The novel inhibitor PRI-724 for Wnt/ß-catenin/CBP signaling ameliorates bleomycin-induced pulmonary fibrosis in mice.

Purpose/Aim of the Study: Wnt/ß-catenin signaling was reported to be activated in pulmonary fibrosis, and was focused on as a target for antifibrotic therapy. However, the mechanism how the inhibition of Wnt/ß-catenin signaling ameliorate pulmonary fibrosis has not been fully elucidated. The purpose of this study is to explore the target cells of Wnt/ß-catenin inhibition in pulmonary fibrosis and to examine the antifibrotic effect of the novel inhibitor PRI-724 specifically disrupting the interaction of ß-catenin and CBP. Materials and Methods: The effect of C-82, an active metabolite of PRI-724, on the expression of TGF-ß1 and α-smooth muscle actin (SMA) was examined on fibroblasts and macrophages. We also examined the effects of PRI-724 in mouse model of bleomycin-induced pulmonary fibrosis. Results: The activation and increased accumulation of ß-catenin in the canonical pathway were detected in lung fibroblasts as well as macrophages stimulated by Wnt3a using Western blotting. Treatment with C-82 reduced CBP protein and increased p300 protein binding to ß-catenin in the nucleus of lung fibroblasts. In addition, C-82 inhibited the expression of SMA in lung fibroblasts treated with TGF-ß, indicating the inhibition of myofibroblast differentiation. In the fibrotic lungs induced by bleomycin, ß-catenin was stained strongly in macrophages, but the staining of ß-catenin in alveolar epithelial cells and fibroblasts was weak. The administration of PRI-724 ameliorated pulmonary fibrosis induced by bleomycin in mice when administered with a late, but not an early, treatment schedule. Analysis of bronchoalveolar fluid (BALF) showed a decreased number of alveolar macrophages. In addition, the level of TGF-ß1 in BALF was decreased in mice treated with PRI-724. C-82 also inhibited the production of TGF-ß1 by alveolar macrophages. Conclusions: These results suggest that the ß-catenin/CBP inhibitor PRI-724 is a potent antifibrotic agent that acts by modulating the activity of macrophages in the lungs.

Virtual screening leads to the discovery of an effective antagonist of lymphocyte function-associated antigen-1.

The binding of lymphocyte function-associated antigen-1 (LFA-1) to its ligand on endothelial cells, intercellular adhesion molecule-1 (ICAM-1), is a crucial step in the migration of leukocytes during the early stages of inflammation and is also involved in T-cell activation. In this paper, we report the identification of a series of novel antagonists of the LFA-1/ICAM-1 interaction using ligand-based virtual screening (VS), analogue design, and structure-activity relationship (SAR) analysis. Candidate compounds were evaluated in protein binding and cell adhesion assays. Experimental evaluation of only 25 candidates selected from a pool of approximately 2.5 million database compounds identified an initial hit that could be expanded and converted into a lead that effectively blocked the interaction between LFA-1 and ICAM-1.