Investigation of the anti-influenza activity of siRNA complexes against the cellular genes FLT4, Nup98, and Nup205 in vitro

Objectives. Evaluation of changes in the viral activity of influenza A/WSN/33 after complex knockdown of combinations of cellular genes FLT4, Nup98 and Nup205 in human lung cell culture A549. Methods. The work was carried out using the equipment of the Center for Collective Use of the I. Mechnikov Research Institute of Vaccines and Sera, Russia. The authors performed transfection of combinations of small interfering ribonucleic acid (siRNA) complexes that cause simultaneous disruption of the expression of cellular genes FLT4, Nup98, and Nup205. Within three days from the moment of transfection and infection, the supernatant fluid and cell lysate were taken for subsequent viral reproduction intensity determination using the titration method for cytopathic action. The dynamics of changes in the concentration of viral ribonucleic acid (vRNA) was determined by real-time reverse transcription polymerase chain reaction (real-time RT-PCR). The nonparametric Mann–Whitney test was used to calculate statistically significant differences between groups.Results. Using all of the combinations of siRNA complexes, cell viability did not decrease below the threshold level of 70%. In cells treated with complex FLT4.2 + Nup98.1 + Nup205 at the multiplicity of infection (MOI) equal to 0.1, a significant decrease in viral reproduction by 1.5 lg was noted on the first day in relation to nonspecific and viral controls. The use of siRNA complexes at MOI 0.01 resulted in a more pronounced antiviral effect. The viral titer in cells treated with siRNA complexes FLT4.2 + Nup98.1 and Nup98.1 + Nup205 decreased by 1.5 lg on the first day. In cells treated with complexes FLT4.2 + Nup205 and FLT4.2 + Nup98.1 + Nup205, it decreased by 1.8 and 2.0 lg on the first day and by 1.8 and 2.5 lg on the second day, respectively, in relation to nonspecific and viral controls. When conducting real-time RT-PCR, a significant decrease in the concentration of vRNA was noted. At MOI 0.1, a 295, 55, and 63-fold decrease in the viral load was observed with the use of siRNA complexes FLT4.2 + Nup98.1, Nup98.1 + Nup205, and FLT4.2 + Nup98.1 + Nup205, respectively. On the second day, a decrease in vRNA was also observed in cells treated with complex A. A 415-fold decrease in vRNA on the third day was noted in cells treated with complex FLT4.2 + Nup205. At MOI 0.01, the concentration of vRNA decreased 9.5 times when using complex B relative to nonspecific and viral control.Conclusions. The study showed a pronounced antiviral effect of siRNA combinations while simultaneously suppressing the activity of cellular genes (FLT4, Nup98, and Nup205), whose expression products are playing important role in the viral reproduction process, and obtained original designs of siRNA complexes. The results obtained are of great importance for the creation of emergence prophylactic and therapeutic drugs, whose action is based on the mechanism of RNA interference.