Microbial regulation of DNA repair in intestinal epithelial cells

背景***肠道中含有丰富的微生物和肠上皮细胞（IEC）集落，它们对于调节这些微生物与宿主的相互作用至关重要。IEC表达许多模式识别受体（PRR），使它们能够感知和响应微生物。这是至关重要的，因为微生物可以产生损害DNA的产物，而IEC非常容易积累突变，因为它们经常分裂，每次都必须复制它们的DNA。虽然在IEC中有许多保护性DNA修复途径，但这些修复机制如何受到肠道微生物产物的调节这一基本问题仍未得到解答，尽管这种调节途径的存在可能对基本肠道生理学产生重要影响。***目的和目的***拟议项目的总体目标是表征肠道微生物群在调节宿主细胞DNA修复中的作用。我们将通过三个目标来实现这一目标。* * *的目标1。确定不同PRR在IEC上的激活是否调节DNA修复机制。我们将重点研究PRR的toll样受体（TLR）类别。我们将使IEC暴露于已知能激活不同TLR的微生物分子中，并评估这如何改变DNA修复蛋白的表达和每种DNA修复途径的效率。* * *的目标2。确定微生物代谢产物如何改变DNA修复和诱导DNA损伤。微生物代谢副产物对IEC有多种影响，但对IEC DNA修复的影响尚不清楚。当暴露于特定的微生物代谢物时，我们将检查IEC中不同DNA修复途径的活性，并确定IEC是否更容易受到可能改变其功能的突变的影响。* * *的目标3。确定饮食如何调节肠道微生物群诱导的DNA损伤。饮食在决定肠道菌群产生哪些代谢物方面起着重要作用。然而，对于哪些饮食因素调节直接靶向DNA的微生物产物的产生或IEC DNA修复的效率，人们知之甚少。我们将使用细胞培养和小鼠实验来评估不同的营养是否直接改变这些化合物的产生或改变微生物调节DNA修复的能力。******影响***DNA修复是一个基本的生物过程，在快速分裂IEC中尤为重要。该项目将为我们团队和其他人的未来研究建立必要的框架，因为它将产生对特定微生物物种和饮食成分如何影响调节肠道生理的关键细胞类型的基本理解。这个项目也将使我小组的学生实习生接触到令人兴奋的新技术和合作，这将帮助他们发展技能和关系，这将有利于他们未来的科学事业。**

BACKGROUND ***The intestine contains an abundant colony of microorganisms and intestinal epithelial cells (IEC) that are critical for regulating the interaction of these microbes with the host. IEC express numerous pattern recognition receptors (PRR) that allow them to sense and respond to microbes. This is critical since microbes can produce products that damage DNA and IEC are very susceptible to accumulating mutations because they divide frequently and must reproduce their DNA each time. While numerous protective DNA repair pathways operate within IEC, the basic question of how these repair mechanisms are regulated by intestinal microbial products remains unanswered despite the fact that the existence of such regulatory pathways could have important consequences for fundamental intestinal physiology.***OBJECTIVE AND AIMS***The overall objective of the proposed program is to characterize the role of intestinal microbiota in regulating DNA repair in host cells. We will accomplish this by addressing three aims.***Aim 1. Determine if the activation of different PRR on IEC regulates DNA repair mechanisms. We will focus our work on the Toll-like receptors (TLR) category of PRR. We will expose IEC to microbial molecules known to activate different TLR and evaluate how this changes DNA repair protein expression and the efficiency of each DNA repair pathway. ***Aim 2. Determine how microbial metabolic products alter DNA repair and induce DNA damage. The byproducts of microbial metabolism exert many effects on IEC yet their influence on IEC DNA repair is unknown. We will examine the activity of different DNA repair pathways in IEC when exposed to specific microbial metabolites and determine if the IEC become more or less susceptible to the development of mutations that could alter their function.***Aim 3. Determine how diet regulates microbiota-induced DNA damage in the intestine. Diet plays a significant role in determining what metabolites are produced by intestinal microbiota. However, little is known about what dietary factors regulate the generation of microbial products that directly target DNA or the efficiency of IEC DNA repair. We will use cell culture and mouse experiments to evaluate if different nutrients directly alter production of these compounds or alter the ability of microbes to regulate DNA repair.******IMPACT***DNA repair is a fundamental biological process that is especially important in rapidly dividing IEC. The proposed project will establish a necessary framework for future research by our team and by others since it will generate a fundamental understanding of how specific microbial species and dietary components can influence the lynchpin cell type regulating intestinal physiology. This project will also expose student trainees in my group to exciting new techniques and collaborations that will help them develop both skills and relationships that will benefit their future scientific careers. **