title: Effects of oleic acid on SP-B expression and release in A549 cells.
abstract: OBJECTIVE
  Pulmonary surfactant-associated protein B (SP-B), which is synthesized and secreted by alveolar epithelial type II cells, is crucial for normal functioning of pulmonary surfactant. Degeneration of pulmonary surfactant is the essential cause of acute lung injury (ALI). ALI is often studied in animal models using oleic acid, and the effects of oleic acid on pulmonary surfactant and SP-B are not clear. In this study, we examined the effects of oleic acid on the A549 cell line which resembles the alveolar epithelial type II cells.
  
  
  METHODS
  A549 cells were exposed for 24 hours to 300, 400, 500 or 600 µM of oleic acid. Cell morphological changes were observed using an inverted microscope, and cell proliferation was quantified with the Cell Counting Kit-8. Extracellular SP-B levels were assessed by ELISA, whereas intracellular SP-B expression by Western blot.
  
  
  RESULTS
  Oleic acid caused dose-dependent changes in cell morphology of A549 cells and decreased their proliferation. This was accompanied by release of SP-B into extracellular supernatants and corresponding decrease of intracellular levels of this protein.
  
  
  CONCLUSIONS
  Oleic acid causes a dose-dependent injury to A549 cells, release of SP-B into extracellular compartment, and decrease of intracellular SP-B expression. Our findings provide mechanistic insights into animal modeling of ALI with oleic acid.
authors.affiliation: State Key Laboratory of Trauma, Burns and Combined Injury, Department 4, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, P. R. China. traumazjh@126.com.
authors.forename: D-J
authors.initials: DJ
authors.lastname: Zhou
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: X-J
authors.initials: XJ
authors.lastname: Zhang
authors.forename: C
authors.initials: C
authors.lastname: Ma
authors.forename: J
authors.initials: J
authors.lastname: Qiu
authors.forename: J-H
authors.initials: JH
authors.lastname: Zhou
mesh_terms: D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D019301:Oleic Acid / Q000494:pharmacology*; D037701:Pulmonary Surfactant-Associated Protein B / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D037701:Pulmonary Surfactant-Associated Protein B; D019301:Oleic Acid