title: Human SCARB2-mediated entry and endocytosis of EV71.
abstract: Enterovirus (EV) 71 infection is known to cause hand-foot-and-mouth disease (HFMD) and in severe cases, induces neurological disorders culminating in fatality. An outbreak of EV71 in South East Asia in 1997 affected over 120,000 people and caused neurological disorders in a few individuals. The control of EV71 infection through public health interventions remains minimal and treatments are only symptomatic. Recently, human scavenger receptor class B, member 2 (SCARB2) has been reported to be a cellular receptor of EV71. We expressed human SCARB2 gene in NIH3T3 cells (3T3-SCARB2) to study the mechanisms of EV71 entry and infection. We demonstrated that human SCARB2 serves as a cellular receptor for EV71 entry. Disruption of expression of SCARB2 using siRNAs can interfere EV71 infection and subsequent inhibit the expression of viral capsid proteins in RD and 3T3-SCARB2 but not Vero cells. SiRNAs specific to clathrin or dynamin or chemical inhibitor of clathrin-mediated endocytosis were all capable of interfering with the entry of EV71 into 3T3-SCARB2 cells. On the other hand, caveolin specific siRNA or inhibitors of caveolae-mediated endocytosis had no effect, confirming that only clathrin-mediated pathway was involved in EV71 infection. Endocytosis of EV71 was also found to be pH-dependent requiring endosomal acidification and also required intact membrane cholesterol. In summary, the mechanism of EV71 entry through SCARB2 as the receptor for attachment, and its cellular entry is through a clathrin-mediated and pH-dependent endocytic pathway. This study on the receptor and endocytic mechanisms of EV71 infection is useful for the development of effective medications and prophylactic treatment against the enterovirus.
authors.affiliation: National Institutes of Infectious Disease and Vaccinology, National Health Research Institutes, Taiwan, Republic of China.
authors.forename: Yi-Wen
authors.initials: YW
authors.lastname: Lin
authors.forename: Hsiang-Yin
authors.initials: HY
authors.lastname: Lin
authors.forename: Yueh-Liang
authors.initials: YL
authors.lastname: Tsou
authors.forename: Ebenezer
authors.initials: E
authors.lastname: Chitra
authors.forename: Kuang-Nan
authors.initials: KN
authors.lastname: Hsiao
authors.forename: Hsiao-Yun
authors.initials: HY
authors.lastname: Shao
authors.forename: Chia-Chyi
authors.initials: CC
authors.lastname: Liu
authors.forename: Charles
authors.initials: C
authors.lastname: Sia
authors.forename: Pele
authors.initials: P
authors.lastname: Chong
authors.forename: Yen-Hung
authors.initials: YH
authors.lastname: Chow
mesh_terms: D000818:Animals; D015153:Blotting, Western; D036022:Capsid Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000737:chemistry; D002522:Chlorocebus aethiops; D002784:Cholesterol / Q000378:metabolism; D002966:Clathrin / Q000235:genetics / Q000378:metabolism; D034281:Dynamins / Q000235:genetics / Q000378:metabolism; D004705:Endocytosis; D011992:Endosomes / Q000737:chemistry; D029821:Enterovirus A, Human / Q000254:growth & development / Q000378:metabolism*; D004769:Enterovirus Infections / Q000821:virology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D047468:Immunoprecipitation; D051907:Lysosomal Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D041681:NIH 3T3 Cells; D011485:Protein Binding; D034622:RNA Interference; D051116:Receptors, Scavenger / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D014709:Vero Cells; D053586:Virus Internalization
chemical_list: D036022:Capsid Proteins; D002966:Clathrin; D051907:Lysosomal Membrane Proteins; D051116:Receptors, Scavenger; C074299:SCARB2 protein, human; D002784:Cholesterol; D034281:Dynamins