CHEMBL5735879

Time-Resolved Fluorescence Resonance Energy Transfer (TR-FRET) Assay for Thyroid Hormone Receptor Agonist Screening: LanthaScreen TR-FRET Thyroid Receptor alpha Coactivator Assay kit (ThermoFisher) and LanthaScreen™ TR-FRET Thyroid Receptor beta Coactivator Assay kit (ThermoFisher) were used for agonist compound screening. Compounds in DMSO were diluted using ECHO Liquid Handler (Labcyte Inc.) into 384 plates in 10-point 3-fold series in duplicate (5 micro M final top concentration). Buffer C (ThermoFisher) was added to each well before the 4× mixture of fluorescein-SCR2-2 coactivator (200 nM final concentration), Terbium-labeled anti-GST antibody (2 nM final concentration), and TR alpha-LBD (0.4 nM final concentration) or TR beta-LBD (1.0 nM final concentration) was added. After 2 hour incubation at room temperature in dark, the TR-FRET signal was measured on an EnVision plate reader (PerkinElmer) with excitation at 340 nm and dual emission readout at 495 and 520 nm with the delay time of 100 micro second and the integration time of 200 micro second. The ratio of emission signal at 520 and at 495 was used to calculate EC50 using GraphPad Prism (GraphPad Software). In every batch of compound screening, T3 (L-3,3′,5-Triiodothyronine sodium salt, >95%) (Calbiochem) was used as reference compound. The EC50 of T3 measured were within 3-fold of the reference value provided by the assay kit manufacturer (ThermoFisher Scientific). The Z′ factors measured in every batch of screening using T3 as high percent effect (HPE) control and 0.5% DMSO as zero percent effect (ZPE) control were in the range of 0.5 to 0.8. Compounds' THR-beta selectivity values are derived from T3-selectivity normalized data.