作者:Brian D. Hudson、Elisabeth Christiansen、Hannah Murdoch、Laura Jenkins、Anders Højgaard Hansen、Ole Madsen、Trond Ulven、Graeme Milligan
DOI:10.1124/mol.114.093294
日期:2014.8
Analysis of the roles of the short chain fatty acid receptor, free fatty acid 3 receptor (FFA3), has been severely limited by the low potency of its endogenous ligands, the crossover of function of these on the closely related free fatty acid 2 receptor, and a dearth of FFA3-selective synthetic ligands. From a series of hexahydroquinolone-3-carboxamides, we demonstrate that 4-(furan-2-yl)-2-methyl-5-oxo- N -( o -tolyl)-1,4,5,6,7,8-hexahydroquinoline-3-carboxamide is a selective and moderately potent positive allosteric modular (PAM)-agonist of the FFA3 receptor. Modest chemical variations within this series resulted in compounds completely lacking activity, acting as FFA3 PAMs, or appearing to act as FFA3-negative allosteric modulators. However, the pharmacology of this series was further complicated in that certain analogs displaying overall antagonism of FFA3 function actually appeared to generate their effects via a combined positive allosteric binding cooperativity and negative allosteric effect on orthosteric ligand maximal signaling response. These studies show that various PAM-agonist and allosteric modulators of FFA3 can be identified and characterized. However, within the current chemical series, considerable care must be taken to define the pharmacological characteristics of specific compounds before useful predictions of their activity and their use in defining specific roles of FFA3 in either in vitro and in vivo settings can be made.
对短链脂肪酸受体自由脂肪酸3型受体(FFA3)功能的分析受到其内源性配体效力低、与相关性较高的自由脂肪酸2型受体功能重叠以及缺乏选择性FFA3合成配体的严重限制。从一系列六氢喹啉-3-羧酰胺中,我们证明了4-(呋喃-2-基)-2-甲基-5-氧代-N-(o-甲苯基)-1,4,5,6,7,8-六氢喹啉-3-羧酰胺是FFA3受体的选择性和中等效能的正变构调节剂(PAM)激动剂。在这一系列化合物中,适度的化学变化导致某些化合物完全缺乏活性、表现为FFA3 PAM或看似作为FFA3负变构调节剂。然而,进一步研究表明,某些表现出FFA3功能整体拮抗作用的类似物实际上似乎是通过正变构结合的协同作用和对正构配体最大信号反应的负变构效应来产生其作用。这些研究表明,可以识别和表征各种FFA3的PAM激动剂和变构调节剂。然而,在当前的化学系列中,必须非常小心地定义特定化合物的药理特性,才能对其活性和在体外及体内环境中定义FFA3的特定作用进行有用的预测。