Endothelial injury and repair following hemorrhagic shock

项目总结/摘要 创伤是第三大死亡原因。在这些死亡中，出血仍然是导致死亡的头号原因。 早期创伤死亡，尽管现代复苏策略已经降低了早期死亡率。 出血幸存者的早期死亡率进一步降低，多器官功能衰竭（MOF）发生率进一步降低 代表进一步改善出血性休克（HS）后护理的机会。我们的努力集中在扭转上 创伤和HS后的内皮功能障碍称为“创伤内皮病”（EoT）。我们 首次在患者中证实了syndecan-1（Sdc 1），一种细胞表面蛋白聚糖，在创伤后脱落 并且脱落与不良结局相关。然而，对Sdc 1表达的了解要少得多。 以及它对内皮细胞的影响，这代表了我们知识上的一个空白。在我们努力定义 对于Sdc 1下调，我们发现microRNA-19 b（miR-19 b）靶向Sdc 1，表型模仿了 HS在减少Sdc 1表达，并有助于EoT，新的观察。我们的数据还表明， miR-19 b可能是一个治疗靶点，因为miR-19 b逆转了Sdc 1下调的有害作用。 我们还将表明，纤维蛋白原，作为一个关键组成部分，在血浆中，并作为一个孤立的治疗，共定位 并与内皮细胞表面上的Sdc 1结合以增强Sdc 1表达，降低miR-19 b表达， 恢复屏障完整性。创伤后全身纤维蛋白原浓度降低与创伤后纤维蛋白原水平升高有关。 损伤的严重程度和死亡率的预测。尽管如此，在美国的标准做法是取代纤维蛋白原 （使用冷沉淀）只有一次水平下降，并在大量输血后期。本研究结果 将支持实践中的重大变化，包括早期使用纤维蛋白原作为内皮保护剂，以减轻 降低死亡率。 我们的初步数据支持新的假设，即miRNA-19 b诱导Sdc 1下调， HS导致内皮细胞屏障完整性的破坏。我们进一步假设纤维蛋白原恢复 通过抑制miR-19 b，与细胞表面的Sdc 1结合，并激活 PAK 1恢复屏障完整性并减轻肺损伤。我们将通过以下方式来检验我们的假设 目标：SA 1.确定miR-19 b在失血性休克后内皮细胞Sdc 1下调中的作用 以及miR-19 b和SA 2的肺保护作用。研究一种机制， 纤维蛋白原增强内皮细胞Sdc 1表达并减轻失血性休克后肺损伤我们 该提案提出了创新概念和新机制，为扭转 EOT。这对失血性休克的发病机制和治疗以及miRNA生物学具有重要意义 沿着改善出血性休克预后和减少死亡的潜力。

Project Summary/Abstract Trauma is the third leading cause of death. Of these deaths, hemorrhage remains the number one cause of early trauma deaths, though reductions in early mortality have occurred from modern resuscitation strategies. Further reductions in early deaths and later reductions in multi-organ failure (MOF) in survivors of hemorrhage represent opportunities to further improve care after hemorrhagic shock (HS). Our efforts are focused on reversal of the dysfunctional endothelium that follows trauma and HS, coined the “endotheliopathy of trauma” (EoT). We were the first to demonstrate in patients that syndecan-1 (Sdc1), a cell surface proteoglycan, is shed after trauma and that shedding was associated with poor outcomes. However, much less is known about Sdc1 expression and its effect on the endothelium, representing a gap in our knowledge. In our efforts to define the mechanisms for Sdc1 downregulation, we discovered that microRNA-19b (miR-19b) targets Sdc1, phenocopies the effects of HS in reducing Sdc1 expression, and contributes to the EoT, novel observations. Our data also demonstrates that miR-19b may be a therapeutic target, as antagomiRs reverse the deleterious effects of Sdc1 downregulation. We will also show that fibrinogen, as a key component in plasma and as an isolated therapeutic, co-localizes and engages Sdc1 on the endothelial cell surface to enhance Sdc1 expression, reduce miR-19b expression, and restore barrier integrity. Low systemic concentrations of fibrinogen after trauma are associated with increased severity of injury and are predictive of mortality. Nonetheless, in the US standard practice is to replace fibrinogen (using cryoprecipitate) only once levels are depressed and late during massive transfusion. Results of this study will support a major change in practice to include the early use of fibrinogen as an endothelial protector to lessen MOF and decrease mortality. Our preliminary data support the novel hypothesis that miRNA-19b-induced downregulation of Sdc1 following HS leads to breakdown of endothelial cell barrier integrity. We further hypothesize that fibrinogen restores endothelial cell Sdc1 expression by inhibiting miR-19b, engaging with Sdc1 on the cell surface, and activating PAK1 to restore barrier integrity and mitigate lung injury. We will test our hypotheses by pursuing the following aims: SA 1. Determine the role of miR-19b on endothelial cell Sdc1 downregulation following hemorrhagic shock and the pulmonary protective effects of miR-19b antagomiRs and SA2. Examine the mechanism by which fibrinogen enhances endothelial cell Sdc1 expression and mitigates lung injury after hemorrhagic shock. Our proposal puts forth innovative concepts and novel mechanisms that offer a new paradigm for the reversal of the EOT. This has significant implication to hemorrhagic shock pathogenesis and treatment, and miRNA biology along with the potential to improve outcomes and reduce deaths after hemorrhagic shock.