Retinal pigment epithelial glycosaminoglycan metabolism: intracellular versus extracellular pathways. In vitro studies in normal and diseased cells.

摘要: The synthesis and turnover of glycosaminoglycans (GAGs) in different fractions cultured feline retinal pigment epithelium (RPE) were characterized. In one method fractionation, trypsin was used to separate the extracellular components (referred as trypsin-soluble glycocalyx) from intracellular components. As a second method, basal matrix (basal ECM) separated rest GAGs (cell-associated GAGs) by extracting cell layer with NH4OH. incorporation 35SO4 into cetylpyridinium chloride-precipitable cell-associated increased throughout labeling period, while glycocalyx ECM approached maximum. While heparan sulfate predominant GAG all compartments, most located extracellularly. majority dermatan localized fraction. exhibited rapid rate turnover, compartment turned over much more slowly. Ascorbic acid chondroitin sulfate/dermatan sulfate, but not on per basis. Cycloheximide reduced 35SO4-GAGs both ECM. contrast, monensin caused reduction increasing compartment. accumulation resultant pathology alpha-L-iduronidase (alpha-L-id)-deficient RPE indicated that this pathway for degradation is important normal function. However, affected deficient alpha-L-id activity or subsequent GAGs. Therefore, lysosomal prerequisite maintaining within limits.