ADHESION PROTEINS AND CYTOKINES IN GLOMERULONEPHRITIS

大多数类型的人类和实验性肾小球肾炎是 以白细胞(中性粒细胞)为特征。单核/巨噬细胞) 随着氧化剂等炎症介质的释放而渗入 这些细胞中的蛋白水解酶负责肾小球的大部分 受伤。这些白细胞从外周血中招募的机制 肾小球的循环和定位是未知的，也是 这项研究提案。我们假设白细胞的粘附性 分子(整合素)及其相应的配体表达于 常驻肾小球细胞(内皮细胞和系膜细胞)不是必需的 不仅用于白细胞在肾小球中的定位，也用于白细胞的定位 介导对肾小球细胞的损伤。建议进行的研究 要解决这一假设，本质上是双重的。我们将使用 经典抗肾小球基底膜肾炎模型大鼠的作用观察 体内的黏附分子。该模型具有一个很好的特点： 中性粒细胞依赖的异种期和后来的巨噬细胞依赖 自体阶段。在这两个阶段中，我们将期待 ELAM-1、VCAM-1和ICAM-1在肾小球中的表达及其与 白细胞渗入。我们将直接确定 这些黏附分子在这个模型中通过使用特定的单抗 抗ELAM-1、VCAM-1和ICAM-1的抗体以及白细胞 整合素CD18和CD11b与我们的初步研究显示 起到了保护作用。我们还将探索一种假设，即一种主要的 肿瘤坏死因子α和白介素1等细胞因子的生物学效应上调 这些黏附分子。为了解决这个问题，我们将确定是否 直接输注这些细胞因子可诱导黏附上调 肾小球中的分子，反之，如果特异性抗体 这些细胞因子通过预防肾小球损伤而抑制肾小球损伤。 这些分子的上调。在相关的体外研究中 将确定氧自由基等炎症介质和 细胞因子上调ELAM-1、VCAM-1和ICAM-1在系膜和肾小球上的表达 培养中的内皮细胞。此外，我们将确定是否 氧化剂上调中性粒细胞和单核细胞整合素的表达 白细胞整合素抗体、抗CD18和CD11b对血管内皮细胞生长的影响 白细胞依赖性对内皮细胞和系膜细胞的杀伤。我们的 初步研究表明系膜细胞表达黏附分子 与内皮细胞相似，这些黏附分子是 不仅对粘附性很重要，而且对白细胞介导的 细胞毒性。上文概述的拟议研究应提供新的 和有用的信息，关于黏附分子在 肾小球肾炎。如果事实上黏附分子被证明是 在该病发病机制中的重要作用 然后建议使用单抗进行特异性的“抗粘连”治疗； 抗体在治疗慢性阻塞性肺疾病中可能有有益的作用 肾小球肾炎。

Most types of human as well as experimental glomerulonephritis are characterized by leukocyte (neutrophil. monocyte/macrophage) infiltration with the release of inflammatory mediators such as oxidants and proteases from these cells responsible for much of the glomerular injury. The mechanism by which these leukocytes are recruited from the circulation and localize in the glomeruli is unknown and is the focus of this research proposal. We hypothesize that leukocyte adhesion molecules (integrins) and their corresponding ligands expressed on resident glomerular cells (endothelial and mesangial) are necessary not only for leukocyte localization in the glomerulus but also for leukocyte mediated injury to the resident glomerular cells. The proposed studies to address this hypothesis will be two-fold in nature. We will use the classic model of anti-GBM nephritis in the rat to look at the role of adhesion molecules in vivo. This model is well characterized with a neutrophil dependent heterologous phase and a later macrophage dependent autologous phase. In both phases we will look for the upregulation of ELAM-1, VCAM-1, and ICAM-1 in the glomeruli and how this correlates with leukocyte infiltration. We will determine directly the importance of these adhesion molecules in this model by using specific monoclonal antibodies to ELAM-1, VCAM-1, and ICAM-1 as well as the leukocyte integrins CD18 and CD11b with our preliminary studies showing a protective effect. We will also explore the hypothesis that a primary biologic effect of cytokines such as TNFalpha and IL-1 is upregulation of these adhesion molecules. To address this we will determine if direct infusion of these cytokines induces upregulation of adhesion molecules in glomeruli and also conversely if specific antibodies to these cytokines inhibits the glomerular injury by preventing the upregulation of these molecules. In correlative in vitro studies we will determine if inflammatory mediators such as oxygen radicals and cytokines upregulate ELAM-1, VCAM-1, and ICAM-1 on mesangial and endothelial cells in culture. In addition, we will determine if oxidants upregulate integrin expression on neutrophils and monocytes and the effect of the leukocyte integrin antibodies; anti-CD18 and CD11b on leukocyte dependent killing of endothelial and mesangial cells. Our preliminary studies show that mesangial cells express adhesion molecules similar to the endothelial cells and that these adhesion molecules are important not only for adherence but also for leukocyte mediated cytotoxicity. The proposed studies as outlined above should provide new and useful information on the role of adhesion molecules in glomerulonephritis. If in fact adhesion molecules turn out to be as important in the pathogenesis of this disease as our preliminary studies suggest then specific "anti-adhesion" therapy using monoclonal; antibodies could have a beneficial effect in the treatment of glomerulonephritis.