Stimulation of Ebola virus production from persistent infection through activation of the Ras/MAPK pathway.
Human infections with Ebola virus (EBOV) result in a deadly viral disease known as Ebola hemorrhagic fever. Up to 90% of infected patients die, and there is no available treatment or vaccine. The sporadic human outbreaks are believed to result when EBOV "jumps" from an infected animal to a person and is subsequently transmitted between persons by direct contact with infected blood or body fluids. This study was undertaken to investigate the mechanism by which EBOV can persistently infect and then escape from model cell and animal reservoir systems. We report a model system in which infection of mouse and bat cell lines with EBOV leads to persistence, which can be broken with low levels of lipopolysaccharide or phorbol-12-myristate-13-acetate (PMA). This reactivation depends on the Ras/MAPK pathway through inhibition of RNA-dependent protein kinase and eukaryotic initiation factor 2alpha phosphorylation and occurs at the level of protein synthesis. EBOV also can be evoked from mice 7 days after infection by PMA treatment, indicating that a similar mechanism occurs in vivo. Our findings suggest that EBOV may persist in nature through subclinical infection of a reservoir species, such as bats, and that appropriate physiological stimulation may result in increased replication and transmission to new hosts. Identification of a presumptive mechanism responsible for EBOV emergence from its reservoir underscores the "hit-and-run" nature of the initiation of human and/or nonhuman primate EBOV outbreaks and may provide insight into possible countermeasures to interfere with transmission.
Strong
James E
JE
Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB,Canada R3E 3R2. jim_strong@phac-aspc.gc.ca
Wong
Gary
G
Jones
Shane E
SE
Grolla
Allen
A
Theriault
Steven
S
Kobinger
Gary P
GP
Feldmann
Heinz
H
D000818:Animals; D002461:Cell Line, Transformed; D002685:Chiroptera; D004305:Dose-Response Relationship, Drug; D029043:Ebolavirus / Q000187:drug effects / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism; D005260:Female; D049452:Green Fluorescent Proteins / Q000378:metabolism; D019142:Hemorrhagic Fever, Ebola / Q000201:enzymology* / Q000821:virology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008099:Liver / Q000821:virology; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000821:virology; D051379:Mice; D008807:Mice, Inbred BALB C; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D041681:NIH 3T3 Cells; D010766:Phosphorylation / Q000187:drug effects; D013154:Spleen / Q000821:virology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D018631:ras Proteins / Q000378:metabolism*
D015852:Eukaryotic Initiation Factor-2; D008070:Lipopolysaccharides; D049452:Green Fluorescent Proteins; D020928:Mitogen-Activated Protein Kinases; D018631:ras Proteins; D013755:Tetradecanoylphorbol Acetate