title: Puerarin induces the upregulation of glutathione levels and nuclear translocation of Nrf2 through PI3K/Akt/GSK-3β signaling events in PC12 cells exposed to lead.
abstract: Oxidative stress is thought to be involved in lead-induced toxicity, especially affecting the brain. We reported previously that puerarin possesses antioxidative properties in the nervous system. Therefore, the aim of the present study was to test the hypothesis that puerarin inhibits lead acetate-induced oxidative stress in PC12 cells by interrupting phosphatidylinositol-3 kinase (PI3K)/Akt signaling through increasing glutathione (GSH) synthesis. Our results showed that puerarin attenuates oxidative stress in a concentration-dependent manner in PC12 cells exposed to lead acetate demonstrated by scavenging reactive oxygen species (ROS) and reducing lipid peroxidation (LPO). Treatment with puerarin significantly up-regulates glutamate cysteine ligase catalytic subunit (GCLc) expression both at its mRNA and protein levels, but not glutamate cysteine ligase modifier (GCLm) subunit, accompanying the elevation of cellular glutathione level. The increased nuclear accumulation of nuclear factor erythroid 2-related factor 2 (Nrf2) was not because of increased transcription of Nrf2 as Nrf2 transcript levels did not change after puerarin treatment. The effects of puerarin could be partially blocked by pharmacologic inhibition of PI3K and the glycogen synthase kinase 3β (GSK-3β) pathways with LY294002 and LiCl, respectively. On the other hand, puerarin treatment promoted Akt and GSK-3β phosphorylation in PC12 cells exposed to lead acetate. Moreover, puerarin failed to modulate the phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2), p-c-Jun N-terminal kinases (JNK), and p-p38 mitogen-activated protein kinase (MAPK) demonstrating some specificity for its action on the PI3K/GSK-3β pathway. These findings suggest that puerarin as a phytoestrogen might be an attractive agent for prevention and treatment of chronic diseases related to lead neurotoxicity.
authors.affiliation: The Institute of Medicine, Qiqihar Medical University, Qiqihar 161006, China.
authors.forename: Chengchong
authors.initials: C
authors.lastname: Li
authors.affiliation: Center for New Medicine Research, Changchun University of Chinese Medicine, Changchun 130117, China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Pan
authors.affiliation: The Institute of Medicine, Qiqihar Medical University, Qiqihar 161006, China.
authors.forename: Tianjiao
authors.initials: T
authors.lastname: Xu
authors.affiliation: Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, Yinchuan 750004, China.
authors.forename: Chun
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Medical Technology Department, Qiqihar Medical University, Qiqihar 161006, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wu
authors.affiliation: The Institute of Medicine, Qiqihar Medical University, Qiqihar 161006, China. Electronic address: nyc1968@126.com.
authors.forename: Yingcai
authors.initials: Y
authors.lastname: Niu
mesh_terms: D000818:Animals; D051381:Rats; D000975:Antioxidants / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D005978:Glutathione / Q000096:biosynthesis; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D007529:Isoflavones / Q000494:pharmacology; D015227:Lipid Peroxidation; D009942:Organometallic Compounds / Q000633:toxicity; D018384:Oxidative Stress / Q000187:drug effects; D016716:PC12 Cells; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D017382:Reactive Oxygen Species; D015398:Signal Transduction; D015854:Up-Regulation; D051267:NF-E2-Related Factor 2 / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005978:Glutathione; D038362:Glycogen Synthase Kinase 3; D007529:Isoflavones; C008261:lead acetate; D009942:Organometallic Compounds; D058539:Phosphatidylinositol 3-Kinase; D051057:Proto-Oncogene Proteins c-akt; C033607:puerarin; D017382:Reactive Oxygen Species; D051267:NF-E2-Related Factor 2
keywords: Glutathione; Glycogen synthase kinase 3β; Lead toxicity; Oxidative stress; Puerarin