Many previous studies have shown that induction of uPA, uPA receptor (uPAR), and PAI-1 may occur in lung endothelial cells (ECs) through a uPA-mediated feedback pathway. Soluble urokinase-type plasminogen activator receptor (suPAR) is a soluble form of the urokinase plasminogen activator receptor (uPAR) that is produced upon cleavage of membrane-bound uPAR. It is found in various body fluids, including blood, urine and cerebrospinal fluid. It is now known that Pulmonary function in physiological and patho-physiological condition is regulated by these molecules. On the other hand, Protease nexin-1 or serine protease inhibitor (Serpin E2) is intricately linked in the physiological homeostasis and interacts with uPA system. These are the key elements of the pulmonary renal cascade regulating multiple physiological functions. Key words: Urokinase, suPAR, lungs, SERPIN, physiological, airways