Altered glycoconjugates in cultures of retinitis pigmentosa retinal pigment epithelium.

These studies have shown that these are some alterations in the complex carbohydrates associated with the cell surface of RPE cells from donors with dominant retinitis pigmentosa. Differences are found both in proteoglycans and in glycoproteins. Proteoglycans of different sizes and glycosaminoglycan composition are associated with distinct cellular compartments of normal RPE cells. In the case of dominant retinitis pigmentosa studied here, there are some alterations in RPE proteoglycans. Within a given cellular compartment, there may be differences in the size distribution and/or the ratios of the proteoglycan size classes. In addition, there may be altered glycosaminoglycan content found between peaks of comparable size. There also appears to be more microheterogenity in oligosaccharides derived from surface glycoproteins of retinitis pigmentosa RPE cells. This may be due to differences in the total number of carbohydrate units or in the organization of the branching structure as suggested by altered size distribution and lectin-reactivity, respectively. While the reason for these differences is not clear, they could be due to abnormal processing and/or increased degradation. Considering their importance, alterations in cell surface glycoconjugates could affect the ability of RPE cells to interact with their environment and to maintain a healthy status.