PDPN and rheumatoid arthritis: In vitro treatment with pro-inflammatory cytokines known to promote EMT-like behavior (i.e., IL-1β, TNF-α, and TGF-β1) induced expression of both α-SMA and podoplanin in OA-FLS, thus evoking the role of podoplanin in the activation of RA-FLS leading to their increased migratory potential [172].