Dong-Woo Kim1, Kyoung-Tae Lee2, Jaeyoung Kwon3, Hak Ju Lee2, Dongho Lee4, Woongchon Mar5. 1. Natural Products Research Institute, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea. 2. Division of Wood Chemistry & Microbiology, Department of Forest Products, Korea Forest Research Institute, Seoul 130-712, Republic of Korea. 3. Department of Biosystems and Biotechnology, Korea University, Seoul 136-713, Republic of Korea. 4. Department of Biosystems and Biotechnology, Korea University, Seoul 136-713, Republic of Korea. Electronic address: dongholee@korea.ac.kr. 5. Natural Products Research Institute, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea. Electronic address: mars@snu.ac.kr.
Abstract
AIMS: 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 MAIN 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. KEY FINDINGS: 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. SIGNIFICANCE: 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.
AIMS: 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 MAIN 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. KEY FINDINGS: 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. SIGNIFICANCE: 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.