Association between endoplasmic reticulum stress pathway mediated by inositolrequiring kinase 1 and AECⅡ apoptosis in preterm rats induced by hyperoxia
JU Hui-Min, LU Hong-Yan, ZHANG Yan-Yu, WANG Qiu-Xia, ZHANG Qiang
Department of Pediatrics, Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu 212001, China
Abstract：Objective To study the association between endoplasmic reticulum stress (ERS) pathway mediated by inositol-requiring kinase 1 (IRE1) and the apoptosis of type Ⅱ alveolar epithelial cells (AECⅡs) exposed to hyperoxia. Methods The primarily cultured AECⅡs from preterm rats were devided into an air group and a hyperoxia group. The model of hyperoxia-induced cell injury was established. The cells were harvested at 24, 48, and 72 hours after hyperoxia exposure. An inverted phase-contrast microscope was used to observe morphological changes of the cells. Annexin V/PI double staining flow cytometry was performed to measure cell apoptosis. RT-PCR and Western blot were used to measure the mRNA and protein expression of glucose-regulated protein 78 (GRP78), IRE1, X-box binding protein-1 (XBP-1), and C/EBP homologous protein (CHOP). An immunofluorescence assay was performed to measure the expression of CHOP. Results Over the time of hyperoxia exposure, the hyperoxia group showed irregular spreading and vacuolization of AECⅡs. Compared with the air group, the hyperoxia group showed a significantly increased apoptosis rate of AECⅡs and significantly increased mRNA and protein expression of GRP78, IRE1, XBP1, and CHOP compared at all time points (P < 0.05). The hyperoxia group had significantly greater fluorescence intensity of CHOP than the air group at all time points. In the hyperoxia group, the protein expression of CHOP was positively correlated with the apoptosis rate of AECⅡs and the protein expression of IRE1 and XBP1 (r = 0.97, 0.85, and 0.88 respectively; P < 0.05). Conclusions Hyperoxia induces apoptosis of AECⅡs possibly through activating the IRE1-XBP1-CHOP pathway.
JU Hui-Min,LU Hong-Yan,ZHANG Yan-Yu et al. Association between endoplasmic reticulum stress pathway mediated by inositolrequiring kinase 1 and AECⅡ apoptosis in preterm rats induced by hyperoxia[J]. CJCP, 2016, 18(9): 867-873.
Balany J, Bhandari V. Understanding the impact of infection, inflammation, and their persistence in the pathogenesis of bronchopulmonary dysplasia[J]. Front Med (Lausanne), 2015, 2:90.
[2]
Jin L, Yang H, Fu J, et al. Association between oxidative DNA damage and the expression of 8-oxoguanine DNA glycosylase 1 in lung epithelial cells of neonatal rats exposed to hyperoxia[J]. Mol Med Rep, 2015, 11(6):4079-4086.
[3]
Kim SR, Lee YC. Endoplasmic reticulum stress and the related signaling networks in severe asthma[J]. Allergy Asthma Immunol Res, 2015, 7(2):106-117.
[4]
Koyama M, Furuhashi M, Ishimura S, et al. Reduction of endoplasmic reticulum stress by 4-phenylbutyric acid prevents the development of hypoxia-induced pulmonary arterial hypertension[J]. Am J Physiol Heart Circ Physiol, 2014, 306(9):H1314-H1323.
[5]
Lu HY, Zhang J, Wang QX, et al. Activation of the endoplasmic reticulum stress pathway involving CHOP in the lungs of rats with hyperoxia-induced bronchopulmonary dysplasia[J]. Mol Med Rep, 2015, 12(3):4494-4500.
[6]
Wang LL, Hu RC, Dai AG, et al. Bevacizumab induces A549 cell apoptosis through the mechanism of endoplasmic reticulum stress in vitro[J]. Int J Clin Exp Pathol, 2015, 8(5):5291-5299.
Hou A, Fu J, Yang H, et al. Hyperoxia stimulates the transdifferentiation of type Ⅱ alveolar epithelial cells in newborn rats[J]. Am J Physiol Lung Cell Mol Physiol, 2015, 308(9):L861-L872.
[9]
Feng J, Chen X, Sun X, et al. Expression of endoplasmic reticulum stress markers GRP78 and CHOP induced by oxidative stress in blue light-mediated damage of A2Econtaining retinal pigment epithelium cells[J]. Ophthalmic Res, 2014, 52(4):224-233.
[10]
Oyadomari S, Mori M. Roles of CHOP/GADD153 in endoplasmic reticulum stress[J]. Cell Death Differ, 2004, 11(4):381-389.
[11]
Liu SH, Wu CT, Huang KH, et al. C/EBP homologous protein (CHOP) deficiency ameliorates renal fibrosis in unilateral ureteral obstructive kidney disease[J]. Oncotarget, 2016, 7(16):21900-21912.
[12]
Choo-Wing R, Syed MA, Harijith A, et al. Hyperoxia and interferon-γ-induced injury in developing lungs occur via cyclooxygenase-2 and the endoplasmic reticulum stressdependent pathway[J]. Am J Respir Cell Mol Biol, 2013, 48(6):749-757.
[13]
Hetz C, Martinon F, Rodriguez D, et al. The unfolded protein response:integrating stress signals through the stress sensor IRE1α[J]. Physiol Rev, 2011, 91(4):1219-1243.
[14]
van Schadewijk A, van't Wout EF, Stolk J, et al. A quantitative method for detection of spliced X-box binding protein-1(XBP1) mRNA as a measure of endoplasmic reticulum (ER) stress[J]. Cell Stress Chaperones, 2012, 17(2):275-279.
[15]
Ghosh R, Wang L, Wang ES, et al. Allosteric inhibition of the IRE1α RNase preserves cell viability and function during endoplasmic reticulum stress[J]. Cell, 2014, 158(3):534-548.
