Ginseng total saponin regulates podocyte P-cadherin/β-catenin unit in diabetic condition

Abstract

Proteinuric conditions demonstrate structural and compositional changes of the foot processes and slit diaphragms between podocytes. β-Catenin in podocytes serves as an adapter protein anchoring P-cadherin of slit diaphragms to actin filaments of podocyte cytoskeleton. To investigate the effect of ginseng total saponin (GTS) on the pathologic changes of podocyte P-cadherin/β-catenin unit induced by diabetic conditions, we cultured mouse podocytes under: 1) normal glucose (5 mM, = control); 2) high glucose (HG, 30 mM); 3) advanced glycosylation end products (AGE)-added; or 4) HG plus AGE-added conditions and treated with GTS. In confocal imaging, β-catenin colocalized with P-cadherin at intercellular junction area, predominantly. However, diabetic conditions relocalized and concentrated both molecules at perinuclear cytoplasmic area. In Western blotting, diabetic conditions, especially HG plus AGE-added condition, also decreased cellular β-catenin protein levels at 6, 24, and 48 hours. GTS improved such quantitative and qualitative changes of β-catenin. These findings imply that HG plus AGE have an influence on the redistribution and amount of P-cadherin/β-catenin unit of podocytes, which can be reversed by GTS.