Macrophages trigger injury-induced hepatocyte reprogramming via IL-6/gp130/STAT3 axis [ChIP-Seq]

The liver is a pivotal organ possessing remarkable regenerative capacity. By employing murine liver injury models and lineage tracing strategy, recent studies have demonstrated that differentiated hepatocytes undergo reprogramming to SOX9+HNF4α+ liver progenitor-like cells (LPLCs), and serve as a totally new cell source for mammalian liver regeneration. However, it is largely unknown how hepatocyte reprogramming is regulated. In this study, we focus on analyzing the microenvironment cues in triggering hepatocyte reprogramming in liver injuries. By performing single-cell RNA sequencing (scRNA-seq) of hepatocyte reprogramming in liver injury, we find immune response is significantly activated. Notably, by lineage depletion, macrophages, especially kupffer cells, but not T cells, B cells, natural killer cells or neutrophils, are found essential for hepatocyte reprogramming and liver regeneration. IL-6, derived specifically from activated kupffer cells, triggers hepatocyte reprogramming via gp130/STAT3 signaling. Furthermore, STAT3 triggers gene expression by binding to Arid1a-dependent pre-opened regeneration-responsive enhancers (RREs) of reprogramming genes. Collectively, this study provides key insights into kupffer cells/IL-6/STAT3-mediated hepatocyte reprogramming and liver regeneration, which may serve as the base for new therapeutic strategies in facilitating endogenous repair mechanisms. Hepatocytes were perfused and isolated from normal diet feeding and DDC diet feeding Sox9-CreERT2; Rosa-LSL-tdTomato (LPLC tracing tools) mice livers, analysis of genomic occupancy of H3K27ac in hepatocytes by ChIP-seq. Hepatoblasts were FACS from E12.5 fetal liver via DLK1 expression and were analyzed in genomic occupancy of H3K27ac. For high-quality pSTAT3 ChIP-seq, hepatocyte were perfused and isolated from normal diet liver with HTVi of IL6 plasmids (5ug/mL) for 3 days.