Ginsenoside Rb1 reverses H2O2-induced senescence in human umbilical endothelial cells: involvement of eNOS pathway.
OBJECTIVE
Senescence of endothelial cells has been implicated in endothelial dysfunction and atherogenesis. This study investigated the effects of Rb1, a major ginsenoside in ginseng, on H2O2-induced senescence in primary human umbilical vein endothelial cells (HUVECs).


RESULTS
Real-time PCR and Western blot were used to detect the mRNA and protein expression, respectively. H2O2 (40∼100 μmol/L) effectively increased SA-β-gal activity and PAI-1 mRNA levels, two important senescence related biomarkers, in HUVECs, which were dramatically inhibited by Rb1 pre-incubation. Furthermore, Rb1 administration reversed the H2O2-decreased protein and mRNA levels of eNOS and its phosphorylation at Ser-1177, and the increased eNOS phosphorylation at Thr-495. As a result, Rb1 pretreatment restored the NO generation, as assayed by nitrate reductase method. However, pretreatment with L-NAME, a NOS inhibitor, abolished all the inhibitory effects of Rb1 on senescence. Importantly, Rb1 modulated the H2O2-altered caveolin-1 and pAkt, two most important regulators of eNOS expression and activity, in HUVECs.


CONCLUSIONS
We showed that Rb1 effectively protects HUVECs from senescence through eNOS modulation.
Department of Cardiology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China.
Ding-Hui
DH
Liu
Yan-Ming
YM
Chen
Yong
Y
Liu
Bao-Shun
BS
Hao
Bin
B
Zhou
Lin
L
Wu
Min
M
Wang
Lin
L
Chen
Wei-Kang
WK
Wu
Xiao-Xian
XX
Qian
D015153:Blotting, Western; D016922:Cellular Senescence / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects; D036145:Ginsenosides / Q000494:pharmacology*; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000008:administration & dosage / Q000633:toxicity; D009569:Nitric Oxide / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D001616:beta-Galactosidase / Q000378:metabolism
D036145:Ginsenosides; D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; D009569:Nitric Oxide; C442759:ginsenoside Rb1; D006861:Hydrogen Peroxide; D052250:Nitric Oxide Synthase Type III; C061901:GLB1 protein, human; D001616:beta-Galactosidase