MESANGIAL CELL INTERACTIONS WITH GLUCOSYLATED MATRIX

系膜细胞与糖基化基质的相互作用

• 批准号: 3244936
• 负责人: PHOTINI C TSILIBARY
• 金额: $ 12.61万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-03-01 至 1995-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3244936
• 关键词: SDS polyacrylamide gel electrophoresis; animal tissue; autoradiography; basement membrane; beta aminopropionitrile; blood glucose; cell adhesion; cell cell interaction; cell cycle; cell growth regulation; circular dichroism; collagen; complementary DNA; cow; diabetes mellitus; diabetic nephropathy; electron microscopy; embryo /fetus cell /tissue; extracellular matrix; gene expression; genetic library; genetic transcription; glucose; glycosylation; high performance liquid chromatography; human genetic material tag; human tissue; ion exchange chromatography; kidney cell; lysine; mesangium; messenger RNA; methionine; microscopy; molecular pathology; neoplastic cell culture for noncancer research; northern blottings; nucleic acid hybridization; protein biosynthesis; protein purification; protein structure function; radiotracer; renal glomerulus; thin layer chromatography; thymidine; tritium; western blottings

Diabetic nephropathy with renal failure is a major complication of diabetes mellitus which occurs in 35 to 45% of diabetic patients. Characteristic lesions of diabetic glomerulopathy include thickening of the glomerular basement membrane and a progressive expansion of the mesangial matrix which surrounds the mesangial cells. A number of studies have correlated the expansion of the mesangium with loss of renal function, in part due to a restriction of the filtering area. An interesting observation is that following pancreatic transplantation, when glucose levels become normalized, the renal function is restored and the mesangial expansion recesses whereas GBM thickening persists. These findings indicate the utmost importance of the mesangial space in the development of diabetic glomerulopathy and provide evidence that the mesangial expansion is directly related to hyperglycemia. Because mesangial cells secrete at least several components of the mesangial matrix (MM), one of which is type IV collagen, we propose to study interactions between the mesangial matrix, type IV collagen (tIV) and mesangial cells under control conditions and following exposure to high glucose levels. A major modification of long- lived proteins (like matrix proteins, i.e., type IV collagen) which occurs in the presence of high glucose is the process of non-enzymatic glucosylation which alters the proteins structurally and functionally. It is known that type IV collagen extracted from kidneys of diabetic animals and patients is non-enzymatically glucosylated. Our goal therefore is to test whether non-enzymatic glucosylation of type IV collagen and MM relate to the expansion of MM by causing altered interactions with the mesangial cells. Three questions will be asked: first, whether the adhesion and spreading of mesangial cells is different when these cells interact with unmodified versus non-enzymatically glucosylated tIV and intact, isolated GBM which also contains the mesangial matrix (GBM/MM); second, whether the growth rate of mesangial cells changes in response to non-enzymatic glucosylation of tIV and GBM/MM, when compared to their unmodified counterparts; and third, whether the biosynthesis of the (a1) and (a2) chains of tIV based on mRNA levels is increased in response to diabetic modifications of tIV and GBM/MM, when compared to their unmodified counterparts. These studies will seek to address a fundamental question, whether the abnormal expansion of the mesangium may be in part causally related to altered interactions between mesangial cells and their surrounding matrix and in particular tIV, as a consequence of non-enzymatic glucosylation of tIV and the MM in general. Therefore, these studies will contribute to a better understanding of the causes of diabetic mesangial expansion at a molecular level and will lead to seek means which may subsequently be used to prevent or minimize the process of non-enzymatic glucosylation.

糖尿病肾病伴肾功能衰竭是糖尿病的主要并发症 35% 至 45% 的糖尿病患者会出现这种情况。 特征 糖尿病肾小球病的病变包括肾小球增厚 基底膜和系膜基质逐渐扩张 包围系膜细胞。 许多研究已经将 系膜扩张并伴有肾功能丧失，部分原因是 过滤面积的限制。 一个有趣的观察是 胰腺移植后，当血糖水平变得 正常化，肾功能恢复，系膜扩张 凹陷，而 GBM 增厚持续存在。 这些发现表明 系膜间隙在糖尿病的发生发展中至关重要 肾小球病并提供系膜扩张的证据 与高血糖有直接关系。 因为系膜细胞分泌 系膜基质（MM）的至少几个组成部分，其中之一是类型 IV 胶原蛋白，我们建议研究系膜基质之间的相互作用， IV型胶原蛋白（tIV）和系膜细胞在对照条件下和 暴露于高葡萄糖水平后。 长的一个重大修改 发生的活蛋白（如基质蛋白，即 IV 型胶原蛋白） 在高葡萄糖存在下是非酶促的过程 糖基化改变蛋白质的结构和功能。 它 众所周知，从糖尿病动物的肾脏中提取的 IV 型胶原蛋白 并且患者被非酶促糖基化。 因此我们的目标是 测试 IV 型胶原蛋白的非酶糖基化与 MM 是否相关 通过改变与系膜的相互作用来影响 MM 的扩张 细胞。 会问三个问题：第一，是否附着力 当这些细胞相互作用时，系膜细胞的扩散是不同的 未修饰的 tIV 与非酶促糖基化的 tIV 以及完整、分离的 GBM 还包含系膜基质 (GBM/MM)；第二，是否 系膜细胞的生长速率因非酶促反应而变化 与未修饰的相比，tIV 和 GBM/MM 的糖基化 同行；第三，(a1)和(a2)是否生物合成 基于 mRNA 水平的 tIV 链因糖尿病而增加 与未修改的相比​​，tIV 和 GBM/MM 的修改 同行。 这些研究将寻求解决一个基本问题， 系膜异常扩张是否可能是部分原因 与系膜细胞及其之间相互作用的改变有关 周围基质，特别是 tIV，作为非酶促的结果 tIV 和 MM 的一般糖基化。 因此，这些研究将 有助于更好地了解糖尿病系膜病的原因 在分子水平上进行扩展，并将导致寻找可能的方法 随后用于防止或最小化非酶促过程 糖基化。