| Assay Method Information | |
| | IRAK4 Monocyte TNFalpha Cell Based Assay |
| Description: | Cryopreserved human monocytes (Stem Cell Technologies) were thawed, diluted in RPMI with GlutaMAX (Gibco 200 mM L-alanyl-L-glutamine) (10 mM HEPES, 1× Pen-Strep, 55 μM -mercaptoethanol, 1 mM Sodium pyruvate) media containing 10% FBS to 0.125×106 cells/ml and recovered at 37° C. for 2 hours. The cell suspension was then plated at a density of 5,000 cells/well onto black 384 well Greiner clear bottom plates. Plates were pre-spotted with test compounds and serially diluted in DMSO where 200 nL/well were delivered using the Echo 550 acoustic liquid dispenser (Labcyte ) for a final DMSO concentration of 0.5%. Plated cells were treated with compound for 1 hour at 37° C. Cells were then stimulated with 50 pg/ml of LPS (Sigma) excluding outside columns of plate used for unstimulated cell control wells. Cells were incubated for an additional 4 hours at 37° C. Cells were then spun out of the media and 5 μl of sample were taken and analyzed for total TNFα content using the TR-FRET Human TNFα detection system (CisBio). This system utilizes two labeled antibodies (cryptate and XL665) that bind to two different epitopes of the TNFα molecule and produce FRET signal proportional to the concentration of TNFα in the sample. Detection antibodies are mixed 50:50 and 5 μL were dispensed into each well. Plates were covered with clear seals and incubated at room temp overnight. The following morning plates were read using an Envision 2103 Multilabeled reader (PerkinElmer) with excitation/emission/FRET emission at 340 nm/615 nm/665 nm, respectively. Fluorescence intensities at 615 nm and 665 nm emission wavelengths were expressed as a ratio (665 nm/615 nm). Percent of control was calculated as follows:% Control=100×(RatioSample−Ratio0% stimulation)/(Ratio100% Stimulation−Ratio0% Stimulation)where unstimulated cells (0% stimulation) were the negative control and stimulated cells (100% stimulation) were used as the positive control.IRAK4 Biochemical Assay Procedure:IRAK4 enzyme (Carna Biosciences, Chuo-ku, Kobe, Japan) activity was measured by detecting phosphorylated peptide substrate formation using an antibody against the phosphorylated peptide substrate. This is a time-resolved fluorescence resonance energy transfer (TR-FRET) immunoassay, based on the STK1 KinEASE Assay (Cisbio, Bedford, Mass.). The assay was designed as a simple two-step, endpoint assay (a 5 μl enzyme reaction followed by 5 μl stop and detect Solution) performed in ProxiPlate-384 Plus plates (Perkin Elmer, Waltham, Mass.). Staurosporine, a non-selective kinase inhibitor was used as a positive control. Compounds diluted in DMSO were spotted into 384 well plates using a Labcyte Echo 550 Liquid Handling System prior to addition of IRAK4 enzyme and peptide substrate. Reaction solutions were delivered using a Multi-Flo (Bio-Tek Instruments). The enzyme and peptide solution was incubated with compound for 15 minutes at room temp before the reaction was initiated by the addition of ATP. The standard 5 μl reaction mixture contained 500 □M ATP, 2 □M peptide (STK1 Peptide), 0.75 nM of IRAK4 in reaction buffer (50 mM HEPES, pH 7.0, 0.02% NaN3, 0.01% BSA, 0.1 mM Orthovanadate, 5 mM MgCl2, 0.025% NP-40, 1 mM DTT). After 120 min of incubation at room temperature, 5 □l of Stop and Detect Solution (1:100 Cryptate labeled anti-phosphorylated peptide antibody solution and 125 nM Tracer in a 50 mM HEPES pH 7.0 detection buffer containing sufficient EDTA) was added. The plate was then further incubated for 60 minutes at room temperature and read on Envision 2103 Multilabeled reader (PerkinElmer) with excitation/emission/FRET emission at 340 nm/615 nm/665 nm, respectively. Fluorescence intensities at 615 nm and 665 nm emission wavelengths were expressed as a ratio (665 nm/615 nm). |
| Affinity data for this assay | |
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