scholarly journals ErbB2 Signaling in Schwann Cells Is Mostly Dispensable for Maintenance of Myelinated Peripheral Nerves and Proliferation of Adult Schwann Cells after Injury

2006 ◽  
Vol 26 (7) ◽  
pp. 2124-2131 ◽  
Author(s):  
S. Atanasoski
Keyword(s):  
Schwann Cells ◽  
Peripheral Nerves ◽  
Erbb2 Signaling

scholarly journals Laminin γ1 is critical for Schwann cell differentiation, axon myelination, and regeneration in the peripheral nerve

2003 ◽  
Vol 163 (4) ◽  
pp. 889-899 ◽  
Author(s):  
Zu-Lin Chen ◽  
Sidney Strickland
Keyword(s):  
Schwann Cells ◽  
Peripheral Nerves ◽  
Matrix Proteins ◽  
Myelin Proteins ◽  
Sciatic Nerve Crush ◽  
Similar Reduction ◽  
Nerve Crush ◽  
And Function ◽  
Schwann Cell Differentiation

Laminins are heterotrimeric extracellular matrix proteins that regulate cell viability and function. Laminin-2, composed of α2, β1, and γ1 chains, is a major matrix component of the peripheral nervous system (PNS). To investigate the role of laminin in the PNS, we used the Cre–loxP system to disrupt the laminin γ1 gene in Schwann cells. These mice have dramatically reduced expression of laminin γ1 in Schwann cells, which results in a similar reduction in laminin α2 and β1 chains. These mice exhibit motor defects which lead to hind leg paralysis and tremor. During development, Schwann cells that lack laminin γ1 were present in peripheral nerves, and proliferated and underwent apoptosis similar to control mice. However, they were unable to differentiate and synthesize myelin proteins, and therefore unable to sort and myelinate axons. In mutant mice, after sciatic nerve crush, the axons showed impaired regeneration. These experiments demonstrate that laminin is an essential component for axon myelination and regeneration in the PNS.

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.

A Neuropathy in Goats Caused by Experimental Coyotillo (Karwinskia humboldtiana) Poisoning

1970 ◽  
Vol 7 (5) ◽  
pp. 420-434 ◽  
Author(s):  
K. M. Charlton ◽  
K. R. Pierce
Keyword(s):  
Electron Microscopy ◽  
Sciatic Nerve ◽  
Schwann Cells ◽  
Active Transport ◽  
Peripheral Nerves ◽  
Wallerian Degeneration ◽  
Light And Electron Microscopy ◽  
Segmental Demyelination ◽  
Femoral Site ◽  
Oral Doses

Lesions in peripheral nerves from 12 goats poisoned experimentally with coyotillo were studied by light and electron microscopy. The goats were poisoned with daily oral doses of the ground coyotillo fruits and killed at various times after the first day of dosing. Lesions at a mid-femoral site of the sciatic nerve included swelling of Schwann cells, degeneration of mitochondria, depletion of glycogen, splitting of myelin, segmental demyelination, and Wallerian degeneration. The results were suggestive of primary mitochondrial injury in Schwann cells with resultant impaired active transport, intracellular edema, splitting of myelin, and segmental demyelination.

scholarly journals The macrophage response to central and peripheral nerve injury. A possible role for macrophages in regeneration.

1987 ◽  
Vol 165 (4) ◽  
pp. 1218-1223 ◽  
Author(s):  
V H Perry ◽  
M C Brown ◽  
S Gordon
Keyword(s):  
Optic Nerve ◽  
Peripheral Nerve ◽  
Schwann Cells ◽  
Nerve Injury ◽  
Peripheral Nerves ◽  
Peripheral Nerve Injury ◽  
Macrophage Response ◽  
Large Numbers ◽  
Myelin Degradation ◽  
Degenerating Axons

Using mAbs and immunocytochemistry we have examined the response of macrophages (M phi) after crush injury to the sciatic or optic nerve in the mouse and rat. We have established that large numbers of M phi enter peripheral nerves containing degenerating axons; the M phi are localized to the portion containing damaged axons, and they phagocytose myelin. The period of recruitment of the M phi in the peripheral nerve is before and during the period of maximal proliferation of the Schwann cells. In contrast, the degenerating optic nerve attracts few M phi, and the removal of myelin is much slower. These results show the clearly different responses of M phi to damage in the central and peripheral nervous systems, and suggest that M phi may be an important component of subsequent repair as well as myelin degradation.

scholarly journals ATP Release through Lysosomal Exocytosis from Peripheral Nerves: The Effect of Lysosomal Exocytosis on Peripheral Nerve Degeneration and Regeneration after Nerve Injury

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Junyang Jung ◽  
Hyun Woo Jo ◽  
Hyunseob Kwon ◽  
Na Young Jeong
Keyword(s):  
Peripheral Nerve ◽  
Schwann Cells ◽  
Nerve Injury ◽  
Peripheral Nerves ◽  
Wallerian Degeneration ◽  
Atp Release ◽  
Nerve Degeneration ◽  
Peripheral Neurons ◽  
Charcot Marie Tooth Disease ◽  
Axonal Degradation

Studies have shown that lysosomal activation increases in Schwann cells after nerve injury. Lysosomal activation is thought to promote the engulfment of myelin debris or fragments of injured axons in Schwann cells during Wallerian degeneration. However, a recent interpretation of lysosomal activation proposes a different view of the phenomenon. During Wallerian degeneration, lysosomes become secretory vesicles and are activated for lysosomal exocytosis. The lysosomal exocytosis triggers adenosine 5′-triphosphate (ATP) release from peripheral neurons and Schwann cells during Wallerian degeneration. Exocytosis is involved in demyelination and axonal degradation, which facilitate nerve regeneration following nerve degeneration. At this time, released ATP may affect the communication between cells in peripheral nerves. In this review, our description of the relationship between lysosomal exocytosis and Wallerian degeneration has implications for the understanding of peripheral nerve degenerative diseases and peripheral neuropathies, such as Charcot-Marie-Tooth disease or Guillain-Barré syndrome.

scholarly journals Practical considerations concerning the use of stem cells for peripheral nerve repair

2009 ◽  
Vol 26 (2) ◽  
pp. E2 ◽  
Author(s):  
Sarah Walsh ◽  
_ _ ◽  
Rajiv Midha
Keyword(s):  
Stem Cells ◽  
Peripheral Nerve ◽  
Schwann Cells ◽  
Nerve Injury ◽  
Cell Fate ◽  
Peripheral Nerves ◽  
Nerve Repair ◽  
Precursor Cells ◽  
Host Cells ◽  
Injured Nerve

In this review the authors intend to demonstrate the need for supplementing conventional repair of the injured nerve with alternative therapies, namely transplantation of stem or progenitor cells. Although peripheral nerves do exhibit the potential to regenerate axons and reinnervate the end organ, outcome following severe nerve injury, even after repair, remains relatively poor. This is likely because of the extensive injury zone that prevents axon outgrowth. Even if outgrowth does occur, a relatively slow growth rate of regeneration results in prolonged denervation of the distal nerve. Whereas denervated Schwann cells (SCs) are key players in the early regenerative success of peripheral nerves, protracted loss of axonal contact renders Schwann cells unreceptive for axonal regeneration. Given that denervated Schwann cells appear to become effete, one logical approach is to support the distal denervated nerve environment by replacing host cells with those derived exogenously. A number of different sources of stem/precursor cells are being explored for their potential application in the scenario of peripheral nerve injury. The most promising candidate, transplant cells are derived from easily accessible sources such as the skin, bone marrow, or adipose tissue, all of which have demonstrated the capacity to differentiate into Schwann cell–like cells. Although recent studies have shown that stem cells can act as promising and beneficial adjuncts to nerve repair, considerable optimization of these therapies will be required for their potential to be realized in a clinical setting. The authors investigate the relevance of the delivery method (both the number and differentiation state of cells) on experimental outcomes, and seek to clarify whether stem cells must survive and differentiate in the injured nerve to convey a therapeutic effect. As our laboratory uses skin-derived precursor cells (SKPCs) in various nerve injury paradigms, we relate our findings on cell fate to other published studies to demonstrate the need to quantify stem cell survival and differentiation for future studies.

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