High-Affinity Peroxisome Proliferator-Activated Receptor β/δ-Specific Ligands with Pure Antagonistic or Inverse Agonistic Properties

Abstract

Peroxisome proliferator-activated receptor ␤/␦ (PPAR␤/␦) is a ligand-regulated nuclear receptor with essential functions in metabolism and inflammation. We have synthesized a new derivative [methyl 3-(N-(4-(hexylamino)-2-methoxyphenyl)sulfamoyl)thiophene-2-carboxylate (ST247) structurally related to the published PPAR␤/␦ inhibitory ligand methyl 3-(N-(2-methoxy-4-(phenylamino)phenyl)sulfamoyl)thiophene-2-carboxylate (GSK0660). ST247 has a higher affinity to PPAR␤/␦ than GSK0660, and at equimolar concentrations, it more efficiently 1) induces the interaction with corepressors both in vitro and in vivo, 2) inhibits the agonist-induced transcriptional activity of PPAR␤/␦, and 3) downregulates basal level expression of the peroxisome proliferator responsive element-driven PPAR␤/␦ target gene ANGPTL4. Methyl 3-(N-(4-(tert-butylamino)-2-methoxyphenyl)sulfamoyl)thiophene-2-carboxylate (PT-S58), another high-affinity derivative from our series, also efficiently inhibits agonist-induced transcriptional activation, but in contrast to ST247, it does not enhance the interaction of PPAR␤/␦ with corepressors. PT-S58 rather prevents corepressor recruitment triggered by the inverse agonist ST247. These findings classify ST247 as an inverse agonist, whereas PT-S58 is the first pure PPAR␤/␦ antagonist described to date. It is noteworthy that ST247 and PT-S58 are also effective on PPREindependent functions of PPAR␤/␦: in monocytic cells, both ligands modulate expression of the activation marker CCL2 in the opposite direction as an established PPAR␤/␦ agonist. The possibility to differentially modulate specific functions of PPAR␤/␦ makes these novel compounds invaluable tools to advance our understanding of PPAR␤/␦ biology.

The Inverse Agonist DG172 Triggers a PPARβ/δ-Independent Myeloid Lineage Shift and Promotes GM-CSF/IL-4-Induced Dendritic Cell Differentiation

“…In some experiments IL-4 (5 or 200 ng/ml, as indicated) (PeproTech) and/or lipopolysaccharide (LPS; 100 ng/ml) (Sigma-Aldrich, Taufkirchen, Germany) were added, or M-CSF (Biomol, Hamburg, Germany; 20 ng/ml) was used instead of GM-CSF. Thioglycollate-elicited macrophages were obtained as described (Naruhn et al, 2011). NIH3T3 cells were cultured in Dulbecco's modified Eagle's medium, complemented with 10% fetal calf serum, 2 mM L-glutamine, 100 U/ml penicillin, and 100 mg/ml streptomycin.…”

“…Ligand binding was determined by TR-FRET in vitro using the Lanthascreen TR-FRET PPARb/d competitive binding assay (Life Technologies, Darmstadt, Germany) as described (Naruhn et al, 2011).…”

“…These include the irreversible inhibitor and partial PPARg agonist GSK3787 (Palkar et al, 2010;Shearer et al, 2010), the PPARb/dspecific GSK0660 (Shearer et al, 2008) and its improved derivative methyl 3-{N-[4-(hexylamino)-2-methoxyphenyl]sulfamoyl} thiophene-2-carboxylate (ST247) (Naruhn et al, 2011;Toth et al, 2012), and the stilbene (Z)-2-(2-bromophenyl)-3-{[4-(1-methylpiperazine)amino]phenyl}acrylonitrile (DG172) (Lieber et al, 2012). These ligands act as inverse agonists, as indicated by their inhibitory effect on the basal expression of PPARb/d target genes and an increased recruitment of transcriptional corepressors (Naruhn et al, 2011). DG172 is a PPARb/d-selective compound characterized by high affinity and potent repressive effects on PPARb/d target genes (Lieber et al, 2012).…”

Low-density lipoprotein docosahexaenoic acid nanoparticles induce ferroptotic cell death in hepatocellular carcinoma

“…The inhibitor ST247 may have been particularly effective at protecting the HepG2 cells from DHA and LDL-DHA cytotoxicity, because unlike GW6471 and GW9662 (traditional antagonists), it is a high affinity inverse agonist capable of inhibiting basal expression of PPARβ target genes as well as increasing recruitment of transcriptional corepressors. 31 While these findings provide some insight additional studies are needed to further elucidate the role of PPAR signaling in DHA and LDL-DHA’s anticancer cytotoxicity.…”

Synthesis, biological evaluation and molecular modeling studies of the PPARβ/δ antagonist CC618

“…Later, Müller and coworkers used GSK0660 (4) as a lead-compound for structure-activity studies leading to e.g. the analogue ST247 (5), with improved bioavailability and binding affinity [19,20]. The same research group recently developed the acrylonitrile compound DG172 (6) which exhibited potent PPARβ/δ antagonism and oral bioavailability [21].…”