CAREER: Understanding and Harnessing Host-derived Small RNAs Against Opportunistic Pathogens

复杂的微生物群落寄生在所有生物身上。这些群落组成了一个微生物组。宿主和各种微生物群之间的交流有助于维持人体健康。破坏这种交流可能导致感染和疾病。近年来，研究表明小RNA分子（sRNA）是关键的通讯分子。了解不同类型的sRNAs如何调节口腔和呼吸系统中的病原体是本项目的重点。该研究项目将与一项教育和推广计划相结合。这些努力将使代表性不足的高中生和本科生为从事STEM职业做好准备。他们还将把真实的动手实验整合到本科课程中，并开发低成本的生物工具包和虚拟教学方法，以接触偏远地区的学生。该项目将解决在理解宿主来源的细胞外sRNAs在宿主-微生物群相互作用中所起作用的知识差距。目前缺乏能够解锁宿主srna功能的方法，主要是由于三个限制。首先，天然srna极易降解。其次，很难区分宿主和细菌之间短sRNA片段的来源。第三，宿主srna在细菌内部的含量非常低。该项目的长期目标是深入了解宿主衍生的sRNAs作为一类针对机会性病原体的新型防御分子，并进一步将宿主sRNAs重新用作潜在的抗菌药物。为了实现这一目标，该项目将(1)通过结合化学修饰的核苷酸来优化sRNA的稳定性和功能，并定义结构-功能关系；(2)采用结构建模、细菌遗传学和生化分析来剖析宿主sRNA如何被口腔和气道机会性细菌内化；(3)开发一种强大的方法来发现迄今为止未知的具有抗菌活性的宿主sRNA。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Complex communities of microbes colonize all living creatures. These communities comprise a microbiome. Communication between the host and various microbiomes help to maintain human health. Disrupting this communication can lead to infection and disease. Recently, studies have implicated small RNA molecules (sRNA) as key communication molecules. Understanding how different types of sRNAs regulate pathogens in oral and respiratory systems is the focus of this project. The research program will be integrated with an education and outreach plan. These efforts will prepare under-represented high-school students and undergraduates to pursue careers in STEM. They will also integrate authentic hands-on experiments into undergraduate courses and develop low-cost biology kits and virtual teaching methods to reach students in remote areas. This project will address the knowledge gap in understanding the roles played by host-derived extracellular sRNAs in host-microbiota interactions. There is a lack of enabling methodologies to unlock the functions of host sRNAs largely due to three limitations. First, native sRNAs are highly susceptible to degradation. Second, it is difficult to distinguish the origins of short sRNA fragments between host and bacteria. Third, host sRNAs are present inside bacteria at very low levels. The long-term project goal is to achieve in-depth understanding of host-derived sRNAs as a new class of defense molecules targeting opportunistic pathogens, and, furthermore, to repurpose host sRNAs as potential antimicrobial agents. To achieve this goal, this project will (1) optimize sRNA stability and functions by incorporating chemically modified nucleotides and define structure-function relationships, (2) employ structural modeling, bacterial genetics, and biochemical assays to dissect how host sRNAs are internalized by oral and airway opportunistic bacteria, and (3) develop a powerful methodology to uncover hitherto unknown host sRNAs with antimicrobial activities.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.