Direct derivation of human alveolospheres for SARS-CoV-2 infection modeling and drug screening

Cell Rep. 2021 Jun 8;35(10):109218. doi: 10.1016/j.celrep.2021.109218. Epub 2021 May 19.


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.

Keywords: COVID-19; alveolosphere; drug screening; lung; organoid; stem cell niche.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alveolar Epithelial Cells / drug effects*
  • Alveolar Epithelial Cells / metabolism
  • Alveolar Epithelial Cells / virology
  • Angiotensin-Converting Enzyme 2 / metabolism
  • Antiviral Agents / pharmacology*
  • COVID-19 / drug therapy*
  • COVID-19 / metabolism
  • COVID-19 / virology
  • Cells, Cultured
  • Drug Evaluation, Preclinical*
  • Host-Pathogen Interactions
  • Humans
  • Proto-Oncogene Proteins c-akt / metabolism
  • SARS-CoV-2 / drug effects*
  • SARS-CoV-2 / growth & development
  • SARS-CoV-2 / pathogenicity
  • Spheroids, Cellular
  • Time Factors
  • Virus Replication / drug effects
  • Wnt Signaling Pathway


  • Antiviral Agents
  • Proto-Oncogene Proteins c-akt
  • ACE2 protein, human
  • Angiotensin-Converting Enzyme 2

Supplementary concepts

  • COVID-19 drug treatment