Direct derivation of human alveolospheres for SARS-CoV-2 infection modeling and drug screening
Toshiki Ebisudani, Shinya Sugimoto, Kei Haga, Akifumi Mitsuishi, Reiko Takai‐Todaka, Masayuki Fujii, Kohta Toshimitsu, Junko Hamamoto, Kai Sugihara, Tomoyuki Hishida, Hisao Asamura, Koichi Fukunaga, Hiroyuki Yasuda, Kazuhiko Katayama, Toshiro Sato
Abstract
Although the main cellular target of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is thought to be alveolar cells, the absence of their tractable culture system precludes the development of a clinically relevant SARS-CoV-2 infection model. Here, we establish an efficient human alveolosphere culture method and sphere-based drug testing platform for SARS-CoV-2. Alveolospheres exhibit indolent growth in a Wnt- and R-spondin-dependent manner. Gene expression, immunofluorescence, and electron microscopy analyses reveal the presence of alveolar cells in alveolospheres. Alveolospheres express ACE2 and allow SARS-CoV-2 to propagate nearly 100,000-fold in 3 days of infection. Whereas lopinavir and nelfinavir, protease inhibitors used for the treatment of human immunodeficiency virus (HIV) infection, have a modest anti-viral effect on SARS-CoV-2, remdesivir, a nucleotide prodrug, shows an anti-viral effect at the concentration comparable with the circulating drug level. These results demonstrate the validity of the alveolosphere culture system for the development of therapeutic agents to combat SARS-CoV-2.