Impaired synthesis of intracellular heparan sulfate in skin fibroblasts of Lowe's syndrome.

Synthesis and distribution pattern of intracellular GAG were evaluated skin fibroblasts cultured from two patients with Lowe's syndrome and control children. After trypsinization and Pronase treatment of fibroblasts at around the tenth generation of passage and at the stage of culture confluence, GAG were isolated by precipitation with CPC in the presence of 0.25M NaCl and analyzed by cellulose acetate electrophoresis in 0.05M barium acetate buffer. Relative proportion of intracellular heparan sulfate was about 20% of total in Lowe's syndrome fibroblasts and 35% to 40% in control fibroblasts. Incorporation experiments with labeled precursors showed that [35S]sulfate incorporation into intracellular heparan sulfate of Lowe's syndrome was about half that of controls. There were no significant differences in [38S]sulfate uptake into dermatan sulfate and chondroitin sulfate isomers between Lowe's syndrome and control fibroblasts. The results of incorporation experiment with [14C]glucosamine were essentially the same as with [35S]sulfate. There was no apparent tendency for undersulfation in intracellular sulfated GAG of Lowe's syndrome fibroblasts. These results suggested that impaired synthesis, rather than defective sulfation, of intracellular heparan sulfate might characterize one of the metabolic aberrations in Lowe's syndrome fibroblasts.