title: Acid‑induced cell injury and death in lung epithelial cells is associated with the activation of mitogen‑activated protein kinases.
abstract: Gastric hydrochloric acid (HCl) has been regarded as a causative factor of acute lung injury (ALI). The activation of mitogen‑activated protein kinases (MAPKs) has been suggested to be a mechanism involved in the pathogenesis of ALI in vivo. However, the effects of HCl on MAPK activation in lung epithelial cells remain to be fully elucidated. Further investigation into the role of MAPK activation in acid‑induced cell injury and death is also needed. In the present study, BEAS‑2B cells were treated with HCl (pH 4.0 medium) for 5, 15 and 30 min, and the acidified medium was then removed. Cell viability and death were detected by MTT assay and trypan blue exclusion staining, respectively. The activation of MAPKs [c‑Jun N‑terminal kinase (JNK), p38 MAPK and extracellular signal‑regulated kinase (ERK) 1/2] was analyzed by western blot analysis. Cytotoxicity was assessed by lactate dehydrogenase (LDH) release, and IL‑8 levels in culture supernatants were measured by enzyme‑linked immunosorbent assay (ELISA). Cell apoptosis was detected as changes in the levels of capase‑3, Bad and fas by western blot analysis and the number of apoptotic cells by using Annexin V/propidium iodide (PI) staining. Following pre‑treatment with the JNK inhibitor II (10 µmol/l), the p38 inhibitor SB202190 (10 µmol/l) or the ERK inhibitor U0126 (10 µmol/l) for 30 min, BEAS‑2B cells were exposed to HCl for 30 min. Cell viability, cytotoxicity, IL‑8 levels and apoptosis were detected 4 h following acid stimulation. The viability of BEAS‑2B cells was inhibited and cell death was increased in the presence of HCl. HCl stimulation induced activation of MAPKs in a time‑dependent manner. HCl exposure increased the levels of IL‑8 and the release of LDH, and induced apoptosis in BEAS‑2B cells. JNK and p38 inhibitors increased cell viability and decreased cytotoxicity and cell apoptosis, while ERK inhibitor had no effect on cell viability, cytotoxicity or apoptosis. These results indicate that acid exposure induced epithelial cell injury and death. The activation of JNK and p38 is involved in HCl‑induced epithelial lung cell injury and death.
authors.affiliation: Department of Critical Care Medicine, Nanjing Zhong‑Da Hospital, Southeast University School of Medicine, Nanjing, Jiangsu 210009, P.R. China.
authors.forename: Qiuhua
authors.initials: Q
authors.lastname: Chen
authors.forename: Yingzi
authors.initials: Y
authors.lastname: Huang
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
authors.forename: Haibo
authors.initials: H
authors.lastname: Qiu
mesh_terms: D056809:Alveolar Epithelial Cells / Q000187:drug effects* / Q000378:metabolism* / Q000473:pathology; D017209:Apoptosis / Q000187:drug effects; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D005744:Gastric Acid; D006801:Humans; D006851:Hydrochloric Acid / Q000009:adverse effects*; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D013997:Time Factors
chemical_list: D047428:Protein Kinase Inhibitors; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D006851:Hydrochloric Acid