ACE2 in pulmonary diseases

Angiotensin converting enzyme 2 (ACE2), a relatively new member of the RAS, has drawn extensive attention since 2003, because of the findings that ACE2 is the receptor for SARS-CoV 1 and 2, and that maintenance of normal ACE2 levels in the lung is beneficial for the host to combat inflammatory lung disease. Given that ACE2 has vasodilatory, anti-inflammation, anti-fibrotic, and pro-regenerative activities, the involvement of this enzyme in many aspects of physiology and pathophysiology, especially in cardiopulmonary diseases, is rapidly evolving in the literature. In this chapter, we summarize the contribution of ACE2 signalling to the initiation and progression of lung diseases such as pulmonary hypertension, asthma, fibrosis, tumors, COPD, and other acute lung injuries as well as COVID-19. A better understanding of the role of ACE2 signalling in the pathogenesis of pulmonary diseases would offer novel approaches for the development of therapeutics to treat a variety of inflammatory disorders in respiratory and other systems.