A role for autophagy in gut barrier disruption after alcohol and traumatic injury

 描述(申请人提供)：酒精滥用仍然是世界上导致发病率和过早死亡的主要原因之一，也是与创伤有关的主要风险因素。热损伤是一种主要创伤，每年导致40,000人住院，其中超过50%的患者在入院时血液中可检测到酒精(乙醇)水平。除了与创伤直接相关的许多并发症外，胃肠屏障和功能的破坏也经常发生。肠道屏障的这种破坏以及随后细菌和其他病原体的移位可能导致败血症、多器官衰竭和死亡。我们的实验室先前已经显示，在创伤性热中毒时，当酒精中毒时，肠上皮细胞增殖减少，炎性介质增加，细菌跨肠屏障移位。 受伤。然而，目前尚不清楚联合侮辱后肠道炎症和愈合受到干扰的机制。自噬是一个高度保守的细胞过程，已被证明是细胞增殖和凋亡的关键调节因子，而细胞增殖和凋亡是维持肠道内环境稳定所不可或缺的。自噬的改变可能会破坏肠道内的炎症反应和屏障完整性。因此，我们推测，自噬小体在肠上皮细胞中的积累有助于酒精和热损伤复合后的肠炎症和屏障渗漏。我们发现，综合伤害会导致LC_(33)/LC_(3I)比值升高。我们还表明，增加的自噬和炎症标记物可以通过在受到伤害时给予自噬抑制剂3-甲基腺嘌呤的治疗来挽救，进一步表明自噬在应对肠道损伤中发挥了作用。本研究将探讨自噬在复合损伤后炎症和肠屏障渗漏中所起的作用。目的1将描述肠上皮细胞复合损伤后自噬通量的变化，重点是肠上皮细胞内的标志蛋白 自噬信号通路。目的2将确定3-MA治疗和/或Lc3β敲除是否抑制自噬通量和恢复紧密连接蛋白的表达，并减少复合损伤后的急性炎症和肠漏。我们希望这项研究将阐明潜在的翻译贡献，以患者的治疗，以改善预后和存活率的创伤后，存在酒精中毒。

 DESCRIPTION (provided by applicant): Alcohol abuse remains one of the leading causes of morbidity and premature death in the world, and is a major risk factor associated with traumatic injury. Thermal injury is a major trauma that accounts for 40,000 hospitalizations annually, and over 50% of these patients have detectable blood alcohol (ethanol) levels at the time of admittance. In addition to the many complications associated directly with traumatic injury, disruptions of the gastrointestinal barrier and function frequently occur. This compromise of the gut barrier and subsequent translocation of bacteria and other pathogens can result in sepsis, multiple organ failure, and death. Our laboratory has previously shown decreases in gut epithelial cell proliferation, increases in inflammatory mediators, and bacterial translocation across the intestinal barrier when alcohol intoxication is present at the time of traumatic thermal injury. However, the mechanism by which gut inflammation and healing are perturbed following the combined insult is currently unknown. Autophagy is a highly conserved cellular process, and has been shown to be a key regulator of cellular proliferation and apoptosis, which are integral to maintaining gut homeostasis. Changes in autophagy may disrupt the inflammatory response and barrier integrity within the intestines. Thus, we hypothesize that the accumulation of autophagosomes in intestinal epithelial cells contributes to gut inflammation and barrier leakiness following combined alcohol and thermal injury. We have shown that the combined insult leads to an increase in LC3II/LC3I ratio. We have also shown that increased autophagy and inflammation markers can be rescued by treatment with the autophagy inhibitor 3- methyladenine given at the time of insult, further suggesting a role for autophagy in response to gut injury. The present study will investigate the role autophagy plays in inflammation and gut barrier leakiness following combined injury. Aim 1 will characterize the changes in autophagic flux following combined injury in intestinal epithelial cells, focusing on hallmark proteins within the autophagy signaling pathway. Aim 2 will determine if 3-MA treatment and/or LC3β-knockout suppress autophagic flux and restore tight junction protein expression and reduce acute inflammation and gut leakiness following combined injury. We expect this study will illuminate potential translational contributions to patient treatment to improve prognosis and survival following traumatic injury in the presence of alcohol intoxication.