Systematic screening identifies USP20 as an accelerator of metabolic dysfunction-associated steatotic liver disease via driving de novo lipogenesis

Background and aims: Excessive hepatic lipid production drives disrupted lipid homeostasis. Although deubiquitinases have emerged as key modulators of metabolic enzymes, their involvement in de novo lipogenesis (DNL) remains elusive. Results: Hepatic USP20 is identified by the multi-screening system based on biological assays of the constructed 105 DUB-plasmids library, combined with transcript analysis of multi-species with MASLD. USP20 activates the DNL pathway through multi-omics integrated analysis and isotope-metabolic flux tracing. The most potential USP20-interacting protein, FASN is screened by IP-MS. USP20 interacts with FASN and deubiquitinates K48-linked FASN to block proteasome-mediated degradation. Consequently, downstream lipogenic genes are activated in DNL pathway and excessive PA occurs in hepatocytes. Through rank by virtual screening, based on the pocket alignment of USP20 and molecular dynamics simulation, the small molecule compound-C2 screened markedly inhibits USP20, thereby suppressing DNL to alleviate MASLD. Conclusions: Our finding establishes USP20 as a central driver of DNL via deubiquitinating FASN. A promising therapeutic strategy targeting-USP20 is provided for MASLD.