N-acylethanolamines anandamide (AEA)—a dual fatty acid amide hydrolase/cyclooxygenase-2 (FAAH/COX-2) inhibitor—inhibited MAPK signaling in patients with RA and desensitizes TRPA1 and downregulates IL in COX-2-dependent MMP-3 levels (Lowin et al., 2015). Here, PTGS2 is linked to rheumatoid arthritis.