Ginseng total saponin modulates the changes of α-actinin-4 in podocytes induced by diabetic conditions.
BACKGROUND
The actin cytoskeleton in podocytes is essential for the maintenance of its normal structure and function. Its disruption is a feature of podocyte foot-process effacement and is associated with proteinuria. α-Actinin-4 in podocytes serves as a linker protein binding the actin filaments of the cytoskeleton.


METHODS
To investigate the effect of ginseng total saponin (GTS) on the pathological changes of podocyte α-actinin-4 induced by diabetic conditions, we cultured mouse podocytes under normal glucose (5mM) or high glucose (HG, 30mM) conditions, with or without the addition of advanced glycosylation end products (AGE), and treated with GTS.


RESULTS
In confocal imaging, α-actinin-4 colocalized with the ends of F-actin fibers in cytoplasm, but diabetic conditions disrupted F-actin fibers and concentrated α-actinin-4 molecules at the peripheral cytoplasm. GTS upregulated α-actinin protein in a time- and dose-dependent manner, and suppressed the receptor for AGE levels in western blotting. Diabetic conditions, including HG, AGE, and both together, decreased cellular α-actinin-4 protein levels at 24 h and 48 h. Such quantitative and qualitative changes of α-actinin-4 protein induced by diabetic conditions were mitigated by GTS.


CONCLUSIONS
These findings imply that both HG and AGE have an influence on the distribution and amount of α-actinin-4 in podocytes that can be recovered by GTS.
Department of Pediatrics, College of Medicine, Chungbuk National University, Cheongju, Korea.
Tae-Sun
TS
Ha
Department of Pediatrics, College of Medicine, Chungbuk National University, Cheongju, Korea.
Ji-Young
JY
Choi
Department of Pediatrics, College of Medicine, Chungbuk National University, Cheongju, Korea.
Hye-Young
HY
Park
Department of Pediatrics, College of Medicine, Chungbuk National University, Cheongju, Korea.
Ja-Ae
JA
Nam
Department of Pediatrics, College of Medicine, Chungbuk National University, Cheongju, Korea.
Su-Bin
SB
Seong
Panax ginseng; diabetic nephropathy; ginseng total saponin; podocyte; α-actinin-4