Effects of bile acids and steroid/thyroid hormones on the expression of cholesterol 7 alpha-hydroxylase mRNA and the CYP7 gene in HepG2 cells.

Title

Effects of bile acids and steroid/thyroid hormones on the expression of cholesterol 7 alpha-hydroxylase mRNA and the CYP7 gene in HepG2 cells.

Creator

Crestani M; Karam W G; Chiang J Y

Publisher

Biochemical and biophysical research communications

Date

1994
1994-01

Description

The expression of cholesterol 7 alpha-hydroxylase mRNA levels in confluent HepG2 cultures was reduced by tauro- or glyco-conjugates of deoxycholate and chenodeoxycholate, but not by cholate. Ursodeoxycholates, on the other hand, stimulated the mRNA level. The 5'-upstream regions of rat cholesterol 7 alpha-hydroxylase gene (CYP7) were fused to luciferase reporter gene and the constructs, p-3616/Luc, p-224/Luc and p-160/Luc, were transiently transfected into HepG2 cells. Tauro-conjugates of deoxycholate and chenodeoxycholate inhibited the transcriptional activities of the gene constructs in the confluent cells, but not in subconfluent cells. These results reveal that bile acid responsive elements are located in the -160 fragment and also between nt -3616 and -224. Thyroid and steroid hormones stimulated transcriptional activity expressed in the confluent cells and their responsive elements are located upstream of nt -224. It appears that adult phenotypes are responsible for bile acid feedback and hormone response in HepG2 cells.

Subject

Animals; Bile Acids and Salts/*pharmacology; Cells; Cholesterol 7-alpha-Hydroxylase/*genetics; Cultured; Enzymologic/*drug effects; Gene Expression Regulation; Genetic; Genetic/genetics; Humans; Luciferases/biosynthesis/genetics; Messenger/*biosynthesis; Promoter Regions; Rats; Recombinant Fusion Proteins/biosynthesis; RNA; Steroids/*pharmacology; Thyroid Hormones/*pharmacology; Transcription; Transfection

Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Pages

546–553

Issue

2

Volume

198

Citation

Crestani M; Karam W G; Chiang J Y, “Effects of bile acids and steroid/thyroid hormones on the expression of cholesterol 7 alpha-hydroxylase mRNA and the CYP7 gene in HepG2 cells.,” NEOMED Bibliography Database, accessed May 18, 2021, https://neomed.omeka.net/items/show/3100.

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