MMP13 and rheumatoid arthritis: Consistently, BMS309403 clearly decreased FABP4 expression in synovial M1-polarized macrophages (Fig. 6d–f) and serum (Fig. S2C) of C57BL/6 J mice after AIA modeling, which suppressed synovitis (Fig. S9F), the proliferation and invasion of FLSs (Fig. 7e, m and Fig. S9G), the angiogenesis of H-type vessels (Fig. 7f, n), knee joint cartilage thinness (Fig. S9H), Col2a1 degradation (Fig. 7g, o and Fig. S9I), and MMP13 expression (Fig. 7h, p) to alleviate experimental RA progression.