Endothelial injury and repair following hemorrhagic shock

项目摘要/摘要 创伤是导致死亡的第三大原因。在这些死亡中，出血仍然是导致死亡的首要原因 早期创伤死亡，尽管通过现代复苏策略降低了早期死亡率。 进一步减少出血幸存者的早期死亡和后来的多器官衰竭(MOF) 代表着进一步改善失血性休克(HS)后护理的机会。我们的努力集中在扭转 对于创伤和HS后的内皮功能障碍，人们创造了“创伤内皮病”(EoT)。我们 是第一个在患者身上证明Syndecan-1(Sdc1)，一种细胞表面蛋白多糖，在创伤后脱落 而这种减产与糟糕的结果有关。然而，对Sdc1表达的了解要少得多 以及它对血管内皮细胞的影响，代表着我们知识上的一个缺口。在我们努力定义机制的过程中 对于Sdc1的下调，我们发现microRNA-19b(miR-19b)针对Sdc1，表现出复制的效应 HS在减少Sdc1的表达，并有助于EoT，新的观察结果。我们的数据还表明 MiR-19b可能是一个治疗靶点，因为对映体逆转了Sdc1下调的有害影响。 我们还将证明，纤维蛋白原作为血浆中的关键成分和作为一种孤立的治疗手段，共同定位于 并与内皮细胞表面的Sdc1结合，增强Sdc1的表达，降低miR-19b的表达 恢复屏障完整性。创伤后全身纤维蛋白原浓度低与升高有关 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 (使用冷沉淀物)在大量输血期间只有一次水平下降和延迟。这项研究的结果 将支持在实践中进行重大改变，包括早期使用纤维蛋白原作为内皮保护剂，以减少 MOF和降低死亡率。 我们的初步数据支持新的假设，即miRNA-19b诱导以下Sdc1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可以恢复 通过抑制miR-19b、与细胞表面的Sdc1结合和激活内皮细胞Sdc1的表达 PAK1以恢复屏障完整性和减轻肺损伤。我们将通过追求以下内容来验证我们的假设 目的：SA 1.确定miR-19b对失血性休克后内皮细胞Sdc1下调的作用 以及miR-19b对映体和SA2的肺保护作用。研究通过什么机制 纤维蛋白原促进内皮细胞Sdc1表达，减轻失血性休克后肺损伤。我们的 提案提出了创新的概念和新的机制，为扭转经济衰退提供了新的范式 埃奥特。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。 以及在失血性休克后改善预后和减少死亡的可能性。

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.