Continuous Activation of C/EBPβ Transcription Factor Prevents Fibrosis Resolution After Alcohol Cessation

Abstinence is an important therapeutic intervention for patients with alcohol-associated liver disease (ALD). However, fibrosis improvement after cessation is not uniform and some patients do not improve.

Mice were fed high-fat diet with 20% alcohol in the drinking water for 20 weeks (ALD) followed by 4 weeks of chow diet with plain water (resolution). scATAC-seq dataset was analyzed using Signac R package. Cebpb floxed mice received AAV-TBG-Cre or AAV-control at the time of alcohol cessation. Hepatocyte-macrophage and endothelial cell-hepatocytes crosstalk was investigated using a Transwell coculture system. To test the role of angiopoietin mice were treated with recombinant angiopoietin-1, 1 week after alcohol cessation.

We analyzed differentially accessible regions in hepatocytes from control, ALD, or 4 weeks post alcohol cessation mice and identified transcription factors activated in ALD that remained activated after alcohol withdrawal. The top hit was CCAAT enhancer binding protein beta (C/EBPβ). We found that hepatocyte-specific Cebpb knockout at the time of alcohol cessation promoted fibrosis resolution. The resolution was mediated by altered hepatocyte-macrophage crosstalk. C/EBPβ suppressed the expression of CYP3A family of enzymes in hepatocytes and downstream macrophage collagen degradation ability. Cebpb knockout in hepatocytes promoted a proresolving phenotype in liver macrophages. We further identified upstream events leading to persistent C/EBPβ activation. C/EBPβ was induced by alcohol-mediated endothelial changes during ALD development and resolution. Restoring endothelial cell function with angiopoietin-1 supplementation reduced C/EBPβ and promoted fibrosis resolution.

Taken together, alcohol-induced C/EBPβ activation is a key driver of poor disease resolution in ALD and a promising target for patients who fail to recover after alcohol abstinence.