Structural Basis for Small Molecule NDB (N-Benzyl-N-(3-(tert-butyl)-4-hydroxyphenyl)-2,6-dichloro-4-(dimethylamino) Benzamide) as a Selective Antagonist of Farnesoid X Receptor α (FXRα) in Stabilizing the Homodimerization of the Receptor
Structural Basis for Small Molecule NDB (N-Benzyl-N-(3-(tert-butyl)-4-hydroxyphenyl)-2,6-dichloro-4-(dimethylamino) Benzamide) as a Selective Antagonist of Farnesoid X Receptor α (FXRα) in Stabilizing the Homodimerization of the Receptor
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DOI：
10.1074/jbc.m114.630475
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发表时间：
2015-08-07
影响因子：
4.8
通讯作者：
Shen, Xu
中科院分区：
文献类型：
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作者：
Xu, Xing;Xu, Xin;Shen, Xu
法尼类X受体α(FXRα)作为一种胆汁酸感受器，在多种代谢过程中发挥着重要的作用，其拮抗剂最近在治疗代谢紊乱方面显示出特殊的兴趣，尽管其潜在的机制仍不清楚。在此，我们鉴定了小分子N-benzyl-N-(3-(tert-butyl)-4-hydroxyphenyl)-2，6-dichloro-4-(dimethylamino)苯甲酰胺(NDB)是人FXRα(hFXRα)的选择性拮抗剂，并分析了与NDB络合物中hFXRα配体结合域(hFXRα-LBD)的晶体结构。人们意外地发现，NDB通过形成hFXRα-LBD的同源二聚体来诱导螺旋11(H11)和螺旋12(H12，AF-2)的重排，这与单体状态下的活性构象完全不同，突变分析进一步支持了结合细节。此外，功能研究表明，NDB有效地拮抗GW4064刺激的FXR/RXR相互作用和FXRα靶基因的表达，包括小杂二聚体伙伴(SHP)和胆盐输出泵(BSEP)；同时，NDB给db/db小鼠有效地降低了磷酸烯醇式丙酮酸羧激酶(PEPCK)、葡萄糖6-磷酸酶(G6-Pase)、小杂二聚体伙伴和BSEP的基因表达。我们首次分析hFXRα-LBD.NDB的晶体结构将有助于阐明该受体的拮抗机制，NDB可能会发现其作为先导化合物在抗糖尿病研究中的潜力。
Farnesoid X receptor alpha (FXR alpha) as a bile acid sensor plays potent roles in multiple metabolic processes, and its antagonist has recently revealed special interests in the treatment of metabolic disorders, although the underlying mechanisms still remain unclear. Here, we identified that the small molecule N-benzyl-N-(3-(tert-butyl)-4-hydroxyphenyl)-2,6-dichloro-4-(dimethylamino) benzamide (NDB) functioned as a selective antagonist of human FXR alpha (hFXR alpha), and the crystal structure of hFXR alpha ligand binding domain (hFXR alpha-LBD) in complex with NDB was analyzed. It was unexpectedly discovered that NDB induced rearrangements of helix 11 (H11) and helix 12 (H12, AF-2) by forming a homodimer of hFXR alpha-LBD, totally different from the active conformation in monomer state, and the binding details were further supported by the mutation analysis. Moreover, functional studies demonstrated that NDB effectively antagonized the GW4064-stimulated FXR/RXR interaction and FXR alpha target gene expression in primary mouse hepatocytes, including the small heterodimer partner (SHP) and bile-salt export pump (BSEP); meanwhile, administration of NDBto db/db mice efficiently decreased the gene expressions of phosphoenolpyruvate carboxykinase (PEPCK), glucose 6-phosphatase (G6-pase), small heterodimer partner, and BSEP. It is expected that our first analyzed crystal structure of hFXR alpha-LBD.NDB will help expound the antagonistic mechanism of the receptor, and NDB may find its potential as a lead compound in anti-diabetes research.