Abstract
ABSTRACT
Background and Aims
Liver sinusoidal endothelial cells (LSECs) are liver‐resident antigen‐presenting cells that induce immune tolerance, a feature exploited by persistent viruses. Toll‐like receptor (TLR) ligands can override this tolerance, but whether metabolic reprogramming underlies LSEC activation remains unknown. We investigated whether TLR ligand‐induced functional changes in LSECs require glycolysis and explored the underlying mechanisms.
Methods
LSECs from wild‐type and chronic hepatitis B virus (HBV) replication mice were stimulated with TLR2 ligand P3C or TLR9 ligand ODN1826. LSEC maturation, cytokine production and T cell‐priming capacity were assessed. Glycolytic flux was measured by metabolomics and Seahorse analysis. The glycolysis inhibitor 2‐deoxy‐D‐glucose (2‐DG) was used, and mTORC1 pathway involvement was examined.
Results
The TLR2 ligand P3C promoted LSEC maturation, while the TLR9 ligand ODN1826 enhanced IL‐12 production. Both ligands potentiated LSEC‐induced T cell responses. In LSECs isolated from a mouse model of chronic HBV replication, P3C and ODN1826 also induced maturation and enhanced T cell‐activating capacity, albeit to a weaker extent. Metabolomics and Seahorse analyses revealed that TLR2/9 ligands enhanced glycolysis and oxidative phosphorylation in LSECs, accompanied by activation of the mTORC1/HIF‐1α/c‐Myc axis. Blocking glycolysis with 2‐DG significantly reduced co‐stimulatory molecule expression on P3C‐stimulated LSECs and IL‐12 production by ODN1826‐stimulated LSECs in both wild‐type and chronic HBV models. Mechanistically, 2‐DG suppressed the mTORC1 pathway, thereby attenuating TLR ligand‐induced responses.
Conclusions
TLR ligand‐induced activation and pro‐inflammatory functions of LSECs critically depend on glycolysis via the mTORC1 signalling pathway. This reveals a key metabolic mechanism underlying LSEC immune regulation during innate stimulation.