Modulation of Pulmonary Vascular Permeability and Inflammation by Mesenchymal Stem Cells (MSCs) in Hemorrhagic Shock

 描述（由申请人提供）：创伤性损伤是全球平民和军人群体中儿童和成人死亡和残疾的主要原因。5出血性休克（HS）的特征之一是创伤性损伤后快速失血导致的全身反应，导致内皮损伤、炎症、异常凝血、组织水肿和终末器官损伤。HS与急性肺损伤（ALI）和急性呼吸窘迫综合征（ARDS）的高发病率相关（14-20%的ICU患者），导致显著的发病率和死亡率。8，9 8-13除了复苏范例和支持性治疗外，目前很少有治疗创伤中肺水肿和ARDS的治疗方法。已经显示在以血管损害和炎症为特征的多种病症中具有治疗潜力。1，15-31我们的小组已经显示IV MSC减弱创伤性脑损伤（TBI）后的血脑屏障（BBB）通透性以及HS后的肺通透性和炎症。1，[15] MSC如何工作的机制在很大程度上是未知的。包括我们自己在内的许多研究小组已经表明，MSC的有益作用是由可溶性因子介导的。4，32在我们过去的研究中，我们确定了MSC产生和诱导的可溶性因子-TIMP 3（基质金属蛋白酶组织抑制剂-3）-可以通过调节内皮粘附连接和血管稳定性来重现MSC对内皮渗透性的保护作用。在我们目前的研究中，我们有证据表明TIMP 3可以单独调节失血性休克诱导的肺血管通透性。我们的数据支持TIMP 3收紧血肺血管屏障的假设。我们的总体机制假设是，静脉内（IV）MSC通过HS后TIMP 3的产生和诱导降低肺通透性、肺水肿并改善肺功能。我们假设IV TIMP 3将概括IV MSC的保护作用。我们的目标是确定MSC在失血性休克诱导的血管通透性和炎症中的作用机制，并研究MSC衍生蛋白-TIMP 3的作用和治疗潜力。目的1是体外目的，旨在通过研究TIMP 3和MSC介导的对肺内皮通透性的影响中涉及的功能、结构域和信号通路来阐明TIMP 3的作用机制。目的2旨在使用建立的失血性休克和创伤的小鼠模型回答IV MSC（具有和不具有TIMP 3表达）和TIMP 3是否减弱HS诱导的肺渗透性的问题。目的3研究TIMP 3基因敲除小鼠中TIMP 3和MSCs的作用。我们在这一领域的研究工作的最终长期目标是将我们的研究结果从“板凳t床边”转化为创伤治疗选择，可以减轻患者的预后。

 DESCRIPTION (provided by applicant): Traumatic injury is the leading cause of death and disability in children and adults worldwide in both civilian and military populations.5 One of the hallmarks of hemorrhagic shock (HS), a condition resulting from rapid blood loss after traumatic injury, is the onset of a systemic response that results in endothelial injury, inflammation, aberrant coagulation, tissue edema and end organ injury. HS is associated with a high incidence of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) (14-20% of ICU patients) that results in significant morbidity and mortality.8, 9 8-13 Aside from resuscitatio paradigms and supportive therapy there are currently few treatments to treat lung edema and ARDS in trauma.14 Mesenchymal stem cells (MSCs) have been shown to have therapeutic potential in multiple conditions characterized by vascular compromise, and inflammation.1, 15-31 Our group has shown that IV MSCs attenuate blood brain barrier (BBB) permeability after traumatic brain injury (TBI) and also lung permeability and inflammation after HS.1, 15 The mechanisms of how MSCs work are largely unknown. Many groups including our own have shown that the beneficial effects of MSCs are mediated by soluble factors.4, 32 In our past studies, we identified a soluble factor produced and induced by MSCs - TIMP3 (Tissue Inhibitor of Matrix Metalloproteinase-3) - that can recapitulate the protective effects of MSCs on endothelial permeability by modulating endothelial adherens junctions and vascular stability. In our current studies, we have evidence suggesting that TIMP3 can separately modulate pulmonary vascular permeability induced by hemorrhagic shock. Our data support the hypothesis that TIMP3 tightens the blood-lung vascular barrier. Our overall mechanistic hypothesis is that intravenous (IV) MSCs decrease lung permeability, lung edema and improve lung function through production and induction of TIMP3 after HS. We hypothesize that IV TIMP3 will recapitulate the protective effects of IV MSCs. It is our goal to define the mechanisms of action of MSCs in hemorrhagic shock induced vascular permeability and inflammation and to investigate the role and therapeutic potential of the MSC derived protein - TIMP3. Aim 1 is an in vitro aim that is designed to elucidate mechanisms of action of TIMP3 through investigations of function, domains and signaling pathways involved in TIMP3 and MSC mediated effects on pulmonary endothelial permeability. Aim 2 is designed to answer the question of whether IV MSCs (with and without TIMP3 expression) and TIMP3 attenuate HS induced lung permeability using an established mouse model of hemorrhagic shock and trauma. Aim 3 is designed to study the effects of TIMP3 and MSCs in the TIMP3 knock-out mouse. The final long-term goal of our research effort in this area is to translate our findings from "bench t bedside" to provide a treatment option in trauma that can mitigate patient outcomes.