Identification of novel Zika virus NS3 protease inhibitors with different inhibition modes by integrative experimental and computational approaches.

Zika virus (ZIKV) infection is associated with severe neurological disorders and congenital malformation. Despite efforts to eradicate the disease, there is still neither vaccine nor approved drugs to treat ZIKV infection. The NS2B-NS3 protease is a validated drug target since it is essential to polyprotein virus maturation. In the present study, we describe an experimental screening of 2,320 compounds from the chemical library of the Muséum National d'Histoire Naturelle of Paris on ZIKV NS2B-NS3 protease. A total of 96 hits were identified with 90% or more of inhibitory activity at 10 µM. Amongst the most active compounds, five were analyzed for their inhibitory mechanisms by kinetics assays and computational approaches such as molecular docking. 2-(3-methoxyphenoxy) benzoic acid (compound 945) show characteristics of a competitive inhibition (Ki = 0.49 µM) that was corroborated by its molecular docking at the active site of the NS2B-NS3 protease. Taxifolin (compound 2292) behaves as an allosteric inhibitor whereas 3,8,9-trihydroxy-2-methyl-1H-phenalen-1-one (compound 128), harmol (compound 368) and anthrapurpurin (compound 1499) show uncompetitive inhibitions. These new NS2B-NS3 protease inhibitors are valuable hits to further hit-to-lead optimization.

Liposomes Composed by Membrane Lipid Extracts from Macrophage Cell Line as a Delivery of the Trypanocidal N,N'-Squaramide 17 towards Trypanosoma cruzi.

Chagas is a neglected tropical disease caused by Trypanosoma cruzi, and affects about 25 million people worldwide. N, N'-Squaramide 17 (S) is a trypanocidal compound with relevant in vivo effectiveness. Here, we produced, characterized, and evaluated cytotoxic and trypanocidal effects of macrophage-mimetic liposomes from lipids extracted of RAW 264.7 cells to release S. As results, the average hydrodynamic diameter and Zeta potential of mimetic lipid membranes containing S (MLS) was 196.5 ± 11 nm and -61.43 ± 2.3 mV, respectively. Drug entrapment efficiency was 73.35% ± 2.05%. After a 72 h treatment, MLS was observed to be active against epimastigotes in vitro (IC50 = 15.85 ± 4.82 µM) and intracellular amastigotes (IC50 = 24.92 ± 4.80 µM). Also, it induced low cytotoxicity with CC50 of 1199.50 ± 1.22 µM towards VERO cells and of 1973.97 ± 5.98 µM in RAW 264.7. MLS also induced fissures in parasite membrane with a diameter of approximately 200 nm in epimastigotes. MLS showed low cytotoxicity in mammalian cells and high trypanocidal activity revealing this nanostructure a promising candidate for the development of Chagas disease treatment.