Interaction of the N-(3-Methylpyridin-2-yl)amide Derivatives of Flurbiprofen and Ibuprofen with FAAH: Enantiomeric Selectivity and Binding Mode
作者:Jessica Karlsson、Carmine M. Morgillo、Alessandro Deplano、Giovanni Smaldone、Emilia Pedone、F. Javier Luque、Mona Svensson、Ettore Novellino、Cenzo Congiu、Valentina Onnis、Bruno Catalanotti、Christopher J. Fowler
DOI:10.1371/journal.pone.0142711
日期:——
Background Combined fatty acid amide hydrolase (FAAH) and cyclooxygenase (COX) inhibition is a promising approach for pain-relief. The Flu-AM1 and Ibu-AM5 derivatives of flurbiprofen and ibuprofen retain similar COX-inhibitory properties and are more potent inhibitors of FAAH than the parent compounds. However, little is known as to the nature of their interaction with FAAH, or to the importance of their chirality. This has been explored here. Methodology/Principal Findings FAAH inhibitory activity was measured in rat brain homogenates and in lysates expressing either wild-type or FAAHT488A-mutated enzyme. Molecular modelling was undertaken using both docking and molecular dynamics. The (R)- and (S)-enantiomers of Flu-AM1 inhibited rat FAAH with similar potencies (IC50 values of 0.74 and 0.99 μM, respectively), whereas the (S)-enantiomer of Ibu-AM5 (IC50 0.59 μM) was more potent than the (R)-enantiomer (IC50 5.7 μM). Multiple inhibition experiments indicated that both (R)-Flu-AM1 and (S)-Ibu-AM5 inhibited FAAH in a manner mutually exclusive to carprofen. Computational studies indicated that the binding site for the Flu-AM1 and Ibu-AM5 enantiomers was located between the acyl chain binding channel and the membrane access channel, in a site overlapping the carprofen binding site, and showed a binding mode in line with that proposed for carprofen and other non-covalent ligands. The potency of (R)-Flu-AM1 was lower towards lysates expressing FAAH mutated at the proposed carprofen binding area than in lysates expressing wild-type FAAH. Conclusions/Significance The study provides kinetic and structural evidence that the enantiomers of Flu-AM1 and Ibu-AM5 bind in the substrate channel of FAAH. This information will be useful in aiding the design of novel dual-action FAAH: COX inhibitors.
背景脂肪酸酰胺水解酶(FAAH)和环氧化酶(COX)联合抑制是一种很有前景的止痛方法。氟比洛芬和布洛芬的 Flu-AM1 和 Ibu-AM5 衍生物具有类似的 COX 抑制特性,并且是比母体化合物更有效的脂肪酸酰胺水解酶抑制剂。然而,人们对它们与 FAAH 相互作用的性质及其手性的重要性知之甚少。本文对此进行了探讨。 方法/主要发现 在大鼠脑匀浆和表达野生型或 FAAHT488A 突变酶的裂解物中测量了 FAAH 的抑制活性。采用对接和分子动力学方法建立了分子模型。Flu-AM1 的(R)-和(S)-对映体对大鼠 FAAH 的抑制作用相似(IC50 值分别为 0.74 和 0.99 μM),而 Ibu-AM5 的(S)-对映体(IC50 0.59 μM)比(R)-对映体(IC50 5.7 μM)更强。多重抑制实验表明,(R)-Flu-AM1 和 (S)-Ibu-AM5 对 FAAH 的抑制方式与卡泊芬类互不相同。计算研究表明,Flu-AM1 和 Ibu-AM5 对映异构体的结合位点位于酰基链结合通道和膜通路通道之间,与卡泊芬碱的结合位点重叠,其结合模式与卡泊芬碱和其他非共价配体的结合模式一致。与表达野生型 FAAH 的裂解液相比,(R)-Flu-AM1 对表达在拟议的卡洛芬结合位点发生突变的 FAAH 的效力较低。 结论/意义 本研究提供了 Flu-AM1 和 Ibu-AM5 对映体在 FAAH 底物通道结合的动力学和结构证据。这些信息将有助于设计新型 FAAH:COX 双效抑制剂。