Scientists develop appropriate human cell line for anti-SARS-CoV-2 drug screening

In an article lately revealed within the journal Viruses, scientists have described the event of an acceptable human cell line for high-throughput screening of antiviral medicine concentrating on extreme acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Study: A Newly Engineered A549 Cell Line Expressing ACE2 and TMPRSS2 Is Highly Permissive to SARS-CoV-2, Including the Delta and Omicron Variants. Image Credit: CROCOTHERY/Shutterstock
Examine: A Newly Engineered A549 Cell Line Expressing ACE2 and TMPRSS2 Is Highly Permissive to SARS-CoV-2, Including the Delta and Omicron Variants. Picture Credit score: CROCOTHERY/Shutterstock

They scientists engineered human lung carcinoma cell line A549 to precise excessive ranges of angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2), two important host proteins required for viral entry.  


The coronavirus illness 2019 (COVID-19) pandemic brought on by SARS-CoV-2 has put an immense burden on the worldwide healthcare system, with greater than 539 million confirmed COVID-19 instances and over 6.3 million deaths worldwide. With the development of the pandemic, many viral variants with novel mutational landscapes have emerged globally. A few of them have been designated because the variants of concern (VOCs) due to considerably improved transmissibility, infectivity, virulence, and immune evasion. Given the rising menace of the pandemic on world public well being, identification and growth of SARS-CoV-2 particular antiviral medicine are urgently wanted.

Within the present examine, the scientists have described the event of a modified A549 cell line that reveals a strong expression of ACE2 and TMPRSS2 and excessive susceptibility to SARS-CoV-2 an infection. ACE2 and TMPRSS2 are important to host proteins which might be required for SARS-CoV-2 entry into host cells.  

Modification of A549 cell line     

The modification of A549 cell line was accomplished by transducing the cells with human ACE2-expressing lentivirus, adopted by puromycin-based choice of clones. Afterward, chosen clones had been transduced with TMPRSS2-expressing lentivirus.

Greater than 50 clones had been chosen. Of which, one clone confirmed strong ACE2 and TMPRSS2 expression and a excessive SARS-CoV-2 an infection fee (60%). The an infection fee within the modified cell line is much like that within the Vero E6 cell line, which is a well-established and extensively used cell line for characterizing SARS-CoV-2 an infection.

Single-cell sorting of those clones was carried out to generate single-cell-derived subclones. Susceptibility of those subclones (modified cells) to viral an infection was decided by infecting them with wildtype SARS-CoV-2 and its variants delta and omicron. Total, the modified cells confirmed excessive susceptibility to an infection by all examined viral variants. The an infection fee of the modified cells was increased than a commercially out there human ACE2- and TMPRSS2-expressing A549 cell line.   

Characterization of modified A549 cell line

Reverse transcription-polymerase chain response (RT-PCR) and movement cytometry had been carried out to find out the mRNA expressions of ACE2 and TMPRSS2 and cell floor expression of ACE2, respectively.

The findings revealed that the modified cells specific considerably increased ranges of each ACE2 and TMPRSS2 than the commercially out there ACE2- and TMPRSS2-expressing A549 cells. Furthermore, the modified cells confirmed increased infectivity for SARS-CoV-2 containing D614G mutation in comparison with the wild-type virus. The D614G is understood to intervene with ACE2 receptor binding and viral entry.

Software of modified A549 cells

The utility of modified A549 cells as a screening platform for antiviral medicine was examined within the examine. Particularly, SARS-CoV-2-infected modified cells had been used to check the antiviral efficacy of 9 antiviral medicine (repurposed anti-COVID 19 medicine Nirmatrelvir, EIDD-1931, remdesivir; anti-HIV drug Nelfinavir; and widely-used antiviral drug candidates camostat mesylate, naphthofluorescein, E64d, and decanoyl-RVKR-CMK).     

The dose-response evaluation revealed that each one repurposed medicine in addition to the anti-HIV drug strongly inhibit SARS-CoV-2 an infection in modified cells. Amongst drug candidates, solely camostat mesylate considerably inhibited the viral an infection. These observations point out that the modified cells can be utilized for high-throughput screening of antiviral medicine.

Moreover, the modified cells had been used to check the antiviral efficacy of a panel of medicine in opposition to delta and omicron infections. All examined antiviral medicine (EIDD-1931, remdesivir, nirmatrelvir, and nelfinavir) confirmed dose-dependent inhibition of an infection brought on by wildtype SARS-CoV-2 and delta and omicron variants. Within the modified cells, the omicron variant confirmed increased sensitivity to the drug therapy in comparison with wildtype SARS-CoV-2 and the delta variant.

Examine significance

A human cell mannequin appropriate for SARS-CoV-2 an infection has been developed within the examine. Lentiviral transduction methodology has been used to stably and robustly specific human ACE2 and TMPRSS2 in A549 cells. As prompt by the scientists, these modified A549 cells might be probably used to review rising SARS-CoV-2 variants and display antiviral medicine.

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