High expression of SARS-CoV2 viral entry-related proteins in human limbal stem cells

Document Type

Journal Article

Publication Title

Ocular Surface

Volume

23

First Page

197

Last Page

200

PubMed ID

34653711

Publisher

Elsevier

School

School of Medical and Health Sciences

RAS ID

42680

Funders

National Institutes of Health grants 1K99EY031741, 1R01EY025794, R24EY028767 , Schepens Core grant P30EY003790, grant 2T32EB016652-06

Comments

Sasamoto, Y., Lee, C. A., Yoshihara, M., Martin, G., Ksander, B. R., Frank, M. H., & Frank, N. Y. (2022). High expression of SARS-CoV2 viral entry-related proteins in human limbal stem cells. The ocular surface, 23, 197-200.

https://doi.org/10.1016/j.jtos.2021.10.002

Abstract

Purpose:

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV2). While the ocular surface is considered one of the major SARS-CoV2 transmission routes, the specific cellular tropism of SARS-CoV2 is not fully understood. In the current study, we evaluated the expression and regulation of two SARS-CoV2 viral entry proteins, TMPRSS2 and ACE2, in human ocular epithelial cells and stem cells.

Methods:

TMPRSS2 and ACE2 expression in ABCB5-positive limbal stem cells (LSCs) were assessed by RNAseq, flow cytometry and immunohistochemistry. PAX6, TMPRSS2, and ACE2 mRNA expression values were obtained from the GSE135455 and DRA002960 RNA-seq datasets. siRNA-mediated PAX6 knockdown (KD) was performed in limbal and conjunctival epithelial cells. TMPRSS2 and ACE2 expression in the PAX6 KD cells was analyzed by qRT-PCR and Western blot.

Results:

We found that ABCB5-positive LSCs express high levels of TMPRSS2 and ACE2 compared to ABCB5-negative limbal epithelial cells. Mechanistically, gene knockout and overexpression models revealed that the eye transcription factor PAX6 negatively regulates TMPRSS2 expression. Therefore, low levels of PAX6 in ABCB5-positive LSCs promote TMPRSS2 expression, and high levels of TMPRSS2 and ACE2 expression by LSCs indicate enhanced susceptibility to SARS-CoV2 infection in this stem cell population.

Conclusions:

Our study points to a need for COVID-19 testing of LSCs derived from donor corneas before transplantation to patients with limbal stem cell deficiency. Furthermore, our findings suggest that expandable human ABCB5+ LSC cultures might represent a relevant novel model system for studying cellular SARS-CoV2 viral entry mechanisms and evaluating related targeting strategies.

DOI

10.1016/j.jtos.2021.10.002

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