Hepatocyte-protective effect of nectandrin B, a nutmeg lignan, against oxidative stress: Role of Nrf2 activation through ERK phosphorylation and AMPK-dependent inhibition of GSK-3β

Journal Article · Thu Sep 15 00:00:00 EDT 2016 · Toxicology and Applied Pharmacology

DOI:https://doi.org/10.1016/J.TAAP.2016.08.003· OSTI ID:22690797

Song, Jae-Sook; Kim, Eun-Kyung; Choi, Yong-Won ^[1]; Oh, Won Keun ^[2]; Kim, Young-Mi ^[1]

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1. Department of Pharmacy, College of Pharmacy and Institute of Pharmaceutical Science and Technology, Hanyang University, Ansan, Gyeonggi-do 15588 (Korea, Republic of)
2. College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University (Korea, Republic of)

Oxidative stress can contribute to the development and progression of liver diseases, such as drug-induced or alcoholic liver injury, nonalcoholic fatty liver disease, and nonalcoholic steatohepatitis. Nectandrin B is a bioactive lignan isolated from nutmeg extract. To date, little information is available about its pharmacological activities in the liver. This study investigated the hepatocyte-protective effect of nectandrin B against tert-butylhydroperoxide-induced oxidative injury and the underlying molecular mechanism. The cell viability assay revealed that nectandrin B prevents apoptosis stimulated by tert-butylhydroperoxide in both HepG2 cells and primary mouse hepatocytes. Nectandrin B also attenuated ROS production and restored the depleted glutathione level. Real-time PCR and immunoblot analyses showed that the expression of glutamate-cysteine ligase, an enzyme responsible for the glutathione biosynthesis, was induced by nectandrin B, indicating its indirect antioxidative effect. The NF-E2-related factor-2 (Nrf2) regulates gene expression of an array of antioxidant enzymes in hepatocytes. Nectandrin B stimulated Nrf2 activation as evidenced by its enhanced nuclear accumulation and increased antioxidant response element (ARE)-luciferase activity. Intriguingly, the hepatocyte-protective effect of nectandrin B against oxidative damage was completely abrogated by Nrf2 knockdown using Nrf2 specific siRNA. Nectandrin B promoted ERK activation, but inactivated GSK-3β through the AMPK-mediated inhibitory phosphorylation. The enforced overexpression of dominant-negative mutant of MEK1 or AMPKα, or wild-type GSK-3β inhibited the increase in the NQO1-ARE-luciferase activity stimulated by nectandrin B, suggesting that both ERK and AMPK-GSK-3β signalings are involved in the activation of Nrf2/ARE pathway by nectandrin B. Consistent with this, cytoprotection and restoration of glutathione level by nectandrin B was also blocked by the overexpression of dominant-negative MEK1 or wild-type GSK-3β. Finally, our data demonstrate that nectandrin B has the ability to protect hepatocytes against oxidative injury through the activation of Nrf2/ARE pathway mediated by ERK phosphorylation and AMPK-dependent inactivation of GSK-3β. - Highlight: • Nectandrin B, a nutmeg lignan protects hepatocytes against oxidative damage. • Nectandrin B exerts an indirect antioxidative effect via the activation of Nrf2. • Both ERK and GSK-3β pathways contribute to the activation of Nrf2 and hepatocyte-protection by nectandrin B. • Nectandrin B can inactivate GSK-3β through the activation of AMPK in HepG2 cells.

• OSTI ID: 22690797
• Journal Information: Toxicology and Applied Pharmacology, Vol. 307; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0041-008X
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
ADP
AMP
ANTIOXIDANTS
APOPTOSIS
BENZOQUINONES
BIOSYNTHESIS
CALMODULIN
CYSTEINE
ECR HEATING
GLUTATHIONE
GLYCOGEN
HEMAGGLUTININS
HEME
INACTIVATION
INHIBITION
INJURIES
LIGASES
LIVER
LIVER CELLS
LUCIFERASE
MICE
MITOGENS
NAD
OXIDATION
OXYGENASES
PHOSPHORYLATION
POLYMERASE CHAIN REACTION
RIBOSE
SAFETY