External ID: CHEMBL5104715

Protocol: N/A

Comment: Journal: Eur J Med Chem
Year: 2022
Volume: 231
First Page: 114139
Last Page: 114139
DOI: 10.1016/j.ejmech.2022.114139

External ID: CHEMBL5104716

Protocol: N/A

Comment: Journal: Eur J Med Chem
Year: 2022
Volume: 231
First Page: 114139
Last Page: 114139
DOI: 10.1016/j.ejmech.2022.114139

External ID: CHEMBL5104717

Protocol: N/A

Comment: Journal: Eur J Med Chem
Year: 2022
Volume: 231
First Page: 114139
Last Page: 114139
DOI: 10.1016/j.ejmech.2022.114139

External ID: ST2_IL33_Inhibitors_Primary_Screening_77700

Protocol: High-throughput screening was performed at Indiana University screening facility (Indiana University, Indianapolis, IN).

In summary, a mixture of ST2 and IL-33 was prepared by adding 0.30 microL of 14.1 microM recombinant human ST2-Fc Chimera and 0.30 microL of 55.25 biotinylated recombinant human IL-33 to 1.4 mL of assay buffer. In the HTS, each well of a 384-well Proxi-plate was first blocked by 100 microL of assay buffer for 1 h at room temperature. After removing the blocking buffer, 20 microL of ST2/IL-33 mixture was pipetted into each well and incubated at room temperature for 1 h followed by addition of compounds at 17 microM (0.8 microL) to each well and incubated at room temperature for 1 h. Ten microliters of 60 microg/mL anti-6xHis-conjugated AlphaLISA acceptor beads were added to each well and incubated at room temperature for 1 h before addition of 10 microL of 60 microg/mL of streptavidin-labeled AlphaLISA donor beads for incubation at room temperature for 30 min. Incubation of acceptor and receptor beads was conducted in darkness. The well with 3 nM ST2 alone was used as a negative control, whereas the ST2/IL-33 mixture with a human ST2 antibody added at 0.45 ng/microL was used as the positive control. Plates were read using the Envision Plate Reader. The buffer used in the assay contains 14.37 mL PBS, 30 microL Tween 20, and 600 microL of 5% bovine serum albumin in PBS.

Comment: PubChem active indicates >= 30% inhibition of ST2/IL-33 at 17 uM of the compound. Inconclusive: >=10% and < 30% inhibition.

External ID: VANDERBILT_HTS_GIRK2_MPD

Protocol: To screen for modulators of the G protein-gated inwardly-rectifying potassium channel subunit 2 (GIRK2) homomeric channels, HEK293 cells were engineered to overexpress GIRK2. These cells were screened using a high-throughput thallium-flux assay in a 384-well format. High-throughput thallium flux assays are based on three principles: (1) extracellular thallium can permeate through potassium channels into cells, (2) the fluorescent dye Thallos enters and stays in the cytoplasm of HEK293 cells, and (3) the fluorescence of Thallos increases dramatically when it interacts with thallium ions. Compounds that modulate the activity of an overexpressed channel, in this case GIRK2, are identified by the change in fluorescence that results from changes in thallium influx into cells through the overexpressed channel.

The screening protocol was conducted as follows. One hour prior to screening, cells were loaded with 1.5 micromolar (muM) Thallos in assay buffer (1x Hank's Balanced Salt Solution and 20 millimolar (mM) HEPES). The liquid handling and imaging was conducted using a kinetic-imaging plate reader, Panoptic (WaveFront Biosciences). Before screening, Thallos-containing buffer was removed from cells and replaced with 20 microliters (muL) per well of assay buffer. Compounds were dissolved in assay buffer at 20 muM. After 8 seconds of imaging, 20 muL of compound solution was added per well and allowed to incubate for 150 seconds. Next, 10 muL of a solution containing 2.0 mM thallium in Base Buffer (125 mM NaHCO3, 1 mM MgSO4, 1.8 mM CaSO4, 5mM Glucose, and 20 mM HEPES) was added to the wells. 30 seconds later, 12 muL of base buffer containing 2.0 mM thallium and 50 mM 2-methyl-2,4-pentanediol (MPD), a partially-activating concentration, was added to each well. MPD has is a previously-described GIRK2 channel activator. Data was collected for 60 seconds after this final addition. The positive control for this screen was 30 muM ivermectin, a natural product previously identified as a GIRK2 activator as part of a small-scale pilot screen. Microsoft Excel was utilized for data analysis. Data were normalized, F/Fo, on a well-to-well basis to account for differences in cell number. Compound activity was analyzed by comparing the sums of control-subtracted amplitudes of fluorescence intensity at 20 seconds after each thallium addition. The top 0.2% compounds corresponding to wells that demonstrated the largest increases in fluorescence were selected as "hits" for counter screening, as described below.

All 63,228 compounds screened using the method described above are listed in column OUTCOME_SCREEN_HITS. The 133 compounds selected as hits based on the above criteria are labelled with "100" in the ACTIVITY column. Fluorescent compounds were included in the inactive compounds and marked with "0" in the ACTIVITY column.

The 133 active compounds from column OUTCOME_SCREEN_HITS were tested for non-specific activity in untransfected HEK293 cells using assay conditions otherwise identical to the primary screen. Column OUTCOME_HEK_COUNTERSCREEN lists the 23 compounds that displayed an increase in fluorescence upon thallium addition with "100" in the ACTIVITY column.

The 110 compounds which were identified as hits in the primary screen but inactive when tested in untransfected HEK293 cells were tested for activity in GIRK2-overexpressing HEK293 cells that did not express NPY4 receptor. Column OUTCOME_GIRK2_COUNTERSCREEN lists the 44 compound that displayed an increase in fluorescence upon thallium addition with "100" in the ACTIVITY column.

The 44 active compounds from column OUTCOME_GIRK2_COUNTERSCREEN were tested at various concentrations to determine if compound activity was concentration dependent. Column OUTCOME_GIRK2_DOSE_RESPONSE provides the efficacy of these compounds; activity of all compounds at the provided concentrations was normalized to the activity of VU0537695 at 25 muM, which was the highest efficacy observed during this screening. For each compound concentration listed, the efficacy of that compound provided refers to the normalized, control-subtracted fluorescence intensity at 15 seconds after the addition of thallium. The 28 compounds that demonstrated >5% efficacy and concentration-dependent activity were labelled as "100" in the ACTIVITY column.

Finally, column PUBCHEM_ACTIVITY_OUTCOME combines all of the information from the above counterscreens together, indicating the 28 hits from this GIRK2 screen.

Comment: