Regulation of PKM2 and Nrf2-ARE pathway during benzoquinone induced oxidative stress in yolk sac hematopoietic stem cells.

Jie Zhu,Yongyi Bi,Liping Wang,Shaozun Zhang,Tan Yang,Zhuoyue Bi,Wenting Huang,Wentao Song,Yanfeng Zhou,Hong Wang,Chunhong Wang,Ningna Fan,Yue Bai,Wei Wang,Zhen Li

doi:10.1371/journal.pone.0113733

Abstract

Benzene is an occupational toxicant and an environmental pollutant that is able to induce the production of reactive oxygen species (ROS), causing oxidative stress and damages of the macromolecules in target cells, such as the hematopoietic stem cells. We had previously found that embryonic yolk sac hematopoietic stem cells (YS-HSCs) are more sensitive to benzene toxicity than the adult bone marrow hematopoietic stem cells, and that nuclear factor-erythroid-2-related factor 2 (Nrf2) is the major regulator of cytoprotective responses to oxidative stress. In the present report, we investigated the effect of PKM2 and Nrf2-ARE pathway on the cellular antioxidant response to oxidative stress induced by benzene metabolite benzoquinone (BQ) in YS-HSC isolated from embryonic yolk sac and enriched by magnetic-activated cell sorting (MACS). Treatment of the YS-HSC with various concentrations of BQ for 6 hours induces ROS generation in a dose-dependent manner. Additional tests showed that BQ is also capable of inducing expression of NADPH oxidase1 (NOX1), and several other antioxidant enzymes or drug-metabolizing enzymes, including heme oxygenase 1 (HMOX1), superoxide dismutase (SOD), catalase and NAD(P)H dehydrogenase quinone 1 (NQO1). Concomitantly, only the expression of PKM2 protein was decreased by the treatment of BQ but not the PKM2 mRNA, which suggested that BQ may induce PKM2 degradation. Pretreatment of the cells with antioxidant N-acetylcysteine (NAC) decreased ROS generation and prevented BQ-induced PKM2 degradation, suggesting involvement of ROS in the PKM2 protein degradation in cellular response to BQ. These findings suggest that BQ is a potent inducer of ROS generation and the subsequent antioxidant responses of the YS-HSC. The accumulated ROS may attenuate the expression of PKM2, a key regulator of the pyruvate metabolism and glycolysis.

Highlights

reactive oxygen species (ROS) Regulate Pyruvate kinase M2 (PKM2) (NAC) decreased ROS generation and prevented BQ-induced PKM2 degradation, suggesting involvement of ROS in the PKM2 protein degradation in cellular response to BQ. These findings suggest that BQ is a potent inducer of ROS generation and the subsequent antioxidant responses of the yolk sac hematopoietic stem cells (YS-HSCs)
The present study was focused on the possible involvement of ROS generation and the activation of the anti-oxidant defense system in embryonic YS-HSCs treated with BQ
We provided evidence showing that BQ is highly capable of inducing ROS, along with an increased elevation of NADPH oxidase1 (NOX1) protein, nuclear accumulation of nuclear factor-erythroid-2-related factor 2 (Nrf2) and the activation of Nrf2-ARE pathway in YS-HSCs

Summary

Introduction

These findings suggest that BQ is a potent inducer of ROS generation and the subsequent antioxidant responses of the YS-HSC. The present study was focused on the possible involvement of ROS generation and the activation of the anti-oxidant defense system in embryonic YS-HSCs treated with BQ. We provided evidence showing that BQ is highly capable of inducing ROS, along with an increased elevation of NOX1 protein, nuclear accumulation of Nrf2 and the activation of Nrf2-ARE pathway in YS-HSCs. The expression of PKM2 protein was decreased by treatment of BQ.

Results

Conclusion