The role of glycosaminoglycans in anuran pigment cell migration

Development ◽  
1986 ◽  
Vol 92 (1) ◽  
pp. 145-164
Author(s):  
R. P. Tucker

The migratory pathways of neural crest-derived pigment cells were examined in two anurans, Xenopus laevis and Discoglossus pictus, and correlated with the distribution of glycosaminoglycans (GAG) in the extracellular matrix (ECM) of these pathways. In Xenopus, melanophores in the trunk reach the dermis by initially migrating ventrally, between the neural tube and somites, and then by migrating through the somites to reach the subectodermal space. In Discoglossus, melanophores, iridophores, and xanthophores migrate laterally over the dorsal margin of the somites to reach the dermis. GAG was identified in the light microscope using alcian blue staining and in the electron microscope using ruthenium red staining. The ECM at the dorsal entrance to the lateral pathway in Xenopus and in young Discoglossus (at a stage prior to invasion by pigment cells) is filled with 25–50 nm chondroitin sulphate proteoglycan aggregates. When this ECM in Xenopus is digested in vivo with chondroitinase ABC, melanophores enter the lateral pathway. In older Discoglossus embryos, the migration of pigment cells into the lateral pathway is correlated with increases in the space between the ectoderm and somites and in the number of hyaluronate microfibrils. These observations suggest that chondroitin sulphate proteoglycan in the subectodermal ECM restricts the migration of pigment cells into the lateral pathway by limiting the amount of space for migration and possibly by acting as a less adhesive migratory substratum than the ventral pathway, and that in Discoglossus hyaluronate opens spaces permitting the migration of pigment cells directly over the dorsal margin of the somites.

1972 ◽  
Vol 130 (3) ◽  
pp. 729-738 ◽  
Author(s):  
Å. Wasteson ◽  
U. Lindahl ◽  
A. Hallén

1. Chondroitin sulphate was isolated from different regions of rat costal cartilage after extensive proteolysis of the tissues. The molecular weight, determined by gel chromatography, of the polysaccharide obtained from an actively growing region (lateral zone) near the osteochondral junction was higher than that of the polysaccharide isolated from the remaining portion of the costal cartilage (medial zone). 2. In both types of cartilage the molecular weight of chondroitin sulphate, labelled with [35S]sulphate, remained unchanged in vivo over a period of 10 days, approximately corresponding to the half-life of the chondroitin sulphate proteoglycan. The molecular-weight distribution of chondroitin [35S]sulphate, labelled in vivo or in vitro, was invariably identical with that of the bulk polysaccharide from the same tissue. It is concluded that the observed regional variations in molecular-weight distribution were established at the time of polysaccharide biosynthesis. 3. In tissue culture more than half of the 35S-labelled polysaccharide–proteins of the two tissues was released into the medium within 10 days of incubation. The released materials were of smaller molecular size than were the corresponding native proteoglycans. In contrast, the molecular-weight distribution of the chondroitin [35S]sulphate (single polysaccharide chains) remained constant throughout the incubation period. 4. A portion (about 20%) of the total radioactive material released from 35S-labelled cartilage in tissue culture was identified as inorganic [35S]sulphate. No corresponding decrease in the degree of sulphation of the labelled polysaccharide could be detected. These findings suggest that a limited fraction of the proteoglycan molecules had been extensively desulphated. 5. It is suggested that the initial phase of degradation involves proteolytic cleavage of the proteoglycan, but the constituent polysaccharide chains remain intact. The partially degraded proteoglycan may be eliminated from the cartilage by diffusion into the circulatory system. An additional degradative process, which may occur intracellularly, includes desulphation of the polysaccharide, probably in conjunction with a more extensive breakdown of the polymer.


Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1538 ◽  
Author(s):  
Marta Mellai ◽  
Laura Annovazzi ◽  
Ilaria Bisogno ◽  
Cristiano Corona ◽  
Paola Crociara ◽  
...  

Background: Neuron glial antigen 2 or chondroitin sulphate proteoglycan 4 (NG2/CSPG4) is expressed by immature precursors/progenitor cells and is possibly involved in malignant cell transformation. The aim of this study was to investigate its role on the progression and survival of sixty-one adult gliomas and nine glioblastoma (GB)-derived cell lines. Methods: NG2/CSPG4 protein expression was assessed by immunohistochemistry and immunofluorescence. Genetic and epigenetic alterations were detected by molecular genetic techniques. Results: NG2/CSPG4 was frequently expressed in IDH-mutant/1p19q-codel oligodendrogliomas (59.1%) and IDH-wild type GBs (40%) and rarely expressed in IDH-mutant or IDH-wild type astrocytomas (14.3%). Besides tumor cells, NG2/CSPG4 immunoreactivity was found in the cytoplasm and/or cell membranes of reactive astrocytes and vascular pericytes/endothelial cells. In GB-derived neurospheres, it was variably detected according to the number of passages of the in vitro culture. In GB-derived adherent cells, a diffuse positivity was found in most cells. NG2/CSPG4 expression was significantly associated with EGFR gene amplification (p = 0.0005) and poor prognosis (p = 0.016) in astrocytic tumors. Conclusion: The immunoreactivity of NG2/CSPG4 provides information on the timing of the neoplastic transformation and could have prognostic and therapeutic relevance as a promising tumor-associated antigen for antibody-based immunotherapy in patients with malignant gliomas.


Development ◽  
1986 ◽  
Vol 94 (1) ◽  
pp. 189-205
Author(s):  
Betty C. Gallagher

The developing chick lung was examined in the electron microscope for intimate cell contacts between epithelium and mesenchyme, discontinuities in the basal lamina and substructure of the basement membrane. Cell filopodia were seen which crossed the basal lamina from both the epithelial and the mesenchymal cells. Ruthenium red and tannic acid staining of the basal lamina of the chick lung showed it to be thin and sometimes discontinuous at the tips compared to the more substantial basal lamina in the interbud areas. The bilaminar distribution of particles seen with ruthenium red is similar to those seen in the cornea and lens. With tannic acid staining, filaments could be seen which crossed the lamina lucida and connected with the lamina densa. Spikes perpendicular to the basal lamina were sometimes seen with a periodicity of approximately 110 nm. Alcian blue staining revealed structure similar to that seen by ruthenium red staining in the salivary and mammary glands, although the interparticle spacing was closer. Collagen was located in areas of morphogenetic stability, as has been seen by other investigators in different tissues. Collagen was coated with granules (probably proteoglycan) at periodic intervals when stained with ruthenium red. The fibrils were oriented circumferentially around the mesobronchus and were assumed to continue into the bud, but the fibres curve laterally at the middle of a bud. This orientation is opposite to that seen by another investigator in the mouse lung. In general, the observations made in the avian lung are similar to those seen in branching mammalian tissue. It is likely, therefore, that the chick lung uses strategies in its morphogenesis that are similar to those that have been elucidated previously in developing mammalian organs.


1986 ◽  
Vol 235 (2) ◽  
pp. 469-479 ◽  
Author(s):  
B C Wightman ◽  
E A Weltman ◽  
L A Culp

Proteoglycans on the cell surface play critical roles in the adhesion of fibroblasts to a fibronectin-containing extracellular matrix, including the model mouse cell line Balb/c 3T3. In order to evaluate the biochemistry of these processes, long-term [35S]sulphate-labelled proteoglycans were extracted quantitatively from the adhesion sites of 3T3 cells, after their EGTA-mediated detachment from the substratum, by using an extractant containing 1% octyl glucoside, 1 M-NaCl and 0.5 M-guanidinium chloride (GdnHCl) in buffer with many proteinase inhibitors. Greater than 90% of the material was identified as a large chondroitin sulphate proteoglycan (Kav. = 0.4 on a Sepharose CL2B column), and the remainder was identified as a smaller heparan sulphate proteoglycan; only small amounts of free chains of glycosaminoglycan were observed in these sites. These extracts were fractionated on DEAE-Sepharose columns under two different sets of elution conditions: with acetate buffer (termed DEAE-I) or with acetate buffer supplemented with 8 M-urea (termed DEAE-II). Under DEAE-I conditions about one-half of the material was eluted as a single peak and the remainder required 4 M-GdnHCl in order to recover it from the column; in contrast, greater than 90% of the material was eluted as a single peak from DEAE-II columns. Comparison of the elution of [35S]sulphate-labelled proteoglycan with that of 3H-labelled proteins from these two columns, as well as mixing experiments, indicated that the GdnHCl-sensitive proteoglycans were trapped at the top of columns, partially as a consequence of their association with proteins in these adhesion-site extracts. Affinity chromatography of these proteoglycans on columns of either immobilized platelet factor 4 or immobilized plasma fibronectin revealed that most of the chondroitin sulphate proteoglycan and the heparan sulphate proteoglycan bound to platelet factor 4 but that only the heparan sulphate proteoglycan bound to fibronectin, providing a ready means of separating the two proteoglycan classes. Affinity chromatography on octyl-Sepharose columns to test for hydrophobic domains in their core proteins demonstrated that a high proportion of the heparan sulphate proteoglycan but none of the chondroitin sulphate proteoglycan bound to the hydrophobic matrix. These results are discussed in light of the possible functional importance of the chondroitin sulphate proteoglycan in the detachment of cells from extracellular matrix and in light of previous affinity fractionations of proteoglycans from the substratum-adhesion sites of simian-virus-40-transformed 3T3 cells.


2001 ◽  
Vol 39 (2) ◽  
pp. 99-104 ◽  
Author(s):  
Yoshihiro Abiko ◽  
Michiko Nishimura ◽  
Firoz Rahemtulla ◽  
Itaru Mizoguchi ◽  
Tohru Kaku

1984 ◽  
Vol 221 (3) ◽  
pp. 845-853 ◽  
Author(s):  
B Norling ◽  
B Glimelius ◽  
A Wasteson

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.


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