F2RL1 and asthma: PAR2-mediated activation of airway epithelial cells has been reported to release a number of factors that play important roles in asthma pathogenesis (Figure 1); these factors include remodeling proteases such as matrix metalloproteases (21), the neutrophil chemotactic factor IL-8 (22, 32–34), IL-6 (22, 35, 36), GM-CSF that affects multiple innate and adaptive immune cells (36, 37), the Th2 polarizing mediators TSLP (38, 39) and IL-25 (40) and various chemokines such as eotaxin (37, 41) and CCL-2 (42).