chondroitin-sulfates and Retinal-Degeneration

One major aspect of the aging process is the onset of chronic, low-grade inflammation that is highly associated with age-related diseases. The molecular mechanisms that regulate these processes have not been fully elucidated. We have identified a spontaneous mutant mouse line, small with kinky tail (

Topics: Age Factors; Animals; Apoptosis; Chondroitin Sulfates; Female; Glucuronosyltransferase; Inflammation; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Multifunctional Enzymes; Mutation; N-Acetylgalactosaminyltransferases; Neurodegenerative Diseases; Neurons; Protein Processing, Post-Translational; Proteins; Retinal Degeneration

The basement membrane is crucial for cell polarity, adhesion, and motility, but how it is assembled on the cell surface remains unclear. Here, we find that ablation of glycosaminoglycan (GAG) side chains of proteoglycans in the neuroretina disrupts the retinal basement membrane, leading to arrested astrocyte migration and reduced angiogenesis. Using genetic deletion and time-lapse imaging, we show that retinal astrocytes require neuronal-derived PDGF as a chemoattractive cue and the retinal basement membrane as a migratory substrate. Genetic ablation of heparan sulfates does not produce the same defects as GAG null mutants. In contrast, enzymatic removal of heparan sulfates and chondroitin sulfates together inhibits de novo laminin network assembly. These results indicate that both heparan and chondroitin sulfate proteoglycans participate in retinal basement membrane assembly, thus promoting astrocyte migration and angiogenesis.

Topics: Animals; Astrocytes; Basement Membrane; Cell Differentiation; Cell Movement; Chondroitin Sulfates; Heparitin Sulfate; Mice; Mutation; Neovascularization, Physiologic; Neurons; Organ Specificity; Platelet-Derived Growth Factor; Proteoglycans; ras Proteins; Receptors, Cell Surface; Retina; Retinal Degeneration; Signal Transduction; Uridine Diphosphate Glucose Dehydrogenase

The RCS rat is a widely studied model of human retinal dystrophies including retinitis pigmentosa. Chondroitin-6-sulphate (C6S) in the interphotoreceptor matrix was localised immunocytochemically in both the normal congenic and dystrophic strains of the RCS rat up to 65 days postnatally. From postnatal days 5 to 15 the distribution of C6S in both strains was similar, being localised in the interstices of developing inner and outer segments and adjacent to the RPE surface. In the normal rats, the distribution of C6S did not change with age. In the RCS rats, however, at postnatal days 20 to 35 staining was observed as a dense band at the junction of inner and outer segments and no staining was observed adjacent to the surface of the RPE. At postnatal day 45 onwards there was a decrease and a complete absence of C6S staining in these rats. This change in the pattern of staining correlated with the morphological observation of the progressive degeneration of photoreceptor cells suggesting that C6S may be important in photoreceptor degeneration in the RCS rat.

Topics: Aging; Animals; Antibodies, Monoclonal; Chondroitin Sulfates; Image Processing, Computer-Assisted; Immunoenzyme Techniques; Photoreceptor Cells; Pigment Epithelium of Eye; Rats; Rats, Mutant Strains; Retina; Retinal Degeneration; Retinitis Pigmentosa

The distribution of sulfated proteoglycans in the interphotoreceptor matrix (IPM) was examined during development and degeneration of photoreceptors in the rds mouse with electron microscopy after staining with the cationic dye Cupromeronic Blue (CmB). Three distinct CmB-positive filaments types were observed: type A (45-55 nm long and around 5 nm in diameter), type B (up to 0.5 micron long and 5-10 nm in diameter), and type C filaments (up to 1 micron long and 15-25 nm in diameter. During early postnatal development, before degenerative changes occur in photoreceptors, CmB-positive filaments were virtually identical in morphology and pattern of development as those recently reported for the normal mouse IPM (Tawara, Varner and Hollyfield, 1989, Exp. Eye Res. 48, 815-39). From 10 days to 1 year of age, during the period of progressive degeneration and loss of photoreceptor cells, numerous type B and type C filaments were present in the IPM. Type B filaments were distributed throughout the IPM, whereas type C were predominantly located around the apical termination of photoreceptor inner segments and between the pigment epithelial microvilli. Type A filaments were located principally in the apical cytoplasm of the pigment epithelial cells and in the proximal IPM. In the 20-month-old rds mouse, a time when virtually no photoreceptor cells remain, only minimal CmB staining was evident at the interface between the pigment epithelium and retina. Pretreatment with chondroitinase AC eliminated most CmB-positive filaments from the 18-day-old and 20-month-old mouse IPM. These findings suggest that there are no major differences in structural type or early postnatal development of chondroitin sulfate-type proteoglycans in the IPM between rds and normal mice. Any differences in distribution of chondroitin sulfate-type proteoglycans between rds and normal mice can be accounted for by the absence of photoreceptor outer segments and progressive loss of photoreceptor cells in this mutant. The disappearance of these IPM proteoglycans following photoreceptor degeneration suggests that photoreceptors may be critically involved in the maintenance of these matrix components.

Topics: Animals; Chondroitin Sulfates; Cytoskeleton; Mice; Mice, Mutant Strains; Microscopy, Electron; Photoreceptor Cells; Proteoglycans; Retina; Retinal Degeneration

Localization of chondroitin 6-sulfate (6S) in the interphotoreceptor matrix (IPM) of both normal and RCS rats with inherited retinal dystrophy has been carried out using light and electron microscopic immunogold cytochemistry. In the normal rat, 6S antibody labeling was found in highest concentration at the apical surface of the retinal pigment epithelium (RPE) and between adjacent photoreceptors near their basal inner segment-outer segment junction. In the apical zone, label was localized in the IPM and toward the distal portions of the RPE apical processes. In the basal zone, label was found in the IPM and near the outer plasma membranes of inner and outer segments. Interstitial labeling, between the shafts of outer segments, occurred at much lower concentration than in the apical and basal zones. In all zones, the extent of labeling appeared to be space-dependent; it was most abundant where extracellular spaces were large, and little was present where adjacent cell membranes were contiguous. In the dystrophic rat, apical zone labeling of the RPE apical processes was minimal; instead, the relatively small amount of label that was present was localized primarily in the IPM and within encapsulated spaces of membranous whorls of debris. Label was most concentrated in the basal zone, primarily associated with the IPM within abundant interphotoreceptor spaces, and near the plasma membranes of disorganized inner and outer segments. In isolated eyecups and neural retinas, some labeling persisted after extensive buffer rinses which suggests that chondroitin 6-sulfate is a somewhat insoluble component of the IPM in the rat retina.

Topics: Animals; Antibodies, Monoclonal; Chondroitin; Chondroitin Sulfates; Gold; Immunohistochemistry; In Vitro Techniques; Microscopy, Electron; Photoreceptor Cells; Rats; Rats, Inbred Strains; Retina; Retinal Degeneration

The interphotoreceptor matrix (IPM) is a mixture of proteoglycans and glycoproteins through which metabolites must pass in transit between the retinal pigment epithelium (RPE) and the photoreceptor cells. In order to localize various species of chondroitin sulfates in the IPM of the normal and dystrophic rat retina, we have used monoclonal antibodies directed against 6-sulfated chondroitin sulfate (6S), 4-sulfated chondroitin sulfate (4S) and unsulfated chondroitin (0S). Immunofluorescence and immuno-peroxidase methods were carried out on frozen and wax-embedded sections of rat eyes. In the normal rat retina, strong labeling with the 6S antibody was observed in the basal IS/OS zone and, to a lesser extent, in the photoreceptor interstices extending to the apical RPE surface. In the RCS retina, the IPM in the basal IS/OS zone and much of the outer segment debris zone were labeled intensely with 6S antibody, but no strong labeling was present at the apical RPE surface. The labeling pattern with 0S antibody was similar to that of the 6S antibody for both normal and RCS retinas. We failed to detect any 4S antibody labeling of the IPM in both the normal and RCS retinas using these methods. These results indicate that in the rat retina, the IPM contains 6-sulfated chondroitin sulfate and unsulfated chondroitin proteoglycans that are most concentrated in the basal IS/OS zone and, to a lesser degree, between the photoreceptor outer segments. Furthermore, it appears that the rat IPM contains little or no 4-sulfated chondroitin sulfate or dermatan sulfate proteoglycan.

Topics: Animals; Antigens; Chondroitin; Chondroitin Sulfates; Fixatives; Histocytochemistry; Immunochemistry; Photoreceptor Cells; Proteoglycans; Rats; Reference Values; Retinal Degeneration; Tissue Distribution

Systemic findings in a 23-year-old white man with mucolipidosis type IV included early delayed psychomotor development, mental retardation, and mild facial dysplasia. There was urinary excretion of chondroitin sulfate. Ophthalmologic examination showed corneal haze, pigmentary retinopathy, and severe optic atrophy. Light microscopy showed massively engorged superficial and intermediate epithelial cells of both the cornea and the conjunctiva. By transmission electron microscopy these contained fine granular material consistent with acid mucopolysaccharide and concentric lamellar bodies presumably representing phospholipids. This storage phenomenon was also found in macrophages, plasma cells, ciliary epithelial cells, Schwann cells, retinal ganglion cells, and vascular endothelial cells. Light microscopy also disclosed early cataract formation, marked outer retinal degeneration, and optic atrophy.

Topics: Adult; Chondroitin Sulfates; Conjunctiva; Corneal Opacity; Face; Humans; Intellectual Disability; Male; Microscopy, Electron; Mucolipidoses; Optic Atrophy; Psychomotor Disorders; Retinal Degeneration; Retinal Ganglion Cells