CHEMBL3889172

Receptor Assay: Engagement of the LPA1 receptor by its ligand, oleoyl-L-α-lysophosphatidic acid (LPA), leads to the release of intracellular stores of calcium into the cytoplasm mediated through a Gq-driven increase in inositol triphosphate (IP3) levels. Gq is a heterotrimeric G protein subunit that activates phospholipase C. The ability of test compounds to prevent LPA-driven intracellular release of stored calcium from RH7777 cells expressing human LPA1 receptors was assayed by stimulating the cells with LPA in the presence of various test compounds to measure the test compounds' antagonism, i.e. activity in vitro.  Approximately 10,000 cells in normal culture medium (Dulbecco's Modified Eagle Media, 10% Foetal Calf Serum) were dispensed per assay well in a black clear bottom collagen coated 384 well plate (Beckton Dickinson). Cells were allowed to settle for thirty minutes at room temperature before being incubated overnight at 37° C., 5% CO2. Sixteen to twenty hours after dispensing, the cells were loaded with a calcium-sensitive fluorescent dye by replacing the culture medium with assay buffer (1x Hanks buffered saline, 25 mM HEPES, 0.1% w/v fatty acid free BSA (bovine serum albumin), pH7.4) containing 1.25 mM probenecid and 1x Calcium 5 Reagent (Molecular Devices). Cells were incubated at 37° C. for one hour to allow for dye uptake.