NUP85 Mediates Endoplasmic Reticulum Stress through the USP47/ASK1 Signaling Pathway to Regulate the Progression of Liver Fibrosis

ABSTRACT Liver fibrosis is a pathological process caused by excessive deposition of extracellular matrix (ECM) in the liver stimulated by chronic injury or inflammation. Nuclear pore protein 85 (NUP85) has been implicated in the development of various liver diseases. However, its involvement in liver fibrosis remains unclear. The present study aimed to explore the role of NUP85 in liver fibrosis. The expression level of NUP85 was found to be elevated in the liver tissues of liver fibrosis patients and mice. Knockdown of NUP85 not only ameliorated liver injury and collagen deposition, but also suppressed endoplasmic reticulum stress (ERS). Conversely, the opposite pathological and biochemical changes are observed with NUP85 overexpression. Mechanistically, NUP85 competitively binds ubiquitin‐specific peptidase 47 (USP47) to apoptosis signal‐regulating kinase 1 (ASK1), deubiquitinates lysine residue 805 of ASK1, and regulates the activation of ASK1, thereby exacerbating collagen deposition and ERS. Furthermore, we developed a CREKA‐coupled liposome as a targeted delivery system to deliver Mogroside V (MV), a pharmacological inhibitor of NUP85, to activated HSCs and attenuate liver fibrosis. Taken together, the present study demonstrated that NUP85 is a novel regulator of liver fibrosis and that the NUP85‐USP47‐ASK1 signaling pathway might be a strategy for therapeutic intervention.