The cell cycle inhibitor p21 promote mouse lung fibrosis by activating alveolar macrophages / 药学学报

This study was to determine the expression of the cell cycle inhibitor p21 in alveolar macrophages (AMs) and the role of p21 in activation of AMs in bleomycin (BLM) injury-induced lung fibrosis. The expression of CD206 in AMs was measured by immunofluorescence staining. Reverse transcription-polymerase chain reaction (RT-PCR) assay was used to detect the expression of macrophage activation markers. The coculture assay for macrophage and fibroblast was employed to explore the effect of macrophage on fibroblast activation. Immunofluorescence staining and western blotting assay were adopted to detect the expression of p21 in fibrotic tissues. AMs were treated with p21 knockdown or overexpression virus, RT-PCR and the co-culture system were used to explore the effect of p21 expression on macrophage activation. The Experimental Animal Welfare Ethics Committee of the Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College approved all of the protocols for this research. Our results showed that the expression of CD206 and macrophage activation markers was increased in AMs from fibrotic mice, indicating that AMs from fibrotic mice were associated with a profibrotic phenotype. Moreover, the expression of p21 was upregulated in AMs after BLM treatment. Depletion of p21 suppressed macrophage activation, while overexpression of p21 promoted the profibrotic phenotype of AMs from healthy mice. In summary, BLM injury causes the progressive accumulation of p21 in AMs, which induces the production of a number of profibrotic factors promoting the development of pulmonary fibrosis.

Pirfenidone and nintedanib inhibit the lung alveolar regeneration in chronic pulmonary fibrosis mouse / 药学学报

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.