Indoxyl sulfate induces endothelial cell senescence by increasing reactive oxygen species production and p53 activity.
OBJECTIVE
We have reported that indoxyl sulfate (IS), a uremic toxin, accelerates proximal tubular cell senescence. Asymmetric dimethylarginine (ADMA), an inhibitor of nitric oxide synthase, has been reported to induce endothelial cell senescence. This study aimed to determine whether IS induces endothelial cell senescence in comparison with ADMA, and to investigate its molecular mechanism.


METHODS
Human umbilical vein endothelial cells (HUVECs) were incubated with IS (250 μM) and/or ADMA (10 μM). These concentrations were comparable with their mean serum levels in hemodialysis patients. Cell senescence was evaluated by measuring senescence-associated beta-galactosidase (SA-β-gal) activity. N-acetylcysteine, an antioxidant, and pifithrin alpha p-nitro, a p53 inhibitor, were used to determine the role of reactive oxygen species (ROS) and p53 in the induction of cell senescence.


RESULTS
Both IS and ADMA significantly increased SA-β-gal activity in HUVECs. Further, some additional increase in SA-β-gal activity was observed when IS and ADMA were co-incubated. Preincubation of N-acetylcysteine or pifithrin alpha p-nitro significantly inhibited SA-β-gal activity induced by IS and ADMA in HUVECs. Thus, both IS and ADMA induced endothelial senescence through ROS and p53.


CONCLUSIONS
IS induces endothelial cell senescence by increasing ROS production and p53 activity, like ADMA.
Department of Advanced Medicine for Uremia, Nagoya University School of Medicine, Tsurumai-cho, Showa-ku, Nagoya, Japan.
Yelixiati
Y
Adelibieke
Hidehisa
H
Shimizu
Gulinuer
G
Muteliefu
Dilinaer
D
Bolati
Toshimitsu
T
Niwa
D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D016922:Cellular Senescence / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D007200:Indican / Q000494:pharmacology*; D007676:Kidney Failure, Chronic / Q000097:blood; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D017382:Reactive Oxygen Species / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000187:drug effects* / Q000502:physiology
D004791:Enzyme Inhibitors; D017382:Reactive Oxygen Species; D016159:Tumor Suppressor Protein p53; C487735:dimethylarginine; D001120:Arginine; D019001:Nitric Oxide Synthase; D007200:Indican