Calcitonin Gene-Related Peptide Enhances the Expression of Signaling Molecules of the Wnt 7b/Beta-Catenin Pathway in Rat Type II Alveolar Epithelial Cells Under Hyperoxia
Background: Hyperoxic lung injury is characterized by epithelial cell death and leukocyte infiltration/inflammation in the lung. Calcitonin gene-related peptide (CGRP) has been shown to improve survival of lung epithelial cells and reduce hyperoxic lung injury in rats. However, the mechanism of CGRP protective activity is not completely understood. The Wnt7b/β-catenin pathway plays an important role in lung development, repair and regeneration. This study therefore was designed to examine the regulatory role of CGRP in the Wnt7b/β-catenin pathway in type II alveolar epithelial cell (AEC II) under hyperoxia.
Methods: Rat neonates and AEC II from premature rats were exposed to hyperoxia in the absence or presence of CGRP, Wnt7b and β-catenin protein levels were measured by Western blot analysis, while T cell factor (TCF) and c-myc mRNA levels were determined by reverse transcription-polymerase chain reaction (RT-PCR).
Results: In the rat lung, both Wnt7b and β-catenin proteins were detectable, and hyperoxia significantly increased Wnt7b and β-catenin protein expression. AEC II, after exposure to hyperoxia, had significantly higher levels of Wnt7b and β-catenin proteins, and TCF and c-myc mRNAs, which was further enhanced by CGRP.
Conclusions: CGRP stimulates the expression of multiple molecules in the Wnt 7b/β-catenin pathway in AEC II under hyperoxia, which might be part of the mechanism by which CGRP protects the lung from hyperoxia-induced injury.
Cell Mol Med Res. 2017;1(1):15-19