HAPLN1 and rheumatoid arthritis: Results of the wound healing assay showed a decrease in the level of migration exhibited by HAPLN1OE-transfected RA-FLSs (Figure 3C), whereas rHAPLN1 confirmed the effects of HAPLN1 on RA-FLSs which showed a significant increase in the proliferation activity (Figure 4A and Supplementary Figure S5) and a reduction in apoptosis, especially during the early phase (Figures 4B, C).