Abstract
Despite occasional reports of vertical transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during pregnancy, the question of placental infection and its consequences for the newborn remain unanswered. Herein, we analyzed the placentas of 31 coronavirus disease 2019-positive mothers by reverse transcriptase PCR, immunohistochemistry, and in situ hybridization. Only one case of placental infection was detected, which was associated with intrauterine demise of the fetus. Differentiated primary trophoblasts were then isolated from nonpathologic human placentas at term, differentiated, and exposed to SARS-CoV-2 virions. Unlike for positive control cells Vero E6, the virus inside cytotrophoblasts and syncytiotrophoblasts or in the supernatant 4 days after infection was undetectable. As a mechanism of defense, we hypothesized that trophoblasts at term do not express angiotensin-converting enzyme 2 and transmembrane protease serine 2 (TMPRSS2), the two main host membrane receptors for SARS-CoV-2 entry. The quantification of these proteins in the placenta during pregnancy confirmed the absence of TMPRSS2 at the surface of the syncytium. Surprisingly, a transiently induced experimental expression of TMPRSS2 did not allow the entry or replication of the virus in differentiated trophoblasts. Altogether, these results underline that trophoblasts are not likely to be infected by SARS-CoV-2 at term, but raise concern about preterm infection.
【저자키워드】 TMPRSS2, 【초록키워드】 coronavirus disease, SARS-CoV-2, immunohistochemistry, coronavirus, Placenta, Infection, Transmission, protease, severe acute respiratory syndrome Coronavirus, virus, angiotensin-converting enzyme 2, Replication, Protein, Newborn, Pregnancy, membrane, fetus, vertical transmission, syncytium, receptor, reverse transcriptase PCR, transmembrane protease serine 2, quantification, expression, mechanism, In situ hybridization, mother, Angiotensin-converting enzyme, angiotensin, Placental infection, Vero E6, during pregnancy, reverse transcriptase, acute respiratory syndrome, Serine, acute respiratory syndrome coronavirus, acute respiratory syndrome coronavirus 2, enzyme, SARS-CoV-2 entry, transmembrane, demise, positive control, SARS-CoV-2 virions, term, Defense, supernatant, Placentas, serine 2, Host, Cell, consequence, Pregnancy confirmed, raise, analyzed, question, absence, not express, undetectable, 【제목키워드】 coronavirus 2, clinical, respiratory,