ACE2 and severe acute respiratory syndrome: Interestingly, NOX4-derived ROS production has been shown to be modulated by Angiotensin-Converting Enzyme 2 (ACE2) [14], that is known to be the main receptor of severe acute respiratory syndrome-coronavirus (SARS-CoV) and now identified also as the key receptor for the novel SARS-CoV-2, cause of the recent respiratory syndrome COVID-19 [15].