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Oral Epithelial Cells Expressing Low or Undetectable Levels of Human Angiotensin-Converting Enzyme 2 are Susceptible SARS-CoV-2Virus Infection in vitro
Ebraham, L.; Xu, C.; Wang, A.; Hernandez, C.; Siclari, N.; Rajah, D.; Walter, L.; Marras, S.A.E.; Tyagi, S.; Fine, D.H.; Daep, C.A.; Chang, T.L. Oral Epithelial Cells Expressing Low or Undetectable Levels of Human Angiotensin-Converting Enzyme 2 Are Susceptible to SARS-CoV-2 Virus Infection In Vitro. Pathogens2023, 12, 843.
Ebraham, L.; Xu, C.; Wang, A.; Hernandez, C.; Siclari, N.; Rajah, D.; Walter, L.; Marras, S.A.E.; Tyagi, S.; Fine, D.H.; Daep, C.A.; Chang, T.L. Oral Epithelial Cells Expressing Low or Undetectable Levels of Human Angiotensin-Converting Enzyme 2 Are Susceptible to SARS-CoV-2 Virus Infection In Vitro. Pathogens 2023, 12, 843.
Ebraham, L.; Xu, C.; Wang, A.; Hernandez, C.; Siclari, N.; Rajah, D.; Walter, L.; Marras, S.A.E.; Tyagi, S.; Fine, D.H.; Daep, C.A.; Chang, T.L. Oral Epithelial Cells Expressing Low or Undetectable Levels of Human Angiotensin-Converting Enzyme 2 Are Susceptible to SARS-CoV-2 Virus Infection In Vitro. Pathogens2023, 12, 843.
Ebraham, L.; Xu, C.; Wang, A.; Hernandez, C.; Siclari, N.; Rajah, D.; Walter, L.; Marras, S.A.E.; Tyagi, S.; Fine, D.H.; Daep, C.A.; Chang, T.L. Oral Epithelial Cells Expressing Low or Undetectable Levels of Human Angiotensin-Converting Enzyme 2 Are Susceptible to SARS-CoV-2 Virus Infection In Vitro. Pathogens 2023, 12, 843.
Abstract
The oral cavity is thought to be one of the portals for SARS-CoV-2 entry. Because there is limited evidence of active oral infection by SARS-CoV-2 viruses, we assessed the capacity of SARS-CoV-2 to infect and replicate in oral epithelial cells. Oral gingival epithelial cells (hTERT TIGKs), salivary gland epithelial cells (A-253), and oral buccal epithelial cells (TR146), which occupy different regions of the oral cavity, were challenged with replication competent SARS-CoV-2 viruses and with pseudo-typed viruses expressing SARS-CoV-2 spike proteins. All oral epithelial cells expressing undetectable or low levels of human angiotensin-converting enzyme 2 (hACE2) but high levels of the alternative receptor CD147 were susceptible to SARS-CoV-2 infection. Viral dynamics in hTERT TIGKs were different from those in A-253 and TR146 cells. For example, levels of viral transcripts were sustained in hTERT TIGKs but were significantly decreased in A-253 and TR146 cells at day 3 after infection. Analysis of oral epithelial cells infected by replication competent SARS-CoV-2 viruses expressing GFP showed that the signals of GFP and SARS-CoV-2 mRNAs were not evenly distributed. Taken together, our results demonstrated oral epithelial cells were susceptible to SARS-CoV-2 viruses despite of low or undetectable levels of hACE2, suggesting that alternative receptors contribute to SARS-CoV-2 infection and may be considered for development of future vaccines and therapeutics.
Keywords
SARS-CoV-2; oral epithelial cells; alternative receptors
Subject
Chemistry and Materials Science, Materials Science and Technology
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Received:
23 May 2023
Commenter's Conflict of Interests:
published a paper showing primary gingival epithelial cells are no permissive although expressing CD147.
Comment:
syncytia assay and images of cytopathic effect should be included in the case of replication competent virus. In the case of competent virus is suspicious that viral load spikes the day after infection and then decrease at 72 hours. does the FISH and the GFP tagged virus correlate with the high PCR values? PCR values are quite high in relation with the fluorescence assays. can you show 293T infection level?
You should discuss the following papers:
The commenter has declared there is no conflict of interests.
Comment:
Thank you for your feedback. The syncytia assay may not be suitable due to the inefficient infection of oral epithelial cells. We did observe altered cell morphology of infected cells and the images were included in the revised version of the manuscript. The goal of this brief report is to show that oral epithelial cells were susceptible to SARS-CoV-2 infection and we used various methods to address this question. The degree of infection of 293T cells by pseduotyped SARS-CoV-2 virus is ~10-fold higher compared to oral epithelial cells. Infection of 293T cells has been published in our previous study. Here we included 293T cells in our RT-PCR analysis of hACE2 and other receptors because the need for the reference for oral epithelial cells with the low abundance hACE. We did not include infection of 293T cells by SARS-CoV-2 in the figure to avoid the distraction. The entry mechanism of SARS-CoV-2 is complex. Different cell lines with various hACE2-dependent accessory receptors or hACE2-independent alternative receptors have not been profiled in systematic ways so we decided to focus on oral epithelial cells in the infection assays.
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Commenter's Conflict of Interests: published a paper showing primary gingival epithelial cells are no permissive although expressing CD147.
You should discuss the following papers:
DOI: 10.1111/eos.12906
https://doi.org/10.1038/s41598-020-80464-1
https://doi.org/10.3390/cells10061434
and
https://doi.org/10.1016/j.cell.2020.05.042
Commenter:
The commenter has declared there is no conflict of interests.