A Mouse Model for Metabolic Dysfunction-associated Steatotic Liver Disease and Hepatocellular Carcinoma [ATAC-seq]
The lack of an appropriate preclinical model of non-alcoholic fatty liver disease (NAFLD) that recapitulates the whole disease spectrum impedes exploration of disease pathophysiology and the development of effective treatment strategies. Therefore, we developed new mose model with Streptozotocin (STZ)and high-fat diet (HFD). In breif, male C57BL/6J mice were injected with low-dose streptozotocin (40 mg/kg) for 5 consecutive days beginning at 7 weeks of age and subsequently fed a high-fat diet from week 8 (STZ+HFD) onwards. Hepatic histopathology, transcriptomics, epigenetics, and metabolic phenotypes were evaluated at various time-points. The hepatic transcriptomes of STZ+HFD mice and NAFLD patients with similar liver histopathology were compared. In STZ+HFD mice, dietary changes from HFD to standard chow and administration of tirzepatide, a dual glucose-dependent insulinotropic polypeptide/glucagon-like peptide-1 receptor agonist, were introduced to assess the therapeutic efficacy of these interventions. STZ+HFD mice gradually developed fatty liver, non-alcoholic steatohepatitis (NASH), hepatic fibrosis, and hepatocellular carcinoma (HCC) in the context of metabolic dysfunction. In particular, from 32 weeks of age, NASH and advanced fibrosis were evident. At 38 weeks, a proportion of STZ+HFD mice developed HCC, which was subsequently observed in all mice up to 68 weeks of age. Furthermore, the hepatic transcriptomic features of STZ+HFD mice closely reflected those of patients with NASH and NAFLD-related HCC. Notably, dietary changes and tirzepatide administration alleviated NASH, hepatic fibrosis, and hepatic tumorigenesis in STZ+HFD mice. Put together, we established a murine model recapitulating the main histopathologic, transcriptomic, and metabolic alterations observed in NAFLD patients with metabolic dysfunction was successfully established. Overall design: We performed  ATAC-seq profiling in the four groups of C57BL/6J mice clasffied by STZ treatment and dietary method (STZ+HFD, STZ+standard chow diet(SCD), HFD only, SCD only) at 20 weeks of age to examine how STZ+HFD mice rapidly progress to NASH.