Expression of functional leukotriene B4 receptors on human airway smooth muscle cells

• Published in: Journal of allergy and clinical immunology Vol. 124; no. 1; pp. 59 - 65.e3
• Main Authors: Watanabe, Satoko, BS, Yamasaki, Akira, MD, PhD, Hashimoto, Kiyoshi, MD, PhD, Shigeoka, Yasushi, MD, PhD, Chikumi, Hiroki, MD, PhD, Hasegawa, Yasuyuki, MD, PhD, Sumikawa, Takashi, MD, PhD, Takata, Miyako, PhD, Okazaki, Ryota, MD, Watanabe, Masanari, MD, PhD, Yokogawa, Tsuyoshi, BS, Yamamura, Miki, MD, Hayabuchi, Tatsuya, MD, Gerthoffer, William T., PhD, Halayko, Andrew J., PhD, Shimizu, Eiji, MD, PhD
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier 01.07.2009; Elsevier Limited
• Subjects: Allergy and Immunology; Biological and medical sciences; Blotting, Western; Bronchi - immunology; Bronchi - metabolism; Cell cycle; Cell Line; Cell Movement; Cell Proliferation; Chronic obstructive pulmonary disease, asthma; Cyclin-Dependent Kinases - metabolism; Dehydrogenases; Epidermal growth factor; Flow cytometry; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Gene Expression Regulation; Humans; Immunohistochemistry; Immunopathology; Kinases; Medical sciences; Mitogen-Activated Protein Kinase 3 - metabolism; Muscular system; Myocytes, Smooth Muscle - immunology; Myocytes, Smooth Muscle - metabolism; Phosphorylation; Pneumology; Polyclonal antibodies; Proteins; Receptors, Leukotriene B4 - genetics; Receptors, Leukotriene B4 - metabolism; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - metabolism; Sarcoidosis. Granulomatous diseases of unproved etiology. Connective tissue diseases. Elastic tissue diseases. Vasculitis; Signal Transduction; Smooth muscle; Cysteinyl leukotriene; JNK; hTERT-ASM; Human airway smooth muscle cell immortalized by stable ectopic expression of human telomerase reverse transcriptase; BLT; AHR; Airway smooth muscle; DMEM; Leukotriene B 4; Epidermal growth factor; G-protein coupled receptor; LTB 4; ASM; Dulbecco's modified Eagle medium; c-Jun N-terminal kinase; EGF; airway remodeling; airway smooth muscle cells; Mitogen-activated protein kinase; MAPK; Leukotriene B 4 receptor; cysLT; Asthma; Airway hyperresponsiveness; MEK; GPCR; Mitogen-activated protein kinase kinase; Human; Lung disease; Immunopathology; Respiratory disease; Leukotriene receptor; Arachidonic acid derivatives; Smooth muscle; Remodeling; Respiratory system; Myocyte; Respiratory tract; Immunology; Leukotriene B4; Eicosanoid; Bronchus disease; Obstructive pulmonary disease; LTB
• ISSN: 0091-6749; 1097-6825
• DOI: 10.1016/j.jaci.2009.03.024

Background Leukotriene B4 (LTB4 ) increases in induced sputum and exhaled breath condensate in people with asthma. Furthermore, the TH 2-type immune response and airway hyperresponsiveness induced by ovalbumin sensitization is markedly suppressed in LTB4 receptor (BLT) 1 null mice. These studies suggest that LTB4 may contribute to asthma pathophysiology. However, the direct effects of LTB4 on human airway smooth muscle (ASM) have not been studied. Objectives We sought to determine the expression of LTB4 receptors on human ASM and its functional role in mediating responses of human ASM cells, and the effect of LTB4 on these cells. Methods Immunohistochemistry, RT-PCR, Western blotting, and flow cytometry were used to determine the expression of LTB4 receptors. To determine the effect of LTB4 on human ASM cells, cell proliferation was assessed by counting cells, and chemokinesis was assessed by gold particle phagokinesis assay. Results We confirmed expression of both BLT1 and BLT2 in human ASM cells in bronchial tissue and in cell culture. LTB4 markedly induced cyclin D1 expression, proliferation, and chemokinesis of human ASM cells. LTB4 also induced phosphorylation of both p42/p44 mitogen-activated protein kinase (MAPK) and downstream PI3 kinase effector, Akt1. However, we observed no induction of c-Jun N-terminal kinase or p38 MAPK. Notably, LTB4 -induced migration and proliferation of ASM cells were inhibited by the BLT1 specific antagonist, U75302, and by inhibitors of p42/p44 MAPK phosphorylation (U1026), and PI3 kinase (LY294002). Conclusions These observations are the first to suggest a role for a LTB4 -BLT1 signaling axis in ASM responses that may contribute to the pathogenesis of airway remodeling in asthma.