NF-kappaB-dependent genes induced by proteinuria and identified using DNA microarrays.
BACKGROUND
A close correlation has been shown between tubulointerstitial (TI) injury and the outcome of renal dysfunction, and nuclear factor-kappaB (NFkappaB) has been shown to play a key role in proteinuria-induced TI injury. To explore the molecular mechanisms of the proteinuria-induced TI injury further, we have analyzed renal gene expression with DNA microarrays, with and without specific inhibition of NF-kappaB in the proximal tubules.


METHODS
Unilaterally nephrectomized rats loaded with bovine serum albumin (BSA) were used as a model of proteinuric renal injury. Renal NF-kappaB activation was inhibited by gene transfer of the truncated form of IkappaBalpha (inhibitor of NF-kappaB) via the injection of a recombinant adenovirus vector into the renal artery, an method established in a previous study. Total RNA was extracted from the kidney and analyzed with a DNA microarrays containing 1081 genes.


RESULTS
Renal NF-kappaB activation and TI injury in BSA-loaded proteinuric rats were inhibited by the gene transfer of the truncated form of IkappaBalpha. DNA microarray analysis revealed 45 up-regulated genes and six down-regulated genes in the proteinuric rats, and expression of 23 of these 51 genes was significantly altered by NF-kappaB inhibition. Among these 23 genes, we focused on clusterin and confirmed the results of microarray analysis by Western blotting and PCR.


CONCLUSIONS
In this study, 23 genes of 51 proteinuria-related genes were regulated by NF-kappaB activation, suggesting that some of these genes may serve as target molecules for the treatment of progressive TI injury.
Takase
Osamu
O
Department of Internal Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
Marumo
Takeshi
T
Hishikawa
Keiichi
K
Fujita
Toshiro
T
Quigg
Richard J
RJ
Hayashi
Matsuhiko
M
D000818:Animals; D017209:Apoptosis; D051152:Clusterin / Q000235:genetics / Q000378:metabolism; D004247:DNA / Q000235:genetics; D004195:Disease Models, Animal; D005260:Female; D005786:Gene Expression Regulation; D020672:I-kappa B Proteins / Q000235:genetics; D020287:In Situ Nick-End Labeling; D016328:NF-kappa B / Q000235:genetics* / Q000378:metabolism*; D009392:Nephrectomy; D009395:Nephritis, Interstitial / Q000209:etiology / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D011507:Proteinuria / Q000150:complications / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D051152:Clusterin; C083487:I kappa B beta protein; D020672:I-kappa B Proteins; D016328:NF-kappa B; D004247:DNA