RRM2 and rheumatoid arthritis: An additional gene target for RA therapy has been proposed by Wang et al. They developed a peptide–polycation lipid-protamine-DNA (LPD) conjugated cell-permeable complex loaded with ribonucleotide reductase M2 (RRM2) siRNA (CCP-LPDR), aiming to increase apoptosis levels and inhibit proliferation of RA FLS.