Interactions of dietary polyphenols, gut microbiota and intestinal epithelium

 描述（由申请人提供）：该多学科提案旨在提供膳食多酚如何赋予对慢性疾病（如代谢综合征（MetS）和2型糖尿病（T2 D））的适应力的机制见解。细菌细胞生物学结合元组学方法将首先用于评估多酚对微生物活力和代谢活性的急性影响，同时监测肠上皮细胞（IE）的急性变化。然后将小鼠肠道类器官用于区分多酚和生物转化/微生物代谢物对IE的影响，然后在无菌小鼠中进行肠道接种研究，以进一步确定影响能量代谢的因果关系。食用富含多酚的食物与降低慢性疾病的风险有关，但多酚提供的全身保护机制仍然难以捉摸，这是由于多酚吸收普遍较差以及其分子靶点的不确定性。多酚在肠道中积累，在那里它们可以被肠道微生物群生物转化为具有更高生物利用度的更简单的酚类化合物;然而，循环代谢物的水平和生物活性可能不足以解释其药理作用。我们观察到，葡萄多酚（GP）可以改变肠道微生物群生态，并减少高脂肪饮食（HFD）喂养的MetS/T2 D小鼠模型中的肠道和全身炎症，并改善葡萄糖代谢。与喂食HFD的对照组相比，喂食补充有GP的等热量HFD的C57 BL/6 J小鼠在消耗等量食物的同时具有更少的全身炎症、体重增加、肥胖和葡萄糖耐受不良。喂食补充有GP的HFD的小鼠的肠组织具有：1）较低水平的炎性介质，2）较高的闭合蛋白表达，表明屏障完整性改善; 3）增加的Fiaf表达，表明外周组织中脂肪沉积较少;和4）较高的胰高血糖素原表达，其分别是促进胰岛素产生/分泌和维持肠屏障完整性的GLP-1和GLP-2蛋白的前体。这些观察结果与嗜粘蛋白阿克曼菌（Akkermansia muciniphila）的急剧增加相关，嗜粘蛋白阿克曼菌是一种栖息在覆盖IE的粘液层中的微生物。增加了A。在胃旁路手术和二甲双胍治疗后观察到嗜粘蛋白，强调了其在积极代谢结果中的重要性。这些数据表明了为什么膳食多酚提供对MetS/T2 D的弹性;然而，由于GP由肠道微生物群代谢，因此仍有待确定是否完整的多酚或生物转化的代谢物介导A中的水华。嗜粘蛋白和肠道基因表达的变化。我们建议：1）确定微生物群和IE对GP的急性反应，并评估GP或其生物转化的代谢产物是否增加A。2）解偶联GP和生物转化的/微生物代谢物对IE的影响，使用离体培养的鼠肠道类器官，然后在无菌（GF）小鼠中进行肠道接种研究，以测试它们对常规（CONV）肥胖小鼠的多酚暴露微生物群的炎症和代谢反应。

 DESCRIPTION (provided by applicant): This multidisciplinary proposal aims to provide mechanistic insight into how dietary polyphenols confer resilience to chronic disease, such as metabolic syndrome (MetS) and type-2 diabetes (T2D). Bacterial cell biology combined with meta-omics approaches will first be used to assess acute effects of polyphenols on microbial viability and metabolic activity while in parallel monitoring acute changes in intestinal epitheliu (IE). Murine gut organoids will then be used to differentiate effects of polyphenols and biotransformed/microbial metabolites on IE followed by gut inoculation studies in germ-free mice to further define cause-effect relationships influencing energy metabolism. Consumption of polyphenol-rich foods is associated with reduced risk of chronic disease, but mechanism(s) of systemic protection offered by polyphenols have remained elusive due to generally poor polyphenol absorption and uncertainty about their molecular targets. Polyphenols accumulate in the intestine where they can be biotransformed by gut microbiota into simpler phenolic compounds with higher bioavailability; however, the levels and bioactivities of circulating metabolites may not be sufficient to explain their pharmacological effects. We observed that grape polyphenols (GP) can alter gut microbiota ecology and reduce intestinal and systemic inflammation in a high fat diet (HFD)-fed mouse model of MetS/T2D in association with improved glucose metabolism. Compared to HFD-fed controls, C57BL/6J mice fed isocaloric HFD supplemented with GP had less systemic inflammation, weight gain, adiposity, and glucose intolerance while consuming an equivalent amount of food. Intestinal tissues of mice fed GP- supplemented HFD had: 1) lower levels of inflammatory mediators, 2) higher occludin expression indicating improved barrier integrity; 3) increased Fiaf expression indicating less fat deposition in peripheral tissues; and 4) higher proglucagon expression, a precursor of GLP-1 and GLP-2 proteins that promote insulin production/secretion and maintain gut barrier integrity, respectively. These observations correlated with a dramatic increase in Akkermansia muciniphila, a microbe inhabiting the mucus layer covering the IE. Increased abundance of A. muciniphila was observed after gastric bypass surgery and metformin treatment, underlining its importance in positive metabolic outcomes. These data suggest why dietary polyphenols provide resilience against MetS/T2D; however, because GP are metabolized by gut microbiota it remains to be determined whether intact polyphenols or biotransformed metabolites mediate the bloom in A. muciniphila and intestinal gene expression changes. We propose to: 1) Determine the acute response of the microbiota and IE to GP and assess whether GP or their biotransformed metabolites increase A. muciniphila growth and 2) Uncouple the effects of GP and biotransformed /microbial metabolites on the IE using ex vivo cultured murine gut organoids followed by gut inoculation studies in germ-free (GF) mice to test their inflammatory and metabolic response to polyphenol- exposed microbiota of conventional (CONV) obese mice.