Modulator activity at GAL4-tagged human RORgammat ligand binding domain expressed HEK293T cells by luciferase reporter gene assay relative to untreated control
ThermoFluor® Assay: Bar-coded assay plates are robotically loaded onto a thermostatically controlled PCR-type thermal block and then heated at a typical ramp-rate of 1 °C./min for all experiments. Fluorescence was measured by continuous illumination with UV light (Hamamatsu LC6) supplied via fiber optic and filtered through a band-pass filter (380-400 nm; >6 OD cutoff). Fluorescence emission of the entire 384-well plate was detected by measuring light intensity using a CCD camera (Sensys, Roper Scientific) filtered to detect 500±25 nm, resulting in simultaneous and independent readings of all 384 wells. Images were collected at each temperature, and the sum of the pixel intensity in a given area of the assay plate was recorded versus temperature. Reference wells contained RORγt without compounds, and the assay conditions were as follows: 0.065 mg/mL RORγt, 60 μM 1,8-ANS, 100 mM Hepes, pH 7.0, 10 mM NaCl, 2.5 mM GSH, 0.002% Tween-20. Project compounds were arranged in a pre-dosed mother plate (Greiner Bio-one) wherein compounds are serially diluted in 100% DMSO by 1:2 from a high concentration of 10 mM over 12 columns within a series (column 12 is a reference well containing DMSO, no compound). The compounds were robotically dispensed directly into assay plates (1×=46 nL) using a Hummingbird capillary liquid handling instrument (Digilab). Following compound dispense, protein and dye in buffer was added to achieve the final assay volume of 3 μL, followed by 1 μL of silicone oil.