Foxa2-dependent hepatic gene regulatory networks depend on physiological state

Bochkis IM, Schug J, Rubins NE, Chopra AR, O'Malley BW, Kaestner KH. Foxa2-dependent hepatic gene regulatory networks depend on physiological state. Physiol Genomics 38: 186-195, 2009. First published May 5, 2009; doi: 10.1152/physiolgenomics.90376.2008.-Bile acids are powerful detergents produced by the liver to aid in the absorption of dietary lipids. We recently reported a novel role for Foxa2 in bile acid metabolism. The winged helix transcription factor Foxa2 is required to prevent intrahepatic cholestasis and liver injury in mice fed a cholic acid-enriched diet. Here, we use functional genomics to study how Foxa2 regulates its targets in a cholic acid-dependent manner. We found that multiple signaling pathways essential for the hepatic response to acute liver injury are impaired in livers of Foxa2-deficient mice, suggesting that the deletion of Foxa2 in the hepatocyte affects the liver on a large scale. We also discovered distinct feed-forward regulatory loops controlling Foxa2-dependent targets in a cholic acid-dependent or -independent manner. We show that Foxa2 interacts with different transcription factors to achieve gene expression responses appropriate for each physiologic state.