Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to have a significant impact on global public health. Multiple mechanisms for SARS-CoV-2 cell entry have been described; however, the role of transferrin receptor 1 (TfR1) in SARS-CoV-2 infection has received little attention. We used ferristatin II to induce the degradation of TfR1 on the surface of Vero cells and to study the consequences of such treatment on the viability of the cells and the replication of SARS-CoV-2. We demonstrated that ferristatin II is non-toxic for Vero cells in concentrations up to 400 µM. According to confocal microscopy data, the distribution of the labeled transferrin and receptor-binding domain (RBD) of Spike protein is significantly affected by the 18h pretreatment with 100 µM ferristatin II in culture medium. The uptake of RBD protein is nearly fully inhibited by ferristatin II treatment, although this protein remains bound on the cell surface. The findings were well confirmed by the significant inhibition of the SARS-CoV-2 infection of Vero cells by ferristatin II with IC50 values of 27 µM (for Wuhan D614G virus) and 40 µM (for Delta virus). A significant reduction in the infectious titer of the Omicron SARS-CoV-2 variant was noted at a ferristatin II concentration as low as 6.25 µM. We hypothesize that ferristatin II blocks the TfR1-mediated SARS-CoV-2 host cell entry; however, further studies are needed to elucidate the full mechanisms of this virus inhibition, including the effect of ferristatin II on other SARS-CoV-2 receptors, such as ACE2, Neuropilin-1 and CD147. The inhibition of viral entry by targeting the receptor on the host cells, rather than the viral mutation-prone protein, is a promising COVID-19 therapeutic strategy.
Highlights
The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to pose a significant socioeconomic burden to the world’s population
The detection of viral antigen in cell-base ELISA found that the IC50 values for ferristatin II were 26.5 and 40.4 μM for the Wuhan D614G and Delta viruses, respectively (Figure 2A)
The quantification of the virus titers in culture media confirmed that the release of the virus from the infected cells into the culture medium was inhibited by ferristatin II, starting from 25 μM concentration, and IC50 values calculated from the reduction in TCID50 titers were 24.0 and 25.2 μM for the Wuhan D614G and Delta viruses, respectively
Summary
The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to pose a significant socioeconomic burden to the world’s population. Two proteolytic cleavage steps are required for effective SARS-CoV-2 entry into cells after the engagement of a host cell receptor by a viral spike (S) protein. Aside fromthe well-studied SARS-CoV-2 host cell entry targets, there is evidence that transferrin receptor 1 (TfR1) can be an alternative co-receptor for SARS-CoV-2 entry [12]. TfR1, a 95 kDahomodimeric type II membrane glycoprotein, is abundantly expressed on the plasma membrane of most human cells and mediates the entry of transferrin (Tf) into cells for the delivery of iron [13]. Targeting the TfR1mediated viral entry pathway represents a promising therapeutic strategy for SARS-CoV-2 infection. Screening studies identified two small-size compounds (NCI11079 and NCI306711) that had a significant inhibitory effect on Tf-mediated iron uptake by HeLa cells
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
