title: Rat liver epithelial cells express functional cytochrome P450 2E1.
abstract: Rat liver epithelial cells (RLECs) isolated by trypsinization of the livers of normal 10 day old rats are largely used in co-culture with primary hepatocytes. The aim of the present study was to investigate the expression of biotransformation enzyme-encoding genes in three preparations of RLEC lines. Although no expression of cytochrome P450 1A1/2 (CYP1A1/2), CYP2B1/2, CYP2C6 or CYP3A mRNAs could be detected, we found that all of the different preparations of RLECs expressed a high level of CYP2E1 mRNA. We demonstrated the presence of the CYP2E1 apoprotein in microsomes of RLECs by immunoblot analyses, together with chlorzoxazone 6-hydroxylation, an activity known to be mainly catalyzed by CYP2E1. In addition, acetone treatment of these cells resulted in an increase in both CYP2E1 apoprotein and chlorzoxazone 6-hydroxylation activity levels. Finally, we showed the susceptibility of RLECs to N-methyl formamide- and diethylnitrosamine-induced toxicity, suggesting metabolic activation by CYP2E1. Thus, RLECs may cooperate with hepatocytes to CYP2E1-mediated metabolism in the co-culture model. In addition, transfection experiments with a CYP2E1 promoter construct, in which the proximal 539 bp containing the binding site for HNF1alpha were inserted upstream of the chloramphenicol acetyl transferase gene, demonstrated a strong induction upon co-transfection with an HNF1alpha expression plasmid. Thus, RLECs provide a useful tool for studying metabolism and cytotoxicity of CYP2E1 substrates in the absence of other expressed CYPs, and for analyzing CYP2E1 promoter function.
authors.affiliation: INSERM U49, CHRU Pontchaillou, Rennes, France.
authors.forename: C
authors.initials: C
authors.lastname: Lerche
authors.forename: C
authors.initials: C
authors.lastname: Le Jossic
authors.forename: A
authors.initials: A
authors.lastname: Fautrel
authors.forename: I
authors.initials: I
authors.lastname: de Waziers
authors.forename: F
authors.initials: F
authors.lastname: Ballet
authors.forename: A
authors.initials: A
authors.lastname: Guillouzo
authors.forename: L
authors.initials: L
authors.lastname: Corcos
mesh_terms: D000818:Animals; D015153:Blotting, Western; D019392:Cytochrome P-450 CYP2E1; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D004848:Epithelium / Q000201:enzymology; D008099:Liver / Q000201:enzymology*; D008297:Male; D010089:Oxidoreductases, N-Demethylating / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011916:Rats, Inbred F344; D017207:Rats, Sprague-Dawley
chemical_list: D012333:RNA, Messenger; D003577:Cytochrome P-450 Enzyme System; D019392:Cytochrome P-450 CYP2E1; D010089:Oxidoreductases, N-Demethylating