SARS-CoV-2 Entry Factors: ACE2 and TMPRSS2 Are Expressed in Peri-Implantation Embryos and the Maternal–Fetal Interface

• Main Authors: Wei Chen, Peng Yuan, Ming Yang, Zhiqiang Yan, Siming Kong, Jie Yan, Xixi Liu, Yidong Chen, Jie Qiao, Liying Yan
• Format: Article
• Language: English
• Published: Elsevier 2020-10-01
• Series: Engineering
• Subjects: SARS-CoV-2; ACE2; Vertical transmission; Placenta; Peri-implantation
• Online Access: http://www.sciencedirect.com/science/article/pii/S2095809920302162

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread throughout the world, leading to large-scale population infection. Angiotensin-converting enzyme 2 (ACE2) is the receptor of both severe acute respiratory syndrome coronavirus (SARS-CoV) and SARS-CoV-2. However, it is still controversial whether vertical transmission exists. In order to investigate the potential risk of SARS-CoV-2 vertical transmission, we explored ACE2 and TMPRSS2 (encoding transmembrane protease serine 2) expression patterns in peri-implantation embryos and the maternal–fetal interface using previously published single-cell transcriptome data. The results showed that day 6 (D6) trophectoderm (TE) cells in peri-implantation embryos, as well as syncytiotrophoblast (STB) at 8 weeks of gestation (STB_8W) and extravillous trophoblast (EVT) cells at 24 weeks of gestation (EVT_24W) in the maternal–fetal interface, strongly co-expressed ACE2 and TMPRSS2, indicating a SARS-CoV-2 infection susceptibility. The ACE2 positive-expressing cells in the three cell types mentioned above were found to share common characteristics, which were involved in autophagy and immune-related processes. ACE2 showed no gender bias in post-implantation embryos but showed a significant gender difference in D6_TE, D6 primitive endoderm (PE) cells, and ACE2 positive-expressing STBs. These findings suggest that there may be different SARS-CoV-2 infection susceptibilities of D6 embryos of different genders and during the gestation of different genders. Our results reveal potential SARS-CoV-2 infection risks during embryo transfer, peri-implantation embryo development, and gestation.