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
Nicotine upregulates ACE2 expression and increases competence for SARS-CoV-2 in human pneumocytes