Airway epithelial-to-mesenchymal transition: Compartmentalized cyclic AMP

Epithelial-to-mesenchymal transition EMT is characterized by a reduction of the epithelial cell marker E-cadherin and gain of the mesenchymal marker collagen. EMT plays a critical role in pulmonary fibrosis1. The phosphodiesterase PDE4 inhibitor rolipram has been shown to inhibit transforming growth factor beta 1 TGF-beta1 mediated EMT in A549 cells implicating that cAMP is able to attenuate EMT-associated lung diseases2. Signaling by cAMP encompasses compartmentalization via A-kinase anchoring proteins AKAPs. The role of AKAPs and its therapeutic value in EMT is still barely understood.