Molecular and Cellular Biochemistry

, Volume 350, Issue 1, pp 237–250

Schisandrin B elicits a glutathione antioxidant response and protects against apoptosis via the redox-sensitive ERK/Nrf2 pathway in H9c2 cells

  • Po Yee Chiu
  • Na Chen
  • Po Kuan Leong
  • Hoi Yan Leung
  • Kam Ming Ko
Article

DOI: 10.1007/s11010-010-0703-3

Cite this article as:
Chiu, P.Y., Chen, N., Leong, P.K. et al. Mol Cell Biochem (2011) 350: 237. doi:10.1007/s11010-010-0703-3

Abstract

This study investigated the signal transduction pathway involved in the cytoprotective action of (−)schisandrin B [(−)Sch B, a stereoisomer of Sch B]. Using H9c2 cells, the authors examined the effects of (−)Sch B on MAPK and Nrf2 activation, as well as the subsequent eliciting of glutathione response and protection against apoptosis. Pharmacological tools, such as cytochrome P-450 (CYP) inhibitor, antioxidant, MAPK inhibitor, and Nrf2 RNAi, were used to delineate the signaling pathway. (−)Sch B caused a time-dependent activation of MAPK in H9c2 cells, with the degree of ERK activation being much larger than that of p38 or JNK. The MAPK activation was followed by an increase in the level of nuclear Nrf2, an indirect measure of Nrf2 activation, and the eliciting of a glutathione antioxidant response. The activation of MAPK and Nrf2 seemed to involve oxidants generated from a CYP-catalyzed reaction with (−)Sch B. Both ERK inhibition by U0126 and Nrf2 suppression by Nrf2 RNAi transfection largely abolished the cytoprotection against hypoxia/reoxygenation-induced apoptosis in (−)Sch B-pretreated cells. (−)Sch B pretreatment potentiated the reoxygenation-induced ERK activation, whereas both p38 and JNK activations were suppressed. Under the condition of ERK inhibition, Sch B treatment did not protect against ischemia/reperfusion injury in an ex vivo rat heart model. The results indicate that (−)Sch B triggers a redox-sensitive ERK/Nrf2 signaling, which then elicits a cellular glutathione antioxidant response and protects against hypoxia/reoxygenation-induced apoptosis in H9c2 cells. The ERK-mediated signaling is also likely involved in the cardioprotection afforded by Sch B in vivo.

Keywords

Schisandrin BERKNrf2Glutathione antioxidant systemHypoxia/reoxygenationApoptosisH9c2

Abbreviations

ABT

1-Amino-benzotriazole

AIF

Apoptosis inducing factor

CYP

Cytochrome P-450

DMTU

Dimethylthiouracil

DTT

Dithiothreitol

EpRE

Electrophile response element

ERK

Extracellular signal-regulated protein kinase

GCL

γ-Glutamyl cysteine ligase

G6PDH

Glucose-6-phosphate dehydrogenase

GR

Glutathione reductase

GSH

Reduced glutathione

JNK

C-jun-NH2-terminal kinases

LDH

Lactate dehydrogenase

MAPK

Mitogen-activated protein kinases

mGCL

Modulatory subunit of GCL

Nrf2

Nuclear factor erythroid 2-related factor 2

p38

p38 MAPK

PMSF

Phenylmethylsulphonyl fluoride

ROS

Reactive oxygen species

Sch B

Schisandrin B

SDS

Sodium docecyl sulfate

Trx

Thioredoxin-1

Copyright information

© Springer Science+Business Media, LLC. 2010

Authors and Affiliations

  • Po Yee Chiu
    • 1
  • Na Chen
    • 1
  • Po Kuan Leong
    • 1
  • Hoi Yan Leung
    • 1
  • Kam Ming Ko
    • 1
  1. 1.Section of Biochemistry and Cell Biology, Division of Life ScienceThe Hong Kong University of Science and TechnologyHong Kong SARChina