Low- and high-dose hydrogen peroxide regulation of transcription factor NF-E2-related factor 2.
BACKGROUND
Reactive oxygen species (ROS) may play both physiological and pathophysiological roles. Transcription factor NF-E2-related factor 2 (Nrf2) regulates antioxidant response element (ARE)-mediated genes expression and coordinates induction of chemoprotective proteins in response to physical and chemical stresses. The exact role of Nrf2 in cellular responses to different levels of oxidative stresses remains unknown.


METHODS
Rat pulmonary microvascular endothelial cells were cultured and treated with 0 mmol/L, 0.125 mmol/L, 0.25 mmol/L, 0.5 mmol/L, 1.0 mmol/L and 2.0 mmol/L hydrogen peroxide solution for 2 hours. Nrf2 gene expression was assayed by reverse transcription-PCR, Nrf2-ARE binding activity was assayed with electrophoretic mobility shift assay (EMSA), and localization of Nrf2 was detected with immunohistochemistry.


RESULTS
Low and moderate (0.125 mmol/L, 0.25 mmol/L and 0.5 mmol/L) doses hydrogen peroxide exposure of rat pulmonary microvascular endothelial cells led to the nuclear accumulation of Nrf2, increased activity of transcription regulation and up-regulation of ARE-medicated gene expression. In contrast, high doses of hydrogen peroxide (1 mmol/L, 2 mmol/L) exposure of the cells led to the nuclear exclusion of Nrf2, decreased activity transcription regulation and down-regulation of ARE-mediated gene expression.


CONCLUSIONS
Low and moderate doses of hydrogen peroxide play protective roles by increasing transcription activity of Nrf2, whereas high- dose hydrogen peroxide plays a deleterious role by decreasing transcription activity of Nrf2.
Ning
Jiao-lin
JL
Department of Anesthesia, Southwest Hospital, Third Military Medical University, Chongqing, China.
Mo
Li-wen
LW
Lai
Xi-nan
XN
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects; D002478:Cells, Cultured; D024202:Electrophoretic Mobility Shift Assay; D015870:Gene Expression / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007150:Immunohistochemistry; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction
D051267:NF-E2-Related Factor 2; D006861:Hydrogen Peroxide