B1344 ameliorates non-alcoholic steatohepatitis in HFCD-HF/G-induced mice: exploring the therapeutic efficacy and mechanism of a novel FGF21 analogue.

The endocrine cytokine, fibroblast growth factor 21 (FGF21), shows therapeutic potential for non-alcoholic steatohepatitis (NASH) but has pharmacokinetic limitations. B1344 is a modified PEGylated FGF21 analogue with enhanced stability and bioactivity. Researches are required to further explore its effect and possible mechanisms against NASH. C57BL/6J mice were induced by 10-week high-fat/calorie diet with high fructose/glucose water (HFCD-HF/G). B1344 was then administered for 8 weeks. Systemic metabolic parameters, hepatic injury, insulin resistance, adipose tissue (AT) function, and FGF21 resistance were evaluated. RNA-sequencing of liver and adipose tissues was carried out. B1344 attenuated HFCD-HF/G-induced metabolic disorder and hepatic damages. Liver transcriptomics revealed its multi-target modulation of lipid metabolism, inflammation, fibrosis, etc. Systemic insulin resistance and downsream signaling in liver, muscle and AT was improved by B1344. Notably, it restored AT dysfunction and alleviated FGF21 resistance. AT RNA-sequencing further identified its regulation in inflammation, angiogenesis, hypoxia and senescence. Collectively, B1344 demonstrates robust efficacy against NASH in HFCD-HF/G-induced mice. The multi-target modulation in liver and AT including FGF21 resistance was involved in its underlying mechanisms. This study not only provides support for further clinical trials of B1344, but also benefits deeper understanding of FGF21 function.