title: Antiviral screening identifies adenosine analogs targeting the endogenous dsRNA Leishmania RNA virus 1 (LRV1) pathogenicity factor.
abstract: The endogenous double-stranded RNA (dsRNA) virus Leishmaniavirus (LRV1) has been implicated as a pathogenicity factor for leishmaniasis in rodent models and human disease, and associated with drug-treatment failures in Leishmania braziliensis and Leishmania guyanensis infections. Thus, methods targeting LRV1 could have therapeutic benefit. Here we screened a panel of antivirals for parasite and LRV1 inhibition, focusing on nucleoside analogs to capitalize on the highly active salvage pathways of Leishmania, which are purine auxotrophs. Applying a capsid flow cytometry assay, we identified two 2'-C-methyladenosine analogs showing selective inhibition of LRV1. Treatment resulted in loss of LRV1 with first-order kinetics, as expected for random virus segregation, and elimination within six cell doublings, consistent with a measured LRV1 copy number of about 15. Viral loss was specific to antiviral nucleoside treatment and not induced by growth inhibitors, in contrast to fungal dsRNA viruses. Comparisons of drug-treated LRV1+and LRV1-lines recapitulated LRV1-dependent pathology and parasite replication in mouse infections, and cytokine secretion in macrophage infections. Agents targeting Totiviridae have not been described previously, nor are there many examples of inhibitors acting against dsRNA viruses more generally. The compounds identified here provide a key proof-of-principle in support of further studies identifying efficacious antivirals for use in in vivo studies of LRV1-mediated virulence.
authors.affiliation: Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110.|Department of Medicine, Division of Infectious Diseases, Washington University School of Medicine in St. Louis, St. Louis, MO 63110.
authors.forename: F Matthew
authors.initials: FM
authors.lastname: Kuhlmann
authors.affiliation: Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110.
authors.forename: John I
authors.initials: JI
authors.lastname: Robinson
authors.affiliation: Emory Institute for Drug Development, Emory University, Atlanta, GA 30329.
authors.forename: Gregory R
authors.initials: GR
authors.lastname: Bluemling
authors.affiliation: Department of Biochemistry, University of Lausanne, 1066 Lausanne, Switzerland.
authors.forename: Catherine
authors.initials: C
authors.lastname: Ronet
authors.affiliation: Department of Biochemistry, University of Lausanne, 1066 Lausanne, Switzerland.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Fasel
authors.affiliation: Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110; stephen.beverley@wustl.edu.
authors.forename: Stephen M
authors.identifier: 0000-0001-5319-0811
authors.initials: SM
authors.lastname: Beverley
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D036022:Capsid Proteins / Q000235:genetics / Q000378:metabolism; D007892:Leishmania braziliensis / Q000821:virology*; D018334:Leishmania guyanensis / Q000821:virology*; D007896:Leishmaniasis / Q000469:parasitology; D019199:Leishmaniavirus / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D008810:Mice, Inbred C57BL; D009705:Nucleosides / Q000494:pharmacology*; D009711:Nucleotides / Q000494:pharmacology
chemical_list: D000998:Antiviral Agents; D036022:Capsid Proteins; D009705:Nucleosides; D009711:Nucleotides
keywords: chemotherapy; endobiont virus; trypanosomatid protozoan parasite; viral segregation; virulence