Discovery of α-Aminoazaheterocycle-Methylglyoxal Adducts as a New Class of High-Affinity Inhibitors of Cystic Fibrosis Transmembrane Conductance Regulator Chloride Channels
作者:Christel Routaboul、Caroline Norez、Patricia Melin、Marie-Carmen Molina、Benjamin Boucherle、Florian Bossard、Sabrina Noel、Renaud Robert、Chantal Gauthier、Frédéric Becq、Jean-Luc Décout
DOI:10.1124/jpet.107.123307
日期:2007.9
The cystic fibrosis transmembrane conductance regulator (CFTR) represents the main Cl– channel in the apical membrane of epithelial cells for cAMP-dependent Cl– secretion. Here we report on the synthesis and screening of a small library of nontoxic α-aminoazaheterocycle-methylglyoxal adducts, inhibitors of wild-type (WT) CFTR and G551D-, G1349D-, and F508del-CFTR Cl– channels. In whole-cell patch-clamp experiments of Chinese hamster ovary (CHO) cells expressing WT-CFTR, we recorded rapid and reversible inhibition of forskolin-activated CFTR currents in the presence of the adducts 5a and 8a,b at 10 pM concentrations. Using iodide efflux experiments, we compared concentration-dependent inhibition of CFTR with glibenclamide (IC50 = 14.7 μM), 3-[(3-trifluoromethyl)phenyl]-5-[(4-carboxyphenyl-)methylene]-2-thioxo-4-thiazolidinone (CFTRinh-172) (IC50 = 1.2 μM), and α-aminoazaheterocycle-methylglyoxal adducts and identified compounds 5a (IC50 = 71 pM), 8a,b (IC50 = 2.5 nM), and 7a,b (IC50 = 3.4 nM) as the most potent inhibitors of WT-CFTR channels. Similar ranges of inhibition were also found when these compounds were evaluated on CFTR channels with the cystic fibrosis mutations F508del (in temperature-corrected human airway epithelial F508del/F508del CF15 cells)-, G551D-, and G1349D-CFTR (expressed in CHO and COS-7 cells). No effect of compound 5a was detected on the volume-regulated or calcium-regulated iodide efflux. Picomolar inhibition of WT-CFTR with adduct 5a was also found using a 6-methoxy- N -(3-sulfopropyl)-quinolinium fluorescent probe applied to the human tracheobronchial epithelial cell line 16HBE14o–. Finally, we found comparable inhibition by 5a or by CFTRinh-172 of forskolin-dependent short-circuit currents in mouse colon. To the best of our knowledge, these new nontoxic α-aminoazaheterocycle-methylglyoxal adducts represent the most potent compounds reported to inhibit CFTR chloride channels.
囊性纤维化跨膜导向调节因子(CFTR)是上皮细胞顶膜中主要的氯离子通道,负责cAMP依赖的氯离子分泌。我们在此报道了一小组无毒的α-氨基杂环甲基乙酮加合物的合成和筛选,这些化合物可抑制野生型(WT)CFTR以及G551D、G1349D和F508del-CFTR氯离子通道。在表达WT-CFTR的中国仓鼠卵巢(CHO)细胞的全细胞膜片钳实验中,我们记录到在10 pM浓度下,5a和8a,b加合物存在时,福斯克林激活的CFTR电流迅速且可逆地被抑制。通过碘离子外流实验,我们比较了CFTR的浓度依赖性抑制,使用了格列本脲(IC50 = 14.7 μM)、3-[(3-三氟甲基)苯基]-5-[(4-羧基苯基)亚甲基]-2-噻唑酮(CFTRinh-172)(IC50 = 1.2 μM)以及α-氨基杂环甲基乙酮加合物,确认化合物5a(IC50 = 71 pM)、8a,b(IC50 = 2.5 nM)和7a,b(IC50 = 3.4 nM)为WT-CFTR通道最有效的抑制剂。在对含有囊性纤维化突变F508del(温度修正的人类气道上皮F508del/F508del CF15细胞)、G551D和G1349D-CFTR(在CHO和COS-7细胞中表达)进行评估时,也发现了类似的抑制范围。未检测到化合物5a对体积调节或钙调节的碘离子外流的影响。使用6-甲氧基-N-(3-磺基丙基)喹啉荧光探针在16HBE14o–人类气管支气管上皮细胞系中,也发现了对WT-CFTR的皮摩尔级抑制。此外,我们发现5a或CFTRinh-172对小鼠结肠的福斯克林依赖性短路电流具有相似的抑制作用。根据我们所知,这些新的无毒的α-氨基杂环甲基乙酮加合物是目前已报道的对CFTR氯离子通道具有最强抑制作用的化合物。