Objective: To investigate the changes of Wnt7b/β-catenin signaling pathway molecules in the differentiation of fetal rat alveolar epithelial type II cells (fAEC2).
Methods: Fetal rat lung tissues were extracted from pregnant SD rats (19 days), and then fAEC2 were isolated and purified. After fAEC2 were cultured for 48, 72, 96 hours, the morphological changes of fAEC2 and the expression of β-catenin were respectively observed by inverted microscope and immunofluorescence. The mRNA expressions of Wnt7b, cyclin D1, pulmonary surfactant C (SP-C) and aquaporin 5 (AQP5) were detected by real-time quantitative PCR. The protein expressions of cyclin D1, nucleus β-catenin, SP-C and AQP5 were measured by Western blotting.
Results: β-catenin was expressed in cell membrane when fAEC2 were cultured for 48 hours; the expression of β-catenin decreased in cell membrane while enhanced in cytoplasm and nucleus at 72 hours; whole-cell β-catenin expression was lowered at 96 hours. The expressions of Wnt7b and cyclin D1 mRNAs were significantly raised at 72 hours and reduced obviously at 96 hours compared with 48 hours. SP-C mRNA expression level went down gradually with the extended culture time, and AQP5 mRNA level went up gradually. The protein expressions of cyclin D1 and nucleus β-catenin were significantly enhanced at 72 hours and weakened at 96 hours compared with 48 hours. SP-C protein expression was down-regulated with the prolonged culture time, and AQP5 protein expression was up-regulated.
Conclusion: Wnt7b/β-catenin signaling pathway may play an important role in fAEC2 transdifferentiation.