MOLECULAR BASIS FOR EPITHELIAL BARRIER DYSFUNCTION/PROJECT 2

多器官功能障碍综合征（MODS）的发展是严重创伤后常见的，特别是当患者发生休克、代谢性酸中毒并需要多次输注浓缩红血时。出血和创伤后MODS的发展明显与全身炎症反应的程度有关。因此，研究人员投入了大量的精力来了解更多关于各种信号的信息。 导致先天免疫系统激活和创伤/出血后促炎介质产生的途径。虽然还有很多东西需要学习，但许多关键信号通路的重要元素已经被阐明。相比之下，创伤后的生物化学和细胞生物学基础 器官功能障碍本身仍然知之甚少。然而，众所周知，人类MODS的组织病理学是非常温和的;大量细胞死亡，无论是由于坏死还是凋亡，几乎可以肯定不是MODS的原因。相反，MODS发展的最后一步可能是多器官实质细胞的广泛功能障碍，这是由于控制不良的全身炎症反应的有害作用。 反应因此，一个巨大的未开发的研究领域可以总结为这个问题：创伤后炎症反应的失调如何导致实质细胞功能障碍？基于我们在上一个资助周期的工作，以及我们的研究小组最近进行的其他工作，我们假设创伤后MODS的结果，至少部分是由于以下因素的表达和亚细胞定位的扰动： 在多种上皮组织中，例如在肺、肝和肠中发现的紧密连接（TJ）蛋白。因为研究肠粘膜中的上皮TJ功能比研究其他组织中的上皮TJ功能相对容易，所以我们的努力将集中在肠道上，尽管关键发现将通过进行实验来研究其他器官中的上皮TJ功能来证实（即，肝和肺）。将根据这些目标组织工作。(1)：检验假设， 小鼠的失血性休克/复苏（HS/R）通过依赖于一氧化氮、活性氧和/或过氧亚硝酸盐的形成的机制导致多种上皮细胞中TJ结构和功能的改变。(2)检验以下假设：HS/R诱导的肠、肝和肺上皮TJ结构和功能紊乱至少部分是通过HMGB 1和/或其他相关配体与晚期糖基化终产物受体的结合介导的。 (3)检验IL-6是HS/R诱导的肠、肝和肺上皮TJ结构和功能紊乱的关键介质的假设。(4)检验以下假设：及时给予烟酰胺腺嘌呤二核苷酸（NAD +）治疗可以改善HS/R诱导的肠道、肺和肝上皮功能障碍的改变。

Development of the multiple organ dysfunction syndrome (MODS) is a common after severe trauma, particularly when patients develop shock, metabolic acidosis, and require multiple transfusions of packed red blood. The development of MODS after hemorrhage and trauma clearly is related to the magnitude of the resulting systemic inflammatory response. Accordingly, investigators have invested a great deal of effort to learn more about various signaling pathways that lead to the activation of the innate immune system and the elaboration of pro-inflammatory mediators after trauma/hemorrhage. Although a great deal remains to be learned, important elements of many of the key signaling pathways already have been elucidated. In contrast, the biochemical and cell biological underpinnings for post-traumatic organ dysfunction per se remain very poorly understood. It is known, however, that the histopathology of MODS in humans is remarkably bland; massive cell death, whether due to necrosis or apoptosis, is almost certainly not the cause of MODS. Rather, the final step in the development of MODS is probably the widespread dysfunction of parenchymal cells in multiple organs as a result of the deleterious effects of a poorly controlled systemic inflammatory response. Thus, a hugely under-explored area of research can be summarized by this question: How does post-traumatic dysregulation of the inflammatory response lead to parenchymal cell dysfunction? Based on our work during the previous cycle of funding of this grant as well as other work performed recently by our research group, we hypothesize that post-traumatic MODS results, at least in part, from perturbations in the expression and subcellular localization of tight junction (TJ) proteins in multiple epithelial tissues, such as those found in the lung, liver and gut. Because it is relatively easier to investigate epithelial TJ function in the intestinal mucosa than it is in other tissues, our efforts will focus on the gut, although key findings will be corroborated by carrying out experiments to study epithelial TJ function in other organs (i.e., the liver and lungs). The work will be organized under these Aims. (1): Test the hypothesis that hemorrhagic shock/resuscitation (HS/R) in mice leads to alterations in TJ structure and function in multiple epithelia via mechanisms that depend on the formation of nitric oxide, reactive oxygen species, and/or peroxynitrite. (2) Test the hypothesis that HS/R-induced derangements in gut, liver and lung epithelial TJ structure and function are mediated, at least, in part by binding of HMGB 1 and/or other related ligands to the receptor for advanced glycation end-products. (3) Test the hypothesis that IL-6 is a key mediator of HS/R-induced derangements in gut, liver and pulmonary epithelial TJ structure and function. (4) Test the hypothesis that timely treatment with nictoninamide adenine dinucleotide (NAD +) can ameliorate HS/R-induced alterations in gut, lung, and liver epithelial dysfunction.