Kindlin-3 Signaling in Blood Cells

深静脉血栓形成(DVT)是世界范围内发病率和死亡率的主要原因之一。DVT是 与多种危险因素有关，当深静脉中形成血栓时就会发生。值得注意的是，最近 研究表明，中性粒细胞基本上参与了深静脉血栓的形成，表明深静脉血栓是一种 凝血级联反应和先天免疫系统复杂、协调的功能障碍。研究项目： 动物DVT模型已经证明，中性粒细胞最初的募集和随后的中性粒细胞的释放 细胞外陷阱(Net)促进血栓的生长；此外，后来的中性粒细胞渗透促进血栓的形成 提示中性粒细胞在DVT中可能起着双重功能作用。Kindlin-3是最近发现的一种 血细胞中整合素β胞浆尾部结合蛋白及支持整合素介导的白细胞所需 招募和渗透。Kindlin-3缺乏症患者患有III型白细胞黏附缺陷， 一种罕见的遗传性疾病，其特征是由于整合素功能障碍而反复感染和严重出血 包括白细胞和血小板。重要的是，我们的初步观察表明Kindlin-3还 在中性粒细胞中执行许多不依赖于整合素的功能，包括抑制净释放。 因此，我们推测kindlin-3在DVT的动力学调控中起着多重作用。总目标 这一竞争性应用的目的是研究整合素依赖和不依赖整合素的功能 Kindlin-3在DVT形成中性粒细胞中的表达，并从机制上解释Kindlin-3在DVT形成过程中的新功能 调节净释放。提出了两个具体目标：(1)具体目标1将决定 深静脉血栓形成中性粒细胞中Kindlin-3/整合素的相互作用。我们将研究深静脉血栓形成的动力学。 一种携带整合素相互作用干扰突变的标准下腔静脉结扎模型 在kindlin-3或kindlin-3缺失中，特别是在中性粒细胞中。中性粒细胞募集的动力学和程度， 这些小鼠的下腔静脉渗透、净释放、血栓生长和溶解将使用 活体显微镜和组织学分析的结合。我们期待kindlin-3发挥重要作用。 中性粒细胞在炎症的下腔静脉重新募集中的作用，在静脉血栓形成的地方和后来 中性粒细胞渗入形成的血栓，促进深静脉血栓的消退。(2)具体目标2将确定 中性粒细胞kindlin-3调节DVT净释放的分子机制。关键子域(S) 负责调节净释放的kindlin-3中的残基(S)将被映射到信息模型系统中。 Kindlin-3和净释放之间的信号中间产物将通过建立的生化方法进行鉴定 接近了。此外，Kindlin-3/Nets信号通路在DVT形成中的作用将在 老鼠。总而言之，这些研究将重新定义我们对复杂机制的理解 中性粒细胞kindlin-3调节DVT的动力学，从而为设计新的靶向提供了机会。 防治深静脉血栓的治疗策略。

Deep vein thrombosis (DVT) is one of the major causes of morbidity and mortality worldwide. DVT is associated with multiple risk factors and occurs when a blood clot forms in the deep veins. Significantly, recent studies have revealed that neutrophils are essentially involved in DVT formation, indicating that DVT is a complex, coordinated dysfunction of both the coagulation cascade and the innate immune system. Studies in animal DVT models have demonstrated that initial neutrophil recruitment and subsequent release of neutrophil extracellular traps (NETs) promote thrombus growth; in addition, later neutrophil infiltration facilitates thrombus resolution, suggesting that neutrophils may play dual functional roles in DVT. Kindlin-3 is a recently identified integrin β cytoplasmic tail binding protein in blood cells and required for supporting integrin-mediated leukocyte recruitment and infiltration. Patients with kindlin-3 deficiency suffer from Type-III leukocyte adhesion deficiency, a rare genetic disorder characterized by recurrent infections and severe bleeding due to integrin dysfunction in both leukocytes and platelets. Importantly, our preliminary observations have suggested that kindlin-3 also carries out a number of integrin-independent functions in neutrophils, including suppressing NET release. Therefore, we hypothesize that kindlin-3 plays multiple roles in regulating the kinetics of DVT. The overall goal of this competitive application is to examine both integrin-dependent and integrin-independent functions of kindlin-3 in neutrophils in DVT formation, and to mechanistically interpret the novel function of kindlin-3 that regulates NET release. Two Specific Aims are proposed: (1) Specific Aim 1 will determine the importance of kindlin-3/integrin interactions in neutrophils in DVT formation. We will examine the kinetics of DVT formation in a standard inferior vena cava (IVC) ligature model in mice that carry an integrin-interaction disrupting mutation in kindlin-3 or a kindlin-3 deletion specifically in neutrophils. The kinetics and extent of neutrophil recruitment, infiltration in the IVC, NET release, thrombus growth and resolution will be quantified in these mice using a combination of both intravital microscopy and histological analysis. We expect that kindlin-3 plays important roles in both initial neutrophil recruitment to inflamed IVC where venous thromboemboli develop and later neutrophil infiltration into the formed thrombi that promotes DVT resolution. (2) Specific Aim 2 will determine the molecular mechanism by which neutrophil kindlin-3 regulates NET release in DVT. The key subdomain(s) and residue(s) in kindlin-3 responsible for regulating NET release will be mapped in informative model systems. The signaling intermediates between kindlin-3 and NET release will be identified by established biochemical approaches. Further, the contribution of kindlin-3/NETs signaling pathway to DVT formation will be evaluated in mice. Taken together, these studies will redefine our understanding of the complex mechanisms by which neutrophil kindlin-3 regulates the kinetics of DVT, thus providing opportunities for designing novel and targeted therapeutic strategies for prevention and treatment of DVT.