Macrophage Infiltration of Renal Tissue via beta-3 Integrins and Agrin

描述（由申请人提供）：肾小球肾炎是最常见的自身免疫诱导的炎症事件，其中巨噬细胞浸润肾脏导致纤维化导致肾功能丧失。我们实验室的长期目标是确定控制巨噬细胞粘附的分子开关，从而调节炎症反应。我们以前确定了23整合素粘附受体的酪氨酸磷酸化作为一个这样的开关，并已证明，23磷酸化是必要的巨噬细胞粘附到一些配体。由于肌动蛋白细胞骨架不能组织成应力纤维，23磷酸化的阻断导致粘附的丧失。在本申请中，我们提出的证据表明，这种独特的机制是需要巨噬细胞进入肾组织。我们假设巨噬细胞通过肾基底膜是由蛋白聚糖聚集蛋白和磷酸化23整合素之间的相互作用介导的。在这个应用程序中，我们将评估的作用，23整合素及其磷酸化迁移到肾组织在实验性肾小球肾炎。我们将通过体外迁移研究确定肾基底膜聚集蛋白是否调节巨噬细胞浸润。我们将通过活体巨噬细胞的TIRF显微镜观察来表征巨噬细胞足体粘连和伪足的产生，这些伪足是迁移到三维组织中所必需的。我们将生化地确定来自磷酸化23的信号传导，磷酸化23控制巨噬细胞伪足和足体中肌动蛋白细胞骨架重组。在器官特异性巨噬细胞免疫运输过程中使用的机制的鉴定可以为治疗干预和补充全面免疫抑制疗法提供新的靶点。公共卫生相关性：r实验室已经确定了一种新的白色血细胞粘附于组织的机制。这项研究计划将确定一种在白色血细胞亚群上发现的称为23整合素的特殊粘附分子是否有助于肾小球肾炎（肾脏炎症）。了解肾小球肾炎的发病机制可以为药物提供新的靶点，以减少这种疾病的进展。

DESCRIPTION (provided by applicant): Glomerulonephritis is most commonly an autoimmune-induced inflammatory event wherein infiltration of the kidney by macrophages results in loss of renal function due to fibrosis. The long-term goal of our laboratory is to identify the molecular switches that govern macrophage adhesion and thus regulate the inflammatory response. We previously identified tyrosine phosphorylation of 23 integrin adhesion receptors as one such switch and have demonstrated that 23 phosphorylation is necessary for macrophage adhesion to some ligands. Blockade of 23 phosphorylation results in loss of adhesion due to a failure of the actin cytoskeleton to organize into stress fibers. In this application we present evidence that this unique mechanism is required for macrophage entry into renal tissues. We hypothesize that macrophage passage through renal basement membrane is mediated by an interaction between the proteoglycan agrin and phosphorylated 23 integrins. In this application we will assess the role of 23 integrins and their phosphorylation in migration to renal tissues during experimental glomerulonephritis. We will determine whether agrin in renal basement membrane regulates macrophage infiltration by in vitro transmigration studies. We will characterize the production of macrophage podosomal adhesions and pseudopods that are required for migration into three-dimensional tissues by TIRF microscopy of living macrophages. We will biochemically determine the signaling from phosphorylated 23 that controls actin cytoskeletal reorganization in the macrophage pseudopod and podosome. Identification of mechanisms used during organ-specific macrophage immune trafficking can provide novel targets for therapeutic intervention and complement global immune-suppressive therapies. PUBLIC HEALTH RELEVANCE: r laboratory has identified a new mechanism of white blood cell adhesion to tissues. This research proposal will determine whether a particular adhesion molecule called 23 integrin, found on a subset of white blood cells, contributes to glomerulonephritis (inflammation of the kidneys). Understanding the mechanism of glomerulonephritis can provide new targets for drugs to reduce the progression of this disease.