Heat Shock Protein 27 (Hsp27) Protects Lung Epithelial Cells from Hyperoxia‐Induced Cell Death

Abstract

Supplemental oxygen therapy (hyperoxia) is a common life‐saving practice for preterm babies with respiratory distress. Prolonged hyperoxia is one of the major contributing factors in cell death and the development of bronchopulmonary dysplasia (BPD), a chronic lung disease, in preterm babies. Hsp27 is the smallest inducible heat shock chaperone protein that modulates the ability of cells to respond to oxidative stress. Our DNA Superarray analysis revealed that hyperoxia significantly decreased Hsp27 gene expression in newborn rat lungs. Immunohistochemistry of Hsp27 confirmed that Hsp27 protein in epithelial cells of neonatal rat lungs was markedly decreased after hyperoxic exposure. In cultured human lung epithelial cells (A549), prolonged hyperoxia significantly reduced Hsp27 expression and caused cell death. Overexpression of hHsp27 could prevent hyperoxia‐induced cell death in cultured human lung epithelial cells. Our studies suggest that hyperoxia reduces Hsp27 expression in lung epithelial cells and overexpression of hHsp27 confers cytoprotection against hyperoxia‐induced cell death in lung epithelial cells.