MMP1 and rheumatoid arthritis: In conclusion, our data show that PIP-18 significantly inhibits sPLA2-IIA enzymatic activity and downregulates sPLA2-IIA and MMPs (MMP-1, MMP-2, MMP-3, MMP-9) at both the transcript and the protein level in IL1-β-induced RA SF cells via attenuation of p38 MAPK phosphorylation.