Abstract Body: Introduction: Metabolic dysfunction associated steatotic liver disease (MASLD) affects approximately one third of the global population. The disease is initiated by lipid accumulation in hepatocytes and progresses to metabolic dysfunction associated steatohepatitis (MASH), characterized by increased lipotoxicity and inflammation. With continued progression, MASLD leads to irreversible liver injury, fibrosis, and ultimately cirrhosis. Notably, recent genome-wide association studies have identified a single-nucleotide polymorphism in the receptor tyrosine kinase EphA2, implicating it as a potential contributor to MASLD pathogenesis.
Hypothesis: Hepatic EphA2 promotes inflammation and alters hepatocyte metabolism to contribute to MASLD pathogenesis.
Methods: To investigate the role of EphA2 in MASLD progression, both global and hepatocyte specific EphA2 KO mice were fed a MASH inducing diet for 8, 16 or 24 weeks. To assess disease severity, molecular and histological analysis was conducted. Expression of EphA2, and its main ligand, ephrinA1, was assessed in human and mouse models of MASH. Additionally, primary hepatocytes were isolated from EphA2 KO mice and Huh7 cells treated with EphA2 siRNA. Changes in cell signaling were systematically assessed.
Results: Both global and hepatocyte specific EphA2 KO mice showed decreased inflammation and lipid accumulation following FPC diet feeding. RNA sequencing demonstrated enhanced expression of genes associated with fatty acid metabolism and beta-oxidation, and reduced expression of pro-inflammatory genes. We have also shown EphA2 deletion in primary hepatocytes and EphA2 Knockdown in Huh7 cells reduces lipid accumulation associated with enhanced mitochondrial biogenesis. While EphA2 expression is unaffected in mouse models of MASH and in human MASH, the ligand for the EphA2 receptor, ephrinA1, is reduced in both murine and human MASH. Consistent with these results, EphA2 is shown to be positively correlated with Hepatic Steatosis in human MASH, while ephrinA1 is negatively correlated.
Conclusion: Collectively, our data demonstrates altered EphA2 signaling increases inflammation and steatosis in MASLD.