GPNMB+Gal-3+ Hepatic Parenchymal Cells Promote Immunosuppressive Microenvironment Formation and Hepatocellular Carcinogenesis.
Hepatocellular carcinoma (HCC) involves a multistep pathological process in which heterogenous cells are evolved to shape an immunosuppressive microenvironment. Yet it remains largely unknown regarding the specific cell populations and their evolving routes essential for HCC development. Here, we created a rat model mimicking human HCC and generated a single-cell resolution atlas to HCC development. Specifically, we identified three populations of hepatic parenchymal cells during HCC progression, i.e., metabolic hepatocyte (HC Meta ), hepatic progenitor cell-like population with differentiation potential (HPC-like Diff ) and immunosuppressive malignant transformation subset (H-M Immu ). These three distinct subpopulations formed an oncogenic trajectory depicting a dynamic landscape of hepatocyte carcinogenesis, with signature genes reflecting the transition from HPC-like Diff to H-M Immu . Cross-species comparative analysis further revealed the H-M Immu subset to be highly conserved. Importantly, the H-M Immu (GPNMB + Gal-3 + ) cells exhibit both malignant and immunosuppressive properties. Moreover, SOX18 was found to be required for the generation of GPNMB + Gal-3 + H-M Immu cells and for their ability to form tumors. Enrichment of GPNMB + Gal-3 + H-M Immu subset was found to be associated with poor prognosis and higher rate of recurrence for HCC patients. Collectively, we unraveled the single-cell evolving mechanism of HCC and uncovered GPNMB + Gal-3 + H-M Immu cells as a major subset contributing to the immunosuppressive microenvironment and HCC malignance Overall design: Rats treated with DEN up to 16 weeks