PROTEOGLYCANS IN DIABETIC NEPHROPATHY

在病程中，大约45%的IDDM患者 表现出某种程度的肾功能障碍，有些还会继续 随着时间的推移，肾功能衰竭的进展，组织病理学证明 肾小球硬化。期间发生的组织架构变化 进展为肾小球硬化。组织建筑 在进展为肾小球硬化的过程中发生的变化 包括肾小球肥大、肾小球 毛细血管基底膜(GBM)增厚，系膜扩张。 这些变化被认为在一定程度上是由生产过剩造成的。 属于和/或存在生物合成缺陷的分子 为基底膜和系膜的细胞外基质作出贡献。 虽然糖蛋白和糖蛋白的相对量增加 胶原蛋白成分在文献中已有报道，其中一些 IDDM最深刻的影响是对蛋白多糖成分的影响 各自的细胞外基质。 已知有两个不同的基底膜蛋白多糖群体 存在：硫酸乙酰肝素(BM-HSPG)和硫酸软骨素(BM-HSPG)和 硫酸软骨素(BM-CSPG)蛋白多糖。IDDM动物模型的实验研究 已有研究表明，BM的重要翻译后修饰- HSPG被改变，即合成一种未充分硫化的形式，在 转而影响分子功能。首席调查员现在展示了 发现了通常专属于系膜矩阵的BM-CSPG 糖尿病动物的基底膜异常。正在进行的研究，由 首席研究员认为，BM-CSPG在体内的沉积 基底膜内皮下区域导致正常 毛细血管组织构筑与最终闭塞 毛细血管。结果强烈表明，BM的生产过剩- CSPG可能是硬化性病变的直接因素。 糖尿病肾病的晚期。因为这些发现，现在 了解BM-CSPG的功能和调控变得非常重要 在分子水平上。 这项建议的具体目的是启动研究，以了解 BM-CSPG的细胞分子生物学及其与疾病进展的关系 糖尿病肾小球硬化。该项目将解决这一具体问题 目的通过以下一系列的研究。1.测定氨基酸 BM-CSPG核心蛋白的氨基酸序列分析 2.Northern检测糖尿病对BM-CSPG基因表达的影响 斑点杂交和原位杂交。预计拟议的 研究将部分回答这些问题，同时允许 为未来的研究开发必要的工具，这些研究将检查 从基因水平调控BM-CSPG基因转录。

During the course of their disease approximately 45% of IDDM patients manifest some degree of renal dysfunction and some will continue to progress over time toward renal failure, evidenced histopathologically as glomerulosclerosis. The histoarchitectural changes that occur during the progression toward glomerulosclerosis. The histoarchitectural changes that occur during the progression toward glomerulosclerosis have been well described and include glomerular hypertrophy, glomerular capillary basement membrane (GBM) thickening, and mesangial expansion. These changes are thought to be mediated in part by the overproduction of and/or the presence of biosynthetic defects in the molecules that contribute to the extracellular matrices of the GBM and mesangium. Although increases in the relative amounts of glycoprotein and collagenous components have been reported in the literature, some of the most profound effects of IDDM are on the proteoglycan component of the respective extracellular matrices. Two distinct basement membrane proteoglycan populations are known to exist: heparan sulfate (BM-HSPG) and chondroitin sulfate (BM-HSPG) and chondroitin sulfate (BM-CSPG) proteoglycans. In animal models of IDDM it has been shown that important posttranslational modifications to BM- HSPG's are altered, i.e. the synthesis of an undersulfated form that in turn affects molecular function. The principal investigator now shows that BM-CSPG, normally exclusive to the mesangial matrix, is found abnormally in the GBM of diabetic animals. Ongoing studies by the principal investigator suggest that the deposition of BM-CSPG in the subendothelial region of the GBM leads to disruption of the normal capillary histoarchitecture and eventual occlusion of affected capillaries. The results strongly suggest that the overproduction of BM- CSPG may be directly contributory to the sclerotic lesions seen in the latter stages of diabetic nephropathy. Because of these findings it now becomes important to understand the function and regulation of BM-CSPG at the molecular level. The specific aim of the proposal is initiate studies to understand the cell and molecular biology of BM-CSPG as it relates to the progression of diabetic glomerulosclerosis. The project will address this specific aim through the following series of studies. 1. To determine the amino acid sequence of the core protein of BM-CSPG by cDNA sequence analysis 2. determine the effects of diabetes on BM-CSPG mRNA levels by northern blotting and in-situ hybridization. It is anticipated that the proposed studies will in part answer these questions and, at the same time, allow development the tools necessary for future studies which will examine the regulation of BM-CSPG mRNA transcription at the gene level.