DISCOVERY OF NOVEL BOVINE VIRAL DIARRHEA ENTRY INHIBITORS

LEAL, EMILSE S.; ALDER, NATALIA; PACUAL, MARÍA JOSÉ; MARTINEFSKI, MANUELA; MONGE, MARÍA EUGENIA; ALVAREZ, DIEGO; BOLLINI, MARIELA

Congreso; Reunión Anual de Biociencia 2019 - SAIC-SAFE-SAB-SAP-NANOMEDar-AACyTAL-HSC; 2019

Bovine viral diarrhea virus (BVDV) is a pathogen of cattle that causes both acute and persistent infections, leading to substantial financial losses to the livestock industry each year. The global prevalence of persistent BVDV infection and the lack of an antiviral therapy have spurred efforts to discover and develop novel therapies in the pharmaceutical industry. Antiviral targeting of virus envelope proteins is an effective strategy for therapeutic intervention. We performed structure based virtual screening (SBVS) to identify molecules that likely bind to the region delimited by domains I and II of the envelope protein E2 of BVDV. Nineteen structurally different compounds were synthesized and evaluated in a reporter-based assay for antiviral activity. Compound PTC12 was the most active antiviral displaying an IC50 of 0.30 ± 0.13 μM against BVDV and selectivity index = 294. Also, PTC12 blocked virus entry at the stage of internalization. In order to validate the target, we performed selection and sequence analysis of drug-resistant mutants and identified R154Q as a candidate substitution associated to resistance. The mutation is located nearby the proposed binding pocket and MD simulations suggested a stable cation-π interaction between the N+ and the aromatic ring of PTC12. MM/PBSA calculations for the wild type and R154Q mutant indicate that PTC12 complexed with wt-BVDV had the most favorable binding energy (ΔGbind=-29.12 kcal/mol) whereas the complex with R154Q mutant caused a significant energetic change (ΔGbind=-21.6 kcal/mol).The physicochemical properties of PTC12 were evaluated in vitro: solubility was tested at three different pH values, and stability studies in media such as PBS, SIF, SGF, mouse or bovine plasma are currently ongoing.Altogether, we uncovered a novel druggable pocket in BVDV E2 that can be effectively targeted to block virus entry. SBVS against this target led to the identification of PTC12 as a potent BVDV inhibitor.