Novel Nutrient Functions and Sensing Mechanisms

项目摘要 在我们最初的R35拨款申请提案中，我们描述了研究的两个主要目标 在营养功能和传感领域。一个是发现营养价值，或利益， 细菌产生的代谢产物对人体生理学的影响，这已经被共生理论所预测。 微生物与宿主动物的关系。第二个目标是发现新的 调节特定生理事件的机制，以响应特定营养素的缺乏， 包括脂肪酸、核苷酸和氨基酸。这些研究解决了一些基本问题， 与人类健康密切相关。对于这一“补充申请”，旨在获得资金， 购买一台设备来测量动物细胞中的氧化呼吸， 主要集中在第一个目标上。在线虫C.优雅，我们有 确定了某些细菌代谢物的意外有益作用，包括铁载体肠杆菌素 和细菌细胞壁组分肽聚糖胞肽对动物发育和行为的影响。 在R35赠款及其R01前体赠款的支持下，我们在理解和理解方面取得了令人兴奋的进展。 这些新功能背后的机制。这两种分子都进入宿主肠道的线粒体， 细胞，结合ATP合酶，并促进基本的线粒体功能。在尿肽的情况下，我们 已经发现有益分子是含有短AA链的二糖胞肽，并且他们 进入肠细胞的线粒体以抑制氧化应激。引人注目的是， 通过与ATP合酶的多个亚基结合，从而稳定复合物并促进 其活动。这一发现定义了ATP合酶的第一个激动剂。最近的研究使用培养的 人肠上皮细胞、来自疾病患者的成纤维细胞和用抗生素治疗的小鼠， 清楚地表明，在促进氧化磷酸化和抑制 哺乳动物细胞中的氧化应激。在未来几年，我们将继续扩大对 有效的muropeptides了解其结构特性，其在促进氧化磷酸化中的作用， 不同的哺乳动物组织，及其在抑制疾病中线粒体功能障碍的潜在作用 细胞和小鼠。这些研究具有很高的医学意义，因为众所周知线粒体功能障碍会导致 与广泛的人类疾病相关，包括主要的神经变性，心血管， 和代谢性疾病。我们还计划探索其他代谢物和营养传感的潜在作用 线粒体内稳态的机制。使用海马分析仪检查氧化呼吸 将大大促进这些拟议中的线粒体功能研究。

Project Summary In our original proposal for the R35 grant application, we described the two major goals of the research in the field of nutrient function and sensing. One is to discover nutrient value, or the benefits, of specific bacteria-produced metabolites on human physiology, which had been predicted by the symbiotic relationship between commensal microbes and host animals. The second goal was to uncover novel mechanisms that regulate specific physiological events in response to deficiency of specific nutrients that include fatty acids, nucleotides, and amino acids. These studies address fundamental questions that are closely related to human health. For this "Supplement Application" that aims to acquire funding for purchasing a piece of equipment to measure oxidative respiration in animal cells, the research strategy mainly focuses on the first goal. Using innovative genetic screens in the nematode C. elegans, we have identified unexpected beneficial roles of certain bacterial metabolites, including the siderophore enterobactin and bacterial cell wall components peptidoglycan muropeptides, on animal development and behaviors. Supported by the R35 grant and its R01 precursor grant, we have made exciting progress in understanding the mechanisms underlying these novel functions. Both molecules enter the mitochondria of host intestinal cells, bind to ATP synthase, and promote basic mitochondrial functions. In the case of muropeptides, we have found that beneficial molecules are disaccharide muropeptides containing a short AA chain, and they enter mitochondria of intestinal cells to repress oxidative stress. Strikingly, muropeptides execute this role by binding to multiple subunits of ATP synthase, which consequently stabilizes the complex and promotes its activity. This finding defined the first agonist of the ATP synthase. More recent studies using cultured human intestinal epithelial cells, fibroblasts from a disease patient, and mice treated with antibiotics have clearly indicated the roles of muropeptides in promoting oxidative phosphorylation and suppressing oxidative stress in mammalian cells. In the next several years, we will continue to expand the analyses on potent muropeptides to understand its structural property, its role in promoting oxidative phosphorylation in different mammalian tissues, and its potential effect in suppressing mitochondrial dysfunction in disease cells and mice. Such studies are of high medical significance, as mitochondrial dysfunction is well known to be associated with a broad range of human diseases including major neurodegenerative, cardiovascular, and metabolic diseases. We also plan to explore potential roles of other metabolites and nutrient sensing mechanisms in mitochondrial homeostasis. Having a Seahorse Analyzer to examine oxidative respiration would greatly facilitate these proposed studies on mitochondrial functions.