Mechanisms of Gastrointestinal Epithelial Cell Injury & Repair During Development

胃肠道上皮细胞损伤的机制

• 批准号: 8399767
• 负责人: Steven James McElroy
• 金额: $ 12.27万
• 依托单位: UNIVERSITY OF IOWA
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8399767
• 关键词: Mechanisms; Gastrointestinal; Epithelial; Cell; Injury

Premature infants face a host of unique issues due to their developmental immaturity. One of the most devastating is necrotizing enterocolitis (NEC), which yearly kills 12 babies per 100,000 live births in the US and frequently leaves survivors with severe feeding issues, liver failure, and neurodevelopmental disability. Understanding mechanisms of intestinal injury and repair in developing intestine is key to developing new prevention and therapeutic strategies for NEC. This proposal will investigate the mechanisms of gastrointestinal epithelial cell injury and repair during development by testing the hypothesis that the intestine of premature infants and newborn mice is more susceptible to TNF-induced injury because of an ontogenically normal decrease in expression and activation of EGFR. This hypothesis will be examined through the following specific Aims: 1) Define the effects of TNF on intestinal injury and apoptosis at different developmental stages. This will be accomplished using histopathologic injury scores of early intestinal damage as well as immunofluorescence and immunohistochemical assays for apoptosis; 2) Determine the effects of TNF on EGFR inhibition in neonates compared to adults. We will study the effects of TNF on multiple EGFR phosphorylation sites and down-stream targets, and the role of EGFR internalization in TNF-stimulated EGFR inhibition. This aim will utilize immunofluorescence and western blot analysis to study the down-stream targets of EGFR activation; and 3) Determine the role of EGFR activation in protecting against TNF induced injury using pharmacologic and genetic models of EGFR activation. This aim will build on techniques developed in Aim 1 and 2 and apply them to mice with constitutively active EGFR, pharmacologically active EGFR, and deficiency of EGFR. Overall, these studies will reveal the roles of TNF and EGFR in intestinal injury processes in developing intestinal tissue, and will identify potential novel avenues of therapy and chemoprevention. In addition to the above studies, this proposal will greatly enhance career development through didactic training in cell biology, developmental biology, and statistics; by providing mentoring from a strong laboratory; and by utilizing the strong resources uniquely available at Vanderbilt to foster independent investigation in gastrointestinal disease.

早产儿由于发育不成熟而面临许多独特的问题。其中最具破坏性的是坏死性小肠结肠炎（NEC），每年在美国每10万名活产婴儿中有12名婴儿死亡，并经常使幸存者出现严重的喂养问题，肝功能衰竭和神经发育障碍。了解发育期肠损伤和修复的机制是开发NEC新的预防和治疗策略的关键。该提案将通过测试早产儿和新生小鼠的肠道更容易受到TNF诱导的损伤的假设，因为EGFR的表达和激活的个体发育正常减少，来研究发育过程中胃肠道上皮细胞损伤和修复的机制。本研究的目的是：1）明确TNF在不同发育阶段对肠道损伤和细胞凋亡的影响。这将使用早期肠损伤的组织病理学损伤评分以及细胞凋亡的免疫荧光和免疫组织化学测定来完成; 2）确定与成人相比，新生儿中TNF对EGFR抑制的影响。我们将研究肿瘤坏死因子对多个EGFR磷酸化位点和下游靶点的影响，以及EGFR内化在肿瘤坏死因子刺激的EGFR抑制中的作用。该目的将利用免疫荧光和蛋白质印迹分析来研究EGFR活化的下游靶点;和3）使用EGFR活化的药理学和遗传学模型来确定EGFR活化在保护免受TNF诱导的损伤中的作用。这一目标将建立在目标1和2中开发的技术基础上，并将其应用于具有组成型活性EGFR、非活性EGFR和EGFR缺陷的小鼠。总的来说，这些研究将揭示TNF和EGFR在肠损伤过程中的作用，并将确定潜在的治疗和化学预防的新途径。除了上述研究外，该提案还将通过细胞生物学、发育生物学和统计学的教学培训，通过强大的实验室提供指导，并通过利用范德比尔特独特的强大资源，促进胃肠道疾病的独立研究，大大提高职业发展。