Cholesterol-rich
lipid rafts have been shown to play important roles in the life cycle of various non-enveloped and enveloped viruses. Deletion of
cholesterol from
lipid rafts could influence different steps of viral replication cycle including entry,
infection, assembly and release. Caprine
parainfluenza virus type3 (CPIV3) is a newly identified member of Paramyxoviridae family. CPIV3 is highly prevalence and threatened the goat industry in China. The
infection mechanism of CPIV3 is under exploring and still not fully understood, the roles of
cholesterol and
lipid rafts for CPIV3
infection remains unclear. In this study, we investigated the association of
cholesterol and
lipid rafts with CPIV3 during the different viral replication stages (binding, entry and
infection) in two cells [MDBK and goat bronchial epithelial (GBE) cells]. Methyl-β-
cyclodextrin (MβCD) was used to deplete
cholesterol from cell and viral membranes. The results showed that MβCD treatment significantly inhibited CPIV3 entry and
infection in these two cells with a dose-dependent manner, but didn't impair the binding of CPIV3. Addition of exogenous
cholesterol to the cells after MβCD treatment restored the
viral infection. In addition, treatment of MβCD only before virus-entry showed inhibitory effect in MDBK cells. Depletion of
cholesterol from virion envelop also decreased the entry and
infection of CPIV3 in the two cells. Furthermore,
lipid rafts isolation test indicated that
viral proteins (HN and N) co-localized with
lipid rafts during
infection in MDBK and GBE cells.
Viral N protein co-localized with
caveolin-1 (the marker of
lipid rafts) in these two cells both at the entry and
infection steps, as detected by con-focal
laser scanning microscopy test. In conclusion, the results presented here demonstrated that
cholesterol rich
lipid rafts play an important role in CPIV3 life cycle. The findings give new insights on understanding of the mechanism of CPIV3
infection and provide a new anti-CPIV3 strategy.