Narumoto_2013_Biochem.Biophys.Res.Commun_438_175

Acetylcholine (ACh) exerts various anti-inflammatory effects through alpha7 nicotinic ACh receptors (nAChRs). We have previously shown that secreted lymphocyte antigen-6/urokinase-type plasminogen activator receptor-related peptide-1 (SLURP-1), a positive allosteric modulator of alpha7 nAChR signaling, is down-regulated both in an animal model of asthma and in human epithelial cells treated with an inflammatory cytokine related to asthma. Our aim of this study was to explore the effect of SLURP-1, signal through alpha7 nAChR, in the pathophysiology of airway inflammation. Cytokine production was examined using human epithelial cells. Ciliary beat frequency of murine trachea was measured using a high speed camera. The IL-6 and TNF-alpha production by human epithelial cells was augmented by siRNA of SLURP-1 and alpha7 nicotinic ACh receptor. The cytokine production was also dose-dependently suppressed by human recombinant SLURP-1 (rSLURP-1). The ciliary beat frequency and amplitude of murine epithelial cells were augmented by PNU282987, a selective alpha7 nAChR agonist. Those findings suggested that SLURP-1 and stimulus through alpha7 nicotinic ACh receptors actively controlled asthmatic condition by stimulating ciliary beating and also by suppressing airway inflammation.