T0070907

T0070907 is a potent and selective PPARγ antagonist. With an apparent binding affinity of 1 nM, this compound covalently modifies PPARγ on cysteine 313 in helix 3 of human PPARγ2. It blocks PPARγ function in both cell-based reporter gene and adipocyte differentiation assays. Consistent with its role as an antagonist of PPARγ, this chemical blocks agonist-induced recruitment of coactivator-derived peptides to PPARγ in a homogeneous time-resolved fluorescence-based assay and promotes recruitment of the transcriptional corepressor NCoR to PPARγ in both glutathione S-transferase pull-down assays and a PPARγ/retinoid X receptor (RXR) α-dependent gel shift assay. Studies with mutant receptors suggest that it modulates the interaction of PPARγ with these cofactor proteins by affecting the conformation of helix 12 of the PPARγ ligand-binding domain. Interestingly, whereas the T0070907-induced NCoR recruitment to PPARγ/RXRα heterodimer can be almost completely reversed by the simultaneous treatment with RXRα agonist LGD1069, this compound treatment has only modest effects on LGD1069-induced coactivator recruitment to the PPARγ/RXRα heterodimer. [1] This chemical treatment inhibits proliferation, invasion and migration but does not significantly affect apoptosis. Molecular inhibition using a dominant negative (Δ462) receptor yields similar results. It also mediates a dose-dependent decrease in phosphorylation of PPARγ, and its ability to bind to DNA, and may directly affect mitogen-activated protein kinase signaling. [2]

Lipopolysaccharide preconditioning significantly attenuates the development of renal dysfunction, hepatocellular injury, and circulatory failure as well as the increase in the plasma levels of interleukin-1 [beta] caused by severe endotoxemia. This compound can attenuate all of these beneficial effects afforded by preconditioning with lipopolysaccharide [3]

• Essai de liaison au ligand

  Pour déterminer l'affinité de liaison de T0070907 aux PPARs, un essai de proximité par scintillation (SPA) est effectué avec les modifications suivantes. Une réaction de 90 μl contient du tampon SPA (10 mM KH₂PO₄, 10 mM KH₂PO₄, 2 mM EDTA, 50 mM NaCl, 1 mM dithiothréitol, 2 mM CHAPS, 10 % (v/v) glycérol, pH 7,1), 50 ng de GST-PPARγ (ou 150 ng de GST-PPARα, GST-PPARδ), 5 nM de radioligands marqués au ³H, et 5 μl de ce composé dans du Me₂SO. Après incubation pendant 1 h à température ambiante, 10 μl de billes SPA recouvertes de polylysine (à 20 mg/ml dans du tampon SPA) sont ajoutés, et le mélange est incubé pendant 1 h avant lecture dans Packard Topcount.

• Lignées cellulaires

  MCF-7 cells

• Concentrations

  20 μM and higher concentrations

• Temps d'incubation

  48 h

• Méthode

  MTS assay

• Modèles animaux

  Preconditioning is performed by administering a low dose (1 mg/kg) of Escherichia coli LPS (serotype 0.127:B8) intraperitoneally 24 hr before the induction of severe endotoxemia.

• Posologies

  1 mg/kg

• Administration

  intraperitoneally