Role of reactive oxygen species generated by NADPH oxidase in the mechanism of activation of K+-Cl--cotransport by N-ethylmaleimide in HepG2 human hepatoma cells

Authors
Citation
Ja. Kim et Ys. Lee, Role of reactive oxygen species generated by NADPH oxidase in the mechanism of activation of K+-Cl--cotransport by N-ethylmaleimide in HepG2 human hepatoma cells, FREE RAD RE, 35(1), 2001, pp. 43-53
Citations number
52
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biochemistry & Biophysics
Journal title
FREE RADICAL RESEARCH
ISSN journal
1071-5762 → ACNP
Volume
35
Issue
1
Year of publication
2001
Pages
43 - 53
Database
ISI
SICI code
1071-5762(2001)35:1<43:ROROSG>2.0.ZU;2-G
Abstract
K+-Cl--cotransport (KCC) is ubiquitously present in all cells, and plays an essential role in ion and volume regulation. In this study we investigated the role of reactive oxygen species (ROS) in regulation of KCC in HepG2 hu man hepatoblastoma cells. N-ethylmaleimide (NEM), a KCC activator, induced Cl--dependent K+ efflux, which was markedly prevented by KCC inhibitors (ca lyculin-A, genistein and BaCl2), indicating that KCC is activated by NEM in the HepG2 cells. Treatment with NEM also induced a sustained increase in t he level of intracellular ROS assessed by 2',7'-dichlorofluorescein floures cence. Antioxidants, N-acetyl cysteine or N,N'-diphenyl-p-phenylenediamine significantly inhibited both ROS generation and KCC activation induced by N EM. The NEM-induced ROS production was significantly suppressed by inhibito rs of NADPH oxidase (diphenylene iodonium, apocynin and neopterine). These inhibitors also significantly inhibited the NEM-induced KCC activation. Tak en together, these results suggest that ROS generated by NADPH oxidase may mediate the NEM-induced activation of KCC in human hepatoma cells.