Human Pre-Implantation Embryos Are Permissive to SARS-CoV-2 Entry

Montano, Mauricio; Victor, Andrea R.; Griffin, Darren K.; Duong, Tommy; Bolduc, Nathalie; Farmer, Andrew; Garg, Vidur; Hadjantonakis, Anna-Katerina; Barnes, Frank L.; Zouves, Christo G.; Greene, Warner C.; Viotti, Manuel

Vertical transmission of SARS-CoV-2, the virus responsible for COVID-19, from parents to early embryos during conception could be catastrophic, but is contingent on the susceptibility of cells of the embryo to infection. Because presence of the SARS-CoV-2 virus has been reported in the human reproductive system, we assessed whether pre-implantation embryos are permissive to SARS-CoV-2 entry. RNA-seq and immunostaining studies revealed presence of two key entry factors in the trophectoderm of blastocyst-stage embryos, the ACE2 receptor and the TMPRSS2 protease. Exposure of blastocysts to fluorescent reporter virions pseudotyped with the SARS-CoV-2 Spike (S) glycoprotein revealed S-ACE2 dependent entry and fusion. These results indicate that human pre-implantation embryos can be infected by SARS-CoV-2, a finding pertinent to natural human conceptions and assisted reproductive technologies during and after the COVID-19 pandemic.