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）会改变宿主炎症反应和肠道微生物代谢物。 代谢物已被利用来介导宿主肠道炎症，现有的差距是如何查明 来自极其复杂的代谢物库的功能性和负责任的代谢物，其中包含大量 未知化学物质。 我们寻求发现此类功能性代谢物并确定它们在调节 HFD 诱导的中的作用 在我们的初步研究中，我们首先建立了一个显示 HFD 诱导的肠道炎症的小鼠模型。 接下来我们对肠道微生物组进行了比较宏基因组分析。 从上述小鼠中收集，从而鉴定出 Alistipes 属，该属的数量显着增加 在 HFD 引起的炎症期间，Alistipes 主要从临床样本中分离出来，并显示出正在出现的情况。 对炎症的影响，促使我们研究 Alitipes 代谢物与 因此，我们开发了补充代谢组学和 基因组挖掘方法：直接显示小鼠粪便和血清样本的代谢组学分析 代谢变化，而基因组挖掘揭示了编码生物合成基因簇的独特模式 事实上，这两种方法的交叉验证导致了一类罕见的代谢物的发现。 在喂食 HFD 的小鼠样本中，脂质、磺脂 (SL) 显着增加。 这些 SL 的生物合成基因也在 HFD 喂养的小鼠样本中积累。 随后分离，并通过 NMR 阐明了化学结构，然后我们测试了磺胺酸杆菌素 A，这是一种主要药物。 分离的 SL 成员，通过 RT-PCR 检测，它确实诱导了巨噬细胞 RAW264.7 炎症反应 所有这些初步数据表明肠道微生物代谢物 SL 介导 HFD 诱导。 肠道炎症。 有趣的是，SL 在结构上模仿人类内源性鞘脂 (SP)，已知后者可以介导 此外，肠道微生物群拟杆菌也产生 SP，但不产生 SL。 最近显示 SP 可以进入宿主的新陈代谢，对于维持肠道稳态至关重要 综合起来，这提出了一个有趣的假设，即 SL 可能直接诱导。 炎症，但也可能通过影响 SL 和 SP 的肠道稳态来调节炎症。 因此，我们现在准备在体外和体内明确地确定 SL 在介导 HFD 诱导的 肠道炎症，重点是 SL 和 SP 之间的潜在关系。 将通过完成以下具体目标 (SA) 来实现。 SA 1：表征微生物 SL、微生物 SP 和宿主内源 SP 的 HFD 相关表达。 SA 2：使用体外研究 SL 和 SP 在介导肠道炎症中的活性和关系 体外和体内无菌小鼠模型中 SL 在介导 HFD 诱导的肠道中的作用。 炎症，重点关注 SL 和 SP 之间的潜在关系，这一目标将会实现。 通过完成以下具体目标 (SA)。