Figure 4. FAAH inhibition enhances AEA-induced J-series PG synthesis and apoptosis.

(A). FAAH inhibition increases AEA-induced cell death. JWF2 keratinocytes were pretreated with 0.05, 0.5 or 5 µM URB597 or DMSO (URB597 vehicle) for 30 minutes and the cells exposed to 15 µM AEA or ethanol. Cell viability was measured by MTS assay as described previously. Asterisk indicates that the viability of URB597 + AEA-treated cells is statistically significantly different from the viability of cells treated with AEA alone (* = P ≤ 0.05). (B). FAAH inhibition increases AEA-induced apoptosis. Cells were pretreated with 5 µM URB and then exposed to 10 µM AEA or ethanol (AEA vehicle). Protein levels of FL-PARP, CL-PARP, CL-caspase-3 and GAPDH were measured by Western analysis. (C). Co-administration of AEA with the FAAH inhibitor URB597 induces DNA fragmentation. Cells were treated with vehicle (Ethanol + DMSO), URB597, sublethal AEA, or URB597 + sublethal AEA and TUNEL positive cells or TUNEL with corresponding DAPI stain visualized by fluorescence microscopy at 10X (C) or 40X (D) magnification. (E). URB597 enhances AEA-induced J-series PG synthesis. J-series PG levels were measured by ELISA in the culture medium of cells pretreated with 5 µM URB597 or DSMO followed by cell exposure to 10 µM AEA or ethanol. (F). JWF2 cells were treated with 20 µM AEA or an equivalent volume of ethanol for 1, 2, 4, or 6 hours and FAAH protein expression measured The multiple TRPV1 bands likely represent slice variants as reported previously [41].