Bovine lactoferrin activity against Chikungunya and Zika viruses.

Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Belém, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Belém, PA, Brasil.Universidade Federal do Estado do Rio de Janeiro. Instituto Biomédico. Departamento de Bioquímica. Rio de Janeiro, RJ, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Belém, PA, Brasil.Universidade Federal do Rio de Janeiro. Instituto de Bioquímica Médica Leopoldo de Meis. Programa de Biologia Estrutural. Rio de Janeiro, RJ, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Belém, PA, Brasil.Chikungunya (CHIKV) and Zika (ZIKV) viruses are arboviruses which have recently broken their sylvatic isolation and gone on to spread rampantly among humans in some urban areas of the world, especially in Latin America. Given the lack of effective interventions against such viruses, the aim of this work was to evaluate the antiviral potential of bovine lactoferrin (bLf) in their infections. Through viability, plaque, immunofluorescence and nucleic acid quantification assays, our data show that bLf exerts a dose-dependent strong inhibitory effect on the infection of Vero cells by the aforementioned arboviruses, reducing their infection efficiency by up to nearly 80 %, with no expressive cytotoxicity, and that such antiviral activity occurs at the levels of input and output of virus particles. These findings reveal that bLf antimicrobial properties are extendable to CHIKV and ZIKV, underlining a generic inhibition mechanism that can be explored to develop a potential strategy against their infections

Drosha, DGCR8, and Dicer mRNAs are down-regulated in human cells infected with dengue virus 4, and play a role in viral pathogenesis

Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Dengue virus (DENV) and its four serotypes (DENV1- 4) belong to the Flavivirus genus of the Flaviviridae family. DENV infection is a life-threatening disease, which results in up to 20,000 deaths each year. Viruses have been shown to encode trans-regulatory small RNAs, or microRNAs (miRNAs), which bind to messenger RNA and negatively regulate host or viral gene expression. During DENV infections, miRNAs interact with proteins in the RNAi pathway, and are processed by ribonucleases such as Dicer and Drosha. This study aims to investigate Drosha, DGCR8, and Dicer expression levels in human A-549 cells following DENV4 infection. DENV4 infected A-549 cells were collected daily for 5 days, and RNA was extracted to quantify viral load. Gene expression of Drosha, Dicer, and DGCR8 was determined using quantitative PCR (RT-qPCR). We found that DENV4 infection exhibited the highest viral load 3 days post-infection. Dicer, Drosha, and DGCR8 showed reduced expression following S.M.M. Casseb et al. 2 Genetics and Molecular Research 15 (2): gmr.15027891 ©FUNPEC-RP www.funpecrp.com.br DENV4 infection as compared with negative controls. In addition, we hypothesize that reduced expression of DGCR8 may not only be related to miRNA biogenesis, but also other small RNAs. This study may change our understanding regarding the relationship between host cells and the dengue virus

Comparative Genomic Analyses of New and Old World Viscerotropic Leishmanine Parasites: Further Insights into the Origins of Visceral Leishmaniasis Agents

Visceral leishmaniasis (VL), also known as kala-azar, is an anthropozoonotic disease affecting human populations on five continents. Aetiologic agents belong to the Leishmania (L.) donovani complex. Until the 1990s, three leishmanine parasites comprised this complex: L. (L.) donovani Laveran & Mesnil 1903, L. (L.) infantum Nicolle 1908, and L. (L.) chagasi Lainson & Shaw 1987 (=L. chagasi Cunha & Chagas 1937). The VL causal agent in the New World (NW) was previously identified as L. (L.) chagasi. After the development of molecular characterization, however, comparisons between L. (L.) chagasi and L. (L.) infantum showed high similarity, and L. (L.) chagasi was then regarded as synonymous with L. (L.) infantum. It was, therefore, suggested that L. (L.) chagasi was not native to the NW but had been introduced from the Old World by Iberian colonizers. However, in light of ecological evidence from the NW parasite’s enzootic cycle involving a wild phlebotomine vector (Lutzomyia longipalpis) and a wild mammal reservoir (the fox, Cerdocyon thous), we have recently analyzed by molecular clock comparisons of the DNA polymerase alpha subunit gene the whole-genome sequence of L. (L.) infantum chagasi of the most prevalent clinical form, atypical dermal leishmaniasis (ADL), from Honduras (Central America) with that of the same parasite from Brazil (South America), as well as those of L. (L.) donovani (India) and L. (L.) infantum (Europe), which revealed that the Honduran parasite is older ancestry (382,800 ya) than the parasite from Brazil (143,300 ya), L. (L.) donovani (33,776 ya), or L. (L.) infantum (13,000 ya). In the present work, we have now amplified the genomic comparisons among these leishmanine parasites, exploring mainly the variations in the genome for each chromosome, and the number of genomic SNPs for each chromosome. Although the results of this new analysis have confirmed a high genomic similarity (~99%) among these parasites [except L. (L.) donovani], the Honduran parasite revealed a single structural variation on chromosome 17, and the highest frequency of genomic SNPs (more than twice the number seen in the Brazilian one), which together to its extraordinary ancestry (382,800 ya) represent strong evidence that L. (L.) chagasi/L. (L.) infantum chagasi is, in fact, native to the NW, and therefore with valid taxonomic status. Furthermore, the Honduran parasite, the most ancestral viscerotropic leishmanine parasite, showed genomic and clinical taxonomic characteristics compatible with a new Leishmania species causing ADL in Central America

Environmental influences on antibody-enhanced dengue disease outcomes

Because an enriched environment (EE) enhances T-cell activity and T-lymphocytes contribute to immunopathogenesis during heterologous dengue virus (DENV) infections, we hypothesised that an EE increases dengue severity. To compare single serotype (SS) and antibody-enhanced disease (AED) infections regimens, serial intraperitoneal were performed with DENV3 (genotype III) infected brain homogenate or anti-DENV2 hyperimmune serum followed 24 h later by DENV3 (genotype III) infected brain homogenate. Compared AED for which significant differences were detected between the EE and impoverished environmental (IE) groups (Kaplan-Meyer log-rank test, p = 0.0025), no significant differences were detected between the SS experimental groups (Kaplan-Meyer log-rank test, p = 0.089). Survival curves from EE and IE animals infected with the AED regimen were extended after corticoid injection and this effect was greater in the EE than in the IE group (Kaplan-Meyer log-rank test, p = 0.0162). Under the AED regimen the EE group showed more intense clinical signs than the IE group. Dyspnoea, tremor, hunched posture, ruffled fur, immobility, pre-terminal paralysis, shock and death were associated with dominant T-lymphocytic hyperplasia and presence of viral antigens in the liver and lungs. We propose that the increased expansion of these memory T-cells and serotype cross-reactive antibodies facilitates the infection of these cells by DENV and that these events correlate with disease severity in an EE

Persistence of experimental Rocio virus infection in the golden hamster (Mesocricetus auratus)

Rocio virus (ROCV) is an encephalitic flavivirus endemic to Brazil. Experimental flavivirus infections have previously demonstrated a persistent infection and, in this study, we investigated the persistence of ROCV infection in golden hamsters (Mesocricetus auratus). The hamsters were infected intraperitoneally with 9.8 LD50/0.02 mL of ROCV and later anaesthetised and sacrificed at various time points over a 120-day period to collect of blood, urine and organ samples. The viral titres were quantified by real-time-polymerase chain reaction (qRT-PCR). The specimens were used to infect Vero cells and ROCV antigens in the cells were detected by immunefluorescence assay. The levels of antibodies were determined by the haemagglutination inhibition technique. A histopathological examination was performed on the tissues by staining with haematoxylin-eosin and detecting viral antigens by immunohistochemistry (IHC). ROCV induced a strong immune response and was pathogenic in hamsters through neuroinvasion. ROCV was recovered from Vero cells exposed to samples from the viscera, brain, blood, serum and urine and was detected by qRT-PCR in the brain, liver and blood for three months after infection. ROCV induced histopathological changes and the expression of viral antigens, which were detected by IHC in the liver, kidney, lung and brain up to four months after infection. These findings show that ROCV is pathogenic to golden hamsters and has the capacity to cause persistent infection in animals after intraperitoneal infection