人体肠道细菌产生结构相关的单甘油脂,具有对比的免疫功能
Ji-Sun Yoo1, Da-Jung Jung1, Byoungsook Goh1
1Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Boston, MA, USA.
Nature microbiology
|October 10, 2025
概括
肠道细菌产生免疫调节脂质. Bacteroides fragilis产生BfaGCs,而其他细菌如Enterococcus产生aGDGs,可以阻止NKT细胞激活,影响肠道微生物群.
科学领域:
- 微生物组研究 微生物组研究
- 免疫学 免疫学 免疫学
- 甘油脂的新陈代谢
背景情况:
- 肠共生体 Bacteroides fragilis 合成α-galactosylceramides (BfaGCs),对于调节结肠自然杀手T细胞至关重要.
- BfaGCs的精确合成途径以及它们在人类肠道细菌中产生的流行程度在很大程度上是未知的.
研究的目的:
- 为了阐明B. fragilis.中的脂生物合成途径.
- 识别其他能够产生类似免疫活性糖脂的肠道细菌.
- 研究这些细菌甘油脂在调节宿主免疫力,特别是NKT细胞反应中的功能性作用.
主要方法:
- 采用遗传和代谢分析来绘制B. fragilis.中脂生物合成途径的地图.
- 利用小鼠模型来评估在NKT细胞调节中的关键酶如α-galactosyltransferase (AgtT) 的体内功能.
- 分析了婴儿肠道基因组数据,以确定不同细菌物种和宿主年龄中参与糖脂合成的基因的分布和丰度.
主要成果:
- 确定了α-galactosyltransferase (AgtT) 作为对小鼠B. fragilis介导的NKT细胞调节的必要和足够的.
- 发现,虽然AgtT仅限于少数Bacteroidales物种,但像BgsB这样的结构同类物种广泛存在,特别是在Enterococcus中,产生α-glycosyldiacylglycerols (aGDGs).
- 证明aGDGs作为对抗性联结体,抑制BfaGC诱导的NKT细胞激活在体外和体内,其中B. fragilis主导婴儿肠道中的agcT丰度.
结论:
- 细菌甘油脂表现出不同的结构和免疫调节功能,BfaGCs和aGDGs在NKT细胞激活中发挥着截然不同的作用.
- 甘油脂产生细菌的流行和动态变化,如B. fragilis和Enterococcus,在早期人类肠道微生物群中具有重要意义.
- 这些发现揭示了肠道共生体,其代谢物和宿主免疫系统发育之间的复杂相互作用,突出了微生物甘油脂的重要性.
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