04 and A007-sulfatide antibodies bind to embryonic Schwann cells prior to the appearance of galactocerebroside; regulation of the antigen by axon-Schwann cell signals and cyclic AMP

Development ◽  
1990 ◽  
Vol 109 (1) ◽  
pp. 105-116 ◽  
Author(s):  
R. Mirsky ◽  
C. Dubois ◽  
L. Morgan ◽  
K.R. Jessen

In the rat sciatic nerve, the relationship between Schwann cells, axons, the extracellular matrix and perineurial sheath cells undergoes extensive modification between embryo day 15 and the onset of myelination during the first postnatal day. Little is known about molecular changes in Schwann cells in this important prenatal period. In the present paper, we use immunofluorescence to study the prenatal development and postnatal regulation of the antigen(s) recognized by the 04 monoclonal antibody and a well-characterized rat monoclonal antibody to sulfatide, A007. We show that, in a series of immunochemical tests, the 04 antibody recognizes only sulfatide in neonatal and adult rat nerves. Both antibodies first bind to Schwann cells in the sciatic nerve at embryo day 16–17, and all Schwann cells bind both antibodies at birth. In the adult nerve, both nonmyelin-forming and myelin-forming cells are labelled with the antibodies. Schwann cells dissociated from embryo day 15 nerves and cultured in the absence of axons develop neither 04 nor A007 binding on schedule, and 04-positive and A007-positive Schwann cells from postnatal nerves lose the ability to bind these antibodies during the first few days in culture. Schwann cells in the distal stump of transected nerves also sharply down-regulate cell surface binding of 04. High numbers of 04-positive or A007-positive Schwann cells reappear in cultures treated with agents that mimic or elevate intracellular cAMP. We conclude that two anti-sulfatide antibodies 04 and A007, recognize an antigen, probably sulfatide, that appears very early in Schwann cell development (one to two days prior to galactocerebroside) but is nevertheless subject to upregulation by axonal contact or elevation of intracellular cAMP.

1995 ◽  
Vol 129 (3) ◽  
pp. 789-796 ◽  
Author(s):  
L Cheng ◽  
M Khan ◽  
A W Mudge

Schwann cells in culture divide in response to defined mitogens such as PDGF and glial growth factor (GGF), but proliferation is greatly enhanced if agents such as forskolin, which increases Schwann cell intracellular cAMP, are added at the same time as PDGF or GGF (Davis, J. B., and P. Stroobant. 1990. J. Cell Biol. 110:1353-1360). The effect of forskolin is probably due to an increase in numbers of PDGF receptors (Weinmaster, G., and G. Lemke. 1990. EMBO (Eur. Mol. Biol. Organ.) J. 9:915-920. Neuropeptides and beta-adrenergic agonists have been reported to have no effect on potentiating the mitogenic response of either PDGF or GGF. We show that the neuropeptide calcitonin gene-related peptide (CGRP) increases Schwann cell cAMP levels, but the cells rapidly desensitize. We therefore stimulated the cells in pulsatile fashion to partly overcome the effects of desensitization and show that CGRP can synergize with PDGF to stimulate Schwann cell proliferation, and that CGRP is as effective as forskolin in the pulsatile regime. CGRP is a good substrate for the neutral endopeptidase 24.11. Schwann cells in vivo have this protease on their surface, so the action of CGRP could be terminated by this enzyme and desensitization prevented. We therefore suggest that CGRP may play an important role in stimulating Schwann cell proliferation by regulating the response of mitogenic factors such as PDGF.


2021 ◽  
Vol 14 ◽  
Author(s):  
Bo Jia ◽  
Wei Huang ◽  
Yu Wang ◽  
Peng Zhang ◽  
Zhiwei Wang ◽  
...  

While Nogo protein demonstrably inhibits nerve regeneration in the central nervous system (CNS), its effect on Schwann cells in peripheral nerve repair and regeneration following sciatic nerve injury remains unknown. In this research, We assessed the post-injury expression of Nogo-C in an experimental mouse model of sciatic nerve-crush injury. Nogo-C knockout (Nogo-C–/–) mouse was generated to observe the effect of Nogo-C on sciatic nerve regeneration, Schwann cell apoptosis, and myelin disintegration after nerve injury, and the effects of Nogo-C on apoptosis and dedifferentiation of Schwann cells were observed in vitro. We found that the expression of Nogo-C protein at the distal end of the injured sciatic nerve increased in wild type (WT) mice. Compared with the injured WT mice, the proportion of neuronal apoptosis was significantly diminished and the myelin clearance rate was significantly elevated in injured Nogo-C–/– mice; the number of nerve fibers regenerated and the degree of myelination were significantly elevated in Nogo-C–/– mice on Day 14 after injury. In addition, the recovery of motor function was significantly accelerated in the injured Nogo-C–/– mice. The overexpression of Nogo-C in primary Schwann cells using adenovirus-mediated gene transfer promoted Schwann cells apoptosis. Nogo-C significantly reduced the ratio of c-Jun/krox-20 expression, indicating its inhibition of Schwann cell dedifferentiation. Above all, we hold the view that the expression of Nogo-C increases following peripheral nerve injury to promote Schwann cell apoptosis and inhibit Schwann cell dedifferentiation, thereby inhibiting peripheral nerve regeneration.


Development ◽  
1989 ◽  
Vol 105 (2) ◽  
pp. 251-262 ◽  
Author(s):  
L.C. Smith-Thomas ◽  
J.W. Fawcett

During embryonic development, neural crest cells differentiate into a wide variety of cell types including Schwann cells of the peripheral nervous system. In order to establish when neural crest cells first start to express a Schwann cell phenotype immunocytochemical techniques were used to examine rat premigratory neural crest cell cultures for the presence of Schwann cell markers. Cultures were fixed for immunocytochemistry after culture periods ranging from 1 to 24 days. Neural crest cells were identified by their morphology and any neural tube cells remaining in the cultures were identified by their epithelial morphology and immunocytochemically. As early as 1 to 2 days in culture, approximately one third of the neural crest cells stained with m217c, a monoclonal antibody that appears to recognize the same antigen as rat neural antigen-1 (RAN-1). A similar proportion of cells were immunoreactive in cultures stained with 192-IgG, a monoclonal antibody that recognizes the rat nerve growth factor receptor. The number of immunoreactive cells increased with time in culture. After 16 days in culture, nests of cells, many of which had a bipolar morphology, were present in the area previously occupied by neural crest cells. The cells in the nests were often associated with neurons and were immunoreactive for m217c, 192-IgG and antibody to S-100 protein and laminin, indicating that the cells were Schwann cells. At all culture periods examined, neural crest cells did not express glial fibrillary acidic protein. These results demonstrate that cultured premigratory neural crest cells express early Schwann cell markers and that some of these cells differentiate into Schwann cells. These observations suggest that some neural crest cells in vivo may be committed to forming Schwann cells and will do so provided that they then proceed to encounter the correct environmental cues during embryonic development.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ella Ittner ◽  
Anna C. Hartwig ◽  
Olga Elsesser ◽  
Hannah M. Wüst ◽  
Franziska Fröb ◽  
...  

AbstractThe three SoxD proteins, Sox5, Sox6 and Sox13, represent closely related transcription factors with important roles during development. In the developing nervous system, SoxD proteins have so far been primarily studied in oligodendroglial cells and in interneurons of brain and spinal cord. In oligodendroglial cells, Sox5 and Sox6 jointly maintain the precursor state, interfere with terminal differentiation, and thereby ensure the proper timing of myelination in the central nervous system. Here we studied the role of SoxD proteins in Schwann cells, the functional counterpart of oligodendrocytes in the peripheral nervous system. We show that Schwann cells express Sox5 and Sox13 but not Sox6. Expression was transient and ceased with the onset of terminal differentiation. In mice with early Schwann cell-specific deletion of both Sox5 and Sox13, embryonic Schwann cell development was not substantially affected and progressed normally into the promyelinating stage. However, there was a mild and transient delay in the myelination of the peripheral nervous system of these mice. We therefore conclude that SoxD proteins—in stark contrast to their action in oligodendrocytes—promote differentiation and myelination in Schwann cells.


2005 ◽  
Vol 25 (5) ◽  
pp. 1821-1829 ◽  
Author(s):  
Ralf P. Friedrich ◽  
Beate Schlierf ◽  
Ernst R. Tamm ◽  
Michael R. Bösl ◽  
Michael Wegner

ABSTRACT For differentiation, Schwann cells rely on the class III POU domain transcription factor Oct-6, which is expressed transiently when Schwann cells have established a one-to-one relation with axons but have not yet started to myelinate. Loss of Oct-6 leads to a transient arrest in this promyelinating stage and a delay in myelination. Although the closely related POU domain protein Brn-2 is coexpressed with Oct-6 in Schwann cells, its loss has only mild consequences. Combined loss of both POU domain proteins, in contrast, dramatically increases the myelination delay, raising the question of how related POU domain proteins compare to each other in their activities. Here, we have replaced Oct-6 expression in the mouse with expression of the class III POU domain protein Brn-1. Although this protein is not normally expressed in Schwann cells, Brn-1 was capable of fully replacing Oct-6. Brn-1 efficiently induced Krox-20 expression as a prerequisite for myelination. Onset and extent of myelination were also indistinguishable from that of the wild type in mice that carried only Brn-1 instead of Oct-6 alleles. Similar to Oct-6, Brn-1 down-regulated its own expression at later stages of myelination. Thus, class III POU domain proteins can fully replace each other in Schwann cell development.


2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Fabian Szepanowski ◽  
Maximilian Winkelhausen ◽  
Rebecca D. Steubing ◽  
Anne K. Mausberg ◽  
Christoph Kleinschnitz ◽  
...  

Abstract Background Lysophosphatidic acid (LPA) is a pleiotropic lipid messenger that addresses at least six specific G-protein coupled receptors. Accumulating evidence indicates a significant involvement of LPA in immune cell regulation as well as Schwann cell physiology, with potential relevance for the pathophysiology of peripheral neuroinflammation. However, the role of LPA signaling in inflammatory neuropathies has remained completely undefined. Given the broad expression of LPA receptors on both Schwann cells and cells of the innate and adaptive immune system, we hypothesized that inhibition of LPA signaling may ameliorate the course of disease in experimental autoimmune neuritis (EAN). Methods We induced active EAN by inoculation of myelin protein 2 peptide (P255–78) in female Lewis rats. Animals received the orally available LPA receptor antagonist AM095, specifically targeting the LPA1 receptor subtype. AM095 was administered daily via oral gavage in a therapeutic regimen from 10 until 28 days post-immunization (dpi). Analyses were based on clinical testing, hemogram profiles, immunohistochemistry and morphometric assessment of myelination. Results Lewis rats treated with AM095 displayed a significant improvement in clinical scores, most notably during the remission phase. Cellular infiltration of sciatic nerve was only discretely affected by AM095. Hemogram profiles indicated no impact on circulating leukocytes. However, sciatic nerve immunohistochemistry revealed a reduction in the number of Schwann cells expressing the dedifferentiation marker Sox2 paralleled by a corresponding increase in differentiating Sox10-positive Schwann cells. In line with this, morphometric analysis of sciatic nerve semi-thin sections identified a significant increase in large-caliber myelinated axons at 28 dpi. Myelin thickness was unaffected by AM095. Conclusion Thus, LPA1 signaling may present a novel therapeutic target for the treatment of inflammatory neuropathies, potentially affecting regenerative responses in the peripheral nerve by modulating Schwann cell differentiation.


1967 ◽  
Vol 34 (3) ◽  
pp. 735-743 ◽  
Author(s):  
A. K. Asbury

Proliferation of Schwann cells in neonatal mouse sciatic nerve was studied radioautographically in 1-µ glycol methacrylate sections. 28 mice were injected with thymidine-3H, 4 µc/g, 48 hr after birth, and were killed serially over the next 4 days. For the cell cycle following injection, the generation time was approximately 24 hr as determined by grain-count halving data; the duration of synthesis phase was 8 hr as determined from a curve constructed from the per cent of mitotic figures containing label; and the labeling index was 9% at 2 hr after injection. With these estimates, the per cent of Schwann cells proliferating was calculated to be 27%. In addition, roughly 25% of dividing cells appeared to cease division during the cell cycle under study. The relationship of these findings to other events during maturation of nerve is discussed.


2020 ◽  
Author(s):  
Sophie Colombo ◽  
Valérie Petit ◽  
Roselyne Y Wagner ◽  
Delphine Champeval ◽  
Ichiro Yajima ◽  
...  

AbstractThe canonical Wnt/β-catenin pathway governs a multitude of developmental processes in various cell lineages, including the melanocyte lineage. Indeed, β-catenin regulates Mitf-M transcription, the master regulator of this lineage. The first wave of melanocytes to colonize the skin is directly derived from neural crest cells, while a small number of second wave melanocytes is derived from Schwann-cell precursors (SCPs). We investigated the influence of β-catenin in the development of melanocytes of the first and second waves by generating mice expressing a constitutively active form of β-catenin in cells expressing tyrosinase. Constitutive activation of β-catenin did not affect the development of truncal melanoblasts, but led to a marked hyperpigmentation of the paws. By activating β-catenin at various stages of development (E8.5-E11.5), we showed that the activation of β-catenin in bipotent SCPs favored melanoblast specification at the expense of Schwann cells in the limbs within a specific temporal window. In addition, hyperactivation of the Wnt/β-catenin pathway repressed FoxD3 expression, which is necessary for Schwann cell development, through Mitf-M activation. In conclusion, β-catenin overexpression promotes SCP cell-fate decisions towards the melanocyte lineage.Summary statementActivation of β-catenin in bipotent Schwann-cell precursors during a specific developmental window, induces MITF and represses FoxD3 to promote melanoblast cell fate at the expense of Schwann cells in limbs.


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