Beyond PECAM: Mechanisms of Transendothelial Migration

项目SuIVIMARY(请参阅说明)： 这项研究应用的长期目标是更好地理解细胞和分子基础 以开发更好的治疗方法来增强炎症反应 宿主的免疫反应受到损害，并在以下情况下抑制它 适得其反，如在动脉粥样硬化、类风湿性关节炎等炎症性疾病中 自身免疫性疾病、感染性休克、哮喘和移植排斥反应。炎症性疾病的关键一步 反应是白细胞从血液中迁移到炎症部位。我们一直在 研究负责渗出的分子和机制--这一过程中的步骤 在白细胞流出部位，白细胞穿过毛细血管后小静脉内皮细胞。在 在这笔赠款的第一个资助期，我们发现了一种分子(CD99)和一种机制(靶向回收 来自称为LBRC的内部交界间隔的膜)，在 渗出症。到目前为止，在第二个资助期(即荣誉奖的前3.5年)，我们有 已经完成了5年计划的大部分具体目标：我们调查了CD99是如何 调节发育期。我们发现它存在于LBRC中，其功能需要 隔间里也有聚乙二醇胺。我们已经克隆了CD99的小鼠版本和 相关分子CD99L2，并证明两者都在轮回中起作用。我们已经证明了 跨细胞迁移涉及与细胞旁迁移相同的机制：靶向膜 以微管依赖的方式从LBRC贩运到迁徙地点。的目标是 功绩延长期是为制定这些工作提出的具体目标，回答下一步 重要的问题。这些问题包括：CD99需要哪些信号才能完成轮回？ 为什么CD99的功能依赖于PECAM？(这些分子是如何相互作用的？)做CD99和CD99L2 在体内的功能互补吗？如果是这样的话，是如何做到的呢？阻断它们在慢性前列腺癌模型中的治疗作用 炎症性疾病？在体外和体内，LBRC膜是如何被招募进行跨细胞迁移的？

PROJECT SUIVIMARY (See instructions): The long-term objectives of this research application is to better understand the cellular and molecular basis of the inflammatory response in order to develop better therapies to augment it in conditions where the host's immune response is compromised, and to inhibit it under conditions where the response is counterproductive, such as in inflammatory diseases like atherosclerosis, rheumatoid arthritis and other autoimmune diseases, septic shock, asthma, and transplant rejection. A critical step in the inflammatory response is the migration of leukocytes out ofthe bloodstream to the site of inflammation. We have been studying the molecules and mechanisms responsible for diapedesis-the step in this process in which leukocytes pass across the endothelial cells lining postcapillary venules at sites of leukocyte egress. In the first funding period of this grant, we discovered a molecule (CD99) and a mechanism (targeted recycling of membrane from an intemal perijunctional compartment called the LBRC) that play significant roles in diapedesis. In the second funding period thus far (i.e., the first 3.5 years ofthe MERIT award) we have already accomplished most of the Specific Aims of the 5 year plane: We have investigated how CD99 regulates diapedesis. We have discovered that it is present in the LBRC and its function requires the presence of PECAM in the compartment as well. We have cloned the mouse version of CD99 and the related molecule CD99L2 and demonstrated that both play a role in transmigration. We have demonstrated that transcellular migration involves the same mechanism as paracellular migration: Targeted membrane trafficking from the LBRC to the site of migration in a microtubule-dependent manner. The goals for the MERIT extension period are to develop the work proposed for these specific aims to answer the next important questions. These include: What signals from CD99 are required to complete transmigration? Why does CD99 function depend on PECAM? (How do these molecules interact?) Do CD99 and CD99L2 complement each other's function in vivo? If so, how? Is blocking them therapeutic in models of chronic inflammatory disease? How is LBRC membrane recruited for transcellular migration in vitro and in vivo?