Changes in Expression of Genes Regulating Airway Inflammation Following a High-Fat Mixed Meal in Asthmatics

Consumption of a high fat meal can increase neutrophilic airway inflammation in asthma subjects. This study investigates the molecular mechanisms driving airway neutrophilia following a high fat meal in asthmatics. Subjects with asthma (n = 11) and healthy controls (n = 8) consumed a high-fat/energy meal, containing total energy (TE) of 3846 kJ and 48 g of total fat (20.5 g saturated). Sputum was induced at 0 and 4 h, and gene expression was examined by microarray and quantitative real-time PCR (qPCR). Following the high fat dietary challenge, 168 entities were significantly differentially expressed greater than >1.5 fold in subjects with asthma, whereas, in healthy controls, only 14 entities were differentially expressed. Of the 168 genes that were changed in asthma, several biological processes were overrepresented, with 25 genes involved in "immune system processes". qPCR confirmed that S100P, S100A16, MAL and MUC1 were significantly increased in the asthma group post-meal. We also observed a strong correlation and a moderate correlation between the change in NLRP12 and S100A16 gene expression at 4 h compared to baseline, and the change in total and saturated non-esterified plasma fatty acid levels at 2 h compared to baseline. In summary, our data identifies differences in inflammatory gene expression that may contribute to increased airway neutrophilia following a high fat meal in subjects with asthma and may provide useful therapeutic targets for immunomodulation. This may be particularly relevant to obese asthmatics, who are habitually consuming diets with a high fat content.