Cardiovascular disease, metabolic syndrome, microbes and metabolites in FHS

心脏代谢性疾病影响着全世界数以百万计的人，有许多潜在的风险因素。组成肠道微生物组的共生微生物与许多此类疾病的进展和发病有关，包括2型糖尿病、肥胖症和动脉粥样硬化。肠道微生物具有广泛的新陈代谢能力，使它们能够产生或修改影响疾病风险的分子。近100年来，肠道微生物区系的成员已知将胆固醇转化为难以吸收的代谢物辅前列醇，但负责这一代谢的微生物基因尚不清楚。在最近的工作中，我们分析了成对的肠道代谢组和代谢组学数据，以确定一组在体外表达时代谢胆固醇的新的胆固醇脱氢酶。利用弗雷明翰心脏研究(FHS)的临床和元基因组数据，我们观察到微生物群编码这些胆固醇脱氢酶的受试者血清胆固醇较低。我们最初描述的胆固醇脱氢酶将胆固醇转化为胆固酮，将辅前列酮转化为辅前列醇，自那以后，我们已经确定了将胆固酮转化为辅前列酮的中间酶。在这项提案中，我们将从功能上描述肠道中固醇的代谢，并确定这一过程对心脏代谢性疾病的影响。在目标1中，我们将通过收集和分析来自Gen3/Omni2 FHS队列的粪便和血清样本的临床变量来确定宿主-微生物相互作用的决定因素。我们将生成耦合的粪便和血清代谢组学和元基因组学数据集，执行培养组学以组装微生物菌株文库，并从临床数据中识别宿主暴露。然后，我们将利用这些数据来识别和优先处理与心血管疾病相关的微生物衍生或修饰的循环代谢物，以进行进一步的机制研究。在目标2中，我们将把生物信息学与微生物学和生物化学结合起来，有针对性地识别改变甾醇结构的酶/蛋白质。这项工作将使我们能够探索肠道微生物类固醇代谢酶及其底物的多样性，以确定特定的微生物和具有修饰胆固醇能力的基因。采用系统水平的方法，我们将在小鼠中定植胆固醇代谢微生物群落，以确定微生物代谢如何调节血清胆固醇和心血管疾病的核心途径。在目标3中，我们将从功能上将微生物组酶活性与甾醇代谢和代谢性疾病联系起来。我们将使用基于细胞的转录和蛋白质组分析来询问微生物修饰的类固醇对上皮细胞中局部类固醇感觉通路的影响，并测量循环中的类固醇代谢物对人类免疫细胞的影响。

Cardiometabolic diseases affect millions of people worldwide and have numerous underlying risk factors. Commensal microbes that comprise the intestinal microbiome are implicated in the progression and onset of many of these diseases, including type 2 diabetes, obesity, and atherosclerosis. Gut microbes have extensive metabolic capabilities, allowing them to produce or modify molecules that influence disease risk. Members of the gut microbiota have been known to convert cholesterol into the poorly absorbable metabolite coprostanol for almost 100 years, however the microbial genes responsible for this metabolism were not known. In recent work, we analyzed paired gut metagenomic and metabolomic data to identify a novel group of cholesterol dehydrogenases that metabolize cholesterol when expressed in vitro. Using clinical and metagenomic data from the Framingham Heart Study (FHS), we observed lower serum cholesterol in subjects whose microbiomes encode these cholesterol dehydrogenases. The cholesterol dehydrogenases we originally described convert cholesterol to cholestenone and coprostanone to coprostanol, and we have since identified the intermediate enzyme that converts cholestenone to coprostanone. In this proposal, we will functionally characterize metabolism of sterols in the gut and determine the impact of this process on cardiometabolic disease. In Aim 1, we will identify determinants of host-microbe interactions by collecting and analyzing clinical variables with stool and serum samples from the Gen3/Omni2 FHS cohorts. We will generate coupled stool and serum metabolomics and metagenomics datasets, perform culturomics to assemble a microbial strain library, and identify host exposomes from clinical data. We will then utilize these data to identify and prioritize microbially- derived or modified circulating metabolites associated with CVD for further mechanistic investigations. In Aim 2, We will couple bioinformatics with microbiology and biochemistry for targeted identification of enzymes/proteins that alter sterol structures. This effort will allow us to probe the diversity of gut microbial sterol metabolizing enzymes and their substrates in order to determine specific microbes and genes with the capacity to modify cholesterol. Taking a systems-level approach, we will colonize mice with cholesterol-metabolizing microbial communities to determine how microbial metabolism modulates serum cholesterol and pathways central to cardiovascular disease. In Aim 3, we will functionally link microbiome enzyme activity to sterol metabolism and metabolic disease. We will employ cell-based transcriptional and proteomic assays to interrogate the effects of microbially-modified sterols on local sterol sensing pathways in epithelial cells and measure the effects of circulating sterol metabolites on human immune cells.