PROTEOGLYCANS IN DIABETIC NEPHROPATHY

在他们的疾病过程中，大约45%的IDDM患者 表现出一定程度的肾功能不全，有些将继续 随时间进展为肾衰竭，组织病理学证实 肾小球硬化症 发生的历史建筑变化 肾小球硬化症的进展 历史建筑 肾小球硬化进展过程中发生的变化 已被充分描述，包括肾小球肥大，肾小球 毛细血管基底膜（GBM）增厚，系膜扩张。 这些变化被认为部分是由生产过剩引起的。 和/或分子中存在生物合成缺陷， 有助于GBM和系膜的细胞外基质。 尽管糖蛋白和蛋白质的相对量增加， 在文献中已经报道了胶原成分， 胰岛素依赖型糖尿病最深刻的影响是对胰岛素依赖型糖尿病的蛋白多糖成分的影响。 各自的细胞外基质 已知两种不同的基底膜蛋白聚糖群体 存在：硫酸乙酰肝素（BM-HSPG）和硫酸软骨素（BM-HSPG）， 硫酸软骨素（BM-CSPG）蛋白聚糖。 在胰岛素依赖型糖尿病动物模型中 已经表明，BM-1的重要翻译后修饰， HSPG被改变，即合成一种硫酸化程度较低的形式， 反过来影响分子功能。 首席研究员现在表明 发现BM-CSPG，通常仅限于系膜基质， 在糖尿病动物的GBM中异常。 正在进行的研究 主要研究者认为，BM-CSPG在 GBM的内皮下区域导致正常的 毛细血管组织结构和最终闭塞的影响 毛细血管。 结果强烈表明，BM的过度生产- CSPG可能直接促成了 糖尿病肾病的早期症状 由于这些发现， 因此，了解BM-CSPG的功能和调节变得非常重要 在分子水平上。 该提案的具体目的是开展研究， BM-CSPG的细胞和分子生物学， 糖尿病性肾小球硬化症 该项目将解决这一具体问题， 通过以下一系列的研究。 1. 为了确定氨基 BM-CSPG核心蛋白cDNA序列分析 2.通过北方免疫组化检测糖尿病对BM-CSPG mRNA水平的影响， 印迹和原位杂交。 预计拟议的 研究将部分回答这些问题，同时， 为今后的研究开发必要的工具， 在基因水平上调控BM-CSPG mRNA的转录。

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.