ABSTRACT
It has been reported that many receptors and proteases are required for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Although angiotensin-converting enzyme 2 (ACE2) is the most important of these receptors, little is known about the contribution of other genes. In this study, we examined the roles of neuropilin-1, basigin, transmembrane serine proteases (TMPRSSs), and cathepsins (CTSs) in SARS-CoV-2 infection using the CRISPR interference system and ACE2-expressing human induced pluripotent stem (iPS) cells. Double knockdown of TMPRSS2 and cathepsin B (CTSB) reduced the viral load to 0.036% ± 0.021%. Consistently, the combination of the CTPB inhibitor CA-074 methyl ester and the TMPRSS2 inhibitor camostat reduced the viral load to 0.0078% ± 0.0057%. This result was confirmed using four SARS-CoV-2 variants (B.1.3, B.1.1.7, B.1.351, and B.1.1.248). The simultaneous use of these two drugs reduced viral load to less than 0.01% in both female and male iPS cells. These findings suggest that compounds targeting TMPRSS2 and CTSB exhibit highly efficient antiviral effects independent of gender and SARS-CoV-2 variant.
ABSTRACT
Experimental cell models are indispensable for clarifying the pathophysiology of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and for developing therapeutic agents. To recapitulate the symptoms and drug response of COVID-19 patients in vitro, SARS-CoV-2 studies using physiologically relevant human embryonic stem (ES)/induced pluripotent stem (iPS) cell-derived somatic cells and organoids are ongoing. These cells and organoids have been used to show that SARS-CoV-2 can infect and damage various organs including the lung, heart, brain, intestinal tract, kidney, and pancreas. They are also being used to develop COVID-19 therapeutic agents, including evaluation of their antiviral efficacy and safety. The relationship between COVID-19 aggravation and human genetic backgrounds has been investigated using genetically modified ES/iPS cells and patient-derived iPS cells. This review summarizes the latest results and issues of SARS-CoV-2 research using human ES/iPS cell-derived somatic cells and organoids.