INHIBITION OF JNK AND P38 MAPK PHOSPHORYLATION BY5-(ACETYLAMINO)-4-OXO-6-PHENYL-2-HEXENOIC ACID METHYL ESTER AND 4-PHENYL-BUTENOIC ACIDDECREASES SUBSTANCE P-INDUCED TNF-α UPREGULATION IN MACROPHAGES

摘要

The interactions between the immune and nervous systems play an important role in immune and inflammatory conditions. Substance P (SP), the unidecapeptide RPKPQQFFGLM-NH2, is known to upregulate the production of pro-inflammatory cytokines such as tumor necrosis factor (TNF)-α. We report here that 5-(acetylamino)-4-oxo-6-phenyl-2-hexenoic acid methyl ester (AOPHA-Me) and 4-phenyl-3-butenoic acid (PBA), two anti-inflammatory compounds developed in our laboratory, reduce SP-stimulated TNF-α expression in RAW 264.7 macrophages. We also show that AOPHA-Me and PBA both inhibit SP-stimulated phosphorylation of JNK and p38 MAPK. Furthermore, molecular modeling studies indicate that both AOPHA-Me and PBA dock at the ATP binding site of apoptosis signal-regulating kinase 1 (ASK1), a member of the MAPKs upstream of both JNK and p38 MAPK, with predicted interaction energies of −7.0 kcal/mol and −5.9 kcal/mol, respectively; this binding overlaps with that of staurosporine, a known inhibitor of ASK1. Taken together, these findings suggest that AOPHA-Me and PBA inhibition of TNF-α expression in SP-stimulated RAW 264.7 macrophages is a consequence of the inhibition JNK and p38 MAPK phosphorylation. We have previously shown that AOPHA-Me and PBA inhibit the amidative bioactivation of SP, which also would be expected to decrease formation of pro-inflammatory cytokines. It isconceivable that this dual action of inhibiting amidation and MAPK phosphorylation may beof some advantage in enhancing the anti-inflammatory activity of a therapeuticmolecule.