‘Mini-lungs’ reveal early stages of SARS-CoV-2 infection

‘Mini-lungs’ grown from tissue donated to Cambridge hospitals has provided a team of scientists from South Korea and the UK with important insights into how COVID-19 damages the lungs. Writing in the journal Cell Stem Cell, the researchers detail the mechanisms underlying SARS-CoV-2 infection and the early innate immune response in the lungs.

ar cells began to disintegrate, leading to cell death and damage to the lung tissue.

Although the researchers observed changes to the lung cells within three days of infection, clinical symptoms of COVID-19 rarely occur so quickly and can sometimes take more than ten days after exposure to appear. The team say there are several possible reasons for this. It may take several days from the virus first infiltrating the upper respiratory tract to it reaching the alveoli. It may also require a substantial proportion of alveolar cells to be infected or for further interactions with immune cells resulting in inflammation before a patient displays symptoms.

“Based on our model we can tackle many unanswered key questions, such as understanding genetic susceptibility to SARS-CoV-2, assessing relative infectivity of viral mutants, and revealing the damage processes of the virus in human alveolar cells,” said Dr Young Seok Ju, co-senior author, and an Associate Professor at Korea Advanced Institute of Science and Technology. “Most importantly, it provides the opportunity to develop and screen potential therapeutic agents against SARS-CoV-2 infection.”

“We hope to use our technique to grow these 3D models from cells of patients who are particularly vulnerable to infection, such as the elderly or people with diseased lungs, and find out what happens to their tissue,” added Dr Lee.

The research was a collaboration involving scientists from the University of Cambridge, UK, and the Korea Advanced Institute Science and Technology (KAIST), Korea National Institute of Health, Institute for Basic Science (IBS), Seoul National University Hospital and GENOME INSIGHT Inc. in South Korea.

Reference
Jeonghwan Youk et al. Three-dimensional human alveolar stem cell culture models reveal infection response to SARS-CoV-2. Cell Stem Cell; 21 Oct 2020; DOI: 10.1016/j.stem.2020.10.004

Funding
The research was supported by: the National Research Foundation of Korea; Research of Korea Centers for Disease Control and Prevention; Ministry of Science and ICT of Korea; Ministry of Health & Welfare, Republic of Korea; Seoul National University College of Medicine Research Foundation; European Research Council; Wellcome; the Royal Society; Biotechnology and Biological Sciences Research; Suh Kyungbae Foundation; and the Human Frontier Science Program.

Image caption
Representative image of three-dimensional human lung alveolar organoid showing alveolar stem cell marker, HTII-280 (red) and SARS-CoV-2 entry protein, ACE2 (green). (Credit: Jeonghwan Youk, Taewoo Kim, and Seon Pyo Hong)