Chikungunya virus entry is strongly inhibited by phospholipase A2 isolated from the venom of Crotalus durissus terrificus

AbstractChikungunya virus (CHIKV) is the etiologic agent of Chikungunya fever, a globally spreading mosquito-borne disease. There is no approved antiviral or vaccine against CHIKV, highlighting an urgent need for novel therapies. In this context, snake venom proteins have demonstrated antiviral activity against several viruses, including arboviruses which are relevant to public health. In particular, the phospholipase A2CB (PLA2CB), a protein isolated from the venom of Crotalus durissus terrificus was previously shown to possess anti-inflammatory, antiparasitic, antibacterial and antiviral activities. In this study, we investigated the multiple effects of PLA2CB on the CHIKV replicative cycle in BHK-21 cells using CHIKV-nanoluc, a marker virus carrying nanoluciferase reporter. The results demonstrated that PLA2CB possess a strong anti-CHIKV activity with a selectivity index of 128. We identified that PLA2CB treatment protected cells against CHIKV infection, strongly impairing virus entry by reducing adsorption and post-attachment stages. Moreover, PLA2CB presented a modest yet significant activity towards post-entry stages of CHIKV replicative cycle. Molecular docking calculations indicated that PLA2CB may interact with CHIKV glycoproteins, mainly with E1 through hydrophobic interactions. In addition, infrared spectroscopy measurements indicated interactions of PLA2CB and CHIKV glycoproteins, corroborating with data from in silico analyses. Collectively, this data demonstrated the multiple antiviral effects of PLA2CB on the CHIKV replicative cycle, and suggest that PLA2CB interacts with CHIKV glycoproteins and that this interaction blocks binding of CHIKV virions to the host cells.

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Organometallic Complex Strongly Impairs Chikungunya Virus Entry to the Host Cells

Frontiers in Microbiology ◽

10.3389/fmicb.2020.608924 ◽

2020 ◽

Vol 11 ◽

Author(s):

Débora Moraes de Oliveira ◽

Igor de Andrade Santos ◽

Daniel Oliveira Silva Martins ◽

Yasmim Garcia Gonçalves ◽

Léia Cardoso-Sousa ◽

...

Keyword(s):

Chikungunya Virus ◽

Hydrophobic Interactions ◽

Therapeutic Potential ◽

Virus Entry ◽

Antiviral Treatment ◽

Host Cells ◽

Virus Infectivity ◽

Chloride Salt ◽

Organometallic Complex ◽

Chikv Infection

Chikungunya fever is a disease caused by the Chikungunya virus (CHIKV) that is transmitted by the bite of the female of Aedes sp. mosquito. The symptoms include fever, muscle aches, skin rash, and severe joint pains. The disease may develop into a chronic condition and joint pain for months or years. Currently, there is no effective antiviral treatment against CHIKV infection. Treatments based on natural compounds have been widely studied, as many drugs were produced by using natural molecules and their derivatives. Alpha-phellandrene (α-Phe) is a naturally occurring organic compound that is a ligand for ruthenium, forming the organometallic complex [Ru2Cl4(p-cymene)2] (RcP). Organometallic complexes have shown promising as candidate molecules to a new generation of compounds that presented relevant biological properties, however, there is a lack of knowledge concerning the anti-CHIKV activity of these complexes. The present work evaluated the effects of the RcP and its precursors, the hydrate ruthenium(III) chloride salt (RuCl3⋅xH2O) (Ru) and α-Phe, on CHIKV infection in vitro. To this, BHK-21 cells were infected with CHIKV-nanoluciferase (CHIKV-nanoluc), a viral construct harboring the nanoluciferase reporter gene, at the presence or absence of the compounds for 16 h. Cytotoxicity and impact on infectivity were analyzed. The results demonstrated that RcP exhibited a strong therapeutic potential judged by the selective index > 40. Antiviral effects of RcP on different stages of the CHIKV replicative cycle were investigated; the results showed that it affected early stages of virus infection reducing virus replication by 77% at non-cytotoxic concentrations. Further assays demonstrated the virucidal activity of the compound that completely blocked virus infectivity. In silico molecular docking calculations suggested different binding interactions between aromatic rings of RcP and the loop of amino acids of the E2 envelope CHIKV glycoprotein mainly through hydrophobic interactions. Additionally, infrared spectroscopy spectral analysis indicated interactions of RcP with CHIKV glycoproteins. These data suggest that RcP may act on CHIKV particles, disrupting virus entry to the host cells. Therefore, RcP may represent a strong candidate for the development of anti-CHIKV drugs.

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