FOXK1 and rheumatoid arthritis: Based on all these results, we concluded that, under pathological condition, HDAC3 interacted with FOXK1, deacetylated FOXK1 and increased FOXK1 protein stability by inhibiting its lysosomal degradation, leading to enhanced interferon signaling and activation of RA-FLSs, while propionate disrupted HDAC3-FOXK1 interaction to reduce protein stability of FOXK1, resulting in blocked interferon signaling and deactivation of RA-FLSs (Fig. 5v).