Cytochrome P450 2E1-derived reactive oxygen species mediate paracrine stimulation of collagen I protein synthesis by hepatic stellate cells.
To evaluate possible fibrogenic effects of CYP2E1-dependent generation of reactive oxygen species, a model was developed using co-cultures of HepG2 cells, which do (E47 cells) or do not (C34 cells) express cytochrome P450 2E1 (CYP2E1) with stellate cells. There was an increase in intra- and extracellular H(2)O(2), lipid peroxidation, and collagen type I protein in stellate cells co-cultured with E47 cells compared with stellate cells alone or co-cultured with C34 cells. The increase in collagen was prevented by antioxidants and a CYP2E1 inhibitor. CYP3A4 did not mimic the stimulatory effects found with CYP2E1. Collagen mRNA levels remained unchanged, and pulse-chase analysis indicated similar half-lives of collagen I protein between both co-cultures. However, collagen protein synthesis was increased in E47 co-culture. Hepatocytes from pyrazole-treated rats (with high levels of CYP2E1) induced collagen protein in primary stellate cells, and antioxidants and CYP2E1 inhibitors blocked this effect. These results suggest that increased translation of collagen mRNA by CYP2E1-derived reactive oxygen species is responsible for the increase in collagen protein produced by the E47 co-culture. These co-culture models may be useful for understanding the impact of CYP2E1-derived ROS on stellate cell function and activation.
Nieto
Natalia
N
Department of Pharmacology and Biological Chemistry, Mount Sinai School of Medicine, New York, New York 10029, USA.
Friedman
Scott L
SL
Cederbaum
Arthur I
AI
D000818:Animals; D000975:Antioxidants / Q000378:metabolism / Q000494:pharmacology; D002460:Cell Line; D002478:Cells, Cultured; D018920:Coculture Techniques; D003094:Collagen / Q000378:metabolism; D024042:Collagen Type I / Q000096:biosynthesis*; D019392:Cytochrome P-450 CYP2E1 / Q000378:metabolism*; D018076:DNA, Complementary / Q000378:metabolism; D022781:Hepatocytes / Q000378:metabolism*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology; D015227:Lipid Peroxidation; D018384:Oxidative Stress; D019899:Paracrine Communication; D011485:Protein Binding; D011720:Pyrazoles / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017382:Reactive Oxygen Species; D013997:Time Factors; D014407:Tumor Cells, Cultured
D000975:Antioxidants; D024042:Collagen Type I; D018076:DNA, Complementary; D011720:Pyrazoles; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; C031280:pyrazole; D003094:Collagen; D006861:Hydrogen Peroxide; D019392:Cytochrome P-450 CYP2E1