Synthesized HMGB1 peptide prevents the progression of inflammation, steatosis, fibrosis, and tumor occurrence in a non‐alcoholic steatohepatitis mouse model.

Aim: Non‐alcoholic steatohepatitis (NASH) with fibrosis eventually leads to cirrhosis and hepatocellular carcinoma. Thus, the development of therapies other than dietary restriction and exercise, particularly those that suppress steatosis and fibrosis of the liver and have a long‐term beneficial effect, is necessary. We aimed to evaluate the therapeutic effects of the HMGB1 peptide synthesized from box A using the melanocortin‐4 receptor‐deficient (Mc4r‐KO) NASH model mouse. Methods: We performed short‐ and long‐term administration of this peptide and evaluated the effects on steatosis, fibrosis, and carcinogenesis using Mc4r‐KO mice. We also analyzed the direct effect of this peptide on macrophages and hepatic stellate cells in vitro and performed lipidomics and metabolomics techniques to evaluate the effect. Results: Although this peptide did not show direct effects on macrophages and hepatic stellate cells in vitro, in the short‐term administration model, we could confirm the reduction of liver damage, steatosis, and fibrosis progression. The results of lipidomics and metabolomics suggested that the peptide might ameliorate NASH by promoting lipolysis via the activation of fatty acid β‐oxidation and improving insulin resistance. In the long‐term administration model, this peptide prevented progression to cirrhosis but retained the steatosis state, that is, the peptide prevents the progression to "burnt‐out NASH." This peptide inhibited carcinogenesis by about one‐third. Conclusion: This HMGB1 peptide can reduce liver damage, improve fibrosis and steatosis, and inhibit carcinogenesis, suggesting that the peptide would be a new treatment candidate for NASH and can contribute to the long‐term prognosis for patients with NASH. [ABSTRACT FROM AUTHOR]