Browsing by Author "Lima, Rafaela Lameira Souza"

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    Antiviral effect of silymarin against Zika virus in vitro.
    (2020) Silva, Tales Fernando da; Ferraz, Ariane Coelho; Almeida, Letícia Trindade; Caetano, Camila Carla da Silva; Camini, Fernanda Caetano; Lima, Rafaela Lameira Souza; Andrade, Ana Cláudia dos Santos Pereira; Oliveira, Danilo Bretas de; Rocha, Kamila Lorene Soares; Silva, Breno de Mello; Magalhães, José Carlos de; Magalhães, Cíntia Lopes de Brito
    Zika virus (ZIKV) epidemic and its association with severe neurological syndromes have raised worldwide concern. Despite the great clinical relevance of this infection, no vaccine or specific treatment is available and the search for antiviral compounds against ZIKV is extremely necessary. Several natural compounds, such as silymarin, exhibit antioxidant, hepatoprotective, and antiviral properties; however, the antiviral potential of this compound remains partially investigated. Therefore, the objective of this study was to evaluate in vitro the antiviral activity of silymarin against ZIKV infection. Global antiviral activity, dose-dependent, plaque reduction, and time-of-drug-addition assays were used to determine the anti-ZIKV activity of silymarin. Additionally, to start characterizing the mechanisms of action we determined whether silymarin could have a virucidal effect and inhibit viral adsorption and penetration stages. Regarding its global antiviral activity, silymarin showed significant inhibition of ZIKV infection, protecting cells infected with EC50 equal to 34.17μg/mL, with a selectivity index greater than 17 and 4x greater than that of the positive control (ribavirin). Its greatest efficiency was achieved at 125μg/mL, whose cell viability did not differ from the control without infection and treatment. Furthermore, treatment with silymarin reduced viral load by up to two logs (> 90%) concerning viral control, when evaluating virucidal activity and the precocious times of infection. Thus, our results set to show the promising anti-ZIKV activity of silymarin, which does not seem to have a single inhibition mechanism, acting at different times of infection, and still has the advantage of silymarin be a phytotherapy already available on the market.
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    Avaliação da atividade antioxidante e antiviral da Silimarina e N-acetilcisteína em camundongos C57BL/6 infectados com o vírus Zika e o papel da espécies reativas de oxigênio na multiplicação viral.
    (2021) Lima, Rafaela Lameira Souza; Magalhães, Cíntia Lopes de Brito; Magalhães, Cíntia Lopes de Brito; Costa, Daniela Caldeira; Brandão, Geraldo Célio
    O Zika virus (ZIKV) é um arbovírus que pertence à família Flaviviridae e ao gênero Flavivirus, transmitido principalmente pelos mosquitos Aedes aegypti e Aedes albopictus. Os principais sintomas causados pela infecção por ZIKV são febre, exantema, artralgia, mialgia, conjuntivite e cefaleia. No entanto, estudos têm demonstrado a possível ligação entre a infecção por ZIKV e alguns distúrbios neurológicos, como microcefalia em bebês e síndrome de Guillian-Barré em adultos. Embora essa arbovirose seja de grande importância para a Saúde Pública nacional, apresentando quadros debilitantes, até o momento não existem fármacos e/ou vacinas disponíveis para o tratamento da doença. Nesse sentido, uma vez que nosso grupo de pesquisa já demonstrou que o estresse oxidativo ocorre na infecção por ZIKV tanto in vitro como in vivo e que a Silimarina, um fitoterápico com ação antioxidante e anti-inflamatória bem conhecida, tem ação antiviral contra o vírus in vitro, o objetivo deste trabalho foi avaliar in vivo a atividade antiviral e antioxidante da Silimarina em camundongos infectados com ZIKV. Além da Silimarina, a Nacetilcisteína (NAC) foi inserida no estudo para verificar se a atividade antioxidante da Silimarina poderia estar associada à atividade antiviral, por meio da comparação com um antioxidante já conhecido que até então não possuía atividade antiviral contra o vírus. Para isso, camundongos C57BL/6 foram infectados via intraperitoneal com 10^8 (dez elevado a 8) Unidades Formadoras de Placa (UFP) do ZIKV e divididos em 6 grupos, sendo eles: grupo controle (C); grupo controle + silimarina (CSIL); grupo infectado (V); grupo infectado + silimarina (VSIL); grupo controle + NAC (CNAC); grupo infectado + NAC (VNAC). Os animais tratados com Silimarina receberam 200mg/kg/dia, enquanto os tratados com NAC 300mg/kg/dia via gavagem, de 12/12 horas, sendo que os tratamentos se iniciaram 24h antes da infecção. Após 3 dias da infecção, os animais foram eutanasiados e no fígado dos camundongos foram mensurados os biomarcadores de estresse oxidativo, assim como as enzimas antioxidantes Superóxido Dismutase (SOD) e Catalase (CAT). Ainda, a carga viral foi avaliada no fígado. Nossos resultados demonstraram que o tratamento com a Silimarina e NAC se mostrou promissor no restabelecimento dos parâmetros redox no fígado de camundongos C57BL/6 infectados com ZIKV e ambos compostos apresentaram atividade antiviral, reduzindo a carga viral no fígado de camundongos infectados. Como os dois compostos apresentaram atividade antiviral, o próximo objetivo foi avaliar in vitro se todo antioxidante para ZIKV poderia também ser um antiviral. Para isso, além da Silimarina e NAC, foram testados os antioxidantes Quercetina e Rutina. Para a realização desses experimentos foram utilizadas células Vero, infectadas com ZIKV em uma multiplicidade de infecção (MOI) de 5 e tratadas com diferentes concentrações dos compostos. Os resultados in vitro mostraram que todos os compostos testados exerceram efeito antioxidante por inibirem a produção de “Espécies Reativas de Oxigênio” (ERO) após a infecção. No entanto, somente a Silimarina apresentou atividade anti-ZIKV, confirmando estudos prévios do grupo. Assim, nossos resultados indicam que a multiplicação do ZIKV parece não depender das ERO uma vez que a atividade antioxidante dos compostos não necessariamente resultou em efeito antiviral. No entanto, mais estudos precisam ser realizados para confirmar essa hipótese. Em conjunto, os resultados obtidos reforçam o potencial do efeito antiviral e antioxidante da Silimarina na infecção pelo ZIKV e abrem perspectivas do seu uso como abordagem farmacológica.
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    Hepatoprotective, antioxidant, anti-inflammatory, and antiviral activities of silymarin against mayaro virus infection.
    (2021) Ferraz, Ariane Coelho; Almeida, Letícia Trindade; Caetano, Camila Carla da Silva; Menegatto, Marília Bueno da Silva; Lima, Rafaela Lameira Souza; Senna, João Pinto Nelson de; Cardoso, Jamille Mirelle de Oliveira; Perucci, Luiza Oliveira; Silva, André Talvani Pedrosa da; Lima, Wanderson Geraldo de; Silva, Breno de Mello; Reis, Alexandre Barbosa; Magalhães, José Carlos de; Magalhães, Cíntia Lopes de Brito
    Infection caused by Mayaro virus (MAYV) is responsible for causing acute nonspecific fever, in which the ma- jority of patients develop incapacitating and persistent arthritis/arthralgia. Mayaro fever is a neglected and underreported disease without treatment or vaccine, which has gained attention in recent years after the competence of Aedes aegypti to transmit MAYV was observed in the laboratory, coupled with the fact that cases are being increasingly reported outside of endemic forest areas, calling attention to the potential of an urban cycle arising in the near future. Thus, to mitigate the lack of information about the pathological aspects of MAYV, we previously described the involvement of oxidative stress in MAYV infection in cultured cells and in a non- lethal mouse model. Additionally, we showed that silymarin, a natural compound, attenuated MAYV-induced oxidative stress and inhibited MAYV replication in cells. The antioxidant and anti-MAYV effects prompted us to determine whether silymarin could also reduce oxidative stress and MAYV replication after infection in an immunocompetent animal model. We show that infected mice exhibited reduced weight gain, hepatomegaly, splenomegaly, anaemia, thrombocytopenia, leukopenia, increased liver transaminases, increased pro- inflammatory cytokines and liver inflammation, increased oxidative damage biomarkers, and reduced antioxi- dant enzyme activity. However, in animals infected and treated with silymarin, all these parameters were reversed or significantly improved, and the detection of viral load in the liver, spleen, brain, thigh muscle, and footpad was significantly reduced. This work reinforces the potent hepatoprotective, antioxidant, anti- inflammatory, and antiviral effects of silymarin against MAYV infection, demonstrating its potential against Mayaro fever disease.
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    Mayaro virus induction of oxidative stress is associated with liver pathology in a non-lethal mouse model.
    (2019) Caetano, Camila Carla da Silva; Camini, Fernanda Caetano; Almeida, Letícia Trindade; Ferraz, Ariane Coelho; Silva, Tales Fernando da; Lima, Rafaela Lameira Souza; Carvalho, Mayara Medeiros de Freitas; Castro, Thalles de Freitas; Carneiro, Cláudia Martins; Silva, Breno de Mello; Silva, Silvana de Queiroz; Magalhães, José Carlos de; Magalhães, Cíntia Lopes de Brito
    Mayaro virus (MAYV) causes Mayaro fever in humans, a self-limiting acute disease, with persistent arthralgia and arthritis. Although MAYV has a remerging potential, its pathogenic mechanisms remain unclear. Here, we characterized a model of MAYV infection in 3–4-week BALB/c mice. We investigated whether the liver acts as a site of viral replication and if the infection could cause histopathological alterations and an imbalance in redox homeostasis, culminating with oxidative stress. MAYV-infected mice revealed lower weight gain; however, the disease was self-resolving. High virus titre, neutralizing antibodies, and increased levels of aspartate and alanine aminotransferases were detected in the serum. Infectious viral particles were recovered in the liver of infected animals and the histological examination of liver tissues revealed significant increase in the inflammatory infiltrate. MAYV induced significant oxidative stress in the liver of infected animals, as well as a deregulation of enzymatic antioxidant components. Collectively, this is the first study to report that oxidative stress occurs in MAYV infection in vivo, and that it may be crucial in virus pathogenesis. Future studies are warranted to address the alternative therapeutic strategies for Mayaro fever, such as those based on antioxidant compounds.
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    Zika virus induces oxidative stress and decreases antioxidant enzyme activities in vitro and in vivo.
    (2020) Almeida, Letícia Trindade; Ferraz, Ariane Coelho; Caetano, Camila Carla da Silva; Menegatto, Marília Bueno da Silva; Andrade, Ana Cláudia dos Santos Pereira; Lima, Rafaela Lameira Souza; Camini, Fernanda Caetano; Pereira, Samille Henriques; Pereira, Karla Yanca da Silva; Silva, Breno de Mello; Perucci, Luiza Oliveira; Silva, André Talvani Pedrosa da; Magalhães, José Carlos de; Magalhães, Cíntia Lopes de Brito
    The first outbreak of Zika virus (ZIKV) infection in the Americas, especially in Brazil, was reported in 2015. Fever, headache, rash, and conjunctivitis are the common symptoms of ZIKV infection. Unexpected clinical outcomes, such as microcephaly and Guillain-Barré syndrome, have also been reported. The recent spread of ZIKV and its association with severe illness has created an urgent need to understand its pathogenesis and find potential therapeutic targets. Studies show that some viruses, including Flavivirus, trigger oxidative stress, which affects cellular metabolism, viral cycle, and pathogenesis. However, the role of oxidative stress in ZIKV infection needs to be investigated. Here, we analyzed ZIKV infection-triggered oxidative stress and modified antioxidant enzyme activities. U87-MG and HepG2 cells were infected to measure reactive oxygen species (ROS), malondialdehyde (MDA), and carbonyl protein levels, the activities of superoxide dismutase (SOD) and catalase (CAT), and the activation of nuclear factor erythroid 2p45-related factor 2 (Nrf2). ZIKV infection induced a significant increase in ROS, lipid peroxidation, and protein carbonylation products and a significant decrease in SOD and CAT activities accompanied by inhibition of Nrf2 activation in both cell lines. Further, MDA and carbonyl protein levels and SOD and CAT activities were evaluated in the brain and liver of ZIKV-infected C57BL/6 mice, and oxidative stress associated with antioxidant depletion was also found to occur in vivo. Together, our findings indicate the potential use of antioxidants as a novel therapeutic approach to Zika disease, and future studies in this direction are warranted.