Angiotensin-Converting Enzyme 2/Angiotensin-(1-7)/Mas Receptor Axis: Emerging Pharmacological Target for Pulmonary Diseases

Experimental and clinical evidence supports an active role of the renin–angiotensin system (RAS) in the pathogenesis and progression of lung diseases. Angiotensin II (Ang II), a key vasoactive peptide of the RAS, has been implicated in pulmonary disorders such as pulmonary arterial hypertension, lung fibrosis, chronic obstructive pulmonary disease, and acute respiratory distress syndrome. Over the past few years, the classical concept of the RAS has undergone substantial changes to include several new active components. Among them, the identification of angiotensin-converting enzyme 2 (ACE2), its metabolic product angiotensin-(1-7) (Ang-(1-7)), and the Mas receptor has been of biological significance since these components form a counterregulatory axis (ACE2/Ang-(1-7)/Mas) that opposes the detrimental actions of Ang II. In this chapter, we will discuss the role of the ACE2/Ang-(1-7)/Mas axis in lung diseases and describe novel therapeutic approaches to activate this axis for the treatment of pulmonary disorders.