scholarly journals Immunocytochemical localization of P0 protein in Golgi complex membranes and myelin of developing rat Schwann cells.

1981 ◽  
Vol 90 (1) ◽  
pp. 1-6 ◽  
Author(s):  
B D Trapp ◽  
Y Itoyama ◽  
N H Sternberger ◽  
R H Quarles ◽  
H Webster
Keyword(s):  
Schwann Cell ◽  
Schwann Cells ◽  
Golgi Complex ◽  
Cell Cytoplasm ◽  
Adult Rats ◽  
Thin Sections ◽  
Myelin Sheaths ◽  
Transmission Electron ◽  
P0 Protein ◽  
Developing Rat

P0 protein, the dominant protein in peripheral nervous system myelin, was studied immunocytochemically in both developing and mature Schwann cells. Trigeminal and sciatic nerves from newborn, 7-d, and adult rats were processed for transmission electron microscopy. Alternating 1-micrometer-thick Epon sections were stained with paraphenylenediamine (PD) or with P0 antiserum according to the peroxidase-antiperoxidase method. To localize P0 in Schwann cell cytoplasm and myelin membranes, the distribution of immunostaining observed in 1-micrometer sections was mapped on electron micrographs of identical areas found in adjacent thin sections. The first P0 staining was observed around axons and/or in cytoplasm of Schwann cells that had established a 1:1 relationship with axons. In newborn nerves, staining of newly formed myelin sheaths was detected more readily with P0 antiserum than with PD. Myelin sheaths with as few as three lamellae could be identified with the light microscope. Very thin sheaths often stained less intensely and part of their circumference frequently was unstained. Schmidt-Lanterman clefts found in more mature sheaths also were unstained. As myelination progressed, intensely stained myelin rings became much more numerous and, in adult nerves, all sheaths were intensely and uniformly stained. Particulate P0 staining also was observed in juxtanuclear areas of Schwann cell cytoplasm. It was most prominent during development, then decreased, but still was detected in adult nerves. The cytoplasmic areas stained by P0 antiserum were rich in Golgi complex membranes.

Remyelination of Demyelinated CNS Axons by Transplanted Human Schwann Cells: The Deleterious Effect of Contaminating Fibroblasts

2001 ◽  
Vol 10 (3) ◽  
pp. 305-315 ◽  
Author(s):  
C. M. H. Brierley ◽  
A. J. Crang ◽  
Y. Iwashita ◽  
J. M. Gilson ◽  
N. J. Scolding ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Schwann Cell ◽  
Schwann Cells ◽  
Axonal Degeneration ◽  
Autologous Transplantation ◽  
Growth Factor Receptor ◽  
Adult Rats ◽  
Demyelinating Lesions ◽  
Cell Implantation

Areas of demyelination can be remyelinated by transplanting myelin-forming cells. Schwann cells are the naturally remyelinating cells of the peripheral nervous system and have a number of features that may make them attractive for cell implantation therapies in multiple sclerosis, in which spontaneous but limited Schwann cell remyelination has been well documented. Schwann cells can be expanded in vitro, potentially affording the opportunity of autologous transplantation; and they might also be spared the demyelinating process in multiple sclerosis. Although rat, cat, and monkey Schwann cells have been transplanted into rodent demyelinating lesions, the behavior of transplanted human Schwann cells has not been evaluated. In this study we examined the consequences of injecting human Schwann cells into areas of acute demyelination in the spinal cords of adult rats. We found that transplants containing significant fibroblast contamination resulted in deposition of large amounts of collagen and extensive axonal degeneration. However, Schwann cell preparations that had been purified by positive immunoselection using antibodies to human low-affinity nerve growth factor receptor containing less than 10% fibroblasts were associated with remyelination. This result indicates that fibroblast contamination of human Schwann cells represents a greater problem than would have been appreciated from previous studies.

Neurofilaments Pack Differently in Different Parts of the Same Axon

1988 ◽  
Vol 46 ◽  
pp. 270-271
Author(s):  
R. L. Price ◽  
R. J. Lasek ◽  
M. J. Katz
Keyword(s):  
Schwann Cell ◽  
Schwann Cells ◽  
Room Temperature ◽  
Oculomotor Nerve ◽  
Cell Cytoplasm ◽  
Myelinated Axons ◽  
Motor Branch ◽  
Dynamic Mechanisms ◽  
Cacodylate Buffer ◽  
Different Parts

Quantifying cytological ultrastructure can reveal subtle but consistent differences in the organization of cytological elements, such as the cytoskeletal polymers. From these differences, it is possible to infer the dynamic mechanisms that contribute to those organizational variations which give cells their regional characteristics (Lasek, 1988). Myelinated axons manifest many regional specializations. Moreover, such axons have a repeating stereotyped pattern of interactions with the numerous Schwann cells that are distributed along their lengths. Within this pattern, certain regional specializations occur repeatedly: nodes of Ranvier, internodal regions with compact simple myelin, and Schmidt-Lanterman (S-L) clefts (i.e., internodal regions where the Schwann cell cytoplasm separates the myelin lamellae). We have quantified neurofilament number and density in these different regions of the axon in order to explore the mechanisms that underlie neuronal shape.Twenty-eight day old chickens were perfused by cardiac puncture with 3-4 1 of fixative (4% paraformaldehyde, 2% glutaraldehyde, 0.005% CaCl2, in 0.1M cacodylate buffer, pH7.4). The somatic motor branch of the oculomotor nerve was removed and fixed overnight at 4°C, followed by a buffer rinse and lh in 1% OsO4 in 0.1M cacodylate at room temperature.

Schwann Cell Reactions in Acute and Chronic Segmental Demyelinating Neuropathies

1968 ◽  
Vol 26 ◽  
pp. 108-109
Author(s):  
Roy O. Weller
Keyword(s):  
Schwann Cell ◽  
Peripheral Nerve ◽  
Schwann Cells ◽  
Myelin Sheath ◽  
Wallerian Degeneration ◽  
Demyelinating Disease ◽  
Segmental Demyelination ◽  
Recovery Stage ◽  
Myelin Sheaths ◽  
Demyelinating Neuropathies

The length of axon that each Schwann cell myelinates in a normal peripheral nerve is approximately proportional to the diameter of the axon and the thickness of the myelin sheath produced. When segmental demyelination occurs, individual segments, represented by the length of axon covered by one Schwann cell, lose their myelin sheaths but the axons are preserved. This differs from Wallerian degeneration where myelin destruction occurs along the length of a nerve fibre following death of the axon.In experimental diphtheritic neuropathy, an acute segmental demyelinating disease, lysosomes accumulate within the Schwann cells prior to disruption of the myelin sheath; furthermore, the site of initial myelin breakdown appears to be closely related to the collections of lysosomes. The Schwann cell starts to form a new myelin sheath around the axon probably within a few hours of the destruction of the original myelin sheath, and while the latter is being catabolised within lysosomal vacuoles This stage of remyelination follows a similar course to primary myelination, so that the recovery stage is characterised by normal axons with either no myelin, or surrounded by sheaths that are very thin relative to the diameter of the axon.

Periaxin expression in myelinating Schwann cells: modulation by axon-glial interactions and polarized localization during development

Development ◽  
1995 ◽  
Vol 121 (12) ◽  
pp. 4265-4273 ◽  
Author(s):  
S.S. Scherer ◽  
Y.T. Xu ◽  
P.G. Bannerman ◽  
D.L. Sherman ◽  
P.J. Brophy
Keyword(s):  
Cell Membrane ◽  
Membrane Protein ◽  
Schwann Cell ◽  
Schwann Cells ◽  
Protein Interactions ◽  
Myelin Sheath ◽  
Myelin Proteins ◽  
Developmentally Regulated ◽  
Protein Levels ◽  
Myelin Sheaths

Periaxin is a newly described protein that is expressed exclusively by myelinating Schwann cells. In developing nerves, periaxin is first detected as Schwann cells ensheathe axons, prior to the appearance of the proteins that characterize the myelin sheath. Periaxin is initially concentrated in the adaxonal membrane (apposing the axon) but, during development, as myelin sheaths mature, periaxin becomes predominately localized at the abaxonal Schwann cell membrane (apposing the basal lamina). In permanently axotomized adult nerves, periaxin is lost from the abaxonal and adaxonal membranes, becomes associated with degenerating myelin sheaths and is phagocytosed by macrophages. In crushed nerves, in which axons regenerate and are remyelinated, periaxin is first detected in the adoxonal membrane as Schwann cells ensheathe regenerating axons, but again prior to the appearance of other myelin proteins. Periaxin mRNA and protein levels change in parallel with those of other myelin-related genes after permanent axotomy and crush. These data demonstrate that periaxin is expressed by myelinating Schwann cells in a dynamic, developmentally regulated manner. The shift in localization of periaxin in the Schwann cell after completion of the spiralization phase of myelination suggests that periaxin participates in membrane-protein interactions that are required to stabilize the mature myelin sheath.

scholarly journals LPA1 signaling drives Schwann cell dedifferentiation in experimental autoimmune neuritis

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Fabian Szepanowski ◽  
Maximilian Winkelhausen ◽  
Rebecca D. Steubing ◽  
Anne K. Mausberg ◽  
Christoph Kleinschnitz ◽  
...  
Keyword(s):  
Sciatic Nerve ◽  
Schwann Cell ◽  
Schwann Cells ◽  
Cell Physiology ◽  
Receptor Subtype ◽  
Experimental Autoimmune Neuritis ◽  
Thin Sections ◽  
Lewis Rats ◽  
Inflammatory Neuropathies ◽  
Experimental Autoimmune

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.

scholarly journals Expression of P30, a protein with adhesive properties, in Schwann cells and neurons of the developing and regenerating peripheral nerve.

1991 ◽  
Vol 112 (6) ◽  
pp. 1229-1239 ◽  
Author(s):  
M M Daston ◽  
N Ratner
Keyword(s):  
Nervous System ◽  
Schwann Cell ◽  
Schwann Cells ◽  
Dorsal Root Ganglion Neurons ◽  
Cell Contact ◽  
Heparin Binding ◽  
Adhesive Properties ◽  
Ganglion Neurons ◽  
Developing Rat

P30 is a heparin-binding protein with adhesive and neurite outgrowth-promoting properties present at high levels in the developing rat central nervous system (Rauvala, H., and R. Pihlaskari. 1987 J. Biol. Chem. 262:16625-16635). Partial sequencing of p30 has revealed homology or identity with HMG-1 (Rauvala, H., J. Merenmies, R. Pihlaskari, M. Korkolainen, M.-L. Huhtala, and P. Panula. 1988. J. Cell Biol. 107:2292-2305), a 28-kD protein that was originally purified from the thymus (Goodwin, G.H., C. Sanders, and E. W. Johns. 1973. Eur. J. Biochem. 38:14-19) which binds DNA in vitro. We have analyzed the distribution of p30 in the developing rat peripheral nervous system (PNS). P30 was detected by immunohistochemistry and Western blot analysis using antibodies raised against intact p30 and against a synthetic peptide corresponding to the amino terminus of the p30 molecule. P30 was localized to nonnuclear compartments of neurons and peripheral glial cells (Schwann cells). P30 immunoreactivity of PNS neurons persisted into adulthood. In contrast, Schwann cell staining decreased after the second postnatal week and was not detectable in adult animals. Neuron-Schwann cell contact was correlated with diminished p30 levels in Schwann cells. Schwann cells of the normal adult sciatic nerve did not express p30; however, when deprived of axonal contact by nerve transection, the Schwann cells of the distal nerve stained intensely for p30. In addition, when Schwann cells and dorsal root ganglion neurons were grown in coculture, Schwann cells that were associated with neurites were not as intensely stained by anti-p30 as Schwann cells that were not in contact with neurons. The pattern of p30 expression during development and regeneration, and its apparent regulation by cell-cell contact suggests that p30 plays a role in the interaction between neurons and Schwann cells during morphogenesis of peripheral nerves.

scholarly journals THE FINE STRUCTURE OF NERVE CELL BODIES AND THEIR MYELIN SHEATHS IN THE EIGHTH NERVE GANGLION OF THE GOLDFISH

1961 ◽  
Vol 9 (4) ◽  
pp. 853-877 ◽  
Author(s):  
Jack Rosenbluth ◽  
Sanford L. Palay
Keyword(s):  
Schwann Cell ◽  
Nerve Cell ◽  
Single Layer ◽  
Intermediate Form ◽  
Cell Cytoplasm ◽  
Eighth Cranial Nerve ◽  
Myelin Sheaths ◽  
Nerve Ganglion ◽  
The One ◽  
Internodal Segment

The eighth cranial nerve ganglion consists of bipolar nerve cell bodies each occupying part of an internodal segment. The perikaryal sheaths range from a single layer of Schwann cell cytoplasm on the smallest cells to typical thick compact myelin on the largest. On most perikarya, the sheath displays an intermediate form, consisting of multiple layers of Schwann cell cytoplasm (loose myelin), or of loose and compact myelin continuous with each other. Internodes beyond the one containing the cell body bear only compact myelin. In loose myelin the thickness of each layer of Schwann cell cytoplasm is about 100 A. It may be much greater (∼ 3000 A) particularly in the outermost layers of the sheath, or the cytoplasm may thin and even disappear with formation of a major dense line. The cytoplasmic layers are separated from each other by a light zone, 40 to 200 A wide, which in its broader portions may contain an intermediate line. Desmosomes sometimes occur between lamellae. In addition to the usual organelles, the perikaryal cytoplasm contains granular and membranous inclusions. Large cells covered by compact myelin have a consistently higher concentration of neurofilaments, and some of the largest cells, in addition, show a reduced concentration of ribosomes. The functional significance and possible origins of perikaryal myelin sheaths are discussed.

scholarly journals Schwann Cell Myelination Requires Timely and Precise Targeting of P0 Protein

2000 ◽  
Vol 148 (5) ◽  
pp. 1009-1020 ◽  
Author(s):  
X. Yin ◽  
G.J. Kidd ◽  
L. Wrabetz ◽  
M.L. Feltri ◽  
A. Messing ◽  
...  
Keyword(s):  
Schwann Cell ◽  
Schwann Cells ◽  
Structural Protein ◽  
Major Structural Protein ◽  
Adult Mice ◽  
Pns Myelin ◽  
P0 Protein ◽  
Dynamic Membranes ◽  
Myelin Associated Glycoprotein ◽  
Homophilic Adhesion

This report investigated mechanisms responsible for failed Schwann cell myelination in mice that overexpress P0 (P0tg), the major structural protein of PNS myelin. Quantitative ultrastructural immunocytochemistry established that P0 protein was mistargeted to abaxonal, periaxonal, and mesaxon membranes in P0tg Schwann cells with arrested myelination. The extracellular leaflets of P0-containing mesaxon membranes were closely apposed with periodicities of compact myelin. The myelin-associated glycoprotein was appropriately sorted in the Golgi apparatus and targeted to periaxonal membranes. In adult mice, occasional Schwann cells myelinated axons possibly with the aid of endocytic removal of mistargeted P0. These results indicate that P0 gene multiplication causes P0 mistargeting to mesaxon membranes, and through obligate P0 homophilic adhesion, renders these dynamic membranes inert and halts myelination.

scholarly journals Incorporation of newly formed lecithin into peripheral nerve myelin.

1976 ◽  
Vol 68 (3) ◽  
pp. 480-496 ◽  
Author(s):  
R M Gould ◽  
R M Dawson
Keyword(s):  
Sciatic Nerve ◽  
Schwann Cell ◽  
Peripheral Nerve ◽  
Intraperitoneal Injection ◽  
Axoplasmic Transport ◽  
Cell Cytoplasm ◽  
Neuronal Perikaryon ◽  
Myelin Sheaths ◽  
Adult Mice ◽  
Frog Sciatic Nerve

Radioactive choline was used to study the metabolism and movement of choline-containing phospholipids in peripheral nerve myelin of adult mice. Incorporation at various times after intraperitoneal injection was measured in serial segments of sciatic nerve as well as in myelin isolated from those segments. At no time (1 h to 35 days) could a proximal-distal difference in the extent of labeling be demonstrated. This finding suggests that incorporation of precursor choline phospholipids into nerve membranes is a local event, with little contribution from the neuronal perikaryon via axoplasmic transport. Autoradiographic investigations were undertaken to elucidate the pattern of movement of radioactive choline-labeled phospholipids, predominantly lecithin, into the myelin sheaths of the sciatic nerve. A sequence of autoradiographs was prepared from animals sacrificed between 20 min and 35 days after a microinjection of precursor directly into the nerve. Analysis of these autoradiograms revealed that labeling is initially concentrated in the Schwann cell cytoplasm. Later, the label moves first into the outer regions of the myelin sheaths and is eventually distributed evenly throughout the inner and outer layers of the sheath. At no time is there a build-up of label in the axon. The rate of uptake of precursor and subsequent redistribution of lecithin into the myelin were also examined in frog sciatic nerve (18 degrees C). Both uptake and redistribution processes were considerably slower in the cold-blooded animal.

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