In vitro activity: WY 14643 (10 μM) almost completely inhibits interleukin-1-induced production of interleukin-6 and prostaglandin and expression of cyclooxygenase-2 in aortic smooth-muscle cells, through repression of NF-κB signaling. WY14643 (250 μM) reduces VCAM-1 expression levels significantly, to 52 % of TNF-α-stimulated human endothelial cells. Pretreatment of endothelial cells with WY 14643 (10 μM) before TNF-α stimulation reduces U937 cell adhesion by 50%.

Kinase Assay: Pirinixic acid (Wy-14643) is a potent agonist of PPARα, with EC50s of 0.63 μM, 32 μM for murine PPARα and PPARγ, and 5.0 μM, 60 μM, 35 μM for human PPARα, PPARγ and PPARδ, respectively. 

Cell Assay: Synovial fibroblasts are treated with LPS (100 μg/mL) in the presence or absence of Pirinixic acid. PPAR-α siRNA-transfected cells are also treated with LPS (100 μg/mL) together with Pirinixic acid. After stimulation, the production of NO is determined using Griess reagents. Briefly, 300 μL of supernatant is mixed with 100 μL of Griess reagent and 2.6 mL of deionized water. The mixture is incubated for 30 min at room temperature, and the absorbance at 548 nm is measured. The concentrations of NO in the supernatants are calculated from a standard curve