RESUMEN
The aim of this study was to determine whether the anti-fibrotic effects of pirfenidone (Pirf) and nintedanib (Nint) associated with the regulation of the alveolar epithelial type 2 cell (AEC II)-mediated lung alveolar regeneration in single- and multiple-dosage animal models of bleomycin-induced pulmonary fibrosis. All procedures involving animal treatment were approved according to the Committee on the Ethics of Animal Experiments of the Institute of Materia Medica, Chinese Academy of Medical Sciences. We found that the Pirf and Nint treatment of mice decreased the lung weight index, inflammation level, and the content of hydroxyproline compared with nontreated fibrotic mice in the single dosage model. Also, Pirf and Nint increased the oxygen saturation level and improved the lung functions in fibrotic mice, indicating that both drugs have anti-fibrotic effects in this model. However, the anti-fibrotic effects of Pirf and Nint were not observed in the multiple-dosage model. Further studies showed that Pirf and Nint decreased the expression of β-catenin, Axin2, c-Myc, Cyclin D1, and inhibited the Wnt/β-catenin signaling pathway, suggesting that Pirf and Nint did not produce anti-fibrotic effects in the multiple-dosage model due to their inhibiting the Wnt/β-catenin pathway and suppressing the stemness of AEC II, namely, suppressing AEC II-mediated lung alveolar regeneration.
RESUMEN
TLR2 activity plays an important role in the pathogenesis of autoimmune diseases, tumor carcinogenesis and cardio-cerebrovascular diseases. To establish a TLR2 receptor-based cell screening model, NF-kappaB promoter-driven luciferase reporter plasmids were transfected into human embryonic kidney cells (HEK293) stably expressing human TLR2 and co-receptors CD14, TLR1 and TLR6. Single clones were then isolated and characterized. Using this screening system, a human TLR2-binding peptide C8 was obtained from the Ph.D.-7 Phage Display Peptide Library through biopanning and rapid analysis of selective interactive ligands (BRASIL). The binding characteristic of C8 with human TLR2 was evaluated by ELISA, flow cytometry and immunofluorescence. The NF-kappaB luciferase activity assay showed that C8 could activate the TLR2/TLR1 signaling pathway and induce the production of cytokines TNF-alpha and IL-6. In conclusion, the TLR2 receptor-based cell screening system is successfully established and a new TLR2-binding peptide is identified by using this system.