Sulfated proteoglycans produced by rat dorsal root ganglion cells

Primary organotypic cultures of embryonic rat dorsal root ganglia, which contain sensory neurons, Schwann cells, and fibroblasts, produce an extensive extracellular matrix. These cultures actively incorporated 35SO4 into glycosaminoglycans, of which 30% were heparan sulfate, 65% chondroitin sulfate, and 5% dermatan sulfate. Sulfate-labeled proteoglycans made by these cells were extracted with 4 M guanidine-hydrochloride and purified by CsCl density gradient centrifugation, gel filtration chromatography, and DEAE-cellulose chromatography. Eight individual species were resolved, of which five were subjected to further analysis. One low-density (less than 1.35 g/ml) proteoglycan, with a Kav on Sepharose Cl-4B = 0.34 contained heparan sulfate chains of Mr = 20,000. The other four proteoglycans, with Kav on Sepharose Cl-4B of 0.04, 0.35 (two), and 0.44, contained predominantly chondroitin sulfate chains with Mr ranging from 30,000 to 40,000. To determine possible functions of these proteoglycans, cultures were grown in medium containing 1 mM 4-methyl-umbelliferyl-beta-D-xyloside. The drug inhibited 35SO4 proteoglycan accumulation in the cell layer by approximately 90%. Drug-treated cultures exhibited several developmental abnormalities, including decreased migration of fibroblast-like cells, abnormal morphology of these cells, and decreased myelination of axons by Schwann cells.