EPHB2 promotes diet-induced MASH liver fibrosis

The EphB2 receptor tyrosine kinase is thought to participate in numerous fibroinflammatory disorders. In metabolic dysfunction-associated steatohepatitis (MASH), we find EphB2 becomes upregulated in activated hepatic stellate cells (HSCs) from humans with the disease and from mice fed liver-injuring high fat diets. Genetic deletion or point mutation that inactivates the EphB2 tyrosine kinase domain in mice mitigated diet-induced liver inflammation and fibrosis, whereas a catalytically overactive point mutant mouse developed exacerbated steatosis and hepatic damage. Silencing EPHB2 in primary human HSCs dampened the ability of TGFβ/SMAD signaling to activate the transdifferentiation of quiescent HSCs into profibrotic myofibroblasts, while HSC-specific deletion of the receptor, but not hepatocyte deletion, reduced liver scarring in multiple mouse models, even after fibrosis was established. Our studies demonstrate EphB2 forward signaling participates with TGFβ/SMAD signaling to bring about the pathogenesis of diet-induced fatty liver disease. Therapeutically targeting this receptor tyrosine kinase could counter MASH fibrosis.