Particulate matter exposure exacerbates susceptibility to SARS-CoV-2 infection in humanized ACE2 mice

The global outbreak of coronavirus disease 2019(COVID-19),which is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),as of 8 May 2021,has surpassed 150700000 infections and 3279000 deaths worldwide.Evidence indicates that SARS-CoV-2 RNA can be detected on particulate matter(PM),and COVID-19 cases are correlated with levels of air pollutants.However,the mechanisms of PM involvement in the spread of SARS-CoV-2 remain poorly understood.Here,we found that PM exposure increased the expression level of angiotensin-converting enzyme 2(ACE2)and transmembrane serine protease 2(TMPRSS2)in several epithelial cells and increased the adsorption of the SARS-CoV-2 spike protein.Instillation of PM in a hACE2 mouse model significantly increased the expression of ACE2 and Tmprss2 and viral replication in the lungs.Furthermore,PM exacerbated the pulmonary lesions caused by SARS-CoV-2 infection in the hACE2 mice.In conclusion,our study demonstrated that PM is an epidemiological factor of COVID-19,emphasizing the necessity of wearing anti-PM masks to cope with this global pandemic.