Ozone Exposure Alters MicroRNA Expression Profiles in Humans

We set out to test the hypothesis that ozone inhalation exposure significantly alters miRNA expression profiles within the airway of humans. Adult human volunteers were exposed to 0.4 ppm ozone for two hours. Induced sputum samples were collected from each subject 48 hours pre-exposure and 6 hours post-exposure. Genome-wide miRNA expression profiles were evaluated using microarray analysis. Twenty healthy non-asthmatic adult subjects aged 18 – 37 years, with no history of smoking in the past 10 years, completed the study. The ozone exposures were conducted in an exposure chamber. Each subject was exposed to 0.4 ppm ozone for two hours while performing four 15-minute sessions of intermittent moderate exercise (expiratory minute ventilation, 30–40 L/min) on a treadmill, separated by 15 minutes of seated rest. Induced sputum samples were collected from each subject 48 hours pre-exposure and 6 hours post-exposure. RNA samples were homogenized in TRIzol, and extracted according to standard TRIzol protocol. RNA was labeled and hybridized to the Agilent Human miRNA Microarray (v1.0).