Podocyte Injury: The Role of Proteinuria, Urinary Plasminogen and Oxidative Stress.

Podocyte Injury: The Role of Proteinuria, Urinary Plasminogen and Oxidative Stress. Am J Physiol Renal Physiol. 2016 Jun 22;:ajprenal.00162.2016 Authors: Raij L, Tian R, Wong JS, He JC, Campbell KN Abstract Podocytes are the key target for injury in proteinuric glomerular diseases that result in podocyte loss, progressive focal segmental glomerular sclerosis (FSGS) and renal failure. Current evidence suggests that the initiation of podocyte injury and associated proteinuria can be separated from factors that drive and maintain these pathogenic processes leading to FSGS. In nephrotic urine aberrant glomerular filtration of Plasminogen (Plg) is activated to the biologically active serine protease Plasmin by urokinase type plasminogen activator (uPA). In-vivo inhibition of uPA mitigates Plg activation and development of FSGS in several proteinuric models of renal disease including 5/6 nephrectomy. Here we show that Plasminogen (Plg) is markedly increased in the urine in two murine models of proteinuric kidney disease associated with podocyte injury: Tg26 HIV-associated nephropathy and the Cd2ap-/- model of FSGS. We show that human podocytes express uPA and three Plg receptors: uPAR, tPA and Plg-RKT. We demonstrate that Plg treatment of podocytes specifically upregulates NADPH oxidase isoforms NOX2/NOX4 and increases production of mitochondrial-dependent superoxide anion (O2- ) that promotes endothelin-1 synthesis. Plg via O2- also promo...
Source: American Journal of Physiology. Renal Physiology - Category: Physiology Authors: Tags: Am J Physiol Renal Physiol Source Type: research