Inhaled diesel exhaust alters plasma proteome signature

Introduction: Diesel exhaust (DE), a paradigm for traffic-related air pollution, is associated with respiratory and cardiovascular diseases. The aim of this study was to define changes in global proteins (proteome) in plasma following exposure to inhaled DE, using a controlled human exposure study. Methods: Ex-smokers (n=6) inhaled filtered air (FA) and DE (300 mg PM2.5/m3) for 2h (crossover; random order). Plasma was obtained 24h after each exposure. Plasma (n=12) were probed in Slow off-rate modified aptamer (SOMAmer®)-based proteomic array. Differential analysis with Welch’s t-test was used to identify proteins significantly altered by inhaled DE compared to FA. Abundance of selected proteins were independently quantified using ELISA or immunoblots, in plasma obtained from healthy individuals following DE and FA exposure, to further validate proteins enhanced by DE. Results: 342 plasma proteins were significantly altered by DE compared to FA (Fig. 1). The top 20 proteins enhanced by DE were enriched to GO biological process of immune response; inflammation or cardiovascular disease. Conclusion: This is the first comprehensive interrogation of the plasma proteome to identify proteins altered following inhaled DE exposure in humans, and adds functional plausibility to observations of adverse health effects therein.