Given the significant changes in DUSP22 expression in fatty liver, an in vitro model was then established using adenovirus-mediated shDUSP22 knockdown (Ad-shDUSP22) and adenovirus-mediated DUSP22 overexpression (Ad-DUSP22) vectors to initially investigate the regulatory effects of DUSP22 on hepatic steatosis in L02 cells cultured in CM-containing serum from NASH or No-steatosis individuals, and firstly DUSP22 deletion or overexpression had no significant influences on the expression alterations of other DUSPs (Supplementary Fig. 4a–g). This evidence concerns the gene DUSP22 and metabolic dysfunction-associated steatohepatitis.