Monoclonal antibodies against chondroitin sulphate isomers: their use as probes for investigating proteoglycan metabolism

Abstract

820BIOCHEMICAL SOCIETY TRANSACTIONS tion staining, and indicated that in all probability BMCSPG is absent from the mature glomerular capillary loop. Our data suggest, therefore, that BMCSPG does not have an obligatory structural role in terms of basement membrane assembly, as has been proposed for the large HSPG. Neither does BMCSPG appear to have a role in regulating glomerular permselectivity.We are currently studying kidney development to monitor the appearance and distribution of BMCSPG. Early data support our findings in rat skin [ 121, which showed that this basement membrane component, unlike many others, is strongly developmentally regulated. BMCSPG staining is absent from newly formed basement membranes surrounding early post-induction structures, but appears later at the time of vascular invasion. It may also be that the proteoglycan is transiently expressed in the glomerular basement membrane around the time of its maturation. Its presence, therefore, coincides with the completion of morphogenetic events, and indicates that BMCSPG has a role in basement membrane stability. Such a hypothesis is supported by a study of patients with dystrophic forms of epidermolysis bullosa, where basement membrane chondroitin sulphate was shown to be absent or present to a much reduced extent [ 131. In contrast, antibodies to other basement membrane components, including HSPG [ 131 stained the skin basement membranes of dystrophic epidermolysis bullosa patients normally. Characteristically, these patients have skin basement membrane fragility with cleavage from the underlying dermis. It therefore appears that a specific defect in BMCSPG expression correlates with severe basement membrane abnormality.Finally, the lack of BMCSPG in the normal adult rat glomerular capillary loop raised the question of potential abnormality in diabetes, where mesangial expansion and thickening of the capillary loop and other basement membranes is a corollary of the disease process. Indeed our preliminary data with a streptotozocin model of diabetes in the rat indicate that BMCSPG is abnormally expressed in the kidney glomerulus of rats which have been diabetic for 2 months. It seems, therefore, that although a minor basement membrane component, BMCSPG may be important in development and some diseases where basement membrane integrity or stability are compromised.Chondroitin sulphate (CS) proteoglycans are major components of cartilage and lesser constituents of many other connective tissues. Current literature indicates that the major biomechanical functions of the polyanionic CS glycosaminoglycan chains of the cartilage proteoglycans are to contribute towards maintenance of a Donnan osmotic pressure within the cartilage, to participate in excluded volume effects and to contribute to the viscoelastic properties of the tissue (see [ 1-31 for reviews). Biochemical analysis of articular cartilage proteoglycans indicates that expression of different isomeric forms of CS occurs during normal growth and development, and in pathology [4-61. The pu...

Chondroitin sulfate proteoglycans in the developing cerebral cortex: The distribution of neurocan distinguishes forming afferent and efferent axonal pathways

“…We have grouped our findings into five sections based on the distribution of immunolabeling during cortical development: 1) comparison of the distribution of the central nervous system (CNS)-specific proteoglycan neurocan (Rauch et al, 1991(Rauch et al, , 1992 with that of chondroitin sulfate glycosaminoglycan chains identified with the CS-56 antibody; neurocan is the only CSPG core protein in our panel that we found to have a distinct laminar distribution during early stages and to be particularly prominent in the subplate; 2) distribution of chondroitin disaccharides that are either unsulfated or sulfated in the 4 or 6 position of N-acetylgalactosamine in the oligosaccharide stub that remains after c U B C digestion (Caterson et al, 1990); 3) proteoglycan core proteins that do not have a laminar pattern but, instead, are widely distributed in early stages; 4) CSPGs that are associated with nonneuronal structures such as blood vessels or with axons in late development; and 5 ) distribution of CSPGs in the barrel field of the postnatal somatosensory cortex, where it has been previously demonstrated that tenascin and the cytotactin binding proteoglycan are more prominent in the barrel walls than in the centers of the barrels (Crossin et al, 1989;Steindler et al, 1989;Jhaveri et al, 1991;Sheppard et al, 1991). Although it is not possible to determine the subcellular localization of proteoglycans with certainty using light microscopic immunolabeling, we have attempted to identify labeling of the cytoplasm (see, e.g., Fig.…”

“…Epitopes on the core protein are unaffected by chABC treatment (e.g., neurocan; Table 1). The terminal disaccharides recognized by the antibodies to unsulfated and 4-and 6-sulfated chondroitin require chABC treatment (Caterson et al, 1990), but the antibody to chondroitin 4-sulfate (2B6) also recognizes a cytoplasmic component without chABC treatment (see Results).…”

“…Chondroitinase ABC digestion removes the majority of the glycosaminoglycan chain, leaving oligosaccharide stubs that are either unsulfated or sulfated in the 4 or 6 position of N-acetylgalactosamine (Caterson et al, 1990). To determine the distribution of three of these isomers in the developing cortex, we used monoclonal antibodies that recognize distinct epitopes in the CS oligosaccharide stub that results from chABC digestion.…”

Immunolocation analysis of glycosaminoglycans in the human growth plate.

“…The epitope specificities of the antibodies used in this analysis are described in part in Eble 1 and more fully elsewhere (3)(4)(5)(6)(7)(17)(18)(19), and the following dilutions were …”

Two Related but Distinct Chondroitin Sulfate Mimetope Octasaccharide Sequences Recognized by Monoclonal Antibody WF6

“…Monoclonal antibodies (mAbs) have been generated that recognize specific features of CS chains (10), but few of the epitopes have been characterized in detail (11)(12)(13). Studies with anti-CS mAbs have revealed restricted spatio-temporal patterns of expression in various tissues during growth and development and in pathological conditions (14 -17).…”