title: Critical role of lipid rafts in virus entry and activation of phosphoinositide 3' kinase/Akt signaling during early stages of Japanese encephalitis virus infection in neural stem/progenitor cells.
abstract: Japanese encephalitis virus (JEV), the leading cause of acute encephalitis in South-East Asia is a neurotropic virus infecting various CNS cell types. Most Flaviviruses including JEV get internalised into cells by receptor-mediated endocytosis, which involve clathrin and membrane cholesterol. The cholesterol-enriched membrane microdomains referred to as lipid rafts act as portals for virus entry in a number of enveloped viruses, including Flavivirus. However, the precise role played by membrane lipid rafts in JEV internalisation into neural stem cells is still unknown. We have established neural stem/progenitor cells and C17.2 cell line as models of productive JEV infection. Increase in membrane fluidity and clustering of viral envelope proteins in lipid rafts was observed in early time points of infection. Localisation of non-structural proteins to rafts at later infection stages was also observed. Co-localisation of JEV glycoprotein with Cholera toxin B confirmed that JEV internalisation occurs in a lipid-raft dependent manner. Though JEV entry is raft dependent, however, there is requirement of functional clathrin during endocytosis inside the cells. Besides virus entry, the lipid rafts act as signalling platforms for Src tyrosine kinases and result in activation of phosphoinositìde 3'-kinase/Akt signalling during early JEV infection. Disruption of lipid raft formation by cholesterol depletion using Methyl β-cyclodextrin, reduced JEV RNA levels and production of infectious virus particles as well as impaired phosphoinositìde 3'-kinase/Akt signalling during initial infection. Overall, our results implicate the importance of host membrane lipid rafts in JEV entry and life cycle, besides maintaining survival of neural stem/progenitor cells during early infection.
authors: National Brain Research Centre, Manesar, Haryana, India.
authors: Sulagna
authors: S
authors: Das
authors: Swarupa
authors: S
authors: Chakraborty
authors: Anirban
authors: A
authors: Basu
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D002772:Cholera Toxin / Q000378:metabolism; D002966:Clathrin / Q000494:pharmacology; D004664:Encephalitis Virus, Japanese / Q000502:physiology*; D004705:Endocytosis / Q000502:physiology; D005454:Fluorescence Polarization / Q000379:methods; D021962:Membrane Microdomains / Q000201:enzymology* / Q000821:virology; D051379:Mice; D008807:Mice, Inbred BALB C; D009474:Neurons / Q000166:cytology / Q000201:enzymology / Q000821:virology; D051058:Oncogene Protein v-akt / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D013234:Stem Cells / Q000201:enzymology* / Q000821:virology; D014162:Transfection / Q000379:methods; D014168:Transferrin / Q000378:metabolism; D014759:Viral Envelope Proteins / Q000378:metabolism
chemical_list: D002966:Clathrin; D014168:Transferrin; D014759:Viral Envelope Proteins; D002772:Cholera Toxin; D019869:Phosphatidylinositol 3-Kinases; D051058:Oncogene Protein v-akt