Proteolysis and inflammation of the kidney glomerulus

Abstract

Proteases play a central role in regulating renal pathophysiology and are increasingly evaluated as actionable drug targets. Here, we review the role of proteolytic systems in inflammatory kidney disease. Inflammatory kidney diseases are associated with broad dysregulations of extracellular and intracellular proteolysis. As an example of a proteolytic system, the complement system plays a significant role in glomerular inflammatory kidney disease and is currently under clinical investigation. Based on two glomerular kidney diseases, lupus nephritis, and membranous nephropathy, we portrait two proteolytic pathomechanisms and the role of the complement system. We discuss how profiling proteolytic activity in patient samples could be used to stratify patients for more targeted interventions in inflammatory kidney diseases. We also describe novel comprehensive, quantitative tools to investigate the entirety of proteolytic processes in a tissue sample. Emphasis is placed on mass spectrometric approaches that enable the comprehensive analysis of the complement system, as well as protease activities and regulation in general.

Kidney organoid systems for studies of immune-mediated kidney diseases: challenges and opportunities

“…Antibody deposition at the glomerular basement membrane can result in membranous nephropathy that is characterized by high proteinuria and a granular pattern of glomerular immune deposits. Autoantibodies against antigens expressed by healthy podocytes including the PLA2R (M-type phospholipase A2 receptor) (Beck et al 2009 ) or Thrombospondin type-1 domain containing 7 (Tomas et al 2014 ) are detected in the majority of patients with membranous nephropathy (Tomas et al 2021 ). However, in some cases, the autoantigen is still elusive.…”