Novel Thrombotic and Inflammatory Activities of Platelets in Sepsis

脓毒症是一种对感染的适应不良反应，是一种常见且致命的综合征。许多研究 已经检查了脓毒症或替代模型中白细胞和内皮细胞的活性， 但血小板在疾病过程中的作用却很少受到关注。这种缺乏 洞察力既令人惊讶，又可能具有局限性，因为有大量证据表明， 血小板被激活，并在大多数情况下， 不是所有的败血症患者。我们已经确定了新的血小板反应，可能有助于败血症。 在这方面，我们发现巨核细胞将功能性剪接体转移到人类， 血小板和活化的血小板剪接组成性表达的前体mRNA进入成熟的 成绩单在初步数据中，我们发现从脓毒症患者中分离的血小板表达 组织因子的剪接mRNA，因此具有增加的促凝血活性。这里我们 在这些初步发现的基础上，启动一系列临床前筛查， 脓毒症环境中存在的激动剂激活人血小板的剪接体， 抑制试剂阻断前mRNA剪接并减少脓毒症相关炎症。为了 为了在两年内完成我们的研究，我们缩小了具体目标1的范围， 目标2中的研究。具体而言，修订后的目标1将描述前mRNA剪接事件， 脓毒症患者血培养阳性血小板剪接体的活化 菌血症来自这些脓毒症患者的血浆和细菌将用于进行以下研究： 第二个目标是确定控制人类前体mRNA剪接事件的机制， 血小板暴露于脓毒症的情况下。目的2还检查了试剂的抑制特性 在纯化的血小板制剂和全血模型系统中阻断前mRNA剪接， 败血症总之，这些研究将产生新的见解的分子病理生物学， 脓毒症，并可能提供新的治疗干预的目标。

Sepsis, a maladaptive response to infection, is a common and lethal syndrome. Many studies have examined the activities of leukocytes and endothelial cells in sepsis or in surrogate models, but the role of platelets in the disease process has received far less attention. This paucity of insight is both surprising and potentially limiting, because there is abundant evidence that platelets are activated and contribute to the vascular and inflammatory manifestations in most, if not all, septic patients. We have identified novel platelet responses that may contribute to sepsis. In this regard, we found that megakaryocytes transfer a functional spliceosome to human platelets and that activated platelets splice constitutively expressed pre-mRNAs into mature transcripts. In preliminary data, we show that platelets isolated from septic patients express spliced mRNA for tissue factor and, as a result, have increased procoagulant activity. Here, we build on these preliminary findings by initiating a set of pre-clinical screens to determine if key agonists present in the septic milieu activate the spliceosome of human platelets and whether inhibitory reagents block pre-mRNA splicing and reduce sepsis associated inflammation. In order to complete our studies within two years, we narrow the scope of specific aim 1 and accelerate studies in aim 2. Specifically, revised aim 1 will characterize pre-mRNA splicing events and activation of the spliceosome in platelets isolated from septic patients with blood culture positive bacteremia. Plasma and bacteria from these sepsis patients will be used to perform studies in the second aim, which defines the mechanisms that control pre-mRNA splicing events in human platelets exposed to septic situations. Aim 2 also examines the inhibitory properties of reagents that block pre-mRNA splicing in purified platelet preparations and whole blood model systems of sepsis. Together, these studies will generate new insights into the molecular pathobiology of sepsis and may provide new targets for therapeutic intervention.