Nox4 and nox2 NADPH oxidases mediate distinct cellular redox signaling responses to agonist stimulation.
OBJECTIVE
The NADPH oxidase isoforms Nox2 and Nox4 are coexpressed in many cell types and are implicated in agonist-stimulated redox-sensitive signal transduction. We compared the involvement of Nox2 versus Nox4 in redox-sensitive protein kinase activation after agonist stimulation.


RESULTS
We transfected HEK293 cells with Nox2 or Nox4 and compared ROS production and activation of mitogen activated protein kinases (MAPKs), Akt, and GSK3beta after acute agonist stimulation. Nox4 overexpression substantially increased basal ROS generation whereas ROS generation in response to angiotensin II and tumor necrosis factor (TNF)alpha was enhanced in Nox2-overexpressing cells. Nox4 overexpression induced basal activation of ERK1/2 and JNK whereas Nox2-transfected cells showed a modest increase in p38MAPK activation. After angiotensin II or TNFalpha treatment, JNK activation was augmented in Nox2 but not Nox4-transfected cells, whereas insulin augmented phosphorylation of p38MAPK, Akt, and GSK3beta specifically in Nox4-overexpressing cells and JNK specifically in Nox2-overexpressing cells.


CONCLUSIONS
These data indicate that Nox2 and Nox4 exhibit distinctive patterns of acute activation by angiotensin II, TNFalpha, and insulin and regulate the activation of distinct protein kinases.
Anilkumar
Narayana
N
Department of Cardiology, The James Black Centre, King's College London, 125 Coldharbour Lane, London SE59NU, UK.
Weber
Roberta
R
Zhang
Min
M
Brewer
Alison
A
Shah
Ajay M
AM
D000804:Angiotensin II / Q000378:metabolism*; D000818:Animals; D000906:Antibodies; D019556:COS Cells; D002374:Catalase / Q000494:pharmacology; D002522:Chlorocebus aethiops; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology*; D004789:Enzyme Activation; D016166:Free Radical Scavengers / Q000494:pharmacology; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D000074662:NADPH Oxidase 2; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000172:deficiency / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D010084:Oxidation-Reduction; D010766:Phosphorylation; D011092:Polyethylene Glycols / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013482:Superoxide Dismutase / Q000494:pharmacology; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D000906:Antibodies; D016166:Free Radical Scavengers; D007328:Insulin; D008562:Membrane Glycoproteins; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; C070295:catalase-polyethylene glycol; D000804:Angiotensin II; D011092:Polyethylene Glycols; D002374:Catalase; D013482:Superoxide Dismutase; C063471:polyethylene glycol-superoxide dismutase; C056558:CYBB protein, human; C488842:Cybb protein, mouse; D000074662:NADPH Oxidase 2; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C422943:Nox4 protein, mouse; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases; D038362:Glycogen Synthase Kinase 3