GLOMERULAR LAMININS--STRUCTURE AND FUNCTION

肾小球层粘连蛋白——结构和功能

• 批准号: 2701177
• 负责人: CHRISTINE KREGER ABRASS
• 金额: $ 14.12万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-05-01 至 2000-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2701177
• 关键词: age difference; aging; angiotensin II; diabetic nephropathy; gene expression; glomerulonephritis; glycoprotein biosynthesis; hormone regulation /control mechanism; immunologic assay /test; insulin; kidney cell; laboratory rabbit; laboratory rat; laminin; mesangium; molecular cloning; neurotrophic factors; nucleic acid probes; protein isoforms; protein sequence; protein structure function; renal glomerulus; tissue /cell culture; wound healing

Cell-matrix interactions are critically important to cellular adhesion, proliferation, differentiation and regulation of matrix synthesis. Specificity of these interactions is determined by the subset of extracellular matrix (ECM) proteins expressed in a particular compartment and the subset of ECM protein receptors expressed by individual cells. Family members of collagen IV and laminin (LM) that are present within glomeruli are relatively unique and have limited distribution in other renal and non-renal ECMs. In renal diseases associated with glomerulosclerosis, the sclerotic lesions contain ECM proteins normally present as well as newly expressed ones. In preliminary studies of diabetic nephropathy and mesangial cells (MC) in culture, we have shown-that the mesangium contains unique isoforms of LM and that insulin and angiotensin II regulate their synthesis and accumulation. Based on these data, we hypothesize that normal MC secrete two classes of LM heterotrimers, a class that contains B2 and entactin and influences ECM assembly. A second class contains unique MC LMs that lack entactin, are concentrated on the cell surface and have unique functions within the glomerulus. Insulin and angiotensin II regulate the rate of synthesis of individual LM chains. In disease states where levels of these hormones are elevated for significant periods of time, their effects lead to progressive increases in LM isoforms normally present in low abundance. These changes lead to alterations in the structure and function of the mesangium, alter feedback regulation of ECM synthesis and ultimately contribute to loss of renal function. These hypotheses will be examined by the following specific aims: 1. Two new LM chains unique to the MC will be cloned, sequenced, and the heterotrimeric composition of MC LMs determined. 2. The mechanisms of insulin and angiotensin II-mediated changes in synthes of individual LM chains will be determined. Feedback regulation by B1 monom and its control by insulin and angiotensin II will be defined. 3. The function of unique MC LMs will be assessed by their ability to induc phenotypic changes and gene activation. The relationship to glomerular innervation, tile neurotrophins, and wound healing/scarring will be examine 4. The relevance of insulin and angiotensin II-mediated alterations in LM isoform expression to the development of glomerulosclerosis in diabetes and aging will be examined using in vivo models of these diseases. These studies will contribute basic information on structure and function o unique glomerular LMs and establish the role of insulin and angiotensin II regulation of LM synthesis and accumulation in glomerular disease.

细胞-基质相互作用对细胞至关重要 基质的黏附、增殖、分化与调控 综合。这些交互作用的特异性由 表达的细胞外基质(ECM)蛋白亚群 特殊的隔室和细胞外基质蛋白受体亚群 由单个细胞表达。IV型胶原和胶原蛋白家族成员 存在于肾小球内的层粘连蛋白(LM)相对 独特，在其他肾脏和非肾脏中的分布有限 ECM。在与肾小球硬化相关的肾脏疾病中， 硬化性病变包含正常存在的ECM蛋白以及 新表达的基因。在糖尿病的初步研究中 培养中的肾病和系膜细胞(MC)，我们已经证明- 系膜含有独特的LM和胰岛素亚型， 血管紧张素II调节它们的合成和积累。基于 根据这些数据，我们假设正常MC分泌两类LM 杂三聚体，一类含有B2和entactin及其影响的化合物 ECM组件。第二个类包含唯一的MC LMS，它缺少 Entactin，集中在细胞表面，具有独特的 肾小球内的功能。胰岛素与血管紧张素II 调节单个LM链的合成速度。在疾病中 这些荷尔蒙水平升高的州 在一段时间内，它们的影响会导致Lm逐渐增加 异构体通常以低丰度存在。这些变化导致 系膜结构和功能的改变 ECM合成的反馈调节，并最终有助于 肾功能丧失。 这些假设将通过以下具体目标进行检验： 1.将克隆MC独有的两条新的Lm链，对其进行测序，并 测定了MC LMS的异三聚体组成。 2.胰岛素和血管紧张素II介导的合成症变化机制 将确定单个LM链的数量。B1单体的反馈调节 它受胰岛素和血管紧张素II的控制将被定义。 3.独特的MC LMS的功能将通过它们的诱导能力进行评估 表型变化和基因激活。与肾小球的关系 本课程将检查神经支配、神经营养因子和伤口愈合/疤痕形成。 4.胰岛素与血管紧张素II介导的LM改变的相关性 异构体表达与糖尿病肾小球硬化发生发展的关系 衰老将使用这些疾病的体内模型进行检查。 这些研究将为进一步了解其结构和功能提供基础信息。 独特的肾小球LMS及其与胰岛素和血管紧张素II的关系 肾小球疾病中LM合成和蓄积的调节。