Document Detail


Critical role of Nox4-based NADPH oxidase in glucose-induced oxidative stress in the kidney: implications in type 2 diabetic nephropathy.
MedLine Citation:
PMID:  20630933     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Molecular mechanisms underlying renal complications of diabetes remain unclear. We tested whether renal NADPH oxidase (Nox) 4 contributes to increased reactive oxygen species (ROS) generation and hyperactivation of redox-sensitive signaling pathways in diabetic nephropathy. Diabetic mice (db/db) (20 wk) and cultured mouse proximal tubule (MPT) cells exposed to high glucose (25 mmol/l, D-glucose) were studied. Expression (gene and protein) of Nox4, p22(phox), and p47(phox), but not Nox1 or Nox2, was increased in kidney cortex, but not medulla, from db/db vs. control mice (db/m) (P < 0.05). ROS generation, p38 mitogen-activated protein (MAP) kinase phosphorylation, and content of fibronectin and transforming growth factor (TGF)-β1/2 were increased in db/db vs. db/m (P < 0.01). High glucose increased expression of Nox4, but not other Noxes vs. normal glucose (P < 0.05). This was associated with increased NADPH oxidase activation and enhanced ROS production. Nox4 downregulation by small-interfering RNA and inhibition of Nox4 activity by GK-136901 (Nox1/4 inhibitor) attenuated d-glucose-induced NADPH oxidase-derived ROS generation. High d-glucose, but not l-glucose, stimulated phosphorylation of p38MAP kinase and increased expression of TGF-β1/2 and fibronectin, effects that were inhibited by SB-203580 (p38MAP kinase inhibitor). GK-136901 inhibited d-glucose-induced actions. Our data indicate that, in diabetic conditions: 1) renal Nox4 is upregulated in a cortex-specific manner, 2) MPT cells possess functionally active Nox4-based NADPH, 3) Nox4 is a major source of renal ROS, and 4) activation of profibrotic processes is mediated via Nox4-sensitive, p38MAP kinase-dependent pathways. These findings implicate Nox4-based NADPH oxidase in molecular mechanisms underlying fibrosis in type 2 diabetic nephropathy.
Authors:
M Sedeek; G Callera; A Montezano; A Gutsol; F Heitz; C Szyndralewiez; P Page; C R J Kennedy; K D Burns; R M Touyz; R L Hébert
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-07-14
Journal Detail:
Title:  American journal of physiology. Renal physiology     Volume:  299     ISSN:  1522-1466     ISO Abbreviation:  Am. J. Physiol. Renal Physiol.     Publication Date:  2010 Dec 
Date Detail:
Created Date:  2010-12-08     Completed Date:  2011-01-10     Revised Date:  2011-04-28    
Medline Journal Info:
Nlm Unique ID:  100901990     Medline TA:  Am J Physiol Renal Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  F1348-58     Citation Subset:  IM    
Affiliation:
Kidney Research Centre, Ottawa Hospital Research Institute and Deptartment of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cells, Cultured
Cytochrome b Group / biosynthesis
Diabetes Mellitus, Experimental / metabolism*,  pathology
Diabetic Nephropathies / metabolism*,  pathology
Fibrosis
Glucose / pharmacology
Kidney / metabolism*
Male
Mice
NADPH Oxidase / biosynthesis,  physiology*
Oxidative Stress / drug effects
Pyrazoles / pharmacology
Pyridones / pharmacology
RNA, Small Interfering / pharmacology
Reactive Oxygen Species / metabolism
p38 Mitogen-Activated Protein Kinases / drug effects
Grant Support
ID/Acronym/Agency:
//Canadian Institutes of Health Research
Chemical
Reg. No./Substance:
0/2-(2-chlorophenyl)-4-methyl-5-(pyridin-2-ylmethyl)-1H-pyrazolo(4,3-c)pyridine-3,6(2H,5H)-dione; 0/Cytochrome b Group; 0/Pyrazoles; 0/Pyridones; 0/RNA, Small Interfering; 0/Reactive Oxygen Species; 50-99-7/Glucose; EC 1.6.-/Nox4 protein, mouse; EC 1.6.3.1/NADPH Oxidase; EC 1.6.3.1/neutrophil cytosolic factor 1; EC 1.6.3.1/p22(phox) protein, mouse; EC 2.7.11.24/p38 Mitogen-Activated Protein Kinases

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