PATHOBIOLOGY OF FIBRONECTIN IN DIABETES MELLITUS

纤连蛋白是一种高分子量糖蛋白，存在于血浆、细胞、 基质、基底膜和基底层。 主要并发症 糖尿病（DM）是微血管异常和肾病 其与肾小球基底膜（GBM）的发育平行 形态计量学检测系膜增厚和系膜体积增大。 一个主要 肾小球系膜基质和GBM的成分是纤维连接蛋白（FN）， 显示糖尿病患者系膜中纤维连接蛋白的量增加。 研究将定量测定血清纤连蛋白水平、非酶水平和血清中的蛋白水平。 血浆纤连蛋白的糖基化，血糖水平，和 肾组织中FN的非酶糖基化。 形态测定分析 肾小球系膜体积和GMB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 糖尿病肾病的明显病理，并与各种其他 GBM或细胞基质的组成成分，如蛋白聚糖和 胶原 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， 受过度非酶葡糖基化的影响。 这种非酶促的 葡萄糖基化也将在酶促反应所见的位点以外的位点发生。 糖基化，其发生在FN分子上的限制性结构域。 将使用单克隆抗体和其他配体来分离FN肽 其将通过2-D凝胶表征，并用于结合 肝素、胶原等，在过量的非酶糖基化之后。 下一 研究将确定为什么糖尿病肾脏中有过量的FN。 研究将审查正常和不正常的人员流动和分配情况， 糖尿病和非糖尿病动物中的非酶糖基化FN。 放射性标记或人FN，正常或非酶促糖基化， 将在不同时间进行输血和计数或通过ELISA进行测定， 种特异性单克隆抗体。 接下来我们将研究合成 肾小球培养物中纤连蛋白的速率、转换和积累 从糖尿病和非糖尿病动物建立。 这将是非常 如果对血浆成分进行评价，纤维连接蛋白可能会给我们带来成果， 直接监测微血管和肾脏病理， 胰岛素依赖型糖尿病的发病机制

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.