Cellular communication networks in fibrosis: Insights from the MASLD pig model.

BACKGROUND: This research aims to reveal the cellular cross talk in fibrosis liver using transgenic pigs (TG) expressing humanized risk genes (PNPLA3I148M-GIPRdn-hIAPP) as a metabolic dysfunction-associated steatotic liver disease (MASLD) model. METHODS AND RESULTS: The study uses single-nucleus sequencing to reveal the differentiation and interaction characteristics of various cell populations in the liver during the development of MASLD. After 6 months of high-fat, high-sucrose diet induction, the model pigs exhibited obvious liver pathological features, including fat deposition, inflammatory cell aggregation, fibrosis, and blocked insulin signaling pathways, similar to PNPLA3 rs738409 C>G carriers. Single-nucleus RNA sequencing showed that pigs share a high correlation with human hepatic cell types and zonation. HSCs in TG pigs are more activated, showing enhancing fibrosis-related pathways and declining retinol metabolism. Pseudo-trajectory analysis revealed that over 90% of macrophages in TG liver differentiated to Fate 1 (CD68hi) with higher expression of major histocompatibility complex-II molecules, proinflammatory cytokines, phagosomes, and lysosomal-related genes. Active cell interactions were found between HSCs, endothelial cells, and Fate1 macrophages. Ligand and receptor interactions, including FGF23-FGFR, PDGFs-PDGFRs, EFNA1-EPHRs, and CXCL12-CXCR4/CXCR7, were predicted to involve in hepatic fibrosis in model pigs. CONCLUSIONS: The transgenic pig model of MASLD exhibits liver pathological features consistent with patients with MASLD. Our data supplemented the mechanism by which PNPLA3 mutations lead to hepatic steatosis, depicted a detailed atlas of hepatic profibrosis cellular network, and provided a reliable large animal model and data reference for MASLD drug development and precision treatment.