Ginsenoside Rb1 protects against 6-hydroxydopamine-induced oxidative stress by increasing heme oxygenase-1 expression through an estrogen receptor-related PI3K/Akt/Nrf2-dependent pathway in human dopaminergic cells.
Phytoestrogens are polyphenolic non-steroidal plant compounds with estrogen-like biological activity. Ginseng, the root of Panax ginseng C.A. Meyer (Araliaceae), is a popular traditional herbal medicine. Ginsenoside Rb1 (Rb1), an active component commonly found in ginseng root, is a phytoestrogen that exerts estrogen-like activity. In this study, we demonstrate that the phytoestrogen Rb1 inhibits 6-hydroxydopamine (6-OHDA)-induced oxidative injury via an ER-dependent Gbeta1/PI3K/Akt and heme oxygenase-1 (HO-1) pathway. Pretreatment of SH-SY5Y cells with Rb1 significantly reduced 6-OHDA-induced caspase-3 activation and subsequent cell death. Rb1 also up-regulated HO-1 expression, which conferred cytoprotection against 6-OHDA-induced oxidative injury. Moreover, Rb1 induced both Nrf2 nuclear translocation, which is upstream of HO-1 expression and PI3K activation, a pathway that is involved in induced Nrf2 nuclear translocation, HO-1 expression and cytoprotection. Also, Rb1-mediated increases in PI3K activation and HO-1 induction were reversed by co-treatment with ICI 182,780 and pertussis toxin. Taken together, these results suggest that Rb1 augments the cellular antioxidant defenses through ER-dependent HO-1 induction via the Gbeta1/PI3K/Akt-Nrf2 signaling pathway, thereby protecting cells from oxidative stress. Thus our study indicates that Rb1 has a partial cytoprotective role in dopaminergic cell culture systems.
Hwang
Yong Pil
YP
College of Pharmacy, Chungnam National University, Daejeon, South Korea.
Jeong
Hye Gwang
HG
D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004298:Dopamine / Q000502:physiology*; D036145:Ginsenosides / Q000494:pharmacology*; D051547:Heme Oxygenase-1 / Q000096:biosynthesis*; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*; D051058:Oncogene Protein v-akt / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects*; D016627:Oxidopamine / Q000037:antagonists & inhibitors* / Q000633:toxicity; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D012313:RNA / Q000096:biosynthesis / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D011960:Receptors, Estrogen / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
D036145:Ginsenosides; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D017382:Reactive Oxygen Species; D011960:Receptors, Estrogen; D012313:RNA; C442759:ginsenoside Rb1; D016627:Oxidopamine; D051547:Heme Oxygenase-1; D019869:Phosphatidylinositol 3-Kinases; D051058:Oncogene Protein v-akt; D053148:Caspase 3; D053453:Caspase 9; D004298:Dopamine