Nicotine upregulates ACE2 expression and increases competence for SARS-CoV-2 in human pneumocytes
Fabrizio Maggi, Alfredo Rosellini, Pietro Giorgio Spezia, Daniele Focosi, Lisa Macera, Michele Lai, Mauro Pistello, Antonio de Iure, Carlo Tomino, Stefano Bonassi, Patrizia Russo
Abstract
The coronavirus disease 2019 (COVID-19) pandemic has a variable degree of severity according to underlying comorbidities and life-style. Several research groups have reported an association between cigarette smoking and increased severity of COVID-19. The exact mechanism of action is largely unclear. We exposed low angiotensin-converting enzyme 2 (ACE2)-expressing human pulmonary adenocarcinoma A549 epithelial cells to nicotine and assessed ACE2 expression at different times. We further used the nicotine-exposed cells in a virus neutralisation assay. Nicotine exposure induces rapid and long-lasting increases in gene and protein expression of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) receptor ACE2, which in turn translates into increased competence for SARS-CoV-2 replication and cytopathic effect. These findings show that nicotine worsens SARS-CoV-2 pulmonary infection and have implications for public health policies.