The influence of the protease inhibitor cystatin C on the occurrence of age-related macular degeneratin: evaluation of secretion by RPE cells and of possible mechanisms for its inhibition

我们以前已经表明，CST 3与渗出性年龄相关性黄斑变性（ARMD）有遗传相关性。在这项研究中，我们打算在视网膜色素上皮（RPE）细胞中的CST 3基因型和基因表达水平，以及CST 3基因产物，半胱氨酸蛋白酶抑制剂cystatin C的翻译后加工之间的相关性。胱抑素C是组织蛋白酶S的strog抑制剂，组织蛋白酶S是RPE细胞中最重要的蛋白酶之一;它参与这些细胞的蛋白水解代谢途径。基因型在细胞水平上影响表型的确切方式尚不清楚。本研究旨在确定半胱氨酸蛋白酶抑制剂C对蛋白酶的可能影响，包括在RPE细胞中具有高活性的组织蛋白酶S。通过使用RPE组织培养模型，我们将测试等位基因变体与晚期渗出性ARMD的可能关联，从而解决所产生的表型的分子基础。为了实现这些目标，我们建立了167例晚期渗出性ARMD患者和268例对照者的DNA库。此外，本实验室还建立了培养RPE细胞的方法。

We have previously shown that CST3 is genetically associated with exudative age-related macular degeneration (ARMD). In this study, we intend to correlate between the CST3 genotype and the levels of gene expression, as well as posttranslational processing of the CST3 gene product, the cysteine protease inhibitor cystatin C in retinal pigment epithelial (RPE) cells. Cystatin C is a strog inhibitor of cathepsin S, one of the most important proteases in RPE cells; it is involved in the proteolytic metabolic pathways of these cells. The exact ways by which genotype can influence the phenotype at the cellular level are unknown. This study was designed to determine possible influences of cystatin C on proteases including cathepsin S which has a high activity in RPE cells. By using the RPE tissue culture model, we will test possible associations of the allelic variants with advanced exudative ARMD, and thus address the molecular basis of the resulting phenotype. To pursue these objectives, we habe established a DNA bank derived from of l67 patients with advanced exudative ARMD and from 268 control subjects. Moreover, the methods of culturing RPE cells are established in our laboratory.