Hence, the mRNA expression of these prominent proteins (MMP3 and MMP9) was also analyzed upon estrogen exposure in RA synovial fibroblasts, and it was found that E2 successfully downregulates the expression of MMP3 and MMP9; this aids in the remission of cartilage degradation, which peaks in RA (Figure 5B,C). The gene discussed is MMP9; the disease is rheumatoid arthritis.