The ubiquitin proteasome system plays a role in venezuelan equine encephalitis virus infection.
Many viruses have been implicated in utilizing or modulating the Ubiquitin Proteasome System (UPS) to enhance viral multiplication and/or to sustain a persistent infection. The mosquito-borne Venezuelan equine encephalitis virus (VEEV) belongs to the Togaviridae family and is an important biodefense pathogen and select agent. There are currently no approved vaccines or therapies for VEEV infections; therefore, it is imperative to identify novel targets for therapeutic development. We hypothesized that a functional UPS is required for efficient VEEV multiplication. We have shown that at non-toxic concentrations Bortezomib, a FDA-approved inhibitor of the proteasome, proved to be a potent inhibitor of VEEV multiplication in the human astrocytoma cell line U87MG. Bortezomib inhibited the virulent Trinidad donkey (TrD) strain and the attenuated TC-83 strain of VEEV. Additional studies with virulent strains of Eastern equine encephalitis virus (EEEV) and Western equine encephalitis virus (WEEV) demonstrated that Bortezomib is a broad spectrum inhibitor of the New World alphaviruses. Time-of-addition assays showed that Bortezomib was an effective inhibitor of viral multiplication even when the drug was introduced many hours post exposure to the virus. Mass spectrometry analyses indicated that the VEEV capsid protein is ubiquitinated in infected cells, which was validated by confocal microscopy and immunoprecipitation assays. Subsequent studies revealed that capsid is ubiquitinated on K48 during early stages of infection which was affected by Bortezomib treatment. This study will aid future investigations in identifying host proteins as potential broad spectrum therapeutic targets for treating alphavirus infections.
National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, United States of America.
Moushimi
M
Amaya
National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, United States of America.
Forrest
F
Keck
United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America.
Michael
M
Lindquist
National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, United States of America.
Kelsey
K
Voss
National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, United States of America.
Lauren
L
Scavone
National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, United States of America.
Kylene
K
Kehn-Hall
Leidos Health Life Sciences, Frederick, Maryland, United States of America.
Brian
B
Roberts
National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, United States of America.
Charles
C
Bailey
United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America.
Connie
C
Schmaljohn
National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, United States of America.
Aarthi
A
Narayanan
D000818:Animals; D015153:Blotting, Western; D000069286:Bortezomib / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D004666:Encephalitis Virus, Venezuelan Equine / Q000187:drug effects / Q000472:pathogenicity*; D004685:Encephalomyelitis, Venezuelan Equine / Q000378:metabolism*; D006168:Guinea Pigs; D047468:Immunoprecipitation; D017404:In Situ Hybridization, Fluorescence; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D053719:Tandem Mass Spectrometry; D025801:Ubiquitin / Q000378:metabolism*
D025801:Ubiquitin; D000069286:Bortezomib; D046988:Proteasome Endopeptidase Complex