Category: Technical References, EpiAirway
267. TUMOR NECROSIS FACTOR ALPHA (TNFα) INDUCTION OF THYMUS AND ACTIVATION REGULATED CHEMOKINE (TARC) EXPRESSION IS MEDIATED BY 15-LIPOXYGENASE 15-(LOX)-2 IN THE EPIAIRWAY™ HUMAN TRACHEAL/BRONCHIAL EPITHELIAL MODEL.
Jackson1, G.R., Last1, T.J., Klausner1, M., Kubilus1, J., Shappell2, S.B., Brash2, A.R. and Hayden1, P. 1MatTek Corporation, Ashland, MA USA, and 2Department of Pathology, Vanderbilt University School of Medicine, Nashville, TN USA. Presented at the American Thoracic Society Meeting, Atlanta, GA, May (2002).
RATIONALE: T-Helper 2-type (TH2) T cells play a predominant role in human airway inflammation and asthma. TARC, a specific chemoattractant for TH2 cells, is induced by TNFα treatment of human airway cells, however, the cellular pathways involved in mediating TARC induction by TNFα are not fully understood.
METHODS: Researchers at the Vanderbilt University School of Medicine and MatTek Corp. used the EpiAirway™ in vitro human tracheal/bronchial epithelial model to study expression of TARC, 15-LOX-1 and 15-LOX-2 following treatment with TNFα, interferon-γ (INFγ), interleukin-4 (IL-4), IL-13 or various combinations of these cytokines. Western blotting, ELISA and RT-PCR were utilized to analyze protein and mRNA expression.
RESULTS: Treatment of EpiAirway tissues with TNFα or IL-13 significantly induced TARC protein secretion by EpiAirway. The LOX inhibitor nordihydroguairetic acid blocked TNFα or IL-13 induced TARC secretion. INFγ also caused a slight induction of TARC protein secretion. RT-PCR revealed that constitutive expression of 15-LOX-1 was enhanced by IL-4 and IL-13. Additionally, TNFα was found to induce expression of 15-LOX-2 message and protein, while INFγ inhibited the TNFα-induced increase in both message and protein.
CONCLUSIONS: Induction of TARC by TNFα and IL-13 is mediated by 15-LOX-2 and possibly 15-LOX-1, but the effect of INFγ appears to be mediated by an alternate pathway. These results provide a link between TNFα, 15-LOX-2 and TARC and may help to explain how TNFα functions to promote human airway inflammation in allergy and asthma.
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Applications: Asthma, Cytokine expression/analysis, Inflammation - airway
Keywords: 15-LOX-1, 15-LOX-2, 15-Lipoxygenase, Airway, Asthma, Bronchial, Chemoattractant, Cytokines, ELISA, EpiAirway, Gene expression, IL-13, IL-4, INF-gamma, Inflammation, Interferon gamma, Interleukin 4, LOX, Messenger RNA (mRNA), NHBE, Nordihydroguairetic acid, Normal human tracheal/bronchial epithelial model, RT-PCR, T-Helper 2-type T cells, TARC, TH2, TNF-a, Tracheal, Tumor necrosis factor alpha, Western blotting