肠道菌群介导溃疡性结肠炎大鼠肠CYP3A和P-糖蛋白的变化及机制  

Regulatory mechanisms of gut microbiota on intestinal CYP3A and P-glycoprotein in rats with dextran sulfate sodium-induced colitis

作　　者：高雪姣[1,2] 李婷[1,2] 魏斌[1,2] 严志祥[1,2] 燕茹[1,2] 

机构地区：[1]澳门大学中华医药研究院,中药质量研究国家重点实验室(澳门大学),中国澳门999078 [2]珠海澳大科技研究院,广东珠海519080

出　　处：《药学学报》2017年第1期34-43,共10页Acta Pharmaceutica Sinica

基　　金：国家自然科学基金资助项目(81473281);973基金资助项目(2009CB522707);澳门大学基金资助项目(MYRG2015-00220)

摘　　要：肠道细胞色素P450 3A(cytochrome P450 3A,CYP3A)和P-糖蛋白(P-glycoprotein,P-gp)是肠屏障的重要组成部分。炎症性肠病中肠CYP3A和P-gp下调伴随肠道菌群紊乱。但两者是否关联?机制如何?尚不清楚。本研究采用5%葡聚糖硫酸钠诱导大鼠溃疡性结肠炎(ulcerative colitis,UC),并对正常动物分别灌胃正常及UC动物粪便,发现粪便移植改变了受体动物肠道菌组成,而移植UC粪便组肠CYP3A2和P-gp mRNA的表达显著下调。外膜囊泡(outer-membrane vesicles,OMVs)是革兰阴性菌产生、进行群体行为及与环境通信的关键结构。不同处理组的OMVs均能下调人结肠腺癌细胞Caco-2中CYP3A4和P-gp的mRNA表达,而UC组以及UC粪便处理组的OMVs的抑制作用更强,且相对分子质量3~5万的OMVs组分的作用更显著。细胞经toll样受体4(toll like receptor 4,TLR4)抑制剂瑞沙托维处理或转染TLR4 si RNA能够阻断OMVs对CYP3A4和P-gp的下调。本研究证实,UC肠道菌部分通过分泌OMVs活化TLR4受体通路下调肠道CYP3A和P-gp表达。As important constituents of the first-line of host defense barrier, intestinal cytochrome P450 3A （CYP3A） and P-glycoprotein （P-gp） play important roles in disease pathogenesis as well as drug absorption and exposure. Clinical reports and experimental data revealed diminished intestinal CYP3A and P-gp expression accompanying with gut dysbiosis in inflammatory bowel disease. Yet whether gut dysbiosis is associated with the down-regulation of CYP3A and P-gp and the underlying mechanisms are unclear. In this study, daily administration of fresh feces from normal rats and rats with ulcerative colitis （UC） induced by dextran sulfate sodium to normal rats resulted in alterations of gut bacterial compositions. Intestinal CYP3A2 and P-gp were significantly down-regulated in rats receiving UC feces. Outer-membrane vesicles （OMVs） are nano-scale special buds of the outer membrane which are produced by Gram-negative bacteria and mediate diverse functions including interactions within bacterial communities and communications with host. Expressions of CYP3A4 and P-gp rnRNA were diminished in human epithelial colorectal adenocarcinoma cells （Caco-2） treated by OMVs from all different groups with OMVs from UC rats or rats receiving UC feces showing more significant effects.Moreover, the OMVs fractions within 30 000-50 000 Daltons from both normal and UC rats elicited more effects than fractions of other molecular weights. Treatment of Caco-2 cells with toll like receptor 4 （TLR4） inhibitor resatorvid （TAK-242） or TLR4 silence RNA （siRNA） blocked CYP3A4 and P-gp down-regulation induced by bacterial OMVs. Taken together, we proved in this study that gut microbiota can down-regulate intestinal CYP3A and P-gp partially through producing OMVs to activate the TLR4 signaling pathway.

关 键 词：肠道菌群失衡 粪菌移植 外膜囊泡 肠细胞色素P450 3A 肠P-糖蛋白 TOLL样受体4 

分 类 号：R963[医药卫生—微生物与生化药学]