Molecular Control of Gut Permeability in Trauma

描述（由申请人提供）： 与创伤相关的全身炎症和多器官衰竭是美国士兵和退伍军人死亡和发病的主要原因。肠屏障功能障碍通过提供血浆渗漏和细菌移位至循环的主要部位而在创伤后并发症如脓毒症的发展中起关键作用。尽管肠功能障碍在创伤后并发症的发病机制中的重要性已被充分认识，但肠对严重烧伤（一种主要形式的创伤）的通透性反应尚未得到很好的表征，其细胞和分子机制仍然知之甚少。本研究的目的是阐明热损伤时肠漏的细胞特异性机制。我们建议确定棕榈酰化在介导热损伤时肠上皮细胞高通透性的功能，调节和分子机制。待检验的假设是，烧伤通过上调肠上皮细胞中的蛋白棕榈酰化来刺激蛋白棕榈酰化 DHHC异构体。棕榈酰化通过刺激ROCK依赖的细胞骨架收缩和上皮细胞中claudins/ZO 2介导的连接解离导致上皮屏障失效，从而促进烧伤诱导的肠道通透性增高的发病机制。三 本发明的具体目的是：1）研究棕榈酰化在肠上皮屏障损伤中的功能和调节，2）。检查棕榈酰化在热损伤期间肠上皮中的调节作用，和3）鉴定棕榈酰化在介导上皮高通透性中的分子靶点。研究设计采用了体内、离体和体外模型，这些模型将分子和遗传方法纳入临床相关创伤条件下的生理实验中。本研究的意义在于 有可能确定蛋白质棕榈酰化在创伤发病机制中的新作用。研究工作获得的数据不仅有助于胃肠道病理生物学的进步，而且对开发针对创伤或炎症性疾病患者肠道屏障损伤的有效疗法或手术干预措施具有临床意义。

DESCRIPTION (provided by applicant): Systemic inflammation and multiple organ failure associated with trauma are a major cause of mortality and morbidity in American soldiers and veterans. Gut barrier dysfunction plays a critical role in the development of posttraumatic complications such as sepsis by providing the major site for plasma leakage and bacterial translocation to the circulation. Despite the well- recognized importance of gut dysfunction in the pathogenesis of posttraumatic complications, the intestinal permeability response to severe burns, a major form of trauma, has not been well characterized, and its cellular and molecular mechanisms remain poorly understood. The goal of this study is to elucidate the cell-specific mechanisms of leaky guts during thermal injury. We propose to define the function, regulation and molecular mechanisms of palmitoylation in mediating gut epithelial hyperpermeability during thermal injury. The hypothesis to be tested is that burn injury stimulates protein palmitoylation in the gut epithelial cells through upregulation of DHHC isoforms. Palmitoylation contributes to the pathogenesis of burn-induced gut hyperpermeability by stimulating ROCK-dependent cytoskeleton contraction and claudins/ZO2- mediated junction dissociation in the epithelial cells leading to epithelial barrier failure. Three specific aims are developed in this proposal to: 1) study the function and regulation of palmitoylation in gut epithelial barrier injury, 2). examine the regulatory role of palmitoylation n gut epithelium during thermal injury, and 3) identify molecular targets of palmitoylation in mediating epithelial hyperpermeability. The study design employs complimentary in vivo, ex vivo, and in vitro models that incorporate molecular and genetic approaches into physiological experiments under clinically relevant trauma conditions. The significance of this study lies in the potential to identify a new role of protein palmitoylation in pathogenesis during trauma. Data derived from the research work will not only contribute to the advancement of gastrointestinal pathobiology, but also has clinical implications in the development of effective therapies or surgical interventions against gut barrier injury in patients with trauma or inflammatory diseases.