Epithelial disruption of Gab1 perturbs surfactant homeostasis and predisposes mice to lung injuries

In this study, in vitro knockdown of Gab1 was shown to decrease the surfactant proteins (SPs) levels in AT-IIs. We further examined in vivo Gab1 functions through alveolar epithelium-specific Gab1 knockout mice (Gab1/). In vivo Gab1 deficiency leads to a decrease in SP synthesis and the appearance of disorganized lamellar bodies. Histological analysis of the lung sections in Gab1/ mice shows no apparent pathological alterations or inflammation. However, Gab1/ mice demonstrate inflammatory responses during the LPS-induced acute lung injury. Similarly, in mice challenged with bleomycin, fibrotic lesions were found to be aggravated in Gab1/. These observations suggest that the abolishment of Gab1 in AT-IIs impairs SP homeostasis, predisposing mice to lung injuries. In addition, we observed that the production of surfactants in AT-IIs overexpressing Gab1 mutants, in which Shp2 phosphatase and PI3K kinase binding sites have been mutated (Gab1Shp2, Gab1PI3K), has been considerably attenuated. Together, these findings provide the direct evidence about the roles of docking protein Gab1 in lungs, adding to our understanding of acute and interstitial lung diseases caused by the disruption of alveolar SP homeostasis.

Source: AJP: Lung Cellular and Molecular Physiology - December 11, 2016 Category: Respiratory Medicine Authors: Wang, K., Qin, S., Liang, Z., Zhang, Y., Xu, Y., Chen, A., Guo, X., Cheng, H., Zhang, X., Ke, Y. Tags: CALL FOR PAPERS Source Type: research