多氯联苯(PCBs)是与非酒精性脂肪肝(NAFLD)相关的持久性有机污染物。以前,我们证明了PCB混合物,Aroclor1260,加剧了NAFLD,反射毒性相关脂肪性肝炎,在饮食诱导的肥胖小鼠中,部分通过孕烷-异种生物受体(PXR)和组成型雄甾烷受体(CAR)激活。最近的研究还报道了PCB诱导的肠道微生物组变化,从而影响NAFLD。因此,本研究的目的是研究PCB对肠-肝轴的影响,并表征CAR和PXR在微生物组改变中的作用.C57Bl/6(野生型,WT),CAR和PXR敲除小鼠饲喂高脂肪饮食并暴露于Aroclor1260(20mg/kg,口服灌胃,12周)。盲肠样品的宏基因组学分析显示,无论暴露状态如何,CAR和/或PXR消融都会增加细菌α多样性。与WT相比,CAR和PXR消融还增加了细菌组成(β多样性);Aroclor1260仅在WT和CAR敲除中改变了β多样性。在WT和敲除组之间观察到不同分类水平的细菌丰度的不同变化;然而,Aroclor1260对每个基因型内的细菌丰度具有适度的影响。值得注意的是,两个敲除组显示放线菌和Verrucomicrobia丰度增加。尽管细菌多样性得到改善,然而,敲除组未能显示对PCB诱导的肝和肠毒性的保护,包括降低的回肠通透性标志物的mRNA水平(occludin,claudin3).总之,CAR和PXR消融显着改变了饮食诱导的肥胖中的肠道微生物组,而Aroclor1260损害了基因敲除小鼠的肠道完整性,多氯联苯和CAR之间的相互作用,肠-肝轴上的PXR。
Polychlorinated biphenyls (PCBs) are persistent organic pollutants associated with non-alcoholic fatty liver disease (NAFLD). Previously, we demonstrated that the PCB mixture, Aroclor1260, exacerbated NAFLD, reflective of toxicant-associated steatohepatitis, in diet-induced obese mice, in part through pregnane-xenobiotic receptor (PXR) and constitutive androstane receptor (CAR) activation. Recent studies have also reported PCB-induced changes in the gut microbiome that consequently impact NAFLD. Therefore, the objective of this study is to examine PCB effects on the gut-liver axis and characterize the role of CAR and PXR in microbiome alterations. C57Bl/6 (wildtype, WT), CAR and PXR knockout mice were fed a high fat diet and exposed to Aroclor1260 (20 mg/kg, oral gavage, 12 weeks). Metagenomics analysis of cecal samples revealed that CAR and/or PXR ablation increased bacterial alpha diversity regardless of exposure status. CAR and PXR ablation also increased bacterial composition (beta diversity) versus WT; Aroclor1260 altered beta diversity only in WT and CAR knockouts. Distinct changes in bacterial abundance at different taxonomic levels were observed between WT and knockout groups; however Aroclor1260 had modest effects on bacterial abundance within each genotype. Notably, both knockout groups displayed increased Actinobacteria and Verrucomicrobia abundance. In spite of improved bacterial diversity, the knockout groups however failed to show protection from PCB-induced hepato- and intestinal- toxicity including decreased mRNA levels of ileal permeability markers (occludin, claudin3). In summary, CAR and PXR ablation significantly altered gut microbiome in diet-induced obesity while Aroclor1260 compromised intestinal integrity in knockout mice, implicating interactions between PCBs and CAR, PXR on the gut-liver axis.