Regulation of Protein C Pathways

活化蛋白C(APC)是一种天然存在的血浆丝氨酸蛋白酶，已被翻译到临床上 作为重组野生型或突变型生物。在一系列临床前动物损伤模型中， 药理上的APC提供好处。APC不仅具有抗凝血活性，还能启动细胞信号转导 通过多个受体，特别是通过几个蛋白酶激活的受体(PAR)。APC启动的细胞信令 有助于组织动态平衡和宿主防御系统。导致有益的APC发起的偏向信令 通过PAR1和PAR3的特异性切割，也可以通过APC与内皮细胞上的Tie2结合而触发 细胞。尽管有最近的见解，但关于蛋白质-蛋白质相互作用(PPI)的知识存在着重大差距 APC及其细胞受体。AIM 1研究将使用28个重组APC突变体的文库来提供 有关APC受体特异性的数据库，这将使APC突变体的工程具有 受体特异性选择性，例如，具有高度选择性PAR1或PAR3特异性信号的APC突变体 能力。这种受体选择性的APC突变体将成为破译哪些受体发挥作用的有用试剂 在体外或在动物体内对细胞的关键作用，它们可能导致新的APC突变体的翻译。一 APC的主要抗炎机制是最近发现的抑制NLRP3炎症小体的能力 激活。有一个主要的需要了解APC如何抑制炎症体的激活，以及Aim 2研究 将提供高度新奇的新知识。当相对于凝血酶生成产生过量的APC时， 出血的风险增加。这可能发生在血友病或直接口服期间。 抗凝剂(DOAC)。目的3研究将提供关于小鼠出血和关节损伤的新知识 血友病模型与相对过多的APC有关，并将确定各种策略是否可能减少 由于血友病关节出血而引起的关节损伤。拟议的研究将提供新的机制 洞察和新的APC变体，可能有助于与APC途径相关的翻译。

Activated protein C (APC) is a naturally occurring plasma serine protease that has been translated to the clinic as a recombinant wild type or mutant biologic. In a diverse collection of preclinical animal injury models, pharmacologic APC provides benefits. APC not only has anticoagulant activity but also initiates cell signaling via multiple receptors, in particular via several protease activated receptors (PAR). APC-initiated cell signaling contributes to tissue homeostasis and host defense systems. Beneficial APC-initiated biased signaling is caused by specific cleavages of PAR1 and PAR3, and it also can be triggered by APC binding to Tie2 on endothelial cells. Despite recent insights, there is a major gap in knowledge about protein-protein interactions (PPI) between APC and its cellular receptors. Aim 1 studies will use a library of 28 recombinant APC mutants to provide a database regarding APC's receptor specificities which will then enable engineering of APC mutants with receptor-specific selectivity, e.g., an APC mutant with highly selective PAR1-specific or PAR3-specific signaling capabilities. Such receptor-selective APC mutants will be useful reagents for deciphering which receptors play critical roles on cells in vitro or in animals in vivo, and they may lead to translation for novel APC mutants. One major anti-inflammatory mechanism for APC is its recently discovered ability to inhibit NLRP3 inflammasome activation. There a major need for understanding how APC inhibits inflammasome activation, and Aim 2 studies will provide highly novel new knowledge. When APC is generated in excess relative to thrombin generation, increased risk for bleeding arises. This may potentially occur in hemophilia or during use of direct oral anticoagulant (DOAC). Aim 3 studies will provide new knowledge about bleeding and joint damage in murine hemophilia models linked to relatively excessive APC and will determine whether various strategies may reduce joint damage that arises due to bleeding in hemophilic joints. The proposed studies will provide novel mechanistic insights and new APC variants which may aid translation related to the APC pathways.