Novel Nutrient Functions and Sensing Mechanisms

项目概要 在我们最初的 R35 拨款申请提案中，我们描述了该研究的两个主要目标 在营养功能和传感领域。一是发现特定食物的营养价值或益处 细菌产生的代谢物对人体生理学的影响，这是共生论所预言的 共生微生物与宿主动物之间的关系。第二个目标是发现小说 调节特定生理事件以响应特定营养素缺乏的机制 包括脂肪酸、核苷酸和氨基酸。这些研究解决了以下基本问题： 与人体健康密切相关。对于这个旨在获得资金的“补充申请” 购买一台设备来测量动物细胞的氧化呼吸，研究策略 主要关注第一个目标。通过在线虫秀丽隐杆线虫中的创新遗传筛选，我们获得了 发现了某些细菌代谢物（包括铁载体肠杆菌素）的意想不到的有益作用 和细菌细胞壁成分肽聚糖胞肽，对动物发育和行为的影响。 在 R35 拨款及其 R01 前驱拨款的支持下，我们在理解方面取得了令人兴奋的进展 这些新功能背后的机制。两种分子都进入宿主肠道的线粒体 细胞，与 ATP 合酶结合，促进基本线粒体功能。就壁肽而言，我们 发现有益分子是含有短 AA 链的二糖胞肽，并且它们 进入肠细胞的线粒体以抑制氧化应激。引人注目的是，胞肽发挥了这一作用 通过与 ATP 合酶的多个亚基结合，从而稳定复合物并促进 它的活动。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 人类肠上皮细胞、来自疾病患者的成纤维细胞和接受抗生素治疗的小鼠 清楚地表明了胞肽在促进氧化磷酸化和抑制氧化磷酸化中的作用 哺乳动物细胞的氧化应激。未来几年，我们将继续扩大分析 有效的胞肽，以了解其结构特性及其在促进氧化磷酸化中的作用 不同哺乳动物组织及其在抑制疾病中线粒体功能障碍方面的潜在作用 细胞和小鼠。此类研究具有很高的医学意义，因为线粒体功能障碍众所周知 与多种人类疾病有关，包括主要的神经退行性疾病、心血管疾病、 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 线粒体稳态机制。使用 Seahorse 分析仪检查氧化呼吸 将极大地促进这些关于线粒体功能的拟议研究。

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.