An extended transcription factor regulatory network controls hepatocyte identity

Abstract

AbstractCell identity is specified by a core transcriptional regulatory circuitry (CoRC), typically limited to a small set of interconnected cell‐specific transcription factors (TFs). By mining global hepatic TF regulons, we reveal a more complex organization of the transcriptional regulatory network controlling hepatocyte identity. We show that tight functional interconnections controlling hepatocyte identity extend to non‐cell‐specific TFs beyond the CoRC, which we call hepatocyte identity (Hep‐ID)CONNECT TFs. Besides controlling identity effector genes, Hep‐IDCONNECT TFs also engage in reciprocal transcriptional regulation with TFs of the CoRC. In homeostatic basal conditions, this translates into Hep‐IDCONNECT TFs being involved in fine tuning CoRC TF expression including their rhythmic expression patterns. Moreover, a role for Hep‐IDCONNECT TFs in the control of hepatocyte identity is revealed in dedifferentiated hepatocytes where Hep‐IDCONNECT TFs are able to reset CoRC TF expression. This is observed upon activation of NR1H3 or THRB in hepatocarcinoma or in hepatocytes subjected to inflammation‐induced loss of identity. Our study establishes that hepatocyte identity is controlled by an extended array of TFs beyond the CoRC.