Study on the mechanism of P22077 to improve pulmonary fibrosis in mice by down-regulating β-catenin pathway

Hu Die; Zhao Dong; Huang Jizhen; Wu Lei

doi:10.3969/j.issn.1671-6450.2025.10.017

Abstract：Objective To observe the effects and potential mechanisms of the ubiquitin-specific protease 7(USP7)inhibitor P22077 on epithelial-mesenchymal transition(EMT)in alveolar epithelial cells and on pulmonary fibrosis in mice.Methods The experiment was conducted in the Central Laboratory of Renmin Hospital of Wuhan University from October 2023 to December 2024.Forty C57BL/6 mice were randomly divided into control group,model group,P22077-L group,and P22077-H group.A mouse pulmonary fibrosis model was established by intratracheal instillation of bleomycin(2 mg/kg).Dif-ferent doses of P22077 were administered intraperitoneally to mice in the P22077-L(10 mg·kg-1·d-1)and P22077-H(15 mg·kg-1·d-1)groups starting from day 7.On day 28,bronchoalveolar lavage fluid and lung tissue were collected.Path-ological changes in lung tissue were observed by HE staining and Masson staining.The expression of USP7,β-catenin,E-cadherin,and α-SMA in lung tissue was detected by Western blot.Immunohistochemical staining was used to detect the ex-pression of α-SMA and E-cadherin in mouse lung tissue.ELISA was used to measure the levels of inflammatory factors(TGF-β1,IL-1β,IL-6,TNF-α)in bronchoalveolar lavage fluid.For the cell experiment,groups included control group,model group,and P22077 group.Mouse alveolar epithelial cells(MLE12)were treated with TGF-β1(10 μg/L)to establish a cell model,and the P22077 group was treated with both TGF-β1 and P22077(10 μmol/L).After cell collection,the expression of USP7,β-catenin,E-cadherin,and α-SMA was detected by Western blot.Results Compared with the model group,HE and Masson staining showed that P22077 reduced lung tissue inflammation and fibrosis in a dose-dependent manner.Compared with the bleomycin(Blm)group,the protein expression of USP7,β-catenin,and α-SMA in lung tissue of the P22077-H group was significantly decreased,while E-cadherin expression was significantly increased,and inflammatory factor levels in bron-choalveolar lavage fluid were downregulated.In cell experiments,compared with the TGF-β1 group,the expression of USP7,β-catenin,and α-SMA in MLE12 cells of the P22077 group was significantly decreased,while E-cadherin expression was sig-nificantly increased.Conclusions P22077 can effectively inhibit EMT in alveolar epithelial cells and ameliorate pulmonary fibrosis in mice,and this effect is associated with downregulation of the β-catenin pathway.