Abstract: Tissue injury and regenerative impairment drive hepatic failure and progressive liver pathologies. However, the spatial and molecular dynamics governing early-stage liver regeneration, particularly the balance between hepatocyte proliferation and metabolic adaptation, remain elusive. By integrating spatiotemporal sequencing of regenerating liver tissues with single-cell RNA sequencing of liver organoids mimicking regeneration initiation, we uncovered that spatial reorganization of splicing factors initiates preferential periportal hepatocyte reactivation. A reprogrammed hepatocyte subpopulation with elevated splicing factor activity exhibited regenerative hepatoprogenitor characteristics, prioritizing proliferative capacity over metabolic functionality. Mechanistically, pharmacological inhibition of RNA splicing upregulated ribosomal proteins, attenuating proliferative signaling. Functional screening identified spliceosomes (e.g., heterogeneous nuclear ribonucleoprotein U, HNRNPU) as critical regulators of hepatic zonation and regeneration. Hnrnpu knockout disrupted liver repair architecture and exacerbated metabolic dysfunction-associated steatotic liver disease (MASLD) phenotypes in both clinical cohorts and murine models. Our findings delineate a splicing factor-mediated spatial hierarchy controlling hepatocyte fate specification during regeneration, proposing a paradigm where spliceosomal activation licenses hepatoprogenitor transition. Crucially, chronic splicing factor deficiency provoked spontaneous hepatic steatosis, implicating spliceosomes as molecular hubs coupling regeneration with lipid metabolism. This work establishes a mechanistic framework for initiating hepatic repair and identifies spliceosomal targets such as HNRNPU for therapeutic interventions in chronic liver diseases, informing advanced treatment strategies including gene therapy and RNA-targeted modalities.
Funding Source: the National Natural Science Foundation of China (32122031 to Huili Hu and T2321004 to Huili Hu); the National Key R&D Program of China (2019YFA0111400 to Huili Hu)
