靶向肠道菌群的丹参乙酸镁抗糖尿病肾病机制和代谢组学研究

Magnesium lithospermate B (MLB), although with extremely low bioavailability, showed significant activity in the treatment of diabetic nephropathy (DN) after oral administration, indicating that it is worthy of further exploring its mechanism of action. Recent research showed that gut microbiota dysbiosis deteriorated kidney injure, in terms of increase of endotoxin, loss of intestinal barrier integrity, disturbance of intestinal metabolites such as short chain fatty acids and uremic toxins. It comes to be an important aspect for targeting microbiota to investigate the mechanism of MLB on anti-DN efficacy. Based on our previous work, we found that MLB inhibited microbiota dysbiosis, as well as modified constituents of bile acids, a series of microbiota-related metabolites. In current project, anti-DN effect mechanism of MLB will be further studied. We will investigate whether MLB is capable of preventing microbiota dysbiosis and improving intestinal barrier integrity; explore what series of small molecular metabolites are varied by MLB treatment using metabolomics platform and identify the potential biomarkers; verify how key bacteria or metabolites contribute to MLB’s efficacy via fecal microbiota transplant or metabolite supplement operation; and illustrate how MLB influences the expression and activity of key metabolic enzymes by combined application of in vitro incubation technique and biochemical tools. The current project will further expound the relationship between gut microbiota and DN; establish theoretical basis for the oral application of MLB on DN.

丹参乙酸镁（MLB）口服显示良好的治疗糖尿病肾病活性，但其生物利用度极低，因此MLB的作用机制值得深入研究。最近研究发现，肠道菌在肾损伤过程中起到重要作用，因此靶向肠道菌群，解释MLB的抗糖尿病肾病作用机制成为一个新的研究方向。前期工作中，我们发现MLB在发挥药效时，能够改善肠道菌群紊乱，调节胆汁酸代谢。本项目拟对MLB靶向肠道菌的抗糖尿病肾病作用机制进行深入研究，包括探索其对菌群紊乱的调整和肠道屏障作用的改善，使用代谢组学技术总结代谢物的变化规律并寻找生物标志物，使用菌群移植或代谢物干预的方法确认MLB所调节的关键菌和代谢物在其药效发挥中的作用，使用菌群培养和生物化学技术相结合确认MLB对关键代谢酶的作用机制。通过本项目的实施，阐明MLB靶向肠道菌群发挥抗糖尿病肾病的作用机制，为将其开发成口服药物提供理论依据。

糖尿病肾病是糖尿病的严重并发症，是终末期肾病的主要病因。本项目验证了尽管生物利用度极低，口服丹参乙酸镁（MLB）对糖尿病肾病造成的肾损伤具有良好的保护作用。接着，对其靶向肠道菌群的作用机制进行了深入研究。结果表明，MLB能调节肠道菌群及其相关代谢产物紊乱，对糖尿病肾病造成的胆汁酸、短链脂肪酸和氨基酸的含量改变均有所回调。 此外，发现了MLB可降低血浆中硫酸对甲酚（PCS）、硫酸吲哚酚、硫酸苯酚等尿毒毒素水平。随后，阐明了MLB通过调节肠道PCS通路，逆转了DN小鼠血浆PCS水平的升高这一机制，监测了PCS的前体，包括酪氨酸、4-羟基苯乙酸和对甲苯酚的水平，结果表明MLB可通过抑制肠内4-羟基苯乙酸向对甲苯酚的转化来影响PCS的代谢。最后，进一步通过体外和体内实验来证实这一机制。综上所述，本项目阐明了MLB通过调节与PCS代谢相关的肠道菌群来改善糖尿病肾病的作用机制。此外，为靶向肠道菌群药物的机制研究提供了新思路，并为糖尿病肾病的治疗提供了新策略。