Single cell RNAseq at 48h and 72h in mice
Fifty percent of all acute liver failure (ALF) cases in the United States are due to acetaminophen (APAP) overdose. Assessment of canonical features of liver injury, such as plasma alanine aminotransferase activities are poor predictors of acute liver failure (ALF), suggesting the involvement of additional mechanisms independent of hepatocyte death. Previous work demonstrated a severe overdose of APAP results in impaired regeneration, the induction of senescence by p21, and increased mortality. We hypothesized that a discrete population of p21+ hepatocytes acquired a secretory phenotype that directly impedes liver recovery after a severe APAP overdose. Leveraging in-house human APAP explant liver and publicly available singlenuclei RNAseq data, we identified a subpopulation of p21+ hepatocytes enriched in a unique secretome of factors, such as Cxcl14. Spatial transcriptomics in the mouse model of APAP overdose confirmed the presence of a p21+ hepatocyte population that directly surrounded the necrotic areas. In both male and female mice, we found a dose-dependent induction of p21 and persistent circulating levels of the p21-specific constituent, Cxcl14, in the plasma after a severe APAP overdose. In parallel experiments, we targeted either the putative senescent hepatocytes with the senolytic drugs, dasatinib and quercetin, or Cxcl14 with a neutralizing antibody. We found that targeting Cxcl14 greatly enhanced liver recovery after APAP-induced liver injury, while targeting the senescent hepatocyte had no effect. This data supports that the sustained induction of p21 in hepatocytes with persistent Cxcl14 secretion are critical mechanistic events leading to ALF in mice and human patients. Overall design: C57BL/6J mice were treated with 300 mg/kg APAP or saline vehicle control. Then 48h or 72h later mice underwent a 2-step collagenase perfusion to isolate either a hepatocyte or non-parenchymal cell liver fraction via percoll gradient with differential centrifugation.