Integrated interactions between chondroitin sulphate proteoglycans and weak dc electric fields regulate nerve growth cone guidance in vitro

1997 ◽  
Vol 110 (16) ◽  
pp. 1957-1965
Author(s):  
L. Erskine ◽  
C.D. McCaig
Keyword(s):  
Electric Fields ◽  
Growth Cone ◽  
Chondroitin Sulphate ◽  
Side Chains ◽  
Keratan Sulphate ◽  
Nerve Growth ◽  
Guidance Cues ◽  
Chondroitin Sulphate Proteoglycans ◽  
Growth Cone Guidance

During development and regenerative growth, neuronal pathways are defined in part by several endogenous cues that collectively determine directed growth. The interactions between such cues largely are unknown. To address potential interactions, we have examined in vitro the combined effect on nerve growth of two endogenous growth cone guidance cues: chondroitin sulphate proteoglycans and weak dc electric fields. Addition to the culture medium of a chondroitin 6-sulphate/keratan sulphate containing PG (BNC-PG) markedly enhanced the cathodal re-orientation of embryonic Xenopus neurites in an electric field, whereas a proteoglycan containing chondroitin 4-sulphate (RC-PG) was inhibitory. These effects of BNC-PG and RC-PG were reproduced by their chondroitin sulphate glycosaminoglycan side chains alone. Chondroitin 6-sulphate or chondroitin 4-sulphate, respectively, enhanced and inhibited cathodally-directed nerve re-orientation. This was dependent on the integrity of the glycosaminoglycan chain structure; when digested into their disaccharide subunits both molecules became inactive. Keratan sulphate, a minor component of BNC-PG, was found to be inhibitory, whereas dermatan sulphate, an epimer of chondroitin 4-sulphate, had no effect. We conclude that in vitro specific interactions between these two nerve guidance cues do occur and that the specificity of the response is critically dependent on the charge pattern of the proteoglycans chondroitin sulphate side chains. The expression of a host of proteoglycans with differing glycosaminoglycan side chains varies in both time and place in the developing nervous system, thus the scope is vast for spatial and temporal modulation of nerve guidance by interacting cues.

scholarly journals A chondroitin sulphate proteoglycan from human cultured glial and glioma cells. Structural and functional properties

1984 ◽  
Vol 221 (3) ◽  
pp. 845-853 ◽  
Author(s):  
B Norling ◽  
B Glimelius ◽  
A Wasteson
Keyword(s):  
Hyaluronic Acid ◽  
Chondroitin Sulphate ◽  
Buoyant Density ◽  
Glioma Cells ◽  
Keratan Sulphate ◽  
Link Protein ◽  
Sulphate Proteoglycan ◽  
Chondroitin Sulphate Proteoglycan ◽  
Chondroitin Sulphate Proteoglycans ◽  
Structural And Functional Properties

A chondroitin sulphate proteoglycan capable of forming large aggregates with hyaluronic acid was identified in cultures of human glial and glioma cells. The glial- cell- and glioma-cell-derived products were mutually indistinguishable and had some basic properties in common with the analogous chondroitin sulphate proteoglycan of cartilage: hydrodynamic size, dependence on a minimal size of hyaluronic acid for recognition, stabilization of aggregates by link protein, and precipitability with antibodies raised against bovine cartilage chondroitin sulphate proteoglycan. However, they differed in some aspects: lower buoyant density, larger, but fewer, chondroitin sulphate side chains, presence of iduronic acid-containing repeating units, and absence (less than 1%) of keratan sulphate. Apparently the major difference between glial/glioma and cartilage chondroitin sulphate proteoglycans relates to the glycan rather than to the protein moiety of the molecule.

scholarly journals Biosynthesis of glycosaminoglycans in bovine cornea. The effect of uridine diphosphate xylose

1970 ◽  
Vol 120 (4) ◽  
pp. 719-723 ◽  
Author(s):  
C. Balduini ◽  
A. Brovelli ◽  
A. A. Castellani
Keyword(s):  
Glucuronic Acid ◽  
Chondroitin Sulphate ◽  
Glucose Dehydrogenase ◽  
Uridine Diphosphate ◽  
Regulatory Effect ◽  
Keratan Sulphate ◽  
Polysaccharide Chain

1. The role of UDP-xylose in the regulation of corneal glycosaminoglycan biosynthesis was investigated. Bovine corneas were incubated with [U-14C]-glucose in the presence and in the absence of the nucleotide, and the radioactivity of chondroitin, chondroitin sulphate and keratan sulphate, as well as of their monosaccharide constituents, was determined. 2. A decrease in the rate of biosynthesis of chondroitin and chondroitin sulphate and an increase in that of keratan sulphate were observed in the samples incubated with UDP-xylose. 3. The UDP-glucuronic acid isolated after the incubation in the presence of UDP-xylose showed a noticeable decrease in the amount of radioactivity incorporated; this result suggests that UDP-xylose inhibits the UDP-glucose dehydrogenase, causing an accumulation of UDP-glucose and consequently an increase in the formation of UDP-galactose and keratan sulphate. 4. Galactose and galactosamine isolated from the polysaccharides showed variations in the amount of radioactivity incorporated in accordance with those observed for the macromolecules; this fact confirms that in the system we used in vitro a real biosynthesis of the polysaccharide chain took place and that the regulatory effect of UDP-xylose was active at the monosaccharide level.

scholarly journals Tubulin is phosphorylated at tyrosine by pp60c-src in nerve growth cone membranes.

1990 ◽  
Vol 111 (5) ◽  
pp. 1959-1970 ◽  
Author(s):  
W T Matten ◽  
M Aubry ◽  
J West ◽  
P F Maness
Keyword(s):  
Growth Cone ◽  
Cortical Neurons ◽  
Specific Protein ◽  
Beta Tubulin ◽  
Nerve Growth ◽  
Alpha Tubulin ◽  
Nerve Growth Cone ◽  
Phosphopeptide Mapping

We show here that tubulin is the major in vivo substrate of the tyrosine-specific protein kinase pp60c-src in nerve growth cone membranes. Phosphotyrosine antibodies were used to demonstrate phosphotyrosyl residues in a subpopulation of alpha- and beta-tubulin that was highly enriched in a subcellular fraction of growth cone membranes from fetal rat brain. The presence of phosphotyrosine-modified isoforms of alpha- and beta-tubulin in vivo was confirmed by 32p labeling of rat cortical neurons in culture. Tubulin in growth cone membranes was phosphorylated at tyrosine in endogenous membrane phosphorylation reactions (0.068 mol phosphotyrosine/mol alpha-tubulin and 0.045 mol phosphotyrosine/mol beta-tubulin), and phosphorylation was specifically inhibited by antibodies directed against pp60c-src, which is localized in the growth cone membranes. pp60c-src was capable of directly phosphorylating tubulin as shown in immune complex kinase assays with purified brain tubulin. Phosphopeptide mapping revealed a limited number of sites of tyrosine phosphorylation in alpha- and beta-tubulin, with similar phosphopeptides observed in vivo and in vitro. These results reveal a novel posttranslational modification of tubulin that could regulate microtubule dynamics at the growth cone.

scholarly journals Gradients and Growth Cone Guidance of Grasshopper Neurons

2003 ◽  
Vol 51 (4) ◽  
pp. 445-454 ◽  
Author(s):  
Arthur T. Legg ◽  
Timothy P. O'Connor
Keyword(s):  
Nervous System ◽  
Long Range ◽  
Growth Cone ◽  
Growth Cones ◽  
Path Finding ◽  
Guidance Cues ◽  
Cone Function ◽  
The Absolute ◽  
Growth Cone Guidance

The generation of a functional nervous system is dependent on precise path-finding of axons during development. This pathfinding is directed by the distribution of local and long-range guidance cues, the latter of which are believed to be distributed in gradients. Gradients of guidance cues have been associated with growth cone function for over a hundred years. However, little is known about the mechanisms used by growth cones to respond to these gradients, in part owing to the lack of identifiable gradients in vivo. In the developing grasshopper limb, two gradients of the semaphorin Sema-2a are necessary for correct neuronal pathfinding in vivo. The gradients are found in regions where growth cones make critical steering decisions. Observations of different growth cone behaviors associated with these gradients have provided some insights into how growth cones respond to them. Growth cones appear to respond more faithfully to changes in concentration, rather than absolute levels, of Sema-2a expression, whereas the absolute levels may regulate growth cone size.

scholarly journals Microtubule behavior during guidance of pioneer neuron growth cones in situ.

1991 ◽  
Vol 115 (2) ◽  
pp. 381-395 ◽  
Author(s):  
J H Sabry ◽  
T P O'Connor ◽  
L Evans ◽  
A Toroian-Raymond ◽  
M Kirschner ◽  
...  
Keyword(s):  
Growth Cone ◽  
Growth Cones ◽  
The Body ◽  
Microtubule Network ◽  
Guidance Cues ◽  
Selective Retention ◽  
Pioneer Neuron ◽  
Neuron Growth

The growth of an axon toward its target results from the reorganization of the cytoskeleton in response to environmental guidance cues. Recently developed imaging technology makes it possible to address the effect of such cues on the neural cytoskeleton directly. Although high resolution studies can be carried out on neurons in vitro, these circumstances do not recreate the complexity of the natural environment. We report here on the arrangement and dynamics of microtubules in live neurons pathfinding in response to natural guidance cues in situ using the embryonic grasshopper limb fillet preparation. A rich microtubule network was present within the body of the growth cone and normally extended into the distal growth cone margin. Complex microtubule loops often formed transiently within the growth cone. Branches both with and without microtubules were regularly observed. Microtubules did not extend into filopodia. During growth cone steering events in response to identified guidance cues, microtubule behaviour could be monitored. In turns towards guidepost cells, microtubules selectively invaded branches derived from filopodia that had contacted the guidepost cell. At limb segment boundaries, microtubules displayed a variety of behaviors, including selective branch invasion, and also invasion of multiple branches followed by selective retention in branches oriented in the correct direction. Microtubule invasion of multiple branches also was seen in growth cones migrating on intrasegmental epithelium. Both selective invasion and selective retention generate asymmetrical microtubule arrangements within the growth cone, and may play a key role in growth cone steering events.

scholarly journals Chondroitin sulphate and keratan sulphate are almost isosteric

1991 ◽  
Vol 275 (1) ◽  
pp. 267-268 ◽  
Author(s):  
J E Scott
Keyword(s):  
Chondroitin Sulphate ◽  
Anionic Sites ◽  
Keratan Sulphate

Keratan sulphate and chondroitin sulphate (KS and CS) in the 2-fold helical configurations that are prevalent in solution are of very similar tacticity. The chiral centres, anionic sites and hydrophobic patches are in identical conformations. Only the position of the acetamido group varies from CS to KS, but part of its intramolecular H-bonding potential in CS is retained in KS. The formation of tertiary aggregates, observed in vitro and in tissues, is explicable on these bases. The proposal that KS may be a functional substitute for CS [Scott & Haigh (1988) J. Anat. 158, 95-108] under low-O2 conditions is relevant.

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