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Oral Mucosa Shows High Expression of ACE2 Receptor of 2019-nCoV
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- The common symptoms of COVID-19 at illness onset are fever, fatigue, dry cough, myalgia, and dyspnea. In addition, some patients might suffer from headache, dizziness, abdominal pain, diarrhea, nausea, and vomiting. A group of researchers indicated that a particular cell receptor (angiotensin-converting enzyme II; ACE2) is likely the cell receptor of the COVID-19 virus, which is also the receptor of SARS-CoV and HCoV-NL63. The authors reported the expression of the ACE2 receptor on the oral mucosa, and a highly enriched expression was observed in the epithelial cells of the tongue.
- These findings indicate that the mucosa of oral cavity may be a potentially high-risk route of COVID-19 infection.
– Luiz Meirelles, DDS, MS, PhD
abstract
This abstract is available on the publisher's site.
Access this abstract nowIt has been reported that ACE2 is the main host cell receptor of 2019-nCoV and plays a crucial role in the entry of virus into the cell to cause the final infection. To investigate the potential route of 2019-nCov infection on the mucosa of oral cavity, bulk RNA-seq profiles from two public databases including The Cancer Genome Atlas (TCGA) and Functional Annotation of The Mammalian Genome Cap Analysis of Gene Expression (FANTOM5 CAGE) dataset were collected. RNA-seq profiling data of 13 organ types with para-carcinoma normal tissues from TCGA and 14 organ types with normal tissues from FANTOM5 CAGE were analyzed in order to explore and validate the expression of ACE2 on the mucosa of oral cavity. Further, single-cell transcriptomes from an independent data generated in-house were used to identify and confirm the ACE2-expressing cell composition and proportion in oral cavity. The results demonstrated that the ACE2 expressed on the mucosa of oral cavity. Interestingly, this receptor was highly enriched in epithelial cells of tongue. Preliminarily, those findings have explained the basic mechanism that the oral cavity is a potentially high risk for 2019-nCoV infectious susceptibility and provided a piece of evidence for the future prevention strategy in dental clinical practice as well as daily life.
Additional Info
Disclosure statements are available on the authors' profiles:
High Expression of ACE2 Receptor of 2019-nCoV on the Epithelial Cells of Oral Mucosa
Int J Oral Sci 2020 Feb 24;12(1)8, H Xu, L Zhong, J Deng, J Peng, H Dan, X Zeng, T Li, Q ChenFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
The lock and key paradigm has been used to describe the activation of a receptor by only certain molecules or “keys” that fit the “lock” or receptor. A recent study reported that the angiotensin-converting enzyme 2 (ACE2) receptor, is thought to be the functional receptor (the lock) for the COVID-19 virus (the key).1 The ACE2 receptor is well known as a key target for regulating blood pressure.
The current study and others found that the ACE2 receptor is highly expressed in various body organs. The current study highlights its expression in the nasal and oral mucosa, especially the tongue. These organs could be at potentially high-risk for COVID-19 infection (Figure). This study explored two public genome data bases and performed single-cell transcriptomic analysis to examine and validate the expression of the ACE2 receptor on oral mucosal tissues; the tongue more than buccal and gingival tissues and on epithelial cells and lymphocytes. Because high expression of the ACE2 receptor was also found in the colon, consistent with other reports of GI involvement in COVID-19 infection; a fecal-oral route of transmission might also be possible, in addition to the oral and respiratory route. Furthermore, the reported altered sense of smell (anosmia) and taste (dysgeusia) in patients infected with COVID-19 may be explained by the presence of the ACE-2 receptor on tongue and nasal epithelial cells that might help mediate neurotropic or neurovirulent mechanisms to modulate taste and smell pathways.2 Because COVID-19 may be more easily detected in saliva than swabs from the nasopharynx,3 the oral cavity is a critical site for the study and prevention of COVID-19 infection. The ACE2 receptor is one target being explored for therapeutics.4
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