A Combination of Transcriptomics and Metabolomics Uncovers Enhanced Bile Acid Biosynthesis in HepG2 Cells Expressing CCAAT/Enhancer-Binding Protein β (C/EBPβ), Hepatocyte Nuclear Factor 4α (HNF4α), and Constitutive Androstane Receptor (CAR)
journal contributionposted on 19.02.2016, 07:04 by Marina Blazquez, Aitor Carretero, James K. Ellis, Toby J. Athersuch, Rachel Cavill, Timothy M. D. Ebbels, Hector C. Keun, José V. Castell, Agustín Lahoz, Roque Bort
The development of hepatoma-based in vitro models to study hepatocyte physiology is an invaluable tool for both industry and academia. Here, we develop an in vitro model based on the HepG2 cell line that produces chenodeoxycholic acid, the main bile acid in humans, in amounts comparable to human hepatocytes. A combination of adenoviral transfections for CCAAT/enhancer-binding protein β (C/EBPβ), hepatocyte nuclear factor 4α (HNF4α), and constitutive androstane receptor (CAR) decreased intracellular glutamate, succinate, leucine, and valine levels in HepG2 cells, suggestive of a switch to catabolism to increase lipogenic acetyl CoA and increased anaplerosis to replenish the tricarboxylic acid cycle. Transcripts of key genes involved in bile acid synthesis were significantly induced by approximately 160-fold. Consistently, chenodeoxycholic acid production rate was increased by more than 20-fold. Comparison between mRNA and bile acid levels suggest that 12-alpha hydroxylation of 7-alpha-hydroxy-4-cholesten-3-one is the limiting step in cholic acid synthesis in HepG2 cells. These data reveal that introduction of three hepatocyte-related transcription factors enhance anabolic reactions in HepG2 cells and provide a suitable model to study bile acid biosynthesis under pathophysiological conditions.
Read the peer-reviewed publication
adenoviral transfectionschenodeoxycholic acidincrease lipogenic acetyl CoAcholic acid synthesisCCAATconstitutive androstane receptorpathophysiological conditionstricarboxylic acid cycleanabolic reactionsstudy hepatocyte physiologyConstitutive Androstane ReceptorHNFHepG 2 CellsMetabolomics Uncovers Enhanced BileHepG 2 cellsvaline levelsbile acidHepG 2 cell linechenodeoxycholic acid production ratebile acid synthesisstudy bile acid biosynthesisbile acid levelsintracellular glutamatemodelfactor 4α