Kinase experiment:

Assays are conducted using both hLPA1/CHO and mLPA1/CHO cells. A cell pellet of hLPA1/CHO or mLPA1/CHO cells is resuspended in appr 20 mL of ice-cold membrane buffer containing 10 mM HEPES, pH 7.4, 1 mM dithiothreitol, and protease inhibitors. Cells are sonicated, and the cell lysate is centrifuged at 2000 rpm for 10 min at 4℃. The supernatant is further centrifuged at 25,000 rpm for 70 min at 4℃. The membrane pellet is resuspended in 5 mL of ice-cold membrane buffer and homogenized using a Potter-Elvehjem tissue grinder. Final protein concentration is determined using the Bradford Protein Assay Kit. Known amounts of AM095 (diluted in dimethyl sulfoxide) or vehicle (dimethyl sulfoxide) are added to 25 to 40 μg of hLPA1/CHO or mLPA1/CHO membranes and 0.1 nM [35S]-GTPγS in buffer (50 mM HEPES, 0.1 mM NaCl, 10 mM MgCl2, 50 μg/mL saponin, pH 7.5) containing 0.2% fatty acid-free human serum albumin and 5 μM GDP. To test for LPA1 antagonist activity, the ability of AM095 to inhibit GTPγS binding stimulated by 900 nM LPA (18:1) is measured. Alternatively, to test for agonist effects, the ability of AM095 to stimulate GTPγS binding in the absence of LPA is measured. Reactions are incubated for 30 min at 30℃, before harvesting membranes onto glass filter binding plates and washing three times with cold buffer containing 50 mM HEPES, pH 7.4, 100 mM NaCl, 10 mM MgCl2 using a Brandel 96-tip cell harvester. Plates are dried and then cpm are evaluated by using a Packard TopCount NXT microplate scintillation counter.

Animal experiment:

Mice underwent UUO or sham surgery to the left kidney. In brief, a longitudinal, upper left incision is performed to expose the left kidney. The renal artery is located and a 6/0 silk thread is passed between the artery and the ureter. The thread is looped around the ureter and knotted three times insuring full ligation of ureter. The kidney is returned to abdomen, the abdominal muscle is sutured, and the skin is closed with staples. The contralateral (right) kidney served as an uninjured control. AM095 (30 mg/kg) or vehicle (water) is given 1 to 4 h before UUO and then b.i.d. thereafter by oral gavage. After 8 days, mice are euthanized using inhaled CO2, and the kidneys are harvested and cut in half for histopathological and biochemical analysis of fibrosis. To assess fibrosis, half of the kidney is fixed in 10% neutral buffered formalin and stained using Masson's trichrome. The other half of the kidney is frozen at –80℃ for subsequent biochemical analysis of collagen content.

AM095 is a novel, potent and orally bioavailable antagonist of lysophosphatidic acid type 1 receptor (LPA1) with IC50 values of 0.73 and 0.98 μM for mouse or recombinant human LPA1, respectively [1].

In vitro, AM095 has shown to inhibit LPA1-induced chemotaxis of both mouse LPA1/CHO cells and human A2058 melanoma cells with IC50 values of 0.78 μM and 0.23μM [1].

In vivo, AM095 could dose-dependently block LPA-induced histamine release with an ED50 value of 8.3 mg/kg in mice. Additionally, AM095 has been revealed to remarkably reduce the BALF collagen and protein with an ED50 value of 10 mg/kg in lungs. AM095 has also shown to decrease both macrophage and lymphocyte infiltration induced by bleomycin in mice [1].

References:
[1] Swaney JS1, Chapman C, Correa LD, Stebbins KJ, Broadhead AR, Bain G, Santini AM, Darlington J, King CD, Baccei CS, Lee C, Parr TA, Roppe JR, Seiders TJ, Ziff J, Prasit P, Hutchinson JH, Evans JF, Lorrain DS. Pharmacokinetic and pharmacodynamic characterization of an oral lysophosphatidic acid type 1 receptor-selective antagonist. J Pharmacol Exp Ther. 2011 Mar;336(3):693-700.