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在全球肆虐的严重急性呼吸综合征冠状病毒2(severe acute respiratory syndrome coronavirus 2,SARS-CoV-2)导致了大量人群感染,血管紧张素转化酶2(angiotensin-converting enzyme 2,ACE2)是SARS-CoV和SARS-CoV-2的受体蛋白.然而是否存在SARS-CoV-2的垂直传播仍颇有争议.为了探讨SARS-CoV-2垂直传播的潜在风险,我们利用已发表的单细胞转录组数据观察了围着床期胚胎和母胎界面上ACE2和TMPRSS2(编码跨膜丝氨酸蛋白酶2)的转录表达情况.结果显示,ACE2和TMPRSS2在第6天(D6)围着床期胚胎的滋养外胚层(trophectoderm,TE)细胞、妊娠第8周的合胞滋养层(syncytiotrophoblast at 8 weeks of gestation,STB_8W)细胞以及妊娠第24周的绒毛外滋养层(extravillous trophoblasts at 24 weeks of gestation,EVT_24W)细胞中均存在明显的共表达现象,表明这些细胞类群可能易被SARS-CoV-2感染.在这三个细胞类群中,ACE2阳性表达细胞相对于阴性细胞在自噬和免疫相关过程中存在差异.尽管ACE2的表达水平在围着床期胚胎中没有表现出性别偏差,但是其在D6 TE、第6天围着床期胚胎的原始内胚层(D6 primitive endoderm,D6 PE)细胞以及ACE2阳性表达的STB细胞中存在明显的性别差异.这表明围着床期发育第6天以及妊娠期胚胎对SARS-CoV-2的易感性可能存在性别差异.我们的结果揭示了胚胎移植过程中,围着床期以及妊娠期胚胎面临着SARS-CoV-2的潜在感染风险.“,”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 inter-face, 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 charac-teristics, 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 gesta-tion of different genders. Our results reveal potential SARS-CoV-2 infection risks during embryo transfer, peri-implantation embryo development, and gestation.