Inhibition of human MoGAT-2 expressed in human Caco2 cells assessed as inhibition of 2-O-Hexadecylglycerol hydrolysis pretreated for 30 mins by LC-MS analysis
Inhibition of human recombinant MGAT2 assessed as reduction in enzyme-mediated deacylation of oleoyl-CoA incubated for 20 mins by CPM dye based fluorescence assay
Inhibition Assay: A test for MGAT2 inhibitory action of test compounds was conducted in accordance with a partially modified version of the method described in John F. Lockwood et al., Am. J. Physiol. Endocrinol. Metab., 2003, 285, E927.Bac-to-Bac Baculovirus Expression System (Life Technologies Japan) was used to express human MGAT2 in insect cells (Sf9) (Life Technologies Japan). These cells were sonicated and centrifuged at 100,000 g.times.1 hr to give a precipitate. The precipitate was used as a human MGAT2 enzyme fraction in this assay.This test was conducted using a black flat-bottom 96-well plate (Corning). A buffer solution with final concentrations of 5 mM magnesium chloride, 100 mM sucrose and 100 mM Tris-HCl (pH=7.5) was prepared and test compounds prepared in various concentrations using dimethyl sulfoxide were added thereto to give a final dimethyl sulfoxide concentration of 1%. The MGAT2 enzyme fraction was added thereto to give a final concentration of 0.5 .mu.g/ml.
Inhibition Assay: An MGAT2 inhibition test for test compounds was conducted in accordance with a partially modified version of the method described in John F. Lockwood et al., Am. J. Physiol. Endocrinol. Metab., 2003, 285, E927.A 10 mg/mL microsomal fraction of human small intestine (duodenum- and jejunum-derived fraction purchased from Becton Dickinson Japan) was used as an enzyme source.The test was conducted using a flat-bottom 96-well plate (Corning).A buffer solution with final concentrations of 5 mM magnesium chloride, 1.25 mg/ml bovine serum albumin and 100 mM Tris-HCl (pH=7.5) was prepared and the microsomal fraction of human small intestine was added thereto to give a final concentration of 5 .mu.g/ml. Test compounds prepared in various concentrations using dimethyl sulfoxide were added thereto to give a final dimethyl sulfoxide concentration of 1% and a reaction was performed at room temperature for 5 min.
Inhibition Assay: The in vitro inhibitory activity of compounds against human MOGAT-2 is evaluated in this assay. MOGAT-2 transfers an oleoyl group to monooleoyl-glycerol (MAG) from oleoyl-CoA to form dioleoyl-glycerol (DAG) in the intestinal triglyceride resynthesis pathway. The assay takes advantage of Microscint E extraction, which extracts hydrophobic molecules selectively over hydrophilic ones to separate the 14C-oleoyl-CoA from 14C-DAG.Genetically engineered insect SF9 cells express human MOGAT-2. Prepare the cell lysate in 20 mM of NaCl with protease inhibitor (Roche Cat#11873580001). Homogenize the SF9 cells expressing human MOGAT-2 at 15,000 rpm for 20x2 seconds (PT-3100 Polytrone). Centrifuge the homogenate at 1000 g for 10 minutes at 4 C. Collect the supernatant into a separate tube for protein quantification and activity testing. Purify the glycerol monooleate substrate (Spectrum Chemical, CAS#25496-72-4) chromatographically.