title: Neuroprotection against 6-OHDA-induced oxidative stress and apoptosis in SH-SY5Y cells by 5,7-Dihydroxychromone: Activation of the Nrf2/ARE pathway.
abstract: OBJECTIVE
  The aim of this study was to prove the neuroprotective effect of 5,7-Dihydroxychromone (DHC) through the Nrf2/ARE signaling pathway. To elucidate the mechanism, we investigated whether 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in SH-SY5Y cells could be attenuated by DHC via activating the Nrf2/ARE signal and whether DHC could down-regulate 6-OHDA-induced excessive ROS generation
  
  
  METHODS
  To evaluate the neuroprotective effect of DHC against 6-OHDA-induced apoptosis, FACS analysis was performed using PI staining. The inhibitory effect of DHC against 6-OHDA-induced ROS generation was evaluated by DCFH-DA staining assay. Additionally, translocation of Nrf2 to the nucleus and increased Nrf2/ARE binding activity, which subsequently resulted in the up-regulation of the Nrf2-dependent antioxidant gene expressions including HO-1, NQO1, and GCLc, were evaluated by Western blotting and EMSA.
  
  
  RESULTS
  Pre-treatment of DHC, one of the constituents of Cudrania tricuspidata, significantly protects 6-OHDA-induced neuronal cell death and ROS generation. Also, DHC inhibited the expression of activated caspase-3 and caspase-9 and cleaved PARP in 6-OHDA-induced SH-SY5Y cells. DHC induced the translocation of Nrf2 to the nucleus and increased Nrf2/ARE binding activity which results in the up-regulation of the expression of Nrf2-dependent antioxidant genes, including HO-1, NQO1, and GCLc. The addition of Nrf2 siRNA abolished the neuroprotective effect of DHC against 6-OHDA-induced neurotoxicity and the expression of Nrf2-mediated antioxidant genes.
  
  
  CONCLUSIONS
  Activation of Nrf2/ARE signal by DHC exerted neuroprotective effects against 6-OHDA-induced oxidative stress and apoptosis. This finding will give an insight that activating Nrf2/ARE signal could be a new potential therapeutic strategy for neurodegenerative disease.
authors.affiliation: Natural Products Research Institute, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea.
authors.forename: Dong-Woo
authors.initials: DW
authors.lastname: Kim
authors.affiliation: Division of Wood Chemistry & Microbiology, Department of Forest Products, Korea Forest Research Institute, Seoul 130-712, Republic of Korea.
authors.forename: Kyoung-Tae
authors.initials: KT
authors.lastname: Lee
authors.affiliation: Department of Biosystems and Biotechnology, Korea University, Seoul 136-713, Republic of Korea.
authors.forename: Jaeyoung
authors.initials: J
authors.lastname: Kwon
authors.affiliation: Division of Wood Chemistry & Microbiology, Department of Forest Products, Korea Forest Research Institute, Seoul 130-712, Republic of Korea.
authors.forename: Hak Ju
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: Department of Biosystems and Biotechnology, Korea University, Seoul 136-713, Republic of Korea. Electronic address: dongholee@korea.ac.kr.
authors.forename: Dongho
authors.initials: D
authors.lastname: Lee
authors.affiliation: Natural Products Research Institute, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea. Electronic address: mars@snu.ac.kr.
authors.forename: Woongchon
authors.initials: W
authors.lastname: Mar
mesh_terms: D061745:Antioxidant Response Elements / Q000187:drug effects; D000975:Antioxidants / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D002867:Chromones / Q000302:isolation & purification / Q000494:pharmacology*; D015536:Down-Regulation / Q000187:drug effects; D006801:Humans; D029586:Moraceae / Q000737:chemistry*; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D009447:Neuroblastoma / Q000378:metabolism; D018696:Neuroprotective Agents / Q000302:isolation & purification / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects*; D016627:Oxidopamine / Q000633:toxicity; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000975:Antioxidants; D002867:Chromones; D051267:NF-E2-Related Factor 2; D018696:Neuroprotective Agents; D017382:Reactive Oxygen Species; C080094:5,7-dihydroxychromone; D016627:Oxidopamine
keywords: 5,7-Dihydroxychromone; 6-OHDA; Cudrania tricuspidata; Neuroprotection; Nrf2/ARE pathway; Oxidative stress