Resident CD24 +LCN2 + LPCs aggravate fibrosis and inflammatory progression via the recruitment of TPPP3 +COL10A1 + macrophages in NASH.

Resident CD24 ⁺LCN2 ⁺ liver progenitor cells (LPCs) reportedly contribute to the expanding ductular reaction and macrophage-mediated inflammation associated with chronic liver damage. Both ductular reactions and macrophage-driven inflammation are associated with liver fibrosis and injury in various mouse liver disorders. This study aims to investigate the molecular phenotypes of LPCs and their regulatory mechanisms in humans with non-alcoholic steatohepatitis (NASH). Single-cell RNA sequencing (scRNA-seq) datasets are used to characterize the status and molecular phenotypes of LPCs in clinical NASH samples. To elucidate the regulatory mechanisms of LPCs, CellChat and NicheNet are employed to assess cell-cell communication between LPCs and other cell types. The findings are validated using RNA sequencing datasets associated with NASH progression, NASH mouse models (CDAHFD and HFD), and human NASH liver samples. Results show that resident CD24 ⁺LCN2 ⁺ LPCs are identified and found to be significantly enriched in NASH patients. Cell communication analyses predict strong interactions between LPCs and proinflammatory macrophage subtypes. Additionally, in NASH, the liver recruits peripheral blood mononuclear cell (PBMC)-derived macrophages and polarizes them into proinflammatory subtypes. The macrophage subtype MP-2 is identified as the primary recipient of LPC-derived signals, exhibiting marked hyperactivation of the NF-κB pathway and a strong association with liver fibrosis. Finally, the MP-2 markers COL10A1 and TPPP3 are characterized and validated. In summary, this study reveals that resident CD24 ⁺LCN2 ⁺ LPCs are activated in NASH and contribute to fibrosis progression by promoting the activation of the proinflammatory COL10A1 ⁺TPPP3 ⁺ macrophage subtype.