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Gordon T. Brief Electrical Stimulation Promotes Recovery after Surgical Repair of Injured Peripheral Nerves. Int J Mol Sci 2024; 25:665. [PMID: 38203836 PMCID: PMC10779324 DOI: 10.3390/ijms25010665] [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: 10/13/2023] [Revised: 12/07/2023] [Accepted: 12/08/2023] [Indexed: 01/12/2024] Open
Abstract
Injured peripheral nerves regenerate their axons in contrast to those in the central nervous system. Yet, functional recovery after surgical repair is often disappointing. The basis for poor recovery is progressive deterioration with time and distance of the growth capacity of the neurons that lose their contact with targets (chronic axotomy) and the growth support of the chronically denervated Schwann cells (SC) in the distal nerve stumps. Nonetheless, chronically denervated atrophic muscle retains the capacity for reinnervation. Declining electrical activity of motoneurons accompanies the progressive fall in axotomized neuronal and denervated SC expression of regeneration-associated-genes and declining regenerative success. Reduced motoneuronal activity is due to the withdrawal of synaptic contacts from the soma. Exogenous neurotrophic factors that promote nerve regeneration can replace the endogenous factors whose expression declines with time. But the profuse axonal outgrowth they provoke and the difficulties in their delivery hinder their efficacy. Brief (1 h) low-frequency (20 Hz) electrical stimulation (ES) proximal to the injury site promotes the expression of endogenous growth factors and, in turn, dramatically accelerates axon outgrowth and target reinnervation. The latter ES effect has been demonstrated in both rats and humans. A conditioning ES of intact nerve days prior to nerve injury increases axonal outgrowth and regeneration rate. Thereby, this form of ES is amenable for nerve transfer surgeries and end-to-side neurorrhaphies. However, additional surgery for applying the required electrodes may be a hurdle. ES is applicable in all surgeries with excellent outcomes.
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Affiliation(s)
- Tessa Gordon
- Division of Reconstructive Surgery, Department of Surgery, University of Toronto, Toronto, ON M4G 1X8, Canada
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2
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Kakuta W, Matsunaga S, Otsu Y, Kitamura K, Abe S, Yajima Y, Sekine H. Regeneration of sensory nerve branches in extraction socket and surrounding alveolar bone in rat: immunohistochemical observation of the axon and myelin sheath changes. Odontology 2022:10.1007/s10266-022-00772-y. [DOI: 10.1007/s10266-022-00772-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Accepted: 11/15/2022] [Indexed: 12/04/2022]
Abstract
AbstractThe purpose of this study was to investigate the process and derivation of the distribution of the sensory nerves that appear in the extraction socket and surrounding alveolar bone following tooth extraction. The right mandibular first molar of rats and periodontal ligament were extracted as a single mass, and the mandible was harvested after days 1, 3, 5, and 7 after extraction. Serial sections of 7 µm thickness were prepared for the proximal root (Section A), buccolingual root (Section B), and centrifugal root (Section C) of the first molar. H–E staining and immunohistochemical staining with anti-S100 antibody and anti-NF-L antibody were carried out. The presence of nerve fiber bundles in the blood clot was already evident on post-extraction day 3, and on post-extraction day 7. On day 3, the number of axons in Sections B and C had greatly decreased, indicating that, after extraction, the connection between peripheral nerve tissue and the trigeminal ganglion was temporarily markedly reduced in the region of the alveolar branch. Although the myelin sheaths were regenerating on day 5, the majority of the axons of the alveolar branches extending from the inferior alveolar nerve were seen to be extremely thin and scattered, despite their further regeneration. The above results suggest that the newly myelinated nerves are actually derived from the bone marrow to the extraction socket, so few nerves, rather than being derived from the alveolar branches that had innervated the extracted tooth.
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3
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Khaitin A. Calcium in Neuronal and Glial Response to Axotomy. Int J Mol Sci 2021; 22:ijms222413344. [PMID: 34948141 PMCID: PMC8706492 DOI: 10.3390/ijms222413344] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 12/09/2021] [Accepted: 12/10/2021] [Indexed: 11/16/2022] Open
Abstract
Neurotrauma assumes an instant or delayed disconnection of axons (axotomy), which affects not only neurons, but surrounding glia as well. Not only mechanically injured glia near the site of disconnection, especially transection, is subjected to the damage, but also glia that is remote from the lesion site. Glial cells, which surround the neuronal body, in turn, support neuron survival, so there is a mutual protection between neuron and glia. Calcium signaling is a central mediator of all post-axotomy events, both in neuron and glia, playing a critical role in their survival/regeneration or death/degeneration. The involvement of calcium in post-axotomy survival of the remote, mechanically intact glia is poorly studied. The purpose of this review is to sum up the calcium-involving mechanisms in responses of neurons and glial cells to axotomy to show their importance and to give some suggestions for future research of remote glia in this context.
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Affiliation(s)
- Andrey Khaitin
- Academy of Biology and Biotechnology, Southern Federal University, 344090 Rostov-on-Don, Russia
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4
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Skrzymowska J, Zalas M, Goszczyński TM, Miazek A. An alpha II spectrin mutant peptide with unstable scaffold structure and increased sensitivity to calpain cleavage. Biochem Biophys Res Commun 2021; 581:68-73. [PMID: 34656850 DOI: 10.1016/j.bbrc.2021.10.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 10/05/2021] [Indexed: 10/20/2022]
Abstract
A spontaneous missense mutation in the alpha II spectrin (αII) gene, replacing a highly conserved arginine 1098 with the glutamine (R1098Q), causes progressive neurodegeneration in heterozygous mutant mice. The molecular mechanism underlying this phenotype is unknown but the accumulation of 150kD αII breakdown products in brains of homozygous mutant embryos suggests an imbalance in the substrate level control of αII cleavage by calpains. This is further supported by in silico simulation predicting unmasked calpain target site and increased spectrin scaffold bending and flexibility of R1098Q mutant peptide. Here, using spectroscopic and in situ enzymatic techniques, we aimed at obtaining direct experimental support for the impact of R1098Q mutation on the αII stability and its propensity for calpain-mediated degradation. Thermal circular dichroism analyses performed on recombinant wildtype and R1098Q mutant αII peptides, composed of spectrin repeat 9-10 revealed that although both had very similar secondary structure contents, thermal stability curve profiles varied and the observed midpoint of the unfolding transition (Tm) was 5.5 °C lower for the R1098Q peptide. Yet, the dynamic light scattering profiles of both peptides closely overlapped, implying the same thermal propensity to aggregate. Calpain digestion of plate-bound αII peptides with and without added calmodulin revealed an enhancement of the R1098Q peptide digestion rate relative to WT control. In summary, these results support the unstable scaffold structure of the R1098Q peptide as contributing to its enhanced intrinsic sensitivity to calpain and suggest physiologic relevance of a proper calpain/spectrin balance in preventing neurodegeneration.
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Affiliation(s)
- Joanna Skrzymowska
- Department of Tumor Immunology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114, Wroclaw, Poland
| | - Michał Zalas
- Department of Tumor Immunology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114, Wroclaw, Poland
| | - Tomasz M Goszczyński
- Department of Experimental Oncology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114, Wroclaw, Poland
| | - Arkadiusz Miazek
- Department of Tumor Immunology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla 12, 53-114, Wroclaw, Poland.
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5
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Rudkovskii MV, Fedorenko AG, Khaitin AM, Pitinova MA, Uzdensky AB. The effect of axotomy on firing and ultrastructure of the crayfish mechanoreceptor neurons and satellite glial cells. Mol Cell Neurosci 2020; 107:103534. [PMID: 32717316 DOI: 10.1016/j.mcn.2020.103534] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/15/2020] [Accepted: 07/21/2020] [Indexed: 12/12/2022] Open
Abstract
Neurotrauma is among main causes of human disability and death. We studied effects of axotomy on ultrastructure and neuronal activity of a simple model object - an isolated crayfish stretch receptor that consists of single mechanoreceptor neurons (MRN) enwrapped by multilayer glial envelope. After isolation, MRN regularly fired until spontaneous activity cessation. Axotomy did not change significantly MRN spike amplitude and firing rate. However, the duration of neuron activity from MRN isolation to its spontaneous cessation decreased in axotomized MRN relative to intact neuron. [Ca2+] in MRN axon and soma increased 3-10 min after axotomy. Ca2+ entry through ion channels in the axolemma accelerated axotomy-stimulated firing cessation. MRN incubation with Ca2+ionophore ionomycin accelerated MRN inactivation, whereas Ca2+-channel blocker Cd2+ prolonged firing. Activity duration of either intact, or axotomized MRN did not change in the presence of ryanodine or dantrolene, inhibitors of ryanodin-sensitive Ca2+ channels in endoplasmic reticulum. Thapsigargin, inhibitor of endoplasmic reticulum Ca2+-ATPase, or its activator ochratoxin were ineffective. Ultrastructural study showed that the defect in the axon transected by thin scissors is sealed by fused axolemma, glial and collagen layers. Only the 30-50 μm long segment completely lost microtubules and contained swelled mitochondria. The microtubular bundle remained undamaged at 300 μm away from the axotomy site. However, mitochondria within the 200-300 μm segment were strongly condensed and lost matrix and cristae. Glial and collagen layers exhibited greater damage. Swelling and edema of glial layers, collagen disorganization and rupture occurred within this segment. Thus, axotomy stronger damages glia/collagen envelope, axonal microtubules and mitochondria.
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Affiliation(s)
- M V Rudkovskii
- Laboratory of Molecular Neurobiology, Southern Federal University, 194/1 Stachky ave., Rostov-on-Don 344090, Russia
| | - A G Fedorenko
- Laboratory of Molecular Neurobiology, Southern Federal University, 194/1 Stachky ave., Rostov-on-Don 344090, Russia
| | - A M Khaitin
- Laboratory of Molecular Neurobiology, Southern Federal University, 194/1 Stachky ave., Rostov-on-Don 344090, Russia
| | - M A Pitinova
- Laboratory of Molecular Neurobiology, Southern Federal University, 194/1 Stachky ave., Rostov-on-Don 344090, Russia
| | - A B Uzdensky
- Laboratory of Molecular Neurobiology, Southern Federal University, 194/1 Stachky ave., Rostov-on-Don 344090, Russia.
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6
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Shao X, Sørensen MH, Xia X, Fang C, Hui TH, Chang RCC, Chu Z, Lin Y. Beading of injured axons driven by tension- and adhesion-regulated membrane shape instability. J R Soc Interface 2020; 17:20200331. [PMCID: PMC7423423 DOI: 10.1098/rsif.2020.0331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 07/13/2020] [Indexed: 08/14/2023] Open
Abstract
The formation of multiple beads along an injured axon will lead to blockage of axonal transport and eventually neuron death, and this has been widely recognized as a hallmark of nervous system degeneration. Nevertheless, the underlying mechanisms remain poorly understood. Here, we report a combined experimental and theoretical study to reveal key factors governing axon beading. Specifically, by transecting well-developed axons with a sharp atomic force microscope probe, significant beading of the axons was triggered. We showed that adhesion was not required for beading to occur, although when present strong axon–substrate attachments seemed to set the locations for bead formation. In addition, the beading wavelength, representing the average distance between beads, was found to correlate with the size and cytoskeleton integrity of axon, with a thinner axon or a disrupted actin cytoskeleton both leading to a shorter beading wavelength. A model was also developed to explain these observations which suggest that axon beading originates from the shape instability of the membrane and is driven by the release of work done by axonal tension as well as the reduction of membrane surface energy. The beading wavelength predicted from this theory was in good agreement with our experiments under various conditions. By elucidating the essential physics behind axon beading, the current study could enhance our understanding of how axonal injury and neurodegeneration progress as well as provide insights for the development of possible treatment strategies.
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Affiliation(s)
- Xueying Shao
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, People's Republic of China
- HKU-Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong, People's Republic of China
| | - Maja Højvang Sørensen
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Xingyu Xia
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, People's Republic of China
- HKU-Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong, People's Republic of China
| | - Chao Fang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, People's Republic of China
- HKU-Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong, People's Republic of China
| | - Tsz Hin Hui
- Department of Electrical and Electronic Engineering, Joint Appointment with School of Biomedical Sciences, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Raymond Chuen Chung Chang
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Zhiqin Chu
- Department of Electrical and Electronic Engineering, Joint Appointment with School of Biomedical Sciences, The University of Hong Kong, Hong Kong, People's Republic of China
| | - Yuan Lin
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, People's Republic of China
- HKU-Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong, People's Republic of China
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7
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Smith TP, Sahoo PK, Kar AN, Twiss JL. Intra-axonal mechanisms driving axon regeneration. Brain Res 2020; 1740:146864. [PMID: 32360100 DOI: 10.1016/j.brainres.2020.146864] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 04/24/2020] [Accepted: 04/27/2020] [Indexed: 12/27/2022]
Abstract
Traumatic injury to the peripheral and central nervous systems very often causes axotomy, where an axon loses connections with its target resulting in loss of function. The axon segments distal to the injury site lose connection with the cell body and degenerate. Axotomized neurons in the periphery can spontaneously mount a regenerative response and reconnect to their denervated target tissues, though this is rarely complete in humans. In contrast, spontaneous regeneration rarely occurs after axotomy in the spinal cord and brain. Here, we concentrate on the mechanisms underlying this spontaneous regeneration in the peripheral nervous system, focusing on events initiated from the axon that support regenerative growth. We contrast this with what is known for axonal injury responses in the central nervous system. Considering the neuropathy focus of this special issue, we further draw parallels and distinctions between the injury-response mechanisms that initiate regenerative gene expression programs and those that are known to trigger axon degeneration.
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Affiliation(s)
- Terika P Smith
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Pabitra K Sahoo
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Amar N Kar
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA.
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8
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Abstract
Axons functionally link the somato-dendritic compartment to synaptic terminals. Structurally and functionally diverse, they accomplish a central role in determining the delays and reliability with which neuronal ensembles communicate. By combining their active and passive biophysical properties, they ensure a plethora of physiological computations. In this review, we revisit the biophysics of generation and propagation of electrical signals in the axon and their dynamics. We further place the computational abilities of axons in the context of intracellular and intercellular coupling. We discuss how, by means of sophisticated biophysical mechanisms, axons expand the repertoire of axonal computation, and thereby, of neural computation.
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Affiliation(s)
- Pepe Alcami
- Division of Neurobiology, Department of Biology II, Ludwig-Maximilians-Universitaet Muenchen, Martinsried, Germany
- Department of Behavioural Neurobiology, Max Planck Institute for Ornithology, Seewiesen, Germany
| | - Ahmed El Hady
- Princeton Neuroscience Institute, Princeton University, Princeton, NJ, United States
- Howard Hughes Medical Institute, Princeton University, Princeton, NJ, United States
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9
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Datar A, Ameeramja J, Bhat A, Srivastava R, Mishra A, Bernal R, Prost J, Callan-Jones A, Pullarkat PA. The Roles of Microtubules and Membrane Tension in Axonal Beading, Retraction, and Atrophy. Biophys J 2019; 117:880-891. [PMID: 31427070 DOI: 10.1016/j.bpj.2019.07.046] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 06/23/2019] [Accepted: 07/26/2019] [Indexed: 02/02/2023] Open
Abstract
Axonal beading, or the formation of a series of swellings along the axon, and retraction are commonly observed shape transformations that precede axonal atrophy in Alzheimer's disease, Parkinson's disease, and other neurodegenerative conditions. The mechanisms driving these morphological transformations are poorly understood. Here, we report controlled experiments that can induce either beading or retraction and follow the time evolution of these responses. By making quantitative analysis of the shape modes under different conditions, measurement of membrane tension, and using theoretical considerations, we argue that membrane tension is the main driving force that pushes cytosol out of the axon when microtubules are degraded, causing axonal thinning. Under pharmacological perturbation, atrophy is always retrograde, and this is set by a gradient in the microtubule stability. The nature of microtubule depolymerization dictates the type of shape transformation, vis-à-vis beading or retraction. Elucidating the mechanisms of these shape transformations may facilitate development of strategies to prevent or arrest axonal atrophy due to neurodegenerative conditions.
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Affiliation(s)
| | | | - Alka Bhat
- Raman Research Institute, Bengaluru, India
| | | | | | - Roberto Bernal
- Departamento de Física, SMAT-C, Universidad de Santiago de Chile, Santiago, Chile
| | - Jacques Prost
- Laboratoire Physico Chimie Curie, Institut Curie, 10 PSL Research University, CNRS UMR168, Paris, France; Mechanobiology Institute, National University of Singapore, Singapore
| | - Andrew Callan-Jones
- Laboratoire Matière et Systèmes Complexes, Université Paris Diderot, Paris, France.
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10
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Rink S, Bendella H, Akkin SM, Manthou M, Grosheva M, Angelov DN. Experimental Studies on Facial Nerve Regeneration. Anat Rec (Hoboken) 2019; 302:1287-1303. [DOI: 10.1002/ar.24123] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 10/09/2018] [Accepted: 11/02/2018] [Indexed: 12/20/2022]
Affiliation(s)
- Svenja Rink
- Department of Prosthetic Dentistry, School of Dental and Oral MedicineUniversity of Cologne Cologne Germany
| | - Habib Bendella
- Department of NeurosurgeryUniversity of Witten/Herdecke, Cologne Merheim Medical Center (CMMC) Cologne Germany
| | - Salih Murat Akkin
- Department of Anatomy, School of MedicineSANKO University Gaziantep Turkey
| | - Marilena Manthou
- Department of Histology and EmbryologyAristotle University Thessaloniki Thessaloniki Greece
| | - Maria Grosheva
- Department of Oto‐Rhino‐LaryngologyUniversity of Cologne Cologne Germany
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11
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Schaffran B, Hilton BJ, Bradke F. Imaging in vivo dynamics of sensory axon responses to CNS injury. Exp Neurol 2019; 317:110-118. [PMID: 30794766 DOI: 10.1016/j.expneurol.2019.02.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 02/13/2019] [Accepted: 02/17/2019] [Indexed: 01/25/2023]
Abstract
Axons in the adult mammalian brain and spinal cord fail to regenerate upon lesion. In vivo imaging serves as a tool to investigate the immediate response of axons to injury and how the same injured axons behave over time. Here, we describe the dynamic changes that injured sensory axons undergo and methods of imaging them in vivo. First, we explain how sensory axons in the dorsal column of the adult mouse spinal cord respond to axotomy. Then, we highlight practical considerations for implementing two-photon based in vivo imaging of these axons. Finally, we describe future directions for this technique, including the possibility of in vivo imaging of subcellular dynamics within the axon.
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Affiliation(s)
| | - Brett J Hilton
- German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Frank Bradke
- German Center for Neurodegenerative Diseases, Bonn, Germany.
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12
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Pham VM, Matsumura S, Katano T, Funatsu N, Ito S. Diabetic neuropathy research: from mouse models to targets for treatment. Neural Regen Res 2019; 14:1870-1879. [PMID: 31290436 PMCID: PMC6676867 DOI: 10.4103/1673-5374.259603] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Diabetic neuropathy is one of the most serious complications of diabetes, and its increase shows no sign of stopping. Furthermore, current clinical treatments do not yet approach the best effectiveness. Thus, the development of better strategies for treating diabetic neuropathy is an urgent matter. In this review, we first discuss the advantages and disadvantages of some major mouse models of diabetic neuropathy and then address the targets for mechanism-based treatment that have been studied. We also introduce our studies on each part. Using stem cells as a source of neurotrophic factors to target extrinsic factors of diabetic neuropathy, we found that they present a promising treatment.
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Affiliation(s)
- Vuong M Pham
- Department of Medical Chemistry, Kansai Medical University, Hirakata, Osaka, Japan; Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, Singapore
| | - Shinji Matsumura
- Department of Medical Chemistry, Kansai Medical University, Hirakata, Osaka, Japan
| | - Tayo Katano
- Department of Medical Chemistry, Kansai Medical University, Hirakata, Osaka, Japan
| | - Nobuo Funatsu
- Department of Medical Chemistry, Kansai Medical University, Hirakata, Osaka, Japan
| | - Seiji Ito
- Department of Medical Chemistry, Kansai Medical University, Hirakata; Department of Anesthesiology, Osaka Medical College, Takatsuki, Osaka, Japan
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13
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Girouard MP, Bueno M, Julian V, Drake S, Byrne AB, Fournier AE. The Molecular Interplay between Axon Degeneration and Regeneration. Dev Neurobiol 2018; 78:978-990. [PMID: 30022605 DOI: 10.1002/dneu.22627] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 05/29/2018] [Accepted: 06/04/2018] [Indexed: 12/30/2022]
Abstract
Neurons face a series of morphological and molecular changes following trauma and in the progression of neurodegenerative disease. In neurons capable of mounting a spontaneous regenerative response, including invertebrate neurons and mammalian neurons of the peripheral nervous system (PNS), axons regenerate from the proximal side of the injury and degenerate on the distal side. Studies of Wallerian degeneration slow (WldS /Ola) mice have revealed that a level of coordination between the processes of axon regeneration and degeneration occurs during successful repair. Here, we explore how shared cellular and molecular pathways that regulate both axon regeneration and degeneration coordinate the two distinct outcomes in the proximal and distal axon segments. © 2018 Wiley Periodicals, Inc. Develop Neurobiol 00: 000-000, 2018.
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Affiliation(s)
- Marie-Pier Girouard
- Department of Neurology & Neurosurgery, Montréal Neurological Institute, Montréal, Quebec H3A 2B4, Canada
| | - Mardja Bueno
- Department of Neurology & Neurosurgery, Montréal Neurological Institute, Montréal, Quebec H3A 2B4, Canada
| | - Victoria Julian
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Sienna Drake
- Department of Neurology & Neurosurgery, Montréal Neurological Institute, Montréal, Quebec H3A 2B4, Canada
| | - Alexandra B Byrne
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Alyson E Fournier
- Department of Neurology & Neurosurgery, Montréal Neurological Institute, Montréal, Quebec H3A 2B4, Canada
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14
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Chen L. Microtubules and axon regeneration in C. elegans. Mol Cell Neurosci 2018; 91:160-166. [PMID: 29551667 DOI: 10.1016/j.mcn.2018.03.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 03/14/2018] [Accepted: 03/15/2018] [Indexed: 11/28/2022] Open
Abstract
Axon regeneration is a fundamental and conserved process that allows the nervous system to repair circuits after trauma. Due to its conserved genome, transparent body, and relatively simple neuroanatomy, C. elegans has become a powerful model organism for studying the cellular and molecular mechanisms underlying axon regeneration. Various studies from different model organisms have found microtubule dynamics to be pivotal to axon regrowth. In this review, we will discuss the latest findings on how microtubule dynamics are regulated during axon regeneration in C. elegans. Understanding the mechanisms of axon regeneration will aid in the development of more effective therapeutic strategies for treatments of diseases involving disconnection of axons, such as spinal cord injury and stroke.
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Affiliation(s)
- Lizhen Chen
- Barshop Institute for Longevity and Aging Studies, Department of Cell Systems and Anatomy, Department of Molecular Medicine, University of Texas Health Science Center San Antonio, San Antonio, TX, USA.
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15
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Filous AR, Schwab JM. Determinants of Axon Growth, Plasticity, and Regeneration in the Context of Spinal Cord Injury. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 188:53-62. [PMID: 29030051 DOI: 10.1016/j.ajpath.2017.09.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 09/15/2017] [Accepted: 09/21/2017] [Indexed: 12/30/2022]
Abstract
The mechanisms that underlie recovery after injury of the central nervous system have rarely been definitively established. Axon regrowth remains the major prerequisite for plasticity, regeneration, circuit formation, and eventually functional recovery. The attributed functional relevance of axon regrowth, however, will depend on several subsequent conditional neurobiological modifications, including myelination and synapse formation, but also pruning of aberrant connectivity. Despite the ability to revamp axon outgrowth by altering an increasing number of extracellular and intracellular targets, disentangling which axons are responsible for the recovery of function from those that are functionally silent, or even contributing to aberrant functions, represents a pertinent void in our understanding, challenging the intuitive translational link between anatomical and functional regeneration. Anatomic hallmarks of regeneration are not static and are largely activity dependent. Herein, we survey mechanisms leading to the formation of dystrophic growth cone at the injured axonal tip, the subsequent axonal dieback, and the molecular determinants of axon growth, plasticity, and regeneration in the context of spinal cord injury.
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Affiliation(s)
- Angela R Filous
- Spinal Cord Injury Division, Department of Neurology, The Ohio State University, Wexner Medical Center, Columbus, Ohio.
| | - Jan M Schwab
- Spinal Cord Injury Division, Department of Neurology, The Ohio State University, Wexner Medical Center, Columbus, Ohio; Department of Neuroscience, The Ohio State University, Wexner Medical Center, Columbus, Ohio; Department of Physical Medicine and Rehabilitation, The Ohio State University, Wexner Medical Center, Columbus, Ohio; Center for Brain and Spinal Cord Repair, Spinal Cord Injury Medicine, The Ohio State University, Wexner Medical Center, Columbus, Ohio.
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16
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Zhang JN, Michel U, Lenz C, Friedel CC, Köster S, d’Hedouville Z, Tönges L, Urlaub H, Bähr M, Lingor P, Koch JC. Calpain-mediated cleavage of collapsin response mediator protein-2 drives acute axonal degeneration. Sci Rep 2016; 6:37050. [PMID: 27845394 PMCID: PMC5109185 DOI: 10.1038/srep37050] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 10/24/2016] [Indexed: 01/25/2023] Open
Abstract
Axonal degeneration is a key initiating event in many neurological diseases. Focal lesions to axons result in a rapid disintegration of the perilesional axon by acute axonal degeneration (AAD) within several hours. However, the underlying molecular mechanisms of AAD are only incompletely understood. Here, we studied AAD in vivo through live-imaging of the rat optic nerve and in vitro in primary rat cortical neurons in microfluidic chambers. We found that calpain is activated early during AAD of the optic nerve and that calpain inhibition completely inhibits axonal fragmentation on the proximal side of the crush while it attenuates AAD on the distal side. A screening of calpain targets revealed that collapsin response mediator protein-2 (CRMP2) is a main downstream target of calpain activation in AAD. CRMP2-overexpression delayed bulb formation and rescued impairment of axonal mitochondrial transport after axotomy in vitro. In vivo, CRMP2-overexpression effectively protected the proximal axon from fragmentation within 6 hours after crush. Finally, a proteomic analysis of the optic nerve was performed at 6 hours after crush, which identified further proteins regulated during AAD, including several interactors of CRMP2. These findings reveal CRMP2 as an important mediator of AAD and define it as a putative therapeutic target.
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Affiliation(s)
- Jian-Nan Zhang
- Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
| | - Uwe Michel
- Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
| | - Christof Lenz
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
- Institute of Clinical Chemistry, University Medicine Göttingen, 37075 Göttingen, Germany
| | | | - Sarah Köster
- Institute for X-Ray Physics, Georg-August-University Göttingen, 37077 Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37075 Göttingen, Germany
| | - Zara d’Hedouville
- Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
| | - Lars Tönges
- Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
- Department of Neurology, Ruhr-University Bochum, St. Josef-Hospital, 44791 Bochum, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
- Institute of Clinical Chemistry, University Medicine Göttingen, 37075 Göttingen, Germany
| | - Mathias Bähr
- Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37075 Göttingen, Germany
| | - Paul Lingor
- Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37075 Göttingen, Germany
| | - Jan C. Koch
- Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37075 Göttingen, Germany
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Multisite electrophysiological recordings by self-assembled loose-patch-like junctions between cultured hippocampal neurons and mushroom-shaped microelectrodes. Sci Rep 2016; 6:27110. [PMID: 27256971 PMCID: PMC4891817 DOI: 10.1038/srep27110] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 05/12/2016] [Indexed: 11/25/2022] Open
Abstract
Substrate integrated planar microelectrode arrays is the “gold standard” method for millisecond-resolution, long-term, large-scale, cell-noninvasive electrophysiological recordings from mammalian neuronal networks. Nevertheless, these devices suffer from drawbacks that are solved by spike-detecting, spike-sorting and signal-averaging techniques which rely on estimated parameters that require user supervision to correct errors, merge clusters and remove outliers. Here we show that primary rat hippocampal neurons grown on micrometer sized gold mushroom-shaped microelectrodes (gMμE) functionalized simply by poly-ethylene-imine/laminin undergo self-assembly processes to form loose patch-like hybrid structures. More than 90% of the hybrids formed in this way record monophasic positive action potentials (APs). Of these, 34.5% record APs with amplitudes above 300 μV and up to 5,085 μV. This self-assembled neuron-gMμE configuration improves the recording quality as compared to planar MEA. This study characterizes and analyzes the electrophysiological signaling repertoire generated by the neurons-gMμE configuration, and discusses prospects to further improve the technology.
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Voelker P, Piscopo D, Weible AP, Lynch G, Rothbart MK, Posner MI, Niell CM. How changes in white matter might underlie improved reaction time due to practice. Cogn Neurosci 2016; 8:112-118. [PMID: 27064751 DOI: 10.1080/17588928.2016.1173664] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Why does training on a task reduce the reaction time for performing it? New research points to changes in white matter pathways as one likely mechanism. These pathways connect remote brain areas involved in performing the task. Genetic variations may be involved in individual differences in the extent of this improvement. If white matter change is involved in improved reaction time with training, it may point the way toward understanding where and how generalization occurs. We examine the hypothesis that brain pathways shared by different tasks may result in improved performance of cognitive tasks remote from the training.
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Affiliation(s)
- Pascale Voelker
- a Department of Psychology , University of Oregon , Eugene , OR , USA
| | - Denise Piscopo
- b Department of Biology , University of Oregon , Eugene , OR , USA
| | - Aldis P Weible
- b Department of Biology , University of Oregon , Eugene , OR , USA.,c Institute of Neuroscience , University of Oregon , Eugene , OR , USA
| | - Gary Lynch
- d Department of Neurobiology and Behavior UC Irvine , Irvine , CA , USA
| | - Mary K Rothbart
- a Department of Psychology , University of Oregon , Eugene , OR , USA
| | - Michael I Posner
- a Department of Psychology , University of Oregon , Eugene , OR , USA.,c Institute of Neuroscience , University of Oregon , Eugene , OR , USA
| | - Cristopher M Niell
- b Department of Biology , University of Oregon , Eugene , OR , USA.,c Institute of Neuroscience , University of Oregon , Eugene , OR , USA
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19
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Wang X, Chen T, Zhang Y, Li B, Xu Q, Song C. Isolation and Culture of Pig Spermatogonial Stem Cells and Their in Vitro Differentiation into Neuron-Like Cells and Adipocytes. Int J Mol Sci 2015; 16:26333-46. [PMID: 26556335 PMCID: PMC4661817 DOI: 10.3390/ijms161125958] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Revised: 10/21/2015] [Accepted: 10/23/2015] [Indexed: 12/14/2022] Open
Abstract
Spermatogonial stem cells (SSCs) renew themselves throughout the life of an organism and also differentiate into sperm in the adult. They are multipopent and therefore, can be induced to differentiate into many cells types in vitro. SSCs from pigs, considered an ideal animal model, are used in studies of male infertility, regenerative medicine, and preparation of transgenic animals. Here, we report on a culture system for porcine SSCs and the differentiation of these cells into neuron-like cells and adipocytes. SSCs and Sertoli cells were isolated from neonatal piglet testis by differential adhesion and SSCs were cultured on a feeder layer of Sertoli cells. Third-generation SSCs were induced to differentiate into neuron-like cells by addition of retinoic acid, β-mercaptoethanol, and 3-isobutyl-1-methylxanthine (IBMX) to the induction media and into adipocytes by the addition of hexadecadrol, insulin, and IBMX to the induction media. The differentiated cells were characterized by biochemical staining, qRT-PCR, and immunocytochemistry. The cells were positive for SSC markers, including alkaline phosphatase and SSC-specific genes, consistent with the cells being undifferentiated. The isolated SSCs survived on the Sertoli cells for 15 generations. Karyotyping confirmed that the chromosomal number of the SSCs were normal for pig (2n = 38, n = 19). Pig SSCs were successfully induced into neuron-like cells eight days after induction and into adipocytes 22 days after induction as determined by biochemical and immunocytochemical staining. qPCR results also support this conclusion. The nervous tissue markers genes, Nestin and β-tubulin, were expressed in the neuron-like cells and the adipocyte marker genes, PPARγ and C/EBPα, were expressed in the adipocytes.
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Affiliation(s)
- Xiaoyan Wang
- College of Animal Science & Technology, Yangzhou University, Yangzhou 225009, China.
| | - Tingfeng Chen
- College of Animal Science & Technology, Yangzhou University, Yangzhou 225009, China.
| | - Yani Zhang
- College of Animal Science & Technology, Yangzhou University, Yangzhou 225009, China.
| | - Bichun Li
- College of Animal Science & Technology, Yangzhou University, Yangzhou 225009, China.
| | - Qi Xu
- College of Animal Science & Technology, Yangzhou University, Yangzhou 225009, China.
| | - Chengyi Song
- College of Animal Science & Technology, Yangzhou University, Yangzhou 225009, China.
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20
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A feasibility study of multi-site,intracellular recordings from mammalian neurons by extracellular gold mushroom-shaped microelectrodes. Sci Rep 2015; 5:14100. [PMID: 26365404 PMCID: PMC4568476 DOI: 10.1038/srep14100] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 08/18/2015] [Indexed: 01/20/2023] Open
Abstract
The development of multi-electrode array platforms for large scale recording of neurons is at the forefront of neuro-engineering research efforts. Recently we demonstrated, at the proof-of-concept level, a breakthrough neuron-microelectrode interface in which cultured Aplysia neurons tightly engulf gold mushroom-shaped microelectrodes (gMμEs). While maintaining their extracellular position, the gMμEs record synaptic- and action-potentials with characteristic features of intracellular recordings. Here we examined the feasibility of using gMμEs for intracellular recordings from mammalian neurons. To that end we experimentally examined the innate size limits of cultured rat hippocampal neurons to engulf gMμEs and measured the width of the “extracellular” cleft formed between the neurons and the gold surface. Using the experimental results we next analyzed the expected range of gMμEs-neuron electrical coupling coefficients. We estimated that sufficient electrical coupling levels to record attenuated synaptic- and action-potentials can be reached using the gMμE-neuron configuration. The definition of the engulfment limits of the gMμEs caps diameter at ≤2–2.5 μm and the estimated electrical coupling coefficients from the simulations pave the way for rational development and application of the gMμE based concept for in-cell recordings from mammalian neurons.
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Abstract
Peripheral axonal regeneration requires surface-expanding membrane addition. The continuous incorporation of new membranes into the axolemma allows the pushing force of elongating microtubules to drive axonal growth cones forwards. Hence, a constant supply of membranes and cytoskeletal building blocks is required, often for many weeks. In human peripheral nerves, axonal tips may be more than 1 m away from the neuronal cell body. Therefore, in the initial phase of regeneration, membranes are derived from pre-existing vesicles or synthesised locally. Only later stages of axonal regeneration are supported by membranes and proteins synthesised in neuronal cell bodies, considering that the fastest anterograde transport mechanisms deliver cargo at 20 cm/day. Whereas endocytosis and exocytosis of membrane vesicles are balanced in intact axons, membrane incorporation exceeds membrane retrieval during regeneration to compensate for the loss of membranes distal to the lesion site. Physiological membrane turnover rates will not be established before the completion of target reinnervation. In this review, the current knowledge on membrane traffic in axonal outgrowth is summarised, with a focus on endosomal vesicles as the providers of membranes and carriers of growth factor receptors required for initiating signalling pathways to promote the elongation and branching of regenerating axons in lesioned peripheral nerves.
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Affiliation(s)
- Barbara Hausott
- Division of Neuroanatomy, Department of Anatomy, Histology and Embryology, Medical University Innsbruck, 6020, Innsbruck, Austria
| | - Lars Klimaschewski
- Division of Neuroanatomy, Department of Anatomy, Histology and Embryology, Medical University Innsbruck, 6020, Innsbruck, Austria
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22
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Posner MI, Tang YY, Lynch G. Mechanisms of white matter change induced by meditation training. Front Psychol 2014; 5:1220. [PMID: 25386155 PMCID: PMC4209813 DOI: 10.3389/fpsyg.2014.01220] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 10/08/2014] [Indexed: 12/12/2022] Open
Abstract
Training can induce changes in specific brain networks and changes in brain state. In both cases it has been found that the efficiency of white matter as measured by diffusion tensor imaging is increased, often after only a few hours of training. In this paper we consider a plausible molecular mechanism for how state change produced by meditation might lead to white matter change. According to this hypothesis frontal theta induced by meditation produces a molecular cascade that increases myelin and improves connectivity.
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Affiliation(s)
| | - Yi-Yuan Tang
- Department of Psychological Sciences, Texas Tech University Lubbock, TX, USA
| | - Gary Lynch
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine Irvine, CA, USA
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23
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Ojovan SM, McDonald M, McDonald M, Rabieh N, Shmuel N, Erez H, Nesladek M, Spira ME. Nanocrystalline diamond surfaces for adhesion and growth of primary neurons, conflicting results and rational explanation. FRONTIERS IN NEUROENGINEERING 2014; 7:17. [PMID: 24966832 PMCID: PMC4052739 DOI: 10.3389/fneng.2014.00017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 05/23/2014] [Indexed: 02/05/2023]
Abstract
Using a variety of proliferating cell types, it was shown that the surface of nanocrystalline diamond (NCD) provides a permissive substrate for cell adhesion and development without the need of complex chemical functionalization prior to cell seeding. In an extensive series of experiments we found that, unlike proliferating cells, post-mitotic primary neurons do not adhere to bare NCD surfaces when cultured in defined medium. These observations raise questions on the potential use of bare NCD as an interfacing layer for neuronal devices. Nevertheless, we also found that classical chemical functionalization methods render the “hostile” bare NCD surfaces with adhesive properties that match those of classically functionalized substrates used extensively in biomedical research and applications. Based on the results, we propose a mechanism that accounts for the conflicting results; which on one hand claim that un-functionalized NCD provides a permissive substrate for cell adhesion and growth, while other reports demonstrate the opposite.
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Affiliation(s)
- Silviya M Ojovan
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem Jerusalem, Israel
| | - Matthew McDonald
- Institute for Materials Research in MicroElectronics - Interuniversity Micro Electronics Centre, Hasselt University Antwerp, Belgium
| | | | - Noha Rabieh
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem Jerusalem, Israel
| | - Nava Shmuel
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem Jerusalem, Israel ; The Harvy M. Kruger Family Center for Nanoscience, The Hebrew University of Jerusalem Jerusalem, Israel
| | - Hadas Erez
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem Jerusalem, Israel
| | - Milos Nesladek
- Institute for Materials Research in MicroElectronics - Interuniversity Micro Electronics Centre, Hasselt University Antwerp, Belgium
| | - Micha E Spira
- Department of Neurobiology, The Alexander Silberman Institute of Life Science, The Hebrew University of Jerusalem Jerusalem, Israel ; The Harvy M. Kruger Family Center for Nanoscience, The Hebrew University of Jerusalem Jerusalem, Israel
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24
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Lu Y, Belin S, He Z. Signaling regulations of neuronal regenerative ability. Curr Opin Neurobiol 2014; 27:135-42. [PMID: 24727245 DOI: 10.1016/j.conb.2014.03.007] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 03/13/2014] [Accepted: 03/14/2014] [Indexed: 10/25/2022]
Abstract
Different from physiological axon growth during development, a major limiting factor for successful axon regeneration is the poor intrinsic regenerative capacity in mature neurons in the adult mammalian central nervous system (CNS). Recent studies identified several molecular pathways, including PTEN/mTOR, Jak/STAT, DLK/JNK, providing important probes in investigating the mechanisms by which the regenerative ability is regulated. This review will summarize these recent findings and speculate their implications.
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Affiliation(s)
- Yi Lu
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; F.M. Kirby Neurobiology Center, Boston Children's Hospital, and Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Stéphane Belin
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, and Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Zhigang He
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, and Department of Neurology, Harvard Medical School, Boston, MA 02115, USA.
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25
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Neu3 sialidase-mediated ganglioside conversion is necessary for axon regeneration and is blocked in CNS axons. J Neurosci 2014; 34:2477-92. [PMID: 24523539 DOI: 10.1523/jneurosci.4432-13.2014] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
PNS axons have a high intrinsic regenerative ability, whereas most CNS axons show little regenerative response. We show that activation of Neu3 sialidase, also known as Neuraminidase-3, causing conversion of GD1a and GT1b to GM1 ganglioside, is an essential step in regeneration occurring in PNS (sensory) but not CNS (retinal) axons in adult rat. In PNS axons, axotomy activates Neu3 sialidase, increasing the ratio of GM1/GD1a and GM1/GT1b gangliosides immediately after injury in vitro and in vivo. No change in the GM1/GD1a ratio after axotomy was observed in retinal axons (in vitro and in vivo), despite the presence of Neu3 sialidase. Externally applied sialidase converted GD1a ganglioside to GM1 and rescued axon regeneration in CNS axons and in PNS axons after Neu3 sialidase blockade. Neu3 sialidase activation in DRGs is initiated by an influx of extracellular calcium, activating P38MAPK and then Neu3 sialidase. Ganglioside conversion by Neu3 sialidase further activates the ERK pathway. In CNS axons, P38MAPK and Neu3 sialidase were not activated by axotomy.
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Abstract
Axons of the mammalian CNS lose the ability to regenerate soon after development due to both an inhibitory CNS environment and the loss of cell-intrinsic factors necessary for regeneration. The complex molecular events required for robust regeneration of mature neurons are not fully understood, particularly in vivo. To identify genes affecting axon regeneration in Caenorhabditis elegans, we performed both an RNAi-based screen for defective motor axon regeneration in unc-70/β-spectrin mutants and a candidate gene screen. From these screens, we identified at least 50 conserved genes with growth-promoting or growth-inhibiting functions. Through our analysis of mutants, we shed new light on certain aspects of regeneration, including the role of β-spectrin and membrane dynamics, the antagonistic activity of MAP kinase signaling pathways, and the role of stress in promoting axon regeneration. Many gene candidates had not previously been associated with axon regeneration and implicate new pathways of interest for therapeutic intervention.
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27
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Prokosch V, Chiwitt C, Rose K, Thanos S. Deciphering proteins and their functions in the regenerating retina. Expert Rev Proteomics 2014; 7:775-95. [DOI: 10.1586/epr.10.47] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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28
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Abstract
Axon regeneration after damage is widespread in the animal kingdom, and the nematode Caenorhabditis elegans has recently emerged as a tractable model in which to study the genetics and cell biology of axon regrowth in vivo. A key early step in axon regrowth is the conversion of part of a mature axon shaft into a growth cone-like structure, involving coordinated alterations in the microtubule, actin, and neurofilament systems. Recent attention has focused on microtubule dynamics as a determinant of axon-regrowth ability in several organisms. Live imaging studies have begun to reveal how the microtubule cytoskeleton is remodeled after axon injury, as well as the regulatory pathways involved. The dual leucine zipper kinase family of mixed-lineage kinases has emerged as a critical sensor of axon damage and plays a key role in regulating microtubule dynamics in the damaged axon.
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Affiliation(s)
- Andrew D Chisholm
- Division of Biological Sciences, Section of Neurobiology, University of California, San Diego, La Jolla, California 92093;
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29
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Grumbles RM, Liu Y, Thomas CM, Wood PM, Thomas CK. Acute stimulation of transplanted neurons improves motoneuron survival, axon growth, and muscle reinnervation. J Neurotrauma 2013; 30:1062-9. [PMID: 23544978 PMCID: PMC3689928 DOI: 10.1089/neu.2012.2797] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Few options exist for treatment of pervasive motoneuron death after spinal cord injury or in neurodegenerative diseases such as amyotrophic lateral sclerosis. Local transplantation of embryonic motoneurons into an axotomized peripheral nerve is a promising approach to arrest the atrophy of denervated muscles; however, muscle reinnervation is limited by poor motoneuron survival. The aim of the present study was to test whether acute electrical stimulation of transplanted embryonic neurons promotes motoneuron survival, axon growth, and muscle reinnervation. The sciatic nerve of adult Fischer rats was transected to mimic the widespread denervation seen after disease or injury. Acutely dissociated rat embryonic ventral spinal cord cells were transplanted into the distal tibial nerve stump as a neuron source for muscle reinnervation. Immediately post-transplantation, the cells were stimulated at 20 Hz for 1 h. Other groups were used to control for the cell transplantation and stimulation. When neurons were stimulated acutely, there were significantly more neurons, including cholinergic neurons, 10 weeks after transplantation. This led to enhanced numbers of myelinated axons, reinnervation of more muscle fibers, and more medial and lateral gastrocnemius muscles were functionally connected to the transplant. Reinnervation reduced muscle atrophy significantly. These data support the concept that electrical stimulation rescues transplanted motoneurons and facilitates muscle reinnervation.
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Affiliation(s)
- Robert M. Grumbles
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, Florida
| | - Yang Liu
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, Florida
| | - Christie M. Thomas
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, Florida
| | - Patrick M. Wood
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, Florida
| | - Christine K. Thomas
- The Miami Project to Cure Paralysis, Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, Florida
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, Florida
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30
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Klimaschewski L, Hausott B, Angelov DN. The pros and cons of growth factors and cytokines in peripheral axon regeneration. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2013; 108:137-71. [PMID: 24083434 DOI: 10.1016/b978-0-12-410499-0.00006-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Injury to a peripheral nerve induces a complex cellular and molecular response required for successful axon regeneration. Proliferating Schwann cells organize into chains of cells bridging the lesion site, which is invaded by macrophages. Approximately half of the injured neuron population sends out axons that enter the glial guidance channels in response to secreted neurotrophic factors and neuropoietic cytokines. These lesion-associated polypeptides create an environment that is highly supportive for axon regrowth, particularly after acute injury, and ensure that the vast majority of regenerating axons are directed toward the distal nerve stump. Unfortunately, most neurotrophic factors and neuropoietic cytokines are also strong stimulators of axonal sprouting. Although some of the axonal branches will withdraw at later stages, the sprouting effect contributes to the misdirection of reinnervation that results in the lack of functional recovery observed in many patients with peripheral nerve injuries. Here, we critically review the role of neuronal growth factors and cytokines during axon regeneration in the peripheral nervous system. Their differential effects on axon elongation and sprouting were elucidated in various studies on intraneuronal signaling mechanisms following nerve lesion. The present data define a goal for future therapeutic strategies, namely, to selectively stimulate a Ras/Raf/ERK-mediated axon elongation program over an intrinsic PI3K-dependent axonal sprouting program in lesioned motor and sensory neurons. Instead of modulating growth factor or cytokine levels at the lesion site, targeting specific intraneuronal molecules, such as the negative feedback inhibitors of ERK signaling, has been shown to promote long-distance regeneration while avoiding sprouting of regenerating axons until they have reached their target areas.
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Affiliation(s)
- Lars Klimaschewski
- Division of Neuroanatomy, Department of Anatomy and Histology, Innsbruck Medical University, Innsbruck, Austria
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31
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Cassereau J, Nicolas G, Lonchampt P, Pinier M, Barthelaix A, Eyer J, Letournel F. Axonal regeneration is compromised in NFH-LacZ transgenic mice but not in NFH-GFP mice. Neuroscience 2013; 228:101-8. [DOI: 10.1016/j.neuroscience.2012.10.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 10/04/2012] [Accepted: 10/04/2012] [Indexed: 11/26/2022]
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Abstract
Despite important progress made in understanding the mechanisms of axon regeneration, how a neuron responds to an injury and makes a regenerative decision remains unclear. In this issue of Genes & Development, Song and colleagues (pp. 1612-1625) investigate axonal and dendritic regeneration in the Drosophila peripheral nervous system (PNS). With some mechanisms shared with mammals, this study reveals surprisingly complicated regenerative responses in terms of cell type, developmental stage, and mechanism specificity. With forward genetic potential, such invertebrates should be powerful in dissecting the cellular and molecular control of neuronal repair.
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33
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Fendyur A, Spira ME. Toward on-chip, in-cell recordings from cultured cardiomyocytes by arrays of gold mushroom-shaped microelectrodes. FRONTIERS IN NEUROENGINEERING 2012; 5:21. [PMID: 22936913 PMCID: PMC3426852 DOI: 10.3389/fneng.2012.00021] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 08/05/2012] [Indexed: 11/13/2022]
Abstract
Cardiological research greatly rely on the use of cultured primary cardiomyocytes (CMs). The prime methodology to assess CM network electrophysiology is based on the use of extracellular recordings by substrate-integrated planar Micro-Electrode Arrays (MEAs). Whereas this methodology permits simultaneous, long-term monitoring of the CM electrical activity, it limits the information to extracellular field potentials (FPs). The alternative method of intracellular action potentials (APs) recordings by sharp- or patch-microelectrodes is limited to a single cell at a time. Here, we began to merge the advantages of planar MEA and intracellular microelectrodes. To that end we cultured rat CM on micrometer size protruding gold mushroom-shaped microelectrode (gMμEs) arrays. Cultured CMs engulf the gMμE permitting FPs recordings from individual cells. Local electroporation of a CM converts the extracellular recording configuration to attenuated intracellular APs with shape and duration similar to those recorded intracellularly. The procedure enables to simultaneously record APs from an unlimited number of CMs. The electroporated membrane spontaneously recovers. This allows for repeated recordings from the same CM a number of times (>8) for over 10 days. The further development of CM-gMμE configuration opens up new venues for basic and applied biomedical research.
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Affiliation(s)
- Anna Fendyur
- The Alexander Silberman Life Sciences Institute and the Harvey M. Kruger Family Center for Nanoscience, The Hebrew University of Jerusalem Jerusalem, Israel
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Kanamori A, Catrinescu MM, Belisle JM, Costantino S, Levin LA. Retrograde and Wallerian axonal degeneration occur synchronously after retinal ganglion cell axotomy. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 181:62-73. [PMID: 22642911 DOI: 10.1016/j.ajpath.2012.03.030] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Revised: 03/05/2012] [Accepted: 03/15/2012] [Indexed: 01/23/2023]
Abstract
Axonal injury and degeneration are pivotal pathological events in diseases of the nervous system. In the past decade, it has been recognized that the process of axonal degeneration is distinct from somal degeneration and that axoprotective strategies may be distinct from those that protect the soma. Preserving the cell body via neuroprotection cannot improve function if the axon is damaged, because the soma is still disconnected from its target. Therefore, understanding the mechanisms of axonal degeneration is critical for developing new therapeutic interventions for axonal disease treatment. We combined in vivo imaging with a multilaser confocal scanning laser ophthalmoscope and in vivo axotomy with a diode-pumped solid-state laser to assess the time course of Wallerian and retrograde degeneration of unmyelinated retinal ganglion cell axons in living rats for 4 weeks after intraretinal axotomy. Laser injury resulted in reproducible axon loss both distal and proximal to the site of injury. Longitudinal polarization-sensitive imaging of axons demonstrated that Wallerian and retrograde degeneration occurred synchronously. Neurofilament immunostaining of retinal whole-mounts confirmed axonal loss and demonstrated sparing of adjacent axons to the axotomy site. In vivo fluorescent imaging of axonal transport and photobleaching of labeled axons demonstrated that the laser axotomy model did not affect adjacent axon function. These results are consistent with a shared mechanism for Wallerian and retrograde degeneration.
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Affiliation(s)
- Akiyasu Kanamori
- Maisonneuve-Rosemont Hospital Research Center and Department of Ophthalmology, University of Montreal, Quebec, Canada
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35
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Oren R, Sfez R, Korbakov N, Shabtai K, Cohen A, Erez H, Dormann A, Cohen H, Shappir J, Spira ME, Yitzchaik S. Electrically conductive 2D-PAN-containing surfaces as a culturing substrate for neurons. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2012; 15:1355-74. [PMID: 15648568 DOI: 10.1163/1568562042368077] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In the present contribution we report on a novel route to synthesize 2D-polyaniline (2D-PAN) on sulfonated-poly(styrene) (SPS) templates by allowing first monomer assembly followed by chemical oxidation to achieve polymerization. We show that Aplysia neurons grown on 2D-PAN exhibit an unusual growth pattern and adhesion to this conducting substrate that is manifested by the formation of giant lamellipodia. The lamellipodial domains are characterized by small gap between the plasma membrane and the 2D-PAN substrate (ca. 30 nm) and actin rich skeleton resembling the skeleton of growth cones. This behavior is characteristic to uniform substrates containing only 2D-PAN. However, in patterned substrates containing additionally poly(L-lysine) Aplysia neurons prefer to extend new neurites on the poly(L-lysine) domains.
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Affiliation(s)
- R Oren
- Department of Neurobiology, the Hebrew University of Jerusalem, Jerusalem 91904, Israel
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36
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Wang JT, Medress ZA, Barres BA. Axon degeneration: molecular mechanisms of a self-destruction pathway. ACTA ACUST UNITED AC 2012; 196:7-18. [PMID: 22232700 PMCID: PMC3255986 DOI: 10.1083/jcb.201108111] [Citation(s) in RCA: 308] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Axon degeneration is a characteristic event in many neurodegenerative conditions including stroke, glaucoma, and motor neuropathies. However, the molecular pathways that regulate this process remain unclear. Axon loss in chronic neurodegenerative diseases share many morphological features with those in acute injuries, and expression of the Wallerian degeneration slow (WldS) transgene delays nerve degeneration in both events, indicating a common mechanism of axonal self-destruction in traumatic injuries and degenerative diseases. A proposed model of axon degeneration is that nerve insults lead to impaired delivery or expression of a local axonal survival factor, which results in increased intra-axonal calcium levels and calcium-dependent cytoskeletal breakdown.
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Affiliation(s)
- Jack T Wang
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Assembly of a new growth cone after axotomy: the precursor to axon regeneration. Nat Rev Neurosci 2012; 13:183-93. [PMID: 22334213 DOI: 10.1038/nrn3176] [Citation(s) in RCA: 321] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The assembly of a new growth cone is a prerequisite for axon regeneration after injury. Creation of a new growth cone involves multiple processes, including calcium signalling, restructuring of the cytoskeleton, transport of materials, local translation of messenger RNAs and the insertion of new membrane and cell surface molecules. In axons that have an intrinsic ability to regenerate, these processes are executed in a timely fashion. However, in axons that lack regenerative capacity, such as those of the mammalian CNS, several of the steps that are required for regeneration fail, and these axons do not begin the growth process. Identification of the points of failure can suggest targets for promoting regeneration.
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Ghaffarieh A, Levin LA. Optic nerve disease and axon pathophysiology. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2012. [PMID: 23206593 DOI: 10.1016/b978-0-12-398309-1.00002-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Optic neuropathy is the most common cause of irreversible blindness worldwide. Although the most common optic neuropathy is glaucoma, there are also many other optic neuropathies, for example, those associated with multiple sclerosis, giant cell arteritis, ischemia, and many other diseases. In almost all cases, the pathogenesis involves injury to the retinal ganglion cell axon, with consequent somal and axonal degeneration. This chapter reviews the clinical and pathophysiological properties associated with three of the most common optic neuropathies, as well as recent findings in understanding axonal degeneration. It concludes with a status report on therapies for optic nerve disease, including axoprotection, an approach being studied that has the goal of maintaining axonal integrity and function after injury.
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Affiliation(s)
- Alireza Ghaffarieh
- Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
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39
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Schevzov G, Curthoys NM, Gunning PW, Fath T. Functional diversity of actin cytoskeleton in neurons and its regulation by tropomyosin. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 298:33-94. [PMID: 22878104 DOI: 10.1016/b978-0-12-394309-5.00002-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Neurons comprise functionally, molecularly, and spatially distinct subcellular compartments which include the soma, dendrites, axon, branches, dendritic spines, and growth cones. In this chapter, we detail the remarkable ability of the neuronal cytoskeleton to exquisitely regulate all these cytoplasmic distinct partitions, with particular emphasis on the microfilament system and its plethora of associated proteins. Importance will be given to the family of actin-associated proteins, tropomyosin, in defining distinct actin filament populations. The ability of tropomyosin isoforms to regulate the access of actin-binding proteins to the filaments is believed to define the structural diversity and dynamics of actin filaments and ultimately be responsible for the functional outcome of these filaments.
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Affiliation(s)
- Galina Schevzov
- Oncology Research Unit, Department of Pharmacology, School of Medical Sciences, University of New South Wales, Kensington, Australia
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Fendyur A, Mazurski N, Shappir J, Spira ME. Formation of Essential Ultrastructural Interface between Cultured Hippocampal Cells and Gold Mushroom-Shaped MEA- Toward "IN-CELL" Recordings from Vertebrate Neurons. FRONTIERS IN NEUROENGINEERING 2011; 4:14. [PMID: 22163219 PMCID: PMC3233721 DOI: 10.3389/fneng.2011.00014] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Accepted: 11/17/2011] [Indexed: 11/17/2022]
Abstract
Using cultured Aplysia neurons we recently reported on the development of a novel approach in which an extracellular, non-invasive multi-electrode-array system provides multisite, attenuated, intracellular recordings of subthreshold synaptic potentials, and action potentials (APs), the so called “IN-CELL” recording configuration (to differentiate it from intracellular recordings). Because of its non-invasive nature, the configuration can be used for long term semi intracellular electrophysiological monitoring of APs and synaptic potentials. Three principals converge to generate the IN-CELL configuration: (a) engulfment of approximately 1 μm size gold mushroom-shaped microelectrodes (gMμE) by the neurons, (b) formation of high seal resistance between the cell’s plasma membrane and the engulfed gMμE, and (c), autonomous localized increased conductance of the membrane patch facing the gMμE. Using dissociated rat hippocampal cultures we report here that the necessary morphological and ultrastructural relationships to generate the IN-CELL recording configuration are formed between hippocampal cells and the gMμEs. Interestingly, even <1 μm thin branches expand and engulf the gMμE structures. Recordings of spontaneous electrical activity revealed fast ∼2 ms, 0.04–0.75 mV positive monophasic APs (FPMP). We propose that the FPMP are attenuated APs generated by neurons that engulf gMμEs. Computer simulations of analog electrical circuits depicting the cell–gMμE configuration point out the parameters that should be altered to improve the neuron–gMμE electrical coupling.
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Affiliation(s)
- Anna Fendyur
- Department of Neurobiology, The Life Sciences Institute, The Hebrew University of Jerusalem Jerusalem, Israel
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41
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Rescue of neurons from undergoing hallmark tau-induced Alzheimer's disease cell pathologies by the antimitotic drug paclitaxel. Neurobiol Dis 2011; 43:163-75. [DOI: 10.1016/j.nbd.2011.03.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Revised: 02/14/2011] [Accepted: 03/06/2011] [Indexed: 11/18/2022] Open
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Bloom OE, Morgan JR. Membrane trafficking events underlying axon repair, growth, and regeneration. Mol Cell Neurosci 2011; 48:339-48. [PMID: 21539917 DOI: 10.1016/j.mcn.2011.04.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 04/11/2011] [Accepted: 04/14/2011] [Indexed: 12/31/2022] Open
Abstract
Two central challenges for the field of neurobiology are to understand how axons grow and make proper synaptic connections under normal conditions and how they repair their membranes and mount regenerative responses after injury. At the most reductionist level, the first step toward addressing these challenges is to delineate the cellular and molecular processes by which an axon extends from its cell body. Underlying axon extension are questions of appropriate timing and mechanisms that establish or maintain the axon's polarity, initiate growth cone formation, and promote axon outgrowth and synapse formation. After injury, the problem is even more complicated because the neuron must also repair its damaged membrane, redistribute or manufacture what it needs in order to survive, and grow and form new synapses within a more mature, complex environment. While other reviews have focused extensively on the signaling events and cytoskeletal rearrangements that support axon outgrowth and regeneration, we focus this review instead on the underlying membrane trafficking events underlying these processes. Though the mechanisms are still under active investigation, the key roles played by membrane trafficking events during axon repair, growth, and regeneration have been elucidated through elegant comparative studies in both invertebrate and vertebrate organisms. Taken together, a model emerges indicating that the critical requirements for ensuring proper membrane sealing and axon extension include iterative bouts of SNARE mediated exocytosis, endocytosis, and functional links between vesicles and the actin cytoskeleton, similar to the mechanisms utilized during synaptic transmission. This article is part of a Special Issue entitled 'Neuronal Function'.
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Affiliation(s)
- Ona E Bloom
- The Center for Autoimmune and Musculoskeletal Disease, The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, NY 11030, USA
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43
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Skouras E, Ozsoy U, Sarikcioglu L, Angelov DN. Intrinsic and therapeutic factors determining the recovery of motor function after peripheral nerve transection. Ann Anat 2011; 193:286-303. [PMID: 21458252 DOI: 10.1016/j.aanat.2011.02.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Revised: 02/03/2011] [Accepted: 02/04/2011] [Indexed: 01/01/2023]
Abstract
Insufficient recovery after peripheral nerve injury has been attributed to (i) poor pathfinding of regrowing axons, (ii) excessive collateral axonal branching at the lesion site and (iii) polyneuronal innervation of the neuromuscular junctions (NMJ). The facial nerve transection model has been used initially to measure restoration of function after varying therapies and to examine the mechanisms underlying their effects. Since it is very difficult to control the navigation of several thousand axons, efforts concentrated on collateral branching and NMJ-polyinnervation. Treatment with antibodies against trophic factors to combat branching improved the precision of reinnervation, but had no positive effects on functional recovery. This suggested that polyneuronal reinnervation--rather than collateral branching--may be the critical limiting factor. The former could be reduced by pharmacological agents known to perturb microtubule assembly and was followed by recovery of function. Because muscle polyinnervation is activity-dependent and can be manipulated, attempts to design a clinically feasible therapy were performed by electrical stimulation or by soft tissue massage. Electrical stimulation applied to the transected facial nerve or to paralysed facial muscles did not improve vibrissal motor performance and failed to diminish polyinnervation. In contrast, gentle stroking of the paralysed muscles (vibrissal, orbicularis oculi, tongue musculature) resulted in full recovery of function. This manual stimulation was also effective after hypoglossal-facial nerve suture and after interpositional nerve grafting, but not after surgical reconstruction of the median nerve. All these findings raise hopes that clinically feasible and effective therapies could be soon designed and tested.
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Affiliation(s)
- Emmanouil Skouras
- Department of Orthopedics and Traumatology, University of Cologne, Joseph-Stelzmann-Strasse 9, Cologne, Germany
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44
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Angelov DN. Factors Limiting Motor Recovery After Facial Nerve Injury. PHYSICAL REHABILITATION OF PARALYSED FACIAL MUSCLES: FUNCTIONAL AND MORPHOLOGICAL CORRELATES 2011. [DOI: 10.1007/978-3-642-18120-7_1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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45
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Kao PF, Davis DA, Banigan MG, Vanderburg CR, Seshadri S, Delalle I. Modulators of cytoskeletal reorganization in CA1 hippocampal neurons show increased expression in patients at mid-stage Alzheimer's disease. PLoS One 2010; 5:e13337. [PMID: 20967212 PMCID: PMC2954170 DOI: 10.1371/journal.pone.0013337] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Accepted: 09/15/2010] [Indexed: 01/19/2023] Open
Abstract
During the progression of Alzheimer's disease (AD), hippocampal neurons undergo cytoskeletal reorganization, resulting in degenerative as well as regenerative changes. As neurofibrillary tangles form and dystrophic neurites appear, sprouting neuronal processes with growth cones emerge. Actin and tubulin are indispensable for normal neurite development and regenerative responses to injury and neurodegenerative stimuli. We have previously shown that actin capping protein beta2 subunit, Capzb2, binds tubulin and, in the presence of tau, affects microtubule polymerization necessary for neurite outgrowth and normal growth cone morphology. Accordingly, Capzb2 silencing in hippocampal neurons resulted in short, dystrophic neurites, seen in neurodegenerative diseases including AD. Here we demonstrate the statistically significant increase in the Capzb2 expression in the postmortem hippocampi in persons at mid-stage, Braak and Braak stage (BB) III-IV, non-familial AD in comparison to controls. The dynamics of Capzb2 expression in progressive AD stages cannot be attributed to reactive astrocytosis. Moreover, the increased expression of Capzb2 mRNA in CA1 pyramidal neurons in AD BB III-IV is accompanied by an increased mRNA expression of brain derived neurotrophic factor (BDNF) receptor tyrosine kinase B (TrkB), mediator of synaptic plasticity in hippocampal neurons. Thus, the up-regulation of Capzb2 and TrkB may reflect cytoskeletal reorganization and/or regenerative response occurring in hippocampal CA1 neurons at a specific stage of AD progression.
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Affiliation(s)
- Patricia F. Kao
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - David A. Davis
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Meredith G. Banigan
- Advanced Tissue Research Center, Harvard NeuroDiscovery Center, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Charles R. Vanderburg
- Advanced Tissue Research Center, Harvard NeuroDiscovery Center, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Sudha Seshadri
- Department of Neurology, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Ivana Delalle
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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46
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Shemesh OA, Spira ME. Hallmark cellular pathology of Alzheimer's disease induced by mutant human tau expression in cultured Aplysia neurons. Acta Neuropathol 2010; 120:209-22. [PMID: 20422200 DOI: 10.1007/s00401-010-0689-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2010] [Revised: 04/07/2010] [Accepted: 04/11/2010] [Indexed: 11/29/2022]
Abstract
The mechanisms underlying neurodegenerative diseases are the outcome of pathological alterations of evolutionary conserved molecular and cellular cascades. For this reason, Drosophila and C. elegans serve as useful model systems to study various aspects of neurodegenerative diseases. Here, we introduce the advantageous use of cultured Aplysia neurons (which express over 100 disease-related gene homologs shared with mammals), as a platform to study cell biological processes underlying the generation of tauopathy. Using live confocal imaging to follow cytoskeletal elements, autophagosomes, lysosomes, anterogradely and retrogradely transported organelles, complemented with electron microscopy, we demonstrate that the expression of mutant human tau in cultured Aplysia neurons leads to the development of hallmark Alzheimer disease (AD) pathologies. These include a reduction in the number of microtubules and their redistribution, impaired organelle transport, a dramatic accumulation of macro-autophagosomes and lysosomes, compromised neurite morphology and degeneration. Our study demonstrates the accessibility of the platform for long-term live imaging and quantification of subcellular pathological cascades leading to tauopathy. Based on the present study, it is conceivable that this system can also be used to screen for reagents that alter the pathological cascades.
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Affiliation(s)
- Or A Shemesh
- Department of Neurobiology, Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem, Israel
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47
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Clustering of excess growth resources within leading growth cones underlies the recurrent "deposition" of varicosities along developing neurites. Exp Neurol 2010; 225:140-53. [PMID: 20558161 DOI: 10.1016/j.expneurol.2010.06.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2010] [Revised: 05/30/2010] [Accepted: 06/07/2010] [Indexed: 11/21/2022]
Abstract
Varicosities (VRs) are ubiquitous neuronal structures that are considered to serve as presynaptic structures. The mechanisms of their assembly are unknown. Using cultured Aplysia neurons, we found that in the absence of postsynaptic targets, VRs form at the leading edge of extending neurites when anterogradely transported organelles accumulate within the palm of the growth cone (GC) at a rate that exceeds their utilization by the GC machinery. The aggregation of excess organelles at the palm of the GC leads to slowdown of the GC's advance. As the size of the organelle clusters increases, the rate of organelle sequestration diminishes and the supply of building blocks to the GC resumes. The GCs' advance is re-initiated, "leaving behind" an organelle-loaded nascent VR. These mechanisms account for the recurrent "deposition" of almost equally spaced VRs by advancing GCs. Consistent with the view that VRs serve as "ready-to-go" presynaptic terminals, we found that a short train of action potentials leads to exocytosis of labeled vesicles within the varicosities. We propose that the formation and spacing of VRs by advancing GCs is the default outcome of the balance between the rate of supply of growth-supporting resources and the usage of these resources by the GC's machinery at the leading edges of specific neurites.
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Sun F, He Z. Neuronal intrinsic barriers for axon regeneration in the adult CNS. Curr Opin Neurobiol 2010; 20:510-8. [PMID: 20418094 DOI: 10.1016/j.conb.2010.03.013] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Revised: 03/30/2010] [Accepted: 03/31/2010] [Indexed: 10/19/2022]
Abstract
A major reason for the devastating and permanent disabilities after spinal cord and other types of CNS injury is the failure of injured axons to regenerate and to re-build the functional circuits. Thus, a long-standing goal has been to develop strategies that could promote axon regeneration and restore functions. Recent studies revealed that simply removing extracellular inhibitory activities is insufficient for successful axon regeneration in the adult CNS. On the other side, evidence from different species and different models is accumulating to support the notion that diminished intrinsic regenerative ability of mature neurons is a major contributor to regeneration failure. This review will summarize the molecular mechanisms regulating intrinsic axon growth capacity in the adult CNS and discuss potential implications for therapeutic strategies.
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Affiliation(s)
- Fang Sun
- F.M. Kirby Neurobiology Center, Children's Hospital, and Department of Neurology, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA
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49
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Vanderburg CR, Davis DA, Diamond RE, Kao PF, Delalle I. Capzb2 PROTEIN EXPRESSION IN THE BRAINS OF PATIENTS DIAGNOSED WITH ALZHEIMER'S DISEASE AND HUNTINGTON'S DISEASE. Transl Neurosci 2010; 1:55-58. [PMID: 29662700 PMCID: PMC5899514 DOI: 10.2478/v10134-010-0008-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The silencing of actin capping protein β2, Capzb2, by RNAi in developing cultured neurons results in short, dystrophic neurites reminiscent of cytoskeletal changes seen in diverse neurodegenerative diseases, including Alzheimer's disease (AD) and Huntington's disease (HD). Actin and tubulin are two major cytoskeletal proteins indispensable for normal neurite development and regenerative responses to injury and neurodegenerative stimuli. We have previously shown that Capzb2 binds tubulin and, in the presence of microtubule- associated protein tau, affects microtubule polymerization necessary for neurite outgrowth and normal growth cone morphology. Accordingly, Capzb2 silencing in hippocampal neurons results in short neurites with abnormal growth cones. Decreased neurite length is found in both AD and HD. In the first step towards uncovering the possible role of Capzb2 in these diseases, we studied Capzb2 protein expression in the postmortem brains of AD and HD patients. To determine whether disease-specific changes in Capzb2 protein accompany the progression of neurodegeneration, we performed Western Blot analysis of prefrontal cortices (PFC) and hippocampi (HPC) in AD patients and of PFC and heads of caudate nuclei (HCN) in HD patients. Our results show disease- and area-specific dynamics in the levels of Capzb2 protein expression in the progressive stages of AD and HD.
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Affiliation(s)
- Charles R. Vanderburg
- Advanced Tissue Research Center, Harvard NeuroDiscovery Center, Massachusetts General Hospital, Building 114, 16 St, Charlestown, MA 02129
| | - David A. Davis
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, 715 Albany Street, Boston, MA 02118
| | - Rachel E. Diamond
- Advanced Tissue Research Center, Harvard NeuroDiscovery Center, Massachusetts General Hospital, Building 114, 16 St, Charlestown, MA 02129
| | - Patricia F. Kao
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, 715 Albany Street, Boston, MA 02118
| | - Ivana Delalle
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, 715 Albany Street, Boston, MA 02118
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50
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Extrinsic and intrinsic factors controlling axonal regeneration after spinal cord injury. Expert Rev Mol Med 2009; 11:e37. [PMID: 19968910 DOI: 10.1017/s1462399409001288] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Spinal cord injury is one of the most devastating conditions that affects the central nervous system. It can lead to permanent disability and there are around two million people affected worldwide. After injury, accumulation of myelin debris and formation of an inhibitory glial scar at the site of injury leads to a physical and chemical barrier that blocks axonal growth and regeneration. The mammalian central nervous system thus has a limited intrinsic ability to repair itself after injury. To improve axonal outgrowth and promote functional recovery, it is essential to identify the various intrinsic and extrinsic factors controlling regeneration and navigation of axons within the inhibitory environment of the central nervous system. Recent advances in spinal cord research have opened new avenues for the exploration of potential targets for repairing the cord and improving functional recovery after trauma. Here, we discuss some of the important key molecules that could be harnessed for repairing spinal cord injury.
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