Next, to further confirm the findings with Gö6976 that PKD1 is required for the TLR/IL-1R-mediated expression of cytokines and chemokines in HFLS-RA, we silenced PKD1 expression by transiently transfecting HFLS-N and HFLS-RA with non-target siRNA (NT siRNA; control cells) or PKD1-specific siRNA (PKD1-siRNA; PKD1-knockdown cells). Here, IL1R1 is linked to rheumatoid arthritis.