Small Molecule Signaling in Caenorhabditis elegans

描述(申请人提供)：线虫秀丽线虫是生物医学研究中最重要的模式生物之一，因为它具有生物可控性，而且它的许多生理途径与人类的相应途径有很强的相似性。该项目的目标是对线虫高度发达的基因组学和蛋白质组学进行补充，对其代谢组进行全面的结构和功能表征，令人惊讶的是，这方面的探索仅限于非常有限的程度。这一努力是由一系列证据推动的，这些证据表明，结构基本上未知的小分子在线虫的内分泌和外分泌信号中发挥重要作用，特别是在调节寿命、发育和新陈代谢的关键途径中。建议研究的中心是使用新的核磁共振波谱方法，这种方法允许分析复杂的小分子混合物，并极大地加快了被检测化合物的结构阐明过程和功能表征。这种方法学允许比较来自不同线虫突变菌株的复杂代谢物样本，并确定其生物合成因特定突变而强烈上调或下调的化合物的化学结构。在这个项目中，选择了少数突变菌株，它们的表型表明影响寿命、发育或脂肪代谢的小分子信号存在缺陷。核磁共振波谱将被用来检测和识别与这些表型相关的化合物。随后，鉴定出的化合物的合成样品将经过化学遗传筛选，以确定对寿命、发育调节和脂肪代谢调节的影响。在野生型线虫中显示活性的化合物将与代表与衰老和发育有关的关键遗传途径的突变或RNAi菌株进行额外的分析。该项目的成功完成将为线虫代谢组提供部分结构和功能注释，大大增加我们对线虫生物学基本途径和哺乳动物相应疾病相关途径的理解。产生的小分子知识不仅将使今后的努力能够针对更多样化的化学遗传筛选，探索线虫生物学和生态学的其他方面，而且还将有助于农业或医学上相关的线虫物种的研究。此外，为表征线虫信号分子而开发的方法将有助于对来自其他模式生物的小分子代谢物的结构和功能表征进行类似的研究。 公共卫生相关性：与老龄化相关的普遍生理变化反映在许多疾病的发病率随年龄的增加而增加，包括糖尿病、癌症、神经疾病、心脏病和骨质疏松症。在线虫中，被称为蛔虫苷的内源化合物已被证明显著延缓衰老的影响并延长寿命。这项拟议的研究旨在探讨这些化合物和其他内源性化合物调节线虫寿命和发育的生物学机制，这将有助于我们理解人类衰老的原因。

DESCRIPTION (provided by applicant): The nematode Caenorhabditis elegans is one of the most important model organisms for biomedical research, because of its biological tractability and because many of its physiological pathways show strong analogies to corresponding pathways in humans. The goal of this project is to complement the highly developed genomics and proteomics of C. elegans with a comprehensive structural and functional characterization of its metabolome, which, surprisingly, has been explored to only a very limited extent. This effort is motivated by several lines of evidence indicating that small molecules of largely undetermined structure play important roles in C. elegans endocrine and exocrine signaling, specifically in key pathways regulating lifespan, development, and metabolism. Central to the proposed research is the use of new NMR-spectroscopic methodology that permits the analysis of complex small molecule mixtures and greatly accelerates both the structure elucidation process and the functional characterization of the detected compounds. This methodology permits to compare complex metabolite samples derived from different C. elegans mutant strains, and to identify the chemical structures of compounds whose biosynthesis is strongly up- or downregulated as a result of a specific mutation. For this project, a small number of mutant strains were selected whose phenotypes suggest a defect in small-molecule signaling affecting lifespan, development, or fat metabolism. NMR-spectroscopy will be used to detect and identify compounds that correlate with these phenotypes. Subsequently, synthetic samples of the identified compounds will be subjected to chemical genetic screens to determine effects on lifespan, developmental regulation and fat metabolism regulation. Compounds that show activity in wild-type C. elegans will be subjected to additional assays with mutant or RNAi strains representative of key genetic pathways related to ageing and development. Successful conclusion of this project will provide a partial structural and functional annotation of the C. elegans metabolome, substantially increasing our understanding of fundamental pathways in C. elegans biology and corresponding disease-relevant pathways in mammals. The small-molecule knowledge generated will not only enable future efforts aimed at more varied chemical genetic screens exploring additional aspects of the biology and ecology of C. elegans, but also of nematode species relevant in agriculture or medicine. Furthermore, methodology developed for characterizing C. elegans signaling molecules will facilitate similar studies toward structural and functional characterization of small molecule metabolites from other model organisms. PUBLIC HEALTH RELEVANCE: The pervasive physiological changes associated with aging are reflected in age- dependent increases in the incidence of many diseases, including, diabetes, cancer, neurological disorders, heart disease, and osteoporosis. In nematodes, endogenous compounds called ascarosides have been shown to significantly retard the effects of ageing and increase lifespan. The proposed study aims to investigate the biological mechanisms through which these and other endogenous compounds modulate lifespan and development in nematodes, which will contribute to our understanding of the causes of ageing in humans.