Two coding variants of apolipoprotein L1 (APOL1), called G1 and G2, explain much of the excess risk of kidney disease in African Americans. While various cytotoxic phenotypes have been reported in experimental models, the proximal mechanism by which G1 and G2 cause kidney disease is poorly understood. Here, we leveraged 3 experimental models and a recently reported small molecule blocker of APOL1 protein, VX-147, to identify the upstream mechanism of G1-induced cytotoxicity. In HEK293 cells, we demonstrated that G1-mediated Na⁺ import/K⁺ efflux triggered activation of GPCR/IP3–mediated calcium release from the ER, impaired mitochondrial ATP production, and impaired translation, which were all reversed by VX-147. In human urine-derived podocyte-like epithelial cells (HUPECs), we demonstrated that G1 caused cytotoxicity that was again reversible by VX-147. Finally, in podocytes isolated from APOL1 G1 transgenic mice, we showed that IFN-γ–mediated induction of G1 caused K⁺ efflux, activation of GPCR/IP3 signaling, and inhibition of translation, podocyte injury, and proteinuria, all reversed by VX-147. Together, these results establish APOL1-mediated Na⁺/K⁺ transport as the proximal driver of APOL1-mediated kidney disease.

Espirito Santo virus (ESV) is a newly discovered virus recovered as contamination in a sample of a virulent strain of dengue-2 virus (strain 44/2), which was recovered from a patient in the state of Espirito Santo, Brazil, and amplified in insect cells. ESV was found to be dependent upon coinfection with a virulent strain of dengue-2 virus and to replicate in C6/36 insect cells but not in mammalian Vero cells. A sequence of the genome has been produced by de novo assembly and was not found to match to any known viral sequence. An incomplete match to the nucleotide sequence of the RNA-dependent RNA polymerase from Drosophila X virus (DXV), another birnavirus, could be detected. Mass spectrometry analysis of ESV proteins found no matches in the protein data banks. However, peptides recovered by mass spectrometry corresponded to the de novo -assembled sequence by BLAST analysis. The composition and three-dimensional structure of ESV are presented, and its sequence is compared to those of other members of the birnavirus family. Although the virus was found to belong to the family Birnaviridae , biochemical and sequence information for ESV differed from that of DXV, the representative species of the genus Entomobirnavirus . Thus, significant differences underscore the uniqueness of this infectious agent, and its relationship to the coinfecting virus is discussed.

Resumo: A circulação simultânea da dengue, Zika e chikungunya impõe desafios importantes para o Brasil, que em decorrência das mudanças climáticas e outros fatores associados, estas arboviroses podem expor mais de 2 bilhões de pessoas no mundo, segundo a Organização Mundial da Saúde. A principal estratégia dos programas de controle do Aedes aegypti baseia-se no Levantamento de Índice Rápido para o Ae. aegypti (LIRAa), um inquérito amostral no qual o Índice de Infestação Predial (IIP) obtido é utilizado para priorizar áreas de intervenção. Neste estudo, analisou-se o desempenho do LIRAa quanto à sua sensibilidade na previsão de epidemias de dengue em municípios do Estado do Rio de Janeiro, em anos considerados epidêmicos. Foram obtidas as taxas de incidência (TI) por município nos anos de 2011, 2012, 2013, 2015 e 2016, e os IIP de outubro dos anos anteriores. Foram elaborados diagramas de dispersão, visando à análise exploratória e à visualização gráfica da relação entre as referidas variáveis, assim como análises de correlação de Spearman entre o IIP e o Índice de Breteau (IB) de cada ano, a fim de estimar a qualidade do LIRAa. A análise comparativa dos valores dos IIP e as respectivas TI no período indicou correlação significativa entre estas variáveis apenas em 2011/2012 (rs = 0,479; p < 0,01). Adicionalmente, foi observada correlação entre os IIP e IB. É urgente repensar os parâmetros estabelecidos pela metodologia LIRAa e investir em metodologias alternativas de vigilância entomoepidemiológica, que mensurem de forma confiável o risco de transmissão no território e assim delinear estratégias mais efetivas para o controle dessas arboviroses.

We have shown that Alphaviruses can enter cells by direct penetration at the plasma membrane (R. Vancini, G. Wang, D. Ferreira, R. Hernandez, and D. Brown, J Virol, 87:4352-4359, 2013). Direct penetration removes the requirement for receptor-mediated endocytosis exposure to low pH and membrane fusion in the process of RNA entry. Endosomal pH as well as the pH of the cell cytoplasm is maintained by the activity of the vacuolar ATPase (V-ATPase). Bafilomycin is a specific inhibitor of V-ATPase. To characterize the roll of the V-ATPase in viral replication we generated a Bafilomycin A1(BAF) resistant mutant of Sindbis virus (BRSV). BRSV produced mature virus and virus RNA in greater amounts than parent virus in BAF-treated cells. Sequence analysis revealed mutations in the E2 glycoprotein, T15I/Y18H, were responsible for the phenotype. These results show that a functional V-ATPase is required for efficient virus RNA synthesis and virus maturation in Alphavirus infection.

Brazilian traditional medicine has explored the antiviral properties of many plant extracts, including those from the Brazilian pepper tree, Schinus terebinthifolius. In the present study, we investigated the chemical composition and anti-mayaro virus (MAYV) activity of S. terebinthifolius fruit. Extensive virucidal activity (more than 95%) was detected for the ethyl acetate extract and the isolated biflavonoids. From the ethyl acetate extract of Schinus terebinthifolius fruits, two bioflavonoids were isolated ((2S, 2″S)-2,3,2″,3″-tetrahydroamentoflavone and agathisflavone), which showed strong virucidal activity against Mayaro virus. Furthermore, several other compounds like terpenes and phenolics were identified by hyphenated techniques (GC–MS, LC–MS and HPLC–UV), as well as by mass spectrometry. Immunofluorescence assay confirmed antiviral activity and transmission electron microscopy revealed damage in viral particles treated with biflavonoids. The data suggest the direct action of the extract and the biflavonoids on the virus particles. The biflavonoids tetrahydroamentoflavone and agathisflavone had strong virucidal activity and reduced MAYV infection.

Nitazoxanide (NTZ) is effective against helminths and numerous microorganisms, including bacteria and viruses. In vivo, NTZ is metabolized into Tizoxanide (TIZ), which is the active circulating metabolite. With the emergence of SARS-Cov-2 as a Pandemic agent, NTZ became one of the molecules already approved for human use to engage clinical trials, due to results in vitro showing that NTZ was highly effective against the SARS-Cov-2, agent of COVID-19. There are currently several ongoing clinical trials mainly in the USA and Brazil involving NTZ due not only to the in vitro results, but also for its long-known safety. Here, we study the response of Vero cells to TIZ treatment and unveil possible mechanisms for its antimicrobial effect, using a label-free proteomic approach (LC/MS/MS) analysis to compare the proteomic profile between untreated- and TIZ-treated cells. Fifteen differentially expressed proteins were observed related to various biological processes, including translation, intracellular trafficking, RNA processing and modification, and signal transduction. The broad antimicrobial range of TIZ points towards its overall effect in lowering cell metabolism and RNA processing and modification. The decreased levels of FASN, HNRNPH and HNRNPK with the treatment appear to be important for antiviral activity.