HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 287/4/F665    most recent 00034.2004v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (9) Citing Articles via Google Scholar Google Scholar Articles by Lee, H. S. Articles by Hong, H. K. Search for Related Content PubMed PubMed Citation Articles by Lee, H. S. Articles by Hong, H. K.

Glycated albumin activates PAI-1 transcription through Smad DNA binding sites in mesangial cells

Department of Pathology, Seoul National University College of Medicine, Seoul 110-799, Korea

Submitted 4 February 2004 ; accepted in final form 5 June 2004

Amadori-modified glycated albumin stimulates extracellular matrix and transforming growth factor- (TGF-) expression in cultured mesangial cells. Smad proteins transduce the TGF--mediated signal, and Smad-binding CAGA sequences are present in the plasminogen activator inhibitor-1 (PAI-1) promoter. This study examined whether glycated albumin induces PAI-1 transcription in human mesangial cells (HMC) through Smad-binding sites in the PAI-1 promoter. Quiescent HMC were exposed to 200 µg/ml bovine serum albumin (BSA) or glycated BSA (Gly-BSA) for 12–72 h. At 24 h, Gly-BSA stimulated TGF-₁ and PAI-1 mRNA expression in HMC to 1.8 and 3.2 times that in the BSA-treated control cells. Gly-BSA also activated the PAI-1 promoter luciferase activity 2.3-fold. Gly-BSA-treated cells enhanced Smad2 and Smad3 protein levels 2.5 times the control levels in the nuclei. An electrophoretic mobility shift assay performed using CAGA sequences as a probe showed that Gly-BSA increased DNA/protein complexes. When nuclear extracts were preincubated with 100-fold molar excess of unlabeled CAGA oligonucleotide, the formation of complex was prevented. The DNA-binding protein was shown to be Smad3 by antibody supershift. Transfection of phosphorothioate CAGA oligonucleotide, a CAGA antisense analog, inhibited Gly-BSA-induced PAI-1 mRNA expression. Cotransfection of phosphorothioate CAGA oligonucleotides with PAI-1 reporter vector also blocked Gly-BSA-induced PAI-1 promoter luciferase activity. These results indicate that Gly-BSA increases DNA binding activity of Smad3 and that it stimulates PAI-1 transcription through Smad-binding CAGA sequences in the PAI-1 promoter in HMC. Thus progression of diabetic nephropathy may be promoted by PAI-1 upregulation mediated by the glycated albumin-induced Smad/DNA interactions.

Amadori adducts; extracellular matrix; CAGA boxes; diabetic nephropathy

This article has been cited by other articles:

				X. Yu, C. Li, X. Li, and L. Cai Rosiglitazone Prevents Advanced Glycation End Products-Induced Renal Toxicity Likely through Suppression of Plasminogen Activator Inhibitor-1 Toxicol. Sci., April 1, 2007; 96(2): 346 - 356. [Abstract] [Full Text] [PDF]

				G. Giannico, P. Cortes, M. H. Baccora, C. Hassett, D. W. Taube, and J. Yee Glibenclamide prevents increased extracellular matrix formation induced by high glucose concentration in mesangial cells Am J Physiol Renal Physiol, January 1, 2007; 292(1): F57 - F65. [Abstract] [Full Text] [PDF]