Department of Veterinary and Biomedical Sciences and the Center for Molecular Toxicology and Carcinogenesis, the Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Mol Pharmacol. 2010 Sep;78(3):419-30. doi: 10.1124/mol.110.065508. Epub 2010 Jun 1.
The availability of high-affinity agonists for peroxisome proliferator-activated receptor-beta/delta (PPARbeta/delta) has led to significant advances in our understanding of the functional role of PPARbeta/delta. In this study, a new PPARbeta/delta antagonist, 4-chloro-N-(2-{[5-trifluoromethyl)-2-pyridyl]sulfonyl}ethyl)benzamide (GSK3787), was characterized using in vivo and in vitro models. Orally administered GSK3787 caused antagonism of 4-[2-(3-fluoro-4-trifluoromethyl-phenyl)-4-methyl-thiazol-5-ylmethylsulfanyl]-2-methyl-phenoxy}-acetic acid (GW0742)-induced up-regulation of Angptl4 and Adrp mRNA expression in wild-type mouse colon but not in Pparbeta/delta-null mouse colon. Chromatin immunoprecipitation (ChIP) analysis indicates that this correlated with reduced promoter occupancy of PPARbeta/delta on the Angptl4 and Adrp genes. Reporter assays demonstrated antagonism of PPARbeta/delta activity and weak antagonism and agonism of PPARgamma activity but no effect on PPARalpha activity. Time-resolved fluorescence resonance energy transfer assays confirmed the ability of GSK3787 to modulate the association of both PPARbeta/delta and PPARgamma coregulator peptides in response to ligand activation, consistent with reporter assays. In vivo and in vitro analysis indicates that the efficacy of GSK3787 to modulate PPARgamma activity is markedly lower than the efficacy of GSK3787 to act as a PPARbeta/delta antagonist. GSK3787 antagonized GW0742-induced expression of Angptl4 in mouse fibroblasts, mouse keratinocytes, and human cancer cell lines. Cell proliferation was unchanged in response to either GW0742 or GSK3787 in human cancer cell lines. Results from these studies demonstrate that GSK3787 can antagonize PPARbeta/delta in vivo, thus providing a new strategy to delineate the functional role of a receptor with great potential as a therapeutic target for the treatment and prevention of disease.
高亲和力激动剂可用于过氧化物酶体增殖物激活受体-β/δ（PPARβ/δ），这使得我们对 PPARβ/δ的功能作用有了更深入的了解。在这项研究中，我们利用体内和体外模型对一种新型 PPARβ/δ拮抗剂 4-氯-N-（2-{[5-三氟甲基）-2-吡啶基]磺酰基}乙基）苯甲酰胺（GSK3787）进行了表征。口服给予 GSK3787 可拮抗 4-[2-（3-氟-4-三氟甲基-苯基）-4-甲基-噻唑-5-基甲基硫代]-2-甲基-苯氧基）-乙酸（GW0742）诱导的野生型小鼠结肠中 Angptl4 和 Adrp mRNA 表达的上调，但在 Pparβ/δ 缺失型小鼠结肠中则没有。染色质免疫沉淀（ChIP）分析表明，这与 PPARβ/δ在 Angptl4 和 Adrp 基因启动子上的占有率降低有关。报告基因检测表明，GSK3787 对 PPARβ/δ活性具有拮抗作用，对 PPARγ活性具有弱拮抗和激动作用，但对 PPARα活性没有影响。时间分辨荧光共振能量转移（TR-FRET）测定证实，GSK3787 能够调节配体激活后 PPARβ/δ和 PPARγ共激活肽的结合，这与报告基因检测结果一致。体内和体外分析表明，GSK3787 调节 PPARγ活性的效力明显低于 GSK3787 作为 PPARβ/δ拮抗剂的效力。GSK3787 拮抗 GW0742 诱导的小鼠成纤维细胞、小鼠角质细胞和人癌细胞系中 Angptl4 的表达。GW0742 或 GSK3787 对人癌细胞系的细胞增殖均无影响。这些研究结果表明，GSK3787 可在体内拮抗 PPARβ/δ，从而为阐明该受体的功能作用提供了一种新策略，该受体具有作为治疗和预防疾病的治疗靶点的巨大潜力。
