| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2010: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2009: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
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| Research Abstract |
Enterovirus 71 (EV71) is a major causative agent of hand, foot, and mouth disease (HFMD), a common febrile disease occurring mainly in young children. In this study, I identified human P-selectin glycoprotein ligand-1 (PSGL-1), a sialomucin membrane protein expressed on leukocytes that plays a critical role in early stages of inflammation, as a functional receptor for EV71. The N terminal region of PSGL-1 bound specifically to EV71. The stable PSGL-1 expression conferred EV71 entry, replication, and development of cytopathic effect to nonsusceptible mouse L929 cells. Five out of eight EV71 strains bound to soluble PSGL-1 and utilized intact PSGL-1 as the primary receptor for infection of Jurkat T cells. Three other EV71 strains did not utilize PSGL-1, suggesting the presence of strain-specific replication of EV71 in leukocytes. EV71 replicated in nonleukocyte cell lines in a PSGL-1-independent manner, indicating the presence of alternative receptor (s) for EV71.
To elucidate the molecular basis of the PSGL-1-EV71 interaction, we generated a series of PSGL-1 mutants and identified the post-translational modifications that are critical for binding of PSGL-1 to EV71. Site-directed mutagenesis at one or more potential tyrosine sulfation sites in the N-terminal region of PSGL-1 significantly impaired PSGL-1 binding to EV71. Furthermore, an inhibitor of sulfation, sodium chlorate, blocked the PSGL-1-EV71 interaction and inhibited PSGL-1-mediated viral replication of EV71 in Jurkat T cells in a dose-dependent manner. Thus, the results presented in this study reveal that tyrosine sulfation, but not O-glycosylation, in the N-terminal region of PSGL-1 may facilitate virus entry and replication of EV71 in leukocytes.
Thus, the identification of PSGL-1 as a receptor for EV71 sheds new light on a role for PSGL-1-positive leukocytes in cell tropism and pathogenesis during the course of HFMD and a variety of other EV71 -mediated diseases.
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