RPS6KB1 and rheumatoid arthritis: To test this hypothesis, we assessed the expression of p70s6K, p-p70s6K, 4E-BP1, and p-4E-BP1 in RA-FLS co-cultured with BMDM-sEVs from different sources (Fig. 7F) and in RA-FLS transfected with miR-100-5p mimics or inhibitors (Fig. 8D and E).