Obstructive sleep apnea, the microbiome and cardiovascular disease

摘要 阻塞性睡眠呼吸暂停（OSA）是一种常见的疾病，影响超过10%的成年人和2-3%的人。 在美国的儿童。阻塞性睡眠呼吸暂停被认为是心血管疾病发生的独立危险因素 和肺部疾病，但其潜在的机制仍在很大程度上未知。特别是， 间歇性低氧和高碳酸血症（IHC，OSA的组成部分）在诱导或促进 心血管疾病仍然不清楚。测序技术和微生物及 代谢组学生物信息学揭示了肠道微生物组与 心血管疾病由于阻塞性睡眠呼吸暂停是这些疾病的一个关键危险因素，我们的初步研究 已经证明IHC改变了肠道微生物组的生态，并对代谢产生了强烈的影响，我们 假设IHC诱导肠道微生物组和微生物衍生代谢物的特异性改变， 这些变化可促进动脉粥样硬化。事实上，我们已经获得了强有力的候选微生物家族， 和代谢物，可以影响血管的完整性在IHC。例如，我们发现a）IHC 加速ApoE-/-小鼠中动脉粥样硬化的形成; B）IHC改变ApoE-/-小鼠的肠道微生物组生态学， 科，如疣微菌科、瘤胃球菌科和丹毒丝菌科;和 微生物衍生的代谢物（如胆汁盐（BA））。在当前应用中，我们关注这些 微生物群和代谢物候选物，以研究它们在动脉粥样硬化中的作用。首先，我们将分离出特定的 通过IHC处理改变的肠道微生物菌株，并确定这些特定微生物 使用无菌ApoE-/-小鼠体内心血管疾病发展中的一种或多种菌株， 在我们的实验室里创造和建立。其次，我们将描述主要胆汁酸受体的作用 (i.e., FXR和TGR 5）介导候选胆汁酸在IHC诱导的心血管疾病中的作用 使用ApoE-/-/FXR-/-和ApoE-/-/TGR 5-/-双敲除小鼠品系以及携带ApoE-/-/FXR-/-和ApoE-/-/TGR 5-/-的小鼠品系， ApoE-/-背景下FXR和TGR 5的细胞特异性条件性缺失。第三，我们将剖析 特异性IHC改变的胆汁酸作用的潜在机制（即，TβMCA和UDCA）诱导的 使用来源于ApoE-/-小鼠的原代细胞培养物体外巨噬细胞泡沫细胞形成 /FXR-/-和ApoE-/-/TGR 5-/-双缺失。该项目将描述新的机制，调节OSA- 诱导的心血管疾病，并提供潜在的新的目标和战略，以改善治疗或 预防疾病。

ABSTRACT Obstructive sleep apnea (OSA) is a common condition affecting >10% of the adult population and 2-3% of children in the USA. OSA is considered as an independent risk factor for the development of cardiovascular and lung disorders but the underlying mechanisms are still largely unknown. In particular, the role of intermittent hypoxia and hypercapnia (IHC, the integral components of OSA) in inducing or promoting cardiovascular conditions remains obscure. Recent advances in sequencing technology and microbial and metabolomic bioinformatics have shed light on an important relation between the gut microbiome and cardiovascular diseases. Since OSA is a critical risk factor for these disorders, and our preliminary studies have demonstrated that IHC alters the ecology of gut microbiome and have a strong impact on metabolism, we hypothesize that IHC induces specific alterations in the gut microbiome and microbial-derived metabolites, and these changes causally promote atherosclerosis. Indeed, we have obtained strong candidate microbial families and metabolites that can affect vascular integrity under IHC. For example, we have found that a) IHC accelerates the formation of atherosclerosis in ApoE-/- mice; b) IHC changes the gut microbiome ecology of families such as Verrucomicrobiaceae, Ruminococcaceae and Erysipelotrichaceae; and c) IHC alters microbial-derived metabolites (such as bile salts (BAs)). In the current application, we focus on these microbiota and metabolite candidates to investigate their role in atherosclerosis. First, we will isolate specific gut microbial strains that were altered by IHC treatment and determine the role of these specific microbial strain(s) in the development of cardiovascular disease in vivo using germ-free ApoE-/- mice that were currently created and established in our laboratory. Second, we will delineate the role of the major bile acid receptors (i.e., FXR and TGR5) in mediating the effect of candidate bile acids in IHC-induced cardiovascular disease in vivo using ApoE-/-/FXR-/- and ApoE-/-/TGR5-/- double knockout mice strains as well as the mice strains carrying cell specific conditional deletion of FXR and TGR5 on ApoE-/- background. And third, we will dissect the mechanisms underlying the role of specific IHC-altered bile acids (i.e., TβMCA and UDCA) in IHC-induced macrophage foam cell formation in vitro using primary cell cultures that are derived from mice with ApoE-/- /FXR-/- and ApoE-/-/TGR5-/- double deletion. This project will delineate novel mechanisms regulating OSA- induced cardiovascular disease and provide potential novel targets and strategies to improve treatment or prevent disease.