Extracellular acidification-induced CXCL8 production through a proton-sensing receptor OGR1 in human airway smooth muscle cells: a response inhibited by dexamethasone

Journal of Inflammation

Hidenori Yamada¹  Haruka Aoki-Saito¹  Takeshi Hisada¹  Yosuke Kamide¹  Fumikazu Okajima²  Koichi Sato³  Yuko Waseda⁴  Masaki Anzai⁴  Yukihiro Umeda⁴  Tamotsu Ishizuka⁴  Maiko Kadowaki⁴  Hiroko Shigemi⁴  Miwa Morikawa⁴ 

[1] Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine;Laboratory of Signal Transduction, Faculty of Pharmaceutical Sciences, Aomori University;Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University;Third Department of Internal Medicine, Faculty of Medical Sciences, University of Fukui;

关键词: OGR1;    Airway smooth muscle cell;    Proton;    CXCL8;    NF-κB;    Dexamethasone;   

DOI  :  10.1186/s12950-019-0207-1

来源: DOAJ

【 摘 要 】

Abstract Background Human airway smooth muscle cells (ASMCs) contribute to bronchial contraction and airway hyperresponsiveness in patients with bronchial asthma. They also generate cytokines, chemokines, and matricellular proteins. Ovarian cancer G protein-coupled receptor 1 (OGR1) senses extracellular protons and mediates the production of interleukin-6 (IL-6) and connective tissue growth factor (CTGF) in ASMCs. Methods ASMCs were stimulated for the indicated time by pH 6.3 or pH 7.4-adjusted Dulbecco’s Modified Eagle Medium (DMEM) containing 0.1% bovine serum albumin (BSA) (0.1% BSA-DMEM). As a control stimulant, pH 7.4-adjusted 0.1% BSA-DMEM containing 10 ng/mL tumor necrosis factor-α (TNF-α) was used. Interleukin-8/C-X-C motif chemokine ligand 8 (CXCL8) mRNA expression in ASMCs was quantified by RT-PCR using real-time TaqMan technology. CXCL8 secreted from ASMCs was measured by enzyme-linked immunosorbent assay (ELISA). Phosphorylation at serine 536 of NF-κB p65 and binding of p65 to oligonucleotide containing an NF-κB consensus binding site were analyzed by Western blotting and an ELISA-based kit. Results Acidic pH induced a significant increase of CXCL8 mRNA expression and CXCL8 protein secretion in ASMCs. ASMCs transfected with small interfering RNA (siRNA) targeted for OGR1 produced less CXCL8 compared with those transfected with non-targeting siRNA. Protein kinase C (PKC) inhibitor, MEK1/2 inhibitor, and the inhibitor of IκB phosphorylation reduced acidic pH-stimulated CXCL8 production in ASMCs. Dexamethasone also inhibited acidic pH-stimulated CXCL8 production of ASMCs in a dose-dependent manner. Dexamethasone did not affect either phosphorylation or binding to the consensus DNA site of NF-κB p65. Conclusions CXCL8 released from ASMCs by extracellular acidification may play a pivotal role in airway accumulation of neutrophils. Glucocorticoids inhibit acidic pH-stimulated CXCL8 production independent of serine 536 phosphorylation and the binding to DNA of NF-κB p65, although NF-κB activity is essential for CXCL8 production in ASMCs.

【 授权许可】

Unknown