Dual GIP/GLP-1 receptor agonist tirzepatide ameliorates hepatic steatosis and inflammatory responses in a MASLD mouse model associated with the CCL2/CCR2 axis.

BACKGROUND/OBJECTIVES: Metabolic dysfunction-associated steatotic liver disease (MASLD) is a common multisystem chronic progressive liver disease with a rising burden. Tirzepatide (TZP), a dual agonist of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors, has shown beneficial hepatic effects, but the related molecular mechanisms remain unclear. The aim of this study was to investigate the hepatic molecular signatures associated with TZP in MASLD. METHODS: A MASLD mouse model was established using a high-fat, high-fructose (HFHFr) diet. Male C57BL/8J mice (n = 32) were randomized to four groups: control (CON), HFHFr, HFHFr + semaglutide (Sema), and HFHFr + TZP. Hepatic transcriptomic and proteomic profiles were generated by RNA sequencing and liquid chromatography-mass spectrometry (LC-MS), respectively. Key molecular targets were validated by quantitative real-time PCR and immunoblotting of liver tissue. RESULTS: HFHFr feeding induced hyperglycaemia, increased HOMA-IR, elevated ALT/AST, and marked hepatic steatosis and inflammatory injury. Both Sema and TZP ameliorated these abnormalities. TZP was associated with lower hepatosomatic index, improved fasting glucose and HOMA-IR, and reduced hepatic MCP-1, IL-1β, TNF-α and GSDMD, with partial restoration of IL-10. Integrated liver transcriptomic-proteomic profiling highlighted chemokine signaling and PI3K-AKT pathway signatures to be associated with TZP. Further targeted validation showed that TZP treatment was associated with reduced hepatic CCL2/CCR2 axis components, and decreased PI3K abundance and lower AKT phosphorylation. CONCLUSION: TZP ameliorated hepatic steatosis and attenuated inflammatory responses in HFHFr-induced MASLD and was associated with downregulation of the CCL2/CCR2-linked chemokine signaling and PI3K-AKT-related inflammatory responses.