Impact of Stress on Alcoholic Gut Injury

 描述（由申请人提供）： 与酒精有关的健康问题是全球性的健康问题。超过50%的退伍军人使用酒精，近23%的人酗酒或酗酒。酒精性肝病（ALD）的发病机制涉及肠道屏障功能障碍引起的内毒素血症。大约25%的酗酒者会患上酒精性痴呆症，但使他们容易患上酒精性痴呆症的因素仍有待确定。压力和酒精中毒之间的关系是众所周知的，所以这个项目的重点是压力对酒精性组织损伤的影响。我们的初步研究表明不同类型的压力 破坏紧密连接（TJ），并通过涉及细胞内信号传导元件的机制增加肠上皮细胞的通透性。初步数据还表明，慢性束缚应激加剧了酒精诱导的肠道通透性和相关的肝损伤。众所周知，益生菌可促进胃肠道细胞存活和屏障功能。我们的初步数据表明，干酪乳杆菌（L。干酪素）改善应激和乙醇诱导的肠屏障功能障碍。基于这些结果，假设：a）应激诱导的细胞信号传导促进了肠上皮中酒精诱导的TJ破坏和屏障功能障碍，B）慢性应激通过CaV 1.3通道和JNK 2依赖性机制加剧了乙醇诱导的肠屏障功能障碍、内毒素血症和肝损伤，以及c）L.酪蛋白改善应激和乙醇诱导的肠屏障功能障碍、内毒素血症和肝损伤。使用肠上皮细胞和基因敲除小鼠的细胞培养模型，我们将确定：1）Ca 2+诱导的线粒体氧化应激介导应激诱导的Ask 1/MKK 7/JNK 2/c-Src信号传导的活化和肠上皮中的TJ破坏，2）糖皮质激素介导应激诱导的肠上皮细胞信号传导和酒精性肠通透性的恶化，3）应激激活的信号通路促进乙酰丙酮酸诱导的TJ破坏; 4）CaV1.3通道和[Ca 2 +]i介导慢性应激和乙醇对肠道和肝脏的协同作用; 5）JNK 2下调阻断应激和乙醇诱导的肠道屏障功能障碍和肝脏损伤;酪蛋白阻止应激诱导的细胞信号传导并减弱乙酰丙酮酸诱导的Caco-2细胞和小鼠离体肠中TJ破坏，7）L.酪蛋白减轻应激和乙醇诱导的肠道通透性和肝损伤;酪蛋白阻断肠道屏障功能障碍，并防止由应激和乙醇引起的肝损伤。这些研究的结果将直接影响应激诱导的肠粘膜稳态改变以及酒精性肝病的发病机制。 .

 DESCRIPTION (provided by applicant): Alcohol-related health problems are the worldwide health concern. More than 50% of Veterans use alcohol and nearly 23% are binge or heavy drinkers. Pathogenesis of alcoholic liver disease (ALD) involves endotoxemia caused by gut barrier dysfunction. About 25% of alcoholics develop ALD, but the factors that make them susceptible to ALD remain to be determined. The relationship between stress and alcoholism is well known, so this project focuses on the effects of stress on alcoholic tissue injury. Our preliminary studies showed that different types of stress disrupt tight junctions (TJs) and increase permeability in the intestinal epithelium by a mechanism that involves intracellular signaling elements. Preliminary data also indicated that chronic restraint stress exacerbates alcohol-induced gut permeability and associated liver injury. Probiotics are well known to promote gastrointestinal cell survival and barrier function. Our preliminary data indicated that Lactobacillus casei (L. casei) ameliorates stress and ethanol-induced gut barrier dysfunction. On the basis of these results it is hypothesized that: a) stress-induced cell signaling promotes alcohol-induced TJ disruption and barrier dysfunction in the intestinal epithelium, b) chronic stress exacerbates ethanol-induced gut barrier dysfunction, endotoxemia and liver injury by a CaV1.3 channel and JNK2-dependent mechanism, and c) L. casei ameliorates stress and ethanol-induced gut barrier dysfunction, endotoxemia and liver injury. Using a cell culture model of the intestinal epithelium and gene knock out mice we will determine that: 1) Ca2+-induced mitochondrial oxidative stress mediates stress-induced activation of Ask1/MKK7/JNK2/c-Src signaling and TJ disruption in the intestinal epithelium, 2) Glucocorticoids mediate stress-induced cell signaling in the intestinal epithelium and exacerbation of alcoholic gut permeability, 3) Stress-activated signaling promotes acetaldehyde-induced TJ disruption, 4) CaV1.3 channel and [Ca2+]i mediate the synergistic effects of chronic stress and ethanol on gut and liver, 5) Down regulation of JNK2 blocks stress and alcohol-induced gut barrier dysfunction and liver injury, 6) L. casei prevents stress-induced cell signalin and attenuates acetaldehyde-induced TJ disruption in Caco-2 cells and mouse intestine ex vivo, 7) L. casei attenuates stress and ethanol- induced gut permeability and liver injury in vivo, and 8) Peptide-like factor released by L. casei blocks gut barrier dysfunction and prevents liver injur caused by stress and ethanol. The outcome of these studies will have direct impact on the fields of stress-induced alteration of intestinal mucosal homeostasis as well as pathogenesis of alcoholic liver disease. .