Cholesterol-rich lipid rafts mediate endocytosis as a common pathway for respiratory syncytial virus entry into different host cells.

The entry of respiratory syncytial virus (RSV) into host cells is a multifaceted process involving viral adsorption, interaction of viral glycoproteins with cellular receptors, and utilization of various invasion pathways. Despite these complexities, our understanding of potential common pathways facilitating RSV entry remains limited. In this study, we demonstrate that endocytosis via cholesterol-rich lipid rafts is a common mechanism utilized by various RSV genotypes in different cell types. Specifically, RSV strains A2, B18537, and the currently epidemic ON1 strains all employ this mechanism to gain entry into human cell lines, including HEp-2, A549, and primary human bronchial epithelial cells. Cellular receptors binding to viral fusion glycoprotein were recruited to cholesterol-rich lipid rafts, leading to actin rearrangement and endosome formation, which facilitated viral entry. Furthermore, reducing cholesterol levels using methyl-β-cyclodextrin, simvastatin, or terbinafine inhibited RSV infection. Notably, combining simvastatin with an RSV fusion protein inhibitor (AK0529) resulted in enhanced antiviral effects both in vitro and in vivo. These findings expand our understanding of viral-host interaction and provide a novel therapeutic strategy for treating RSV infection.IMPORTANCERespiratory syncytial virus (RSV) is an important human pathogen that causes severe bronchiolitis and pneumonia in infants and young children. RSV entry host cells involve generally different invasion pathways and are multistep processes. However, our understanding of the associated common pathways for viral entry remains limited. Our study uncovers a pivotal role for cholesterol-rich lipid rafts in facilitating RSV entry across diverse host cells, a finding that advances our understanding of viral-host interactions and paves the way for novel antiviral strategies. By meticulously examining various RSV genotypes, we revealed shared mechanisms underlying viral entry, highlighting the significance of cholesterol regulation and its impact on infection inhibition. Our findings also demonstrate enhanced antiviral efficacy through a combined approach targeting both viral entry and cholesterol metabolism.