Figure 7.

Schematic model depicting the potential role of extracellular INPP4A. In normal airway physiology, extracellular INPP4A transferred from epithelial cells to fibroblasts reduces the proliferation of the latter, highlighting the role of extracellular INPP4A in maintaining a check on fibroblast growth. In allergic airways, damaged epithelium and a concomitant decrease in extracellular INPP4A may eliminate this control and lead to fibroblast hyperproliferation and airway remodeling, a key feature of asthma pathophysiology.