https://repositorio.ufu.br/handle/123456789/5487 Tue, 06 Oct 2026 05:39:25 GMT 2026-10-06T05:39:25Z https://repositorio.ufu.br/handle/123456789/50508 Title: Estruturas secundárias G-quadruplex no genoma do vírus Mayaro como alvo para estratégias antivirais Abstract: The Mayaro virus (MAYV) is a mosquito-borne arthritogenic alphavirus and the etiologic agent of Mayaro fever. The infection is characterized by debilitating clinical manifestations, such as fever, myalgia, prolonged arthralgia, and ocular pain. MAYV circulates in several countries across the Americas and notably in Brazil, where cases are detected annually. Currently, there are no licensed antiviral drugs for the treatment of this viral infection. In this context, G-quadruplexes (G4s), secondary structures formed within viral genomes, have gained prominence due to their involvement in controlling essential processes of the viral replication cycle, emerging as potential therapeutic targets. Therefore, the present study aimed to identify G4 structures in the MAYV genome and evaluate their potential as targets for antiviral strategies. To achieve this goal, in silico analyses using the predictors QGRS Mapper, pqsfinder, and G4Hunter initially identified putative G4-forming sequences (PQS) within the genomes of genotypes L and D. Alignment of the complete genomic sequences revealed the presence of conserved PQS exclusive to genotypes L and D, as well as sequences common across all genotypes. Based on these predictions, the PQS located in the coding region of the nsP2 protein (RNA_3411) was selected for structural characterization. Circular dichroism (CD) analyses suggested that this sequence adopts a hybrid and antiparallel topological profile in the presence of stabilizing ions. Additionally, dose-response assays in Vero E6 cells infected with MAYV-NanoLuc demonstrated that treatment with the G4 ligands TMPyP4, BRACO-19, and NMM inhibited viral replication in a dose-dependent manner, resulting in selectivity indices (SI) of >12.4, 2.0, and >2.5, respectively. Furthermore, time-of-drug-addition (ToDA) assays revealed that TMPyP4 exhibits antiviral activity during the post-entry stage of the replication cycle, significantly reducing intra- and extracellular viral titers. Complementary CD assays showed that the interaction between TMPyP4 and RNA_3411 induces conformational rearrangements in the G4 topologies. Finally, assays using antisense oligonucleotides (ASO) targeting MAYV PQS inhibited viral replication by approximately 50% when used alone, and did not interfere with the activity of the TMPyP4 ligand when co-administered. Our results demonstrate the formation of G4 structures in the MAYV genome and suggest that the modulation of these structures by ligands represents a promising antiviral strategy. Tue, 28 Jul 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/50508 2026-07-28T00:00:00Z https://repositorio.ufu.br/handle/123456789/50272 Title: Desenvolvimento e validação de construções do vírus Mayaro com genes de luciferase como ferramentas para ensaios antivirais Abstract: The Mayaro virus (MAYV), an arbovirus from the Alphavirus genus and Togaviridae family, is the etiologic agent of Mayaro fever. Endemic in South and Central Americas, it is maintained in animal reservoirs within a sylvatic cycle. However, the virus exhibits high adaptability to new hosts and vectors, establishing an urban cycle. Mayaro fever presents symptoms similar to other arboviruses, potentially resulting in long-term polyarthritis and polyarthralgia. Currently, there is no licensed vaccine or antiviral treatment against MAYV, which contributes to virus dissemination. In this context, this work aimed to develop viral constructs for use in high-throughput antiviral research. The plasmids were produced by reverse genetics, based on the MAYV BeAr 20290 strain, containing human cytomegalovirus promoter and nanoluciferase (CMV-MAYV-nanoluc) and firefly luciferase (CMV-MAYV-firefly) reporter genes. The luminescence genes were inserted into the viral genome between the end of nsP4 and the 5' terminus of the structural genes. Subsequently, this viral genome segment was combined with a CMV promoter obtained through polymerase chain reaction (PCR). After sequencing, the plasmids were amplified using competent DH5-α bacteria. Subsequently, CMV-MAYV-nanoluc and CMV-MAYV-firefly were transfected into Vero E6 cells, generating infectious MAYV-nanoluc and MAYV-firefly particles, respectively. The viruses replicated efficiently with properties similar to the parental wild-type MAYV, and the expression of the reporter genes reflected viral replication rates. Additionally, using MAYV-nanoluc, we analyzed the repositioning potential of rimantadine hydrochloride (rtdH), licensed drug for the treatment of Influenza, as an anti-MAYV agent. The drug inhibited MAYV with an SI of 2.3 and also showed activity against Zika virus (ZIKV) with an SI of 2.4. Additionally, the compound EIDD-2749, described as an inhibitor of RNA-dependent RNA polymerase with potent antiviral activity against alphavirus, was used to validate the MAYV-nanoluc tool for antiviral trials, with an SI of 1.8 x 107. Our data demonstrated that the MAYV-nanoluc clone is a valuable tool for antiviral assays, enhancing the screening of new anti-MAYV agents. Furthermore, rtdH showed a broad-spectrum antiviral activity against MAYV and ZIKV. Fri, 23 Aug 2024 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/50272 2024-08-23T00:00:00Z https://repositorio.ufu.br/handle/123456789/49796 Title: Impacto dos subtipos moleculares e variáveis clínico-patológicas nos desfechos do câncer de mama: um estudo entre grandes bases de dados Abstract: Breast cancer represents a major global health challenge, and the use of publicly available databases can contribute to a more comprehensive understanding of disease patterns. Given the potential of these data sources to support complementary analyses, this study aimed to explore different publicly available databases to investigate demographic, tumor, and therapeutic characteristics of breast cancer. An observational, retrospective study was conducted using hospital-based, population-based, and molecular records from four databases: the São Paulo Hospital-Based Cancer Registry (HBCR), the National HBCR, the Surveillance, Epidemiology, and End Results (SEER) Program, and the genomic and clinical data from the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC). Together, these four databases comprised 1,128,269 breast cancer records. Diagnoses were made between 2000 and 2015, except for the METABRIC database. Fine-Gray competing risks modeling was employed to evaluate tumor recurrence over a 120-month follow-up period, stratified into two time intervals (0–60 and 61–120 months). Cox proportional hazards models were applied to estimate 5-year overall and cause-specific survival. Road travel distances to cancer treatment facilities in Brazil were estimated using the geobr and osrm statistical packages. All analyses were performed in the RStudio computing environment, version 2026.01.1+403. Independent predictors of the average risk of tumor recurrence included tumor size, the number of positive lymph nodes, histological grade 3, and intrinsic molecular subtypes defined by the PAM50 gene expression signature. Temporal dynamics analysis demonstrated that the risk of tumor recurrence was not constant over time. Regarding 5-year survival, age and tumor stage were independent predictors of the average risk of overall and cause-specific mortality. Year of diagnosis was inversely associated with the risk of cause-specific mortality, serving as a temporal marker of changes occurring throughout the study period. An average reduction of 2.81% in the Sâo Paulo HBCR and 2.96% in the population-based registry was observed in the risk of cause-specific mortality for each more recent year of diagnosis. In the National HBCR, 52.09% of the sample received treatment outside their municipality of residence. Median road travel distances by treatment modality ranged from 76.6 km for hormone therapy to 114.0 km for immunotherapy. Geographic mapping revealed inequalities in the distribution of oncology services, demonstrating that treatment centers were highly concentrated in the Southeast, South, and Northeast regions of Brazil. The study concludes that different databases provide complementary information that expands the analytical capabilities for investigating breast cancer outcomes, enabling analyses that would not be possible using a single data source. These findings highlight the value of combining information from multiple data sources to support researchers and healthcare decision-makers in monitoring disease patterns and planning oncology care strategies. Tue, 03 Nov 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/49796 2026-11-03T00:00:00Z https://repositorio.ufu.br/handle/123456789/49440 Title: Desenvolvimento de estratégias antivirais frente a vírus emergentes Abstract: Emerging viruses pose growing threats to public health, particularly in Brazil, where environmental and sociodemographic factors favour epidemic outbreaks. This work aimed to identify and characterise antiviral compounds against the emerging viruses Orthobunyavirus oropoucheense (OROV) and Betacoronavirus pandemicum (SARS-CoV-2) through medium-throughput screening of the Pandemic Response Box (PRB) and Global Health Priority Box (GHPB) libraries from the Medicines for Malaria Venture (MMV). OROV is the causative agent of Oropouche fever, which caused over 13,000 cases in Brazil in 2024, with unprecedented geographical expansion, vertical transmission, neurological complications and confirmed fatalities, with no approved antiviral treatment available. SARS-CoV-2, responsible for the COVID-19 pandemic with over 779 million cases recorded through 2026, remains a therapeutic challenge, particularly against the Delta and Omicron variants of concern. The experimental approach employed fluorescent reporter viruses, BUNV-eGFP (Bunyamwera virus with an enhanced green fluorescent protein reporter) as a prototypic model for OROV, and SARS-CoV-2-mCherry (SARS-CoV-2 with a monomeric red fluorescent protein reporter) for direct screening, in A549 and A549-AT cells, with automated readout using the IncuCyte S3 system. Of the 640 compounds tested, active hits were identified and validated for both viral targets. Against OROV, nine compounds from the PRB inhibited BUNV replication by more than 90%. Following validation against wild-type OROV (epidemic strain AM0088), three hits were confirmed: Trimetrexate, MMV1634385, and GSK-983, being GSK the compound with greatest inhibition (EC50 = 0.5 μM against OROV; DHODH inhibitor; SI > 20), reported here for the first time as an anti-orthobunyavirus compound and identified as the most promising candidate. Against SARS-CoV-2, two hits were mechanistically characterised. Revaprazan (EC50 = 1.3 μM; SI > 7.7), a clinically approved potassium-competitive acid blocker (P-CAB), inhibited viral entry while retaining activity against Delta and Omicron BA.2, representing the first report of antiviral activity for a P-CAB-class compound. Milbemectin (EC50 = 1.6 μM; SI > 6), a milbemycin-class macrolide antiparasitic structurally related to ivermectin, acted predominantly at post-entry stages, interfering with virion assembly and egress. Together, these findings establish GSK-983, Revaprazan and Milbemectin as priority candidates for preclinical investigation, expand the antiviral spectrum of compounds with established safety profiles, and validate the fluorescent reporter-based screening platform as a robust strategy for antiviral discovery against emerging viral threats. Fri, 31 Jul 2026 00:00:00 GMT https://repositorio.ufu.br/handle/123456789/49440 2026-07-31T00:00:00Z