SRA

The lack of an appropriate preclinical model of metabolic dysfunction-associated steatotic liver disease (MASLD) that recapitulates the whole disease spectrum impedes exploration of disease pathophysiology and the development of effective treatment strategies. Considering the fact that MASLD patients accompanying type 2 diabetes mellitus (T2DM) have high risk of developing metabolic dysfunction-associated steatohepatitis (MASH), advanced fibrosis, and HCC, we treated low-dose streptozotocin (STZ; 40 mg/kg) for 5 consecutive days and subsequently fed a high-fat diet (HFD) to male C57BL/6J mice at 7 weeks of age (STZ+HFD). STZ+HFD mice gradually developed fatty liver, MASH, hepatic fibrosis, and hepatocellular carcinoma (HCC) in the context of metabolic dysfunction. In particular, from 20 weeks of age, MASH was evident, and from 32 weeks of age, advanced fibrosis was developed. 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 obese patients with T2DM, MASH and MASLD-related HCC. Notably, dietary changes and tirzepatide administration alleviated MASH, hepatic fibrosis, and hepatic tumorigenesis in STZ+HFD mice. In conclusion, a murine model recapitulating the main histopathologic, transcriptomic, and metabolic alterations observed in MASLD patients with metabolic dysfunction was successfully established. Overall design: To investigate transcriptomic alterations during MASLD progression, we profiled hepatic transcriptome of the model mouse at different ages with RNA-seq (7 weeks, healthy control; 8 weeks, acute STZ-treated state; 14-20 weeks, MASL to MASH transition; 32 weeks, MASH with fibrosis; 44 weeks, MASH with advanced fibrosis; 50-56 weeks, MASLD-related dysplastic nodules and HCC. Then we compared hepatic transcriptome of mice with that of human NAFLD patients with different MASLD acitivty score and fibrosis stage using RNA-seq profiling. We also performed RNA-seq profiling in hepatic tumors developed in model mice at 44-56 weeks. In addition, we performed RNA-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 and 32 weeks of age to examine how STZ+HFD mice rapidly progress to NASH. And we performed RNA-seq profiling in the model mice with dietary change to chow for 6 or 18 weeks with control unchanged group, and the model mice treated with tirzepatide or vehicle for 10 to 11 weeks at different ages (21-32 weeks, 28-38 weeks, and 41-52 weeks).