A Review of Podocyte Biology

Abstract

Background: Podocyte biology is a developing science that promises to help improve understanding of the mechanistic nature of multiple diseases associated with proteinuria. Proteinuria in nephrotic syndrome has been linked to mechanistic dysfunctions in the renal glomerulus involving the function of podocyte epithelial cells, including podocyte foot process effacement. Summary: Developments in imaging technology are improving knowledge of the detailed structure of the human renal glomerulus and cortex. Podocyte foot processes attach themselves to the glomerular capillaries at the glomerular basement membrane (GBM) forming intercellular junctions that form slit diaphragm filtration barriers that help maintain normal renal function. Damage in this area has been implicated in glomerular disease. Injured podocytes undergo effacement whereby they lose their structure and spread out, leading to a reduction in filtration barrier function. Effacement is typically associated with the presence of proteinuria in focal segmental glomerulosclerosis, minimal change disease, and diabetes. It is thought to be due to a breakdown in the actin cytoskeleton of the foot processes, complex contractile apparatuses that allow podocytes to dynamically reorganize according to changes in filtration requirements. The process of podocyte depletion correlates with the development of glomerular sclerosis and chronic kidney disease. Focal adhesion complexes that interact with the underlying GBM bind the podocytes within the glomerular structure and prevent their detachment. Key Messages: Knowledge of glomerular podocyte biology is helping to advance our understanding of the science and mechanics of the glomerular filtering process, opening the way to a variety of new potential applications for clinical targeting.

Transcription factor 21 expression in injured podocytes of glomerular diseases

“…Tcf21 acting as an anti-apoptotic player can help stop podocytes from resulting in cell death. Second, actin cytoskeleton reorganization is well documented in podocyte injury 25,26 . Podocytes are firmly attached to the glomerular basement membrane and resist strong filtration pressure from the basement membrane.…”

AGE-Induced Suppression of EZH2 Mediates Injury of Podocytes by Reducing H3K27me3

“…A hallmark of DKD is proteinuria. The pathogenesis of proteinuria is mediated by the injury of podocytes, an important part of the glomerular filtration barrier [4].…”

Role of Transient Receptor Potential Canonical Channel 6 (TRPC6) in Diabetic Kidney Disease by Regulating Podocyte Actin Cytoskeleton Rearrangement

“…These proteins altogether regulate the polymerization, maintenance, and depolymerization of the actin cytoskeleton by different signaling pathways. The actin cytoskeleton proteins have two major functions depending their localization in the cell: one is the longitudinal actin microfilaments that provide structural support for cells with certain contractile and diastolic functions and also serve as a bridge linking intracellular molecular signaling pathways; the other one is a meshwork of actin filaments existing under the cell membrane that mediate transmembrane proteins and transmembrane signaling pathways [51]. The podocyte injury induced by many pathological factors causes the rearrangement of actin cytoskeleton, which disorganized the original structure of actin fibers, characterized as less-branched and shortened stalks.…”