Gut microbial metabolites sulfonolipids mediate high fat diet-induced intestinal inflammation

肠道微生物代谢物磺脂介导高脂肪饮食引起的肠道炎症

• 批准号: 10531456
• 负责人: Jie Li
• 金额: $ 17.93万
• 依托单位: UNIVERSITY OF SOUTH CAROLINA AT COLUMBIA
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-11 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10531456
• 关键词: Gut; microbial; metabolites; sulfonolipids; mediate

High fat diets (HFDs) alter both host inflammatory responses and gut microbial metabolites. While these metabolites have been hypothesized to mediate host intestinal inflammation, an existing gap is how to pinpoint the functional and responsible metabolites from an extremely complicated metabolites pool that contains numerous unknown chemicals. We seek to discover such functional metabolites and establish their role in modulating HFDs-induced intestinal inflammation. In our preliminary study, we first established a mouse model that displayed HFDsinduced intestinal inflammation. We next performed comparative metagenomic analysis of the gut microbiome collected from aforementioned mice, leading to identification of a genus, Alistipes, which was significantly increased during HFDs-induced inflammation. Alistipes is isolated primarily from clinical samples and shows emerging implications to inflammation, motivating us to investigate the potential links between Alistipes metabolites and the observed intestinal inflammation of our mouse model. Thus, we developed complementary metabolomics and genome mining approaches: metabolomic analysis of the mice fecal and serum samples directly displayed metabolic changes while genome mining revealed unique patterns of biosynthetic gene clusters that encode the metabolites of interests. Indeed, the cross-validation of these two approaches led to the discovery of a class of rare lipids, sulfonolipids (SLs) which were significantly increased in the HFDs-fed mice samples. The potential biosynthetic genes of these SLs were also accumulated in the HFDs-fed mice samples. The pure SLs were subsequently isolated, with the chemical structures elucidated by NMR. We then tested sulfobacin A, a major member of the isolated SLs, and it indeed induced macrophage RAW264.7 inflammatory responses by RT-PCR and ELISA analyses. All these preliminary data suggest that gut microbial metabolites SLs mediate HFDsinduced intestinal inflammation. Intriguingly, SLs structurally mimic human endogenous sphingolipids (SPs), with the latter known to mediate inflammation. In addition, a genus of gut microbiota, bacteroides, also produces SPs but not SLs. The bacteroidesderived SPs were recently shown to enter hosts’ metabolism and are critical for maintaining intestinal homeostasis and symbiosis. Taken together, this raises an interesting hypothesis that SLs may directly induce inflammation, but also may modulate inflammation by affecting intestinal homeostasis of SLs and SPs. Thus, we are now set up to unambiguously establish, both in vitro and in vivo, the role of SLs in mediating HFDsinduced intestinal inflammation, with an emphasis on the potential relationship between SLs and SPs. This goal will be achieved through completion of the following Specific Aims (SA). SA 1: Characterizing the HFDs-associated expression of microbial SLs, microbial SPs and host endogenous SPs. SA 2: Investigate the activities and relationship of SLs and SPs in mediating intestinal inflammation, using both invitro assays and in vivo germ-free mouse models. in vitro and in vivo, the role of SLs in mediating HFDs-induced intestinal inflammation, with an emphasis on the potential relationship between SLs and SPs. This goal will be achieved through completion of the following Specific Aims (SA).

高脂肪饮食（HFD）改变了宿主炎症反应和肠道微生物代谢产物。而这些 已经假设代谢产物介导宿主肠道注射，现有的差距是如何查明 来自极为复杂的代谢物池的功能和负责任的代谢产物，其中包含许多 未知化学物质。 我们试图发现这种功能代谢物并确定其在调节HFD诱导的 肠炎。在我们的初步研究中，我们首先建立了一个显示HFDSSTOUDS的鼠标模型 肠炎。接下来，我们对肠道微生物组进行了比较宏基因组分析 从依恋小鼠中收集，导致识别属，Alistipes，这显着增加了 在HFDS引起的炎症期间。 Alistipes与临床样品分离出来，并显示出新兴 对炎症的影响，激励我们调查Alistipes代谢物与 观察到的小鼠模型肠炎。那我们开发了完整的代谢组学， 基因组挖掘方法：直接显示的小鼠粪便和血清样品的代谢组分析 代谢变化，基因组开采揭示了编码的生物合成基因簇的独特模式 利益的代谢物。确实，这两种方法的交叉验证导致发现了一类稀有 脂质，硫脂（SL）在HFDS喂养的小鼠样品中显着增加。潜力 这些SLS的生物合成基因也积累在HFDS喂养的小鼠样品中。纯SL是 随后分离出来，由NMR阐明的化学结构。然后，我们测试了磺巴明A，一个主要 孤立的SLS成员，它确实诱导了RT-PCR的巨噬细胞RAW264.7炎症反应 和ELISA分析。所有这些初步数据表明，肠道微生物代谢物SLS介导HFDSS诱导的 肠炎。 有趣的是，SLS结构模仿人内源性鞘脂（SP），后者已知可以介导 另外，肠道菌群（杀菌剂）的属也会产生SPS，但不能产生SLS。细菌源性 最近显示，SPS进入宿主的代谢，对于维持肠内稳态至关重要 和共生。综上所述，这提出了一个有趣的假设，即SLS可能直接诱导 炎症，但也可能通过影响SLS和SPS的肠内稳态来调节炎症。 这是，我们现在已经设置为在体外和体内明确建立SLS在介导HFDSS诱导中的作用 肠道炎症，重点是SLS和SPS之间的潜在关系。这个目标 将通过完成以下特定目标（SA）来实现。 SA 1：表征微生物SL，微生物SP和宿主内源性SP的相关表达。 SA 2：使用Invitro调查SLS和SP在介导的肠道注射中的活动和关系 测定和无体内细菌小鼠模型。在体外和体内，SLS在介导HFD诱导的肠道中的作用 炎症，重点是SLS和SPS之间的潜在关系。将实现这个目标 通过完成以下特定目标（SA）。