Cytochrome P450 2B1 mediates oxidant injury in puromycin-induced nephrotic syndrome.
BACKGROUND
Reactive oxygen metabolites (ROM) are important mediators of puromycin aminonucleoside (PAN) induced minimal change nephrotic syndrome (NS) in rats. We have recently shown that cytochrome P450 (CYP) is a significant source of catalytic iron in this model of glomerular injury. The current study was designed to identify the CYP isozyme(s) in the rat glomeruli and explore the role of the specific isozyme(s) in PAN-induced minimal change NS.


METHODS
NS was induced in rats by a single intravenous injection of PAN. Animals were sacrificed at different time points for variety of biochemical assays including Western blot, immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). Ultrastructural histochemistry was utilized to study hydrogen peroxide (H2O2) generation in the kidney.


RESULTS
Several CYP isozymes were tested and CYP2B1 was localized exclusively in the rat glomeruli but not in the tubules. Treatment with PAN resulted in the generation of H2O2 in the glomerular basement membrane with significant loss of CYP2B1 content accompanied by a marked increase in the catalytic iron. CYP2B1 inhibitors cimetidine and piperine significantly reduced H2O2 generation, and prevented the loss of CYP2B1 content and the increase in the catalytic iron. CYP2B1 inhibitors also provided significant protection against PAN induced proteinuria. The induction of heme oxygenase and ferritin also was observed in the glomeruli in PAN-treated rats. Both cimetidine and piperine reduced the up-regulation of these proteins.


CONCLUSIONS
Our data indicate that CYP2B1 plays an important role in PAN induced NS by serving as a site for ROM generation and a significant source of catalytic iron.
Liu
Hua
H
Department of Pediatrics, Division of Nephrology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216-4505, USA.
Bigler
Steven A
SA
Henegar
Jeffrey R
JR
Baliga
Radhakrishna
R
D000818:Animals; D000900:Anti-Bacterial Agents; D001189:Aryl Hydrocarbon Hydroxylases / Q000378:metabolism; D019362:Cytochrome P-450 CYP2B1 / Q000378:metabolism*; D019392:Cytochrome P-450 CYP2E1 / Q000378:metabolism; D051544:Cytochrome P-450 CYP3A; D042926:Cytochrome P-450 CYP4A; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D005293:Ferritins / Q000378:metabolism; D006419:Heme Oxygenase (Decyclizing) / Q000235:genetics / Q000378:metabolism; D051547:Heme Oxygenase-1; D008297:Male; D006899:Mixed Function Oxygenases / Q000378:metabolism; D009404:Nephrotic Syndrome / Q000139:chemically induced / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology*; D010089:Oxidoreductases, N-Demethylating / Q000378:metabolism; D011691:Puromycin; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism
D000900:Anti-Bacterial Agents; D017382:Reactive Oxygen Species; D011691:Puromycin; D005293:Ferritins; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D019392:Cytochrome P-450 CYP2E1; D001189:Aryl Hydrocarbon Hydroxylases; D019362:Cytochrome P-450 CYP2B1; D051544:Cytochrome P-450 CYP3A; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1; D042926:Cytochrome P-450 CYP4A; D010089:Oxidoreductases, N-Demethylating