Ghrelin protects against lipopolysaccharide-induced acute respiratory distress syndrome through the PI3K/AKT pathway |
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Authors: | Lishan Zhang Shanhui Ge Wanmei He Qingui Chen Caixia Xu Mian Zeng |
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Institution: | 1.Department of Medical Intensive Care Unit, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China;2.Institute of Pulmonary Diseases, Sun Yat-Sen University, Guangzhou, Guangdong, China;3.Research Center of Translational Medicine, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China |
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Abstract: | Pulmonary endothelial barrier dysfunction is a major pathophysiology observed in acute respiratory distress syndrome (ARDS). Ghrelin, a key regulator of metabolism, has been shown to play protective roles in the respiratory system. However, its effects on lipopolysaccharide (LPS)-induced pulmonary endothelial barrier injury are unknown. In this study, the effects of ghrelin on LPS-induced ARDS and endothelial cell injury were evaluated in vivo and in vitro. In vivo, mice treated with LPS (3 mg/kg intranasal application) were used to establish the ARDS model. Annexin V/propidium iodide apoptosis assay, scratch-wound assay, tube formation assay, transwell permeability assay, and Western blotting experiment were performed to reveal in vitro effects and underlying mechanisms of ghrelin on endothelial barrier function. Our results showed that ghrelin had protective effects on LPS-induced ARDS and endothelial barrier disruption by inhibiting apoptosis, promoting cell migration and tube formation, and activating the PI3K/AKT signaling pathway. Furthermore, ghrelin stabilized LPS-induced endothelial barrier function by decreasing endothelial permeability and increasing the expression of the intercellular junction protein vascular endothelial cadherin. LY294002, a specific inhibitor of the PI3K pathway, reversed the protective effects of ghrelin on the endothelial cell barrier. In conclusion, our findings indicated that ghrelin protected against LPS-induced ARDS by impairing the pulmonary endothelial barrier partly through activating the PI3K/AKT pathway. Thus, ghrelin may be a valuable therapeutic strategy for the prevention or treatment of ARDS. |
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Keywords: | ghrelin acute respiratory distress syndrome PI3K endothelial cells |
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