Mechanisms of acute bowel injury Role of NF-KB

描述（由申请人提供）：坏死性小肠结肠炎（NEC）是新生儿重症监护室的主要问题，导致高发病率和死亡率。我的长期职业目标是阐明导致早产新生儿NEC发展的分子机制。这将导致预防和治疗这种毁灭性疾病。我的短期目标是获得知识和新的技术技能（如体内基因转移和激光捕获显微切割），使我能够在NEC研究领域做出重大贡献，并成为一名独立的研究科学家。该奖项将允许必要的支持，以实现这些目标，在博士的指导下迈克尔卡普兰和博士特伦斯巴雷特在一个良好的研究环境。我们有初步的证据表明，转录因子核因子-（NF-κ B）在肠发育调节和持续激活的新生大鼠模型NEC。我的总体假设是NEC是由于早产肠中NF-kB的长期激活引起的，NF-kB响应于细菌产物和局部产生的炎症脂质介质如血小板活化因子（PAF），引起中性粒细胞浸润和坏死。在早产儿中，这种持续的NF-kB激活导致促炎细胞因子（例如TNF）、趋化因子（例如MIP-2）和粘附分子（例如ICAM-1）的上调，这些因子放大炎症反应。结果，中性粒细胞被动员和激活，引起不可逆的组织损伤和坏死。本研究的主要目的是：1）研究NF-kB在新生儿缺氧-冷应激-配方奶粉喂养诱发的NEC模型中的活化情况; 2）研究NF-kB在新生儿NEC模型中的作用及其在急性肠损伤模型中的作用机制; 3）在新生儿NEC模型中检查调节肠道植物群和用益生菌治疗对肠道NF-κ B活化的影响。为此，提出了几种转基因小鼠模型：缺乏或过度表达NF-κ B的特定亚基的小鼠，表达NF-κ B依赖性荧光素酶的报告小鼠，最后将使用体内基因转移。了解NF-kB激活途径的发育差异可能会导致在坏死性小肠结肠炎早期阶段抑制NF-kB激活的特定策略。这可以防止其发展为不可逆的肠道损伤，并提高早产儿的存活率。

DESCRIPTION (provided by applicant): Necrotizing enterocolitis (NEC) is a major concern in the neonatal intensive care unit, causing great morbidity and mortality. My long-term career goal is to elucidate the molecular mechanisms that lead to the development of NEC in the premature newborn infant. This will lead to the prevention and treatment of this devastating disease. My short-term goals are to gain knowledge and novel technical skills (such as in vivo gene transfer and laser-capture microdissection) that will enable me to make significant contributions in the field of NEC research and to become an independent research scientist. This award would allow the necessary support to achieve these goals, under the mentorship of Dr. Michael Caplan and Dr. Terrence Barrett in an excellent research environment. We have preliminary evidence that the transcription factor nuclear factor- (NF-kB) is developmentally regulated in the intestine and is persistently activated in a neonatal rat model of NEC. My overall hypothesis is that NEC results from the prolonged activation of NF- kB in the premature intestine in response to bacterial products and locally produced inflammatory lipid mediators such as platelet-activating factor (PAF), causing neutrophil infiltration and necrosis. In the premature infant, this persistent NF-kB activation leads to the upregulation of pro-inflammatory cytokines (e.g. TNF), chemokines (e.g. MIP-2) and adhesion molecules (e.g. ICAM-1) which amplify the inflammatory response. As a result, neutrophils are mobilized and activated, causing irreversible tissue injury and necrosis. The following specific aims will be addressed: 1) to characterize NF-kB activation in the neonatal model of NEC induced by hypoxia-cold stress-formula feeding; 2) to study the role of NF-kB in the neonatal NEC model and its mechanisms of action in a model of acute bowel injury; 3) to examine the effect of modulating the intestinal flora and treatment with probiotics on intestinal NF-KB activation in the neonatal NEC model. To do so, several transgenic mice models are proposed: mice lacking or over-expressing a specific subunit of NF-kB, reporter mice expressing NF-kB-dependent luciferase and finally in vivo gene transfer will be used. Understanding the developmental differences in the NF-kB activating pathway might lead to specific strategies geared at inhibiting NF-kB activation in the early stages of necrotizingenterocolitis. This could prevent its progression toward irreversible intestinal damage and improve the survival of premature infants.