Effects of Choloroxoquinolinic ribonucleoside against the in vitro replication of HSV-1 and HIV-1.
Souza, T.M.L.1/3/4; Santos, C.V.B.2; Ferreira,V.F.2; Souza, M.C.B.2; Cirne, C.C.3; Bou-Habib, D.C.; 3Frugulhetti, I.C.P.P.4; Fontes, C.F.L.1
1-Universidade Federal do Rio de Janeiro, Instituto de Bioquímica Médica, Programa de Pós-graduação em Química Biológica, Av. Bahínia, 400, Ilha do Fundão, Rio de Janeiro, CEP 21941590, Rio de Janeiro, RJ, Brasil;
2-Universidade Federal Fluminense, Instituto de Química, Departamento de Química Orgânica, Outeiro de São João Batista s/no, Centro, Niterói, CEP 24210-150, Rio de Janeiro, Brasil;
3 – Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Departamento de Imunologia, Av. Brasil, 4365, Manguinhos, Rio de janeiro, CEP21045900, RJ, Brasil;
4-Universidade Federal Fluminense, Instituto de Biologia, Departamento de Biologia Celular e Molecular, Outeiro de São João Batista s/no, Centro, Niterói, CEP 24210-150, Rio de Janeiro, Brasil;
Herpes Simplex Virus 1 and Human Immunodeficience Virus 1 represent two of main viral pathogens of clinical relevance. The replication cycle of these viruses can be controlled reference compounds, such as Acyclovir and AZT, respectively. However, resistant strains of both viruses can emerge during HSV-1/HIV-1 co-infection. In addition, there are no antiviral compounds able to inhibit the replication of both viruses simultaneously. Therefore, based on an empiric seek, we studied the antiviral activities of the chloroxoquinolinic ribonucleoside (HupCl). This molecule showed an EC50 at the same range for both viruses (1,5mM) and a high CC50 (1500mM) for Vero cells and PBMC, the target cells for HSV and HIV, respectively. The time-course assay for HSV-1 indicates that the best inhibitory condition was achieved at 4-6 h post-infection, suggesting that this molecule is an Early inhibitor of viral replication. Subsequently, we confirmed the effect of HupCl on such step of viral replication by analyzing the protein profile of the host cell. Moreover, we found that the Early protein target for HupCl was the HSV-1 DNA polymerase (Ki=0,1mM). Consequently, we investigated whether the HIV-1 counterpart of the HSV-1 DNA polymerase, the enzyme Reverse Transcriptase (RT), could also be a target for HupCl. We observed that RNA-dependent DNA-polymerase activity of RT was inhibited by HupCl (Ki=0,5mM). Interestingly, the steady-sate kinetics of HupCl on dTTP uptake was characterized as a non-competitive inhibitor of HSV-1 DNA polymerase and an uncompetitive inhibitor of RT. Moreover, the RT-template/primer uptake was also inhibited in a competitive fashion. Curiously, HupCl inhibited HSV-1 DNA polymerase and HIV-1 RT activity even without phosphorylation. These findings uncover exciting opportunities to develop new antiviral agents that can inhibit the replication of two clinical relevant viral pathogens. More studies are in progress to determine the Kd values and the docking site of HupCl on both enzymes.
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