Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, Germany (B.A.K., U.M.Z.); University of Tübingen, Tübingen, Germany (B.A.K., U.M.Z.); Collaborations in Chemistry, Fuquay-Varina, North Carolina (S.E.); Department of Pharmaceutical Sciences, University of Maryland, Baltimore, Maryland (S.E.); Department of Pharmacology, Rutgers University-Robert Wood Johnson Medical School, Piscataway, New Jersey (S.E.); Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina (S.E.); Molecular and Clinical Pharmacy, Friedrich-Alexander University, Erlangen-Nuremberg, Germany (K.L.); Department of Surgery, Grosshadern Hospital, Ludwig-Maximilians University, Munich, Germany (W.E.T.); and Institute of Pharmacology and Toxicology, Interfaculty Centre for Pharmacogenomics and Drug Research, University of Tübingen, Tübingen, Germany (C.H.).
J Pharmacol Exp Ther. 2014 Mar;348(3):393-400. doi: 10.1124/jpet.113.209916. Epub 2013 Nov 20.
The acylated phloroglucinol, hyperforin, the main active ingredient of St. John's Wort, exerts antidepressant properties via indirect inhibition of serotonin reuptake by selectively activating the canonical transient receptor potential channel 6 (TRPC6). Hyperforin treatment can lead to drug-drug interactions due to potent activation of the nuclear receptor PXR (NR1I2), a key transcriptional regulator of genes involved in drug metabolism and transport. It was previously shown that synthetic acylated phloroglucinol derivatives activate TRPC6 with similar potency as hyperforin. However, their interaction potential with PXR remained unknown. Here we investigated five synthetic TRPC6-activating phloroglucinol derivatives and four TRPC6-nonactivating compounds compared with hyperforin and rifampicin for their potential to activate PXR in silico and in vitro. Computational PXR pharmacophore modeling did not indicate potent agonist or antagonist interactions for the TRPC6-activating derivatives, whereas one of them was suggested by docking studies to show both agonist and antagonist interactions. Hyperforin and rifampicin treatment of HepG2 cells cotransfected with human PXR expression vector and a CYP3A4 promoter-reporter construct resulted in potent PXR-dependent induction, whereas all TRPC6-activating compounds failed to show any PXR activation or to antagonize rifampicin-mediated CYP3A4 promoter induction. Hyperforin and rifampicin treatment of primary human hepatocytes resulted in highly correlated induction of PXR target genes, whereas treatment with the phloroglucinol derivatives elicited moderate gene expression changes that were only weakly correlated with those of rifampicin and hyperforin treatment. These results show that TRPC6-activating phloroglucinols do not activate PXR and should therefore be promising new candidates for further drug development.
酰化间苯三酚，贯叶金丝桃素，贯叶连翘的主要活性成分，通过间接抑制 5-羟色胺再摄取，选择性激活经典瞬时受体电位通道 6（TRPC6）发挥抗抑郁作用。贯叶金丝桃素治疗可由于核受体 PXR（NR1I2）的有效激活而导致药物相互作用，PXR 是参与药物代谢和转运的基因的关键转录调节剂。先前的研究表明，合成酰化间苯三酚衍生物通过与贯叶金丝桃素相似的效力激活 TRPC6。然而，它们与 PXR 的相互作用潜力仍然未知。在这里，我们研究了五个合成的激活 TRPC6 的间苯三酚衍生物和四个非激活 TRPC6 的化合物，与贯叶金丝桃素和利福平相比，研究它们在体内和体外激活 PXR 的潜力。计算的 PXR 药效团建模表明，对于激活 TRPC6 的衍生物，没有显示出强效激动剂或拮抗剂相互作用，而其中一种通过对接研究表明具有激动剂和拮抗剂相互作用。贯叶金丝桃素和利福平处理共转染人 PXR 表达载体和 CYP3A4 启动子报告构建体的 HepG2 细胞导致强烈的 PXR 依赖性诱导，而所有激活 TRPC6 的化合物均未显示出任何 PXR 激活作用，也不能拮抗利福平介导的 CYP3A4 启动子诱导。贯叶金丝桃素和利福平处理原代人肝细胞导致 PXR 靶基因的高度相关诱导，而间苯三酚衍生物的处理仅引起中度基因表达变化，与利福平和贯叶金丝桃素处理的变化相关性较弱。这些结果表明，激活 TRPC6 的间苯三酚衍生物不会激活 PXR，因此应该是进一步药物开发的有希望的新候选物。
