Does the human placenta express the canonical cell entry mediators for SARS-CoV-2?

Abstract

The pandemic of coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected more than 10 million people, including pregnant women. To date, no consistent evidence for the vertical transmission of SARS-CoV-2 exists. The novel coronavirus canonically utilizes the angiotensin-converting enzyme 2 (ACE2) receptor and the serine protease TMPRSS2 for cell entry. Herein, building upon our previous single-cell study (Pique-Regi, 2019), another study, and new single-cell/nuclei RNA-sequencing data, we investigated the expression of ACE2 and TMPRSS2 throughout pregnancy in the placenta as well as in third-trimester chorioamniotic membranes. We report that co-transcription of ACE2 and TMPRSS2 is negligible in the placenta, thus not a likely path of vertical transmission for SARS-CoV-2. By contrast, receptors for Zika virus and cytomegalovirus, which cause congenital infections, are highly expressed by placental cell types. These data show that the placenta minimally expresses the canonical cell-entry mediators for SARS-CoV-2.

Characterizing COVID-19 maternal-fetal transmission and placental infection using comprehensive molecular pathology

“…This finding not only confirms the recent results of placental infection in other neonates with COVID-19 [ 8 , 9 ] but introduces new questions. How do these findings correlate with recent research examining the presence of receptors (ACE2) and enzymes (TMPRSS2) in placental tissues that are necessary for viral entry and replication [10] ? Do Hofbauer cells have a role in either preventing or permitting transmission?…”

Erythroid precursors and progenitors suppress adaptive immunity and get invaded by SARS-CoV-2

“…Also, CECs become abundant in the peripheral blood of pregnant women at the later stage of pregnancy 33,34,40 , which in part may support the reported viremia and placental transmission of SARS-CoV-2 60 . This was challenged due to negligible co-expression of ACE2 and TMPRSS2 by placental cell types 61 . However, mRNA expression does not necessarily correlate with the protein expression pattern.…”

Of Mice and Men: The Coronavirus MHV and Mouse Models as a Translational Approach to Understand SARS-CoV-2

“…Human placenta highly expresses ACE2 and maternal-fetal transmission by viremia was described recently [100]. However, co-transcription of ACE2 and TMPRSS2 is negligible in the placenta [101].…”