Rosiglitazone reduces glucose-induced oxidative stress mediated by NAD(P)H oxidase via AMPK-dependent mechanism.
OBJECTIVE
Hyperglycemia is the main determinant of long-term diabetic complications, mainly through induction of oxidative stress. NAD(P)H oxidase is a major source of glucose-induced oxidative stress. In this study, we tested the hypothesis that rosiglitazone (RSG) is able to quench oxidative stress initiated by high glucose through prevention of NAD(P)H oxidase activation.


RESULTS
Intracellular ROS were measured using the fluoroprobe TEMPO-9-AC in HUVECs exposed to control (5 mmol/L) and moderately high (10 mmol/L) glucose concentrations. NAD(P)H oxidase and AMPK activities were determined by Western blot. We found that 10 mmol/L glucose increased significantly ROS production in comparison with 5 mmol/L glucose, and that this effect was completely abolished by RSG. Interestingly, inhibition of AMPK, but not PPARgamma, prevented this effect of RSG. AMPK phosphorylation by RSG was necessary for its ability to hamper NAD(P)H oxidase activation, which was indispensable for glucose-induced oxidative stress. Downstream of AMPK activation, RSG exerts antioxidative effects by inhibiting PKC.


CONCLUSIONS
This study demonstrates that RSG activates AMPK which, in turn, prevents hyperactivity of NAD(P)H oxidase induced by high glucose, possibly through PKC inhibition. Therefore, RSG protects endothelial cells against glucose-induced oxidative stress with an AMPK-dependent and a PPARgamma-independent mechanism.
Ceolotto
Giulio
G
Department of Clinical and Experimental Medicine, University of Padova, Via Giustiniani 2 35128 Padova, Italy. angelo.avogaro@unipd.it.
Gallo
Alessandra
A
Papparella
Italia
I
Franco
Lorenzo
L
Murphy
Ellen
E
Iori
Elisabetta
E
Pagnin
Elisa
E
Fadini
Gian Paolo
GP
Albiero
Mattia
M
Semplicini
Andrea
A
Avogaro
Angelo
A
D055372:AMP-Activated Protein Kinases; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D004789:Enzyme Activation; D020536:Enzyme Activators / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects*; D047495:PPAR gamma / Q000187:drug effects / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D000077154:Rosiglitazone; D015398:Signal Transduction / Q000187:drug effects*; D045162:Thiazolidinediones / Q000494:pharmacology*; D014162:Transfection; D020830:rac1 GTP-Binding Protein / Q000378:metabolism
D000975:Antioxidants; D020536:Enzyme Activators; D004791:Enzyme Inhibitors; D008562:Membrane Glycoproteins; D009097:Multienzyme Complexes; D047495:PPAR gamma; D010750:Phosphoproteins; D047428:Protein Kinase Inhibitors; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D045162:Thiazolidinediones; C079789:neutrophil cytosol factor 67K; D000077154:Rosiglitazone; C056558:CYBB protein, human; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; C086986:CYBA protein, human; C060505:neutrophil cytosolic factor 1; D017346:Protein Serine-Threonine Kinases; D011493:Protein Kinase C; D055372:AMP-Activated Protein Kinases; D020830:rac1 GTP-Binding Protein; D005947:Glucose