title: RANTES expression induced by Toll-like receptor 4 ligand in rat airway smooth muscle cells.
abstract: Airway smooth muscle cells (ASMCs) have been reported to express Toll-like receptors (TLRs) and take part in the pathogenesis of asthma exacerbation. Though TLRs were found to activate epidermal growth factor receptor (EGFR) in airway epithelial cells, little is known about the association of TLR ligands with EGFR signaling pathways in ASMCs. Using primary cultured ASMCs from Brown Norway rats, TLR4, eotaxin, and RANTES mRNA were examined by real-time quantitative RT-PCR after stimulation with the TLR4 ligand, lipopolysaccharides (LPS). The concentration of RANTES protein in culture supernatant was measured by ELISA. The effect of EGFR signaling inhibitors on RANTES expression was examined as well. Phosphorylation of EGFR after stimulation was examined by Western Blotting. Rat ASMCs expressed TLR4 and eotaxin, and LPS upregulated RANTES production. The EGFR tyrosine kinase inhibitor AG1478, the phosphoinositide 3-kinase (PI3K) inhibitor LY294002, and the matrix metalloproteinase (MMP) inhibitor GM6001 inhibited RANTES expression induced by LPS. LPS phosphorylated EGFR. TLR4 activation can induce RANTES expression via EGFR transactivation and PI3K/Akt pathway in rat ASMCs. MMP-induced EGFR proligand cleavage and ligand binding to EGFR seem to be involved in this pathway. These findings may be critical in the pathogenesis of asthma exacerbation by airway infection.
authors.affiliation: Department of Integrated Pulmonology, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Okayasu
authors.forename: Meiyo
authors.initials: M
authors.lastname: Tamaoka
authors.forename: Satoshi
authors.initials: S
authors.lastname: Takayama
authors.forename: Yasunari
authors.initials: Y
authors.lastname: Miyazaki
authors.forename: Yuki
authors.initials: Y
authors.lastname: Sumi
authors.forename: Naohiko
authors.initials: N
authors.lastname: Inase
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Yoshizawa
mesh_terms: D000818:Animals; D001249:Asthma / Q000503:physiopathology; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D054413:Chemokine CCL11 / Q000187:drug effects*; D018946:Chemokine CCL5 / Q000037:antagonists & inhibitors / Q000187:drug effects*; D002867:Chromones / Q000494:pharmacology; D004151:Dipeptides / Q000494:pharmacology; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000187:drug effects; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D061965:Matrix Metalloproteinase Inhibitors / Q000494:pharmacology; D009025:Morpholines / Q000494:pharmacology; D032389:Myocytes, Smooth Muscle / Q000187:drug effects*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors; D011799:Quinazolines / Q000494:pharmacology; D011914:Rats, Inbred BN; D015398:Signal Transduction / Q000187:drug effects; D051197:Toll-Like Receptor 4 / Q000187:drug effects*; D014132:Trachea / Q000166:cytology / Q000187:drug effects*; D015533:Transcriptional Activation / Q000187:drug effects; D020032:Tyrphostins / Q000494:pharmacology
chemical_list: D054413:Chemokine CCL11; D018946:Chemokine CCL5; D002867:Chromones; D004151:Dipeptides; D008070:Lipopolysaccharides; D061965:Matrix Metalloproteinase Inhibitors; D009025:Morpholines; C078131:N-(2(R)-2-(hydroxamidocarbonylmethyl)-4-methylpentanoyl)-L-tryptophan methylamide; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011799:Quinazolines; C495347:Tlr4 protein, rat; D051197:Toll-Like Receptor 4; D020032:Tyrphostins; C101044:RTKI cpd; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D066246:ErbB Receptors; D017027:Protein Tyrosine Phosphatases