Ebolavirus Is Internalized into Host Cells via Macropinocytosis in a Viral Glycoprotein-Dependent Manner

• Published in: PLoS pathogens Vol. 6; no. 9; p. e1001121
• Main Authors: Nanbo, Asuka, Imai, Masaki, Watanabe, Shinji, Noda, Takeshi, Takahashi, Kei, Neumann, Gabriele, Halfmann, Peter, Kawaoka, Yoshihiro
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01.09.2010; Public Library of Science (PLoS)
• Subjects: Animals; Blotting, Western; Caveolae - metabolism; Caveolae - virology; Cell Biology; Cells, Cultured; Cercopithecus aethiops; Clathrin - metabolism; Ebola virus; Ebolavirus - physiology; Endocytosis - physiology; Gene expression; Genetic aspects; Hemorrhagic Fever, Ebola - metabolism; Hemorrhagic Fever, Ebola - virology; Humans; Infections; Infectious disease incubation period; Infectious Diseases/Viral Infections; Influenza; Kinases; Lasers; Microscopy, Fluorescence; Mortality; Physiological aspects; Pinocytosis; Pinocytosis - physiology; Plasma; Primates; Proteins; rab GTP-Binding Proteins - genetics; rab GTP-Binding Proteins - metabolism; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - genetics; Signal Transduction; Sorting Nexins - genetics; Sorting Nexins - metabolism; Studies; Vero Cells; Vesicular stomatitis virus; Vesiculovirus; Viral Envelope Proteins - genetics; Viral Envelope Proteins - metabolism; Virion - genetics; Virology/Host Invasion and Cell Entry; Virus Internalization; Virus Replication; Japan
• ISSN: 1553-7374; 1553-7366; 1553-7374
• DOI: 10.1371/journal.ppat.1001121

Ebolavirus (EBOV) is an enveloped, single-stranded, negative-sense RNA virus that causes severe hemorrhagic fever with mortality rates of up to 90% in humans and nonhuman primates. Previous studies suggest roles for clathrin- or caveolae-mediated endocytosis in EBOV entry; however, ebolavirus virions are long, filamentous particles that are larger than the plasma membrane invaginations that characterize clathrin- or caveolae-mediated endocytosis. The mechanism of EBOV entry remains, therefore, poorly understood. To better understand Ebolavirus entry, we carried out internalization studies with fluorescently labeled, biologically contained Ebolavirus and Ebolavirus-like particles (Ebola VLPs), both of which resemble authentic Ebolavirus in their morphology. We examined the mechanism of Ebolavirus internalization by real-time analysis of these fluorescently labeled Ebolavirus particles and found that their internalization was independent of clathrin- or caveolae-mediated endocytosis, but that they co-localized with sorting nexin (SNX) 5, a marker of macropinocytosis-specific endosomes (macropinosomes). Moreover, the internalization of Ebolavirus virions accelerated the uptake of a macropinocytosis-specific cargo, was associated with plasma membrane ruffling, and was dependent on cellular GTPases and kinases involved in macropinocytosis. A pseudotyped vesicular stomatitis virus possessing the Ebolavirus glycoprotein (GP) also co-localized with SNX5 and its internalization and infectivity were affected by macropinocytosis inhibitors. Taken together, our data suggest that Ebolavirus is internalized into cells by stimulating macropinocytosis in a GP-dependent manner. These findings provide new insights into the lifecycle of Ebolavirus and may aid in the development of therapeutics for Ebolavirus infection.