PATHOBIOLOGY OF FIBRONECTIN IN DIABETES MELLITUS

纤维连接蛋白是一种存在于血浆、细胞中的大分子糖蛋白。 基质、基底膜和基底膜。主要并发症： 糖尿病(DM)是一种微血管异常和一种肾病 与肾小球基底膜(GBM)的发育相平行 形态计量学检测肾小球系膜体积增厚、增大。一位少校 系膜基质和基底膜的成分是纤维连接蛋白(FN)，并研究 已显示糖尿病患者肾小球系膜纤维连接蛋白含量增加。 研究将量化血清纤维连接蛋白水平，非酶水平 血浆纤维连接蛋白的糖基化、血糖水平和 肾组织中FN的非酶糖基化。形态计量分析 肾小球系膜体积和基底膜厚度与纤维连接蛋白相关 非酶糖基化。纤维连接蛋白存在于血管内皮细胞的 糖尿病肾脏的明显病理，并与其他各种疾病相互作用 基底膜或细胞基质的成分，如蛋白多糖和 胶原蛋白。接下来，我们将定义是否存在任何 FN在糖尿病中的分子相互作用。FN的许多相互作用 与其他配体的相互作用可能与电荷相互作用有关 受过度的非酶葡萄糖化作用影响。这种非酶 糖基化也会发生在与酶不同的位置。 糖基化作用发生在FN分子上的限制性区域。 将使用单抗和其他配体来分离FN多肽 其将以2-D凝胶为特征，并用于与 肝素、胶原等，过度非酶糖基化后。下一个 研究将确定糖尿病肾脏中FN过剩的原因。 研究将检查正态和正态分布的成交量和分布 糖尿病和非糖尿病动物的非酶糖基化FN。 放射性标记的或人的FN，正常或非酶糖基化， 会在不同的时间通过酶联免疫吸附试验进行计数或检测 物种特异性的单抗。接下来，我们将学习合成 肾小球培养中纤维连接蛋白的转化率、周转和积聚 由糖尿病和非糖尿病动物建立。这将是非常 如果对血浆成分的评估是有成效的，纤维连接蛋白可能会给我们 对微血管和肾脏病理的直接监测 对胰岛素依赖型糖尿病影响深远。

Fibronectin is a high molecular weight glycoprotein present in plasma, cell matrices, basement membranes, and basal lamina. Major complications of diabetes mellitus (DM) are microvascular abnormalities and a nephropathy which parallels the development of glomerular basement membrane (GBM) thickening and enlarged mesangial volume detected by morphometry. A major component of the mesangial matrix and GBM is fibronectin (FN), and studies have shown increased amounts of fibronectin in the mesangium in diabetes. Studies will quantitate serum levels of fibronectin, level of nonenzymatic glycosylation of plasma fibronectin, plasma glucose levels, and non-enzymatic glycosylation of FN in renal tissue. Morphometric analysis of mesangial volume and GMB thickness will be correlated with fibronectin non-enzymatic glycosylation. Fibronectin is present at sites of the apparent pathology of the diabetic kidney and interacts with various other constitutents of the GBM or cell matrix such as proteoglycans and collagen. We next will define whether there are perturbations of any molecular interactions of FN in diabetes. Many of the interactions of FN with other ligands may be related to charge interactions which could be effected by excessive nonenzymatic glucosylation. This nonenzymatic glucosylation would also be at sites other than those seen with enzymatic glycosylation which occurs at restricted domains on the FN molecule. Monoclonal antibodies and other ligands will be used to isolate FN peptides which will be characterized by 2-D gels and for affinity of binding to heparin, collagen, etc., after excess nonenzymatic glycosylation. The next studies would determine why there is excess FN in diabetic kidneys. Studies will examine turnover and distribution of normal and non-enzymatically glycosylated FN in diabetic and nondiabetic animals. Radiolabelled or human FN, both normal or non-enzymatically glycosylated, will be transfused and counted or assayed at varying times by ELISA with species specific monoclonal antibodies. Next we will study the synthetic rate, turnover, and accumulation of fibronectin in glomerular cultures established from diabetic and non-diabetic animals. It will be very fruitful if an evaluation of a plasma constituent, fibronectin may give us a direct monitor of the microvascular and renal pathology which are so profound in insulin dependent diabetes mellitus.