Mining a Kröhnke Pyridine Library for Anti-Arenavirus Activity

Abstract

Several arenaviruses cause hemorrhagic fever (HF) disease in humans and represent important public health problems in their endemic regions. In addition, evidence indicates that the worldwide-distributed prototypic arenavirus lymphocytic choriomeningitis virus is a neglected human pathogen of clinical significance. There are no licensed arenavirus vaccines, and current antiarenavirus therapy is limited to an off-label use of ribavirin that is only partially effective. Therefore, there is an unmet need for novel therapeutics to combat human pathogenic arenaviruses, a task that will be facilitated by the identification of compounds with antiarenaviral activity that could serve as probes to identify arenavirus-host interactions suitable for targeting, as well as lead compounds to develop future antiarenaviral drugs. Screening of a combinatorial library of Krönhke pyridines identified compound KP-146 [(5-(5-(2,3-dihydrobenzo[ b][1,4] dioxin-6-yl)-4'-methoxy-[1,1'-biphenyl]-3-yl)thiophene-2-carboxamide] as having strong anti-lymphocytic choriomeningitis virus (LCMV) activity in cultured cells. KP-146 did not inhibit LCMV cell entry but rather interfered with the activity of the LCMV ribonucleoprotein (vRNP) responsible for directing virus RNA replication and gene transcription, as well as with the budding process mediated by the LCMV matrix Z protein. LCMV variants with increased resistance to KP-146 did not emerge after serial passages in the presence of KP-146. Our findings support the consideration of Kröhnke pyridine scaffold as a valuable source to identify compounds that could serve as tools to dissect arenavirus-host interactions, as well as lead candidate structures to develop antiarenaviral drugs.

Segmented, Negative-Sense RNA Viruses of Humans: Genetic Systems and Experimental Uses of Reporter Strains

“…These include the replacement of wild-type viral GPC or NP segments with eGFP (104,106,107,(114)(115)(116)(117)(118)(119)(120)(121)(122)(123)(124), teal fluorescent protein (125), mCherry (126,127), or ZsGreen (128)(129)(130). Not only do these reporters allow for assessment of viral replication in less time than is needed for traditional plaque assays, but also they have been a powerful tool in highthroughput screening approaches used to identify small-molecule antivirals (131), identification of receptors required for host cell infection (126), and the discovery that LCMV can cause long-term immune dysfunction months after infection (125), among many other important discoveries.…”

A cell-based, infectious-free, platform to identify inhibitors of lassa virus ribonucleoprotein (vRNP) activity

“…LASV/vRNP cells were maintained in DMEM 10% FBS, 100 μg/ml zeocin, 10 μg/ml Bls, 100 mg/ml streptomycin, and 100 U/ ml penicillin. The recombinant (r)LCMV expressing GFP (rLCMV/GFP-P2A-NP, refer to as rLCMV/GFP) (Miranda et al, 2018), ZsGreen (ZsG) (rLCMV/ZsG-P2A-NP, refer to as rLCMV/ZsG) , and a single cycle infectious rLCMV expressing ZsG (rLCMVΔGPC/ZsG-P2A-NP, refer to as rLCMVΔGPC/ZsG) have been described.…”

“…The L RNA encodes the viral RNA dependent RNA polymerase (L polymerase), and the matrix Z protein. Advances in mammarenavirus molecular genetics have opened new approaches for the development of screening strategies to identify inhibitors of mammarenavirus multiplication Emonet et al, 2011a;Miranda et al, 2018;Welch et al, 2016). However, the use of these approaches with live LASV are complicated by the requirement of biosafety level 4 (BSL4) containment.…”

Hemorrhagic Fever-Causing Arenaviruses: Lethal Pathogens and Potent Immune Suppressors

“…Lethal viral mutagenesis has also been identified as a possible mechanism for viral control (403, 404). While few studies have found drugs that target arenaviral NPs, one recent paper has identified a compound from a pyridine library that can reduce LCMV titers post-cell entry and is thought to affect NP and Z by unknown mechanisms (405).…”