{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,24]],"date-time":"2026-09-24T10:54:26Z","timestamp":1790247266019,"version":"4.1.0"},"update-to":[{"DOI":"10.12688\/wellcomeopenres.20514.1","type":"new_version","label":"New version","source":"publisher","updated":{"date-parts":[[2024,11,22]],"date-time":"2024-11-22T00:00:00Z","timestamp":1732233600000}}],"reference-count":76,"publisher":"F1000 Research Ltd","license":[{"start":{"date-parts":[[2024,11,22]],"date-time":"2024-11-22T00:00:00Z","timestamp":1732233600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000781","name":"European Research Council","doi-asserted-by":"publisher","award":["646891"],"award-info":[{"award-number":["646891"]}],"id":[{"id":"10.13039\/501100000781","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000265","name":"Medical Research Council","doi-asserted-by":"publisher","award":["MR\/R021821\/1"],"award-info":[{"award-number":["MR\/R021821\/1"]}],"id":[{"id":"10.13039\/501100000265","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000268","name":"Biotechnology and Biological Sciences Research Council","doi-asserted-by":"publisher","award":["BB\/V017780\/1"],"award-info":[{"award-number":["BB\/V017780\/1"]}],"id":[{"id":"10.13039\/501100000268","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100004440","name":"Wellcome","doi-asserted-by":"publisher","award":["216370"],"award-info":[{"award-number":["216370"]}],"id":[{"id":"10.13039\/100004440","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100004440","name":"Wellcome","doi-asserted-by":"publisher","award":["106207"],"award-info":[{"award-number":["106207"]}],"id":[{"id":"10.13039\/100004440","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100004440","name":"Wellcome","doi-asserted-by":"publisher","award":["204464"],"award-info":[{"award-number":["204464"]}],"id":[{"id":"10.13039\/100004440","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100004440","name":"Wellcome","doi-asserted-by":"publisher","award":["220814"],"award-info":[{"award-number":["220814"]}],"id":[{"id":"10.13039\/100004440","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100004440","name":"Wellcome","doi-asserted-by":"publisher","award":["215226"],"award-info":[{"award-number":["215226"]}],"id":[{"id":"10.13039\/100004440","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004815","name":"Isaac Newton Trust","doi-asserted-by":"publisher","award":["G101522"],"award-info":[{"award-number":["G101522"]}],"id":[{"id":"10.13039\/501100004815","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["wellcomeopenresearch.org"],"crossmark-restriction":false},"short-container-title":["Wellcome Open Res"],"abstract":"<ns3:p>\n                    Background Infection during pregnancy with SARS-CoV-2 can have a serious impact on both maternal and foetal health. Clinical studies have shown that SARS-CoV-2 transmission from the mother to the foetus typically does not occur. However, there is evidence that SARS-CoV-2 can infect the placenta\n                    <ns3:italic>in utero<\/ns3:italic>\n                    . Here we sought to quantify the permissiveness of placental cells to SARS-CoV-2 infection and to determine if they support viral release. Methods By using publicly available single-cell RNA sequencing (scRNAseq) data sets and confocal microscopy we compared ACE2 transcript and protein expression across human first trimester and term placental cells. We also used\n                    <ns3:italic>in vitro<\/ns3:italic>\n                    infection assays to quantify the infection rates of a range of placenta-derived cells. Finally, we quantified the viral egress from these cells. Results ACE2 transcripts are found in a range of placental cell types across gestation, including trophoblast. However, ACE2 protein expression does not significantly change across placental cell types from first trimester to term. We find that 0.5\u00b10.15 % of term trophoblast cells can be infected with SARS-CoV-2 while primary placental fibroblasts and macrophages, and JEG-3, JAR and HUVEC cell lines are resistant to infection. Furthermore, primary trophoblast cells poorly support viral release while JEG-3 cells allow relatively high levels of viral release. Conclusions The low level of viral release by primary placental cells provides insight into how the virus is impaired from crossing the placenta to the foetus.\n                  <\/ns3:p>","DOI":"10.12688\/wellcomeopenres.20514.2","type":"journal-article","created":{"date-parts":[[2024,11,22]],"date-time":"2024-11-22T13:25:07Z","timestamp":1732281907000},"page":"209","update-policy":"https:\/\/doi.org\/10.12688\/wellcomeopenres.crossmark-policy","source":"Crossref","is-referenced-by-count":3,"title":["Human placental cells are resistant to SARS-CoV-2 infection and replication"],"prefix":"10.12688","volume":"9","author":[{"given":"Nagisa","family":"Yoshida","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jake 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Y.W.","family":"Chung","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5200-2698","authenticated-orcid":false,"given":"Naomi","family":"McGovern","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1438-1089","authenticated-orcid":false,"given":"Hazel","family":"Stewart","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"2560","published-online":{"date-parts":[[2024,11,22]]},"reference":[{"key":"ref-1","doi-asserted-by":"publisher","DOI":"10.1186\/s12916-020-01798-1","article-title":"Pregnant women with COVID-19 and risk of adverse birth outcomes and maternal-fetal vertical transmission: a population-based cohort study in Wuhan, China.","volume":"18","author":"R Yang","year":"2020","journal-title":"BMC 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Research"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/wellcomeopenresearch.org\/articles\/9-209\/v2\/xml","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/wellcomeopenresearch.org\/articles\/9-209\/v2\/pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/wellcomeopenresearch.org\/articles\/9-209\/v2\/iparadigms","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,12,4]],"date-time":"2024-12-04T02:45:12Z","timestamp":1733280312000},"score":1,"resource":{"primary":{"URL":"https:\/\/wellcomeopenresearch.org\/articles\/9-209\/v2"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,11,22]]},"references-count":76,"URL":"https:\/\/doi.org\/10.12688\/wellcomeopenres.20514.2","relation":{"has-version":[{"id-type":"doi","id":"10.12688\/wellcomeopenres.20514.1","asserted-by":"subject"}],"has-review":[{"id-type":"doi","id":"10.21956\/wellcomeopenres.25762.r112957","asserted-by":"subject"},{"id-type":"doi","id":"10.21956\/wellcomeopenres.25762.r115777","asserted-by":"object"},{"id-type":"doi","id":"10.21956\/wellcomeopenres.25762.r113127","asserted-by":"object"},{"id-type":"doi","id":"10.21956\/wellcomeopenres.25762.r112957","asserted-by":"object"}]},"ISSN":["2398-502X"],"issn-type":[{"value":"2398-502X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,11,22]]},"assertion":[{"value":"Indexed","URL":"https:\/\/wellcomeopenresearch.org\/articles\/9-209\/v2#article-reports","order":0,"name":"referee-status","label":"Referee status","group":{"name":"current-referee-status","label":"Current Referee Status"}},{"value":"10.21956\/wellcomeopenres.22708.r84519, Connor Bamford, Queen's University Belfast, Belfast, 14 Jun 2024, version 1, 1 approved, 1 approved with reservations","URL":"https:\/\/wellcomeopenresearch.org\/articles\/9-209\/v1#referee-response-84519","order":0,"name":"referee-response-84519","label":"Referee Report","group":{"name":"article-reports","label":"Article Reports"}},{"value":"<b>Naomi McGovern<\/b>; \n<i>Posted: 30 Oct 2024<\/i>; We thank the reviewer for their insightful comments \n<b>Review:<\/b> A focused in vitro study looking at in vitro infection and release with a very early isolate of SARS2 in reference to expression of two key entry factors, ACE2\/TMPRSS2. They find that primary placental cells have reduced susceptibility to infection than controls likely due to expression less receptors. However, a commonly used placental cell line, JEG-3 can be infected and release infectious virus, unlike primary counterparts suggesting it is a poor model for placental infection biology.  \n<b>Abstract:<\/b> Abstract needs attention as not broken adequately into required sections (E.g. some methods not introduced in methods section and method section currently has results).  Abstract and title should be clearer that this study is focused on in vitro experiments \n<b>Response:&nbsp;<\/b>Thanks for highlighting this error. We have amended the Abstract as requested.  \n<b>Introduction:<\/b> Increased risk factor for \n<i>reduced<\/i> maternal and foetal health? \n<b>Response:&nbsp;<\/b>This omission has been added.  Define COVID-19 \n<b>Response:&nbsp;<\/b>We have added to the introduction \u201cCoronavirus Disease 2019 (COVID-19) is a highly contagious respiratory illness caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)\u201d  What is rationale for only focusing on certain entry dependency factors and not considering other genes, especially known inhibitors of infection? \n<b>Response:&nbsp;<\/b>In the Discussion we explain \u201cSuccessful infection of a host cell depends on the presence of various surface host proteins, including but not limited to ACE2 and TMPRSS2. Following ACE2 engagement, S2\u2019 site cleavage may be mediated by TMPRSS2 (allowing entry at the cell surface) or other proteases including cathepsin L, after endocytosis of the virion (reviewed in\n<sup>21<\/sup>). Given the extremely low levels of TMPRSS2 expression which we observed (Figure 1H), it is possible that any entry in placental tissue is mediated by this latter pathway, although this study did not aim to elucidate which entry route was being utilised.\u201d  \n<b>Methods:<\/b> Is anything known about biological characteristics of placental donors, such as ethnicity or age? \n<b>Response:&nbsp;<\/b>We explain in the Methods that \u201cPlacentas were obtained from healthy women with apparently normal pregnancies undergoing elective first trimester terminations (6-12 weeks estimated gestational age (EGA) (n=20)). Term placentas were collected from healthy women with normal pregnancies and delivered by elective Cesarean section\u201d. The ethnicity and age of the donors have not been recorded.  \n<b>Results:<\/b> Have the gene expression results taken into consideration ACE2 splice variants? \n<b>Response:&nbsp;<\/b>No, the results have not taken into consideration splice variants. We have noted this is a limitation of the study in the Discussion.  \n<b>Discussion:<\/b> Be explicit about what you mean by SARS-CoV-2 has been found in placental tissue \u2013 is this RNA, infectious virus, infected cells, virions?  Discuss the variability within individuals that is greater than other comparisons. We have added to the Discussion that the small sample size is a limitation of the study.  It would have been helpful to include a virus control for cell infectivity to know if these cultures are truly viable. \n<b>Response:&nbsp;<\/b>We used established culture protocols for primary placental cells\n<sup> 22\u201324<\/sup>. This been more clearly explained in the Method section. References: &nbsp; 1. Apps, R. \n<i>et al.<\/i> Genome-wide expression profile of first trimester villous and extravillous human trophoblast cells. \n<i>Placenta<\/i> 32, 33\u201343 (2011). 2. Kumar, S. \n<i>et al.<\/i> Proteomic Analysis Identifies Molecular Players and Biological Processes Specific to SARS-CoV-2 Exposure in Endothelial Cells. (2022) doi:10.3390\/ijms231810452. 3. Schimmel, L. \n<i>et al.<\/i> Endothelial cells are not productively infected by SARS-CoV-2. \n<i>Clin Transl Immunology<\/i> (2021) doi:10.1002\/cti2.1350. 4. Agostinis, C. \n<i>et al.<\/i> SARS-CoV-2 modulates virus receptor expression in placenta and can induce trophoblast fusion, inflammation and endothelial permeability. (2022) doi:10.3389\/fimmu.2022.957224. 5. Dicken, S. J. \n<i>et al.<\/i> Characterisation of B.1.1.7 and Pangolin coronavirus spike provides insights on the evolutionary trajectory of SARS-CoV-2. \n<i>BioRxiv<\/i> (2021) doi:10.1101\/2021.03.22.436468. 6. Zhang, J. \n<i>et al.<\/i> Membrane fusion and immune evasion by the spike protein of SARS-CoV-2 Delta variant. \n<i>Science (1979)<\/i> 374, 1353\u20131360 (2021). 7. Mlcochova, P. \n<i>et al.<\/i> SARS-CoV-2 B.1.617.2 Delta variant replication and immune evasion. \n<i>Nature<\/i> 599, 114\u2013119 (2021). 8.Shook, L. L. \n<i>et al.<\/i> SARS-CoV-2 Placentitis Associated With B.1.617.2 (Delta) Variant and Fetal Distress or Demise. \n<i>J Infect Dis<\/i> 225, 754\u2013758 (2022). 9. Knight, M. \n<i>et al.<\/i> Open access Original research Severity of maternal infection and perinatal outcomes during periods of SARS-CoV-2 wildtype, alpha, and delta variant dominance in the UK: prospective cohort study. 1, 53 (2022). 10. DeSisto, C. L. \n<i>et al.<\/i> Risk for Stillbirth Among Women With and Without COVID-19 at Delivery Hospitalization \u2014 United States, March 2020\u2013September 2021. \n<i>MMWR Morb Mortal Wkly Rep<\/i> 70, 1640\u20131645 (2021). 11.&nbsp; Shanes, E. D. \n<i>et al.<\/i> Placental Pathology After SARS-CoV-2 Infection in the Pre-Variant of Concern, Alpha \/ Gamma, Delta, or Omicron Eras. \n<i>Int J Surg Pathol<\/i> 31, 387\u2013397 (2023). 12. Zhang, J. \n<i>et al.<\/i> Membrane fusion and immune evasion by the spike protein of SARS-CoV-2 Delta variant. \n<i>Science (1979)<\/i> 374, 1353\u20131360 (2021). 13.&nbsp; Lanahan, M. R., Maples, R. W. &amp; Pfeiffer, J. K. Tradeoffs for a viral mutant with enhanced replication speed. \n<i>Proceedings of the National Academy of Sciences<\/i> 118, (2021). 14. Shi, G. \n<i>et al.<\/i> Opposing activities of IFITM proteins in SARS\u2010CoV\u20102 infection. \n<i>EMBO J<\/i> 40, (2021). 15.Stewart, H. \n<i>et al.<\/i> Tetherin antagonism by SARS\u2010CoV \u20102 ORF3a and spike protein enhances virus release. \n<i>EMBO Rep<\/i> 24, (2023). 16.&nbsp; &nbsp; &nbsp; &nbsp;Martin-Sancho, L. \n<i>et al.<\/i> Functional landscape of SARS-CoV-2 cellular restriction. \n<i>Mol Cell<\/i> 81, 2656-2668.e8 (2021). 17. DeBiasi, R. L. Severe Acute Respiratory Syndrome-Coronavirus-2 Effects at the Maternal-Fetal Interface. \n<i>J Infect Dis<\/i> 225, 745\u2013747 (2022). 18. Guan, M. \n<i>et al.<\/i> Intrauterine Fetal Demise in the Third Trimester of Pregnancy Associated With Mild Infection With the SARS-CoV-2 Delta Variant Without Protection From Vaccination. \n<i>J Infect Dis<\/i> 225, 748\u2013753 (2022). 19. Megli, C. J. &amp; Coyne, C. B. Infections at the maternal\u2013fetal interface: an overview of pathogenesis and defence. \n<i>Nat Rev Microbiol<\/i> 20, 67\u201382 (2022). 20.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Boyd, J. D. &amp; Hamilton, W. J. \n<i>The Human Placenta<\/i>. \n<i>Nursing mirror and midwives journal<\/i> vol. 134 (Nurs Mirror Midwives J, 1972). 21. Jackson, C. B., Farzan, M., Chen, B. &amp; Choe, H. Mechanisms of SARS-CoV-2 entry into cells. \n<i>Nat Rev Mol Cell Biol<\/i> 23, 3\u201320 (2022). 22. Thomas, J. R. \n<i>et al.<\/i> Primitive haematopoiesis in the human placenta gives rise to macrophages with epigenetically silenced HLA-DR. \n<i>Nat Commun<\/i> 14, 1764 (2023). 23.&nbsp; Aye, I. L. M. H., Jansson, T. &amp; Powell, T. L. Interleukin-1\u03b2 inhibits insulin signaling and prevents insulin-stimulated system A amino acid transport in primary human trophoblasts. \n<i>Mol Cell Endocrinol<\/i> 381, 46\u201355 (2013). 24.&nbsp; Sheridan, M. A. \n<i>et al.<\/i> Characterization of primary models of human trophoblast. (2021) doi:10.1242\/dev.199749 .","URL":"https:\/\/wellcomeopenresearch.org\/articles\/9-209\/v2#referee-comment-5881","order":1,"name":"referee-comment-5881","label":"Referee Comment","group":{"name":"article-reports","label":"Article Reports"}},{"value":"10.21956\/wellcomeopenres.25762.r112957, Joan R\u00f6hl, Faculty of Health Sciences and Medicine, Bond University, Robina, Queensland, 04 Dec 2024, version 2, indexed","URL":"https:\/\/wellcomeopenresearch.org\/articles\/9-209\/v2#referee-response-112957","order":2,"name":"referee-response-112957","label":"Referee Report","group":{"name":"article-reports","label":"Article Reports"}},{"value":"This work is supported by Wellcome (204464, a Sir Henry Dale Fellowship award to N.McG; 215226, a Wellcome Trust PhD Studentship award to J.T.; 106207, 220814, Wellcome Trust Senior Research Fellowships awarded to A.F.). J.R.E. is supported by a Sir Henry Dale Fellowship jointly funded by Wellcome and the Royal Society (216370). N.McG and N.Y. are funded by a Ferring COVID-19 Investigational Grant. B.Y.W.C. and M.B. are funded by a Medical Research Council Fellowship (MR\/R021821\/1), Biotechnology and Biological Sciences Research Council COVID response grant (BB\/V017780\/1) and the Isaac Newton Trust (G101522). I.A. is funded by the Centre for Trophoblast Research Next Generation Fellowship. H.S. and A.F. are funded by a European Research Council Consolidator Grant (646891). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.","order":3,"name":"grant-information","label":"Grant Information"},{"value":"This is an open access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.","order":0,"name":"copyright-info","label":"Copyright"}]}}