Michelotti Tainara Cristina, Lamothe Valérie, Jean-Alphonse Frédéric, Reiter Eric, Bonnet Muriel, Durand Guillaume
INRAE, Université Clermont Auvergne, VetAgro Sup, UMR Herbivores, Saint-Genès-Champanelle, France.
Feed and Food Department, Bordeaux Sciences Agro, Gradignan, France.
Front Cell Dev Biol. 2025 Aug 20;13:1645031. doi: 10.3389/fcell.2025.1645031. eCollection 2025.
Free fatty acids (FFAs) have been identified as ligands for members of the G protein-coupled receptor (GPCR) family, called free fatty acid receptors (FFARs). Among these receptors, there is a particular interest in the physiological roles of FFAR2 and its potential use as a therapeutic target for various health disorders. Despite great progress in other species, pharmacological properties of the bovine FFAR2 (bFFAR2) are not fully understood. The aim of the current study was to evaluate how a selection of FFAs (C2:0 to C8:0, and branched FFAs) activate and regulate bFFAR2 signaling.
We used HEK293A cells and BRET assays to measure Gαi/Gαq coupling and signaling, β-arrestin 2 recruitment, and receptor internalization/trafficking. SRE and NFAT-RE dependent transcription was assessed by luciferase reporter assay.
Results show that bFFAR2 presents a dual coupling to Gαi and Gαq and recruits β-arrestin 2 when stimulated with short and medium-chain FFAs up to eight carbons. Straight-chain FFAs with 4 to 7 carbons plus 3-methyl-butanoic acid showed the greatest potency to activate bFFAR2 upstream and downstream signaling, while C2:0, C3:0 and 2-methylpropanoic acid (2MP) were the least potent. 2MP exhibited minimal pharmacological activity towards β-arrestin 2, and although it induced receptor internalization, bFFAR2 trafficking to the early endosome was not observed. Overall, the number of carbons of straight-chain FFAs and methyl position of branched FFAs differentially regulates the activation of bFFAR2.
游离脂肪酸（FFA）已被确定为G蛋白偶联受体（GPCR）家族成员的配体，称为游离脂肪酸受体（FFAR）。在这些受体中，人们对FFAR2的生理作用及其作为各种健康疾病治疗靶点的潜在用途尤为感兴趣。尽管在其他物种中取得了很大进展，但牛FFAR2（bFFAR2）的药理学特性尚未完全了解。本研究的目的是评估一系列FFA（C2:0至C8:0以及支链FFA）如何激活和调节bFFAR2信号传导。
我们使用HEK293A细胞和BRET分析来测量Gαi/Gαq偶联和信号传导、β-抑制蛋白2募集以及受体内化/运输。通过荧光素酶报告基因分析评估SRE和NFAT-RE依赖性转录。
结果表明，bFFAR2与Gαi和Gαq呈现双重偶联，在用含八个碳的短链和中链FFA刺激时会募集β-抑制蛋白2。含4至7个碳的直链FFA加上3-甲基丁酸显示出激活bFFAR2上游和下游信号传导的最大效力，而C2:0、C3:0和2-甲基丙酸（2MP）效力最低。2MP对β-抑制蛋白2表现出最小的药理活性，尽管它诱导了受体内化，但未观察到bFFAR2转运至早期内体。总体而言，直链FFA的碳数和支链FFA的甲基位置对bFFAR2的激活有不同的调节作用。
