Phylogenetic relationship of dengue virus type 3 isolated in Brazil and Paraguay and global evolutionary divergence dynamics.

BACKGROUND: Dengue is the most important mosquito-borne viral disease worldwide. Dengue virus comprises four antigenically related viruses named dengue virus type 1 to 4 (DENV1-4). DENV-3 was re-introduced into the Americas in 1994 causing outbreaks in Nicaragua and Panama. DENV-3 was introduced in Brazil in 2000 and then spread to most of the Brazilian States, reaching the neighboring country, Paraguay in 2002. In this study, we have analyzed the phylogenetic relationship of DENV-3 isolated in Brazil and Paraguay with viruses isolated worldwide. We have also analyzed the evolutionary divergence dynamics of DENV-3 viruses. RESULTS: The entire open reading frame (ORF) of thirteen DENV-3 isolated in Brazil (n = 9) and Paraguay (n = 4) were sequenced for phylogenetic analysis. DENV-3 grouped into three main genotypes (I, II and III). Several internal clades were found within each genotype that we called lineage and sub-lineage. Viruses included in this study belong to genotype III and grouped together with viruses isolated in the Americas within the lineage III. The Brazilian viruses were further segregated into two different sub-lineage, A and B, and the Paraguayan into the sub-lineage B. All three genotypes showed internal grouping. The nucleotide divergence was in average 6.7% for genotypes, 2.7% for lineages and 1.5% for sub-lineages. Phylogenetic trees constructed with any of the protein gene sequences showed the same segregation of the DENV-3 in three genotypes. CONCLUSION: Our results showed that two groups of DENV-3 genotypes III circulated in Brazil during 2002-2009, suggesting different events of introduction of the virus through different regions of the country. In Paraguay, only one group DENV-3 genotype III is circulating that is very closely related to the Brazilian viruses of sub-lineage B. Different degree of grouping can be observed for DENV-3 and each group showed a characteristic evolutionary divergence. Finally, we have observed that any protein gene sequence can be used to identify the virus genotype.

Nec-1 protects against nonapoptotic cell death in cisplatin-induced kidney injury.

BACKGROUND/AIMS: Necrostatin-1 (Nec-1) inhibits necroptosis, a nonapoptotic cell death pathway. Acute kidney injury (AKI) is a clinical problem of high incidence and mortality. It involves several mechanisms of cell death. We aim to evaluate the effect of Nec-1 in the toxic kidney injury model by cisplatin. METHODS: We analyzed the effect of Nec-1 in AKI by cisplatin in human proximal tubule cells by flow cytometry. RESULTS: Our results show that Nec-1 has no effect on apoptosis in renal tubular epithelial cells (Nec-1 + Cis group 13.4 ± 1.7% vs. Cis group 14.6 ± 1.4%) (p > 0.05). But, in conditions in which apoptosis was blocked by benzyloxy-carbonyl-Val-Ala-Asp-fluoromethyl ketone (z-VAD-fmk) the use of Nec-1 completely reversed cell viability (Nec-1 + Cis + z-VAD group 72.9 ± 6.3% vs. Cis group 35.5 ± 2.2%) (p < 0.05) suggesting that Nec-1 has effect on nonapoptotic cell death (necroptosis). CONCLUSION: Our findings suggest that the combined use of apoptosis and necroptosis inhibitors can provide additional cytoprotection in AKI. Furthermore, this is the first study to demonstrate that Nec-1 inhibits tubular kidney cell death and restores cell viability via a nonapoptotic mechanism.