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Development of the diagnostic method for rocio virus and use of new compounds as inhibitors of flavivirus protease-helicase NS2B-NS3

Grant number: 20/12875-5
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): January 01, 2021
Effective date (End): December 31, 2024
Field of knowledge:Biological Sciences - Microbiology
Principal Investigator:Maurício Lacerda Nogueira
Grantee:Marielena Vogel Saivish
Home Institution: Faculdade de Medicina de São José do Rio Preto (FAMERP). Secretaria de Desenvolvimento Econômico (São Paulo - Estado). São José do Rio Preto , SP, Brazil


Arboviruses, constituted by viruses of medical importance, their main representatives include mainly viruses belonging to the genus Flavivirus. It is noteworthy that in several tropical and subtropical countries, including Brazil, these viruses have emerged and represent one of the main public health problems because they cause constant epidemics and outbreaks such as the Dengue virus (DENV), Zika virus (ZIKV) and Yellow Fever virus (YFV) recently. In addition, the constant epidemics increase the number of people who seek medical care and cause an overload in the public health network, resulting in high economic costs for the affected countries. The purpose of this study is the development and standardization of an indirect ELISA-peptide test for Rocio flavivirus (ROCV), in addition to the identification of isolated compounds as inhibitors of NS2B-NS3 of flavivirus; both initially selected through computational studies and molecular dynamics, with later confirmation and validation through in vitro tests. The silent circulation of the Rocio virus has recently been identified in the population, and the development of an inexpensive, sensitive and specific diagnostic method is extremely necessary in view of the scarcity of tests to identify such a virus. Partial results of the study point to a unique peptide sequence of the Rocio virus, not present in other flaviviruses, obtained through protein analysis of the molecular dynamics of viral NS1. Analyzes of antigenic prediction for the peptide were performed, showing a high antigenicity score in silico. Partial results from the present study also demonstrate that flavonoids isolated from natural products Amentoflavone, Tetrahidrrorobustaflavone and Quercitin are inhibitors of the proteases NS2B-NS3 of West Nile, Rocio, Ilheus, Yellow Fever, Encephalitis de Saint-Louis and Dengue. The NS2B-NS3 protein complex is a serine protease of viruses of the genus Flavivirus, being considered a key target in the search for new antiviral drugs. Our anchorage studies propose a way of binding the flavonoids to a specific allosteric binding site of the enzyme. Our initial results help to understand the mechanism of inhibition of the serine protease of these viruses by flavonoids, essential for the development of improved inhibitors from these isolated molecules. The objective is to conclude and confirm the results of the present study obtained in silico, as well as to seek confirmation of the results obtained by conducting in vitro tests. (AU)