Proanthocyanidin metabolites produced by commensal gut microbes may promote metabolic resilience

项目概述：这个多学科的建议旨在定义原花青素（PAC），一个主要的类 葡萄多酚（GPs），改变肠道环境，促进与恢复力相关的生物特征 代谢综合征（MetS）和2型糖尿病（T2 D）。使用尿液，血液和肠道微生物群样本， 补充PAC的小鼠和补充GP的人类，将进行微生物群范围的关联研究。 用于将细菌菌株/种属的变化与微生物代谢产物的增加/减少相关联 （二）。PAC处理体外细菌和接种细菌分离株或定义的无菌小鼠 联合体将建立特定细菌和PAC衍生细菌之间的关系， 然后在哺乳动物细胞培养试验和高脂饮食（HFD）诱导的单- MetS/T2 D的相关无菌（GF）模型。PAC与代谢弹性有关;然而， 由于普遍缺乏吸收和不确定性，系统性保护机制仍然难以捉摸 关于分子靶点。PAC到达结肠，在那里它们被生物转化为具有更高生物利用度的MM; 然而，负责这些转化的特定细菌，所产生的MM的分子靶点， 它们在MetS/T2 D的临床前模型中的功效的验证仍有待研究。我们发现，GP 补充可诱导与以下相关的粘液溶解性肠道细菌嗜粘蛋白阿克曼氏菌中的水华： 降低血清脂多糖，减少肠道和全身炎症，增加紧密表达 连接蛋白闭合蛋白，改善葡萄糖代谢，减少HFD喂养小鼠的肥胖和体重增加。 增加了A。在胃旁路手术和二甲双胍治疗后观察到了嗜粘蛋白， 强调其在积极的代谢结果中的重要性。补充GP的小鼠还显示：1）减少 细菌群落丰富度; 2）属的改变与改善的肠道屏障完整性和乳酸 产酸; 3）降低血清细菌衍生的次级胆汁酸水平; 4）降低 与肠上皮相邻的粘液层在结肠中重新分布;和5）增加 血清脱氨基酪氨酸（DAT）水平，一种与免疫调节和恢复力相关的PAC衍生MM 对抗病毒引起的炎症最后，我们发现PAC足以增加肠道 丰富的A.嗜粘蛋白菌。我们的数据表明，PAC诱导的肠道环境改变促进了 新陈代谢恢复力为了建立因果关系，我们建议：1）将尿液/血液代谢物 使用在补充GP的人的纵向研究中收集的样品， 和PAC治疗的小鼠，同时监测HFD-和低- 脂肪饮食（LFD）喂养的鼠宿主; 2）进行体外和无菌小鼠研究以确认特异性 细菌分离物/聚生体对特定MM的作用; 3）在基于细胞的测定中研究PAC衍生的MM的生物活性 与葡萄糖代谢和HFD诱导的MetS/T2 D的B29-单相关GF小鼠模型相关。

Project Summary: This multidisciplinary proposal aims to define how proanthocyanidins (PACs), a major class of grape polyphenols (GPs), alter the intestinal milieu to promote a biological signature associated with resilience to metabolic syndrome (MetS) and type-2 diabetes (T2D). Using urine, blood, and gut microbiota samples from PAC-supplemented mice and GP-supplemented humans, microbiome-wide association studies will be performed to correlate changes in bacterial strains/species to increases/decreases in microbial metabolites (MMs). PAC treatment of bacteria in vitro and of germfree mice inoculated with bacterial isolates or defined consortia will establish relationships between specific commensal bacteria and PAC-derived MMs, which will then be tested for bioactivity in mammalian cell culture assays and a high-fat diet (HFD)-induced mono- associated germfree (GF) model of MetS/T2D. PACs are associated with metabolic resilience; however, mechanism(s) of systemic protection have remained elusive due to generally poor absorption and uncertainty about molecular targets. PACs reach the colon where they are biotransformed to MM with greater bioavailability; however, the specific bacteria responsible for these transformations, the molecular targets of resulting MM, and validation of their efficacy in preclinical models of MetS/T2D remain to be investigated. We observed that GP supplementation can induce a bloom in the mucolytic gut bacterium Akkermansia muciniphila in association with reduced serum lipopolysaccharide, less intestinal and systemic inflammation, increased expression of tight junction protein occludin, improved glucose metabolism, and less adiposity and weight gain in HFD-fed mice. Increased abundance of A. muciniphila has been observed after gastric bypass surgery and metformin treatment, underlining its importance in positive metabolic outcomes. GP-supplemented mice also showed: 1) decreased bacterial community richness; 2) alterations in genera consistent with improved gut barrier integrity and lactic acid-production; 3) decreased serum levels of bacterial-derived secondary bile acids; 4) decreased thickness of the mucus layer adjacent to the intestinal epithelium with redistribution of mucus in the colon; and 5) increased serum levels of desaminotyrosine (DAT), a PAC-derived MM associated with immune modulation and resilience against virus-induced inflammation. Finally, we showed that PACs, are sufficient to increase intestinal abundance of A. muciniphila. Our data suggest PAC-induced alterations of the intestinal milieu promote metabolic resilience. To establish cause-effect relationships we propose to: 1) correlate urine/blood metabolites with gut bacterial strains/species using samples collected in longitudinal studies of GP-supplemented humans and PAC-treated mice with concomitant monitoring of metabolic and histological phenotypes in HFD- and low- fat diet (LFD)-fed murine hosts; 2) perform in vitro and germfree mouse studies to confirm relationship of specific bacteria isolate/consortia to specific MM; 3) investigate bioactivities of PAC-derived MM in cell-based assays related to glucose metabolism and the B29-monoassociated GF mouse model of HFD-induced MetS/T2D.