HS-AFM and SERS Analysis of Murine Norovirus Infection: Involvement of the Lipid Rafts
Résumé
Studies on human norovirus are severely hampered by the absence of a cell
culture system until the discovery of murine norovirus (MNV). The cell membrane
domains called lipid rafts have been defined as a port of entry for viruses. This
study is conducted to investigate murine norovirus binding on the mouse leukemic
monocyte macrophage cell line. Lipid raft related structures are extracted from cells
by detergent treatment resulting detergent-resistant membrane (DRMs) domains. The
real-time polymerase chain reaction technique is performed to detect the viral genome,
thereby the MNV binding on the DRMs. The interactions between MNV and DRMs
are investigated by high-speed atomic force microscopy (HS-AFM) combined with
surface-enhanced Raman spectroscopy (SERS). The inoculation of the virus onto
cells results in the aggregations of detergent-resistant membrane domains significantly.
The characteristic Raman band of MNV is found in inoculated samples. To be sure
that these results are originated from specific interactions between DRM and MNV,
methyl-β-cyclo-dextrin (MβCD) is applied to disrupt lipid rafts. The MNV binding
on DRMs is precluded by the MβCD treatment. The cholesterols chains are defined as
a key factor in the interactions between norovirus and DRMs. The authors conclude
that the MNV binding involves the presence of DRMs and cholesterol dependent.