Author:
Agrawal A.,Rengarajan S.,Adler K. B.,Ram A.,Ghosh B.,Fahim M.,Dickey B. F.
Abstract
Allergic asthma is associated with airway epithelial cell mucous metaplasia and mucin hypersecretion, but the consequences of mucin hypersecretion on airway function are unclear. Recently, a peptide derived from the myristoylated alanine-rich C kinase substrate protein NH2-terminal sequence (MANS) was shown to inhibit methacholine (MCh)-induced mucin secretion from airway mucous cells by >90%. We studied the effect of intranasal pretreatment with this peptide on specific airway conductance (sGaw) during challenge with MCh in mice with allergen-induced mucous cell metaplasia. sGaw was noninvasively measured in spontaneously breathing restrained mice, using a double-chamber plethysmograph. Pretreatment with MANS peptide, but not a control peptide [random NH2-terminal sequence (RNS)], resulted in partial inhibition of the fall in sGaw induced by 60 mM MCh (mean ± SE; baseline 1.15 ± 0.06; MANS/MCh 0.82 ± 0.05; RNS/MCh 0.55 ± 0.05 cmH2O/s). The protective effect of MANS was also seen in mice challenged with allergen for 3 consecutive days to increase airway hyperresponsiveness, although the degree of protection was less (baseline 1.1 ± 0.08; MANS/MCh, 0.65 ± 0.06; RNS/MCh 0.47 ± 0.03 cmH2O/s). Because routine sGaw measurement in mice includes nasal airways, the effectiveness of MANS was also confirmed in mice breathing through their mouths after nasal occlusion (baseline 0.92 ± 0.05; MANS/MCh 0.83 ± 0.06; RNS/MCh 0.61 ± 0.03 cmH2O/s). In all instances, sGaw in the MANS-pretreated group was ∼35% higher than in RNS-treated controls, and mucous obstruction accounted for ∼50% of the MCh-induced fall in sGaw. In summary, mucin secretion has a significant role in airway obstruction in a mouse model of allergic asthma, and strategies to inhibit mucin secretion merit further investigation.
Publisher
American Physiological Society
Subject
Physiology (medical),Physiology
Cited by
64 articles.
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