肝细胞FXR对日本血吸虫感染小鼠肠道菌群的影响

Effect of hepatocyte FXR on gut microbiota mice infected with Schistosoma japonicum

目的分析肝细胞法尼醇X受体(farnesoid X receptor,FXR)特异性敲除对日本血吸虫感染小鼠肠道菌群的影响。方法6~8周龄野生型雄性C57BL/6J和肝细胞FXR特异性敲除小鼠(FXR-HKO)随机分为4组:野生型小鼠正常对照组(WT,n=5)、FXR-HKO小鼠正常对照组(FXR-HKO,n=6)、野生型小鼠日本血吸虫感染组(Sj-WT,n=6)、FXR-HKO小鼠日本血吸虫感染组(Sj-FXR-HKO,n=5)。其中,感染组每只小鼠感染(15±1)条日本血吸虫尾蚴,感染第5周处死小鼠,在无菌条件下收取小鼠结肠内容物,进行16S rDNA测序,比较各组之间的肠道菌群多样性和丰度差异。结果Beta多样性分析结果显示,Sj-WT组和Sj-FXR-HKO组小鼠的肠道菌群与正常小鼠肠道菌群有明显的分群。在门水平上,与正常对照组相比,Sj-WT组和Sj-FXR-HKO组小鼠肠道中拟杆菌门的丰度升高,厚壁菌门丰度降低,厚壁菌门与拟杆菌门丰度比值明显降低(均P<0.05)。在属水平上,与正常对照组相比,日本血吸虫感染后小鼠肠道中拟杆菌属的丰度明显升高(均P<0.05),Sj-FXR-HKO组拟杆菌属的丰度比Sj-WT组的升高更明显(P<0.05),其中Sj-WT组脱硫弧菌属、杜氏菌属、乳杆菌属的丰度显著降低(均P<0.05),Sj-FXR-HKO组瘤胃球菌科属、毛罗菌科、杜氏菌属、乳杆菌属的丰度明显降低(均P<0.05)。结论肝细胞FXR特异性敲除影响了日本血吸虫感染小鼠肠道菌群稳态,为后续进一步研究FXR-肠道菌群在血吸虫病中的作用及机制奠定了扎实的实验基础。

Objective To analyze the effect of farnesoid X receptor(FXR)specific knockout in hepatocytes on the gut microbiota of mice infected with Schistosoma japonicum(S.japonicum).Methods Male C57BL/6J and hepatocyte-specific FXR KO(FXR-HKO)mice,aged 6-8 weeks,were randomly divided into four groups:a wild-type normal control group(WT,n=5),a FXR-HKO normal control group(FXR-HKO,n=6),a wild-type infected group(Sj-WT,n=6),and a FXR-HKO infected group(Sj-FXR-HKO,n=5).Mice in the infected group were infected with(15±1)cercaria of S.japonicum,and sacrificed on week 5 after infection.The colon contents were collected under sterile conditions for analyzing the diversity and abundance of gut microbiota by 16S rDNA sequencing.Results According to Beta diversity analysis,there were apparently differences in the gut microbiota between the Sj-WT group and the Sj-FXR-HKO group.At the phylum level,compared with the WT group,the Sj-WT group and Sj-FXR-HKO group showed increases in the abundance of Bacteroides significantly and decreases in the abundance of Firmicutes,with a reduced abundance ratio of Firmicutes and Bacteroides(P<0.05).At the genus level,compared with the WT group,the abundance of Bacteroides significantly increased in the gut microbiota of mice infected with S.japonicum(P<0.05).The abundance of Bacteroides in the Sj-FXR-HKO group was higher than that in the Sj-WT group(P<0.05).The abundances of Desulfovibrio,Dubosiella and Lactobacillus significantly decreased in the Sj-WT group(P<0.05),while the abundances of uncultured_bacterium_f_Ruminococcaceae,Lachnospiraceae_NK4A136_group,Dubosiella and Lactobacillus significantly decreased in the Sj-FXR-HKO group(P<0.05).Conclusions FXR-specific knockout in hepatocyte affects the homeostasis of gut microbiota in mice infected with S.japonicum.These findings provide a solid experimental foundation for further investigating the role and mechanism of FXR-gut microbiota in schistosomiasis.