7-Chloroarctinone-b as a new selective PPARgamma antagonist potently blocks adipocyte differentiation.
OBJECTIVE
Peroxisome proliferator-activated receptor gamma (PPARgamma) is a therapeutic target for obesity, cancer and diabetes mellitus. In order to develop potent lead compounds for obesity treatment, we screened a natural product library for novel PPARgamma antagonists with inhibitory effects on adipocyte differentiation.


METHODS
Surface plasmon resonance (SPR) technology and cell-based transactivation assay were used to screen for PPARgamma antagonists. To investigate the antagonistic mechanism of the active compound, we measured its effect on PPARgamma/RXRalpha heterodimerization and PPARgamma co-activator recruitment using yeast two-hybrid assay, Gal4/UAS cell-based assay and SPR based assay. The 3T3-L1 cell differentiation assay was used to evaluate the effect of the active compound on adipocyte differentiation.


RESULTS
A new thiophene-acetylene type of natural product, 7-chloroarctinone-b (CAB), isolated from the roots of Rhaponticum uniflorum, was discovered as a novel PPARgamma antagonist capable of inhibiting rosiglitazone-induced PPARgamma transcriptional activity. SPR analysis suggested that CAB bound tightly to PPARgamma and considerably antagonized the potent PPARgamma agonist rosiglitazone-stimulated PPARgamma-LBD/RXRalpha-LBD binding. Gal4/UAS and yeast two-hybrid assays were used to evaluate the antagonistic activity of CAB on rosiglitazone-induced recruitment of the coactivator for PPARgamma. CAB could efficiently antagonize both hormone and rosiglitazone-induced adipocyte differentiation in cell culture.


CONCLUSIONS
CAB shows antagonistic activity to PPARgamma and can block the adipocyte differentiation, indicating it may be of potential use as a lead therapeutic compound for obesity.
Li
Yong-tao
YT
School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China.
Li
Li
L
Chen
Jing
J
Hu
Tian-cen
TC
Huang
Jin
J
Guo
Yue-wei
YW
Jiang
Hua-liang
HL
Shen
Xu
X
D041721:3T3-L1 Cells / Q000187:drug effects; D017667:Adipocytes / Q000187:drug effects*; D050156:Adipogenesis / Q000187:drug effects; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D019281:Dimerization; D006801:Humans; D051379:Mice; D047495:PPAR gamma / Q000037:antagonists & inhibitors*; D020349:Surface Plasmon Resonance; D013876:Thiophenes / Q000494:pharmacology*; D015533:Transcriptional Activation / Q000187:drug effects; D020798:Two-Hybrid System Techniques
C544871:7-chloroarctinone-b; D047495:PPAR gamma; D013876:Thiophenes
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