title: Stimulated bronchial epithelial cells release bioactive lysophosphatidylcholine 16:0, 18:0, and 18:1.
abstract: OBJECTIVE
  In human subjects and animal models with acute and chronic lung injury, the bioactive lysophosphatidylcholine (LPC) is elevated in lung lining fluids. The increased LPC can promote an inflammatory microenvironment resulting in lung injury. Furthermore, pathological lung conditions are associated with upregulated phospholipase A2 (PLA2), the predominant enzyme producing LPC in tissues by hydrolysis of phosphatidylcholine. However, the lung cell populations responsible for increases of LPC have yet to be systematically characterized. The goal was to investigate the LPC generation by bronchial epithelial cells in response to pathological mediators and determine the major LPC species produced.
  
  
  METHODS
  Primary human bronchial epithelial cells (NHBE) were challenged by vascular endothelial growth factor (VEGF) for 1 or 6 h, and condition medium and cells collected for quantification of predominant LPC species by high performance liquid chromatography-tandem mass spectrometry (LC-MS-MS). The cells were analyzed by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) for PLA2. The direct effects of LPC in inducing inflammatory activities on NHBE were assessed by transepithelial resistance as well as expression of interleukin-8 (IL-8) and matrix metalloproteinase-1 (MMP-1).
  
  
  RESULTS
  VEGF stimulation of NHBE for 1 or 6 h, significantly increased concentrations of LPC16:0, LPC18:0, and LPC18:1 in condition medium compared to control. The sPLA2-selective inhibitor (oleyloxyethyl phosphorylcholine) inhibited the VEGF-induced release of LPC16:0 and LPC18:1 and PLA2 activity. In contrast, NHBE stimulated with TNF did not induce LPC release. VEGF did not increase mRNA of PLA2 subtypes sPLA2-X, sPLA2-XIIa, cPLA2-IVa, and iPLA2-VI. Exogenous LPC treatment increased expression of IL-8 and MMP-1, and reduced the transepithelial resistance in NHBE.
  
  
  CONCLUSIONS
  Our findings indicate that VEGF-stimulated bronchial epithelial cells are a key source of extracellular LPCs, which can function as an autocrine mediator with potential to induce airway epithelial inflammatory injury.
authors.affiliation: Department of Pharmacology, Rush University Medical Center, Chicago, IL, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhuge
authors.affiliation: Department of Medicinal Chemistry & Pharmacognosy, University of Illinois, Chicago, IL, USA.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yuan
authors.affiliation: Department of Medicinal Chemistry & Pharmacognosy, University of Illinois, Chicago, IL, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: van Breemen
authors.affiliation: Department of Pharmacology, Rush University Medical Center, Chicago, IL, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Degrand
authors.affiliation: Department of Pharmacology, Rush University Medical Center, Chicago, IL, USA.
authors.forename: Oksana
authors.initials: O
authors.lastname: Holian
authors.affiliation: Department of Medicine, Rush University Medical Center, Chicago, IL, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Yoder
authors.affiliation: Department of Pharmacology, Rush University Medical Center, Chicago, IL, USA.
authors.forename: Hazel
authors.initials: H
authors.lastname: Lum
keywords: Bronchial epithelium; lysophosphatidylcholine; phospholipase A2