Characterization of hepatic stellate cells (HSC) genes in the normal liver or diverse liver fibrotic models by scRNAseq and bulk RNAseq.. Characterization of hepatic stellate cells (HSC) genes in the normal liver or diverse liver fibrotic models by scRNAseq and bulk RNAseq.

Hepatocellular carcinoma (HCC), the fourth leading cause of cancer mortality, develops almost exclusively in patients with chronic liver disease (CLD) and advanced fibrosis. Here we interrogated functions of hepatic stellate cells (HSC), the main source of liver fibroblasts, during hepatocarcinogenPesis. Genetic depletion, activation or inhibition established HSC as tumour-promoting in mouse models of HCC. HSC were enriched in the preneoplastic environment, where they closely interacted with hepatocytes and modulated hepatocarcinogenesis by regulating hepatocyte proliferation and death. Analysis of mouse and human HSC subpopulations and their associated mediators by single cell RNA-sequencing in conjunction with genetic ablation revealed dual functions of HSC in hepatocarcinogenesis. Hepatocyte growth factor, enriched in quiescent and cytokine-producing HSC (cyHSC), protected from hepatocyte death and HCC development. In contrast, type I collagen, enriched in activated myofibroblastic HSC (myHSC), promoted proliferation and tumour development via increased stiffness and TAZ activation in pretumoural hepatocytes and via activation of discoidin domain receptor 1 in established tumours. An increasing HSC dysbalance between cyHSC and myHSC during liver disease progression was associated with elevated HCC risk in patients. In summary, the dynamic shift of HSC subpopulations and their mediators during CLD is associated with a switch from HCC protection to HCC promotion. Overall design: - Single Cell RNAseq of isolated HSC from fibrotic livers induced by CCl4 (RS039, n=1), TAZ+FPC-NASH diet (RS042, n=1) and HF-CDAA diet (RS043, n=1) - Bulk RNA sequencing of isolated HSC from FPC-treated mice (n=5), or by CCl4 (n=4) - Bulk RNA-sequencing from normal (n=8), adjacent (n=10) and HCC (n=10) mouse livers with or without HSC inhibition induced by YAP deletion in HSC during hepatocarcinogenesis induced by DEN+CCl4