scholarly journals Myelinophagy: Schwann cells dine in

2015 ◽  
Vol 210 (1) ◽  
pp. 9-10 ◽  
Author(s):  
Michael Thumm ◽  
Mikael Simons
Keyword(s):  
Schwann Cells ◽  
Nerve Injury ◽  
Injury Site ◽  
Selective Autophagy ◽  
Cell Biol

When nerve injury occurs, the axon and myelin fragments distal to the injury site have to be cleared away before repair. In this issue, Gomez-Sanchez et al. (2015; J. Cell Biol. http://dx.doi.org/10.1083/jcb.201503019) find that clearance of the damaged myelin within Schwann cells occurs not by phagocytosis but rather via selective autophagy, in a process they term “myelinophagy.”

scholarly journals Schwann cell autophagy, myelinophagy, initiates myelin clearance from injured nerves

2015 ◽  
Vol 210 (1) ◽  
pp. 153-168 ◽  
Author(s):  
Jose A. Gomez-Sanchez ◽  
Lucy Carty ◽  
Marta Iruarrizaga-Lejarreta ◽  
Marta Palomo-Irigoyen ◽  
Marta Varela-Rey ◽  
...  
Keyword(s):  
Schwann Cell ◽  
Schwann Cells ◽  
Nerve Injury ◽  
Peripheral Nerves ◽  
Wallerian Degeneration ◽  
Molecular Mechanisms ◽  
Demyelinating Disease ◽  
Cell Reprogramming ◽  
Selective Autophagy ◽  
Wide Range

Although Schwann cell myelin breakdown is the universal outcome of a remarkably wide range of conditions that cause disease or injury to peripheral nerves, the cellular and molecular mechanisms that make Schwann cell–mediated myelin digestion possible have not been established. We report that Schwann cells degrade myelin after injury by a novel form of selective autophagy, myelinophagy. Autophagy was up-regulated by myelinating Schwann cells after nerve injury, myelin debris was present in autophagosomes, and pharmacological and genetic inhibition of autophagy impaired myelin clearance. Myelinophagy was positively regulated by the Schwann cell JNK/c-Jun pathway, a central regulator of the Schwann cell reprogramming induced by nerve injury. We also present evidence that myelinophagy is defective in the injured central nervous system. These results reveal an important role for inductive autophagy during Wallerian degeneration, and point to potential mechanistic targets for accelerating myelin clearance and improving demyelinating disease.

Transplantation of Schwann cells in a collagen tube for the repair of large, segmental peripheral nerve defects in rats

2013 ◽  
Vol 119 (3) ◽  
pp. 720-732 ◽  
Author(s):  
Yerko A. Berrocal ◽  
Vania W. Almeida ◽  
Ranjan Gupta ◽  
Allan D. Levi
Keyword(s):  
Sciatic Nerve ◽  
Peripheral Nerve ◽  
Schwann Cells ◽  
Nerve Injury ◽  
Peripheral Nerve Injury ◽  
Fluorescent Protein ◽  
Control Groups ◽  
Myelinated Axons ◽  
Segmental Nerve ◽  
Green Fluorescent

Object Segmental nerve defects pose a daunting clinical challenge, as peripheral nerve injury studies have established that there is a critical nerve gap length for which the distance cannot be successfully bridged with current techniques. Construction of a neural prosthesis filled with Schwann cells (SCs) could provide an alternative treatment to successfully repair these long segmental gaps in the peripheral nervous system. The object of this study was to evaluate the ability of autologous SCs to increase the length at which segmental nerve defects can be bridged using a collagen tube. Methods The authors studied the use of absorbable collagen conduits in combination with autologous SCs (200,000 cells/μl) to promote axonal growth across a critical size defect (13 mm) in the sciatic nerve of male Fischer rats. Control groups were treated with serum only–filled conduits of reversed sciatic nerve autografts. Animals were assessed for survival of the transplanted SCs as well as the quantity of myelinated axons in the proximal, middle, and distal portions of the channel. Results Schwann cell survival was confirmed at 4 and 16 weeks postsurgery by the presence of prelabeled green fluorescent protein–positive SCs within the regenerated cable. The addition of SCs to the nerve guide significantly enhanced the regeneration of myelinated axons from the nerve stump into the proximal (p < 0.001) and middle points (p < 0.01) of the tube at 4 weeks. The regeneration of myelinated axons at 16 weeks was significantly enhanced throughout the entire length of the nerve guide (p < 0.001) as compared with their number in a serum–only filled tube and was similar in number compared with the reversed autograft. Autotomy scores were significantly lower in the animals whose sciatic nerve was repaired with a collagen conduit either without (p < 0.01) or with SCs (p < 0.001) when compared with a reversed autograft. Conclusions The technique of adding SCs to a guidance channel significantly enhanced the gap distance that can be repaired after peripheral nerve injury with long segmental defects and holds promise in humans. Most importantly, this study represents some of the first essential steps in bringing autologous SC-based therapies to the domain of peripheral nerve injuries with long segmental defects.

Axon Regeneration in Peripheral Nerves

2021 ◽  
Author(s):  
Arthur English
Keyword(s):  
Nerve Injury ◽  
Peripheral Nerves ◽  
Axon Regeneration ◽  
Axon Growth ◽  
Injury Site ◽  
Genetic Manipulations ◽  
Novel Treatments ◽  
The Central Nervous System ◽  
Experimental Treatments ◽  
Axonal Protein

Despite the intrinsically greater capacity for axons to regenerate in injured peripheral nerves than after injury to the central nervous system, functional recovery after most nerve injuries is very poor. A need for novel treatments that will enhance axon regeneration and improve recovery is substantial. Several such experimental treatments have been studied, each based on part of the stereotypical cellular responses that follow a nerve injury. Genetic manipulations of Schwann cells that have transformed from a myelinating to a repair phenotype that either increase their production of axon growth-promoting molecules, decrease production of inhibitors, or both result in enhanced regeneration. Local or systemic application of these molecules or small molecule mimetics of them also will promote regeneration. The success of treatments that stimulate axonal protein synthesis at the site of the nerve injury and in the growing axons, an early and important response to axon injury, is significant, as is that of manipulations of the types of immune cells that migrate into the injury site or peripheral ganglia. Modifications of the extracellular matrix through which the regenerating axons course, including the stimulation of new blood vessel formation, promotes the navigation of nascent regenerating neurites past the injury site, resulting in greater axon regeneration. Experimental induction of expression of regeneration associated gene activity in the cell bodies of the injured neurons is especially useful when regenerating axons must regenerate over long distances to reinnervate targets. The consistently most effective experimental approach to improving axon regeneration in peripheral nerves has been to increase the activity of the injured neurons, either through electrical, optical, or chemogenetic stimulation or through exercise. These activity-dependent experimental therapies show greatest promise for translation to use in patients.

scholarly journals S100ß and fibroblast growth factor-2 are present in cultured Schwann cells and may exert paracrine actions on the peripheral nerve injury

2008 ◽  
Vol 23 (6) ◽  
pp. 555-560 ◽  
Author(s):  
Tatiana Duobles ◽  
Thais de Sousa Lima ◽  
Beatriz de Freitas Azevedo Levy ◽  
Gerson Chadi
Keyword(s):  
Growth Factor ◽  
Sciatic Nerve ◽  
Fibroblast Growth Factor ◽  
Schwann Cells ◽  
Nerve Injury ◽  
Satellite Cells ◽  
Peripheral Nerves ◽  
Fibroblast Growth Factor 2 ◽  
Fibroblast Growth ◽  
Cultured Schwann Cells

PURPOSE: The neurotrophic factor fibroblast growth factor-2 (FGF-2, bFGF) and Ca++ binding protein S100ß are expressed by the Schwann cells of the peripheral nerves and by the satellite cells of the dorsal root ganglia (DRG). Recent studies have pointed out the importance of the molecules in the paracrine mechanisms related to neuronal maintenance and plasticity of lesioned motor and sensory peripheral neurons. Moreover, cultured Schwann cells have been employed experimentally in the treatment of central nervous system lesions, in special the spinal cord injury, a procedure that triggers an enhanced sensorymotor function. Those cells have been proposed to repair long gap nerve injury. METHODS: Here we used double labeling immunohistochemistry and Western blot to better characterize in vitro and in vivo the presence of the proteins in the Schwann cells and in the satellite cells of the DRG as well as their regulation in those cells after a crush of the rat sciatic nerve. RESULTS: FGF-2 and S100ß are present in the Schwann cells of the sciatic nerve and in the satellite cells of the DRG. S100ß positive satellite cells showed increased size of the axotomized DRG and possessed elevated amount of FGF-2 immunoreactivity. Reactive satellite cells with increased FGF-2 labeling formed a ring-like structure surrounding DRG neuronal cell bodies.Reactive S100ß positive Schwann cells of proximal stump of axotomized sciatic nerve also expressed higher amounts of FGF-2. CONCLUSION: Reactive peripheral glial cells synthesizing FGF-2 and S100ß may be important in wound repair and restorative events in the lesioned peripheral nerves.

scholarly journals Terminal Schwann Cells Participate in Neuromuscular Synapse Remodeling during Reinnervation following Nerve Injury

2014 ◽  
Vol 34 (18) ◽  
pp. 6323-6333 ◽  
Author(s):  
H. Kang ◽  
L. Tian ◽  
M. Mikesh ◽  
J. W. Lichtman ◽  
W. J. Thompson
Keyword(s):  
Schwann Cells ◽  
Nerve Injury ◽  
Neuromuscular Synapse ◽  
Terminal Schwann Cells

Gene transfer to schwann cells after peripheral nerve injury: A delivery system for therapeutic agents

1998 ◽  
Vol 43 (2) ◽  
pp. 205-211 ◽  
Author(s):  
Jesper Sørensen ◽  
Georg Haase ◽  
Christian Krarup ◽  
Helene Gilgenkrantz ◽  
Axel Kahn ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Peripheral Nerve ◽  
Schwann Cells ◽  
Nerve Injury ◽  
Delivery System ◽  
Peripheral Nerve Injury ◽  
Therapeutic Agents

scholarly journals The dynamic changes of main cell types in the microenvironment of sciatic nerves following sciatic nerve injury and the influence of let-7 on their distribution

RSC Advances ◽  
2018 ◽  
Vol 8 (72) ◽  
pp. 41181-41191 ◽  
Author(s):  
Tianmei Qian ◽  
Pan Wang ◽  
Qianqian Chen ◽  
Sheng Yi ◽  
Qianyan Liu ◽  
...  
Keyword(s):  
Sciatic Nerve ◽  
Peripheral Nerve ◽  
Schwann Cells ◽  
Nerve Injury ◽  
Cell Types ◽  
Sciatic Nerve Injury ◽  
Dynamic Changes ◽  
Main Cell ◽  
Sciatic Nerves

Schwann cells (SCs), fibroblasts and macrophages are the main cells in the peripheral nerve stumps.

scholarly journals Suppressing Sema3A expression in muscle satellite cells affects terminal Schwann cells after muscle and nerve injury

2021 ◽  
Vol 35 (S1) ◽  
Author(s):  
Nasibeh Daneshvar ◽  
Ryuichi Tatsumi ◽  
Yuji Matsuyoshi ◽  
Judy Anderson
Keyword(s):  
Schwann Cells ◽  
Nerve Injury ◽  
Satellite Cells ◽  
Muscle Satellite Cells ◽  
Terminal Schwann Cells
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