SLC1A5-dependent glutamine uptake in hepatocytes promotes liver regeneration

The liver's remarkable regenerative capacity after injury restores essential functions for maintaining homeostasis. Understanding molecular circuits initiating liver regeneration leads to new therapies. Solute carrier family 1, member 5 (SLC1A5) is a key glutamine transporter crucial for hepatocyte proliferation. This study investigates the role of SLC1A5 in hepatocytes during liver regeneration and explores its underlying mechanisms.

We retrieved a hepatocyte-RNA sequencing dataset from mice post-PHx (GSE181761) and a single-nucleus-RNA sequencing dataset from human livers (GSE223561). THLE-2 human hepatocyte cell line was used to study SLC1A5 function in vitro, while magnetic nanoparticles carrying thyroxine-binding globulin (TBG)-promoter-driven Slc1a5 gRNA-Cas9 plasmids were administered to mice for hepatocyte-specific Slc1a5 deletion, enabling in vivo investigation.

We identified 58 significantly altered SLC family genes in hepatocytes post-PHx. A subset of 29 genes, selected based on q value, was linked to L-glutamine transmembrane transporter activity via Gene Ontology functional enrichment analysis, as well as glutamine secretion and L-glutamine import across the plasma membrane by Gene Ontology biological process enrichment analysis. Among these enriched genes, Slc1a5 emerged as the most critical gene regulating glutamine activity, with the highest expression observed in proliferating cyclin-positive hepatocytes. Slc1a5 upregulation on day 2 post-PHx was confirmed in vivo, with increased glutamine uptake and cyclin gene expression in proliferating hepatocytes during liver regeneration. Targeted delivery of Slc1a5-gRNA nanoparticles for hepatocyte-specific gene deletion significantly reduced glutamine uptake, hepatocyte proliferation, and impaired liver regeneration in both PHx and CCl4 injury models.

Together, SLC1A5 in hepatocytes facilitates glutamine uptake, upregulates cyclin gene expression, and promotes hepatocyte proliferation and liver regeneration.