Ginseng total saponin modulates the changes of α-actinin-4 of podocyte induced by diabetic conditions – Accepted Manuscript

Abstract: The actin cytoskeleton in the podocyte are essential for the maintenance of its normal structure and function, that disruption thereof is a feature of podocyte foot process effacement and is associated with proteinuria. α-Actinin-4 in podocytes serves as a linker protein binding actin filaments of cytoskeleton. To investigate the effect of ginseng total saponin (GTS) on the pathologic changes of podocyte α-actinin-4 induced by diabetic conditions, we cultured mouse podocytes under normal glucose (5 mM) or high glucose (HG, 30 mM), and advanced glycosylation end products (AGE) or not added conditions, and treated with GTS. In confocal imaging, α-actinin-4 colocalized with the ends of F-actin fibers in cytoplasm, however, diabetic conditions disrupted F-actin fibers and concentrated α-actinin-4 molecules at peripheral cytoplasm. GTS upregulated α-actinin protein in time- and dose-dependent manners, and suppressed receptor for AGE levels in Western blotting. Diabetic conditions, including HG, AGE, and both, decreased cellular α-actinin-4 protein levels at 24 and 48 h. Such quantitative and qualitative changes of α-actinin-4 protein induced by diabetic conditions were mitigated by GTS. These findings imply that both HG and AGE have an influence on the distribution and amount of α-actinin-4 of podocytes, which can be recovered by GTS.