PLAU and rheumatoid arthritis: During the pathogenesis of RA, urokinase-type plasminogen activator (uPA) secreted by neutrophils, chondrocytes and monocytes interacts with uPAR, a receptor expressed on macrophages, FLS, chondrocytes and VECs, thereby secreting a variety of cytokines, chemokines, growth factors and MMPs to promote the progression of RA (Dinesh and Rasool, 2018).