbc.m115.678177] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Indexed: 12/23/2022] Open
Abstract
Amyloids are highly ordered, cross-β-sheet-rich protein/peptide aggregates associated with both human diseases and native functions. Given the well established ability of amyloids in interacting with cell membranes, we hypothesize that amyloids can serve as universal cell-adhesive substrates. Here, we show that, similar to the extracellular matrix protein collagen, amyloids of various proteins/peptides support attachment and spreading of cells via robust stimulation of integrin expression and formation of integrin-based focal adhesions. Additionally, amyloid fibrils are also capable of immobilizing non-adherent red blood cells through charge-based interactions. Together, our results indicate that both active and passive mechanisms contribute to adhesion on amyloid fibrils. The present data may delineate the functional aspect of cell adhesion on amyloids by various organisms and its involvement in human diseases. Our results also raise the exciting possibility that cell adhesivity might be a generic property of amyloids.
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Affiliation(s)
- Reeba S Jacob
- From the Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India
| | - Edna George
- From the Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India
| | - Pradeep K Singh
- From the Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India
| | - Shimul Salot
- From the Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India
| | - Arunagiri Anoop
- From the Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India
| | - Narendra Nath Jha
- From the Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India
| | - Shamik Sen
- From the Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India
| | - Samir K Maji
- From the Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India
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23
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Bober BG, Love JM, Horton SM, Sitnova M, Shahamatdar S, Kannan A, Shah SB. Actin-myosin network influences morphological response of neuronal cells to altered osmolarity. Cytoskeleton (Hoboken) 2015; 72:193-206. [DOI: 10.1002/cm.21219] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 03/11/2015] [Accepted: 03/17/2015] [Indexed: 12/17/2022]
Affiliation(s)
- Brian G. Bober
- Department of Bioengineering; University of California, San Diego; La Jolla California
| | - James M. Love
- Fischell Department of Bioengineering; University of Maryland; College Park Maryland
| | - Steven M. Horton
- Department of Orthopaedic Surgery; University of California, San Diego; La Jolla California
| | - Mariya Sitnova
- Fischell Department of Bioengineering; University of Maryland; College Park Maryland
| | - Sina Shahamatdar
- Fischell Department of Bioengineering; University of Maryland; College Park Maryland
| | - Ajay Kannan
- Fischell Department of Bioengineering; University of Maryland; College Park Maryland
| | - Sameer B. Shah
- Department of Bioengineering; University of California, San Diego; La Jolla California
- Fischell Department of Bioengineering; University of Maryland; College Park Maryland
- Department of Orthopaedic Surgery; University of California, San Diego; La Jolla California
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24
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Challagundla M, Koch JC, Ribas VT, Michel U, Kügler S, Ostendorf T, Bradke F, Müller HW, Bähr M, Lingor P. AAV-mediated expression of BAG1 and ROCK2-shRNA promote neuronal survival and axonal sprouting in a rat model of rubrospinal tract injury. J Neurochem 2015; 134:261-75. [DOI: 10.1111/jnc.13102] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Revised: 02/14/2015] [Accepted: 03/06/2015] [Indexed: 11/27/2022]
Affiliation(s)
| | - Jan Christoph Koch
- Department of Neurology; University Medicine Göttingen; Göttingen Germany
| | | | - Uwe Michel
- Department of Neurology; University Medicine Göttingen; Göttingen Germany
| | - Sebastian Kügler
- Department of Neurology; University Medicine Göttingen; Göttingen Germany
| | - Thomas Ostendorf
- Department of Neurology; University Medicine Göttingen; Göttingen Germany
| | - Frank Bradke
- German Center for Neurodegenerative Diseases (DZNE); Bonn Germany
| | - Hans Werner Müller
- Department of Neurology; Molecular Neurobiology Laboratory; Heinrich-Heine-University Medical Center Düsseldorf; Düsseldorf Germany
| | - Mathias Bähr
- Department of Neurology; University Medicine Göttingen; Göttingen Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB); Göttingen Germany
| | - Paul Lingor
- Department of Neurology; University Medicine Göttingen; Göttingen Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB); Göttingen Germany
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25
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Labandeira-Garcia JL, Rodríguez-Perez AI, Villar-Cheda B, Borrajo A, Dominguez-Meijide A, Guerra MJ. Rho Kinase and Dopaminergic Degeneration. Neuroscientist 2014; 21:616-29. [DOI: 10.1177/1073858414554954] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The small GTP-binding protein Rho plays an important role in several cellular functions. RhoA, which is a member of the Rho family, initiates cellular processes that act on its direct downstream effector Rho-associated kinase (ROCK). ROCK inhibition protects against dopaminergic cell death induced by dopaminergic neurotoxins. It has been suggested that ROCK inhibition activates neuroprotective survival cascades in dopaminergic neurons. Axon-stabilizing effects in damaged neurons may represent another mechanism of neuroprotection of dopaminergic neurons by ROCK inhibition. However, it has been shown that microglial cells play a crucial role in neuroprotection by ROCK inhibition and that activation of microglial ROCK mediates major components of the microglial inflammatory response. Additional mechanisms such as interaction with autophagy may also contribute to the neuroprotective effects of ROCK inhibition. Interestingly, ROCK interacts with several brain factors that play a major role in dopaminergic neuron vulnerability such as NADPH-oxidase, angiotensin, and estrogen. ROCK inhibition may provide a new neuroprotective strategy for Parkinson’s disease. This is of particular interest because ROCK inhibitors are currently used against vascular diseases in clinical practice. However, it is necessary to develop more potent and selective ROCK inhibitors to reduce side effects and enhance the efficacy.
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Affiliation(s)
- Jose L. Labandeira-Garcia
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
| | - Ana I. Rodríguez-Perez
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
| | - Begoña Villar-Cheda
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
| | - Ana Borrajo
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
| | - Antonio Dominguez-Meijide
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
| | - Maria J. Guerra
- Laboratory of Neuroanatomy and Experimental Neurology, Department of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
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26
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González-Forero D, Moreno-López B. Retrograde response in axotomized motoneurons: nitric oxide as a key player in triggering reversion toward a dedifferentiated phenotype. Neuroscience 2014; 283:138-65. [PMID: 25168733 DOI: 10.1016/j.neuroscience.2014.08.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 08/03/2014] [Accepted: 08/14/2014] [Indexed: 12/11/2022]
Abstract
The adult brain retains a considerable capacity to functionally reorganize its circuits, which mainly relies on the prevalence of three basic processes that confer plastic potential: synaptic plasticity, plastic changes in intrinsic excitability and, in certain central nervous system (CNS) regions, also neurogenesis. Experimental models of peripheral nerve injury have provided a useful paradigm for studying injury-induced mechanisms of central plasticity. In particular, axotomy of somatic motoneurons triggers a robust retrograde reaction in the CNS, characterized by the expression of plastic changes affecting motoneurons, their synaptic inputs and surrounding glia. Axotomized motoneurons undergo a reprograming of their gene expression and biosynthetic machineries which produce cell components required for axonal regrowth and lead them to resume a functionally dedifferentiated phenotype characterized by the removal of afferent synaptic contacts, atrophy of dendritic arbors and an enhanced somato-dendritic excitability. Although experimental research has provided valuable clues to unravel many basic aspects of this central response, we are still lacking detailed information on the cellular/molecular mechanisms underlying its expression. It becomes clear, however, that the state-switch must be orchestrated by motoneuron-derived signals produced under the direction of the re-activated growth program. Our group has identified the highly reactive gas nitric oxide (NO) as one of these signals, by providing robust evidence for its key role to induce synapse elimination and increases in intrinsic excitability following motor axon damage. We have elucidated operational principles of the NO-triggered downstream transduction pathways mediating each of these changes. Our findings further demonstrate that de novo NO synthesis is not only "necessary" but also "sufficient" to promote the expression of at least some of the features that reflect reversion toward a dedifferentiated state in axotomized adult motoneurons.
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Affiliation(s)
- D González-Forero
- Grupo de Neurodegeneración y Neuroreparación (GRUNEDERE), Área de Fisiología, Instituto de Biomoléculas (INBIO), Facultad de Medicina, Universidad de Cádiz, Cádiz, Spain.
| | - B Moreno-López
- Grupo de Neurodegeneración y Neuroreparación (GRUNEDERE), Área de Fisiología, Instituto de Biomoléculas (INBIO), Facultad de Medicina, Universidad de Cádiz, Cádiz, Spain.
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27
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Roossien DH, Lamoureux P, Miller KE. Cytoplasmic dynein pushes the cytoskeletal meshwork forward during axonal elongation. J Cell Sci 2014; 127:3593-602. [PMID: 24951117 DOI: 10.1242/jcs.152611] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
During development, neurons send out axonal processes that can reach lengths hundreds of times longer than the diameter of their cell bodies. Recent studies indicate that en masse microtubule translocation is a significant mechanism underlying axonal elongation, but how cellular forces drive this process is unknown. Cytoplasmic dynein generates forces on microtubules in axons to power their movement through 'stop-and-go' transport, but whether these forces influence the bulk translocation of long microtubules embedded in the cytoskeletal meshwork has not been tested. Here, we use both function-blocking antibodies targeted to the dynein intermediate chain and the pharmacological dynein inhibitor ciliobrevin D to ask whether dynein forces contribute to en bloc cytoskeleton translocation. By tracking docked mitochondria as fiducial markers for bulk cytoskeleton movements, we find that translocation is reduced after dynein disruption. We then directly measure net force generation after dynein disruption and find a dramatic increase in axonal tension. Taken together, these data indicate that dynein generates forces that push the cytoskeletal meshwork forward en masse during axonal elongation.
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Affiliation(s)
- Douglas H Roossien
- Cell and Molecular Biology Program, Michigan State University, 288 Farm Ln Room 336, East Lansing, MI 48824, USA
| | - Phillip Lamoureux
- Department of Zoology, Michigan State University, 288 Farm Ln Room 336, East Lansing, MI 48824, USA
| | - Kyle E Miller
- Department of Zoology, Michigan State University, 288 Farm Ln Room 336, East Lansing, MI 48824, USA
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28
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Borrajo A, Rodriguez-Perez AI, Villar-Cheda B, Guerra MJ, Labandeira-Garcia JL. Inhibition of the microglial response is essential for the neuroprotective effects of Rho-kinase inhibitors on MPTP-induced dopaminergic cell death. Neuropharmacology 2014; 85:1-8. [PMID: 24878243 DOI: 10.1016/j.neuropharm.2014.05.021] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 03/18/2014] [Accepted: 05/14/2014] [Indexed: 01/20/2023]
Abstract
Several recent studies have shown that activation of the RhoA/Rho-associated kinase (ROCK) pathway is involved in the MPTP-induced dopaminergic cell degeneration and possibly in Parkinson's disease. ROCK inhibitors have been suggested as candidate neuroprotective drugs for Parkinson's disease. However, the mechanism responsible for the increased survival of dopaminergic neurons after treatment with ROCK inhibitors is not clear. We exposed primary (neuron-glia) mesencephalic cultures, cultures of the MES 23.5 dopaminergic neuron cell line and primary mesencephalic cultures lacking microglial cells to the dopaminergic neurotoxin MPP+ and the ROCK inhibitor Y-27632 in order to study the effects of ROCK inhibition on dopaminergic cell loss and the length of neurites of surviving dopaminergic neurons. In primary (neuron-glia) cultures, simultaneous treatment with MPP+ and the ROCK inhibitor significantly reduced the loss of dopaminergic neurons. In the absence of microglia, treatment with the ROCK inhibitor did not induce a significant reduction in the dopaminergic cell loss. Treatment with the ROCK inhibitor induced a significant decrease in axonal retraction in primary cultures with and without microglia and in cultures of the MES 23.5 neuron cell line. In conclusion, inhibition of microglial ROCK is essential for the neuroprotective effects of ROCK inhibitors against cell death induced by the dopaminergic neurotoxin MPP+. In addition, ROCK inhibition induced a direct effect against axonal retraction in surviving neurons. However, the latter effect was not sufficient to cause a significant increase in the survival of dopaminergic neurons after treatment with MPP+.
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Affiliation(s)
- Ana Borrajo
- Laboratory of Neuroanatomy and Experimental Neurology, Dept. of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain; Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
| | - Ana I Rodriguez-Perez
- Laboratory of Neuroanatomy and Experimental Neurology, Dept. of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain; Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
| | - Begoña Villar-Cheda
- Laboratory of Neuroanatomy and Experimental Neurology, Dept. of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain; Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
| | - Maria J Guerra
- Laboratory of Neuroanatomy and Experimental Neurology, Dept. of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain; Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain
| | - Jose L Labandeira-Garcia
- Laboratory of Neuroanatomy and Experimental Neurology, Dept. of Morphological Sciences, CIMUS, University of Santiago de Compostela, Santiago de Compostela, Spain; Networking Research Center on Neurodegenerative Diseases (CIBERNED), Spain.
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29
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Koch JC, Tönges L, Barski E, Michel U, Bähr M, Lingor P. ROCK2 is a major regulator of axonal degeneration, neuronal death and axonal regeneration in the CNS. Cell Death Dis 2014; 5:e1225. [PMID: 24832597 PMCID: PMC4047920 DOI: 10.1038/cddis.2014.191] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Revised: 03/26/2014] [Accepted: 03/28/2014] [Indexed: 12/19/2022]
Abstract
The Rho/ROCK/LIMK pathway is central for the mediation of repulsive environmental signals in the central nervous system. Several studies using pharmacological Rho-associated protein kinase (ROCK) inhibitors have shown positive effects on neurite regeneration and suggest additional pro-survival effects in neurons. However, as none of these drugs is completely target specific, it remains unclear how these effects are mediated and whether ROCK is really the most relevant target of the pathway. To answer these questions, we generated adeno-associated viral vectors to specifically downregulate ROCK2 and LIM domain kinase (LIMK)-1 in rat retinal ganglion cells (RGCs) in vitro and in vivo. We show here that specific knockdown of ROCK2 and LIMK1 equally enhanced neurite outgrowth of RGCs on inhibitory substrates and both induced substantial neuronal regeneration over distances of more than 5 mm after rat optic nerve crush (ONC) in vivo. However, only knockdown of ROCK2 but not LIMK1 increased survival of RGCs after optic nerve axotomy. Moreover, knockdown of ROCK2 attenuated axonal degeneration of the proximal axon after ONC assessed by in vivo live imaging. Mechanistically, we demonstrate here that knockdown of ROCK2 resulted in decreased intraneuronal activity of calpain and caspase 3, whereas levels of pAkt and collapsin response mediator protein 2 and autophagic flux were increased. Taken together, our data characterize ROCK2 as a specific therapeutic target in neurodegenerative diseases and demonstrate new downstream effects of ROCK2 including axonal degeneration, apoptosis and autophagy.
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Affiliation(s)
- J C Koch
- Department of Neurology, University Medicine Göttingen, Göttingen, Germany
| | - L Tönges
- Department of Neurology, University Medicine Göttingen, Göttingen, Germany
| | - E Barski
- Department of Neurology, University Medicine Göttingen, Göttingen, Germany
| | - U Michel
- Department of Neurology, University Medicine Göttingen, Göttingen, Germany
| | - M Bähr
- Department of Neurology, University Medicine Göttingen, Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - P Lingor
- Department of Neurology, University Medicine Göttingen, Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
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30
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The Beta-amyloid protein of Alzheimer's disease: communication breakdown by modifying the neuronal cytoskeleton. Int J Alzheimers Dis 2013; 2013:910502. [PMID: 24416616 PMCID: PMC3876695 DOI: 10.1155/2013/910502] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 11/07/2013] [Indexed: 01/28/2023] Open
Abstract
Alzheimer's disease (AD) is one of the most prevalent severe neurological disorders afflicting our aged population. Cognitive decline, a major symptom exhibited by AD patients, is associated with neuritic dystrophy, a degenerative growth state of neurites. The molecular mechanisms governing neuritic dystrophy remain unclear. Mounting evidence indicates that the AD-causative agent, β-amyloid protein (Aβ), induces neuritic dystrophy. Indeed, neuritic dystrophy is commonly found decorating Aβ-rich amyloid plaques (APs) in the AD brain. Furthermore, disruption and degeneration of the neuronal microtubule system in neurons forming dystrophic neurites may occur as a consequence of Aβ-mediated downstream signaling. This review defines potential molecular pathways, which may be modulated subsequent to Aβ-dependent interactions with the neuronal membrane as a consequence of increasing amyloid burden in the brain.
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31
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Roossien DH, Lamoureux P, Van Vactor D, Miller KE. Drosophila growth cones advance by forward translocation of the neuronal cytoskeletal meshwork in vivo. PLoS One 2013; 8:e80136. [PMID: 24244629 PMCID: PMC3823856 DOI: 10.1371/journal.pone.0080136] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 09/30/2013] [Indexed: 12/29/2022] Open
Abstract
In vitro studies conducted in Aplysia and chick sensory neurons indicate that in addition to microtubule assembly, long microtubules in the C-domain of the growth cone move forward as a coherent bundle during axonal elongation. Nonetheless, whether this mode of microtubule translocation contributes to growth cone motility in vivo is unknown. To address this question, we turned to the model system Drosophila. Using docked mitochondria as fiduciary markers for the translocation of long microtubules, we first examined motion along the axon to test if the pattern of axonal elongation is conserved between Drosophila and other species in vitro. When Drosophila neurons were cultured on Drosophila extracellular matrix proteins collected from the Drosophila Kc167 cell line, docked mitochondria moved in a pattern indicative of bulk microtubule translocation, similar to that observed in chick sensory neurons grown on laminin. To investigate whether the C-domain is stationary or advances in vivo, we tracked the movement of mitochondria during elongation of the aCC motor neuron in stage 16 Drosophila embryos. We found docked mitochondria moved forward along the axon shaft and in the growth cone C-domain. This work confirms that the physical mechanism of growth cone advance is similar between Drosophila and vertebrate neurons and suggests forward translocation of the microtubule meshwork in the axon underlies the advance of the growth cone C-domain in vivo. These results highlight the need for incorporating en masse microtubule translocation, in addition to assembly, into models of axonal elongation.
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Affiliation(s)
- Douglas H. Roossien
- Cell and Molecular Biology Program, Michigan State University, East Lansing, Michigan, United States of America
| | - Phillip Lamoureux
- Department of Zoology, Michigan State University, East Lansing, Michigan, United States of America
| | - David Van Vactor
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Kyle E. Miller
- Department of Zoology, Michigan State University, East Lansing, Michigan, United States of America
- * E-mail:
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32
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Vasyagina NU, Sotnikov OS, Kokurina TN, Krasnova TV. Contractile activity of living isolated neurons and its inhibition by cytochalasin B. Bull Exp Biol Med 2013; 155:280-3. [PMID: 24131009 DOI: 10.1007/s10517-013-2132-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Contractile activity of damaged neuronal axons of Lymnaea stagnalis and Planorbis corneus vulgaris mollusks and the possibility of inhibiting their retraction by cytochalasin B were studied. In experimental series I (control), the neuronal axons contracted in Ringer's fluid in 90% cases. In series II and III (cytochalasin B in concentrations of 0.02 and 0.2 mM), the percentage of non-contracting neurons was 50 and 70%, respectively. Presumably, the fiber retraction mechanism was involved in the formation of diastasis after nerve cutting and damage to conduction tracts. The nerve diastasis formed at the expense of not only elastic characteristics of the nerve sheath and glia, but also due to nerve fiber retraction. Experiments with cytochalasin B demonstrated that F-actin filaments were involved in the retraction of myelin-free nerve fibers.
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Affiliation(s)
- N U Vasyagina
- Laboratory of Functional Morphology and Physiology of the Neuron, I. P. Pavlov Institute of Physiology of the Russian Academy of Sciences, St. Petersburg, Russia.
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33
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Rodriguez-Perez AI, Dominguez-Meijide A, Lanciego JL, Guerra MJ, Labandeira-Garcia JL. Inhibition of Rho kinase mediates the neuroprotective effects of estrogen in the MPTP model of Parkinson's disease. Neurobiol Dis 2013; 58:209-19. [DOI: 10.1016/j.nbd.2013.06.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 05/27/2013] [Accepted: 06/04/2013] [Indexed: 11/26/2022] Open
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34
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Öztürk G, Cengiz N, Erdoğan E, Him A, Oğuz EK, Yenidünya E, Ayşit N. Two distinct types of dying back axonal degenerationin vitro. Neuropathol Appl Neurobiol 2013; 39:362-76. [DOI: 10.1111/j.1365-2990.2012.01295.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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35
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Rallis A, Lu B, Ng J. Molecular chaperones protect against JNK- and Nmnat-regulated axon degeneration in Drosophila. J Cell Sci 2012; 126:838-49. [PMID: 23264732 DOI: 10.1242/jcs.117259] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Axon degeneration is observed at the early stages of many neurodegenerative conditions and this often leads to subsequent neuronal loss. We previously showed that inactivating the c-Jun N-terminal kinase (JNK) pathway leads to axon degeneration in Drosophila mushroom body (MB) neurons. To understand this process, we screened candidate suppressor genes and found that the Wallerian degeneration slow (Wld(S)) protein blocked JNK axonal degeneration. Although the nicotinamide mononucleotide adenylyltransferase (Nmnat1) portion of Wld(S) is required, we found that its nicotinamide adenine dinucleotide (NAD(+)) enzyme activity and the Wld(S) N-terminus (N70) are dispensable, unlike axotomy models of neurodegeneration. We suggest that Wld(S)-Nmnat protects against axonal degeneration through chaperone activity. Furthermore, ectopically expressed heat shock proteins (Hsp26 and Hsp70) also protected against JNK and Nmnat degeneration phenotypes. These results suggest that molecular chaperones are key in JNK- and Nmnat-regulated axonal protective functions.
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Affiliation(s)
- Andrew Rallis
- MRC Centre for Developmental Neurobiology, King's College London, Guy's Campus, London SE1 1UL, UK.
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36
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Tönges L, Frank T, Tatenhorst L, Saal KA, Koch JC, Szegő ÉM, Bähr M, Weishaupt JH, Lingor P. Inhibition of rho kinase enhances survival of dopaminergic neurons and attenuates axonal loss in a mouse model of Parkinson's disease. Brain 2012; 135:3355-70. [PMID: 23087045 PMCID: PMC3501973 DOI: 10.1093/brain/aws254] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 07/18/2012] [Accepted: 07/21/2012] [Indexed: 01/08/2023] Open
Abstract
Axonal degeneration is one of the earliest features of Parkinson's disease pathology, which is followed by neuronal death in the substantia nigra and other parts of the brain. Inhibition of axonal degeneration combined with cellular neuroprotection therefore seem key to targeting an early stage in Parkinson's disease progression. Based on our previous studies in traumatic and neurodegenerative disease models, we have identified rho kinase as a molecular target that can be manipulated to disinhibit axonal regeneration and improve survival of lesioned central nervous system neurons. In this study, we examined the neuroprotective potential of pharmacological rho kinase inhibition mediated by fasudil in the in vitro 1-methyl-4-phenylpyridinium cell culture model and in the subchronic in vivo 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson's disease. Application of fasudil resulted in a significant attenuation of dopaminergic cell loss in both paradigms. Furthermore, dopaminergic terminals were preserved as demonstrated by analysis of neurite network in vitro, striatal fibre density and by neurochemical analysis of the levels of dopamine and its metabolites in the striatum. Behavioural tests demonstrated a clear improvement in motor performance after fasudil treatment. The Akt survival pathway was identified as an important molecular mediator for neuroprotective effects of rho kinase inhibition in our paradigm. We conclude that inhibition of rho kinase using the clinically approved small molecule inhibitor fasudil may be a promising new therapeutic strategy for Parkinson's disease.
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MESH Headings
- 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine/analogs & derivatives
- 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine/pharmacology
- 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine/therapeutic use
- 1-Methyl-4-phenylpyridinium/toxicity
- Animals
- Axons/drug effects
- Axons/pathology
- Behavior, Animal/drug effects
- Behavior, Animal/physiology
- Cell Survival/drug effects
- Cell Survival/physiology
- Cells, Cultured
- Corpus Striatum/metabolism
- Disease Models, Animal
- Dopamine/metabolism
- Dopaminergic Neurons/enzymology
- Dopaminergic Neurons/pathology
- Dopaminergic Neurons/physiology
- MPTP Poisoning/drug therapy
- MPTP Poisoning/enzymology
- Male
- Mice
- Mice, Inbred C57BL
- Nerve Degeneration/chemically induced
- Nerve Degeneration/drug therapy
- Nerve Degeneration/enzymology
- Neurites/pathology
- Neuroprotective Agents/metabolism
- Neuroprotective Agents/pharmacology
- Neuroprotective Agents/therapeutic use
- Parkinson Disease, Secondary/chemically induced
- Parkinson Disease, Secondary/drug therapy
- Parkinson Disease, Secondary/enzymology
- Parkinson Disease, Secondary/pathology
- Proto-Oncogene Proteins c-akt/drug effects
- Proto-Oncogene Proteins c-akt/metabolism
- Rats
- Rats, Wistar
- Substantia Nigra/drug effects
- Substantia Nigra/enzymology
- rho-Associated Kinases/antagonists & inhibitors
- rho-Associated Kinases/physiology
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Affiliation(s)
- Lars Tönges
- 1 Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
| | - Tobias Frank
- 1 Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
| | - Lars Tatenhorst
- 1 Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
| | - Kim A. Saal
- 1 Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
| | - Jan C. Koch
- 1 Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
| | - Éva M. Szegő
- 2 Cluster of Excellence “Nanoscale Microscopy and Molecular Physiology of the Brain” (CNMPB), 37075 Göttingen, Germany
- 3 Department of Neurodegeneration and Restorative Research, University of Göttingen, 37075 Göttingen, Germany
| | - Mathias Bähr
- 1 Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
- 2 Cluster of Excellence “Nanoscale Microscopy and Molecular Physiology of the Brain” (CNMPB), 37075 Göttingen, Germany
| | | | - Paul Lingor
- 1 Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
- 2 Cluster of Excellence “Nanoscale Microscopy and Molecular Physiology of the Brain” (CNMPB), 37075 Göttingen, Germany
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37
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Cengiz N, Oztürk G, Erdoğan E, Him A, Oğuz EK. Consequences of neurite transection in vitro. J Neurotrauma 2012; 29:2465-74. [PMID: 20121423 DOI: 10.1089/neu.2009.0947] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In order to quantify degenerative and regenerative changes and analyze the contribution of multiple factors to the outcome after neurite transection, we cultured adult mouse dorsal root ganglion neurons, and with a precise laser beam, we transected the nerve fibers they extended. Cell preparations were continuously visualized for 24 h with time-lapse microscopy. More distal cuts caused a more elongated field of degeneration, while thicker neurites degenerated faster than thinner ones. Transected neurites degenerated more if the uncut neurites of the same neuron simultaneously degenerated. If any of these uncut processes regenerated, the transected neurites underwent less degeneration. Regeneration of neurites was limited to distal cuts. Unipolar neurons had shorter regeneration than multipolar ones. Branching slowed the regenerative process, while simultaneous degeneration of uncut neurites increased it. Proximal lesions, small neuronal size, and extensive and rapid neurite degeneration were predictive of death of an injured neuron, which typically displayed necrotic rather than apoptotic form. In conclusion, this in vitro model proved useful in unmasking many new aspects and correlates of mechanically-induced neurite injury.
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Affiliation(s)
- Nurettin Cengiz
- Department of Histology and Embryology, Yüzüncü Yil University Medical School, Van, Turkey
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38
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Kudryashova IV, Onufriev MV, Gulyaeva NV. Structural and functional features of presynaptic afferents and their dependence on caspase-3 activity in rat hippocampal slices. NEUROCHEM J+ 2012. [DOI: 10.1134/s1819712411040106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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39
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Lingor P, Koch JC, Tönges L, Bähr M. Axonal degeneration as a therapeutic target in the CNS. Cell Tissue Res 2012; 349:289-311. [PMID: 22392734 PMCID: PMC3375418 DOI: 10.1007/s00441-012-1362-3] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 02/02/2012] [Indexed: 12/15/2022]
Abstract
Degeneration of the axon is an important step in the pathomechanism of traumatic, inflammatory and degenerative neurological diseases. Increasing evidence suggests that axonal degeneration occurs early in the course of these diseases and therefore represents a promising target for future therapeutic strategies. We review the evidence for axonal destruction from pathological findings and animal models with particular emphasis on neurodegenerative and neurotraumatic disorders. We discuss the basic morphological and temporal modalities of axonal degeneration (acute, chronic and focal axonal degeneration and Wallerian degeneration). Based on the mechanistic concepts, we then delineate in detail the major molecular mechanisms that underlie the degenerative cascade, such as calcium influx, axonal transport, protein aggregation and autophagy. We finally concentrate on putative therapeutic targets based on the mechanistic prerequisites.
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Affiliation(s)
- Paul Lingor
- Department of Neurology, University Medicine Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany.
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Ruiz-Loredo AY, López-Colomé AM. New insights into the regulation of myosin light chain phosphorylation in retinal pigment epithelial cells. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 293:85-121. [PMID: 22251559 DOI: 10.1016/b978-0-12-394304-0.00008-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The retinal pigment epithelium (RPE) plays an essential role in the function of the neural retina and the maintenance of vision. Most of the functions displayed by RPE require a dynamic organization of the acto-myosin cytoskeleton. Myosin II, a main cytoskeletal component in muscle and non-muscle cells, is directly involved in force generation required for organelle movement, selective molecule transport within cell compartments, exocytosis, endocytosis, phagocytosis, and cell division, among others. Contractile processes are triggered by the phosphorylation of myosin II light chains (MLCs), which promotes actin-myosin interaction and the assembly of contractile fibers. Considerable evidence indicates that non-muscle myosin II activation is critically involved in various pathological states, increasing the interest in studying the signaling pathways controlling MLC phosphorylation. Particularly, recent findings suggest a role for non-muscle myosin II-induced contraction in RPE cell transformation involved in the establishment of numerous retinal diseases. This review summarizes the current knowledge regarding myosin function in RPE cells, as well as the signaling networks leading to MLC phosphorylation under pathological conditions. Understanding the molecular mechanisms underlying RPE dysfunction would improve the development of new therapies for the treatment or prevention of different ocular disorders leading to blindness.
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Affiliation(s)
- Ariadna Yolanda Ruiz-Loredo
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico DF, Mexico
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Ma CHE, Omura T, Cobos EJ, Latrémolière A, Ghasemlou N, Brenner GJ, van Veen E, Barrett L, Sawada T, Gao F, Coppola G, Gertler F, Costigan M, Geschwind D, Woolf CJ. Accelerating axonal growth promotes motor recovery after peripheral nerve injury in mice. J Clin Invest 2011; 121:4332-47. [PMID: 21965333 DOI: 10.1172/jci58675] [Citation(s) in RCA: 179] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 08/16/2011] [Indexed: 11/17/2022] Open
Abstract
Although peripheral nerves can regenerate after injury, proximal nerve injury in humans results in minimal restoration of motor function. One possible explanation for this is that injury-induced axonal growth is too slow. Heat shock protein 27 (Hsp27) is a regeneration-associated protein that accelerates axonal growth in vitro. Here, we have shown that it can also do this in mice after peripheral nerve injury. While rapid motor and sensory recovery occurred in mice after a sciatic nerve crush injury, there was little return of motor function after sciatic nerve transection, because of the delay in motor axons reaching their target. This was not due to a failure of axonal growth, because injured motor axons eventually fully re-extended into muscles and sensory function returned; rather, it resulted from a lack of motor end plate reinnervation. Tg mice expressing high levels of Hsp27 demonstrated enhanced restoration of motor function after nerve transection/resuture by enabling motor synapse reinnervation, but only within 5 weeks of injury. In humans with peripheral nerve injuries, shorter wait times to decompression surgery led to improved functional recovery, and, while a return of sensation occurred in all patients, motor recovery was limited. Thus, absence of motor recovery after nerve damage may result from a failure of synapse reformation after prolonged denervation rather than a failure of axonal growth.
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Affiliation(s)
- Chi Him Eddie Ma
- Program in Neurobiology and F.M. Kirby Neurobiology Center, Children’s Hospital Boston, and Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, USA.
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Bush WS, McCauley JL, DeJager PL, Dudek SM, Hafler DA, Gibson RA, Matthews PM, Kappos L, Naegelin Y, Polman CH, Hauser SL, Oksenberg J, Haines JL, Ritchie MD. A knowledge-driven interaction analysis reveals potential neurodegenerative mechanism of multiple sclerosis susceptibility. Genes Immun 2011; 12:335-40. [PMID: 21346779 PMCID: PMC3136581 DOI: 10.1038/gene.2011.3] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 11/03/2010] [Accepted: 11/11/2010] [Indexed: 02/05/2023]
Abstract
Gene-gene interactions are proposed as an important component of the genetic architecture of complex diseases, and are just beginning to be evaluated in the context of genome-wide association studies (GWAS). In addition to detecting epistasis, a benefit to interaction analysis is that it also increases power to detect weak main effects. We conducted a knowledge-driven interaction analysis of a GWAS of 931 multiple sclerosis (MS) trios to discover gene-gene interactions within established biological contexts. We identify heterogeneous signals, including a gene-gene interaction between CHRM3 (muscarinic cholinergic receptor 3) and MYLK (myosin light-chain kinase) (joint P=0.0002), an interaction between two phospholipase C-β isoforms, PLCβ1 and PLCβ4 (joint P=0.0098), and a modest interaction between ACTN1 (actinin alpha 1) and MYH9 (myosin heavy chain 9) (joint P=0.0326), all localized to calcium-signaled cytoskeletal regulation. Furthermore, we discover a main effect (joint P=5.2E-5) previously unidentified by single-locus analysis within another related gene, SCIN (scinderin), a calcium-binding cytoskeleton regulatory protein. This work illustrates that knowledge-driven interaction analysis of GWAS data is a feasible approach to identify new genetic effects. The results of this study are among the first gene-gene interactions and non-immune susceptibility loci for MS. Further, the implicated genes cluster within inter-related biological mechanisms that suggest a neurodegenerative component to MS.
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Affiliation(s)
- William S. Bush
- Center for Human Genetics Research, Dept of Molecular Physiology and Biophysics, Vanderbilt University, 519 Light Hall, Nashville, TN 37232
| | - Jacob L. McCauley
- Miami Institute for Human Genomics, University of Miami, Miller School of Medicine, 1501 NW 10 Ave, Miami, FL 33136
| | - Philip L. DeJager
- Division of Molecular Immunology, Center for Neurologic Diseases, Dept of Neurology, Brigham & Women’s Hospital and Harvard Medical School, 77 Ave Louis Pasteur, Boston, MA 02115
| | - Scott M. Dudek
- Center for Human Genetics Research, Dept of Molecular Physiology and Biophysics, Vanderbilt University, 519 Light Hall, Nashville, TN 37232
| | - David A. Hafler
- Division of Molecular Immunology, Center for Neurologic Diseases, Dept of Neurology, Brigham & Women’s Hospital and Harvard Medical School, 77 Ave Louis Pasteur, Boston, MA 02115
| | - Rachel A. Gibson
- GlaxoSmithKline, Research & Development, 980 Great West Rd., Brentford, Middlesex, UK TW8 9GS
| | - Paul M. Matthews
- GlaxoSmithKline, Research & Development, 980 Great West Rd., Brentford, Middlesex, UK TW8 9GS
| | - Ludwig Kappos
- Dept of Neurology, University Hospital Basel, Spitalstrasse21/Petersgraben 4, 4031 Basel, Switzerland
| | - Yvonne Naegelin
- Dept of Neurology, University Hospital Basel, Spitalstrasse21/Petersgraben 4, 4031 Basel, Switzerland
| | - Chris H. Polman
- Dept of Neurology, Vrije Universiteit Medical Centre, De Boelelaan 1105, 1081 HV Amsterdam, The Netherlands
| | | | - Stephen L. Hauser
- Dept of Neurology, School of Medicine, University of California, San Francisco, M798, Box 0114, San Francisco, CA 34143
| | - Jorge Oksenberg
- Dept of Neurology, School of Medicine, University of California, San Francisco, M798, Box 0114, San Francisco, CA 34143
| | - Jonathan L. Haines
- Center for Human Genetics Research, Dept of Molecular Physiology and Biophysics, Vanderbilt University, 519 Light Hall, Nashville, TN 37232
| | - Marylyn D. Ritchie
- Center for Human Genetics Research, Dept of Molecular Physiology and Biophysics, Vanderbilt University, 519 Light Hall, Nashville, TN 37232
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Suter DM, Miller KE. The emerging role of forces in axonal elongation. Prog Neurobiol 2011; 94:91-101. [PMID: 21527310 DOI: 10.1016/j.pneurobio.2011.04.002] [Citation(s) in RCA: 171] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 03/18/2011] [Accepted: 04/06/2011] [Indexed: 11/26/2022]
Abstract
An understanding of how axons elongate is needed to develop rational strategies to treat neurological diseases and nerve injury. Growth cone-mediated neuronal elongation is currently viewed as occurring through cytoskeletal dynamics involving the polymerization of actin and tubulin subunits at the tip of the axon. However, recent work suggests that axons and growth cones also generate forces (through cytoskeletal dynamics, kinesin, dynein, and myosin), forces induce axonal elongation, and axons lengthen by stretching. This review highlights results from various model systems (Drosophila, Aplysia, Xenopus, chicken, mouse, rat, and PC12 cells), supporting a role for forces, bulk microtubule movements, and intercalated mass addition in the process of axonal elongation. We think that a satisfying answer to the question, "How do axons grow?" will come by integrating the best aspects of biophysics, genetics, and cell biology.
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Affiliation(s)
- Daniel M Suter
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907-2054, United States.
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Kilinc D, Peyrin JM, Soubeyre V, Magnifico S, Saias L, Viovy JL, Brugg B. Wallerian-like degeneration of central neurons after synchronized and geometrically registered mass axotomy in a three-compartmental microfluidic chip. Neurotox Res 2011; 19:149-61. [PMID: 20162389 PMCID: PMC3006648 DOI: 10.1007/s12640-010-9152-8] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Revised: 10/15/2009] [Accepted: 01/12/2010] [Indexed: 01/09/2023]
Abstract
Degeneration of central axons may occur following injury or due to various diseases and it involves complex molecular mechanisms that need to be elucidated. Existing in vitro axotomy models are difficult to perform, and they provide limited information on the localization of events along the axon. We present here a novel experimental model system, based on microfluidic isolation, which consists of three distinct compartments, interconnected by parallel microchannels allowing axon outgrowth. Neurons cultured in one compartment successfully elongated their axons to cross a short central compartment and invade the outermost compartment. This design provides an interesting model system for studying axonal degeneration and death mechanisms, with a previously impossible spatial and temporal control on specific molecular pathways. We provide a proof-of-concept of the system by reporting its application to a well-characterized experimental paradigm, axotomy-induced Wallerian degeneration in primary central neurons. Using this model, we applied localized central axotomy by a brief, isolated flux of detergent. We report that mouse embryonic cortical neurons exhibit rapid Wallerian-like distal degeneration but no somatic death following central axotomy. Distal axons show progressive degeneration leading to axonal beading and cytoskeletal fragmentation within a few hours after axotomy. Degeneration is asynchronous, reminiscent of in vivo Wallerian degeneration. Axonal cytoskeletal fragmentation is significantly delayed with nicotinamide adenine dinucleotide pretreatment, but it does not change when distal calpain or caspase activity is inhibited. These findings, consistent with previous experiments in vivo, confirm the power and biological relevance of this microfluidic architecture.
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Affiliation(s)
- Devrim Kilinc
- Laboratoire de Neurobiologie des Processus Adaptatifs, UMR 7102 CNRS/UPMC, Univ. P. et M. Curie, Bat B, 6eme Etage, Case courrier 12, 9 Quai St. Bernard, 75252 Paris, France
| | - Jean-Michel Peyrin
- Laboratoire de Neurobiologie des Processus Adaptatifs, UMR 7102 CNRS/UPMC, Univ. P. et M. Curie, Bat B, 6eme Etage, Case courrier 12, 9 Quai St. Bernard, 75252 Paris, France
| | - Vanessa Soubeyre
- Laboratoire de Neurobiologie des Processus Adaptatifs, UMR 7102 CNRS/UPMC, Univ. P. et M. Curie, Bat B, 6eme Etage, Case courrier 12, 9 Quai St. Bernard, 75252 Paris, France
| | - Sébastien Magnifico
- Laboratoire de Neurobiologie des Processus Adaptatifs, UMR 7102 CNRS/UPMC, Univ. P. et M. Curie, Bat B, 6eme Etage, Case courrier 12, 9 Quai St. Bernard, 75252 Paris, France
| | - Laure Saias
- Laboratoire Physicochimie-Curie, UMR 168 Institut Curie/CNRS/UPMC, Paris, France
| | - Jean-Louis Viovy
- Laboratoire Physicochimie-Curie, UMR 168 Institut Curie/CNRS/UPMC, Paris, France
| | - Bernard Brugg
- Laboratoire de Neurobiologie des Processus Adaptatifs, UMR 7102 CNRS/UPMC, Univ. P. et M. Curie, Bat B, 6eme Etage, Case courrier 12, 9 Quai St. Bernard, 75252 Paris, France
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Moreno-López B, Sunico CR, González-Forero D. NO orchestrates the loss of synaptic boutons from adult "sick" motoneurons: modeling a molecular mechanism. Mol Neurobiol 2010; 43:41-66. [PMID: 21190141 DOI: 10.1007/s12035-010-8159-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 12/02/2010] [Indexed: 12/14/2022]
Abstract
Synapse elimination is the main factor responsible for the cognitive decline accompanying many of the neuropathological conditions affecting humans. Synaptic stripping of motoneurons is also a common hallmark of several motor pathologies. Therefore, knowledge of the molecular basis underlying this plastic process is of central interest for the development of new therapeutic tools. Recent advances from our group highlight the role of nitric oxide (NO) as a key molecule triggering synapse loss in two models of motor pathologies. De novo expression of the neuronal isoform of NO synthase (nNOS) in motoneurons commonly occurs in response to the physical injury of a motor nerve and in the course of amyotrophic lateral sclerosis. In both conditions, this event precedes synaptic withdrawal from motoneurons. Strikingly, nNOS-synthesized NO is "necessary" and "sufficient" to induce synaptic detachment from motoneurons. The mechanism involves a paracrine/retrograde action of NO on pre-synaptic structures, initiating a downstream signaling cascade that includes sequential activation of (1) soluble guanylyl cyclase, (2) cyclic guanosine monophosphate-dependent protein kinase, and (3) RhoA/Rho kinase (ROCK) signaling. Finally, ROCK activation promotes phosphorylation of regulatory myosin light chain, which leads to myosin activation and actomyosin contraction. This latter event presumably contributes to the contractile force to produce ending axon retraction. Several findings support that this mechanism may operate in the most prevalent neurodegenerative diseases.
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Affiliation(s)
- Bernardo Moreno-López
- Grupo de NeuroDegeneración y NeuroReparación (GRUNEDERE), Área de Fisiología, Facultad de Medicina, Universidad de Cádiz, Plaza Falla, 9, 11003 Cádiz, Spain.
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Norman LL, Aranda-Espinoza H. Cortical Neuron Outgrowth is Insensitive to Substrate Stiffness. Cell Mol Bioeng 2010. [DOI: 10.1007/s12195-010-0137-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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Abstract
Interactions between dynamic microtubules and actin filaments are essential to a wide range of cell biological processes including cell division, motility and morphogenesis. In neuronal growth cones, interactions between microtubules and actin filaments in filopodia are necessary for growth cones to make a turn. Growth-cone turning is a fundamental behaviour during axon guidance, as correct navigation of the growth cone through the embryo is required for it to locate an appropriate synaptic partner. Microtubule-actin filament interactions also occur in the transition zone and central domain of the growth cone, where actin arcs exert compressive forces to corral microtubules into the core of the growth cone and thereby facilitate microtubule bundling, a requirement for axon formation. We now have a fairly comprehensive understanding of the dynamic behaviour of the cytoskeleton in growth cones, and the stage is set for discovering the molecular machinery that enables microtubule-actin filament coupling in growth cones, as well as the intracellular signalling pathways that regulate these interactions. Furthermore, recent experiments suggest that microtubule-actin filament interactions might also be important for the formation of dendritic spines from filopodia in mature neurons. Therefore, the mechanisms coupling microtubules to actin filaments in growth-cone turning and dendritic-spine maturation might be conserved.
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Affiliation(s)
- Sara Geraldo
- The MRC Centre for Developmental Neurobiology, New Hunts House, Guy's Campus, King's College London, London SE1 1UL, UK
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Kollins KM, Hu J, Bridgman PC, Huang YQ, Gallo G. Myosin-II negatively regulates minor process extension and the temporal development of neuronal polarity. Dev Neurobiol 2009; 69:279-98. [PMID: 19224562 DOI: 10.1002/dneu.20704] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The earliest stage in the development of neuronal polarity is characterized by extension of undifferentiated "minor processes" (MPs), which subsequently differentiate into the axon and dendrites. We investigated the role of the myosin II motor protein in MP extension using forebrain and hippocampal neuron cultures. Chronic treatment of neurons with the myosin II ATPase inhibitor blebbistatin increased MP length, which was also seen in myosin IIB knockouts. Through live-cell imaging, we demonstrate that myosin II inhibition triggers rapid minor process extension to a maximum length range. Myosin II activity is determined by phosphorylation of its regulatory light chains (rMLC) and mediated by myosin light chain kinase (MLCK) or RhoA-kinase (ROCK). Pharmacological inhibition of MLCK or ROCK increased MP length moderately, with combined inhibition of these kinases resulting in an additive increase in MP length similar to the effect of direct inhibition of myosin II. Selective inhibition of RhoA signaling upstream of ROCK, with cell-permeable C3 transferase, increased both the length and number of MPs. To determine whether myosin II affected development of neuronal polarity, MP differentiation was examined in cultures treated with direct or indirect myosin II inhibitors. Significantly, inhibition of myosin II, MLCK, or ROCK accelerated the development of neuronal polarity. Increased myosin II activity, through constitutively active MLCK or RhoA, decreased both the length and number of MPs and, consequently, delayed or abolished the development of neuronal polarity. Together, these data indicate that myosin II negatively regulates MP extension, and the developmental time course for axonogenesis.
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Affiliation(s)
- K M Kollins
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129, USA.
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Shah SB, Nolan R, Davis E, Stokin GB, Niesman I, Canto I, Glabe C, Goldstein LSB. Examination of potential mechanisms of amyloid-induced defects in neuronal transport. Neurobiol Dis 2009; 36:11-25. [PMID: 19497367 DOI: 10.1016/j.nbd.2009.05.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Revised: 05/03/2009] [Accepted: 05/25/2009] [Indexed: 01/31/2023] Open
Abstract
Microtubule-based neuronal transport pathways are impaired during the progression of Alzheimer's disease and other neurodegenerative conditions. However, mechanisms leading to defects in transport remain to be determined. We quantified morphological changes in neuronal cells following treatment with fibrils and unaggregated peptides of beta-amyloid (Abeta). Abeta fibrils induce axonal and dendritic swellings indicative of impaired transport. In contrast, Abeta peptides induce a necrotic phenotype in both neurons and non-neuronal cells. We tested several popular hypotheses by which aggregated Abeta could disrupt transport. Using fluorescent polystyrene beads, we developed experimental models of physical blockage and localized release of reactive oxygen species (ROS) that reliably induce swellings. Like the beads, Abeta fibrils localize in close proximity to swellings; however, fibril internalization is not required for disrupting transport. ROS and membrane permeability are also unlikely to be responsible for fibril-mediated toxicity. Collectively, our results indicate that multiple initiating factors converge upon pathways of defective transport.
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Affiliation(s)
- Sameer B Shah
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA
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Orlova I, Silver L, Gallo G. Regulation of actomyosin contractility by PI3K in sensory axons. Dev Neurobiol 2008; 67:1843-51. [PMID: 17701990 DOI: 10.1002/dneu.20558] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Phosphatidylinositol 3-kinase (PI3K) activity is known to be required for the extension of embryonic sensory axons. Inhibition of PI3K has also been shown to mediate axon retraction and growth cone collapse in response to semaphorin 3A. However, the effects of inhibiting PI3K on the neuronal cytoskeleton are not well characterized. We have previously reported that semaphorin 3A-induced axon retraction involves activation of myosin II, the formation of an intra-axonal F-actin bundle cytoskeleton, and blocks the formation of F-actin patches that serve as precursors to filopodial formation in axons. We now report that inhibition of PI3K results in activation of myosin II in axons. Inhibition of myosin II activity, or its upstream regulatory kinase RhoA-kinase, blocked axon retraction induced by inhibition of PI3K. In addition, inhibition of PI3K also induced intra-axonal F-actin bundles, which likely serve as a substratum for myosin II-based force generation during axon retraction. In axons, filopodia are formed from axonal F-actin patch precursors. Analysis of axonal F-actin patch formation in eYFP-actin expressing neurons revealed that inhibition of PI3K blocked formation of axonal F-actin patches, and thus filopodial formation. These data provide insights into the regulation of the neuronal cytoskeleton by PI3K and are consistent with the notion that decreased levels of PI3K activity mediate axon retraction and growth cone collapse in response to semaphorin 3A.
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Affiliation(s)
- Irina Orlova
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
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