title: Calcium Regulation of Hemorrhagic Fever Virus Budding: Mechanistic Implications for Host-Oriented Therapeutic Intervention.
abstract: Hemorrhagic fever viruses, including the filoviruses (Ebola and Marburg) and arenaviruses (Lassa and Junín viruses), are serious human pathogens for which there are currently no FDA approved therapeutics or vaccines. Importantly, transmission of these viruses, and specifically late steps of budding, critically depend upon host cell machinery. Consequently, strategies which target these mechanisms represent potential targets for broad spectrum host oriented therapeutics. An important cellular signal implicated previously in EBOV budding is calcium. Indeed, host cell calcium signals are increasingly being recognized to play a role in steps of entry, replication, and transmission for a range of viruses, but if and how filoviruses and arenaviruses mobilize calcium and the precise stage of virus transmission regulated by calcium have not been defined. Here we demonstrate that expression of matrix proteins from both filoviruses and arenaviruses triggers an increase in host cytoplasmic Ca2+ concentration by a mechanism that requires host Orai1 channels. Furthermore, we demonstrate that Orai1 regulates both VLP and infectious filovirus and arenavirus production and spread. Notably, suppression of the protein that triggers Orai activation (Stromal Interaction Molecule 1, STIM1) and genetic inactivation or pharmacological blockade of Orai1 channels inhibits VLP and infectious virus egress. These findings are highly significant as they expand our understanding of host mechanisms that may broadly control enveloped RNA virus budding, and they establish Orai and STIM1 as novel targets for broad-spectrum host-oriented therapeutics to combat these emerging BSL-4 pathogens and potentially other enveloped RNA viruses that bud via similar mechanisms.
authors.affiliation: Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Ziying
authors.initials: Z
authors.lastname: Han
authors.affiliation: Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Madara
authors.affiliation: United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America.
authors.forename: Andrew
authors.initials: A
authors.lastname: Herbert
authors.affiliation: United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America.
authors.forename: Laura I
authors.initials: LI
authors.lastname: Prugar
authors.affiliation: Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Gordon
authors.initials: G
authors.lastname: Ruthel
authors.affiliation: Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Jianhong
authors.initials: J
authors.lastname: Lu
authors.affiliation: Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Yuliang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Wenbo
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Liu
authors.affiliation: Fox Chase Chemical Diversity Center, Inc., Doylestown, Pennsylvania, United States of America.
authors.forename: Jay E
authors.initials: JE
authors.lastname: Wrobel
authors.affiliation: Fox Chase Chemical Diversity Center, Inc., Doylestown, Pennsylvania, United States of America.
authors.forename: Allen B
authors.initials: AB
authors.lastname: Reitz
authors.affiliation: United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America.
authors.forename: John M
authors.initials: JM
authors.lastname: Dye
authors.affiliation: Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Ronald N
authors.initials: RN
authors.lastname: Harty
authors.affiliation: Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Freedman
mesh_terms: D000818:Animals; D018050:Arenavirus / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000502:physiology; D016563:Filoviridae / Q000502:physiology*; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D000071740:ORAI1 Protein; D014709:Vero Cells; D014763:Viral Matrix Proteins / Q000502:physiology; D014771:Virion / Q000502:physiology; D057074:Virus Release
chemical_list: D015220:Calcium Channels; D000071740:ORAI1 Protein; C510746:ORAI1 protein, human; C080981:VP40 protein, virus; D014763:Viral Matrix Proteins; D002118:Calcium