Cysteinyl-leukotrienes induce vascular endothelial growth factor production in human monocytes and bronchial smooth muscle cells.

Abstract

BACKGROUND:

Cysteinyl leukotrienes (cysLTs) are suggested to be implicated in the process of airway remodelling in asthma.

OBJECTIVE:

We investigated the potential for cysLTs to modulate vascular endothelial growth factor (VEGF) expression, a growth factor involved in the angiogenesis of airway remodelling.

METHODS:

VEGF mRNA and protein were quantified by real-time PCR and ELISA, respectively. VEGF promoter activation was assessed using luciferase gene-tagged promoter constructs.

RESULTS:

We found that LTD(4) induction of VEGF in human monocytes and bronchial smooth muscle cells is cysLT1 dependent. Stimulation of HEK293 cells stably expressing cysLT1 or cysLT2 with cysLTs showed a concentration-dependent activation of the VEGF promoter and a time-dependent increase in VEGF mRNA and protein. For the cysLT1-mediated response, mutations of hypoxia-induced factor-1 (HIF-1) sites failed to reduce cysLT-induced VEGF promoter activation and 5' deletions showed that the proximal region containing one AP-1 and four specificity protein 1 (Sp1) sites was necessary. Pretreatment with inhibitors of c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK), but not p38, and an overexpression of dominant negative forms of c-Jun, c-Fos or Ras suggested the implication of mitogen-activated protein kinases and AP-1. Mutation of the AP-1-binding element failed to prevent VEGF transactivation suggesting that AP-1 might not act directly on the promoter. Moreover, inhibition of Sp1-dependent transcription by mithramycin completely inhibited VEGF promoter transactivation and VEGF mRNA expression by LTD(4) . Finally, mutations of Sp1 binding elements prevented VEGF promoter transactivation.

CONCLUSION AND CLINICAL RELEVANCE:

Our data indicate for the first time that cysLTs can transcriptionally activate VEGF production via cysLT1 receptors, with the involvement of JNK, ERK, the AP-1 complex and Sp1. These findings suggest that cysLTs may be important in the angiogenic process of airway remodelling and potentially provide a previously unknown benefit of using cysLT1 receptor antagonists in the prevention or treatment of airway remodelling in asthma.

• Authors: S Poulin, C Thompson, M Thivierge, S Véronneau, S McMahon, C M Dubois, J Stankova, M Rola-Pleszczynski
• Journal: Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology (Clin Exp Allergy) Vol. 41 Issue 2 Pg. 204-17 (Feb 2011) ISSN: 1365-2222 [Electronic] England
• PMID: 21121979 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2010 Blackwell Publishing Ltd.

Chemical References

• Leukotrienes
• RNA, Messenger
• Receptors, Leukotriene
• Vascular Endothelial Growth Factor A
• Cysteine

Topics

• Bronchi (cytology)
• Cysteine (analysis)
• HEK293 Cells
• Humans
• Leukotrienes (chemistry, pharmacology)
• Monocytes (drug effects, metabolism)
• Muscle, Smooth (cytology, drug effects, metabolism)
• RNA, Messenger (biosynthesis, genetics)
• Receptors, Leukotriene (metabolism)
• Vascular Endothelial Growth Factor A (biosynthesis, genetics, immunology)