School of Pharmacy , ‡APC Microbiome Ireland , §School of Biochemistry and Cell Biology , ∥School of Microbiology , ⊥School of Medicine , University College Cork , Cork , Ireland.
Mol Pharm. 2018 Dec 3;15(12):5711-5727. doi: 10.1021/acs.molpharmaceut.8b00875. Epub 2018 Nov 16.
Pharmacokinetic research at the host-microbe interface has been primarily directed toward effects on drug metabolism, with fewer investigations considering the absorption process. We previously demonstrated that the transcriptional expression of genes encoding intestinal transporters involved in lipid translocation are altered in germ-free and conventionalized mice possessing distinct bile acid signatures. It was consequently hypothesized that microbial bile acid metabolism, which is the deconjugation and dehydroxylation of the bile acid steroid nucleus by gut bacteria, may impact upon drug transporter expression and/or activity and potentially alter drug disposition. Using a panel of three human intestinal cell lines (Caco-2, T84, and HT-29) that differ in basal transporter expression level, bile acid conjugation-, and hydroxylation-status was shown to influence the transcription of genes encoding several major influx and efflux transporter proteins. We further investigated if these effects on transporter mRNA would translate to altered drug disposition and activity. The results demonstrated that the conjugation and hydroxylation status of the bile acid steroid nucleus can influence the cellular response to multidrug resistance (MDR) substrates, a finding that did not directly correlate with directionality of gene or protein expression. In particular, we noted that the cytotoxicity of cyclosporine A was significantly augmented in the presence of the unconjugated bile acids deoxycholic acid (DCA) and chenodeoxycholic acid (CDCA) in P-gp positive cell lines, as compared to their taurine/glycine-conjugated counterparts, implicating P-gp in the molecular response. Overall this work identifies a novel mechanism by which gut microbial metabolites may influence drug accumulation and suggests a potential role for the microbial bile acid-deconjugating enzyme bile salt hydrolase (BSH) in ameliorating multidrug resistance through the generation of bile acid species with the capacity to access and inhibit P-gp ATPase. The physicochemical property of nonionization is suggested to underpin the preferential ability of unconjugated bile acids to attenuate the efflux of P-gp substrates and to sensitize tumorigenic cells to cytotoxic therapeutics in vitro. This work provides new impetus to investigate whether perturbation of the gut microbiota, and thereby the bile acid component of the intestinal metabolome, could alter drug pharmacokinetics in vivo. These findings may additionally contribute to the development of less toxic P-gp modulators, which could overcome MDR.
在宿主-微生物界面的药代动力学研究主要集中在药物代谢的影响上，而对吸收过程的研究较少。我们之前的研究表明，在具有不同胆汁酸特征的无菌和常规化小鼠中，参与脂质转运的肠道转运体的基因转录表达发生了改变。因此，假设微生物胆汁酸代谢（即肠道细菌对胆汁酸甾体核的去结合和去羟化）可能会影响药物转运体的表达和/或活性，并可能改变药物处置。使用一组三种人肠细胞系（Caco-2、T84 和 HT-29），它们在基础转运体表达水平上有所不同，显示出胆汁酸结合和羟化状态会影响编码几种主要流入和流出转运蛋白的基因的转录。我们进一步研究了这些对转运体 mRNA 的影响是否会转化为改变的药物处置和活性。结果表明，胆汁酸甾体核的结合和羟化状态可以影响多药耐药（MDR）底物的细胞反应，这一发现与基因或蛋白表达的方向性没有直接相关性。特别是，我们注意到，与牛磺酸/甘氨酸结合的对应物相比，在 P-糖蛋白阳性细胞系中，无结合胆汁酸脱氧胆酸（DCA）和鹅脱氧胆酸（CDCA）的存在显著增强了环孢素 A 的细胞毒性，表明 P-糖蛋白参与了分子反应。总的来说，这项工作确定了肠道微生物代谢物可能影响药物积累的新机制，并表明微生物胆汁酸去结合酶胆汁盐水解酶（BSH）通过生成具有穿透和抑制 P-糖蛋白 ATP 酶能力的胆汁酸种类，在改善多药耐药方面可能发挥作用。非离子化的物理化学性质被认为是未结合胆汁酸减弱 P-糖蛋白底物外排的优先能力，并使肿瘤细胞对体外细胞毒性治疗更敏感的基础。这项工作为研究肠道微生物群的扰动，从而改变肠道代谢组的胆汁酸成分是否会改变体内药物药代动力学提供了新的动力。这些发现可能有助于开发毒性更低的 P-糖蛋白调节剂，从而克服多药耐药性。
