Dual inhibition of intercellular adhesion molecule-1 and nucleolin reduces RSV infection efficiency in human respiratory organoids.

Respiratory syncytial virus (RSV) is one of the major causes of lower respiratory tract infections, particularly in infants and older adults. However, the host factors mediating infection remain poorly defined. It has been suggested that four host surface proteins, namely intercellular adhesion molecule-1 (ICAM-1), epidermal growth factor receptor (EGFR), nucleolin (NCL), and insulin-like growth factor 1 receptor (IGF1R), may interact with the RSV fusion (F) protein. To investigate these roles under physiologically relevant conditions, we employed human induced pluripotent stem cell (iPSC)-derived respiratory organoids as a model for RSV infection. In this model, ICAM-1 and EGFR were genetically depleted using the CRISPR-Cas9 genome editing technique, while NCL and IGF1R were inhibited with neutralizing antibodies. Suppression of ICAM-1 or NCL significantly reduced RSV nucleoprotein gene expression, whereas inhibition of EGFR or IGF1R had no observable effect on viral gene expression. Notably, simultaneous suppression of ICAM-1 and NCL resulted in a more substantial reduction in infectious viral titers and RSV F protein expression than inhibition of either protein alone. Our results suggest that both ICAM-1 and NCL may play important roles during RSV infection in human iPSC-derived respiratory organoids.