β2-agonists promote host defense against bacterial infection in primary human bronchial epithelial cells

• Main Authors: Weinberger Andrew R, Green Rebecca M, Bowler Russell P, Gross Claire A, Schnell Christina, Chu Hong
• Format: Article
• Language: English
• Published: BMC 2010-05-01
• Series: BMC Pulmonary Medicine
• Online Access: http://www.biomedcentral.com/1471-2466/10/30

<p>Abstract</p> <p>Background</p> <p>Airway epithelial cells are critical in host defense against bacteria including <it>Mycoplasma pneumoniae </it>(Mp) in chronic obstructive pulmonary disease (COPD) and asthma. β2-agonists are mainstay of COPD and asthma therapy, but whether β2-agonists directly affect airway epithelial host defense functions is unclear.</p> <p>Methods</p> <p>Epithelial cells from bronchial brushings of normal (n = 8), asthma (n = 8) and COPD (n = 8) subjects were grown in air-liquid interface cultures, and treated with cigarette smoke extract (CSE) and/or Th2 cytokine IL-13, followed by Mp infection and treatment with β2-agonists albuterol and formoterol for up to seven days. Mp and host defense proteins short palate, lung, and nasal epithelial clone 1 (SPLUNC1) and β-defensin-2 were quantified. Expression of β2-adrenergic receptors was also measured by real-time quantitative RT-PCR.</p> <p>Results</p> <p>(R)- or racemic albuterol and (R,R)- or racemic formoterol significantly decreased Mp levels in normal and asthma epithelial cells. Normal cells treated with Mp and (R)- or racemic albuterol showed an increase in SPLUNC1, but not in β-defensin-2. COPD cells did not respond to drug treatment with a significant decrease in Mp or an increase in SPLUNC1. IL-13 attenuated drug effects on Mp, and markedly decreased SPLUNC1 and β2-adrenergic receptors.</p> <p>Conclusions</p> <p>These results for the first time show that β2-agonists enhance host defense functions of primary bronchial epithelial cells from normal and asthma subjects, which is attenuated by IL-13.</p>