Engineering microbiomes and their molecular determinants for production of butyrate and secondary bile acids from resistant starch

项目摘要/摘要--项目3 肠道微生物群产生丁酸是厌氧条件下微生物间相互作用的结果 食物网。鉴定微生物、环境条件和可发酵物的产脂组合 纤维将成为操纵骨髓移植患者微生物群的策略的基础，以提供治疗 丁酸盐的浓度。假设：1)从可发酵纤维中获得最大单链脂肪酸产量 需要一次纤维降解器、二次发酵罐和氢耗的组合 微生物。2)丁酸与总超临界脂肪酸的比率取决于 群落，这是由H2浓度，胆汁酸，pH和周转时间选择的 环境。方法：我们将使用来自健康人的微生物组的协变分析。 队列，以确定可发酵纤维、物理条件和微生物的产脂组合。我们 将通过组装已识别微生物的合成群落并测量 在不同条件下的体外生产丁酸，包括通过 具有水遗传营养的微生物。我们还将从粪便接种中选择共同进化的产酪菌群落 利用含有可发酵纤维的多通道介质作为主要碳和能源 消息来源。 一旦被输送到肠道上皮细胞，丁酸就可以被线粒体氧化。IT和Can 也通过过氧化物酶体增殖物激活受体(PPAR)刺激线粒体的生物发生 位于原子核上。理解产酪菌群与上皮细胞的相互作用 细胞将提供丁酸盐生产和生产之间的时间动态的机械解释。 宿主细胞的呼吸作用。假设：结肠的体内外呼吸和线粒体的生物发生 丁酸盐对上皮细胞有刺激作用。方法：呼吸和PPAR激活将是 在不同环境条件下暴露于丁酸盐的肠样组织中测量。用于活体估计 在呼吸方面，六周大的小鼠将被安排在西式饮食中添加可发酵的 纤维(S)或易接近的淀粉。胃肠道组织将每隔12周采集一次，并进行琥珀酸 将测量脱氢酶和细胞色素氧化酶的活性，以量化细胞的能力 呼吸。将跟踪无菌小鼠的细胞呼吸和粘膜O2浓度。 PPAR激动剂氨基水杨酸用于区分线粒体生物合成和丁酸 氧化。定居了合成微生物群落的小鼠将被用来测试 不同产脂能力的微生物群对呼吸作用的影响。

PROJECT SUMMARY/ABSTRACT – PROJECT 3 The production of butyrate from gut microbiomes results from interactions between microbes in anaerobic food webs. Identifying butyrogenic combinations of microbes, environmental conditions and fermentable fibers will underlie strategies for manipulating the microbiomes in BMT patients to provide therapeutic concentrations of butyrate. Hypotheses: 1) Maximal production of SCFAs from fermentable fibers requires the combination of a primary fiber degraders, secondary fermenters and hydrogen-consuming microbes. 2) The ratio of butyrate to total SCFAs is dependent on the taxonomic membership of communities, which is selected by the concentrations of H2, bile acids, pH and turnover time of the environment. Approaches: We will use covariation analysis of microbiomes from a healthy human cohort to identify butyrogenic combinations of fermentable fibers, physical conditions and microbes. We will test these predictions by assembling synthetic communities of the identified microbes and measuring butyrate production in vitro under various conditions, including the removal of hydrogen by hydrogenotrophic microbes. We will also select co-evolved butyrogenic communities from fecal inocula using multiple passages through media containing fermentable fiber as the primary carbon and energy source. Once transported into an intestinal epithelial cell, butyrate can be oxidized by mitochondria. It and can also stimulate mitochondrial biogenesis through Peroxisome Proliferator-Activated Receptors (PPARs) located on the nucleus. Understanding the interaction between a butyrogenic microbiome and epithelial cells will provide a mechanistic explanation of the temporal dynamics between butyrate production and host cell respiration. Hypothesis: In vitro and in vivo respiration and mitochondrial biogenesis in colonic epithelial cells will be stimulated by butyrate. Approaches: Respiration and PPAR activation will be measured in enteroids exposed to butyrate under varying environmental conditions. For in vivo estimates of respiration, mice at six weeks of age will be placed on a Western diet supplemented with a fermentable fiber(s) or accessible starch. GI tissues will be harvested at intervals up to 12 weeks and succinate dehydrogenase and cytochrome oxidase activities will be measured to quantify the capacity for cellular respiration. Cell respiration and mucosal O2 concentrations will be tracked in germ-free mice treated 5- aminosalicylic acid, a PPAR agonist, to distinguish between mitochondrial biosynthesis and butyrate oxidation. Mice colonized with synthetic communities of microbes to be used to test the impact of microbiomes of different butyrogenic capacity on respiration.