Effect of siRNA targeting dengue virus genes on replication of dengue virus: an in vitro experimental study

Dengue is a notorious viral infection, which affects a large segment of world populations in absence of vaccines and anti-viral treatment. The current study evaluates role of effective siRNA in dengue virus replication. Eight siRNA were synthesized against five different genes (Capsid, CprM, NS1, NS3 and NS5) of all serotypes of dengue virus. All serotype of DV were transfected with all synthesized siRNA in vitro, using BHK-21 cell lines. Culture fluid from test and control was tested by Real time PCR for CT value comparison in siRNA treated cell line (test) and untreated cell line (controls). Percent knockdown (%KD) was calculated by ∆∆C_T methods to know the difference in test and control CT value. It was found that siRNA targeted against capsid gene worked best and showed inhibition of all four DV serotypes. DV-1, DV-2, DV-3 and DV-4 showed 93.8%, 99.3%, 87.5% and 93.8% knock down (%KD) respectively by siRNA targeted against capsid gene. Additionally, Si2 (target CprM gene 60-899) and Si 6 (target NS1 gene 3007-3025) were also showing inhibition of replication. Most serotypes of DV (with few exceptions) were not inhibited by siRNA targeted against NS-1, NS-3, and NS-5 genes. Animal studies using siRNAs are warranted to establish their therapeutic role.