HNF4α contributes to hepatic CAR dysfunction in polymicrobial sepsis

Constitutive androstane receptor (CAR) is a xenobiotic nuclear receptor mainly expressed in the liver, where it regulates drug metabolism and energy homeostasis. CAR has emerged as a promising therapeutic target for diabetes, fatty liver disease, and alcoholic liver disease, but it has not been investigated in the context of sepsis. Here, we show that sepsis impairs CAR function in the liver, partly due to reduced transcription mediated by HNF4α, the key liver identity transcription factor, and partly due to decreased DNA binding, caused by chromatin remodeling, also mediated by HNF4α. This impairment leads to the downregulation of several genes and proteins involved in monocarboxylic acid, fatty acid, and xenobiotic metabolism, contributing to increased sepsis lethality, and is associated with an elevated hepatic acute phase response. LC-MSMS analysis was used to identify the proteins differentially expressed in the liver 24h after sepsis onset.