The role of lipid rafts in cell entry of human metapneumovirus.

Human metapneumovirus (hMPV) is a crucial pathogen in children. A cell entry is the first step for infection. Our previous study indicated that there was an endocytosis pathway for hMPV cell entry. Lipid raft is a specific structure at the cell surface and it has been demonstrated to play an important role in endocytosis process of many viruses. In this study, we investigated whether and how lipid raft can take part in the hMPV entry. The confocal microscope was used to detect colocalization of hMPV and lipid raft marker. We demonstrated that colocalizations were increased along with the viral infection and hMPV particles transferred to the perinuclear region with lipid raft. When specific lipid raft inhibitors: methyl-β cyclodextrin and nystatin were used, hMPV cell entry was inhibited and viral titer decreased dramatically. With the replenishment of exogenous cholesterol, hMPV recovered quickly. These data suggest that lipid raft plays an important role in hMPV endocytosis and maybe one of the pathways for hMPV cell entry.