Experimental Dengue Virus Type 4 Infection Increases the Expression of MicroRNAs-15/16, Triggering a Caspase-Induced Apoptosis Pathway.

The World Health Organization has estimated the annual occurrence of approximately 392 million dengue virus (DENV) infections in more than 100 countries where the virus is endemic, which represents a serious threat to humanity. DENV is a serologic group with four distinct serotypes (DENV-1, DENV-2, DENV-3, and DENV-4) belonging to the genus Flavivirus, in the family Flaviviridae. Dengue is the most widespread mosquito-borne disease in the world. The ~10.7 kb DENV genome encodes three structural proteins (capsid (C), pre-membrane (prM), and envelope (E)) and seven non-structural (NS) proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5). The NS1 protein is a membrane-associated dimer and a secreted, lipid-associated hexamer. Dimeric NS1 is found on membranes both in cellular compartments and cell surfaces. Secreted NS1 (sNS1) is often present in patient serum at very high levels, which correlates with severe dengue symptoms. This study was conducted to discover how the NS1 protein, microRNAs-15/16 (miRNAs-15/16), and apoptosis are related during DENV-4 infection in human liver cell lines. Huh 7.5 and HepG2 cells were infected with DENV-4, and miRNAs-15/16, viral load, NS1 protein, and caspases-3/7 were quantified after different durations of infection. This study demonstrated that miRNAs-15/16 were overexpressed during the infection of HepG2 and Huh 7.5 cells with DENV-4 and had a relationship with NS1 protein expression, viral load, and the activity of caspases-3/7, thus making these miRNAs potential injury markers during DENV infection in human hepatocytes.

Replication of Rocio virus in primary cultures of mouse neural cells.

OBJECTIVE: This study verified the replication efficiency of the Rocio virus in a primary culture of mouse neural cells. METHODS: Mixed primary cultures (neurons/glia) obtained from the brains of newborn isogenic BALB/c mice were inoculated with Rocio virus on the 7 th day of culture, and the development of cytopathogenic effects was monitored. The infection was confirmed via immunocytochemistry (anti-ROCV), while viral replication was quantified in infected primary cultures. The titration method used depended on the infection period. RESULTS: Rocio virus efficiently infected primary cultured neural cells, with the highest viral titer causing cytopathic changes was observed at 2 days post infection. The virus-infected primary culture survived for up to 7 days post infection, and viral load quantitation showed viral replication kinetics compatible with the cell death kinetics of cultures. CONCLUSION: The findings of this study suggest that mouse neural cell primary cultures support Rocio virus replication and could be used as an alternative system for studying Flavivirus infection in the central nervous system.

Replication of Rocio virus in primary cultures of mouse neural cells

ABSTRACT Objective This study verified the replication efficiency of the Rocio virus in a primary culture of mouse neural cells. Methods Mixed primary cultures (neurons/glia) obtained from the brains of newborn isogenic BALB/c mice were inoculated with Rocio virus on the 7 th day of culture, and the development of cytopathogenic effects was monitored. The infection was confirmed via immunocytochemistry (anti-ROCV), while viral replication was quantified in infected primary cultures. The titration method used depended on the infection period. Results Rocio virus efficiently infected primary cultured neural cells, with the highest viral titer causing cytopathic changes was observed at 2 days post infection. The virus-infected primary culture survived for up to 7 days post infection, and viral load quantitation showed viral replication kinetics compatible with the cell death kinetics of cultures. Conclusion The findings of this study suggest that mouse neural cell primary cultures support Rocio virus replication and could be used as an alternative system for studying Flavivirus infection in the central nervous system.