title: Human CYP2E1 is regulated by miR-378.
abstract: Human CYP2E1 is one of the pharmacologically and toxicologically important cytochrome P450 isoforms. Earlier studies have reported that the CYP2E1 expression is extensively regulated by post-transcriptional and post-translational mechanisms, but the molecular basis remains unclear. In the present study, we examined the possibility that microRNA may be involved in the post-transcriptional regulation of human CYP2E1. In silico analysis identified a potential recognition element of miR-378 (MRE378) in the 3'-untranslated region (UTR) of human CYP2E1 mRNA. Luciferase assays using HEK293 cells revealed that the reporter activity of the plasmid containing the MRE378 was decreased by co-transfection of precursor miR-378, indicating that miR-378 functionally recognized the MRE378. We established two HEK293 cell lines stably expressing human CYP2E1 including or excluding 3'-UTR. When the precursor miR-378 was transfected into the cells expressing human CYP2E1 including 3'-UTR, the CYP2E1 protein level and chlorzoxazone 6-hydroxylase activity were significantly decreased, but were not in the cells expressing CYP2E1 excluding 3'-UTR. In both cell lines, the CYP2E1 mRNA levels were decreased by overexpression of miR-378, but miR-378 did not affect the stability of CYP2E1 mRNA. In a panel of 25 human livers, no positive correlation was observed between the CYP2E1 protein and CYP2E1 mRNA levels, supporting the post-transcriptional regulation. Interestingly, the miR-378 levels were inversely correlated with the CYP2E1 protein levels and the translational efficiency of CYP2E1. In conclusion, we found that human CYP2E1 expression is regulated by miR-378, mainly via translational repression. This study could provide new insight into the unsolved mechanism of the post-transcriptional regulation of CYP2E1.
authors: Drug Metabolism and Toxicology, Faculty of Pharmaceutical Sciences, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
authors: Takuya
authors: T
authors: Mohri
authors: Miki
authors: M
authors: Nakajima
authors: Tatsuki
authors: T
authors: Fukami
authors: Masataka
authors: M
authors: Takamiya
authors: Yasuhiro
authors: Y
authors: Aoki
authors: Tsuyoshi
authors: T
authors: Yokoi
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D002478:Cells, Cultured; D019392:Cytochrome P-450 CYP2E1 / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D008099:Liver / Q000201:enzymology; D008156:Luciferases / Q000378:metabolism; D035683:MicroRNAs / Q000502:physiology*
chemical_list: D020413:3' Untranslated Regions; C526012:MIRN378 microRNA, human; D035683:MicroRNAs; D008156:Luciferases; D019392:Cytochrome P-450 CYP2E1