The airway smooth muscle in asthma: More than meets the eye

Asthma is a chronic, episodic inflammatory disease of the airways characterized by airway remodeling and functional changes including variable airways obstruction and bronchial hyperresponsiveness. The pathophysiologic mechanisms leading to the functional changes in asthma are still largely unknown. However, recent studies suggest that the airway smooth (ASM) layer in the airway wall is a key player in determining the clinical expression of asthma. Additionally, the ASM layer itself may also contribute to the regulation and perpetuation of airways inflammation and remodeling in asthma. These data suggest that the gene expression of the ASM layer in asthma is changed as well. The studies included in this thesis were aimed at elucidating the role of ASM in the pathophysiology of asthma. Additionally, we aimed to clarify whether the beneficial effects of glucocorticoids on the clinical status and lung function of asthma patients are solely based on its anti-inflammatory properties or whether they also exert other local actions on the ASM layer. For these purposes we examined the composition and gene expression profile of the ASM layer in asthma in association with airway function by next-generation high-throughput gene sequencing (RNA-Seq).