Alternative Mechanisms of Monocyte Transendothelial Migration in Inflammation

项目摘要 炎症在身体中起到保护作用，以对抗感染和调节伤口愈合； 然而，如果不加以控制或不加以解决，炎症反应可能会变得有害。最病态的， 包括动脉粥样硬化、血管炎和缺血/再灌注损伤--这可能会加剧 心肌梗死和中风等并存疾病是由功能失调的炎症引起的。瞄准 因此，炎症可以提供抗击炎症性疾病的手段。这一目标可以通过以下方式实现 针对所有炎症背后的一个共同过程：白细胞的定向运动 (WBC)从循环进入受影响的组织。在这个过程中，经内皮细胞迁移(TEM)，WBC迁移 在内皮细胞(ECs)的侧缘之间，衬里血管进入炎症部位。TEM是一种 这是炎症反应中的关键一步，因为它是白细胞进入炎症组织之前的最终步骤。 成功阻断透射电子显微镜将防止炎症环境中的组织损伤，因此是一种 治疗目标。 TEM是通过白细胞和内皮细胞上的表面黏附分子之间的相互作用而介导的，结果 在传输来自EC侧边界回收隔间(LBRC)的膜的EC内的信令中， 血管周围的囊状小管结构，至透射电子显微镜的位置。这提供了所需的额外表面积 相邻EC之间的WBC迁移。LBRC的贩运是瞬变电磁的最终共同途径，无论 白细胞类型或炎性刺激。阻断关键黏附分子或下游EC信号 在体外和体内，通路阻断WBC的透射电子显微镜可达80-90%。然而，剩余的轮回率仍然存在 10-20%，提出了白细胞的特定亚群(S)是否对TEM封锁具有抵抗力的问题 以及未被阻断的WBC是否使用替代信号通路来招募LBRC进行轮回。 目的我将对克服透射电子显微镜阻断的单核细胞进行表型鉴定，以确定它们是否 代表不同的单核细胞亚群。我将询问这些细胞在一种 体外透射电子显微镜模型和小鼠炎症模型。这将允许识别表面 受体/信号通路可以靶向阻止所有循环中的单核细胞从 在100%阻断炎症的情况下的血管系统是至关重要的。AIM II将审问机制 允许这些单核细胞使用替代的轮回途径。我会利用一种有指导的体外筛查 用活体实时共聚焦显微镜检查来验证我的体外结果 在瞬变电磁法步骤中直接起作用的机制。该项目将阐明可供选择的瞬变电磁路径 在某些病理条件下可能很重要，并提醒我们身体可以通过哪些方式进行补偿 对于传统的瞬变电磁通道的长期封锁。

Project Summary Inflammation serves a protective role in the body to fight infection and mediate wound healing; however, the inflammatory response can become deleterious if left uncontrolled or unresolved. Most pathology, including atherosclerosis, vasculitis, and ischemia/reperfusion injury—which can exacerbate potential comorbidities such as myocardial infarcts and stroke—is due to dysfunctional inflammation. Targeting inflammation could thus provide the means to combat inflammatory disease. This objective can be realized by targeting a common process that underlies all inflammation: the directed movement of white blood cells (WBCs) from circulation into affected tissue. In this process, transendothelial migration (TEM), WBCs migrate between lateral borders of endothelial cells (ECs) lining blood vessels to enter sites of inflammation. TEM is a critical step in the inflammatory response as it is the ultimate step preceding WBC access to inflamed tissue. Successful blocking of TEM would preclude tissue damage in an inflammatory context and is thus a therapeutic goal. TEM is mediated by interactions between surface adhesion molecules on the WBC and ECs, resulting in signaling within ECs that traffics membrane from the EC lateral border recycling compartment (LBRC), a perivascular vesiculotubular structure, to the site of TEM. This provides additional surface area required for WBC migration between adjacent ECs. Trafficking of LBRC is the final common pathway for TEM regardless of WBC type or inflammatory stimulus. Blocking critical adhesion molecules or downstream EC signaling pathways blocks TEM of WBC by 80-90% in vitro and in vivo. However, residual transmigration rate remains 10-20%, raising the question as to whether specific subpopulation(s) of WBC are resistant to TEM blockade and whether non-blocked WBCs use alternative signaling pathways to recruit the LBRC to transmigrate. AIM I will phenotypically characterize monocytes that overcome TEM blockade to determine if they represent a distinct monocyte subset. I will interrogate the mechanism by which these cells transmigrate in an in vitro TEM model and in murine models of inflammation. This will allow for the identification of surface receptors/signaling pathways that can be targeted to block the exit of all circulating monocytes from the vasculature in situations in which blocking 100% of inflammation is critical. AIM II will interrogate mechanisms that allow these monocytes to use alternative transmigration pathways. I will utilize a guided in vitro screening approach and in vivo real time intravital confocal microscopy to validate my in vitro results by inspecting mechanisms functioning at the TEM step directly. The project will shed light on alternative TEM pathways that may be important under some pathologic conditions and alert us to ways in which the body may compensate for the chronic blockade of traditional TEM pathways.